Abstract
In recent years, liquid crystal displays (LCDs) have been the most widely used apparatus in various applications as information display devices, such as computer, communication, and consumer electronics due to the thinner size and lighter weight. One problem facing current LCD backlight unit is its low efficiency in the viewing direction. Several geometrical optics or physical optics methods have been proposed to improve the light illuminance and uniformity by optimizing the structures on the light bar to control the scattering directions and eliminate the dark region or hot spots in this viewing direction. This research uses a roll-to-roll imprinting process based UV resin process to make sub-wavelength gratings for display applications. Based on the rigorous coupling wave analysis (RCWA), we analyze the relationship between the 1st order transmission/reflection efficiency and grating’s pitch under various shapes while rays passes through sub-wavelength gratings, which are patterned on a backlight. The target is to turn the R/G/B (625 nm、525nm、465nm) incident rays into a uniformly and normally output white light with high illuminance from the surface of a light bar.