Optical multipoint measuring device

Abstract

To provide an optical multipoint measuring device capable of performing multipoint simultaneous measurement with high accuracy by one light source without using an optical scanner.SOLUTION: The frequency components included in the measurement light LS output from the light source 1 are demultiplexed into a plurality p (p is any integer) of frequency components by the optical multiplexing and demultiplexing element 3, and a plurality m (m is any integer) of measurement points on the measurement surface 5 of the measurement target are irradiated with the measurement light LS as a plurality m of measurement light beams lS (1), lS (2), lS (3),., lS (m) for each of the plurality p of frequency components. Simultaneous measurement is performed on a plurality of measurement points on the measuring surface 5 by using a combined measuring light beam LS ' obtained by the optical multiplexing and demultiplexing element 3 combining the plurality m of measuring light beams lS (1) ', lS (2) ', lS (3) ',., lS (m) ' for each of the plurality p of frequency components that are reflected and returned from the plurality m of measurement points on the measuring surface 5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical multipoint measurement device such as a multipoint rangefinder or a three-dimensional shape measurement device that optically measures the distance to a measurement object at multiple points. [Background technology]

[0002] Conventionally, there are known distance measurement devices that irradiate a measurement object with laser light and measure the distance to the measurement object using the light reflected from the measurement object, and optical measurement devices that measure the distance to the measurement object at multiple points or perform shape measurement by scanning the laser light irradiated onto the measurement object in two dimensions (see, for example, Patent Documents 1 and 2).

[0003] The present inventors have previously proposed an optical comb rangefinder, distance measurement method, and optical three-dimensional shape measurement device that can perform measurements with high accuracy and in a short time by detecting the interference light between reference light irradiated onto a reference surface and measurement light irradiated onto a measurement surface using a reference light detector, and detecting the interference light between the reference light reflected by the reference surface and the measurement light reflected by the measurement surface using a measurement light detector, and determining the difference between the distance to the reference surface and the distance to the measurement surface from the time difference between the two interference signals obtained by the reference light detector and the measurement light detector (see, for example, Patent Document 3).

[0004] In optical three-dimensional shape measurement devices, measurement light emitted from an optical comb rangefinder is irradiated onto the object to be measured via a scanning optical system such as a galvanometer mirror or polygon mirror that scans one or two dimensions, and the measurement light reflected by the object to be measured is returned via the scanning optical system by the optical comb rangefinder to obtain three-dimensional shape information of the measurement surface as distance information to the measurement surface.Therefore, an optical scanner with a telecentric optical system such as a telecentric f-θ lens is used to irradiate the measurement light onto the object to be measured from a direction perpendicular to a virtual plane near the object to be measured.

[0005] The present inventors have also previously proposed a vibration measuring device and a vibration measuring method in which a light source emits reference light and measurement light, which have spectra at a predetermined frequency interval and are phase-synchronized and coherent with each other, the measurement light emitted from the light source is incident on a spectroscopic head, the measurement light incident on the spectroscopic head is divided into frequency components and irradiated onto multiple measurement points on a measurement surface of a measurement object, the measurement light reflected on the measurement surface and incident via the spectroscopic head is made to interfere with the reference light emitted from the light source using an interference optical system, optical spectral components contained in the interference light obtained by the interference optical system are separated by a diffraction grating, and each separated spectral component is detected by a plurality of photodetectors, and vibration information at the multiple measurement points on the measurement surface is analyzed by a signal processing unit based on each detected spectral component, thereby making it possible to simultaneously measure vibration information and height information of a measurement object at multiple points (see, for example, Patent Document 4). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-17854 [Patent Document 2] Japanese Patent Publication No. 2021-175967 [Patent Document 3] Patent No. 5231883 [Patent Document 4] Patent No. 5363231 Summary of the Invention [Problem to be solved by the invention]

[0007] In optical scanners installed in conventional optical three-dimensional shape measurement devices, the curved surfaces of lenses and mirrors generally do not have perfectly equal distances on a virtual plane due to deviations from the ideal shape and the influence of refractive index, and the heights of the center and periphery of the field of view often differ, as seen in the curvature of field. Optical three-dimensional shape measurement devices equipped with optical scanners using ideal telecentric optical systems in which the main optical axis is parallel to the optical axis at any point in the optical system can measure a high-precision reference plane like a mirror and correct the height data of the measurement object without error using calibration data that makes the measured plane appear flat. However, in reality, the measurement light irradiated onto the measurement object via the optical scanner is slightly tilted with respect to the optical axis at each location due to deviations from the ideal curved surface and the influence of the wavelength dispersion of the material, resulting in a one- or two-dimensional distribution of the light, which causes errors in the measured distance.

[0008] Furthermore, the vibration measuring device and vibration measuring method previously proposed by the present inventors are capable of simultaneously measuring vibration information and height information of multiple points of an object to be measured without using an optical scanner. However, it is necessary to separate the optical spectral components contained in the interference light obtained by the interference optical system using a diffraction grating, and to detect each of the separated spectral components using multiple photodetectors, which poses the problem of a complex configuration of the detection unit that detects the interference light generated by the interference optical system.

[0009] Therefore, an object of the present invention is to provide an optical multi-point measurement device that can perform high-precision simultaneous multi-point measurement without using an optical scanner with one light source and without requiring a diffraction grating to separate the optical spectral components contained in the interference light obtained by the interference optical system.

[0010] Other objects of the present invention and specific advantages obtained by the present invention will become more apparent from the following description of the embodiments. [Means for solving the problem]

[0011] In the present invention, the frequency components contained in the measurement light output from the light source are separated into a plurality of frequency components, and the plurality of measurement points on the measurement surface of the object to be measured are irradiated with the plurality of measurement light beams for each of the plurality of frequency components. The plurality of measurement light beams for each of the plurality of frequency components that are reflected and returned from the plurality of measurement points on the measurement surface are combined to obtain a combined measurement light beam, and optically simultaneous measurement is performed on the plurality of measurement points on the measurement surface.

[0012] That is, the present invention is an optical multi-point measurement device comprising: a light source that outputs coherent measurement light and reference light having spectra with a predetermined frequency interval; an optical multiplexing / demultiplexing head that demultiplexes the frequency components contained in the measurement light output from the light source into a plurality of frequency components, irradiates the plurality of measurement points on a measurement surface of a measurement object to be measured as a plurality of measurement light for each of the plurality of frequency components, and combines the plurality of measurement light for each of the plurality of frequency components that are reflected and returned from the measurement surface; an interference optical system that receives the measurement light and reference light output from the light source, inputs the measurement light input from the light source to the optical multiplexing / demultiplexing head, and causes the combined measurement light that is reflected at a plurality of measurement points on the measurement surface and returned via the optical multiplexing / demultiplexing head to interfere with the reference light output from the light source, and outputs interference light for measurement; a measurement light detection unit that receives the interference light obtained by the interference optical system and converts it into an electrical signal to obtain an interference signal for measurement; and a signal processing unit that analyzes the interference signal for measurement obtained by the measurement light detection unit.

[0013] In the optical multi-point measurement device according to the present invention, the optical multiplexing and demultiplexing head may include an optical demultiplexing element that demultiplexes each frequency component contained in the measurement light input from the interference optical system into a plurality of frequency components; a projection optical system that irradiates a plurality of measurement points on the measurement surface of the object to be measured with a plurality of measurement light beams for each of the plurality of frequency components demultiplexed by the optical demultiplexing element; an optical multiplexing element that multiplexes the plurality of measurement light beams for each of the plurality of frequency components reflected and returned from the measurement surface and inputs them into the interference optical system; and a coupling optical system that inputs the measurement light beams demultiplexed by the optical demultiplexing element into 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.

[0014] Furthermore, in the optical multi-point measurement device according to the present invention, the optical demultiplexing element demultiplexes each frequency component contained in the measurement light input from the interference optical system through one optical fiber into a plurality of frequency components and outputs the plurality of measurement light beams for each of the plurality of frequency components through the plurality of optical fibers; the optical combining element combines the plurality of measurement light beams for each of the plurality of frequency components input through the plurality of optical fibers and outputs the combined optical system through one optical fiber; and the combining optical system can include a combining optical element that aligns the optical axes of two light beams whose polarization directions are orthogonal to each other and output from the two optical fibers.

[0015] Furthermore, the optical multipoint measurement device according to the present invention may be one in which the coupling optical system is built into the projection optical system.

[0016] In the optical multipoint measuring device according to the present invention, the coupling optical element may be made of a birefringent crystal.

[0017] In the optical multipoint measuring device according to the present invention, the coupling optical element may be a Wollaston prism.

[0018] Furthermore, the coupling optical system can be configured to consist of a coupling optical element array in which the coupling optical elements are arranged two-dimensionally, and to collect each frequency component of the measurement light input through the coupling optical element array with a focusing optical element and output it toward the measurement surface of the measurement object, and to collect each frequency component of the measurement light reflected and returned from the measurement surface with the focusing optical element and input it to the coupling optical element array. [Effects of the Invention]

[0019] In the present invention, the frequency components contained in the measurement light output from the light source are separated into a plurality of frequency components, and a plurality of measurement points on the measurement surface of the object to be measured are irradiated with the plurality of measurement light beams for each of the plurality of frequency components. The plurality of measurement light beams for each of the plurality of frequency components that are reflected and returned from the plurality of points on the measurement surface are combined to obtain a combined measurement light beam, which can be used to perform simultaneous measurement of a plurality of measurement points on the measurement surface. This provides an optical multi-point measurement device that can perform simultaneous multi-point measurement with high accuracy without using an optical scanner with one light source or requiring a diffraction grating that separates the optical spectral components contained in the interference light obtained by the interference optical system.

