Patent ID: 7123426

Claim:
A wide-angle projection lens comprising: (a) a first lens group of negative refractive power, the first lens group having at least one aspheric surface; (b) a second lens group of substantially zero refractive power and wherein an aperture stop lies within or near the second lens group; and (c) a third lens group of positive refractive power; wherein the following Conditions (1) to (3) are satisfied: | F 1 /F|< 4.0 Condition (1) |F 2 /F|> 50 Condition (2) | F 3/ F|< 3.5 Condition (3) where F is the focal length of the wide-angle projection lens; F 1 is the focal length of the first lens group; F 2 is the focal length of the second lens group; and F 3 is the focal length of the third lens group, wherein the first lens group comprises a first and a second lens element, the second lens element including the aspheric surface at its second surface.