Transparent material processing with an ultrashort pulse laser

Patent metadata

Field	Value
Publication number	US-9636773-B2
Application number	US-201313766357-A
Country	US
Kind code	B2
Filing date	Feb 13, 2013
Priority date	Sep 8, 2005
Publication date	May 2, 2017
Grant date	May 2, 2017

Abstract

A method for scribing transparent materials uses ultrashort laser pulses to create multiple scribe features with a single pass of the laser beam across the material, with at least one of the scribe features being formed below the surface of the material. This enables clean breaking of transparent materials at a higher speed than conventional techniques.

First claim

What is claimed is:

1. A method of scribing a transparent material, comprising:
using a single pass of a focused beam of ultrashort laser pulses to create a surface groove in said material and at least one modified region within the bulk of said material during motion of said transparent material relative to said focused laser beam,
wherein an intensity of said focused beam produces non-linear absorption within a material region, and said ultrashort pulses are generated at a repetition rate sufficiently high such that spatial overlap between said pulses, and interaction between said laser pulses and a modified region, creates at least one additional region of material modification within the material,
wherein said surface groove and said at least one modified region are each formed by interaction of said focused beam with said material, said surface groove in said material and said at least one modified region within the bulk being formed along a beam propagation direction, and
wherein said surface groove and said at least one modified region are discontinuous and separated in depth.

2. The method according to claim 1 , wherein a location of said surface groove and said at least one modified region are separated by a determined distance.

3. The method according to claim 1 , wherein said transparent material comprises sapphire.

4. A method for scribing a transparent material, comprising:
using a single pass of a focused beam of ultrashort laser pulses to create a plurality of modified regions within the bulk of said material during motion of said transparent material relative to the focused laser beam, wherein said method comprises focusing said beam within the bulk of said material such that an intensity of said focused beam produces non-linear absorption within said material and causes first material modification at a first location within said material in the beam propagation direction and second material modification at a second location at a greater distance along said beam propagation direction within said material,
wherein each of said first and second material modifications are formed along said beam propagation direction as discontinuous regions separated in depth,
wherein said beam of ultrashort pulses is generated at a repetition rate sufficiently high such that said first and second material modifications are formed with spatially overlapping pulses during said single pass.

5. The method according to claim 4 , wherein said first location is at or near the surface of the material.

6. A transparent material scribed at two or more locations in a depth direction thereof with a single pass of a focused beam of ultrashort laser pulses,
wherein said scribed locations comprise a surface groove scribed in said material and at least one scribe feature formed in the bulk of said material,
wherein said surface groove and said at least one scribe feature are formed along said beam propagation direction, said surface groove and said at least one scribe feature being discontinuous and separated in depth, and
wherein a location of said surface groove and said at least one scribe feature are separated by a determined distance.

7. A method of scribing a transparent material, comprising:
irradiating said material with a beam of focused and spatially overlapping ultrashort laser pulses, in a single pass and during motion of said transparent material relative to said focused laser beam, to modify said material at two or more locations and produce scribe features in a depthwise direction thereof, wherein an intensity of said focused beam produces non-linear absorption within a material region,
wherein at least a portion of said irradiating is carried out with a diffractive optical element that generates multiple regions of high optical intensity at different depthwise locations along a propagation axis of said focused laser beam, said diffractive optical element receiving an input beam and generating multiple laser modified discontinuous regions separated in depth.

8. The method of claim 7 , wherein a surface groove is formed in said material, and at least one modified region is formed within the bulk of said material.

9. A method of scribing a transparent material, comprising:
generating a zero-th order Bessel beam of laser light, and
irradiating said material in a single pass with said beam during motion of said transparent material relative to the beam to modify said material at two or more locations in a depthwise direction thereof using multiple regions of high optical intensity generated by said beam at different depthwise locations within said material,
wherein an intensity of said beam produces non-linear absorption within said material.

10. The method according to claim 9 , wherein a surface groove is formed in said material, and at least one modified region is formed within the bulk of said material.

11. A system for scribing a transparent material, comprising:
an ultrashort laser source to generate a beam of ultrashort laser pulses, wherein said beam of ultrashort pulses comprises a pulse duration in the range from 50 fs to 500 ps;
an optical system to focus and deliver said beam of ultrashort laser pulses to said material with optical intensity sufficiently high so as to produce non-linear absorption within said material, and to modify said material at two or more locations in a depthwise direction thereof so as to produce scribe features; and
a motion system to produce motion of said transparent material relative to said focused laser beam, said motion system operatively connected to said ultrashort laser source and said optical system,
wherein said ultrashort laser source and said motion system are configured in such a way that said ultrashort pulses are generated at a repetition rate sufficiently high such that said-material modifications and scribe features are simultaneously formed with spatially overlapping pulses during said motion and in a single pass of said laser beam with respect to said material.

12. The system for scribing a transparent material according to claim 11 , wherein said optical system produces a focused beam waist in the bulk of said material such that ablation or material modification occurs simultaneously at said beam waist position and at one or more material locations between said beam waist and said optical system.

13. The system for scribing a transparent material according to claim 11 , wherein said one or more material locations are in the bulk of said material.

14. The system for scribing a transparent material according to claim 11 , wherein said one or more material locations comprise a surface of said material, and said ablation or material modification forms a groove in said surface.

15. The system for scribing a transparent material according to claim 11 , wherein an interaction between said laser pulses and a modified region creates at least one additional region of material modification within the material.

Assignees

• Imra America Inc

Inventors

• Bovatsek James
• Arai Alan Y
• Yoshino Fumiyo

Classifications

• B29C65/1635

  at least passing through one of the parts to be joined, i.e. laser transmission welding · CPC title

• B29C66/949

  characterised by specific time values or ranges · CPC title

• B23K26/244

  Overlap seam welding · CPC title

• B29C66/73366

  both parts to be joined being transparent or translucent to visible light · CPC title

• B29C66/3282

  for reinforcing the joint · CPC title