US Patent 7982978 Imaging lens

An imaging lens includes a first lens group that includes sequentially from an object side, a first lens formed of resin and having a positive refractive power and a second lens formed of resin and having a negative refractive power, the first lens and the second lens collectively forming a cemented lens having a positive refractive power. The imaging lens further includes a second lens group that includes a negative lens having a convex surface directed toward an image plane and a third lens group that includes a positive lens, where the first lens group, the second lens group, and the third lens groups are sequentially arranged from the object side.