US5751384A — Color polarizers for polarizing an additive color…

Claim 1

Independent Claim 76 words

A complementary color polarizer comprising: a first linear polarizer; and a first retarder stack comprising two or more retarders, said first retarder stack positioned in series with said polarizer, wherein the number, N, of said retarders and the retardances and orientations of said retarders are such that a first additive primary color spectrum is transmitted along a first polarization axis and the complementary first subtractive primary color spectrum is transmitted along a second, orthogonal, polarization axis.

Claim 2

Dependent Claim 76 words

A complementary color polarizer comprising: a first linear polarizer; and a first retarder stack comprising two or more retarders, said first retarder stack positioned in series with said polarizer, wherein the number, N, of said retarders and the retardances and orientations of said retarders are such that a first additive primary color spectrum is transmitted along a first polarization axis and the complementary first subtractive primary color spectrum is transmitted along a second, orthogonal, polarization axis.

Claim 3

Dependent Claim 34 words

The color polarizer of claim 1 wherein the number of said retarders and the retardances and orientations of said retarders are such that said first additive primary color spectrum is an approximate square wave.

Claim 4

Dependent Claim 29 words

The color polarizer of claim 2 wherein said approximate square wave contains more than one transmission maximum and within the pass-band more than one transmission minimum within the stop-band.

Claim 5

Dependent Claim 21 words

The color polarizer of claim 3 wherein the transition band slope of said approximate square wave is less than 70 nm.

Claim 6

Dependent Claim 16 words

The color polarizer of claim 3 wherein said transition band slope is less than 50 nm.

Claim 7

Dependent Claim 29 words

The color polarizer of claim 3 wherein said approximate square wave contains more than two transmission maxima within the pass-band and more than two transmission minima within the stop-band.

Claim 8

Dependent Claim 26 words

The color polarizer of claim 1 wherein the number of said retarders and the retardances and orientations of said retarders are based on a Solc design.

Claim 9

Dependent Claim 28 words

The color polarizer of claim 7 wherein said retarders are half-wave retarders and wherein the orientations of said retarders alternate in sign between +α and -αa, where α=π/4N.

Claim 10

Dependent Claim 13 words

The color polarizer of claim 8 wherein said retarders are multi-order half-wave retarders.

Claim 11

Dependent Claim 29 words

The color polarizer of claim 7 wherein said retarders are full-wave retarders and wherein the orientations of said retarders are α, 3α, 5α, . . . (2N-1)α, where α=π/4N.

Claim 12

Dependent Claim 13 words

The color polarizer of claim 10 wherein said retarders are multi-order full-wave retarders.

Claim 13

Dependent Claim 14 words

The color polarizer of claim 7 wherein N is between 2 and 4, inclusive.

Claim 14

Dependent Claim 12 words

The color polarizer of claim 1 wherein said retarders have equal retardance.

Claim 15

Dependent Claim 26 words

The color polarizer of claim 1 wherein the number of said retarders and the retardances and orientations of said retarders are based on a split-element design.

Claim 16

Dependent Claim 8 words

The color polarizer of claim 14 wherein N=3.

Claim 17

Dependent Claim 28 words

The color polarizer of claim 15 wherein the first retarder has orientation ±π/4, the second retarder has orientation 0 or π/2, and the third retarder has orientation ±π/4.

Claim 18

Dependent Claim 17 words

The color polarizer of claim 16 wherein said first retarder is oriented perpendicular to said third retarder.

Claim 19

Dependent Claim 42 words

The color polarizer of claim 17 wherein said first retarder has retardance Γ 1 +π/2, said second retarder has retardance Γ 2 +π, and said third retarder has retardance Γ 1 +π/2, where Γ 1 is approximately equal to Γ 2 .

Claim 20

Dependent Claim 38 words

The color polarizer of claim 17 wherein said first retarder has retardance Γ 1 +π/2, said second retarder has retardance Γ 2 +, and said third retarder has retardance Γ 1 +π/2, where 0<|Γ 1 -Γ 2 |<π/4.

