Mirror grinding method and glass lens

Abstract

A mirror surface grinding method processes an optical glass material into a lens shape using a cup-shaped grinding stone. The grinding stone is pupplied with a polishing solution which contains charged fine particles, thereby electrically attaching the charged fine particles to the grinding stone. The grinding stone is rotated and moved relative to the optical glass material along a final shape to be generated from the optical glass material, thereby grinding an unnecessary portion of the optical glass material to remove it, using a peripheral face portion of the grinding stone, and at the same time polishing the final shape surface of the optical glass material using charged fine particles attached to an annular face portion of the rotating and moving grinding stone.

1 . A mirror surface grinding method for processing an optical glass material into a desired shape using a grinding stone, comprising the steps of: 
 supplying the grinding stone with a polishing solution which contains charged fine particles, thereby electrically attaching the charged fine particles to the grinding stone; and    rotating and moving the grinding stone relative to the optical glass material along a final shape to be generated from the optical glass material, thereby grinding an unnecessary portion of the optical glass material to remove it, using a side face portion of the grinding stone, and at the same time polishing the final shape surface of the optical glass material using charged fine particles attached to a front face portion of the rotating and moving grinding stone.    
     
     
         2 . A method according to  claim 1 , wherein the grinding stone is cup-shaped such that the front face portion is an annular face portion.  
     
     
         3 . A method according to  claim 2 , wherein the front face portion of the grinding stone is tapered from a side-face-portion side toward an axis of the grinding stone.  
     
     
         4 . A method according to  claim 1 , wherein the front face portion of the grinding stone includes at least two concentric annular face portions of different levels.  
     
     
         5 . A method according to  claim 1 , further comprising, after the step of polishing the final shape surface of the optical glass material using the fine particles attached to the front face portion of the grinding stone, a step of defining a clearance between the polished final shape surface and the front face portion of the grinding stone by separating the grinding stone from the final shape surface, and further polishing the final shape surface using fine particles attached to the front face portion.  
     
     
         6 . A mirror surface grinding method for processing an optical glass material into a desired shape using a grinding stone, comprising the steps of: 
 supplying the grinding stone with a polishing solution which contains charged fine particles, thereby electrically attaching the charged fine particles to the grinding stone;    linearly cutting the optical glass material by a front face portion of the grinding stone until the front face portion reaches a portion of the optical glass material from which a final shape surface is to be generated, while rotating the grinding stone; and    rotating the optical glass material after finishing the linearly cutting, and rotating and moving the grinding stone relative to the optical glass material along a final shape to be generated from the optical glass material, thereby grinding an unnecessary portion of the optical glass material to remove it, using a side face portion of the grinding stone, and at the same time polishing the final shape surface of the optical glass material using charged fine particles attached to the front face portion of the rotating and moving grinding stone.    
     
     
         7 . A method according to  claim 6 , wherein the grinding stone is cup-shaped.  
     
     
         8 . A method according to  claim 6 , wherein the step of electrically attaching the fine particles to the grinding stone is performed when the front face portion of the grinding stone has reached at least a portion of the optical glass material from which the final shape surface is to be generated.  
     
     
         9 . A method according to  claim 6 , further comprising, after the step of polishing the final shape surface of the optical glass material using the fine particles attached to the front face portion of the grinding stone, a step of defining a clearance between the polished final shape surface and the front face portion of the grinding stone by separating the grinding stone from the final shape surface, and further polishing the final shape surface using fine particles attached to the front face portion.  
     
     
         10 . A mirror surface grinding method for processing an optical glass material into a desired shape using a grinding stone, comprising the steps of: 
 rotating at least one of the grinding stone and the optical glass material and at the same time linearly cutting the optical glass material by a front face portion of the grinding stone until the front face portion reaches a portion of the optical glass material from which a final shape surface is to be generated; and    supplying the grinding stone with a polishing solution which contains charged fine particles, when the front face portion of the grinding stone has reached at least the portion of the optical glass material from which the final shape surface is to be generated, and polishing the final shape surface using the fine particles attached to the front face portion of the grinding stone while rotating both the grinding stone and the optical glass material, after the step of electrically attaching the fine particles to the grinding stone and the step of the linear cutting.    
     
