MOLD FOR PLASTIC MULTI-FOCUS SPECTACLE LENS AND SEMI-FINISH LENS

摘要

PROBLEM TO BE SOLVED: To accurately determine a horizontal reference line when a semi-finish lens is attached to a processing jig to prevent that an unnecessary mark remains in a spectacle frame when a semifinish lens is attached to a processing jig by carving a horizontal reference mark to the outside of a complete lens diameter. ;SOLUTION: Two horizontal reference marks 5 are carved in the outside of a lense diameter 2 after the completion of a lens on the horizontal reference line passing the geometrical center 6. One vertical reference mark 4 is carved from the inside of the lens diameter 2 after completion to the outside of the lens diameter 2. In consideration of the polymerization contraction of the plastic lens or the notch of the lens by the leak of the plastic raw material, the outer diameter 1 of a mold is formed so as to become larger than the outer diameter 2 of a completed lens. The lens processed into a concave surface under the processing conditions corresponding to a recipe is shaped in its outer periphery to be cut up to a predetermined lens diameter 2 and by this work, the horizontal reference mark 5 transferred so as to become a protruding surface is cut off and not present at a time of lense delivery.;COPYRIGHT: (C)1997,JPO