Patent ID: 7637621

Claim:
A magnification projection optical system that guides a light beam from an image display panel to a screen in an upstream-downstream direction, projects the light beam from a direction inclined to a normal of the screen, and forms on the screen a magnified version of an image displayed on the image display panel, the magnification projection optical system comprising: a reflection optical system; and a transmission optical system, wherein the reflection optical system includes a plurality of reflecting surfaces having power and includes at least one rotationally asymmetric reflecting surface; the transmission optical system includes a transmitting surface having refractive power and includes at least one aspheric surface, and wherein a diaphragm is provided between a first surface of the transmission optical system from an upstream side thereof and a first surface of the reflection optical system from a downstream side thereof so that an image of the diaphragm is formed with negative reducing magnification by an optical element provided on a downstream side of the diaphragm.