Piezoelectric/electrostrictive device and method of manufacturing same

• US 20020101133A1
• Filed: 03/26/2002
• Published: 08/01/2002
• Est. Priority Date: 10/01/1999
• Status: Active Grant

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Nanataki, Tsutomu, Kimura, Koji, Takeuchi, Yukihisa, Namerikawa, Masahiko, Shibata, Kazuyoshi
• Granted Patent: US 6,796,011 B2
• Time in Patent Office: Days
• US Class Current: 310/321
• CPC Class Codes: H10N 30/053 by integrally sintering piezoelectric or electrostrictive bodies and electrodes
• CPC Class Codes: H10N 30/2043 connected at their free ends, e.g. parallelogram type
• CPC Class Codes: Y10T 29/42 Piezoelectric device making
• CPC Class Codes: Y10T 29/435 Solid dielectric type
• CPC Class Codes: Y10T 29/49078 Laminated
• CPC Class Codes: Y10T 29/49126 Assembling bases

Abstract

A piezoelectric/electrostrictive device comprises a pair of mutually opposing thin plate sections, a movable section, and a fixing section for supporting the thin plate sections and the movable section. Piezoelectric/electrostrictive elements are arranged on at least one thin plate section of the pair of thin plate sections. A hole is formed by both inner walls of the pair of thin plate sections, an inner wall of the movable section, and an inner wall of the fixing section. The piezoelectric/electrostrictive device has a mechanism for restricting amplitude of the thin plate sections. The mechanism comprises a cavity portion formed on the inner wall of the movable section and a stopper member provided on the inner wall of the fixing section, whose forward end enters the cavity portion.

Claims

1. A piezoelectric/electrostrictive device having a pair of mutually opposing thin plate sections, a movable section, and a fixing section for supporting said thin plate sections and said movable section, said piezoelectric/electrostrictive device comprising:

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

a hole formed by both inner walls of said pair of thin plate sections, an inner wall of said movable section, and an inner wall of said fixing section, wherein

a mechanism is provided for restricting amplitude of said thin plate sections.

2. A piezoelectric/electrostrictive device according to claim 1, said mechanism comprising:

a cavity portion formed on said inner wall of said movable section; and

a stopper member provided on said inner wall of said fixing section, whose forward end enters said cavity portion.

3. A piezoelectric/electrostrictive device according to claim 2, wherein

a shortest distance from said forward end of said stopper member to an inner wall of said cavity portion in a direction of displacing said movable section is not more than a tolerance limit of amplitude of said thin plate sections.

4. A piezoelectric/electrostrictive device according to claim 1, said mechanism comprising:

a cavity portion formed on said inner wall of said fixing section; and

a stopper member provided on said inner wall of said movable section, whose forward end enters said cavity portion.

5. A piezoelectric/electrostrictive device according to claim 4, wherein

a shortest distance from said forward end of said stopper member to an inner wall of said cavity portion in a direction of displacing said movable section is not more than a tolerance limit of amplitude of said thin plate sections.

6. A piezoelectric/electrostrictive device according to claim 1, said mechanism comprising:

two buffer members formed on said inner wall of said fixing section; and

a stopper member provided on said inner wall of said movable section, whose forward end enters between said two buffer members.

7. A piezoelectric/electrostrictive device according to claim 6, wherein:

a shortest distance from said forward end of said stopper member to said buffer members in a direction of displacing said movable section is not more than a tolerance limit of amplitude of said thin plate sections.

8. A piezoelectric/electrostrictive device according to claim 1, said mechanism comprising:

two buffer members formed on said inner wall of said movable section; and

a stopper member provided on said inner wall of said fixing section, whose forward end enters between said two buffer members.

9. A piezoelectric/electrostrictive device according to claim 8, wherein:

a shortest distance from said forward end of said stopper member to said buffer members in a direction of displacing said movable section is not more than a tolerance limit of amplitude of said thin plate sections.

10. A piezoelectric/electrostrictive device according to claim 1, said mechanism comprising:

a projecting portion formed from said inner wall of said fixing portion into said hole, wherein;

a shortest distance from said projecting portion to said thin plate sections is not more than a tolerance limit of amplitude of said thin plate sections.

11. A piezoelectric/electrostrictive device according to claim 1, wherein

said thin plate sections, said movable section, said fixing section and said mechanism comprise an integrated ceramic substrate formed by simultaneously firing a ceramic green laminate, followed by cutting off unnecessary portions.

12. A piezoelectric/electrostrictive device according to claim 11, wherein

said piezoelectric/electrostrictive elements are of a film form and integrated with said ceramic substrate by firing.

13. A piezoelectric/electrostrictive device according to claim 1, wherein

said piezoelectric/electrostrictive elements have a piezoelectric/electrostrictive layer and a pair of electrodes formed on said piezoelectric/electrostrictive layer.

14. A piezoelectric/electrostrictive device according to claim 13, wherein

said piezoelectric/electrostrictive elements are constituted by laminating a plurality of said piezoelectric/electrostrictive layers and said pair of electrodes.

15. The piezoelectric/electrostrictive device according to claim 1, wherein said hole is filled with a gel-like material.

16. A method of producing a piezoelectric/electrostrictive device having a pair of mutually opposing thin plate sections, a movable section, and a fixing section for supporting said thin plate sections and said movable section, said piezoelectric/electrostrictive device comprising:

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

a hole formed by both inner walls of said pair of thin plate sections, an inner wall of said movable section, and an inner wall of said fixing section, comprising the step of;

cutting off a predetermined portion, after forming said piezoelectric/electrostrictive elements on at least the thin plate sections, to produce said piezoelectric/electrostrictive device having a mechanism for restricting amplitude of said thin plate sections.

17. A method for producing a piezoelectric/electrostrictive device having a pair of mutually opposing thin plate sections, a movable section, and a fixing section for supporting said thin plate sections and said movable section, said piezoelectric/electrostrictive device comprising:

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

a hole formed by both inner walls of said pair of thin plate sections, an inner wall of said movable section, and an inner wall of said fixing section, comprising the steps of;

producing a ceramic laminate by firing a ceramic green laminate containing first ceramic green sheets, second ceramic green sheets for constituting a mechanism for restricting amplitude of said thin plate sections and third ceramic green sheets for constituting said thin plate sections integrally, said first ceramic green sheets each having a window for forming at least said hole,

forming said piezoelectric/electrostrictive elements on a part of an outer surface of said ceramic laminate for constituting said thin plate sections; and

producing a piezoelectric/electrostrictive device having said mechanism for restricting amplitude of said thin plate sections by cutting at least once said ceramic laminate having said piezoelectric/electrostrictive element.