Patent US4159539A successfully refreshed from Google Patents.
US4159539A
Expired / Lapsed
US
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Elastic waves device for memorizing information
Assignee: Thales SA
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Filing: 1978-02-03
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Granted: 1979-06-26
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Expires: 1998-02-03
Abstract
Abstract A device for memorizing information by means of interactions between elastic waves and electromagnetic waves. It comprises a piezoelectric substrate, at least one electromechanical transducer receiving the information to be memorized, means for exciting a pulsating electric field through the substrate, said field interacting non-linearly with the elastic wave created by the transducer to form a spatial charge pattern representing said information and means for modifying the physical properties of the medium of propagation of the elastic waves in the region of said pattern, for memorizing. The reading is effected by a non-linear interaction between said pattern and the pulsating electric field.
Inventors
- 👤 Pierre Tournois
- 👤 Charles Maerfeld
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:47
CPC Classifications
G; G11; G11C; G11C27/00; G10; G10K; G10K11/00; G10K11/36; G11C21/00; G11C21/02; G11C21/023; G11C8/00; G11C8/005
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
155 words
A device for memorizing information employing elastic waves, comprising: a piezoelectric substrate; at least one electromechanical transducer deposited on a surface of said substrate, receiving said information in the form of an electric signal and emitting a first elastic wave; first means for exciting a first electromagnetic field through the substrate, said electromagnetic field interacting with said elastic wave so as to produce a time-independent spatial charge pattern in said substrate, representing said information; means for fixing said pattern in said substrate; means for reading said information, constituted by second means for exciting a second electromagnetic field through the substrate, said second field interacting with said pattern so as to produce a second elastic wave, termed a reading wave, having the same characteristics as said first elastic wave but propagating in the opposite direction towards said transducer, said transducer generating an output electrical signal when receiving said reading wave, said output signal representing said information.
Claim 2
Independent Claim
155 words
A device for memorizing information employing elastic waves, comprising: a piezoelectric substrate; at least one electromechanical transducer deposited on a surface of said substrate, receiving said information in the form of an electric signal and emitting a first elastic wave; first means for exciting a first electromagnetic field through the substrate, said electromagnetic field interacting with said elastic wave so as to produce a time-independent spatial charge pattern in said substrate, representing said information; means for fixing said pattern in said substrate; means for reading said information, constituted by second means for exciting a second electromagnetic field through the substrate, said second field interacting with said pattern so as to produce a second elastic wave, termed a reading wave, having the same characteristics as said first elastic wave but propagating in the opposite direction towards said transducer, said transducer generating an output electrical signal when receiving said reading wave, said output signal representing said information.
Claim 3
Dependent Claim
56 words
A device as claimed in claim 1, wherein said first exciation means comprise two electrodes placed on each side of the substrate, at least one of the electrodes being separated from the substrate by an isolating layer, between which electrodes there is applied a pulsating electric signal having the same angular frequency as said elastic wave.
Claim 4
Dependent Claim
29 words
A device as claimed in claim 1, wherein said first means for exciting a first electromagnetic field and said second means for exciting a second electromagnetic field are identical.
Claim 5
Dependent Claim
14 words
A device as claimed in claim 1, wherein said transducer emits elastic surface waves.
Claim 6
Dependent Claim
20 words
A device as claimed in claim 4, wherein said transducer is of the interdigital combs type, having non-rectilinear parallel teeth.
Claim 7
Dependent Claim
14 words
A device as claimed in claim 1, wherein said transducer emits elastic bulk waves.
Claim 8
Dependent Claim
15 words
A device as claimed in claim 6, wherein said transducer comprises electrodes having non-planar surfaces.
Claim 9
Dependent Claim
54 words
A device as claimed in claim 1, wherein said elastic reading wave is subjected to an interaction with a third elastic wave, termed a writing wave, produced by the same transducer and at the same pulsation as said first elastic wave, said interaction producing a second pattern which is fixed by said fixing means.
Claim 10
Dependent Claim
64 words
A device as claimed in claim 4, wherein said means for fixing the pattern are constituted by a dielectric layer placed in facing relation to the surface of the substrate which carries said transducer and without contact with said surface, the dielectric layer being covered in succession with at least one layer of semiconductor and a metallic layer connected to an exterior polarization potential.
Claim 11
Dependent Claim
71 words
A device as claimed in claim 9, wherein said first excitation means comprise two electrodes placed on each side of the substrate, at least one of the electrodes being separated from the substrate by an isolating layer, between which electrodes there is applied a pulsating electric signal having the same pulsation as said elastic wave and wherein one of said electrodes is placed on said metallic layer through an electric insulator.
Claim 12
Dependent Claim
34 words
A device as claimed in claim 9, further comprising a second layer of semiconductor whose conductivity differs from that of the first layer of semiconductor, placed between said first layer and the metallic layer.
Claim 13
Dependent Claim
30 words
A device as claimed in claim 1, wherein said fixing means are constituted by said substrate composed of a piezoelectric ceramic material, said fixing being achieved by a ferroelectric effect.
Claim 14
Dependent Claim
34 words
A device as claimed in claim 1, wherein said fixing means are constituted by said substrate composed of cadmium sulphide (CdS), said fixing being achieved by the effect of traps for the charge carriers.
Claim 15
Dependent Claim
34 words
A device as claimed in claim 1, wherein said fixing means are constituted by said substrate composed of ceramic material of the Yttrium-Aluminium Garnet type (YAG), said fixing being achieved by a magnetoelastic effect.
