The LED videowall rat race
Paul Milligan finds surging demand for LED videowalls that are dropping in cost and pixel pitch.
But, how low either parameter can go, depends on factors sometimes out of product manufacturers’ control.
There is little doubt that LED videowalls are soaring in popularity right now.
Alongside wireless presentation systems it is the most talked about product in the pro AV market across EMEA. The market used to consist of very basic 20mm pixel pitch tiles, which only interested a small group of clients in high profile locations (Las Vegas, New York, Dubai and London, for example). Of those wanting a high resolution product (what was sub-10mm pixel pitch, and is now 3 or 4mm) it was a product only affordable for those with deepest pockets in the US, the Middle East and parts of Western Europe. A combination of rapidly improving technology and falling prices has seen it installed more frequently and in a far wider range of applications that ever before, and the product has reached mass acceptance.
Data from Futuresource shows the narrow pixel pitch (NPP) LED market (defined as 3mm pixel pitch or less) was worth $678 (€617m) last year, which was three times both the volume and value reported in 2014. The data not only backs up the rapid ascent of the LED videowall in recent years, but predicts this will be a continuing pattern for years to come. This year NPP LED tiles will make up 19% of the total videowall
market, with LCD narrow bezel panels making up the majority with 64% (rear projection videowalls make up the rest of the market with 16%). By 2020 the gap between LCD and LED will close dramatically, with LCD marginally ahead with 48% of the market and LED just behind with 44%. Given the low prices of LCD panels out there in the market, this is quite some shift we are seeing.
With regards to the technology inside the LED tiles, all the major advancements have come in one area: resolution. In the last five years pixel pitches have fallen from 10mm to 6mm to 4mm. And in the last 18 months that has sped up, as Koen Werbrouck, product manager, Barco demonstrates: “Barco released a 3.5mm product in 2005, then it took five years to get to 2.5mm, when Leyard introduced a model in 2010. Then it took another three years to get to 1.9mm and 1.6mm. Now we are in a yearly pattern and have moved from 1.2mm to 0.9mm.”
With greater resolution comes an increase in cost and fragility, but at the moment it seems to be a contest, Werbrouck dubs it a ‘rat race’, to see who can win the ultimate goal of getting to 0.1mm. As we look to the future of LED tile technology is 0.1mm a realistic possibility or just an unnecessary dream of a marketing team? “Is there a need to go to 0.1mm? I’m not sure. We also don’t have the physics to do it. The size of the LED diodes is not something we control. Going to 0.1mm means the LEDs will be 0.05mm, which is not reachable for the moment, and also can’t get the brightness we want at the moment. Is there any demand in the market for it? Because your eye can’t see it a few centimetres away, so the limit is the eye. Is there a need to go further? I’m not sure,” says Dominique Denis, LED market development manager, Christie EMEA.
He also hinted at a possible divergence and end game other manufacturers were looking at moving toward. “We are focused on sectors like control rooms, but some of our competitors are targeting the mass market of television. It will take years, but their plan is to replace your LCD or OLED tv with LED.”
According to Gary Feather, CTO at Nanolumens, LED pixel pitches will be driven by need, advantage cost and technology. “Current LCD and OLED TVs have a pixel pitch at 0.35mm and 0.7mm. I expect based upon size and viewing distance, discrete LED solutions where tiling is required will not have a need to exceed 0.8mm anytime in the next five years for commercial applications."
What reasons does he give for this prediction? “The eye limitation is based upon the fovea (the centre of the eye’s sharpest vision and the location of most colour perception) and the viewing distance. The specification for best viewing distance (when you cannot see pixels anymore) is 1000 to 2000 times the pixel pitch. TV viewing is set at 3x the picture height for HD, which for a 60-in TV is 30 inches and therefore about 90 inches away, or 7-8 feet. UHD is half that distance.” The consensus among all the vendors we spoke to was that the limit of the eye would be the limit of LED pixel pitch, with a figure of around 0.6mm marked as the eventual end goal.
“The viewing point of 0.1mm is really for screens for mobile phones, but even then there are better technologies than LED to do that,” adds Werbrouck. As highlighted above by Feather, money is also a factor slowing the advancement of LED, and will see this product segment move in slow rather than big steps.
