Patent US2045745A successfully refreshed from Google Patents.
EP0283916A2
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EP
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Liquid crystal light-modulating device imparted with memory effect and display unit utilizing same
Assignee: Hitachi Ltd
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Filing: 1988-03-16
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Granted: —
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Expires: 2008-03-16
Abstract
Abstract There are disclosed a ferroelectric liquid crystal light-modulating device comprising a pair of base plates each provided with an electrode, at least one of which is transparent, and a light-polarizing means, said base plates being arranged with a gap therebetween to form a cell which contains a ferroelectric liquid crystal composition, which device is characterized by being such that said ferroelectric liquid crystal composition exhibits a phase sequence in which a smectic A (SA) phase is in the higher temperature side of an adjacent ferroelectric phase [smectic C* (SC*) phase] and either (a) the elastic constant (B1) in deformation of C-director in the liquid crystal layer conforms to the formula, B1 > 1.0 x 10<-><1><0> N or (b) said liquid crystal composition has a spontaneous polarization larger than 3.2 x 10<-><4> C/m<2>; and a display device using said ferroelectric liquid crystal light-modulating device.
Inventors
- 👤 Katsumi Kondo
- 👤 Hisao Yokokura
- 👤 Teruo Kitamura
- 👤 Yasuo Hanawa
- 👤 Kishiro Iwasaki
- 👤 Tadao Nakata
- 👤 Masato Isogai
- 👤 Akio Mukoh
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 08:49
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/137; G02F1/139; G02F1/141
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
119 words
A ferroelectric liquid crystal light-modulating device comprising a pair of base plates each provided with an electrode, at least one of which is transparent, and a light-polarizing means, said base plates being arranged with a gap therebetween to form a cell which contains a ferroelectric liquid crystal composition, which device is characterized by being such that said ferroelectric liquid crystal composition exhibits a phase sequence in which a smectic A (S A ) phase is in the higher temperature side of an adjacent ferroelectric phase [smectic C * (S c * ) phase ] and the elastic constant (B,) in deformation of C-director in the liquid crystal layer conforms to the formula B, > 1.0 × 10 -10 N.
Claim 2
Dependent Claim
119 words
A ferroelectric liquid crystal light-modulating device comprising a pair of base plates each provided with an electrode, at least one of which is transparent, and a light-polarizing means, said base plates being arranged with a gap therebetween to form a cell which contains a ferroelectric liquid crystal composition, which device is characterized by being such that said ferroelectric liquid crystal composition exhibits a phase sequence in which a smectic A (S A ) phase is in the higher temperature side of an adjacent ferroelectric phase [smectic C * (S c * ) phase ] and the elastic constant (B,) in deformation of C-director in the liquid crystal layer conforms to the formula B, > 1.0 × 10 -10 N.
Claim 3
Dependent Claim
100 words
A ferroelectric liquid crystal light-modulating device comprising a pair of base plates each provided with an electrode, at least one of which is transparent, and a light-polarizing means, said base plates being arranged with a gap therebetween to form a cell which holds a ferroelectric liquid crystal composition, which device is characterized by being such that said ferroelectric liquid crystal composition exhibits a phase sequence in which a smectic A(S A ) phase is in the higher temperature side of an adjacent ferroelectric phase (smectic C * phase) and has a spontaneous polarization larger than 3.2 × 10 -4 C/m2.
Claim 4
Dependent Claim
100 words
A ferroelectric liquid crystal light-modulating device comprising a pair of base plates each provided with an electrode, at least one of which is transparent, and a light-polarizing means, said base plates being arranged with a gap therebetween to form a cell which holds a ferroelectric liquid crystal composition, which device is characterized by being such that said ferroelectric liquid crystal composition exhibits a phase sequence in which a smectic A(S A ) phase is in the higher temperature side of an adjacent ferroelectric phase (smectic C * phase) and has a spontaneous polarization larger than 3.2 × 10 -4 C/m2.
Claim 5
Dependent Claim
128 words
A display comprising a liquid crystal, light-polarizing means, transparent electrode, and base plate, which is characterized by being such that the ferroelectric liquid crystal composition used in said light-modulating element exhibits a phase sequence in which a smectic A (S A ) phase is in the higher temperature side of an adjacent ferroelectric phase (smectic C * phase) and at least the deformation constant (B,) of C-director in the liquid crystal layer conforms to the formula, B, > 1.0 × 10 -10 N or the spontaneous polarization is larger than 3.2 x 10 C/m2 or the deformation constant (B,) of C-director conforms to the formula, B, > 1.0 × 10 -10 N and at the same time the spontaneous polarization is larger than 3.2 x 10 C/ m2.
Claim 6
Dependent Claim
128 words
A display comprising a liquid crystal, light-polarizing means, transparent electrode, and base plate, which is characterized by being such that the ferroelectric liquid crystal composition used in said light-modulating element exhibits a phase sequence in which a smectic A (S A ) phase is in the higher temperature side of an adjacent ferroelectric phase (smectic C * phase) and at least the deformation constant (B,) of C-director in the liquid crystal layer conforms to the formula, B, > 1.0 × 10 -10 N or the spontaneous polarization is larger than 3.2 x 10 C/m2 or the deformation constant (B,) of C-director conforms to the formula, B, > 1.0 × 10 -10 N and at the same time the spontaneous polarization is larger than 3.2 x 10 C/ m2.
