Apparatus and method for edge processing of glass for light coupling

Abstract

Methods and apparatus for finishing an edge of a glass sheet are described. The edge of the glass sheet is finished using two grinding wheels mounted on spindles so that the edge of the grinding wheels chamfer the edge of the glass sheet during relative movement of the grinding wheels and the glass sheet.

1 . An apparatus for finishing an edge of a glass sheet, the apparatus comprising:
 a worktable which supports the glass sheet while the edges are subjected to grinding and polishing, wherein an X-axis is a direction of lateral movement on a plane of a glass sheet on the worktable, a Y-axis is a direction of longitudinal movement on the plane which is perpendicular to the X-axis, and a Z-axis is a direction of orthogonal movement with respect to the plane;   a first motor with a first spindle having a first spindle axis of rotation positioned on a first side of the plane, the first spindle axis aligned substantially along the X-axis;   a second motor with a second spindle having a second spindle axis of rotation positioned on a second side of the plane, the second spindle axis aligned substantially along the X-axis;   a first grinding wheel mounted on the first spindle, the first grinding wheel substantially disc-shaped with a peripheral edge to chamfer a first edge of the glass sheet using the peripheral edge of the first grinding wheel; and   a second grinding wheel mounted on the second spindle, the second grinding wheel substantially disc-shaped with a peripheral edge to chamfer a second edge of the glass sheet using the peripheral edge of the second grinding wheel.   
     
     
         2 . The apparatus of  claim 1 , wherein one or more of the first spindle or the second spindle further comprises an additional grinding wheel. 
     
     
         3 . The apparatus of  claim 1 , wherein the first spindle and the second spindle are configured to create a chamfer of less than or equal to about 5% of a thickness of the glass sheet. 
     
     
         4 . The apparatus of  claim 1 , wherein each of the first grinding wheel and the second grinding wheel independently have an average particle size in the range of about 200 μm to about 3 μm. 
     
     
         5 . The apparatus of  claim 1 , wherein the first grinding wheel and the second grinding wheel are compliant urethane based wheels. 
     
     
         6 . The apparatus of  claim 1 , wherein the first spindle and the second spindle are spaced apart by greater than or equal to a radius of the first grinding wheel or second grinding wheel plus 10 mm. 
     
     
         7 . The apparatus of  claim 1 , wherein each of the first motor and the second motor are movable in the Z-axis a distance equal to or greater than 60 mm away from the worktable. 
     
     
         8 . The apparatus of  claim 1 , wherein the worktable is configured to move the glass sheet in a plane formed by the X-axis and Y-axis adjacent the first grinding wheel and the second grinding wheel. 
     
     
         9 . The apparatus of  claim 8 , wherein the worktable is configured to move the glass sheet at a rate in the range of about 5 m/min to about 30 m/min. 
     
     
         10 . The apparatus of  claim 1 , wherein each of the first grinding wheel and the second grinding wheel have a thickness sufficient to provide greater than or equal to about 25 mm of contact. 
     
     
         11 . The apparatus of  claim 1 , wherein the first motor and the second motor are pushed toward the worktable. 
     
     
         12 . The apparatus of  claim 11 , further comprising one or more of air bearings or force transducers coupled to the first motor and the second motor. 
     
     
         13 . The apparatus of  claim 1 , wherein the first motor and the second motor are configured to operate at a speed in the range of about 600 rpm to about 3000 rpm. 
     
     
         14 . The apparatus of  claim 1 , further comprising a plurality of first peripheral liquid cooling nozzles adjacent the first spindle and positioned to direct cooling liquid toward the peripheral edge of the first grinding wheel, and a plurality of second peripheral liquid cooling nozzles adjacent the second spindle and position to direct cooling liquid toward the peripheral edge of the second grinding wheel. 
     
     
         15 . The apparatus of  claim 1 , further comprising a plurality of remote liquid cooling nozzles positioned remotely from the first grinding wheel and the second grinding wheel and positioned to direct cooling liquid toward an edge of the glass sheet. 
     
     
         16 . A method of finishing an edge of a glass sheet, the method comprising:
 supporting a glass sheet on a worktable, a portion of the glass sheet extending a distance from the worktable, the glass sheet comprising a first surface, a second surface opposing the first surface and an end surface, the first surface and end surface intersect along a first edge and the second surface and the end surface intersect along a second edge, wherein an X-axis is a direction of lateral movement on a plane of a glass sheet on the surface, a Y-axis is a direction of longitudinal movement on the plane which is perpendicular to the X-axis, and a Z-axis is a direction of movement orthogonal to the plane;   contacting the first edge with a peripheral edge of at least one first grinding wheel positioned on a first spindle axis of a first motor, the first grinding wheel substantially disc-shaped;   contacting the second edge with a peripheral edge of at least one second grinding wheel positioned on a second spindle axis of a second motor, the second grinding wheel substantially disc-shaped; and   producing relative motion between the first and second grinding wheels and the glass sheet during contacting of the first and second grinding wheels with the first and second edges, respectively, to chamfer the first edge and second edge.   
     
     
         17 . The method of  claim 16 , wherein the chamfer is less than or equal to about 5% of a thickness of the glass sheet. 
     
     
         18 . The method of  claim 16 , wherein the worktable is configured to move the glass sheet at a rate in the range of about 5 m/min to about 30 m/min. 
     
     
         19 . The method of  claim 16 , wherein each of the first grinding wheel and the second grinding wheel have a thickness sufficient to provide greater than or equal to about 25 mm of contact. 
     
     
         20 . The method of  claim 16 , further comprising providing a force to push the first motor and the second motor toward the worktable.