Author: Guthman Signs

*Editors Note: We were lucky enough to be given permission by Matthew Ward to compile his 14 pt series on the history of Modular Displays to post to our blog. We hope you enjoy it!

A Re-Introduction to Modular Display History

Long after the last 4:3 aspect ratio plasma TV was produced the LED display industry was producing almost everything but a 16:9 display. There is a good argument for 8:9 ratio displays but that is not what the industry coalesced around as a loose standard. LED panels that are 600 mm x 337.5 or the imperial cousin of that format have come to dominate the permanent install market. At some point one company or perhaps a few companies started moving in this direction and the industry (and the specifiers and the clients) followed. This article looks at a couple steps along that path.

The motivation for these articles is to gather information on the LED display market between 1994 and 2008. Much of the product information from this time is trapped on paper or in old floppy disks. There is a link to the current archive in the comments after the article. Take a look at what we have gathered and please reach out if you have anything to add to the archive.

A: History is about vectors. Bringing a point of view to a subject. But this point of view is often too narrow to accurately characterize a specific period of time in much the way the “Great Man” theory of history turned out to be a poor indicator of what actually happened, how it happened, who did it, and the role of luck and privilege in the whatever event is being chronicled. Everything happens in a context and a slight change in perspective can deliver a very different story.

B: So, my dude, what does this have to do with stacking televisions?

A: I think that oversimplifies things a bit. We will discuss “stacking televisions” but we will approach the topic from a number of different angles. You could look at this as a complementary modular approach to the history of modular display.

B: JUMBOTRON!

A. Yes. Jumbotron.

B. JUM-BO-TRONS!

A. One way to look at that is as part of the arc of cathode ray tube development but you can also just look at it as part of the history of branding. Jumbotron is Sony’s proprietary name for a specific large format outdoor display and the name was probably more successful than the product.

B. And you can fix it with a tennis ball on the end of a stick!

A. And what else can we fix with a tennis ball on the end of a stick?

B: (silence)

A: So you are ready to learn the history of modular display?

I always picture this as a conversation. One of the most interesting aspects of this business has been the social aspect of it. The idea that at a certain point in time we were all dealing with the same not entirely fully baked products because we were part of this industry. You and I may have arrived at this point in our lives along different paths. But right now it is 01:00 AM and we are both starring at a piece of equipment that is not behaving the way it usually behaves and someone back at the factory is telling us that “they have never seen it do that before”.

How many ways are there to dice up the modular display market?

The first step is to look at the core display TECHNOLOGY. Projection (CRT, LCD, DLP, other), Emissive (CRT, Plasma, laser, LED, OLED), Transmissive (LCD, MEMS shutter), and Reflective (Mechanical, Bi-stable, Transflective). Are there others?

The hardware is used across a wide range of APPLICATIONS including touring, live events, exhibitions, art installations, control rooms, laboratories, and corporate lobbies. The product that is used in an install is often different from the product used on an event. There is cost associated with flexibility that is typically stripped out from products intended for the installation market.

The next step is to look at the mechanical FORM of the various elements in the system. Are there rules that follow across technologies? Are there material and process advances that allow for new forms that were previously impractical? Can we make generalizations? And what about the nature of the emergent display technologies opened up opportunities that could not have been used effectively in legacy technology platforms?

The DATA architecture of the system is clearly important. Video wall systems largely revolved around processors that drove individual display modules for a big chunk of history. Processing has a cost and distributing it was expensive. But now most LCD and LED systems are capable of some degree of internal data distribution. So there has been an optimization around an approach that simplifies physical cabling and reduces overall cost. But that does not work for all systems. So what are the rules of system topology?

The application ENVIRONMENT certainly impacts the design of a modular product. The need to manage environmental concerns such as water and salt have a significant impact not just on the design of a product but on the design and manufacturing process since tests must be designed to validate the environmental protections. The thermal requirements of denser indoor displays are an equally important factor in the design of those displays.

A layer down in the stack and the word MODULAR comes up again. From a development point of view, the LCD stack or the OLED stack are closed INTEGRATED systems for all but the largest companies. This compares with the LED industry where an open MODULAR market exists. But the parts are often the same in a sense. They are driver companies in the LCD business and driver companies in the LED business. So what is the difference? Is it open MODULAR low volume version closed INTEGRATED high volume?

What is the impact of the INDIVIDUAL on the industry and on the products and the evolution of the market? Early in the development and adoption process, there are certainly parts of this industry that favor individualism and personal vision. Product segments don’t really define themselves. As Edna Mode says “luck favors the prepared”.

What about DESIGNERS? There are clearly moments when the industry is dragged forward by the vision of a designer. And the acceptance of well-managed risk on the part of a designer bringing a new product forward is a critical part of how this industry has evolved.

Can we look at the “author” of the product? Some of the products that arrived on the market are the result of a rigorous development process grounded in complete written specifications paired with established operational and manufacturing processes that are tied to testing programs. Products from Barco and Christie would tend to fall in this category. Other products are haphazard free form affairs where an idea is rapidly moved from concept to prototype to show because some driving internal vision or external need is driving development. I think the first Element Labs products were more like this. Is something like that visible in the tree of modular display life?

To a degree, this has been the world of beta hardware. Products manufactured at relatively low volumes in comparison to other commercial or consumer hardware. The goal of this series is to put that into a broader context that helps us understand what comes next.

This was a fishing expedition. If you have documentation from the LED display industry between 1995 and 2008 please reach out. Images of projects are great but technical documentation of the framing systems is the focus at this point. We will start there and move to processing and software.

Please the  link to the Google Drive holding the current information I have gathered (read only) and a list of credits and thanks. Special thanks to the Tom Mudd and the team from Invision Microsystems for the help on the previous post.

This article is dedicated to John Rigney [1956 – 2020]. John was an iconoclast. One of the first people in the United States to rent LED hardware.

Modular Display History: Part One

[This was originally a stand alone post on Linkedin. I am reposting as an article for the sake of continuity – Check out the original post for the comments. There are a few interesting threads. LINK]

Wanted: Help trying to reconstruct the history of the modular display industry from CRT displays through the late 2000’s.

Like any old database the internet is getting a bit crufty around the edges and in the middle and other spots. Cleverly parsed search queries can only get you so far particularly if you have forgotten the manufacturer name and other key terms have become generic.

But it is also possible that some of these documents never made it to the point where there was a useful PDF that could be downloaded from a website. Some documents only existed on individual hard drives and FTP sites. And some information never made it past the printed one sheets and catalogs distributed at sales events.

To try to remedy this I am putting together a Dropbox to gather some initial information. My hope is that this then becomes a Wiki or some other easily searchable public resource available to designers, researchers, patent examiners, and bored technicians locked in their homes putting together fantasy show preproduction leagues. If you are the person who made good use of your time and recycled all of this last week please just keep that to yourself.

Any and all help is appreciated. Thanks.

The article stopped there but I have since posted the contents to a publicly accessible Google Drive. In the next couple days this will be mirrored to Tencent Drive for LED people in China. A good chunk of the contents in the folder come from Tom Mudd but many people have contributed to this effort including but not limited to Robbie Thielemans, Bob Magee, Bob Kronman, and several manufacturers.

 

Modular Display History: Part Two

There is some great work by Robert Simpson on the history of video walls from the early 1980’s through the late 1990’s. This work naturally focuses on displays composed of cathode ray tubes and rear projection cubes and on the importance of software that offered video designers the tools that were previously only widely available to analog multi-image programmers.

This bit from Blooloop [November 2009] is topical.

”The videowall emerged in the early 1980s. Whether it originated in Europe, the USA or Japan is a matter of debate, but two factors affected what was achieved. First was the fact that early videowalls were all based on standard CRT (Cathode Ray Tube) monitors, typically 28 inch diagonal, with the resulting large gap between image sections. Second was the difficulty of achieving the “image split”, that is the means by which a single input video signal could be split into, say, 16 separate image signals to produce one large”

The apt phase “a matter of some debate” also applies to the beginning of the LED industry. As with the development of the blue LED there were multiple teams working on a solution up to a point and there was very early awareness that light emitting diodes could be used in a display. Work on the blue LED had been progressing in the late 1980’s and into the early 1990’s.

“One day,” Maruska recalls, “I was in a hotel in 1990, and there’s a knock on the door, and Akasaki is outside the door. He looks in, and he shines this blue LED in my eyes and says, ‘look at this!’ I say, ‘holy shit! It’s actually a bright blue LED!’ He says, ‘yes, it is.’ And he just disappears down the hall.”

https://spectrum.ieee.org/tech-talk/tech-history/silicon-revolution/rcas-forgotten-work-on-the-blue-led – Forgive the click bait headline. The story is worthwhile.

The identify of the first company to ship a proper full color LED display is — a matter of some debate. Tony Van de Ven (Cree, Lighthouse) tells a story about having to reject an order from Proquip in 1996 because the Cree green LED was yellow-green and Cree would not buy a true green LED from Nichia and so Cree declined the work. Sunrise Systems, in Massachusetts (US), installed a full color screen at Harvard in 1995. Opto Tech, in Hsinchu (TW), installed a full color screen in New Zealand around that time. QSTech (CN) was doing work around this time and installed a screen in 1996. And Invision Microsystems (UK) was building screens as discussed in a previous post. Gundermann (DE) is a likely suspect. Trans-Lux (US) was producing line drawings of what would become familiar LED cluster designs. And Chromatek (JP) exhibited a full color LED screen at Inter BEE in 1996 and went on to drive the many excellent Hibino screens that followed.

These first LED video displays used a wide variety of mechanical formats and system topologies built upon their past experiences in specific market segments that evolved out of their vision of the future of the market and how the technology needed to be used. Some of these system were modeled on Jumbotron/Diamondvision/Astrovision. Some built on the networked lighting modules used in signage. This is an interesting point in time because there are certainly templates but there is no roadmap. There is no reference design.

Twenty-five years later and the LED display industry is a vital global business with manufacturing on the verge of moving from a modular model (assembly of driver and LED components into display modules at manufacturer integrator) to a monolithic model (assembly of LED display modules in a fab).

Modular Display History: Part Three

“that’s not how I would do it”

The LED business inherited the metal box from signage companies. Brake form metal boxes are incredibly flexible and can be made at a reasonable cost in whatever size is required. It is possible to add doors and gaskets for outdoor use. The Lighthouse 102 series 10 mm SMD display and the Hibino SMD display were both built with brake form boxes. Toshiba and others adopted this model and Frederic Opsomer was involved in many of these designs.

The theory I propose here is that there are a limited number of primary forms in the modular display business. Specifically that there are three forms.

Metal Box – The box is an enclosure that contains all the bits including a structural element that connects through the box to allow mechanical connections with other panels. The box is a contains all the other components but the mechanical load is passed through another feature (a tube or column) that is installed in the box.

Space Frame – An open modular framing system that defines the size and shape of the display and holds the display modules. Everything connects to the frames including other frames.

Exoskeleton – A single unit that integrates the electronic and mechanical systems. Everything connects and references to the shell. And structural load passes through the shell of the unit.

Innovation did not stop with the launch of the third option. It is possible to hybridize across these forms to some degree. And it is also possible to approach them in new ways.

When Barco designed the iLite series of LED panels they moved to a space frame each of which contained a single large display module. ILite was an evolution of Dlite, an outdoor system that also used a space frame. While conceptually there was such a thing as a single unit of Dlite the structure was focused on large contiguous walls for installs and touring. Creative people like Georg Roessler (send me Saab pictures Georg) might deploy a distributed Dlite system but this was not supported in the mechanical system. When I asked Robbie Thielemans why Dlite looked so different from previous LED products he told me he that it was supposed to look like a “product, not a project”.

For Ilite the space frame offered a number of advantages over the metal boxes. The frame could be milled for accuracy. It was easier to swap out the electronics once the system was installed. Additionally the square format was more readily adapted to more creative arbitrary display configurations. Most critically it offered rental companies was a viable path to a 6 mm product and this was something that designers and end clients wanted.

Because of Barco’s strong rental & staging partner program Ilite was dominant in the rental market through the mid 2000’s. In fact Ilite was so successful that it was never displaced from this position by the innovative carbon fiber NX series that was intended to replace it in the market. The NX, a space frame, may not have been the first LED panel to integrate carbon fiber but it was the most widely distributed carbon fiber product for a period of time.

The next evolutionary step in high resolution screens was Element Labs Cobra panel. The monolithic cast aluminum exoskeleton handles all mechanical functions. Cobra was a solid exoskeleton so it was not a space frame and it was not a brake form metal box. To a degree it borrowed from some larger format screens that preceded it but it also integrated a number of new features that had not been delivered in a high res display. Cobra also looked better from backstage than any screen in history.

Another round of innovation in panel design started after the 2008 financial crisis. While many products were derivative of existing products there are also products such as ROE’s Black Onyx that redefined the rental market. A shift from exoskeleton back to space frame. Companies based in Shenzhen will dominate the rental & staging market for the decade that followed the financial crisis.

The install market consolidated around a variety of exoskeleton based 16:9 aluminum panel designs. One of the goals here is to understand how these designs evolved and what companies drove the standardization around that form fact. Leyard, AOTO, Liantronics, Desay, QSTech, Unilumin, DigiLED and the list goes on. It would be good to understand the history here. In Europe Eyevis developed a different type of panel focused on installs as did Planar in the United States. Both these designs took a different layered approach to the problems typical of permanent installs.

There is a parallel evolutionary path that I am glossing over that starts with the Japanese LEC screen (the predecessor of GLEC) and Tam Bailey’s LED net. Low res mesh screens on a path that eventually leads to the Komaden screen and onwards to Element Labs’ Stealth. From there it is a short hop to the Korean LED companies and the carbon fiber Winvision Air design. The Winvision Air panel is a space frame and it is possible to argue that Stealth is also space frame of a sort. These products applied a strong point of view to areas of the market that were underserved by existing products. The engineering was clever and the products appeared radically different but the form itself follows established patterns.

The goal is to dredge up documentation so that there is an online archive that documents the early stages of the LED industry. I am certain that I have missed details and overlooked notable products. That is the point. We rely on selective memory and are dependent upon what people were exposed to. We are basing our history on stories told at bars or at trade shows. And on LinkedIn posts during pandemics. Having a more robust archive of this information would be helpful to many people.

