Claims
- 1. A method for texturing a surface comprising the steps of:
- providing an element which is composed essentially of a glass material which has a thermal shock threshold fluence level above which said glass material is fractured, the element having a surface;
- concentrating pulses of laser energy selectively on a plurality of spaced-apart locations over a treatment area of said surface to alter the topography of said surface in a target area at each said spaced-apart location, each pulse of laser energy having a fluence f.sub.p at said each spaced-apart location wherein the fluence f.sub.p is less than said thermal shock threshold fluence level for said glass material;
- each pulse of laser energy having laser energy E.sub.p a duration t.sub.p and a focussed spot having a maximum spot diametral dimension D.sub.p, wherein E.sub.p, t.sub.p and D.sub.p are selected to limit said fluence f.sub.p to a value below said thermal shock threshold fluence level, whereby a bump is formed in said each target area, said each bump having a maximum bump diametral dimension D.sub.d and rising to a maximum height h.sub.d above said surface; and
- said duration t.sub.p being in the interval 10.sup.-9 to 10.sup.-1 seconds, said maximum spot diametral dimension D.sub.p >D.sub.d being in the interval 1 to 500 micrometers and said pulse of laser energy having a wavelength .lambda..sub.p such that the optical penetration of said pulse of laser energy in said surface is in the interval 10.sup.-8 to 10.sup.-3 meters.
- 2. The method of claim 1 wherein said maximum bump height h.sub.d is in the interval 1 to 1000 nanometers.
- 3. The method of claim 1 wherein said surface strongly absorbs laser energy in a first spectral region and said wavelength .lambda..sub.p is in said first spectral region and said pulses of laser energy are generated by a carbon dioxide (CO.sub.2) laser.
- 4. The method of claim 1 wherein each said spaced-apart location is separated from the nearest neighboring said spaced-apart location by a spacing distance D.sub.s .gtoreq.D.sub.d.
- 5. The method of claim 1 wherein each said spaced-apart location is separated from the nearest neighboring said spaced-apart location by a spacing distance D.sub.s substantially less than said maximum diametral dimension D.sub.d, whereby a plurality of said bumps merge with their neighboring bumps to form a substantially continuous ridge on said surface.
- 6. The method of claim 1 including the step of depositing on said surface a film of magnetic data recording material.
- 7. A method for texturing a substrate composed essentially of a glass material comprising the steps of:
- providing a substrate composed essentially of a glass material which has a thermal shock threshold fluence level above which said glass material is fractured, the substrate having a substrate surface;
- concentrating pulses of laser energy selectively on a plurality of spaced-apart locations over a treatment area of said substrate surface to alter the topography of said substrate surface in a target area at each said spaced-apart location, each pulse of laser energy having a fluence f.sub.p at said each spaced-apart location, wherein the fluence f.sub.p is less than said thermal shock threshold fluence level for said glass material; and
- each pulse of laser energy having energy E.sub.p a duration t.sub.p and a focussed spot having a maximum spot diametral dimension D.sub.p, wherein E.sub.p, t.sub.p and D.sub.p are selected to limit said fluence f.sub.p to a value below said thermal shock threshold fluence level whereby a bump is formed in said each target area, said each bump having a maximum bump diametral dimension D.sub.d and rising to a maximum height h.sub.d above said substrate surface.
- 8. A method as claimed in claim 7 wherein said substrate is composed essentially of a glass base covered with a film of magnetic data recording material.
- 9. A method as claimed in claim 7 wherein said duration t.sub.p is in the interval 10.sup.-9 to 10.sup.-1 seconds and said maximum spot diametral dimension D.sub.p >D.sub.d is in the interval 1 to 500 micrometers.
- 10. A method as claimed in claim 9 wherein said pulse of laser energy has a wavelength .lambda..sub.p such that the optical penetration of said pulse of laser energy in said glass material is in the interval [10.sup.-8, 10.sup.-3 ] meters.
- 11. A method as claimed in claim 10 wherein said substrate is composed essentially of a glass base covered with a film of magnetic data recording material.
- 12. A method as claimed in claim 7 wherein said maximum bump height h.sub.d is in the interval [1, 1000] nanometers.
- 13. A method as claimed in claim 7 wherein said pulse of laser energy has a wavelenth .lambda..sub.p such that the optical penetration of said pulse of laser energy in said glass material is in the interval [10.sup.-8, 10.sup.-3 ] meters.
- 14. A method as claimed in claim 13 wherein said glass material strongly absorbs laser energy in a first spectral region and said wavelength .lambda..sub.p is in said first spectral region.
- 15. A method as claimed in claim 14 wherein said substrate is composed essentially of a glass base covered with a film of magnetic data recording material.
- 16. A method as claimed in claim 15 wherein said duration t.sub.p is in the interval 10.sup.-9 to 10.sup.-1 seconds and said maximum spot diametral dimension D.sub.p >D.sub.d is in the interval 1 to 500 micrometers.
- 17. A method as claimed in claim 16 wherein each said spaced-apart location is separated from the nearest neighboring said spaced-apart location by a spacing distance D.sub.s .gtoreq.D.sub.d.
- 18. A method as claimed in claim 17 wherein said substrate is composed essentially of a glass base covered with a film of magnetic data recording material.
- 19. A method as claimed in claim 16 wherein each said spaced-apart location is separated from the nearest neighboring said spaced-apart location by a spacing distance D.sub.s substantially less than said maximum bump diametral dimension D.sub.d, whereby a plurality of said bumps merge with their neighboring bumps to form a substantially continuous ridge on said substrate surface.
