JP2014095568A - Spectroscopic probe and spectroscopic instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spectroscopic probe that is able to make spatial resolution higher and to provide a spectroscopic instrument that has the same.SOLUTION: A spectroscopic probe 10 according to one embodiment comprises: an excitation fiber 11 configured to guide excitation light to a specimen 20; and a detection fiber 15 that is subjected to signal light from the specimen 20. The end face of the sample-side leading end of either the excitation fiber or detection fiber is formed obliquely with respect to a fiber axis such that a spatial resolution of not greater than 1.0 mm is obtained, the spatial resolution being based on an analysis area 32 where the emission area 30 of excitation light emitted from the sample-side end face 11a of the excitation fiber overlaps the light receiving area 31 of the detection fiber. Additionally, the excitation fiber and the detection fiber are arranged.

Description

  The present invention relates to a spectroscopic probe and a spectroscopic device.

  As a spectroscopic probe used in a spectroscopic device, there are probes described in Patent Document 1 and Non-Patent Document 1. The probe described in Patent Document 1 and the like includes an excitation fiber that propagates excitation light that excites a sample, and a detection fiber that receives signal light (for example, scattered light) from the sample. Usually, the excitation fiber and the detection fiber are arranged so that their fiber axes are substantially parallel on the sample side, as described in Patent Document 1 and the like.

  Thus, in a spectroscopic probe including an excitation fiber and a detection fiber, an irradiation region of excitation light emitted from the excitation fiber and a range in which light can enter the detection fiber (hereinafter referred to as a light receiving region) It is possible to detect the signal light from the sample in the region where the and overlap. Therefore, the overlapping region between the irradiation region and the light receiving region is an analysis region analyzed by spectroscopy.

JP 2004-294109 A

Yuichi Komachi, Takashi Katagiri, Hidetoshi Sato, and Hideo Tashiro, “Improvement and analysis of a micro Ramanprobe,” APPLIED OPTICS, Optical Society of America, 20 March 2009, Vol.48, No.9, pp.1683-1696

  In some cases, a sample to be spectrally analyzed using a spectroscopic probe is small. Therefore, a spectroscopic probe that can realize high spatial resolution is required.

  Accordingly, an object of the present invention is to provide a spectroscopic probe that can further increase the spatial resolution and a spectroscopic device including the spectroscopic probe.

  A spectroscopic probe according to one aspect of the present invention includes an excitation fiber that guides excitation light to a sample, and a detection fiber that receives signal light from the sample. The spectroscopic probe has a spatial resolution of 1.0 mm or less based on an analysis region in which an irradiation region of excitation light emitted from the end surface on the sample side of the excitation fiber and a light receiving region of the detection fiber overlap. The end surface of the tip portion on the sample side of at least one of the excitation fiber and the detection fiber is formed obliquely with respect to the fiber axis, and the excitation fiber and the detection optical fiber are arranged.

  In the above configuration, the end surface of the distal end portion of at least one of the excitation fiber and the detection fiber is disposed obliquely with respect to the fiber axis so that the spatial resolution based on the analysis region is 1.0 mm or less. In addition, an excitation fiber and a detection optical fiber are arranged. Therefore, the spectral probe having the above configuration can realize a high spatial resolution of 1.0 mm or less.

  In one embodiment, the end surface formed obliquely with respect to the fiber axis may be mirror-coated.

  In this case, the excitation light is reflected by the mirror-coated end face, and the optical path of the excitation light is emitted strongly from the excitation fiber and / or the signal light is reflected by the mirror-coated end face, and the optical path of the signal light is The light is bent and incident on the detection fiber.

  In one embodiment, the end surface formed obliquely with respect to the fiber axis may be a polished surface.

  In this case, by polishing the end face of the optical fiber whose end face is orthogonal to the fiber axis, an excitation fiber and / or a detection fiber having an end face formed obliquely with respect to the fiber axis can be easily obtained. Can be manufactured.

  In one embodiment, an end surface formed obliquely with respect to the fiber axis may be processed with a lens.

