An improved method of preparing a lens blank for an operation of surfacing thereof

Abstract

A method of preparing a lens blank for a further operation of surfacing to transform the lens blank into a surfaced lens for further transformation into a lens having a lens shape, the operation of surfacing including processing the lens blank so that the surfaced lens exhibits a crib diameter, the method being implemented using a processing module and comprising: based on input data (ID) which define the lens shape, defining a temporary crib diameter (Dtemp) so that said temporary crib diameter satisfies a set of constraints which includes at least: a first constraint whereby the temporary crib diameter (Dtemp) is large enough for the surfaced lens having said temporary crib diameter to be suitable to be processed into said lens, a second constraint whereby the temporary crib diameter is large enough for the surfaced lens having said temporary crib diameter to include a plurality of reference points defined on the lens blank and which together identify an optical center of the lens, choosing the crib diameter as a function of the temporary crib diameter (Dtemp), said choosing the crib diameter being configured so that, when a step cribbing configuration is destined to be applied to the operation of surfacing, said crib diameter is chosen among at least one predetermined discrete value (Vali).

1 - 14 . (canceled) 
     
     
         15 . A method of preparing a lens blank for a further operation of surfacing of said lens blank configured to transform the lens blank into a surfaced lens at the end thereof for further transformation into a lens having a lens shape and destined to be coupled to a frame, the operation of surfacing including processing the lens blank so that the surfaced lens exhibits a crib diameter, the method being implemented using a processing module and comprising:
 based on input data which define the lens shape, defining a temporary crib diameter so that said temporary crib diameter satisfies a set of constraints which includes at least:
 a first constraint whereby the temporary crib diameter is large enough for the surfaced lens having said temporary crib diameter to be suitable to be processed into said lens, and 
 a second constraint whereby the temporary crib diameter is large enough for the surfaced lens having said temporary crib diameter to include a plurality of reference points defined on the lens blank and which together identify an optical center of the lens; and 
   choosing the crib diameter as a function of the temporary crib diameter, said choosing the crib diameter being configured so that, when a step cribbing configuration is destined to be applied to the operation of surfacing, said crib diameter is chosen among at least one predetermined discrete value.   
     
     
         16 . The method according to  claim 15 , wherein the crib diameter is chosen as corresponding to the smallest discrete value which is superior to the temporary crib diameter. 
     
     
         17 . The method of  claim 15 , further comprising, when a surface extension configuration is destined to be applied to the operation of surfacing, generating a surface file to be used during the operation of surfacing for generating the lens shape so that the lens shape is circular with a diameter corresponding to the crib diameter. 
     
     
         18 . The method of  claim 17 , wherein the crib diameter is chosen as corresponding to the smallest discrete value which is superior to the temporary crib diameter, and
 wherein said one or more predetermined discrete value is formed by a single value.   
     
     
         19 . The method of  claim 15 , wherein the temporary crib diameter is chosen as the smallest value which satisfies said set of constraints. 
     
     
         20 . The method of  claim 15 , wherein the set of constraints includes a third constraint according to which the temporary crib diameter is superior or equal to a minimum crib diameter of an apparatus destined to be used to reduce the diameter of the lens blank during the operation of surfacing. 
     
     
         21 . The method of  claim 15 , wherein, for satisfying the first constraint, the temporary crib diameter is taken as superior or equal to a lens shape parameter defined based on twice a maximum radius of the lens shape. 
     
     
         22 . The method of  claim 15 , wherein the lens shape parameter is taken equal as twice the radius of the lens shape when the generated lens shape is circular. 
     
     
         23 . The method of  claim 15 , wherein the lens shape parameter is taken equal as twice the sum of the maximum radius and of a margin defined based on a shape of the frame the lens is destined to be coupled to. 
     
     
         24 . The method of  claim 15 , wherein for satisfying the second constraint, the temporary crib diameter is chosen superior or equal to a reference parameter defined based on twice a distance between a center of the lens shape in a blocking and turning referential of the lens blank during the operation of surfacing and the reference point of the lens blank which is the farthest away from said center. 
     
     
         25 . The method according to  claim 24 , wherein the reference parameter is taken equal to twice the sum of said distance and of a predetermined margin. 
     
     
         26 . A non-transitory computer-readable medium comprising a computer program stored thereon and including instructions for the implementation of the method according to  claim 15  when the instructions are executed by a processor. 
     
     
         27 . A method of surfacing a lens blank configured to transform the lens blank into a surfaced lens at the end thereof for further transformation into a lens having a lens shape and destined to be coupled to a frame, the method comprising:
 preparing the lens blank for surfacing using a method of preparing a lens blank  claim 15  to obtain a crib diameter; and   surfacing the lens blank, said surfacing the lens blank including processing the lens blank so that the surfaced lens exhibits the crib diameter.   
     
     
         28 . A device for preparing a lens blank for a further operation of surfacing of said lens blank configured to transform the lens blank into a surfaced lens having a lens shape at the end thereof for further transformation into a lens to be coupled to a frame, the operation of surfacing including processing the lens blank so that the surfaced lens exhibits a crib diameter, the device comprising:
 a processing module configured to:   based on input data which define the lens shape, define a temporary crib diameter so that said temporary crib diameter satisfies a set of constraints which includes at least:   a first constraint whereby the temporary crib diameter is large enough for the surfaced lens having said temporary crib diameter to be suitable to be processed into said lens,   a second constraint whereby the temporary crib diameter is large enough for the surfaced lens having said temporary crib diameter to include a plurality of reference points defined on the lens blank and which together identify an optical center of the lens, and   choose the crib diameter as a function of the temporary crib diameter, the processing module being configured to choose the crib diameter so that, in response to a step cribbing configuration being destined to be applied to the operation of surfacing, said crib diameter is chosen among at least one predetermined discrete value.