| 摘要 |
A projection optical system is provided to reduce the shift of mirror elements and reduce light diameter of lenses by isolating the optical axis of each optical part to be inclined within a pupil plane. A projection optical system(100) comprises a first optical part(1), a second optical part(2), a third optical part(3), and a deflector(4). In the first optical part, one or more optical elements are formed. The first optical part projects the image which is income. The second optical part comprises an image-forming element and one or more optical elements. The second optical part forms the image. The formed image is emitted toward the first optical part. The pupil plane of the second optical part is located between the first and the second optical parts. The optical axis of the third optical part inclines to the optical axis of the second optical part. The deflector changes the pathway of the light coming out from the third optical part in order to turn toward the second optical part. |
