Method of making polarizing glasses

Abstract

Polarizing glass articles and methods of manufacturing polarizing glass articles are disclosed. The method involves forming a polarizing layer on the surface of the glass article by ion-exchanging silver or copper into the surface.

1 - 6 . (canceled)  
   
   
       7 . A polarizing glass article made by a method comprising the steps of 
 melting a glass batch containing a halide capable of precipitating silver or copper halide;    cooling and shaping the melt into a glass article;    ion-exchanging silver or copper ions into the surface of the glass article;    subjecting the glass article to an elevated temperature for a period of time sufficient to generate and precipitate silver or copper halide crystals in a surface layer of the glass;    elongating the glass article under stress at a temperature above the annealing point of the glass to elongate the crystals in the direction of the stress; and    exposing the elongated glass article to a reducing atmosphere at an elevated temperature to initiate reduction of at least a portion of the silver or copper halide crystals to silver metal.    
   
   
       8 . A polarizing glass article comprising a glass having two outer layers containing elongated copper or silver metal particles and a central layer containing essentially no copper or silver halide crystals.  
   
   
       9 . The article of  claim 8 , wherein the concentration of silver or copper metal is greater than 0.5% by weight.  
   
   
       10 . The article of  claim 9 , wherein the outer layer is less than 10 microns thick.  
   
   
       11 . The article according to  claim 9 , wherein the outer layer is less than 50 microns thick.  
   
   
       12 . The article according to  claim 8 , wherein the concentration of silver or copper metal is greater than 0.1% by weight.  
   
   
       13 . The article of  claim 11 , wherein the outer layer is less than 10 microns thick.  
   
   
       14 . The article according to  claim 11 , wherein the outer layer is less than 50 microns thick.  
   
   
       15 . A polarizing glass article comprising a glass having two outer layers containing elongated copper or silver metal particles and a central layer containing essentially no copper or silver halide crystals, wherein the concentration of silver or copper metal in the outer layers is greater than 0.5% by weight and the outer layers are less than 50 microns thick.  
   
   
       16 . The polarizing glass article made according to the method of  claim 7 , wherein ion-exchanging silver or copper ions into the surface of the glass article means ion-exchanging to produce a silver or copper concentration greater than 0.1% by weight.  
   
   
       17 . The polarizing glass article made according to the method of  claim 7 , wherein ion-exchanging silver or copper ions into the surface of the glass article means ion-exchanging to produce a silver or copper concentration greater than 0.5% by weight.