Imaging lens

摘要

An imaging lens includes a first lens having negative refractive power; a stop; a second lens having positive refractive power; a third lens having negative refractive power; and a fourth lens having positive refractive power, arranged in the order from an object side to an image plane side. The first lens has an object-side surface and an image plane-side surface, curvature radii of which are both negative. The second lens has an object-side surface and an image plane-side surface, curvature radii of which are both positive. The third lens has an object-side surface and an image plane-side surface, curvature radii of which are both negative. The fourth lens has an object-side surface, a curvature of which is positive.

主权项

1. An imaging lens comprising:
a first lens having negative refractive power; a stop; a second lens having positive refractive power; a third lens having negative refractive power; and a fourth lens having positive refractive power arranged in this order from an object side to an image plane side, wherein said first lens is formed in a shape so that a surface thereof on the object side is concave and a surface thereof on the image plane side is convex, said second lens is formed in a shape so that a surface thereof on the object side is convex and a surface thereof on the image plane side is concave, said third lens is formed in a shape so that a surface thereof on the object side is concave and a surface thereof on the image plane side is convex, said fourth lens is formed in a shape so that a surface thereof on the object side is convex, and said first lens has a focal length f1 and said second lens has a focal length f2 so that the following conditional expression is satisfied:
−8.0