Claim 21

Dependent Claim 17 words

The color polarizer of claim 16 wherein said first retarder is oriented parallel to said third retarder.

Claim 22

Dependent Claim 38 words

The color polarizer of claim 20 wherein said first retarder has retardance Γ 1 +π/2, said second retarder has retardance Γ2, and said third retarder has retardance Γ 1 +π/2, where Γ 1 is approximately equal to Γ2.

Claim 23

Dependent Claim 38 words

The color polarizer of claim 20 wherein said first retarder has retardance Γ 1 +π/2, said second retarder has retardance r 2 , and said third retarder has retardance Γ 1 +π/2, where 0<|Γ 1 - 2 |<π/4.

Claim 24

Dependent Claim 26 words

The color polarizer of claim 1 wherein the number of said retarders and the retardances and orientations of said retarders are based on a double-split-element design.

Claim 25

Dependent Claim 8 words

The color polarizer of claim 23 wherein N=5.

Claim 26

Dependent Claim 42 words

The color polarizer of claim 24 wherein the first retarder has orientation ±π/4, the second retarder has orientation 0 or π/2, the third retarder has orientation ±π/4, the fourth retarder has orientation 0 or π/2, and the fifth retarder has orientation ±π/4.

Claim 27

Dependent Claim 29 words

The color polarizer of claim 25 wherein said first retarder is oriented perpendicular to said fifth retarder and wherein said second retarder is oriented perpendicular to said fourth retarder.

Claim 28

Dependent Claim 44 words

The color polarizer of claim 26 wherein said first and fifth retarders each have retardance Γ 1 /2+π/2, said second and fourth retarders each have retardance Γ 1 +π/2, and said third retarder has retardance Γ 2 +π, where 0<|Γ 1 -Γ 2 |<π/8.

Claim 29

Dependent Claim 25 words

The color polarizer of claim 1 wherein the throughput of unpolarized light at the maximum of said first additive primary spectrum is greater than 35%.

Claim 30

Dependent Claim 13 words

The color polarizer of claim 28 wherein said throughput is greater than 40%.

Claim 31

Dependent Claim 23 words

A color polarizer comprising the color polarizer of claim 1 and further comprising a blocking filter positioned in series with said color polarizer.

Claim 32

Dependent Claim 68 words

The color polarizer of claim 30 wherein said blocking filter blocks a second additive primary color spectrum, wherein said second additive primary color spectrum in combination with a third additive primary color spectrum comprise said first subtractive primary color spectrum, whereby said first additive primary color spectrum is transmitted along said first polarization axis and said third additive primary color spectrum is transmitted along said second polarization axis.

Claim 33

Dependent Claim 16 words

The color polarizer of claim 1 wherein said first linear polarizer is a pleochroic color polarizer.

Claim 34

Dependent Claim 32 words

A color filter comprising the color polarizer of claim 1 and further comprising a first polarization separator, positioned on the opposite side of said first retarder stack from said first linear polarizer.

Claim 35

Dependent Claim 52 words

The color filter of claim 33 wherein said first polarization separator is a first polarizing beam splitter, for separating a first beam polarized along said first polarization axis and having said first additive primary spectrum from a second beam polarized along said second polarization axis and having said first subtractive primary spectrum.

Claim 36

Dependent Claim 94 words

The color filter of claim 34 further comprising a second retarder stack positioned to receive said second beam, said second retarder stack comprising two or more retarders, wherein the number of said retarders and the retardances and orientations of said retarders are such that a second additive primary color spectrum is transmitted along a first polarization axis and a third additive primary color spectrum is transmitted along a second, orthogonal, polarization axis, wherein said second additive primary color spectrum in combination with said third additive primary color spectrum comprise said first subtractive primary spectrum.

Claim 37

Dependent Claim 27 words

The color filter of claim 35 further comprising a second polarization separator, positioned on the opposite side of said second retarder stack from said first polarization separator.

Claim 38

Dependent Claim 16 words

The color filter of claim 36 wherein said second polarization separator is a polarizing beam splitter.

