OLED Display Fundamentals and Applications

6

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.

6.1 COLOR-PATTERNING 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.

6.1.1 White + Color Filter Patterning

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 [1] and color filter absorption of emitted light to tune the color.

Figure 6.1 Schematic depiction of the RGB pixelation method.

Figure 6.2 Schematic representation of the white + color filter method.

The shadow masking process, which patterns the OLED ...