Spectrometry device and spectrometry method

Abstract

A spectrometry device (1) according to an embodiment of the present invention comprises: a first fiber unit (70) into which irradiation light enters; a portable unit (80) to which the first fiber unit is connected; a spectroscope (50) which diffracts a signal light; a second fiber unit (40) which is connected to the portable unit (80) and in which a plurality of second fibers are arranged adjacent to each other on an incident end surface, and a plurality of fibers are arranged in a multi-line shape so as to be spaced apart on an emission end surface; and a processing unit that generates a spectral image of a sample from a detection result of a two-dimensional array photodetector by referring to the arrangement relationship between the plurality of fibers on the incident end surface and the emission end surface of the second fiber unit (40).

Description

Spectroscopic measurement device and spectroscopic measurement method

[0001] The present invention relates to a spectroscopic measurement device and a spectroscopic measurement method, and more particularly to a spectroscopic measurement device and a spectroscopic measurement method for generating a spectroscopic image by spectroscopically measuring signal light such as Raman scattered light generated in a sample.

[0002] Patent Document 1 and Non-Patent Documents 1 to 4 disclose methods for measuring Raman spectra. Patent Document 1 discloses a multifocal confocal Raman microscope using a fiber bundle. Light from a pinhole array is incident on the input end of the fiber bundle. In Non-Patent Document 1, the fiber bundle is placed in front of the spectroscope. Also, in Non-Patent Document 1, the fibers are arranged in a row at the output end.

[0003] In Non-Patent Document 2, multi-focus is generated by modulating illumination light with a liquid crystal spatial light modulator. In Non-Patent Document 3, a multi-focus confocal Raman spectroscopic microscope is disclosed. In Non-Patent Document 3, multi-focus is generated using a microlens array. Furthermore, Non-Patent Document 3 uses a multi-fiber. In Non-Patent Document 4, 21 x 21 = 441 multi-focus points are simultaneously illuminated. Then, Raman scattered light from the multi-focus is guided to a spectroscope by a bundle fiber.

[0004] Japanese Patent Application Laid-Open No. 2012-237647

[0005] “High-resolution confocal Raman microscopy using pixel reassignment” Roider, et al., Optics Letters Vol. 41, Issue 16, pp. 3825-3828 (2016) “Tissue diagnosis using power-sharing multifocal Raman micro-spectroscopy and auto-fluorescence imaging” Sinjab, et al., Biomed. Opt. Express 7, 2993 (2016). “Rapid and accurate peripheral nerve imaging by multipoint Raman spectroscopy” Kumamoto, et al., Sci. Rep. 7, 845 (2017). Internet search: https: / / www.tokyoinst.co.jp / products / detail / raman_microscopy / TI02 / index.html [Searched June 16, 2023] Internet search: https: / / www.tem-inc.co.jp / products / detail-29.php [Searched December 8, 2021]

[0006] It is desirable to perform spectroscopic measurement of Raman scattered light for various samples and generate spectroscopic images. However, the Raman spectroscopic imaging methods described in Non-Patent Documents 1 to 4 use an optical microscope housing, which limits the size of the sample to be mounted on the optical microscope stage. Therefore, there is a problem in that a large stage is required to perform spectroscopic measurement on a large sample.

[0007] The present disclosure has been made in consideration of the above points, and has an object to provide a small spectroscopic measurement device and a spectroscopic measurement method that are capable of performing spectroscopic measurement on a variety of samples.

[0008] The spectroscopic measurement device according to this embodiment includes a light source that generates illumination light, a spatial light modulator that spatially modulates the illumination light from the light source, a first fiber unit to which the illumination light is incident, a portable unit to which the first fiber unit is connected, an illumination optical system that is housed in the portable unit and that guides the illumination light emitted from the first fiber unit to a sample, a detection optical system that is housed in the portable unit and that guides signal light from the sample that has been illuminated with the illumination light, a spectroscope that splits the signal light and detects it with a two-dimensional array photodetector, and a detection optical system that is connected to the portable unit. a second fiber unit having a plurality of fibers that guide the signal light from the second fiber unit to the spectrometer, wherein the plurality of fibers are arranged adjacent to each other at an incident end face of the second fiber unit and the plurality of fibers are arranged in a spaced-apart multi-line pattern at an exit end face of the second fiber unit on the spectrometer side; and a processing unit that generates a spectral image of the sample from the detection results of the two-dimensional array photodetector by referring to the arrangement relationship of the plurality of fibers at the incident end face and the exit end face of the second fiber unit.

[0009] The spectroscopic measurement device may further include a spatial light modulator that spatially modulates the illumination light from the light source, and the illumination light modulated by the spatial light modulator may be incident on the first fiber unit.

[0010] The spectroscopic measurement device may include a camera that captures an optical image of the sample, and a plurality of points on the sample extracted based on the optical image may be selectively illuminated.

[0011] The above-mentioned spectroscopic measurement device may further include an observation illumination light source that generates observation illumination light, wherein observation light from the sample illuminated with the observation illumination light propagates through the illumination optical system and enters the first fiber unit, and the camera detects the observation light emitted from the first fiber unit.

[0012] In the above spectroscopic measurement device, the observation illumination light source may be a ring illumination provided at a tip of the portable unit on the sample side.

[0013] In the above spectroscopic measurement device, a plurality of points on the sample extracted based on the optical image may be selectively illuminated.

[0014] In the above spectroscopic measurement device, the incident end face of the second fiber unit may be arranged at a position conjugate with the sample.

[0015] In the above spectrometric measurement device, a window that transmits the irradiation light and the signal light may be provided at a tip of the portable unit.

[0016] In the above spectroscopic measurement device, the number of fibers included in one line may decrease toward both ends of the output end face of the second fiber unit in a direction corresponding to the dispersion direction of the spectroscope.

[0017] The spectroscopic measurement device according to the embodiment includes a light source that generates illumination light, a spectrometer that disperses signal light from a sample illuminated with the illumination light and detects it with a two-dimensional array photodetector, a fiber unit having a plurality of fibers arranged in an optical path from the sample to the spectrometer, wherein the plurality of fibers are arranged adjacent to each other at the incident end face of the fiber unit and the plurality of fibers are arranged in a spaced-apart multi-line configuration at the exit end face, and a processing unit that generates a spectral image of the sample from the detection results of the two-dimensional array photodetector by referring to the arrangement of the plurality of fibers at the incident end face and the exit end face of the fiber unit, wherein the number of fibers included in one line decreases toward both ends of the exit end face in the direction corresponding to the dispersion direction of the spectrometer.

[0018] In the above spectroscopic measurement device, the signal light from multiple points on the sample may be detected by the spectrometer to measure multiple spectra, and principal component analysis may be performed on the multiple spectra to calculate scores of the principal components, and the scores of the principal component analysis may be used to identify the components contained in the sample.

[0019] In the above spectroscopic measurement device, the plurality of learning data may be obtained by detecting signal light from a plurality of points of a reference sample whose components are known using the spectrometer, and a discriminant equation for discriminating the components may be calculated by performing supervised learning using the learning data.

[0020] A spectroscopic measurement method according to an embodiment includes the steps of generating illumination light from a light source, spatially modulating the illumination light from the light source with a spatial light modulator, making the illumination light modulated by the spatial light modulator incident on a first fiber unit connected to a portable unit, guiding the illumination light emitted from the first fiber unit to a sample using an illumination optical system housed in the portable unit, making signal light from the sample incident on a detection optical system provided in the portable unit, and detecting a plurality of incident light beams on an incident end surface of a second fiber unit connected to the portable unit. The method includes the steps of: making the signal light that has propagated through the detection optical system incident on an incident end face where fibers are arranged adjacent to each other; making the signal light exit from an exit end face of the second fiber unit where the plurality of fibers are arranged in a spaced multi-line configuration; spectrally splitting the signal light that has exited from the exit end face and detecting it with a two-dimensional array photodetector; and generating a spectral image of the sample from the detection results of the two-dimensional array photodetector by referring to the arrangement relationship of the plurality of fibers at the incident end face and the exit end face of the second fiber unit.

[0021] According to the present invention, it is possible to provide a small spectroscopic measurement device and a spectroscopic measurement method that are capable of performing spectroscopic measurement on a variety of samples.