Claim 39

Dependent Claim 51 words

The color filter of claim 35 wherein said first polarization separator is a switchable polarizer for switching between transmission of light polarized along said first polarization axis and having said first additive primary spectrum, and transmission of light polarized along said second polarization axis and, having said first subtractive primary spectrum.

Claim 40

Dependent Claim 39 words

The color filter of claim 38 wherein said switchable polarizer comprises a second linear polarizer oriented at 0 or π/2, and a first polarization switch, said polarization switch positioned between said first retarder stack and said second linear polarizer.

Claim 41

Dependent Claim 16 words

The color filter of claim 39 wherein said second linear polarizer is a pleochroic color polarizer.

Claim 42

Dependent Claim 63 words

The color filter of claim 40 wherein said pleochroic color polarizer polarizes light of said first additive primary color spectrum and of a second additive primary color spectrum but does not polarize light of a third additive primary color spectrum, wherein said second additive primary color spectrum in combination with said third additive primary color spectrum comprise said first subtractive primary color spectrum.

Claim 43

Dependent Claim 17 words

The color filter of claim 39 wherein said first polarization switch comprises a nematic liquid crystal cell.

Claim 44

Dependent Claim 31 words

The color filter of claim 42 wherein said nematic liquid crystal cell is selected from the group consisting of homogeneous nematic cells, π-cells and twisted nematic cells, and supertwisted nematic cells.

Claim 45

Dependent Claim 17 words

The color filter of claim 42 wherein said first polarization switch comprises two nematic liquid crystal cells.

Claim 46

Dependent Claim 17 words

The color filter of claim 39 wherein said first polarization switch comprises a smectic liquid crystal cell.

Claim 47

Dependent Claim 38 words

The color filter of claim 45 wherein said smectic liquid crystal cell is selected from the group consisting of homogeneously aligned SmC*, homogeneously aligned SmA*, surface-stabilized ferroelectric, distorted helix ferroelectric, antiferroelectric and achiral ferroelectric smectic liquid crystal cells.

Claim 48

Dependent Claim 34 words

The color filter of claim 45 wherein said smectic liquid crystal cell is a SmC* half-wave retarder having orientation switchable between a first orientation of 0 or π/2 and a second orientation of ±π/4.

Claim 49

Dependent Claim 38 words

The color filter of claim 45 wherein said first polarization switch comprises an achromatic compound half-wave retarder, said achromatic retarder having composite orientation switchable between a first orientation of 0 or π/2 and a second orientation of ±π/4.

Claim 50

Dependent Claim 50 words

The color filter of claim 48 wherein said achromatic retarder comprises a first passive half-wave retarder oriented at π/12, a second passive half-wave retarder oriented at π/12, and a liquid crystal half-wave retarder positioned between said first and second passive retarders, and having an orientation switchable between 5π/12 and 8π/12.

Claim 51

Dependent Claim 19 words

The color filter of claim 49 wherein said liquid crystal half-wave retarder is a homogeneously aligned SmC* half-wave retarder.

Claim 52

Dependent Claim 64 words

The color filter of claim 39 further comprising a third linear polarizer oriented at 0 or π/2 and positioned on the opposite side of said second linear polarizer from said first retarder stack, a second retarder stack, comprising two or more retarders and positioned between said second and third linear polarizers, and a second polarization switch, positioned between said second and third linear polarizers.

Claim 53

Dependent Claim 41 words

The color filter of claim 51 wherein the number of said retarders in said second retarder stack and the retardances and orientations of said retarders are such that said color filter is switchable between red, green, blue and off-state transmission spectra.

Claim 54

Dependent Claim 41 words

The color filter of claim 52 wherein said first and second polarization switches each comprise an achromatic compound half-wave retarder, said achromatic retarders having composite orientation switchable between a first orientation of 0 or π/2 and a second orientation of ±π/4.

Claim 55

Dependent Claim 52 words

The color filter of claim 53 wherein each of said achromatic retarders comprises a first passive half-wave retarder oriented at π/12, a second passive half-wave retarder oriented at π/12, and a liquid crystal half-wave retarder, positioned between said first and second passive retarders, and having an orientation switchable between 5π/12 and 8π/12.

