A Novel Optical Sheet with Microstructures Design in the LED Direct-Lit Backlight Module

A novel optical sheet with double-layer microstructures is proposed to improve the brightness uniformity and optical efficiency in the LED direct-lit backlight module. By means of 2D ray-tracing program design and commercial optical software simulation, we enhance the brightness uniformity from 45.3% with traditional planar diffuser to 82.7% with new optical sheet, and the average brightness is promoted about 10.9% in the same frame of backlight module which internal thickness is only 13mm. Thus, this novel optical sheet with microstructures design is useful for a slim LED direct-lit backlight module.