US4051465A
Expired / Lapsed
US
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Ferroelectric ceramic devices
Assignee: United States Department of the Army
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Filing: 1974-12-16
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Granted: 1977-09-27
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Expires: 1994-12-16
Abstract
Abstract A method and apparatus is disclosed by which high voltage and current can produced by a polycrystalline ferroelectric ceramic material in response to incident light. Numerous applications of the ferroelectric ceramic material taking advantage of such properties thereof are further disclosed. The polycrystalline ferroelectric ceramic material is initially poled by the application thereto of a pulse of voltage of predetermined magnitude and direction. After being poled in such fashion, the application of light impinging on the various surfaces of the ferroelectric ceramic material will induce a consistant high voltage between select surfaces of the ferroelectric ceramic material. Upon disposing electrodes in conductive contact with the material, a current can be generated to a load attached thereacross. Importantly, the magnitude of the voltage produced upon the application of incident light is directly proportional to the remanent polarization of the ferroelectric ceramic material, and is further directly proportional to the length of the material, the polarity of the high voltage being dependent upon the polarity of the remanent polarization and being capable of being reversed when the remanent polarization is reversed. The open circuit voltages produced by the ferroelectric ceramic material are orders of magnitude higher than those which typically have been produced in the prior-art through the utilization of standard photovoltaic materials.
Inventors
- 👤 Philip S. Brody
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:48
CPC Classifications
H; H10; H10F; H10F10/00; G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/135; G02F1/1358; G11; G11C; G11C13/00; G11C13/04; G11C13/047; G21; G21H; G21H1/00; G21H1/12; H10F10/10; Y; Y02; Y02E; Y02E10/00; Y02E10/50
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
98 words
A photovoltaic memory apparatus comprising: a substrate of a ferroelectric ceramic; means for selectively applying a voltage pulse of a predetermined polarity across a region of said substrate to thereby effect a remanent ferroelectric polarization in said region of said substrate representative of the information to be stored; means for selectively illuminating said poled region of said substrate with a source of radiation, whereby a photovoltaic voltage is produced at said region of a polairy dependent upon said predetermined polarity of said polarizing voltage pulse; and means for detecting said photovoltaic voltage whereby the stored information is retrieved.
Claim 2
Dependent Claim
98 words
A photovoltaic memory apparatus comprising: a substrate of a ferroelectric ceramic; means for selectively applying a voltage pulse of a predetermined polarity across a region of said substrate to thereby effect a remanent ferroelectric polarization in said region of said substrate representative of the information to be stored; means for selectively illuminating said poled region of said substrate with a source of radiation, whereby a photovoltaic voltage is produced at said region of a polairy dependent upon said predetermined polarity of said polarizing voltage pulse; and means for detecting said photovoltaic voltage whereby the stored information is retrieved.
Claim 3
Dependent Claim
75 words
A memory apparatus as defined in claim 1, wherein an array of electrode pairs are disposed on opposing sides of said substrate to define a matrix configuration of poled regions, said polarizing voltage pulse being applied across selected electrode pairs, and wherein said information reading means scans said matrix configuration in accordance with a desired pattern, said detecting means being coupled to said array of electrode pairs and being synchronized with said information reading means.
Claim 4
Dependent Claim
47 words
A memory apparatus as defined in claim 1, wherein said substrate is sandwiched between at least one electrode pair and one electrode of said electrode pair is transparent such that said illumination from said information reading means passes therethrough into said respective poled region of said substrate.
Claim 5
Independent Claim
134 words
A method of addressing and storing information utilizing a substrate of a ferroelectric ceramic as a memory core, said method comprising the steps of initially effecting a remanent electrical polarization in regions of the ferroelectric ceramic by the application of a voltage pulse across the regions of the substrate, the voltage pulse having at least one of a polarity and magnitude representative of the information to be stored; addressing the memory core while illuminating the polarized regions of the ferroelectric ceramic substrate with a source of radiation; and detecting at least one of the polarity and magnitude of the photovoltaic current and voltage produced by such illumination upon the polarized regions, the polarity and magnitude beng dependent upon the polarity and magnitude of the initial polarizing voltage pulse whereby the stored information is recovered.
