DIELECTROSTRICTIVE SENSOR FOR MEASURING DEFORMATION

• US 20090249885A1
• Filed: 04/23/2008
• Published: 10/08/2009
• Est. Priority Date: 04/08/2008
• Status: Active Grant

• Current Assignee: Ho Young Lee, Yiyan Peng, Yuri Michael Shkel
• Original Assignee: Ho Young Lee, Yiyan Peng, Yuri Michael Shkel
• Inventors: Lee, Ho Young, Peng, Yiyan, Shkel, Yuri Michael
• Granted Patent: US 7,726,199 B2
• Time in Patent Office: Days
• US Class Current: 73/780
• CPC Class Codes: G01B 7/22 using change in capacitance
• CPC Class Codes: G01L 1/142 using capacitors

Abstract

An apparatus and method directed to a solid-state capacitance sensor for measuring a strain force on a dielectric including at least one pair of electrostriction sensors each sensor having at least two electrodes and each having a central axis. The central axes are disposed in a common plane and are oriented substantially mutually perpendicularly to one another. Preferably, at least two pairs of sensors, forming a rosette, are provided to facilitate multi-component analysis of a sample having dielectric properties under stress/strain.

Claims

1. A solid-state capacitance sensor for measuring deformation of a sample having dielectric properties, the sensor comprising:

more than two pairs of electrostriction sensors that are shifted about 45 degrees with respect to one another to form a rosette each sensor having at least two electrodes and each having a central axis, wherein the central axes are disposed in a common plane and are oriented substantially mutually perpendicularly to one another.

2. The sensor of claim 1, further comprising a measuring circuit that measures capacitance of each sensor in response to the deformation, and wherein a difference in the measured capacitance is indicative of an amount and a direction of the deformation.

3. The sensor of claim 2, wherein the measuring circuit is a capacitor bridge circuit.

4. The sensor of claim 1, wherein the rosette measures components of the deformation each having a principal axis.

7. The sensor of claim 4, wherein the principal axes are substantially orthogonal to one another.

8. The sensor of claim 1, wherein the more than two pairs of sensors includes at least four pairs of sensors that are shifted about 45 degrees with respect to one another and define a rosette, wherein the rosette measures multiple components of the deformation.

9. The sensor of claim 8, wherein the sensors include interdigitated electrodes and are pie-piece shaped.

10. The sensor of claim 1, wherein the electrodes include at least three interdigitated electrodes.

11. The sensor of claim 1, wherein the electrodes are supported by a substrate.

12. The sensor of claim 11, wherein the sensors are microfabricated using a CMOS technique.

13. The sensor of claim 1, wherein the deformation is at least one of a strain and a stress.

14. The sensor of claim 1, further comprising a thin layer of material disposed between the sensors and the sample to facilitate dielectric coupling between the sensors and the sample.

15. The sensor of claim 1, wherein the sensors are disposed adjacent to the sample.

16. The sensor of claim 1, wherein the sample is tempered glass and the sensors measure at least one of a group including stress and strain during formation of the glass.

17. The sensor of claim 1, wherein the sample is anisotropic.

18. The sensor of claim 1, wherein the sensors do not dissipate heat.

5. (canceled)

6. (canceled)

19. A method of sensing a deformation of a sample having dielectric properties, the method comprising:

providing more than two pairs of electrostriction sensors that are shifted about 45 degrees with respect to one another to form a rosette, each sensor having at least two electrodes and each having a central axis, wherein the central axes are disposed in a common plane and are oriented substantially mutually perpendicularly to one another;

positioning the sensors adjacent to the dielectric sample having a dielectric property; and

measuring a change in capacitance associated with each sensor.

20. The method of claim 19, further comprising computing a difference in the measured capacitance associated with each pair, and determining the deformation by computing a change in a dielectric property of the sample based on the difference;

and

wherein the electrodes do not substantially move such that the determined deformation is based substantially only on the electrostrictive response of the dielectric to the deformation.

22. The method of claim 19, wherein the more than two pairs of sensors includes at least four pairs of sensors and are shifted about 45 degrees with respect to one another, wherein the sensor pairs detect multiple components of the deformation

23. The method of claim 19, wherein the measuring step is performed using a capacitive bridge.

24. The method of claim 19, wherein the sensors include interdigitated electrodes mounted to a substrate.

21. (canceled)

25-27. -27. (canceled)

28. A solid-state capacitance sensor for measuring deformation of a sample having dielectric properties, the sensor comprising:

at least one pair of electrostriction sensors each sensor having at least two electrodes and each having a central axis, wherein the central axes are disposed in a common plane and are oriented substantially mutually perpendicularly to one another; and

wherein the sample is tempered glass and the sensors measure at least one of a group including stress and strain during formation of the glass.