“The price will limit development, it’s getting lower and lower every year. 6mm cost €4,000 per sq m 10 years ago, now it’s €3,000. If you look at the same curve, it will be affordable in three years, but for now it’s high,” says Denis.
Market forces, especially in technology, are hard to ignore it seems. “In our opinion the limit will be defined by the market and the demand. If customers need less than 100-in they will choose a flat panel display, if they need more the advantage lies with LED,” says Kageyasu Sako, senior manager, product planning, Sony.
There is another reason for this single-minded focus on resolution suggests Werbrouck; “Some companies only focus on LED, so they want this technology to compete with rear projection or LCD panels, where the resolution is much smaller. We know people are doing research into chip on-board and microLED but we don’t feel these technologies are ready for mass production. It’s a market that’s moving fast, but it will come to a point where it needs to stabilise, and new technologies need to be found to really go to the small pixel pitches.”
As mentioned before, the lower the pixel pitch the more brittle the tiles become, leading some buyers to be wary of sub-3mm products. Is there a future when even 1mm or 2mm tiles are robust enough for the most demanding of pro AV applications such as rental and staging? The market is sceptical. “Up to 2.5mm pixel pitch the diode is 2x2mm, so the soldering on LED tiles is very strong, below that it is very fragile. It’s very hard to move to 1.6mm or 1.9mm without any damage being caused,” says Denis.
While others believe it will be overcome, but it’s going to take time. “There are different approaches to tighter pixel pitches that range from SMD RGB LED to COB and finally to uLED. Each has great value at particular pitch and size; and each offers its particular advantage for rework, yield, durability, cost and infrastructure,” says Feather.
When you look at other display technologies, advancements have come in the form of touch capabilities, advanced audio options, gesture control, or facial recognition. Will we see any of these in future LED products? It seems unlikely, except for clients with very niche requirements. The cause? Physics, as Werbrouck explains. “Everything is possible, and we do get requests for touch systems, but it’s mainly the viewing distance that’s the barrier. If you have a 1.6mm LED videowall, you will have a viewing distance of 2-3 metres from the screen, which means you can’t use it in combination with touch.”
The same reasoning applies to gesture control or facial recognition, to view it well you need to be a few metres away, which makes those actions difficult. Another block to gesture control, audio or facial/gender recognition systems is the modularity of LED tiles. They are more often than not used in combinations of 2x2 or 2x3 etc so the only way to get a camera or speakers is to attach it behind the tiles or to the outside frame or the very top, which can ether ruin the aesthetics or may not be possible if the videowall is housed inside a wooden or plastic frame which has been designed to fit exact square edges.
If you have a videowall you are going to need something to drive the content, and that something is a video processor. More often than not each videowall manufacturer will have its own supplementary video processor product too, Christie has Spyder, Barco has TransForm, eyevis has Netpix. But is there the possibility we could see LED offerings built with more intelligence inside each tile so integrators and consultants wouldn’t need a separate processor?
Again, it seems unlikely. “At the moment all of the processing is outside, if you put it inside, the way you address all the signals will have to change dramatically,” says Denis. “With more complex electronics inside, this will increase the cost, because you will have to duplicate the intelligence inside each tile. With a wall of 100 tiles, instead of having one intelligent processor at the bottom of the screen you will have 100 boards inside providing the intelligence, which will cost more.
There will have to be a huge decrease in the price of the intelligence you will put in the board to be able to spread it everywhere.”
Apart from perhaps Silicon Core, the energy efficient properties of LED tiles is a subject often sidelined. Could we see any advancements here? Sadly, it seems the opposite is happening. “Our experience is that energy efficiency has gone down over the years,” says Werbrouck. “If you look to the LEDs we were using five or ten years ago they were much more efficient than what we see today, and I would put that down to the pixel pitch ‘rat race’.” How have we got to a place where this is acceptable? “It is very rare to choose an LED tile over a competitor on energy efficiency, they ask for brightness or colours or video rendering first. For most of the people who can afford to have an LED videowall in their lobby the electricity bill isn’t their main concern,” says Denis.
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