OPTICAL ASSEMBLY WITH SUPPRESSION OF DEGRADATION

• Main Authors: EHM DIRK HEINRICH, WALTER MARKUS, SCHMIDT STEFAN WOLFGANG
• Format: Patent
• Language: English; Korean
• Published: 04.04.2014
• Subjects: APPARATUS SPECIALLY ADAPTED THEREFOR; BASIC ELECTRIC ELEMENTS; CINEMATOGRAPHY; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; ELECTROGRAPHY; GAMMA RAY OR X-RAY MICROSCOPES; HOLOGRAPHY; IRRADIATION DEVICES; MATERIALS THEREFOR; NUCLEAR ENGINEERING; NUCLEAR PHYSICS; ORIGINALS THEREFOR; PHOTOGRAPHY; PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES,e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTORDEVICES; PHYSICS; SEMICONDUCTOR DEVICES; TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOTOTHERWISE PROVIDED FOR

An optical assembly including: a beam generating system generating radiation (6) at an operating wavelength, an optical element (13, 14) arranged in a residual gas atmosphere (16) and subjected to the radiation, which induces a degradation of a surface of the optical element, and a feed device feeding at least one gaseous constituent into the residual gas atmosphere, to suppress the degradation of the surface. Either a beam diameter (d) of the radiation at the surface of the optical element, lies above a threshold value (dc), thereby suppressing the degradation by the gaseous constituent, or, if the beam diameter (d) at the surface (14a) of the optical element (14) lies below the threshold value (dc) so that the effectiveness of the suppression of the degradation is reduced, at least one further device (25, 27) enhancing suppression of the degradation of the surface (14a) is assigned to the optical element (14).