Interferometric, low coherence shape measurement device for a plurality of surfaces (valve seat) via several reference planes

US6822746B2 · kind B2 · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Friedrich Prinzhausen · Stuttgart, DE
• Michael Lindner · Leutenbach, DE
• Vincent Thominet · Morges, FR

Key dates

• Filing date: Jul 24, 2002
• Grant date: Nov 23, 2004
• Expiry date: May 1, 2023

Classification

• Technology area (CPC G): Physics
• CPC primary: G01B11/2441
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An interferometric measuring device for measuring the shape of a surface of an object has a radiation source which emits a short-coherent radiation, a beam splitter for forming an object beam which is directed via an object light path to the object and a reference beam which is directed via a reference light path to a reflective reference plane. The interferometric measuring device also has an image converter which picks up the radiation that has been brought to interference and reflected back from the surface and the reference plane and sends it to an analyzing device for determining a measurement result pertaining to the surface. To analyze the interference peak by scanning, the optical length of the object light path is altered relative to the optical length of the reference light path, or an intermediate image of the surface produced in the object light path is scanned. A rapid and accurate measurement of spatially separated surfaces is achieved by situating a superposition optics in the object light path for producing simultaneously an image of the one surface and of at least one additional surface; at least one additional reference plane being situated in the reference light …