US3704929A
Expired / Lapsed
US
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Large capacity associative memory employing holography
Assignee: NEC Corp
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Filing: 1970-11-12
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Granted: 1972-12-05
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Expires: 1990-11-12
Abstract
Abstract A large capacity associative memory of the holographic type. Coded information uniquely identifying first data and in the form of spatially modulated coherent light rays, forms an interference pattern with coded information representing second data in the form of spatially modulated coherent light rays and which are related to the first data in a predetermined fashion, as well as with a coherent light beam of relatively narrow cross-section whereby said interference pattern is recorded upon a record plate of photosensitive material in a direction transverse to the surface of the plate. Only that portion of the plate which is exposed to the small cross-section light beam develops the interference pattern, as a result of the use of a saturable die plate positioned in front of the photographic plate to prevent passage of light therethrough except at that area (or those areas) in which the coherent light exceeds a predetermined threshold value. The plate is filled with inter-related first and second data in a point-by-point basis by sequentially scanning the plate with the narrow cross-section beam. Retrieval of data is brought about by directing spatially modulated coherent light beams, representative of the binary information upon the record plate. A first detector array identifies those positions on the record plate which fail to generate primary diffraction images. Using this information, the narrow cross-section coherent light beam is deflected to each of the positions storing a retrieved pattern. Second and third detector arrays detect light spots generated by Braggs reflection which spots respectively represent the interrogation information and the retrieval information related thereto.
Inventors
- 👤 Mitsuhito Sakaguchi
- 👤 Nobuo Nishida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:04
CPC Classifications
G; G11; G11C; G11C15/00; G11C13/00; G11C13/04; G11C13/042; G11C13/045
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
269 words
A hologram associative memory incorporating photosensitive record means and comprising a first light modulating means for spatially modulating a first array of diffused coherent light beams in response to a first multi-bit binary parallel digital information signal to be stored, a second light modulating means for spatially modulating a second array of diffused coherent light beams in response to a second multi-bit binary parallel digital information signal to be stored and having a certain relation with said first information signal, each of said first and second arrays of beams consisting of pairs of beams, there being one pain of beams for each bit in said multi-bit signal, each of said modulating means being operative for each pair of beams to block one of said pair and to transmit the other of said pair depending on the information state of the bit associated with that pair of beams; third means for generating a third signal coherent light beam of narrow cross-section and for deflecting said beam in accordance with an input signal to any one of a plurality of locations on said record means; the illuminated beams of said first, second and third means being directed to intersect each other to form an interference pattern; said photosensitive record means being a substantially planar thick photosensitive plate for photographically recording said interference pattern, said interference pattern being generated in the direction transverse to the surface of said record means; means operable only during the recording operation for permitting the interference pattern to be recorded upon said record means only where said first and second beam arrays intersect with said third beam.
Claim 2
Dependent Claim
269 words
A hologram associative memory incorporating photosensitive record means and comprising a first light modulating means for spatially modulating a first array of diffused coherent light beams in response to a first multi-bit binary parallel digital information signal to be stored, a second light modulating means for spatially modulating a second array of diffused coherent light beams in response to a second multi-bit binary parallel digital information signal to be stored and having a certain relation with said first information signal, each of said first and second arrays of beams consisting of pairs of beams, there being one pain of beams for each bit in said multi-bit signal, each of said modulating means being operative for each pair of beams to block one of said pair and to transmit the other of said pair depending on the information state of the bit associated with that pair of beams; third means for generating a third signal coherent light beam of narrow cross-section and for deflecting said beam in accordance with an input signal to any one of a plurality of locations on said record means; the illuminated beams of said first, second and third means being directed to intersect each other to form an interference pattern; said photosensitive record means being a substantially planar thick photosensitive plate for photographically recording said interference pattern, said interference pattern being generated in the direction transverse to the surface of said record means; means operable only during the recording operation for permitting the interference pattern to be recorded upon said record means only where said first and second beam arrays intersect with said third beam.
Claim 3
Dependent Claim
131 words
The system of claim 1 further comprising means for interrogating said memory with an interrogation signal comprising means for converting the interrogation signal into the binary complement of its associated information signal and applying the binary complement of said interrogation signal to one of said first or second means; first detector means positioned on the side of said record means opposite said light modulating means and being arranged to respectively detect those positions where no first order diffraction images of the third beam are present on said record means when said record means is illuminated by one of said first or second light modulating means; means coupling said detector means to said third means for sequentially illuminating those positions where no first order diffraction images of said third beam are detected.
Claim 4
Dependent Claim
50 words
The system of claim 2 further comprising second detector means positioned to detect the information representative of the pattern generated by the modulating means which has not received the interrogation signal when said record means is illuminated at those positions having no first order diffraction images of said third beam.
