OLED

Arguably the big buzz of the entire industry these days in terms of new display technology is OLED. Sony is leading the pack at the moment having brought the first model to market with their XEL-1 with a screen size of eleven inches diagonal, a native resolution of 960 x 540, and a whopping list price tag of $2,500. Currently the company is only producing the XEL-1 for the NTSC television system, which of course includes the Japanese and U.S. markets.

A technology now over twenty years old, OLED (Organic Liquid Emitting Diodes) was invented by Eastman Kodak in 1987 by C.W Tang and S.A. Van Slyke. Today, a host of companies are investing heavily in R&D to bring OLED to market in a variety of different kinds of products.

Sony started its research and development on OLED for television products in 1994. The structure of the display itself is fairly simple, and the bill of goods for manufacturing will eventually be low making the products affordable to the masses at some point in the hopefully not too distant future. The first prototype, a 13-inch SVGA (800 x 600) resolution panel was built in 2001. Two years later, Sony built its second prototype, a 24-inch model, and the company brought its first model to the Japanese market later that same year. A Sony developed technology dubbed ‘'Super Top Emission'' maximizes power efficiency and contrast ratio. Contrast ratio is further enhanced by the use of Micro Cavity technology, and color filters with almost no internal reflections. Sony claims a contrast ratio of 1,000,000:1 for their current 11-inch model. The company also showed a prototype 27-inch model at this year's CES (Consumer Electronics Show) show in Las Vegas.

The current 11-inch model has a metal mask similar to the metal shadow mask that CRTs employed behind their glass screens. The XEL-1 currently uses a glass screen with a total thickness of 3mm. At this thickness, an outboard control center housing the connectivity and tuner is obviously necessary. We were shown a small 3.5 inch prototype that was an amazing .3mm thin. Sony estimates the life span of OLED to 50% of peak light output to be approximately 30,000 hours. This is due mainly to the limitation of the life of Blue, which has been a major challenge to the technology. According to Sony, OLED maintains a much larger color gamut at low light or dark areas of the picture than other display types.

For larger screen sizes a maskless chassis will have to be developed. Sony has budgeted 220 million dollars to bring larger screen sizes to market starting in 2009, and it is actually a mandate from CEO Howard Stringer.  Eventually, the goal is to utilize a type of polymer or plastic material for the screen to make it extremely flexible. This would eventually lead to rolled goods like window shades that drop down covering your window that turn into a TV. How about table clothes in restaurants that light up and turn into a menu! Obviously the applications extend way beyond TV, making OLED an incredibly far reaching display technology. The picture quality of the XEL-1, even though the resolution is not high enough to be considered HD, is subjectively excellent, mainly because of extremely high contrast ratios due to the incredibly good black level performance. The color also looks to be fairly accurate. For an in-depth review of the XEL-1 complete with lots of technical details read Tom Norton's excellent review in the July issue of Home Theater magazine.