Patent ID: 8437092

Claim:
An optical unit, comprising: a first lens that is a positive meniscus lens which is convex toward an object side; a diaphragm; a second lens having a positive power; a third lens having a negative power; a fourth lens having a positive, power; and a fifth lens having a negative power, wherein, the first lens, the diaphragm, the second lens, the third lens, the fourth lens, and the fifth lens are arranged in that order from the object side to an image plane side, the fifth lens has a first surface, a curvature radius of which satisfies the following conditional expression: −3≦ RL 5 S 1/ f≦− 0.05, where f represents a total focal length, and RL 5 S 1 represents the curvature radius of the first surface of the fifth lens, and the first surface of the fifth lens is spaced from the fourth lens along an optical axis.