Surface Modification for Advanced Light Guide Plate for TFTLCD Display

Abstract

Techniques for performing uniform and high brightness is very important for TFTLCD display. The backlight module with light guide plate (LGP) is the key to achieve uniform and high brightness. Surface modification on light guide plate (LGP) can enhance the brightness and uniformity of TFTLCD display. A novel design, which integrates the merits of diffraction optics and forming technology, is proposed in this research for the higher brightness of LGP. A light guide plate with diffraction grating has been designed. The light emitting surface has a plurality of diffraction grating units. Each diffraction grating unit has a strong diffraction portion and a weak diffraction portion. They are orthogonal each other. Area ratios of the strong diffractive portions in the diffraction grating units proportionally increase with increasing distance away from the light incident surface. Two LGP designs with diffraction optics have been demonstrated. One is for large size TFTLCD displays with CCFL as the light source. Another one is small size TFTLCD displays with LEDs as the light source. Both designs with diffraction optics on LGP can increase the overall efficiency of utilization of light with high brightness and uniformity.