Piezoelectric sensor

Abstract

This piezoelectric sensor has: a piezoelectric sheet; a first ground electrode integrally laminated upon a first surface of the piezoelectric sheet and having a first cut-out section; a signal electrode integrally laminated upon a second surface of the piezoelectric sheet and having a third cut-out section; and a second ground electrode integrally laminated upon the signal electrode, in a state electrically insulated from the signal electrode, and having a second cut-out piece. The cut-out sections of the signal electrode, the first ground electrode, and the second ground electrode are at least partially overlapping in the thickness direction of the piezoelectric sheet. The section of the piezoelectric sheet exposed from the cut-out sections of the first ground electrode, the second ground electrode, and the signal electrode that overlap in the thickness direction of the piezoelectric sheet serves as an exposed section.

Description

technical field [0001] The present invention relates to a piezoelectric sensor capable of maintaining excellent piezoelectricity over a long period of time Background technique [0002] A biosignal sensor using a piezoelectric sheet as a sensor is known. When the pressure generated by pulse wave, respiration, and physical activity is applied to the piezoelectric sheet, an electrical signal corresponding to the pressure will be generated by the piezoelectric sheet, and the biological signal can be detected by using the electrical signal. [0003] Patent Document 1 discloses a piezoelectric sensor that includes a piezoelectric body made of a polymer material, a first electrode bearing portion that is placed on one side of the piezoelectric body and that carries a signal electrode on a first insulator, and that is placed on a first insulator. The other side of the piezoelectric body and the second electrode bearing portion that supports the ground electrode on the second insul...

AI Technical Summary

Problems solved by technology

Once the solvent or residual monomer penetrates into the piezoelectric sheet, the piezoelectric sheet constituting the piezoelectric sensor of Patent Document 1 is sealed by the fixing agent as described above, and the solvent or residual monomer that has penetrated into the piezoelectric sheet cannot be released. Diffusion and removal of residual monomers to the outside of the piezoelectric sheet results in a decrease in the piezoelectricity of the piezoelectric sheet

[0008] In addition, as the adhesive constituting the fixing agent, acrylic adhesives are often used. Since acrylic adhesives are polar, acrylic adhesives tend to contain water vapor, and water vapor may pass through the fixing agent. In this case, the water vapor permeated into the piezoelectric sheet cannot be diffused and removed outside the piezoelectric sheet, and the piezoelectricity of the piezoelectric sheet will decrease.

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