Piezoelectric/electrostrictive device and method for fabricating the same

• US 20020175599A1
• Filed: 03/12/2002
• Published: 11/28/2002
• Est. Priority Date: 03/02/2001
• Status: Active Grant

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Nanataki, Tsutomu, Kimura, Koji, Takeuchi, Yukihisa
• Granted Patent: US 6,931,698 B2
• Time in Patent Office: Days
• US Class Current: 310/330
• CPC Class Codes: G02B 26/0858 the reflecting means being moved or deformed by piezoelectric means
• CPC Class Codes: H10N 30/074 by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing
• CPC Class Codes: H10N 30/088 by cutting or dicing
• 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: Y10T 29/42 Piezoelectric device making
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 29/49005 Acoustic transducer
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/4908 Acoustic transducer

Abstract

A piezoelectric/electrostrictive device includes a functional element. The functional element includes a base portion; a deformable portion assuming the form of a thin plate and extending from the base portion to thereby form a plane; a piezoelectric/electrostrictive element formed on the deformable portion; and a reflective portion extending from the deformable portion so as to form an active plane intersecting with the plane of the deformable portion, and having a light-reflecting member disposed on the active plane. Operation of the piezoelectric/electrostrictive element causes the deformable portion to be deformed in a direction substantially perpendicular to the plane of the deformable portion to thereby change a reflection angle of light reflected from the reflective portion.

Claims

1. A piezoelectric/electrostrictive device comprising a functional element which comprises:

a base portion;

a deformable portion assuming the form of a thin plate and extending from said base portion to thereby form a plane;

a piezoelectric/electrostrictive element tightly fixed to at least said deformable portion; and

a reflective portion extending from said deformable portion so as to form an active plane intersecting with the plane of said deformable portion, and having a light-reflecting member disposed on the active plane, wherein

upon operation of said piezoelectric/electrostrictive element, said deformable portion deforms in a direction substantially perpendicular to the plane of said deformable portion to thereby change a reflection angle of light reflected from said reflective portion.

2. A piezoelectric/electrostrictive device according to claim 1, wherein said reflective portion extends from an end part of said deformable portion while having a width substantially equal to that of said deformable portion.

3. A piezoelectric/electrostrictive device according to claim 1, comprising a plurality of said functional elements,

wherein said plurality of functional elements are arranged linearly adjacent to one another.

4. A piezoelectric/electrostrictive device according to claim 3, wherein said plurality of functional elements have said respective base portions formed into a common base portion.

5. A piezoelectric/electrostrictive device according to claim 1, comprising a plurality of said functional elements,

wherein said plurality of functional elements are arranged in a matrix and adjacent to one another.

6. A piezoelectric/electrostrictive device according to claim 5, wherein at least a column of said functional elements in the matrix has said respective base portions formed into a common base portion.

7. A piezoelectric/electrostrictive device according to claim 1, wherein said base portion, said deformable portion, and said reflective portion of said functional element are formed of a unitary body of ceramics.

8. A piezoelectric/electrostrictive device according to claim 7, wherein said piezoelectric/electrostrictive element is a film-type piezoelectric/electrostrictive element and is integrated with said deformable portion through firing.

9. A piezoelectric/electrostrictive device comprising a functional element which comprises:

a base portion;

a deformable portion assuming the form of a thin plate and extending from said base portion to thereby form a plane;

a piezoelectric/electrostrictive element tightly fixed to at least said deformable portion;

a reflective portion extending from said deformable portion so as to form an active plane intersecting with the plane of said deformable portion, and having a light-reflecting member disposed on the active plane; and

a holder portion extending from said base portion in opposition to said deformable portion to thereby hold a part of said reflective portion, wherein

upon operation of said piezoelectric/electrostrictive element, said deformable portion deforms in a direction substantially perpendicular to the plane of said deformable portion to thereby change a reflection angle of light reflected from said reflective portion without deformation of said holder portion.

10. A piezoelectric/electrostrictive device according to claim 9, wherein said reflective portion extends from an end part of said deformable portion while having a width substantially equal to that of said deformable portion.