[0022] FIG. 1 is a schematic diagram showing a spectroscopic measurement device according to a first embodiment. FIG. 1 is a schematic diagram showing the configuration of an irradiation optical system and a detection optical system housed in a portable unit. FIG. 2 is a diagram showing the fiber arrangement at the incident end and the exit end of a fiber unit. FIG. 3 is a diagram showing an image of the light receiving surface of a photodetector. FIG. 4 is a diagram for explaining a process for identifying an analysis target from a measurement spectrum. FIG. 5 is a diagram for explaining an example of a spectroscopic measurement device. FIG. 6 is a schematic diagram showing the configuration of a spectroscopic measurement device according to a second embodiment. FIG. 7 is a schematic diagram for explaining a configuration when the number of fibers in each row is the same. FIG. 8 is a schematic diagram for explaining a configuration when the number of fibers in each row is different. FIG. 9 is a diagram showing the incident end and the exit end of a fiber unit and measurement results in a spectrometer. FIG. 10 is a diagram showing measurement results of PE (Polyethylene) and PDMS (Polydimethylsiloxane). FIG. 11 is a diagram showing a laser irradiation pattern and a Raman spectroscopic image. FIG. 12 is a diagram showing measurement results of PS (polystyrene) and PVC (polyvinyl chloride). FIG. 13 is a flowchart showing a method for discriminating the components of a sample. FIG. 14 is a graph showing the results of principal component analysis of Raman spectra. FIG. 15 is a graph showing principal component scores for the first to fifth principal components. 1 is a table for explaining the results of component discrimination for each measurement point; FIG. 2 is a diagram for explaining a method for discriminating a plurality of measurement points collectively and the results thereof; and FIG. 3 is a table for explaining the discrimination results when the discrimination threshold is changed when discriminating a plurality of measurement points collectively.

[0023] Below, embodiments to which the present invention can be applied are described. The following description is for describing embodiments of the present invention, and the present invention is not limited to the following embodiments. For clarity of explanation, the following description has been omitted and simplified as appropriate. Furthermore, a person skilled in the art would be able to easily modify, add, or convert each element of the following embodiments within the scope of the present invention. Note that elements with the same reference numerals in each drawing indicate similar elements, and descriptions thereof will be omitted as appropriate.

[0024] Embodiment 1 A spectroscopic measurement device and a measurement method according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing the overall configuration of the spectroscopic measurement device 1. The spectroscopic measurement device 1 captures a spectroscopic image of a sample S. More specifically, the spectroscopic measurement device 1 measures spectral data of Raman scattered light from the sample S.

[0025] The spectroscopic measurement device 1 includes a light source 11, a spatial light modulator 12, a dichroic mirror 13, a lens 16, a lens 22, a second fiber unit 40, a spectrometer 50, a processing device 60, a first fiber unit 70, and a portable unit 80.

[0026] The light source 11 is a laser light source that generates illumination light for spectroscopic measurement. The illumination light for spectroscopic measurement is simply referred to as illumination light L1. The light source 11 is a DPSS (Diode Pumped Solid State) laser that emits CW (Continuous Wave) light with a wavelength of 660 nm. Of course, the type and laser wavelength of the light source 11 are not particularly limited. In spectroscopic measurement, the illumination light L1 serves as excitation light that excites the sample S. Therefore, the light source 11 generates monochromatic illumination light L1.

[0027] Illumination light L1 from the light source 11 is incident on the spatial light modulator 12. The spatial light modulator 12 spatially modulates the illumination light L1 based on a control signal from the processing device 60. The spatial light modulator 12 controls the spatial distribution of the illumination light L1 on the sample S. This allows the area on the sample S onto which the illumination light L1 is incident to have a desired shape and size. For example, the spatial light modulator 12 modulates the illumination light L1 so as to illuminate only a region of interest (ROI) on the sample S.

[0028] The spatial light modulator 12 is a liquid crystal panel having pixels arranged in an array. The spatial light modulator 12 can modulate the phase of light by controlling the voltage applied to each pixel. The spatial light modulator 12 modulates the illumination light L1 to form a desired illumination pattern. Although FIG. 1 illustrates the spatial light modulator 12 as a transmissive liquid crystal device, a reflective liquid crystal device such as LCOS (Liquid Crystal on Silicon) can also be used as the spatial light modulator 12. Furthermore, the spatial light modulator 12 is not limited to a liquid crystal device, and a DMD or the like can also be used.

[0029] The illumination light L1 from the spatial light modulator 12 is incident on the dichroic mirror 13. The dichroic mirror 13 is a beam splitter that splits light. The dichroic mirror 13 splits the optical paths of the illumination light L1 and the observation light L2 (described later) based on the difference in wavelength. The dichroic mirror 13 transmits the wavelength of the illumination light L1. The illumination light L1 that has passed through the dichroic mirror 13 is incident on the lens 16. The illumination light L1 is incident on the first fiber unit 70 via the lens 16.

[0030] The first fiber unit 70 is a bundle fiber in which a plurality of fibers are bundled together. The first fiber unit 70 is an image fiber that transmits an image from the input end to the output end. The first fiber unit 70 is flexible.

[0031] The lens 16 forms an image of the illumination pattern formed by the spatial light modulator 12 on the incident end face 70a of the first fiber unit 70. At the incident end face 70a of the first fiber unit 70, the illumination light L1 is incident on some of the fibers according to the illumination pattern. That is, the illumination light L1 is incident only on the fibers corresponding to the ROI, and is not incident on the fibers other than those corresponding to the ROI.

[0032] The irradiation light L1 incident on the first fiber unit 70 from the incident end face 70a propagates through each fiber of the first fiber unit 70. The output end of the first fiber unit 70 is connected to the portable unit 80. Specifically, the output end of the first fiber unit 70 is coupled to a first port 811 of a portable housing 800 of the portable unit 80.

[0033] As shown in Fig. 2, the portable unit 80 includes a portable housing 800, an irradiation optical system 810, and a detection optical system 820. The irradiation optical system 810 and the detection optical system 820 are housed in the portable housing 800. The portable unit 80 has dimensions of approximately 14 cm x 16 cm x 4 cm. Therefore, the portable unit 80 is handheld. The field of view of the portable unit 80 is approximately 5 mm. The irradiation optical system 810 will be described below.

[0034] The irradiation optical system 810 includes a lens 812, a mirror 813, a mirror 815, a lens 816, a filter 817, and a dichroic mirror 818. The lens 812, the mirror 813, the mirror 815, the lens 816, the filter 817, and the dichroic mirror 818 are fixed to the portable housing 800.

[0035] A first port 811 and a second port 821 are provided on one side of the portable housing 800. A first fiber unit 70 is connected to the first port 811. The first fiber unit 70 is fixed to the first port 811 in a state aligned with the optical axis direction of the lens 812.

[0036] The illumination light L1 emitted from the exit end surface 70b of the first fiber unit 70 is incident on a mirror 813 via a lens 812. The illumination light L1 is reflected by mirrors 813 and 815 and incident on a filter 817. The illumination light L1 transmitted through the filter 817 is incident on a lens 816. The lens 816 forms an image of the exit end of the first fiber unit 70 on the sample S. The illumination light L1 from the lens 816 is incident on a dichroic mirror 818. The filter 817 is, for example, a short-pass filter having a cutoff wavelength longer than the laser wavelength of the light source 11. This prevents light with a wavelength longer than the laser wavelength from being irradiated onto the sample S and detected by the spectroscope during spectroscopic measurement. Furthermore, the filter 817 transmits observation light L2, which will be described later.

[0037] The dichroic mirror 818 is a beam splitter that splits the illumination light L1, observation light (described later), and signal light according to their wavelengths. For example, the dichroic mirror 818 reflects light of the laser wavelength of the illumination light L1 and transmits light of the wavelength of the signal light. Therefore, the dichroic mirror 818 reflects the illumination light L1 toward the sample S. The illumination light L1 reflected by the dichroic mirror 818 passes through the cylindrical tip 830 and is emitted to the outside of the portable housing 800.

[0038] The tip 830 may be provided with a transparent window 831. The window 831 is a parallel plate made of sapphire, calcium fluoride, quartz, or the like. Using these materials can reduce the amount of light emitted from the window 831. Furthermore, by appropriately selecting the window 831 from these materials, the Raman scattered light emitted from the window 831 can be wavelength-separated from the Raman scattered light emitted from the sample. The window 831 is provided to protect the dichroic mirror 818 and other components. The window 831 is replaceable on the tip 830. For example, if the window 831 becomes dirty, the dirty window 831 can be removed and a new window 831 can be installed. This prevents contamination of the dichroic mirror 818. This eliminates the need to replace components such as the dichroic mirror 818 and adjust the optical system. The tip 830 and the window 831 may be integrated, making the entire tip 830 replaceable.

[0039] The illumination light L1 transmitted through the window 831 is incident on the sample S. The illumination optical system 810 forms an image of the exit end surface 70b of the first fiber unit 70 on the sample S. Therefore, on the sample S, the illumination light L1 is irradiated only onto the ROI, as shown in FIG.

[0040] The position at which the illumination light L1 is incident is controlled by the spatial light modulator 12. The processing device 60 controls the spatial light modulator 12, thereby controlling the position at which the illumination light L1 is incident on the sample S. In other words, the processing device 60 controls the spatial light modulator 12, thereby illuminating only the ROI of the sample S.