[0020] In the optical multipoint measurement device according to the present invention, the optical multiplexing and demultiplexing head comprises an optical demultiplexing element that demultiplexes each frequency component contained in the measurement light input from the interference optical system into a plurality of frequency components, a projection optical system that irradiates a plurality of measurement points on a measurement surface of a measurement object to be measured with a plurality of measurement light beams for each of the plurality of frequency components demultiplexed by the optical demultiplexing element, an optical multiplexing element that multiplexes the plurality of measurement light beams for each of the plurality of frequency components reflected and returned from the measurement surface and inputs them to the interference optical system, and a coupling optical system that inputs the measurement light beams 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, thereby achieving a combination of the functions of the optical demultiplexing element and the optical multiplexing element. By separately operating the functions, an optical path is separated into one that splits the measurement light output from the light source via the interference optical system into multiple frequency components of an optical comb contained in the measurement light and irradiates the multiple measurement points on the measurement surface of the object to be measured, and another optical path that combines the multiple frequency components reflected and returned from the multiple measurement points on the measurement surface and inputs them to the interference optical system, thereby preventing unnecessary reflection components from the optical splitter element that splits the light into the multiple frequency components from mixing into the interference light required for multi-point measurement.This eliminates measurement errors caused by unnecessary reflection components from various optical elements such as optical splitter / combiner elements provided in the optical path through which the measurement light passes that is irradiated to the measurement surface via the interference optical system, mixing into the interference light required for multi-point measurement, and enables highly accurate simultaneous multi-point measurement. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of an optical multipoint measurement device to which the present invention is applied. [Figure 2] FIG. 2 is a diagram illustrating the function of the optical multiplexing and demultiplexing element provided in the optical multiplexing and demultiplexing head in the optical multipoint measurement device. [Figure 3] FIG. 3 shows the results of measuring an optical comb demultiplexed into three frequency components by an optical multiplexing / demultiplexing optical element for 100 GHz WDM, using an optical spectrum analyzer. [Figure 4] FIG. 4 is a schematic diagram showing the configuration of an optical multipoint measurement device that measures the shape of the main rotor blades of an RC helicopter. [Figure 5] (A), (B), (C), and (D) in Figure 5 are figures showing shape information of the main rotor blades in the form of distance signal waveforms, with the amplitude being the distance to the underside of the main rotor blades measured by the optical multi-point measurement device, where (A) is the distance signal waveform when the main rotor blades are rotating horizontally, (B) is the distance signal waveform when the main rotor blades are rotating with an upward angle, (C) is the distance signal waveform when the main rotor blades are rotating with an upward angle, and (D) is the distance signal waveform when the main rotor blades are rotating with an increased rotation speed. [Figure 6] FIG. 6 is a schematic diagram showing another example of the configuration of an optical multipoint measuring device to which the present invention is applied. [Figure 7] 7A and 7B are diagrams explaining the functions of the optical demultiplexing element and the optical multiplexing element provided in the optical multiplexing / demultiplexing head in the optical multipoint measurement device. FIG. 7A shows the function of demultiplexing each frequency component of the optical comb contained in the measurement light into each frequency component of the optical comb by the optical demultiplexing element, and FIG. 7B shows the function of multiplexing each frequency component demultiplexed into each frequency component by the optical multiplexing element. [Figure 8] FIG. 8 is a schematic diagram showing an example of the configuration of an optical multipoint measurement device equipped with a projection optical head incorporating a coupling optical element to which the present invention is applied. [Figure 9]Figures 9(A) and (B) show an example of the configuration of a projection optical element used in the projection optical head with a built-in coupling optical element, where (A) is a schematic diagram showing the configuration of the projection optical element, and (B) is a front view of a two-core capillary provided in the projection optical element. [Figure 10] Figures 10(A) and (B) show another example of the configuration of the projection optical element used in the projection optical head with the built-in coupling optical element, where (A) is a schematic diagram showing the configuration of the projection optical element, and (B) is a front view of the two-core capillary provided in the projection optical element. [Figure 11] Figures 11(A) and (B) show an example of the configuration of a coupling optical element array, which is formed by two-dimensionally arranging multiple projection optical elements provided in a projection optical head with a built-in coupling optical element in an optical multi-point measurement device to which the present invention is applied, where (A) is a longitudinal side view of the coupling optical element array, and (B) is a longitudinal front view of the coupling optical element array. [Figure 12] FIG. 12 is a schematic diagram showing an example of the configuration of an optical multipoint measurement device in which the above-described coupling optical element array is provided in a coupling optical element built-in projection optical head. [Figure 13] FIG. 13 is a schematic diagram showing another example of the configuration of an optical multipoint measuring device to which the present invention is applied. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Common components will be described by using common reference numerals in the drawings. Furthermore, the present invention is not limited to the following examples, and can be modified as desired without departing from the spirit of the present invention.

[0023] FIG. 1 is a schematic diagram showing the configuration of an optical multipoint measurement device 10 to which the present invention is applied.

[0024] This optical multipoint measuring device 10 measures coherent measurement light L S and reference beam L R and a light source 1 that outputs measurement light LS and reference light 0L R and an interference optical system 2 into which the measurement light L is inputted from the light source 1 via the interference optical system 2. S the optical multiplexing / demultiplexing head 34 to which the measurement interference light and the reference interference light obtained by the interference optical system 2 are input, an interference light detection unit 6 to which the measurement interference light and the reference interference light obtained by the interference optical system 2 are input, and a signal processing unit 7 to analyze the measurement interference signal obtained by the measurement light detection unit 6.

[0025] The light source 1 emits linearly polarized measurement light L S The first optical comb generator (COMB1) 1A outputs a linearly polarized reference light L R and a second optical comb generator (COMB2) 1B that outputs FB using polarization-maintaining fiber (PMF). 12A ,FB 12B The first optical comb generator (COMB1) 1A and the second optical comb generator (COMB2) 1B are connected to the interference optical system 2 via the S and reference beam L R The intensity or phase of each is periodically modulated to generate two types of optical combs with different modulation frequencies.

[0026] Here, PMF is an optical fiber that utilizes the photoelastic effect and structural changes to generate birefringence, where the effective refractive index differs between the length and width of the core, thereby improving the polarization-maintaining characteristics of the transmitted light. 12A ,FB 12B may be a polarizing optical fiber that can propagate only one polarization, rather than a PMF.

[0027] The interference optical system 2 includes an optical fiber FB 12A Measurement light L through S is input, and the second optical comb generator (COMB2) 1B outputs the optical fiber FB 12B via the reference beam L R is entered.

[0028] The interference optical system 2 is an optical fiber FB using a PMF.2A1 ,FB 2A2 ,FB 2B1 ,FB 2B2 ,FB 2C Five optical couplers connected by OC A ,OC B ,OC C ,OC D ,OC E Optical coupler OC A Externally connected optical fiber FB 12A The measurement light L is emitted from the first optical comb generator (COMB1) 1A via S is input and the optical coupler OC B Externally connected optical fiber FB 12B Reference light L is generated from the second optical comb generator (COMB2) 1B via R is entered.

[0029] In this interference optical system 2, an optical coupler OC A There are two optical fiber FB 2A1 ,FB 2A2 Two optical couplers via OC D ,OC E Internally connected to the optical coupler OC B There are two optical fiber FB 2B1 ,FB 2B2 Two optical couplers via OC C ,OC D is internally connected, and the optical coupler OC E Optical fiber FB 2C via optical coupler OC C are internally connected.

[0030] The measurement light L input to the interference optical system 2 S is the optical coupler OC E Optical fiber FB using PMF externally connected to 23 and input to the optical multiplexing / demultiplexing element 3 of the optical multiplexing / demultiplexing head 34 via the optical multiplexing / demultiplexing element 3.

[0031] The optical multi-point measuring device 10 is a multi-point distance meter that irradiates a plurality of measurement points on a measurement surface 5 of a measurement object with measurement light and simultaneously measures the distances to the plurality of measurement points, and the optical multiplexing / demultiplexing head 34 is an optical fiber FB using m (m is an arbitrary integer) PMFs in the optical multiplexing / demultiplexing element 3. 341 ,FB 342 ,FB 343 ,···,FB 34m m projection optical heads 4 connected via (1) ,4 (2) ,4 (3) ,···,4 (m) Equipped with.

[0032] Here, FIG. 2 is a diagram illustrating the function of the optical multiplexing / demultiplexing element 3 provided in the optical multiplexing / demultiplexing head 34 in the optical multipoint measuring device 10. As shown in FIG.

[0033] That is, the optical multiplexer / demultiplexer 3 receives the measurement light L input from the light source 1 via the interference optical system 2. S The frequency components of the optical comb included in the measurement light L are demultiplexed into multiple p (p is an arbitrary integer) frequency components. S The multiple m measurement light beams l are obtained by dividing the multiple p frequency components into S(1) ,l S(2) ,l S(3) ,···,l S(m) is the m optical fibers FB 341 ,FB 342 ,FB 343 ,···,FB 34m The m projection optical heads 4 (1) ,4 (2) ,4 (3) ,···,4 (m) is entered into

[0034] In addition, the m projection optical heads 4 (1) ,4 (2) ,4 (3) ,···,4 (m) are the condenser lenses 4 A1 ,4 A2 ,4 A3 ,···,4 Am and quarter wave plate 4B1 ,4 B2 ,4 B3 ,···,4 Bm and a signal is transmitted from the optical multiplexer / demultiplexer 3 to the optical fiber FB 341 ,FB 342 ,FB 343 ,···,FB 34m The measurement light l is input through S(1) ,l S(2) ,l S(3) ,···,l S(m) The above focusing lens 4 A1 ,4 A2 ,4 A3 ,···,4 Am The light is collected by the quarter-wave plate 4. B1 ,4 B2 ,4 B3 ,···,4 Bm irradiated onto m measurement points on the measurement surface 5 of the measurement object through the 1 / 4 wavelength plate 4 B1 ,4 B2 ,4 B3 ,···,4 Bm The measurement light returning through l S(1) ',l S(2) ',l S(3) ',···,l S(m) 'The above focusing lens 4 A1 ,4 A2 ,4 A3 ,···,4 Am and the light is collected by the optical fiber FB 341 ,FB 342 ,FB 343 ,···,FB 34m The light is input to the optical multiplexer / demultiplexer element 3 via the optical multiplexer / demultiplexer element 3.

[0035] That is, the optical multiplexing / demultiplexing head 34 receives the measurement light L output from the light source 1. S The frequency components of the optical comb included in the S(1) ,l S(2) ,l S(3) ,···,l S(m) and a plurality of m measurement points on the measurement surface 5 of the measurement object are irradiated with the plurality of m measurement light beams l for each of the plurality of p frequency components, which are reflected by the measurement surface 5 and returned.S(1) ',l S(2) ',l S(3) ',···,l S(m) Measurement light L obtained by combining S ' the optical coupler OC of the interference optical system 2 E Enter.

