THE APPLICATION OF ANSPERICAL MICROLENS ARRAY ON DIRECT BACKLIGHT SYSTEM
C. Tsou, T. Lai, C. Huang, C. Chang, C. Wu
Feng Chia University, TW
Keywords: aspheric microlens array, LED, backlight
Abstract:Today’s liquid crystal displays (LCDs) have to achieve more brightness and better uniformity in a thinner package, especially for the large-sized LCD panels with direct-type LED backlight system. Different reflective and transmissive characteristics managed by several key elements are expected to significantly affect the brightness profile. However, commercial diffusing component consisting of lower diffuser, brightness enhancement film (BEF) and upper diffuser could reduce the brightness significantly with low uniformity. Thus, microlens array as a light diffuser became the most advanced solution. Based on the requirements of microlens application, this paper proposed the design of the novel aspheric microlens array (AMLA) diffuser and aspheric micromirror array (AMMA) reflector for direct light emitting diode (LED) backlight system to increase backlight brightness and get better uniformity. The AMLA mold for patterning transformation was fabricated using a heating encapsulated air process. Based on the AMLA mold, the AMMA was fabricated on the reflector by the deposition of Al film. Experimental results reveal that the radiation patterns and intensity profiles of the light source by using the novel aspheric microlens array (AMLA) diffuser and aspheric micromirror array (AMMA) reflector is highly effective in increasing the brightness and uniformity.