| 摘要 |
<p>The purpose of this invention is to provide a high-performance imaging lens using a small number of unit lenses. Said imaging lens (10) has an aperture stop (S) and is used to form an image of a subject on a photoelectric conversion section of an imaging element (51). Within an effective region through which light rays pass, at least one lens surface (the image-side surface (S32) of a third unit lens (L3)) among the surfaces of first through third unit lenses (L1 through L3) is aspheric and is divided, by concentric circles centered on an optical axis (AX), into a plurality of surface regions (AR1, AR2, AR2). The height differences at the boundaries (TR1, TR2) between said surface regions (AR1, AR2, AR3) are no more than 0.1 µm. Adjacent surface regions (AR1, AR2, AR3) are represented by different aspheric-surface equations, and the lens surface satisfies relation (1). (1) 0.05 < |DS/SI| < 3.0 In relation (1), DS represents the distance along the optical axis (AX) between the abovementioned divided aspheric surface and the aperture stop (S), and SI represents the distance along the optical axis (AX) between the aperture stop (S) and the imaging plane (I).</p> |
