针对机载液晶显示的特殊要求,设计了一种四基色发光二极管(LED)背光源。采用了能单独控制亮度的红、绿、蓝、琥珀等4种颜色的LED,以克服现有滤光片方法带来的夜模式下显示色域大幅下降的问题。在昼模式下工作时,4种颜色的LED同时发光,混合成白光;在夜模式下工作时,关闭红色LED以减少红外辐射,而绿、蓝、琥珀等3种颜色LED工作。计算了夜模式下3种颜色的混合配比。将蓝色LED的混光比例作为固定值代入昼模式下计算得到红、绿、琥珀的配比。仿真设计了采用红、绿、蓝三合一LED和单独琥珀色LED的背光源,分析了它们的性能,并开发了实际样品。测试结果表明: 昼模式下,背光模块的发光强度为23 515 cd/m2(屏前亮度为1 175 cd/m2),非均匀性为8.07%,色域为NTSC(National Television Standard Committee)的116.5 %;夜模式下,背光模块的发光强度为15.36 cd/m2(屏前亮度为0.77 cd/m2),非均匀性为15.49%,色域为NTSC的83.5 %,满足机载液晶显示的要求。

According to the special requirements of Liquid Crystal Display(LCD) in an airplane cockpit,a 4-primary-color-based LED(Lighting Emission Diode) backlight is developed. The LED backlight applies LEDs with 4 different colors of red,green,blue and amber to control the lightness independently. In the day model,all LEDs with different colors are turned on to form white lights. In the night mode,the red LEDs are closed to reduce infrared radiation. The mixed ratio of green,blue,and amber LEDs in the night model is first calculated. With the fixed luminance of blue LEDs,the ratios of red,green,and amber LEDs in the day model are decided. The detailed simulations are performed to decide the physical structures and optical characteristics of the backlight. The 3-in-1 LEDs with the individual amber LEDs are applied in a prototype. Experimental results show that the luminance,nonuniformity,and color gamut of the backlight in the day model are 23 515 cd/m2 (1 175 cd/m2 of panel brightness),8.07%,and 116.5% NTSC(National Television Standard Committee),respectively;and those in the night model are 15.36 cd/m2 (0.77 cd/m2 of panel brightness),15.49%,and 83.5% NTSC,respectively. The developed backlight satisfies the requirements of luminance and night-vision-compatibility of aircraft liquid crystal display.