Walk into one of the Live! sports restaurants/bars operated by The Cordish Companies in major US cities and prepare to have your home high-definition (HD) TV experienced ruined — even if you have a 4k TV and content. Four of these restaurants located in Atlanta, GA; Arlington, TX; Philadelphia, PA; and St. Louis, MO feature giant, self-emissive or direct-view video displays that make you feel like you are in the game (Fig. 1). The brightness and contrast ratio are amazing. It would cost you near $1 million to get this experience in your home even in a much smaller size such as the wall of your living room. Still, LED manufacturers and display makers expect to deliver such an experience to mainstream consumers as mini and micro LED technology matures and the solid-state lighting (SSL) industry hurdles manufacturing roadblocks. This direct-view display sector is an application starting to consume an enormous amount of LED epitaxial real estate.
We will get to the present and future of self-emissive LED displays quickly. But first let’s take a brief look back. Self-emissive displays are widely deployed outdoors in major sports venues, on building facades in major metropolitan areas such as Times Square or any large city in China, and even in digital billboards and signs. LED is the only choice in such applications because LEDs can generate enough light output to allow viewing of the display in sunlight. Such outdoor displays aren’t cheap but are located in venues that can afford the technology. We once covered outdoor LED displays on a regular basis before the technology became commonplace. One memorable project was at a NASCAR racetrack back in 2011.
Such large outdoor displays have relatively larger spacing between pixels — a characteristic known as pitch. Outdoor displays, especially on building façades, might have pitch measured in inches or at least tens of millimeters, because the viewer is typically located far from the display. And pixel pitch drives cost in self-emissive LED displays, as we will discuss later. Some of these outdoor displays are constructed using strings or meshes with RGB (red, green, and blue) LEDs mounted in some sort of plastic puck forming each pixel. The HD-quality displays, such as those found in major indoor and outdoor sports venues, use rectangular or square panels with RGB LEDs mounted on a planar substrate or printed-circuit board (PCB). The pitch, especially in outdoor venues such as football stadiums, is still significantly larger than the emerging indoor displays we will focus on here. (See our sidebar below for a comparison on the video output of these two types of outdoor displays.)
At the other end of the LED-display technology spectrum, we have the TVs and computer monitors characterized as LED displays. But these have always been liquid-crystal displays (LCDs) with LED backlight units. All the way back in 2006, such an LED-backlit, 40-in. TV was released at $3000. Of course, LED-backlit TVs are virtually the entire industry today outside of the few self-emissive OLED TVs being sold.
Indoor direct view displays
Now let’s get to the emerging indoor, direct-view LED market. We’re talking about displays that span from the 100-in.-diagonal range (above the commonly-available LCD TVs) up to the 100-ft-diagonal range and what are sometimes called video walls. You will also hear these displays referred to as signs, because much of the application for such displays has been for dynamic signage installations. That usage will continue along with broader usage in applications such as the cinema or the aforementioned hospitality setting in the Live! restaurants.
You will see these displays popping up in places such as convention centers, where event organizers rent the signs and use them for sponsorship deals. Similarly, the hotel industry is an early adopter. And the technology is coming to corporate boardrooms and even commercial sales operations. We have an article about a project supplied by PixelFLEX in a New York real estate office with the display providing customers with an immersive virtual reality (VR) experience.
Return on investment
Many of the businesses that will buy such video displays have a business model that directly pays back the upfront investment. An example is the convention-center sign rental application we mentioned earlier. In corporate boardrooms, the displays are mainly a status symbol. Restaurants, meanwhile, recoup investments by presumably drawing more patrons.
Consider the Live! restaurants. We had a chance to see the screen at Sports & Social Atlanta – Live!, located in The Battery entertainment district adjacent to the new Atlanta Braves baseball stadium, SunTrust Park. The main display at the restaurant measures 32 ft diagonally, or around 28 ft wide and 16 ft tall in an HD configuration.
Neither Cordish nor any display manufacturer or AV integrator has released further details on the project. But Bob O’Brien, founder of analysis firm Display Supply Chain Consultants (DSCC), speculated that such a screen might use a pixel pitch in the 2.7-mm range. That would equate to more than 5 million RGB LED pixels — and actually, there are three individual LED chips that comprise each pixel.
