| 摘要 |
In an imaging lens suitable for image reading of a four-lens element configuration comprising, successively from the object side, positive, positive, negative, and positive lenses, at least one surface of the fourth lens is made aspherical, whereby lighter weight and lower cost are achieved, while various kinds of aberration are corrected. The four-lens element imaging lens comprises, successively from the object side, positive first and second lenses L1 and L2 each having a surface on the object side convex toward the object side, a negative third lens L3 having a surface on the image side concave toward the image side, and a positive fourth lens L4 having at least one aspheric surface.
|
