OLEDNet has posted an interesting article talking about OLED production yields in evaporating deposition equipments. They say that current TFT-LCD production processes take around a minute to complete, while AMOLED processes take around 4 minutes. Both Samsung and LG are developing new ways to make this faster (Samsung is developing a vertical evaporating deposition system, while LG is working on a horizontal one). But even those new methods will still take around 2 minutes.
OLEDNet suggests using a white OLED with a color filter. White OLED can reduce the evaporating deposition time to one minute in In-line evaporating deposition method because it could produce the light emitting floor using RGB and other parts in only one sheet of shadow mask.
There are two major problems with this approach. First of all, white AMOLED materials aren't ready for this yet (but they will be soon). Second, you lose color quality. But OLEDNet claims that such displays will still be better than TFT-LCDs in terms of contrast. OLEDNet concludes that developing white OLED materials should be the core technology for the future of AMOLED displays.