US5093737A
Expired / Lapsed
US
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Method for driving a ferroelectric optical modulation device therefor to apply an erasing voltage in the first step
Assignee: Canon Inc
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Filing: 1989-07-24
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Granted: 1992-03-03
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Expires: 2009-07-24
Abstract
Abstract A method for driving an optical modulation device of the type in which a group of scanning electrodes and a group of signal electrodes are so arranged that picture elements are defined at the intersections therebetween and a bistable optical modulation material assuming either one of two stable states depending an electrical field applied is interposed between the two groups of electrodes, comprising: a first phase in which the bistable optical modulation material at the picture elements on an N-th scanning electrode is oriented to one stable state, a second phase in which a writing signal is applied to the signal electrodes in synchronism with a scanning signal to the N-th scanning electrode and a third phase in which the bistable optical modulation material at the picture elements on an N+1-th scanning electrode is oriented to the one stable state. Also disclosed is another driving mode for an optical modulation device having scanning electrodes, signal electrodes and a bistable optical modulation material interposed between the scanning electrodes and the signal electrode, comprising a first step in which a scanning signal is applied to the whole or a part of the scanning electrodes while, in phase therewith, a signal is applied to the whole or a part of the signal electrodes so that the optical modulation material is oriented to a first stable state, and a second step in which a scanning signal is applied to the whole or a part of the scanning electrodes while in phase therewith, a signal is applied to a selected signal electrode among the whole or a part of the signal electrodes so that the bistable optical modulation material is oriented to a second stable state.
Inventors
- 👤 Junichiro Kanbe
- 👤 Kazuharu Katagiri
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 05:53
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/137; G02F1/13781; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G3/3611; G09G3/3622; G09G3/3629; G09G2310/00; G09G2310/02; G09G2310/0202; G09G2310/0205; G09G2310/06; G09G2320/00; G09G2320/02; G09G2320/0209; G09G3/2007; G09G3/2018
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
219 words
An optical modulation device of the type having a group of scanning electrodes, a group of signal electrodes and a chiral smectic liquid crystal having a first and a second stable state interposed between said group of scanning electrodes and said group of signal electrodes; said optical modulation device employing a driving method having a first step in which a scanning signal is sequentially applied to the whole or a part of the scanning electrodes, a signal is applied to the whole or a part of said signal electrodes so that a voltage of one polarity is applied to the related picture elements on each scanning electrode to orient the chiral smectic liquid crystal to assume the first stable state; and a second step in which a scanning signal is sequentially applied to the whole or a part of the scanning electrodes, a signal is applied to a selected signal electrode among the whole or a part of said signal electrodes so that, on each scanning electrode, a voltage of the other polarity is applied to a selected picture element to orient the chiral smectic liquid crystal to assume the second stable state at the selected picture element, and a voltage not exceeding a threshold voltage of the chiral smectic liquid crystal is applied to the other picture elements.
Claim 2
Dependent Claim
219 words
An optical modulation device of the type having a group of scanning electrodes, a group of signal electrodes and a chiral smectic liquid crystal having a first and a second stable state interposed between said group of scanning electrodes and said group of signal electrodes; said optical modulation device employing a driving method having a first step in which a scanning signal is sequentially applied to the whole or a part of the scanning electrodes, a signal is applied to the whole or a part of said signal electrodes so that a voltage of one polarity is applied to the related picture elements on each scanning electrode to orient the chiral smectic liquid crystal to assume the first stable state; and a second step in which a scanning signal is sequentially applied to the whole or a part of the scanning electrodes, a signal is applied to a selected signal electrode among the whole or a part of said signal electrodes so that, on each scanning electrode, a voltage of the other polarity is applied to a selected picture element to orient the chiral smectic liquid crystal to assume the second stable state at the selected picture element, and a voltage not exceeding a threshold voltage of the chiral smectic liquid crystal is applied to the other picture elements.
Claim 3
Dependent Claim
25 words
The optical modulation device according to claim 1, wherein the chiral smectic liquid crystal is in C, H, I, J, K, G or F phase.
Claim 4
Dependent Claim
20 words
The optical modulation device according to claim 1, wherein the chiral smectic liquid crystal is in C or H phase.
Claim 5
Dependent Claim
32 words
The optical modulation device according to claim 1, wherein the chiral smectic liquid crystal is disposed in a layer thin enough to release the helical structure of the chiral smectic liquid crystal.
Claim 6
Dependent Claim
295 words
An optical modulation device of the type in which a plurality of picture elements are arranged in the form of a matrix having a plurality of rows and a plurality of columns; scanning electrodes arranged in columns and signal electrodes arranged in rows is intersected so as to define each of said plurality of picture elements; a chiral smectic liquid crystal having a first and a second stable state is electrically connected to said plurality of picture elements; and the picture elements in each row are selectively shuttered when the chiral smectic liquid crystal is oriented to assume either one of the first and second stable states; said optical modulation device employing a driving method having a first step in which a scanning signal is sequentially applied to the whole or a part of the scanning electrodes while, in synchronism with the scanning signal, a signal is applied to the whole or a part of said signal electrodes so that a voltage of one polarity is applied to the related picture elements on each scanning electrode to orient the chiral smectic liquid crystal to assume the first stable state; and a second step in which a scanning signal is sequentially applied to the whole or a part of said scanning electrodes while, in synchronism with said scanning signal, a signal is applied to a selected signal electrode among the whole or a part of said signal electrodes so that, on each scanning electrode, a voltage of the other polarity is applied to a selected picture element to orient the chiral smectic liquid crystal to assume the second stable state at the selected picture element, and a voltage not exceeding a threshold voltage of the chiral smectic liquid crystal is applied to the other picture elements.
Claim 7
Dependent Claim
295 words
An optical modulation device of the type in which a plurality of picture elements are arranged in the form of a matrix having a plurality of rows and a plurality of columns; scanning electrodes arranged in columns and signal electrodes arranged in rows is intersected so as to define each of said plurality of picture elements; a chiral smectic liquid crystal having a first and a second stable state is electrically connected to said plurality of picture elements; and the picture elements in each row are selectively shuttered when the chiral smectic liquid crystal is oriented to assume either one of the first and second stable states; said optical modulation device employing a driving method having a first step in which a scanning signal is sequentially applied to the whole or a part of the scanning electrodes while, in synchronism with the scanning signal, a signal is applied to the whole or a part of said signal electrodes so that a voltage of one polarity is applied to the related picture elements on each scanning electrode to orient the chiral smectic liquid crystal to assume the first stable state; and a second step in which a scanning signal is sequentially applied to the whole or a part of said scanning electrodes while, in synchronism with said scanning signal, a signal is applied to a selected signal electrode among the whole or a part of said signal electrodes so that, on each scanning electrode, a voltage of the other polarity is applied to a selected picture element to orient the chiral smectic liquid crystal to assume the second stable state at the selected picture element, and a voltage not exceeding a threshold voltage of the chiral smectic liquid crystal is applied to the other picture elements.
Claim 8
Dependent Claim
25 words
The optical modulation device according to claim 5, wherein the chiral smectic liquid crystal is in C, H, I, J, K, G or F phase.
Claim 9
Dependent Claim
20 words
The optical modulation device according to claim 5, wherein the chiral smectic liquid crystal is in C or H phase.
Claim 10
Dependent Claim
32 words
The optical modulation device according to claim 5, wherein the chiral smectic liquid crystal is disposed in a layer thin enough to release the helical structure of the chiral smectic liquid crystal.
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