US3781830A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Holographic memory with light intensity compensation means
Assignee: RCA Corp
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Filing: 1972-06-23
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Granted: 1973-12-25
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Expires: 1992-06-23
Abstract
Abstract A holographic memory is disclosed in which any one hologram in an array of holograms is illuminated by a reference beam from a respective light-emitting diode in an array of light emitting diodes. An array of photosensors is arranged to receive the ''''1'''' and ''''0'''' binary optical information signals from whichever hologram may be illuminated. Each hologram includes a recording of an extra threshold-setting bit, and an extra thresholdsetting-bit photosensor is included to establish an electrical threshold distinguishing between ''''1'''' and ''''0'''' information signals despite variations in light emission from different light-emitting diodes and holograms.
Inventors
- 👤 Vilkomerson D Raphael
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:42
CPC Classifications
G; G11; G11C; G11C13/00; G11C13/04; G11C13/042
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
164 words
In an optical memory, an array of holograms each storing a respective pattern of ''''1'''' and ''''0'''' binary information bits, and a threshold control bit, an array of information bit photosensors equal to the number of binary information bits in each of said patterns, and a threshold bit photosensor, an array of light-emitting diodes each arranged to supply a reference beam to a respective one of said holograms and to cause an optical read-out of binary information bits to said array of information bit photosensors, and an optical read-out of said threshold bit to said threshold bit photosensor. electrical signal output means including differential amplifiers each having a signal input coupled to a respective information photosensor, and having a threshold signal input, threshold signal means coupled from said threshold photosensor to the threshold signal input of a respective differential amplifier to establish a threshold distinguishing between ''''1'''' and ''''0'''' signal amplitudes despite variations in light emission from said light-emitting diodes and from said holograms.
Claim 2
Dependent Claim
164 words
In an optical memory, an array of holograms each storing a respective pattern of ''''1'''' and ''''0'''' binary information bits, and a threshold control bit, an array of information bit photosensors equal to the number of binary information bits in each of said patterns, and a threshold bit photosensor, an array of light-emitting diodes each arranged to supply a reference beam to a respective one of said holograms and to cause an optical read-out of binary information bits to said array of information bit photosensors, and an optical read-out of said threshold bit to said threshold bit photosensor. electrical signal output means including differential amplifiers each having a signal input coupled to a respective information photosensor, and having a threshold signal input, threshold signal means coupled from said threshold photosensor to the threshold signal input of a respective differential amplifier to establish a threshold distinguishing between ''''1'''' and ''''0'''' signal amplitudes despite variations in light emission from said light-emitting diodes and from said holograms.
References Cited (Backward Citations)
US3020534A
Cited
US3669521A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |