Abstract: The disclosure provides a method and an apparatus for modifying imaging properties of a microlithographic optical system. In a method according to the disclosure, the imaging properties are modified by way of control signals coupled into the optical system by way of at least one interface. The values of the control signals that are in each case coupled in during the controlling for a desired modification of the imaging properties are ascertained on the basis of a model. The model is created by virtue of performing, in a learning phase in which the modification of the imaging properties that is in each case attained for different values of the control signals is ascertained, a successive individual adaptation of the model to the optical system. The learning phase is performed without prior specification of explicit information relating to internal mechanisms of action within the optical system.

Abstract: The disclosure provides a method and an apparatus for modifying imaging properties of a microlithographic optical system. In a method according to the disclosure, the imaging properties are modified by way of control signals coupled into the optical system by way of at least one interface. The values of the control signals that are in each case coupled in during the controlling for a desired modification of the imaging properties are ascertained on the basis of a model. The model is created by virtue of performing, in a learning phase in which the modification of the imaging properties that is in each case attained for different values of the control signals is ascertained, a successive individual adaptation of the model to the optical system. The learning phase is performed without prior specification of explicit information relating to internal mechanisms of action within the optical system.

Abstract: A position measuring system includes a first portion and a second portion, which can be moved relative to the first portion. The first portion has a material measure having a multiplicity of markings that are each able to assume two different values. A number m of directly successive markings codes a respective explicit absolute position along the material measure, and a number m?1 of directly successive markings does not code an explicit absolute position. The second portion has a scanning device having a number k of individual sensors for scanning a number n of directly successive markings. The scanning device is functionally connected to an evaluation device in order to ascertain the position of the second portion relative to the first portion. The condition n>m is satisfied, and the evaluation device is configured to recognize a scanning error in the scanning device.

Abstract: A position measuring system includes a first portion and a second portion, which can be moved relative to the first portion. The first portion has a material measure having a multiplicity of markings that are each able to assume two different values. A number m of directly successive markings codes a respective explicit absolute position along the material measure, and a number m?1 of directly successive markings does not code an explicit absolute position. The second portion has a scanning device having a number k of individual sensors for scanning a number n of directly successive markings. The scanning device is functionally connected to an evaluation device in order to ascertain the position of the second portion relative to the first portion. The condition n>m is satisfied, and the evaluation device is configured to recognize a scanning error in the scanning device.