US4257911A
Expired / Lapsed
US
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Liquid crystal materials
Assignee: UK Secretary of State for Defence
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Filing: 1979-07-27
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Granted: 1981-03-24
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Expires: 1999-07-27
Abstract
Abstract Liquid crystal materials are provided which are esters having the general formula: ##STR1## where n has the value 1, 2 or 3 and R is a normal or branched chain alkyl containing up to ten carbon atoms and preferably four to ten carbon atoms. These materials display a cholesteric mesophase and also a chiral smectic C mesophase underlying the cholesteric mesophase. Both of these mesophases are thermochromic.
Inventors
- 👤 George W. Gray
- 👤 Damien G. McDonnell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:30
CPC Classifications
C; C09; C09K; C09K19/00; C09K19/04; C09K19/06; C09K19/08; C09K19/10; C09K19/20; C09K19/2007; C09K19/2021; B; B01; B01D; B01D45/00; B01D45/12; B01D45/14; C07; C07C; C07C17/00; C07C17/093; C07C17/10; C07C17/12; C07C17/16; C07C17/35; C07C255/00; C07C43/00; C07C43/02; C07C43/20; C07C43/23; C07C49/00; C07C49/76; C07C49/80; C07C49/813; C07C51/00; C07C51/08; C07C51/15; C07C53/00; C07C53/126; C07C53/38; C07C53/42; C07C63/00; C07C63/33; C07C63/331; C07C63/68; C07C63/72; G; G01; G01K; G01K11/00; G01K11/12; G01K11/16; G01K11/165; C09K2019/2035
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
92 words
A liquid crystal material containing a plurality of compounds at least one of which is a cholesteric liquid crystal compound having a molecular helical pitch length of the order of 0.2 μm, wherein the improvement comprises the said cholesteric compound being an ester having the formula ##STR18## wherein R 1 is a branched alkyl group having a chiral center and R is an alkyl group having 1 to 10 carbon atoms with the proviso that the racemates of said at least one cholesteric ester compound are excluded from the liquid crystal material.
Claim 2
Dependent Claim
92 words
A liquid crystal material containing a plurality of compounds at least one of which is a cholesteric liquid crystal compound having a molecular helical pitch length of the order of 0.2 μm, wherein the improvement comprises the said cholesteric compound being an ester having the formula ##STR18## wherein R 1 is a branched alkyl group having a chiral center and R is an alkyl group having 1 to 10 carbon atoms with the proviso that the racemates of said at least one cholesteric ester compound are excluded from the liquid crystal material.
Claim 3
Dependent Claim
23 words
A liquid crystal material as claimed in claim 1 and wherein R is a straightchain alkyl group containing four to ten carbon atoms.
Claim 4
Dependent Claim
23 words
A liquid crystal material as claimed in claim 1 and wherein R 1 has a positive optical rotation angle and R is n-butyl.
Claim 5
Dependent Claim
23 words
A liquid crystal material as claimed in claim 1 and wherein R 1 has a positive optical rotation angle and R is n-pentyl.
Claim 6
Dependent Claim
23 words
A liquid crystal material as claimed in claim 1 and wherein R 1 has a positive optical rotation angle and R is n-hexyl.
Claim 7
Dependent Claim
23 words
A liquid crystal material as claimed in claim 1 and wherein R 1 has a positive optical rotation angle and R is n-heptyl.
Claim 8
Dependent Claim
23 words
A liquid crystal material as claimed in claim 1 and wherein R 1 has a positive optical rotation angle and R is n-octyl.
Claim 9
Dependent Claim
23 words
A liquid crystal material as claimed in claim 1 and wherein R 1 has a positive optical rotation angle and R is n-nonyl.
Claim 10
Dependent Claim
23 words
A liquid crystal material as claimed in claim 1 and wherein R 1 has a positive optical rotation angle and R is n-decyl.
Claim 11
Dependent Claim
28 words
A liquid crystal material as claimed in claim 1 and wherein R 1 is a 4-methylhexyl group which has a positive optical rotation angle and R is n-hexyl.
Claim 12
Dependent Claim
24 words
A liquid crystal electro-optic device of the phase change type in which the liquid crystal material is the liquid crystal material of claim 1.
Claim 13
Dependent Claim
101 words
A liquid crystal material as claimed in claim 1 and wherein the cholesteric ester compound is produced by the following route: (i) an optically active halide containing a group R' is converted into an optically active form of ##STR19## where R' is CH 3 CH 2 CH(CH 3 )(CH 2 ) n ; n=1, 2 or 3; (ii) ##STR20## is converted into an optically active form of ##STR21## (iii) ##STR22## is converted into an optically active form of ##STR23## (iv) ##STR24## is converted into an optically active form of ##STR25## (v) ##STR26## is converted into an optically active form of ##STR27##
Claim 14
Dependent Claim
14 words
A liquid crystal material as claimed in claim 12 and wherein R' is 2-methylbutyl.
Claim 15
Dependent Claim
103 words
A liquid crystal material as claimed in claim 1 and wherein the cholesteric ester compound is produced by the following route: (i) an optically active halide containing a group R" is converted into an optically active form of R"CO.Cl where R" is CH 3 CH 2 CH(CH 3 )(CH 2 ) m ; m=0, 1 or 2; (ii) R"COCl is converted into an optically active form of ##STR28## (iii) ##STR29## (iv) ##STR30## is converted into an optically active form of ##STR31## (v) ##STR32## is converted into an optically active form of ##STR33## (vi) ##STR34## is converted into an optically active form of ##STR35##
Claim 16
Dependent Claim
14 words
A liquid crystal material as claimed in claim 14 and wherein R" is 2-methylbutyl.
Claim 17
Dependent Claim
14 words
A liquid crystal material as claimed in claim 14 and wherein R" is 3-methylpentyl.
Claim 18
Dependent Claim
35 words
A liquid crystal material as claimed in claim 14 and wherein the conversion of ##STR36## involves producing as an intermediate product the acid chloride ##STR37## and reacting said acid chloride with a 4-alkoxy phenol ##STR38##
Claim 19
Dependent Claim
35 words
A liquid crystal material as claimed in claim 14 and wherein the conversion of ##STR39## involves producing as an intermediate product the acid chloride ##STR40## and reacting said acid chloride with a 4-alkoxy phenol ##STR41##
Claim 20
Dependent Claim
36 words
A liquid crystal material as claimed in claim 1 and wherein said material itself is cholesteric and has a molecular helical pitch length corresponding to a wavelength region in the visible spectrum for a given temperature.
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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) | 1984-03-23 | 1984-09-22 | 1985-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-23 | 1988-09-22 | 1989-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-23 | 1992-09-22 | 1993-03-24 | $7700.00 | Window Closed / Lapsed |