A Highly Directional Light Guide Plate Based on V-Groove Microstructure Cell

A new light guide plate (LGP) with highly directional emission properties based on V-groove cells has been investigated. To achieve high uniformity at normal luminance distributions for LCD backlight units (BLUs), we present a cell composed of multiple V-groove microstructures, and demonstrate its performance in a 10.1-inch BLU. We have found the density of the V-grooves to affect luminance distribution, and the directionality of emissions increases with number of V-groove microstructures in a cell. A cell composed of five V-groove microstructures delivered a 1.9-fold increase in optical efficiency when compared with a conventional BLU: the central luminance was 2.3 times greater, the main viewing angle was at -1°, and distribution of viewing luminance was almost symmetrical. In conclusion, our V-groove cell LGP for BLUs is thin and simple, providing high efficiency and high uniformity at normal luminance distributions.