Piezoelectric/electrostrictive device

• US 7,321,180 B2
• Filed: 10/06/2004
• Issued: 01/22/2008
• Est. Priority Date: 10/01/1999
• Status: Expired due to Fees

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Ikeda, Koji, Kimura, Koji, Takeuchi, Yukihisa, Nanataki, Tsutomu, Shibata, Kazuyoshi
• Primary Examiner(s): Zarroli; Michael C.
• Application Number:
  US10/959,420
• Publication Number:
  US 20050168109A1
• Time in Patent Office: 1,203 Days
• Field of Search: 310/328, 310/320, 310/321, 310/330, 310/331
• US Class Current: 310/320
• CPC Class Codes: H10N 30/053 by integrally sintering piezoelectric or electrostrictive bodies and electrodes
• CPC Class Codes: H10N 30/2042 Cantilevers, i.e. having one fixed end
• CPC Class Codes: H10N 30/2043 connected at their free ends, e.g. parallelogram type
• CPC Class Codes: H10N 30/302 Sensors
• CPC Class Codes: H10N 30/501 having a non-rectangular cross-section in a plane parallel to the stacking direction, e.g. polygonal or trapezoidal in side view

Abstract

A piezoelectric/electrostrictive device is provided, including a pair of mutually opposing thin plate sections and a fixation section for supporting the thin plate sections. A piezoelectric/electrostrictive element is arranged on each of the thin plate sections. The piezoelectric/electrostrictive device also includes movable sections defined by at least first end portions of the thin plate sections and a material which is different from that of the thin plate section.

Claims

1. A piezoelectric/electrostrictive device comprising:

a pair of mutually opposing thin plate sections;

a fixation section for supporting said thin plate sections;

movable sections comprising at least first end portions of said pair of thin plate sections; and

one or more piezoelectric/electrostrictive elements arranged on at least one thin plate section of said pair of thin plate sections;

wherein said movable sections further comprise another material which is different from the material of said thin plate sections.

2. The piezoelectric/electrostrictive device according to claim 1, wherein said another material comprises an adhesive member provided between said first end portions of said pair of thin plate sections.

3. The piezoelectric/electrostrictive device according to claim 1, wherein said movable sections include mutually opposing surfaces.

4. The piezoelectric/electrostrictive device according to claim 3, wherein a gap is formed between said mutually opposing surfaces of said movable sections.

5. The piezoelectric/electrostrictive device according to claim 1, wherein said first end portions of said pair of thin plate sections have mutually opposing end surfaces;

and

wherein a distance (Lc) between said mutually opposing end surfaces of said first end portions is not less than a length (Df) of said movable sections.

6. The piezoelectric/electrostrictive device according to claim 1, wherein said thin plate sections and said fixation section comprise an integrated, co-fired ceramic substrate formed from a ceramic green laminate from which unnecessary portions are removed.

7. The piezoelectric/electrostrictive device according to claim 6, wherein said piezoelectric/electrostrictive element has a film-shaped configuration, and wherein said piezoelectric/electrostrictive element is sintered with, and thereby integrated with, said ceramic substrate.

8. The piezoelectric/electrostrictive device according to claim 5, wherein a gap is present between said mutually opposing end surfaces of said first end portions of said pair of thin plate sections.

9. The piezoelectric/electrostrictive device according to claim 4, further comprising a member having substantially the same composition as a constitutive member of said movable sections, or a plurality of members which are compositionally different therefrom, interposed between said mutually opposing end surfaces of said movable sections, and an area of a surface of said member opposed to said mutually opposing end surfaces is substantially the same as an area of said mutually opposing end surfaces.

10. The piezoelectric/electrostrictive device according to claim 5, wherein said device has such a structure that internal residual stress, which has been generated in at least one of said thin plate sections and said piezoelectric/electrostrictive element during production, is released by forming said mutually opposing end surfaces of said first end portions of said thin plate sections.

11. The piezoelectric/electrostrictive device according to claim 1, wherein said piezoelectric/electrostrictive element comprises a piezoelectric/electrostrictive layer and a pair of electrodes formed on said piezoelectric/electrostrictive layer.

12. The piezoelectric/electrostrictive device according to claim 11, wherein said piezoelectric/electrostrictive element comprises a stacked structure comprising a plurality of units each including said piezoelectric/electrostrictive layer and said pair of electrodes.

13. A piezoelectric/electrostrictive device according to claim 9, further comprising a hole defined by both inner walls of said pair of thin plate sections, inner walls of said movable sections, inner walls of said plurality of members and an inner wall of said fixation section, wherein said hole is filled with a gel material.

14. A piezoelectric/electrostrictive device according to claim 1, wherein said thin plate sections and said fixation section comprise the same material.