ASPHERICAL PLASTIC LENS AND MOLD FOR PRODUCING IT

摘要

An aspherical plastic lens and a mold for producing the same are provided to prevent the badness due to the tilt of the lens, and to improve the productivity of a lens unit of an optical system. An aspherical plastic lens(10) includes a spherical part(11) which has central upper and lower parts formed of curved surfaces of different curvatures; a disk type rib(12) which is extended to the outer side of the peripheral part of the spherical part and has a protruded burr(14) at the edge part of the upper and lower sides, and a two-stepped part(13) which is symmetrically formed at the upper side and lower side of the rib. The two-stepped part is composed of a first stepped part and a second stepped part from which the burr is protruded. The first stepped part is formed with the depth deeper than the height of the protruded burr of the second stepped part.