One of the most dramatic improvements for LCD HDTV I saw last week at the Society for Information Display conference in San Francisco was a technology demonstration by a company called Brightside. Like many other companies, they have replaced the typical fluorescent backlights for an LCD panel with LEDs. The big difference, however, is that the Brightview backlight changes the brightness level of each LED depending on the image displayed on the panel.
This means that the backlight creates a coarse, gray image of the picture, behind the liquid crystal layer. How does this help? It means that in areas where the panel is display dark or black content, the backlight for that area will be almost or all the way turned off. And the end result is that the black areas of the image will look much blacker than on a standard LCD. The variable brightness of the backlight also helps produce more shades of color than a standard LCD panel. When viewed side-by-side with an identical LCD panel equipped with a traditional backlight, the difference was astonishing.
At present, Brightside is only building reference design units to demonstrate their technology for panel manufacturers. While their design does add cost, a large portion of the increase is for the LED backlight which are expected to become more common. For the present, they are targeting high-value applications such as medical or digital signage displays.
I think that the effect is striking, but in effect, they are building two separate displays, one on top of the other. Panel manufacturers are looking for ways to reduce costs and complexity, and this approach is headed in the other direction. As a result, I’m not sure that it will catch on, but perhaps there will be lessons from this approach that may be applied to other backlight designs.