Physical quantity sensor
AssigneePanasonic Corporation
InventorsTsutomu Nakanishi, Yasunobu Kobayashi, Koumel Hujita
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Abstract
A physical quantity sensor includes a beam-like vibrating body and a fixing part supporting both ends of the beam-like vibrating body. A driving element is formed on a central portion of the beam-like vibrating body, and feedback elements are formed on both ends. A physical quantity acting on the beam-like vibrating body is detected by causing natural vibration in the beam-like vibrating body and detecting a natural frequency of the vibrating body. This enables reliable detection of a physical quantity, such as a strain or load, acting on an object.
Claims7
A physical quantity sensor comprising:
- a beam-like vibrating body;
- a fixing part supporting both ends of the vibrating body;
- a first piezoelectric element formed on a central portion of the vibrating body;
- a second piezoelectric element formed on one end of the vibrating body;
- and
- a third piezoelectric element formed on an other end of the vibrating body,
- wherein
- the first piezoelectric element acts as a driving element;
- the second piezoelectric element and the third piezoelectric element act as feedback elements;
- and
- a physical quantity acting on the vibrating body is detected by causing natural vibration in the vibrating body and measuring a natural frequency of the vibrating body.
A physical quantity sensor comprising:
- a beam-like vibrating body;
- a fixing part supporting both ends of the vibrating body;
- a first piezoelectric element formed on a central portion of the vibrating body;
- a second piezoelectric element formed on one end of the vibrating body;
- and
- a third piezoelectric element formed on an other end of the vibrating body,
- wherein
- the first piezoelectric element acts as a feedback element;
- the second piezoelectric element and the third piezoelectric element act as driving elements;
- and
- a physical quantity acting on the vibrating body is detected by:
- causing natural vibration in the vibrating body by driving the second piezoelectric element and the third piezoelectric element with a same amplitude in a same phase;
- and
- measuring a natural frequency of the vibrating body.
A physical quantity sensor comprising:
- a beam-like vibrating body;
- a fixing part supporting both ends of the vibrating body;
- a first piezoelectric element formed on a central portion of the vibrating body;
- a second piezoelectric element formed on one end of the vibrating body;
- a third piezoelectric element formed on an other end of the vibrating body;
- a fourth piezoelectric element formed near the second piezoelectric element;
- and
- a fifth piezoelectric element formed near the third piezoelectric element,
- wherein
- the first piezoelectric element acts as a detecting element;
- the second piezoelectric element and the third piezoelectric element act as driving elements;
- the fourth piezoelectric element and the fifth piezoelectric element act as feedback elements;
- and
- a physical quantity acting on the vibrating body is detected by:
- causing natural vibration in the vibrating body by driving the second piezoelectric element and the third piezoelectric element with a same amplitude in a same phase;
- feeding back a vibration state by the fourth piezoelectric element and the fifth piezoelectric element;
- and
- detecting a natural frequency of the vibrating body by the first piezoelectric element.
Dependencies are inferred from the claim text.