We found no one who would speculate on what such a display might cost, but we would assume in the low-millions range. Indeed, O’Brien said the cost of such displays is more proportional to pitch than to size, because pitch determines how many LEDs are needed and how many driver ICs are needed. And Live! has much larger displays in its portfolio. Fox Sports Midwest Live! – Ballpark Village in St. Louis has a 40-ft display. That installation is featured on our cover and clearly demonstrates how well such displays perform even when significant ambient light (in this case, sunlight) is present. Meanwhile, Live! Arena – Texas Live! in the Arlington Entertainment District has a 100-ft screen.
In contrast, Auburn University’s Jordan-Hare Stadium has the largest video board in college football with Daktronics having supplied the display (see the sidebar photo below). The 190×57-ft display uses only 8.7 million LEDs because the pixel pitch is far larger than the indoor displays we have been discussing.
LED display architecture
Now let’s discuss the structure or architecture of a direct-view LED display. The end display consists of square or rectangular panels or modules that, like building blocks, compose the display or video wall. The panels fit together tightly so a viewer can’t detect a seam such as the inherent seam visible in video walls built with even the best LCD panels. The panels can also be combined in novel ways to deliver 3D displays, as in a project supplied by PixelFLEX shown in Fig. 2.
Osram makes the Displx products in sizes as small as 0.8 mm per side. Such components would support a display with 1-mm pitch, but most displays today are still at much larger pitch ranges. David Venus, chief marketing officer at panel and display maker PixelFLEX, said the sweet spot in the indoor market today is 3–6-mm pitch.
Back to the supply chain, there are new players to the LED industry looking to grab a part of the direct-view LED market, and many are from China. Indeed, Bheda from IHS said China intends to dominate the market. Companies such as Nationstar and Multi-Color are bringing far less expensive RGB LEDs to market, although quality and reliability are largely unknowns. And those companies appear to package individual LEDs into RGB components but don’t make the individual LEDs. Still, we have learned that even major display makers such as Daktronics are offering some of the lower-cost LEDs as an option.
At the same time, Bheda said, manufacturers of LCD panels that are based in China are working to enter the LED panel space because the transition to LED technology is clear looking forward. She said, “All LCD manufacturers are venturing into direct view because of cost declines.” Bheda projected that LED video-display area shipments would grow 36.7% in 2019 to 1.1 million square meters and $5.1 billion in revenue, with area shipments projected to hit 2 million square meters by 2023.
Continued cost declines, however, must come from technology advancement and not just from lower-cost LEDs. At some point, using pick-and-place for millions of LEDs in a display just makes no sense. Moreover, pick-and-place may not even work as LEDs get smaller. Some TV makers believe that microLEDs measuring less than 100 μm (microns or micrometers) are the future of consumer TVs, and miniLEDs, measuring 100–300 μm, are poised to take over in backlights.
There are numerous obstacles to such smaller LEDs including getting the needed brightness from such small surface areas, thermal mitigation, and making reliable electrical connections to small contact areas. But the largest obstacle is how to get the LEDs onto a substrate using some kind of cost-effective, mass-transfer process rather than placing one LED at a time on a substrate.
There are monochrome applications such as heads-up displays or augmented reality headsets that allow manufacturers to use an array of LEDs in monolithic fashion sliced directly from a wafer. Plessey, for one, has been pursuing such technology. And Osram recently discussed using such techniques for automotive headlamps.
But color displays need RGB LEDs mixed in pixels and those three different monochromatic LEDs come from different wafers. Apple and major consumer electronics companies including Samsung and Sony have spent fortunes working on mass-transfer concepts. But as our Last Word column illustrates, Apple still can’t make the technology cost effective even in a much smaller Apple Watch display.
COB technology as a bridge
Realistically, the LED video display market already needs a mass-transfer approach at the finer-pitch end of the market today. And chip-on-board (COB) technology is entering the space. Note that we most commonly use the COB acronym to imply a high-power or superhigh-power packaged LED that consists of an array of many small LED chips, all covered in yellow-orange phosphor that looks like a fried egg. But generically, COB implies that unpackaged semiconductor (including LED) chips are affixed directly to an application-level substrate as opposed to encapsulation in a dedicated component package.
IHS’s Bheda said she is seeing increased usage of COB technology already in video displays. But we have found that companies don’t utilize the terminology accurately or consistently. PixelFLEX, for instance, refers to its lowest-pixel-pitch FLEXUltra products with PixelShield technology as being COB based. But images on the company’s website clearly show SMD packaged LEDs in use. PixelShield is one of the technologies meant to eliminate any reflections from the display that we discussed earlier.
