GB1605040A - Transducers - Google Patents

Transducers Download PDF

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Publication number
GB1605040A
GB1605040A GB4402977A GB4402977A GB1605040A GB 1605040 A GB1605040 A GB 1605040A GB 4402977 A GB4402977 A GB 4402977A GB 4402977 A GB4402977 A GB 4402977A GB 1605040 A GB1605040 A GB 1605040A
Authority
GB
United Kingdom
Prior art keywords
piezoelectric
layer
plastics
layers
diaphragm
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB4402977A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Plessey Co Ltd
Original Assignee
Plessey Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to GB25370/74A priority Critical patent/GB1515287A/en
Application filed by Plessey Co Ltd filed Critical Plessey Co Ltd
Priority to GB4402977A priority patent/GB1605040A/en
Publication of GB1605040A publication Critical patent/GB1605040A/en
Application status is Expired legal-status Critical

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04RLOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R17/00Piezo-electric transducers; Electrostrictive transducers
    • H04R17/005Piezo-electric transducers; Electrostrictive transducers using a piezo-electric polymer
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04RLOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2499/00Aspects covered by H04R or H04S not otherwise provided for in their subgroups
    • H04R2499/10General applications
    • H04R2499/11Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's

Description

(54) IMPROVEMENTS IN OR RELATING TO TRANSDUCERS (71) We, THE PLESSEY COMPANY LIMITED, a British Company, of Vicarage Lane, Ilford, Essex, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to transducers, and more particularly to transducers for telephone subscriber's instruments, incorporating piezoelectric plastics elements.

Transducers incorporating piezoelectric plastics elements have been described in our British Patent No. 1,515,287 and it is an object of the present invention to provide an alternative form of piezoelectric transducer to those previously described.

According to the present invention there is provided a piezoelectric transducer for a telephone subscriber's instrument including a multi-layered diaphragm comprising first and second piezoelectric plastics layers, a layer of non-piezoelectric material, said layer of non-piezoelectric material being sandwiched between said first and second piezoelectric plastics layer, in which said first and second piezoelectric layers are provided with at least an electrode on their outer faces, and including support means for said multi-layered diaphragm to hold said diaphragm in an untensioned state, said diaphragm being substantially flat.

Preferably said layer of non-piezoelectric material may be of a plastics material.

Alternatively said layer may be a layer of fine powder.

Preferably the piezoelectric plastics layers are provided with electrodes on both surfaces. The electrodes are preferably vapour deposited on the surfaces.

Embodiments of the present invention will now be described, by way of example with reference to the drawing accompanying the provisional specification which shows a piezoelectric transducer according to the present invention.

The piezoelectric transducer shown comprises a multi-layered diaphragm constructed from first piezoelectric plastics layer 1 with electrodes 2, 3 provided on both major surfaces thereof. A second piezoelectric plastics layer 4 is similarly provided with electrodes 5, 6 on both of its major surfaces.

A layer 7 is sandwiched between electrodes 3 and 5 of piezoelectric layers 1 and 4 respectively. In a preferred embodiment the layer 7 is an inert plastics layer and is preferably between one fifth and twice the thickness of one of the piezoelectric layers.

The piezoelectric layers will normally be of the same thickness and an average value for their thickness will be 25 Fm. The electrodes are extremely thin and will not contribute substantially to the total thickness.

The separating layer 7 will normally be between 5 and 75 Fm thick.

In a second embodiment the separating layer is formed by introducing a fine powder with a carefully chosen granule size between the two electroded piezoelectric plastics layers.

The support means (not shown) for the multi-layered diaphragm structure described above may be as shown and described in the above patent.

WHAT WE CLAIM IS: 1. A piezoelectric transducer for a telephone subscriber's instrument including a multi-layered diaphragm comprising first and second piezoelectric plastics layers, a layer of non-piezoelectric material, said layer of non-piezoelectric material being sandwiched between said first and second piezoelectric plastics layer, in which said first and second piezoelectric layers are provided with at least an electrode on their outer faces, and including support means for said multi-layered diaphragm to hold said diaphragm in an untensioned state, said

