EP0206680A2
Expired / Lapsed
EP
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Thermochomic liquid crystal materials and devices
Assignee: Qinetiq Ltd
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Filing: 1986-06-13
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Granted: —
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Expires: 2006-06-13
Abstract
Abstract A novel method of preparing thermochromic liquid crystal mixtures is provided in which mixtures which show an injected smectic phase at lower temperatures than theirthermochromic cholesteric phase are prepared, and by following the envelope of the injected smectic - cholesteric transition on the phase diagram a series of thermochromic compositions containing the same components but having a series of working temperature ranges are obtained.Novel thermochromic liquid crystal mixtures prepared using the method are also provided.
Inventors
- 👤 Damien Gerard Mcdonnell
- 👤 Jennifer Constant
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 23:28
CPC Classifications
C; C09; C09K; C09K19/00; C09K19/04; C09K19/42; C09K19/46; C09K19/02; C09K19/44
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
43 words
A liquid crystal material showing thermochromic behaviour in a cholesteric meso p hase over the visible region comprising a mixture of two or more components, characterised in that the mixture shows an injected smectic phase at a lower temperature than its cholesteric mesophase.
Claim 2
Dependent Claim
43 words
A liquid crystal material showing thermochromic behaviour in a cholesteric meso p hase over the visible region comprising a mixture of two or more components, characterised in that the mixture shows an injected smectic phase at a lower temperature than its cholesteric mesophase.
Claim 3
Dependent Claim
44 words
A thermochromic liquid crystal mixture as claimed in claim 1 containing one or more of each of the compound types having general formulae: where R and R' are independently selected from n-alkyl containing up to 12 carbon atoms and Rc represents optically active 2-methylbutyl.
Claim 4
Dependent Claim
45 words
A thermochromic liquid crystal mixture as claimed in claim 1 containing one or more of each of the compound types having general formulae: where R, R' and R" are independently selected from n-alkyl containing up to 12 carbon atoms and Rc represents optically active 2-methylbutyl.
Claim 5
Dependent Claim
45 words
A thermochromic liquid crystal mixture as claimed in claim 1 containing one or more of each of the compound types having general formulae: where R, R', and R" are independently selected from n-alkyl containing up to 12 carbon atoms and Rc represents optically active 2-methylbutyl.
Claim 6
Dependent Claim
23 words
A thermochromic liquid crystal mixture as claimed in claim 1 containing one or more of each of the compound types having general formulae:
Claim 7
Dependent Claim
25 words
(contd.) where R, R', R" and R A are independently selected from n-alkyl containing up to 12 carbon atoms and Rc represents optically active 2-methylbutyl.
Claim 8
Dependent Claim
25 words
(contd.) where R, R', R" and R A are independently selected from n-alkyl containing up to 12 carbon atoms and Rc represents optically active 2-methylbutyl.
Claim 9
Dependent Claim
33 words
A thermochromic liquid crystal mixture as claimed in any one of claims 2 to 5, characterised in that the n-alkyl groups R, R', R" and R A contain 7 to 10 carbon atoms.
Claim 10
Independent Claim
84 words
A method of preparing a thermochromic liquid crystal mixture that includes the steps of: (i) deciding a working temperature range, (ii) selecting components for the mixture which show an injected smectic phase over at least part of their temperature - composition phase diagram and a thermochromic cholesteric mesophase at higher temperatures. (iii) preparing a thermochromic mixture of such components such that the decided working temperature range of the mixture is in the vicinity of the injected smectic - cholesteric transition temperature of the mixture.
Claim 11
Independent Claim
84 words
A method of preparing a thermochromic liquid crystal mixture that includes the steps of: (i) deciding a working temperature range, (ii) selecting components for the mixture which show an injected smectic phase over at least part of their temperature - composition phase diagram and a thermochromic cholesteric mesophase at higher temperatures. (iii) preparing a thermochromic mixture of such components such that the decided working temperature range of the mixture is in the vicinity of the injected smectic - cholesteric transition temperature of the mixture.
Claim 12
Dependent Claim
19 words
A thermochromic liquid crystal composition characterised in that it is prepared by a method as claimed in claim 7.
Claim 13
Dependent Claim
27 words
A thermochromic ink characterised in that it contains micro-encapsulated droplets of a liquid crystal composition as claimed in any one of claims 2 to 6 or 8.
Claim 14
Dependent Claim
25 words
A temperature indicating device, characterised in that it includes a liquid crystal mixture as claimed in any one of claims 2 to 6 or 8.
References Cited (Backward Citations)
No citation records indexed.
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