Multi-point vibration measurement device

Abstract

A multipoint vibration measuring device is capable of performing multipoint vibration measurement with high accuracy. In a multipoint vibration measuring device, an optical multiplexing / demultiplexing head receives measurement light L from a light source. S and a light multiplexing / demultiplexing optical system 131 including a light splitting element 131A connected to an interference optical system 120 to which the measurement light L is input and a light multiplexing element 131B connected to the interference optical system 120. S a projection optical system 133 for irradiating a plurality of points on a measurement surface 5 of a measurement target with the frequency components of each optical comb; S The frequency components of each optical comb included in the S and a combining optical system 132 that inputs the frequency components of the optical combs to the optical combining element 131B.

Claims

1. a light source that outputs a coherent measurement light and a reference light, the measurement light and the reference light having a spectrum with a predetermined frequency interval; an optical multiplexing / demultiplexing head for dividing the measurement light output from the light source into frequency components and irradiating each frequency component onto a plurality of points on a measurement surface of a measurement object; an interference optical system which receives the measurement light and the reference light output from the light source, inputs the measurement light input from the light source to the optical multiplexer-demultiplexer head, and causes the measurement light including the frequency components reflected on the measurement surface and returning via the optical multiplexer-demultiplexer head to interfere with the reference light output from the light source, thereby outputting an interference light for measurement; a measurement light detection unit that receives the measurement interference light obtained by the interference optical system and converts it into an electrical signal to obtain a measurement interference signal; a signal processing unit that analyzes vibration information at a plurality of points on the measurement surface based on the measurement interference signal obtained by the measurement light detection unit; It consists of: The optical multiplexing and demultiplexing head is characterized in that it comprises an optical demultiplexing element that demultiplexes each frequency component contained in the measurement light input from the interference optical system, a projection optical system that irradiates each frequency component demultiplexed by the optical demultiplexing element onto multiple points on the measurement surface of the object to be measured, an optical multiplexing element that multiplexes each frequency component of the measurement light reflected and returned from the measurement surface and inputs it to the interference optical system, and a combination optical system that inputs each frequency component contained in the measurement light demultiplexed by the optical demultiplexing element to the projection optical system and inputs each frequency component of the measurement light reflected and returned from the measurement surface to the optical multiplexing element.

2. the interference optical system outputs the measurement interference light, and also outputs reference interference light by causing the measurement light and a reference light input from the light source to interfere with each other; a reference light detection unit that receives the reference interference light obtained by the interference optical system and converts it into an electrical signal to obtain a reference interference signal, The multi-point vibration measuring device according to claim 1, characterized in that the signal processing unit analyzes vibration information at multiple points on the measurement surface based on the measurement interference signal obtained by the measurement light detection unit and the reference interference signal obtained by the reference light detection unit.

3. The multi-point vibration measuring device according to claim 1 or 2, characterized in that the optical multiplexing head separates each frequency component contained in the measurement light into one frequency component by the optical multiplexing element, irradiates each frequency component onto multiple points on the measurement surface of the object to be measured via the projection optical system, and multiplexes each frequency component of the measurement light reflected and returned from the measurement surface by an optical multiplexing element.

4. The multi-point vibration measuring device according to claim 1 or 2, characterized in that the optical multiplexing head separates each frequency component contained in the measurement light into multiple frequency components using the optical multiplexing element, irradiates each frequency component onto multiple points on the measurement surface of the object to be measured via the projection optical system, and multiplexes each frequency component of the multiple frequency components of the measurement light reflected and returned from the measurement surface using an optical multiplexing element.

5. 3. The multipoint vibration measuring device according to claim 1, wherein the coupling optical system is built into the projection optical system.

6. The optical splitter element splits each frequency component contained in the measurement light input from the interference optical system through one optical fiber and outputs the splitted signal through a plurality of optical fibers, and the optical combiner element combines each frequency component input through a plurality of optical fibers and outputs the combined signal through a single optical fiber; The multi-point vibration measuring device according to claim 5, characterized in that the combining optical system includes a combining optical element that aligns the optical axes of two light beams having orthogonal polarization directions output from two optical fibers.

7. 7. The multipoint vibration measuring device according to claim 6, wherein the coupling optical element is made of a birefringent crystal.

8. 7. The multipoint vibration measuring device according to claim 6, wherein the coupling optical element is a Wollaston prism.

9. The multi-point vibration measuring device described in claim 6, characterized in that the coupling optical system is composed of a coupling optical element array in which the coupling optical elements are arranged two-dimensionally, and each frequency component of the measurement light input through the coupling optical element array is focused by a focusing optical element and output toward the measurement surface of the measurement object, and each frequency component of the measurement light reflected and returned from the measurement surface is focused by the focusing optical element and input to the coupling optical element array.

10. 3. The multi-point vibration measuring device according to claim 1, wherein the measurement light and reference light output from the light source are reflected by the measurement surface and returned via the coupling optical system, and the measurement light and reference light containing the respective frequency components are interfered with in the interference optical system and output as interference light for measurement. A delay optical system is provided in the optical path through which the reference light passes, so that the optical path length of the optical path through which the measurement light and the measurement light containing the respective frequency components reflected by the measurement surface pass is made equal to the optical path length of the optical path through which the reference light passes.

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