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Liquid crystal color modulation displays with dyes of different orders and circuitry for providing modulated AC excitation voltage

  • US 5,289,301 A
  • Filed: 06/12/1992
  • Issued: 02/22/1994
  • Est. Priority Date: 06/12/1992
  • Status: Expired due to Fees
First Claim
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1. Liquid crystal display apparatus comprising:

  • (a) a transparent superstrate having an interior face and an exterior face,(b) a substrate parallel to and spaced from said superstrate, said substrate having an interior face and an exterior face,(c) a first transparent electrode secured to the interior face of said superstrate,(d) a second transparent electrode secured to the interior face of said substrate,(e) liquid crystal material interposed between said first and second electrodes,(f) a positive order parameter dye incorporated in said liquid crystal material,(g) a negative order parameter dye incorporated in said liquid crystal material,(h) first means to generate an operating voltage wave varying between 0 volts and a level above 0 volts and to vary the frequency of said voltage wave,(i) second means to generate a second voltage wave of a constant high frequency above the maximum frequency of said operating voltage wave,(j) third means to connect the operating voltage wave and the second voltage wave to said first and second electrodes,(k) whereby said operating voltage wave varies the color of the display between the full color of said positive order parameter dye and the full color of said negative order parameter dye and shades of color between the full colors of said positive order parameter dye and said negative order parameter dye,(l) and whereby said second voltage wave prevents degradation of said liquid crystal mixture.

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