Profilometer and method for measuring, and method for manufacturing object of surface profiling

• US 6,763,319 B2
• Filed: 05/31/2002
• Issued: 07/13/2004
• Est. Priority Date: 06/04/2001
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Takeuchi, Hiroyuki, Yoshizumi, Keiichi, Kubo, Keishi, Handa, Koji
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): Sun, Xiuqin
• Application Number:
  US10/159,565
• Publication Number:
  US 20020183964A1
• Time in Patent Office: 774 Days
• Field of Search: 702/168, 700/56, 700/193, 356/609, 731/05
• US Class Current: 702/168
• CPC Class Codes: G01B 5/012 Contact-making feeler heads therefor

Abstract

A stylus having a curvature radius of 1 mm or less is attached to the extremity of a probe. When the profile of an object is measured with high precision by causing the stylus to follow a measurement surface of the object, a reference ball for calibration is first measured, thereby surface profiling the object. From the measurement data, a contact position where the stylus contacts with the object is determined. A positional error caused by a curvature radius of the stylus is corrected by using an angle of inclination of the measurement surface in that contact position. The amount of profile error in the contact position is extracted by using the profile error data pertaining to the stylus determined by measurement of the reference ball. The amount of profile error is added to the measurement data, thereby correcting the profile error caused by the curvature radius of the stylus.

Claims

1. A profilometer for measuring the surface profile of an object of measurement by means of causing an extremity of a probe to follow a measurement surface of the object, comprising:

a stylus having a curvature radius of 1 mm or less provided at the extremity of the probe;

curvature correction means for correcting the measurement data pertaining to the object in connection with a positional error stemming from the curvature radius of the probe;

stylus profile correction means which corrects an error in the profile of the stylus through use of profile error data pertaining to the stylus determined through measurement of an article of reference shape which is to act as a reference for calibration; and

coordinate conversion means which three-dimensionally rotates and translates said measurement data corrected by said curvature correction means and stylus profile correction means.

2. The profilometer according to claim 1,

wherein the article of reference shape employs a spherical reference ball.

3. The profilometer according to claim 2,

wherein the stylus is machined so as to have a tip-end open angle of 55°

or less and such that a tip end has a curvature radius on the order of micrometers.

4. The profilometer according to claim 1,

wherein the stylus is machined so as to have a tip-end open angle of 55°

or less and such that a tip end has a curvature radius on the order of micrometers.

5. The profilometer according to claim 4,

wherein the tip end of the stylus is made of diamond.

6. A method for measuring the surface profile of an object by means of causing a probe to follow a measurement surface of the object, wherein the probe including a stylus having a curvature radius of 1 mm or less provided at the extremity of the probe, the method comprising the steps of:

computing stylus profile error by determining a profile error caused by the curvature radius of the stylus by using measurement data of a reference ball to be used as a reference for calibration; and

correcting stylus profile by correcting measurement data of the object by using the stylus profile error.

7. The method according to claim 6,

wherein the step of correcting stylus profile includes the steps of:

correcting curvature by determining a contact position between the object and the stylus corresponding to the measurement data of the object and correcting a positional error caused by the curvature radius of the stylus by using an angle of inclination of the measurement surface of the object in the contact position; and

correcting profile error by extracting an amount of profile error in the contact position from the stylus profile error data and correcting the profile error caused by the curvature radius of the stylus by adding or subtracting the amount of the profile error.

8. A method for measuring the surface profile of an object by means of causing a probe to follow a measurement surface of the object, wherein the probe including a stylus having a curvature radius of 1 mm or less provided at the extremity of the probe, the method comprising the steps of:

computing stylus profile error by determining a profile error caused by the curvature radius of the stylus by using measurement data of a reference ball to be used as a reference for calibration; and

correcting stylus profile by correcting measurement data of the object by using the stylus profile error;

wherein the step of correcting stylus profile includes the steps of;

correcting curvature by determining a contact position between the object and the stylus corresponding to the measurement data of the object and correcting a positional error caused by the curvature radius of the stylus by using an angle of inclination of the measurement surface of the object in the contact position; and

correcting profile error by extracting an amount of profile error in the contact position from the stylus profile error data and correcting the profile error caused by the curvature radius of the stylus by adding or subtracting the amount of the profile error;

wherein the step of correcting profile error includes the steps of;

specifying a position on the reference ball at the time of measurement of the reference ball by using the angle of inclination of the measurement surface in the contact position between the stylus and the object, wherein the determined position is corresponding to the contact position of the stylus;

extracting a profile error in the specified position on the reference ball at the time of measurement of the reference ball as the amount of the profile error in the contact position of the stylus; and

correcting a profile error caused by the curvature radius of the stylus by using the extracted profile error.