Claim 7
Dependent Claim
42 words
A device according to claim 3, wherein at zero electric field a portion of middle part of the liquid crystal layer of the light-modulating element forms a helical structure whose helical axis is parallel to the base plate of the light-modulating element.
Claim 8
Independent Claim
71 words
A device according to any of claims 1 to 4, wherein said composition is the one capable of generating two uniform zones abutting on the respective internal surfaces of the cell in which the molecules of liquid crystal are disposed almost in parallel with said surfaces, and a zone sandwiched between said uniform zones in which the helical structure of the liquid crystal is formed when the electric field is zero.
Claim 9
Dependent Claim
146 words
A ferroelectric liquid crystal light-modulating device comprising a pair of base plates each provided with an electrode, at least one of which is transparent, and a light-polarizing means, said base plates being arranged with a gap therebetween to form a cell which holds a ferroelectric liquid crystal composition, which device is characterized by being such that said ferroelectric liquid crystal composition exhibits a phase sequence in which a smectic A (S A ) phase is in the higher temperature side of an adjacent ferroelectric phase (smectic C * phase) and is capable of generating two uniform zones abutting on the respective internal surfaces of the cell in which the molecules of liquid crystal are disposed almost in parallel with said surfaces, and a zone sandwiched between said uniform zones in which the helical structure of the liquid crystal is formed when the electric field is zero.
Claim 10
Dependent Claim
146 words
A ferroelectric liquid crystal light-modulating device comprising a pair of base plates each provided with an electrode, at least one of which is transparent, and a light-polarizing means, said base plates being arranged with a gap therebetween to form a cell which holds a ferroelectric liquid crystal composition, which device is characterized by being such that said ferroelectric liquid crystal composition exhibits a phase sequence in which a smectic A (S A ) phase is in the higher temperature side of an adjacent ferroelectric phase (smectic C * phase) and is capable of generating two uniform zones abutting on the respective internal surfaces of the cell in which the molecules of liquid crystal are disposed almost in parallel with said surfaces, and a zone sandwiched between said uniform zones in which the helical structure of the liquid crystal is formed when the electric field is zero.
Claim 11
Independent Claim
20 words
A device according to any of claims 1 to 6, wherein the base plates are provided with an orientation-controlling coating.
Claim 12
Dependent Claim
15 words
A device according to claim 7, wherein the base plates have been subjected to rubbing.
Claim 13
Dependent Claim
22 words
A device according to claim 7 or 8, wherein the orientation-controlling coating is a coating of a polymer of the polyimide type.
Claim 14
Independent Claim
18 words
A device according to any of claims 1 to 9, wherein the gap is larger than 3 µm.
Claim 15
Independent Claim
20 words
A device according to any of claims 1 to 10, wherein the ferroelectric liquid crystal composition has a dichromatic property.
Claim 16
Independent Claim
34 words
A device according to any of claims 1 to 11, wherein the ferroelectric liquid crystal composition contains a ferroelectric liquid crystal compound having a spontaneous polarization larger than 3.2 × 10 -4 C/ m2.
Claim 17
Independent Claim
46 words
A device according to any of claims 1 to 12, wherein the ferroelectric liquid crystal compound has a chemical structure such that there is no methylane or polymethylane group between the portion called hard rod core which contains an aromatic ring, and the asymetric carbon atom.
Claim 18
Dependent Claim
64 words
A device according to claim 13, wherein the ferroelectric liquid crystal compound is a compound represented by the formula wherein R 1 is a C6 10 -alkyl or -alkoxy, R 2 is a C. , o -alkyl, X is -CO 2 -, -OCO, or -CH 2 O-, Y is -0-or -CO 2 -, and m and n are an integer of 1 or 2.
Claim 19
Dependent Claim
25 words
A device according to claim 14, wherein the compound represented by the formula [I] is, and/or wherein n is an integer of 6 to 10.
Claim 20
Independent Claim
33 words
A device according to any of claims 1 to 15, wherein the ferroelectric liquid crystal composition contains a ferroelectric liquid crystal compound having a helical pitch smaller than one-fifth of the cell thickness.
Claim 21
Dependent Claim
24 words
A device according to claim 16, wherein the helical pitch of the ferroelectric liquid crystal composition is smaller than one-fifth of the cell thickness.
Claim 22
Dependent Claim
35 words
A device according to claim 16, wherein the spontaneous polarization of the ferroelectric liquid crystal compound having a helical pitch smaller than one-fifth of cell thickness is below 3.2 × 10 -4 C/m 2 .
Claim 23
Dependent Claim
17 words
A device according to claim 18, wherein the ferroelectric liquid crystal compound is represented by the formula
References Cited (Backward Citations)
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