When it comes to large screen indoor video walls & displays, one technology has ruled them all: LCD flat screen panels. However, that may be about to change. With the introduction of new, more affordable fine-pitch direct-view LED screen displays (and new high-ambient-light screens coupled with new solid-state laser projectors – which we’ll cover in another blog post), large LCD panels (above 100″) and video walls may have met their successor. Let’s take a look at what’s happening.
Shows like the Digital Signage Expo (DSE), recently held in Las Vegas, provide clues to the changing display landscape.
First, let’s look at why traditional video panels, made up of several LCD panels with thin bezels and frames, have become popular. The main reason is simple: they have been the lowest cost, reasonable-quality way to do video and information displays in large sizes. You can see them as backgrounds in almost every newscast, in shopping mall displays, as command and control center dashboards, lecture halls, and even in some hotel lobbies.The newer video walls use LED panels as the light source behind the LCD glass – so they are reasonably reliable and their bezel thickness or window frame is rather thin(and they keep getting smaller). So why the need for a better solution? Let’s look at their disadvantages.
Traditional LCD video walls have bezel lines and challenges with calibration – as seen here.
Downsides of Traditional Video Walls:
1. Smaller video walls like a 2 x 2 panel configuration can now be done with a single, cost effective LCD panel
2. Each panel in the video wall must be calibrated and re-calibrated on a regular basis to maintain even brightness and color uniformity (see picture above)
3. No matter how small the bezel width between the panels, it is still a break in the image and a visual distraction to the message
4. As soon as you go larger than a 3 x 3 panel configuration, the fine pitch of the panel is not able to be utilized nor is it generally even needed – because most video walls are designed to be viewed from a distance
5. Most video walls are very directional – color, contrast and brightness falls off unless you are directly in the front and center of the display
New Cost-Effective Alternatives to video Walls
Larger, brighter, and more vivid displays are now possible at almost the
same cost as traditional thin bezel video walls and without the annoying lines in the image. (Note: the display image above is purposely overexposed so you can see the environment – which was very bright but looks dark in comparison to the very bright image.
Fine-Pitch Direct-View LED Video Displays
Direct-view LEDs have been around for quite a few years. However, it has only been recently that fine-pitch indoor-viewing LED panels have become more affordable. Outdoor direct-view LED screens are familiar to everyone – most have seen them as electronic billboards, very large stadium replay screens, and those really large video screens in Times Square and the Las Vegas strip. However, that is not what we are talking about here – but they are related. The outdoor direct-view LED screens are bright, colorful, and have great contrast, but if you get close to one, they are very pixelated and annoying. That’s because the outdoor direct-view LEDs are designed to be seen only from a distance, like 75′, 100′ or 200′ or more. But instead of talking about those, we’re talking about fine-pitch (a pitch of 3mm or smaller) direct-view LED displays . Here’s a great example to help you understand:
This display by Samsung, seen at DSE 2017, shows the beginning of fine-pitch direct-view LEDs in the upper left at 3mm. Typical outdoor LED billboards are 16mm or 20mm.
LEDs are Not Always LEDs!
Before we go into this next part we need to clear up a little confusion. The ads you may see for 4K flat screen TVs often just say 55″ or 75″ LED 4K TV. Those are not direct-view LED screens – those are LCD screens using white or blue LEDs as a light source for the LCD screen. That is also what is used to make most video walls – but those are special versions with very thin bezels. One of the challenges with LED/LCD TVs is that it is very difficult to get really high contrast (their blacks appear milky) and high light output (nits). The LED screens we are talking about here are red, green, and blue self-emitting Light Emitting Diodes or direct-view LEDs. We now have direct-view LED screens (indoor, fine-pitch) that have dot pitches under 1 mm. When the individual LEDs are off, they can have almost perfect blacks – unlike LCD which always has some back light scatter which displays as imperfect blacks. That means that LED screens can now have very high resolution, very high contrast, and very close viewing distances.
Very fine pitch direct-view LEDs, like this one at DSE 2017, are very bright and look great even as close as a few feet away. (In this image, the camera was exposed so you could see some of the LED image but the room environment is bright as well. Cameras just cannot capture both areas at the same time.
Advantages of Fine-Pitch Direct-View LED Displays:
1. Excellent contrast that far exceeds the best LCD technology
2. Extreme brightness that exceeds even the brightest LCD displays
3. No visible bands or bezel edges in the image – just full clear images
4. Long life – typically 70,000 hours to half brightness
5. Available in 3 mm to less than 1mm – for almost any indoor viewing application
6. New LED panel screen sizes, of up to 54″, simplify large video display projects
7. New production and volume manufacturer of LEDs has made this technology competitive with some video wall projects starting this year
Conclusion
We are finding that many in the industry (traditional AV dealers) are not aware of this new trend of migrating to new fine-pitch direct-view LED displays – or are not even aware of the new price levels that are now available from some core LED manufacturers. It seems that almost every major manufacturer of flat screen panels is very aware of this migration – hence the presence of these displays in almost all of their booths at the Digital Signage Expo (DSE) this year. Unfortunately, those same manufacturers are the ones that could be left with a lot of LCD inventory if they do not keep up.
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