Patent ID: 7342723

Claim:
A portable projection system, comprising a housing; a handle coupled to the housing; and an optical engine, wherein the optical engine includes an illumination system; an imaging system; and a wide-angle projection lens comprising the following components in sequential order from an image side: a first lens group of negative refractive power, the first lens group having at least one aspheric surface; a second lens group; a third lens group of positive refractive power; and wherein the following Conditions (1) to (4) are satisfied: | F 1 /F|≧ 4.5 Condition (1) 2.5 ≦|F 2 /F|≦ 6.0 Condition (2) 3.8 ≦|F 3 /F|≦ 5.0 Condition (3) 0.8 ≦BFL/F≦ 1.4 Condition (4) 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; F 3 is the focal length of the third lens group; and BFL is the back focal length.