| 摘要 |
<p>The present invention provides an image pickup lens with a large focal depth from the center to the outer part of an image plane formed on an image sensor and capable of maintaining its focal depth within a practical range and thus suppressing a decline in the resolution. An image pickup lens 7 includes, in order from the object side to the image plane side, an aperture stop 5, a first lens 1 that is a biconvex lens having positive power, a second lens 2 that is a meniscus lens having negative power and whose lens surface facing the object side is convex, a third lens 3 that is a meniscus lens having positive power and whose lens surface facing the object side is concave, and a fourth lens 4 that is a biconcave lens having negative power. The image pickup lens 7 includes a multifocal lens on the lens surface of the first lens 1 facing the object side. D and Ymax satisfy the following conditional expression (1): 0≰D/Ymax≰0.1 (1) where D is an absolute value of the distance between the multifocal lens surface and a surface of the aperture stop on the optical axis, and Ymax is the absolute value of the maximum image height on an image plane formed on the image sensor.</p> |
