| 摘要 |
<p>An illumination optical system for illuminating an object surface using light from a light source includes a condenser optical system (110) for directing the light from the light source to the object surface (IS), wherein the condenser optical system includes first and second optical systems, one of which forms a beam expander optical system (120) for varying a diameter of incident light, the beam expander being adapted to be movable as one element along an optical axis. <IMAGE></p> |
