Moire method and measuring system for measuring the distortion of an optical imaging system

US7019824B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Ulrich Wegmann · Oberkochen, DE
• Uwe Schellhorn · Aalen, DE
• Ralph Klaesges · Aalen, DE
• Joachim Stuehler · Aalen, DE

Key dates

• Filing date: Sep 8, 2004
• Grant date: Mar 28, 2006
• Expiry date: Sep 8, 2024

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/706
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

In the case of a method and a measuring system for measuring the distortion of an optical imaging system with the aid of moiré patterns, an object grating with an object pattern is arranged in the object plane of the imaging system, and an image grating with an image pattern is arranged in the image plane of the imaging system. Both the object pattern and the image pattern in each case have a multiplicity of cells with sub-gratings of different grating properties, it being possible, in particular, for the sub-gratings to have different directions of periodicity and different phase angles. The object pattern and the image pattern are coordinated with one another in such a way that, when the object pattern is projected onto the image pattern with the aid of the imaging system, images of the sub-gratings of the object pattern superimpose in each case with assigned sub-gratings of the image pattern, accompanied by the generation of moiré sub-patterns, which are likewise present in the form of cells situated next to one another. As a result, it is possible simultaneously to determine distortion components for a plurality of image directions aligned transverse to one another. It is prefe…