Patent US3865975A successfully refreshed from Google Patents.
US3865975A
Expired / Lapsed
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Deep trap, laser activated image converting system
Assignee: National Aeronautics and Space Administration
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Filing: 1973-08-22
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Granted: 1975-02-11
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Expires: 1993-08-22
Abstract
Abstract A system is disclosed for receiving an optical image on the surface of a photoconducting semiconductor, storing the image in deep traps of the semiconductor, and later scanning the semiconductor with a laser beam to empty the deep traps, thereby producing a video signal. The semiconductor is illuminated with photons of energy h nu greater than the band gap DELTA E producing electron-hole pairs in the semiconductor which subsequently fill traps of a depth DELTA Et in energy from the band edges. When the laser beam of low energy photons ( DELTA ET < h nu ' < DELTA E) excites the trapped electrons and holes out of the traps into the conduction and valence bands, a photoconductivity can be observed.
Inventors
- 👤 James C Administrator Fletcher
- 👤 Joseph Maserjian
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:22
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/30
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
229 words
A system for converting an optical image to an electrical video signal comprising a film of semiconductor material having deep level traps, said semiconductor material having a band gap between its conduction band and its valence band of energy Delta E, where said traps are of predetermined energy depth Delta Et for electrons or holes, or electrons and holes, where Delta Et is the larger of said predetermined values for electron and hole traps when both are present, a conductive plate on each side of said film, at least one of said plates being transparent, means for focusing said optical image on said film through a transparent one of said plates, said image having photons of energy h Nu greater than said energy Delta E for producing electron-hole pairs in said semiconductor material for electrons, or holes, or both electrons and holes to be trapped by said deep level trap states, means for producing a high intensity beam of energy h Nu '', where Delta Et < h Nu '' < Delta E, means for deflecting said beam across said semiconductor film through one of said plates, thereby exciting any electrons and holes in said trap states into conduction and valence bands of said semiconductor material, and means connected to said conductive plates for detecting photocurrent produced by any electrons and holes excited into said conduction and valence bands.
Claim 2
Independent Claim
229 words
A system for converting an optical image to an electrical video signal comprising a film of semiconductor material having deep level traps, said semiconductor material having a band gap between its conduction band and its valence band of energy Delta E, where said traps are of predetermined energy depth Delta Et for electrons or holes, or electrons and holes, where Delta Et is the larger of said predetermined values for electron and hole traps when both are present, a conductive plate on each side of said film, at least one of said plates being transparent, means for focusing said optical image on said film through a transparent one of said plates, said image having photons of energy h Nu greater than said energy Delta E for producing electron-hole pairs in said semiconductor material for electrons, or holes, or both electrons and holes to be trapped by said deep level trap states, means for producing a high intensity beam of energy h Nu '', where Delta Et < h Nu '' < Delta E, means for deflecting said beam across said semiconductor film through one of said plates, thereby exciting any electrons and holes in said trap states into conduction and valence bands of said semiconductor material, and means connected to said conductive plates for detecting photocurrent produced by any electrons and holes excited into said conduction and valence bands.
Claim 3
Dependent Claim
22 words
A system as defined in claim 1 wherein said material is selected to have both types of electron and hole trapping states.
Claim 4
Dependent Claim
24 words
A system as defined in claim 1 wherein said material is selecTed to have only one type of said electron and hole trapping states.
Claim 5
Dependent Claim
43 words
A system as defined in claim 1 wherein both of said conductive plates are transparent, and said semiconductor film is scanned with said beam through one of said transparent plates on a side opposite the side on which said optical image is received.
Claim 6
Dependent Claim
43 words
A system as defined in claim 1 wherein only one of said conductive plates is transparent, and said semiconductor film is scanned with said beam through said one of said conductive plates on the same side on which said optical image is received.
Claim 7
Dependent Claim
17 words
A system as defined in claim 1 wherein said means for producing said beam is a laser.
Claim 8
Dependent Claim
22 words
A system as defined in claim 6 wherein said material is selected to have both types of electron and hole trapping states.
Claim 9
Dependent Claim
24 words
A system as defined in claim 6 wherein said material is selected to have only one type of said electron and hole trapping states.
Claim 10
Dependent Claim
43 words
A system as defined in claim 6 wherein both of said conductive plates are transparent, and said semiconductor film is scanned with said beam through one of said transparent plates on a side opposite the side on which said optical image is received.
Claim 11
Dependent Claim
43 words
A system as defined in claim 7 wherein only one of said conductive plates is transparent, and said semiconductor film is scanned with said beam through said one of said conductive plates on the same side on which said optical image is received.
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) | 1978-02-10 | 1978-08-12 | 1979-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-10 | 1982-08-12 | 1983-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-10 | 1986-08-12 | 1987-02-11 | $7700.00 | Window Closed / Lapsed |