The point is that COB technology under development and in use to a degree is already exploring mass-transfer, mounting, and electrical connection techniques that will transfer to microLEDs. LED manufacturers, panel makers, and display makers are all pursuing the challenge. And it will likely come in phases. Mike Martens, senior manager of product marketing at Osram, said his company hopes to add value upstream reminiscent of how LED manufacturers are supplying Level 2 modules to lighting companies. Meanwhile, LED packaging companies are trying to deliver multipixel LED modules. TSLC (owned by financially-troubled SemiLEDs) has shown a 4×4, 16-pixel array in an SMD package and says it is working on a 64-pixel package.
The question is how soon such technology will be widely available, and how much cost can be removed from the manufacturing operation. IHS is also following the microLED market and has said that a 1.5-in. microLED for a watch would in 2026 cost 10% of what it costs today. Similarly, a microLED for a 75-in. display would fall to 20% of what such a display would cost today.
Cost and market today
So where do we stand today? First, let’s look at an extreme end of the spectrum. After showing microLED TV prototypes for several years, Sony recently announced commercial availability of the Crystal LED display system at the CEDIA Expo. Given that it’s a modular product, a consumer could order a Crystal system in custom sizes and at a choice of resolutions. A 16×9-ft display with 4k resolution is $877,000. At least it comes with installation and a five-year service contract. And the price can go into the millions if you opt for a finer-pitch 16k resolution.
But at the other end of the spectrum, pricing isn’t quite so jaw dropping. Venus of PixelFLEX said his company does many projects with cost in the five-figure range, although he admits that some do reach six or seven digits. That New York office project we mentioned earlier would be less than $60,000 and could be quite a lot less depending on the specified pitch and LEDs. That price level could be justified by increased sales fairly easily.
The LED technology may also get a boost from an unexpected application — the cinema. Now LED displays offer many advantages over projectors, starting with brightness and great viewability in brightly-lit environments — thus the usage in sports-oriented restaurants. But cinema goers are accustomed to, and apparently, like, the dark environment of a cinema. So brightness is of lesser concern.
Samsung, however, is pushing deployment of its Onyx cinema systems globally. The first installations came more than a year ago in Asia. The company now says it has installations in 16 countries including one at a high-end Texas cinema called Star Cinema Grill.
Still, O’Brien of DSCC expects a moderate-paced rollout of LED displays in the cinema market. He said multiplex locations are likely to install LED technology in perhaps one of their theaters, giving them the ability to host events beyond regularly-scheduled movies in the LED-equipped room. But Samsung is apparently helping customers with financing to accelerate the deployments.
What direct-view LED comes back to is the experience, and it is quite amazing. The brightness is great. And the fast pixel-response rate enables what the video industry is calling HDR (high-dynamic-range) picture quality. If the mass-transfer challenge is overcome, video displays could easily become the largest consumer of LED epitaxial real estate.
Putting the pixels into perspective
As mentioned in the preceding article by Maury Wright, LED display makers have gone for the gusto in scaling brilliant video to large-area displays both indoors and out. While the preceding feature focuses on large, indoor direct-view LED displays, these advanced and giant high-definition screens would not be possible without the advances leveraged and lessons learned in outdoor LED display technology.
Comparing variations on outdoor LED video installations really emphasizes the distinct advantages that will be gained by utilizing small-pixel-pitch LEDs to deliver a high-quality video experience. The nearby photos demonstrate the differences between two of these video techniques.
Consider built-in façade displays, such as the one we wrote about gracing the front of the Cleveland Institute of Art back in 2016 (top). That display, mounted on a stainless-steel metal fabric called Mediamesh and designed by GKD Metal Fabrics, utilized fewer than 72,000 pixels in a total display area of 150m2 (about 1615 ft2).
Not even a year before, LED video display provider Daktronics signed on to supply Auburn University’s Jordan-Hare Stadium with the largest LED video display in college football. At about 10,800 ft2, the Daktronics display relies on nearly 9 million LEDs to produce high-quality, vibrant-color video replay and fan experience content as seen in the photo (bottom).
The stark contrast in video output demonstrates how the application needs dictate the execution — live action footage in the outdoor stadium enhances the fan experience, while artistic graphic messaging enlivens the simple architecture of the educational building. — Carrie Meadows