Patent ID: 8760768
Filing Date: 2014-06-24
Classification: G02B,G03B

Abstract:
1. An optical projection system which, when an image is enlarged and projected on a surface, makes an aspect ratio of an image of an optical modulation device different from an aspect ratio of the image projected on the surface, the optical projection system comprising: a diaphragm which restricts a passage of light flux; and an optical modulation device side lens group which is arranged between the optical modulation device and the diaphragm, configured to include an adjustment optical device group which has different powers in a longitudinal direction and a lateral direction of the optical modulation device and which is capable of advancing and retracting on an optical path, and a rotationally symmetric lens group which includes one or more rotationally symmetrical lenses, which have same power in the longitudinal direction and the lateral direction of the optical modulation device and which is capable of advancing and retracting on the optical path, wherein, when one of the adjustment optical device group and the rotationally symmetric lens group of the optical modulation device side lens group is arranged on an optical path, a remaining group is withdrawn from the optical path, so that a state in which the adjustment optical device group is on the optical path can be interchanged with a state in which the rotationally symmetric lens group is on the optical path, and wherein, when it is assumed that a distance between a combined focus of the lateral section of the optical modulation device side lens group on a side of the surface to be projected on and an end surface on the side of the surface to be projected on is set to “FFPx” in a lateral section of the optical modulation device side lens group in the state in which the adjustment optical device group is arranged on the optical path, a distance between a combined focus of the longitudinal section of the optical modulation device side lens group on the side of the surface to be projected on and the end surface on the side of the surface to be projected on is set to “FFPy” in a longitudinal section of the optical modulation device side lens group in the state in which the adjustment optical device group is arranged on the optical path, and a distance between a combined focus of the optical modulation device side lens group on the side of the surface to be projected on and the end surface on the side of the surface to be projected on is set to “FFPL” in the optical modulation device side lens group in the state in which the rotationally symmetrical lens group is arranged on the optical path, FFPx, FFPy, and FFPL satisfy the following expressions,