Patent · US Active

Compensation optical system for an interferometric measuring system

US11199396B2 · kind B2 · utility

0Cited by

3References

20Claims

0Family size

Assignee

Carl Zeiss SMT GmbH · DE

Inventors

Jochen Hetzler · Aalen, DE
Stefan Schulte · Marburg, DE

Key dates

Filing date	Mar 28, 2020
Grant date	Dec 14, 2021
Priority date	—
Expiry date	Mar 28, 2040

Classification

Technology area (CPC G)Physics
CPC primaryG01B2290/30
WIPO fieldMeasurement
WIPO sectorInstruments

Abstract

A compensation optical unit (30) for a measurement system (10) for determining a shape of an optical surface (12) of a test object (14) by interferometry generates a measuring wave (44), directed at the test object, with a wavefront that is at least partly adapted to a target shape of the optical surface from an input wave (18). The unit includes first (32) and second (34) optical elements disposed in a beam path of the input wave. The second optical element is a diffractive optical element configured to split the input wave into the measuring wave and a reference wave (42) following an interaction with the first optical element. At least 20% of a refractive power of the entire compensation optical unit is allotted to the first optical element, and this allotted refractive power has the same sign as the refractive power of the entire compensation optical unit.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.