US4483592A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid crystal optical valve controlled by photoconducting effect
Assignee: Thales SA
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Filing: 1982-04-09
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Granted: 1984-11-20
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Expires: 2002-04-09
Abstract
Abstract A display device is provided using a liquid crystal layer associated with a photoconducting plate, in which the voltage applied to the valve is an AC voltage chosen so as to transfer to the liquid crystal a maximum signal, and that applies more especially to radioscopy and to the projection of coherent (laser reading) or incoherent images.
Inventors
- 👤 Philippe Aubourg
- 👤 Jean P. Huignard
- 👤 Michel Hareng
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 01:07
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/135
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
158 words
A method for producing an image in a liquid crystal device, said device comprising: two electrodes forming a capacitor; a liquid crystal layer between said two electrodes; a photoconductive material plate disposed between said electrodes to one side of said liquid crystal layer; and a transparent support medium on the outside of the electrode which is nearest said liquid crystal layer; and said method for producing an image comprising: receiving optical control radiation by said plate; modulating another source of optical radiation by said layer; determining a first frequency equal to the inverse of the space charge time constant of said photoconductive material; determining a second frequency equal to the frequency at which the voltage transmission ratio as a function of frequency presents a point of inflexion; connecting said electrodes to an AC voltage generator having a frequency that is between a lower limit equal to said first frequency and an upper limit equal to said second frequency.
Claim 2
Independent Claim
158 words
A method for producing an image in a liquid crystal device, said device comprising: two electrodes forming a capacitor; a liquid crystal layer between said two electrodes; a photoconductive material plate disposed between said electrodes to one side of said liquid crystal layer; and a transparent support medium on the outside of the electrode which is nearest said liquid crystal layer; and said method for producing an image comprising: receiving optical control radiation by said plate; modulating another source of optical radiation by said layer; determining a first frequency equal to the inverse of the space charge time constant of said photoconductive material; determining a second frequency equal to the frequency at which the voltage transmission ratio as a function of frequency presents a point of inflexion; connecting said electrodes to an AC voltage generator having a frequency that is between a lower limit equal to said first frequency and an upper limit equal to said second frequency.
Claim 3
Dependent Claim
29 words
The method of claim 16 wherein said liquid crystal layer consists of at least one mesomorphic material disposed with uniform orientation at least in the absence of writing radiation.
References Cited (Backward Citations)
US3592527A
Cited
US3732429A
Cited
US3824002A
Cited
US3960439A
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US4037932A
Cited
FR2404271A1
Cited
GB2005857A
Cited
US4368386A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-11-20 | 1988-05-21 | 1988-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-20 | 1992-05-21 | 1992-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-20 | 1996-05-21 | 1996-11-20 | $7700.00 | Window Closed / Lapsed |