SCAN HEAD CALIBRATION SYSTEM AND METHOD

• US 20100292947A1
• Filed: 10/17/2008
• Published: 11/18/2010
• Est. Priority Date: 10/23/2007
• Status: Abandoned Application

• Current Assignee: Coherent Singapore Pte Ltd. (Coherent Corp.)
• Original Assignee: Hypertronics Corporation (Smiths Group International Holdings Ltd.)
• Inventors: Buk, Mum Fatt
• Application Number:
  US12/739,385
• Publication Number:
  US 20100292947A1
• Time in Patent Office: Days
• US Class Current: 702/94
• CPC Class Codes: B23K 26/042 Automatically aligning the laser beam
• CPC Class Codes: B23K 26/082 Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head
• CPC Class Codes: G01B 11/03 by measuring coordinates of points
• CPC Class Codes: G01B 21/042 Calibration or calibration artifacts G01B3/30, G01B9/02072 take precedence

Abstract

A method and system are provided for reducing a positioning error for positioning a light beam either onto or from a workpiece. A calibration mark is provided, and an image of the calibration mark is captured, to compare with a guide mark. The position of the guide mark corresponds to a set of design data or coordinates. The position of the image of the calibration mark is adjusted until the image matches with the guide mark. A set of vision compensating factors can therefore be determined. Thereafter, an image of a laser mark is captured, and adjusted to match the guide mark, to determine a set of scan head compensating factors. The design data can then be modified based on the vision compensating factors and the laser compensating factors, and used to position the laser beam onto the workpiece or capture light from a work piece to form an image.

Claims

1. A method of reducing a positioning error in a laser processing system for positioning a laser beam onto a workpiece, comprising:

providing a calibration mark;

providing a guide mark corresponding to a set of design data;

matching an image of the calibration mark to the guide mark to determine a set of vision compensating, factors;

matching an image of a laser, mark to the guide mark to determine a set of laser compensating factors; and

modifying the set of design data to position the laser beam onto the workpiece using the set of vision compensating factors and the set of laser compensating factors.

2. The method of claim 1, wherein matching the image of the calibration mark to the guide mark further comprises:

fixing a vision assembly along a first vision path based on the set of design data;

obtaining the image of the calibration mark through the vision assembly along the first vision path;

varying the first vision path to a second vision path to bring the image of the calibration mark into alignment with the guide mark, wherein the second vision path corresponds to a set of modified design data; and

determining the set of vision compensating factors from the set of design data and the modified data.

3. The method of claim 1, wherein the calibration mark is a first calibration mark corresponding to a border of a rectangle processing field, wherein the method further comprises providing a plurality of calibration marks corresponding to an opposite border, adjacent borders and corner areas of the rectangle processing field.

4. The method of claim 3, wherein the guide mark is a first guide mark corresponding to the first calibration mark, wherein the method further comprises providing a plurality of guide marks each corresponding to one of the plurality of calibration marks.

5. The method of claim 4, wherein matching each of the plurality of calibration marks to a corresponding one of the plurality of guide marks at opposite borders determines a first vision proportional factor along a first direction, and a second vision proportional factor along a second direction substantially orthogonal to the first direction.

6. The method of claim 4, further comprising determining a distortion factor of a corner area from matching each of the plurality of calibration marks at the corner area to a corresponding one of the plurality of guide marks at the corner area.

7. The method of claim 4, wherein the plurality of guide marks are distributed through a two-dimensional scan-vision field.

8. The method of claim 7, wherein the plurality of guide marks define a full scan-vision field.

9. The method of claim 7, wherein the plurality of guide marks define a half scan-vision field.

10. The method of claim 1, wherein matching the image of the laser mark to the guide mark further comprises:

fixing a laser assembly along a first laser path based on the set of design data;

creating the laser mark;

obtaining the image of the laser mark along the first laser path;

varying the first laser path to a second laser path to bring the image of the laser mark into alignment with the guide mark wherein the second laser path corresponds to a second set of data; and

determining the set of laser compensating factors from the first and second sets of data.

11. The method of claim 10, wherein the laser mark is a first laser mark corresponding to a border of a rectangle processing field, wherein the method further comprises providing a plurality of laser marks corresponding to an opposite border and adjacent borders of the processing field.

12. The method of claim 11, wherein the guide mark is a first guide mark corresponding to the first laser mark, wherein the method further comprises providing a plurality of guide marks each corresponding to one of the plurality of laser marks.

13. The method of claim 12, wherein matching each of the plurality of laser marks to a corresponding one of the plurality of guide marks at opposite borders determines a first laser proportional factor along a first direction and a second laser proportional factor along a second direction substantially orthogonal to the first direction.

14. A method for directing a laser beam onto a workpiece at a predetermined location, the method comprising:

providing a set of design data defining the predetermined location;

providing a guide mark corresponding to the set of design data;

providing a calibration mark;

matching an image of the calibration mark to the guide mark to determine a set of vision compensating factors;

introducing the set of vision compensating factors to the set of design data to generate a set of modified data; and

directing the laser beam onto the workpiece based on the modified data.

15. The method of claim 14, wherein the set of compensating factors includes a set of vision compensating factors and a set of laser compensating factors.

16. The method of claim 15, wherein the set of vision compensating factors is obtained by matching an image of a calibration mark to a guide mark.

17. The method of claim 16, wherein the set of laser compensating factors is obtained by matching an image of a laser calibration mark to the guide mark.

18. An apparatus for reducing a positional error of a laser processing system having a laser assembly and a vision assembly, the apparatus comprising:

a calibration jig having a calibration mark; and

a guide mark provided in the vision assembly wherein the vision assembly is fixable along a first vision path based on a set of design coordinate data to capture an image of the calibration mark, wherein the first vision path is variable to a second vision path based on a set of modified coordinate data to match the image of the calibration mark to the guide mark, and wherein the set of design data and the set of modified data are to determine a vision compensating factor for reducing the positional error.

19. The apparatus of claim 18, wherein the calibration mark is a first calibration mark corresponding to a border of a rectangle processing field, wherein the calibration jig further comprises a plurality of additional calibration marks corresponding to an opposite border, adjacent borders and corner areas of the processing field.

20. The apparatus of claim 19, wherein the guide mark is a first guide mark corresponding to the first calibration mark, wherein the apparatus further comprises a plurality of additional guide marks each corresponding to one of the plurality of additional calibration marks.

21. A method for calibrating a scan vision system, comprising:

providing a calibration mark;

providing a guide mark corresponding to a set of design data;

matching an image of the calibration mark to the guide mark to determine a set of vision compensating factors;

modifying the set of design data using the set of vision compensating factors to generate a set of modified design data; and

calibrating the scan vision system based on the modified design data.

22. The method of claim 21, wherein matching the image of the calibration mark to the guide mark further comprises:

fixing the scan vision system along a first vision path based on the set of design data;

obtaining the image of the calibration mark along the first vision path;

varying the first vision path to a second vision path to align the image of the calibration mark with the guide mark wherein the second vision path corresponds to a set of modified data; and

wherein determining the set of vision compensating factors from the set of design data and the modified data.

23. The method of claim 21, wherein the calibration mark is a first calibration mark corresponding to a border of a rectangle processing field;

wherein the method further comprises providing a plurality of calibration marks corresponding to an opposite border, adjacent borders and corner areas of the processing field.

24. The method of claim 23, wherein the guide mark is a first guide mark corresponding to the first calibration mark, wherein the method further comprises providing a plurality of guide marks each corresponding to one of the plurality of calibration marks.

25. The method of claim 24, wherein matching each of the plurality of calibration marks to a corresponding one of the plurality of guide marks at opposite borders determines a first vision proportional factor along a first direction, and a second vision proportional factor along a second direction substantially orthogonal to the first direction.

26. The method of claim 24, wherein matching one of the plurality of calibration marks to a corresponding one of the plurality of guide marks at a corner area determines a distortion factor of said corner area.

27. The method of claim 24, wherein the plurality of guide marks are distributed through a two-dimensional scan-vision field.

28. The method of claim 27, wherein the plurality of guide marks define a full scan-vision field.

29. The method of claim 27, wherein the plurality of guide marks define a half scan-vision field.