材料期刊网

图像残像是评价画面质量的最重要因素之一,大部分工程师研究了组合物的材料和液晶面板的制造工艺,以改善影像残留,但之前的研究主要是以正性液晶材料为基础进行探讨的,本文主要以负性液晶材料为基础研究了用边缘场驱动的面板残像.首先为了比较正性液晶与负性液晶,测量了离子密度及电压保持率(VHR),其次为了比较两种配向材料(PI)与液晶材料的搭配特性并选择合适的组合,量测了样品的直流残留(RDC)电压和Vcom电压随时间的变化.从量测结果可知,紫外(UV)光照前负性液晶离子密度是正性液晶的39倍,经过紫外光照,后负性液晶的离子密度为560 Pc/cm,且其紫外光照后电压保持率变化量为2．7％；使用负性液晶搭配 PI1的样品 A-1的直流残留电压和Vcom (等效为交流驱动电压的中心值)随时间变化量都是最大的,分别为0．5 V和250 mV,负性液晶搭配PI2材料的面板和正性液晶的面板的直流残留电压均小于0．2 V,其Vcom随时间变化量均在50 mV以内.负性液晶材料的离子浓度含量高,且其稳定性比正性液晶材料差,负性液晶材料比正性液晶材料更容易发生残像；对于使用负性液晶材料,边缘场驱动模式的面板,搭配 PI2配向膜材料能够保持低的直流残留电压及低的Vcom电压变化量,从而对改善残像现象有帮助.

Image sticking is one of the most important factors to evaluate the display quality of liquid crystal display(LCD),and most of the engineers studied the material composition and the LCD manu-facturing process to improve the image sticking,but the previous research mostly based on the posi-tive liquid crystal material.In this paper,the image sticking is mainly focused on the negative liquid crystal(LC)material which is driven by fringe electric field.First,the ion density and VHR are meas-ured to compare the stability of the two kinds of LC material,and then the residual DC voltage and theVcom voltage shift of the sample are measured to compare the characteristics of the negative LC with two PI materials so as to select the right combination.The experimental results show that the ion density of the negative LC is 3 9 times as much as the positive LC before UV curing.After UV curing, its ion density is 560 Pc/cm and its VHR variation is 2.7%;the residual DC voltage and theVcom volt-age shift with time of sample A-1 are the largest which use negative LC with PI1 .Its residual DC volt-age is 0.5 V and theVcom voltage shift is 250 mV,and the residual DC voltage of samples which use negative LC with PI2 and positive LC are less than 0.2 V,of which the Vcom variation with time are within 50 mV.The ion density of negative LC material is high,and its stability is worse than positive LC material,image sticking appears in the negative LC material more likely.For the FFS driving mode LCD panel which using negative liquid crystal materials,it is beneficial to use the PI2 material to maintain a low residual DC voltage and low Vcom voltage variation,which are helpful to improve the image sticking.