Illumination optical unit for projection lithography

An illumination optical unit, comprising:

• a first mirror device configured to reflect and polarize light;
• a second mirror device configured to reflect the light, the second mirror device being downstream of the first polarization mirror device along a path of the light through the illumination optical unit, the second mirror device comprising:
• a ring-shaped out mirror basic body in the form of a ring-shaped supporting frame;
• and
• a plurality of mirror facets supported by the ring-shaped supporting frame;
• and
• a drive device configured to cause relative displacement of the first and second mirror devices between first and second relative positions,
• wherein:
• in the first relative position, a beam of the light has a first geometry after reflecting from the second mirror device;
• in the second relative position, the beam of the light has a second geometry after reflecting from the second mirror device;
• the second geometry is different from the first beam geometry;
• and
• the illumination optical unit a projection lithography illumination optical unit.

An illumination optical unit, comprising:

• a mirror device configured to reflect and polarize light, the polarization mirror device comprising:
• a supporting frame having a conical basic shape;
• and
• a plurality of mirror facets supported by the supporting frame, wherein the illumination optical tool is a projection lithography illumination optical tool.