| 摘要 |
PROBLEM TO BE SOLVED: To provide a lighting system which has a laser beam source, a plural beam source forming means and a re-imaging optical system and is capable of making numerical aperture (NA) of the aligner higher with less sheets of lenses and a smaller scale of composition while allowing the re-converged position where the optical energy density becomes high to exist outside the lens. SOLUTION: The lighting optical system is provided with a first lens group having a positive power, a second lens group having a negative power and a third lens group having a positive power in order from the incident light side. Further, a concave lens is arranged on the light emission side of the second lens group, a convex lens is arranged on the light incident side of the first lens group and, thereby, the position of the intersection point where a principal ray of an off-axial luminous flux intersects with the optical axis is allowed to exist between the second lens group and the third lens group. COPYRIGHT: (C)2005,JPO&NCIPI
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