MICRO FORCE MEASUREMENT DEVICE, MICRO FORCE MEASUREMENT METHOD, AND MICRO SURFACE SHAPE MEASUREMENT PROBE

• US 20070126314A1
• Filed: 12/04/2006
• Published: 06/07/2007
• Est. Priority Date: 12/02/2005
• Status: Active Grant

• Current Assignee: Riken
• Original Assignee: Riken
• Inventors: Morita, Shinya, Watanabe, Yutaka, Ohmori, Hitoshi, Katahira, Kazutoshi, Uehara, Yoshihiro, Lin, Weimin
• Granted Patent: US 7,685,733 B2
• Time in Patent Office: Days
• US Class Current: 310/316.10
• CPC Class Codes: G01B 11/007 feeler heads therefor
• CPC Class Codes: G01B 3/008 Arrangements for controlling the measuring force
• CPC Class Codes: G01B 5/012 Contact-making feeler heads therefor
• CPC Class Codes: G01B 7/012 Contact-making feeler heads therefor

Abstract

There is disclosed a micro surface shape measurement probe including a probe shaft 4 having at a distant end thereof a probe member 2 for contacting an object 1 to be measured, a probe body 21 provided with support means for movably supporting the probe shaft 4 in a non-contact manner, a pressing device for pressing and moving the probe shaft 4 toward the object 1 to be measured, a piezoelectric sensor 8a incorporated in the probe body 21 so that a reactive force acts to a pressing force applied to the probe shaft by the pressing device, a load detecting device 8b to measure a load acting on the piezoelectric sensor, a control device 9 for adjusting the pressing force applied by the pressing device based on the load detected by the load detecting device, and a displacement amount measuring device for measuring a position of the probe member 2 in contact with the object 1 to be measured by the pressing force adjusted by the control device 9.

Claims

1. A micro force measurement device comprising:

a probe member for contacting an object;

a support structure for supporting the probe member in a non-contact manner;

a pressing device fixed to the support structure for pressing the probe member onto the object;

a piezoelectric sensor incorporated in the support structure so that a reactive force to the pressing contact acts, when the pressing device presses the probe member to bring the probe member into contact with the object;

voltage supply means for applying an alternating voltage between opposite polar plates of the piezoelectric sensor; and

impedance detection means for detecting an impedance between the polar plates of the piezoelectric sensor by converting the impedance into a voltage.

3. The micro force measurement device according to claim 1, wherein a value of a frequency of the alternating voltage applied between the opposite polar plates of the piezoelectric sensor is in the vicinity of a resonance frequency of the piezoelectric sensor.

2. A micro force measurement device comprising:

a support structure for supporting an object to be pressed in a non-contact manner;

a pressing device fixed to the support structure for applying a pressing force onto the object to be pressed;

a piezoelectric sensor incorporated in the support structure so that its reactive force acts, when the pressing device applies the pressing force to the object to be pressed;

voltage supply means for applying an alternating voltage between opposite polar plates of the piezoelectric sensor; and

impedance detection means for detecting an impedance between the polar plates of the piezoelectric sensor by converting the impedance into a voltage to detect the impedance.

19. The micro force measurement device according to claim 2, wherein a value of a frequency of the alternating voltage applied between the opposite polar plates of the piezoelectric sensor is in the vicinity of a resonance frequency of the piezoelectric sensor.

4. A micro surface shape measurement probe comprising:

a probe shaft having at a distant end thereof a probe member for contacting an object to be measured;

a probe body provided with support means for movably supporting the probe shaft in a non-contact manner;

a pressing device for pressing and moving the probe shaft toward the object to be measured;

a piezoelectric sensor incorporated in the probe body so that a reactive force to a pressing force applied to the probe shaft by the pressing device acts;

a load detecting device for measuring a load acting on the piezoelectric sensor;

a control device for adjusting the pressing force applied by the pressing device based on the load detected by the load detecting device; and

a displacement amount measuring device for measuring a position of the probe member in contact with the object to be measured under the pressing force adjusted by the control device.

5. The micro surface shape measurement probe according to claim 4, further comprising:

voltage supply means for applying an alternating voltage between opposite polar plates of the piezoelectric sensor; and

impedance detection means for detecting an impedance between the polar plates of the piezoelectric sensor by converting the impedance into a voltage.

6. The micro surface shape measurement probe according to claim 4, wherein a value of a frequency of the alternating voltage applied between opposite polar plates of the piezoelectric sensor is in the vicinity of a resonance frequency of the piezoelectric sensor.

7. The micro surface shape measurement probe according to claim 4, wherein the probe member has a spherical or needle-like distant end and a shaft portion, the distant end being formed integrally with the shaft portion.

