Method for deciding a bevel curve, method for deciding a locus of a bevel, method for processing a lens and apparatus for processing a lens

摘要

Enabling the formation of a suitable bevel in special lenses such as an EX lens even by a person not skilled in the art. When a bevel is formed on an EX lens, the value of the bevel curve is decided based on the value of the curve of the concave face (S711), a reference axis of the bevel curve is decided in the same direction as the direction of the curvature of the concave face (S712), a reference position on the peripheral edge in the portion having the minimum thickness at the lower side in the vertical direction is decided based on the thickness of the portion having the minimum thickness (S713), a correction for the initial reference axis of the bevel curve is obtained based on the ratio of the thickness of the portion having the maximum thickness at the upper side in the vertical direction to the thickness of the portion having the minimum thickness (S714), an angle of inclination of the axis from the direction of the initial reference axis of the bevel curve is obtained based on the correction (S715) and the locus of the bevel is decided based on the value of the bevel curve, the reference position and the angle of inclination of the axis (S716).