Multimaterial Block Piece

Abstract

The invention provides for a blocking piece comprised of at least two materials having different rigidity/stiffness/hardness, wherein at least one among the two materials is translucent and defines an annular junction surface with respect to the other material. The invention also provides for a process using such a block piece.

What is claimed is: 
     
         1 . A blocking piece having a workpiece mounting face portion for blocking a spectacle lens blank, the blocking piece comprising at least two materials having different rigidity/stiffness/hardness, characterized in that both materials are translucent and define an annular junction surface for one material with respect to the other material, wherein a first one of the at least two materials is formed to have an annular shape at least in part surrounding the second one of the at least two materials, so that the workpiece mounting face portion comprises a first surface having the first one of the at least two materials and a second surface having the second one of the at least two materials and defines a preconfigured un-deformable shape for receiving said spectacle lens blank thereon. 
     
     
         2 . The blocking piece according to  claim 1 , wherein both materials have different optical properties. 
     
     
         3 . The blocking piece according to  claim 1  wherein at least one, in particular both materials are transparent. 
     
     
         4 . The blocking piece according to  claim 1 , wherein one or both materials have similar optical properties compared to the lens to be blocked. 
     
     
         5 . The blocking piece according to  claim 1 , wherein one material is fixedly attached, in particular embedded into the other material. 
     
     
         6 . The blocking piece according to  claim 1 , wherein the perimeter of the blocking piece is made to conform in rigidity/stiffness/hardness the lens to be blocked. 
     
     
         7 . The blocking piece according to  claim 1 , comprising at least one of an annular glass insert over moulded in the second material and radial extending ribs extending in the first material. 
     
     
         8 . A method for manufacturing spectacle lenses using a blocking piece according to any one of the preceding claims, comprising the steps of
 (i) blocking a spectacle lens blank with its blocking face on the workpiece mounting face portion of the blocking piece with the aid of a blocking material,   (ii) processing the blocked spectacle lens blank on the second face and optionally the edge to obtain a processed spectacle lens, and   (iii) deblocking the processed spectacle lens from the block piece, with the characterizing feature that the spectacle lens blank remains on and lies against the workpiece mounting face portion throughout the whole processing stage or step (ii).   
     
     
         9 . The method according to  claim 8 , wherein the blocking material used to block the spectacle lens blank is already present in the blocking piece.