     
         11 . A method according to  claim 10 , wherein the grinding stone is cup-shaped.  
     
     
         12 . A method according to  claim 11 , further comprising a step of inclining an axis of rotation of the optical glass material and an axis of rotation of the grinding stone at angles determined from a swivel angle employed in the case of a curve generator.  
     
     
         13 . A method according to  claim 10 , wherein the step of polishing the final shape surface by the fine particles is performed with the positional relationship between the grinding stone and the optical glass material maintained, after the linear cutting is finished.  
     
     
         14 . A method according to  claim 10 , wherein the step of polishing the final shape surface by the fine particles is performed with a clearance defined between the grinding stone and the optical glass material, after the linear cutting is finished.  
     
     
         15 . A glass lens ground by the grinding method described in  claim 1 , which has a polishing trace formed on its surface by fine particles attached to the grinding stone as a result of the electrophoresis phenomenon, the polishing trace having a regular pattern and a depth of 10 nm or less.  
     
     
         16 . A glass lens ground by the grinding method described in  claim 6 , wherein the front face portion of the grinding stone includes at least two concentric annular face portions of different levels.  
     
     
         17 . A glass lens ground by the grinding method described in  claim 10 , wherein the front face portion of the grinding stone includes at least two concentric annular face portions of different levels.  
     
     
         18 . A mirror surface grinding method for processing an optical glass material into a desired shape using a grinding stone, comprising the steps of: 
 preparing a grinding stone which has a shape generating face for cutting the optical glass material to thereby grind the optical glass material, and a polishing face for polishing a surface generated by the shape generating face;    holding the optical glass material on holding means;    supplying a polishing solution which contains charged fine particles, between the grinding stone and the optical glass material; and    moving at least one of the grinding stone and the optical glass material relative to each other, cutting the optical glass material by the shape generating face of the grinding stone to thereby grind the optical glass material into a desired shape surface, and at the same time polishing the desired shape surface by the fine particles attached to the polishing face of the grinding stone, while electrically attaching fine particles to the grinding stone on a continuous basis.    
     
     
         19 . A method according to  claim 18 , wherein the grinding stone is cup-shaped.  
     
     
         20 . A method according to  claim 18 , further comprising, after the step of polishing the desired shape surface, a step of separating the grinding stone from the optical glass material, and continuing polishing using fine particles attached to the polishing face of the grinding stone.  
     
     
         21 . A mirror surface grinding method for processing an optical glass material into a desired shape using a grinding stone, comprising the steps of: 
 preparing a cup-shaped grinding stone which has a shape generating face for cutting the optical glass material to thereby grind the optical glass material, and a polishing face for polishing a surface generated by the shape generating face;    holding the optical glass material on holding means;    supplying a polishing solution which contains charged fine particles, between the grinding stone and the optical glass material; and    moving at least one of the grinding stone and the optical glass material relative to each other, and cutting, using a front face portion of the grinding stone, the optical glass material to a portion of the material from which a desired shape surface is generated; and    moving at least one of the grinding stone and the optical glass material relative to each other, and cutting, using a side face portion of the grinding stone, the optical glass material into the desired shape surface, and at the same time polishing the desired shape surface by the fine particles attached to the front face portion of the grinding stone, while electrically attaching fine particles to the grinding stone on a continuous basis.    
     
     
         22 . A method according to  claim 21 , further comprising, after the step of polishing the final shape surface of the optical glass material using the fine particles, the step of defining a clearance between the polished final shape surface and the grinding stone by separating the grinding stone from the optical glass material, and further polishing the final shape surface using fine particles attached to and grown on the front face portion of the grinding stone.  
     
     
         23 . A glass lens obtained by rotating a grinding stone and an optical glass material, moving them relative to each other, thereby grinding the optical glass material by the grinding stone, the glass lens having a trace of a regular pattern.  
     
     
         24 . A glass lens according to  claim 23 , wherein the regular pattern consists of a group of striped polishing traces.