Multi-beam heterodyne laser doppler vibrometer
First Claim
1. A multi-beam heterodyne vibrometer for analyzing vibration of an object, the vibrometer comprising:
- an optical system for;
generating a plurality of object beams and a plurality of frequency-shifted reference beams, the plurality of frequency-shifted reference beams having a frequency that is shifted from a frequency of the plurality of object beams;
transmitting the object beams to the object, a portion of each of the object beams being reflected off of the object as a modulated object beam; and
collecting the modulated object beams; and
a combining element for combining each of the modulated object beams with a respective one of the frequency-shifted reference beams into a plurality of beam pairs.
1 Assignment
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Accused Products
Abstract
A multi-beam laser Doppler vibrometer simultaneously measures velocity, displacement, and vibration history of multiple locations on an object. A beam of coherent light is split into an object beam and a reference beam. The object beam is divided into a plurality of object beams to simultaneously illuminate multiple locations on the object under inspection. The reference beam is frequency shifted and split into a corresponding plurality of frequency-shifted reference beams. A portion of each object beam is reflected by the object as a modulated object beam. The plurality of modulated object beams are collected and respectively mixed with the plurality of frequency-shifted reference beams to provide a plurality of beam pairs. Each beam pair may be focused onto a photodetector or an optical fiber connected to a photodetector.
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Citations
70 Claims
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1. A multi-beam heterodyne vibrometer for analyzing vibration of an object, the vibrometer comprising:
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an optical system for; generating a plurality of object beams and a plurality of frequency-shifted reference beams, the plurality of frequency-shifted reference beams having a frequency that is shifted from a frequency of the plurality of object beams; transmitting the object beams to the object, a portion of each of the object beams being reflected off of the object as a modulated object beam; and collecting the modulated object beams; and a combining element for combining each of the modulated object beams with a respective one of the frequency-shifted reference beams into a plurality of beam pairs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 30, 31, 32)
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29. The vibrometer of the 28 wherein the output system includes a computer.
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33. A method for analyzing vibration of an object, the method comprising:
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transmitting a plurality of object beams to the object, a portion of each of the object beams being reflected by the object as a modulated object beam; collecting the modulated object beams; and combining each of the modulated object beams with a frequency-shifted reference beam. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58)
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59. A multi-beam heterodyne vibrometer for analyzing vibration of an object, the vibrometer comprising:
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a laser for providing an output beam; a first beam splitter for splitting the output beam into an object beam and a reference beam; a second beam splitter for splitting the object beam into a plurality of object beams for transmission to the object, a portion of each of the object beams being reflected by the object as a modulated object beam; a collecting lens for collecting the plurality of modulated object beams; a frequency shifter for shifting a frequency of the reference beam to yield a frequency-shifted reference beam; a third beam splitter for splitting the frequency-shifted reference beam into a plurality of frequency-shifted reference beams; a combining element for combining each of the modulated object beams with a respective one of the frequency-shifted reference beams into a plurality of beam pairs. - View Dependent Claims (60, 61, 62, 63, 64, 65, 66, 67, 68)
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69. A multi-beam heterodyne vibrometer for analyzing vibration of an object, the vibrometer comprising:
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an optical system for; generating coherent light; splitting the coherent light into an object beam and a reference beam; shifting the frequency of one of the beams; splitting the object beam into a plurality of object beams splitting the reference beam into a plurality of reference beams; transmitting the object beams to the object, a portion of each of the object beams being reflected off of the object as a modulated object beam; and collecting the modulated object beams; and a combining element for combining each of the modulated object beams with a respective one of the reference beams into a plurality of beam pairs. - View Dependent Claims (70)
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Specification