Patent ID: 8009271
Filing Date: 2011-08-30
Classification: G02B,G03F

Abstract:
1. A projection optical system for forming an image of a first plane on a second plane, comprising: a first wedge prism each of an entrance surface and an exit surface of which has a plane and in which a predetermined first wedge angle is made between the plane of the entrance surface and the plane of the exit surface, wherein the first wedge prism is disposed within the projection optical system, when a coordinate system is defined so that a Z-axis direction is set along a direction of a normal to the first plane, an X-axis direction along a direction of an intersecting line between the plane of the entrance surface and the plane of the exit surface, and a Y-axis direction along a direction perpendicular to the Z-axis direction and the X-axis direction, the first wedge prism is arranged rotatably substantially around the Y-axis direction, and the first wedge prism transforms the image of the first plane imaged on the second plane from one of (1) a rectangular shape into a parallelogram shape and (2) a parallelogram shape into a rectangular shape.