US4773738A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical modulation device using ferroelectric liquid crystal and AC and DC driving voltages
Assignee: Canon Inc
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Filing: 1987-08-25
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Granted: 1988-09-27
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Expires: 2007-08-25
Abstract
Abstract An optical modulation device includes: a ferroelectric liquid crystal disposed between a pair of substrates; provision for applying an alternating voltage sufficient to render the ferroelectric liquid crystal turbid; and provision for superposing a DC voltage on the alternating voltage. A portion of the ferroelectric liquid crystal rendered turbid through the application of an alternating voltage is selectively caused to have an increased transmittance when superposed with a DC voltage.
Inventors
- 👤 Naoji Hayakawa
- 👤 Fumitaka Kan
- 👤 Toshiaki Majima
- 👤 Masanori Takenouchi
- 👤 Ichiro Nomura
- 👤 Mitsuru Yamamoto
- 👤 Hidetoshi Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:54
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G3/3611; G09G3/3622; G09G3/3629; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/137; G02F1/139; G02F1/141; G02F1/133; G02F1/13306; G02F1/13756; G09G2310/00; G09G2310/06; G09G2320/00; G09G2320/02; G09G2320/0209; G09G3/2007; G09G3/2011
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
40 words
An optical modulation device, comprising: a ferroelectric liquid crystal disposed between a pair of substrates; means for applying an alternating voltage sufficient to render the ferroelectric liquid crystal turbid; and means for superposing a DC voltage on the alternating voltage.
Claim 2
Dependent Claim
40 words
An optical modulation device, comprising: a ferroelectric liquid crystal disposed between a pair of substrates; means for applying an alternating voltage sufficient to render the ferroelectric liquid crystal turbid; and means for superposing a DC voltage on the alternating voltage.
Claim 3
Dependent Claim
17 words
A device according to claim 1, which comprises means for varying the magnitude of the DC voltage.
Claim 4
Dependent Claim
21 words
A device according to claim 1, which comprises means for controlling ON or OFF of the application of the DC voltage.
Claim 5
Dependent Claim
18 words
A device according to claim 1, wherein said alternating voltage has a frequency of 2 KHz or below.
Claim 6
Dependent Claim
19 words
A device according to claim 1, wherein said alternating voltage has a frequency of 200 Hz to 2 KHz.
Claim 7
Dependent Claim
17 words
A device according to claim 1, wherein said ferroelectric liquid crystal is a chiral smectic liquid crystal.
Claim 8
Dependent Claim
28 words
A device according to claim 6, wherein said ferroelectric liquid crystal is disposed in a layer having a thickness in the range of 10 μm to 200 μm.
Claim 9
Dependent Claim
70 words
An optical modulation device, comprising: a first substrate having successively thereon a first conductor film, a dielectric film and a second conductor film; a second substrate having thereon a third conductive film; a ferroelectric liquid crystal disposed between the first and second substrates; means for applying an AC voltage between the first and third conductor films; and means for applying a DC voltage between the second and third conductor films.
Claim 10
Dependent Claim
70 words
An optical modulation device, comprising: a first substrate having successively thereon a first conductor film, a dielectric film and a second conductor film; a second substrate having thereon a third conductive film; a ferroelectric liquid crystal disposed between the first and second substrates; means for applying an AC voltage between the first and third conductor films; and means for applying a DC voltage between the second and third conductor films.
Claim 11
Dependent Claim
22 words
A device according to claim 8, which comprises means for varying the DC voltage applied between the second and third conductor films.
Claim 12
Dependent Claim
20 words
A device according to claim 8, wherein said second conductor film is disposed in a plurality insulated from each other.
Claim 13
Dependent Claim
18 words
A device according to claim 8, wherein said AC voltage has a frequency of 2 KHz or below.
Claim 14
Dependent Claim
17 words
A device according to claim 8, wherein said ferroelectric liquid crystal is a chiral smectic liquid crystal.
Claim 15
Dependent Claim
29 words
A device according to claim 12, wherein said chiral smectic liquid crystal is disposed in a layer having a thickness in the range of 10 μm to 200 μm.
Claim 16
Dependent Claim
82 words
An optical modulation device, comprising: a ferroelectric liquid crystal disposed between a pair of substrates; means for applying an alternating voltage sufficient to render the ferroelectric liquid crystal turbid; a matrix electrode arrangement comprising a plurality of scanning electrodes and a plurality of signal electrodes intersecting with the scanning electrodes disposed on the inner sides of said pair of substrates, respectively; and means for applying a DC voltage at an intersection of a selected scanning electrode and at least one signal electrode.
Claim 17
Dependent Claim
82 words
An optical modulation device, comprising: a ferroelectric liquid crystal disposed between a pair of substrates; means for applying an alternating voltage sufficient to render the ferroelectric liquid crystal turbid; a matrix electrode arrangement comprising a plurality of scanning electrodes and a plurality of signal electrodes intersecting with the scanning electrodes disposed on the inner sides of said pair of substrates, respectively; and means for applying a DC voltage at an intersection of a selected scanning electrode and at least one signal electrode.
Claim 18
Dependent Claim
64 words
A device according to claim 14, wherein one of said pair of substrates is successively provided thereon with an auxiliary electrode covering the whole area or a prescribed region of the substrate, a dielectric film, and first stripe electrodes; the other substrate is provided thereon with second stripe electrodes; and the alternating voltage is applied between the auxiliary electrode and the second stripe electrodes.
Claim 19
Dependent Claim
23 words
A device according to claim 15, wherein said first stripe electrodes constitute the signal electrodes and said second stripe electrodes constitute scanning electrodes.
Claim 20
Dependent Claim
32 words
A device according to claim 16, wherein said first stripe electrodes are disposed to have a width which is smaller than a spacing between an adjacent pair of the first stripe electrodes.
Claim 21
Dependent Claim
33 words
A device according to claim 16, wherein said signal electrodes are supplied with pulse voltage signals having a peak value, a pulse duration or a number of pulses depending on given gradation data.
Claim 22
Dependent Claim
18 words
A device according to claim 14, wherein said alternating voltage has a frequency of 2 KHZ or below.
Claim 23
Dependent Claim
17 words
A device according to claim 14, wherein said ferroelectric liquid crystal is a chiral smectic liquid crystal.
Claim 24
Dependent Claim
29 words
A device according to claim 20, wherein said chiral smectic liquid crystal is disposed in a layer having a thickness in the range of 10 μm to 200 μm.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-09-27 | 1992-03-28 | 1992-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-27 | 1996-03-28 | 1996-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-27 | 2000-03-28 | 2000-09-27 | $7700.00 | Window Closed / Lapsed |