Methods for laser processing a substrate stack having one or more transparent workpieces and a black matrix layer

Patent metadata

Field	Value
Publication number	US-11059131-B2
Application number	US-201916430985-A
Country	US
Kind code	B2
Filing date	Jun 4, 2019
Priority date	Jun 22, 2018
Publication date	Jul 13, 2021
Grant date	Jul 13, 2021

Abstract

A method for laser processing a substrate stack includes forming a defect in a transparent workpiece of the substrate stack having a black matrix layer. Forming the defect includes directing a portion of a pulsed laser beam into the transparent workpiece. The pulsed laser beam includes a wavelength λ, a spot size w o , and a Rayleigh range Z R that is greater than
F D ⁢ π ⁢ ⁢ w 0 , 2 λ ,
where F D is a dimensionless divergence factor comprising a value of 10 or greater. The pulsed laser beam directed into the transparent workpiece of the substrate stack forms a pulsed laser beam focal line disposed within the transparent workpiece, where a center of the pulsed laser beam focal line is offset from an edge of the black matrix layer by a distance that is about 20% or less of a total thickness of the substrate stack and generates an induced absorption within the transparent workpiece.

First claim

What is claimed is:

1. A method for laser processing a substrate stack, the method comprising:
forming a defect in a transparent workpiece of the substrate stack, the substrate stack further comprising a black matrix layer, wherein forming the defect comprises:
directing a portion of a pulsed laser beam into the transparent workpiece wherein the pulsed laser beam comprises:
a wavelength λ;
a spot size w o and;
a Rayleigh range Z R that is greater than

F
D

⁢

π
⁢

⁢

w

0
,

2

λ

,

where F D is a dimensionless divergence factor comprising a value of 10 or greater, wherein:
the pulsed laser beam directed into the transparent workpiece of the substrate stack forms a pulsed laser beam focal line disposed within the transparent workpiece, wherein a center of the pulsed laser beam focal line is offset from an edge of the black matrix layer by a distance that is about 20% or less of a total thickness of the substrate stack,
the pulsed laser beam focal line generates an induced absorption within the transparent workpiece, and
the pulsed laser beam focal line comprises an effective line length that is less than or equal to about 1.2 times the total thickness of the substrate stack.

2. The method of claim 1 , wherein the effective line length is less than or equal to about 1.1 times the total thickness of the substrate stack.

3. The method of claim 1 , wherein the cross-sectional edge of the pulsed laser beam focal line is offset from the edge of the black matrix layer by a distance that is about 15% or less of the total thickness of the substrate stack.

4. The method of claim 1 , wherein the pulsed laser beam is oriented along a beam pathway and output by a beam source through an aspheric optical element, through a focusing optic and the pulsed laser beam comprises an incoming beam diameter at the focusing optic such that the pulsed laser beam directed into the transparent workpiece comprises a numerical aperture of 0.05 to 0.4.

5. The method of claim 4 , wherein the aspheric optical element comprises a refractive axicon, a reflective axicon, negative axicon, a spatial light modulator, a diffractive optic, or a cubically shaped optical element.

6. The method of claim 4 , wherein the beam source produces pulse bursts with 2 sub pulses per pulse burst or greater and a pulse burst energy is from about 25 μJ to about 750 μJ per pulse burst.

7. The method of claim 1 , further comprising: translating the substrate stack and the pulsed laser beam relative to each other along a contour line, thereby laser forming a contour comprising a plurality of defects within the transparent workpiece of the substrate stack along the contour line; and directing an infrared laser beam onto the transparent workpiece of the substrate stack along or near the contour to separate the transparent workpiece along the contour.

8. The method of claim 1 , wherein the substrate stack comprises two transparent workpieces and the black matrix layer is disposed between the two transparent workpieces.

9. The method of claim 1 , wherein the transparent workpiece has combined losses due to linear absorption and scattering less than 20%/mm in a beam propagation direction.

10. The method of claim 1 , wherein spacing between adjacent defects is about 25 μm or less.

11. A method for laser processing a substrate stack, the method comprising:
forming a defect in a transparent workpiece of the substrate stack, the substrate stack further comprising a black matrix layer, wherein forming the defect comprises:
directing a pulsed laser beam oriented along a beam pathway and output by a beam source through an aspheric optical element, through a focusing optic, and into the substrate stack such that the pulsed laser beam directed into the transparent workpiece of the substrate stack forms a pulsed laser beam focal line disposed within the transparent workpiece, wherein:
a center of the pulsed laser beam focal line is offset from an edge of the black matrix layer by a distance that is about 20% or less of a total thickness of the substrate stack,
the pulsed laser beam focal line generates an induced absorption within the transparent workpiece, and
the pulsed laser beam directed into the transparent workpiece comprises a numerical aperture of 0.05 to 0.4.

12. The method of claim 11 , wherein the cross-sectional edge of the pulsed laser beam focal line is offset from the edge of the black matrix layer by a distance that is about 15% or less of the total thickness of the substrate stack.

13. The method of claim 11 , wherein the pulsed laser beam focal line comprises an effective focal line length that is less than or equal to about 1.2 times the total thickness of the substrate stack.

14. The method of claim 11 , further comprising translating the substrate stack and the pulsed laser beam relative to each other along a contour line, thereby laser forming a contour comprising a plurality of defects within the transparent workpiece of the substrate stack along the contour line.

15. The method of claim 11 , wherein the pulsed laser beam comprises an incoming beam diameter at the focusing optic such that the pulsed laser beam directed into the transparent workpiece comprises a numerical aperture of 0.01 to 0.4.

16. The method of claim 11 , wherein the beam source produces pulse bursts with 2 sub pulses per pulse burst or greater and a pulse burst energy is from 25 μJ to 750 μJ per pulse burst.

17. The method of claim 11 , wherein a portion of the pulsed laser beam directed into the transparent workpiece comprises:
a wavelength λ;
a spot size w o ; and
a Rayleigh range Z R that is greater than

F
D

⁢

π
⁢

⁢

w

0
,

2

λ

,

 where F D is a dimensionless divergence factor comprising a value of 10 or greater.

18. A glass article comprising:
a glass substrate having an edge defining a perimeter of the glass substrate;
a black matrix layer disposed on the glass substrate;
a plurality of vertical striations formed on the edge of the glass substrate, wherein:
the plurality of vertical striations include a pitch of about 50 microns or less and extend through at least 50% of a thickness of the glass substrate and
the black matrix layer is offset by a distance from the edge of the glass substrate by about 20% or less a total

Assignees

• Corning Inc

Inventors

• Piech Garrett Andrew
• Wieland Kristopher Allen

Classifications

• C03B33/076 Primary

  Laminated glass comprising interlayers · CPC title

• B23K26/53

  for modifying or reforming the material inside the workpiece, e.g. for producing break initiation cracks · CPC title

• B23K2103/54

  Glass · CPC title

• B23K26/066

  by using masks · CPC title

• B23K26/364 Primary

  for making a groove or trench, e.g. for scribing a break initiation groove · CPC title