Modular Display History: Part Four

In the beginning there were PCBs and ribbon cables and large driver boards and power supplies. There were small PCBs each in a housing with a discrete louver and there were large PCB subassemblies. Some had lenses. And like the great Permian extinction few if any of these designs have survived to the present day. Soon, in the mid-1990’s, the commercial introduction of the blue LED would lead to an explosion of new display topologies.

Geoff Lunn related this story to Tom Mudd in a thread discussing the history of Invision Microsystems.

Exchanges like this are our starting point. People had their Red-Green displays and they thought they made white and they liked it that way. This is before the transition to surface mount electronics. Before the introduction of the three-in-one SMD package that came to define the successful Lighthouse and Barco LED displays of the early 2000’s. And before the introduction of the 16:9 cast aluminum frame that has come to dominate the market for fine pitch install screens. How did we get from an ad hoc bunch of large screen display enthusiasts putting pins though holes in PCBs to an industry standard of sorts driving most of the specs for fine pitch LED installations?

Barco launched NX4 in 2007 with an 8:9 aspect ratio and radical carbon fiber space frame. But the install variant had a much more simple frame. This was a cost driven decision and the resulting design had a lot in common with the Olite frame. Element Labs made slightly different decisions on the install variant of Cobra opting to design the casting so that the latches could be replaced with fixed mounting plates. NX4 was used in the Comcast install in Philadelphia. This is the first real iconic lobby LED install. At the time a 4 mm install LED display was the cutting edge and this was a massive architecture scale install. But the 8:9 ratio would seem to indicate that Barco felt like this product would be primarily used to make typical 16:9 video displays while the square iLite product would continue to be used in large arbitrary media surfaces.

Silicon Core brought the Orchid 1.9 mm panel to market in 2011 with a 8:9 aspect ratio. The panel was built around a large format aluminum plate supporting six LED boards and a central control box. The frame featured some elements that exist in products today. A flat front plate locating the LED boards with a rear housing for the power supply, the receiver cards, and a hub board.

A few years later Eyevis and Planar both introduced LED install products built around a layered design concept that more closely mirrors the approach of other trades in architectural interiors. Both companies supplied projection and LCD video wall systems to integrators and they needed to add high resolution LED to their offerings. The companies were more focused on providing complete solutions to integrators and so the products reflected a different set of priorities.

Hartmut Weinreich, now at Technikkonzepte GmbH, worked on the development of the EyeLED-M at Eyevis and confirmed this.

A space frame system can be built and leveled before the electronics are installed. Adjustments for the X, Y, or Z axis are easily accessible to the installation team as would reference points that can be used with a laser level or a plumb bob to confirm that the screen was flat before the installation of the electronics. The new Eyevis system had all the bells and whistles that a high end integrator would want.

The Planar DirectLight X included something called the “EasyAlign mounting system”. This follows the same pattern. The framing system can be installed and alignment handled before the LED tiles are installed. Planar included two levels of Z-axis adjustment and remote power supplies in their system.

Within a few years of these product introductions Unilumin, AOTO, Leyard, Liantronics, QSTech and others were all shipping 16:9 install panels at a variety of price points and the cost advantage of these products was too much to ignore. Both Eyevis and Planar are now part of Leyard but at the time Eyevis was working with Unilumin. While the EyeLED-M had a strong point of view Unilumin were offering LED panels in a 16:9 format that were much more cost effective. Desay introduced a 16:9 install product in 2017. ROE, Yaham, and many others now have 16:9 products in the way that narrow bezel LCD displays are largely 46” or 55”. This is now a high volume business with manufacturers targeting different market segments while sticking to this de facto standard form factor.

The next phase is refinement. ESDlumen came up with a simplified lighter weight panel. Digiled worked on a prototype called Wafer that went on to become Digithin [see image of a prototype of Digithin below courtesy of Graham Burgess]. There is a clear focus on wall mounted installation and the need to move away from the complicated and expensive framing systems that are required for most front service installations.

The CreateLED AirIM is an interesting outlier. These are small 200 mm x 150 mm modules with a lot of built in intelligence. Four to six modules roughly the size of the AirIM go into most 16:9 panels. CreateLED have eliminated the larger panel entirely and moved to put all the intelligence into smallest viable component. A network of modules. Each LED display module incorporates power distribution and a receiver card and there is a cost associated with moving all of that into such a small package. More connectors. More mechanical connections. This is something that you can expect late in a development cycle in the way that LCD manufacturers are moving memory into the pixels. The CreateLED approach points to the high level of product integration that may be the future of fine pitch LED.

I end this week not really knowing who introduced that first 16:9 panel. This is the internet though and I am certain someone wants to enlighten me. Graham Burgess mentioned that he believes the 16:9 panels started slightly smaller with a 500 mm width and scaled up to the 600 mm width, a move that helps with unit cost and allows similar wall sizes to the 55” narrow bezel product. This also gets manufactures close to the imperial system and some manufactures introducing products that are two feet wide (609.6 mm).

 

Modular Display History: Part Five

Shenzhen serves the entire LED display market from the high end to the low end. It extends from the cutting edge back through time to displays that are largely unchanged from their introduction almost twenty years ago. It is into this market at some point between 2012 and 2016 that the Shenzhen Public Frame came to be. How this happened is unclear but the story involves VER, XL Video, Peter Daniel, DigiLED, Everbrighten (KR), Absen (CN), Infiled (CN), and ESDLumen (CN) and a variety of other players. The actual story is somewhere between The Irishman and The Righteous Gemstones.

 

The Shenzhen Public Frame is not a single frame but rather a range of vaguely related iterative or derivative frames available through the casting companies and various middlemen in Shenzhen. The Shenzhen Public Frame encompasses a core mechanical capability available to any company creating an LED product. If you go to the LED China show you can buy a frame and then move on to select LED display boards, an LED processor, a road case. All you need to do is put your name on the back and you too can be “a manufacturer”. And some companies have gone this route but so have some very good LED companies that also use that form factor. They pay for their own castings and have designed them to optimize for specific customers or around the different market verticals. Companies have shaved weight of the designs and moved to magnesium alloys or made the frames chunkier to handle touring. A design team can use the frame as a stable high volume platform and build something new on top of it. Some of these 500 mm x 500 mm panels, like the ROE Black Onyx, have redefined the entire market with their innovations being absorbed back into the public template. This all points to the strength of the format.

The Shenzhen Public Frame starts with a die cast space frame that utilizes a central support oriented in a horizontal or vertical direction depending on the design of the control box that sits just behind the frame within which there is a power supply and a hub board that connects to four LED display modules mounted to the front of the frame. There are variables and there are a limited number of forms but any LED technician looking at just the frame could tell you what it was even if it was a manufacturer they had never heard of before that moment.

There is a logical progression from 37 mm to 25 mm to 15 mm to the early primordial 10 mm and 6 mm predecessors to the Shenzhen Public Display frame. The central spine from the Element Labs Stealth product or competing Barco Mitrix product ran along a central section of PCB that connected to the data and power electronics that could not be minimized. As the resolution increases the size of that “spine” increases. This is particularly true with the larger power supplies required to run outdoor LED products. An odd early example (2003) of this center spine layout is Element Labs VersaTILE, a product that shipped in 500 mm x 500 mm and 1 meter x 1 meter panels.

In 2008 some 500 mm x 500 mm panels were produced by Gtek for Pete’s Big TV and AG Lighting for a Bruce Springsteen tour. Why 500 mm x 500 mm? One version of the story is that it has to do with Peter Daniel of Pete’s Big TV chasing an advantage of a little over one millimeter of resolution against a competitor. The 500 mm panel supported 32 pixels at 15.625 mm and this gave Peter a resolution advantage over the Winvision 18 panels from VER. It is 32 pixels because the panel size was optimized around driver and processor costs and at this point in evolution a change in resolution often meant a change in panel size because sufficiently large multi-pixel driver ICs were not on the market. Each driver controlled a small number of LEDs. And then each panel needed a receiver card to handle the data distribution (In China this was typically from a Linsn LED processor). A manufacturer wanting to move from 18.125 mm to 15.625 mm might move from 580 mm x 580 mm panel to 500 mm x 500 mm panel.

XL Video had been an early supporter of South Korean manufacturers, using panels from Basictech, Everbrighten, and Winvision. But at some point they were outflanked when VER cut exclusive deals with Everbrighten and Winvision. XL had to rush to replace that equipment and the compressed version of the story is that they ended up sticking Kristof Soreyn on a plane to Shenzhen looking to make what would become PIXLED F-15 (PIXLED was XL Video’s sales and manufacturing arm). F-15 was essentially a copy of the Everbrighten product that had been spec’d for the tour. Crisis averted Kristof started working with Absen on PIXLED F-6, a high brightness 6 mm outdoor product at 500 mm x 500 mm that came to market in the fall of 2011.

Around the same time Peter Daniel enters the story again. Peter was in Shenzhen with Graham Burgess of DigiLED and Mitch Kaplan of Videowalltronics to visit Leyard for the factory acceptance test of a screen that Mitch had ordered. They made a stop to visit Infiled to meet with Michael Hao and during this visit the group hashed out the design for the what became the DigiLED MC7 panel. Peter wanted a panel that would compete with the Winvision 9 mm product at VER and in order to stay within the driver and processor math they ended up with a 7.8 mm screen in a 500 mm x 500 mm panel (a 64 pixel x 64 pixel matrix). This panel came to market in early 2012.

Starting in 2012 there are a cascade of product introductions that build on die casting, standardize around a 500 mm x 500 mm panel size, and use a defined central control box. The Viss Pandora 10 is 500 mm x 500 mm. Absen, Esdlumen, Newstar and various other companies appear to be working with that size. But there are also companies working with other square formats. Unilumin, Esdlumen, and other companies had square products at 480 mm x 480 mm.

In 2012 Absen introduced the A series of LED panels at 3 mm, 5 mm, 7mm. Absen specifically notes the use of die casting and the standardization around a single size across multiple pixel pitches. The A series is a hybrid with a central control box similar to the PIXLED F-6 but with a full covered back.

The Esdlumen Rock (640 mm x 640 mm) series was introduced as a more simple product but in 2014 it gains a central control box that feels like the template for many other products to come. The shape has been adapted. It is no longer a flat folded box but a cast part. There are angles that help with cabling. This product builds on the products Esdlumen had introduced over the previous year with the Mini (480 mm x 480 mm) and Micro series panels. There is a mix of die casting and different control boxes but you can see the product designers working out the ideas.

At this point there are many companies with products at the edge of what we think of as modern LED products. Newstar and CreateLED are both showing square panels with central control boxes in 2014.

The launch of ROE Black Onyx in 2014 crystalized for many people the potential of a 500 mm x 500 mm LED product. ROE was not known for high res products at this point in time. ROE had developed creative product like LED mesh. Black Onyx identified all the key trends and requirements in the high res market and delivered them pulling in major international clients like Creative Technology.

At this point this format is universal. Sold directly and indirectly all over the world this is perhaps the first global LED platform. I could name all the manufacturers with product in the image above but they represent a fraction of the manufacturers, resellers, trading companies, and sales agents selling product in this form factor.

BONUS FEATURE: Tom Mudd does a deep dive on the 1998 DCM15 LED Screen Panel from Invision Microsystems Ltd

Modular Display History: Part Six

There was a moment in 2002 or 2003 when it seemed like there was only one company making LED display for the indoor rental market which is pretty good given that Barco had not even shipped an LED product prior to 1999 and did not ship an indoor product until 2001.

If you wanted an indoor LED screen in 2002 or 2003 your options were Barco, Hibino, Lighthouse, and not much else. In the outdoor market there were some additional companies including Saco, Yesco, Opto Tech, Unitek, Daktronics, Sony, Mitsubishi, and a few others. It is important to understand that many companies at this point are buying complete LED subassemblies from Nichia. Either boards or LED clusters. This may have contributed the strong industry response to the MiraVision demo at NAB in 2002 because there were rumors that this screen was produced in tight cooperation with Nichia.

Barco had considered buying its way into the market and also met with companies like Lighthouse to look at partnerships but eventually the company opted to support an internal development effort led by Robbie Thielemans.

When making the decision to pursue internal LED display development back in 1998 there was not a lot of information to go on. The indoor market overall was very small at the time. From a rental & staging point of view there were at best a few companies that had SMD based LED panels. The outdoor market was stadiums and specialty advertising. When a company was getting into the stadium market half the conversation related to insurance bonding and the competition (Daktronics) was entrenched. Music touring was moving to LED but everything else was a guess. There were still companies working on LED-alternatives such as plasma.

At Photokina (Germany) in 1998 Barco showed an internal project code named Punch (a brand of Belgian beer). This was an LED display demo that was “literally a cookie box” with holes milled in it where the 6 mm oval LED packages peeped through after the application of silicone potting. But ideas make their way from sketches to mock ups to prototypes. So when Robbie says “imagine a cookie box with holes” it is hard not to jump ahead to the DLite or the ILite panels that would follow. But as simple as this demo was it was not far from the basic architecture for outdoor displays with the DIP packages potted to protect the lead frame from the elements. The panel did demonstrate an almost complete processing pipeline that would go on to appear in the DLite system.

DIP stands for Dual In-Line Package – This is the more official designation for lamp based screens that are also called Pin Through Hole. The DIP package came out of Fairchild Semiconductor. Why is it a DIP switch? That is why. The early LED market was dominated by DIP screens. Screens characterized by different fall-off in the red, green, and blue packages along with the slight variations in orientation of the LED packages after insertion and soldering. Tony Van de Ven at Lighthouse quietly advocated not trimming the pins tight to the back of the PCB because the long pins acted as a heat sink. And so ends this tangent.

Not everyone expected Barco to enter the LED market. Legend has it that Tony Van de Ven, who had hosted Barco when they visited Lighthouse in Hong Kong earlier in 1998, made his displeasure felt. Punch was not a huge success at the show but Barco was determined to deliver a fully realized outdoor LED panel at the ISA show in 1999. To meet that time table certain pieces of existing equipment were at least temporarily pulled into the design. The RCVDS projection switcher was used as a processor. A line doubler was repurposed as a digitizer for mapping the signal to the LEDs. The DLite panels included calibration and used DVI, which was robust from a pixel mapping point of view and in no other way.

