US5109295A
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Liquid crystal electro-optical device wherein the ferroelectric liquid crystal layer does not form helices when the molecules take two stable states but form helices during the intermediate state
Assignee: Semiconductor Energy Laboratory Co Ltd
•
Filing: 1991-01-28
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Granted: 1992-04-28
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Expires: 2011-01-28
Abstract
Abstract A new type of non-volatile bistable liquid crystal device is disclosed. The device has substrates spaced apart by such a distance that the molecular arrangement of the liquid crystal moaterial is helical and is arranged such that the liquid crystal molecules can selectively take up either of two optically anisotropic stable conditions in dependence puon an applied electric field. The transition between the two stable conditions takes place via an intermediate conditon in which the liquid crystal molecules are reearranged in helical form and represent an optically isotropic condition.
Inventors
- 👤 Masahiko Sato
- 👤 Toshiji Hamatani
- 👤 Toshimitsu Hagiwara
- 👤 Hitoshi Kondou
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 06:46
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/137; G02F1/139; G02F1/141; C; C09; C09K; C09K19/00; C09K19/04; C09K19/06; C09K19/08; C09K19/10; C09K19/20; C09K19/2007; C09K19/2021
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
88 words
A liquid crystal electro-optical device comprising: a pair of substrates spaced apart from each other; an electrode arrangement formed on said pair of substrates; and a ferroelectric liquid crystal layer interposed between said substrates wherein molecules of said ferroelectric liquid crystal layer are capable of being switched between two stable states via an intermediate state in accordance with an electric field applied thereto, wherein said ferroelectric liquid crystal layer does not form helices when the molecules take said two stable states but forms helices during said intermediate state.
Claim 2
Dependent Claim
88 words
A liquid crystal electro-optical device comprising: a pair of substrates spaced apart from each other; an electrode arrangement formed on said pair of substrates; and a ferroelectric liquid crystal layer interposed between said substrates wherein molecules of said ferroelectric liquid crystal layer are capable of being switched between two stable states via an intermediate state in accordance with an electric field applied thereto, wherein said ferroelectric liquid crystal layer does not form helices when the molecules take said two stable states but forms helices during said intermediate state.
Claim 3
Dependent Claim
30 words
A liquid crystal electro-optical device as in claim 1, wherein opposite inner surfaces of said pair of substrates in contact with the liquid crystal layer are comprised of different materials.
Claim 4
Dependent Claim
22 words
A liquid crystal electro-optical device as in claim 2, wherein said opposite inner surfaces are comprised of polyimide and silicon oxide, respectively.
Claim 5
Dependent Claim
24 words
A liquid crystal electro-optical device as in claim 2, wherein said ferroelectric liquid crystal layer exhibits a chiral smectic C phase at operational temperatures.
Claim 6
Dependent Claim
23 words
A liquid crystal electro-optical device as in claim 4, wherein said smectic C phase appears at temperatures ranging from -10° to 70° C.
Claim 7
Dependent Claim
100 words
A liquid crystal electro-optical device comprising: a pair of substrates spaced apart from each other by a predetermined distance; an electrode arrangement formed on said pair of substrates; and a ferroelectric liquid crystal layer interposed between said substrates wherein molecules of said ferroelectric liquid crystal layer are capable of being switched between two stable states via an intermediate state in accordance with an electric field applied thereto, wherein said predetermined distance is selected in order that said ferroelectric liquid crystal layer does not form helices when the molecules take said two stable states but forms helices during said intermediate state.
Claim 8
Dependent Claim
100 words
A liquid crystal electro-optical device comprising: a pair of substrates spaced apart from each other by a predetermined distance; an electrode arrangement formed on said pair of substrates; and a ferroelectric liquid crystal layer interposed between said substrates wherein molecules of said ferroelectric liquid crystal layer are capable of being switched between two stable states via an intermediate state in accordance with an electric field applied thereto, wherein said predetermined distance is selected in order that said ferroelectric liquid crystal layer does not form helices when the molecules take said two stable states but forms helices during said intermediate state.
Claim 9
Dependent Claim
36 words
A liquid crystal electro-optical device as in claim 6, wherein said predetermined distance is substantially larger than a distance of a pitch of said helices and not less than five times the distance of said pitch.
