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Dichroic liquid crystal display with integral electroluminescent backlighting

  • US 5,121,234 A
  • Filed: 10/29/1990
  • Issued: 06/09/1992
  • Est. Priority Date: 10/29/1990
  • Status: Expired due to Term
First Claim
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1. An electro-optical display device for control of light transmission, comprising:

  • electro-optical cell means including liquid crystal fluid means disposed between first and second dielectric plate means, each of said first and second plate means being optically transmissive, and said first one of said plate means having electrically conductive optically transmissive portions at a surface facing said liquid crystal means,electroluminescent film means disposed on said second one of said plate means and distal to said electrically conductive portions,third dielectric plate means having first and second planar surfaces and comprising conductive optically reflective electrode means superimposed upon one of said planar surfaces proximal to said electroluminescent film means,said liquid crystal fluid means and said electro-luminescent film means being responsive to a source of electric power for producing an electric field, and cooperating such that selective energization of said electrically conductive portions of said one of said plate means causes corresponding selective energization of portions of said electroluminescent film means superimposed on said energized electrically conductive portions of said one of said plate means, and further causes selective energization of corresponding areas of said liquid crystal fluid means to a mode of light transmissibility, so that said energized transmissive areas of said liquid crystal fluid means transmit light emitted from said energized portions of electro-luminescent film means, while the deenergized portions of said electroluminescent film means do not emit light, thereby combining with said deenergized portions of said liquid crystal film means to provide enhanced contrast of said electro-optical display device.

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