Transducer
First Claim
1. A method comprising the step of sensing pressure produced thermal changes in a material having both pyroelectric and piezoelectric characteristics to detect such pressure, with an electrical signal produced having a first component produced as a result of the pyroelectric characteristic of the material which predominates over a second component of the signal produced as a result of the piezoelectric characteristic of the material.
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Accused Products
Abstract
A transducer having an energy conversion medium for converting changes in applied mechanical energy into corresponding changes in thermal energy and a pyroelectric material in thermal energy transfer relationship with the energy conversion medium for producing an electrical output substantially in response to the converted thermal energy. Such transducer is particularly useful as a hydrophone in detecting low frequency sound waves emitted by, or reflected from, underwater objects.
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Citations
49 Claims
- 1. A method comprising the step of sensing pressure produced thermal changes in a material having both pyroelectric and piezoelectric characteristics to detect such pressure, with an electrical signal produced having a first component produced as a result of the pyroelectric characteristic of the material which predominates over a second component of the signal produced as a result of the piezoelectric characteristic of the material.
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5. A transducer comprising:
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(a) means for converting mechanical energy into thermal energy; and (b) means, including a pyroelectric material disposed in thermal energy transfer relationship with the energy converting means, for producing an electrical output predominately in response to the converted thermal energy. - View Dependent Claims (6, 7, 8, 9, 10)
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11. A transducer for producing an electrical signal in response to impinging sound waves comprising:
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(a) means, including a medium which compresses and rarefies in response to compression and rarefication wavefronts of the sound waves, for correspondingly increasing and decreasing the thermal energy of the medium; and (b) a pyroelectric material in thermal conduction relationship with the medium to correspondingly increase and decrease the temperature of the material in response to the increase and decrease in the thermal energy of the medium, such pyroelectric material having the electrical charge distribution thereof change predominately in response to the temperature change of such material to produce the electrical signal in response to such electrical charge distribution changes. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A transducer disposed in a medium through which pressure waves are propagated, comprises
means including a pyroelectric material for producing an electrical output predominately in response to thermal energy applied thereto; - and
means, disposed between the means for producing the electrical output and the medium through which pressure waves are propagated, for converting the pressure waves propagating in said medium into thermal energy, with said converting means being disposed in thermal energy transfer relationship with the means for producing the electrical output. - View Dependent Claims (18, 19, 20, 21)
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22. A transducer for producing an electrical signal in response to impinging pressure waves, comprises:
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at least one chamber confining a compressible fluid, said chamber comprising; a flexible diaphragm provided to compress and rarefy the compressible fluid in response to the pressure waves and to increase and decrease, respectively, the thermal energy of the fluid; and a material having pyroelectric and piezoelectric characteristics disposed in thermal energy transfer relationship with the compressible fluid to correspondingly increase and decrease the temperature of the material in response to the increase and decrease of the thermal energy of the fluid, and to produce an electrical signal predominately as a result of the pyroelectric characteristic which predominates over a signal component produced as a result of the piezoelectric characteristic. - View Dependent Claims (23, 24, 25)
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26. A transducer comprising:
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a membrane comprising a polymer material having a piezoelectric characteristic and a pyroelectric characteristic; a flexible diaphragm; and a medium in thermal energy transfer relationship with the membrane which compresses and rarefies in response to compression and rarefication pressure fronts incident on the diaphragm to correspondingly increase and decrease the thermal energy of the medium and the membrane, and provide an electrical signal in accordance with the changes in thermal energy of the membrane predominately as a result of the pyroelectric characteristic of the membrane. - View Dependent Claims (27, 28, 29, 30, 31)
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32. A transducer, comprising:
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means responsive to applied mechanical energy for converting mechanical energy into thermal energy; and means, including a material having a pyroelectric characteristic and a piezoelectric characteristic disposed in thermal energy transfer relationship with the energy converting means, for producing an electrical output signal having two components, a pyroelectric component produced by the pyroelectric characteristic of the material in response to the converted thermal energy, and a piezoelectric component produced by the piezoelectric characteristic of the material in response to any of said mechanical energy which may produce a strain in said material with the pyroelectric component predominating over the piezoelectric component by at least an order of magnitude. - View Dependent Claims (33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49)
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Specification