US3893047A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acoustic surface wave transmission system
Assignee: Thales SA
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Filing: 1974-03-04
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Granted: 1975-07-01
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Expires: 1994-03-04
Abstract
Abstract A system for processing a signal during its transmission in the form of acoustic surface waves. A piezoelectric substrate, having transmitting and receiving transducers and at least one grating reflecting transmitted acoustic surface waves, comprises a thin photoconductive layer on the path of the reflected waves. Subjecting the layer-substrate interaction zone to selective illumination of variable intensity leads to the production of an acousto-electric effect having zero electric field, so that the signal is attenuated outside the nonilluminated zones. The invention is of use particularly for non-dispersive filters and light-controlled delay lines.
Inventors
- 👤 Claude Lardat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:15
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/30; H03H9/42; H03H9/44; H03H9/02; H03H9/02535; H03H9/02637; H03H9/02685; H03H9/02716; H03H9/02779; H03H9/02795; H03H9/0296; H03H9/02968; H03H9/423; H03H9/70; H03H9/72
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
169 words
Acoustic surface wave transmission device using means cooperating in a combination comprising: a piezoelectric substrate having on one face transducers between which the acoustic surface waves propagate; at least one transmitting electro-acoustic transducer connected to an electric signal source and producing the transmitted acoustic waves; at least one acousto-electric transducer receiving the waves and outputting to a load; at least one reflective grating constituted by a series of discontinuities parallel to one another at an inclination to wave propagation direction redirecting the transmitted wave; characterised in that the device also comprises at least one thin photoconductive layer (5) disposed on the substrate (1) between the grating (3) and the receiving transducer (4), a light source (6) to cause illumination of said layer so as to make use of the zeroelectric-field acousto-electric effect arising from interaction between the layer when illuminated and the acoustic surface wave, and means to allow said zero effect to take place only at given regions of said substrate between said grating and said receiving transducer.
Claim 2
Dependent Claim
169 words
Acoustic surface wave transmission device using means cooperating in a combination comprising: a piezoelectric substrate having on one face transducers between which the acoustic surface waves propagate; at least one transmitting electro-acoustic transducer connected to an electric signal source and producing the transmitted acoustic waves; at least one acousto-electric transducer receiving the waves and outputting to a load; at least one reflective grating constituted by a series of discontinuities parallel to one another at an inclination to wave propagation direction redirecting the transmitted wave; characterised in that the device also comprises at least one thin photoconductive layer (5) disposed on the substrate (1) between the grating (3) and the receiving transducer (4), a light source (6) to cause illumination of said layer so as to make use of the zeroelectric-field acousto-electric effect arising from interaction between the layer when illuminated and the acoustic surface wave, and means to allow said zero effect to take place only at given regions of said substrate between said grating and said receiving transducer.
Claim 3
Dependent Claim
63 words
A device according to claim 1, characterised in that it comprises two identical parallel gratings (31, 32) with the discontinuities spaced apart at a predetermined increasing pitch, the thin layer (5) being disposed between the gratings, the resulting interaction zone having a particular length in the transmitted wave propagation direction, said layer not being illuminated over at least a part of said length.
Claim 4
Dependent Claim
57 words
A device according to claim 2, characterised in that it comprises a moving mask (7) having at least one opaque zone (70) disposed opposite the thin layer (5), the opacity, the area and the shape of said zone and the position thereof relatively to the grating determining the operating characteristics of the resulting non-dispersive band pass filter.
Claim 5
Dependent Claim
28 words
A device according to claim 3, characterised in that the opaque zone (70) has a particular shape such that the frequency band of the non-despersive filter is weighted.
Claim 6
Dependent Claim
26 words
A device according to claim 3, characterised in that the mask (7) has a number of different opaque zones (70) to provide an interdigital non-dispersive filter.
Claim 7
Dependent Claim
38 words
A device according to claim 1, characterised in that the thin layer (5) is distributed over the substrate (1) in a number of different portions (51 to 5n) having a predetermined spacing, to provide a non-dispersive interdigital filter.
Claim 8
Dependent Claim
32 words
A device according to claim 6, characterised in that the thin layer (5) extends over areas having a particular shape corresponding to a predetermined weighting of the frequency band of the device.
Claim 9
Dependent Claim
44 words
A device according to claim 1, characterised in that it comprises two identical parallel gratings (31, 32) with a constant spacing between the discontinuities, the thin layer (5) being disposed between the two gratings and being selectively removed from illumination by an opaque mask.
Claim 10
Dependent Claim
27 words
A device according to claim 8, characterised in that the mask comprises a number of opaque zones and its position is fixed, to provide an amplitude-coded line.
Claim 11
Dependent Claim
28 words
A device according to claim 8, characterised in that said mask is a moving mask whose position determines the delay time of the non-dispersive delay line tHus devised.
Claim 12
Dependent Claim
126 words
A device according to claim 1, characterised in that it comprises, on said substrate (1), a single transmitting transducer (2), a constant-pitch reflective grating (3) to redirect the transmitted wave, a series of receiving transducers (41 to 4n) and a thin layer (5) disposed on the substrate (1) between the grating (3) and the receiving transducers (41 to 4n), which transducers are positioned in an alignment dependency with regard to said layer, and an opaque moving mask disposed opposite a part of the thin layer (5) whose position is adjustable so as to allow the redirected wave to propagate towards one of said receiving transducers, the device thus providing a tapped line whose switching is programmable by alteration of mask position relatively to the layer (5).
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) | 1978-06-30 | 1978-12-30 | 1979-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-30 | 1982-12-30 | 1983-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-30 | 1986-12-30 | 1987-07-01 | $7700.00 | Window Closed / Lapsed |