Claim 56

Dependent Claim 22 words

A color display comprising the color filter of claim 52 and further comprising a monochrome display in series with said color filter.

Claim 57

Dependent Claim 14 words

The color display of claim 55 wherein said monochrome display comprises an emissive display.

Claim 58

Dependent Claim 22 words

The color display of claim 56 wherein said emissive display is selected from the group consisting of CRT, FED and AMEL displays.

Claim 59

Dependent Claim 14 words

The color display of claim 55 wherein said monochrome display comprises a modulator display.

Claim 60

Dependent Claim 21 words

The color display of claim 58 wherein said modulator display comprises a multipixel array of liquid crystal analog or binary shutters.

Claim 61

Dependent Claim 18 words

The color display of claim 58 wherein said modulator display comprises a multipixel array of digital mirror devices.

Claim 62

Dependent Claim 17 words

The color display of claim 55 comprising a multi-pixel array of the color filters of claim 54.

Claim 63

Dependent Claim 18 words

The color display of claim 55 further comprising electronic switching means for field sequential switching said color filter.

Claim 64

Dependent Claim 21 words

A digital camera comprising the color filter of claim 51 and further comprising a receiver in series with said color filter.

Claim 65

Dependent Claim 18 words

The digital camera of claim 63 further comprising electronic switching means for field sequential switching said color filter.

Claim 66

Dependent Claim 14 words

The digital camera of claim 63 wherein said receiver is a multiple element detector.

Claim 67

Dependent Claim 44 words

The digital camera of claim 63 wherein said first retarder stack comprises five retarders, each having retardance Γ where Γ is a fixed retardance, and wherein the orientations of the first through fifth retarders are about 45, -15, -15, 10 and 10 degrees, respectively.

Claim 68

Dependent Claim 45 words

The digital camera of claim 66 wherein said second retarder stack comprises six retarders, each having retardance Γ' there Γ' is a fixed retardance, and wherein the orientations of the first through sixth retarders are about 8.3, 18, 18, -3.7, -45 and -78 degrees, respectively.

Claim 69

Dependent Claim 24 words

The digital camera of claim 67 wherein Γ is a full-wave at about 600 nm and Γ' is a full-wave at about 643 nm.

Claim 70

Dependent Claim 21 words

The digital camera of claim 67 wherein said first and said second polarization switches each comprise a smectic liquid crystal cell.

Claim 71

Dependent Claim 42 words

The digital camera of claim 69 wherein said first and second polarization switches each comprise an achromatic compound half wave retarder, said achromatic retarder having composite orientation switchable between a first orientation of 0 or π/2 and a second orientation of ±π/4.

Claim 72

Dependent Claim 21 words

The digital camera of claim 67 wherein said first and said second polarization switches each comprise a nematic liquid crystal cell.

Claim 73

Dependent Claim 44 words

The color filter of claim 51 wherein said first retarder stack comprises five retarders, each having retardance Γ where Γ is a fixed retardance, and wherein the orientations of the first through fifth retarders are about 45, -15, -15, 10 and 10 degrees, respectively.

Claim 74

Dependent Claim 45 words

The color filter of claim 53 wherein said second retarder stack comprises six retarders, each having retardance Γ' where Γ' is a fixed retardance, and wherein the orientations of the first through sixth retarders are about 8.3, 18, 18, -3.7, -45 and -78 degrees, respectively.

Claim 75

Dependent Claim 24 words

The color filter of claim 73 wherein Γ is a full-wave at about 600 nm and Γ' is a full-wave at about 643 nm.

Claim 76

Dependent Claim 21 words

The color filter of claim 73 wherein said first and said second polarization switches each comprise a smectic liquid crystal cell.

Claim 77

Dependent Claim 41 words

The color filter of claim 75 wherein said first and second polarization switches each comprise an achromatic compound half-wave retarder, said achromatic retarder having composite orientation switchable between a first orientation of 0 or π/2 and a second orientation of ±π/4.

Claim 78

Dependent Claim 21 words

The color filter of claim 73 wherein said first and said second polarization switches each comprise a nematic liquid crystal cell.

