Biological piezoelectric transducer device for the living body

• US 4,443,730 A
• Filed: 05/12/1982
• Issued: 04/17/1984
• Est. Priority Date: 11/15/1978
• Status: Expired due to Term

• Current Assignee: Mitsubishi Petrochemical Co., Ltd. (Mitsubishi Chemical Group Corp.)
• Original Assignee: Mitsubishi Petrochemical Co., Ltd. (Mitsubishi Chemical Group Corp.)
• Inventors: Kamimura, Kunio, Nakayama, Toshio, Kitamura, Mitsuaki, Seo, Iwao, Yaguchi, Tomonobu
• Primary Examiner(s): Budd, Mark O.
• Application Number:
  US06/377,388
• Time in Patent Office: 706 Days
• Field of Search: 310/330-332, 310/800, 310/323, 310/363-366, 310/324, 310/337, 310/340, 310/358
• US Class Current: 310/330
• CPC Class Codes: A61B 7/045 Detection of Korotkoff sounds A61B5/0225 takes precedence; measuring blood pressure A61B5/021
• CPC Class Codes: G01L 9/0001 Transmitting or indicating the displacement of elastically deformable gauges by electric, electro-mechanical, magnetic or electro-magnetic means G01L9/0026, G01L9/0033, G01L9/0082, G01L9/0089, G01L9/0091 take precedence
• CPC Class Codes: H10N 30/302 Sensors
• CPC Class Codes: Y10S 310/80 Piezoelectric polymers, e.g. PVDF

Abstract

A biological transducer device for measuring blood pressure, heart pulse, heart sound etc. comprising a high molecular piezoelectric element which is in a thin film or ribbon form so that the transducer is very pliable so as to make close accurate contact with a measuring point on a human body without producing any creases. The piezoelectric element is enclosed in netting comprised of a metal wire mesh so that the transducer is completely shielded from outer mechanical and electrical noise.

Claims

1. A biological transducer device comprising a flexible organic film like high molecular peizoelectric element having electrode layers secured to both surfaces of opposite sides;

a lead wire connected to each of said electrode layers;

thin film auxiliary electrodes connected to said lead wires extending along the electrode layers of said piezoelectric element, at least one of said auxiliary electrodes being secured to one electrode layer at one end with the other end being free to allow free to allow free displacement of said one auxiliary electrode;

an insulating film formed around the piezoelectric element;

shielding mens for shielding the piezoelectric element; and

a protective skin covering the exterior of said shielding means whereby the assembly is flexible.

2. A biological transducer device as claimed in claim 1, in which said piezoelectric element is a thin film and each lead wire is connected at a position near one end of said piezoelectric element.

3. A biological transducer device as claimed in claim 1, in which the piezoelectric element is a flexible thin film in the range of 2-20 mm width, 30-250 mm length and 0.01-1 mm thickness.

4. A biological transducer device as claimed in claim 1, in which said shielding means is a netting consisting of wire having a diameter of less than 55 spaced at a distance of less than 88, each wire extending at an angle of 45 degrees to the longitudinal direction of said piezoelectric element.

5. A biological transducer device as claimed in claim 1, in which said piezoelectric element comprises a pair of piezoelectric elements superimposed on each other, a lead wire positioned between said piezoelectric elements at a position near one end, the lead wire and piezoelectric elements being secured at said one end so that the other end of the piezoelectric elements are free so as to allow free displacement, The upper and lower faces of said superimosed pair of piezoelectric elements being connected electrically.

6. A biological transducer device as claimed in claim 5, includes an electrode plate between said piezoelectric elements;

said lead wire being connected to the electrode plate.

7. A biological transducer device as claimed in claim 5, including auxiliary electrodes provided above, below and between said piezoelectric elements;

said auxiliary electrodes being secured to each other at a position where said lead wires are connected.

8. A biological transducer device as claimed in claim 6, wherein said electrode plate is a continuous plate.

9. A biological transducer device as claimed in claim 1, in which said piezoelectric element is a flexible thin film consisting of a synthetic resin in the range of 10 to 90% by volume, and a ferroelectirc ceramic in the range of 90 to 10% volume.

10. A biological transducer as claimed in claim 9, in which said synthetic resin is a polyacetal resin.

11. A biological transducer device comprising;

a pair of flexible film like high molecular piezoelectric elements, electrode layers secured to opposite sides of each of said piezoelectric elements, said piezoelectric elements being superimposed on each other, a thin film auxiliary electrode interposed between said piezoelectric elements;

further thin film auxiliary electrodes extending along the electrode layers at the upper and lower faces of said superimposed piezoelectric elements, an electrode plate interposed between said piezoelectric elements;

a lead wire connected to said electrode plate at a position near one end of said piezoelectric elements, said interposed auxiliary electrode being secured to the adjacent electrode layers and said electrode plate at a position where said lead wire is connected;

said further auxiliary electrodes being connected at one end to the adjacent electrode layers to allow free displacement of said auxiliary electrodes;

an insulating film surrounding said piezoelectric elements and electrodes;

shielding means for shielding the piezoelectric elements; and

a flexible protective skin covering the exterior of said shielding means.

12. A biological transducer device comprising;

a thin film piezoelectric element;

electrode means secured to the respective surfaces of said piezoelectric element;

a thin film auxiliary electrode extending along each electrode means secured to the surfaces of said piezoelectric element;

t least one lead wire connected to each of said electrodes of said piezoelectric element;

said auxiliary electrodes being secured to said electrode means at one end with the other ends being free to allow free displacement of said auxiliary electrodes;

an insulating film surrounding said piezoelectric element and electrodes;

shield means substantially surrounding said piezoelectric element;

a flexible protective skin covering the exterior of said shield means;

said piezoelectric elements being comprised of high molecular piezoelectric material.

13. The biological transducer device according to claim 12, wherein said high molecular material is an organic material.

14. The biological transducer device according to claim 13, wherein said organic material is a natural high polymer from the group consisting of cellulose or protein.

15. The biological transducer device according to claim 13, wherein said organic material is poly-γ

-methyl-L-glutamate.

16. The biological transducer device according to claim 13, wherein said organic material is a synthetic organic polymer from the group consisting of polyvinyl fluoride, polyvinylidene fluoride, polyvinyl chloride, polyacrylonitrile or polycarbonate.

17. The biological transducer device according to claim 12, wherein said high molecular material is a composite mixture of a synthetic resin and a piezoelectric ceramic.

18. The biological transducer device according to claim 17, wherein said composite mixture is comprised of a ratio of 10 to 90% by volume of a synthetic resin mixed with 90 to 10% by volume of a piezoelectric ceramic.

19. The biological transducer device according to claim 18, wherein said piezoelectric ceramic is a ferroelectric ceramic.

20. The biological transducer device according to claim 19, wherein said ferroelectric ceramic is from the group consisting of BatiO₃, or PbTiO₃ -PbZrO₃.

21. The biological transducer device according to claim 18, wherein said synthetic resin is from the group consisting of polyamide, polyvinylidene fluoride, or polyacetal resin.

22. The biological transducer device according to clim 18, wherein said ceramic is a ceramic powder having a fineness in the range of 0.2 to 44 microns.

23. The biological transducer device according to claim 22, wherein said ceramic powder has a fineness between 1 to 5 microns.