[0041] As shown in FIG. 2 , the portable unit 80 may be provided with an observation illumination light source 18. For example, the observation illumination light source 18 is provided on the sample S side of the portable unit 80. Here, the observation illumination light source 18 is arranged on the outer periphery of the tip portion 830. The observation illumination light source 18 emits observation illumination light L4 toward the sample S to illuminate the sample S. The observation illumination light source 18 is, for example, a ring light such as an LED and has an annular shape. A non-monochromatic light source may be used for the observation illumination light source 18. The observation illumination light source 18 is arranged near the sample S to illuminate the sample S. Note that the observation illumination light source 18 is not limited to a ring light. The observation illumination light source 18 may be installed outside the portable unit 80. For example, as shown in the second embodiment, the observation illumination light source 18 may irradiate the sample S with the observation illumination light L4 from an oblique direction. Furthermore, the wavelength of the observation illumination light L4 may not overlap with the wavelength range of the Raman scattered light generated in the sample S. In this way, the spectroscope 50 can measure the Raman scattered light from the sample S while the observation illumination light source 18 continues to illuminate the sample S.

[0042] A portion of the observation illumination light L4 is reflected and scattered by the sample S and propagates through the irradiation optical system 810. The light reflected and scattered by the sample S and propagating through the irradiation optical system 810 becomes the observation light L2 in FIG. 1 . The observation light L2 propagates through the irradiation optical system 810 along the opposite optical path to that of the irradiation light L1. Specifically, the observation light L2 passes through the window 831 and enters the dichroic mirror 818. The observation light L2 reflected by the dichroic mirror 818 passes through a lens 816 and a filter 817 and then enters a mirror 815. The observation light L2 is then reflected by the mirrors 815 and 813 and enters a lens 812. The lens 812 forms an image of the observation light L2 on the exit end surface 70b of the first fiber unit 70.

[0043] The observation light L2 propagates through the first fiber unit 70 and is emitted from the incident end surface 70a of the first fiber unit 70. As shown in FIG. 1, the observation light L2 emitted from the first fiber unit 70 is incident on the dichroic mirror 13 via the lens 16. The observation light L2 reflected by the dichroic mirror 13 is formed into an image on the camera 23 by the lens 22. As a result, the camera 23 captures an optical image I of the sample.

[0044] The lens 22 is an imaging lens that forms an image of the incident end surface 70 a on the light receiving surface of the camera 23. The camera 23 is a two-dimensional photodetector such as a charge coupled device camera or a complementary metal oxide semiconductor (CMOS) image sensor. Therefore, the camera 23 can capture a two-dimensional optical image I of the sample S.

[0045] The processing device 60 is an information processing device such as a personal computer. The camera 23 outputs imaging data of the optical image I of the sample S to the processing device 60. The processing device 60 stores the imaging data of the optical image I in a memory or the like. In other words, the processing device 60 stores brightness data corresponding to the amount of light received by each pixel of the camera 23. The processing device 60 has a display or the like for displaying the optical image.

[0046] The user can extract an ROI of the sample S by checking the optical image captured by the camera 23. For example, the user can select an ROI on the display screen of the processing device 60. This identifies its coordinates in the optical image. The processing device 60 then controls the spatial light modulator 12 to illuminate the ROI identified by the user with the illumination light L1. This allows only the desired ROI to be illuminated. Alternatively, the processing device 60 may extract an ROI from the optical image using general-purpose image processing. The processing device 60 may also extract an ROI using an algorithm that detects an object with a specific spatial distribution. For example, the processing device 60 may extract an elongated object, such as a nerve, using image processing and set it as the ROI.

[0047] Next, a description will be given of the detection optical system 820, which forms the optical path of the signal light. As shown in FIG. 2, the detection optical system 820 includes a dichroic mirror 818, a lens 826, a filter 825, a filter 824, a mirror 823, and a lens 822.

[0048] When the illumination light L1 is irradiated onto the sample S, signal light L3 is generated. The signal light L3 generated by the sample S is incident on the dichroic mirror 818 via the window 831. That is, it passes through the hollow portion of the tip portion 830 and enters the portable housing 800. The signal light L3 passes through the dichroic mirror 818 and enters the lens 826. The signal light L3 from the lens 826 is incident on the filter 825 and the filter 824.

[0049] The filters 824 and 825 are optical filters that transmit a portion of the signal light L3 from the sample S. The filters 824 and 825 are wavelength filters that transmit or block light depending on the wavelength. Specifically, the filter 825 is an edge filter that blocks light of the laser wavelength. This prevents the signal light L3 of a wavelength different from the laser wavelength from being superimposed on the spectrometer 50 to which the second fiber unit 40 (described later) is connected. The filter 824 is a bandpass filter that transmits light of a predetermined wavelength band. Furthermore, the filter 824 limits the measurement wavelength range of the signal light L3 in the spectrometer 50.

[0050] The signal light L3 transmitted through the filter 824 is reflected by the mirror 823 and enters the lens 822. The signal light L3 from the lens 822 enters the second fiber unit 40. The lens 822 is an imaging lens, and forms an image of the sample S on the incident end face 411 of the second fiber unit 40. In other words, the incident end face 411 of the second fiber unit 40 is disposed at a position conjugate with the sample S.

[0051] The second fiber unit 40 is connected to the second port 821. The second fiber unit 40 is fixed to the second port 821 in a state aligned with the optical axis direction of the lens 822.

[0052] The second fiber unit 40 is a bundle fiber in which multiple fibers are bundled. The second fiber unit 40 is arranged in the optical path from the portable unit 80 to the spectrometer 50. The second fiber unit 40 includes an incident side holder 41, an output side holder 42, and a connection part 43. The incident side holder 41 is inserted into the second port 821. The arrangement of the fibers differs between the incident end face and the output end face of the second fiber unit 40.

[0053] The incident side holder 41 is, for example, a cylindrical holder and accommodates a plurality of fibers therein. The incident side holder 41 fixes the plurality of fibers on the incident end face 411 side of the second fiber unit 40. Therefore, the plurality of fibers are arranged adjacent to each other on the incident end face 411 side of the second fiber unit 40. Specifically, the plurality of fibers are arranged in a closely packed array.

[0054] The output side holder 42 is, for example, a cylindrical holder and houses a plurality of fibers therein. The output side holder 42 fixes the plurality of fibers on the output end face side of the second fiber unit 40. On the output end side of the second fiber unit 40, the plurality of fibers are arranged in a multi-line configuration with spaces between them. This enables spectroscopic measurement using a multifocal optical system.

[0055] The connecting portion 43 connects the incident side holder 41 and the output side holder 42. The connecting portion 43 is a flexible portion disposed between the incident side holder 41 and the output side holder 42. The configuration of the second fiber unit 40 will be described later.

[0056] The output end of the second fiber unit 40 is disposed on the input surface of the spectrometer 50. The signal light L3 propagated through the fiber of the second fiber unit 40 is output from the output end of the second fiber unit 40 and enters the spectrometer 50. The signal light L3 from the sample S enters the spectrometer 50 via the second fiber unit 40.

[0057] The spectrometer 50 includes a lens 51, a grating 52, a lens 54, and a photodetector 55. The signal light L3 from the second fiber unit 40 is incident on the lens 51. The lens 51 refracts the signal light L3 to form a parallel beam. The signal light L3 from the lens 51 is incident on the grating 52. The grating 52 is a wavelength dispersion element that disperses the signal light L3 according to its wavelength. The grating 52 has a diffraction angle according to the wavelength. The spectral direction of the signal light L3 by the grating 52 is defined as the X direction.

[0058] Here, the grating 52 is shown as a transmission type diffraction grating, and therefore the signal light L3 reflected by the grating 52 is incident on the lens 54. Note that the wavelength dispersion element is not limited to a transmission type diffraction grating, and may be a reflection type diffraction grating, a prism, or the like.

[0059] The signal light L3 wavelength-dispersed by the grating 52 enters the lens 54. The lens 54 focuses the signal light L3 on the light-receiving surface of the photodetector 55. The photodetector 55 is a two-dimensional array photodetector such as a CCD (Charge Coupled Device) camera or a CMOS (Complementary Metal Oxide Semiconductor) image sensor. The photodetector 55 has, for example, a plurality of pixels arranged along the X and Y directions. The X and Y directions are orthogonal to the optical axis of the optical system. In other words, the XY plane is a plane orthogonal to the optical axis. Of course, the X and Y directions, which are the pixel arrangement directions, do not have to be orthogonal to the Z direction. In other words, the focusing surface of the lens 54 does not have to be a plane orthogonal to the optical axis.

[0060] When the wavelength dispersion direction is the X direction, the X coordinate of the photodetector 55 corresponds to the wavelength and spatial position of the signal light L3. An image of the output end of the second fiber unit 40 is formed on the light receiving surface of the photodetector 55. The photodetector 55 can acquire spectral image information of the sample S dispersed by the spectroscope 50.

[0061] Next, the configuration of the second fiber unit 40 will be described with reference to Fig. 3. Fig. 3 is a diagram showing a schematic configuration of the second fiber unit 40.

