Abstract
The sidelight type backlight sysyem has become popular as a light source for LCDs because of thinness, light weight, high luminance, low consumption power and luminance uniformity. Recently the prism films become indispensable material for high luminance LCD backlight system. However that is an obstacle to a low cost price because of using expensive prism films. We have developed the newdesign backlight system without prism films by using waveguide including the function of prism films.