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1. (WO2002004889) INTERFEROMETRIC, LOW COHERENCE SHAPE MEASUREMENT DEVICE FOR A PLURALITY OF SURFACES (VALVE SEAT) VIA SEVERAL REFERENCE PLANES

Pub. No.:    WO/2002/004889    International Application No.:    PCT/DE2001/002519
Publication Date: Jan 17, 2002 International Filing Date: Jul 6, 2001
IPC: G01B 11/24
Applicants: ROBERT BOSCH GMBH
PRINZHAUSEN, Friedrich
LINDNER, Michael
THOMINET, Vincent
Inventors: PRINZHAUSEN, Friedrich
LINDNER, Michael
THOMINET, Vincent
Title: INTERFEROMETRIC, LOW COHERENCE SHAPE MEASUREMENT DEVICE FOR A PLURALITY OF SURFACES (VALVE SEAT) VIA SEVERAL REFERENCE PLANES
Abstract:
The invention relates to an interferometric shape measurement device for measuring the shape of a surface (A) of an object (BO). Said device comprises a beam source (KL) emitting a low coherence beam; a beam splitter (ST) for forming an object beam which is guided to the object (BO) by means of an object light path (OW); a reference beam which is guided to a reflecting reference plane (TS, SP1) by means of a reference light path (RW); an image converter (BW) for receiving the beam which is sent back by the surface (A) and the reference plane (TS, SP1) and which is brought to interference, and for directing said beam to an evaluation device which is used to determine a surface (A) measurement result. In order to evaluate the maximum interference by scanning, the optical length of the object light path (OW) is changed in relation to the optical length of the reference light path (RW), or an intermediate surface (A) image (ZA) which is produced in the object light path (OW) is scanned. A quick, precise measurement of spatially divided surfaces is obtained by arranging a superposition lens (FO; L1, L2; LB) in the object light path (OW) by means of which an image of at least one other surface (B), outside said surface (A), can be produced simultaneously; by arranging at least one other reference level (SP, SP2) in the reference light path (RW), corresponding to the number of other surfaces (B), in order to produce varying optical lengths in the reference light path (RW); and by the fact that the beam which is sent back by the at least one other surface (B) and the associated other reference plane, likewise brought to interference and scanned to evaluate the maximum interference, is likewise directed to the image converter, and evaluated in the evaluation device in order to determine the measurement result.