Title:
EXTERNAL FORCE DETECTION APPARATUS
Document Type and Number:
Japanese Patent JP2015166679
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To accurately and easily detect an external force applied to a piezoelectric piece and to suppress influences of electrostatic charge charged in the piezoelectric piece.SOLUTION: A crystal piece 2 being a piezoelectric piece is cantilevered in the inside of a container 1. A tip end part of the underside of the crystal piece 2 is provided with a movable electrode 21, and a fixed electrode 22 is provided at a position facing the movable electrode 21. The movable electrode 21 and the fixed electrode 22 are connected to an oscillation circuit 41, and detects as a change in a frequency, a change in capacitance between the movable electrode 21 and the fixed electrode 22 due to warp caused by external force given to the crystal piece 2. Each of the container 1 and the crystal piece 2 is composed of a crystal having a volume resistivity lower than that of an ordinary crystal, and the movement of the electric charge is made easy. The container 1 is connected to the earth, and discharges an electrostatic charge accumulated in the crystal piece 2 by the influences of an electrostatic field and the like to the outside of a detector.
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Inventors:
HIROTA KAZUHIRO
KOYAMA MITSUAKI
MUTO TAKESHI
KOYAMA MITSUAKI
MUTO TAKESHI
Application Number:
JP2014040574A
Publication Date:
September 24, 2015
Filing Date:
March 03, 2014
Export Citation:
Assignee:
NIHON DEMPA KOGYO CO
International Classes:
G01P15/10; G01L1/10; G01L9/00; H03B5/32; H03H9/02; H03H9/19
Attorney, Agent or Firm:
Toshio Inoue
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