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:
Mar. 22, 1977
Filed:
Aug. 20, 1975
Michel Eric Philbert, Paris, FR;
Abstract
Method and apparatus for monitoring the vibratory displacements of a diffusing or reflecting solid body which in a preferred application is a turbine blade. A laser source of rectilinearly polarized monochromatic light provides a laser beam which is directed at the solid body. The beam reflected off the body is directed toward a first photocell with a photomultiplier along with part of the incident laser beam. Part of the reflected beam is directed toward a second photocell with a photomultiplier. A Kerr or Pockels cell varies the intensity of the laser beam in response to the output current strength from the second photocell to maintain the lighting of the first photocell constant regardless of the presence of speckle phenomenon. Apertures are arranged in front of the photocells and sufficiently small, e.g. one tenth the diameter of the grains of materials of the solid body, so that the lighting of the first photocell may be considered constant at all points. A pulse counter is arranged after the first photomultiplier, and an inverter is disposed between the second photomultiplier and the Kerr or Pockels cell.