LAUSR

Vertical alignment (VA) mode liquid crystal display (LCD) is widely used especially in large size display market because it shows very high contrast ratio in the normal direction and wide viewing characteristics, achieved by many efforts 1)-7). However, much wider viewing angle is required in the movement of high definition from Full-High Definition (FHD) to UltraHigh Definition (UHD) because of its short preferred viewing distance 8)9). As a reasonable method to measure viewing angle of display, the color viewing angle has been suggested 10). This is angular range of low color shift from the normal direction. In particular, the color viewing angle is defined as the angle range within the noticeable threshold of ∆u'v' = 0.015, where u'v' is average value of 9 colors (dark skin, light skin, blue, green, red, yellow, magenta, cyan and gray in the Macbeth Chart). UHD display should require the color viewing angle above 100°, which is horizontal viewing angle at the preferred viewing distance. Some approaches such as the capacitive coupled method and the two-TFT method have been proposed to improve the gamma curve of VA-LCDs 4)6). However, the color viewing angle did not reach 100° and also these methods require complex electronic circuits. In addition, the manufacturing cost and device power consumption increase when two TFTs are used in each unit pixel. To overcome these drawbacks, we achieved outstanding wide viewing angle characteristics by applying the microstructure film without these complex circuit technologies. This film can control the scattering characteristics with the shapes of the internal air-micro cavities capped by black dots. In the case of TN-LCD, we could drastically improve the viewing angle characteristics by just attaching the film to the surface 11)-16). However, in the case of 4-domain VA-LCD, improvement effects by attaching the film were limited 15). Therefore, for VA-LCD, we optimized the backlight (BL) distribution and the LC alignment direction as well as the scattering profile of the microstructure film.