Claim 79

Dependent Claim 66 words

A method of providing light switchable between three primary colors, comprising the steps of: providing the color filter of claim 51; impinging white light on said color filter; and switching said first and said second polarization switches; wherein the number of retarders in said first and second retarder stacks, and the retardances and orientations thereof are such that sail color filter switches between three primary colors.

Claim 80

Dependent Claim 15 words

The method of claim 78 wherein said three primary colors are red, green and blue.

Claim 81

Dependent Claim 22 words

A color display comprising the color filter of claim 38 and further comprising a monochrome display in series with said color filter.

Claim 82

Dependent Claim 44 words

The color filter of claim 38 wherein said first retarder stack comprises five retarders, each having retardance Γ where Γ is a fixed retardance, and wherein the orientations of the first through fifth retarders are about 45, -15, -15, 10 and 10 degrees, respectively.

Claim 83

Dependent Claim 31 words

The color filter of claim 81 wherein Γ is a full-wave at about 600 nm, whereby said first additive primary color is blue and said first subtractive primary color is yellow.

Claim 84

Dependent Claim 45 words

The color filter of claim 38 wherein said first retarder stack comprises six retarders, each having retardance Γ where Γ is a fixed retardance, and wherein the orientations of the first through sixth retarders are about 8.3, 18, 18, -3.7, -45 and -78 degrees, respectively.

Claim 85

Dependent Claim 31 words

The color filter of claim 83 wherein Γ is a full-wave at about 643 nm, whereby said first additive primary color is red and said first subtractive primary color is cyan.

Claim 86

Dependent Claim 21 words

A digital camera comprising the color filter of claim 38 and further comprising a receiver in series with said color filter.

Claim 87

Dependent Claim 14 words

The digital camera of claim 85 wherein said receiver is a multiple element detector.

Claim 88

Dependent Claim 24 words

The digital camera of claim 86 wherein said color filter is divided into two or more segments, each of said segments being independently switchable.

Claim 89

Dependent Claim 15 words

The digital camera of claim 86 further comprising imaging optics optically coupled to said receiver.

Claim 90

Dependent Claim 44 words

The digital camera of claim 85 wherein said first retarder stack comprises five retarders, each having retardance Γ where Γ is a fixed retardance, and wherein the orientations of the first through fifth retarders are about 45, -15, -15, 10 and 10 degrees, respectively.

Claim 91

Dependent Claim 31 words

The digital camera of claim 89 wherein Γ is a full-wave at about 600 nm, whereby said first additive primary color is blue and said first subtractive primary color is yellow.

Claim 92

Dependent Claim 45 words

The digital camera of claim 85 wherein said first retarder stack comprises six retarders, each having retardance Γ where Γ is a fixed retardance, and wherein the orientations of the first through sixth retarders are about 8.3, 18, 18, -3.7, -45 and -78 degrees, respectively.

Claim 93

Dependent Claim 31 words

The digital camera of claim 71 wherein Γ is a full-wave at about 643 nm, whereby said first additive primary color is red and said first subtractive primary color is cyan.

Claim 94

Dependent Claim 44 words

The color polarizer of claim 1 wherein said first retarder stack comprises five retarders, each having retardance Γ where Γ is a fixed retardance, and wherein the orientations of the first through fifth retarders are about 45, -15, -15, 10 and 10 degrees, respectively.

Claim 95

Dependent Claim 31 words

The color polarizer of claim 93 wherein Γ is a full-wave at about 600 nm, whereby said first additive primary color is blue and said first subtractive primary color is yellow.

Claim 96

Dependent Claim 41 words

The color polarizer of claim 1 wherein said first retarder stack comprises three retarders, the first through third retarders having retardances Γ, 2Γ and 2Γ, where Γ is a fixed retardance, and having orientations about 45, -15, and 10 degrees, respectively.

Claim 97

Dependent Claim 31 words

The color polarizer of claim 95 wherein Γ is a full-wave at about 600 nm, whereby said first additive primary color is blue and said first subtractive primary color is yellow.

