Patent US3660818A successfully refreshed from Google Patents.
US3660818A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electro-optical memory
Assignee: RCA Corp
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Filing: 1970-05-04
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Granted: 1972-05-02
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Expires: 1990-05-04
Abstract
Abstract Information is optically written onto the electrically charged surface of a transparent storage medium by directing light modulated with this information at this surface. The light partially discharges the charge and creates an electrical charge pattern which remains stored for long periods. The light either may be scanned across the surface to achieve sequential information storage or may be employed to write a large amount of information in parallel, for example in the form of a hologram. The stored information may be optically recovered by directing polarized light at the storage medium and employing a suitably oriented analyzer or, in the case of hologram storage, by wavefront reconstruction.
Inventors
- 👤 Juan Jose Amodei
- 👤 Richard Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:50
CPC Classifications
G; G11; G11C; G11C13/00; G11C13/04; G11C13/047; G02; G02F; G02F1/00; G02F1/01; G02F1/03; G02F1/05; G02F1/0525; G02F1/0533
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
92 words
A storage system comprising, in combination: a transparent, light responsive element of the type which is capable of storing an electrical charge on its surface; means for applying an electrical charge to said surface; means for writing on said surface comprising means for applying modulated light at relatively high intensity to said surface for selectively discharging said charge; and means for reading from said surface comprising means for applying light at relatively low intensity to said surface and means receptive of said light from said element and responsive to a parameter thereof.
Claim 2
Dependent Claim
92 words
A storage system comprising, in combination: a transparent, light responsive element of the type which is capable of storing an electrical charge on its surface; means for applying an electrical charge to said surface; means for writing on said surface comprising means for applying modulated light at relatively high intensity to said surface for selectively discharging said charge; and means for reading from said surface comprising means for applying light at relatively low intensity to said surface and means receptive of said light from said element and responsive to a parameter thereof.
Claim 3
Dependent Claim
18 words
A storage system as set forth in claim 1 wherein said element is formed of a ferroelectric material.
Claim 4
Dependent Claim
23 words
A storage system as set forth in claim 1 wherein said element comprises a high resistivity surface region on a low resistivity substrate.
Claim 5
Dependent Claim
21 words
A storage system as set forth in claim 1 wherein said element comprises a photoconductive film on a high conductivity substrate.
Claim 6
Dependent Claim
41 words
A storage system as set forth in claim 1 wherein said means for reading includes a source of linearly polarized light and an analyzer oriented to distinguish those portions of the polarized light passing through differently charged regions of said surface.
Claim 7
Dependent Claim
27 words
A storage system as set forth in claim 1 wherein said means for writing comprises means for applying to said surface an interference pattern representing a hologram.
Claim 8
Dependent Claim
45 words
A storage system as set forth in claim 6 wherein said means for reading comprises means for applying coherent light to said surface for reconstructing the image stored as an electrical charge hologram, and means at the position of said image for receiving the same.
Claim 9
Dependent Claim
27 words
A storage system as set forth in claim 1 wherein said means for charging comprises a high voltage source for creating a corona discharge to said surface.
Claim 10
Dependent Claim
28 words
A storage system as set forth in claim 1 wherein said means for charging comprises a source of electrons and means for directing said electrons at said surface.
Claim 11
Dependent Claim
49 words
A storage system as set forth in claim 2 wherein said means for writing on said surface includes means for heating said ferroelectric material to a temperature just above its Curie temperature and for then permitting said ferroelectric material to cool to a temperature lower than the Curie temperature.
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) | 1975-05-02 | 1975-11-01 | 1976-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-02 | 1979-11-01 | 1980-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-02 | 1983-11-01 | 1984-05-02 | $7700.00 | Window Closed / Lapsed |