One thing Barco did entirely from scratch was the mechanical. Here the work with the cookie tin paid off. The DLite panel did not join the family of large brake form panels that were the standard in the outdoor display market. Instead it was a fully modular system. The DLite panel was much smaller at 448 mm x 448 mm meaning that rental companies would have some granularity when specifying displays. Barco would go on to supply 2×3, 2×2, 3×4 and other touring structures to their rental & staging clients. They showed up in big road cases which was always very strange.

The size of the panel was partially driven by the design of the control electronics. The backplane had to be under 400 mm x 400 mm because of limits on surface mount production lines that were used by Barco at the time. The board included the three Altera FPGAs (1 red, 1 green, 1 blue) that drove the panel. The control board was larger than any of the four LED modules that fit onto the front of the D7 panel.

Another thing that Tony Van de Ven (and Lighthouse in general) took issue with was the virtual pixel approach used by Barco. The discrete red, green, and blue LEDs in a D7 pixel could be combined with LEDs from an adjacent pixel to form a third new pixel. The 14 mm D7 could therefore be presented as a 7 mm screen. Lighthouse pushed the advantages of their pixel accurate approach and in some cases interpolating these virtual pixels was not desirable and D7 owners would not use that feature. In 2020 when a large number of 4K video projectors are made with non-4K imagers the debate seems quaint. Discrete color LED displays lend themselves very well to this sort of manipulation in the right circumstances with the right content. There is every reason to expect that we will see the re-litigated in microLED display space.

Barco followed up DLite with an indoor SMD product called ILite. Ilite came out in 2001. The plan was to launch with a 7 mm product but Barco shifted to 6 mm because they wanted a 1mm edge on Lighthouse. This is all happening around the same time as Lighthouse’s failed 5 mm Osram based COB product.

The ILite panel was 448 mm x 448 mm as was the Punch demo from 1998 so it is possible to make the assumption that the size of this very successful family of products was dictated by what size cookie box was available for the Punch demo. But ILite followed a different mechanical model than the DLite product. ILite used a cast magnesium frame that integrated all of the mechanical interconnection. There was no need for a separate rental frame in order to build an ILite wall. This frame was redesigned once the rigors of life on the road became apparent. The frame housed a LED panel with a removable input module that allowed a user to replace a panel without loosing signal to the rest of the wall. To the best of my knowledge this was unique at that point in time.

The first customer for ILite was Georg Roessler who bought the product after a demo and an all-nighter from the Barco team. Georg purchased a small amount for an auto show. Barco ended selling a lot of ILite to pretty much every rental & staging company but a large early customer for the product was VER and these purchases would transform the LED market over the next few years. Renting modular LED displays to a broad market as a dry hire company was not the same as renting projectors or cameras.

ILite went through a few generational changes (XP and BK) before being displaced by products from Korea and China. From Ilite Barco went on to experiment with COB and OLED and release products like MiPix, MiSphere, and OLite. Barco experimented with coated versions of ILite for television studios. One of the mock-ups during this period of time put COB LED modules on the ILite frame. This is well before flip chips and long before this effort stood any reasonable chance at success. But this is how we learn. Barco did eventually ship some very small 3 mm display modules and sold some into a Louis Vuitton install in Paris.

 

Modular Display History: Part Seven

In a bar in Hong Kong in 1999 Frederic Opsomer and I mapped out the future of the LED industry. There were napkin sketches. Tragically none of these survived. We imagined an LED market full of creative products and sets composed of various types of LED. I think I described something that would evolve into VersaTILE a few years later. A desire to push low res LED in a different direction as more of a material. This was a lot less obvious than it might seem. Manufacturers were laser focused on shifting to higher and higher resolution. A few years later I would get together with a bunch of like minded people (Chris, Claas, Jeremy, Marian, and Nils) to found Element Labs. But that is a story for another time. Today we are going to look at the evolution of the LED display industry as reflected in one man’s journey from carrying bulky televisions around discos for a Belgian rental house to designing the mechanical system for PRG that would allow U2 to tour Joshua Tree with a massive wall of ROE CB8.

There are several links in the body this article. Some of the stories are very well covered and if you are interested the links are there. There is some crossover with an article that Jerry Gilbert wrote for Lighting & Sound (PLASA) in 2016. You might not remember it because it was before Covid-19 so here is the link to that article which also features a nice although not exactly comprehensive or entirely correct section on Element Labs. Again, a story for another time.

THE PRELUDE

Luck favors the prepared. Let us set the scene. A young Frederic Opsomer is working for Video Image Processing (VIP), the Belgian rental house mentioned above. He had started out dragging large CRT monitors into discos to do marketing for cigarette companies and moved up through the company. VIP eventually purchases a Philips Vidiwall system and VIP is doing work on auto shows for brands like Peugeot and Renault. Philips was at the time a large diversified electronics company that also owned Polygram Records and Polygram had a band called U2 and U2 had a designer named Willie Williams and Willie had big plans. And those plans did not include the Philips Nitstar (an LCD based outdoor screen with a nickname that ended in -itstar) and so now everyone needed to find an alternative video display to use on the European leg of ZooTV where the GE Talaria video projectors being used in the United States were not going to work in the extended daylight hours of European summer. Frederic said that VIP turned around a quick mockup with Barco and that U2 quickly made the decision to go with VIP and the as yet not designed Digiwall.

“We brought them to Barco the next day and they saw our first attempt of a cube which was really a tin can.” Two days later the band had confirmed with VIP and “we had three months to develop a rigging cube”. There were a number of problems that needed to be addressed. First, nobody was touring projection cubes at this point in time in any meaningful way. Second, When you installed a projection cube it worked best if you never touched it again. Third, this was a massive surface that would eventually fill seven trucks.

The resulting product looks more like the Electrosonic Procube than any of the Japanese projection cubes (Pioneer and Toshiba). It is a generally featureless box with a screen on the end the light comes out and input and projection electronics on the other side. The boxiness likely simplified the design and that was a necessity given the amount of time.

You can clearly see the center load point in the image above based on the mechanical fasteners on the sides and the two rigging points at the top. You can also see four alignment pins at the corners. The nice thing about projection cubes is they are a giant waste of space because they are mostly full of air. There is a lot room around the projector to wrap the structural components. And if it were not for the impending arrival of higher resolution LED products it is likely that this approach would have been improved upon iteratively to reduce the depth, reduce the weight, and make the projection engine and the signal distribution system more robust.

So why was Frederic prepared? What made VIP the right company? “If I go back from the very early days when we were carrying television sets in disco clubs. Those god damn things were not meant to be carried in disco clubs. So what did we do? We started with putting special profiles, special handles, … in 1985 it was already about how do you make things transportable and easy to handle” As a company, there were people within VIP that were prepared to think about a video display in terms of how it could be adapted to the work that was required. And this adaptability was critical to delivering the equipment on this tour.

Another reason that ZooTV is fascinating in the context of these articles is that the technical and tour documentation does not appear to exist on the internet. The articles that would have appeared in Light & Sound or Entertainment Design or some other industry magazine do not appear to have made it online. You can now typically find an article with at least a gratuitous list of hardware and the names of the crew people. In light of that here are some very incomplete credits for the tour (Including arbitrary hellos to friends): Production designer & director Willie Williams, Architect Mark Fisher, Tour director Jake Kennedy, Production director Stephen Iredale, Project manager Richard Hartman, Video engineer Dave Lemmink, Video programming Jim Vastola, Lighting of all birds John Lobel, and somewhere pushing a case Tim Halle. Frederic Opsomer and some of the VIP crew also obviously playing a big role day to day.

Last week I mentioned the substantial impact of x-Barco employees on the LED industry. Once the ZooTV tour was over some staff at VIP started to look at other opportunities. System Technologies was founded by Frederic after he left VIP in 1995 and XL Video was founded by Rene and Marcel DeKeyzer in1996. These are the last two ingredients in the global Belgian LED mafia.

PHASE ONE – 700% the screen in 29% of the trucks

This is the story of the design and realization of the U2 PopMart tour. The timing of this design makes it an important moment in the development of modular LED displays. Versions of this story are available in many places (like here). Willie Williams and Mark Fisher conceived of a massive LED screen for the next U2 show at some point early in the summer of 1996. The timing was good for LED but not great. Companies had started to produce full color LED video screens at the time (Invision Microsystems, Opto Tech, QSTECH, and Sunrise) but there was not a company that was actively manufacturing screens at this scale. In fact 1996 was probably the first year in history that more than one company was producing a full color LED display. Some companies at this time could not supply a true green LED package. And the majority of LED signal distribution was either direct DC voltage or short TTL runs and neither of these approaches in combination with ribbon cable lent itself well to a large distributed system.

A number of tests were conducted including one at Brilliant Stages in the UK. Willie Williams has provided some video and describes the test as “showing what is very likely the world’s first lo-res LED video screen prototype. This is hanging up at Brilliant Stages’ old place out at Greenford and consists of some LED ‘pixels’ attached to cable ribbon and spaced a very ambitious 9” apart, or thereabouts. You can see that we demoed it during the day which was equally ambitious but, hey, we had high hopes. The massive pile of PC hardware and rats’ nest of cables to the rear was our ‘media server’. I was there with Mark Fisher and Richard Hartman, as well as Jake Kennedy, U2’s then production manager, who you see run through the shot.”

1996_VideoNet at Brilliant Stages from hugoboom on Vimeo.

Notes on the video – The hand in the video on the LED net likely belongs to Richard Hartman. The tech waving towards the end of the video is Tam Bailey, the designer of the screen.

In November 1996 this became an R&D project with Frederic. Frederic now needed to identify a partner for the electronics and design a system that would fit in two trucks, protect the electronics, and load in and out smoothly. It is worth noting that there was no internet and that global GSM mobile phone accessibility was still something of a new thing. Frederic had done some research and lined up some places to visit. There were probably fax machines involved. Frederic first visited Opto Tech in Taiwan. Opto had an LED cluster that they were using or planning to use in stadium installs. But Opto are an engineering driven company. They have an incredible store of knowledge about LED display panel design but at their core are cautious. This would have been far outside of their comfort zone at the time. The next stop was Panasonic who also had an LED cluster along with a visit to another possible partner in Osaka. The company in Osaka was producing LED modules with an eye on the advertising market. Frederic was not convinced that any of these companies would make the right partner. He eventually landed at Saco in Montreal via a referral from a possible vendor in New York.

Fred Jalbout, one of the founders of Saco, could be forgiven for assuming that the Belgian man visiting his office was wasting his time when he sent Frederic off to the airport with a signed letter giving System Technology exclusivity for a tour by a band whose name Fred Jalbout had not recognized. That impression changed when Frederic returned in ten days with Willie Williams, Mark Fisher, Richard Hartman, Jake Kennedy, and a few other people. By the time they left Saco had been selected to supply the LED systems for a screen produced by System Technologies. The opening date of the tour was in April 1997 in Las Vegas. This allowed for less than six months for design, sourcing, manufacturing, assembly, and delivery to Las Vegas … followed by more assembly.

The design is straightforward. A lot of thought went into how to engineer frames that would fanfold into place show after show while maintaining alignment and protecting the electronics in transit. There was no template for how to build this screen. The design utilized aluminum slats (referred to as tubes on the tour) that were mounted on frames that hinged together so that the whole screen folded up. The system rolled in on set carts and they got the install time down to three hours. Each panel in the system had a frame that supported the LED strips and some control electronics and connected to the adjacent frames in the system.

You can see the detail above of the eight DIP LED packages poking through the aluminum profile. These would eventually be potted or repotting during the tour because this is the process of designing the bicycle while ridding it in traffic. In the context of the earlier article on Invision Microsystems it is interesting to see two blue LEDs with the three red LEDs and three green LEDs. One of the reasons that a person could look at the red/green screen and think that it was making white is that the human eye is a relativistic device and what it defines as white covers a broad range including a very warm almost yellow glow. It does not take much blue to push that back into a more neutral white.

Another one of the complexities of this entire project is that the process of content development for this tour predates any modern or even Mesozoic previz system. Frederic described a visit by Willie Williams to System Technologies where they “had to go way back in the field between the cow shed” to be the right distance away to see a 4 meter x 4 meter chunk of screen. The actual screen was so large that it was only ever assembled fully at rehearsals in Las Vegas and it worked. The creative team likely did not see a larger chunk of screen until they arrived in Las Vegas.

Some incomplete credits for the tour (Including arbitrary hellos to friends): Show design & direction Willie Williams, Architect Mark Fisher, Screen imagery by: Roy Lichtenstein, Keith Haring, Run Wrake, Leigh Bowery, John Maybury, Jennifer Steinkamp, Vegetable Vision, Straw Donkey, Curator of screen imagery Catherine Owens, Tour director Jake Kennedy | Holly Peters, assistant, Production director Stephen Iredale, Production manager Clifford N. Levitt David Herbert, assistant, Pre-production Project Manager Richard Hartman, Lighting Design Willie Williams, Sound designers Joe O’Herlihy, Lighting director Bruce Ramus, Lighting consultant Allen Branton, Icon operator Tom Thompson, Tour camera director Monica Caston, Media engine software design Dave Lemmink, Assistant engineer and a man now looking for a new place to do cool things Stefaan Desmedt, Ropeoplogist John Lobel.

The PopMart tour established LED at the center of concert touring. And yet it still took many years several waves of manufacturers to make that happen. Frederic would go on to work on some other products with Saco such as the 18 mm screen that Dave Crump would purchase for Screenco to use on the Janet Jackson Velvet Rope tour. System Technologies also delivered a heart-shaped LED floor for Celine Dion’ Let’s Talk About Love tour.

PHASE TWO – LED Panels are a business

In 1999 Frederic was doing some work for Hibino on the Tokyo Motor Show when he had a conversation with Graham Andrews (Creative Technology). Graham suggested that Frederic go talk to Tony Van de Ven at Lighthouse in Hong Kong. Creative Technology had recently been one of the first companies to purchase the Lighthouse 102C 10 mm SMD panels and the frames were truly horrible.

One very expensive one-way plane ticket later and Frederic was in Hong Kong to meet with Tony. Lighthouse was on the verge of a very good run of sales as they had no real competition at this point and the Lighthouse 102C was far more capable, at what I think was 400 nits, than any of the rental companies had thought it would be. The mechanical design was a problem but it was a problem that fit within Lighthouse’s cost structure. The Lighthouse panels were perhaps the first LED display panels exported out of Shenzhen to western rental companies. The panels were manufactured at Desay and according to Tony he could get a frame in Shenzhen at that point for two-hundred and fifty dollars. This was far cheaper than the frames Frederic was currently producing in Belgium and Frederic understood the effect that would have. He would eventually stick an entire brake form shop in shipping containers and send it to Shenzhen so that Lighthouse could start to build their own frames.

