COMPOSITE CONTACT LENS AND PRODUCTION METHOD FOR SUCH A LENS

• Main Author: SHOJI, NORIYUKI
• Format: Patent
• Language: English; French; German
• Published: 23.11.2011
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; CONTACT LENSES; OPTICS; PERFORMING OPERATIONS; PHYSICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURESAS SPECTACLES; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

An object of the present invention is to increase a strength against tension or tear in a shear direction from a convex surface of a lens to a concave surface or the concave surface to the convex surface, occurring during the ordinary handling, and to improve wearing feel. A composite contact lens has a central part consisting of a hard material and a peripheral part consisting of a hydrous soft material. The joint surface 3A between the central hard part 1 and the peripheral soft part 2 is formed of a single conical surface inclined so that a diameter D1 of the hard part 1 in the lens convex surface FC is larger than a diameter D2 of the hard part 1 in the lens concave surface BC, and an inclination angle a of the conical surface is set so that an angle ¸ formed by the joint surface 3A and the lens concave surface BC is approximately at 90°. An annular convex part 7 projecting forward with respect to a curve of the convex surface of an optical part and forming a concentric circle with respect to an optical axis L of the lens is formed on the joint part 3 between the central hard part 1 and the peripheral soft part 2 at the side of the lens convex surface FC.