Methods of cutting glass using a laser

Abstract

A method of cutting a glass article includes translating a laser beam relative to a first surface of the glass article. The laser beam includes a beam waist having a center. The center of the beam waist of the laser beam is positioned at or below a second surface of the glass article. The laser beam creates a plurality of defects along a score line in the glass article such that the plurality of defects extends a distance into the glass article, and at least some individual defects of the plurality of defects are non-orthogonal to the first surface of the glass article and are biased in a direction of translation of the laser beam. Glass articles having edge defects are also disclosed.

What is claimed is: 
     
         1 . A method of scoring a glass article having a thickness between 0.1 millimeter to 2.0 millimeters, the method comprising:
 translating a laser beam relative to a first surface of the glass article, the laser beam comprising a beam waist having a center, wherein:   the laser beam is a pulsed laser beam, said laser beam operates at a wavelength from 350 nanometers to 619 nanometers and has a pulse duration from 1 nanosecond to 50 nanoseconds;   the center of the beam waist of the laser beam is positioned at or below a second surface of the glass article such that the laser beam passes through the thickness of the glass article;   the laser beam creates a plurality of defects along a score line in the glass article such that the plurality of defects extends a distance into the glass article from the second surface; and   at least some individual defects of the plurality of defects are non-orthogonal to the first surface of the glass article and are biased in a direction of translation of the laser beam.   
     
     
         2 . The method of  claim 1 , wherein the laser beam is oriented orthogonally to the first surface of the glass article. 
     
     
         3 . The method of  claim 1 , wherein the laser beam is translated relative to the glass article at a speed S greater than about 20 millimeters per second, and the laser beam has a depth of focus between 50 microns and 1000 microns. 
     
     
         4 . The method of  claim 1 , wherein the glass article is a strengthened glass article with a thickness of not greater than 1.1 mm and, said glass article having a first strengthened surface layer and a second strengthened surface layer under a compressive stress and extending from a surface of the glass article to a depth of layer, and a central region between the first strengthened surface layer and the second strengthened surface layer that is under tensile stress wherein the central region has a tensile stress greater than 40 megapascals, and the plurality of defects extends a distance greater than the depth of layer. 
     
     
         5 . The method of  claim 4 , wherein the laser beam operates at a wavelength from 350 nanometers to 619 nanometers. 
     
     
         6 . The method of  claim 4 , wherein the strengthened glass article has a thickness is 0.7 millimeters or less, and the plurality of defects are voids and cracks. 
     
     
         7 . The method of  claim 4 , and a majority of a length of the plurality of defects is within the first or second strengthened layer. 
     
     
         8 . The method of  claim 1 , wherein the plurality of defects are voids and cracks. 
     
     
         9 . The method of  claim 1 , wherein the plurality of defects creates a crack that propagates within the glass article such that the glass article separates along the score line into one or more separated glass articles. 
     
     
         10 . The method of  claim 9 , further comprising finishing one or more edges of the one or more separated glass articles such that the one or more edges have a surface roughness below about 100 μm root mean squared. 
     
     
         11 . A method of separating a strengthened glass article comprising:
 translating a laser beam relative to a first surface of strengthened glass article, the laser beam comprising a beam waist having a center, wherein:   the laser beam is a pulsed laser beam, said laser beam operates at a wavelength from 350 nanometers to 619 nanometers and has a pulse duration from 1 nanosecond to 50 nanoseconds;   the strengthened glass article has a thickness of not greater than 1.1 mm and comprises a first strengthened surface layer and a second strengthened surface layer under a compressive stress and extending from a surface of the strengthened glass article to a depth of layer, and a central region between the first strengthened surface layer and the second strengthened surface layer that is under tensile stress;   the center of the beam waist of the laser beam is positioned at or below a second surface of the strengthened glass article such that the laser beam passes through a thickness of the strengthened glass article;   the laser beam ablates the second surface of the strengthened glass article to create a plurality of defects that extend from ablated regions on the second surface of the strengthened glass article;   the plurality of defects defines one or more score lines along the strengthened glass article;   at least a portion of the plurality of defects extends a distance greater than the depth of layer of the strengthened glass article; and   the plurality of defects creates a crack that propagates within the glass article such that the strengthened glass article separates along the one or more score lines.   
     
     
         12 . The method of  claim 11 , wherein individual defects of the plurality of defects are discrete with respect to one another prior to separation of the strengthened glass article and the crack does not propagate ahead of the laser beam in a direction of translation of the laser beam 
     
     
         13 . The method of  claim 11 , wherein at least some individual defects of the plurality of defects are non-orthogonal to the first surface of the strengthened glass article and are biased in a direction of translation of the laser beam. 
     
     
         14 . A glass article comprising:
 a first surface and a second surface separated by a thickness t that is not greater than 1.2 millimeters;   an edge joining the first surface and the second surface; and   a plurality of defects at the edge that extend from the first surface or the second surface of the glass article through a portion of the thickness t of the glass article, wherein:
 the plurality of defects extends into the thickness t of the glass article; 
 individual defects of the plurality of defects are non-orthogonal to the first surface or the second surface and the plurality of defects are voids and cracks; and 
 the individual defects of the plurality of defects are biased in a direction along the edge. 
   
     
     
         15 . The glass article of  claim 14 , wherein the plurality of defects extends into a majority of the thickness t of the glass article. 
     
     
         16 . A strengthened glass article comprising:
 a first surface and a second surface separated by a thickness t;   an edge joining the first surface and the second surface; and   a plurality of defects at the edge that extend from the first surface or the second surface of the glass article through a portion of the thickness t of the glass article, wherein:
 the plurality of defects extends into the thickness t of the glass article, and the plurality of defects comprise voids and cracks; 
 individual defects of the plurality of defects are non-orthogonal to the first surface or the second surface; and 
 the individual defects of the plurality of defects are biased in a direction along the edge, wherein the thickness t is of 0.7 mm or less, and strengthened glass article further comprises a first strengthened surface layer and a second strengthened surface layer under a compressive stress and extending from a surface of the glass article to a depth of layer, and a central region between the first strengthened surface layer and the second strengthened surface layer that is under tensile stress and the tensile stress is greater than 40 megapascals and less than 60 megapascals. 
   
     
     
         17 . The glass article of  claim 16 , wherein the distance that at least a portion of the plurality of defects extends into the glass article is greater than the depth of layer. 
     
     
         18 . The glass article of  claim 16 , wherein the strengthened glass article comprises alkali aluminosilicate glass. 
     
     
         19 . A strengthened glass article according to  claim 16  wherein said tensile stress is 45 megapascals or greater. 
     
     
         20 . A strengthened glass article according to  claim 16 , further comprising a plurality of craters on the second surface. 
     
     
         21 . A strengthened glass article according to  claim 16 , wherein the edge has a surface roughness of 100 μm root mean squared or greater.