Claim 6
Independent Claim
134 words
A method of addressing and storing information utilizing a substrate of a ferroelectric ceramic as a memory core, said method comprising the steps of initially effecting a remanent electrical polarization in regions of the ferroelectric ceramic by the application of a voltage pulse across the regions of the substrate, the voltage pulse having at least one of a polarity and magnitude representative of the information to be stored; addressing the memory core while illuminating the polarized regions of the ferroelectric ceramic substrate with a source of radiation; and detecting at least one of the polarity and magnitude of the photovoltaic current and voltage produced by such illumination upon the polarized regions, the polarity and magnitude beng dependent upon the polarity and magnitude of the initial polarizing voltage pulse whereby the stored information is recovered.
Claim 7
Dependent Claim
127 words
An optical apparatus comprising in combination: an electro-optic means providing variable light transmission characteristics in response to the magnitude and polarity of an applied voltage; a substrate of a ferroelectric ceramic; means for applying a polarizing voltage pulse of a predetermined magnitude and polarity across said substrate to effect a remanent electrical polarization within said substrate; means for illuminating said electro-optic means and said ceramic substrate, ilumination impinging upon said substrate effecting the generation by said substrate of a photovoltaic current and voltage having a polarity dependent upon the polarity of said polarizing voltage pulse; and means for applying said generated photovoltaic voltage to said electro-optic means, whereby the transmission characteristics of said electro-optic means to the illumination impinging thereon is varied to effect a visual display.
Claim 8
Dependent Claim
127 words
An optical apparatus comprising in combination: an electro-optic means providing variable light transmission characteristics in response to the magnitude and polarity of an applied voltage; a substrate of a ferroelectric ceramic; means for applying a polarizing voltage pulse of a predetermined magnitude and polarity across said substrate to effect a remanent electrical polarization within said substrate; means for illuminating said electro-optic means and said ceramic substrate, ilumination impinging upon said substrate effecting the generation by said substrate of a photovoltaic current and voltage having a polarity dependent upon the polarity of said polarizing voltage pulse; and means for applying said generated photovoltaic voltage to said electro-optic means, whereby the transmission characteristics of said electro-optic means to the illumination impinging thereon is varied to effect a visual display.
Claim 9
Dependent Claim
37 words
A display apparatus as defined in claim 5, wherein the light transmission characteristics of said electro-optic means is switched from a relatively low opacity to a relatively high opacity upon application thereto of said generated photovoltaic voltage.
Claim 10
Dependent Claim
37 words
A display apparatus as defined in claim 5, wherein the light transmission characteristics of said electro-optic means is switched from a relatively high opacity to a relatively low opacity upon application thereto of said generated photovoltaic voltage.
Claim 11
Dependent Claim
41 words
A display apparatus as defined in claim 6, wherein said relatively low opacity is of a value such that said electro-optic means is substantially transparent, said relatively high opacity being of a value such that said electro-optic means is substantially opaque.
Claim 12
Dependent Claim
41 words
A display apparatus as defined in claim 7, wherein said relatively low opacity is of a value such that said electro-optic means is substantially transparent, said relatively high opacity being of a value such that said electro-optic means is substantially opaque.
Claim 13
Dependent Claim
37 words
A display apparatus as defined in claim 5, wherein the magnitude of said polarizing voltage is selected such that the light transmission characteristics of said electro-optic means is switched between varying opacities to define a gray scale.
Claim 14
Dependent Claim
21 words
A display apparatus as defined in claim 33, wherein said electro-optic means is a liquid crystal of the twisted nematic type.
Claim 15
Dependent Claim
21 words
A display apparatus as defined in claim 5, wherein said electro-optic means is a liquid crystal of the color switching type.
Claim 16
Dependent Claim
22 words
A display apparatus as defined in claim 11, wherein said liquid crystal is sandwiched between a light polarizer and a light analyzer.
Claim 17
Dependent Claim
26 words
A display apparatus as defined in claim 5, wherein said electro-optic means and said ferroelectric ceramic substrate are disposed in superposition to define a monolithic structure.
