Essilor International Cie Generale D'optique

Essilor International (compagnie Generale D'optique)

William Lenne

Georges H Wajs

Christian Harsigny

Claude Bourset

Guy Rolland

Bruno Bettiol

Jean F Bourdot

An ophthalmic lens is described having a front face which is a surface of revolution and is located entirely in front of the transverse plane tangential to its center. The curve representing the half-meridian of this front face corresponds to the following general formula:

Ophthalmic lens having an aspheric surface

A molding assembly for casting soft contact lenses especially such lenses formed of hydrophobic material. Such a molding assembly comprises a molding cavity defined by the dies of the assembly and an annular gasket or sealing member joining the peripheries thereof. The perimeter of largest diameter of the molding cavity is defined by contact between a sealing ridge which is part of the concave die or the gasket or sealing member and a bearing surface which is part of the other of the concave die or the gasket or sealing member. The annular gasket or sealing member may have an annular skirt adapted to embrace the concave die in the closed position of the assembly. The gasket or sealing member is carried by the convex die and may be integrally formed in one piece with the convex mold.

Molding assembly for casting soft contact lenses

Two metallic half-moulds are produced from a prototype. The half-moulds have complementary mould faces which abut when the mould is closed, and moulding surfaces formed with annular rim depressions joined by a bridge cavity, each rim depression bordering a support surface for a false lens. A webbed frame front is moulded, false lenses are cut from that moulded front, and the mould faces which abut are set-back by a total amount corresponding to the shrinkage of the false lenses, so that the false lenses are gripped between the support surfaces and shape lens bezels in the rims when a frame front is moulded.

Process for the production of a mould for moulding a spectacle frame

An improved flexible contact lens is provided having hydrophilic and lipophobic properties which allow extended duration of wear by eliminating or greatly reducing the risk of rupture of the natural tear film produced by the cornea. These properties are achieved by crosslinking a selected water soluble polymer which has been grafted onto a pre-formed substrate, for example crosslinking polyvinyl pyrrolidone which has been previously grafted onto a silicone substrate. The grafting and the crosslinking are accomplished in separate stages.

Flexible contact lens

A copying machine which can reproduce convex or concave surfaces having smaller radii of curvature at the edge than at the center, for example the surfaces of moulds for making contact lenses, has a cam assembly including a cam with a part-cylindrical cam surface mounted on a base. The cam has a part-circular section in the plane perpendicular to the cam surface generatrices and a straight section tangential to and continuous with one end of the part-circular section. The latter is slidably mounted on a concentric part-circular guide on the base, allowing rotary movement about its geometric center. The guide and at least the part-circular section of the cam have complementary square profiles. The part-circular cam section may be locked in position on the guide by screws threaded into the guide and passing through a concentric part-circular slot in the cam. The machine has a feeler held against the cam surface, a work block movable perpendicularly to the cam surface generatrices, and a transmission for moving the work block in dependence on the movement of the feeler. The transmission is so arranged that when the feeler moves away from an axis parallel to the cam surface generatrices passing through the geometric center of the part-circular cam section the work block moves towards that axis. The transmission includes a pivoted lever. The work block and feeler may be pivoted to this on the same or opposite sides of its pivot. In the first case a tool carried by the work block is located on the opposite side of the axis to the lever, while in the second case it is located between the axis and the lever.

Growing community of inventors

Gagny, France

William Lenne