| 摘要 |
PURPOSE: An illumination optical apparatus for an exposer is provided to improve a focusing efficiency by minimizing diverging light loss through a double light focusing mirror. CONSTITUTION: The illumination optical apparatus includes a light diverging unit and first and second light focusing units(60,70). The light diverging unit is located at the first focus(F1) and diverges light. The first light focusing unit is installed around the light diverging unit and focuses the diverged light on the second focus(F2). The second light focusing unit has an opening portion in the central portion thereof leading from the first light focusing unit to the second focus and is installed in the front of the first light focusing unit, focuses the light diverged from the light diverging unit at the first focus position and then focuses the diverged light at the second focus position through the first light focusing unit. The first light focusing unit is an elliptic mirror form and the second light focusing unit is a spherical mirror form.
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