Color filter
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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Abstract
A variable color filter comprising a plurality of differently colored diochroic polarizers, an equal number of voltage responsive twisted nematic liquid crystal cells, and a plane polarizer all arranged along an optical path in a predetermined manner to modify the spectral content of visible light incident to the filter so that the filter transmits any one of a predetermined number of colors whose saturation and hue are related to the voltages applied to the liquid crystal cells.
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Citations
31 Claims
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1. A filter for varying the spectral composition of visible light, said filter comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A filter for continuously varying the spectral composition of visible light, said filter comprising:
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a plurality of different dichroic polarizers stationed along an optical path to intercept light traveling therealong, each of said dichroic polarizers structured for 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 continuously from 0-degrees to 90-degrees 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 gamut of colored light whose saturation and hue are related to the voltages applied to said twisted nematic liquid crystals. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A filter for varying the spectral composition of visible light, said filter comprising:
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a plurality of different dichroic polarizers stationed along an optical path to intercept light traveling therealong, each of said dichroic polarizers structured for 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 rotating linearly polarized light between either one of two planes whose azimuths are separated by 90 degrees from one another in response to the application of said voltage 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 not to exceed the maximum possible combination of voltage states for said liquid crystals and whose saturation and hue are related to the combination of said twisted nematic liquid crystals to which said predetermined voltage is applied. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27)
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28. A filter for continuously varying the spectral composition of visible light, said filter comprising:
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a first dichroic polarizer stationed along an optical path to intercept light transmitted therealong, said first dichroic polarizer including a magenta dye and structured for plane polarizing green light while transmitting blue and red light unpolarized; first means stationed along said optical path adjacent said first dichroic polarizer for selectively varying the rotation of linearly polarized light continuously from 0-degrees to 90-degrees; a plane polarizer stationed adjacent said first means along said optical path for polarizing substantially uniformly all wavelengths of the visible spectrum; second means stationed along said optical path adjacent said plane polarizer for selectively varying the rotation of linearly polarized light continuously from 0-degrees to 90-degrees; a second dichroic polarizer stationed along said optical path adjacent said second means, said second dichroic polarizer including a cyan dye and structured to plane polarize red light while transmitting blue and green light unpolarized; third means stationed along said optical path adjacent said second dichroic polarizer for selectively varying the rotation of linearly polarized light continuously from 0-degrees to 90-degrees; and a third dichroic polarizer stationed along said optical path adjacent said third means, said third dichroic polarizer including a yellow dye and structured to plane polarize blue light while transmitting green and red light unpolarized, said dichroic polarizers, said plane polarizer and said first through third means being arranged along said optical path in a predetermined azimuthal orientation to modify the spectral content of visible light incident to said filter so that said filter transmits any one of a gamut of colored light whose saturation and hue are related to the angles through which said first through said third means are selected to rotate the plane of polarization of plane polarized light incident, respectively, thereto. - View Dependent Claims (29, 30, 31)
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Specification