8. The micro surface shape measurement probe according to claim 4, wherein the probe member has a spherical shape, a conical shape, a pyramid shape or a combined shape of these shapes, and is coated with a hard coating.

14. The micro surface shape measurement probe according to claim 4, further comprising a contact sensing device for sensing contact between the probe member and the object, by irradiating a contact point between the probe member and the object with laser light through the probe member and detecting the laser light reflected by the contact point.

15. The micro surface shape measurement probe according to claim 4, further comprising a contact sensing device for sensing a contact pressure between the probe member and the object based on a phase difference between laser light emitted to a contact point between the probe member and the object through the contact and laser light reflected by the contact point and returned through the probe member.

9. A micro surface shape measurement probe comprising:

a probe shaft having at a distant end thereof a probe member elastically displaced by a contact pressure between the probe member and an object to be measured;

a probe body provided with support means for movably supporting the probe shaft in a non-contact manner;

a pressing device for pressing and moving the probe shaft toward the object to be measured;

a displacement amount measuring device for measuring a position of the probe shaft and an amount of an elastic displacement of the probe member with respect to the probe shaft, when the probe member comes into contact with the object to be measured;

a micro force detection device for calculating the contact pressure from the position of the probe shaft, the amount of the elastic displacement of the probe member with respect to the probe shaft and a spring constant of the probe member; and

a control device for controlling a pressing force of the pressing device based on the contact pressure calculated by the micro force detection device.

10. The micro surface shape measurement probe according to claim 9, wherein a reflective surface is formed on the back surface of the probe member, a central part of the probe shaft being formed of a hollow portion, extending in an axial direction or formed of a transparent material, extending in an axial direction;

and

the displacement amount measuring device has a laser displacement meter which radiates laser light from a radiating end surface toward the reflective surface through the hollow portion or the transparent material portion to measure a position of the probe member based on the reflected lights from the radiating end surface and the reflective surface.

11. A micro surface shape measurement probe comprising:

a probe shaft having at a distant end thereof a probe member for contacting an object to be measured;

a probe body provided with support means for movably supporting the probe shaft in a non-contact manner;

a pressing device for pressing and moving the probe shaft toward the object to be measured; and

a displacement amount measuring device for measuring a position of the probe member in contact with the object to be measured;

wherein

the probe member is constituted of a plurality of cantilevers arranged symmetrically with respect to the center of the probe member; and

each cantilever has a free end which is positioned in a central part of the probe shaft in a radial direction thereof and comes into contact with the object to be measured, a fixed end fixed to the probe shaft in the vicinity of an outer part thereof in the radial direction, and an elastic connecting portion which connects the free end to the fixed end and is elastically deformed by a contact pressure between the free end and the object to be measured.

12. The micro surface shape measurement probe according to claim 11, wherein a reflective surface is formed on the back surface of the free end of each cantilever;

and

the displacement amount measuring device has a laser displacement meter which radiates laser light from a radiating end surface toward the reflective surface of each cantilever to measure a displacement of the free end of each cantilever based on reflected lights from the radiating end surface and the reflective surface.

13. A micro surface shape measurement probe comprising a probe member having a plurality of cantilevers arranged symmetrically with respect to a center of the probe member for contacting an object;

wherein

each cantilever has a free end which is positioned in an central part in a radial direction for contacting the object, a fixed end fixed in the vicinity of an outer part in the radial direction, and an elastic connecting portion which connects the free end to the fixed end and is elastically deformed by a contact pressure between the free end and the object.

16. A micro surface shape measurement probe comprising:

a probe member for contacting an object to be measured;

a pressing device for pressing and moving the probe member toward the object to be measured;

a displacement amount measuring device for measuring a position of the probe member in contact with the object to be measured;

a swing table for fixing the object to be measured;

swinging means for swinging the swing table in two directions to adjust an angle formed by the probe member and the surface of the object to be measured; and

a calculating device for calculating a position of a contact point from a value measured by the displacement amount measuring device and a swing angle formed by the swinging means.

17. A micro force measurement device for measuring a static micro load acting on a piezoelectric sensor, the micro force measurement device comprising:

a piezoelectric sensor on which a load acts;

voltage supply means for applying an alternating voltage between opposite polar plates of the piezoelectric sensor, with a value of a frequency in the vicinity of a resonance frequency of the piezoelectric sensor; and

impedance detection means for detecting an impedance between the polar plates of the piezoelectric sensor by converting the impedance into a voltage.

18. A micro force detection method comprising:

applying a pressing force toward an object while supporting a probe member in a non-contact manner;

applying an alternating voltage between opposite polar plates of a piezoelectric sensor arranged so that a reactive force of the pressing force acts;

bringing the probe member into contact with the object by the pressing force; and

detecting a contact pressure between the probe member and the object by converting an impedance between the polar plates of the piezoelectric sensor into a voltage.