11. A piezoelectric/electrostrictive device according to claim 9, comprising a plurality of said functional elements,

wherein said plurality of functional elements are arranged linearly adjacent to one another.

12. A piezoelectric/electrostrictive device according to claim 11, wherein said plurality of functional elements have said respective base portions formed into a common base portion.

13. A piezoelectric/electrostrictive device according to claim 9, comprising a plurality of said functional elements,

wherein said plurality of functional elements are arranged in a matrix and adjacent to one another.

14. A piezoelectric/electrostrictive device according to claim 13, wherein at least a column of said functional elements in the matrix has said respective base portions formed into a common base portion.

15. A piezoelectric/electrostrictive device according to claim 9, wherein said base portion, said deformable portion, said reflective portion, and said holder portion of said functional element are formed of a unitary body of ceramic.

16. A piezoelectric/electrostrictive device according to claim 15, wherein said piezoelectric/electrostrictive element is a film-type piezoelectric/electrostrictive element and is integrated with said deformable portion through firing.

18. A method for fabricating a piezoelectric/electrostrictive device according to claim 17, further comprising the steps of:

preparing a plurality of unitary bodies of ceramics that heve not undergone said second cutting step;

bonding the plurality of unitary bodies of ceramics at those parts of the thick portions which are to become base portions, while spacers are interposed therebetween; and

forming a light-reflecting member on the reflective portions.

19. A method for fabricating a piezoelectric/electrostrictive device according to claim 18, wherein said second cutting step is a step of cutting at least the residual thick portion, the light-reflecting member, and the thin portion.

20. A method for fabricating a piezoelectric/electrostrictive device according to claim 18, wherein

said element forming step is a step of forming a plurality of piezoelectric/electrostrictive elements arranged such that substantially the same clearance is established between the piezoelectric/electrostrictive elements;

said method further comprises a step of slitting, before said second cutting step, the thin portion between the piezoelectric/electrostrictive elements to thereby form slits in the thin portion; and

said second cutting step is a step of cutting at least the residual thick portion and the light-reflecting member along planes aligned with the slits.

21. A method for fabricating a piezoelectric/electrostrictive device according to claim 20, wherein

said step of slitting the thin portion is a step of forming the slits in the thin portion through laser beam processing;

and

said second cutting step is a step of cutting, through laser beam processing, the residual thick portion and the light-reflecting member.

22. A method for fabricating a piezoelectric/electrostrictive device according to claim 18, wherein said step of forming the light-reflecting member comprises a polishing step of polishing, before the light-reflecting member is formed, the cut surface formed as a result of cutting in said first cutting step, and wherein said method further comprises the steps of:

filling a filler into gaps between the plurality of unitary bodies after the plurality of unitary bodies are bonded at the thick portions while the spacers are interposed therebetween, and before said polishing step; and

removing the filler after said second cutting step.

17. A method for fabricating a piezoelectric/electrostrictive device in which a thin deformable portion made of ceramics and extending from a thick base portion formed of ceramics is deformed by a piezoelectric/electrostrictive element tightly fixed to at least the deformable portion to thereby change angle of a reflective portion made of ceramics and extending from the deformable portion, said method comprising:

a lamination step of placing a ceramic green sheet on another ceramic green sheet having a substantially rectangular through-hole at a central portion thereof, in such a manner as to cover the through-hole;

a firing step of firing the laminated ceramic green sheets to thereby form a unitary body of ceramics having a thick portion and a thin portion;

an element forming step of forming a piezoelectric/electrostrictive element on at least the thin portion;

a first cutting step of cutting off a part of the thick portion from the unitary body so as to leave a residual thick portion having a predetermined thickness as measured from an end of the thin portion after said firing step to form the unitary body of ceramics, and after or before said element forming step of forming the piezoelectric/electrostrictive element,; and

a second cutting step of cutting the residual thick portion along a plane perpendicularly intersecting with a cut surface formed as a result of cutting in said first cutting step, to thereby form the reflective portion having the predetermined thickness, the thin deformable portion, and the thick base portion.