Laser marking

• US 7,005,603 B2
• Filed: 04/02/2004
• Issued: 02/28/2006
• Est. Priority Date: 04/02/2004
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Addington, Cary G., Huynh, Quoc, Hubley, Timothy S.
• Primary Examiner(s): Heinrich, Samuel M.
• Application Number:
  US10/817,134
• Publication Number:
  US 20050224578A1
• Time in Patent Office: 697 Days
• Field of Search: 219/121.6, 219/121.61, 219/121.62, 219/121.65, 219/121.66, 219/121.68, 219/121.69, 219/121.76, 219/121.77, 219/121.85
• US Class Current: 219/121.69
• CPC Class Codes: B41M 5/267 Marking of plastic artifacts, e.g. with laser
• CPC Class Codes: G09F 3/00 Labels, tag tickets, or similar identification or indication means medals or badges A44C3/00; making labels B31D1/02; sheets temporarily attached together B42F; labelling B65C; labels on record carriers G11B23/38, G11B23/40; Seals; Postage or like stamps

Abstract

A method for marking a polymeric surface includes directing a first laser beam on the surface to form a lightened area on the surface and directing a second laser beam upon the lightened area to form a mark darker than the lightened area.

Claims

1. A method for marking a polymeric surface, the method comprising:

directing a first laser beam to form a lightened area on a surface; and

directing a second laser beam upon the lightened area to form a first mark darker than the lightened area.

2. The method of claim 1 including burning a portion of the lightened area with the second laser beam to form the first mark.

3. The method of claim 1 including removing a portion of the lightened area with the second laser beam to expose raw polymeric material to form the first mark.

4. The method of claim 1, wherein the first laser beam has a first energy density and wherein the second laser beam has a second greater energy density.

5. The method of claim 1, wherein the first laser beam is moved across the surface at a first speed and wherein the second laser beam is moved across the lightened area at a second slower speed.

6. The method of claim 1, wherein the surface is moved relative to the first laser beam at a first speed and wherein the lightened area is moved relative to the second laser beam at a second slower speed.

7. The method of claim 1, wherein the first laser beam has a first duty cycle and wherein the second laser beam has a second greater duty cycle.

8. The method of claim 1 including directing the second laser beam upon the lightened area to form a second mark darker than the lightened area and spaced from the first mark.

9. The method of claim 8, wherein the first mark and the second mark are configured to be read by an optical scanning device.

10. The method of claim 8, wherein the first mark and the second mark are configured to be part of an identification matrix.

11. The method of claim 1, wherein the first mark is configured to be read by an optical scanning device.

12. The method of claim 1, wherein the first laser beam is configured to vaporize at least one additive along the surface.

13. The method of claim 1, wherein the at least one material includes carbon black.

14. The method of claim 1, wherein the surface is a polymeric material including carbon black.

15. The method of claim 1, wherein the first mark is contained within a total mark area and wherein the lightened area extends at least six pixels beyond the total mark area.

16. The method of claim 1, wherein the first laser beam is produced by a Q-switched Nd:

YAG laser having a 1064 nanometer wavelength.

17. The method of claim 16, wherein the laser beam has a duty cycle of between about 10 kilohertz and about 100 kilohertz, a power of between about 1 watt and 50 watts and a scan speed of between about 100 millimeters per second and about 4,000 millimeters per second.

18. The method of claim 16, wherein the first laser beam has a first frequency of 60 kilohertz, a first power of 4.38 watts and a first scan speed of 1,500 millimeters per second and wherein the second laser beam has a second frequency of 60 kilohertz, a second power of 4.38 watts and a second scan speed of about 350 millimeters per second.

19. The method of claim 1, wherein the first laser beam has a wavelength of between about 1,000 nanometers and about 1,500 nanometers.

20. The method of claim 1, wherein the first laser beam is produced by a carbon dioxide laser having a wavelength of between about 9.2 micrometers and about 10.6 micrometers.

21. The method of claim 1, wherein the first laser beam and the second laser beam is generated by a common laser.

22. The method of claim 21, wherein the first laser beam has a first power and wherein the second laser beam has a second greater power.

23. A method for identifying parts having a polymeric surface, the method comprising:

directing a first laser beam on the surface to form a lightened area on the surface;

directing a second laser beam upon the lightened area to form a first mark darker than the lightened area;

moving at least one of the part and an optical scanner relative to one another, wherein the scanner produces signals based upon the first mark; and

identifying the part based at least partially upon the signals produced by the optical scanner.

24. A method for identifying a part having a polymeric surface, the method comprising:

scanning a first mark formed on the polymeric surface by a first laser beam and a surrounding lightened area formed on the surface with a second laser beam.