Claim 10
Dependent Claim
155 words
A liquid crystal electro-optical device comprising: a pair of substrates spaced apart from each other; an electrode arrangement formed on said pair of substrates; and a ferroelectric liquid crystal layer interposed between said substrate wherein molecules of said ferroelectric liquid crystal layer are capable of being switched between two stable states via an intermediate state in accordance with an electric field applied thereto, wherein said ferroelectric liquid crystal layer does not form helices when the molecules take said two stable states but forms helices during said intermediate state and wherein said liquid crystal layer comprises a blended liquid crystal material which includes at least one liquid crystal material represented by the general formula: ##STR8## where R stands for an alkyl group comprised of 6-12 carbon constituent atoms; R* stands for an optically active group comprised of 9-15 carbon constituent atoms including at least one asymmetric carbon atom; and 1 represents a numeral 1 or 2.
Claim 11
Dependent Claim
155 words
A liquid crystal electro-optical device comprising: a pair of substrates spaced apart from each other; an electrode arrangement formed on said pair of substrates; and a ferroelectric liquid crystal layer interposed between said substrate wherein molecules of said ferroelectric liquid crystal layer are capable of being switched between two stable states via an intermediate state in accordance with an electric field applied thereto, wherein said ferroelectric liquid crystal layer does not form helices when the molecules take said two stable states but forms helices during said intermediate state and wherein said liquid crystal layer comprises a blended liquid crystal material which includes at least one liquid crystal material represented by the general formula: ##STR8## where R stands for an alkyl group comprised of 6-12 carbon constituent atoms; R* stands for an optically active group comprised of 9-15 carbon constituent atoms including at least one asymmetric carbon atom; and 1 represents a numeral 1 or 2.
Claim 12
Dependent Claim
39 words
A liquid crystal electro-optical liquid crystal electro-optical device as in claim 8, wherein said R, l and R* are as follows: ______________________________________
R 1 R*
______________________________________
C.sub.8 H.sub.17
1
##STR9##
C.sub.12 H.sub.25
1
##STR10##
C.sub.10 H.sub.21
2
##STR11##
______________________________________
Claim 13
Dependent Claim
156 words
A liquid crystal electro-optical device comprising: a pair of substrates spaced apart from each other; an electrode arrangement formed on said pair of substrates; and a ferroelectric liquid crystal layer interposed between said substrates wherein molecules of said ferroelectric liquid crystal layer are capable of being switched between two stable states via an intermediate state in accordance with an electric field applied thereto, wherein said ferroelectric liquid crystal layer does not form helices when the molecules take said two stable states but forms helices during said intermediate state and wherein said liquid crystal layer comprises a blended liquid crystal material which includes at least one liquid crystal material represented by the general formula: ##STR12## where R stands for an alkyl group comprised of 6-12 carbon constituent atoms; R* stands for an optically active group comprised of 9-15 carbon constituent atoms including at least one asymmetric carbon atom; and l, m and n represent a numeral, respectively.
Claim 14
Dependent Claim
156 words
A liquid crystal electro-optical device comprising: a pair of substrates spaced apart from each other; an electrode arrangement formed on said pair of substrates; and a ferroelectric liquid crystal layer interposed between said substrates wherein molecules of said ferroelectric liquid crystal layer are capable of being switched between two stable states via an intermediate state in accordance with an electric field applied thereto, wherein said ferroelectric liquid crystal layer does not form helices when the molecules take said two stable states but forms helices during said intermediate state and wherein said liquid crystal layer comprises a blended liquid crystal material which includes at least one liquid crystal material represented by the general formula: ##STR12## where R stands for an alkyl group comprised of 6-12 carbon constituent atoms; R* stands for an optically active group comprised of 9-15 carbon constituent atoms including at least one asymmetric carbon atom; and l, m and n represent a numeral, respectively.
Claim 15
Dependent Claim
52 words
A liquid crystal electro-optical device as in claim 10 wherein said R, l, n, m and R* are as follows: ______________________________________
R l n m R*
______________________________________
C.sub.8 H.sub.17
1 1 0
##STR13##
C.sub.9 H.sub.19
1 1 1
##STR14##
C.sub.12 H.sub.25
2 1 1
##STR15##
C.sub.10 H.sub.21
2 1 1
##STR16##
______________________________________
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