Load sensor with use of crystal resonator

Abstract

Excitation electrodes are respectively affixed to central portions of both surfaces of a long plate-shaped AT-cut crystal resonator, the central portion starts a thickness shear oscillation in the length direction of the crystal resonator when an electric signal is applied to the central portion of the crystal resonator through the excitation electrodes. And, channel-shaped, half-circular-shaped, or trapezoid grooves in cross-section are respectively formed in the plate width direction on middle portions between the center portion and end portions of the crystal resonator. These grooves are formed so as to be symmetrical with respect to a thicknesswise central position of the crystal resonator through a well-known etching technique such as photo-etching and the like.

1 . A load sensor with use of a crystal resonator comprising: 
 a flat plate-shaped crystal resonator for oscillating in a thickness shear oscillation mode; and    supporting bodies for supporting the crystal resonator;    wherein the crystal resonator is retained between the supporting bodies which are respectively in contact with and pressing opposing end faces of the crystal resonator in a direction of a thickness shear oscillation of he outside of the crystal resonator;    wherein the end faces are configured to minimize the areas contacting the supporting bodies as much as possible, such that the supporting bodies contact the end faces along less than an entire thickness of the end faces; and    wherein a load is measured based on change in an oscillation frequency of the thickness shear oscillation of the crystal resonator generated in proportion to the load acted thereon through the supporting bodies.    
   
   
       2 . The load sensor with use of a crystal resonator according to  claim 1 , wherein the end faces are circular-arc-shaped, being curved in a thickness direction of the crystal resonator.