Imaging optical unit for imaging an object field into an image field, and projection exposure apparatus including such an imaging optical unit

An imaging optical unit, comprising:

• a plurality of mirrors configured to guide imaging light from an object field in an object plane into an image field in an image plane along an imaging light beam path;
• and
• exactly one stop configured to define an entire outer marginal contour of a pupil of the imaging optical unit,
• wherein:
• the plurality of mirrors comprises first and second mirrors;
• the first mirror is configured so that, during use of the imaging optical unit, the imaging light is incident on the first mirror at an angle of incidence that is greater than 60°;
• the second mirror is configured so that, during use of the imaging optical unit, the imaging light is incident on the second mirror at an angle of incidence that is greater than 60°;
• in the imaging light beam path, the stop is in front of a penultimate mirror of the plurality of mirrors;
• the object field is spanned by a first Cartesian object field coordinate and a second Cartesian object field coordinate;
• a third Cartesian normal coordinate is perpendicular to both the first and second Cartesian object field co-ordinates;
• the imaging optical unit is configured so that, during use of the imaging optical unit:
• the imaging light extends in a first imaging light plane in which an imaging light main propagation direction lies;
• and
• the imaging light extends in a second imaging light plane in which the imaging light main propagation direction lies;
• the second imaging light plane is perpendicular to the first imaging light plane;
• a number of first plane intermediate images of the imaging light which extend in the first imaging light plane is different from a number of second plane intermediate images of imaging light which extend in the second imaging light plane.