[0036] In the optical multiplexing / demultiplexing head 34, the interference optical system 2 is connected to an optical fiber FB 23 The optical multiplexer / demultiplexer 3 connected via the interference optical system 2 receives the measurement light L from the light source 1. S The frequency components of the optical comb included in the signal are demultiplexed into a plurality of p (p is an arbitrary integer) frequency components, and a plurality of m measurement light beams l for each of the plurality of frequency components are obtained. S(1) ,l S(2) ,l S(3) ,···,l S(m) As a result, the m projection optical heads 4 (1) ,4 (2) ,4 (3) ,···,4 (m) irradiated onto m measurement points on the measurement surface 5 of the measurement object through the (1) ,4 (2) ,4 (3) ,···,4 (m) The plurality of m measurement light beams l for each of the plurality of frequency components are returned via S(1) ',l S(2) ',l S(3) ',···,l S(m) ' are multiplexed by the optical multiplexer / demultiplexer element 3, and the multiple m measurement beams l S(1) ',l S(2) ',l S(3) ',···,l S(m) Measurement light L S 'The above optical fiber FB 23 The optical coupler OC of the interference optical system 2 E Enter.

[0037] Here, the m projection optical heads 4 (1) ,4 (2) ,4 (3) ,···,4 (m) In the above optical coupler OCE Measurement light L output from S The measurement light l is irradiated onto the measurement surface 5 of the measurement object after splitting each frequency component of S(1) ,l S(2) ,l S(3) ,···,l S(m)) and the measurement light l reflected by the measurement surface 5 and returning S(1) ',l S(2) ',l S(3) ',···,l S(m) ' are the quarter wave plates 4 above, respectively. B1 ,4 B2 ,4 B3 ,···,4 Bm Therefore, the optical coupler OC E The measurement light l is input to S(1) ',l S(2) ',l S(3) ',···,l S(m) Measurement light L S ' polarization is above the optical coupler OC E Measurement light L output from S The polarization of the light is perpendicular to that of the light of the other polarizer.

[0038] The above optical coupler OC E functions as a polarized beam combiner / splitter (PBC / PBS; hereafter, a module that can be used for input and output via fiber is called a PBC module) 5, and splits the measurement light L S 'This optical coupler OC E From optical fiber FB 2C via optical coupler OC C is entered into

[0039] In the interference optical system 2, the measurement light l reflected by the measurement surface 5 S(1) ',l S(2) ',l S(3) ',···,l S(m) Measurement light L S The interference light between the reference light LR input from the light source 1 and the reference light LR is called the measurement interference light l S(1) ',l S(2) ',l S(3) ',···,l S(m)'As mentioned above, the optical coupler OC C and the measurement light L input from the light source 1. S and reference beam L R The interference light from the optical coupler OC D Output from

[0040] That is, the interference optical system 2 detects the measurement light L output from the light source 1. S and reference beam L R are input, and the measurement light L input from the light source 1 is S is input to the optical multiplexing / demultiplexing head 34, and the measurement light l is reflected at a plurality of measurement points on the measurement surface 5 and returns via the optical multiplexing / demultiplexing head 34. S(1) ',l S(2) ',l S(3) ',···,l S(m) Measurement light L S ' and the reference light L input from the light source 1. R The interference light for measurement is then output to the optical coupler OC C and the measurement light L input from the light source 1. S and reference beam L R The interference light from the optical coupler OC D Output from

[0041] The interference light detector 6, to which the measurement interference light and the reference interference light obtained by the interference optical system 2 are input, includes a measurement interference light detector 6A and a reference interference light detector 6B, each of which is a balanced photodetector. C Two optical fiber FBs externally connected to 26A1 ,FB 26A2 Through the above optical coupler OC C The measurement interference light detector 6A receives the measurement interference light input from the S and the optical coupler OC D Two optical fiber FBs externally connected to 26B1 ,FB 26B2 Through the above optical coupler OC DThe reference interference light detector 6B receives the reference interference light input from the reference interference light detector 6B, detects the reference interference light, and converts it into an electrical signal to generate a reference interference signal S R Output.

[0042] Then, in the signal processing unit 7, the measurement interference signal S obtained in the interference light detection unit 6 is S and the reference interference signal S R , and performs multi-point distance measurement processing up to a plurality of measurement points on the measurement surface 5. That is, the signal processing unit 7 calculates the phase of the measurement interference signal S obtained by the interference light detection unit 6. S By FFT analysis, the measurement light l S(1) ',l S(2) ',l S(3) ',···,l S(m) For each of the plurality of frequency components p included in ', the phase difference for each frequency component relative to the reference signal is calculated, thereby calculating each distance to the plurality of measurement points m on the measurement surface 5.

[0043] In this optical multipoint measuring device 10, measurement light L output from a light source 1 S The frequency components included in the S(1) ,l S(2) ,l S(3) ,···,l S(m)) and a plurality of m measurement points on the measurement surface of the measurement object are irradiated with the plurality of m measurement light beams l for each of the plurality of p frequency components, which are reflected and returned from the plurality of m measurement points on the measurement surface. S(1) ',l S(2) ',l S(3) ',···,l S(m) The combined measurement light L obtained by combining S By using the above-mentioned ', it is possible to simultaneously measure distances to multiple measurement points on the measurement surface, and it is possible to perform high-precision multi-point distance measurement with one light source 1 without using an optical scanner.

[0044] FIG. 3 shows the results of measuring, with an optical spectrum analyzer, an optical comb demultiplexed into three frequency components by an optical multiplexing / demultiplexing optical element for 100 GHz WDM.

[0045] FIG. 4 is a schematic diagram showing the configuration of an optical multi-point measurement device 10′ that uses this 100 GHz WDM optical multiplexing / demultiplexing optical element as the optical multiplexing / demultiplexing element 3 of the optical multiplexing / demultiplexing head 34 to measure the shape of the main rotor blade 61 of an RC helicopter 60.

[0046] In this optical multipoint measuring device 10′, p=3, and the measuring light L S Measurement light l is separated into three frequency components. S(1) ,l S(2) ,l S(3) The rotating main rotor blade 61 of the RC helicopter 60 was measured at three locations.

[0047] This optical multi-point measurement device 10' uses an optical demultiplexing / multiplexing optical element for 100 GHz WDM as the optical demultiplexing / multiplexing element 3 of the optical demultiplexing / multiplexing head 34 in the optical multi-point measurement device 10. In this optical multi-point measurement device 10', the same components as those in the optical multi-point measurement device 10 are given the same symbols, and detailed descriptions of them will be omitted.

[0048] That is, in this optical multipoint measuring device 10', in the optical multiplexing / demultiplexing head 34, the optical multiplexing / demultiplexing element 3 using the optical multiplexing / demultiplexing optical element for 100 GHz WDM demultiplexes the optical combs of the channels CH1, CH2, CH3, ..., into three frequency components of p=3 shown in FIG. 3, and for example, the optical combs CH1, CH2, and CH3 are used to separate the measurement light l S(1) ,l S(2) ,l S(3) Three projection optical heads input as 4 (1) ,4 (2) ,4 (3) were installed side by side to measure the surface shape of the main rotor blade 61 of the RC helicopter 60.

[0049] In the optical multiplexing / demultiplexing head 34, the measurement light LS(1), measurement light LS(2), and measurement light LS(3) separated by the optical multiplexing / demultiplexing optical element 3 are projected onto three projection optical heads 4. (1) ,4 (2) ,4 (3) The light is irradiated upward from the bottom of the rotating main rotor blade 61 at the outer circumferential position, the central position, and the inner circumferential position, and is reflected by the bottom surface of the rotating main rotor blade 61 and projected onto the three projection optical heads 4. (1) ,4 (2) ,4 (3) The above measurement light returns through l S(1) ',l S(2) ',l S(3) ' are multiplexed by the optical multiplexing / demultiplexing optical element 3, S(1) ',l S(2) ',l S(3) The measurement light L S ' is obtained.

[0050] The measurement light L obtained by the optical multiplexing and demultiplexing head 34 S ' is input to the interference optical system 2.

[0051] Then, in the signal processing unit 7, the measurement interference signal S obtained in the interference light detection unit 6 is S By FFT analysis, the measurement light l S(1) ',l S(2) ',l S(3) For each of the multiple p=3 frequency components of the optical comb included in ', the reference signal L R By calculating the phase difference for each frequency component relative to the above, the distances to the underside of the rotating main rotor blade 61 at the outer peripheral position, central position, and inner peripheral position can be simultaneously measured, thereby obtaining shape information of the main rotor blade 61.

[0052] Here, (A), (B), (C), and (D) in Figure 5 are figures showing shape information of the main rotor blade 61 in the form of a distance signal waveform whose amplitude is the distance to the underside of the main rotor blade 61 measured by the optical multi-point measurement device 10', where (A) is the distance signal waveform when the main rotor blade 61 is rotating horizontally, (B) is the distance signal waveform when the main rotor blade 61 is rotating with its angle changed upward, (C) is the distance signal waveform when the main rotor blade 61 is rotating with its angle changed downward, and (D) is the distance signal waveform when the main rotor blade 61 is rotating with its rotation speed increased.

[0053] That is, in the optical multipoint measuring device 10′, the measuring light L S(1) , measurement light L S(2) , measurement light L S(3) The interference light detector 6 receives and detects each of the measurement interference lights based on the reflected light from the main rotor blade 61. The shape information obtained in the signal processor 7 is expressed as a distance signal waveform S S(1) ,S S(2) ,S S(3) As shown in (A), (B), and (C) of FIG. 5, by changing the angle of the main rotor blade 61, the inclination of the streamlined shape of the underside of the main rotor blade 61 changes, and by increasing the rotation speed of the main rotor blade 61, the detection period of the underside of the main rotor blade 61 becomes shorter, as shown in (D) of FIG. 5.

[0054] Here, in the optical multipoint measuring device 10, the measurement interference signal S obtained by the interference light detecting unit 6 S The signal processing unit 7 performs FFT analysis on the measured light beams, thereby simultaneously measuring the distances to the measurement points of the plurality of meters on the measurement surface 5. The measurement interference light beams detected by the interference light detection unit 6 are the measurement light beams l of the plurality of meters that are reflected and returned from the measurement points of the plurality of meters on the measurement surface 5. S(1) ',l S(2) ',l S(3) ',···,l S(m)Measurement light L S ' and the reference beam L R The interference light is the multiple m measurement light l S(1) ',l S(2) ',l S(3) ',···,l S(m) ' is the measurement light L S The multiple frequency components of the optical comb included in are demultiplexed into multiple m for each multiple p frequency component, and each contains multiple p frequency components, so the multiple m measurement light l S(1) ',l S(2) ',l S(3) ',···,l S(m) By performing spectroscopic analysis on the ', it is also possible to examine the absorption, emission, scattering, etc. of light on the measurement surface.