[0062] The second fiber unit 40 has a plurality of fibers 45. An incident-side holder 41 fixes the plurality of fibers 45 at an incident end face 411 of the second fiber unit 40. The plurality of fibers 45 are arranged adjacent to each other at the incident end face 411 of the second fiber unit 40. For example, the fibers 45 are arranged so that the coating of one fiber 45 contacts the coating of an adjacent fiber 45. The outer shape of the fiber 45 including the coating is circular, and the plurality of fibers 45 are arranged so that each circle contacts the adjacent circle.

[0063] The incident end face 411 is positioned conjugate with the sample S. An image of the sample S is formed on the incident end face 411. In other words, the signal light L3 from one light irradiation spot on the sample is incident on one or more fibers 45. By arranging the fibers 45 close to each other, the gap between the fibers 45 can be reduced.

[0064] This makes it possible to reduce the area of ​​the sample S that cannot be spectroscopically measured. If the signal light L3 from the sample S enters the gaps between the fibers 45, the signal light L3 will not reach the spectrometer 50. By closely arranging the fibers 45, it is possible to reduce the area of ​​the gaps between the fibers 45. Therefore, it is possible to reduce the area of ​​the area that cannot be spectroscopically measured.

[0065] Non-Patent Document 5 (https: / / www.tem-inc.co.jp / products / detail-29.php) discloses a technique for numbering and mapping multiple fibers. Using this technique, it is possible to eliminate or reduce the gaps between fibers. By fusing the fibers, a honeycomb structure is formed, eliminating the gaps between the fibers. Adjacent fibers may also be bonded with an adhesive such as epoxy resin.

[0066] More specifically, 1,800 fibers 45 are arranged in a two-dimensional close-packed array at the incident end face 411. The multiple fibers 45 are arranged in a hexagonal close-packed array. Therefore, each fiber 45 is arranged so as to be in contact with six surrounding fibers 45. In other words, each of the multiple fibers 45 is in contact with six other fibers 45. Furthermore, the fibers 45 are not arranged in a matrix. In other words, the two arrangement directions at the incident end face 411 are not orthogonal to each other.

[0067] The incident side holder 41 holds the fibers 45 so that the fibers 45 are closely spaced on the incident end face 411 of the second fiber unit 40. In other words, the incident side holder 41 fixes the fibers 45 so that the fibers 45 are arranged adjacent to each other. In this way, the spectroscopic measurement of the sample S can be performed more appropriately.

[0068] A spectral image of the output end face 421 is formed on the light receiving surface of the photodetector 55. A plurality of fibers 45 are arranged in a multi-line configuration at intervals on the output end face 421. On the output end face 421, the output-side holder 42 holds the plurality of fibers 45 so that the plurality of fibers 45 are arranged at intervals from one another.

[0069] On the output end surface 421, a plurality of fibers 45 are arranged along the X direction and the Y direction. The plurality of fibers 45 are arranged in a two-dimensional matrix. The two arrangement directions on the output end surface 421 are not orthogonal. The plurality of fibers 45 are arranged at equal intervals in the X direction. Similarly, the plurality of fibers 45 are arranged at equal intervals in the Y direction. In this way, the output side holder 42 holds the plurality of fibers 45 so that the plurality of fibers 45 are arranged at regular intervals.

[0070] 1,800 fibers 45 are arranged in a 15 x 120 matrix. That is, the fibers 45 are arranged in 15 lines, with each line including 120 fibers 45. The 120 fibers 45 in each line are arranged parallel to the Y direction.

[0071] Specifically, 1,800 fibers 45 are arranged in a circular area with a diameter of about 2 to 3 mm on the incident end face 411. The core diameter of each fiber 45 is 40 μm, and the cladding diameter is 48 μm. On the sample S, a circular area with a diameter of about 80 μm is detected by the photodetector 55. In other words, a circular area with a diameter of about 80 μm is reduced and imaged on the incident end face 411 of the second fiber unit 40. Therefore, the photodetector 55 simultaneously detects the signal light L3 from the circular area with a diameter of 4 to 6 mm.

[0072] At the output end surface 421, 1800 fibers 45 are arranged in a rectangular area of ​​about 14 to 15 cm in the X direction and about 6 to 7 cm in the Y direction. Note that the output end surface 421 may be provided with multiple slits corresponding to the multiple lines.

[0073] The output-side holder 42 fixes the plurality of fibers 45 so that the plurality of fibers 45 are arranged at intervals on the output end face 421. The density of the plurality of fibers 45 on the input end face 411 is higher than the density of the plurality of fibers 45 on the output end face 421. In other words, the fibers 45 are sparsely arranged on the output end face 421, and the fibers 45 are densely arranged on the input end face 411.

[0074] Specifically, it is preferable that the density of the fibers 45 be 60% or more in the region where the fibers 45 are arranged. In other words, the fibers 45 are densely arranged so that 60% or more of the area in the region where the fibers 45 are arranged is occupied by the fibers 45. In other words, it is preferable that the area of ​​gaps between the fibers 45 is less than 40%. Furthermore, it is more preferable that the density of the region where the fibers 45 are arranged is 75% or more. In this case, the fibers 45 are densely arranged so that 75% or more of the area in the region where the fibers 45 are arranged is occupied by the fibers 45. It is preferable that the area of ​​gaps between the fibers 45 is less than 25%.

[0075] In this way, the signal light L3 emitted from adjacent fibers 45 is incident on the photodetector 55 without overlapping. In other words, the signal light L3 from different fibers 45 is detected by different pixels of the photodetector 55. In this way, the spectroscopic image can be measured appropriately.

[0076] As described above, the signal light L3 emitted from the second fiber unit 40 is split by the spectrometer 50. Here, the splitting direction of the spectrometer 50 is defined as the X direction. The pixel address in the X direction in the photodetector 55 indicates the split wavelength and the spatial position. The pixel address in the Y direction indicates the position in the multi-line.

[0077] The light receiving surface of the photodetector 55 will be described with reference to FIG. 4. FIG. 4 is a diagram showing an image on the light receiving surface of the photodetector 55. The pixels of the photodetector 55 are arranged in the X and Y directions. Furthermore, FIG. 4 schematically shows the fibers 45 included in one line. Here, the arrangement direction of the fibers 45 included in one line is parallel to the Y direction. The arrangement direction of multiple lines is parallel to the X direction. Therefore, the arrangement direction of the fibers 45 and the arrangement direction of the pixels are parallel. Furthermore, the spectral direction of the light emitted by the grating 52 is the X direction.

[0078] Therefore, the spectral data of one line of fibers 45 is measured in a band-shaped detection area on the light-receiving surface. In Figure 4, the detection area where the spectral data of the fibers 45 included in the first line is measured is shown as detection area D1. Similarly, the detection areas where the spectral data of the fibers 45 in the second to fifteenth lines are measured are shown as detection areas D2 to D15, respectively. Because one line includes 120 fibers 45, spectral data for 120 fibers can be measured in one detection area D1.

[0079] The detection regions D1 to D15 are arranged so as not to overlap one another. For example, the detection regions D1 and D2 are offset in the Y direction. Assume that the spectroscope 50 disperses the signal light on the long wavelength side to the +X side and the signal light L3 on the short wavelength side to the -X side. The pixel address corresponding to the longest wavelength in the detection region D1 is located on the -X side of the pixel address corresponding to the shortest wavelength in the detection region D2. Specifically, the filter 31 limits the wavelength range of the signal light L3 so that the detection regions D1 to D15 do not overlap. Furthermore, the spacing in the X direction of the fibers 45 at the output end face 421 is set to a predetermined value or more.

[0080] Furthermore, the fibers 45 are arranged at a distance from each other on the output end surface 421. For example, as shown in FIG. 3, the fibers 45 included in one line are arranged at intervals in the Y direction. Therefore, the signal light L3 from adjacent fibers 45 is incident on pixels at different Y direction addresses. The signal light L3 from each fiber 45 is detected at a different pixel. In other words, the signal light L3 from one fiber 45 is not incident on a pixel into which the signal light L3 from another fiber 45 is incident.

[0081] This design allows the signal light L3 from each fiber 45 to be detected without overlapping. Therefore, it is possible to measure the Raman spectra of multiple points on the sample S with a single shot (one frame) of the photodetector 55, without scanning the illumination light L1. This makes it possible to detect Raman scattered light from a two-dimensional area on a plane perpendicular to the optical axis.

[0082] Alternatively, the signal light from each fiber 45 may be detected so that it partially overlaps. In this case, the original spectrum can be restored using a mathematical technique such as compressed sensing. In this case, the signal light L3 from one fiber 45 can be wavelength-dispersed to more pixels. This allows the wavelength range that can be spectroscopically measured to be widened, or wavelength resolution to be improved.

[0083] The signal light L3 from each fiber 45 can be spectroscopically measured independently. This makes it possible to simultaneously spectroscopically measure the signal light L3 from 1,800 points on the sample S. In other words, a two-dimensional spectral image with 1,800 pixels can be captured in a short time. The signal light L3 from any one light irradiation spot (one location) on the sample S is incident on one fiber 45. Then, the spectrum of the signal light L3 emitted from one fiber 45 corresponds to the spectral data of one light irradiation spot (one location) on the sample S.

