| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a lens having two-stage step portions formed on upper and lower surfaces of a rib of the lens, and mold for manufacturing the same. <P>SOLUTION: An asymmetric plastic lens 10 provided with step portions includes: a spherical surface portion 11 which has upper and lower portions at the center formed into curved surfaces different by curvature; a rib 12 which is formed like a circular plate so as to extend from the peripheral edge of the spherical surface portion to the outside and has burrs 14 different by height projected on edges of upper and lower surfaces thereof; and a pair of two-stage step portions 13 formed symmetrically on the upper and lower surfaces of the rib. Poor placing inside a lens barrel, which is caused by the burrs formed on the upper and lower surfaces of the rib of the lens by the clearance formed at the coupling interface between a pin core 21 and a support core 25 of the mold, is improved, so that it is possible to significantly enhance a production yield of a lens unit forming an optical system. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