[0055] That is, changes in the surface condition of the measurement surface, such as the roughness and fine structure of the measurement surface, affect the reflectance and reflection spectrum. S(1) ',l S(2) ',l S(3) ',···,l S(m) By performing spectroscopic analysis on the above, it is possible to evaluate changes in the surface condition of the measurement surface. For example, by using the measurement surface of the measurement object 5, in which multiple samples to be measured, such as gases, liquids, and solids, are arranged in an array as cells, as a reflecting surface, it is possible to automatically perform spectroscopic analysis of multiple samples.

[0056] FIG. 6 is a schematic diagram showing another example of the configuration of an optical multipoint measuring device to which the present invention is applied.

[0057] The optical multipoint measuring device 10A shown in FIG. S and reference beam L R and a light source 1 that outputs measurement light L S and reference beam L R and an interference optical system 2A into which the two optical fibers FB 23 ,FB 32an optical multiplexing / demultiplexing head 34A connected via an interference light detector 6 to which the measurement interference light and the reference interference light obtained by the interference optical system 2A are input; and a measurement interference signal S obtained by the interference light detector 6. S and the reference interference signal S R The signal processor 7 receives the signal.

[0058] This optical multipoint measuring device 10A is configured by replacing the optical multiplexing / demultiplexing head 34 in the optical multipoint measuring device 10 with an optical multiplexing / demultiplexing optical system 31 consisting of an optical multiplexing element 3A and an optical multiplexing element 3B, and m projection optical heads 4 (1) ,4 (2) ,4 (3) ,···,4 (m) In this optical multi-point measurement device 10A, the same components as those in the optical multi-point measurement device 10 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0059] The optical demultiplexing element 3A constituting the optical demultiplexing / multiplexing optical system 31 of the optical demultiplexing / multiplexing head 34A is an optical fiber FB 23 Through the interference optical system 2A optical coupler OC A The optical multiplexer 3B is connected to the optical fiber FB 32 The optical coupler OC of the interference optical system 2A is C is connected to.

[0060] The coupling optical system 32 of the optical multiplexing / demultiplexing head 34A is connected to the optical demultiplexing element 3A of the optical multiplexing / demultiplexing optical system 31 by m optical fibers FB 341 ,FB 342 ,FB 343 ,···,FB 34m and m optical fibers FB are connected to the optical multiplexing element 2B of the optical multiplexing / demultiplexing optical system 31 via 431 ,FB 432 ,FB 433 ,···,FB 43m m optical couplers OC1, OC2, OC3, . . . , OC m The m optical couplers OC1, OC2, OC3, . . . , OCm m optical fibers B 441 ,FB 442 ,FB 443 ,···,FB 44m m projection optical heads 4 of the projection optical system 33 (1) ,4 (2) ,4 (3) ,···,4 (m) is connected to.

[0061] The optical couplers OC1, OC2, OC3, . . . , OC m are the optical couplers OC in the optical multipoint measuring device 10. E It functions as a PBC module in the same way.

[0062] In the optical multiplexing / demultiplexing head 34A, the optical fiber FB 23 The measurement light L is input to the optical demultiplexing element 3A of the optical demultiplexing / multiplexing optical system 31 via the S is input, and the measurement light L S The multiple frequency components of the optical comb included in S(1) ,L S(2) ,L S(3) ,···,L S(m) The m optical couplers OC1, OC2, OC3, . . . , OC m m projection optical heads 4 of the projection optical system 33 (1) ,4 (2) ,4 (3) ,···,4 (m) is entered into

[0063] The projection optical head 4 of the projection optical system 33 (1) ,4 (2) ,4 (3) ,···,4 (m) are the condenser lenses 4 A1 ,4 A2 ,4 A3 ,···,4 Am and quarter wave plate 4 B1 ,4 B2 ,4 B3 ,···,4 Bm It consists of:

[0064] The projection optical head 4 of the projection optical system 33 (1) ,4 (2) ,4 (3) ,···,4 (m) The measurement light l input to S(1) ,l S(2) ,l S(3) ,···,l S(m) are the condenser lenses 4 A1 ,4 A2 ,4 A3 ,···,4 Am The light is collected by the quarter-wave plate 4 B1 ,4 B2 ,4 B3 ,···,4 Bm The light is irradiated onto a plurality of m measurement points on the measurement surface 5 of the object to be measured via the

[0065] Then, the measurement light l is reflected and returned from each measurement point on the measurement surface 5 of the measurement object. S(1) ',l S(2) ',l S(3) ',···,l S(m) ' is the projection optical head 4 (1) ,4 (2) ,4 (3) ,···,4 (m) The above quarter-wave plate 4 B1 ,4 B2 ,4 B3 ,···,4 Bm via the above 4 A1 ,4 A2 ,4 A3 ,···,4 Am and the light is input to the condenser lens 4 A1 ,4 A2 ,4 A3 ,···,4 Am and the light is collected by the projection optical system 33 and emitted from the optical fiber B 441 ,FB 442 ,FB 443 ,···,FB 44m through the optical couplers OC1, OC2, OC3, . . . , OC m The above optical couplers OC1, OC2, OC3, OC m From the above optical fiber FB431 ,FB 432 ,FB 433 ,···,FB 43m The measurement light L is input to the optical multiplexing element 31B of the optical multiplexing / demultiplexing optical system 31 via the optical multiplexing element 31B, and is multiplexed by the optical multiplexing element 31B to form the measurement light L consisting of reflected light of each frequency component reflected at each measurement point on the measurement surface 5. S 'It is said that.

[0066] The measurement light L combined by the optical combining element 31B S ' denotes a signal from the optical multiplexing element 31B to the optical fiber FB 32 The optical coupler OC of the interference optical system 2A is C is entered into

[0067] In this optical multipoint measuring device 10A, an optical fiber using a PMF is used as the optical path, and the measuring light L S In the optical demultiplexing element 3A, the measurement light L S The frequency components of the linearly polarized optical comb obtained by splitting the multiple frequency components of the optical comb included in A1 ,4 A2 ,4 A3 ,···,4 Am The light is collected by the quarter-wave plate 4 B1 ,4 B2 ,4 B3 ,···,4 Bm The circularly polarized light beams are then irradiated onto the measurement surface 5 as the respective frequency components through the quarter wave plate 4. The reflected light beams of the circularly polarized light beams reflected by the measurement surface 5 are then irradiated onto the measurement surface 5 as the respective frequency components through the quarter wave plate 4. B1 ,4 B2 ,4 B3 ,···,4 Bm Each frequency component of linearly polarized light is collected through the condenser lens 4. A1 ,4 A2 ,4 A3 ,···,4 Am will be returned to

[0068] That is, in this optical multipoint measurement device 10A, the condenser lens 4 A1 ,4 A2 ,4 A3,···,4 Am Through the quarter wave plate 4 B1 ,4 B2 ,4 B3 ,···,4 Bm Measurement light L output from S Each frequency component of the optical comb is circularly polarized and irradiated onto the target. The reflected light from the target is then reflected by the quarter-wave plate 4. B1 ,4 B2 ,4 B3 ,···,4 Bm Through a condenser lens 4 A1 ,4 A2 ,4 A3 ,···,4 Am Each frequency component of the optical comb of the reflected light input to the condenser lens 4 is linearly polarized. A1 ,4 A2 ,4 A3 ,···,4 Am For the output light of 4 A1 ,4 A2 ,4 A3 ,···,4 Am The frequency components of the optical comb of the reflected light input to the optical comb have orthogonal polarization planes.

[0069] In this way, the optical couplers OC1, OC2, OC3, . . . , OC m is the measurement light L of linearly polarized light whose polarization planes are orthogonal to each other. S The frequency components of the reflected light reflected by the measurement surface 5 and the frequency components of the reflected light returning from the measurement surface 5 are input from opposite directions and output in opposite directions, functioning as a directional coupler.

[0070] The measurement light L is reflected at a plurality of m measurement points on the measurement surface 5 of the measurement object and returns via the projection optical system 33. S The reflected light of each frequency component is multiplexed by the optical multiplexing element 3B, and measurement light L consisting of the reflected light of each frequency component reflected at a plurality of measurement points on the measurement surface 5 is generated. S ' is the optical fiber FB from the optical multiplexing element 3B. 32 via the optical coupler OC of the interference optical system 2. C is entered into

[0071] 7A and 7B are diagrams illustrating the functions of the optical demultiplexing element 3A and the optical multiplexing element 3B of the optical demultiplexing / multiplexing optical system 31 provided in the optical demultiplexing / multiplexing head 34A in the optical multipoint measuring device 10A. As shown in FIG. 7A, the optical demultiplexing element 3A is a light source for measuring the measurement light L S Each frequency component of the optical comb contained in S(1) ,l S(2) ,l S(3) ,···,l S(m) 7B, the optical multiplexing element 3B has a function of splitting the measurement light beams l into a plurality of m beams of measurement light beams l reflected and returned from each measurement point on the measurement surface 5. S(1) ',l S(2) ',l S(3) ',···,l S(m) ' are combined to form the measurement light L S It has the function of '.

[0072] That is, in the optical multiplexing / demultiplexing head 34A in the optical multipoint measuring device 10A, as shown in FIG. 7A, the measurement light L S The optical demultiplexer 3A separates the frequency components of the optical comb contained in the plurality of m measurement beams l for each of the plurality of p frequency components of the optical comb. S(1) ,l S(2) ,l S(3) ,···,l S(m) and the beam splits into two beams, which are then fed to the projection optical head 4 of the projection optical system 33. (1) ,4 (2) ,4 (3) ,···,4 (m) The light is irradiated onto a plurality of m measurement points on the measurement surface 5 of the measurement object through the projection optical head 4 of the projection optical system 33 and is reflected by the measurement surface 5. (1) ,4 (2) ,4 (3) ,···,4 (m) The measurement light returning through l S(1) ',l S(2) ',l S(3) ',···,l S(m) The measurement light L' is multiplexed by the optical multiplexing element 3B. S 'The optical coupler OC of the above interference optical system 2A C Enter.

