US3855579A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of using an optic relay comprising an element of an electro-optical material and a photosensitive element
Assignee: US Philips Corp
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Filing: 1973-01-15
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Granted: 1974-12-17
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Expires: 1993-01-15
Abstract
Abstract In order to erase an image recorded on an optic relay comprising an element of electro-optical material and a photosensitive element, the photosensitive layer is uniformly exposed and simultaneously is applied to the relay a voltage of a sign opposite to that of the voltage previously applied during the recording and having such a value that during the re-recording the voltage at the terminals of the electro-optical element is zero. Application: Television.
Inventors
- 👤 M Grenot
- 👤 J Pergrale
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 20:06
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/03; G02F1/05; G02F1/0533
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
200 words
A method of using an optic relay in conjunction with at least a first source of light radiation having a first frequency, means for projecting the said radiation, at least a second source of light radiation having a second frequency, polarization and projection means from said second light radiation on an optic image relay constituted by an evacuated space having at least one window which is transparent to the said light radiation, a layer which is photosensitive to the said first radiation, a plate having an electro-optic effect maintained at a temperature near its Curie point and presenting a variable double refraction as a function of a potential difference existing between its faces, a first electrode which is electrically conductive and optically transparent to the said second light radiation being disposed against the said plate and a second electrode being placed on the opposite side in the proximity of the said plate, the method comprising displaying an image of electric charges while projecting an image on the photosensitive layer and in the presence of a voltage V between the electrodes, erasing said charges image while illuminating uniformly the photosensitive layer, and simultaneously applying between the two electrodes a voltage -V''.
Claim 2
Independent Claim
200 words
A method of using an optic relay in conjunction with at least a first source of light radiation having a first frequency, means for projecting the said radiation, at least a second source of light radiation having a second frequency, polarization and projection means from said second light radiation on an optic image relay constituted by an evacuated space having at least one window which is transparent to the said light radiation, a layer which is photosensitive to the said first radiation, a plate having an electro-optic effect maintained at a temperature near its Curie point and presenting a variable double refraction as a function of a potential difference existing between its faces, a first electrode which is electrically conductive and optically transparent to the said second light radiation being disposed against the said plate and a second electrode being placed on the opposite side in the proximity of the said plate, the method comprising displaying an image of electric charges while projecting an image on the photosensitive layer and in the presence of a voltage V between the electrodes, erasing said charges image while illuminating uniformly the photosensitive layer, and simultaneously applying between the two electrodes a voltage -V''.
Claim 3
Dependent Claim
88 words
A method as claimed in claIm 1, characterized in that the applied voltage -V'' has a value -V'' V C''/C, in which C is the capacity of the assembly electro-optical plate-dielectric mirror and C'' is the capacity existing between said assembly and the electrode situated on the side opposite to the plate, in such manner that the voltage at the terminals of the assembly electro-optical plate-dielectric mirror is removed when the voltage V is again applied between the electrodes in the absence of light on the photosensitive layer.
References Cited (Backward Citations)
US3740734A
Cited
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 |