The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 06, 1992
Filed:
May. 17, 1990
Roland Keck, Dusseldorf, DE;
Bertold Kruger, Krefeld-Fischeln, DE;
Abstract
The invention relates to a process and a device for the interferometric detection of surface displacements of solids, particularly in test material which is excited with ultrasonic waves, in which an illumination laser 10 radiates the test material surface 2, and a portion of the reflected light, after passing through a differing optical path length, is brought into a state of interference, while the interference is identified by an installed detector 9. In arrangements of this type known to the prior art, a very expensive apparatus and control system is needed to assure that demodulation of the reflected laser light is performed with maximum sensitivity. This is improved by the invention in that a joint illumination laser 10 is employed to operate several interferometer equipped with waveguides 5, 7, which in bundled fashion terminate in a common transmitter and receiver lens 4 positioned at a distance from the test material, from which lens detector-waveguides also emerge; here allocations which are dependent on the phase relation arise and whose signals are at the least added quantitatively and are employed to identify the ultrasonic events.