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Color filter

  • US 4,416,514 A
  • Filed: 11/10/1980
  • Issued: 11/22/1983
  • Est. Priority Date: 11/10/1980
  • Status: Expired due to Term
First Claim
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1. A filter for varying the spectral composition of visible light, said filter comprising:

  • a plurality of different dichroic polarizers stationed along an optical path to intercept light traveling therealong, each of said dichroic polarizers structured for selectively plane polarizing a different part of the visible spectrum while transmitting the remainder of the visible spectrum unpolarized;

    a plane polarizer stationed along said optical path for polarizing substantially uniformly all wavelengths of the visible spectrum; and

    a plurality of voltage responsive twisted nematic liquid crystals one for each of said dichroic polarizers, said twisted nematic liquid crystals being stationed along said optical path and structured for varying the rotation of linearly polarized light in accordance with the voltage applied thereto,said dichroic polarizers, said plane polarizer, and said twisted nematic liquid crystals being arranged along said optical path in a predetermined sequence and azimuthal orientation to modify the spectral content of visible light incident to said filter so that said filter transmits any one of a predetermined number of colors whose saturation and hue are related to the voltages applied to said twisted nematic liquid crystals.

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