Proposal and design of hybrid light guide plate based on aspheric concave surface and micropatterns to improve illuminance and color uniformity for LED display

A novel hybrid light guide plate (LGP) for large area light emitting diode (LED) display was proposed by combining the advantages of both directand edge-type backlight units (BLUs). The newly proposed hybrid LGP consists of a thin plate with specially designed aspheric concave structure on the top surface and semispherical micropatterns on both the top and bottom surfaces to enhance light uniformity and decrease color variation. The optical characteristics were investigated to realize the optimized geometry for improving the optical efficiency and uniformity. Ray-tracing simulation results for the 55 in. display show that the illuminance uniformity, optical efficiency, and color coordinate deviation are more than 96%, 81.5%, and less than +0.004, respectively. In addition, this hybrid LGP has an advantage of thinner thickness and less number of LEDs over the commercial direct-type LGP as well as a much lower color variation over the edge-type LGP.