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AssigneeEssilor International (Compagnie Generale d'Optique)
InventorsLaurent Guillermin, Sylvaine Millet
Estimating the term…
Process for grinding the rim of an ophthalmic lens that has two opposite faces, following a predetermined contour corresponding to that of a ring of a spectacle frame in which the lens is intended to be mounted, the contour being delimited on each of the faces by an edge, and the process includes a plotting stage in which the three-dimensional shape of at least one of the edges is plotted. In the plotting stage, the edge is scanned on the illuminated face of lens using a light beam forming a light spot on the face, the successive positions of an image of the light spot are plotted simultaneously on optical reception elements pointing towards the light spot, and the three-dimensional shape of the edge is deduced from the plots made, machining of the lens being carried out according to the plot or plots.
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.
Machine for grinding the rim (4) of an ophthalmic lens (1) having a so-called front face (2) and a so-called 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, this contour to be formed being delimited on the front face (2) by a front edge (5) and on the rear face (3) by a rear edge (6), the machine (9) comprising a rotating support (10) for mounting the lens (1), a rotary grinding tool (12), means (M1) for moving the support (10) and the tool (12) with respect to each other in a direction parallel to the rotational axis (A1) of support (10), means for moving support (10) and the tool (12) with respect to each other in a direction perpendicular to the axis (A1) of support (10), a control unit (18) suitable for controlling said means of displacement (M1, M2), characterized in that it includes at least one optical measurement device (19, 20) containing a light source (21) producing a light beam (22, 22′) directed towards one of the faces (2, 3) of the lens (1) in order to form there a light spot (23, 23′), optical reception means (24) pointed towards said light spot (23, 23′) and connected to said control unit (18), the latter including means of calculation suitable for calculating the three-dimensional shape of at least one of the edges (5, 6) according to the plots produced on the optical reception means (24).
Dependencies are inferred from the claim text.