METHOD FOR TESTING PIEZOELECTRIC/ELECTROSTRICTIVE DEVICE, TESTING APPARATUS, AND METHOD FOR ADJUSTING PIEZOELECTRIC/ELECTROSTRICTIVE DEVICE

• US 20110025171A1
• Filed: 10/15/2010
• Published: 02/03/2011
• Est. Priority Date: 04/18/2008
• Status: Active Grant

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Goto, Naoki, Ohnishi, Takao
• Granted Patent: US 8,304,961 B2
• Time in Patent Office: Days
• US Class Current: 310/328
• CPC Class Codes: G01N 2291/2697 Wafer or (micro)electronic parts
• CPC Class Codes: G01N 29/12 by measuring frequency or resonance of acoustic waves measuring frequency or resonant frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04, G01H13/00; acoustic resonators G10K11/04; vibration or shock testing of structures G01M7/00
• CPC Class Codes: G01N 29/4454 Signal recognition, e.g. specific values or portions, signal events, signatures
• CPC Class Codes: H10N 30/04 Treatments to modify a piezoelectric or electrostrictive property, e.g. polarisation characteristics, vibration characteristics or mode tuning
• CPC Class Codes: H10N 30/06 Forming electrodes or interconnections, e.g. leads or terminals
• CPC Class Codes: H10N 30/2047 Membrane type
• CPC Class Codes: H10N 30/87 Electrodes or interconnections, e.g. leads or terminals
• CPC Class Codes: Y10T 29/42 Piezoelectric device making
• CPC Class Codes: Y10T 29/49004 including measuring or testing of device or component part

Abstract

There is provided a method for testing a piezoelectric/electrostrictive actuator, wherein the displacement of a piezoelectric/electrostrictive actuator is estimated on the basis of the relations between one or more frequency characteristic values selected from the group consisting of the heights and areas of the peaks of the resonance waveforms and the difference of the maximum and minimum of the first order or first to higher orders of the resonance frequency characteristic values of the piezoelectric/electrostrictive actuator and the k-th order (k=1 to 4) of the first or first to higher orders of resonance frequencies. According to this piezoelectric/electrostrictive actuator testing method, a piezoelectric/electrostrictive actuator can be tested with high precision without actually driving the same as a product and without being accompanied by any disassembly/breakage.

Claims

1. A method for testing a piezoelectric/electrostrictive actuator, wherein the displacement of a piezoelectric/electrostrictive actuator is estimated on the basis of the relations between one or more frequency characteristic values selected from the group consisting of the heights and areas of the peaks of the resonance waveforms and the difference of the maximum and minimum of the first order or first to higher orders of the resonance frequency characteristic values of the piezoelectric/electrostrictive actuator and the k-th order (k=1 to 4) of the first or first to higher orders of resonance frequencies.

2. The method for testing a piezoelectric/electrostrictive actuator according to claim 1, wherein the relation is a relation of dividing the one or more frequency characteristic values selected from the group consisting of the heights and areas of the peaks of the resonance waveforms and the difference of the maximum and minimum of the first order of the resonance frequency characteristic values of the piezoelectric/electrostrictive actuator by the k-th order (k=1 to 4) of the first order of resonance frequency to estimate the displacement of the piezoelectric/electrostrictive actuator by the calculated value obtained by the division.

3. The method for testing a piezoelectric/electrostrictive actuator according to claim 1, wherein the relation is a relation of dividing a sum of the one or more frequency characteristic values selected from the group consisting of the heights and areas of the peaks of the resonance waveforms and the difference of the maximum and minimum of the first to higher orders of the resonance frequency characteristic values of the piezoelectric/electrostrictive actuator by the k-th order (k=1 to 4) of the first order of resonance frequency to estimate the displacement of the piezoelectric/electrostrictive actuator by the calculated value obtained by the division.

4. The method for testing a piezoelectric/electrostrictive actuator according to claim 1, wherein the relation is a relation of dividing the one or more frequency characteristic values selected from the group consisting of the heights and areas of the peaks of the resonance waveforms and the difference of the maximum and minimum of the resonance frequency characteristic value for each of the resonances of the first to higher orders of the piezoelectric/electrostrictive actuator by the k-th order (k=1 to 4) of resonance frequency and obtaining the sum of the values for each of the resonances to estimate the displacement of the piezoelectric/electrostrictive actuator by the calculated value obtained by the sum.

5. The method for testing a piezoelectric/electrostrictive actuator according to claim 2, wherein the displacement of the piezoelectric/electrostrictive actuator is estimated by a value obtained by further multiplying the calculated value by the capacitance of the piezoelectric/electrostrictive actuator.