[0073] The interference optical system 2A receives the measurement light L output from the light source 1. S and reference beam L R are input, and the measurement light L input from the light source 1 is S is input to the optical multiplexing / demultiplexing head 34A, and the measurement light l is reflected at a plurality of measurement points on the measurement surface 5 and returns via the optical multiplexing / demultiplexing head 34A. S(1) ',l S(2) ',l S(3) ',···,l S(m) Measurement light L S ' and the reference light L input from the light source 1. R The interference light for measurement is then output to the optical coupler OC C and the measurement light L input from the light source 1. S and reference beam L R The interference light from the optical coupler OC D Output from

[0074] The interference light detector 6 to which the measurement interference light and the reference interference light obtained by the interference optical system 2A are input is connected to the optical coupler OC C Two optical fiber FBs externally connected to 26A1 ,FB 26A2 Through the above optical coupler OC C The measurement interference light detector 6A receives the measurement interference light input from the S and the optical coupler OC D Two optical fiber FBs externally connected to 26B1 ,FB 26B2 Through the above optical coupler OC D The reference interference light detector 6B receives the reference interference light input from the reference interference light detector 6B, detects the reference interference light, and converts it into an electrical signal to generate a reference interference signal S R Output.

[0075] Then, in the signal processing unit 7, the measurement interference signal S obtained in the interference light detection unit 6 is S and the reference interference signal S R, and performs multi-point distance measurement processing up to a plurality of measurement points on the measurement surface 5. That is, the signal processing unit 7 calculates the phase of the measurement interference signal S obtained by the interference light detection unit 6. S By FFT analysis, the measurement light l S(1) ',l S(2) ',l S(3) ',···,l S(m) For each of the multiple p frequency components of the optical comb included in ', the reference signal L R By finding the phase difference for each frequency component with respect to the above, the distances to the measurement points at multiple meters on the measurement surface 5 are calculated.

[0076] In this way, in this optical multipoint measurement device 10A, the measurement light L S The measurement light L output from the interference optical system 2A provided with the optical demultiplexing element 3A that demultiplexes the plurality of frequency components of the optical comb included in S and the measurement light L, which is provided with the optical multiplexing element 3B that multiplexes the reflected light of each frequency component reflected at a plurality of measurement points on the measurement surface 5 of the object. S Since the optical path for inputting the measurement light L′ to the interference optical system 2A is separated, the measurement light L S Even if a part of the reflected light is reflected by the optical demultiplexer 3A and an unnecessary reflected component is generated, this reflected component is transmitted to the optical fiber FB 23 The optical coupler OC of the interference optical system 2A is A Returning to this branch optical coupler OC A From optical fiber FB 12A 1A of the light source 1 via the optical coupler OC1 of the interference optical system 2A, and is absorbed by the isolator built into the light source unit. C The reference light L output from R and the above measurement light L S ' interference light, that is, the measurement interference light, and the optical coupler OC D The reference light L output from R and the above measurement light L S The interference light for reference, i.e., the interference light for reference, is not affected.

[0077] Therefore, in this optical multipoint measurement device 10A, the measurement light L irradiating the measurement surface 5 via the interference optical system 2A is S an optical demultiplexing element 3A provided in the optical path through which the optical couplers OC1, OC2, OC3, . . . , OC m This eliminates measurement errors caused by unwanted reflection components from various optical elements such as those mentioned above being mixed into the interference light required for multipoint distance measurement, thereby enabling highly accurate multipoint distance measurement.

[0078] Here, the optical couplers OC1, OC2, OC3, . . . , OC constituting the coupling optical system 32 provided in the optical multiplexing / demultiplexing head 34A in the optical multipoint measuring device 10A are m is the measurement light L of linearly polarized light whose polarization planes are orthogonal to each other. S and the frequency components of the light reflected by the measurement surface 5 and returning are input from opposite directions to each other, and function as a directional coupler that outputs in opposite directions to each other, and may be a PBC module or a circulator. The coupling optical system 32 includes the optical couplers OC1, OC2, OC3, . . . , OC m Instead of the above, for example, a fused PBC module that combines two orthogonal polarized beams and outputs them to one fiber, a fused PBC module that splits input light into orthogonal linearly polarized beams and outputs them to two PMFs, or a PBC module using birefringent crystals can be used.

[0079] Furthermore, as in the optical multipoint measurement device 100 shown in FIG. 8, the coupling optical system 32 provided in the optical multiplexing / demultiplexing head 34A can be built into the projection optical system 33.

[0080] FIG. 8 is a schematic diagram showing an example of the configuration of an optical multipoint measurement device 100 equipped with a projection optical head 134 incorporating a coupling optical element to which the present invention is applied.

[0081] The projection optical head 134 with built-in coupling optical element in this optical multipoint measurement device 100 includes a spectroscopic optical system 31 and a coupling optical element 4. C1 ,4C2 ,4 C3 ,···,4 Cm 4 m projection optical heads with built-in (1) ',4 (2) ',4 (3) ',···,4 (m) The projection optical system 133 includes a coupling optical element and a projection optical system 133 having a coupling optical element.

[0082] This optical multipoint measurement device 100 includes a coupling optical element 4 that functions as each PBC module of the coupling optical system 32 provided in the optical multiplexing / demultiplexing head 34A in the multipoint measurement device 10A. C1 ,4 C2 ,4 C3 ,···,4 Cm Projection optical head 4 (1) ',4 (2) ',4 (3) ',···,4 (m) ', and in this optical multipoint measurement device 100, the same components as those in the optical multipoint measurement device 10A are given the same reference numerals, and detailed description thereof will be omitted.

[0083] The projection optical head 4 of the projection optical head 134 with built-in coupling optical element in the optical multipoint measuring device 100 (1) ',4 (2) ',4 (3) ',···,4 (m) ' includes, for example, a projection optical element 4 having a configuration as shown in (A) and (B) of FIG. (0)A ' are used respectively.

[0084] 9A and 9B show the projection optical head 4 (1) ',4 (2) ',4 (3) ',···,4 (m) 1A and 1B are diagrams showing an example of the configuration of a projection optical element 44A used in the projection optical element 44A; FIG. 1A is a schematic diagram showing the configuration of the projection optical element 44A; and FIG. (0)A 10 is a front view of the two-core capillary 4C1 provided in the '.

[0085] This projection optics 4 (0)A' is a coupling optical unit 4C consisting of a two-core capillary 4C1 and a coupling optical element 4C2 having optical properties that align the axes of light beams whose polarization directions are orthogonal to each other and output from the tips of two optical fibers inserted into the two-core capillary 4C1. A The optical fiber FB 34 and output optical fiber FB 43 is externally derived.

[0086] The above coupling optical unit 4C A The directions of the stress-applying portions of the polarization-maintaining fibers inserted into the two-core capillary 4C1 provided in the optical fiber 4C1 are arranged to be orthogonal to each other, as shown in FIG. 9(B).

[0087] The input optical fiber FB led out from the two-core capillary 4C1 to the outside 34 is connected to the optical demultiplexing element 3A of the optical demultiplexing / multiplexing optical system 31, and is connected to the output side optical fiber FB led out from the two-core capillary 4C1 to the outside. 43 is connected to the optical demultiplexing element 3A of the optical demultiplexing / multiplexing optical system 31.

[0088] And this projection optical element 4 (0)A ', the optical fiber FB 34 The measurement light L is input through S The frequency components l are separated into multiple p frequency components. S is input to the condenser lens 4A via the coupling optical element 4C2. The frequency component l S is irradiated onto the measurement surface 5 of the measurement object through the quarter-wave plate 4B. The light reflected by the measurement surface 5 is converted into the frequency component l through the quarter-wave plate 4B. S is the frequency component l of the polarization plane that is perpendicular to the polarization direction. S ' and is returned to the condenser lens 4A.

[0089] The above frequency component l S is the frequency component l of the polarization plane that is perpendicular to the polarization direction. S' is condensed by the condenser lens 4A and is transmitted to the coupling optical section 4C. A The output optical fiber FB 43 and the output side of this optical fiber FB 43 The light is input to the optical multiplexing element 3B of the optical multiplexing / demultiplexing optical system 31 via the optical multiplexing element 3B.

[0090] The coupling optical element 4C2 may be made of a birefringent crystal for separating light beams by using walk-off, for example.

[0091] Furthermore, the projection optical head 4 of the projection optical head 134 with the built-in coupling optical element (1) ',4 (2) ',4 (3) ',···,4 (m) In the second embodiment, instead of the output coupling optical element 4C2 using the birefringent crystal, a Wollaston prism 4C as shown in (A) and (B) of FIG. b The projection optical element 4 using the coupling optical element 4C2' configured by the above (0)B ' can also be adopted.

[0092] In the Wollaston prism type projection optical system 133 provided in the projection optical head 134 with a built-in coupling optical element, a directional coupling loss from Port 1 to Port 2 of 80 dB to 90 dB was obtained as a result of actual measurements.

[0093] 10A and 10B show the projection optical element 4 used in the projection optical head 134 with built-in coupling optical element. (0)B 1A is a schematic diagram showing the configuration of a projection optical element 44B, and FIG. 1B is a diagram showing an example of the configuration of the projection optical element 44B. (0)B 10 is a front view of the two-core capillary 4C1 provided in the '.

[0094] This projection optics 4 (0)B ' is a coupling optical unit 4C consisting of a two-core capillary 4C1 and a coupling optical element 4C2' having optical characteristics that align the axes of light beams whose polarization directions are orthogonal to each other and output from the tips of two optical fibers inserted into the two-core capillary 4C1.B The optical fiber FB 34 and the output optical fiber FB 43 is externally derived.

[0095] The above coupling optical unit 4C B The directions of the stress-applying portions of the polarization-maintaining fibers inserted into the two-core capillary 4C1 provided in the optical fiber 4C1 are arranged to be orthogonal to each other as shown in FIG. 10(B).

[0096] The coupling optical element 4C2' includes two collimator lenses 4C a ,4C c Between Wollaston prism 4C b It is made by arranging the following.

[0097] This projection optics 4 (0)B ', the optical demultiplexer 131A is connected to the input optical fiber FB 34 The measurement light L is input through S The frequency component l of the optical comb S is input to the condenser lens 4A via the coupling optical element 4C2′, and the frequency component l S is irradiated onto the measurement surface 5 of the measurement object through the quarter-wave plate 4B. The reflected light from the measurement surface 5 is then irradiated onto the measurement surface 5 through the quarter-wave plate 4B. S is the frequency component l of the polarization plane that is perpendicular to the polarization direction. S ' and is returned to the condenser lens 4A.

