窄长型车载液晶显示屏黑画面漏光研究及改善

Research and improvement of black screen light leakage in narrow-length automotive display

黑画面的漏光是高级超维场开关显示模式(Advanced-Super Dimensional Switching,ADS)TFT-LCD中常见的一种不良,当液晶面板有形变或应力作用即容易发生漏光不良,窄长型ADS车载产品更容易受力形变。本文探讨漏光发生的机理并进行改善。研究发现,面板由于形变,内应力,液晶偏转发生异常,最终导致黑画面的漏光。本文以312.4mm(12.3in)寸窄长型车载ADS产品为例,首先对平坦度进行分析:从面板平坦度、背光源平坦度、背光源口子胶位置等方面分析。再从应力着手:从模组将集成电路压接在玻璃基板上的工艺(Chip on Glass,COG)、面板和背光源的组装精度进行漏光实验。实验结果表明,在面板平坦度提升、背光源平坦度管控、背光源口子胶设计为半口子胶并由长边固定变更为短边固定,COG绑定温度和压力进行实验设计、组装精度提升等方面改善后,黑画面漏光可从15%降低至0.1%以内。

Black light leakage is a common in advanced-super dimensional switching(ADS)mode TFT-LCD product.It is easy to cause light leakage when the panel has deformation or internal stress,especially for narrow-length products.This article discussed the reason of light leakage and improve it.It is found that the panel deformation,internal stress,and liquid crystal deflection are abnormal,which can lead to light leakage.For example,this paper discusses 312.4 mm(12.3 in)ADS automotive product.At first,for flatness:we analyzed the panel flatness,backlight flatness and the location of backlight tape.Second,for internal stress:we analyzed COG(Chip on Glass)technology,assembly accuracy of panel and backlight.Light leakage experiments show that improvement of panel flatness,backlight flatness and assembly accuracy can reduce the level of leakage.Other factors,such as cutting the length of backlight tape and changing its position from long side to short side,controlling COG bonding temperature and pressure with DOE(Design of Experiment)are also effective.All the above measures,light leakage can be reduced from 15%to less than 0.1%.