Patent ID: 7852487
Filing Date: 2010-12-14
Classification: G01B

Abstract:
1. A device for the optic measuring of an object ( 1 ), comprising a signal processing unit ( 2 ) as well as an interferometer with a light source ( 3 ) and at least one detector ( 4 a , 4 d ), the interferometer is embodied such that a light beam ( 12 ) created by the light source ( 3 ) is split at least into a working beam ( 12 a ) and a reference beam ( 12 b ), with the working beam ( 12 a ) adapted to impinge the object ( 1 ) and a measurement beam ( 12 a ) is reflected at least partially by the object and interfered by the reference beam ( 12 b ) on the detector ( 4 a , 4 d ), the interferometer comprises a heterodyne interferometer having a frequency shift unit ( 8 a , 8 d ), which is arranged in a beam path of at least one of the working beam ( 12 a ) or the reference beam ( 12 b ) and is adapted to shift a frequency of the working beam and the reference beam, the signal processing unit ( 2 ) is connected to the detector ( 4 a , 4 d ) and comprises a vibrometer processing unit ( 2 f ) comprises a heterodyne vibrometer evaluation unit, which is embodied to determine motion data of the object ( 1 ) from measuring signals of the detector ( 4 a , 4 d ) and also a direction of motion of the object ( 1 ), and the signal processing unit ( 2 ) is adapted to determine an intensity of the interference signal of the working beam ( 12 a ) and the reference beam ( 12 b ) from a carrier strength of the heterodyne signal of the detector, the light source ( 3 ) produces light with a coherence length shorter than 1 cm and that the device comprises a focus control ( 2 d ) and a device ( 11 ) for changing the optic path length ( 11 ) of the at least one of the working beam or the reference beam, controlled by the focus control, with the device for changing the optic path length ( 11 ) being arranged such that the optic path length of at least one of the working beam or the reference beam is changed via the device for changing the optic path length ( 11 ) depending on control signals of the focus control and the focus control controls the device for changing the optic path length such that the optic path lengths of the working beam and the reference beam are adjusted to each other.