Improvement of luminance and uniformity of light guide panel using scatterer pattern by laser processing

Light guiding panel (LGP) is major device in back light unit (BLU) of liquid crystal display (LCD) and determines the optical property of the LCD in terms of average luminance and uniformity. Previously proposed scatterer patterns had problem of non-uniform luminance such as high concentration of luminance near an entrance of a light source. In this paper, V-groove based scatterer patterns were proposed to improve the performance of the LGP. With changing interval between V-grooves and depth of V-groove itself, various patterns were prepared. The feasibility of the designed model was checked with simulation, which calculates luminance value over the LGP surface based on ray tracing technique, and the obtained results were analyzed to determine optimized fabrication conditions in experimental implementation. In modeling of the scatterer patterns, two different kinds of the patterns were considered: one is the pattern composed with regular V-groove interdistance at the same depth along the LGP length, and the other has regular arrangement along the length but different depth. From the results of simulation, experimental inscription with CO2 laser was done. The implemented pattern consisting of V-grooves with linearly increasing depth of the slope of 3.2° has proved good possibility. The proposed LGP pattern is expected to be a good alternative to expensive and time consuming fabrication process, which could be a good solution for highly efficient LGP for LCD in the near future.

► The scatterer patterns were specially designed base on the V-groove pattern for light guide panel. ► After research with simulation method, experimental inscription with CO2 laser was done. ► The adoption of the pattern with linearly increasing V-groove depth demonstrated good possibility. ► With this special pattern, high improvement of the average luminance and uniformity was achieved. ► The proposed LGP pattern is expected to be a good alternative to expensive and time consuming fabrication process.