Patent ID: 8995065
Filing Date: 2015-03-31
Classification: G02B

Abstract:
1. An imaging lens comprising: a first lens group; a second lens group having positive refractive power; and a third lens group having negative refractive power, which are arranged in order from an object side to an image side, wherein the first lens group includes a front lens group having a negative lens and disposed at the object side, a rear lens group having positive refractive power and disposed at the image side, and a diaphragm disposed between the front lens group and the rear lens group, wherein the second lens group consists of a second lens group first lens having negative refractive power, a second lens group second lens having positive refractive power, and a second lens group third lens having positive refractive power in an order from the object side, wherein, when focusing is performed, the second lens group is moved in an optical axis direction while the first lens group and the third lens group remain in a fixed, stationary state, wherein the imaging lens satisfies following Conditional Equation: wherein f1R: a focal length of the rear lens group, and f: a focal length of a whole lens system and wherein the front lens group includes at least a first front lens group lens and a second front lens group lens, the second front lens group lens includes a biconvex lens, the rear lens group includes a positive meniscus lens having a concave surface facing the object side, the second lens group first lens includes a biconcave lens having an aspheric surface formed on the object side and a second lens group second lens includes a biconvex lens with the second lens group first lens and the second lens group second lens configured as a cemented lens, the second lens group third lens includes a positive meniscus lens having aspheric surfaces formed on both surfaces thereof and the third lens group includes at least a biconcave lens.