21. A method for adjusting a piezoelectric/electrostrictive actuator, comprising:

estimating the displacements of a plurality of piezoelectric/electrostrictive actuators by the use of a method for testing a piezoelectric/electrostrictive actuator according to claim 1, and

trimming an upper electrode with regard to at least some of the plurality of actuators to adjust the displacement of the piezoelectric/electrostrictive actuators uniformly.

22. The method for adjusting a piezoelectric/electrostrictive actuator according to claim 21, where the trimming is performed by a processing method by laser irradiation.

23. The method for adjusting a piezoelectric/electrostrictive actuator according to claim 21, wherein the trimming is performed by forming at least one pattern in the vicinity of the central portion of the upper electrode.

24. The method for adjusting a piezoelectric/electrostrictive actuator according to claim 23, wherein, when the pattern has circular through-holes, the through-holes have different diameters.

25. The method for adjusting a piezoelectric/electrostrictive actuator according to claim 23, wherein, when the pattern has slits, the slits have different widths.

26. A method for adjusting a piezoelectric/electrostrictive actuator comprising:

estimating the displacements of a plurality of piezoelectric/electrostrictive actuators by the use of a method for testing a piezoelectric/electrostrictive actuator according to claim 1, and

trimming a piezoelectric/electrostrictive body with regard to at least some of the plurality of piezoelectric/electrostrictive actuators to adjust the displacement of the piezoelectric/electrostrictive actuators uniformly.

27. The method for adjusting a piezoelectric/electrostrictive actuator according to claim 26, wherein both the piezoelectric/electrostrictive body and the upper electrode are trimmed with regard to at least some of the plurality of piezoelectric/electrostrictive actuators.

28. The method for adjusting a piezoelectric/electrostrictive actuator according to claim 21, wherein the trimming is performed in at least a portion where the maximum displacement of the piezoelectric/electrostrictive actuator is generated.

29. The method for adjusting a piezoelectric/electrostrictive actuator according to claim 21, wherein the trimming is performed in a portion having the maximum amplitude in the first order of the resonance mode.

30. A piezoelectric/electrostrictive actuator obtained by adjusting the displacement uniformly by using a method for adjusting a piezoelectric/electrostrictive actuator according to claim 21.

6. An apparatus for testing piezoelectric/electrostrictive actuator, wherein the apparatus is provided with a means for estimating the displacement of the piezoelectric/electrostrictive actuator on the basis of the relations between one or more frequency characteristic values selected from the group consisting of the heights and areas of the peaks of the resonance waveforms and the difference of the maximum and minimum of the first order or first to higher orders of the resonance frequency characteristic values of the piezoelectric/electrostrictive actuator and the k-th order (k=1 to 4) of the first or first to higher orders of resonance frequencies.

7. The apparatus for testing piezoelectric/electrostrictive actuator according to claim 6, wherein the relation is a relation of dividing the one or more frequency characteristic values selected from the group consisting of the heights and areas of the peaks of the resonance waveforms and the difference of the maximum and minimum of the first order of the resonance frequency characteristic values of the piezoelectric/electrostrictive actuator by the k-th order (k=1 to 4) of the first order of resonance frequency, and wherein the apparatus is provided with a means for estimating the displacement of the piezoelectric/electrostrictive actuator by the calculated value obtained by the division.

8. The apparatus for testing piezoelectric/electrostrictive actuator according to claim 6, wherein the relation is a relation of dividing a sum of the one or more frequency characteristic values selected from the group consisting of the heights and areas of the peaks of the resonance waveforms and the difference of the maximum and minimum of the first to higher orders of the resonance frequency characteristic values of the piezoelectric/electrostrictive actuator by the k-th order (k=1 to 4) of the first order of resonance frequency, and wherein the apparatus is provided with a means for estimating the displacement of the piezoelectric/electrostrictive actuator by the calculated value obtained by the division.

9. The apparatus for testing piezoelectric/electrostrictive actuator according to claim 6, wherein the relation is a relation of dividing the one or more frequency characteristic values selected from the group consisting of the heights and areas of the peaks of the resonance waveforms and the difference of the maximum and minimum of the resonance frequency characteristic value for each of the resonances of the first to higher orders of the piezoelectric/electrostrictive actuator by the k-th order (k=1 to 4) of resonance frequency and obtaining the sum of the values for each of the resonances, and wherein the apparatus is provided with a means for estimating the displacement of the piezoelectric/electrostrictive actuator by the calculated value obtained by the sum.

10. The apparatus for testing piezoelectric/electrostrictive actuator according to claim 7, wherein the apparatus is provided with a means for estimating the displacement of the piezoelectric/electrostrictive actuator by a value obtained by further multiplying the calculated value by the capacitance of the piezoelectric/electrostrictive actuator.

11-20. -20. (canceled)

31-40. -40. (canceled)