I'm posting this because I've read it three times and I still can't really get a grasp of it.
First let me say that while the BNP Paribas report that you posted a few days ago was very good, the most glaring error was with respect to WOLED TV's. These are NOT televisions with a white OLED backlight of a normal LCD display (they both use color filters but the LCD also has a liquid crystal layer). They are OLED televisions with a different architecture that has some pluses and minuses.
Back in 2009 LG-Display buys Kodaks OLED unit, now in 2012 LG-Display shows the world largest 55 inch OLED-Tv with Kodaks developed WOLED technology at the CES-2012. We give you more informations how this technology works.
One of the concerns for OLED technology has been the lifetime of the blue color, which has historically been less than red and green. Over time, this results in very dim blue pixels and shifting of the display toward yellow. With this new architectures to overcome this issue, in particular a very stable White OLED formulation, which can be used in combination with a color filter array to produce a full-color display. LGs White OLED architecture boasts a lifetime in excess of 100,000 hours. There are 8,766 hours in a year, so these devices are very stable. Another advantage of the White OLED approach is the elimination color shift over time due to one color dying out more quickly than the others.
Instead of laying down individual red, green, and blue emitters (pixels), LG is going to have an emitting layer that only produces white light. They then take that white light and run it through red, green, and blue color filters to produce the various colors. The problem with this approach is that the color filters drastically reduce the efficiency of the display (increased power consumption). So LG will also have a 4th pixel which will allow unfiltered white light through. That should help the power consumption but it will still be more than the RGB architecture that Samsung uses.
The advantage of this approach is two-fold. One is that manufacturing is easier and involves fewer steps. The RGB approach requires a shadowmask to lay down the individual red, green, and blue emitters (pixels). It is tough to scale the size of the shadowmask to larger substrate sizes. The second is that the white emitting layer is fairly stable over time. You dont have to worry about the blue emitter aging faster than the red and seeing display quality suffer over time.
One interesting question about this display is what approach LG is using for the white emitting layer. There are different ways to produce white light and some, such as a tandem white OLED, involve using quite a bit more material than others.
Hope this helps, but let me know if I have just confused you more.
Slacker |
