Patent ID: 6542316
Filing Date: 2003-04-01
Classification: G02B

Abstract:
A wide-angle projection lens, comprising the following components in sequential order from the enlarging side of the projection lens:a first lens group of negative refractive power, said first lens group including a cemented lens formed of a negative lens element that is cemented to a positive lens element, in that relative order from the enlarging side; a second lens group of positive refractive power that includes a lens element of positive refractive power; a diaphragm; and a third lens group of positive refractive power, said third lens group including a negative lens element that is cemented to a positive lens element; wherein the following Conditions (1)-(4) are satisfied âˆ’7.51/F5.02/F<9.5â€ƒâ€ƒCondition (2) 3.03/F<4.8â€ƒâ€ƒCondition (3) 2.83/Y<4.5â€ƒâ€ƒCondition (4) whereF is the focal length of the wide-angle projection lens, F1 is the focal length of the first lens group G1, F2 is the focal length of the second lens group G2, F3 is the focal length of the third lens group G3, and Y is the maximum image height.