| 摘要 |
In an injection compression molding method of a lens, in which a mold is closed to preserve a predetermined compressing margin in a cavity (3) for a lens, molten resin is injected and fed into the cavity (3) for the lens, and compressed for the aforementioned predetermined compressing margin before or after the injection and the feed of the molten resin is completed, the predetermined compressing margin (the degree of slightly opening S (-)) for producing a minus lens is molded is defined to be larger than the predetermined compressing margin (the degree of slightly opening S (+)) for producing a plus lens is molded. As a result, even when the minus lens is molded, the larger area of the cavity can be ensured and a flow property of the molten resin in the cavity is improved, so that the molten resin reaching the inside of the cavity (3) flows through the central portion of the cavity (3) into the peripheral portion, with the result that the appearance of a weld mark in the central portion is avoided. <IMAGE> |
