用于侧出式发光二极管背光的全局动态调光算法

Global dimming algorithm for side-lit LED backlights

结合背光源发展趋势,提出了适用于侧出式LED背光的全局动态调光算法。首先,根据显示图片平均灰度值、最大灰度值和平均值的差值确定背光调光亮度。接着,基于S曲线对液晶像素亮度值进行补偿。亮度大于S曲线拐点的像素的调整因子大于1,小于拐点的像素的调整因子小于1,以此有效提高静态对比度,并且不会引入溢出失真。对算法进行了仿真分析并开发了原理样机进行实际验证。结果表明:采用动态调光算法的液晶显示器的功耗严重依赖于显示内容;显示40幅不同类型的图片时,平均整机节能为9.39%;静态对比度提高了124.7%。采用本文提出的全局动态调光算法的侧出式背光具有成本低、体积轻薄、节能、对比度高的优点。

In consideration of the development trends of backlights, a global dimming algorithm for side-lit backlights was proposed to solve the problems of Liquid Crystal Devices（LCDs） in low contrast ratio and high power consumption. The backlight dimming level was decided by the average luminance and the difference between the average and max grayscales of all subpixels. Then , the S- shaped function was involved to improve the static contrast ratio, by which the pixels with the grayscales more than the turning point of the curve could be become brighter and those less than the turning point could become darker, so that the static contrast ratio was improved efficiently. The algorithm was simulated and a prototype was developed to evaluate the effects of the dimming algorithm. Experimental results indicate that the power consumption of the LCD with the global dimming heavily depends on what to be displayed on the images. For 40 different kinds of images, the average power has reduced by 9.39% and the static contrast ratio improved by 124.7%. The side-lit back- lights performing the proposed global dimming algorithm have the advantages of low-cost, small thickness, low power consumption and high constrast ratio.