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. (54) IMPROVEMENTS IN OR RELATING TO TRANSDUCERS (71) We, THE PLESSEY COMPANY LIMITED, a British Company, of Vicarage Lane, Ilford, Essex, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to transducers, and more particularly to transducers for telephone subscriber's instruments, incorporating piezoelectric plastics elements. Transducers incorporating piezoelectric plastics elements have been described in our British Patent No. 1,515,287 and it is an object of the present invention to provide an alternative form of piezoelectric transducer to those previously described. According to the present invention there is provided a piezoelectric transducer for a telephone subscriber's instrument including a multi-layered diaphragm comprising first and second piezoelectric plastics layers, a layer of non-piezoelectric material, said layer of non-piezoelectric material being sandwiched between said first and second piezoelectric plastics layer, in which said first and second piezoelectric layers are provided with at least an electrode on their outer faces, and including support means for said multi-layered diaphragm to hold said diaphragm in an untensioned state, said diaphragm being substantially flat. Preferably said layer of non-piezoelectric material may be of a plastics material. Alternatively said layer may be a layer of fine powder. Preferably the piezoelectric plastics layers are provided with electrodes on both surfaces. The electrodes are preferably vapour deposited on the surfaces. Embodiments of the present invention will now be described, by way of example with reference to the drawing accompanying the provisional specification which shows a piezoelectric transducer according to the present invention. The piezoelectric transducer shown comprises a multi-layered diaphragm constructed from first piezoelectric plastics layer 1 with electrodes 2, 3 provided on both major surfaces thereof. A second piezoelectric plastics layer 4 is similarly provided with electrodes 5, 6 on both of its major surfaces. A layer 7 is sandwiched between electrodes 3 and 5 of piezoelectric layers 1 and 4 respectively. In a preferred embodiment the layer 7 is an inert plastics layer and is preferably between one fifth and twice the thickness of one of the piezoelectric layers. The piezoelectric layers will normally be of the same thickness and an average value for their thickness will be 25 Fm. The electrodes are extremely thin and will not contribute substantially to the total thickness. The separating layer 7 will normally be between 5 and 75 Fm thick. In a second embodiment the separating layer is formed by introducing a fine powder with a carefully chosen granule size between the two electroded piezoelectric plastics layers. The support means (not shown) for the multi-layered diaphragm structure described above may be as shown and described in the above patent. WHAT WE CLAIM IS:
1. A piezoelectric transducer for a telephone subscriber's instrument including a multi-layered diaphragm comprising first and second piezoelectric plastics layers, a layer of non-piezoelectric material, said layer of non-piezoelectric material being sandwiched between said first and second piezoelectric plastics layer, in which said first and second piezoelectric layers are provided with at least an electrode on their outer faces, and including support means for said multi-layered diaphragm to hold said diaphragm in an untensioned state, said diaphragm being substantially flat.
2. A piezoelectric transducer as claimed in claim 1 in which said layer of nonpiezoelectric material is of a plastics material.
3. A piezoelectric transducer as claimed in claim 1 in which said layer of nonpiezoelectric material is a layer of fine powder.
4. A piezoelectric transducer for a telephone subscriber's instrument substantially as described with reference to the drawing accompanying the provisional specification.
GB4402977A 1974-05-30 1978-05-16 Transducers Expired GB1605040A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB25370/74A GB1515287A (en) 1974-05-30 1974-05-30 Piezoelectric transducers
GB4402977A GB1605040A (en) 1974-05-30 1978-05-16 Transducers

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB4402977A GB1605040A (en) 1974-05-30 1978-05-16 Transducers

Publications (1)

Publication Number Publication Date
GB1605040A true GB1605040A (en) 1981-12-16

Family

ID=26257644

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4402977A Expired GB1605040A (en) 1974-05-30 1978-05-16 Transducers

Country Status (1)

Country Link
GB (1) GB1605040A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2130844A (en) * 1982-11-19 1984-06-06 Thomson Csf Velocity hydrophone
EP1422970A2 (en) * 2002-10-21 2004-05-26 Sonitron, naamloze Vennootschap Transducer of the piezo-electric type

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2130844A (en) * 1982-11-19 1984-06-06 Thomson Csf Velocity hydrophone
EP1422970A2 (en) * 2002-10-21 2004-05-26 Sonitron, naamloze Vennootschap Transducer of the piezo-electric type
BE1015150A3 (en) * 2002-10-21 2004-10-05 Sonitron Nv Improved transducer
EP1422970A3 (en) * 2002-10-21 2005-07-20 Sonitron, naamloze Vennootschap Transducer of the piezo-electric type
US7596235B2 (en) 2002-10-21 2009-09-29 Sonitron, Naamloze Vennootschap Transducer

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee