反射式液晶黑点缺陷分析与改善

Analysis and Improvement of Black Spot Defects of Reflective Liquid Crystal

采用超景深显微镜、扫描电镜、能谱仪等手段对存在黑点缺陷的反射式液晶进行分析。结果表明:黑点为偏光片反射膜Al层被腐蚀的坑洞,并存在I元素残留,且I元素含量越高,腐蚀程度越严重。通过双85老化试验能快速复现故障,分析为PVA膜吸附的I发生高温升华,并渗透穿过TAV膜,与反射膜Al层接触,在H_(2)O催化作用下发生氧化还原反应生成AlI_(3),导致反射膜Al层腐蚀;增大碘溶液浓度及染色时间,并提高PVA膜拉伸倍率,以增强I元素在PVA膜上的吸附能力,可有效提高液晶的质量可靠性。

The black spot defects of liquid crystal were studied and analyzed by means of super-depth-of-field microscopy,scanning electron microscopy and energy disperse spectroscopy.The results show that the black spots are corrosion pits in the Al layer of the reflective film of the polarizer,with the residue of I element.The higher the content of I element,the more serious the corrosion is.Through double 85 aging test,the defects can be quickly reproduced.The analysis shows that I_(2) adsorbed by PVA film sublimates at high temperature,penetrates through TAV film and contacts with the Al layer of the reflective film.Under the catalysis of H_(2)O,redox reaction occurs to generate AlI_(3),leading to the corrosion of the Al layer of the reflective film.Increasing the concentration of I_(2) solution and dyeing time as well as increasing the tensile ratio of PVA film can enhance the adsorption capacity of I element on PVA film,which can effectively improve the quality and reliability of liquid crystal.