| 摘要 |
PROBLEM TO BE SOLVED: To easily and well perform the adjustment to correct the deviation of an imaging magnification and the adjustment of the imaging magnification according to the elongation and contraction of a substrate while well maintaining aberrations and improving productivity by forming an optical system to a symmetric shape around a diaphragm and moving the second and third lens groups disposed in the corresponding positions before and behind the diaphragm in magnification adjustment. SOLUTION: In the projection optical system for projecting mask patterns onto a work, a positive first lens group G<SB>1</SB>for making a luminous flux telecentric, the second lens group G<SB>2</SB>having a magnification adjusting function and imaging function, the diaphragm 1, the third lens group G<SB>3</SB>having the magnification adjusting function and imaging function, and a positive fourth lens group G<SB>4</SB>for making the luminous flux telecentric are arrayed successively from an object side, and the system is formed in a symmetric shape across the diaphragm 1 as a whole of the lens system. COPYRIGHT: (C)2004,JPO |
