US3768032A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acoustic surface wave devices
Assignee: US Philips Corp
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Filing: 1972-05-19
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Granted: 1973-10-23
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Expires: 1992-05-19
Abstract
Abstract An acoustic surface wave device having a low capacitance transducer array comprising a pair of parallel strip terminal electrodes at each end and a plurality of electrically isolated intermediate electrodes regularly spaced between them. Each intermediate electrode is shown either as a wide strip or preferably as a pair of narrower spaced parallel strips electrically connected together. Since the piezoelectric effect is determined by the induced electrical charge, which is the same for each electrode, a form of weighting is disclosed in which the length of the electrodes varies inversely with source strength, and only that part of the acoustic surface wave beam whose width corresponds to the shortest electrode is employed.
Inventors
- 👤 R Mitchell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:46
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/125; H03H9/145; H03H9/14544; H03H9/14517; H03H9/1452
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
125 words
An acoustic surface wave device comprising a body of piezoelectric material, and an acoustic surface wave transducer arranged on an acoustic surface wave propagation surface of said body, said acoustic surface wave transducer comprising a pair of parallel elongate spaced apart terminal electrodes and a plurality of substantially parallel adjacent elongate conductive electrodes conductively separate one from the other and arranged in succession between said elongate terminal electrodes and substantially parallel thereto so that an electrical signal of a predetermined frequency applied to said terminal electrodes will launch a surface elastic wave to propagate over said surface and that an acoustic surface wave propagating over said surface will be detected by said electrodes to cause a corresponding electric signal to occur at said terminal electrodes.
Claim 2
Dependent Claim
125 words
An acoustic surface wave device comprising a body of piezoelectric material, and an acoustic surface wave transducer arranged on an acoustic surface wave propagation surface of said body, said acoustic surface wave transducer comprising a pair of parallel elongate spaced apart terminal electrodes and a plurality of substantially parallel adjacent elongate conductive electrodes conductively separate one from the other and arranged in succession between said elongate terminal electrodes and substantially parallel thereto so that an electrical signal of a predetermined frequency applied to said terminal electrodes will launch a surface elastic wave to propagate over said surface and that an acoustic surface wave propagating over said surface will be detected by said electrodes to cause a corresponding electric signal to occur at said terminal electrodes.
Claim 3
Dependent Claim
30 words
An acoustic surface wave device as claimed in claim 1 in which each of the conductively separate elongate electrodes comprises a pair of spaced parallel conductive strips conductively joined together.
Claim 4
Dependent Claim
21 words
An acoustic surface wave device as claimed in claim 2 in which said acoustic surface wave transducer is a launching transducer.
Claim 5
Dependent Claim
43 words
An acoustic surface wave device as claimed in claim 2 in which the piezoelectric material has the property that the generation of acoustic surface waves by an interdigital launching electrode is determined by the electrical charge induced on the surface of said body.
Claim 6
Dependent Claim
19 words
An acoustic surface wave device as claimed in claim 3 in which the piezoelectric material comprises a ferroelectric ceramic.
Claim 7
Dependent Claim
103 words
An acoustic surface wave device as claimed in claim 3 in which a weighted distribution of effective acoustic surface wave source strength is provided along said launching transducer by arranging the lengths of said elongate electrodes in inverse relationship with the desired effective source strength, and a receiving transducer arranged on said propagation sUrface and in the path of a beam of acoustic surface waves propagated from said launching transducer so that the portion of said receiving transducer responsive to acoustic surface waves lies substantially entirely within that part of said beam which is formed by all the pairs of said elongate electrodes.
Claim 8
Dependent Claim
83 words
An ultrasonic device comprising a body of piezoelectric material, and a pair of acoustic surface wave transducers spaced apart on a surface of said body for transmitting and receiving, respectively, an acoustic surface wave propagated contiguous to said surface, at least one of said transducers comprising a pair of spaced apart parallel elongate conductive terminal electrodes and a plurality of parallel elongate conductive electrodes insulatively separated from each other and from the terminal electrodes and arranged between said terminal electrodes and parallel thereto.
Claim 9
Dependent Claim
83 words
An ultrasonic device comprising a body of piezoelectric material, and a pair of acoustic surface wave transducers spaced apart on a surface of said body for transmitting and receiving, respectively, an acoustic surface wave propagated contiguous to said surface, at least one of said transducers comprising a pair of spaced apart parallel elongate conductive terminal electrodes and a plurality of parallel elongate conductive electrodes insulatively separated from each other and from the terminal electrodes and arranged between said terminal electrodes and parallel thereto.
Claim 10
Dependent Claim
32 words
An ultrasonic device as claimed in claim 7 wherein said plurality of elongate electrodes each comprise a pair of spaced parallel conductive members joined together at one end by a conductive member.
Claim 11
Dependent Claim
43 words
An ultrasonic device as claimed in claim 8 wherein said one transducer is adapted to receive an alternating electric signal of a given frequency at said terminal electrodes thereby to launch within said body an acoustic surface wave to propagate along said surface.
Claim 12
Dependent Claim
47 words
An ultrasonic device as claimed in claim 8 wherein said one transducer is adapted to detect an acoustic surface wave propagating in said body along said surface to derive an alternating electric signal at said terminal electrodes corresponding to an electric signal applied to the transmitting transducer.
Claim 13
Dependent Claim
22 words
An ultrasonic device as claimed in claim 9 wherein said plurality of elongate electrodes vary progressively in length between said terminal electrodes.
Claim 14
Dependent Claim
31 words
An ultrasonic deivce as claimed in claim 9 wherein said plurality of elongate electrodes vary progressively in length from the mid-point between said terminal electrodes to each of the terminal electrodes.
Claim 15
Dependent Claim
22 words
An ultrasonic device as claimed in claim 10 wherein said plurality of elongate electrodes vary progressively in length between said terminal electrodes.
References Cited (Backward Citations)
US3289114A
Cited
US3696312A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |