SCANNING LENS, IMAGE SCANNER INCLUDING SCANNING LENS, AND IMAGE FORMING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a low-cost and small-size scanning lens having a wide filed-of-view, favorably correcting a field curvature, being bright, having an aperture efficiency of approximating to 100% to the peripheral part, correcting various aberrations, and being high contract in a high spatial frequency region.;SOLUTION: The scanning lens includes sequentially: a first group of a positive meniscus lens L1 with a convex surface facing an object side; s second group of a negative refractive power in which a positive meniscus lens L2 with a convex surface facing the object side and a negative meniscus lens L3 with the convex surface facing the object side are cemented; an aperture; a third group of a negative refractive power in which a negative lens L4 and a positive lens L5 are cemented; and a fourth group of a positive meniscus lens L6 with the concave surface facing the object side. The scanning lens satisfies appropriately set conditions.;COPYRIGHT: (C)2012,JPO&INPIT