Development of Halftone Photospacers for High Definition LCD Panels

What are Photospacers (PS)?

Photospacers

The structure of the LCD panel consists of a liquid crystal sandwiched between two glass substrates. The "spacer" keeps the distance between the two substrates constant and the thickness of the liquid crystal constant, and plays the same role as a pillar in a building (Fig. 1a). In recent years, it has become commonplace to view images on smartphones, and displays have become increasingly high definition, but with conventional design dimensions, the pixel area (CF) shrinks as higher resolution is achieved, resulting in reduced brightness and increased power consumption (Fig. 1b). In order to expand the pixel area, TFT wiring and black matrix (BM) are becoming higher resolution, and high definition photo spacers are being used to match the wiring and BM design (Fig. 1c).

Fig. 1

Halftone

We have materials that are suitable for the halftone process (a patterning process using a photomask with different light transmittance, e.g. 0%, 20%, and 100%), allowing us to change the height of each spacer with a single exposure (Fig. 2).

Fig. 2

Terminology