9. The method according to claim 8,

wherein the amount of profile error in the contact position of the stylus is determined by interpolation based on deviation data, and

wherein the deviation data have been discretely acquired as the stylus profile error data at the time of measurement of the reference ball and pertain to a design equation.

10. The method according to claim 9,

wherein the amount of profile error in the contact position of the stylus is determined by interpolation from the discrete deviation data by using a spline curve.

11. The profilometer according to claim 10,

wherein the tip end of the stylus is made of diamond.

14. A method of manufacturing an object of measurement comprising the steps of:

detecting deviation by producing deviation data by using a design equation of the object and a profile data of the object measured by using the method as defined in any one of claims 8 through 10; and

machining for machining the profile of the object by feeding back the deviation data.

12. A method for measuring the surface profile of an object by means of causing a probe to follow a measurement surface of the object, wherein the probe including a stylus having a curvature radius of 1 mm or less provided at the extremity of the probe, the method comprising the steps of:

computing stylus profile error by determining a profile error caused by the curvature radius of the stylus by using measurement data of a reference ball to be used as a reference for calibration; and

correcting stylus profile by correcting measurement data of the object by using the stylus profile error;

wherein the step of correcting stylus profile includes the steps of;

correcting curvature by determining a contact position between the object and the stylus corresponding to the measurement data of the object and correcting a positional error caused by the curvature radius of the stylus by using an angle of inclination of the measurement surface of the object in the contact position; and

correcting profile error by extracting an amount of profile error in the contact position from the stylus profile error data and correcting the profile error caused by the curvature radius of the stylus by adding or subtracting the amount of the profile error;

wherein the amount of profile error in the contact position of the stylus is determined by interpolation based on deviation data, and

wherein the deviation data have been discretely acquired as the stylus profile error data at the time of measurement of the reference ball and pertain to the design equation.

13. The method according to claim 12,

wherein the amount of profile error in the contact position of the stylus is determined by interpolation from the discrete deviation data by using a spline curve.

15. A method of manufacturing an object of measurement comprising the steps of:

detecting deviation for producing deviation data by using a design equation of the object and a profile data of the object measured by using a method for measuring the surface profile of an object by means of causing a probe to follow a measurement surface of the object, wherein the probe including a stylus having a curvature radius of 1 mm or less provided at the extremity of the probe, the method comprising the steps of;

computing stylus profile error by determining a profile error caused by the curvature radius of the stylus by using measurement data of a reference ball to be used as a reference for calibration; and

correcting stylus profile by correcting measurement data of the object by using the stylus profile error; and

machining for machining the profile of the object by feeding back the deviation data.

16. A method of manufacturing an object of measurement comprising the steps of:

detecting deviation for producing deviation data by using a design equation of the object and a profile data of the object measured by using a method for measuring the surface profile of an object by means of causing a probe to follow a measurement surface of the object, wherein the probe including a stylus having a curvature radius of 1 mm or less provided at the extremity of the probe, the method comprising the steps of;

computing stylus profile error by determining a profile error caused by the curvature radius of the stylus by using measurement data of a reference ball to be used as a reference for calibration; and

correcting stylus profile by correcting measurement data of the object by using the stylus profile error;

wherein the step of correcting stylus profile includes the steps of;

correcting curvature by determining a contact position between the object and the stylus corresponding to the measurement data of the object and correcting a positional error caused by the curvature radius of the stylus by using an angle of inclination of the measurement surface of the object in the contact position; and

correcting profile error by extracting an amount of profile error in the contact position from the stylus profile error data and correcting the profile error caused by the curvature radius of the stylus by adding or subtracting the amount of the profile error; and

machining for machining the profile of the object by feeding back the deviation data.