[0098] The above frequency component l S is the frequency component l of the polarization plane that is perpendicular to the polarization direction. S The light is collected by the collecting lens 4A and is output to the output side optical fiber FB via the coupling optical element 4C2'. 43 and the output side of this optical fiber FB 43 The light is input to the optical multiplexing element 3B of the optical multiplexing / demultiplexing optical system 31 via the optical multiplexing element 3B.

[0099] The projection optical element 4 (0)A ',4(0)B In the case of the coupling optical elements 4C2 and 4C2', as shown in FIG. 9B and FIG. 10B, the stress applying portions are arranged orthogonal to each other, and the light beams having orthogonal polarizations are input from Port 1 and Port 2 of the double-core capillary 4C1 to the coupling optical elements 4C2 and 4C2'. The light beams have parallel optical axes and are output in the same direction as the coupling optical elements 4C2 and 4C2'. S The frequency component l of the optical comb S Port1 (input side optical fiber FB 34 The frequency component l is input from the direction of the stress applying part and reflected by the measurement surface 5. S ' to Port2 (output optical fiber FB 43 The light can be received in the direction of the stress applying part.

[0100] That is, in the projection optical head 134 with built-in coupling optical element in the optical multipoint measurement device 100, the optical coupler OC A From optical fiber FB 32 The measurement light L is input through S The optical demultiplexing element 3A of the optical multiplexing and demultiplexing optical system 31 separates the plurality of m measurement light beams L for each of the plurality of p frequency components of the optical comb. S(1) ,L S(2) ,L S(3) ,···,L S(m) Split into FB 341 ,FB 342 ,FB 343 ,···,FB 34m The projection optical head 4 of the projection optical system 133 is (1) ',4 (2) ',4 (3) ',···,4 (m) ' and input the above projection optical head 4 (1) ',4 (2) ',4 (3) ',···,4 (m) ' to a plurality of m measurement points on the measurement surface 5 of the measurement object, and is reflected by the measurement surface 5 and projected onto the projection optical head 4 of the projection optical system 33. (1) ',4 (2) ',4 (3) ',···,4 (m)'From Fiber Optic FB 431 ,FB 432 ,FB 433 ,···,FB 43m ,···FB 43mn The measurement light returning through l S(1) ',l S(2) ',l S(3) ',···,l S(m) The measurement light L′ is multiplexed by the optical multiplexing element 3B. S 'But optical fiber FB 32 The optical coupler OC of the interference optical system 2A is C is entered into

[0101] The interference optical system 2A receives the measurement light L output from the light source 1. S and reference beam L R The measurement light LS input from the light source 1 is input to the projection optical head 134 with a built-in coupling optical element, and the measurement light LS is reflected at a plurality of measurement points on the measurement surface 5 and returned via the projection optical head 134 with a built-in coupling optical element. S(1) ',l S(2) ',l S(3) ',···,l S(m) Measurement light L S ' and the reference light L input from the light source 1. R The interference light for measurement is then output to the optical coupler OC C and the measurement light L input from the light source 1. S and reference beam L R The interference light from the optical coupler OC D Output from

[0102] The interference light detector 6 to which the measurement interference light and the reference interference light obtained by the interference optical system 2A are input is connected to the optical coupler OC C Two optical fiber FBs externally connected to 26A1 ,FB 26A2 Through the above optical coupler OC C The measurement interference light detector 6A receives the measurement interference light input from theS and the optical coupler C of the interference optical system 2A D Two optical fiber FBs externally connected to 26B1 ,FB 26B2 Through the above optical coupler OC D The reference interference light detector 6B receives the reference interference light input from the reference interference light detector 6B, detects the reference interference light, and converts it into an electrical signal to generate a reference interference signal S R Output.

[0103] Then, in the signal processing unit 7, the measurement interference signal S obtained in the interference light detection unit 6 is S and the reference interference signal S R , and performs multi-point distance measurement processing up to a plurality of measurement points on the measurement surface 5. That is, the signal processing unit 7 calculates the phase of the measurement interference signal S obtained by the interference light detection unit 6. S By FFT analysis, the measurement light l S(1) ',l S(2) ',l S(3) ',···,l S(m) For each of the multiple p frequency components of the optical comb included in ', the reference signal L R By finding the phase difference for each frequency component with respect to the above, the distances to the measurement points at multiple meters on the measurement surface 5 are calculated.

[0104] In this optical multipoint measurement device 100, the measurement light L S The measurement light L output from the interference optical system 2A provided with the optical demultiplexing element 3A for demultiplexing the plurality of p frequency components of the optical comb included in S and the measurement light L is provided with the optical multiplexing element 3B that multiplexes the reflected light of each frequency component of the optical comb reflected at the multiple m measurement points on the measurement surface 5 of the object. S Since the optical path for inputting the measurement light L′ to the interference optical system 120 is separated, the measurement light L irradiating the measurement surface 5 through the interference optical system 2A is SThis eliminates measurement errors caused by unwanted reflection components from the optical demultiplexer 3A provided in the optical path through which the light passes, which are mixed into the interference light required for multi-point measurement, thereby enabling highly accurate multi-point distance measurement.

[0105] Here, in the projection optical head 34A with built-in coupling optical element in the optical multipoint measurement device 10A described above, the optical multiplexing / demultiplexing optical system 131 is connected to the projection optical system 133 via the coupling optical system 132, but in the optical multipoint measurement device 100, the coupling optical system 32 and the projection optical system 33 in the optical multipoint measurement device 10A are replaced with a projection optical system 133 with built-in coupling optical element that has the function of the coupling optical system 32, so that the fiber B connecting the coupling optical system 32 and the projection optical system 33 441 ,FB 442 ,FB 443 ,···,FB 44m ,···FB 44m Therefore, the projection optical head 134 with built-in coupling optical element can be configured with two optical systems, the optical multiplexing / demultiplexing optical system 31 and the projection optical system 133 with built-in coupling optical element. This not only simplifies the configuration but also reduces the need for the above-mentioned fiber B. 441 ,FB 442 ,FB 443 ,···,FB 44m ,···FB 44m No unnecessary reflection of light occurs at each end face of the

[0106] That is, using an element such as a PBC module as the coupling optical system 32, as in the projection optical head 34A with built-in coupling optical element in the optical multipoint measurement device 10A, complicates the optical system, and causes problems such as reflections inside the PBC module and the extinction ratio of the PM fiber. Furthermore, using a PBC module or the like increases the number of components. Reflections from the multiple lenses and fiber end faces inside the PBC module can also be problematic. However, in the optical multipoint measurement device 100, by providing the projection optical system 133 with built-in coupling optical element in the projection optical head 134 with built-in coupling optical element, it is not necessary to use a separate PBC module or the like. This allows for a configuration with a larger directional coupling loss from Port 1 to Port 2, thereby resolving these problems.

[0107] Next, Figures 11(A) and (B) are diagrams showing an example of the configuration of a coupling optical element array 44 provided in a projection optical head with a built-in coupling optical element in an optical multi-point measurement device according to the present invention, where (A) is a vertical cross-sectional side view of the coupling optical element array 44 and (B) is a vertical cross-sectional front view of the coupling optical element array 44.

[0108] FIG. 12 is a schematic diagram showing the configuration of an optical multipoint measurement device 100A that uses a projection optical head 134A with a built-in coupling optical element that includes the above-mentioned coupling optical element array 44.

[0109] In this optical multipoint measuring device 100A, as shown in FIGS. 11A and 11B, a plurality of (m×n) double-core capillaries are arranged in an array, and a birefringent crystal 4C having a size that covers the entire array is attached to the coupling optical element 44. A1 ,44 A2 ,44 A3 ,···,44 Am ,···,44 Amn A modularized coupling optical element array 44 is employed in the projection optical system 133A.

[0110] Here, this optical multi-point measurement device 100A is obtained by replacing the projection optical head 134 with a projection optical head 134A with a built-in coupling optical element in the optical multi-point measurement device 100 shown in Figure 8, and in this optical multi-point measurement device 100A, the same components as those in the optical multi-point measurement device 1 described above are given the same symbols, and detailed explanations of them will be omitted.

[0111] This optical multipoint measurement device 100A uses coherent measurement light L, which has a spectrum with a predetermined frequency interval and is phase-synchronized with each other. S and reference beam L R and a light source 1 that outputs measurement light L S and reference beam L R are the optical fibers FB 12A ,FB 12B and the measurement light LS a projection optical head 134A incorporating a coupling optical element to which the measurement interference light and the reference interference light outputted via the interference optical system 2A are inputted, an interference light detection unit 6 to which the measurement interference light and the reference interference light outputted via the interference optical system 2A are inputted, and a measurement interference signal S obtained by the interference light detection unit 6. S and the reference interference signal S R The signal processor 7 receives the signal.

[0112] The projection optical head 134A with built-in coupling optical element in this optical multipoint measurement device 100A is provided with an optical fiber FB 23 The optical demultiplexing element 3A and the interference optical system 2A are connected via an optical fiber FB 32 and a light multiplexing / demultiplexing optical system 31 including a light multiplexing element 3B connected via a plurality of (m×n) coupling optical elements 44 of the projection optical system 33 in the optical multipoint measurement device 100. A1 ,44 A2 ,44 A3 ,···,44 Am ,···,44 Amn a coupling optical element array 44 in which the above-mentioned lenses are arranged two-dimensionally and modularized, and a condenser lens 4 of the projection optical system 33. A1 ,4 A2 ,4 A3 ,···,4 Am ,···,4 Amn That is, the light-collecting optical element 4A functions as a projection optical element. a ,4A b A set of optical systems 4A consisting of ab and the quarter-wave plate 4 of the projection optical system 33. B1 ,4 B2 ,4 B3 ,···,4 Bm ,···,4 Bmn The projection optical system 133A is made up of one quarter-wave plate 4B that functions as a projection optical system.

[0113] Here, the optical system 4A shown in FIG. abis a simplified representation of a double-telecentric optical system. In reality, it is made up of many lenses. A double-telecentric optical system can project and focus the measurement light output vertically from the coupling optical element array 44 vertically onto a horizontal target. This is the most sensitive projection optical system when the target is flat. For large targets, it is possible to use a telecentric optical system on only one side and an fθ optical system on the other side. It is also not necessary to use a telecentric optical system; select an optical system that suits the size and shape of the target.

[0114] The optical demultiplexing element 3A provided in the optical demultiplexing / multiplexing optical system 31 in the projection optical head 134A with built-in coupling optical element is configured to split the measurement light L S Each frequency component of the optical comb contained in S(1) ,l S(2) ,l S(3) ,···,l S(m) 7B, the optical multiplexing element 3B has a function of splitting the measurement light beams l into a plurality of m beams each split into a plurality of p frequency components. S(1) ,l S(2) ,l S(3) ,···,l S(m) The measurement light L S It has the function of '.

