Imaging optical unit for imaging an object field into an image field

US11119413B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Johannes Ruoff · Aalen, DE
• Susanne Beder · Aalen, DE
• Hans-Juergen Rostalski · Oberkochen, DE
• Alexander Wolf · Oberkochen, DE

Key dates

• Filing date: Mar 17, 2020
• Grant date: Sep 14, 2021
• Expiry date: Mar 17, 2040

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/70316
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

An imaging optical unit includes a plurality of mirrors to guide imaging light along an imaging beam path. The plurality of mirrors includes a number of mirrors for grazing incidence (GI mirrors), which deflect a chief ray of a central object field point with an angle of incidence of more than 45°. At least two of the GI mirrors are in the imaging beam path as basic GI mirrors so that the deflection effect thereof adds up for the chief ray. At least one further GI mirror is arranged in the imaging beam path as a counter GI mirror so that the deflection effect thereof acts in subtractive fashion for the chief ray in relation to the deflection effect of the basic GI mirrors. This can yield an imaging optical unit having enhanced flexibility in relation to an installation space used for mirror bodies of the mirrors of the imaging optical unit.