Lighthouse replaced the 102C with the 102D (pictured) and the product went on to be very successful. It is a completely recognizable folded metal box with a central rigging pin and a pair of guide pins and cam-locks to side to side connection. There was access to the modules and the power supply from the back.

This work for Lighthouse led to work for Toshiba and other companies in addition to the work Frederic was already doing for Hibino. When Toshiba moved to 6 mm the frames shifted to aluminum extrusions and System Technologies had to introduce CNC milling to get to the required tolerances. In some ways, this work had more impact on the market than PopMart. The shift to brake form and eventually aluminum extrusion (typically housed in thin sheet metal shells) created an identifiable model that could be emulated. You could see what System Technologies was doing and copy it. And other people could improve on that. Copying PopMart only made sense if you were trying to do the PopMart tour (see Westerhagen Screen). And that crew had already nailed that. But if you paid attention to what System Technologies and eventually Lighthouse were doing you could quantify exactly what customers expected in an LED rental product and you could build a design around that. So in effect, Graham Andrews pointing Frederic Opsomer to Tony Van de Ven helped created an industry consensus around what the commodity LED market was going to be. You could now make a box and a customer would look at it and think “that is an LED panel”.

CONCLUSION

As I noted at the beginning of the article Frederic is still working on massive LED projects. The PRG Spaceframe for the ROE CB8 on the U2 Joshua Tree tour is not that different a mechanical challenge to PopMart. Different technology and a different solution. We have only covered the first couple of years in this article. The work on distributed LED systems and products like MiSPHERE and FLX will be covered in another article.

System Technologies would become independent again in 2001 and then sell itself off to Barco in 2005. Frederic now works at PRG running the PRG Projects group where he is pondering Real Reality as a counterpoint to Augmented/Mixed/Extended Reality. He is thinking of the RR that will follow the XR. How do we recover from this as an industry? When will audiences feel that it is now OK to be back in a crowd?

Thank you to Frederic Opsomer and Willie Williams for assistance with this article. The copyright for the images and the video are retained by their original owners and any use outside the context of this article would be frowned upon.

And finally, a link to a video that Tom Mudd posted featuring Arthur Jackson talking about Invision Microsystems from 1997.

 

Modular Display History: Part Eight

For article number eight we address a period of transition in the LED display industry. Barco was the driver of the industry for a decade. Companies measured themselves against Barco. Companies even rearranged the letters of Barco to make tongue in cheek product code names. By the end of the decade Martin, Winvision, Everbrighten, and Absen had all come to market to dethrone Barco. Daktronics made several attempts to enter the Rental & Staging side of the LED market. PIXLED and DigiLED both sold products into the rental market. Barco gave the market confidence that we weren’t all just making it up as we went but by the time we get to 2011 or 2012 they were no longer a significant presence. I believe I had this exact conversation with Graham Burgess at ISE around this time. A market like the LED market needs a company to carry the banner because this helps communicate to customers the direction of the market and the vitality and quality that can be expected. It makes it easy for customers to understand where the market is headed so that they can plan ahead. This is particularly true in a market like LED where the products were evolving rapidly.

In 2006, and just out of college, Jason Lu started a company called Radiant Opto Electronic Technology in Shenzhen. 2006-2009 was just about survival for Radiant. At this time Jason did not have a specific vision for the company but he understood that he needed to offer something different. The LED market had only recently diversified beyond the basic metal boxes. Creative LED products had been coming to market but it was not clear at the time what these were about and how large the market was and it was much easier to simply make higher volume LED displays delivered in metal boxes. But Radiant instead created a series of LED mesh products. Jason spent a lot of time looking at what other companies were doing and ended up with a business model that would revolve around being responsive to customers. This may not have been a conscious decision. The mesh products were new so perhaps this appeared to be a better point of entry for a new LED display company. But lower resolution creative displays also have a way of highlighting the flaws in a data distribution design or a bad ground plane and the systems are very sensitive to poor mechanical design. I am reminded of the story Shuji Nakamura tells about why he started to research blue LEDs. Nobody else was doing it and he thought this was an easy way for him to get some papers published. This may have looked like a less complicated path forward for Radiant but it presented a lot of problems and many young companies would have failed during this time. The decisions Jason made during this period of time would forge to the new company’s personality.

2009 was an important milestone for Radiant. Kristof Soreyn (XL Video) & Stephan Paridaen (who had, until recently, been running Barco) visited Guangzhou to attend LED China to find some manufactures in China. One item on Kristof’s to do list at the show was to find a low res screen for an upcoming Bon Jovi tour and he determined that the Radiant Linx37 would work.

Kristof next visited the Radiant factory which was very small at the time. Grace Kuo described the meeting at the factory like this — Kristof asked Jason ”young man, can I trust you?” and Jason said “Yes”. Then they made this deal which was very important for Radiant. After that project, leading companies in this industry learned about Radiant.

This starts to feel like a pretty typical moment in our industry. Man ends up at factory (it is always a man which is something we must remedy as we move forward as an industry – I would appreciate any examples to the contrary) and the man makes a judgement call on whether to proceed with that vendor based on feel. Can I work with this person? Do they come across as understanding the technology? Do they speak my language? Will they support me when there are problems? In the previous article Frederic Opsomer did not go back to Belgium and do a long drawn out extended engineering validation and certification process before deciding he wanted to go with Saco as the vendor on PopMart. He had enough confidence that they were able to return with a large group in a little over a week. And Kristof Soreyn did not do a tear down followed by a month of highly accelerated stress screening and lift testing along with customer consultations. This is partially driven by the small scale of the industry and the results do not always play out so well.

Above is an early version of Linx-37 with 5050 LEDs and white connectors. Linx is a simple product, right? Just a bunch of LED boards daisy chained together. It hangs. It gets rolled up. There are dozens of board to cable to board connections. There are fiddly little mechanical hinges between each board.

This is a later version of Linx with black connectors. You can see the more robust build with the ribs paired up. There are fewer mechanical and electrical connections. The design makes a lot more sense.

In May of 2010, on a regional VER junket, Keith Harrison, Susan Tesh, and Marc van Eekeren visited Radiant. By this point Radiant had a series mesh of products available including Linx, Swift, and EZ Curtain. VER ordered an LED screen based on this visit and there were some issues with the order but Jason made some adjustments and shipped complete replacement system. Jason and the company made an impression on Keith Harrison with the service and support but according to Grace Kuo the company still was not breaking through to the larger corporate market. “The Linx series is unique but was for a very niche market. I still remember that I sent quite a lot emails to Dave Crump (Creative Technology) and Graham Andrews (Creative Technology), but I would never get a response since they had no interest in that product.”

Grace divides the company history into three phases. The first four years were about survival but also education. The second phase was about internalizing what was learned. 2012 would be a year of transformation. The phase may have started out with creative products influenced by Element Labs, Hibino, and Barco but in 2012 Radiant would introduce the Magic Cube series with a complete touring frame and dolly. Radiant would go on to sell over 20,000 square meters of Magic Cube.

Magic Cube delivered an entire range of pixel pitches covering most of what was needed in concert touring at the time. It looks like it might have come out today but now it would be available in a double height version at 600mm x 1200 mm. It follows in the footsteps of the Komaden screen, and Stealth, and the South Korean mesh screens from Winvision, Everbrighten, and Basictech.

XL Video would continue to be a big Radiant customer but the MC series brought other customers in the door and 2012 also brought enhanced access to capital as Radiant sold 60% of the company to Unilumin. In 2013 Radiant would officially change the company name to ROE Creative Display.

As much as the focus in this series of articles is on the history of the modular display hardware this business is also a collection of people. One of the things that I tell people when I try to explain the success of ROE is that there are a group of companies in the industry that are open in their engagement with customers and partners. They allow themselves to be transformed through these relationships. It is a real partnership. This ability to listen and adapt is what defines companies like ROE and disguise. Yes, there are other things to running a successful company (selling things for more than it costs to make them) but what pulls you from Radiant in 2006 to ROE Creative Display in 2013 is listening to clients and supporting partners and seeing the opportunities with clear eyes. Black Onyx would come out in 2014. The rental & staging LED market now had a leader again and the interregnum was over.

Modular Display History: Part Nine

“I just have a few forms for you to fill out …”

When LED video display manufacturers in 1995 and 1996 sat down at their work stations with their bulbous cathode ray tube based monitors to specify what customers would require of their new LED products they would reference experience. The market, like the “new world”, is a test of conforming things to your expectations until your expectations fail to adequately capture what you encounter. Bias confirmation in design. The future would be a lot like today so we are bolting this new adaptation onto our existing templates.

Graham Burgess (DigiLED) started out with Sony working on actual Jumbotrons. People still cal them Jumbotrons. —Last Friday my son graduated from high school in a parking lot where the school assured us there would be two Jumbotrons but much to my disappointment they were two outdoor LED screens. How the school was supposed to find working CRT based screens from the mid-90’s is not my problem. I was promised Jumbotrons.— Between 1992 and 1997 Graham had worked through several different companies to make Jumbotron panels suitable for touring. In 1992 Sony was using a subcontractor that worked for JVR (Jongenelen Video Roosendaal) but Sony would eventually move to Tomcat (an open space frame) and then on to VIP, where Frederic Opsomer designed a touring frame. Every step yielded a slightly different product. It was a steady incremental evolution based on a growing understanding of the market.

This evolution of touring solutions (and installation solutions) for Jumbotrons would be the template that many early LED displays companies would follow. The mechanical systems would be like Jumboton frames but a little more thin. And the market developed over time as the applications became better understood and the market produced monolithic die cast frames and space frames and hybrids of the two things. In hindsight this gives the appearance of destiny. But one of the fascinating bits of history in the modular display timeline is “reinvention”. The process of discovering something that had been done in some other segment of the business. And this happens in other industries and across cultures and even within this author’s own personal notebooks. So the Shenzhen public frame obscures what came before it. And the die cast 16:9 install frames obscure that preceded them. The things we use now feel inevitable right up until something new comes along and then collectively we forget about the previous thing.

Tony Van de Ven (Cree and Lighthouse) said something early on that has stayed with me. He said it was all about shifting the intelligence around the system. Where do you put the processing? How smart do you want the module? This is partially a cost thing but also partially a complexity thing. This is why we have receiver cards and hub boards. And it is why the Sony Jumbotron also had a hub board. A board that could extract the pixel data for that subset of the overall display and that could then distribute that information to two or four display modules. The LED display added a lot of complexity to this model because the displays would have more resolution and were dependent on large numbers of DIP ICs that drove the arrays of DIP LEDs. The complexity that was contained within the vacuum sealed glass box of a Jumbotron module (Futaba) or Diamondvision module (Itron) was suddenly on the outside exposed and consuming large areas of printed circuit board. It was necessary to consider the value of putting the driver in the LED cluster versus leaving the driver on a board full of drivers connected to a bunch of dumb LED clusters that could be easily sealed against the environment. What is the value of an intelligent cluster or an intelligent module? You can see a slightly different decision making process at work in the Invision Microsystems screen if you watch Tom Mudd’s teardown.

This all matters for a couple of reasons. There are a lot of different ways to dice up the path from a content source pixel to the optical output of an LED. And there are a lot of different ways to package that display so that it can all be assembled and disassembled with ease. And the way we do it now is not the only way and it may not even be the best way. The move to microLED almost certainly means that hardware designers will have less options available to them when they go to design whatever screen they are designing in 2030. For the people making displays with next generation microLED LDMs (LED Display Modules similar to an LCM – Liquid Crystal Module – used in flat panel display production) the lessons of the last 25 years may need to be set aside because the accuracy required for 0.5 mm pixel pitch display walls will require a new mechanical architecture with much tighter tolerances.

But perhaps another modular technology will appear that will offer superior performance for lower resolution displays. There is still some level of dissatisfaction with the performance of video displays in color rendering relative to print for certain applications. There is room to improve the performance of outdoor advertising displays. Or perhaps there will be a new type of transflexive or transflective outdoor pixel that integrates a new highly efficient light source in a switchable reflective light valve (I am 100% dealing in hypotheticals) or another type of display that offers a low power reflective display capable of high quality CMYK color reproduction (I am obviously actively trying to get more print people to read my articles). For those making new types of modular displays it may make sense to build upon the collected knowledge of the last 25 years. To revisit some decisions that were made in the 90’s or the 00’s or the 10’s before simply bolting these new concepts onto the thing that is popular at the moment.

“Answer for this would trace back to 1992, and just can’t be found.”

QSTECH (Xi-an, China), one of the first LED display companies in China, replied to a request for information and this sentence is critical to me. Once this information is lost we have no way of getting it back. This is our history as an industry.

“In March 1993, QSTECH and Foshan Optoelectronic Equipment Factory jointly developed the VGA and video synchronization LED electronic display screen, which was the first LED display in China at that time. At that time QSTECH didn’t have a specific name for each product, given there were only few products in the market at that time.” The screen below is the first QSTECH screen to be documented.

“In 1993, along with the development of China’s stock and securities industry, domestic LED market started to grow rapidly.” Infocomm Connect is this week. I am sure all your favorite LED partners will be there and would love to see you. And I would not mind if you pointed them to these links. History is important.

LINK TO DISPLAY SURVEY – CHINESE

LINK TO DISPLAY SURVEY – ENGLISH

 

 

Modular Display History: Part Ten

The LED driver is an integrated circuit that does not come up very often unless you are an LED processing company or a handful of other companies specifically focused on developing LED drivers for video displays. The driver might be discussed occasionally in the context of some very specific features or compatibility with a certain processor. If you are responsible for the system design and the bill of materials for an LED display you will think a lot about LED drivers but I am not going to talk about the specific function of LED display drivers in much more detail here and I am going to specifically ignore the bit where you can use LED drivers and MOSFETs to scan LED matrices. Twenty-five years ago only a handful of companies made driver ICs suitable for LED video displays. Many of these early displays were built on drivers from Texas Instruments. NEC, Microchip, National Semiconductor, and other large companies were making driver ICs. Some of them have been consolidated out of existence. There were also a few companies in Taiwan developing drivers.

