EP0174897A2
Expired / Lapsed
EP
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Underwater piezoelectric arrangement
Assignee: Niterra Co Ltd
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Filing: 1985-09-11
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Granted: —
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Expires: 2005-09-11
Abstract
Abstract Underwater piezoelectric arrangement in which it comprises two piezoelectric layers (12, 14) made of piezoelectric ceramic-polymer composites, one of the layers (14) has larger hydrophone constant than that of the other layer (12), and by noise cancelling based on the specific construction of the piezoelectric layers only charges or voltages generated by acoustic waves which act on each layer can be selectively detected. The piezoelectric arrangement may be utilized to provide a piezoelectric cable for use in a submarine earthquake searching or fish finding hydrophone, or an acoustic measuring element under water.
Inventors
- 👤 Hisao Banno
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 09:19
CPC Classifications
G; G01; G01V; G01V1/00; G01V1/16; G01V1/20; G01V1/201; G01V1/208; H; H04; H04R; H04R17/00; H04R17/005; H10; H10N; H10N30/00; H10N30/60; Y; Y10; Y10S; Y10S310/00; Y10S310/80
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
95 words
An underwater piezoelectric arrangement comprising a first and second piezoelectric layers made of piezoelectric ceramic-polymer composites said first and second piezoelectric layers being so arranged that one of the layers has larger hydrophone constant than that of the other layer and the charge or voltage generated by a stress which acts on said one layer in a direction parallel to the surface thereof is substantially equal to that of the other layer, and mean for producing a difference in charges or voltages generated by acoustic waves which act on said first and second piezoelectric layers.
Claim 2
Dependent Claim
95 words
An underwater piezoelectric arrangement comprising a first and second piezoelectric layers made of piezoelectric ceramic-polymer composites said first and second piezoelectric layers being so arranged that one of the layers has larger hydrophone constant than that of the other layer and the charge or voltage generated by a stress which acts on said one layer in a direction parallel to the surface thereof is substantially equal to that of the other layer, and mean for producing a difference in charges or voltages generated by acoustic waves which act on said first and second piezoelectric layers.
Claim 3
Dependent Claim
28 words
An underwater piezoelectric arrangement as claimed in claim 1, wherein the polarizing direction of said first piezoelectric layer is the same as that of said second piezoelectric layer.
Claim 4
Dependent Claim
27 words
An underwater piezoelectric arrangement as claimed in claim 1, wherein the polarizing direction of said first piezoelectric layer is opposite to that of said second piezoelectric layer.
Claim 5
Dependent Claim
60 words
An underwater piezoelectric arrangement as claimed in claim 1, wherein one of said first and second piezoelectric layers is formed of a mixture of lead titanate (PbTi0 3 ) and organic material such as rubber or resin, and the other piezoelectric layer is formed of a mixture of lead zirco-titanate (Pb(Zr Ti)03) and organic material such as rubber or resin.
Claim 6
Dependent Claim
28 words
An underwater piezoelectric arrangement as claimed in claim 1, wherein each of said first and second piezoelectric layers has an inner and outer surfaces provided with electrode members.
Claim 7
Dependent Claim
21 words
An underwater piezoelectric arrangement as claimed in claim 5, wherein each of said electrode members is electrically insulated from the others.
Claim 8
Dependent Claim
24 words
An underwater piezoelectric arrangement as claimed in claim 1, wherein each of said first and second piezoelectric layers is in the form of sheet.
Claim 9
Dependent Claim
97 words
An underwater piezoelectric cable comprising a first and second piezoelectric layers made of piezoelectric ceramic-polymer composites which are provided around a cable core, said first and second piezoelectric layers being so arranged that one of the layers has larger hydrophone constant than that of the other layer and the charge or voltage generated by a stress which acts on one layer in its longitudinal direction is substantially equal to that of the other layer, and means for producing a difference in charges or voltages generated by acoustic waves which act on said first and second piezoelectric layers.
Claim 10
Dependent Claim
97 words
An underwater piezoelectric cable comprising a first and second piezoelectric layers made of piezoelectric ceramic-polymer composites which are provided around a cable core, said first and second piezoelectric layers being so arranged that one of the layers has larger hydrophone constant than that of the other layer and the charge or voltage generated by a stress which acts on one layer in its longitudinal direction is substantially equal to that of the other layer, and means for producing a difference in charges or voltages generated by acoustic waves which act on said first and second piezoelectric layers.
Claim 11
Dependent Claim
26 words
An underwater piezoelectric cable as claimed in claim 8, wherein said first and second piezoelectric layers are annular and are coaxially disposed around the cable core.
Claim 12
Dependent Claim
17 words
An underwater piezoelectric cable as claimed in claim 8, wherein said cable core is a central electrode.
Claim 13
Dependent Claim
20 words
An underwater piezoelectric cable as claimed in claim 8, wherein said first and second piezoelectric layers have opposite polarizing directions.
Claim 14
Dependent Claim
20 words
An underwater piezoelectric cable as claimed in claim 8, wherein said first and second piezoelectric layers have same polarizing direction.
Claim 15
Dependent Claim
30 words
An underwater piezoelectric cable as claimed in claim 8, wherein at least the outer surface of each of said first and second piezoelectric layers is provided with an electrode member.
Claim 16
Dependent Claim
24 words
An underwater piezoelectric cable as claimed in claim 8 or 9, wherein an insulator layer is interposed between said first and second piezoelectric layers.
References Cited (Backward Citations)
No citation records indexed.
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