Grindstone and method for producing optical element

Abstract

A grindstone 1 has a pedestal 2 and an abrasive-grain layer 9 provided on the pedestal 2 . The abrasive-grain layer 9 is a plating film which contains abrasive grains. An intermediate layer 7 which has physical properties different from those of the abrasive-grain layer 9 is provided between the abrasive-grain layer and the pedestal. The intermediate layer 7 is a plating film which contains abrasive grains, and the plating film of this intermediate layer 7 has a color tone different from the color tone of the plating film of the abrasive-grain layer 9 . As being so made up, in the grindstone having an abrasive-grain layer formed of a plating film as a binder, the grindstone lifetime can be judged with ease.

1 . A grindstone comprising a pedestal and an abrasive-grain layer provided on the pedestal; wherein, 
 said abrasive-grain layer is a plating film which contains abrasive grains; and    an intermediate layer which has physical properties different from those of said abrasive-grain layer being provided between said abrasive-grain layer and said pedestal.    
     
     
         2 . A grindstone comprising a pedestal and an abrasive-grain layer provided on the pedestal; wherein, 
 said abrasive-grain layer is a plating film which contains abrasive grains; and    an intermediate layer which has optical characteristics different from those of said abrasive-grain layer is provided between said abrasive-grain layer and said pedestal.    
     
     
         3 . A grindstone comprising a pedestal and an abrasive-grain layer provided on the pedestal; wherein, 
 said abrasive-grain layer is a plating film which contains abrasive grains; and    an intermediate layer which has a coefficient of dynamic friction to a workpiece, different from that of said abrasive-grain layer is provided between said abrasive-grain layer and said pedestal.    
     
     
         4 . The grindstone according to  claim 2 , wherein; 
 said intermediate layer is a plating film which contains abrasive grains, and the plating film has a color tone different from the color tone of said plating film of said abrasive-grain.    
     
     
         5 . The grindstone according to  claim 4 , wherein; 
 said plating film of said intermediate layer is a black nickel plating film, and said plating film of said abrasive-grain is a silver white plating film.    
     
     
         6 . The grindstone according to  claim 4 , wherein; 
 of said plating film of said intermediate layer and said plating film of said abrasive-grain, one is a nickel plating film and the other is a copper plating film.    
     
     
         7 . The grindstone according to  claim 3 , wherein; 
 said intermediate layer is a plating film which contains abrasive grains, and the plating film has a hardness different from the hardness of said plating film of said abrasive-grain.    
     
     
         8 . The grindstone according to  claim 3 , wherein; 
 said intermediate layer is a plating film which contains abrasive grains, and the plating film is different from said abrasive-grain layer in at least one of a particle diameter and a density of said abrasive grains contained.    
     
     
         9 . The grindstone according to  claim 8 , wherein; 
 said density of said abrasive grains contained said intermediate layer is higher than the density of said abrasive grains of said abrasive-grain layer.    
     
     
         10 . The grindstone according to  claim 3 , wherein; 
 said intermediate layer is a plating film which contains abrasive grains, and the plating film is so formed that at least one of the particle diameter and the density of the abrasive grains contained provides clogging conditions under which said intermediate layer causes clogging when a workpiece is worked with said intermediate layer.    
     
     
         11 . The grindstone according to  claim 1 , wherein; 
 said physical properties of said intermediate layer comprise a working rate which is very smaller than the rate of working of a workpiece by said abrasive-grain layer.    
     
     
         12 . The grindstone according to  claim 1 , wherein; 
 said plating film of said abrasive-grain is an electroless plating film.    
     
     
         13 . A working tool comprising a plurality of the grindstones according to any one of  claims 1  to  12 ; wherein, 
 said plurality of the grindstones is attached to a base plate.  
 
     
     
         14 . A method for producing an optical element by working a workpiece, wherein; 
 when the workpiece is worked by means of a grindstone, said grindstone has a pedestal, an abrasive-grain layer provided on the pedestal and formed of a plating film containing abrasive grains, and an intermediate layer provided between the pedestal and the abrasive-grain layer and having physical properties different from those of the abrasive-grain layer; wherein    the physical properties being inclusive of coefficient of dynamic friction to the workpiece and optical characteristics.    
     
     
         15 . The method for producing an optical element according to  claim 14 , wherein; 
 said plating film of said abrasive-grain is formed of an electroless plating film.    
     
     
         16 . The method for producing an optical element according to any one of claims  14  and  15 , wherein; 
 said workpiece comprises fluorite or quartz.  
 
     
     
         17 . A method for producing a projection exposure device having an optical system comprising a lens, wherein; 
 a grindstone is prepared which has a pedestal, an abrasive-grain layer provided on the pedestal and formed of a plating film containing abrasive grains, and an intermediate layer provided between the pedestal and the abrasive-grain layer and having physical properties different from those of the abrasive-grain layer; the physical properties being inclusive of coefficient of dynamic friction to a lens material, and optical characteristics; and    the lens material is worked by means of the grindstone, and the lens obtained by the working of the lens material is set in said optical system.    
     
     
         18 . The method for producing a projection exposure device according to  claim 17 , wherein; 
 said plating film of said abrasive-grain is formed of an electroless plating film.    
     
     
         19 . The method for producing a projection exposure device according to any one of claims  17  and  18 , wherein; 
 said lens material is fluorite or quartz.