| 摘要 |
PROBLEM TO BE SOLVED: To provide a lens that is molded by injecting a resin into a mold, wherein the occurrence of a molding defect is suppressed.SOLUTION: The lens (fθ lens 100) includes: a lens portion 110 having a pair of oblong surfaces opposite to each other, both of which are lens surfaces 111 and 112 having lens characteristic, wherein the cross-sectional area S1 of the lens portion 110 varies from a center toward both sides in a longitudinal direction of the lens; and rib portions 120 formed, at both sides in a shorter-side direction of the oblong surface (lens surface 111) of the lens portion 110, so as to extend along the longitudinal direction. A cross-sectional area S2 of the rib portion 120 varies in the longitudinal direction in such a manner that variations of the cross-sectional area (S1+S2×2), which includes the lens portion 110 and the rib portion 120, gradually decrease in the longitudinal direction. |
