METHOD OF CALCULATING A SETPOINT FOR BEVELING OR GROOVING AN OPHTHALMIC LENS
First Claim
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1. A method of calculating the shape of a longitudinal profile of an engagement ridge or groove (28) for machining on the edge face (23) of an ophthalmic lens (20), the method comprising:
- an operation of acquiring the shape of an initial longitudinal profile (29);
an operation of prepositioning said initial longitudinal profile (29) in a coordinate system tied to the ophthalmic lens (20);
an operation of searching for two remarkable points (Pr1, Pr2) of said initial longitudinal profile (29), which points are distinct from each other, said operation comprising;
a) acquiring a plurality of characteristics (Ep, Dav, Dar) relating to the ophthalmic lens (20) or to the initial longitudinal profile (29);
b) determining whether any of said acquired characteristics satisfies a decision criterion, by comparing the value of said acquired characteristic with a predetermined threshold value;
c) selecting the first remarkable point (Pr1) from a first list of points of said initial longitudinal profile (29) as being the point at which one of said acquired characteristics satisfies a first positioning criterion, said first positioning criterion being selected as a function of the result of step b); and
d) selecting the second remarkable point (Pr2) from a second list of points of said initial longitudinal profile (29), as being the point at which one of said acquired characteristics satisfies a second positioning criterion, said second list being deduced from the result of step c);
an operation of correcting the position of each remarkable point (Pr1, Pr2) along an axial direction (Z1) substantially perpendicular to a mean plane of the ophthalmic lens (20); and
an operation of calculating the three-dimensional shape of a final longitudinal profile (29′
) in the coordinate system of the ophthalmic lens (20), resulting from a geometrical transformation of the initial longitudinal profile (29) that is such as to cause the final longitudinal profile (29′
) to pass via the first and second remarkable points (Pr1, Pr2) as modified during the preceding operation.
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Abstract
A method of calculating a shaping setpoint for an ophthalmic lens along a longitudinal profile includes:
- an operation of acquiring an initial longitudinal profile;
- an operation of centering the initial longitudinal profile on the lens;
- an operation of searching for two remarkable points of the initial longitudinal profile as a function of determined criteria;
- an operation of calculating a modified axial coordinate for each remarkable point in order to ensure proper mounting and esthetic appearance of the lens in its eyeglass frame; and
- an operation of calculating a final longitudinal profile resulting from a transformation of the initial longitudinal profile that is such that the final longitudinal profile passes through the two remarkable points.
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Citations
15 Claims
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1. A method of calculating the shape of a longitudinal profile of an engagement ridge or groove (28) for machining on the edge face (23) of an ophthalmic lens (20), the method comprising:
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an operation of acquiring the shape of an initial longitudinal profile (29); an operation of prepositioning said initial longitudinal profile (29) in a coordinate system tied to the ophthalmic lens (20); an operation of searching for two remarkable points (Pr1, Pr2) of said initial longitudinal profile (29), which points are distinct from each other, said operation comprising; a) acquiring a plurality of characteristics (Ep, Dav, Dar) relating to the ophthalmic lens (20) or to the initial longitudinal profile (29); b) determining whether any of said acquired characteristics satisfies a decision criterion, by comparing the value of said acquired characteristic with a predetermined threshold value; c) selecting the first remarkable point (Pr1) from a first list of points of said initial longitudinal profile (29) as being the point at which one of said acquired characteristics satisfies a first positioning criterion, said first positioning criterion being selected as a function of the result of step b); and d) selecting the second remarkable point (Pr2) from a second list of points of said initial longitudinal profile (29), as being the point at which one of said acquired characteristics satisfies a second positioning criterion, said second list being deduced from the result of step c); an operation of correcting the position of each remarkable point (Pr1, Pr2) along an axial direction (Z1) substantially perpendicular to a mean plane of the ophthalmic lens (20); and an operation of calculating the three-dimensional shape of a final longitudinal profile (29′
) in the coordinate system of the ophthalmic lens (20), resulting from a geometrical transformation of the initial longitudinal profile (29) that is such as to cause the final longitudinal profile (29′
) to pass via the first and second remarkable points (Pr1, Pr2) as modified during the preceding operation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification