Patent EP0259058A2 successfully refreshed from Google Patents.
EP0259058A2
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EP
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Projection-type multi-colour liquid crystal display device
Assignee: Fujitsu Ltd
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Filing: 1987-08-19
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Granted: —
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Expires: 2007-08-19
Abstract
Abstract A bright and large information capacity projection-type multi-colour liquid crystal display can be realized by a display device comprising a liquid crystal panel (A,B) having a plurality of layers of cholesteric-nematic phase transition type liquid crystals (13, 14) having a positive dielectric anisotropy and phase transition hysterisis when a voltage is applied. The liquid crystals (13, 14) are driven to have some portions having homeotropic texture and other portions having forcalconic texture which are maintained when at a certain voltage is applied. When white light is transmitted through the liquid crystals (13, 14) a desired colour can be obtained by selecting the thickness of the liquid crystal layer and the refractive index anisotropy of the liquid crystal of the liquid crystal layers.
Inventors
- 👤 Yasuo Yamagishi
- 👤 Akihiro Mochizuki
- 👤 Masayuki Iwasaki
- 👤 Toshiaki Fujitsu Meiwa-Ryo 115 Yoshihara
- 👤 Fumiyo Onda
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 22:46
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/133526; G02F1/1347; G02F1/137; G02F1/13731; G03; G03B; G03B21/00; G03B21/132
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
258 words
A projection-type liquid crystal multi-colour display device; comprising: a liquid crystal panel (A,B) having a plurality of layers of cholesteric-nematic phase transition type liquid crystals (13, 14) having a positive dielectric anisotropy and a refractive index anisotropy, each of the layers (13, 14) having a layer thickness, the liquid crystals being in, depending on an applied electrical voltage history, either a homeotropic or forcalconic texture when a certain electrical voltage is applied to the liquid crystal layer, the liquid crystal layers being able to form an image comprised of homeotropic and forcalconic textures by selectively applying different electrical voltage histories and then maintaining said certain electrical voltage at the liquid crystal layer, wherein the refractive index anisotropy of the liquid crystal and the layer thickness of each of the liquid crystal layers are selected so that light transmitted through each liquid crystal layer (13, 14) is coloured differently if it is incident normal to a portion of each liquid crystal layer having a forcalconic texture, than if it is incident on a portion of the liquid crystal layers (13, 14) having a homeotropic texture which is transparent; and, an optical system (1,2,4,5) for making a light incident substantially normally to the liquid crystal panel (A,B) and for forming a projected image of the image of the homeotropic and forcalconic textures in the liquid crystal panel (A,B) on a screen (7), whereby light which has been transmitted through forcalconic textured portions of the liquid crystal layers (13, 14) is coloured, so that the projected image is a multi-colour image.
Claim 2
Dependent Claim
258 words
A projection-type liquid crystal multi-colour display device; comprising: a liquid crystal panel (A,B) having a plurality of layers of cholesteric-nematic phase transition type liquid crystals (13, 14) having a positive dielectric anisotropy and a refractive index anisotropy, each of the layers (13, 14) having a layer thickness, the liquid crystals being in, depending on an applied electrical voltage history, either a homeotropic or forcalconic texture when a certain electrical voltage is applied to the liquid crystal layer, the liquid crystal layers being able to form an image comprised of homeotropic and forcalconic textures by selectively applying different electrical voltage histories and then maintaining said certain electrical voltage at the liquid crystal layer, wherein the refractive index anisotropy of the liquid crystal and the layer thickness of each of the liquid crystal layers are selected so that light transmitted through each liquid crystal layer (13, 14) is coloured differently if it is incident normal to a portion of each liquid crystal layer having a forcalconic texture, than if it is incident on a portion of the liquid crystal layers (13, 14) having a homeotropic texture which is transparent; and, an optical system (1,2,4,5) for making a light incident substantially normally to the liquid crystal panel (A,B) and for forming a projected image of the image of the homeotropic and forcalconic textures in the liquid crystal panel (A,B) on a screen (7), whereby light which has been transmitted through forcalconic textured portions of the liquid crystal layers (13, 14) is coloured, so that the projected image is a multi-colour image.
Claim 3
Dependent Claim
92 words
A device according to claim 1, wherein the optical system comprises a light source (1), a first convex Fresnel lens (2) for converting a light from the light source to a substantially parallel light beam incident normal to the liquid crystal panel (A,B) a second convex Fresnel lens (4) for condensing the parallel light transmitted through the liquid crystal panel (A,B) and an image-forming lens (5) for receiving the condensed light from the second Fresnel lens (4) and for forming an image from the light transmitted through the liquid crystal panel (A,B).
Claim 4
Dependent Claim
112 words
A device according to claim 1, wherein the optical system comprises a light source (1) a first convex Fresnel lens (23) for providing a convergent beam of light, a concave Fresnel lens (21) for converting the convergent light beam to a parallel light beam incident substantially normally to the liquid crystal panel (A,B), a second convex Fresnel lens (22) for condensing the parallel light transmitted through the liquid crystal panel (A,B), and a projecting lens (26), the device having the form of an overhead projector which is designed to make a convergent light transmit an image of an original placed on the overhead projector to form a projected image on a screen.
Claim 5
Dependent Claim
95 words
A liquid crystal panel device (A,B) comprising a plurality of layers of cholesteric-nematic phase transition type liquid crystals (13, 14) having a positive dielectric, anisotropy and a refractive index anisotropy, the layers of liquid crystals (13, 14) each including electrodes (12) to enable the liquid crystals to be oriented with their axes parallel to the layers in their forcalconic state, the plurality of layers of liquid crystals (13, 14) having different thicknesses and/or different refractive index anisotropy from one another so that, in their forcalconic state each layer selectively transmits light of a different colour.
Claim 6
Dependent Claim
95 words
A liquid crystal panel device (A,B) comprising a plurality of layers of cholesteric-nematic phase transition type liquid crystals (13, 14) having a positive dielectric, anisotropy and a refractive index anisotropy, the layers of liquid crystals (13, 14) each including electrodes (12) to enable the liquid crystals to be oriented with their axes parallel to the layers in their forcalconic state, the plurality of layers of liquid crystals (13, 14) having different thicknesses and/or different refractive index anisotropy from one another so that, in their forcalconic state each layer selectively transmits light of a different colour.
Claim 7
Dependent Claim
65 words
A device according to claim 4, in which the liquid crystal panel (A,B) is sandwiched between a concave Fresnel lens (21) and a convex Fresnel lens (22) of similar focal length, the concave lens (21) converting a convergent light beam from a conventional overhead projector into a beam substantially normal to the liquid crystal panel (A,B) and the convex lens then reforming a convergent beam.
Claim 8
Independent Claim
31 words
A device according to any one of the preceding claims, wherein the liquid crystal layers (13, 14) include a mixture of a nematic liquid crystal and a chiral nematic liquid crystal.
Claim 9
Independent Claim
25 words
A device according to any one of the preceding claims, wherein the thickness of the liquid crystal in each layer is 15 µm or less.
Claim 10
Independent Claim
25 words
A device according to any one of the preceding claims, wherein the thickness of the liquid crystal in each layer is 10 µm or less.
Claim 11
Independent Claim
25 words
A device according to any one of the preceding claims, wherein the cholesteric liquid crystal has a spiral pitch of between 0.5 and 2 µm.
References Cited (Backward Citations)
No citation records indexed.
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