  In this case, the analysis region can be made narrower by the lens effect due to the end face.

  In one embodiment, the distance between the sample-side tips of the excitation probe and the detection probe may be not more than three times the diameter of the smaller diameter fiber of the excitation fiber and the detection fiber.

  Thereby, it is easy to realize higher spatial resolution.

  In one embodiment, the excitation fiber and the detection fiber have a fixed region fixed to each other on the tip side on the sample side, and in the fixed region, the fiber axis of the excitation fiber and the fiber axis of the detection fiber May be parallel.

  In this case, since at least one end face of the excitation fiber and the detection fiber is inclined with respect to the fiber axis, at least one of the irradiation region and the light reception region is a fiber axis of both the excitation fiber and the detection fiber. Will be inclined with respect to. As a result, the analysis area is more reliably reduced.

  A spectroscopic device according to another aspect of the present invention includes the spectroscopic probe, a light source unit that outputs excitation light supplied to the excitation fiber included in the spectroscopic probe, and the detection fiber included in the spectroscopic probe. A spectroscope for spectrally separating the signal light.

  In the spectroscopic device having the above-described configuration, the spatial resolution by the spectroscopic probe can be set to 1.0 mm or less, so that spectroscopic analysis of a smaller sample can be performed.

  ADVANTAGE OF THE INVENTION According to this invention, the spectroscopic probe which can make spatial resolution higher, and a spectroscopic device provided with the same can be provided.

It is drawing which shows typically the structure of the spectrometer concerning one Embodiment. (A) is an enlarged view of the front-end | tip part by the side of the sample of the spectroscopy probe shown in FIG. (B) is a schematic diagram of an analysis region when viewed from the direction of arrow α in (a). (A) is a schematic diagram of an experimental configuration example in the case of performing spectral analysis of an electrolyte solution of a lithium ion secondary battery with a spectroscopic probe. (B) is sectional drawing along the IIIb-IIIb line | wire of (a). It is a schematic diagram which shows the 1st modification of the spectroscopy probe shown to Fig.2 (a). It is a schematic diagram which shows the 2nd modification of the spectroscopy probe shown to Fig.2 (a). It is drawing which shows the 3rd modification of the spectroscopy probe shown to Fig.2 (a). It is drawing which shows the 4th modification of the spectroscopy probe shown to Fig.2 (a). It is drawing which shows the 5th modification of the spectroscopy probe shown to Fig.2 (a).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same reference numerals are given to the same elements, and duplicate descriptions are omitted. The dimensional ratios in the drawings do not necessarily match those described. In the description, words indicating directions such as “up” and “down” are convenient words based on the state shown in the drawings.

  FIG. 1 is a drawing schematically showing a configuration of a spectroscopic device according to an embodiment. The spectroscopic device 1 is a so-called Raman spectroscopic device. The spectroscopic device 1 includes an excitation light source (light source unit) 2, a spectroscopic probe 10 as a Raman probe, and a spectroscope 3. In FIG. 1, a state in which the sample 20 is measured by the spectroscopic device 1 is schematically shown. In FIG. 1, the sample 20 is a liquid sample, and an example of the sample 20 is an electrolyte solution of a lithium ion secondary battery, as will be described later.

  The excitation light source 2 may be a light source that can output excitation light having a predetermined wavelength that allows Raman spectroscopy. An example of the excitation light source 2 is a laser light source. A specific example of the excitation light source 2 as a laser light source is a solid-state laser that outputs light having a wavelength of 532 nm as excitation light.

  The spectroscopic probe 10 propagates the excitation light 11 output from the excitation light source 2 to the sample 20 and the signal light as Raman scattered light from the sample 20 irradiated with the excitation light to the spectrometer 3. And a detection fiber 15.

  The spectroscope 3 is a device for splitting Raman scattered light output from the detection fiber 15. The spectroscope 3 only needs to be able to split Raman scattered light, and a known spectroscope 3 can be used.

