Method For Manufacturing Ophthalmic Lenses Using Circular Blanks

Abstract

For manufacturing ophthalmic lenses and other optical form bodies made of plastic material, plastic form parts are used which are made by non-cutting shaping and are then further worked by mechanical production steps. Said plastic form parts are circular blanks ( 1 ) made of two different plastic materials which are firmly joined to each other. Thereby, an interior lens element ( 2 ) that consists of a high-quality material is concentrically surrounded by a ring fixture ( 3 ) which consists of a low priced material. Either surface of the lens element ( 2 ) may feature any given geometry. During mechanical working, the ring fixture ( 3 ) is used for mounting as well as for depositing and, in addition, for stabilizing the workpiece ( 9 ). For this reason it is partially maintained throughout the mechanical working and is cut off at the end only.

1 - 19 . (canceled) 
   
   
       20 . A circular blank for manufacturing ophthalmic lenses and other form bodies made of plastic material, comprising a lens element made of a high-quality optical material which is worked using mechanical production steps, wherein the lens element is surrounded by a ring fixture made of a low-cost material, wherein the lens element and the ring fixture made of two different plastic materials are firmly connected to each other, and wherein the ring fixture is mountable in a mounting tool of a working machine and is machinale together with the lens element. 
   
   
       21 . The circular blank according to  claim 20 , wherein the ring fixture has a recess for receiving the lens element. 
   
   
       22 . The circular blank according to  claim 21 , wherein the recess is provided with a flange to support the lens element. 
   
   
       23 . The circular blank according to  claim 20 , wherein the ring fixture has ribs, webs or the like with spaces ( 37 ) in-between. 
   
   
       24 . The circular blank according to  claim 23 , wherein the ribs are radially arranged. 
   
   
       25 . The circular blank according to  claim 20 , wherein the periphery of the ring fixture is provided with a collar. 
   
   
       26 . The circular blank according to  claim 20 , wherein the ring fixture is concentric to the lens element. 
   
   
       27 . The circular blank according to  claim 20 , wherein the ring fixture is an injection moulded part. 
   
   
       28 . The circular blank according to  claim 20 , wherein the ring fixture is bonded to the lens element, for example by an adhesive. 
   
   
       29 . The circular blank according to  claim 20 , wherein the ring fixture includes at least one member for mechanical registration. 
   
   
       30 . The circular blank according to  claim 20 , wherein the ring fixture is a handle. 
   
   
       31 . A circular blank according to  claim 20  for use in manufacturing ophthalmic lenses and other form bodies made of plastic material