Contact type shape measuring apparatus

• US 9,016,106 B2
• Filed: 11/09/2011
• Issued: 04/28/2015
• Est. Priority Date: 11/24/2010
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Miyata, Akinori
• Primary Examiner(s): Williams, Hezron E
• Assistant Examiner(s): FAYYAZ, NASHMIYA SAQIB
• Application Number:
  US13/292,838
• Publication Number:
  US 20120125088A1
• Time in Patent Office: 1,266 Days
• Field of Search: 731/04, 73/17.9, 73/18.1
• US Class Current: 73/1.79
• CPC Class Codes: G01B 21/045 Correction of measurements G01B9/02055 takes precedence
• CPC Class Codes: G01B 5/008 using coordinate measuring machines

Abstract

An acting force is applied to a probe on the basis of a target speed serving as a probe speed in a stable copy scanning state of a target surface to be measured and a probe speed error serving as a difference between the target speed and a probe speed.

Claims

1. A shape measuring apparatus comprising:

a moving member configured to move three-dimensionally;

a probe supported movably relative to the moving member;

a position measuring unit configured to measure a position of the probe;

a probe-speed calculation unit configured to calculate a probe speed serving as speed information in a moving direction of the probe on the basis of position information about the position of the probe obtained by the position measuring unit;

a target-speed calculation unit configured to calculate a probe target speed with reference to probe speed information of the probe scanning a target object to be measured;

an acting-force calculation unit configured to calculate an acting force that reduces a probe speed error serving as a difference between the probe target speed and the probe speed on the basis of the probe speed error; and

a force generating unit configured to generate, in the probe, an acting force of a component in the moving direction of the probe in accordance with the calculated acting force;

wherein the shape measuring apparatus measures a shape of the target object by scanning a surface of the target object and measuring the position of the probe while the probe is in contact with the target object,

wherein the target-speed calculation unit sets the target speed whether a relative displacement between the moving member and the probe is within a threshold value or not,

wherein if the relative displacement is within the threshold value, the target-speed calculation unit sets the target speed with reference to a current probe speed, and

wherein if the relative displacement exceeds the threshold value, the target-speed calculation unit sets the target speed with reference to past speed information of the probe.

2. The shape measuring apparatus according to claim 1, wherein the acting-force calculation unit calculates the acting force by multiplying the probe speed error by a proportionality coefficient when the probe speed error exceeds a threshold value.

3. The shape measuring apparatus according to claim 1, wherein the acting-force calculation unit calculates a fixed acting force when the probe speed error exceeds a threshold value.