Process for holding an optical lens on a holder of a lens machining equipment

Abstract

A process is provided for rapidly holding an optical article having a convex surface on a holder of a lens machining equipment, the holder being equipped with a suction chuck comprising a cavity with a side wall and sealing means on a front end of the side wall, comprising the following steps: /a/ providing a flexible curved wafer with a concave surface arranged to close the cavity at the front end of the side wall; /b/ a fixing step in which the wafer is fixed onto the holder by providing vacuum between the concave surface of the wafer and the suction chuck; and /c/ a pressing step in which the concave surface of the optical article is pressed onto the concave surface of the wafer, an adhesive material being arranged between the wafer and the optical article The assembly is tight enough for sustaining machining forces, and the lens can be released rapidly.

1 . A process for holding an optical article having a convex surface on a holder of a lens machining equipment, the holder being equipped with a suction chuck, the chuck comprising a cavity with a side wall and sealing means on a front end of the side wall, comprising the following steps:
 /a/ providing a flexible curved wafer with a concave surface arranged to close the cavity at the front end of the side wall;   /b/ a fixing step in which the wafer is fixed onto the holder by providing vacuum between the concave surface of the wafer and the suction chuck; and   /c/ a pressing step in which the concave surface of the optical article is pressed onto the concave surface of the wafer, an adhesive material being arranged between the wafer and the optical article.   
   
   
       2 . The process according to  claim 1 , wherein the flexible curved wafer is made of a thermoplastic material. 
   
   
       3 . The process according to  claim 1 , wherein the flexible curved wafer has a thickness comprised between 0.3 and 3 mm. 
   
   
       4 . The process according to  claim 1 , wherein the concave surface of the flexible curved wafer is spherical. 
   
   
       5 . The process according to  claim 1 , wherein the sealing means is selected in the list consisting of: a O-ring seal, a V-ring seal, a silicone ring. 
   
   
       6 . The process according to  claim 1 , wherein the adhesive material is selected in the list consisting of: a pressure sensitive adhesive, a hot melt adhesive, an instant curable adhesive, a UV curable adhesive, a thermal curable adhesive. 
   
   
       7 . The process according to  claim 1 , wherein the lens machining equipment is selected from a list comprising a lens surface generating machine, a lens polishing or fining machine, and an edging machine. 
   
   
       8 . The process according to  claim 1 , wherein the optical article is a semi-finished optical lens. 
   
   
       9 . The process according to  claim 1 , wherein the convex surface of the optical article is initially covered with a surface protective tape, and wherein the adhesive means adhere to the surface protective tape in step /c/. 
   
   
       10 . The process according to  claim 1 , wherein the suction chuck further comprises a rigid support arranged within the cavity, so that a rear surface of the flexible curved wafer is in contact with said rigid support on a side opposite to the wafer concave surface, once the wafer has been fixed to the holder in step /b/. 
   
   
       11 . A process for machining an optical article having a convex surface, comprising the following steps:
 /1/ holding the optical article on a holder of a lens machining equipment, using a holding process according to  claim 1 ;   /2/ machining the optical article;   /3/ removing the optical article together with the flexible curved wafer from the holder by removing the vacuum in the cavity of the suction chuck; and   /4/ removing the flexible curved wafer from the optical article.   
   
   
       12 . The process according to  claim 11 , wherein the flexible curved wafer is removed from the optical article in step /4/ by peeling said wafer off. 
   
   
       13 . The process according to  claim 11 , wherein the flexible curved wafer is removed from the optical article in step /4/ by irradiating or heating the film of pressure sensitive adhesive so that adhesion to the optical article is suppressed. 
   
   
       14 . A lens machining equipment comprising a holder being equipped with a suction chuck, the chuck comprising a cavity with a side wall and sealing means on a front end of the side wall. 
   
   
       15 . The lens machining equipment according to  claim 14 , wherein the suction chuck further comprises a rigid support arranged within the cavity, so that a rear surface of a flexible curved wafer with a concave surface is in contact with the rigid support on a side opposite to concave surface of the wafer, once the wafer has been fixed to the holder.