US3643233A
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Three-dimensional optical read-only memory
Assignee: International Business Machines Corp
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Filing: 1969-01-15
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Granted: 1972-02-15
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Expires: 1989-01-15
Abstract
Abstract A three-dimensional optical read-only memory is composed of a stack of transparent plates composed of either ferroelectric or ferromagnetic materials wherein binary information is stored as domains in each plate. The stack of plates containing the domains allows a polarized source of light to traverse the stack and appear, to a detecting device, as a homogeneous source. When an electromagnetic field is applied across a single plate in the stack, the polarization of the domains in that plate is rotated, creating a birefringence in the material. The polarized source of light is now modulated by such particularly selected plate according to this particular bit pattern of domains. This pattern can be imaged onto an array of detectors. When the electromagnetic field is removed, the disturbed domains return to their original storage states so that the polarized interrogating light reappears as a homogeneous source to all detectors.
Inventors
- 👤 George J Fan
- 👤 James H Greiner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 03:12
CPC Classifications
G; G11; G11C; G11C13/00; G11C13/04
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
158 words
A three-dimensional optical memory comprising an optically serial stack of individual transparent memory planes, each of said memory planes being aligned along a single central axis, each plane comprising a plurality of domains and antiparallel domains representative of binary storage, wherein said domains and antiparallel domains represent binary storage of ones and zeros having a 180* phase relationship with each other in the quiescent state, means for sending a linearly polarized light beam through the entire area of each of said memory planes of said stack during the quiescent state of said memory whereby each linearly polarized light beam is modulated equally by said domains and antipArallel domains, and means for disturbing the phase relationship of all the domains of only a single memory plane whereby the optical properties of such domains are modified, causing a different modulation of said polarized light beam and means for detecting said different modulation of the polarized beam transmitted through the stack.
Claim 2
Dependent Claim
158 words
A three-dimensional optical memory comprising an optically serial stack of individual transparent memory planes, each of said memory planes being aligned along a single central axis, each plane comprising a plurality of domains and antiparallel domains representative of binary storage, wherein said domains and antiparallel domains represent binary storage of ones and zeros having a 180* phase relationship with each other in the quiescent state, means for sending a linearly polarized light beam through the entire area of each of said memory planes of said stack during the quiescent state of said memory whereby each linearly polarized light beam is modulated equally by said domains and antipArallel domains, and means for disturbing the phase relationship of all the domains of only a single memory plane whereby the optical properties of such domains are modified, causing a different modulation of said polarized light beam and means for detecting said different modulation of the polarized beam transmitted through the stack.
Claim 3
Dependent Claim
43 words
The three-dimensional optical memory of claim 1 wherein said memory planes consist of a ferroelectric material and wherein said means for disturbing the domains of a memory plane is an applied electric field selectively applied to a single one of said memory planes.
Claim 4
Dependent Claim
43 words
The three-dimensional optical memory of claim 1 wherein said memory planes consist of a magnetic material and wherein said means for disturbing the domains of a memory plane is an applied magnetic field selectively applied to a single one of said memory planes.
Claim 5
Dependent Claim
155 words
A three-dimensional optical memory comprising an optically serial stack of individual transparent memory planes, each of said memory planes being aligned along a single central axis, each plane comprising a ferroelectric plate storing domains and antiparallel domains representative of binary information manifesting binary ones and zeros having a 180* phase relationship in the quiescent state, means for sending a linearly polarized light beam through said stack during the quiescent state of said memory whereby such linearly polarized light beam is modulated equally by said domains and antiparallel domains, and means for applying an electric field perpendicular to said domains and antiparallel domains of a selected single memory plane so as to disturb the phase relationship but not switch said domains and antiparallel domains, whereby said polarization light beam is modulated according to the binary pattern of the selected memory plane, and means for sensing the modulated polarized light after its passage through the memory stack.
Claim 6
Dependent Claim
155 words
A three-dimensional optical memory comprising an optically serial stack of individual transparent memory planes, each of said memory planes being aligned along a single central axis, each plane comprising a ferroelectric plate storing domains and antiparallel domains representative of binary information manifesting binary ones and zeros having a 180* phase relationship in the quiescent state, means for sending a linearly polarized light beam through said stack during the quiescent state of said memory whereby such linearly polarized light beam is modulated equally by said domains and antiparallel domains, and means for applying an electric field perpendicular to said domains and antiparallel domains of a selected single memory plane so as to disturb the phase relationship but not switch said domains and antiparallel domains, whereby said polarization light beam is modulated according to the binary pattern of the selected memory plane, and means for sensing the modulated polarized light after its passage through the memory stack.
Claim 7
Dependent Claim
173 words
A three-dimensional optical memory comprising an optically serial stack of individual transparent memory planes, each of said memory planes being aligned along a single central axis, each plane comprising a ferroelectric plate storing domains and antiparallel domains representative of binary information manifesting binary ones and zeros having a 180* phase relationship in the quiescent state, means for sending a linearly polarized light beam through said stack during the quiescent state of said memory whereby such linearly polarized light beam is modulated equally by said domains and antiparallel domains, means for applying an electric field perpendicular to said domains and antiparallel domains of a selected single memory plane so as to disturb but not switch the phase relationship of said domains, whereby said polarized beam is modulated according to the binary pattern of the selected memory plane, and said ferroelectric plates being chosen to have a thickness equal to a given number of half-wave lengths of the linearly polarized light beam to maintain said beam linearly polarized throughout its passage through the memory stack.
Claim 8
Dependent Claim
173 words
A three-dimensional optical memory comprising an optically serial stack of individual transparent memory planes, each of said memory planes being aligned along a single central axis, each plane comprising a ferroelectric plate storing domains and antiparallel domains representative of binary information manifesting binary ones and zeros having a 180* phase relationship in the quiescent state, means for sending a linearly polarized light beam through said stack during the quiescent state of said memory whereby such linearly polarized light beam is modulated equally by said domains and antiparallel domains, means for applying an electric field perpendicular to said domains and antiparallel domains of a selected single memory plane so as to disturb but not switch the phase relationship of said domains, whereby said polarized beam is modulated according to the binary pattern of the selected memory plane, and said ferroelectric plates being chosen to have a thickness equal to a given number of half-wave lengths of the linearly polarized light beam to maintain said beam linearly polarized throughout its passage through the memory stack.
Claim 9
Dependent Claim
16 words
The three-dimensional optical memory of claim 1 wherein said memory planes consist of an antiferromagnetic material.
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) | 1975-02-14 | 1975-08-16 | 1976-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-14 | 1979-08-16 | 1980-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-14 | 1983-08-16 | 1984-02-15 | $7700.00 | Window Closed / Lapsed |