[0115] In addition, the plurality of (m×n) coupling optical elements 44 in the coupling optical element array 44 A1 ,44 A2 ,44 A3 ,···,44 Am ,···,44 Amn For example, the projection optical element 4 shown in (A) and (B) of FIG. (0)A 'Combined Optical Section 4C A are used respectively.

[0116] This coupling optical unit 4C AThe optical coupling element 4C2 has optical properties that allow the axes of the light beams whose polarization directions are orthogonal to each other and output from the tips of the two optical fibers inserted into the two-core capillary 4C1 to coincide with each other. 34 and output optical fiber FB 43 is externally derived.

[0117] In this coupling optical element array 44, the input side FB 341 ,FB 342 ,FB 343 ,···,FB 34m and output optical fiber B 4311 ,FB 432 ,FB 433 ,···,FB 43m ,···FB 43mn Although it has been assumed that each of the optical fibers is led out to the outside from the two-core capillary 4C1, it is also possible to adopt a structure in which the direction of the PMF can be controlled by precisely arranging multiple optical fibers, such as a structure in which multiple optical fibers are led out to the outside through multiple insertion holes provided in a substrate, without using a two-core capillary.

[0118] Furthermore, in the projection optical head 134A with built-in coupling optical elements, a plurality of (m×n) coupling optical elements 44 are arranged so that each frequency component of the optical comb of the measurement light is irradiated onto m×n measurement points arranged two-dimensionally in a matrix. A1 ,44 A2 ,44 A3 ,···,44 Am ,···,44 Amn However, depending on the object to be measured, a plurality of coupling optical elements 44 may be used. A1 ,44 A2 ,44 A3 ,···,44 Am ,···,44 Amn Alternatively, a modularized coupling optical element array may be employed in which the optical elements are arranged two-dimensionally in a fine lattice pattern (for example, a hexagonal fine lattice pattern).

[0119] The plurality of modularized (m×n) coupling optical elements 44 A1 ,44 A2 ,44 A3 ,···,44 Am ,···,44 Amn is a set of multiple (m×n) optical fibers FB 341 ,FB 342 ,FB 343 ,···,FB 34m ,···,FB 34mn and a plurality of (m×n) optical fibers B 4311 ,FB 432 ,FB 433 ,···,FB 43m ,···FB 43mn 1. The optical multiplexing element 3B of the optical multiplexing / demultiplexing optical system 31 is connected to the optical multiplexing element 3B via the optical multiplexing / demultiplexing element 3B.

[0120] In the projection optical head 134A with built-in coupling optical element, the measurement light L S The frequency components of the optical comb are split into multiple (m × n) measurement light beams l S(1) ,l S(2) ,l S(3) ,···,l S(m) ,···,l S(mn) There are multiple (m×n) optical fibers FB 341 ,FB 342 ,FB 343 ,···,FB 34m ,···,FB 34mn The plurality of modularized (m×n) coupling optical elements 44 of the coupling optical element array 44 are connected via the A1 ,44 A2 ,44 A3 ,···,44 Am ,···,44 Amn and the coupling optical element 44 A1 ,44 A2 ,44 A3 ,···,44 Am ,···,44 Amn A focusing optical element 4A functions as a projection optical element via a ,4A bA set of optical systems 4A consisting of ab is entered into

[0121] This set of optical systems 4A ab Measurement light l focused by S(1) ,l S(2) ,l S(3) ,···,l S(m) ,···,l S(mn) is irradiated onto the measurement surface 5 of the measurement object through one 1 / 4 wavelength plate 4B. The reflected light reflected by the measurement surface 5 is reflected back to the measurement light 1 through the 1 / 4 wavelength plate 4B. S(1) ,l S(2) ,l S(3) ,···,l S(m) ,···,l S(mn) The measurement light l is polarized in a plane perpendicular to the polarization direction. S(1) ',l S(2) ',l S(3) ',···,l S(m) ',···,l S(mn) 'The above set of optical systems 4A ab will be returned to

[0122] The above measurement light S(1) ',l S(2) ',l S(3) ',···,l S(m) ',···,l S(mn) ' denotes the set of optical systems 4A ab and the light is collected by the coupling optical element 44 A1 ,44 A2 ,44 A3 ,···,44 Am ,···,44 Amn to the output side optical fiber B 4311 ,FB 432 ,FB 433 ,···,FB 43m ,···FB 43mn The light is input to the optical multiplexing element 3B of the optical multiplexing / demultiplexing optical system 31 via the optical multiplexing element 3B.

[0123] The coupling optical element 44 A1 ,44 A2 ,44 A3 ,···,44 Am ,···,44 AmnFor example, a birefringent crystal or a Wollaston prism may be used.

[0124] In addition, in this optical multipoint measuring device 100A, the coupling optical element 44 A1 ,44 A2 ,44 A3 ,···,44 Am ,···,44 Amn Secondly, by using a birefringent crystal of a size that covers the entire coupling optical element array, the number of parts can be reduced compared to when a Wollaston prism is used.

[0125] The optical multiplexing element 3B of the optical demultiplexing / multiplexing optical system 31 receives the measurement light L reflected at a plurality of measurement points on the measurement surface 5 of the measurement object and returns via the projection optical system 133A. S(1) ',L S(2) ',L S(3) ',···,L S(m) ',···,L S(mn) The measurement light L S 'Fiber Optic FB 32 The optical coupler OC of the interference optical system 2A is C is entered into

[0126] That is, in the optical multiplexing / demultiplexing head 130 in this optical multipoint measuring device 100A, the measurement light L S The optical demultiplexer 3A separates each frequency component of the optical comb contained in the plurality of (m×n) measurement beams l for each of the plurality of p frequency components of the optical comb. S(1) ',l S(2) ',l S(3) ',···,l S(m) ',···,l S(mn) ', and each frequency component is irradiated onto a plurality of measurement points on the measurement surface 5 of the measurement target via the projection optical system 133A. The measurement light l is reflected by the measurement surface 5 and returns via the projection optical system 133A. S(1) ',l S(2) ',l S(3) ',···,l S(m) ',···,l S(mn)' are multiplexed by the optical multiplexing element 3B of the optical multiplexing and demultiplexing optical system 31 to generate a plurality of (m×n) measurement beams l for each of the plurality of frequency components p. S(1) ',l S(2) ',l S(3) ',···,l S(m) ',···,l S(mn) 'Let's say.

[0127] The optical coupler OC of the interference optical system 2A C is a plurality of (m×n) measurement light beams l for each of a plurality of p frequency components of the optical comb reflected at a plurality of measurement points on the measurement surface 5. S(1) ',l S(2) ',l S(3) ',···,l S(m) ',···,l S(mn) The measurement light LS' consisting of 32 and the second optical comb generator (COMB2) 1B of the light source 1 is inputted via the optical fiber FB 12B via optical coupler OC B Reference light L input to R Optical fiber FB 2B1 The measurement light L is input through S ' and the reference beam L R The optical coupler OC of the interference optical system 2A outputs the interference light with the optical coupler OC of the interference optical system 2A as interference light for measurement. D is a signal from the first optical comb generator (COMB1) 1A of the light source 1 to the optical fiber FB 12A via optical coupler OC A The measurement light LS input to the optical fiber FB 2A2 and the second optical comb generator (COMB2) 1B of the light source 1 is inputted via the optical fiber FB 12 via optical coupler OC B The reference light LR input to the optical fiber FB 2B2 The measurement light L is input through S and reference beam L R The interference light with the reference light is output as reference interference light.

[0128] The interference light detector 6 receives the interference light for measurement and the interference light for reference obtained by the interference optical system 2A, and the interference light detector 6 receives the interference light for measurement and the interference light for reference obtained by the interference optical system 2A. CTwo optical fiber FBs externally connected to 26A1 ,FB 26A2 The measurement interference light detector 6A receives the measurement interference light via the S and the optical coupler OC D Two optical fiber FBs externally connected to 26B1 ,FB 26B2 The reference interference light is detected by an interference light detector 6B that receives the reference interference light via the R Output.

[0129] The signal processing unit 7 then processes the measurement interference signal S obtained by the interference light detection unit 6. S and the reference interference signal S R , and performs multi-point distance measurement processing up to a plurality of (m×n) measurement points on the measurement surface 5. That is, the signal processing unit 7 calculates the phase of the measurement interference signal S obtained by the interference light detection unit 6. S By FFT analysis, the above multiple (m×n) measurement light beams l S(1) ',l S(2) ',l S(3) ',···,l S(m) ',···,l S(mn) For each of the multiple p frequency components of the optical comb included in ', the reference signal L R By finding the phase difference for each frequency component with respect to the above, the distances to the plurality of (m×n) measurement points on the measurement surface 5 are calculated.

[0130] In this optical multipoint measurement device 100A, similar to the projection optical system 133 in the optical multipoint measurement device 100, a projection optical system 133A with a built-in coupling optical element that has the function of the coupling optical system 32 in the optical multipoint measurement device 10A is provided, and by employing a coupling optical element array 44 in the projection optical system 133A with a built-in coupling optical element, it is possible to transmit light from the optical branching element 3A of the optical branching / combining optical system 31 to a plurality of optical fibers FB 341 ,FB 342 ,FB 343 ,···,FB 34m,···,FB 34mn The above measurement L is input via S Multiple (m × n) measurement light l for each frequency component p of the optical comb S(1) ,l S(2) ,l S(3) ,···,l S(m) ,···,l S(mn) The above-mentioned focusing optical element 4A a ,4A b A set of optical systems 4A consisting of ab The light is focused by the quarter-wave plate 4B and irradiated onto a plurality of (m×n) measurement points on the measurement surface 5 of the object to be measured. The reflected light reflected at the plurality of (m×n) measurement points on the measurement surface 5 is irradiated via the quarter-wave plate 4B into a plurality of (m×n) measurement light beams l for each of a plurality of p frequency components of an optical comb having a polarization plane perpendicular to the polarization direction of the irradiated frequency component. S(1) ',l S(2) ',l S(3) ',···,l S(m) ',···,l S(mn) ', the above set of optical systems 44A ab and the light is collected by the coupling optical element array 44 and output to a plurality of optical fibers B 4311 ,FB 432 ,FB 433 ,···,FB 43m ,···FB 43mn The light can be input to the optical multiplexing element 3B of the optical multiplexing / demultiplexing optical system 31 via the optical multiplexing / demultiplexing optical system 31, thereby solving the various problems with the projection optical head 34A of the optical multipoint measurement device 10A, eliminating the need to use a separate PBC module or the like, and by configuring the coupling optical system to have a large directional coupling loss from the optical path on the input side to the optical path on the output side, measurement errors caused by unnecessary reflected components mixing into the measurement light required for multipoint measurement can be eliminated, making it possible to perform multipoint simultaneous measurement with high precision.