  In one embodiment, as shown in FIG. 1, the spectroscopic device 1 is a first for causing the excitation light output from the excitation light source 2 to enter the incident end 11 b (end on the excitation light source 2 side) of the excitation fiber 11. The optical system (incident side optical system) 4 may be provided. In the present embodiment, the excitation light source 2 itself is described as the light source unit. However, the light source unit may include the first optical system 4 together with the excitation light source 2.

  Similarly, the spectroscopic device 1 includes a second optical system (exit-side optical system) for causing the signal light output from the output end (end on the spectroscope 3 side) 15 b of the detection fiber 15 to enter the spectroscope 3. 5 may be provided. Furthermore, the spectroscopic device 1 may include a filter that cuts the excitation light and allows only the signal light to pass through on the optical path of the signal light guided to the spectroscope 3 from the emission end 15b. By providing such a filter, the detection sensitivity is improved.

  The configuration of the spectroscopic probe 10 will be described in more detail with reference to FIGS. 2 (a) and 2 (b). FIG. 2A is an enlarged view of the tip portion on the sample side of the spectroscopic probe shown in FIG. FIG. 2A schematically shows the tip of the spectroscopic probe 10. FIG. 2B is a schematic diagram of the analysis region when viewed from the direction of the arrow α in FIG.

  The spectroscopic probe 10 may have a fixed region F in which the excitation fiber 11 and the detection fiber 15 are fixed to each other at the distal end portion on the sample 20 side. In the fixed region F, the fiber axis C1 of the excitation fiber 11 may be substantially parallel to the fiber axis C2 of the detection fiber 15.

  The method for fixing the excitation fiber 11 in the fixed region F to the detection fiber 15 (or the detection fiber 15 to the excitation fiber 11) is a method that can fix them and can perform a desired analysis. That's fine. For example, the excitation fiber 11 and the detection fiber 15 may be fixed with an adhesive or the like, or the excitation fiber 11 and the detection fiber 15 may be fixed with a fixing member. As the member, for example, a member in which a hole into which each of the excitation fiber 11 and the detection fiber 15 can be inserted is formed.

  In the fixed region F, an example of the distance between the excitation fiber 11 and the detection fiber 15 is not more than three times the diameter of the smaller diameter of the excitation fiber 11 and the detection fiber 15. Thereby, the spatial resolution of the spectroscopic probe 10 to be described later can be further increased. The distance between the excitation fiber 11 and the detection fiber 15 is, for example, the fiber axis (or central axis or optical axis) C1 of the excitation fiber 11 and the fiber axis (or central axis or optical axis) of the detection fiber 15. ) Distance to C2.

  The excitation fiber 11 is an optical fiber having a core portion 12 and a cladding portion 13. The refractive index of the core part 12 is 1.5-1.8, for example. The clad part 13 is smaller than the refractive index of the core part 12 and is, for example, 1.4 to 1.7. In one embodiment, the excitation fiber 11 may have a diameter that can be inserted into the sample 20. An example of the diameter of the excitation fiber 11 is 30 μm. In the case of the excitation fiber 11 having a diameter of 30 μm, an example of the thickness of the clad portion 13 is 1.75 μm. The end surface 11a at the tip of the excitation fiber 11 on the sample 20 side is inclined with respect to the fiber axis C1. An example of the inclination angle θ1 of the end face 11a with respect to the fiber axis C1 is 45 °. The end surface 11a may be a flat surface as shown in FIG. A mirror coat is applied to the end face 11a. The mirror coating can be realized, for example, by forming the metal film 14 on the outer surface of the end surface 11a. Specific examples of the mirror coat include aluminum plating and silver plating.

  In the above configuration, the excitation light propagating through the excitation fiber 11 is reflected by the end face 11 a and irradiated to the side of the excitation fiber 11. An area irradiated with the excitation light emitted from the excitation fiber 11 is referred to as an irradiation area 30. 2A and 2B, the irradiation region 30 is shown by hatching.

  The excitation fiber 11 can be manufactured as follows. First, a polished surface is formed by polishing an end face of the optical fiber orthogonal to the fiber axis C1 so as to be inclined with respect to the fiber axis C1. Next, a mirror coat is applied to the polished surface. The mirror coating can be performed, for example, by forming the metal film 14 by vapor deposition.

