Piezoelectric/electrostrictive device

• US 6,465,934 B1
• Filed: 05/05/1999
• Issued: 10/15/2002
• Est. Priority Date: 09/08/1997
• Status: Expired due to Fees

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Kimura, Koji, Ohnishi, Takao, Takeuchi, Yukihisa
• Primary Examiner(s): Ramirez, Nestor
• Assistant Examiner(s): MEDLEY, PETER M
• Application Number:
  US09/214,110
• Time in Patent Office: 1,259 Days
• Field of Search: 310/328, 310/329, 310/321, 310/324, 310/330, 310/331
• US Class Current: 310/321
• CPC Class Codes: B06B 1/06 operating with piezoelectric effect or with electrostriction piezoelectric or electrostrictive devices per se H10N30/00
• CPC Class Codes: B06B 1/0648 of rectangular shape
• CPC Class Codes: B06B 1/0692 with a continuous electrode on one side and a plurality of electrodes on the other side
• CPC Class Codes: G01G 3/16 measuring variations of frequency of oscillations of the body
• CPC Class Codes: G01H 11/08 using piezoelectric devices
• CPC Class Codes: G01N 2035/00217 involving measurement of weight
• CPC Class Codes: G01N 2035/00237 Handling microquantities of analyte, e.g. microvalves, capillary networks
• CPC Class Codes: G01N 2291/02827 Elastic parameters, strength or force
• CPC Class Codes: G01P 15/09 by piezoelectric pick-up
• CPC Class Codes: G01P 15/0922 of the bending or flexing mode type
• CPC Class Codes: G01P 2015/0814 for translational movement of the mass, e.g. shuttle type
• CPC Class Codes: H10N 30/20 with electrical input and mechanical output, e.g. functioning as actuators or vibrators
• CPC Class Codes: H10N 30/2041 Beam type
• CPC Class Codes: H10N 30/2047 Membrane type
• CPC Class Codes: H10N 30/302 Sensors

Abstract

A piezoelectric/electrostrictive device including a substrate and a connection plate having a first end joined to the substrate and an opposed second end extending along a first direction, and first and second opposed sides along a second direction perpendicular to the first direction. A fixing plate is joined to the second end of the connection plate. A first side of a first diaphragm is joined to the first side of the connection plate and an opposed second side of the first diaphragm is joined to the substrate. A first side of a second diaphragm is joined to the substrate and an opposed second side of the second diaphragm is joined to the second side of the connection plate. A piezoelectric/electrostrictive element is provided on at least a portion of at least one planar surface of at least one of the diaphragms.

Claims

1. A piezoelectric/electrostrictive device comprising:

a substrate;

a connection plate having a first end and a second end opposed thereto along a first direction, and a first side and a second side opposed thereto along a second direction perpendicular to said first direction, said first end being joined to said substrate;

a fixing plate joined to said second end of said connection plate;

a first diaphragm having a first side joined to said first side of said connection plate and a second side opposed to said first side along said second direction, said second side of said first diaphragm being joined to said substrate;

a second diaphragm having a first side joined to said substrate and a second side opposed thereto in said second direction, said second side of said second diaphragm being joined to said second side of said connection plate; and

a piezoelectric/electrostrictive element provided on at least a portion of at least one planar surface of at least one of said diaphragms.

2. The piezoelectric/electrostrictive device according to claim 1, wherein the piezoelectric/electrostrictive element is provided on one of said diaphragms and at least one slit is formed on the other one of said diaphragms.

3. The piezoelectric/electrostrictive device according to claim 1 , wherein a slit or constricted portion is formed on the connection plate.

4. The piezoelectric/electrostrictive device according to claim 1, wherein the fixing plate, the connection plate, and the diaphragms are integrally formed from one diaphragm sheet, and the substrate is formed by laminating integrally said diaphragm sheet and a base sheet.

5. The piezoelectric/electrostrictive device according to claim 1, wherein a spring plate is bonded to at least one plane of the connection plate and joined to the substrate or a spring-plate reinforcement portion formed on the substrate.

6. The piezoelectric/electrostrictive device according to claim 5, wherein the spring plate is either formed integrally from an intermediate sheet interposed between and integrated with a diaphragm sheet and a base sheet for the substrate, or formed integrally with a spring-plate reinforcement portion formed integrally with a diaphragm sheet, and formed integrally with the connection plate.

7. The piezoelectric/electrostrictive device according to claim 5, wherein the substrate, the fixing plate, the connection plate, the diaphragm, a spring plate, and a spring-plate reinforcement portion are made of stabilized zirconia or partially-stabilized zirconia.

8. The piezoelectric/electrostrictive device according to claim 5, wherein the shape of at least one of the fixing plate, the connection plate, the diaphragm, and a spring plate is dimension-adjusted by trimming it through laser-beam machining or cutting.

9. The piezoelectric/electrostrictive device according to claim 1, wherein

by using as a center axis a vertical axis passing vertically through the center of a fixed plane which is a connection surface between the fixing plate and the diaphragm,

the piezoelectric/electrostrictive device operates in accordance with at least either of a θ -mode displacement in which the fixing plate displaces like a pendulum in a direction vertical to a side of the fixing plate and vertical to the vertical axis or a φ

-mode displacement in which a swing in a direction vertical to a side of the diaphragm and vertical to the vertical axis centering around the vertical axis displaces like a pendulum while being followed by a swing in a direction parallel with the side of the fixing plate.

10. The piezoelectric/electrostrictive device according to claim 1, wherein at least a portion of the diaphragms and at least a portion of the connection plate are joined to the side of a through-hole formed in the substrate.

11. The piezoelectric/electrostrictive device according to claim 1, wherein at least two piezoelectric/electrostrictive elements are provided at different locations on at least one of the diaphragms, at least one of the piezoelectric/electrostrictive elements is used as a driving element and at least one of the remaining piezoelectric/electrostrictive elements is used as an assistant element for driving the piezoelectric/electrostrictive device.

12. The piezoelectric/electrostrictive device according to claim 1, wherein the piezoelectric/electrostrictive element and a lead used for joining electrically to an electrode of the piezoelectric/electrostrictive element are covered with an insulating coating layer made of a resin or a glass.

13. The piezoelectric/electrostrictive device according to claim 12, wherein the resin is a fluorocarbon resin or a silicone resin.

14. The piezoelectric/electrostrictive device according to claim 12, wherein a shielding layer made of a conductive material is further formed on the surface of the insulating coating layer.

15. The piezoelectric/electrostrictive device according to claim 1, wherein a piezoelectric material forming the piezoelectric/electrostrictive element is made of a material mainly containing a component consisting of lead zirconate, lead titanate, and lead magnesium niobate.

16. The piezoelectric/electrostrictive device according to claim 1, wherein the electrode of the piezoelectric/electrostrictive element is laser-beam-machined or cut and thereby, the effective electrode area of the piezoelectric/electrostrictive element is adjusted.

17. The piezoelectric/electrostrictive device according to claim 1, wherein each of said first and second diaphragms has a third side joined to said substrate.