The Application of Ansperical Microlens Array on Direct Backlight System

This paper reports the design of a novel aspheric microlens array (AMA) with high fill factor for direct light emitting diode (LED) backlight system. The AMA mold for patterning transformation was fabricated using the processes of glass wet etching, electroplating, photoresist spin coating and heating encapsulated air. Different from the fabrication results by well-known techniques, the proposed AMA has the features of 100% fill factor and square foot boundary with continuous surface-relief profile. A typical fabrication result, polysiloxine-based AMA with pitch size of 200 μm on a 4 inch glass wafer, has been used for the identification of the optical performance. Experimental results reveal that the radiation patterns and intensity profiles of the light source by using AMA as a light guide diffuser is highly effective in increasing the brightness and uniformity. keywords-aspheric microlens array, fill factor, backlight system, diffuser