Claim 98

Dependent Claim 45 words

The color polarizer of claim 1 wherein said first retarder stack comprises six retarders, each having retardance Γ where Γ is a fixed retardance, and wherein the orientations of the first through sixth retarders are about 8.3, 18, 18, -3.7, -45 and -78 degrees, respectively.

Claim 99

Dependent Claim 31 words

The color polarizer of claim 97 wherein Γ is a full-wave at about 643 nm, whereby said first additive primary color is red and said first subtractive primary color is cyan.

Claim 100

Dependent Claim 45 words

The color polarizer of claim 1 wherein said first retarder stack comprises five retarders the first through fifth retarders having retardances Γ, 2Γ, Γ, Γ and Γ, where Γ is a fixed retardance, and having orientations about 8.3, 18, -3.7, -45 and -78 degrees, respectively.

Claim 101

Dependent Claim 31 words

The color polarizer of claim 99 wherein Γ is a full-wave at about 643 nm, whereby said first additive primary color is red and said first subtractive primary color is cyan.

Claim 102

Dependent Claim 29 words

The color polarizer of claim 1 wherein said retarders are selected from the group consisting of form-birefringence devices, liquid crystal polymer films, stretched polymer retarder sheets and crystalline retarders.

Claim 103

Dependent Claim 98 words

A color polarizer comprising: a pleochroic color polarizer of a third additive primary color; and a first retarder stack comprising two or more retarders, said first retarder stack positioned in series with said polarizer, wherein the number, N, of said retarders and the retardances and orientations of said retarders are such that a first additive primary color spectrum as well as said third additive primary color spectrum are transmitted along a first polarization axis and the complementary first subtractive primary color spectrum as well as said third additive primary spectrum are transmitted along a second, orthogonal, polarization axis.

Claim 104

Dependent Claim 98 words

A color polarizer comprising: a pleochroic color polarizer of a third additive primary color; and a first retarder stack comprising two or more retarders, said first retarder stack positioned in series with said polarizer, wherein the number, N, of said retarders and the retardances and orientations of said retarders are such that a first additive primary color spectrum as well as said third additive primary color spectrum are transmitted along a first polarization axis and the complementary first subtractive primary color spectrum as well as said third additive primary spectrum are transmitted along a second, orthogonal, polarization axis.

Claim 105

Dependent Claim 83 words

A color polarizer made by the process comprising the steps of: specifying a desired transmission spectrum profile for said color polarizer, said spectrum having an additive primary color along a first polarization axis and the complementary subtractive primary color along a second, orthogonal, axis; approximating said profile by a Fourier series; apodizing said series; using network synthesis to determine a retarder stack which provides the apodized series; and assembling said color polarizer by combining in series a linear polarizer and said retarder stack.

Claim 106

Dependent Claim 83 words

A color polarizer made by the process comprising the steps of: specifying a desired transmission spectrum profile for said color polarizer, said spectrum having an additive primary color along a first polarization axis and the complementary subtractive primary color along a second, orthogonal, axis; approximating said profile by a Fourier series; apodizing said series; using network synthesis to determine a retarder stack which provides the apodized series; and assembling said color polarizer by combining in series a linear polarizer and said retarder stack.

Claim 107

Dependent Claim 14 words

The color polarizer of claim 103 wherein said desired profile is a square wave.

Claim 108

Dependent Claim 21 words

The color polarizer of claim 103 wherein said step of apodizing comprises multiplying said Fourier series by a tapered window function.

Claim 109

Independent Claim 132 words

A method of providing light switchable between three primary colors, comprising the steps of: providing a color filter comprising; first, second and third linear polarizers positioned in series; first and second retarder stacks, each comprising two or more retarders, said first and second retarder stacks positioned between said first and second polarizers and between said second and third polarizers, respectively; and first and second polarization switches, positioned between said first retarder stack and said second polarizer and between said second retarder stack and said second polarizer, respectively; impinging white light on said color filter; and switching said first and said second polarization switches; wherein the number of retarders in said first and second retarder stacks, and the retardances and orientations thereof are such that said color filter switches between three primary colors.

