US3854751A
Expired / Lapsed
US
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Method for rapidly switching a display by sequential application of orthogonal electric fields to a liquid crystal material having optical properties of the nematic mesophase
Assignee: Xerox Corp
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Filing: 1973-04-09
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Granted: 1974-12-17
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Expires: 1993-04-09
Abstract
Abstract A liquid crystalline composition having optical uniaxiality is driven by electrical fields to alternate its optic axis between substantially normal positions of orientation. Imaging at speeds greater than 500 cycles per second are achieved with enhanced imaging contrast.
Inventors
- 👤 W Haas
- 👤 J Adams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:51
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/137; G02F1/13731; G02F1/133
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
91 words
An electro-optic method, comprising: a. providing a layer of liquid crystalline substance having the optical properties of the nematic mesophase optical uniaxial state; b. applying a first electrical field substantially normal to the optic axis of said substance, wherein the optic axis of said substance is rotated substantially parallel to said first electrical field; and c. removing said first electrical field and then applying a second electrical field substantially normal to the direction of said first electrical field, wherein the optic axis is rotated substantially parallel to said second electrical field.
Claim 2
Dependent Claim
91 words
An electro-optic method, comprising: a. providing a layer of liquid crystalline substance having the optical properties of the nematic mesophase optical uniaxial state; b. applying a first electrical field substantially normal to the optic axis of said substance, wherein the optic axis of said substance is rotated substantially parallel to said first electrical field; and c. removing said first electrical field and then applying a second electrical field substantially normal to the direction of said first electrical field, wherein the optic axis is rotated substantially parallel to said second electrical field.
Claim 3
Dependent Claim
68 words
The method of claim 1 wherein said step (a) comprises providing a liquid crystalline substance exhibiting phase transformation characteristics of the cholesteric mesophase, said substance being under the influence of an applied electrical field at or above the cholestericnematic phase transition level for said material, and wherein said first and second electrical fields in steps (b) and (c) respectively, are applied at or above said phase transition level.
Claim 4
Dependent Claim
24 words
The method of claim 2 wherein said liquid crystalline substance exhibiting phase transformation characteristics of the cholesteric mesophase comprises a cholesteric liquid crystalline material.
Claim 5
Dependent Claim
17 words
The method of claim 3 wherein said liquid crystalline substance further comprises a nematic liquid crystalline material.
Claim 6
Dependent Claim
23 words
The method of claim 4 wherein said liquid crystalline substance comprises by weight about 80 percent methoxybenzylidene-p-n-butylaniline and about 20 percent cholesteryl chloride.
Claim 7
Dependent Claim
17 words
The method of claim 3 wherein said liquid crystalline substance further comprises a smectic liquid crystalline material.
Claim 8
Dependent Claim
33 words
The method of claim 2 wherein said liquid crystalline substance exhibiting phase transformation characteristics of the cholesteric mesophase comprises a mixture of a nematic liquid crystalline material and an optically active non-mesomorphic material.
Claim 9
Dependent Claim
21 words
The method of claim 7 wherein said optically active non-mesomorphic material is selected from the group consisting of l-menthol and d-camphor.
Claim 10
Dependent Claim
30 words
The method of claim 2 wherein said steps (a), (b) and (c) applied electrical fields have an electrical field strength of from about 103 to about 105 volts per centimeter.
Claim 11
Dependent Claim
27 words
The method of claim 2 wherein said liquid crystalline substance comprises a mixture by weight of about 60 percent cholesteryl chloride and about 40 percent cholesteryl nonanoate.
Claim 12
Dependent Claim
17 words
The method of claim 1 wherein said liquid crystalline substance comprises a compensated cholesteric liquid crystalline mixture.
Claim 13
Dependent Claim
29 words
The method of claim 11 wherein said compensated cholesteric liquid crystalline mixture comprises about 50 percent by weight cholesteryl chloride and about 50 percent by weight oleyl cholesteryl carbonate.
Claim 14
Dependent Claim
16 words
The method of claim 1 wherein said liquid crystalline substAnce comprises a nematic which spontaneously aligns.
Claim 15
Dependent Claim
27 words
The method of claim 1 further including, after sequential performance of steps (b) and (c), the step of repeating sequentially steps (b) and (c) at least once.
Claim 16
Dependent Claim
31 words
The method of claim 14 wherein steps (b) and (c) are repeated at a rate which produces an imaging speed of from between about 1 to about 500 cycles per second.
Claim 17
Dependent Claim
19 words
The method of claim 15 wherein said imaging speed is from about 100 to about 200 cycles per second.
Claim 18
Dependent Claim
14 words
The method of claim 1 additionally comprising providing the liquid crystalline composition between polarizers.
Claim 19
Dependent Claim
34 words
The method of claim 17 wherein said polarizers are crossed at about 90* and make an angle of about 45* with at least one of the electrical fields applied in steps (b) and (c).
Claim 20
Dependent Claim
26 words
The method of claim 1 wherein said liquid crystalline substance is in layer configuration having a layer thickness from about 1 micron to about 50 microns.
Claim 21
Dependent Claim
29 words
The method of claim 1 wherein said electrical fields in steps (b) and (c) have an electrical field strength of from about 103 to about 105 volts per centimeter.
Claim 22
Dependent Claim
39 words
The method of claim 1 wherein said electrical fields in steps (b) and (c) are applied between electrodes in contact with said liquid crystalline substance and wherein said electrode thicknesses are from about 50 angstroms to about 10 microns.
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) | 1977-12-16 | 1978-06-17 | 1978-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-16 | 1982-06-17 | 1982-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-16 | 1986-06-17 | 1986-12-17 | $7700.00 | Window Closed / Lapsed |