侧入式局域动态调光背光聚光特性研究

Spotlight characteristics of local dynamic dimming for side-lit backlight

针对HDR技术在侧入式局域动态调光中的特殊要求,采用结构导光板搭配LED灯条进行聚光,以此提高背光对比度,实现液晶显示器的分区动态调光控制。首先,基于现有导光板出光面亮度分布,确定了导光板出光面微结构为锯齿形,然后利用光线追迹法对结构导光板进行仿真,分析了不同结构的导光板出光面微结构棱高、棱宽比和曲率对聚光性能的影响,结果表明,聚光性与导光板出光面结构直接相关,光学胶折射率为1.49,棱高为20μm,棱宽比为0.47时,聚光性能最佳;根据仿真结果开发了实际背光产品,并对此产品进行了测试,测试结果表明,与传统的导光板相比,使用结构导光板后,背光聚光效果显著,对比度由6.01提升到127.15,满足动态调光聚光性要求。

For the special requirements of the high dynamic range local dynamic dimming in the side-lit backlight,this paper proposed the structural light guide plate matching the LED light bars to spotlight,improving the backlight contrast and realizing the divisional dimming control of the liquid crystal display.First,based on the surface brightness distribution of the existing light guide plate,the microstructure surface of the light guide plate was designed as a zigzag shape.In order to analyze the influence of the height,width and curvature of the microstructure on the light-emitting surface of the light guide plate with different structures,the ray tracing method was used to simulate the structure of the light guide plate.The simulation results show that the light concentrating property is related to the light-emitting surface structure of the light guide plate.When the refractive index of the optical adhesive is 1.49,the height is 20μm,and a ratio of the height to the width is 0.47,the light collection effect is the best.On the basis of the design,a sample was produced and measured.The practical measurement results show that using structure light guide plate,the contrast ratio turns from 6.01 to 6.01 as compared with the common light guide plate.These results satisfy the requirements of local dynamic dimming.