Piezoelectric/electrostrictive device

• US 6,239,534 B1
• Filed: 12/28/1998
• Issued: 05/29/2001
• Est. Priority Date: 09/08/1997
• Status: Expired due to Fees

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Takeuchi, Yukihisa, Ohnishi, Takao, Kimura, Koji
• Primary Examiner(s): BUDD, MARK OSBORNE
• Application Number:
  US09/242,642
• Time in Patent Office: 883 Days
• Field of Search: 310/328, 310/331, 310/324
• US Class Current: 310/328
• 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 is provided in which a connection plate whose one end in the longitudinal direction is held by two diaphragms and whose other end is held by two other diaphragms is spanned between bottoms of faced concave portions formed on a substrate, and piezoelectric elements are arranged on at least a part of at least one-side plane surface of each of the diaphragms, and the diaphragms are connected with the sides of the concave portions in at least the direction for the diaphragms to hold the connection plate, and a fixing plate is connected to the connection plate so that the longitudinal direction of the fixing plate becomes parallel with the direction for the diaphragms to hold the connection plate. A displacement of the fixing plate generated by applying a voltage to the piezoelectric element is utilized or an electromotive force of the piezoelectric element based on a displacement of the fixing plate is utilized. The piezoelectric/electrostrictive device is preferably used as a positioning- or angle-adjustment mechanism of an optical unit or precision unit, a vibrator or resonator for communication or motive power, an oscillator, a discriminator, an ultrasonic sensor, or an acceleration sensor because the device is able to convert electric energy into mechanical energy such as a mechanical displacement, force, or vibration and vice versa.

Claims

1. A piezoelectric/electrostrictive device comprising:

a substrate having two pairs of concave recesses formed therein, the bottom of each recess defining a diaphragm extending in a first longitudinal direction;

a connection plate having a first end secured between two of said diaphragms and an opposed second end secured between the other two diaphragms, said connection plate extending in a direction substantially perpendicular to said first longitudinal direction and being spanned between and connected to the bottoms of said pairs of concave recesses;

piezoelectric/electrostrictive elements arranged on at least a part of a planar surface of each diaphragm; and

a fixing plate connected to the connection plate and extending in a longitudinal direction substantially parallel to said first longitudinal direction.

2. The piezoelectric/electrostrictive device according to claim 1, wherein a notch is formed at a joint between the fixing plate and the connection plate.

3. The piezoelectric/electrostrictive device according to claim 1, wherein the connection plate is divided into two plates in the spanning direction of the connection plate, and a gap is formed at the central portion of the connection plate, and the fixing plate is connected to a planar surface of the connection plate so as to cross the gap.

4. The piezoelectric/electrostrictive device according to claim 3, wherein a notch is formed at an end of the fixing plate at a position for crossing the divided connection plates.

5. The piezoelectric/electrostrictive device according to claim 1, wherein the fixing plate is connected so as to intersect the connection plate.

6. The piezoelectric/electrostrictive device according to claim 1, wherein a notch is formed in the connection plate between the joint between the connection plate and the substrate and the joint between the connection plate and the diaphragm.

7. The piezoelectric/electrostrictive device according to claim 1, wherein the connection plate is divided into at least two plates in the longitudinal direction of the fixing plate and the fixing plate is connected with at least two divided and formed connection plates.

8. The piezoelectric/electrostrictive device according to claim 2, wherein a hinge portion is provided for the fixing plate from the joint between the fixing plate and the connection plate in the longitudinal direction of the fixing plate.

9. The piezoelectric/electrostrictive device according to claim 1, wherein a set of piezoelectric elements located at diagonal positions are driven at the same phase and another set of piezoelectric elements are driven at the opposite phase centering around a joint between the fixing plate and the connection plate.

10. The piezoelectric/electrostrictive device according to claim 6, wherein a set of piezoelectric elements at line-symmetric positions are driven at the same phase and another set of piezoelectric elements are driven at the opposite phase by using the longitudinal axis of the fixing plate as a symmetric axis.

11. The piezoelectric/electrostrictive device according to claim 1, wherein a pair of diaphragms for holding the connection plate is connected with the connection plate at positions shifted in the thickness direction of the connection plate.

12. The piezoelectric/electrostrictive device according to claim 11, wherein the piezoelectric elements are arranged on planar surface of each of the diaphragms by using a middle point between the connection positions of a pair of diaphragms for holding the connection plate with the connection plate as a point-symmetry center and the piezoelectric elements are driven at the same phase.

18. The piezoelectric/electrostrictive device according to claim 1, wherein every connection of two optional members selected from the connection plate, the diaphragms, and the substrate is made at each side.

20. The piezoelectric/electrostrictive device according to claim 1, wherein at least the connection plate, the diaphragms, and the substrate are integrally formed.

22. The piezoelectric/electrostrictive device according to claim 1, wherein at least each portion of a device excluding the piezoelectric element is formed by a green-sheet laminating method.

24. The piezoelectric/electrostrictive device according to claim 1, wherein the displacing mode of the fixing plate uses at least any one of the displacement of uniaxial mode of the fixing plate in its longitudinal direction, displacement of in-plane rotation mode about the vicinity of a joint between the fixing plate and the connection plate, and displacement of rotation mode about the longitudinal axis of the connection plate.

25. The piezoelectric/electrostrictive device according to claim 24, wherein the displacement of in-plane rotation mode is based on a magnification mechanism for magnifying a displacement of the piezoelectric element in two steps.

