Dichroic liquid crystal display with integral electroluminescent backlighting
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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Abstract
A composite liquid crystal electroluminescent electro-optical display device utilizing single-cell construction. Backlighting is furnished by a low-intensity, low-power-consumption integrally formed electroluminescent light source cooperating with a liquid crystal element with commonly excited electrodes. The integral electro-luminescent light source replaces the requirement for a transflector. The invention offers substantially improved contrast while minimizing physical size, power dissipation and construction complexity.
87 Citations
13 Claims
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1. An electro-optical display device for control of light transmission, comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An electro-optical display device for control of light transmission, comprising:
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electro-optical cell means including liquid crystal fluid means responsive to a source of electrical excitation for forming alphanumeric characters, and electroluminescent cell means superposed on said electro-optical cell means, portions thereof selectively responsive to said source of electrical excitation, said electro-optical cell means and said electro-luminescent cell means provided with electrodes cooperating when activated by said source of electrical excitation to form a common alphanumerical character characterized by light emissions from said electroluminescent cell means in regions preferentially electrically excited and by the absence of light emissions from regions which have not been electrically excited.
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11. An electro-optical display device for control of light transmission, comprising:
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electro-optical cell means including liquid crystal fluid means disposed between first and second dielectric plate means, each of said first and second dielectric plate means being optically transmissive, and said first dielectric plate means having electrically conductive optically transmissive discrete portions at a surface facing said liquid crystal means, electroluminescent cell means superposed on said electro-optical cell means and including third dielectric plate means having first and second planar surfaces and comprising optically transmissive discrete electrically conductive electrode means superimposed upon one of said planar surfaces distal to said electro-optical cell means, said discrete electrode portions of said electro-luminescent cell means being aligned with corresponding portions of said electro-optical cell means, said electroluminescent cell means further comprising electroluminescent film means disposed on said third dielectric plate means and on said distally superimposed electrically conductive electrode means, and fourth dielectric plate means comprising an optically reflective electrically conductive electrode means superposed on said film means, said electro-optical cell 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 corresponding electrically conductive portions of said one of said first and third dielectric plate means causes corresponding energization of portions of said electroluminescent film means superimposed thereon, 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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12. An electro-optical display device for control of light transmission, comprising:
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electro-optical cell means including liquid crystal fluid means disposed between first and second dielectric plate means, each of said first and second dielectric plate means being optically transmissive, and each of said dielectric plate means having corresponding electrically conductive optically transmissive discrete portions, one plurality of said discrete portions being disposed on said first dielectric plate means at a surface facing said liquid crystal means, and a corresponding plurality of said discrete portions being disposed on said second dielectric plate means at a surface opposing said liquid crystal means, electroluminescent film means superposed on said second dielectric plate means on said opposing surface, and third dielectric plate means comprising optically reflective electrically conductive electrode means superposed on said film means, said electro-optical cell 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 dielectric plate means causes corresponding energization of portions of said electroluminescent film means superimposed thereon, 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 electroluminescent 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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13. A method for enhancing light transmission in an electro-optical display device, comprising the steps of:
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providing an electro-optical cell having a pair of spaced plates, each of said pair being transparent to light, dichroic nematic liquid crystal means disposed between said plates, a first one of said plates having a plurality of electrically conductive means for selectively enabling an electrical field to be applied across said liquid crystal means, such that the molecules of said liquid crystal means are preferentially aligned to permit light transmission through predetermined portions of said plates, providing an electroluminescent cell cooperating with said electro-optical cell and said electrical field, said electroluminescent cell having a layer of electroluminescent material disposed to illuminate said electro-optical cell in alignment with said predetermined portions of said plates, and a layer of reflective, electrically conductive material opposing said electroluminescent layer, for enabling said electrical field to be applied to said electro-optical cell and to said electroluminescent layer, and for reflecting incident light to return through said electro-optical cell, and providing to at least a portion of said electrically conductive means and said layer of conductive material an electric field across at least a portion of said liquid crystal means, for changing the orientation of said liquid crystal molecules comprising said liquid crystal means, such that light from said electroluminescent layer is selectively transmitted through a region of said liquid crystal means wherein said molecules have been reoriented and substantially no light is transmitted through regions which have not been molecularly reoriented.
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Specification