Electra-Optic and Ionic Properties of Twisted Nematic Cells With Different Chiral Pitch

  • Kim, Sung-Woon (Hyundai Display Technology Incorporated. R&D Laboratory) ;
  • Park, Hee-Do (Hyundai Display Technology Incorporated. R&D Laboratory) ;
  • Kim, Hee-Cheol (Hyundai Display Technology Incorporated. R&D Laboratory) ;
  • Park, Young-Il (Hyundai Display Technology Incorporated. R&D Laboratory) ;
  • Suh, Dong-Hae (Hyundai Display Technology Incorporated. R&D Laboratory) ;
  • Lee, Won-Geon (Hyundai Display Technology Incorporated. R&D Laboratory) ;
  • Park, Hae-Sung (Hyundai Display Technology Incorporated. R&D Laboratory)
  • Published : 2002.08.21

Abstract

We investigated electro-optic and ionic properties of twisted nematic cells by using control of chiral pitch. These properties are observed in practical experiment and simulations. C-V and V-T curve characteristics were obtained from three types of cells with d/p. It is shown that d/p ratio of short cells exhibit faster response time improved by 20% than normal cell. Also, inter-gray response time is improved each rise time and decay time. And, the increase of saturation voltage is happened because of the small twist angel change from initial state at high voltage near 5V. To compensate for longer black level tail, gamma curve index was varied from g = 2.2 to g = 2.7 in module status. Additionally, adding chiral dopant into TN cells improved ionic characteristics such as increasing VHR, Ion density and DC Hysteresis were decreased..

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