Patent ID: 9013812
Filing Date: 2015-04-21
Classification: G02B

Abstract:
1. An imaging lens comprising: a first lens group having negative refractive power; a stop; and a second lens group having positive refractive power, arranged in the order from an object side to an image plane side, wherein said first lens group includes a first lens having a strong concave surface facing the image plane side and negative refractive power; and a second lens having negative refractive power and a shape of a biconcave lens near an optical axis thereof, said second lens group includes a third lens having a biconvex shape and a lens group, said lens group is composed of a lens having positive refractive power and a lens having negative refractive power, and has negative refractive power as a whole, said first lens group has a focal length F1 and said second lens group has a focal length F2 so that the following conditional expression is satisfied: 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: