PURPOSE: To enhance the sensitivity of the title sensor, by providing a circular hole to the center part of a piezoelectric element and fixing an annular mass adding layer to said element along the circumference of the circular hole and increasing the inertial mass of the piezoelectric element.
CONSTITUTION: The detection part 2 of the title sensor is constituted by fitting a piezoelectric element 7, which is formed from a vibration plate 4 formed into a disc shape and having a circular hole 3 provided to the center thereof, the piezoelectric layer 5 integrally fixed to the plate 4 and the annular mass adding layer 6 provided on the layer 5 along the circumference of the hole 3, to an annular fixing frame 8. Since the hole 3 is provided to the center part of the element 7, the quantity of electricity emitted from the element is made constant and strong and, since the inertial mass of the element 7 is increased, strain is made easy to generate by weak force. Therefore, acceleration can be measured with high sensitivity.
KUNIMURA SATOSHI
TAKAHASHI KATSUHIKO
