Apparatus for measuring a measurement object

• US 20030184765A1
• Filed: 03/11/2003
• Published: 10/02/2003
• Est. Priority Date: 03/13/2002
• Status: Active Grant

• Current Assignee: Werth Messtechnik GmbH
• Original Assignee: Andrea Gurny-Brosch, Eric Gurny, Patrick Gurny
• Inventors: Gurny, Werner H.
• Granted Patent: US 6,927,863 B2
• Time in Patent Office: Days
• US Class Current: 356/602
• CPC Class Codes: G01B 11/005 coordinate measuring machines
• CPC Class Codes: G01B 11/026 by measuring distance between sensor and object G01B11/0608 takes precedence
• CPC Class Codes: G01B 11/24 for measuring contours or curvatures

Abstract

An apparatus for contactlessly measuring a measurement object is proposed, which has an optical sensor, the optical sensor having an optical probe having a light source and a measurement objective for directing a light beam onto a measurement object and a receiver device for detecting a light beam reflected from the measurement object and generating a corresponding measurement signal; an advancing apparatus for altering the distance between the optical sensor and the measurement object in a first coordinate direction in a manner dependent on the measurement signal generated by the receiver device; and an evaluation unit for determining the coordinates of the measurement point on the measurement object. In order to avoid or at least reduce a so-called contouring error that occurs in conventional measurement apparatuses, the receiver device has a position-sensitive receiver which generates an evaluatable measurement signal within a programmable measurement window; the advancing apparatus sets the distance between the optical sensor and the measurement object in such a way that the receiver of the receiver device receives the light beam reflected from the measurement object within the measurement window; and the evaluation unit determines the coordinates of the measurement point on the measurement object from the position of the optical sensor and the measurement signal generated by the receiver device.

Claims

1. An apparatus for measuring a measurement object, having an optical sensor, the optical sensor having an optical probe having a light source and a measurement objective for directing a light beam onto a measurement object and a receiver device for detecting a light beam reflected from the measurement object and generating a corresponding measurement signal;

an advancing apparatus for altering the distance between the optical sensor and the measurement object in a first coordinate direction in a manner dependent on the measurement signal generated by the receiver device; and

an evaluation unit for determining the coordinates of the measurement point on the measurement object, wherein, the receiver device has a position-sensitive receiver which generates an evaluatable measurement signal within a measurement window;

the advancing apparatus sets the distance between the optical sensor and the measurement object in such a way that the receiver of the receiver device receives the light beam reflected from the measurement object within the measurement window; and

the evaluation unit determines the coordinates of the measurement point on the measurement object from the position of the optical sensor and the measurement signal generated by the receiver device.

2. The apparatus as claimed in claim 1, wherein the position-sensitive receiver of the receiver device generates a measurement signal with a linear characteristic curve within the measurement window, from which signal the evaluation unit can generate a measurement value.

3. The apparatus as claimed in claim 1, wherein the position-sensitive receiver of the receiver device is a CCD chip.

4. The apparatus as claimed in claim 1, wherein the apparatus furthermore has a control apparatus by means of which one of a plurality of operating modes of the optical sensor can be selected, wherein the operating modes are selected from the group of the following operating modes:

the distance between the optical sensor and the measurement object remains unchanged if the receiver of the receiver device receives the light beam reflected from the measurement object within the measurement window, but is continuously set in such a way that the receiver of the receiver device receives the light beam reflected from the measurement object within the measurement window (“

1^st scan mode”

),

the distance between the optical sensor and the measurement object is continuously set in such a way that the receiver of the receiver device receives the light beam reflected from the measurement object in the centroid within the measurement window (“

2^nd scan mode”

), and

the distance between the optical sensor and the measurement object is set in such a way that the receiver of the receiver device receives the light beam reflected from the measurement object within the measurement window (“

single point measurement”

).

5. The apparatus as claimed in claim 1, wherein the size of the measurement window of the receiver device is programmable.

6. The apparatus as claimed in claim 1, wherein the transmission power of the light source can be controlled in a manner dependent on the light intensity—

received by the receiver device—

of the light beam reflected from the measurement object.

7. The apparatus as claimed in claim 1, wherein the optical sensor furthermore has a video sensor for detecting measurement points on the measurement object.

8. The apparatus as claimed in claim 1 or 7, wherein the apparatus furthermore has a mechanical probe head for the mechanically probing detection of measurement points on the measurement object.

9. The apparatus as claimed in claim 1, wherein the apparatus furthermore has a machine control unit for moving the optical sensor in at least one further coordinate direction.

10. The apparatus as claimed in claim 1, wherein the apparatus furthermore has a machine control unit for moving a measurement table in at least one further coordinate direction.

11. An apparatus for measuring a measurement object, having an optical sensor, the optical sensor having an optical probe having a light source and a measurement objective for directing a light beam onto a measurement object and a receiver device for detecting a light beam reflected from the measurement object and generating a corresponding measurement signal and furthermore having a video sensor for detecting measurement points on the measurement object;

an advancing apparatus for altering the distance between the optical sensor and the measurement object in a first coordinate direction in a manner dependent on the measurement signal generated by the receiver device; and

an evaluation unit for determining the coordinates of the measurement point on the measurement object, wherein,

the receiver device has a position-sensitive receiver which generates an evaluatable measurement signal within a measurement window;

the advancing apparatus sets the distance between the optical sensor and the measurement object in such a way that the receiver of the receiver device receives the light beam reflected from the measurement object within the measurement window; and

the evaluation unit determines the coordinates of the measurement point on the measurement object from the position of the optical sensor and the measurement signal generated by the receiver device.

12. The apparatus as claimed in claim 11, wherein the optical probe and the video sensor of the optical sensor can be used either independently of one another or in combined fashion.

13. The apparatus as claimed in claim 12, wherein the video sensor is set up in the optical axis of the measurement objective on the same beam path as light source and receiver device of the optical probe for the purpose of detecting an identical measurement point on the measurement object.

14. An apparatus for measuring a measurement object, having an optical sensor, the optical sensor having an optical probe having a light source and a measurement objective for directing a light beam onto a measurement object and a receiver device for detecting a light beam reflected from the measurement object and generating a corresponding measurement signal and furthermore having a video sensor for detecting measurement points on the measurement object;

a mechanical probe head for the mechanically probing detection of measurement points on the measurement object;

an advancing apparatus for altering the distance between the optical sensor and the measurement object in a first coordinate direction in a manner dependent on the measurement signal generated by the receiver device; and

an evaluation unit for determining the coordinates of the measurement point on the measurement object, wherein,

the receiver device has a position-sensitive receiver which generates an evaluatable measurement signal within a measurement window;

the advancing apparatus sets the distance between the optical sensor and the measurement object in such a way that the receiver of the receiver device receives the light beam reflected from the measurement object within the measurement window; and

the evaluation unit determines the coordinates of the measurement point on the measurement object from the position of the optical sensor and the measurement signal generated by the receiver device.

15. The apparatus as claimed in claim 14, wherein the mechanical probe head and also the optical probe and the video sensor of the optical sensor can either be driven independently of one another or be used in a combination of two or three one after the other in any desired, alternate order.

16. The apparatus as claimed in claim 14, wherein the optical sensor and the mechanical probe head are fitted to a common center sleeve of the apparatus.

17. The apparatus as claimed in claim 14, wherein the optical sensor is fitted to a first center sleeve of the apparatus and the mechanical probe head is fitted to a second center sleeve of the apparatus, wherein the first and the second center sleeves are fitted to a common measurement slide or can be moved independently of one another.