在液晶显示产品中，透过率是一个重要的光学特性指标。为了满足视角等光学指标要求，液晶显示产品会设计改变其偏光片透过轴的方向。在屏内部设计不变的条件下，不同偏光片方向对产品的透过率具有显著的影响。偏光片与背光存在匹配性问题。本文通过实验及理论研究，表明对于仅改变偏光片方向的产品而言，背光的偏振特性是影响相对透过率差异的主要因素，棱镜片是引起背光偏振特性的主要因素，背光主偏振方向与棱镜片方向近似垂直。在3°棱镜片背光架构下，相对透过率差异与背光偏振度呈线性关系，线性度达0.99以上。

Transmission is an important optical parameter in TFT-LCD products. In order to reach some optical requirements, such as view angle, the transmission axis on polarizer film of TFT-LCD product is changed. However, there are obvious differences in the transmission of the TFT-LCD products which have the same bare cell design but different transmission axis on polarizer films. The polarizer film and the backlight unit should be matched. In this paper, the experimental and theoretical studies show that the polarization property of backlight unit is the primary factor on the obvious differences in the transmission. The polarization property is mostly influenced by the prism film. The main polarization direction is approximately perpendicular to the prism direction. In the condition of 3° prism backlight unit structure, the transmission difference and the degree of polarization of backlight unit are linear relations. The linearity is more than 0.99.