Claim 5
Dependent Claim
60 words
The system of claim 3 comprising third detector means positioned to detect the information representative of the pattern generated by the modulating means receiving said interrogation signal when said record means is illuminated by said third beam at those positions having no first order diffraction images of said third beam when said record means is illuminated by said interrogation signal.
Claim 6
Dependent Claim
92 words
The system of claim 2 wherein said detector means is comprised of an array of photosensitive devices each arranged to detect light emanating from an associated position in said record means containing an interference pattern; means coupled to said array for detecting those positions which fail to generate first order diffraction images of said third beam; means coupled to said detector for operating said third means to illuminate those positions which fail to generate first order diffraction images of said third beam when said record means is illuminated by the interrogation signal.
Claim 7
Dependent Claim
39 words
The system of claim 4 wherein said first and second detector means are each comprised of an array of photosensitive devices each arranged to detect light emanating from an associated position in said record means containing an interference pattern.
Claim 8
Independent Claim
325 words
A method for simultaneously storing a large quantity of first information groups and second information groups equal in quantity to said first information groups upon a thick photosensitive record plate wherein each of said first groups is related to an associated one of said second groups comprising the steps of: spatially modulating a first coherent light source in a multi-bit binary digital manner to generate an array of pairs of beams representative of one of said first information groups there being one pair of beams for each binary bit wherein only one beam of each pair is transmitted while the other is blocked dependent upon the state of the binary digital signal associated with the pair of beams; spatially modulating a second coherent light source in a multi-bit binary digital manner to generate an array of pairs of beams representative of one of said second information groups associated therewith there being one pair of beams for each binary bit wherein only one beam of each pair is transmitted while the other is blocked dependent upon the state of the binary digital signal associated with the pair of beams; generating a single coherent beam of small cross-sectional and deflecting said single beam in a predetermined direction in accordance with an input signal to one of a plurality of locations on said photosensitive record plate; the beams of said first and second sources intersecting with said narrow beam to form an interference pattern; positioning the thick planar photosensitive record sheet to record said interference pattern; preventing those portions of said interference pattern below a predetermined threshold level of light intensity from being recorded upon said sheet, said threshold level being chosen to prevent recording of those portions of the interference pattern not including said narrow beam, whereby the portions of the interference pattern having a total intensity above said threshold level are recorded in said plate in a direction transverse to the surface of said record sheet.
Claim 9
Independent Claim
325 words
A method for simultaneously storing a large quantity of first information groups and second information groups equal in quantity to said first information groups upon a thick photosensitive record plate wherein each of said first groups is related to an associated one of said second groups comprising the steps of: spatially modulating a first coherent light source in a multi-bit binary digital manner to generate an array of pairs of beams representative of one of said first information groups there being one pair of beams for each binary bit wherein only one beam of each pair is transmitted while the other is blocked dependent upon the state of the binary digital signal associated with the pair of beams; spatially modulating a second coherent light source in a multi-bit binary digital manner to generate an array of pairs of beams representative of one of said second information groups associated therewith there being one pair of beams for each binary bit wherein only one beam of each pair is transmitted while the other is blocked dependent upon the state of the binary digital signal associated with the pair of beams; generating a single coherent beam of small cross-sectional and deflecting said single beam in a predetermined direction in accordance with an input signal to one of a plurality of locations on said photosensitive record plate; the beams of said first and second sources intersecting with said narrow beam to form an interference pattern; positioning the thick planar photosensitive record sheet to record said interference pattern; preventing those portions of said interference pattern below a predetermined threshold level of light intensity from being recorded upon said sheet, said threshold level being chosen to prevent recording of those portions of the interference pattern not including said narrow beam, whereby the portions of the interference pattern having a total intensity above said threshold level are recorded in said plate in a direction transverse to the surface of said record sheet.
Claim 10
Dependent Claim
46 words
The method of claim 7 further comprising the step of sequentially directing the coherent light beam of small cross-section toward a new position on said plate and modulating said first and second sources with the next set of associated information signals for each new interference pattern.
Claim 11
Dependent Claim
126 words
A method for retrieving information from a plate containing interference patterns developed by the method of claim 7 with an interrogation word comprising the steps of: spatially modulating a first coherent light beam in accordance with the interrogation information which is the complement of one group of either said first or second information and directly illuminating said plate thereby; detecting those positions of said plate which do not generate first order diffraction images of said third beam; sequentially illuminating those positions which do not generate a first order diffraction image of said third beam when said plate is illuminated by the interrogation word, with a coherent light beam of small cross-section; detecting at least one of the groups of information stored at the position being illuminated.
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) | 1975-12-05 | 1976-06-05 | 1976-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-05 | 1980-06-05 | 1980-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-05 | 1984-06-05 | 1984-12-05 | $7700.00 | Window Closed / Lapsed |