| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical system having a diffraction optical device which can be applied to the optical system for which extremely high image-forming performance is required such as the projection optical system of a projection aligner for manufacturing a semiconductor especially by minimizing influence exerted on image-forming by generated unnecessary diffracted light in the optical system using a diffraction optical device. SOLUTION: In this optical system having the diffraction optical device, the diffraction optical device is constituted so that a part of or most of the unnecessary diffracted light not used for projecting an image may not enter the range of the projected image.
|
