Color display

Claim 2

In a color display system that includes first and second portions in stacked arrangement with a polarizer interposed therebetween, each of said portions including a liquid crystal cell, an improvement wherein each of the cells is of the supertwisted nematic type and exhibits a total twist angle greater than or equal to 180° and less than 360°, and the portions are tuned to provide different spectral responses.

Claim 5

The method of claim 2 in which the dynamic signal applied to the first assembly changes periodically among more than two values, thereby producing more than two distinct birefringent effects.

Claim 6

A color display comprising: first and second optical assemblies, each of the assemblies including a plurality of pixels, each of the pixels being independently operable to birefringently control passage of a portion of a spectrum of light passing therethrough; a first polarizer interposed between the optical assemblies; and second and third polarizers sandwiched about the optical assemblies; wherein at least one of the second or third polarizers is dyed a color selected from the group cyan, magenta and yellow.

Claim 7

A color display comprising: first and second optical assemblies, each of the assemblies including a plurality of pixels, each of the pixels being independently operable to birefringently control passage of a portion of a spectrum of light passing therethrough; a first polarizer interposed between the optical assemblies; and second and third polarizers sandwiched about the optical assemblies; wherein at least one of the second or third polarizers is dyed a color selected from the group cyan, magenta and yellow.

Claim 8

In a color display method in which first and second optical elements are stacked and pixels thereof individually operated, the pixels of the first optical element being controllably operated to subtract light of a first color from light passing therethrough, the pixels of the second optical element being controllably operated to subtract light of a second color different than the first from light passing therethrough, an improvement comprising: providing birefringent optical elements as the first and second optical elements, each of said birefringent optical elements exhibiting a birefringent effect which varies in response to a signal applied thereto, the first birefringent optical element exhibiting a deleterious spectral property whereby its transmission at the second color is a function of the signal applied thereto, thereby rendering light transmission though the stack at the second color a function of both the signal applied to the second optical element and the signal applied to the first optical element; and decoupling control of the second color from the first optical element by operating the first optical element in conjunction with a polarizer dyed to pass light of the second color orthogonal to a polarization axis thereof, thereby causing the first optical element to bleed the second color and minimizing the correlation between transmission of light of the second color and the signal applied to the first optical element.

Claim 9

In a color display method in which first and second optical elements are stacked and pixels thereof individually operated, the pixels of the first optical element being controllably operated to subtract light of a first color from light passing therethrough, the pixels of the second optical element being controllably operated to subtract light of a second color different than the first from light passing therethrough, an improvement comprising: providing birefringent optical elements as the first and second optical elements, each of said birefringent optical elements exhibiting a birefringent effect which varies in response to a signal applied thereto, the first birefringent optical element exhibiting a deleterious spectral property whereby its transmission at the second color is a function of the signal applied thereto, thereby rendering light transmission though the stack at the second color a function of both the signal applied to the second optical element and the signal applied to the first optical element; and decoupling control of the second color from the first optical element by operating the first optical element in conjunction with a polarizer dyed to pass light of the second color orthogonal to a polarization axis thereof, thereby causing the first optical element to bleed the second color and minimizing the correlation between transmission of light of the second color and the signal applied to the first optical element.

Claim 10

In a color display that includes entrance and exit polarizers and that can be operated to yield at least the colors black, white, red, green, blue, cyan, yellow and magenta, an improvement wherein the display includes at least two stacked birefringent subassemblies, each of the subassemblies defining a plurality of pixels, each of said pixels being independently operable to birefringently control passage of a portion of a spectrum of light passing therethrough.

Claim 11

In a color display that includes entrance and exit polarizers and that can be operated to yield at least the colors black, white, red, green, blue, cyan, yellow and magenta, an improvement wherein the display includes at least two stacked birefringent subassemblies, each of the subassemblies defining a plurality of pixels, each of said pixels being independently operable to birefringently control passage of a portion of a spectrum of light passing therethrough.

Claim 12

An accessory for use with a conventional overhead projector to project electronically generated color images therefrom, the projector having a bulb, a projection lens, and a projection surface having a Fresnel lens thereunder, the Fresnel lens focusing light from the bulb into the projection lens, the accessory being adapted to rest on the projection surface and comprising: first lens means for receiving converging white light from the projection surface of the projector and collimating said light; second lens means for receiving collimated light and focusing said light into the projection lens; a display assembly positioned between the first and second lens means and illuminated by the collimated light, said subassembly including first, second, third and fourth polarizers and further including first, second and third birefringent display subassemblies, each including a liquid crystal display panel, the birefringence of said display subassemblies being tuned, respectively, to first, second and third subtractive complementary colors, each of said panels defining a plurality of electronically operable pixels, said panels being stacked so that corresponding pixels in each of said panels are aligned with the direction of the collimated light, the first panel being positioned between the first and second polarizers, the second panel being positioned between the second and third polarizers and the third panel being positioned between the third and fourth polarizers.