[0131] Here, in the interference optical system 2, 2A in the optical multipoint measurement device 10, 10A, 100, 100A, the measurement light L output from the light source 1 S and reference beam L R The interference light of the light source 1 is output as a reference interference light, and the measurement light L Sis irradiated onto a measurement surface 5 of the measurement target from the interference optical system 2, 2A via the optical multiplexing / demultiplexing head 34 and the projection optical head 34A, 134, 134A with a built-in coupling optical element, and interference light of the measurement light LS' and the reference light LR that is reflected by the measurement surface 5 and returned via the optical multiplexing / demultiplexing head 34 and the projection optical head 34A, 134, 134A with a built-in coupling optical element is output as measurement interference light, and an interference light detection unit 6 including a measurement interference light detector 6A that receives the measurement interference light output from the interference optical system 2, 2A and an interference light detector 6B that receives the reference interference light output from the interference optical system 2, 2A detects the measurement interference light by the measurement interference light detector 6A and converts it into an electrical signal to obtain a measurement interference signal SS, and the reference interference light is detected by the interference light detector 6B and converted into an electrical signal to obtain a reference interference signal SR, and a signal processing unit 7 outputs the measurement interference signal S obtained by the interference light detection unit 6 S and the reference interference signal S R The phase of each frequency is calculated by FFT analysis, and multi-point distance measurement processing is performed up to a plurality of measurement points on the measurement surface 5 at a distance of several meters.

[0132] In the optical multipoint measuring devices 10, 10A, 100, and 100A, the signal processing unit 7 converts the measurement interference signal S obtained by the interference light detection unit 6 into S By FFT analysis, the measurement light l S(1) ',l S(2) ',l S(3) ',···,l S(m) ',···,l S(mn) For each of the plurality of frequency components p included in the signal ', the phase difference of each frequency component relative to the reference signal is calculated to calculate the distances to the measurement points of the plurality of m on the measurement surface 5. S is the measurement light L reflected by the measurement surface 5 and returned. S ' and the reference beam L R Since the interference signal is obtained by detecting the interference light for measurement, which is the interference light of S By DFT analysis of only the above multiple m measurement light l S(1) ',l S(2) ',lS(3) ',···,l S(m) ',···,l S(mn) For each of the multiple p frequency components included in ', the phase difference of each frequency component with respect to the reference signal can be calculated.

[0133] That is, the optical multipoint measuring devices 10, 10A, 100, 100A include, for example, an optical multipoint measuring device 100B shown in FIG. 13, an interference optical system 2B that outputs only interference light for measurement, an interference light detecting unit 6′ that receives only interference light for measurement, and an interference signal S for measurement obtained by the interference light detecting unit 6′. S The signal processing unit 7' can be configured to obtain the phase difference of each of the plurality of frequency components p contained in the signal p relative to the reference signal by DFT analysis of only the signal p.

[0134] This optical multi-point measurement device 100B is a modified example of the optical multi-point measurement device 100A, and in this optical multi-point measurement device 100B, the same components as those in the optical multi-point measurement device 100A are given the same symbols in the figures, and detailed explanations of them will be omitted.

[0135] In this optical multipoint measuring device 100B, measurement light L output from a light source 1 S A plurality of (m×n) measurement beams l are output from the interference optical system 2B via the projection optical head 134A with built-in coupling optical element. S(1) ,l S(2) ,l S(3) ,···,l S(m) ,···,l S(mn) and irradiates a plurality of (m×n) measurement points on a measurement surface 5 of a measurement object, and the measurement light LS′ reflected by the measurement surface 5 and returned via the projection optical head 134A with the built-in coupling optical element and the reference light LR are obtained as measurement interference light by the interference optical system 2B. In an interference light detection unit 6′ having a measurement interference light detector 6A that receives the measurement interference light output from the interference optical system 2B, the measurement interference light is detected by the measurement interference light detector 6A and converted into an electrical signal to obtain a measurement interference signal SS. In a signal processing unit 7′, the measurement interference signal S obtained by the interference light detection unit 6′ is Sand the reference interference signal S R The phase of each frequency is calculated by FFT analysis, and multi-point distance measurement processing is performed up to a plurality of measurement points on the measurement surface 5 at a distance of several meters. [Explanation of symbols]

[0136] 1A First optical comb generator (COMB1), 1B Second optical comb generator (COMB2), 4 (1) ',4 (2) ',4 (3) ',···,4 (m) ',4 (1) ',4 (2) ',4 (3) ',···,4 (m) ' Projection optical head, 4 A1 ,4 A2 ,4 A3 ,···,4 Am ,···,4 Amn ,4A Condenser Lens, 4A a ,4A b Concentrating optics, 4A ab Complete optical system, 4 B1 ,4 B2 ,4 B3 ,···,4 Bm ,4B 1 / 4 wave plate, 4C birefringent crystal, 4C A ,4C B Coupling optics, 4C12-core capillary, 4C2,4C2',44 A1 ,44 A2 ,44 A3 ,···,44 Am ,···,44 Amn Coupling optics, 4C a ,4C c Collimator lens, 4C b Wollaston prism, 5 measurement surface, 6, 6' interference light detection unit, 6A interference light detector, 6B reference light detector, 7, 7' signal processing unit, 10, 110 light source, 20, 120, 120' interference optical system, 30, 130, 130 (1) ,130 (2) ,130 (3),130D optical multiplexing / demultiplexing head, 130A projection optical head unit, 31, 131 optical multiplexing / demultiplexing optical system, 31A, 131A optical multiplexing element, 31B, 131B optical multiplexing element, 32 coupling optical system, 33, 133 projection optical system, 40, 140, 140' interference light detection unit, 44 coupling optical element array, 4 (0)A ',4 (0)B ',44A,44B Projection optical element, 44D Fiber array, 50,150,150',150A,150B,150C,150D Signal processing unit, 60 RC helicopter, 61 Main rotor blade, 10,10A,100,100A,100B Optical multi-point measurement device, 120C Interference optical system group, 131' Input / output optical selection unit, 131D Optical multiplexer / demultiplexer element, 131A' 1-input multi-output optical switch, 131B' Multi-input 1-output optical switch, 34A,133,134,134A Projection optical head with built-in coupling optical element, 200 Experimental equipment, FB 12A ,FB 12B ,FB 2A1 ,FB 2A2 ,FB 2B1 ,FB 2B2 ,FB 23 ,FB 26A1 ,FB 26A2 ,FB 26B1 ,FB 26B2 ,FB 32 ,FB 341 ,FB 342 ,FB 343 ,···,FB 34m ,···,FB 34mn ,B 431 ,FB 432 ,FB 433 ,···,FB 43m ,···FB 43mn ,B 441 ,FB 442 ,FB 443 ,···,FB 44m ,···FB 44mn Optical fiber, FB 34 Input optical fiber, FB 43 Output optical fiber, OC A ,OC B ,OC C ,OC D ,OC E,OC1,OC2,OC3,···,OC m Optical coupler, L S ,LS',l S(1) ,l S(2) ,l S(3) ,···,l S(m) ,···,l S(mn) ,l S(1) ',l S(2) ',l S(3) ',···,l S(m) ',···,l S(mn) ' Measuring light, L R Reference light, S S Measurement interference signal, S S(1) ,S S(2) ,S S(3) Distance signal waveform, S R Reference interference signal

Claims

1. a light source that outputs coherent measurement light and reference light, the measurement light and reference light having a spectrum with a predetermined frequency interval; an optical multiplexing / demultiplexing head that separates the frequency components included in the measurement light output from the light source into a plurality of frequency components, irradiates the plurality of measurement points on a measurement surface of a measurement object to be measured as a plurality of measurement light beams for the plurality of frequency components, and multiplexes the plurality of measurement light beams for the plurality of frequency components that are reflected and returned from the measurement surface; an interference optical system that 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 multiplexing / demultiplexing head, and causes the reference light output from the light source to interfere with the multiple measurement light beams for the multiple frequency components that are reflected at multiple measurement points on the measurement surface and returned via the optical multiplexing / demultiplexing head, thereby outputting 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; and a signal processing unit for analyzing the measurement interference signal obtained by the measurement light detection unit.

2. 2. The optical multi-point measurement device according to claim 1, wherein the optical multiplexing and demultiplexing head comprises: an optical demultiplexing element that demultiplexes each frequency component contained in the measurement light input from the interference optical system into a plurality of frequency components; a projection optical system that irradiates a plurality of measurement points on a measurement surface of the object to be measured with the plurality of measurement light beams for each of the plurality of frequency components demultiplexed by the optical demultiplexing element; an optical multiplexing element that multiplexes the plurality of measurement light beams for each of the plurality of frequency components reflected and returned from the measurement surface and inputs them into the interference optical system; and a coupling optical system that inputs the measurement light beams demultiplexed by the optical demultiplexing element into 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.

3. The optical demultiplexing element demultiplexes each frequency component contained in the measurement light input from the interference optical system through one optical fiber into a plurality of frequency components, and outputs the plurality of measurement light beams for each of the plurality of frequency components through the plurality of optical fibers; the optical combining element combines the plurality of measurement light beams for each of the plurality of frequency components input through the plurality of optical fibers, and outputs the combined measurement light through one optical fiber; 3. The optical multi-point measurement device according to claim 2, wherein the combining optical system includes a combining optical element that aligns the optical axes of two light beams whose polarization directions are orthogonal to each other and output from two optical fibers.

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

5. 5. The optical multipoint measuring device according to claim 4, wherein the coupling optical element is made of a birefringent crystal.

6. 5. The optical multipoint measuring device according to claim 4, wherein the coupling optical element is a Wollaston prism.

7. 7. The optical multipoint measurement device according to claim 3, wherein 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 collected by a collecting optical element and output toward the measurement surface of the measurement object, and each frequency component of the measurement light reflected and returned by the measurement surface is collected by the collecting optical element and input to the coupling optical element array.

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