Measuring module for determining the position of a component in an optical system for microlithography

Abstract

A measuring module for determining the position of a component in a microlithographic optical system comprises: a first optical resonator for distance measurement by irradiating a first measurement target associated with the component with a first measurement beam; and a second optical resonator for distance measurement by irradiating a second measurement target associated with the component with a second measurement beam. The optical resonators are configured to radiate the two measurement beams onto the corresponding measurement target from different directions.

Dependencies are inferred from the claim text.