28. The piezoelectric/electrostrictive device according to claim 1, wherein one piezoelectric element is divided into two elements, one of the divided piezoelectric elements is used as a driving element and the other of the divided piezoelectric element is used as an auxiliary element.

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

31. The piezoelectric/electrostrictive device according to claim 30, wherein the resin includes fluorocarbon polymer or silicone resin.

32. The piezoelectric/electrostrictive device according to claim 30, wherein a shielding layer made of a conductive member is further formed on the surface of the insulating coating layer.

36. The piezoelectric/electrostrictive device according to claim 1, wherein the substrate, the fixing plate, the connection plate, and the diaphragms are made of fully stabilized zirconia or partially stabilized zirconia.

38. The piezoelectric/electrostrictive device according to claim 1, wherein a piezoelectric film of the piezoelectric element consists essentially of lead zirconate, lead titanate, and lead magnesium niobate as major component.

40. The piezoelectric/electrostrictive device according to claim 1, wherein the shape of any one of the fixing plate, the connection plate, and the diaphragms is dimension-adjusted by trimming it through laser-beam machining or mechanical machining.

42. The piezoelectric/electrostrictive device according to claim 1, wherein the available electrode area of the piezoelectric element is adjusted by laser-beam machining or mechanical machining.

44. The piezoelectric/electrostrictive device according to claim 1, wherein the piezoelectric/electrostrictive device is constituted with two or more piezoelectric/electrostrictive devices in which at least their fixing plates are connected with each other.

13. A piezoelectric/electrostrictive device comprising:

a substrate having a concave recess formed therein, said recess being defined by at least two opposed sides and a third side between said two opposed sides;

a connection plate spanned between opposed sides of said concave recess;

at least two diaphragms, on which piezoelectric/electrostrictive elements are arranged on at least a part of at least one planar surface thereof, said diaphragms being spanned between the connection plate and the third side of said concave recess; and

a fixing plate connected to the connection plate, the longitudinal direction of the fixing plate being substantially parallel with the spanning direction of the diaphragms.

14. The piezoelectric/electrostrictive device according to claim 13, wherein at least two pairs of diaphragms constituted so as to face a plane surface are spanned between the connection plate and the bottom of the concave portion of the substrate.

15. The piezoelectric/electrostrictive device according to claim 13, wherein a notch is formed at a joint between the fixing plate and the connection plate.

16. The piezoelectric/electrostrictive device according to claim 13, wherein the connection plate is divided into two plates in the spanning direction of the connection plate, a gap is formed at the central portion of the connection plate, and the fixing plate is connected to the planar surface of the connection plate so as to cross the gap.

17. The piezoelectric/electrostrictive device according to claim 16, wherein a notch is formed at an end of the fixing plate at a position crossing the divided connection plates.

19. The piezoelectric/electrostrictive device according to claim 13, wherein every connection of two optional members selected from the connection plate, the diaphragms, and the substrate is made at each side.

21. The piezoelectric/electrostrictive device according to claim 13, wherein at least the connection plate, the diaphragms, and the substrate are integrally formed.

23. The piezoelectric/electrostrictive device according to claim 13, wherein at least each portion of a device excluding the piezoelectric element is formed by a green-sheet laminating method.

26. The piezoelectric/electrostrictive device according to claim 13, wherein the displacing mode of the fixing plate uses at least any one of the displacement of uniaxial mode of the fixing plate in its longitudinal direction, displacement of in-plane rotation mode about the vicinity of a joint between the fixing plate and the connection plate, and displacement of rotation mode about the longitudinal axis of the connection plate.

27. The piezoelectric/electrostrictive device according to claim 26, wherein the displacement of in-plane rotation mode is based on a magnification mechanism for magnifying the displacement of the piezoelectric element in two steps.

29. The piezoelectric/electrostrictive device according to claim 13, wherein one piezoelectric element is divided into two elements, one of the divided piezoelectric elements is used as a driving element and the other of the divided piezoelectric element is used as an auxiliary element.

33. The piezoelectric/electrostrictive device according to claim 13, wherein the piezoelectric element and an electrode lead electrically connected with the piezoelectric element are covered with an insulating coating layer made of resin or glass.

34. The piezoelectric/electrostrictive device according to claim 33, wherein the resin includes fluorocarbon polymer or silicone resin.

35. The piezoelectric/electrostrictive device according to claim 33, wherein a shielding layer made of a conductive member is further formed on the surface of the insulating coating layer.

37. The piezoelectric/electrostrictive device according to claim 13, wherein the substrate, the fixing plate, the connection plate, and the diaphragms are made of fully stabilized zirconia or partially stabilized zirconia.

39. The piezoelectric/electrostrictive device according to claim 13, wherein a piezoelectric film of the piezoelectric element consists essentially of lead zirconate, lead titanate, and lead magnesium niobate as major component.

41. The piezoelectric/electrostrictive device according to claim 13, wherein the shape of any one of the fixing plate, the connection plate, and the diaphragms is dimension-adjusted by trimming it through laser-beam machining or mechanical machining.

43. The piezoelectric/electrostrictive device according to claim 13, wherein the available electrode area of the piezoelectric element is adjusted by laser-beam machining or mechanical machining.

45. The piezoelectric/electrostrictive device according to claim 13, wherein the piezoelectric/electrostrictive device is constituted with two or more piezoelectric/electrostrictive devices in which at least their fixing plates are connected with each other.