基于LED背光源区域控制的LCD系统色域分析

介绍了液晶显示(LCD)系统普遍使用的色域计算方法。针对LCD系统的色域主要由背光源的光谱特性、彩膜的光谱透过率特性和液晶面板的特性三个方面的因素决定，采用LED作为背光源来提高系统整体的色彩表现能力，利用色度学的方法，通过对LED背光源光谱的分析计算，比较了有无区域控制的背光源经过彩膜后系统色域的大小，并分析了液晶面板对比度的变化分别对两种模式下背光源色域的影响情况。分析和计算结果表明：采用区域控制的LED背光源可以改善由于彩膜性能的不完善所引起的再现三基色色彩饱和度降低的现象，同时该模式下系统色域受液晶面板对比度变化的影响很小，即降低了系统色域对彩膜性能和液晶面板性能的要求，因此对于提高现有LCD系统的色域具有非常重要的意义。

Analysis of Color Gamut of LCD System Based on LED Backlight with Area-Controlling Technique

Color gamut as a significant performance index for display system describes the color reproduction ability IN real scenes,liquid crystal display (LCD) is the most popular technology in flat panel display.However,conventional cold cathode fluorescent lamp (CCFL) backlight of LCD can not behave high color gamut compared with cathode ray tube (CRT).The common used method of color gamut measuring for LCD system is introduced at the beginning.According to the inner structure and display principle of LCD system,there are three major factors deciding LCD's color gamut:spectral properties of hacklight,transmittance properties of color filters and pedormance of liquid crystal panel Instead of conventional backlight CCFL,RGBLED backlight is used for improving color reproduction of LCD display system.Due to the imperfect match between RGB-LED's spectra and color filter's transmittance,the color filter would reduce the color gamut of LCD system more or less.Therefore,LCD system based on LED backlight with area-control technique is introduced which modifies backlight control signal according to the input signal After analyzing and calculating the spectra of LED backlight which passes through the color filters using method of colorimetry,the area sizes of color gamut triangles of RGB-LED backlight with area-control and RGB-LED backlight without area-control LCD systems are compared and the relationship between color gamut and varying contrast of liquid crystal panel is analyzed.It is indicated that LED backlight with area-control technique can avoid color saturation dropping and have little effects on the contrast variation of liquid crystal panel.In other words,LED backlight with area-control technique relaxes the requirements of both color filter performance and liquid crystal panel Thus,it is of importance to improve the color gamut of the current LCD system with area-control LED backlight.