US4119558A
Expired / Lapsed
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Liquid crystal materials
Assignee: UK Secretary of State for Defence
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Filing: 1977-08-04
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Granted: 1978-10-10
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Expires: 1997-08-04
Abstract
Abstract Novel liquid crystal materials are provided having the general formula ##STR1## where A is a 4-alkylphenyl group and B is a 2-(6-alkyl)naphthyl group, or vice versa, wherein the alkyl groups in A and B may be the same or different. These materials have a dielectric anisotropy sign change at moderate frequencies, i.e., in the range 1kHz to 50kHz and are thus useful for twisted nematic device cells of the frequency switching type.
Inventors
- 👤 David Coates
- 👤 George William Gray
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:59
CPC Classifications
C; C09; C09K; C09K19/00; C09K19/04; C09K19/06; C09K19/32; C09K19/322; C07; C07C; C07C43/00; C07C43/02; C07C43/20; C07C43/202; C07C45/00; C07C45/45; C07C45/46; C07C51/00; C07C51/16; C07C51/29
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
48 words
A liquid crystal material which is an aromatic diester having the formula. ##STR8## in which A is a 4-alkylphenyl group and B is a 2-(6-alkyl)naphthyl group or A is a 2-(6-alkyl)naphthyl group and B is a 4-alkylphenyl group wherein the alkyl groups may be the same or different.
Claim 2
Dependent Claim
48 words
A liquid crystal material which is an aromatic diester having the formula. ##STR8## in which A is a 4-alkylphenyl group and B is a 2-(6-alkyl)naphthyl group or A is a 2-(6-alkyl)naphthyl group and B is a 4-alkylphenyl group wherein the alkyl groups may be the same or different.
Claim 3
Dependent Claim
25 words
A liquid crystal material as claimed in claim 1 and wherein the alkyl groups are straight chain alkyl groups having up to ten carbon atoms.
Claim 4
Dependent Claim
26 words
A liquid crystal material as claimed in claim 1 and wherein the alkyl groups are straight chain alkyl groups having from four to ten carbon atoms.
Claim 5
Dependent Claim
23 words
A liquid crystal material as claimed in claim 1 and having a dielectric anisotropy sign reversal in the frequency range 1kHz to 50kHz.
Claim 6
Dependent Claim
36 words
A liquid crystal material which is a diester having the formula: ##STR9## and wherein R and R', which may be the same or different are straight chain alkyl groups having four to seven carbon atoms inclusive.
Claim 7
Dependent Claim
36 words
A liquid crystal material which is a diester having the formula: ##STR9## and wherein R and R', which may be the same or different are straight chain alkyl groups having four to seven carbon atoms inclusive.
Claim 8
Dependent Claim
18 words
A liquid crystal material as claimed in claim 4 and wherein R is n-butyl and R' is n-pentyl.
Claim 9
Dependent Claim
18 words
A liquid crystal material as claimed in claim 4 and wherein R is n-butyl and R' is n-hexyl.
Claim 10
Dependent Claim
18 words
A liquid crystal material as claimed in claim 4 and wherein R is n-pentyl and R' is n-butyl.
Claim 11
Dependent Claim
18 words
A liquid crystal material as claimed in claim 4 and wherein R is n-pentyl and R' is n-pentyl.
Claim 12
Dependent Claim
18 words
A liquid crystal material as claimed in claim 4 and wherein R is n-pentyl and R' is n-hexyl.
Claim 13
Dependent Claim
18 words
A liquid crystal material as claimed in claim 4 and wherein R is n-hexyl and R' is n-butyl.
Claim 14
Dependent Claim
18 words
A liquid crystal material as claimed in claim 4 and wherein R is n-hexyl and R' is n-pentyl.
Claim 15
Dependent Claim
18 words
A liquid crystal material as claimed in claim 4 and wherein R is n-hexyl and R' is n-hexyl.
Claim 16
Dependent Claim
18 words
A liquid crystal material as claimed in claim 4 and wherein R is n-heptyl and R' is n-butyl.
Claim 17
Dependent Claim
18 words
A liquid crystal material as claimed in claim 4 and wherein R is N-heptyl and R' is n-pentyl.
Claim 18
Dependent Claim
21 words
A liquid crystal material which is an aromatic diester having the formula: ##STR10## and wherein R and R' are both n-pentyl.
Claim 19
Dependent Claim
21 words
A liquid crystal material which is an aromatic diester having the formula: ##STR10## and wherein R and R' are both n-pentyl.
Claim 20
Dependent Claim
28 words
A twisted nematic electro-optic display device cell of the frequency switching type wherein the liquid crystal material is a material as claimed in claim 1 or mixtures thereof.
Claim 21
Dependent Claim
37 words
A device cell as claimed in claim 17 and wherein the frequencies employed in the cell are either below 1kHz or above 50kHz, the lower driving frequency being below 1kHz and the higher driving frequency above 50kHz.
Claim 22
Dependent Claim
48 words
An electro-optic display device cell of the twisted nematic type other than a frequency switching device and which includes as its liquid crystal material a material as claimed in claim 1, or a mixture or solution of such materials with a low melting nematogen which is a 4-alkyl-4'-cyanobiphenyl.
Claim 23
Dependent Claim
16 words
A device cell as claimed in claim 19 and wherein the mixture is an eutectic mixture.
Claim 24
Dependent Claim
14 words
A device cell as claimed in claim 19 and wherein the nematogen is 4-n-heptyl-4'-cyanobiphenyl.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-10-09 | 1982-04-10 | 1982-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-09 | 1986-04-10 | 1986-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-09 | 1990-04-10 | 1990-10-10 | $7700.00 | Window Closed / Lapsed |