中国塑料 ›› 2022, Vol. 36 ›› Issue (5): 81-88.DOI: 10.19491/j.issn.1001-9278.2022.05.014

• 加工与应用 • 上一篇    下一篇

偏光片变色机理浅析

周文贤()   

  1. 佛山纬达光电材料股份有限公司,广东 佛山 528136
  • 收稿日期:2021-11-30 出版日期:2022-05-26 发布日期:2022-05-26
  • 通讯作者: 周文贤(1983—),女,高级化工工程师,从事偏光片开发,sunny@winda.cn
    E-mail:sunny@winda.cn
  • 基金资助:
    佛山市科技创新项目(FS0AA?KJ419?4404?0102)

Analysis of discoloration mechanisms of polarizer

ZHOU Wenxian()   

  1. WINDA Opto?Electronics Co,Ltd,Foshan 528136,China
  • Received:2021-11-30 Online:2022-05-26 Published:2022-05-26
  • Contact: ZHOU Wenxian E-mail:sunny@winda.cn

摘要:

研究了太阳照射后液晶显示器(LCD)偏光片的变色现象,采用智能型氙灯老化试验机、广角/小角X射线散射结构分析仪(WAXS)、X?射线能量色散谱仪(EDS)和分光光度计等对偏光片的光学性能、耐候性能及表面元素等进行了测试和表征,并探讨了其变色机理。结果表明,105 ℃×1 h的高温测试后,聚乙烯醇(PVA)膜素子中I3-紫外吸收峰强度增加1倍;120 ℃×120 h测试后,I3-紫外吸收峰强度增加2倍,PVA?I5-吸收峰强度减弱,PVA?I3-吸收峰强度增加;碘系偏光片变色机理为PVA?I5-向PVA?I3-转化,随着I3-含量增加偏光片颜色逐步变成棕色;变色的碘系偏光片在高温高湿处理后可以恢复到原来的颜色,PVA?I5-与PVA?I3-之间在偏光片中可以互相转换;偏光片受太阳辐射变色问题与偏光片抗紫外性能及耐高温性能有关;通过优化偏光片原料与制造工艺以提高其中紫外吸收剂含量可以提升其抗紫外性能;增加偏光片中PVA?I5-含量以提升其耐高温性能可以解决太阳照射下碘系偏光片变色问题。

关键词: 碘, 偏光片, 氙灯测试, 高温, 变色, 太阳照射

Abstract:

The discoloration of the polarizer of liquid crystal displays after solar irradiation was analyzed, and its optical properties, weather resistance, surface elements and of discoloration mechanism were investigated using an intelligent xenon lamp aging tester, a wide?angle/small?angle X?ray scattering applause, an X?ray energy dispersive spectrometer, and a spectrophotometer. The results indicated that the peak intensity of UV absorption for I3- was doubled after exposed to 105 oC for 1 h, and its peak intensity increased by a factor of 3 after exposed to 120 oC for 120 h. However, and the peak intensity of UV absorption for PVA?I5- decreased, whereas the peak intensity for PVA?I3- increased. The discoloration mechanism of the iodine?based polarizer was attributed to the molecular structure conversion from PVA?I5- to PVA?I3-. With an increase in test time at a high temperature, the color of the polarizer gradually changed to brown as the ratio of I3- increased. Meanwhile, the color of the discolored polarizer could recover after a high?temperature and high?humidity treatment. A conversion between the PVA?I5- and PVA?I3- could be operated mutually in the polarizer. The solar radiation discoloration of the polarizer was mainly affected by the anti?ultraviolet performance and high?temperature resistance of the polarizer. The anti?purple performance of the polarizer could be improved by increasing the content of UV absorber through optimizing the raw materials and manufacturing process, and its high temperature resistance could be improved by increasing the content of PVA?I5-. This can solve the problem of discoloration of the iodine?based polari?zers under sunlight.

Key words: iodine, polarizer, xenon lamp test, high temperature, discoloration, sun exposure

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