Patent ID: 8104897

Claim:
A projection optical system comprising: a first optical part which projects an incident image; a second optical part including an image forming device which forms an image using a light and emits the image to the first optical part; a third optical part including at least one light source which emits the light; and a deflector which guides the light emitted from the third optical part toward the second optical part, wherein an optical axis of the third optical part is angled toward an optical axis of the second optical part, and an optical axis of the first optical part and the optical axis of the second optical part are parallel to each other and separated from each other, wherein the optical axes of the first, second and third optical parts extend along respective paths of the light from the first, second and third optical parts, wherein a distance between the optical axis of the first optical part and the optical axis of the second optical part is between 2% and 50% of an incident pupil diameter of the second optical part, and wherein the optical axis of the third optical part extends through the first optical part.