[0084] For example, the second fiber unit 40 has 1800 fibers 45. Therefore, the spectroscopic measurement device 1 can detect 1800 Raman spectra. In other words, the spectroscopic measurement device 1 can perform spectroscopic measurement of the signal light L3 from 1800 points on the sample S. Then, the processing device 60 generates a spectral image of the sample S based on the detection signal of the photodetector 55. In other words, the spectral image is generated based on 1800 pieces of spectral data. The process of generating the spectral image by the processing device 60 will be described below.

[0085] As described above, the incident side holder 41 and the output side holder 42 are connected by the connector 43. The connector 43 bundles the plurality of fibers 45 so that the fibers 45 can be deformed. Furthermore, the correspondence between the position of each fiber 45 on the incident end face 411 and the position of each fiber 45 on the output end face 421 is known. For example, the position of one fiber 45a on the incident end face 411 corresponds to the position of the fiber 45a on the output end face 421. Similarly, the position of another fiber 45b on the incident end face 411 corresponds to the position of the fiber 45b on the output end face 421.

[0086] In this way, the position of the exit end face 421 of a fiber 45 located at any position on the incident end face 411 is known. The processing device 60 stores information indicating the arrangement of each fiber 45. In other words, the processing device 60 stores the correspondence between the position of the fiber 45 on the incident end face 411 and the position on the exit end face 421. The processing device 60 then generates a spectral image from the detection results of the photodetector 55 by referencing the arrangement of each fiber 45. The processing device 60 rearranges the detection data for each pixel of the photodetector 55 so that it matches the fiber arrangement on the incident end face 411. In this way, the processing device 60 constructs a two-dimensional spectral image by two-dimensional mapping.

[0087] In this way, the fibers 45 are arranged more densely at the incident end face 411 than at the exit end face 421. Therefore, the photodetector 55 can detect the signal light L3 from more points on the sample S. If the position on the sample corresponds to an area where the fibers 45 are closely arranged, the signal light propagates through one of the fibers 45 and is detected by the photodetector 55.

[0088] Furthermore, because the light beams are arranged in a multi-line pattern on the output end surface 421, the spectrometer 50 can simultaneously perform spectroscopic measurement of the signal light L3 from a plurality of fibers 45. In other words, the signal light L3 emitted from a fiber 45 is detected independently of the signal light L3 emitted from other fibers 45. This allows the spectrometer 50 to perform spectroscopic measurement of the signal light L3 from a greater number of fibers 45. Furthermore, because the light beams are arranged in a multi-line pattern, more points can be measured.

[0089] The spectroscopic measurement device 1 can capture two-dimensional spectroscopic images without scanning laser light. This allows Raman spectroscopic images to be measured in a short time. Furthermore, since only the ROI is irradiated with laser, sample measurement with low phototoxicity is possible. Labeling with fluorescent substances or the like is not required, making label-free spectroscopic measurement possible. Furthermore, the signal light L3 from each fiber 45 is separated and detected. This allows spatial spectroscopic measurement without crosstalk.

[0090] Furthermore, because the spectroscopic measurement device 1 uses the portable unit 80, it can perform spectroscopic measurement of various samples. The portable unit 80 is connected to the flexible second fiber unit 40 and the first fiber unit 70. The user can install the portable unit 80 in a desired position and in a desired orientation. That is, the user can bring the portable unit 80 close to various samples S. The portable unit 80 can be installed not only for very small samples S that can be placed on a microscope stage, but also toward a person or the like. That is, the user simply fixes the portable unit 80 so that it faces the sample S. The user can perform spectroscopic measurement of various samples with the spectroscopic measurement device 1 having a simple configuration.

[0091] Next, a spectroscopic measurement method in the spectroscopic measurement device will be described. First, before spectroscopic measurement, an optical image is captured by optical observation using the camera 23. In optical observation, observation illumination light L4 from the observation illumination light source 18 illuminates the entire field of view of the lens 816. Then, the user or the processing device 60 extracts multiple points on the sample as ROIs based on the optical image. For example, the processing device 60 displays the optical image on a monitor. While viewing the optical image on the monitor, the user specifies a region of interest using a mouse or the like. The processing device 60 stores the coordinates of the specified region. In this way, the ROI is extracted.

[0092] The observation illumination light L4 for capturing an optical image is light from a light source different from that of the illumination light L1 used during spectroscopic measurement. In other words, the observation illumination light source 18 and the light source 11 can be switched between when capturing an optical image and when performing spectroscopic measurement.

[0093] The spatial light modulator 12 controls the beam of illumination light L1 from the light source 11 so as to selectively illuminate the ROI on the sample S. The spatial light modulator 12 modulates the illumination light L1 so that the illumination light L1 is incident only on the ROI. In other words, the spatial light modulator 12 modulates the illumination light L1 so that the illumination light L1 is not irradiated on areas other than the ROI. This allows multiple points extracted as the ROI to be illuminated simultaneously.

[0094] The processing device 60 generates a binary image for controlling the spatial light modulator 12. In the binary image, for example, a position that is the ROI is represented by 1, and a position that is not the ROI is represented by 0. The processing device 60 outputs computer generated hologram (CGH) data obtained by Fourier transforming the control binary image to the spatial light modulator 12. In this manner, the processing device 60 outputs the hologram to the spatial light modulator 12. The spatial light modulator 12 has a plurality of control pixels and diffracts incident light. The spatial light modulator 12 can control the phase of the diffracted wave for each pixel.

[0095] By using the spatial light modulator 12, it is possible to form multi-focuses on any multiple points on the sample S. In other words, since the irradiation light L1 is focused only on the ROI, it is possible to prevent Raman scattered light from occurring outside the ROI. This enables measurements with a high S / N ratio and measurements with little spatial crosstalk. Furthermore, since light is not irradiated outside the ROI, phototoxicity to the sample S can be reduced.

[0096] The connective tissue and nerves of the biological sample are extracted as the ROI. Therefore, the spatial light modulator 12 modulates the illumination light L1 so that only the connective tissue and nerves are selectively illuminated. The signal light L3 from the ROI is incident on the spectroscope 50 via the detection optical system 820 and the second fiber unit 40. The spectroscope 50 performs spectroscopic measurement of the signal light L3 from the location illuminated by the illumination light L1. The processing device 60 generates a spectroscopic image based on the spectral measurement results of the spectroscope 50.

[0097] Example 1 Fig. 5 is a diagram for explaining Example 1 of the spectroscopic measurement device. In Fig. 5, a holding mechanism 81 is provided to hold a portable unit 80. A sample S is placed on, for example, a table. The holding mechanism 81 holds the portable unit 80 above the sample S. This fixes the position of the portable unit 80 relative to the sample S.

[0098] The sample S is, for example, tissue excised from a rat. The sample S includes nerves, muscle tissue, connective tissue, etc. By observing the optical image, the nerves, muscle tissue, and connective tissue are extracted as identification targets. The nerves, muscle tissue, and connective tissue are set as ROIs, and the irradiation light L1 is selectively irradiated thereon.

[0099] The spectroscopic measurement device 1 measures the spectrum of the Raman scattered light for each ROI. The processing device 60 then analyzes the spectrum to distinguish between nerves, muscle tissue, and connective tissue. The processing device 60 can map the discrimination results onto the optical image I and display it on a monitor. The processing device 60 can also visualize and display nerves. For example, nerve-connective tissue / muscle tissue discrimination can be performed with 96.7% accuracy and 100% sensitivity.

[0100] 6 is a schematic diagram showing an example of implementation of the spectroscopic measurement device 1 of Example 1. The spectroscopic measurement device 1 includes a main body 82. The main body 82 includes the light source 11, the spatial light modulator 12, the dichroic mirror 13, the lens 16, the lens 22, the camera 23, the spectrometer 50, and the like, all of which are shown in FIG. 1 . In this example, the main body 82 includes a wagon with casters. The second fiber unit 40 and the first fiber unit 70 are provided between the main body 82 and the portable unit 80.

[0101] The user U can use the spectroscopic measurement device 1 for diagnosis, examination, and surgery on humans or animals. The user U can use the portable unit 80 as a small probe for observing the affected area. The main body 82 is installed near the operating table. This allows the user to freely move the spectroscopic measurement device 1 within the operating room. The holding mechanism 81 is an arm mechanism that holds the portable unit 80 in the opening of the surgical subject. The portable unit 80 irradiates the irradiation light L1 onto the affected area, etc.

[0102] As described in FIG. 5 , the processing device 60 identifies nerves, muscle tissue, and connective tissue based on the Raman spectroscopy spectrum. The monitor 61 then displays the optical image I captured by the camera 23. The monitor 61 visualizes and displays the nerves. For example, the processing device 60 can highlight the nerves by applying a desired color. The user, who is the surgeon, can identify the location of the nerves. The measurement results of the spectroscopic measurement device 1 can assist the user U in making decisions. Therefore, the user can be appropriately assisted in medical diagnosis, examination, and surgery.

