Patent ID: 8035821
Filing Date: 2011-10-11
Classification: G01B,G01N

Abstract:
1. An interferometric system, comprising: an illumination arm having a light source and an illuminating optical system to form an illuminating beam path; an object arm, having a reference element to measure an object, to form an image-ray path, the object to be measured having an object surface inaccessible to direct illumination; a reference arm; a detector arm having a detector; and a beam splitter; wherein the reference element has a first reference surface and at least one mirrored zone for measuring the object surface inaccessible to direct illumination, wherein the reference element has a second reference surface for measuring an object surface accessible to direct illumination, and wherein light beams are reflected by the object surface accessible to direct illumination as well as by the object surface inaccessible to direct illumination.