- 20. A method as claimed in claim 19 wherein said substrate is composed essentially of a glass base covered with a film of magnetic data recording material.
- 21. A method of texturing a surface of an element comprising the steps of:
- providing a non-metallic brittle element which has a surface, the surface having a nominal surface plane;
- directing a plurality of laser pulses at a plurality of locations on the surface of the element, each laser pulse having a fluence f.sub.p and a duration t.sub.p at a respective location on the surface of the element;
- the element having a threshold thermal fluence level at each location above which the element shatters and/or results in material ejection; and each laser pulse having a fluence f.sub.p and duration t.sub.p which is selected to produce a bump of diameter D.sub.d and a height h.sub.d above said nominal surface plane at each respective location without exceeding said threshold thermal fluence level of the element at said location.
- 22. A method of texturing as claimed in claim 21 wherein:
- a plurality of bumps are formed having substantially the same height, h.sub.d ; and each bump is a smoothly shaped dome free of surface cracks and material ejection.
- 23. A method of texturing as claimed in claim 22 wherein: the height h.sub.d of each bump is from 1 to 1,000 nanometers; and the diameter D.sub.d of the bump is from 1 to 200 micrometers.
- 24. A method of texturing as claimed in claim 23 wherein each said spaced apart location is separated from a nearest neighboring spaced part location by a center to center spacing distance D.sub.s .gtoreq.D.sub.d which is from 1 to 500 micrometers.
- 25. A method of texturing as claimed in claim 24 wherein the duration t.sub.p is from 10.sup.-9 to 10.sup.-1 seconds and the laser pulse has a spot size D.sub.p at each respective location which is from 1 to 500 micrometers.
- 26. A method of texturing as claimed in claim 25 wherein the element is composed essentially of glass.
- 27. A method of texturing as claimed in claim 21 wherein:
- a plurality of laser pulses are directed at each of at least some of the locations for increasing the height of each bump at said each of at least some of the locations; and
- said plurality of laser pulses have a pulse repetition rate F.sub.p which is selected so that said threshold thermal fluence level is not exceeded at said each of at least some of the locations.
- 28. A method of texturing as claimed in claim 21 wherein the element is composed essentially of glass.
- 29. A method of texturing as claimed in claim 28 wherein:
- a plurality of laser pulses are directed at each of at least some of the locations for increasing the height of each bump at said each of at least some of the locations; and
- said plurality of laser pulses have a pulse repetition rate F.sub.p which is selected so that said threshold thermal fluence level is not exceeded at said each of at least some of the locations.
- 30. A method of texturing as claimed in claim 28 wherein: a plurality of bumps are formed having substantially the same height h.sub.d ; and each bump is a smoothly shaped dome free of surface cracks and material ejection.
- 31. A method of texturing as claimed in claim 30 wherein the element strongly absorbs laser energy in a first spectral region and the laser pulse has a wavelength .lambda..sub.p which is in said first spectral region.
- 32. A method of texturing as claimed in claim 31 wherein said laser pulse has a wavelength .lambda..sub.p which causes penetration of the laser pulse into the element at each location on the surface from 10.sup.-8 to 10.sup.-3 meters.
- 33. A method of texturing as claimed in claim 32 wherein each laser pulse causes near surface heating which melts the element at each respective location.
- 34. A method of texturing as claimed in claim 30 wherein:
- the height h.sub.d of each bump is from 1 to 1,000 nanometers; and
- the diameter D.sub.d of each bump is from 1 to 200 micrometers.
- 35. A method of texturing as claimed in claim 34 wherein the duration t.sub.p is from 10.sup.-9 to 10.sup.-1 seconds and the laser pulse has a spot size D.sub.p at each respective location which is from 1 to 500 micrometers.
- 36. A method of texturing as claimed in claim 35 wherein:
- a plurality of laser pulses are directed at each of at least some of the locations for increasing the height of each bump at said each of at least some of the locations; and
- said plurality of laser pulses have a pulse repetition rate F.sub.p which is selected so that said threshold thermal fluence level is not exceeded at said each of at least some of the locations.
- 37. A method of texturing as claimed in claim 35 wherein the element strongly absorbs laser energy in a first spectral region and the laser pulse has a wavelength .lambda..sub.p which is in said first spectral region.
- 38. A method of texturing as claimed in claim 37 wherein said laser pulse has a wavelength .lambda..sub.p which causes penetration of the laser pulse into the element at each location on the surface from 10.sup.-8 to 10.sup.-3 meters.
- 39. A method of texturing as claimed in claim 38 wherein each laser pulse causes near surface heating which melts the element at each respective location.
- 40. A method of texturing as claimed in claim 39 wherein:
- a plurality of laser pulses are directed at each of at least some of the locations for increasing the height of each bump at said each of at least some of the locations; and
- said plurality of laser pulses have a pulse repetition rate F.sub.p which is selected so that said threshold thermal fluence level is not exceeded at said each of at least some of the locations.
CROSS-REFERENCES TO RELATED APPLICATIONS
This application is a division of application No. 08/149,851, filed Nov. 10, 1993, now abandoned.
US Referenced Citations (7)
Foreign Referenced Citations (1)
Number |
Date |
Country |
43-11814 |
Nov 1992 |
JPX |
Divisions (1)
|
Number |
Date |
Country |
Parent |
149851 |
Nov 1993 |
|