Direct-View LED, Pixel Pitch, and Why They Matter!
A decade or so ago, huge, high-impact displays could only be conceived for places such as Times Square, as seen in the photo at right by Javier Gutierrez Acedo, circa 2008. These displays were primarily displaying advertisements at large outdoor venues or in sports stadiums because of the astronomical construction cost.
Fast forward ten years, and you find video wall technology and conference room technology has surged ahead. Direct-View LED (DVLED) displays can now be attained at a much lower cost of entry and in a lot more sizes than most people imagine. The superiority these displays have over projectors or arrayed video walls (comprised of 46"-55" monitors) is significant and apparent. There are no seams, no adverse effect of ambient light, and nearly unlimited contrast, which is the difference between full luminance and total black. It provides a comparable experience to a big-screen TV, only much larger and, in many cases, much higher fidelity.
Moore's law has had a profound effect on Direct-View LED (DVLED) and the cost of implementation.
The law states that the number of transistors doubles about every two years. Encyclopedia Britannica explains that this is because Gordon E. Moore (CEO of Intel) observed in 1965 that the number of transistors on the Intel processor was doubling about every 18–24 months.
HD - 4K - 8K
The ever-growing "resolution race" from TV manufacturers has been all about the pixel count. The evolution of TV resolution over less than 20 years is an excellent example of this. It wasn't that long ago that HD TV was considered incredible new technology. Today, as 4K becomes the norm, a new thirst for yet more is already underway – 8K or bust! What is often overlooked is that most people cannot discern the difference between uncompressed 4K video and anything higher, such as 8K. (a debatable topic of discussion for me, so don't get me started!). It may sound counter-intuitive, but more is not always better with pixel count. This is where pixel pitch and viewing distances make their entrance and why audio visual expertise is so important when designing these systems.
Pixel Pitch is the distance measured from the center of one LED pixel to the nearest adjacent pixel in millimeters.
So if you are planning a video wall, go with the lowest pixel pitch, right?
Well, the answer isn't always that simple. Viewing distance will ultimately determine what pitch and size are right for your application. Is this an outside amphitheater, an auditorium, a large ballroom, or a small boardroom? Native resolutions can range from "HD" resolutions like 720p to several orders of magnitude higher with custom resolutions, and they are all correct for a certain application and viewer distance. The most important thing that matters, in the end, is how close viewers can be to view the video.
There is a reasonably simple way to determine the general pitch required for a given installation. Equate each 1/10th millimeter with 1 foot. This provides a designer with a good starting point, from which he or she can make adjustments as needed. For example, if your closest viewer is 40' away, that would constitute around a 4mm Pitch. And there are sub-mm pitch walls that could get a viewer nearly arms-length from a display, so there is a pitch for almost any application.
The cost implications must be considered, as well. The lower the pitch, the higher the price. The higher the pitch, the larger the display must be to achieve a good picture. A 4mm pitch at 40' will have the same general quality as a 1.2mm pitch wall would have at 12'. So it would not be prudent to place a fine pitched wall for a distance viewer because the detail provided could not possibly be discerned. The "more is better" fallacy might pack in too many pixels for the viewing distance. Plus, that approach will make the installation unfeasibly expensive and provide sticker shock to any who dare gaze at the cost to implement.
The world of large format displays in conference rooms and centers has been exclusively projector territory in the past. This is beginning to change with more creative and impactful installations using Direct-View LED. What used to be considered video wall technology has found its way into meeting spaces. Projector manufacturers also know there may be a paradigm shift in large-format displays in the years to come. If you look at the top 10 reliable and distinct direct-view LED brands, it reads like a who's who of the high-end projector and commercial TV brands. Even movie theaters are looking into this technology.
When it's time to design your next conference room, boardroom, or ballroom, direct-view LED can bring your space to a new level at an astonishingly lower price compared to a few years ago. Just remember to employ an audio visual expert to help verify you get the best solution at the right price.