[0103] Second Embodiment The configuration of a spectroscopic measurement device 1 according to a second embodiment will be described with reference to Fig. 7 . Fig. 7 is a schematic diagram showing the overall configuration of the spectroscopic measurement device 1. The spectroscopic measurement device 1 includes a spectroscopic illumination optical system 10, an observation illumination light source 18, an observation optical system 20, a spectroscopic measurement optical system 30, a second fiber unit 40, a spectroscope 50, and a processing device 60. Note that the second fiber unit 40, the spectroscope 50, the processing device 60, etc. are the same as those in the first embodiment, and therefore their description will be omitted where appropriate. This embodiment differs from the first embodiment in that a portable unit 80 and a first fiber unit 70 are not provided.

[0104] First, the spectroscopic illumination optical system 10 will be described. The spectroscopic illumination optical system 10 is an optical system for guiding the illumination light L1 to the sample S. The spectroscopic illumination optical system 10 includes a light source 11, a spatial light modulator 12, a dichroic mirror 13, a dichroic mirror 14, and a lens 15. The light source 11, the spatial light modulator 12, and the dichroic mirror 13 are the same as those in the first embodiment, and therefore their description will be omitted. The dichroic mirror 13 reflects the illumination light L1 toward the dichroic mirror 14.

[0105] The dichroic mirror 14 splits the light according to its wavelength. The dichroic mirror 14 transmits the wavelength of the illumination light L1. Therefore, the illumination light L1 that has passed through the dichroic mirror 14 is incident on the lens 15. The lens 15 is an objective lens that focuses the illumination light L1 onto the sample S. This illuminates the sample S with the illumination light L1. Furthermore, the illumination light L1 is modulated by the spatial light modulator 12. Therefore, the illumination light L1 can illuminate a desired area on the sample S. The sample S is placed on a stage (not shown) or the like. The stage may be a movable stage in order to change the illumination position of the sample S.

[0106] Next, the observation illumination light source 18 and the observation optical system 20 will be described. The observation illumination light source 18 is, for example, a lamp light source, and generates white observation illumination light L4. The observation illumination light L4 from the observation illumination light source 18 illuminates the sample S. Of course, the observation illumination light source 18 is not limited to a white lamp light source. A light source that is not monochromatic can also be used as the observation illumination light source 18.

[0107] The observation optical system 20 is an optical system for guiding observation light L2 from the sample S to the camera 23. The observation light L2 is light from an area illuminated with observation illumination light L4. For example, the observation light L2 is scattered light scattered by the sample S, reflected light reflected by the sample S, or fluorescence generated by the sample S. The observation optical system 20 includes a lens 15, a dichroic mirror 14, a dichroic mirror 13, a filter 21, and a lens 22.

[0108] Observation light L2 from the sample S is refracted by the lens 15 and enters the dichroic mirror 14. Observation light L2 transmitted through the dichroic mirror 14 enters the dichroic mirror 13. Observation light L2 transmitted through the dichroic mirror 13 enters the filter 21.

[0109] The filter 21 is an optical filter that transmits a portion of the light from the sample S. Specifically, the filter 21 is a wavelength filter that transmits or blocks light depending on the wavelength. This allows the camera 23, which will be described later, to detect only the observation light L2 of a desired wavelength. In other words, the light of the wavelength that transmits through the dichroic mirror 14, the dichroic mirror 13, and the filter 21 becomes the observation light L2.

[0110] The observation light L2 transmitted through the filter 21 passes through the lens 22 and is detected by the camera 23. As a result, an optical image I of the sample S is captured. The lens 22 and the camera 23 are the same as those in the first embodiment, and therefore a description thereof will be omitted.

[0111] The dichroic mirror 14 may be disposed so as to be insertable into or removable from the optical path. The dichroic mirror 14 may be removed from the optical path when observing the optical image of the sample S. In other words, the dichroic mirror 14 may be inserted into the optical path when performing spectroscopic measurement.

[0112] Next, the spectroscopic measurement optical system 30 will be described. The spectroscopic measurement optical system 30 is an optical system from the sample S to the photodetector 55 of the spectroscope 50. In other words, the spectroscopic measurement optical system 30 guides the signal light L3 generated in the sample S to the photodetector 55. The spectroscopic measurement optical system 30 includes a lens 15, a dichroic mirror 14, a filter 31, a lens 32, a second fiber unit 40, and a spectroscope 50. The second fiber unit 40 and the spectroscope 50 are the same as those in the first embodiment, and therefore their description will be omitted.

[0113] The signal light L3 generated by the sample S is incident on the lens 15. The signal light L3 refracted by the lens 15 is incident on the dichroic mirror 14. The dichroic mirror 14 transmits light of the laser wavelength. The dichroic mirror 14 reflects the signal light L3, which has a wavelength different from that of the irradiation light L1, toward the filter 31.

[0114] The signal light L3 reflected by the dichroic mirror 14 is incident on the filter 31. The filter 31 is an optical filter that transmits a portion of the light from the sample S. Specifically, the filter 31 is a wavelength filter that transmits or blocks light depending on the wavelength. Specifically, the filter 31 is a bandpass filter that blocks light of the laser wavelength of the light source 11 and transmits light in a predetermined wavelength band. This allows the spectroscope 50, which will be described later, to perform spectroscopic measurement of the signal light L3 having a wavelength different from the laser wavelength.

[0115] The signal light L3 transmitted through the filter 31 is incident on the lens 32. The lens 32 is an imaging lens, and forms an image of the sample S on the incident end of the second fiber unit 40. In other words, the incident end face of the second fiber unit 40 is disposed in a position conjugate with the sample S. The second fiber unit 40 has a plurality of fibers, and guides the incident signal light L3 to the spectrometer 50. This allows spectroscopic measurement of the Raman scattered light from the sample S, similar to the first embodiment.

[0116] (Fiber Arrangement) Next, the fiber arrangement will be described with reference to Fig. 8 and Fig. 9. Fig. 8 and Fig. 9 are XY plan views schematically showing the range in which the signal light dispersed by the diffraction grating is detected by the photodetector 55. Note that, apart from the fiber arrangement, the same configuration as in the first embodiment can be used, and therefore a description thereof will be omitted.

[0117] In FIG. 8, 10 fiber rows are provided in the X direction. In FIG. 8, the line closest to the -x side is the first line, and the line closest to the +x side is the tenth line. In FIG. 8, the number of fibers in each line is the same. Specifically, 200 fibers 45 are provided in one line. That is, 200 fibers 45 are arranged in each line along the Y direction. The total number of fibers 45 in the second fiber unit 40 is 2000 (=200×10). The multiple fibers 45 are arranged at equal intervals in the Y direction. Furthermore, the respective pitches are arranged at equal intervals in the X direction.

[0118] The fiber diameter of each fiber 45 is 55 μm for the coating, 48 μm for the cladding, and 40 μm for the core. The length of one line in the Y direction is 11 mm (55 μm × 200 lines). The pixel size of the photodetector 55 is 11 μm × 11 μm. The sensor size of the photodetector 55 is 22.528 mm × 22.528 mm. The number of pixels required in the Y direction is 1000 (11 mm / 11 μm).

[0119] Assume that one line of signal light is dispersed into 100 columns of pixels. In other words, the signal light from one fiber 45 is dispersed into 100 pixels by the spectroscope 50 and detected. Therefore, the number of pixels required in the X direction is 1000 (100 pixels x 10 lines). The size of the exit end face in the X direction is 11 mm (1000 pixels x 11 μm). Since the size of the exit end face 421 in the XY plane is 11 x 11 mm, the diagonal size is 15.56 mm.

[0120] In contrast, in FIG. 9 , the number of fibers in each line is different. In FIG. 9 , 11 fiber rows are provided. The number of fibers in one line is smallest at both ends in the X direction, and increases toward the center. The number of fibers in one line decreases toward both ends in the X direction. Specifically, starting from the line on the -x side, the number of fibers in one line is 90, 155, 192, 216, 230, 237, 230, 216, 192, 155, and 90. Therefore, the total number of fibers 45 is 2003. The fibers 45 are arranged symmetrically with respect to the sixth line in the center.

[0121] The maximum number of fibers per line is 237. The maximum length in the Y direction at the output end surface 421 is 13.035 mm (55 μm × 237 fibers). The number of pixels required in the Y direction is 1185 (= 13.035 mm / 11 μm). The number of fiber rows is 11. The length in the X direction is 11 mm before splitting and 12.1 mm after splitting. In the spectrometer 50, the signal light L3 is dispersed into 100 pixels per line and detected. The number of pixels required in the X direction is 1100 (100 pixels × 11 lines).

