Lens system for a projection display apparatus in which lenses are uniform in one direction and nonuniform in another

Abstract

In a projection type display apparatus that projects an image by inputting a light beam emitted from a light source to a spatial light modulation device, it is intended to provide a lens array as a component of an illumination optical system that is low in manufacturing cost, provides high screen illuminance, and enables miniaturization of the projection type display apparatus. The dimension of the cell lenses of a second lens array is not uniform in one of the row direction and the column direction. Since the cell lenses are rectangular when viewed from the front side, the second lens array can be manufactured with a metal mold having a simple shape. The boundary lines between the cell lenses are straight and level differences at the boundary lines are small, sink marks of the second lens array are small, and the efficiency of utilization of light beams is high. Further, since the dimension of the cell lenses is not uniform in the other of the row direction and the column direction, the corresponding dimension of the second lens array can be reduced.