One of the useful features of the single-pixel LED drivers from Taiwan is that they were designed to be laid out in series and they distributed data by means of a destructive shift register. So 256 pixels of data go down a line to the first driver and 255 pixels come out the other side of that driver in the series and 254 pixels come out the next driver and so on. I generally divide the LED market into dots, lines, and shapes. For the dots and the lines, this driver topology works very well.

Creative LED products don’t follow the rules of panel-based displays. They are sometimes laid out arbitrarily or used in large distributed arrays. The systems are controlled by media servers or emulators or fed ambient or highly structured pre-rendered video loops. Some are thought of as video and some are thought of as lighting. LED Effects (US), Artistic License (UK), Chroma-Q (UK), and other companies approached these products from the point of view of specialty lighting.

This Chroma-Q Color Web above is available on the A.C. Entertainment Technology web site now which is a pretty good product life cycle IMHO for a product that I am pretty sure I first saw in at PLASA in Earls Court.

It is not that different from this current day Leyard-Vteam product.

As noted in the previous article Tony Van de Ven from Lighthouse (HKG) had talked about how you had to make a decision about where you put the intelligence. In that context Tony was just discussing how much processing you put in the panel versus how much work you do in the LED processor. Processing represents both cost and complexity. Lighthouse was a fan of the “IM” or intelligent module so there was some intelligence in the LED display module. Opto Tech (TW) was working on moving the driver into the LED cluster in the late 1990’s. [Patent Link – Hey look at me linking to a patent – Today is the day I became Mike Wood]. Opto Tech referred to this as a “Smart Light Emitting Diode Cluster” (see image detail below). Having a board full of LED drivers with discreet outputs for each LED cluster that screws into the front of the metal box is easy. It is also inefficient. Lots of little cable jumpers each of which must be fished by hand back to the driver board. Most of the early Element Labs displays were built on an LED driver commissioned by Opto Tech. Element Labs also looked at drivers from Silicon Touch (SITI) and Macroblock (MBI).

The advantage of these drivers is that they were developed to go in an LED cluster and this meant that the drivers had to be smaller surface mount components. And that size and the ability to daisy chain drivers would enable a lot of new applications allowing LED string or strings of LEDs to find their way into aluminum extrusions and cargo-netting and other creative applications. Barco would develop MiPix and would go on to use that system to create MiSphere. As described by Robbie Thielemans the MiSphere was basically a packaging exercise and although the results appear to be different the systems are almost identical from an electronics perspective. MiSphere was essentially two-sided MiPix in a translucent ball (see image below where they actually watermarked the diffuser).

Just as panel systems can be lumped into boxes, space frames, and monolithic shells based on an evaluation of how mechanical load passes through the system there must some equally haphazard way of categorizing creative LED products. And this is primarily by driver topology. The volumetric LED system that James Clar made (image below courtesy of James Clar) and the 3D array of MiSphere on U2’s Vertigo tour and the Nine Inch Nails layered stage designs all create three-dimensional volumes of pixels. But each of these systems approached it in a different way. In the case of the Nine Inch Nails design multiple topologies were involved (LED strips, LED mesh, and LED panels).

The Japanese LEC screen [light emitting curtain] and the net prototype for the PopMart tour were some of the earliest sparse LED arrays. Notable volumetric displays from the 2000’s are the Nova Display (the custom volumetric LED screen and not Nova the LED processing company) and the Cubetron. These last two displays share the appearance of strings of glowing ping pong balls.

Frederic Opsomer notes that the Barco FLX system architecture that was used for the U2 360 video screen is the same thing that ran the LED modules in the seats for the London Olympics opening ceremony. So the ability to expand the spacing of the modules in the U2 rig was taken to an absurd level in creating a distributed video surface that filled the seats of a stadium.

What defines LED systems topology is the path from processor to the pixel. A processor could directly output a stream of pixel data in a format the drivers would accept (often TTL) but this limits the size of the system. In a larger system you need something to strip out chunks of pixels and then output the pixel data for each chunk. This is probably why they are called hub boards. The decision relating to where to put the hubs and spokes in the system has a direct impact on where the designer needs to spend money on intelligence and for LED systems “intelligence” generally means a field programmable gate array (FPGA). This is true whether this task is pulling down the right pixels in one specific box or pulling down the right pixels for a series of LED tubes.

The inefficiency of “home run” driver topologies where each pixel has a cable that runs back to a hub board can become a benefit in certain highly distributed systems. In this case even the hubs can feed lesser hubs. The signal flow looks like the org chart in a very orderly company with one output hitting a series of boxes each of which has a number of outputs that feed yet another physically smaller series of hubs each of which ends in a single pixel.

Some detail on the O2 project from CeBIT in 2005. Design by KMS Team and Schmidhuber + Partner, installed by MixedPixels, designed and engineered by Element Labs + Opto Tech. There is also a great video for this project.

In the last decade companies like Pixmob (image below) have developed wireless approaches to this “home run” system topology. Pixmob essentially projection maps a space in IR light. The pixels are all IR receivers (with batteries if needed) allowing for a largely freeform approach to signal distribution and resolving one of the major headaches of LED string – which is “how do I pixel map this without chasing the designer out out of the venue?” Glow Motion offer a similar capability with wireless RF distribution.

The defining feature of creative LED products is the conversation that is had about how to manage the data. That conversation yields a system topology. You can daisy chain processors and you can daisy chain hubs and you can daisy chain LED drivers. You can fork each of these chains to varying effect (for example you can DA the output of a pixel string to mirror that string of pixels). How to best ship the pixel data from the processor to the pixels. It may be simple and it may be incredibly complicated and involve many many retired German ladies popping pixels in the ends of tubes so O2 can have a really cool CeBIT booth. The need to address the pixel data at various points in the system drives the addition of receivers or hubs or controllers that remove chunks of data and break it up as required to create the desired display. And this has made for an incredibly flexible modular form of lighting that is used if a variety of manners.

 

Modular Display History: Part Eleven

Daddy, Where do modular displays come from?

Everybody who has a child knows that they reach an age when they ask the question? Sometimes it is “Mom, If these –so called– engineers are so clever why doesn’t the big TV put itself together?” or “Dad, if they knew they had to deliver it in pieces why didn’t they make it so the pieces fit together?” or “Hey, you are usually traveling but since you are stuck here because of Covid-19 can I tell you that I never realized that there were so many shades of white light! Why even bother pretending it is one thing? Do these people think they are fooling anyone? Oh, and the light in the hallway is out”

It is possible that some of you missed some good links in the previous article. The links are good. And this article is partially about covering some gaps in the previous articles.

For most of us modular displays have been around since we got into the business. Whether it is CRT displays, video projection walls, or the modular Jumbotron and AstroVision displays that once dominated sports venues or the occasional Rolling Stones tour. The need to make substantially larger displays that had either more resolution or more brightness than was afforded by single monitor or projection systems has driven a lot of innovation.

For my purposes here RESOLUTION and BRIGHTNESS are the two most useful lenses through which to analyze this market at a high level. In each case the displays are optimized to address a key requirement. In some cases this limitation is specific the application but sometimes the optimization migrates from one market to the other as the technology matures. An example is potting in LED screens which has been common in high brightness outdoor DIP displays for ages but is now showing up in a new embodiment in next generation displays where it protects COB and surface mount components on very high resolution screens.

Generally it is worth noting that very few of these core technologies were designed for this market but rather the market requirements of the public display market intersected with some existing technology that was then optimized for the needs of the entertainment technology wing of the modular display market. The rental and touring market in particular has been very creative in adapting technology to the requirements of temporary installations and live events.

A notable exception to this was the Mitsubishi modular OLED product that debuted at the CEATEC show in 2010 featuring a 3 mm RGB OLED pixel an a 384 mm x 384 mm module. While Mitsubishi may have shipped and installed some screens the product was clearly too early for the market [useful context for the recent Samsung claims to have invented modular television]. And this may have just been a public relations move on the part of Mitsubishi. At times it feels like 90% of what makes it into the public tech media is R&D press releases. Polished demos that are not even close to mass production.

I have already talked about breaking down display technology into dots, lines, and squares. But the real limitations of modular displays are closely tied to the physical, power, and data requirements of the displays. The need for the mechanical systems to tie an array together within very specific tolerances. The need to supply a wired power source for the displays (resistance is a drag). And last week we started to look at the need for data to pass through the systems along a specific path in order for the data to map correctly to the displays. All these things create limits on what manufacturers and designers can reasonably create. The simple dot (a single pixel at the end of a string) required an annoyingly complex and expensive power and data distribution system before wireless technology decoupled the physical pixel from the data mapping.

Beyond gathering historic information on the early LED market my goal in this series is to look at forms and topologies. If the LED video systems break down into dots, lines, and polygons then what are the basic building blocks of modular display systems. Do the rules of LED apply to other systems? In a conversation with a longtime industry person recently I noted that the creative potential of projection cubes seemed to evaporate as the products became stable and the sizes of the walls increased. That certainly has not happened with LED. Is it that the content systems did not scale to support the larger systems? Did the reliance on legacy video production and distribution cap projection cube walls?

There are some obvious ways of breaking down forms that have been covered in other articles. Boxes/Enclosures, frames, and shells cover most of the products surveyed here. Even non-LED products follow this model pretty directly. Today we are doing RESOLUTION. Next week we will do BRIGHTNESS

HIGH RESOLUTION

What is “high resolution” for the purposes of this article? We are going to carve out consumer displays and hard displays. Retina displays are lovely but we are not there yet. That said the next generation of displays is being discussed in terms of microns rather than millimeters. We will get there. But not today.

The resolution acceptable for indoor displays varies based on viewing distance and application but as a massive generalization for large displays viewed from a meter or so away the numbers seem to fall in the 0.5 mm to 1.2 mm range. At the low end this is the range at which commercial plasma displays entered the market and at the other end you have large format 98” LCD panels and now large meeting room focused LED display over the 120” mark.

The Cathode Ray Tube

This market was once centered around optimized CRT displays manufactured by companies such as Barco, Hantarex [ [http://www.hantarex.com](http://www.hantarex.com) ] and Dotronix [ [https://dotronix.com](https://dotronix.com) ] along with boxy professional displays from companies like Sony (The 2030 and 2530 below). These displays relied on external video processors to split a signal out across the individual displays and a mix of adjustment pots and arcane magnetic adjustments to create an acceptable flat color field across the displays.

These CRTs were, along with input boards and power supplies, mounted in sheet metal boxes that minimized the gaps from active image area to active image area to the highest degree possible. The line art in the manuals and documentation is fascinating retrospectively now that the gaps in displays are so minimal. For starters the displays themselves were not rectilinear. These gaps will remain a focal point in every other display technology moving forward no matter how small they get.

FORM – Note that all the products integrate components into a single housing. This made sense mechanically but the systems also did not feature any components that benefited from being isolated from heat and the neck of the CRT left a lot of dead space for ambient cooling and the large surface area of the housing functioned as a passive heat sink. Alignment was fairly simple with small pins used for vertical alignment and four hole brackets at the back of the displays used for horizontal alignment. The best description of the philosophy behind the mechanical design was “alignment by gravity”. The margin of error was likely well in excess of 2 mm.

The Sony can be viewed as an enclosure but the other products were primarily open folded heavy duty metal frames where tabs on the CRT screwed into the frame at the corners. The strength of the glass likely formed a substantial portion of the structural integrity of the mechanical system. The Dotronix image above is not specifically a videowall image but shows the general look of the displays.

The Projector

Video projectors based on CRTs were also used in large arrays with all the attendant alignment and calibration issues. These were integrated into an open frame system for installations but manufacturers also made fully integrated boxes and while the systems started out as CRT projection systems they eventually moved to novel LCD systems or DLP based projectors eliminating the need for convergence. The addition of solid state light sources also helped sustain projection based video wall systems.

What is fascinating about projection walls is that LCD walls have only just in the last few years achieved the level of narrow bezel that project walls had 20 years ago. So it was not the bezels that killed projection walls. It was depth and complexity.

FORM – The projection systems also required a lot of volume. The systems designed for the rental market integrated all of the electronics into a single housing that was quite often a monocoque design. Again the volume of space required limited thermal concerns. These units generally featured a front and rear alignment connection.

Eventually folded optical paths and the commercial benefits of front serviceable systems limited the amount of space within the rear projection housings and provided some rationale for remote power supplies.

The need for front access and the limitations that the light path placed on the mechanical systems led to novel release mechanisms for the front screen surfaces.

The LCD

More sophisticated versions of this original CRT and projection model exist in the LCD market today with internal scaling and processing and complex mechanical systems that allow for alignment and servicing.

Planar designed an LCD wall system that separated the DC based display components from the AC power components allowing for better thermal management and redundancy on the DC side yielding more robust systems for command and control centers as well as other architectural installations. This is a natural break in an LCD display system as the companies that produce the LCD sub-assemblies sell them as an integrated component called an LCM that includes the LCD glass panel along with a backlight and a timing controller. It is possible to extend the connection from timing board on the LCM to the input by means of a custom LCD controller board.

This division of display electronics and power electronics is important in LCD panels as the source PCB and the switch mode power supply both generate a good amount of heat and in a narrow bezel LCD array there are not a lot of places for that heat to go.

At the moment the market belongs to LCD monitors built on modules from Samsung, LG, AUO, and others and a new generation of OLED products from LG but the transition to LED based systems has begun. And nothing says that more clearly than the Barco Unisee display. The LCD equivalent of that Nakamichi cassette deck that spun the tape 180 degrees to change sides. An amazing piece of engineering that demonstrates how much work LCD companies have to do to justify the margin and compete with LED companies.

FORM – A lot the assumptions changed with LCD as the package is much more dense. The tolerances have become very tight and thermal issues arise that require new approaches some of which were borrowed from the control room market where remote power supplies most likely originated more as a matter of convenience and “serviceability” than necessity.

With a single pixel a little over half a millimeter in a digital system that is less friendly to adjustment than projector or CRT based systems the mechanical alignment of LCD systems has become part of what manufacturers and accessory makers like RP Visual offer to installers. At this level of tolerance small errors compound very quickly.

The LED

There are apparently two types of LED displays. There are actual LED displays and there are TVs with LED backlights that some person in a marketing department decided to call an LED TV and so now people are saying “Direct View LED” to describe actual LED displays. The term Direct View LED did not really exist when the iPhone was launched. And Samsung is exiting the LCD panel business. I just wanted to point that out.