[0122] The fibers 45 are arranged so that the outer shape of the exit end face 421 is circular or elliptical. The diagonal length of the exit end face 421 is 13.08 mm. Therefore, the diagonal length can be reduced by approximately 16% compared to the configuration of FIG. 8. By reducing the diagonal size in this way, the optical system of the spectrometer 50 can be made more compact. Furthermore, the effects of lens aberrations and lens-induced vignetting in the spectrometer 50 can be reduced. The imaging performance and light detection efficiency of the optical system can be improved, enabling highly accurate spectroscopic measurement. Note that the fiber arrangements shown in FIG. 8 or FIG. 9 can also be applied to the configuration of embodiment 1.

[0123] Example: Figure 10 shows images of the input and output ends of a fiber. At the input end of fiber 45, approximately 1,700 fibers are densely arranged. At the output end of fiber 45, a periodic multi-line arrangement is formed. At the output end of fiber 45, each line is arranged at a predetermined interval. Figure 10 also shows an image obtained when signal light from the output end of the fiber is detected by a spectrometer. The image in Figure 10 is captured by the two-dimensional array detector of the spectrometer. The Raman spectrum is measured by separating the signal light passing through each fiber strand.

[0124] Figure 11 shows the results of measuring PDMS (Polydimethylsiloxane) and PE (polyethylene). The wavelength of the excitation light is 660 nm, and the data acquisition time is 5 seconds. As shown in the sample image in Figure 11, the sample contains PDMS and PE. PDMS and PE are detected at different pixels, allowing their respective Raman spectra to be detected. A spectral image reconstructed from the Raman spectra is shown here. Here, the PE peak at a wavenumber of 2848 cm is －１ is shown in green, and the wavenumber of the PDMS peak is 2973 cm －１ A color image is constructed in which the color is shown in magenta.

[0125] Figure 12 shows a microscope image and a spectral image when the entire ROI is irradiated with excitation light. Figure 12 shows a spectral image of a sample containing PDMS (Polydimethylsiloxane) and PE (polyethylene). In Figure 12, the PE peak wavenumber of 2848 cm －１ is shown in green, and the wavenumber of the PDMS peak is 2973 cm －１ A color image is constructed in which the color is shown in magenta.

[0126] FIG. 13 shows the measurement results of a sample containing PS (polystyrene) and PVC (polyvinyl chloride). It shows a bright-field image of the sample and a frame image of a spectroscopic camera. Furthermore, FIG. 13 shows a Raman spectrum after noise component removal by SVD (Singular Value Decomposition) processing, and a spectroscopic image constructed from the Raman spectrum. In the spectroscopic image, the peak wavenumber of PS is 2904 cm. －１ Intensity I ２９０４ and the peak wave number of PVC is 2914 cm －１ Raman scattered light intensity I ２９１４ Ratio to (= I ２９０４ / I ２９１４ The color of the spectral image changes depending on the Raman scattered light intensity ratio.

[0127] (Discrimination Method) Next, a method for discriminating the components of a sample in the above-described spectroscopic measurement device 1 will be described. Specifically, the processing device 60 analyzes the components of the sample by performing principal component analysis. In this measurement, the sample is rat tissue, and the number of measured samples is 214. Of the 214 samples, 52 samples are nerve bundles, 54 samples are tendons, 54 samples are muscle tissues, and 54 samples are adipose tissues.

[0128] The laser was exposed for 10 seconds for measurement. Five laser spots were formed on one sample. Spectra were measured using signal light from each spot, resulting in a total of 1,070 measurement points. In other words, 1,070 Raman spectra were measured. Furthermore, 260 Raman spectra were measured for the nerve bundle.

[0129] Fig. 14 is a flowchart showing a method for identifying components of a sample based on multiple Raman spectra. The method shown in Fig. 14 can be executed by a program in a processing device 60 such as a personal computer. Below, we will explain a method for determining whether a measurement point of a spectrum represents a nerve. Of course, the following identification method can also be applied to components other than nerves.

[0130] First, the processing device 60 removes the sensor bias in the photodetector 55 of the spectrometer 50 (S11). For example, the processing device 60 removes the bias by subtracting data obtained when the shutter of the photodetector 55 is closed from the measured spectrum data.

[0131] Next, the processing device 60 removes the background (S12). Here, data due to background light other than Raman scattered light is removed. Next, the processing device 60 calibrates the spectral response and wavenumber (S13). For example, the processing device 60 calibrates the spectral response due to variations in sensor pixels, etc. Furthermore, the wavenumber of the spectrum is calibrated. The processing device 60 calculates the L2 norm and normalizes the calibrated spectrum based on the L2 norm (S14). Note that the processes of S11 to S14 can be performed using known techniques, and therefore detailed explanations will be omitted.

[0132] Next, the processing device 60 performs principal component analysis on the multiple spectra (S15). FIG. 15 is a graph showing the results obtained by the principal component analysis. FIG. 15 shows a graph showing the principal component vectors of the first to tenth principal components, as well as a graph showing the contribution rate of each principal component. Note that the graph of the principal component vectors shows the principal component vectors offset. Here, an example is described in which nerves are identified based on the scores of the first to fifth principal components, which have the largest contribution rates. Note that the order of the principal components used for identification can be changed as appropriate based on the contribution rate and cumulative contribution rate.

[0133] Fig. 16 is a box plot of the scores of the first to fifth principal components of the Raman spectrum at 1070 measurement points. In Fig. 16, N indicates nerve bundles, M indicates muscle tissue, C indicates tendons, and A indicates adipose tissue. Furthermore, Fig. 16 shows boxes containing the median and data within ±25% of the median.

[0134] The processing device 60 then determines whether the sample is a nerve (N) and verifies the determination based on the scores of the first to fifth principal components (S16). For example, the processing device 60 performs machine learning to determine a discriminant based on the scores of the first to fifth principal components obtained from multiple spectra. The processing device 60 calculates the discriminant by performing machine learning using 1,069 of the 1,070 spectra as learning data (also referred to as training data). For example, when the scores of the first to fifth principal components are used, the discriminant is determined based on the boundaries in the five-dimensional score space. Here, the processing device 60 determines the discriminant by linear discriminant analysis.

[0135] Specifically, the components of the sample are known at all measurement points. In other words, it is known whether the spectrum is a nerve spectrum or a non-nerve spectrum. Here, the processing device performs supervised machine learning using 1,069 spectra as training data. The processing device 60 then evaluates whether the remaining spectrum can be correctly discriminated using the discriminant generated by machine learning. The accuracy of the discrimination is verified by sequentially changing the spectrum to be verified. Then, the processing device 60 performs machine learning based on the verification results to build a more accurate model.

[0136] FIG. 17 is a table showing the results of discrimination using the discriminant. In FIG. 17, the discrimination results when discriminating each measurement point using the discriminant are shown as prediction. As described above, 260 of the 1,070 measurement points are classified as nerve, and 810 points are classified as non-nerve. As described above, the processing device 60 calculates the discriminant by machine learning. The processing device 60 uses the discriminant to make discrimination based on the scores of the first to fifth principal components.

[0137] Of the spectra obtained from nerves, 203 measurement points were classified as nerves by the discriminant, and 57 measurement points were classified as non-nerve. Therefore, the sensitivity to nerves was 78.1% (= 203 / 260). Furthermore, of the spectra obtained from non-nerve, 776 measurement points were classified as non-nerve by the discriminant, and 34 measurement points were classified as nerves. Therefore, the specificity to non-nerve was 95.8% (= 776 / 810). Therefore, the accuracy of the classification was 91.5% (= (203 + 776) / 1070).

[0138] FIG. 18 is a table showing the discrimination results when five spectra obtained from a single exposure are collectively discriminated. Here, if one of the five spectra (hereinafter referred to as the discrimination threshold) or more is discriminated as nerve, all five points of the sample are discriminated as nerve. The processing device 60 counts the number of spectra discriminated as nerve among the spectra of the five measurement points acquired simultaneously. Then, if the spectrum count number is equal to or greater than the discrimination threshold, the processing device 60 discriminates all five measurement points as nerve. If the spectrum count number is less than the discrimination threshold, the processing device 60 discriminates all five measurement points as non-nerve.

[0139] As shown above, there are 52 neural samples and 162 non-neural samples. Of the 52 samples, 51 samples were classified as neural and 1 sample was classified as non-neural. Therefore, the sensitivity to neural samples is 98.1% (= 51 / 52). Furthermore, of the 162 non-neural samples, the discriminant classified 136 samples as non-neural and 26 samples as neural. Therefore, the specificity to non-neural samples is 84.0% (= 136 / 162). Therefore, the accuracy of the classification is 87.4% (= (51 + 136) / 214).

