Design of a brightness-enhancement-film-adaptive freeform lens to enhance overall performance in direct-lit light-emitting diode backlighting.

ABSTRACT

In this study, a brightness-enhancement-film- (BEF) adaptive method is proposed to design freeform lenses for enhancing brightness performance in a direct-lit light-emitting diode (LED) backlight system. A detailed design algorithm is presented based on the analysis of the output optical properties of the BEF. By introducing a constriction factor, we can control the light intensity distribution curve at will to adapt to the characteristics of the BEF and make more light transmit through the BEF. Compared with an LED backlight system without a freeform lens, the BEF-adaptive lens method can improve axial luminance by 20.67% and output efficiency by 6.02%.