Large-capacity associative memory employing holography

Claim 2

An associative memory system employing holographic techniques comprising: a first light wave modulator for spatially modulating diffused coherent light rays in response to data to be stored; a second light wave modulator having means for selectively intercepting, in response to retrieval data given in one-to-one correspondence to said data to be stored, a plurality of parallel coherent light rays; a third light wave modulator for selecting from a plurality of parallel coherent light beams at least one beam to give marking in one-to-one correspondence to each of said data to be stored; a coherent light beam source for directing a thin coherent light beam to an arbitrary direction; and means for recording the interference pattern formed between the output light rays of said light wave modulators and said light beam source only at the spot illuminated by said light beam source; wherein the light wave modulation at said second light wave modulator being such that each bit of said retrieval data is represented by the presence of either of a pair of said parallel light beams and wherein the interference patterns are formed in the recording means in a direction transverse to the plane thereof; and whereby each of said bits of said retrieval data being recorded in the recording means in the form of said interference pattern, by its complementary value.

Claim 3

An associative memory employing holographic techniques wherein at least two space modulated beams are employed to form an interference pattern comprising: a recording plate at least several times as thick as an interference pattern; first means positioned in front of said recording plate for normally preventing light rays from passing therethrough so as to strike said recording plate; second means for generating a coherent light beam of narrow beam width and including means for deflecting said coherent beam to one of a plurality of small regions across said first means to enable light rays striking said first means in the region of said first means illuminated by said coherent light beam to pass therethrough and strike an associated region of said recording plate; a first source of coherent light capable of being spaced modulated by one of a plurality of data plates, which selected data plate is positioned between said first source of coherent light and said recording plate for space modulating light rays emitted from said first source in accordance with data stored in said data plate; third means for generating a plurality of pairs of spaced parallel coherent light rays; said third means including fourth means for modulating said pairs of parallel light rays with binary signals which constitute retrieval data uniquely related to one of said data plates; a first plurality of coherent light marking sources at least equal in number to the number of different data plates and each being physically disposed at a different position in space; means for illuminating only that coherent light source within the first plurality of coherent light sources which is associated with the data plate positioned between said first source and said recording plate; said space modulated light rays generated by a data plate; said selectively modulated pairs of parallel coherent light rays and said selected coherent light marking ray combining to form an interference pattern in said recording plate in the region of said recording plate associated with the region of said first means illuminated by said narrow beam width coherent light beam whereby said interference pattern is disposed in said recording plate in a direction transverse to the surface of said recording plate.

Claim 4

An associative memory employing holographic techniques wherein at least two space modulated beams are employed to form an interference pattern comprising: a recording plate at least several times as thick as an interference pattern; first means positioned in front of said recording plate for normally preventing light rays from passing therethrough so as to strike said recording plate; second means for generating a coherent light beam of narrow beam width and including means for deflecting said coherent beam to one of a plurality of small regions across said first means to enable light rays striking said first means in the region of said first means illuminated by said coherent light beam to pass therethrough and strike an associated region of said recording plate; a first source of coherent light capable of being spaced modulated by one of a plurality of data plates, which selected data plate is positioned between said first source of coherent light and said recording plate for space modulating light rays emitted from said first source in accordance with data stored in said data plate; third means for generating a plurality of pairs of spaced parallel coherent light rays; said third means including fourth means for modulating said pairs of parallel light rays with binary signals which constitute retrieval data uniquely related to one of said data plates; a first plurality of coherent light marking sources at least equal in number to the number of different data plates and each being physically disposed at a different position in space; means for illuminating only that coherent light source within the first plurality of coherent light sources which is associated with the data plate positioned between said first source and said recording plate; said space modulated light rays generated by a data plate; said selectively modulated pairs of parallel coherent light rays and said selected coherent light marking ray combining to form an interference pattern in said recording plate in the region of said recording plate associated with the region of said first means illuminated by said narrow beam width coherent light beam whereby said interference pattern is disposed in said recording plate in a direction transverse to the surface of said recording plate.

Claim 5

The associative memory of claim 2 further comprising; an array of light sensitive devices disposed in space in the same manner as said first plurality of coherent light sources and being positioned behind said recording plate; viewing means positioned behind said recording plate and adjacent said array of light sensitive devices; said array being adapted to means coupled to said array of light sensitive devices for operating said deflecting means to deflect said coherent light beam of narrow beam width to strike a region on said first means which corresponds to that light sensitive device which is not illuminated upon the complement of one of the binary signals applied to said fourth means for data retrieval purposes to thereby display said retrieval data upon said viewing means.

Claim 6

A holographic method for recording data in a recording plate wherein each group of data is contained in a separate data plate comprising the steps of: assigning a binary code to each data plate; spatially modulating a first coherent light source with one of said data plates to direct the space modulated rays toward said recording plate; spatially modulating a second coherent light source into first and second groups of spatially modulated parallel light beams directed toward the recording plate wherein said first group of parallel light beams is modulated in accordance with the binary code assigned to the data plate modulating the first coherent light source and wherein said second group of parallel light beams is modulated by the complement of the binary code; directing the light rays of a third coherent light source toward said recording plate wherein the angle of incidence of the light rays from said third coherent light source is different for each data plate used to spatially modulate the first coherent light source; assigning a different small region of said recording plate to each data plate and enabling only that region assigned to the particular data plate being used to spatially modulate said first coherent light source to be exposed to light rays while preventing all remaining regions from being Exposed to light rays, whereby the interference pattern formed in the recording plate lies in a direction transverse to the surface of the recording plate exposed to the light rays.

Claim 7

A holographic method for recording data in a recording plate wherein each group of data is contained in a separate data plate comprising the steps of: assigning a binary code to each data plate; spatially modulating a first coherent light source with one of said data plates to direct the space modulated rays toward said recording plate; spatially modulating a second coherent light source into first and second groups of spatially modulated parallel light beams directed toward the recording plate wherein said first group of parallel light beams is modulated in accordance with the binary code assigned to the data plate modulating the first coherent light source and wherein said second group of parallel light beams is modulated by the complement of the binary code; directing the light rays of a third coherent light source toward said recording plate wherein the angle of incidence of the light rays from said third coherent light source is different for each data plate used to spatially modulate the first coherent light source; assigning a different small region of said recording plate to each data plate and enabling only that region assigned to the particular data plate being used to spatially modulate said first coherent light source to be exposed to light rays while preventing all remaining regions from being Exposed to light rays, whereby the interference pattern formed in the recording plate lies in a direction transverse to the surface of the recording plate exposed to the light rays.

Claim 8

A method for retrieving data stored in a recording plate in the form of interference patterns generated by the method steps of claim 4 comprising the steps of: i. modulating the first and second groups of parallel light beams by the complement of those binary positions for which retrieval information is desired; ii. illuminating the entire recording plate with the beams generated in step (i); iii. sensing at the rear of said recording plate each region of said recording plate into which data groups have been stored to detect the absence of a light ray passing therethrough; iv. enabling light rays generated by step (i) to sequentially illuminate only those regions on a one-at-a-time basis for which no light ray was detected at each region along the rear of said recording plate; v. observing each of the data groups at the rear of the recording plate.