# US 5,345,322 A · Complementary color liquid crystal display

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- Number: US 5,345,322 A
- Document ID: US5345322A
- Status: Granted
- Kind: A
- Application number: 08/057,182
- Filed: 1993-05-03
- Granted: 1994-09-06
- Earliest claimed: 1985-03-01
- Assignees: Manchester R & D Partnership
- Inventors: James L. Fergason
- Web page: https://patentgrep.com/patent/US5345322A

## CPC

- G02F 1/13725: {based on guest-host interaction (G02F1/13762, G02F1/13737, take precedence)}
- C09K 19/544: {as dispersing or encapsulating medium around the liquid crystal}
- C09K 19/60: Pleochroic dyes
- G02F 1/1334: based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
- G02F 1/1347: Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
- G02F 1/13475: {in which at least one liquid crystal cell or layer is doped with a pleochroic dye, e.g. GH-LC cell (G02F1/13476 takes precedence)}
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE

## Abstract

A liquid crystal color device (10) includes at least one pel (14) for affecting light (36) incident thereon to produce output light (38), the pel includes three complementary color subsets (30, 32, 34), each having controllable color filtering capability in the respective complementary colors thereof. The color subsets are arranged in optical additive relation, and the color subsets include complementary color parts (30a, 30b, 32a, 32b, 34a, 34b) which are arranged, respectively, in optical serial/subtractive relation. The color filtering function is carried out using liquid crystal materials with respective pleochroic dyes. A method of parametric color control of a liquid crystal device, formed of plural picture elements, each picture element including plural pairs of complementary color filters, comprising directing light to or through an array of such electrically controllable pairs of complementary color filters, and controlling the filtering characteristics of at least one of such filters.

## Claims

### Claim 1

A liquid crystal color device, comprising at least one pel means for affecting light incident thereon to produce output light,
said at least one pel means including at least two color subsets, one subset including a first color and the complement thereof, and the other including a second color and the complement thereof, with said subsets being arranged in optical additive relation, and
wherein each of said subsets comprises one or more volumes of liquid crystal material in a containment medium, and said containment medium comprises surface means for effecting a structural alignment of said liquid crystal material due to surface interaction with said surface means to obtain selectively substantial filtering or non-filtering of said incident light as a function of a prescribed input.

### Claim 2 (depends on 1)

The device of claim 1, each of said subsets comprising one or more volumes of liquid crystal material containing pleochroic dye of one of said colors and one or more volumes of liquid crystal material containing pleochroic dye of the complementary color of said respective one of said colors.

### Claim 3 (depends on 2)

The device of claim 2, wherein said volumes of liquid crystal containing pleochroic dye are formed in a medium that provides curved surface means for affecting alignment of said liquid crystal material by interaction with said curved surface means to obtain selective filtering or non-filtering of incident light as a function of the applying or not of the input or a characteristic of the input.

### Claim 4 (depends on 3)

The device of claim 3, wherein said liquid crystal material has low or zero birefringence, and the index of refraction of said liquid crystal material is substantially the same as the index of refraction of said medium.

### Claim 5 (depends on 2)

The device of claim 2, wherein said respective first and second mentioned one or more volumes are arranged in separate layers without any support structure therebetween.

### Claim 6 (depends on 2)

The device of claim 2, wherein in at least one of said subsets each of said respective first and second mentioned one or more volumes comprises a plurality of volumes of liquid crystal material in a medium, and wherein both of said pluralities of volumes of said at least one of said subsets are arranged-in a common substantially homogeneous layer.

### Claim 7 (depends on 2)

The device of claim 2, wherein said input is an electric field and said plurality of volumes of liquid crystal material are operable to discriminate a field input to determine optical filtering function thereof in response to such field input.

### Claim 8 (depends on 74)

The device of claim 74, wherein said plurality of volumes of liquid crystal material are operable to discriminate as a function of at least one of volume size and response of the liquid crystal in a volume to voltage and/or frequency.

### Claim 9 (depends on 2)

The device of claim 2, each of said volumes of liquid crystal material and pleochroic dye comprising operationally nematic or operationally smectic liquid crystal, said surface means being cooperative with said liquid crystal material to distort the natural structure of the liquid crystal to cause coloring or color filtering of incident light by pleochroic dye therein, and said liquid crystal and pleochroic dye reducing the amount of such coloring or color filtering in response to a field input.

### Claim 10

A liquid crystal color device, comprising
at least one pel means for affecting light incident thereon by transmitting and/or filtering such light to produce output light,
said at least one pel means including at least two color subsets,
one subset including a first color and the complementary color of that color, and the other including a second color and the complementary color of that color,
said subsets being responsive to an input to alter light transmitting or absorbing properties thereof,
the color and complementary color of each subset being arranged in optically subtractive relation,
said subsets being arranged in optical additive relation such that the optical outputs from different subsets within a pel means combine additively, and
said one subset being optically cooperative with said other subset selectively to contribute the color of said second color of light in the output light of said pel means.

### Claim 11 (depends on 10)

The device of claim 10, wherein the complementary color of said one subset includes as one color component thereof the color of said other subset, said one subset being responsive to an input to transmit said one color component to cooperate with said other subset to brighten the second color of said other subset in the output light of said pel means.

### Claim 12 (depends on 10)

The device of claim 10, comprising a plurality of said pel means arranged in optical additive relation.

