Patent ID: 8587873

Claim:
A wide-angle projection lens comprising the following components in sequential order from a screen side: (a) a first lens group of negative refractive power; (b) a second lens group of positive refractive power; (c) a third lens group of positive refractive power; (d) a fourth lens group of positive refractive power; and at least one lens group has an aspheric surface; wherein 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; F 4 is the focal length of the fourth lens group; and ratios of the focal lengths are as follows: | F 1 /F|> 1.3; F 2 /F> 2; 1 <F 3 /F< 2; and 1.5 <F 4 /F< 8.