Essilor International (Compagnie Generale D'optique)

Essilor International Cie Generale D'optique

Bernard Cousyn

Ahmed Haddadi

Pascal Daboudet

Jean-Claude Hennequin

In a method for bevelling an ophthalmic lens, the lens is rotated about its own axis and is also displaced parallel to its axis as a function of its angle of rotation. Simultaneously, the edge of the lens is kept in contact with a grinding wheel. Thus the point of contact of the lens with the grinding wheel is constrained to follow a specific path. The specific path to be followed by the point of contact is an intermediate path selected between two paths resulting from a comparison between a collection of predetermined paths and two reference paths. The reference paths are each obtained from a plotting operation carried out prior to the bevelling operation on the ophthalmic lens using feelers. This method is used in grinding machines such that trimming and bevelling of ophthalmic lenses can be automatically performed.

Grinding machine for forming the edge of an ophthalmic lens

A device (1) for measuring the ocular parameters of a subject is of conventional optical design, with a front panel (10), a convergent lens (11), an aiming hole (12) at the focus of the lens (11), and a light source (13) whose image in a semi-reflecting mirror (14) appears as a point at infinity. Liquid crystal matrixes are disposed in windows (15, 16, 17, 18) and controlled by a logic unit (20) connected to a control keyboard (21) and a display (22). Looking through the hole (12), the operator uses the keyboard (21) to send address signals from the logic unit (20) either to the columns of the top matrixes (15, 16) or to the lines of the top and bottom matrixes (15, 16, 17, 18). According to the operating modes selected, vertical lines appear in the top windows (15, 16) to measure the interpupillary distance or horizontal lines appear in all four windows for centering the lenses in the frame.

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Vincennes, France

Bernard Cousyn