### Claim 13 (depends on 12)

The device of claim 12, wherein respective subsets of a pel means are arranged in optically additive relation, and plurality of pel means are positioned in an optical display in cooperative relation to provide independent control of color and brightness of output light produced from input incident light, said subsets and pel means being selectively and independently operative to control saturation and hue.

### Claim 14 (depends on 10)

The device of claim 10, said pel means further comprising at least a third color subset, said third-color subset including a third color and the complementary color thereof.

### Claim 15 (depends on 14)

The device of claim 14, wherein all subsets of a pel means are optically cooperative with all the other subsets of said pel means to contribute to the output light at least one color of light produced by the other respective subsets.

### Claim 16 (depends on 14)

The device of claim 14, wherein said colors comprise three primary colors.

### Claim 17 (depends on 16)

The device of claim 16, said colors of respective subsets comprising a red, green and blue triad.

### Claim 18 (depends on 17)

The device of claim 17, wherein for the subset having red color the complementary color is cyan which includes blue and green color components, for the subset having green color the complementary color is magenta which includes blue and yellow components, and for the subset having blue color the complementary color is yellow which includes red and green components.

### Claim 19 (depends on 10)

The device of claim 10, further comprising light source means for providing incident multicolor light for impingement on said pel means.

### Claim 20 (depends on 10)

The device of claim 10, further comprising reflector means for reflecting light transmitted through respective subsets back through said respective subsets.

### Claim 21 (depends on 10)

The device of claim 10, further comprising driving means for selectively applying electrical field to said pel means as the input to determine the effect each of said pel means has on incident light thereby to determine characteristics of output light.

### Claim 22 (depends on 10)

The device of claim 10, said pel means comprising a plurality of pel means arranged in generally two dimensional relation to form a multicolor display.

### Claim 23 (depends on 10)

The device of claim 10, said pel means being arranged in a substantially flat display.

### Claim 24 (depends on 10)

The device of claim 10, wherein said color and complementary color of respective subsets form complementary color pairs that are operative to provide substantially full gray scale.

### Claim 25 (depends on 10)

A color television comprising the device of claim 10.

### Claim 26

A method of displaying a multicolor output, comprising
selectively filtering one portion of multicolor incident light by a first controllable filter of a first color and the complementary color thereof,
selectively filtering another portion of multicolor incident light by a second controllable filter of a second color and the complementary color thereof,
wherein the complementary color of the first color includes at least one color component that is the same color as the second color, and
selectively using said at least one color component from the complementary color of the first color to contribute said same color to the output.

### Claim 27 (depends on 26)

The method of claim 26, further characterized in that said step of selectively using said at least one color component comprises using said at least one color component independently of whether said second color is provided the output by said selectively filtering another portion step.

### Claim 28 (depends on 26)

The method of claim 26, further characterized in comprising selectively filtering a third portion of multicolor incident light by a third controllable filter of a third color and the complementary color thereof, wherein the complementary color of the third color includes at least one color component that is the same color as the second color, and selectively using said last specified color component to contribute said same color to the output.

### Claim 29 (depends on 26)

The method of claim 26, further characterized in that the complementary color of the color of each respective controllable filter includes color components that are the same as the colors of at least two other controllable filters, and said selectively using step includes using respective color components of said complementary colors to contribute to the output respective colors that are the same as one or more controllable filters.

### Claim 30 (depends on 26)

The method of claim 26, further characterized in selecting the colors of respective controllable filters as primary colors.

### Claim 31 (depends on 26)

The method of claim 26, further characterized in selecting the colors of respective controllable filters as red, green and blue and the respective complementary colors thereof as cyan, magenta and yellow.

### Claim 32 (depends on 26)

The method of claim 26, further characterized in controlling intensity of a color of a controllable filter by controlling the extent of light filtering by the respective complementary color of said color.

### Claim 33 (depends on 26)

The method of claim 26, further characterized in controlling saturation of a color of a controllable filter by controlling the filtering properties of the color of such controllable filter.

### Claim 34 (depends on 26)

The method of claim 26, further characterized in adding to the brightness of a color of a controllable filter by contributing said at least one color component of at least one complementary color of another controllable color filter.

### Claim 35 (depends on 26)

The method of claim 26, further characterized in placing color and complementary color portions of respective controllable filters in optical series in close proximity to minimize parallax and placing plural controllable filters in close proximity in optical additive relation.

### Claim 36 (depends on 26)

The method of claim 26, further characterized in using red, green and blue controllable filters as a pel (picture element), and using plural pels in relation to form a multicolor display.

### Claim 37 (depends on 26)

The method of claim 26, further characterized in that said controllable filters include liquid crystal material and pleochroic dye, and said selective filtering comprises controlling the alignment properties of the liquid crystal and pleochroic dye to present different color filtering characteristics to light.

### Claim 38 (depends on 26)

The method of claim 26, further characterized in controlling said selective filtering steps to produce a variety of color and brightness output responses.

### Claim 39 (depends on 38)

The method of claim 38, further characterized in providing incident light to the controllable filters and supplying an input to plural controllable filters to minimize filtering thereby to produce a bright output light that is the color of such incident light.

### Claim 40 (depends on 26)

The method of claim 26, further characterized in using at least one controllable filter to produce color output and at least part of another controllable filter to enhance the brightness of such color output.

### Claim 41 (depends on 26)

The method of claim 26, further characterized in using plural controllable filters to produce substantially full gray scale.