Optical system and method for improving imaging properties thereof

A method for improving imaging properties of an optical system comprising at least two optical elements whose spatial relation with respect to each other is configurable be changed, wherein at least one of the optical elements comprise a plurality of optical components, said method comprising the following steps:

• a) individually measuring an image defect of each optical component,
• b) computing first target positions for the plurality of optical components such than an overall image defect of the at least one of the optical elements is below a predetermined threshold value;
• c) measuring an overall image defect of the optical system, wherein the at least two optical elements are subjected to the measuring light;
• d) representing the measured overall image defect as a linear combination of base functions of an orthogonal function set;
• e) changing the spatial relation of the at least two optical elements;
• f) repeating steps c) and d), thereby obtaining a new linear combination of the base functions of an orthogonal function set;
• g) calculating second target positions for the at least two optical elements so as to reduce the overall image defect;
• h) moving the at least two optical elements to the second target positions.

A method for improving imaging properties of an optical system comprising at least two optical elements whose spatial relation with respect to each other is configurable to be changed, wherein at least one of the optical elements comprise a plurality of optical components, said method comprising the following steps:

• a) individually measuring a deviation from a design specification of at least one optical component whose manufacture has not been finished,
• b) computing a first target position for the at least one optical component such that an image defect caused by the deviation measured in step a) is below a predetermined threshold value;
• c) finishing the manufacture of the at least one optical component;
• d) assembling the at least one optical element with the at least one optical component being in the first target position;
• e) measuring an overall image defect of the optical system, wherein the at least two optical elements are subjected to the measuring light;
• f) representing the measured overall image defect as a linear combination of base functions of an orthogonal function set;
• g) changing the spatial relation of the at least two optical elements;
• h) repeating steps e) and f), thereby obtaining a new linear combination of the base functions of an orthogonal function set;
• i) calculating second target positions for the at least two optical elements so as to reduce the overall image defect;
• j) moving the at least two optical elements to the second target positions.

An optical system, comprising:

• a) at least two optical elements whose spatial relation with respect to each other is configurable to be changed,
• b) measuring means for measuring an overall image defect of the optical system, said measuring means being configured to direct measuring light through the optical system such that the at least two optical elements are subjected to the measuring light,
• c) a correcting optical element for correcting an image defect, wherein the correcting optical element has at least two distinct configurations,
• d) computing means for
• representing the optical effort of the correcting optical element in the at least two distinct configurations as linear combination of base functions of an orthogonal function set,
• representing the measured overall image defect as a linear combination of base functions of an orthogonal function set and,
• calculating a target position for the at least two optical elements and a configuration of the correcting optical element so as to reduce the overall image defects.

A method for improving imaging properties of an optical system comprising at least two optical elements and a correcting optical element having at least two distinct configurations, the method comprising the following steps:

• a) measuring an overall image defect of the optical system, wherein the at least two optical elements are subjected to measuring light;
• b) representing the measured overall image defect as a linear combination of base functions of an orthogonal function set;
• c) changing the spatial relation of the at least two optical elements;
• d) repeating steps a) and b), thereby obtaining a new linear combination of the base functions of an orthogonal function set;
• e) representing the optical effect of the correcting optical element in the at least two distinct configurations as linear combinations of base functions of an orthogonal function set;
• f) calculating, in a single optimization process, a target position for the at least two optical elements and a configuration of the correcting optical element so as to reduce the overall image defect;
• g) moving the at least two optical elements into the target position.