Piezoelectric element and device using same

Patent metadata

Field	Value
Publication number	US-10950779-B2
Application number	US-201615569878-A
Country	US
Kind code	B2
Filing date	Apr 28, 2016
Priority date	Apr 30, 2015
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

The purpose of the present invention is to provide a fibrous piezoelectric element which enables a large electric signal to be drawn out by stress produced by relatively small deformation. A piezoelectric element includes a braid composed of a conductive fiber and a piezoelectric fiber. In the braid, the conductive fiber is a core, and the piezoelectric fiber is a covering fiber that covers the periphery of the conductive fiber.

First claim

The invention claimed is:

1. A piezoelectric element including a braid comprising a conductive fiber, an insulating fiber and piezoelectric fibers, the braid having the conductive fiber as the core, and the insulating fiber and the piezoelectric fibers being covering fibers that cover the periphery of the conductive fiber, wherein the flexural rigidity of the conductive fiber is no greater than 0.05×10 −4 N·m 2 /m, wherein the piezoelectric fibers comprise polylactic acid.

2. The piezoelectric element according to claim 1 , wherein the conductive fiber is a metal coated organic fiber.

3. The piezoelectric element according to claim 1 , wherein the piezoelectric fibers comprise poly-L-lactic acid or poly-D-lactic acid with an optical purity of 99% or greater.

4. The piezoelectric element according to claim 1 , wherein the piezoelectric fibers are uniaxially oriented and include crystals.

5. The piezoelectric element according to claim 1 , which detects the amount of stress applied to the covering fibers and/or the location at which it is applied.

6. The piezoelectric element according to claim 5 , wherein the stress to be detected is frictional force between the surfaces of the covering fibers and the surface of the contacting object.

7. The piezoelectric element according to claim 5 , wherein the stress to be detected is resistance in the direction perpendicular to the surfaces or tip sections of the covering fibers.

8. A piezoelectric sensor using the piezoelectric element according to claim 1 .

9. A device comprising:
a piezoelectric sensor according to claim 8 ,
amplification means that amplifies an electrical signal outputted from the piezoelectric sensor in response to applied pressure, and
output means that outputs the electrical signal that has been amplified by the amplification means.

10. The device according to claim 9 , the device further comprising transmission means that transmits the electrical signal that has been outputted from the output means, to an external device.

11. A device comprising:
the piezoelectric sensor according to claim 8 ,
output means that outputs an electrical signal from the piezoelectric sensor in response to applied pressure, and
transmission means that transmits the electrical signal outputted from the output means, to an external device.

12. The piezoelectric element according to claim 1 , wherein the flexural rigidity of the conductive fiber is no greater than 0.02×10 −4 N·m 2 /m.

13. The piezoelectric element according to claim 1 , wherein the conductive fiber is carbon fiber.

Assignees

• Teijin Ltd
• Univ Kansai

Inventors

• Tajitsu Yoshiro
• Ono Yuhei
• Yamamoto Tomoyoshi
• Kanematsu Shunsuke
• Yoshizaki Satoko
• Ozawa Suguru

Classifications

• H10N30/702 Primary

  based on piezoelectric or electrostrictive fibres · CPC title

• D03D1/0088

  Fabrics having an electronic function · CPC title

• H10N30/60

  having a coaxial cable structure · CPC title

• H10N30/30

  with mechanical input and electrical output, e.g. functioning as generators or sensors · CPC title

• H10N30/098

  Forming organic materials · CPC title