OPTICAL PROJECTION SYSTEM AND IMAGE PROJECTOR INCORPORATING THE SAME

摘要

An optical projection system enlarges an image on an image display element and projects the enlarged image onto a screen. The system includes the image display element, a first optical system including lens groups arranged in order from an image display element side, a lens barrel holding the lens groups, and a free-form surface lens rotationally asymmetric and made from plastic, and a second optical system including a curved mirror disposed after the first optical system, wherein the free-form surface lens is formed to decrease in thickness from an intersection point between a surface of the free-form surface lens and an optical axis of the first optical system to an outer periphery of the lens along a line extending to the outer periphery.

主权项

1. An optical projection system to enlarge an image on an image display element and project the enlarged image onto a screen, comprising:
the image display element; a first optical system including lens groups arranged in order from an image display element side, a lens barrel holding the lens groups, and a free-form surface lens rotationally asymmetric and made from plastic; and a second optical system including a curved mirror disposed after the first optical system, wherein the free-form surface lens is formed to have a thickness which decreases from an intersection point between a surface of the free-form surface lens and an optical axis of the first optical system to an outer periphery of the lens along a line extending to the outer periphery.