Measuring and testing – Vibration – Sensing apparatus
Patent
1985-05-08
1987-01-06
Birmiel, Howard A.
Measuring and testing
Vibration
Sensing apparatus
73643, 73655, 356358, G01N 2900
Patent
active
046337156
ABSTRACT:
The invention is concerned with a laser heterodyne interferometric method and system for measuring the displacement of a free surface of a material subjected to ultrasound. A laser beam having a predetermined intensity is generated and then divided into first and second beam portions having respective intensities representing minor and major fractions of the predetermined intensity, the first beam portion being angularly displaced relative to the second beam portion and being frequency shifted by a predetermined frequency. The second beam portion is passed through an optical lens off-center thereof to focalize the second beam portion onto the free surface of the material subjected to ultrasound, thereby scattering same. The scattered second beam portion is combined with the first beam portion to obtain an optical fringe signal which is converted into an electrical fringe signal comprising a central peak at the predetermined frequency and a sideband on either side of the central peak. The electrical fringe signal is thereafter processed through circuitry means without demodulating a phase modulation produced by ambient vibrations, to extract a signal proportional to the displacement of the free surface.
REFERENCES:
patent: 4180328 (1979-12-01), Drain
patent: 4313185 (1982-01-01), Chovan
patent: 4381676 (1983-05-01), Kaule et al.
patent: 4388832 (1983-06-01), Kaule
patent: 4512661 (1985-04-01), Claus
patent: 4581939 (1986-04-01), Takahashi
Birmiel Howard A.
Canadian Patents and Development Limited - Societe Canadienne de
LandOfFree
Laser heterodyne interferometric method and system for measuring does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Laser heterodyne interferometric method and system for measuring, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Laser heterodyne interferometric method and system for measuring will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-675497