Claim 13

An accessory for use with a conventional overhead projector to project electronically generated color images therefrom, the projector having a bulb, a projection lens, and a projection surface having a Fresnel lens thereunder, the Fresnel lens focusing light from the bulb into the projection lens, the accessory being adapted to rest on the projection surface and comprising: first lens means for receiving converging white light from the projection surface of the projector and collimating said light; second lens means for receiving collimated light and focusing said light into the projection lens; a display assembly positioned between the first and second lens means and illuminated by the collimated light, said subassembly including first, second, third and fourth polarizers and further including first, second and third birefringent display subassemblies, each including a liquid crystal display panel, the birefringence of said display subassemblies being tuned, respectively, to first, second and third subtractive complementary colors, each of said panels defining a plurality of electronically operable pixels, said panels being stacked so that corresponding pixels in each of said panels are aligned with the direction of the collimated light, the first panel being positioned between the first and second polarizers, the second panel being positioned between the second and third polarizers and the third panel being positioned between the third and fourth polarizers.

Claim 14

The accessory of claim 7 in which: one of the panels is yellow; one of the panels is cyan; one of the panels is magenta; the colors of the first and fourth polarizers are selected from the list: yellow, cyan, magenta and black; and the colors of the second and third polarizers are selected from the list: red, green, blue and black; wherein at least two of the polarizers are colored a color other than black.

Claim 15

A color display assembly comprising first, second, third and fourth polarizers and further including first, second and third birefringent display subassemblies, each including a supertwisted nematic liquid crystal display panel, the birefringence of said display subassemblies being tuned, respectively, to first, second and third subtractive complementary colors, each of said panels defining a plurality of electronically operable pixels, said panels being stacked so that corresponding pixels in each of said panels are optically aligned, the first panel being positioned between the first and second polarizers, the second panel being positioned between the second and third polarizers and the third panel being positioned between the third and fourth polarizers.

Claim 16

A color display assembly comprising first, second, third and fourth polarizers and further including first, second and third birefringent display subassemblies, each including a supertwisted nematic liquid crystal display panel, the birefringence of said display subassemblies being tuned, respectively, to first, second and third subtractive complementary colors, each of said panels defining a plurality of electronically operable pixels, said panels being stacked so that corresponding pixels in each of said panels are optically aligned, the first panel being positioned between the first and second polarizers, the second panel being positioned between the second and third polarizers and the third panel being positioned between the third and fourth polarizers.

Claim 19

The method of claim 10 which further includes tuning the first and second assemblies so that the pixels included therein birefringently control different portions of the optical spectrum.

Claim 20

In a stacked cell electroptic display, an improvement comprising use of both a primary color cell and a subtractive primary color cell in cooperative relationship.

Claim 21

In a stacked cell electroptic display, an improvement comprising use of both a primary color cell and a subtractive primary color cell in cooperative relationship.

Claim 22

In an electroptic display using a color mosaic filter comprised of a plurality of filter elements of at least two colors, an improvement comprising passing blue light through all of the mosaic filter elements.

Claim 23

In an electroptic display using a color mosaic filter comprised of a plurality of filter elements of at least two colors, an improvement comprising passing blue light through all of the mosaic filter elements.

Claim 24

A display method comprising: illuminating two optical paths with illumination comprised of first, second and third primary light colors; in the first path: selectively attenuating light of the first color; selectively attenuating light of both the second and third colors; and attenuating light of the second color; and in the second path; selectively attenuating light of the first color; selectively attenuating light of both the second and third colors; and attenuating light of the third color.

Claim 25

A display method comprising: illuminating two optical paths with illumination comprised of first, second and third primary light colors; in the first path: selectively attenuating light of the first color; selectively attenuating light of both the second and third colors; and attenuating light of the second color; and in the second path; selectively attenuating light of the first color; selectively attenuating light of both the second and third colors; and attenuating light of the third color.

Claim 26

A color display system comprising a color mosaic filter stacked with first and second color liquid crystal display panels, wherein the first liquid crystal display panel defines a uniform array of pixels of a first size, and the second liquid crystal display panel defines a uniform array of pixels of a second size larger than the first, and the first and second panels are stacked so that each of the pixels of the second panel is optically superimposed over a plurality of pixels in the first panel.

Claim 27

A color display system comprising a color mosaic filter stacked with first and second color liquid crystal display panels, wherein the first liquid crystal display panel defines a uniform array of pixels of a first size, and the second liquid crystal display panel defines a uniform array of pixels of a second size larger than the first, and the first and second panels are stacked so that each of the pixels of the second panel is optically superimposed over a plurality of pixels in the first panel.

Claim 28

A color display system comprising a color mosaic filter stacked with first and second LCD subassemblies; the mosaic filter including alternating pixels of first and second different colors selected from the subtractive primary colors: yellow, cyan, magenta; each of said subassemblies defining a plurality of electronically operable pixels, the birefringence of the pixels in the first subassembly being tuned to the subtractive primary color not included in the pixels of the color mosaic filter, the birefringence of the pixels in the second subassembly being tuned to a primary color complementary to the subtractive primary color of the first subassembly.

Claim 29

A color display system comprising a color mosaic filter stacked with first and second LCD subassemblies; the mosaic filter including alternating pixels of first and second different colors selected from the subtractive primary colors: yellow, cyan, magenta; each of said subassemblies defining a plurality of electronically operable pixels, the birefringence of the pixels in the first subassembly being tuned to the subtractive primary color not included in the pixels of the color mosaic filter, the birefringence of the pixels in the second subassembly being tuned to a primary color complementary to the subtractive primary color of the first subassembly.