Patent ID: 9195034
Filing Date: 2015-11-24
Classification: G02B,H04N

Abstract:
1. A lens for projection substantially consisting of three lens groups of: a first lens group having negative refractive power; a second lens group having positive refractive power; and a third lens group having positive refractive power in this order from a magnification side, wherein a reduction side is telecentric, and wherein the first lens group substantially consists of three lenses of an aspheric plastic lens that is made of plastic material and includes at least one aspherical surface and two negative lenses arranged in this order from the magnification side, and wherein the second lens group substantially consists of three lenses, and wherein the third lens group consists of a front group having negative refractive power and a rear group having positive refractive power arranged in this order from the magnification side with an air space therebetween, and wherein the front group substantially consists of two lenses of a negative single lens and a positive single lens arranged in this order from the magnification side with an air space therebetween, and the air space being narrower than the air space between the front group and the rear group, and wherein the following conditional formula (1) is satisfied: fFG f: a focal length of an entire system when projection distance is infinity.