Piezoelectric bimorph type acceleration sensor
First Claim
1. An acceleration sensor comprising:
- first and second piezoelectric ceramic plates each having first and second major surfaces;
a first signal electrode being formed on said first major surface of said first piezoelectric ceramic plate;
a second signal electrode being formed on said first major surface of said second piezoelectric ceramic plate; and
an intermediate electrode being arranged between said second major surfaces of said first and second piezoelectric ceramic plates,said first and second piezoelectric ceramic plates being bonded to each other with said intermediate electrode located therebetween so as to form a sensor body,said sensor body being mechanically held at locations along said sensor body close to both ends of said sensor body,said sensor body having first, second and third regions located along a length of said sensor body and formed so that stress is caused in different directions in adjacent regions of said first, second and third regions upon an acceleration force acting on said sensor body,said first and second piezoelectric ceramic plates being polarized in opposite directions in said second region, said second region being located at a center of said sensor body,said acceleration sensor further comprising means for preventing first charges which are opposite in polarity to second charges generated in said second region from being drawn from said signal electrodes in said first and third regions of said sensor body, wherein said first and second charges are generated by acceleration acting on said sensor body.
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Abstract
An acceleration sensor includes a sensor body obtained by forming first and second signal electrodes on outer major surfaces of first and second piezoelectric ceramic plates which are pasted to each other through an intermediate electrode. The sensor body is formed to be mechanically supported in the form of a center beam, and has first to third regions formed so that stress is caused in different directions in adjacent ones of the first to third regions upon acceleration. The first and second piezoelectric ceramic plates are polarized in opposite directions in the second region so that charges which are opposite in polarity to charges generated in the second region are not drawn from the signal electrodes in the first and third regions.
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Citations
23 Claims
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1. An acceleration sensor comprising:
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first and second piezoelectric ceramic plates each having first and second major surfaces; a first signal electrode being formed on said first major surface of said first piezoelectric ceramic plate; a second signal electrode being formed on said first major surface of said second piezoelectric ceramic plate; and an intermediate electrode being arranged between said second major surfaces of said first and second piezoelectric ceramic plates, said first and second piezoelectric ceramic plates being bonded to each other with said intermediate electrode located therebetween so as to form a sensor body, said sensor body being mechanically held at locations along said sensor body close to both ends of said sensor body, said sensor body having first, second and third regions located along a length of said sensor body and formed so that stress is caused in different directions in adjacent regions of said first, second and third regions upon an acceleration force acting on said sensor body, said first and second piezoelectric ceramic plates being polarized in opposite directions in said second region, said second region being located at a center of said sensor body, said acceleration sensor further comprising means for preventing first charges which are opposite in polarity to second charges generated in said second region from being drawn from said signal electrodes in said first and third regions of said sensor body, wherein said first and second charges are generated by acceleration acting on said sensor body. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An acceleration sensor comprising:
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first and second piezoelectric ceramic plates each having first and second major surfaces; a first signal electrode being formed on said first major surface of said first piezoelectric ceramic plate; a second signal electrode being formed on said first major surface of said second piezoelectric ceramic plate; and an intermediate electrode being arranged between said second major surfaces of said first and second piezoelectric ceramic plates, said first and second piezoelectric ceramic plates being bonded to each other with said intermediate electrode located therebetween so as to form a sensor body, said sensor body having first, second and third regions located along a length of said sensor body and formed so that stress is caused in different directions in adjacent regions of said first, second and third regions upon an acceleration force acting on said sensor body;
whereinsaid sensor body is formed so that first charges which are opposite in polarity to second charges generated in said second region are not drawn from said signal electrodes in said first and third regions of said sensor body, wherein said first and second charges are generated by acceleration acting on said sensor body. - View Dependent Claims (22, 23)
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Specification