[0140] Furthermore, the verification results when the discrimination threshold is changed to 0, 1, 2, 3, 4, and 5 will be described using FIG. 19 . In FIG. 19 , the discrimination thresholds of 0, 1, 2, 3, 4, and 5 are shown as discrimination threshold ratios. That is, the discrimination thresholds of 0, 1, 2, 3, 4, and 5 are shown as 0.0 (= 0 / 5), 0.2 (= 1 / 5), 0.4 (= 2 / 5), 0.6 (= 3 / 5), 0.8 (= 4 / 5), and 1.0 (= 5 / 5), respectively. For example, when the discrimination threshold is 2, if two or more (40% or more) of the five measurement points are discriminated as nerves by the discriminant, all five measurement points are discriminated as nerves.

[0141] In the table shown in FIG. 19 , discrimination as a nerve is referred to as positive, and discrimination as a non-nerve is referred to as negative. Correct discrimination is referred to as True, and misdiscrimination is referred to as False. Therefore, discrimination of a nerve sample as a nerve is referred to as TP (True positive), and misdiscrimination of a nerve sample as a non-nerve is referred to as FN (False negative). Discrimination of a non-nerve sample as a non-nerve is referred to as TN (True negative), and misdiscrimination of a non-nerve sample as a nerve is referred to as FP (False positive).

[0142] For example, when the discrimination threshold is 0 (0.0), all 214 samples are classified as neural (positive). Therefore, TP is 52 and FP is 162. Furthermore, FN and TN are 0. The sensitivity, specificity, and accuracy are shown when the discrimination threshold is changed. By setting the discrimination threshold appropriately, discrimination with higher accuracy can be achieved. Higher accuracy can be obtained than when each measurement point is discriminated separately.

[0143] In this way, the spectroscopic measurement device 1 measures multiple spectra by detecting signal light from multiple points on the sample with a spectroscope. The processing device 60 calculates scores of the principal components by performing principal component analysis on the multiple spectra. The processing device 60 uses the scores of the principal component analysis to identify the components contained in the sample. In this way, the components of the sample can be identified with high accuracy. In other words, the components at the measurement points of the spectrum can be identified.

[0144] Furthermore, prior to the above discrimination, the spectroscopic measurement device 1 may calculate a discriminant. For example, the processing device 60 may calculate the discriminant through machine learning. A sample with known components is used as a reference sample. The spectroscopic measurement device 1 measures multiple spectra by spectroscopically measuring the reference sample. Here, the spectrum obtained from the reference sample is used as a training spectrum (training data). The training spectrum becomes training data with a correct answer label. The processing device 60 then performs supervised machine learning using the multiple training spectra as training data. In machine learning, a discriminant is calculated to improve the discrimination accuracy of the training spectrum. This allows the components of a sample to be accurately discriminated based on the spectrum of the sample with unknown components. The processing device 60 can determine principal component axes by performing principal component analysis on a reference sample with known components. The processing device 60 may then apply the determined principal component axes to an unknown sample to calculate principal component scores.

[0145] Furthermore, part or all of the processing in the processing device 60 described above can be realized as a computer program. Such a program can be stored and supplied to a computer using various types of non-transitory computer-readable media. Non-transitory computer-readable media include various types of tangible recording media. Examples of non-transitory computer-readable media include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, and semiconductor memories (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, and RAMs (Random Access Memory)). Furthermore, the program may be supplied to a computer by various types of temporary computer-readable media. Examples of temporary computer-readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire or an optical fiber, or via a wireless communication path.

[0146] The invention made by the inventor has been specifically described above based on an embodiment, but it goes without saying that the present invention is not limited to the above embodiment and can be modified in various ways without departing from the gist of the invention.

[0147] This application claims priority based on Japanese Patent Application No. 2023-111741, filed on July 6, 2023, the disclosure of which is incorporated herein in its entirety.

[0148] REFERENCE SIGNS LIST 1 Spectroscopic measurement device 11 Light source 12 Spatial light modulator 13 Dichroic mirror 16 Lens 18 Observation illumination light source 20 Observation optical system 21 Filter 22 Lens 23 Camera 30 Spectroscopic measurement optical system 31 Filter 32 Lens 40 Second fiber unit 41 Incident side holder 42 Exit side holder 45 Fiber 50 Spectrometer 51 Lens 52 Grating 54 Lens 55 Photodetector 60 Processing device 70 First fiber unit 80 Portable unit 800 Portable housing 810 Irradiation optical system 811 First port 820 Detection optical system 821 Second port 831 Window L1 Irradiation light L2 Observation light L3 Signal light L4 Observation illumination light

Claims

1. A light source that generates irradiating light, The first fiber unit into which the aforementioned irradiated light is incident, A portable unit to which the first fiber unit is connected, The portable unit houses an irradiation optical system that guides the irradiation light emitted from the first fiber unit to the sample, A detection optical system housed in the portable unit guides signal light from the sample irradiated with the illumination light, A spectrometer that spectrally analyzes the aforementioned signal light and detects it with a two-dimensional array photodetector, A second fiber unit connected to the portable unit and having a plurality of fibers that guide the signal light from the detection optical system to the spectrometer, wherein at the input end face of the second fiber unit, the plurality of fibers are arranged adjacent to each other, and at the output end face of the second fiber unit on the spectrometer side, the plurality of fibers are arranged in a multi-line pattern with spacing between them, A camera for capturing an optical image of the aforementioned sample, The system includes a processing unit that generates a spectral image of the sample from the detection results of the two-dimensional array photodetector by referring to the arrangement relationship of the plurality of fibers at the incident end face and the exit end face of the second fiber unit, A spectroscopic measuring device in which multiple points on the sample extracted based on the optical image are selectively illuminated.

2. The system further includes a spatial light modulator that spatially modulates the light emitted from the aforementioned light source, The spectroscopic measuring apparatus according to claim 1, wherein the irradiation light modulated by the spatial light modulator is incident on the first fiber unit.

3. It further includes an observation illumination light source that generates observation illumination light, Observation light from the sample illuminated by the observation illumination light propagates through the illumination optical system and enters the first fiber unit. The spectroscopic measuring apparatus according to claim 1, wherein the camera detects the observation light emitted from the first fiber unit.

4. The spectroscopic measuring apparatus according to claim 3, wherein the observation illumination light source is a ring illumination provided at the tip of the portable unit on the sample side.

5. The spectroscopic measuring apparatus according to claim 2, wherein the incident end face of the second fiber unit is positioned conjugate to the sample.

6. The spectroscopic measuring apparatus according to claim 1, wherein the tip of the portable unit is provided with a window that transmits the irradiation light and the signal light.

7. The spectroscopic measuring apparatus according to claim 1, wherein at the exit end face of the second fiber unit, the number of fibers included in one line decreases towards both ends in the direction corresponding to the dispersion direction of the spectrometer.

8. A light source that generates illumination light, A spectrometer that spectrally analyzes the signal light from a sample illuminated by the aforementioned illumination light and detects it with a two-dimensional array photodetector, A fiber unit having a plurality of fibers arranged in the optical path from the sample to the spectrometer, wherein at the input end face of the fiber unit, the plurality of fibers are arranged adjacent to each other, and at the output end face, the plurality of fibers are arranged in a multi-line pattern with spacing between them, The system includes a processing unit that generates a spectral image of the sample from the detection results of the two-dimensional array photodetector by referring to the arrangement relationship of the plurality of fibers at the incident end face and the exit end face of the fiber unit, A spectroscopic measuring device in which, at the exit end face of the fiber unit, the number of fibers included in one line decreases towards both ends in the direction corresponding to the dispersion direction of the spectrometer.

9. By detecting the signal light from multiple points of the sample using the spectrometer, multiple spectra are measured. By performing principal component analysis on the aforementioned multiple spectra, the scores of the principal components are calculated. A spectroscopic measuring apparatus according to any one of claims 1 to 8, which uses the score of the principal component analysis to determine the components contained in the sample.

10. By detecting signal light from multiple points of a reference sample whose components are known using the spectrometer, multiple training data are obtained. The spectroscopic measuring apparatus according to claim 9, which calculates a discriminant formula for distinguishing the components by performing supervised learning using the aforementioned training data.

11. The steps include generating illumination light from a light source, The steps include: irradiating the first fiber unit connected to the portable unit with the irradiation light; The steps include: guiding the irradiation light emitted from the first fiber unit to the sample using an irradiation optical system housed in the portable unit; The steps include: igniting the detection optical system provided in the portable unit with signal light from the sample; The step of injecting the signal light propagated through the detection optical system into the incident end face of a second fiber unit connected to the portable unit, where a plurality of fibers are arranged adjacently; The step of emitting the signal light from the output end face of the second fiber unit, in which the plurality of fibers are arranged in a multi-line configuration with spacing between them, The steps include: spectrally analyzing the signal light emitted from the aforementioned exit end face and detecting it with a two-dimensional array photodetector; The steps include capturing an optical image of the sample using a camera, The process includes the step of generating a spectral image of the sample from the detection result of the two-dimensional array photodetector by referring to the arrangement relationship of the plurality of fibers at the incident end face and the exit end face of the second fiber unit, A spectroscopic measurement method in which multiple points on the sample extracted based on the optical image are selectively illuminated.

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