直下式LED背光源模组第二扩散导光板光学特性分析

针对直下式发光二极管(LED)背光源模组均匀度低且模组厚度大的缺点,提出了加入第2扩散导光板的直下式LED背光源模组,并采用九点取值法及TRACEPRO软件,模拟了第2扩散导光板入光面及出光面、高度和厚度对背光源模组光特性的影响。结果表明,第2扩散导光板的入光面及出光面对背光源模组均匀度的提升影响较大。当入光面采用凹陷结构、出光面采用弯曲结构时,有利于增大模组均匀度;且模组的均匀度分别随凹陷结构半径的减小和弯曲结构半径的增大而增大。而其高度和厚度主要影响背光源模组的光斑显示效果,随着高度的增加,光斑范围增大,暗区团逐渐减小;随着厚度的增加,照度最大值增大但亮点增多,产生亮暗不均的现象,从而影响了背光的主观效果。

Optical performance of secondary lightguide-diffusive component in direct LED b acklight module

According to the situation of low unif ormity and large thickness of direct-type LED back light module (BLM),optical s imulations based on nine-value method,combined with TracePro are performed to investigate optical properties of secondary lightguide-diffusive component in direct-type LED BLM.Effects of incident surface,exit surface,height and thickness of seconda ry lightguide-diffusive component on optical performance of direct-type LED BLM are studied theoretica lly.Simulations reveal that the uniformity of direct-type LED BLM is mainly dependent on the in cident surface and exit surface of the secondary lightguide-diffusive component.The uniformity is incr eased when the incident surface is depression structure and exit surface is bending structure,and the uniformity has slight increase as radiu s of depression structure decreasing and radius of bending structure increasing, respectively.The height and thickness of the component can influence the facula display effect of direct-type LED BLU.The boundary o f facula is slightly expanded and the dark space group is shrinked as the height of component increases.The illumination maximum and number of lightspots increa se as the thickness of component increases, respectively.Then the uneven light and dark phenomenon happen,which affect the b ack light subjective effect.