Patent ID: 8760772

Claim:
A projection zoom lens comprising: a front lens group having negative refractive power and disposed adjacent to an object side of the projection zoom lens, the front lens group comprising: a first lens group having negative refractive power and disposed adjacent to the object side of the projection zoom lens; a second lens group having positive refractive power and disposed adjacent to an image side of the first lens group, wherein the second lens group is movable in order to compensate for a shift of a focal plane of the projection zoom lens; and a third lens group having positive refractive power and disposed adjacent to an image side of the second lens group; a rear lens group having positive refractive power and disposed adjacent to an image side of the projection zoom lens, the rear lens group comprising: a fourth lens group having negative refractive power and disposed adjacent to an image side of the third lens group; a fifth lens group having positive refractive power and disposed adjacent to an image side of the fourth lens group; and a sixth lens group having positive refractive power and disposed adjacent to the image side of the projection zoom lens; and an aperture stop disposed between the front lens group and the rear lens group, wherein the third lens group, the fourth lens group, and the fifth lens group move along an optical axis of the projection zoom lens to change an effective focal length of the projection zoom lens during zooming of the projection zoom lens.