| 摘要 |
An aspheric plastic lens comprises a spherical surface portion having upper and lower portions at the center thereof, the upper and lower portions having curved surfaces with a different curvature, respectively; a rib formed in a circular plate shape so as to extend from the peripheral edge of the spherical surface portion to the outside, the rib having burrs formed to project on the edges of the upper and lower surfaces thereof; and a pair of two-stage step portions formed on the upper and lower surfaces of the rib, the two-stage step portions being formed symmetrically with each other.
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