Glass bumps on glass articles and methods of laser-induced growth

Abstract

A glass article having a glass bump formed integrally thereon by laser-irradiation methods. The glass bump includes a lower region connected to an upper region by an inflection region. The lower region projects from a surface of the glass article and is defined by concavely rounded sides with a radius of curvature R 1 . The upper region includes a transition portion and a top portion. The transition portion is defined by convexly rounded sides with a radius of curvature R 2 . The transition portion connects to the lower portion via the inflection region. The upper portion connects to the transition portion and is defined by a convexly rounded top surface with a radius of curvature R 3 , which is greater than radius of curvature R 2.

What is claimed is: 
     
         1 . A glass article comprising:
 a glass surface having a glass bump thereon, wherein the glass bump comprises:   a lower region comprising a diameter D 1  defined by concavely rounded sides, wherein the lower region projects from the surface of the glass article, wherein diameter D 1  is the glass bump maximum diameter, wherein the concavely rounded sides have a radius of curvature R 1  and join with the glass article surface;   an inflection region connecting the lower region of the glass bump and an upper region of the glass bump;   the upper region of the glass bump comprising a transition portion and a top portion;
 the transition portion comprising a diameter D 2  defined by convexly rounded sides, wherein the convexly rounded sides have a radius of curvature R 2 , wherein diameter D 2  is less than diameter D 1 ; and 
 the top portion comprising a diameter D 3  defined by a convexly rounded top surface, the convexly rounded top surface joining with the convexly rounded sides converging from the transition portion, wherein the convexly rounded top surface has a radius of curvature R 3  from about 900 microns to about 2600 microns which is greater than the radius of curvature R 2 , wherein diameter D 3  is less than diameter D 2 , wherein the convexly rounded top surface is spaced apart from the glass article surface defining a height H of the glass bump. 
   
     
     
         2 . The glass article of  claim 1  wherein the radius of curvature R 1  of concavely rounded sides of the lower region is from about 25 microns to about 100 microns. 
     
     
         3 . The glass article of  claim 1  wherein diameter D 1  of the lower region is from about 400 microns to about 800 microns. 
     
     
         4 . The glass article of  claim 1  wherein the radius of curvature R 2  of the convexly rounded sides of the transition portion is from about 175 microns to about 950 microns over at least 5% of the glass bump height H. 
     
     
         5 . The glass article of  claim 1  wherein diameter D 2  of the transition portion decreases from the inflection region to the top portion by about 15% to about 65%. 
     
     
         6 . The glass article of  claim 1  wherein diameter D 2  of the transition portion is from about 132 microns to about 680 microns. 
     
     
         7 . The glass article of  claim 1  wherein diameter D 3  of the top portion is from about 132 microns to about 264 microns. 
     
     
         8 . The glass article of  claim 1  wherein glass bump height H is from about 50 microns to about 200 microns. 
     
     
         9 . The glass article of  claim 1  wherein a lateral profile of the upper region has a polynomial function of the formula
     y=− 1.94×10 −8   x   4 +−5.76×10 −4   x   2 +168.47
 
 and a coefficient of determination from about 0.95 to about 0.999. 
 
     
     
         10 . The glass article of  claim 1  wherein the convexly rounded top surface of the top portion includes a concave area. 
     
     
         11 . The glass article of  claim 1  wherein the lower region is from about 5% to about 25% of glass bump height H. 
     
     
         12 . The glass article of  claim 1  wherein the upper region is from about 75% to about 95% of glass bump height H. 
     
     
         13 . The glass article of  claim 1  wherein the top portion is from about 1% to about 3% of glass bump height H. 
     
     
         14 . A glass pane including a glass bump formed on a surface of the glass pane by a method comprising:
 irradiating the glass pane surface with laser radiation converging through a lens from a laser radiation source, wherein the laser radiation converges at a distance from about 1 millimeter to about 2.5 millimeters away from the glass pane surface opposite the laser radiation source, wherein the laser radiation locally heats and induces growth of the glass bump from the glass pane, wherein the method is free of a glass bump growth-limiting structure, wherein the glass bump comprises:
 a lower region comprising a volume V 1  with a diameter D 1  defined by concavely rounded sides, wherein the lower region projects from the glass pane surface, wherein diameter D 1  is the glass bump maximum diameter, wherein the concavely rounded sides have a radius of curvature R 1  and join with the glass pane surface; 
 an inflection region connecting the lower region of the glass bump and an upper region of the glass bump; 
 the upper region comprising a volume V 2  having a transition portion and a top portion;
 the transition portion comprising a diameter D 2  defined by convexly rounded sides, wherein the convexly rounded sides have a radius of curvature R 2 , wherein diameter D 2  is less than diameter D 1 ; and 
 the top portion comprising a diameter D 3  defined by a convexly rounded top surface, the convexly rounded top surface joining with the convexly rounded sides converging from the transition portion, wherein the convexly rounded top surface has a radius of curvature R 3  from about 900 microns to about 2600 microns which is greater than the radius of curvature R 2 , wherein diameter D 3  is less than diameter D 2 , wherein the convexly rounded top surface is spaced apart from the glass pane surface defining a maximum height H of the glass bump. 
 
   
     
     
         15 . The glass pane of  claim 14  wherein volume V 1  of the lower region of the glass bump is from about 9.42×10 5  cubic microns to about 2.51×10 7  cubic microns. 
     
     
         16 . The glass pane of  claim 14  wherein volume V 2  of the upper region of the glass bump is from about 1.41×10 7  cubic microns to about 9.55×10 7  cubic microns. 
     
     
         17 . The glass pane of  claim 14  wherein volume V 2  of the glass bump is greater than volume V 1  of the glass bump. 
     
     
         18 . The glass pane of  claim 14  wherein volume V 2  of the glass bump is from about 85% to about 92% of diameter D 1 . 
     
     
         19 . The glass pane of  claim 14  wherein the radius of curvature R 3  of the convexly rounded top surface is greater than the radius of curvature R 1  for the concavely rounded sides of the lower region. 
     
     
         20 . A method of making the article of  claim 1 , wherein the article is a glass pane, the method comprising:
 irradiating the glass pane surface with laser radiation for a time to locally heat and induce growth of the glass bump from the glass pane, wherein the laser radiation is converging with a numerical aperture from about 0.01 to about 0.5 from a laser radiation source through a lens, wherein the laser radiation converges at a distance from about 1 millimeter to about 2.5 millimeters away from the glass pane surface opposite the laser irradiation source, wherein the method is free of a glass bump growth-limiting structure.