Claim 110

Independent Claim 132 words

A method of providing light switchable between three primary colors, comprising the steps of: providing a color filter comprising; first, second and third linear polarizers positioned in series; first and second retarder stacks, each comprising two or more retarders, said first and second retarder stacks positioned between said first and second polarizers and between said second and third polarizers, respectively; and first and second polarization switches, positioned between said first retarder stack and said second polarizer and between said second retarder stack and said second polarizer, respectively; impinging white light on said color filter; and switching said first and said second polarization switches; wherein the number of retarders in said first and second retarder stacks, and the retardances and orientations thereof are such that said color filter switches between three primary colors.

Claim 111

Dependent Claim 15 words

The method of claim 106 wherein said three primary colors are red, green and blue.

Claim 112

Dependent Claim 43 words

The method of claim 107 wherein said first retarder stack comprises five retarders, each having retardance Γ where Γ is a fixed retardance, and wherein the orientations of the first through fifth retarders are about 45, -15, -15, 10 and 10 degrees, respectively.

Claim 113

Dependent Claim 44 words

The method of claim 108 wherein said second retarder stack comprises six retarders, each having retardance Γ' where Γ' is a fixed retardance, and wherein the orientations of the first through sixth retarders are about 8.3, 18, 18, -3.7, -45 and -78 degrees, respectively.

Claim 114

Dependent Claim 23 words

The method of claim 109 wherein Γ is a full-wave at about 600 nm and Γ' is a full-wave at about 643 nm.

Claim 115

Dependent Claim 114 words

A digital camera comprising: a color filter comprising: first, second and third linear polarizers positioned in series; first and second retarder stacks, each comprising two or more retarders, said first and second retarder stacks positioned between said first and second polarizers and between said second and third polarizers, respectively; and first and second polarization switches, positioned between said first retarder stack and said second polarizer and between said second retarder stack and said second polarizer, respectively; wherein the number of retarders in said first and second retarder stacks, and the retardances and orientations thereof are such that said color filter switches between three primary colors; and a receiver in series with said color filter.

Claim 116

Dependent Claim 114 words

A digital camera comprising: a color filter comprising: first, second and third linear polarizers positioned in series; first and second retarder stacks, each comprising two or more retarders, said first and second retarder stacks positioned between said first and second polarizers and between said second and third polarizers, respectively; and first and second polarization switches, positioned between said first retarder stack and said second polarizer and between said second retarder stack and said second polarizer, respectively; wherein the number of retarders in said first and second retarder stacks, and the retardances and orientations thereof are such that said color filter switches between three primary colors; and a receiver in series with said color filter.

Claim 117

Dependent Claim 16 words

The digital camera of claim 111 wherein said three primary colors are red, green and blue.

Claim 118

Dependent Claim 44 words

The digital camera of claim 112 wherein said first retarder stack comprises five retarders, each having retardance Γ where Γ is a fixed retardance, and wherein the orientations of the first through fifth retarders are about 45, -15, -15, 10 and 10 degrees, respectively.

Claim 119

Dependent Claim 45 words

The digital camera of claim 113 wherein said second retarder stack comprises six retarders, each having retardance Γ' where Γ' is a fixed retardance, and wherein the orientations of the first through sixth retarders are about 8.3, 18, 18, -3.7, -45 and -78 degrees, respectively.

Claim 120

Dependent Claim 24 words

The digital camera of claim 114 wherein Γ is a full-wave at about 600 nm and Γ' is a full-wave at about 643 nm.

Claim 121

Dependent Claim 14 words

The digital camera of claim 111 wherein said receiver is a multiple element detector.

Claim 122

Dependent Claim 24 words

The digital camera of claim 116 wherein said color filter is divided into two or more segments, each of said segments being independently switchable.

Claim 123

Dependent Claim 22 words

The digital camera of claim 116 further comprising imaging optics positioned on the same side of said receiver as said color filter.

Claim 124

Dependent Claim 21 words

The digital camera of claim 111 wherein said first and said second polarization switches each comprise a smectic liquid crystal cell.

