| 摘要 |
PROBLEM TO BE SOLVED: To provide a projection optical system by which chromatic aberration correction and the suppression of radiation fluctuation are excellently performed while maintaining design performance even in the case of using a laser beam source in which the narrowing of a band is not attained. SOLUTION: This projection optical system incorporates a lens component formed of fluorite and a lens component formed of quartz, and projects the image of a first face on a second face. The optical system has a first lens group including at least one lens component formed of fluorite and having positive refracting power, a second lens group arranged in an optical path between the first lens group and the second face and having negative refracting power, and a third lens group arranged in an optical path between the second lens group and the second face and having positive refracting power. When the number of pieces of the lens component formed of the quartz is Snum, that of the lens component formed of the fluorite is Cnum, and the numerical aperture of the projection optical system on the side of the second face is NA, relations Snum>Cnum and NA>0.75 are satisfied. |
