According to Digitimes, Apple and HP is developing LED backlights to replace existing CCFL backlights in their notebook PCs. The LED backlit notebook PCs are slated for a second quarter 2007 launch. The replacement of CCFL with LEDs will lead to dramatic improvements in image quality, better light distribution and improved color range. Apple likes to use Nichia given that the company has a near-monopoly for Apple’s iPod displays. I am assuming Nichia’s LEDs can hit the 1,680 nits mark that is stated as a standard brightness level for a LED. Of course, with many parts of the LCD reducing the brightness (the color filter taking care of 70% of it), you will need many LEDs to get to a 200-300 cd/m2 level at the front of the LCD. HP’s LED-based notebook PCs will be geared toward the high-end multimedia customer segment.
There’s some problems with this news item. First of all, using LEDs for notebook PC displays will not improve anything in the way of front screen performance. The reason is because of the type of LEDs that are used for notebook PC applications. White LEDs are used that is a combination of a blue LED chip with a yellow phosphor coating. There are other variations, but the end result is a color gamut about the same as a typical CCFL backlit LCD of around 40-45% NTSC. There are already advanced CCFL backlit LCDs that reach 72% NTSC on notebook PCs today. Color uniformity will be a big issue for LED backlit LCDs if the sizes become much larger than 12″ or 13″ because the number of LEDs increase quite a bit. The only things that will improve are power consumption, LCD thickness, and durability. On most ultra-portable notebook PCs the use of a LED backlight will improve battery life due to the fact that LEDs consume less power at lower brightness levels. As for thickness, Sony’s TX series notebook PCs is a good example of how thin the LCD can get–very thin. Because LED is a solid-state technology, durability will be better than CCFL.
So, if HP is indeed focusing its LED backlit notebook PC on the high-end market, it will most likely be a 17″ or larger notebook PC with a non-white LED (blue chip with yellow phosphor). It will most likely use a LED package that incorporates three LED chips representing the primary colors, a tweaked color filter to fit the different light frequencies and will certainly require more energy as LEDs at higher brightness do consume more power than CCFLs. The better route would be to apply LED backlights into a smaller LCD and that is what Apple will probably do. The overall result will simply be longer battery life and a thinner LCD, which works well with Apple’s incremental improvement approach within a product’s lifetime.