Polishing film for plastic spectacle lenses

Abstract

A polishing film for a polishing head for plastic spectacle lenses, for polishing zones on a front side or rear side of the spectacle lens, having a polishing surface which can be positioned against the spectacle lens and is bounded by a peripheral surface, wherein an edge is provided between the polishing surface and the peripheral surface, wherein the edge either has a radius r of at least 0.5 mm to 10 mm or has a chamfer f with an extent f1×f2, where the extent f1 or f2 is at least 0.5 mm to 10 mm, or the polishing film, when not in use, has a basic curvature G with a radius RG≧75 mm and, in addition to this, a peripheral curvature G with a radius Rg≦0.5 G, wherein the peripheral curvature g is limited to the peripheral zone, or the polishing film is formed without any basic curvature G and has a peripheral curvature g with a radius Rg≦35 mm, wherein the peripheral curvature g is limited to the peripheral zone.

What is claimed is: 
     
         1 . A polishing film for a polishing head for plastic spectacle lenses for zone polishing of a front side or rear side of the spectacle lens, comprising: a polishing surface which can be positioned against the spectacle lens, being bounded by a peripheral surface, while an edge is formed between the polishing surface and the peripheral surface, wherein the edge has a radius r of at least 0.2 mm to 10 mm. 
     
     
         2 . A polishing film for a polishing head for plastic spectacle lenses for zone polishing of a front side or rear side of the spectacle lens, comprising: a polishing surface which can be positioned against the spectacle lens, being bounded by a peripheral surface, while an edge is formed between the polishing surface and the peripheral surface, wherein the edge has a chamfer f with a dimension of f1×f2, where the dimension f1 or f2 is at least 0.2 mm to 10 mm. 
     
     
         3 . The polishing film according to  claim 1 , wherein the radius r is worked into the polishing film by a cutting process or a grinding process. 
     
     
         4 . A polishing film for a polishing head for plastic spectacle lenses for zone polishing of a front side or rear side of the spectacle lens, comprising: a polishing surface which can be positioned against the spectacle lens, having a basic diameter D, wherein the polishing film is secured to an elastic carrier layer with a diameter D1 and the polishing surface has a peripheral zone with a width b of at most 0.1 D to 0.3 D, 
       wherein the diameter D1 is: D1=D−2b or D1<D−2b and
 the polishing film in the unused state prior to being placed against a spectacle lens 
 a1) has a basic curvature G with a radius RG>=70 mm and in addition to this it has a peripheral curvature g with a radius Rg<=0.5 G, the peripheral curvature g being confined to the peripheral zone, or 
 a2) the polishing film is formed with no basic curvature G and it has a peripheral curvature g with a radius Rg<=35 mm, the peripheral curvature g being confined to the peripheral zone. 
 
     
     
         5 . The polishing film according to  claim 4 , wherein the peripheral curvature g is limited to a maximum of 10% of the peripheral zone. 
     
     
         6 . A polishing head with a polishing film according to  claim 1  for zone polishing of a spectacle lens. 
     
     
         7 . A method for producing a polishing film for a polishing head for plastic spectacle lenses for zone polishing of a front side or rear side of the spectacle lens, with a polishing surface which can be positioned against the spectacle lens, being bounded by a peripheral surface, while an edge is formed between the polishing surface and the peripheral surface, comprising the steps of:
 a) carving the polishing film out from a web of material,   b) bringing the polishing film up to a cutting tool and the edge is broken off by the cutting tool.   
     
     
         8 . A method for producing a polishing film for a polishing head for plastic spectacle lenses for zone polishing of a front side or rear side of the spectacle lens, with a polishing surface which can be positioned against the spectacle lens, having a basic diameter D, comprising the steps of:
 a) carving the polishing film out from a web of material, wherein the polishing surface has a peripheral zone with a width of at most 0.3 D,   b1) providing the polishing film with a basic curvature G, with G>=70 mm, and in addition to this it is provided with an extra peripheral curvature g in a shaping process in the peripheral zone, prior to the use for a spectacle lens being manufactured, with a radius Rg<=0.5 G, or   b2) configuring the polishing film without a basic curvature G, and it is provided with a peripheral curvature g located exclusively in the peripheral zone in a shaping process prior to the use for a spectacle lens being manufactured.   
     
     
         9 . The method for producing a polishing head with a polishing film according to  claim 7 , wherein the polishing film is secured to an elastic carrier layer of a polishing head, wherein the breaking of the edge occurs after the fastening on the carrier layer, wherein the polishing film is guided or supported indirectly by the carrier layer when machining the edge. 
     
     
         10 . A method for producing a polishing film for a polishing head for plastic spectacle lenses for zone polishing of a front side or rear side of the spectacle lens, with a polishing surface which can be positioned against the spectacle lens, having a basic diameter D, wherein the polishing surface has a peripheral zone with a width of at most 0.3 D, comprising the steps of:
 a) carving several polishing films out from a material web,   producing a structurized material web before step a), which has several formations whose shape corresponds to a polishing film with a peripheral curvature g arranged in the peripheral zone, and wherein the carving out of the polishing film from the structurized material web at the periphery of the respective formation produces a polishing film with a peripheral curvature g situated in the peripheral zone.   
     
     
         11 . The polishing film according to  claim 2 , wherein the chamfer f is worked into the polishing film by a cutting process or a grinding process. 
     
     
         12 . A polishing head with a polishing film according to  claim 2  for zone polishing of a spectacle lens. 
     
     
         13 . A polishing head with a polishing film according to  claim 4  for zone polishing of a spectacle lens. 
     
     
         14 . The method for producing a polishing head with a polishing film according to  claim 8 , wherein the polishing film is secured to an elastic carrier layer of a polishing head, wherein the molding of the peripheral curvature g occurs after the fastening on the carrier layer, wherein the polishing film is guided or supported indirectly by the carrier layer when machining the edge.