Sony’s XEL-1 OLED TV is gorgeous and impossibly thin; there is no argument possible about either of those facts. And that’s enough to make people go gaga over it, even though it is about one sixteenth the size of a 42″ 1080p LCD TV and more than twice the price. Oh, and it’s not even HD. But it still looks cool.
Sony says that it’s good for 30,000 hours, or about 10 years of service. DisplaySearch begs to differ, having conducted its own tests. According to their press release, the unit will be half as bright after just 5,000 hours of showing a full white image, and after 17,000 hours of typical video content. The reason for the difference is that the OLED phosphors grow dimmer with use, and a full white image uses all the pixels all the time. A typical movie scene uses less than 25% of the available brightness in the display, and video content falls somewhere between those two proportions.
More disturbing are the results on “differential aging”. The problem with OLED materials is that the blue phosphors lose their brightness much faster than the red and green phosphors. According to DisplaySearch’s tests, after just 1,000 hours of use the blue phosphor light output dropped by 12%. This is in contrast with the 7% drop for red and 8% drop for green. If the set were to include a feedback circuit that would lower the red and green levels to match the blue output, then the set would reach half brightness that much sooner. But if no adjustment is made, then the image will become yellow; red, green, and blue make white, but with less blue, the red and green will give the image a yellow tint. This is hardly acceptable for a product as expensive as the Sony OLED TV.
The danger here is that people may decide that OLEDs don’t work, based on their experience with the XEL-1. This happened with the early plasma HDTVs; the technology is still trying to live down the reputation for short lifespan and permanent image burn-in problems.