US 7,746,478 B2 · Method for interferometrically measuring an optical property of a test piece and a device suited for carrying out this method

Abstract

The invention relates to a method for interferometrically measuring large optics. A combination of a method known as stitching technique, during which the sub-interferograms are determined on partial surfaces of measuring area and are joined in a software-controlled manner and which, as a result, enables the use of small, more cost-effective interferometers, however polished surfaces of the test piece being assumed, together with an immersion method, during which, in fact, lower demands for the surface quality of the test piece exist that, however, is accompanied by edge faults. In order to make this combination possible, a modification of the stitching technique is developed, during which the measuring area (CA) is completely covered by a film consisting of an immersion liquid. A device a suited for carrying out this method is characterized by contact bodies, which are made of transparent material, rest upon the main surfaces of the test piece, and which completely cover the measuring area (CA), a film consisting of an immersion liquid being formed between the contact bodies and the main surfaces of the test piece.

Claims20

Dependent claims

A method for interferometric measurement of an optical characteristic of a measurement area of a specimen of transparent material having two opposing main surfaces, said method comprising:

(a) arranging the specimen in a measurement light beam of an interferometer such that the measurement light beam of the interferometer passes through the main surfaces of the specimen in a first surface portion of the measurement area, and performing a first interferometric measurement to obtain a first group of measurement data;
(b) arranging the specimen in the measurement light beam such that the measurement beam passes through the main surfaces of the specimen in a second surface portion of the measurement area which is offset from the first surface portion and overlaps therewith in an overlap region, and performing a second interferometric measurement to obtain a second group of measurement data;
(c) matching the measurement data of the first group of measurement data and the second group of measurement data using redundant information obtained in the overlap region for preparing a total interferogram on the measurement area,
wherein the measurement area is fully covered with immersion fluid film, which is formed between the main surfaces of the specimen and contact bodies of transparent material.

1 more element

Dependencies are inferred from the claim text.

Method for interferometrically measuring an optical property of a test piece and a device suited for carrying out this method

Life of this patent

Method for interferometrically measuring an optical property of a test piece and a device suited for carrying out this method

Life of this patent

Abstract

Claims20