Next-Generation OLED Technologies
To ensure the success of OLED technology as a major industry, it is necessary to develop strategies to achieve low cost and high productivity, and to develop improved displays to compete with conventional displays and be introduced in new applications on the market. In this chapter we discuss the status of new technologies.
As OLED materials become difficult to process at high temperature and humidity, it is very difficult to pattern the organic layer by means of photo-patterning technology, which is normally used in semiconductors and TFTs. Therefore, the shadow mask technique has been used for the patterning, but this leads to many problems. Various approaches have been developed to deal with these problems.
Figure 6.1 illustrates the conventional RGB pixelation method (also called the RGB side-by-side method). Red, green, and blue emissive pixels are patterned by, for example, shadow masking. On the other hand, Fig. 6.2 illustrates the white + color filter method, which displays color by means of white OLED device emission  and color filter absorption of emitted light to tune the color.
The shadow masking process, which patterns the OLED ...