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Apparatus and method for an electronically controlled color filter for use in information display applications

  • US 5,032,007 A
  • Filed: 04/07/1988
  • Issued: 07/16/1991
  • Est. Priority Date: 04/07/1988
  • Status: Expired due to Term
First Claim
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1. A color filter for controlling transmission of applied light to provide a selected output color signal, said color filter comprising:

  • a first filter includinga first dye material cell having an absorption coefficient in a first preselected spectral range, said first dye material absorption coefficient determined by an electric field strength applied thereto,first electrodes positioned to apply an electric field to said first dye material having an electric field strength determined by a first voltage applied across said first electrodes;

    a first neutral density polarizer positioned between said applied light and said first filter;

    a second filter includinga second dye material cell having an absorption coefficient in a second preselected spectral range, said second dye material absorption coefficient determined by an electric field strength applied thereto,second electrodes positioned to apply an electric field to said first dye material having an electric field strength determined by a second voltage applied across said second electrodes;

    a second neutral density polarizer positioned between said first filter and said second filter, said second polarizer being aligned with said first polarizer;

    a third filter includinga third dye material cell having an absorption coefficient in a third preselected spectral range determined by an electric field strength applied thereto,third electrodes positioned to apply an electric field to said third dye material having an electric field strength determined by a third voltage applied across said third electrodes;

    a third neutral density polarizer coupled between said second filter and said third filter, said third polarizer aligned with said first polarizer; and

    voltage means for providing said first, second and third voltages resulting in said selected output color signal, wherein said color filter includes a multiplicity of sets of aligned first, second and third cells;

    each set of aligned cells controlling transmission of light in a preselected region of said filter, each of said preselected display regions being a pixel region, said transmitted light providing a projection display.

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