LOW DISTORTION MOLDING METHOD OF PLASTIC LENS AND MOLD

PROBLEM TO BE SOLVED: To provide a molding method for reducing the occurrence of distortion, capable of solving a problem wherein, since a standby time is required until a side gate part is cooled and sealed in order to compress a lens shape part in a plastic lens molding method due to a injection/compression molding method, the effect of a surface solidified layer is large in a relatively small-sized/thin-walled lens and it is necessary to increase compression pressure and, since a gate seal part is throttled, it is necessary to increase dwelling force until filling pressure is increased and/or sealed to cause molding distortion and it is difficult to obtain a highly precise lens. SOLUTION: In this low distortion molding method of the plastic lens, the cross-sectional area of the side gate part is maximized to enable the inflow of a resin at a relatively high speed while the vicinity of a gate is mechanically sealed immediately after the filling with the resin to reduce filling pressure and the pressure strain in a dwelling process and shape precision is ensured in a compression process relatively low in force. COPYRIGHT: (C)2005,JPO&NCIPI