Patent ID: 9481137
Filing Date: 2016-11-01
CPC Classification: B29C,B29D,B29L

Claim Text:
1. A method for producing a plastic lens wherein, when a plurality of plastic lenses having different optical surface shapes is molded simultaneously in a single molding die, cavities are designed such that each of the plastic lenses to be molded has a same volume, and a raw material resin is filled in the cavities by injection and is molded into a predetermined lens shape, the method comprising: setting temporal lens shapes of the plastic lenses such that the temporal lens shapes have a same diameter and a same central thickness, obtaining a virtual average thickness of the temporal lens shapes, taking a plastic lens having a largest virtual average thickness as a standard lens, and correcting a thickness of one or more of the other plastic lenses by taking into consideration a difference between a virtual average thickness of the one or more of the other plastic lenses and a virtual average thickness of the standard lens such that a central thickness of the one or more of the other plastic lenses becomes larger than a central thickness of the standard lens by an amount corresponding to the difference, whereby cavities for the plastic lenses to be molded have the same volume.