EP0343903A2
Expired / Lapsed
EP
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Liquid crystal devices
Assignee: Imperial Chemical Industries Ltd
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Filing: 1989-05-22
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Granted: —
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Expires: 2009-05-22
Abstract
Abstract A liquid crystal device comprises a layer of fibres or filaments (15) permeated with liquid crystal material, the layer (15) being located between electrodes (13, 14) by means of which an electric field can be applied across the layer to vary the transmissivity of the liquid crystal/fibre composite. The diameters of the fibres/filaments are selected so that the light transmissivity of the composite has reduced sensitivity with respect to mismatch of the refractive indices of the liquid crystal and the fibres/filaments.
Inventors
- 👤 Colin Martin Waters
- 👤 Timothy James Noakes
- 👤 Ian Pavey
- 👤 Chiyoji Hitomi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 01:53
CPC Classifications
C; C09; C09K; C09K19/00; C09K19/52; C09K19/54; C09K19/542; C09K19/544; G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1334; G02F1/1339; G02F1/13345; G02F1/13392
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
78 words
A liquid crystal device comprising containment means enclosing liquid crystal material, means for applying an electric or magnetic field across the liquid crystal material and a permeable body of optically non-absorbing material permeated by the liquid crystal material such that light transmission through the composite comprising said body and the liquid crystal material is reduced in the off state of said field-applying means, characterised in that said permeable body comprises fibres or filaments deposited to form a layer.
Claim 2
Dependent Claim
78 words
A liquid crystal device comprising containment means enclosing liquid crystal material, means for applying an electric or magnetic field across the liquid crystal material and a permeable body of optically non-absorbing material permeated by the liquid crystal material such that light transmission through the composite comprising said body and the liquid crystal material is reduced in the off state of said field-applying means, characterised in that said permeable body comprises fibres or filaments deposited to form a layer.
Claim 3
Dependent Claim
56 words
A device as claimed in Claim 1 in which said fibres or filaments have diameters such that, in the field-off state, domain formation is promoted in the liquid crystal material on a scale such that at least 25% of the light attenuation in the off-state is attributable to light scattering as a result of domain formation.
Claim 4
Dependent Claim
113 words
A liquid crystal device comprising containment means enclosing liquid crystal material, means for applying an electric or magnetic field across the liquid crystal material, and a permeable body of optically absorbing material permeated by the liquid crystal such that light transmission through the composite comprising said body and the liquid crystal material is reduced in the off state of said field-applying means, characterised in that said permeable body comprises fibres or filaments having diameters such that, in the field-on liquid crystal-aligned state of the device, the light transmissivity of said composite is substantially insensitive to differences of up to 0.01 in the ordinary refractive indices of the liquid crystal material and said fibres/filaments.
Claim 5
Dependent Claim
113 words
A liquid crystal device comprising containment means enclosing liquid crystal material, means for applying an electric or magnetic field across the liquid crystal material, and a permeable body of optically absorbing material permeated by the liquid crystal such that light transmission through the composite comprising said body and the liquid crystal material is reduced in the off state of said field-applying means, characterised in that said permeable body comprises fibres or filaments having diameters such that, in the field-on liquid crystal-aligned state of the device, the light transmissivity of said composite is substantially insensitive to differences of up to 0.01 in the ordinary refractive indices of the liquid crystal material and said fibres/filaments.
Claim 6
Dependent Claim
43 words
A device as claimed in Claim 3 in which said fibre/filament diameters are such that, in the field-on, aligned state the light transmissivity of said composite varies by no more than 10% in response to ordinary refractive index differences ranging up to 0.01.
Claim 7
Dependent Claim
43 words
A device as claimed in Claim 3 in which said fibre/filament diameters are such that, in the field-on, aligned state the light transmissivity of said composite varies by no more than 5% in response to ordinary refractive index differences ranging up to 0.01.
Claim 8
Independent Claim
27 words
A device as claimed in any one of Claims 3 to 5 in which said insensitivity is exhibited for ordinary refractive index differences ranging up to 0.02.
Claim 9
Independent Claim
42 words
A device as claimed in any one of Claims 1-6 in which the ordinary refractive indices of the liquid crystal material and said fibres/filaments differ and the light transmissivity of said composite is at least 90% in the field-on liquid crystal-aligned state.
Claim 10
Dependent Claim
17 words
A device as claimed in Claim 7 in which said refractive indices differ by at least 0.005.
Claim 11
Dependent Claim
17 words
A device as claimed in Claim 7 in which said refractive indices differ by up to 0.01.
Claim 12
Dependent Claim
17 words
A device as claimed in claim 7 in which said refractive indices differ by up to 0.012.
Claim 13
Independent Claim
23 words
A device as claimed in any one of Claims 1-10 in which at least a major proportion of said fibres/filaments have sub-micronic diameters.
Claim 14
Independent Claim
23 words
A device as claimed in any any one of claims 1-10 in which 50% of said fibres/filaments have diameters no greater than 500nm.
Claim 15
Independent Claim
24 words
A device as claimed in any one of Claims 1-10 in which at least 70% of said fibres/filaments have diameters no greater than 500nm.
Claim 16
Independent Claim
22 words
A device as claimed in any one of Claims 1-13 in which the fibres/filaments have an average diameter less than 1 micron.
Claim 17
Independent Claim
22 words
A device as claimed in any one of Claims 1-13 in which the fibres/filaments have an average diameter less than 750 nm.
Claim 18
Independent Claim
22 words
A device as claimed in any one of Claims 1-13 in which the fibres/filaments have an average diameter less than 500 nm.
Claim 19
Independent Claim
25 words
A device as claimed in any one of Claims 1 to 16 in which said permeable body comprises a mat of said fibres or filaments.
Claim 20
Dependent Claim
16 words
A device as claimed in in Claim 17 in which said mat is produced by spinning.
Claim 21
Independent Claim
25 words
A device as claimed in any one of Claims 1-18 in which, in the field-off state, the transmissivity of said composite is less than 30%.
Claim 22
Independent Claim
47 words
A device as claimed in any one of Claims 1-19 in which, in the field-off state, the transmissivity of said composite is reduced predominantly by light scattering by domains formed in the liquid crystal material as a consequence of the presence of sub-micronic fibres or filaments therein.
References Cited (Backward Citations)
No citation records indexed.
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