| 摘要 |
PURPOSE:To form plastic lens with a high degree of accuracy by a method wherein a depressed part is formed in either if the matching faces of the inserts provided in a fixed side molding plate and a movable side molding plate of a die and a raised part slidably engageable with the depressed part is formed in the matching face of the other insert. CONSTITUTION:A die is provided with a depressed part 26 and a raised part 25 in a fixed side insert 22 and a movable side insert 23, respectively. In general, since the inserts 22 and 23 for forming plastic lens can be made small in size with a high degree of accuracy, the inserts 22 and 23 can be clearance fitted into the fixed side and movable side molds 20 and 21 with a radial tolerance of about 2mum, respectively, and slidably matched with a concentricity of about 3mum. Therefore, the inserts 22 and 23 can be directly matched by the raised part 25 and the depressed part 26 to attain a highly accurate positioning thereof. Accordingly, the concentric misalignment of optical inserts occurring in the conventional positioning by the use of a taper pin can be reduced from 10mum to at most 5mum, whereby the plastic lens can be formed with a high degree of accuracy. |
