US4741859A
Expired / Lapsed
US
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Thermochromic liquid crystal materials and devices
Assignee: Qinetiq Ltd
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Filing: 1986-06-18
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Granted: 1988-05-03
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Expires: 2006-06-18
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 their thermochromic 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 G. McDonnell
- 👤 Jennifer Constant
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 05:24
CPC Classifications
C; C09; C09K; C09K19/00; C09K19/04; C09K19/42; C09K19/46; C09K19/02; C09K19/44
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
94 words
A liquid crystal material showing thermochromic behavior in a cholesteric mesophase 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, said material containing one or more of each of the compound types having general formulae: ##STR50## where R is selected from n-alkyl and n-alkoxy containing up to 12 carbon atoms and R 1 and R 2 are independently selected from n-alkyl containing up to 12 carbon atoms and Rc represents optically active 2-methylbutyl.
Claim 2
Dependent Claim
94 words
A liquid crystal material showing thermochromic behavior in a cholesteric mesophase 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, said material containing one or more of each of the compound types having general formulae: ##STR50## where R is selected from n-alkyl and n-alkoxy containing up to 12 carbon atoms and R 1 and R 2 are independently selected from n-alkyl containing up to 12 carbon atoms and Rc represents optically active 2-methylbutyl.
Claim 3
Dependent Claim
79 words
A liquid crystal material showing thermochromic behavior in a cholesteric mesophase 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, said material containing one or more of each of the compound types having general formulae: ##STR51## 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 4
Dependent Claim
79 words
A liquid crystal material showing thermochromic behavior in a cholesteric mesophase 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, said material containing one or more of each of the compound types having general formulae: ##STR51## 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
79 words
A liquid crystal material showing thermochromic behavior in a cholesteric mesophase 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, said material containing one or more of each of the compound types having general formulae: ##STR52## 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
79 words
A liquid crystal material showing thermochromic behavior in a cholesteric mesophase 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, said material containing one or more of each of the compound types having general formulae: ##STR52## 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 7
Dependent Claim
81 words
A liquid crystal material showing thermochromic behavior in a cholesteric mesophase over the visible region comprising a mixture of two or more components, characterised in that the mixture shows an injected smetic phase at a lower temperature than its cholesteric mesophase, said material containing one or more of each of the compound types having general formulae: ##STR53## 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
81 words
A liquid crystal material showing thermochromic behavior in a cholesteric mesophase over the visible region comprising a mixture of two or more components, characterised in that the mixture shows an injected smetic phase at a lower temperature than its cholesteric mesophase, said material containing one or more of each of the compound types having general formulae: ##STR53## 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
37 words
A thermochromic liquid crystal mixture according to claim 1, 2, 3 or 4, characterised in that the groups R, R 1 , R 2 , R', R" and R A contain 7 to 10 carbon atoms each.
Claim 10
Dependent Claim
47 words
A liquid crystal material according to claim 1 wherein the compounds in the mixture include those where R is C 8 H 17 , C 10 H 21 and C 10 H 21 O, and R 1 and R 2 are both C 7 H 15 .
Claim 11
Dependent Claim
23 words
A thermochromic ink characterised in that it contains microencapsulated droplets of a liquid crystal composition according to claim 1, 2, 3 or 4.
Claim 12
Dependent Claim
21 words
A temperature indicating device, characterised in that it includes a liquid crystal mixture according to claim 1, 2, 3 or 4.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-05-03 | 1991-11-02 | 1992-05-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-03 | 1995-11-02 | 1996-05-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-03 | 1999-11-02 | 2000-05-03 | $7700.00 | Window Closed / Lapsed |