Patent ID: 7821725

Claim:
An image pickup lens comprising, in order from an object side thereof: a first lens block with a positive refractive power, comprising a first lens substrate being a parallel flat plate, and lens portions 1 a and 1 b having a positive or negative refractive power, arranged on an object side surface and an image side surface of the first lens substrate, and being different from the first lens substrate in at least one of a refractive index and an Abbe number; and a second lens block with a positive or negative refractive power, comprising a second lens substrate being a parallel flat plate, and lens portions 2 a and 2 b having a positive or negative refractive power, arranged on an object side surface and an image side surface of the second lens substrate, and being different from the second lens substrate in at least one of a refractive index and an Abbe number, wherein the lens portion 1 a is arranged on the object side surface of the first lens substrate, an object side surface of the lens portion 1 a is a convex surface facing the object side, the lens portion 1 b is arranged on the image side surface of the first lens substrate, an image side surface of the lens portion 1 b is a concave surface facing an image side, the lens portion 2 a is arranged on the object side surface of the second lens substrate, an object side surface of the lens portion 2 a is a convex surface facing the object side, the lens portion 2 b is arranged on the image side surface of the second lens substrate, an image side surface of the lens portion 2 b is a concave surface facing the image side, and the image pickup lens satisfies the following expressions: 0.4< f 1 a/f< 0.9, and −3.0< f 2 b/f<− 0.5, where f1a is a focal length of the lens portion 1 a in an air, f2b is a focal length of the lens portion 2 b in the air, and f is a composite focal length of a total system of the image pickup lens.