NOTE: We are covering some familiar ground here if you have read some of the earlier articles. But there are some forks here that we did not cover.

The LED market for high resolution is driven by the progressive miniaturization of the surface mount LED packages that started out around 5 mm square and are now smaller than one mm square in high resolution products. The market has also been driven by Shenzhen (and China in general) and the growing sophistication of the suppliers and vendors there as they drive the price of screens down to a level that is practical. The cost of LED packages in China is a critical part of this. Going with a vendor like Nichia, Cree, or Osram can double or triple the cost of a finished screen.

The high res LED market is an an interesting hybrid of the above systems. The LED market is not yet precisely like the LCD market where a range of companies design on top of a high volume LCM but the LED market is most likely headed in that direction as the next generation of technology will be built on subassemblies with higher non-recurring engineering costs favoring much larger businesses with access to capital. This is particularly interesting when you look at a company like BOE. Michael Hao, CEO of Infiled, started his career at BOE but left to join Sinolight in 2006. BOE decided to focus on LCD production in 200 and exited the LED business. But now they are probably looking seriously at ways to move back into LED as a microLED panel supplier.

The move from DIP to surface mount devices allowed for more integrated red/green/blue three-in-one LED packages to be fabricated with predictable performance and yields. LED displays prior to this used through hole LED packages which limited performance. There were three-in-one DIP packages but without a good reflector the color mixing was not as good and the varying orientations of the DIP packages and thermal limitations meant these never became a big part of the display market.

The rental market for high resolution LED started out with a 10 mm LED product that was brought to market by Lighthouse. Following the story of Lighthouse can be baffling with many different people involved early on. The company was partially funded by the Lo family, whose LED packaging company Cotco was eventually sold to Cree.

FORM – The Lighthouse 102C product was the first 10 mm LED product that I used on a show. It was a mechanical failure and was quickly replaced by the 102D. This frame drew on experience designing framing systems for touring Jumbotron and projection cubes systems and it was an immediate improvement over the initial frame.

Lighthouse went on to focus on a product intended to rapidly move to a fine pitch display building on the success of the LVP102D. The new 5 mm product was based on a similar architecture to the 10 mm product. The key difference was that Lighthouse was attempting to make a COB display using a new Osram process and it did not work. This was in 2000-2001 long before the founding of any company involved in the current wave of COB displays. Before the flip chip.

It is important to understand that this was not crazy in 2000. The DIP packages were pretty mature but the ones used in LED displays were not that old. And the shift to surface mount packages was rapid. There is no reason to think that the evolution would not continue at that pace.

These Lighthouse 5 mm pictures are courtesy of Graham Andrews at CT.

Lighthouse’s attempt to reach for the untested technology created an opportunity for Barco. Chip-on-Board has had as many false starts as 3D cinema. It is both the obvious answer to the shortcomings of current and past LED displays and an unforgiving technology where manufacturers face issues relating to yields and optical variations that are a function of the different manufacturing methods of red and green/blue diodes. We are now actively watching various chip on board (COB), integrated matrix device (IMD), and various coated surface mount hybrid technologies compete to further expand the reach of the LED market.

The Alternative Displays

Blair Neal has a comprehensive article on this topic over on Medium.

“An artist has a large range of ways they can display their work. Cave walls gave way to canvas and paper as ways to create portals into another human’s imagination. Stained glass windows were early versions of combining light and imagery. Electronic displays are our next continuation of this same concept. A photon is emitted; it travels until it reflects off of or passes through a medium. That photon then passes into your eyeball and excites some specialized cells — when enough of these cells are excited, your brain turns these into what you perceive as an image.”

The previous article addressed creative LED displays but there are all sorts of creative displays and there are always technologies, creative and/or purely commercial, that are on the margins supported by companies that hope to take them mainstream.

The Alternatives – PRYSM

Companies such as Prysm [ [https://www.prysm.com](https://www.prysm.com) ] attempted to move to new semiconductor based display platforms. Prysm‘ s product was based on the logical assumption that blue laser diodes would become commodity items based on their use in consumer video products and that blue is an effective pump for phosphor conversion and that everyone had fond memories of CRTs and Plasma screens. But there were substantial hurdles in refining these screens to the point where they could effectively compete with LCD displays.

FORM – These displays were housed in metal boxes similar in many ways to those used in projection walls but the scanning laser system required a level surface to function. This fascinating exploded view from Edgewater shows just how different the Prysm product was from a projection cube even though the form fact looks similar.

The Alternatives – Mitsubishi

Mitsubishi showed a modular OLED tile but sadly appears to have given up on the technology. The odds of a modular OLED screen coming to market

FORM – I do not have any documentation on this and would very much appreciate adding any available documentation to the linked folder. I can presume based on other displays coming out of the Japan that the housing was a formed sheet metal box that contained the OLED modules along with a receiver board and a power supply of some kind.

The Alternatives – Shinoda Plasma Company

— INTERMISSION —

We now pause to allow the remaining plasma TV owners to tell us how much better plasma is than LCD. Larry Weber and Tsutae Shinoda are going to send you all flowers!

I recommend going out and getting some coffee. Maybe order a soufflé. It could be a while. And by “going out” I mean go get some snacks in your kitchen and maybe more your laptop to a new spot.

— END of INTERMISSION —

Tsutae Shinoda was a key individual in Fujitsu’s development of plasma display technology. There was a point where the apparent cost reductions in plasma display technology seemed sufficient to propel it into the lead but LCD technology drove further and faster and while not technically as good as plasma in many respects the cost advantage allowed LCD to dominate the consumer television market guaranteeing that plasma would never move beyond the margins. Panasonic, Pioneer, and Fujitsu all exited the market.

Here are two cool videos 1, 2

When Tsutae Shinoda started his own company, still closely aligned with Fujitsu, he focused on making large screen seamlessly tiled plasma displays using plasma tubes. The concept seemed to have a lot of merit and there were many demos including one at SID’s Display Week in 2013 . The screen was attractive because it was remarkably thin and capable of curving. But the display never did not roll out commercially.

FORM – This display is similar to the LG Wallpaper OLED product in some senses. The flexible PCB [FPCB] connection at the perimeter of the display indicates that there is some sort of source PCB that is required to drive the display. And that would attach to a display controller of some sort.

The Alternatives – Orion PDP

Orion PDP referred to their plasma screens as “infinitely expandable”. The displays featured an almost seamless glass front face and were, like all early plasma screens, somewhat delicate. They also clearly incorporated some sort of front optical display that expanded the image to mask the gaps betweeen displays at the expense of contrast.

FORM – The rear of the display was and unremarkable sheet metal box integrating all of the electronics. These displays faced a lot of the same alignment issues faced by narrow bezel LCD companies but these displays were glass to glass meaning the tolerances were even tighter.

The Alternatives – LG OLED

LG has a history in narrow bezel LCD but has recently done some excellent work with OLED as evident in their 2018 CES booth or a trip through Inchon Airport. While OLED cannot currently match the small bezel size of LCD products it does offer a superior black. The thin OLED panel also lends itself to many applications where LCD panels may be inappropriate. Most critically the LG panels can curve allowing for the creation of a fluid rolling canvas similar to the Shinoda Plasma application demos.

FORM – One interesting detail of the LG OLED video wall systems is the choice to separate the display panel from the control electronics and power supply entirely – as seen in the image above showing the display (upper left) and the control box (center bottom). I think this approach is partially a result of an incomplete vision for where OLED fits in the modular display space and it is partially a result of OLED being synonymous with thinness. At what point does it cease to be a display and become just another finishing material? In some ways this has more to do with the Barco MiPix than it has to do with the Barco Unisee.

 

Modular Display History: Part Twelve

Heat is a problem. It is a problem that impacts the working life of an LED package. It is a problem that impacts what color your screen is. When working on LED screens engineers will often just convert the display wattage directly into BTUs. The assumption being made is that an LED display is just a heater that happens to make light. There are a number of factors feeding into this. Heat from the AC to DC conversion, heat from the many resistors used in most LED screens, heat from the driver chips, heat from the LED dies themselves. It all adds up and if you want your display to perform well over an extended period of time then you need to manage heat.

When I say you can optimize for RESOLUTION or BRIGHTNESS but you have to pick one or the other this is what I mean and yet I acknowledge that all of this is constrained by where we are on the technology curve. We are constrained by affordability, reliability, and weight. A flip chip used in a microLED display is far better at dissipating heat than a larger LED die encapsulated in a DIP package. But then you aren’t trying to cram DIP packages together in the same way. Even in the case of a common cathode system there will be a choice between maximum brightness and maximum resolution. A time will come when we have excess brightness in the display at retina level pixel pitch for stadiums but then HDR and 8K cameras will continue to drive resolution.

We can throw this all out the door right now and build a display out of Jade Bird µLED modules each of which generates tens of thousands of Nits. At Display Week and elsewhere Jade Bird has shown displays capable of millions of nits so this is possible. These products are microdisplays aimed at the head mounted display and projection markets.

In this instance we can skip past the history of Jumbotrons, Astrovision, Starvision although it is worth noting that key elements of these displays were contained in sealed glass envelopes. The Philips Nitstar was LCD based and probably had a different system topology that was something like fluorescent lamp behind a color filter.

The tension between RESOLUTION or BRIGHTNESS is typical of outdoor displays. The displays need to be bright to compete with the Sun which is very bright as many have noted. Blair Neal wrote an article on why LED nits and LCD nits and projection are all different and this relates to why projectors and LCD displays are not so great in the sun.

[How to do video projection in full daylight – Blair Neal – Medium]

This might be a good time to point out something that we discussed when Blair was working on that article. That in LCD and projection the actual pixels have high fill factor. They take up a lot of the surface of the displays. This is a big part of why projection feels softer. But both LED and LCD are measured in nits so you can get a 2500 nit LCD and a 2500 nit LED screen. A nit is a measurement of surface brightness defined by one cadela per square meter. So to crank out 2500 nits an LCD is using almost the entire flat reflective surface of the display. But the emitting area of an LED display is much smaller. The reflective well in the middle of an LED package might be 1/3rd of the surface area of that surface mount component on the high side. But it could be 1/10th or 1/33rd of the overall pixel surface. If you just measure the size of the red, green, and blue LED dies it is much lower than that. And the rest of that surface is used to reject or trap ambient light to minimize reflection and improve contrast.

This is a good news/bad news thing. The good news is those plastic louvers and the gaps and holes help reduce glare and increase contrast. The bad news is that these parts also limit natural convection across the PCB and the LED packages. They trap the heat in to some degree. And metal shaders create a solar heat sink. Companies have played with perforating the shaders and using light pipes. This is part of a series of adaptations and compromises driven by the need for high brightness that relate to panel size, thermal performance, environmental protection, and viewing angle. For example large louvers help increase contrast but at the cost of viewing angle. A similar trade off was made with some DIP LED packages that had an asymmetrical output based on the shape of the reflector in the post and the encapsulated lens. With a fixed amount of luminous flux a decision was made that the vertical viewing angle as not as important and the horizontal viewing angle.

Another example is that many early LED screens needed dedicated HVAC. Not needing air conditioning was one of the benefits that Element Labs wanted to achieve with the Cobra panel. This was a case of eliminating a compromise that clients had come to accept as a competitive advantage.

We would typically look at the results of these decisions in terms of how they are manifested in the display stack but they show up everywhere in the system. One of the nice things about the LED clusters is that each one can be potted with a silicone resin but that cluster was still driven by a PCB that needed to be conformally coated and placed in a metal box. But the market has long ago moved away from LED clusters to larger more integrated matrices. While some of these decisions do impact the structure or form of the display most of these decisions show up in the LED display module where companies will try different louver and shader construction. Some have used two-shot injection molding to include black and transparent materials in a single part to better seal the front surface of the display. And almost all displays use some form of potting to try to minimize the possibility that any contamination or corrosion might occur in the PCB. Cruise ships and coastal cities often expose screens to salt in addition to water and so these environmental controls are critical if the screen is to operate for a reasonable amount of time.

Just the need for the potting and the need for the louvers pushes screen designers to have more space between LED packages. And it is possible to ignore this but you might end up with a screen where the contrast is not that good because the white reflective cups in the LED packages now make up too high a percentage of the overall screen. The point here is that if you switch to a high contrast LED package you drop perhaps 20% of your light output. Contrast and brightness are also often at odds.

I remember visiting Pilkington Glass in northern England and looking at their test facilities where they would take insulated windows past the point of structural failure but where they also had tests for salt and high humidity. All of the electronics in an outdoor display must be protected in harsh environments like cruise ships. But the thermal extremes in desert environments can be equally taxing. The power supplies and data distribution boards are vulnerable and a build up of heat will have a negative effect on the display.

One interesting lesson from the glass industry is that they eventually stopped trying to prevent water from penetrating the systems and they started focusing on making sure that they left vias for that water so that it would exit the system. As we get to wireless data transmission systems and panels that can achieve 10,000 nits at relatively low power perhaps the display industry will be able to shift the focus to simply managing the path of the water.

 

Modular Display History: Part Thirteen

The LED display business is changing. I mean this in a very specific way. This is not a vague arm waving “the LED display business is always changing” statement. I do not mean “the only thing that is constant is change”. I mean that what started with a Sony 55” television demo at CES almost a decade ago is now a wave of large highly-integrated companies pushing the limits of what displays can achieve with light emitting diodes. Samsung has become a very active part of the LED display market. LG is here. AUO is making some very good looking microLED panels (as R&D demos at Display Week and other tech shows – see also Lextar). And I also mean that companies in China like BOE are almost certainly going to be a factor in the LED display market in the coming years. If you are not familiar with BOE I would normally state confidently that you had seen an LCD panel made by BOE in the last week while traveling or walking around a city in an advertising or point of sale display but since most of us are stuck at home perhaps you have not seen a BOE display this week. To understand the scale of BOE you need to understand that they are one of the reasons that Samsung and LG are exiting the LCD panel market.

But BOE is not getting into the LED market. BOE is getting >back< into the LED market. And that is where our story begins with Michael Hao of Infiled explaining his professional journey in the LED display business. We exchanged some messages and emails and for the most part I am letting Michael tell the story with some small edits. He put a lot of information down here and I greatly appreciate it.

Michael Hao: In June of 2000 I joined BOE Shenzhen division which was established in 1999, co-founded with CNEDC (China National Electronic Devices Co., Ltd.) and dedicated to the LED display industry.

