The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 15, 2026
Filed:
Sep. 25, 2023
Carl Zeiss Smt Gmbh, Oberkochen, DE;
CARL ZEISS SMT GMBH, Oberkochen, DE;
Abstract
A measurement apparatus () for interferometrically measuring a shape of a surface () of a test object () in relation to a reference shape includes a diffractive optical element () generating a test wave () from measurement radiation (), whereas a wavefront of the test wave is adapted to a target shape of the surface of the test object and the target shape is configured as a first non-spherical surface, and a reference element () with a reference surface () having the reference shape, the reference shape being configured as a further non-spherical surface and the reference element including a low thermal expansion material with a mean coefficient of thermal expansion having an absolute value of no more than 200×10Kin the temperature range from 5 °C to 35 °C.