Patent ID: 6896587

Claim:
Process for grinding the rim ( 4 ) of an ophthalmic lens ( 1 ) having a front face ( 2 ) and a rear face ( 3 ) opposite one another, following a predetermined contour corresponding to that of the ring of a spectacle frame in which the lens ( 1 ) is intended to be mounted, said contour being delimited on the front face ( 2 ) by a front edge ( 5 ) and on the rear face ( 3 ) by a rear edge ( 6 ), with the process comprising a plotting stage in which the three-dimensional shape of at least one of the front ( 5 ) or rear ( 6 ) edges is plotted, characterized in that, in the plotting stage, said edge ( 5 , 6 ) is scanned on the illuminated face ( 2 , 3 ) of the lens ( 1 ) using a light beam ( 22 , 22 ′) forming a light spot ( 23 , 23 ′) on said face ( 2 , 3 ), the successive positions of an image ( 27 , 27 ′) of said light spot ( 23 , 23 ′) are plotted simultaneously, on optical reception means ( 24 ) pointing towards said light spot ( 23 , 23 ′), and the three-dimensional shape of said edge ( 5 , 6 ) is deduced from the plots carried out, and in that it comprises in addition a machining stage according to which the lens ( 1 ), while it is rotated, is brought into contact by its rim ( 4 ) with a grinding tool ( 12 ), and the relative positions of the lens ( 1 ) and the tool ( 12 ) are controlled according to the plot or plots.