Method for fabricating piezoelectric/electrostrictive device

• US 6,931,698 B2
• Filed: 03/12/2002
• Issued: 08/23/2005
• Est. Priority Date: 03/02/2001
• Status: Expired due to Fees

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Kimura, Koji, Takeuchi, Yukihisa, Nanataki, Tsutomu
• Primary Examiner(s): Kim, Paul D.
• Application Number:
  US10/096,059
• Publication Number:
  US 20020175599A1
• Time in Patent Office: 1,260 Days
• Field of Search: 29/253.5, 295/921, 295/94, 296/021, 296/09, 216/65, 310/324, 310/328, 310/330, 310/331, 310/335, 310/348, 451/5, 451/41
• US Class Current: 29/25.35
• 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 is provided including 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 method of fabricating a piezoelectric/electrostrictive device comprising a ceramic thin deformable portion that extends from a ceramic thick base portion and wich is deformed by a piezoelectric/electrostrictive element that is tightly fixed to at least said thin deformable portion to thereby change an angle of a ceramic reflective portion that extends beyond said thin deformable portion, said method comprising the steps of:

laminating a first ceramic green sheet on a second ceramic green sheet having a substantially rectangular through-hole at a central portion thereof, such that said first ceramic green sheet covers said through-hole in said second ceramic green sheet;

firing said laminated ceramic green sheets to thereby form a unitary ceramic body having a thick portion and a thin portion;

forming a piezoelectric/electrostrictive element on at least said thin portion;

performing a first cutting step to remove a part of said thick portion of said unitary ceramic body such that said unitary ceramic body comprises said thin portion and a residual thick portion having a cut surface and also having a predetermined thickness as measured from an end of said thin portion after said firing step, and after or before said step of forming said piezoelectric/electrostrictive element, said residual thick portion further comprising a reflective portion having said predetermined thickness and an opposed thick base portion having said predetermined thickness and being spaced a distance from said reflective portion by said thin portion;

forming a light-reflecting member on at least a portion of said reflective portion; and

performing a second cutting step to cut said residual thick portion along a plane perpendicularly intersecting with said cut surface;

wherein said step of forming said light-reflecting member is performed before said second cutting step.

2. The method of fabricating a piezoelectric/electrostrictive device according to claim 1, further comprising the steps of:

preparing a plurality of said unitary ceramic bodies up to said second cutting step;

bonding said plurality of unitary ceramic bodies at parts of said residual thick portions thereof corresponding to said thick base portions and interposing spacers therebetween to form a bonded plurality of unitary ceramic bodies; and

forming said light-reflecting member on said reflective portions of said bonded plurality of unitary ceramic bodies after said bonding step and before said second cutting step.

3. The method of fabricating a piezoelectric/electrostrictive device according to claim 2, wherein said second cutting step comprises cutting at least said residual thick portions, said light-reflecting member, and said thin portions of said bonded unitary ceramic bodies.

4. The method of fabricating a piezoelectric/electrostrictive device according to claim 2, wherein said step of forming said piezoelectric/electrostrictive element comprises forming a plurality of piezoelectric/electrostrictive elements arranged such that substantially the same clearance is established between said piezoelectric/electrostrictive elements;

wherein said method further comprises a step of forming a slit in a part of said thin portion between said piezoelectric/electrostrictive elements before said second cutting step;

wherein said second cutting step comprises cutting at least said residual thick portions and said light-reflecting member along planes aligned with said slits.

5. The method of fabricating a piezoelectric/electrostrictive device according to claim 4, wherein said slits are formed in said thin portion using laser beam processing;

and

wherein said residual thick portions and said light-reflecting member are cut using laser beam processing during said second cutting step.

6. The method of fabricating a piezoelectric/electrostrictive device according to claim 2, wherein said step of forming the light-reflecting member further comprises polishing, said cut surface before said light-reflecting member is formed thereon:

and

wherein said method further comprises the steps of;

filling a filler into gaps between said bonded plurality of unitary ceramic bodies before said polishing step; and

removing said filler after said second cutting step.

7. A method of fabricating a piezoelectric/electrostrictive device comprising a ceramic thin deformable portion that extends from a ceramic thick base portion and which is deformed by a piezoelectric/electrostrictive element that is tightly fixed to at least said thin deformable portion to thereby change an angle of a ceramic reflective portion that extends beyond said thin deformable portion, said method comprising the steps of:

laminating a first ceramic green sheet on a second ceramic green sheet having a substantially rectangular through-hole at a central portion thereof such that said first ceramic green sheet covers said through-hole in said second ceramic green sheet;

firing said laminated ceramic green sheets to thereby form a unitary ceramic body having a thick portion and a thin portion;

forming a piezoelectric/electrostrictive element on at least said thin portion;

performing a first cutting step to remove a part of said thick portion of said unitary ceramic body such that said unitary ceramic body comprises said thin portion and a residual thick portion having a cut surface and also having a predetermined thickness as measured from an end of said thin portion after said firing step, and after or before said step of forming said piezoelectric/electrostrictive element, said residual thick portion further comprising a reflective portion having said predetermined thickness and an opposed thick base portion having said predetermined thickness and being spaced a distance from said reflective portion by said thin portion;

repeating the above steps to provide a plurality of said unitary ceramic bodies;

bonding said plurality of unitary ceramic bodies at parts of said residual thick portions thereof corresponding to said thick base portions and interposing spacers therebetween to form a bonded plurality of unitary ceramic bodies;

forming a light-reflecting member on said reflective portions of said bonded plurality of unitary ceramic bodies; and

performing a second cutting step to cut said residual thick portions along a plane perpendicularly intersecting with said cut surfaces.

8. The method of fabricating a piezoelectric/electrostrictive device according to claim 7, wherein said second cutting step comprises cutting at least said residual thick portions, said light-reflecting member, and said thin portions of said bonded unitary ceramic bodies.

9. The method of fabricating a piezoelectric/electrostrictive device according to claim 7, wherein said step of forming said piezoelectric/electrostrictive element comprises forming a plurality of piezoelectric/electrostrictive elements arranged such that substantially the same clearance is established between said piezoelectric/electrostrictive elements;

wherein said method further comprises a step of forming a slit in a part of said thin portion between said piezoelectric/electrostrictive elements before said second cutting step; and

wherein said second cutting step comprises cutting at least said residual thick portions and said light-reflecting member along planes aligned with said slits.

10. The method of fabricating a piezoelectric/electrostrictive device according to claim 9, wherein said slits are formed in said thin portion using laser beam processing;

and

wherein said residual thick portions and said light-reflecting member are cut using laser beam processing during said second cutting step.

11. The method of fabricating a piezoelectric/electrostrictive device according to claim 7, wherein said step of forming said light-reflecting member further comprises polishing said cut surface before said light-reflecting member is formed thereon, and wherein said method further comprises the steps of filling a filler into gaps between said bonded plurality of unitary ceramic bodies before said polishing step, and removing said filler after said second cutting step.