BOE was one of the early main players at the LED display industry in China, in the early 2000’s the other three key players are Leyard (prior to the joint venture with Barco), Lopu (in Nanjing), and QS-Tech (Xi’an). These four dominated the Chinese Led screen market at that time.

I worked for BOE for six years, moving from a hardware engineer to the R&D manager and then the chief engineer. In 2011, I developed a control system working with the Sony CX3281N driver chips, which was sophisticated for the time and even today it would not be out of date technology wise. It contains all the advanced elements which we are still used by today’s key integrated circuit suppliers, likewise the built in chips pulse width modulation, phase-locked loop (up to 80 Mhz internally), current gain control, and open/short circuit detection. Toshiba didn’t catch up, TI released couple of versions with no success, MBI took a long time to match the level of performance, but phase-locked loop and delay-locked loop are still missing due to the patented IP block by Silicon Core Technology.

BOE decided to focus on LCD industry supported by Chinese state and started to fade out from the other businesses including LED display since 2005.

In 2006, I moved to a private company, which I gave the English name, Sinolight. Prior to my joining it was called YJG, the Chinese name initials which make no sense to the oversea market.

At the time, Sinolight implemented individual 1in1 single color SMD LED, like the 0805 and 0603 chip type LED. So one pixel contained one RED package, one Green package, and one Blue LED package. The interesting thing is that the bin classification can be very tight for each color and the homogeneity of color and brightness were excellent by using this LED.

Meanwhile, single package allowed the dynamic pixels happen by the arrangement of the single LEDs as you (Matthew Ward) mentioned in the prior part of the articles, the virtual pixels.

Top type 3in1 LED was only available from the top brand like Nichia, Cree, Osram, Avago (Agilent Technology) and the cost made the LED screen a luxury item. Big Chinese LED encapsulation company like Nationstar drove the TOP 3in1 LED in 2010’s and the single package SMD LED quit the market whilst the funny thing is that the tiny package 3in1 led for tight pixel pitches like 1010, 0808, 0606 actually are utilizing the chip type package as the “old” technology.

Three years in Sinolight, I enjoyed the opportunity to meet with many oversea clients and industrial experts, to build products for them as well. Including the first version of ICT inspireLED M25M, white version 25mm mesh panels mainly used for BMW booth in motor shows.

In 2009, due to different viewpoints on international business, I left Sinolight and founded Infiled with my team. It was unfortunate that Sinolight went bankrupt in 2011, the same year as JDL, another top ten Chinese LED display manufacturer. These bankruptcies gave a sign to the booming industry that professional-operation-oriented management mode is necessary for all LED manufactures already. The industry has turned to the next phrase. The era when everyone that participated can earn has gone.

The industry is quite mature nowadays and it is getting harder and harder to find inspiration, as people follow each other, like the other industries doing the same thing. Eventually the competition will be driven by quality control (at all aspects) and cost control.

I would like to admit that the great “invention” of the last decade was NPP (Narrow Pixel Pitch) LED screen from Leyard, it opened and created a new market for our industry, it benefited every player in it including the entire supply chain. In person, I respect it very much whilst I disagreed it like most of the others in 2009 when we first saw the 1.9mm screen that Leyard showed in LEDChina show.

Today, a big player like Samsung is pushing their own micro / mini LED technology and racing in our industry. Micro / mini LED could be the next game-changing factor in this decade for indoor LED or display wall.

The biggest challenge or pain point for LED display, I would say is the homogeneity for perfect screen. Homogeneity for the black, homogeneity for single colors, and for the most tough white color by RGB. In rental and staging vertical, it is a sweet dream that different batches LED can match in one screen from different manufacturing dates and batches. The best calibration system still can NOT make it works in acceptable level today even with the LED chips already pre-selected in bins. Black surface is the king for contrast, the homogeneity for the mask(shaders), coating, PCB, glaring level need to be all settled perfectly to avoid the tiles visible effects, especially under strong ambient light.

Michael ended this section noting that “With 20 years of experience in the industry I am still learning many new and surprising things about this technology every day.” As Michael noted he moved from Sinolight to Infiled in 2009. Given that Michael left Sinolight to start Infiled with a team of people there is some continuity between Sinolight products and early Infiled products.

Michael highlights all the key items that companies in the LED industry are focused on right now. Resolution is important but integrating microLED and miniLED requires a process engineering driven culture. And as we focus on processing engineering it is important to understand that homogeneity is critical not just within a single LED tile or a single production run but within the total lifetime production of product at a factory or across multiple factories.

Handing things back over to Michael to look at the early days of product development at Infiled.

Michael Hao: The first product we actually built was ST-18, a 576 mm x 576 mm mesh platform with clickable LED strips which made with SMD5050 and sit in an aluminum strip housing with Parylene coating [Editor Note – Parylene is a thin transparent coating that can be used as a conformal vapor barrier on electronics. Sometimes it does not play well with UV light]. We could be the first manufacturer to implement Parylene coating onto LED outdoor display panels.

ST-18 was built in 2009 in the year when Infiled founded. In general, it was an ODM product for Visualed, Denmark, directed by Anders Prehn. It was quite successful in Europe, ICT Germany, Rentall Netherlands and other countries like Denmark, Russia … In America, it was exclusively distributed by Theatrixx Technology, a Canadian company. The other part of the world, South Africa, Brazil, Australia and South-east Asia, many companies invested the same product.

The pictures of the ST-18 is as follows. You can see the triangle “wedge” parts which are for changing the angle, and these triangle blocks can be stored inside the frame when the screen curvature doesn’t need them.

The sales were interrupted by the one big batch LED failure and Infiled spent half year of time to recall the whole batch spreading globally. We still get sales after the recall but the lost half year did impact the success of the product.

The image above is fron ST-18 job in Canada. The image below is from an ST-18 job in Indonesia.

In 2010, for mesh product, we built our own platform. We called it C series. The picture that follows is the C14, a 14 mm product.

It continued the 576x576mm panel size, the main frame was still with aluminum profile with CNC metal parts for the kingpins (which is retractable) and the adjustable curve coupler, which we called it VAC (Variable Angling Coupler). The VAC was a built-in -10 deg to +10 deg, 5 stops integrator curving and locking system, it was the very beginning VAC mechanism invention and many of the followers taken the conception just made with changing shape or stronger part.

Instead of expensive aluminum single strips, we have updated it to a PCB cut-out module base mesh tiles, it saved the cost significantly and increased the manufacturing efficiency dramatically as well.

Again parylene coating was implemented and it saved the necessary spacing for silicone coating, which can make the mesh transparency ratio as big as possible. Beside 14mm, we also built 9mm on the C platform.

In 2011, Pete Daniel and Mitch D. Kaplan visited Infiled with Graham Burgess, they loved our C series, all the concept except the tile dimension. We quickly made a decision to develop the 500×500 panels with the exact same as C series.

Three months later, we started to deliver MC7, MC15, then followed MK7, MK10 (MK series were with straight frame, no curve features). The products were quite successful as digiLED products in USA.

When I decided in 2009 to establish a company to follow our own vision to make products and businesses, I already got something in mind to develop a product with our own DNA, a product can be used both for rental and fixed installation, a platform can be good for both indoor and outdoor applications. The product/platform need to be standardized and with great productivity to replace the conventional metal box based LED cabinet products.

Thanks to my team’s great efficient R&D work, elapsed about one year time, the remarkable Infiled L series (Legend) was launched to the market.

Comparing to the metal-box LED panels, the L series contained overwhelming advantages in terms of reliability, integrity, weight, thickness, accuracy, serviceability, power saving and noise controlling.

The L series is in a 640x720mm form factor platform, 8:9 ratio to consider both 16:9 and 4:3 aspect ratio applications, pixel range covering from 4mm indoor up to 20mm outdoor. It is a modular design composing three elements which are 6 LED display modules, one frame, one PDU. Four captive screws for each LED Display Module and only one big captive screw for the PDU, tool-less service design. With the built-in frame kingpin and fast locks system, the panels can be used as hanging or stacking mode. 17kg per panel and 37kg / m2 versus 60-70kg / m2 of the metal box panels. Passive cooling design without fans features a silence screen.

All three elements of L series are IP rated respectively and this makes the product so much easier for the users to install and maintain the screen in the field.

L series was quickly accepted by the market, and the first big project was for Jacky Cheung (Hong Kong super star) 1/2 century world tour (2010/2011). Picture follows, operated by AV Promotions HK.

The L series has been recognized as the icon of Infiled and made Infiled known by the industry. Although more lighter weight die casting products came into the rental market, L series was still very strong in the permanent installation sector due to the modular design and flexibility to implement the product. L series is still active and remains in the top sale list of the Infiled portfolio, with the latest industry technology updated.

In 2013, Infiled launched our first platform for NPP, the S series, down to 1.8mm.

With the retractable footers and side blades, it introduced the industry first built-in protecting mechanism system for tight pixel pitch LED product to release the pain points of the fragility of the NPP product.

ICT did a fabulous installation project with S2.4 for the headquarter of Volkswagen in 2016, 110m2, 8K curve screen. Picture follows

Like the computer industry follows Moore’s law, our industry has been keeping evolving rapidly since it was born. No matter what you have achieved it is all in the past. To stay relevant innovation needs to be continued non-stop …

One of the nice things about our industry is that we have not had Moore’s Law, but we do have Haitz’s law.

“Named after Roland Haitz, a now-retired scientist from Agilent Technologies, the law forecasts that every 10 years the amount of light generated by an LED increases by a factor of 20, while the cost per lumen (unit of useful light emitted) falls by a factor of 10.” [Haitz’s law | Nature Photonics]

This was put forward at show called Strategies in Light which is where you could find Tony Van de Ven and many other people around 2000. I think I visited the show in 2000 at that hotel on the 101 in Burlingame but only to poke around and see Tony.

Haitz’s law is sort of like a guarantee that we will have excess luminous flux for some applications. Haitz’s law tells us that light bulbs may become too cheap to manufacture. But Moore’s law is about bulk computing where the CPU (or SOC) can be the dominant component in the bill of materials. And to a degree Haitz’s law has been much more relevant to commercial lighting which is a bit more like this when they look at light engines. Where Haitz’s law says that we will get more lumens at a better price the LED display industry basically stops caring once the mechanical system exceeds 50% of the bill of materials cost for a given pixel pitch. Basically wherever that is we can draw a line between the past and the present. The process driven approach of microLED might make Haitz’s very relevant to the LED display industry.

NOTE: The nice thing about doing most of the writing myself has been that I do not need many rules. Michael has done much of the heavy lifting this week and that made me consider what works within these articles and what does not work. I have tried to avoid discussing current products in this series except to point out similarities or to create context for longer term trends. I try to use 2016 as a cut-off for a variety of reasons. First—The series is about the core technology and historic trends and I want to avoid sales and marketing discussions. Second—2016 feels like the year by which a lot of major changes had been codified. There are certainly new products but they do not need to be covered here.

 

Modular Display History: Part Fourteen

Flexible /ˈfleksəb(ə)l / adjective

• It bends. To bend. Bendy. Bendable. Floppy. Twisty. Curvy. Swooping. Droopy.

What does “flexible display” mean? Did anyone ever ask for a flexible CRT or a flexible Jumbotron? If not was it because they were afraid of being laughed out of the room? Do people assume heavy things are inherently not flexible? What about other technologies? It is a fact that an LCD panel is flexible right up until it isn’t. LG has made some very interesting flexible OLED products but they are wisely not selling the roll up version delivered in a tube so customers can just velcro it to the wall. Have you ever checked to see if any of the walls of your house are plumb? Do people know that the large format LG OLED displays used in televisions and the smaller OLED panels in phones are built on a completely different display stack?

If you have to bend all the fibers to get them into the display is the display flexible? How many people mean “stretchable” when they say “flexible”? I have a lot of questions.

I am going to divide flexible displays into the following categories: Bendable, Segmented, Fabrics (soft meshes), and Mechanical. There are some gaps here that I will address later in the article. It is also worth noting that some of these break my earlier categorization of displays into boxes, space frames, and shells (monocoque) and this is because I excluded tensioned displays.

BENDABLE – This is a solid two-dimensional plane that can be deformed to create 2D and some limited 3D curves. A thin FR4 based PCB would meet this criteria as would variable flexible PCB options.

SEGMENTED – This is a single unit formed of nominally uniform subsections that are held together by an adjustable frame or shell that allows for the curvature of the segments to be controlled and fixed at a desired point.

FABRICS – These can be fabric based meshes or nets. The key factor will be that the connection from pixel to pixel or module to module can move independently from the connections to other points in the array such that the display can be “draped” in a non-2D manner.

MECHANICAL – A very large screen that can change its shape might be considered flexible in some manner. Flexible joints that allow a screen to change the physical relationships between display modules for example.

We can add to this classification a timeline that indicates that designers and tinkerers wanted flexible displays almost as soon as companies even started imagining full color LED video displays. This statement from 1993 “Further, the color display device according to the present invention includes a color display device having a display portion which can be rolled” and through the use of “three light emission diodes of three colors, for example, red, yellowish green, and blue”. The interest in less rigid displays also drives this statement about LCD panels from 1994 “With the technology thus limited, it is a general aim of the present invention to provide an electronic display which is readily configured in a curved or flexible (hereinafter non-planar) configuration, and is thus suitable for applications not readily served by the current flat panel liquid crystal displays.”

I first encountered the illustration on the right below (Zhang) when I was researching a patent that Element Labs was considering filing in March of 2006.

The appearance of full color LED displays was followed almost immediately by simple mesh screens such as the LEC screen in Japan and the initial fabric design concepts for the backdrop of the U2 PopMart tour happened right a the beginning of the modern LED display industry. This rapid iteration was driven by the accessibility of the modular components that go together to make a screen. Once there are “intelligent LED clusters” you could make strings of LED pixels meaning that the design and functionality of the electronics and the mechanical system can be separated in such a way that one set of electronics (and string of LEDs) could be integrated into a variety of different configurations. This is a critical point that ties into several of the earlier articles and was the focus of Modular History Part Ten. An LED display is an arbitrary arrangement of components to the degree that the driver is separate from the light emitting components is separate from the mechanical and packaging systems. So in theory I could take 192 LED dice (64 x r, g, b ) and some driver components and make a nice animation where we bounce through a series of assembled and exploded views where each finished design is immediately stripped back out to its raw components and then reconstituted as a completed different screen. As Michael Hao noted last week, you can put the red, green, and blue LED dies in three discrete LED packages or you can integrate all three colors into a single package. A wide range of designs were possible with off the shelf components and if you are willing to move beyond what is available off the shelf and you have a modest budget you could get custom LED packages or custom drivers and you can make something new at a fraction of the cost of other display systems. This is not possible with an LCD display because LCD display production is driven by process engineering costs and the optimization of a flow of display glass through a fab. An LCD display manufacturer might want guarantee 100,000 units a month volume when they look at producing a custom panel. At lower volume the costs are eye watering. OLED displays are the same. Making a custom CRT was probably just as bad. This massive variation in display topology is unique to LED.

