LED Backlight Module by a Lightguide-Diffusive Component With Tetrahedron Reflector Array

Abstract

In our previous work, IEEE/OSA Journal of Display Technology, February 2012, we examined the luminance and uniformity characteristics of a newly invented secondary optical lens with a wide emission angle called a “lightguide-diffusive component”. The lightguide-diffusive component is designed for thin direct LED backlighting applications. The LED backlight module is composed of at least an LED light source, a secondary lightguide-diffusive component with a micro-structure reflective bottom surface, and a flexible printed circuit (FPC) for LED lighting without a brightness-enhanced film (BEF). Through this lightguide-diffusive component, the emission profile of a single LED is modified to provide better illumination and more uniformity. In this work, the micro-structure reflective bottom is redesigned to be shaped like a Tetrahedron Reflector Structure Array instead of a triangle cylinder structured array, resulting in a more uniform spatial light energy distribution on the emission plane of the LED backlight. The simulation results show an increase in the uniformity ratio with the new design from 72% to 76%, a 4% improvement, the angle of the luminous intensity is increased from 98 deg to 112 deg, a 14 deg improvement, a decrease in the luminance is from 9024 nits to 8551 nits, an impairment of 5%, and a decrease in the volume of the micro-structure reflector from 1.154 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> to 0.767 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , a 33.5% volume reduction (cost saving).