Claim 18
Dependent Claim
105 words
A display apparatus as defined in claim 14, wherein said electro-optic means is a color switching liquid crystal disposed in superposition with said ceramic substrate to define a monolithic structure, and wherein said means for applying a polarizing voltage to said substrate and said means for applying said photovoltaic voltage to said liquid crystal comprises a plurality of electrodes disposed on opposite faces of said structure with said structure being sandwiched therebetween, at least one electrode pair being in contact with said liquid crystal and with said ceramic substrate, respectively; said electrode of said pair which is in contact with said liquid crystal being transparent.
Claim 19
Dependent Claim
105 words
A display apparatus as defined in claim 14, wherein said monolithic structure constitutes a plurality of stacked superposed layers comprising a first transparent electrode, an electro-optic means, a second transparent electrode, said substrate of a ferroelectric ceramic, and a third electrode, said third electrode being coupled to said first electrode, said means for applying said polarizing voltage being defined by said second and third electrodes, said means for applying said generated photovoltaic voltage being defined by said first and second electrodes, and wherein said means for illuminating said electro-optic means and said substrate comprises a light beam directed to impinge upon said first transparent electrode.
Claim 20
Dependent Claim
21 words
A display apparatus as defined in claim 16, wherein said electro-optic means is a liquid crystal of the color switching type.
Claim 21
Dependent Claim
49 words
A display apparatus as defined in claim 16, wherein said plurality of stacked layers futher includes a polarizer disposed over said first transparent electrode, and an analyzer disposed between said second transparent electrode and said ceramic substrate, said electro-optic means being a liquid crystal of the twisted nematic type.
Claim 22
Dependent Claim
48 words
A display apparatus as defined in claim 16, wherein said illumination means comprises a source of polarized light, said plurality of stacked layers including an analyzer disposed between said second transparent electrode and said ceramic substrate, said electro-optic means being a liquid crystal of the twisted nematic type.
Claim 23
Dependent Claim
26 words
A display apparatus as defined in claim 19, wherein said analyzer is disposed in a direction parallel to the plane of polarization of the incident illumination.
Claim 24
Dependent Claim
29 words
A display apparatus as defined in claim 19, wherein said analyzer is disposed so as to be crossed with respect to the plane of polarization of the incident illumination.
Claim 25
Independent Claim
61 words
A method of electrically storing optical information comprising the steps of: projecting an image constituting the optical information onto a sandwich of a ferroelectric ceramic backed by a layer of resistive material to form an illumination pattern thereon; applying a voltage pulse across the sandwich whereby varying remanent polarizations within the ferroelectric ceramic are produced in dependence upon the illumination pattern.
Claim 26
Independent Claim
61 words
A method of electrically storing optical information comprising the steps of: projecting an image constituting the optical information onto a sandwich of a ferroelectric ceramic backed by a layer of resistive material to form an illumination pattern thereon; applying a voltage pulse across the sandwich whereby varying remanent polarizations within the ferroelectric ceramic are produced in dependence upon the illumination pattern.
Claim 27
Dependent Claim
21 words
The method of claim 22, further including the step of readingout the remanent polarizations to thereby extract the stored optical information.
Claim 28
Dependent Claim
39 words
A display apparatus as defined in claim 5, wherein said variation of the transmission characteristics of the electro-optic means ensures that illumination continues to impinge upon said substrate to latch said electro-optical means and maintain said transmission variation thereof.
Claim 29
Independent Claim
66 words
A method of electrically storing optical information comprising the steps of: projecting an image constituting the optical information onto a ferroelectric ceramic layer to form an illumination pattern thereon and thereby alter the resistivity of the ceramic layer in accordance with said pattern; applying a voltage pulse across the ceramic whereby varying remanent polarizations within the ferroelectric ceramic are produced in dependence upon the illumination pattern.
Claim 30
Independent Claim
66 words
A method of electrically storing optical information comprising the steps of: projecting an image constituting the optical information onto a ferroelectric ceramic layer to form an illumination pattern thereon and thereby alter the resistivity of the ceramic layer in accordance with said pattern; applying a voltage pulse across the ceramic whereby varying remanent polarizations within the ferroelectric ceramic are produced in dependence upon the illumination pattern.
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) | 1980-09-26 | 1981-03-28 | 1981-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-26 | 1985-03-28 | 1985-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-26 | 1989-03-28 | 1989-09-27 | $7700.00 | Window Closed / Lapsed |