Study On Design And Manufacturing Technology Of Light Guide Plate With Optical Microlens Array

Light-guide plate(LGP)was first used in the flat panel display industry, and it is a key component of backlight unit(BLU). Lighting field requires LGP has a high brightness of light emission, and then uniformity. The production process of LGP used for BLU was complex, inefficiencies and costly, this leads to a high prices of flat-panel lights. Therefore, for LED flat-panel lights, this paper presents a design and mechanical production method of LGP with micro-lens array structure. The purpose is to realize the efficient mass production of LGP with micro-lens array structure.Firstly, For the design of LGP, the paper mainly studies the patterns, shape and arrangement of micro-lens, and how they influence the efficiency and uniformity of light emission. In the end, a V-cut LGP with a shape of 84 millimeters long, 87 millimeters wide and 3millimeters thick was designed. The result shows, the efficiency of V-cut LGP was 6.5% higher than rectangular-groove LGP and 16.7% higher than spherical-groove LGP. When the depth of V-cut was 100?m, the angle was 120 degrees, and the V-cut were arranged by polynomial form, the LGP has a uniformity of 89% and effectiveness of 64.8%.Then, we developed the micro precision grinding technology by using the V-tip of diamond grinding wheel dressed before, produced high-precision LGP with mirror surface, made the angle error of the V grooves on the LGP surface to be +0.5° and the roughness to be 37 nm. By the third party testing, compared with silk-screen printing LGP, the micro lens array structure LGP increases the luminous efficiency by 7.5% and the luminance uniformity by 26.04%.Finally, in order to increase the LGP production efficiency and reduce production costs, a method of hot embossing was studied, and three cores have been made to use for hot embossing. the micro structures on the cores have a high shape accuracy and mirror surface of nanoscale roughness. For the production process of LGP, we study on the relationships between molding quality and pressure, temperature or pressure-keeping time. The results show that, a pressure of 150 MPa, a temperature of 140 degrees Celsius and a time of 2 second was the best process parameters for the macro hot embossing of LGP.