BENDABLE – I like the phrasing in the quote above. A bendable display delivers a “non-planar” screen surface. This is possible by altering the materials used or by simply making the materials so thin that they can be bent to a certain degree.This is what is happening with large format flexible OLED and also what happens when you try an pick up any modern LCD glass over about 40″ diagonal. The glass is so thin that if you lift one corner the panel will become … non-planar. The Shinoda Plasma tubes should probably be categorized as a bendable display in spite of the fact that the each display was composed of many tubes. And there is another non-planar plasma display option using plasma spheres. This work was performed by Carol Wedding at Imaging Systems Technology.

In the case of LED display modules this can be achieved by using a very thin standard fiberglass (FR4) PCB or by using polyimide or another flexible PCB material. Nanolumens obviously factor into any discussion of this particularly because their particular journey started with a ground up rethink of how to drive an LED display. And while they eventually adopted a more traditional LED display topology it is the belief in the initial concept that drove their commitment to flexibility (link to photo).

 

Another early advocate of flexible LED tiles was Digiled who introduced the digiFLEX product in 2008. The digiFLEX module integrated a silicone rear housing with magnetic physical connections that work with any ferrous material an integrator might use. This means a laser cut sheet metal armature can be applied to a form allowing for a large continuous surface for the magnets. This can be viewed, from a certain angle, as an adaptation of the MiPix clip system.

You can see in both displays above the ability to deform off axis from the orientation of the display matrix which is interesting but limited by the need to join the edges of modules and the inability of these products to offer a true 3D curve without the use of trapezoidal modules.

SEGMENTED – A segmented display is composed of a series of LED modules that are connected to a structure that maintains the physical relationship between the modules as the curvature of the frame is adjusted. The are multiple ways to do this but I think the Winvision panel below is a good example.

It is easy to see the functional blocks of this frame. The low profile strips connected to a flexible lateral rib that can be tensioned by adjusting the arm. The degree of the adjustment is clearly visible in the center spine.

This “family” of flexible displays can extend into lower resolution displays like the ROE Linx, Revolution Display FlexMesh (VER), and other earlier displays. It is possible within this definition to extend the term Segmented to any assembly composed of multiple modules connected in an adjustable linkage. By this definition an Element Labs Stealth panel would not be a Segmented display but a touring rig of Element Labs Stealth panels shipped on a set cart or case and connected to a curved header would be a Segmented display. This inconsistency is because I am making all of this up as I go. Happy to hear your rules in the comments.

The LED segments in the display can be scaled to deliver a full display (rather than a mesh) and depending on the rigidity of the segments the finished display could be segmented or curved. In the Gtek display below you can see clear vertical lines dividing the segments. The picture of the GS2.9TC on the left shows the edge of the PCB.

FABRICS – A Fabric display will almost always be composed of LED strings because as noted earlier the electrical requirements and the mechanical design may not … mesh. [Thank you. You read this far and I dropped that on you.] The demo screen for PopMart is a good example. If you can drape the screen across a car and the result is even vaguely car shaped then it is probably a fabric.The Soft-LED product from Main Light is a good example. Color Kinetics light strings integrated into a drape.

Element Labs introduced a product called Helix H75, that was developed by a small UK company. H75 was a cargo net like mesh. Each module had four pixels but the intra-module connections were all flexible.

The one area of flexibility that we do not cover above is the flexibility of LED screens and pixelated LED tape. The question I would ask mirrors the contraction in the Stealth panels. A single panel is not flexible but when used in an array connected by flexible hinges the product could be considered as a Segmented flexible display. If you took a single piece of pixelated Cotco LED tape is that a flexible video display? What if you integrate multiple pieces of LED string into a backing material like the Main Light Soft-LED product?

The illustration below relates to this video – Secret Video

The nice thing about LED string and LED tape is that you can meet a lot of unusual design requirements by bending LED string or LED tape into all types of contorted arrangements.

I think both of the projects above were handled by XL Video. The Beastie Boys project on the left always reminded me of an Alexander Calder mobile although I have no idea if that was the intent [Additional information]. If you want more of the same you can check out the Marco Borsato show here.

MECHANICAL SCREENS – A screen where the flexibility is defined by the ability to vary the position of one module relative to other modules in the system.

I remember Tait and Nocturne making a Venetian blind screen for a tour. The LAADtech screen is conceptually if not mechanically similar. The link to the PDF document is well worth following in spite of the streak of “the condescension of hindsight” that is apparent in a document from 2013 covering a screen designed in 2005. [Yes, he beats up on Stealth a bit]

And the Barco FLX was conceived of as a much more ambitious hybrid of string and structure. The FLX 24 was at the core of the U2 360 screen. The one ring to bind them all. A flexible and modular string product designed to give designers total freedom.

It is obvious that you can approach “Flexibility” from a number of different angles. I have laid out a few but there is something consistent here which is that the goals of the designer and the requirements of the application drive the design just the same as any creative display. There is an approach that says “I can do everything with LED tape” and a reality that a more carefully considered design will yield a more robust system.

At their essence, outdoor LED signs are simply signs that include a display, or “message center” made up of light emitting diodes (LEDs) to form text, graphics, or animations as a marketing tool. Although it may seem like a no-brainer, to answer the question “What is an outdoor programmable LED sign?” in detail, but it is not so simple. A general understanding of the history, technology, and variables in the outdoor LED sign industry are necessary to be able to understand the whole answer to this question. Armed with this knowledge you can find yourself in the driver’s seat if you are seeking to plan a sign project of your own. The following points are intended to describe in detail each of the most important variables to consider when defining what your outdoor programmable LED sign should, or could have depending on your specific needs and preferences.

#1: The History of LED Signs:

Light emitting diodes have been around for a very long time. A Russian scientist named Oleg Losev reported the first discovery and creation of light emitting diode technology in 1927. However, there was no significant application of the technology for decades until in 1961 James R. Baird and Gary Pittman of Texas Instruments in Texas were able to demonstrate that LED technology could be made into a commercial product. In 1963, Texas Instruments announced the commercial LED product, but the light emitted was not readily visible. During this same time period, General Electric was running its own experiments resulting in the announcement of the first LED capable of producing a visible light spectrum in the December of 1962 issue of Applied Physics. By 1972 General Electric improved the brightness of their LED tenfold.

Cost:

In the 1960s a single LED diode capable of emitting visible light cost $200 per unit. These diodes were only used in medical equipment and other high technology devices requiring little to no heat output with reliable light emission. By the 1970s LEDs were used in calculators, radios, TVs and other appliances thanks to Hewlett Packard’s work in making the technology more affordable and practical for commercial uses.

The First LED display:

The work at Hewlett Packard that made LEDs more practical for commercial applications was headed by Mohamed M. Atalla in collaboration with Monsanto to produce the first programmable LED display at HP. It was considered a revolution in technology at the time as the world’s first intelligent display. Atalla’s methods from this time period are still used in LED production systems to this day. The diodes in these devices were still quite dim, and red was the only color until a bright blue was obtained through increased innovation in the chemistry of semiconductor technology as it pertains to light production. Diodes were covered by a colored lens to produce a specific unchanging color. Today, LEDs are produced in Red, Green, Blue, or all three in one diode in the case of SMDs or Surface Mount Diodes which are used in today’s outdoor LED signs with definitions of 10mm or lower. This is required in order to fit the diodes closer together and thus create a higher definition image.

#2: The Main Components of Outdoor LED Signs

All outdoor programmable LED signs have the same basic components at their core. Other features, components, and the like can be added. The additional components and/or features can often be used to cloud one’s understanding of an LED sign’s value. So, it is a great idea to understand the basics that will allow you to ask the hard questions.

The Diode:

All outdoor LED signs have diodes. But not all diodes are made the same. An important quality indicator of a diode is the brightness level rating. As diodes are produced they are dropped into “bins” to sort them by their brightness quality. This is the best way to tell diode quality, as long as the same amount of electricity is provided to the diodes being tested. The problem in today’s outdoor LED sign industry is that many manufacturers use cheaper diodes with lower brightness ratings to save money, which is fine in and of itself. However, these companies then configure the power supplies in their signs to push extra electricity to the diodes making them brighter for the short term. The problem with this method is that it forces the diodes to degrade much quicker than they would have under normal electrical conditions. So, if you have a sign that is claiming 10,000 NIT brightness, you may want to dig deeper. Diode manufacturers producing 10,000 NIT diodes are proud of their product and the manufacturers that spend the premium price to use these diodes are equally proud and willing to disclose where their diodes are coming from. Some examples are Nichia, Cree, Osram, Lumileds and others.

The Cabinet:

Programmable outdoor LED signs are always going to need to mount to some sort of support structure that houses the internal components and provide a safe system for the LED modules to mount to. Low quality cabinets are made from steel and allow for water to leak in. Steel rusts, so it is inevitable that water infiltration will be a problem for these signs. Most moderate to high quality manufacturers are using aluminum cabinets to avoid problems related to oxidation. These cabinets should be painted with sign grade paints like Matthes PAint, or Akzo Nobel paints. Some cabinets are powder coated as well.

Power Supplies:

Power supplies accompany just about every electrical appliance or device in operation today. The purpose of a power supply at its essence is to receive power from the raw source circuit and condition that current to a specific configuration to serve the purposes of the destination where the power is actually sent from the power supply itself. Outdoor LED signs have many types of power supplies, but they should all be judged by their ability to deter the two most common enemies of LED signs; heat and humidity. Overheating and water infiltration can cause degradation and failure in electronic components. IP Ratings are often used to measure the ability of a component to suppress or prohibit water infiltration. Look for verified IP67 or IP68 ratings. Independent lab certifications like UL, MET, or ETL among others are useful to verify if a component is going to withstand the heat it will encounter outside in the elements. (see: https://guthmansigns.com/blog/ul-vs-etl-vs-met-listing/)

Wiring:

Of course, electrical components in an outdoor LED sign will need to be connected in some way, and these methods are extremely important to consider and understand. Lower cost options include ribbon cables of varying sizes and specifications. Ribbon cables have many points of contact per cable (over 30 in some cases) creating increased probability of failure. Basically, the rule is that the more points of contact there are, the higher the probability that a failure will occur. Many factories of medium to high quality use more modern connectors with anchoring systems that keep cables from wiggling loose.

Cooling Technology:

Since heat is such a detriment to the longevity of LED signs, it is important to understand the ways manufacturers try to cool their displays. Traditionally, cooling fans have been employed. With these designs, fans are mounted inside the sign cabinets to pull air from one side of the sign and push air out the opposite side, to keep cool air circulating over the internal components. These systems work well, as long as there is enough space between the cabinets so hot air isn’t continually re-circulated back inside the same cabinet.

Another method is the heat sink. These methods are denominated as passive cooling systems since they don’t have any moving parts. They are simply metal ridges protruding from where heat is generated in order to allow heat to dissipate naturally. Again, space is extremely important to allow these signs to stay cool and last their full life expectancy.

Potting/Conformal Coating:

LED sign modules are made by mounting diodes to circuit boards and mounting these to varying styles of plastic squares or rectangles that, when placed together and connected to one another, can operate as a full display. The modules are where water infiltration is most dangerous because of the fragile connections that are included on circuit boards and diodes. Lesser quality signs will have no coating at all and the circuit boards often fail quickly for this reason. Medium to high quality signs will have conformal coating (a spray on silicone gel) or potting (poured on silicone) to completely seal the components from water infiltration. Potting is generally much better than conformal coating due to the thickness and robust adhesion it allows for.

#3: Diode Color:

Another important quality indicator of an outdoor LED sign is color. Each diode, whether Red, Green, or Blue, has its own quality and brightness rating. Red diodes are generally the least expensive, and Blue is the most expensive for most circumstances, so a low quality sign manufacturer will often use high quality Red diodes or Green diodes perhaps, but will skimp on the Blue diodes. The result is visible to the passer-by if you look close enough. In specific, pay attention to the whites in the LED display image. If the “white” areas look pink or green in hue, you can be sure the sign is being pushed or “over-driven” with electricity and the other diodes have degraded faster.

#4: Software

In the LED sign industry, control software packages can vary widely. It is an area where many consumers do not pay much attention, and often regret that dearly later on. Some LED signs include very simple software that requires a dedicated laptop supplied by the manufacturer and the sign cannot be controlled otherwise. Others employ software packages that must be downloaded to a local computer tied to the outdoor LED sign by wireless antennas on site. Still other software packages are cloud based, allowing the sign to be controlled from anywhere in the world with an internet connection, including via smart phones, for example. It is essential to understand exactly how you will interact with the sign, thus requesting a demo of the sign software prior to purchase is advisable. Be sure to note whether or not a standard content package is made available in the software, or if custom content is available for order through the software. Note exactly how you will need to manipulate images or animations etc to upload them to the sign as these processes can vary widely in complexity.

#5: Communication

Any LED sign will need to connect to a computer to receive the playlist you want shown on the sign. This communication can happen in a variety of ways. The most modern, seamless, and reliable method of communication is via cellular modem. Many factories now offer cellular modems with data plans included so that once the sign is installed, it connects immediately, allowing users to program their outdoor LED signs immediately. Other solutions employ short range wireless antennas with one antenna installed on the sign itself and its pair installed to the building on site. The antenna mounted to the building then needs to be connected via ethernet cable to the router inside the building for this method to work correctly. This requires a direct line of sight and has a distance limitation of anywhere from 300-1,500 feet depending on the provider. Finally, LED signs can be connected with hard wire cat ⅚ cable (the same as your ethernet cable connected to your router in your home or business). Ask yourself which would be best for your circumstance, but if you can manage the $1,200-$1,500 cost increase to add cellular modem, it is often well worth it.