Method for Internal Laser Marking in Transparent Materials and Device for Implementing Said Method

• US 20080304525A1
• Filed: 09/22/2006
• Published: 12/11/2008
• Est. Priority Date: 09/22/2005
• Status: Abandoned Application

• Current Assignee: Trackinside, Societe Anonyme
• Original Assignee: Trackinside, Societe Anonyme
• Inventors: Mottay, Eric, Kupisiewicz, Axel
• Application Number:
  US11/992,299
• Publication Number:
  US 20080304525A1
• Time in Patent Office: Days
• US Class Current: 372/30
• CPC Class Codes: B41M 5/262 recording or marking of inorganic surfaces or materials, e.g. glass, metal, or ceramics marking of plastic artifacts with inorganic additives B41M5/267
• CPC Class Codes: C03C 23/0025 by a laser beam

Abstract

The invention concerns a method for internal laser marking in transparent materials, for example for marking an identifier (5) for an object made of transparent material (6). The invention is characterized in that a diode-pumped femtosecond laser source (1) is used for non-aggressive high-contrast marking to generate laser pulses (13) which are successively focused on different points (23) of the marking (5) to be produced and enabling high-speed marking operations, typically faster than 0.1 mm2 per second to be performed.

Claims

1. Internal laser marking method for transparent materials, comprising using a diode-pumped femtosecond laser source to generate laser pulses that are successively focused in different points of an area of the transparent material to be marked for creating a non-aggressive high-contrast marking.

2. Method according to claim 1, wherein the used laser source enables a marking speed of more than 1 mm² per second.

3. Method according to claim 1, including using an Ytterbium-doped crystal in the diode-pumped femtosecond laser.

4. Method according to claim 1, wherein the diode-pumped femtosecond laser is a fiber laser.

5. Method according to claim 1, wherein the diode-pumped femtosecond laser is a femtosecond oscillator.

6. Method according to claim 1, wherein the diode-pumped femtosecond laser is a femtosecond amplifier.

7. Method according to claim 1, wherein the diode-pumped femtosecond laser is a regenerative femtosecond amplifier.

8. Method according to claim 1, wherein the diode-pumped femtosecond laser is a regenerative femtosecond amplifier and does not use any chirped pulse amplification.

9. Method according to claim 1, wherein the diode-pumped femtosecond laser has a repetition rate of more than 10 kHz.

10. Method according to claim 1, wherein the diode-pumped femtosecond laser has a pulse length of less than 3 ps.

11. Method according to claim 1, wherein the diode-pumped femtosecond laser has an energy per pulse of more than 3 μ

J.

12. Method according to claim 1, wherein the marking is so small so as to be invisible to the naked eye.

13. Method according to claim 1, wherein the marking is readable by means of a standard reading system or viewing system.

14. Method according to claim 1, wherein the marking is smaller than 60×

60 μ

m.

15. Method according to claim 1, wherein the marking is engraved in less than 0.05 seconds.

16. Method according to claim 1, wherein the marking is made in less than 0.2 seconds.

17. Method according to claim 1, wherein the marking has contrast of 70% (grade A—

AIM).

18. Method according to claim 1, wherein the femtosecond laser pulse creates a local modification of the refraction index of the transparent material.

19. Method according to claim 18, wherein the index modulations created by the method have a strongly varying amplitude in a longitudinal direction, namely in the direction of propagation of the laser pulses.

20. Method according to claim 1, including filling of the marking with a diffractive structure.

21. Method according to claim 1, including filling the marking with repetitive forms or patterns.

22. Method according to claim 1, wherein the marking is filled with lines or dots that are mutually separated by a distance in the order of the wavelength spectrum of a reader.

23. Method according to claim 1, wherein the marking comprises a normative part and an antifraud part.

24. Method according to claim 1, wherein the marking comprises a decorative design.

25. Method according to claim 1, wherein the marking is an identification code, and a few bits of the identification codes define the position of an invisible antifraud code.

26. Method according to claim 1, wherein the transparent material is glass and the marking is formed on the inside of the glass material.

27. Method according to claim 1, wherein the transparent material is glass flasks and the marking is marked inside the flasks.

28. Method according to claim 1, wherein the transparent material is perfume bottles and the marking is marked inside the perfume bottles.

29. Method according to claim 1, wherein the transparent material is car windows and the marking is formed in the car window.

30. Method according to claim 1, wherein the transparent material is a tempered glass pane, and the marking is formed in the tempered glass pane.

31. Method according to claim 1, wherein the marking is integrated so as to form an integral part of a trade name or a registered trade mark.

32. Method according to claim 1, wherein more than one marking is provided next to another one, but at different depths.

33. Method according to claim 1, wherein the visual angle from where the identifier can be read can be clearly modified so as to further increase the security.

34. Method according to claim 1, wherein the identifier is provided inside a data carrier or inside a packaging for the data carrier.

38. Code comprising a marking made according to the method of claim 1 for preventing counterfeiting.

39. Code comprising a marking made according to the method of claim 1, for controlling distribution circuits.

35. Device for the internal marking of transparent materials, comprising a diode-pumped femtosecond laser comprising a regenerative femtosecond laser and which does not use any chirped pulse amplification;

a galvanometric head;

focusing optics and a control system.

36. Device according to claim 35, wherein the laser is a diode-pumped femtosecond laser with a repetition rate of more than 10 kHz and pulse energies comprised between 1 and 100 μ

J.

37. Device according to claim 36, including a viewing system for verifying the marking information and an appropriate light.