Claim 16
Dependent Claim
34 words
A device as claimed in claim 1, wherein said fixing means are constituted by said substrate composed of ceramic material of the Yttrium-Iron Garnet type (YIG), said fixing being achieved by a magnetoelastic effect.
Claim 17
Dependent Claim
27 words
A device as claimed in claim 1, comprising a plurality of independent electromechanical transducers, emitting a plurality of elastic wave, respectively corresponding to a plurality of information.
Claim 18
Independent Claim
177 words
A method for memorizing an electric signal by means of an acoustic wave device, said device being of a type that includes: a piezo-electric substrate; at least one electromechanical transducer deposited on a surface of said substrate for generating elastic waves; means for exciting electromagnetic fields through said substrate; means for fixing a charge pattern within said substrate; said method comprising the steps of: producing a first interaction between a first wave, generated by said transducer when receiving said electrical signal to be memorized, termed the first signal, and a first electromagnetic field corresponding to a second electric signal, said first interaction generating a time-independent spatial charge pattern in said substrate, representing said first signal, said pattern being fixed by said fixing means; and producing a second interaction between said pattern and a second electromagnetic field, corresponding to a third electric signal, said second interaction generating a second elastic wave, termed the reading wave, having the same characteristics as said first elastic wave but propagating in the opposite direction towards said transducer which generated said first wave.
Claim 19
Independent Claim
177 words
A method for memorizing an electric signal by means of an acoustic wave device, said device being of a type that includes: a piezo-electric substrate; at least one electromechanical transducer deposited on a surface of said substrate for generating elastic waves; means for exciting electromagnetic fields through said substrate; means for fixing a charge pattern within said substrate; said method comprising the steps of: producing a first interaction between a first wave, generated by said transducer when receiving said electrical signal to be memorized, termed the first signal, and a first electromagnetic field corresponding to a second electric signal, said first interaction generating a time-independent spatial charge pattern in said substrate, representing said first signal, said pattern being fixed by said fixing means; and producing a second interaction between said pattern and a second electromagnetic field, corresponding to a third electric signal, said second interaction generating a second elastic wave, termed the reading wave, having the same characteristics as said first elastic wave but propagating in the opposite direction towards said transducer which generated said first wave.
Claim 20
Independent Claim
19 words
The method of claims 17, wherein said second signal has the same angular frequency as said first elastic wave.
Claim 21
Dependent Claim
15 words
The method of claim 17, wherein said first and second elastic waves are surface waves.
Claim 22
Dependent Claim
15 words
The method of claim 17, wherein said first and second elastic waves are bulk waves.
Claim 23
Dependent Claim
14 words
The method of claim 17, wherein said first elastic wave has non-planar wave fronts.
Claim 24
Dependent Claim
36 words
The method of claim 17, further comprising the following step: generating a fourth electric signal, termed the output signal, by means of said transducer when receiving said reading wave, said output signal representing said first signal.
Claim 25
Dependent Claim
64 words
The method of claim 17, further comprising the following step of: producing a third interaction with a third elastic wave termed a writing wave, corresponding to a fifth electrical signal applied to said electromechanical transducer, said writing wave having the same angular frequency as said first elastic wave, said third interaction producing a further spatial charge pattern, which is fixed by said fixing means.
Claim 26
Independent Claim
216 words
A method of memorizing a plurality of independent signals by means of an acoustic wave device, said device being of a type that includes: a piezo-electric substrate; a plurality of independent electromechanical transducers disposed on at least one surface of said substrate for generating elastic waves; means for exciting electromagnetic fields through said substrate; and means for fixing a charge pattern within said substrate; said method comprising the steps of: generating a plurality of elastic waves respectively by said plurality of transducers, corresponding to said plurality of independent signals to be memorized; producing a first set of interactions between said elastic waves generated by said transducers when receiving said electrical signals to be memorized, termed the first signals, and a first electromagnetic field corresponding to a second electrical signal, said first interactions generating a time independent spatial charge pattern in said substrate, representing said first signals, said pattern being fixed by said means for fixing a charge pattern; and producing a second set of interactions between said fixed pattern and a second electromagnetic field corresponding to a third electrical signal, said second interactions generating a second elastic wave, termed the reading wave, having the same characteristics as said first elastic wave, but propagating in the opposite direction thereof towards transducers from which they were originally generated.
Claim 27
Independent Claim
216 words
A method of memorizing a plurality of independent signals by means of an acoustic wave device, said device being of a type that includes: a piezo-electric substrate; a plurality of independent electromechanical transducers disposed on at least one surface of said substrate for generating elastic waves; means for exciting electromagnetic fields through said substrate; and means for fixing a charge pattern within said substrate; said method comprising the steps of: generating a plurality of elastic waves respectively by said plurality of transducers, corresponding to said plurality of independent signals to be memorized; producing a first set of interactions between said elastic waves generated by said transducers when receiving said electrical signals to be memorized, termed the first signals, and a first electromagnetic field corresponding to a second electrical signal, said first interactions generating a time independent spatial charge pattern in said substrate, representing said first signals, said pattern being fixed by said means for fixing a charge pattern; and producing a second set of interactions between said fixed pattern and a second electromagnetic field corresponding to a third electrical signal, said second interactions generating a second elastic wave, termed the reading wave, having the same characteristics as said first elastic wave, but propagating in the opposite direction thereof towards transducers from which they were originally generated.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-06-25 | 1982-12-25 | 1983-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-06-25 | 1986-12-25 | 1987-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-06-25 | 1990-12-25 | 1991-06-26 | $7700.00 | Window Closed / Lapsed |