Claim 125

Dependent Claim 41 words

The digital camera of claim 119 wherein said first and second polarization switches each comprise an achromatic compound half-wave retarder, said achromatic retarder having composite orientation switchable between a first orientation of 0 or π/2 and a second orientation of ±π/4.

Claim 126

Dependent Claim 21 words

The digital camera of claim 111 wherein said first and said second polarization switches each comprise a nematic liquid crystal cell.

Claim 127

Dependent Claim 162 words

A field sequential electronic camera comprising: an electronic receiver array; an optical imaging system that is optically coupled to the electronic receiver array; a color filter system that is optically coupled to the electronic receiver array, the color filter system controlling the transmission of a plurality of colors that are received by the electronic receiver array in sequence, and including: first and second retarder stacks, each comprising a plurality of retarders, wherein the first retarder stack transmits a first additive primary color along a first polarization axis and transmits a complementary color of the additive primary color along a second polarization axis; and a polarization switch positioned between the first retarder stack and the second retarder stack, the number of retarders in the first retarder stack, and the retardances and orientations thereof, are such that the color filter switches between a first color and a second color that are recorded by the electronic receiver array in sequence to form a color image.

Claim 128

Dependent Claim 162 words

A field sequential electronic camera comprising: an electronic receiver array; an optical imaging system that is optically coupled to the electronic receiver array; a color filter system that is optically coupled to the electronic receiver array, the color filter system controlling the transmission of a plurality of colors that are received by the electronic receiver array in sequence, and including: first and second retarder stacks, each comprising a plurality of retarders, wherein the first retarder stack transmits a first additive primary color along a first polarization axis and transmits a complementary color of the additive primary color along a second polarization axis; and a polarization switch positioned between the first retarder stack and the second retarder stack, the number of retarders in the first retarder stack, and the retardances and orientations thereof, are such that the color filter switches between a first color and a second color that are recorded by the electronic receiver array in sequence to form a color image.

Claim 129

Dependent Claim 12 words

The camera of claim 122 wherein the camera comprises a video camera.

Claim 130

Dependent Claim 21 words

The camera of claim 122 wherein the color filter is positioned between the optical imaging system and the electronic receiver array.

Claim 131

Dependent Claim 21 words

The camera of claim 122 wherein the optical imaging system is positioned between the color filter and the electronic receiver array.

Claim 132

Dependent Claim 14 words

The camera of claim 122 wherein the color filter switches between three primary colors.

Claim 133

Dependent Claim 15 words

The camera of claim 126 wherein the three primary colors comprise red, green and blue.

Claim 134

Dependent Claim 13 words

The camera of claim 122 wherein each retarder comprises a stretched polymer film.

Claim 135

Dependent Claim 12 words

The camera of claim 122 wherein the electronic receiver array is pixelated.

Claim 136

Dependent Claim 15 words

The camera of claim 122 wherein the polarization switch comprises a pixelated liquid crystal device.

Claim 137

Independent Claim 83 words

A method of making a color polarizer, comprising the steps of: specifying a desired transmission spectrum profile for said color polarizer, said spectrum having an additive primary color along a first polarization axis and the complementary subtractive primary color along a second, orthogonal, axis; approximating said profile by a Fourier series; apodizing said series; using network synthesis to determine a retarder stack which provides the apodized series; and assembling said color polarizer by combining in series a linear polarizer and said retarder stack.

Claim 138

Independent Claim 83 words

A method of making a color polarizer, comprising the steps of: specifying a desired transmission spectrum profile for said color polarizer, said spectrum having an additive primary color along a first polarization axis and the complementary subtractive primary color along a second, orthogonal, axis; approximating said profile by a Fourier series; apodizing said series; using network synthesis to determine a retarder stack which provides the apodized series; and assembling said color polarizer by combining in series a linear polarizer and said retarder stack.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2001-05-11	2001-11-10	2002-05-12	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2005-05-11	2005-11-10	2006-05-12	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2009-05-11	2009-11-10	2010-05-12	$7700.00	Window Closed / Lapsed

Color polarizers for polarizing an additive color spectrum along a first axis and it's compliment along a second axis

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag