Reducing diffraction effects on an ablated surface

• US 9,703,166 B2
• Filed: 10/23/2015
• Issued: 07/11/2017
• Est. Priority Date: 10/24/2014
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Bareman, Donald L., Scott, Thomas J., Olesen, Niels A., Luten, Henry A., Geerlings, Kurtis L., Tonar, William L.
• Primary Examiner(s): TRA, TUYEN Q
• Application Number:
  US14/922,047
• Publication Number:
  US 20160114523A1
• Time in Patent Office: 627 Days
• Field of Search: 359265-275, 359900, 359896, 264 11, 264 134, 264 27
• CPC Class Codes: B23K 26/048 by controlling the distance between laser head and workpiece
• CPC Class Codes: B23K 26/355 Texturing
• CPC Class Codes: B23K 26/361 for deburring or mechanical trimming B23K26/351 takes precedence
• CPC Class Codes: B23K 26/362 Laser etching
• CPC Class Codes: B23K 26/57 the laser beam entering a face of the workpiece from which it is transmitted through the workpiece material to work on a different workpiece face, e.g. for effecting removal, fusion splicing, modifying or reforming
• CPC Class Codes: G02F 1/1533 structural features not otherwise provided for

Abstract

A method is provided for laser ablation that reduces or eliminates a diffraction effect produced by damage to a surface from which an ablated material is removed. The method includes at least one of reducing the amount of surface damage produced and altering the damage structure produced such that it is irregular.

Claims

1. A method of removing a material from a surface, comprising:

passing a laser through a lens such that the laser impinges on the material, and

wherein a working distance between the lens and the material is different than a focal length of the lens such that a focal plane of the laser is located beyond the surface in a direction of propagation of the laser.

2. The method of claim 1, wherein the working distance is less than 95% of the focal length.

3. The method of claim 1, wherein the surface from which the material is removed does not exhibit an objectionable diffraction effect after the material has been removed.

4. The method of claim 1, wherein the surface from which the material is removed exhibits a diffraction severity of less than 5 after the material has been removed.

5. The method of claim 1, wherein the surface from which the material is removed exhibits a periodic structure after the material has been removed.

6. The method of claim 1, wherein the laser passes through the surface before the laser impinges on the material to be removed.

7. An electrochromic assembly comprising an element produced according to the method of claim 1.

8. A method of removing a material from a surface, comprising:

passing a laser through a lens such that the laser impinges on the material, and

wherein the surface from which the material is removed has an array of artifacts thereon with a spacing between artifacts and a pitch between lines of artifacts, and wherein at least the pitch is varied.

9. The method of claim 8, wherein at least one of the spacing and pitch is random or pseudo-random.

10. The method of claim 8, wherein the pitch is between 60 μ

m and 200 μ

m.

11. The method of claim 8, wherein the artifacts each have a characteristic radii, and at least a portion of the artifacts have different characteristic radii.

12. The method of claim 8, wherein a working distance between the lens and the material is different than a focal length of the lens.

13. The method of claim 8, further comprising varying a pulse frequency of the laser, such that a variation in the spacing of pulses incident on the material is produced.

14. The method of claim 8, further comprising varying a scan speed of the laser over the material, such that a variation in the spacing of laser pulses incident on the material is produced.

15. The method of claim 8, wherein the lens is a variable lens, and further comprising modulating the focal length of the lens.

16. The method of claim 8, further comprising driving an actuated mirror located along a beam path of the laser, such that a variation in a spacing of laser pulses incident on the material is produced.

17. The method of claim 8, wherein the surface from which the material is removed does not exhibit an objectionable diffraction effect after the material has been removed.

18. The method of claim 8, wherein the surface from which the material is removed exhibits a diffraction severity of less than 5 after the material has been removed.

19. The method of claim 8, wherein the laser passes through the surface before the laser impinges on the material to be removed.

20. An electrochromic assembly comprising an element produced according to the method of claim 8.