Projection lens and projection system

Abstract

A projection lens enlarges and projects optical images in a matrix type light valve onto a screen. The projection lens includes a front lens group of the retrofocusing type; a rear lens with aspherical surfaces whose radii of curvature in the peripheral portion are shorter than that in the central portion; and a reflecting mirror which is positioned between the front lens group and the rear lens and diverts the optical axis. This projection lens enables the optical images in the light valve to be projected with a high contrast and a wide field angle. A projection system is provided which includes a light source; a light valve; a converging optical apparatus; a transmission type screen; diverting place mirrors; and a projection lens to enlarge and project the optical images in the light valve onto the screen. Since the projection lens has a wide field angle and has the reflecting mirror provided therein, the projection system can be very compact.