  Similar to the excitation fiber 11, the detection fiber 15 is an optical fiber having a core portion 16 and a cladding portion 17. The example of the refractive index of the core part 16 and the clad part 17 is the same as that of the excitation fiber 11. In one embodiment, as in the case of the excitation fiber 11, the diameter of the detection fiber 15 may be a size that can be inserted into the sample 20. Examples of the diameter of the detection fiber 15 and the thickness of the cladding portion 17 may be the same as the diameter of the excitation fiber 11 and the thickness of the cladding portion. An end face 15a on the distal end side of the detection fiber 15 is orthogonal to the fiber axis C2.

  The detection fiber 15 is arranged on the side from which the excitation light reflected by the end face 11a of the excitation fiber 11 is emitted. The detection fiber 15 is placed on the excitation fiber 11 so that Raman scattered light (signal light) generated from the sample 20 irradiated with the excitation light from the end surface 11a of the excitation fiber 11 is incident from the end surface 15a. Is arranged. For example, as shown in FIG. 2, the detection fiber 15 is excited so that the excitation fiber 11 protrudes from the detection fiber 15, that is, a step is generated at the tip of the spectroscopic probe 10 on the sample 20 side. The optical fiber 11 is disposed.

  In one embodiment, as shown in FIG. 2, the detection fiber 15 is disposed outside the irradiation region 30 of the excitation light emitted from the excitation fiber 11. In this case, it is preferable from the viewpoint of improving the spatial resolution that the distance between the end face 15a and the irradiation region 30 is narrow. In one embodiment, on the end face 11a of the excitation fiber 11, the edge opposite to the detection fiber 15 side, that is, the edge located on the incident end 11b (see FIG. 1) side in the fiber axis C1 direction of the end face 11a. It may be arranged so that the end face 15a is located at the same position or in the vicinity thereof.

  In the above configuration, the excitation light output from the excitation light source 2 and incident on the excitation fiber 11 propagates through the excitation fiber 11. The excitation light guided toward the end surface 11a by the excitation fiber 11 is mirror-coated and reflected by the end surface 11a which is a polished surface. Since the reflection on the end surface 11a is a reflection other than the total reflection condition, the excitation light reflected on the end surface 11a passes through the cladding portion (wall surface) 13 of the excitation fiber 11 and is lateral to the excitation fiber 11. The light is emitted from the detection fiber 15 side. That is, the excitation light that has propagated through the excitation fiber 11 is emitted from the excitation fiber 11 with its optical path bent at the end face 11a. When the sample 20 is irradiated with the excitation light emitted from the excitation fiber 11, the Raman scattered light generated in the sample 20 enters the detection fiber 15 as signal light. The signal light incident on the detection fiber 15 travels through the detection fiber 15 and then exits from the exit end 15b (see FIG. 1). The signal light emitted from the emission end 15 b is incident on the spectroscope 3 and can be split in the spectroscope 3. Therefore, the sample 20 can be analyzed by the spectroscopic device 1.

  While signal light is generated from the sample 20 in the excitation light irradiation region 30, the detectable signal light is light that can enter the detection fiber 15. The light that can enter the detection fiber 15 is light in a region within the viewing angle (or the maximum incident angle of light that can be incident on the detection fiber 15) on the end face 15 a side of the detection fiber 15. In the following description, a region within the viewing angle of the detection fiber 15 is referred to as a light receiving region 31. For example, the light receiving region 31 may be defined by the numerical aperture of the detection fiber 15. In FIG. 2A and FIG. 2B, the light receiving region 31 is shown with hatching different from the irradiation region 30.

  Since the sample 20 in the irradiation region 30 is excited by the excitation light and the signal light generated from the sample 20 in the light receiving region 31 is incident on the detection fiber 15, the irradiation region 30 and the light receiving region 31 overlap. A sample 20 in the region is analyzed by the spectroscopic device 1. Therefore, in the following description, an area outside the spectroscopic probe 10 and an overlapping area of the excitation light irradiation area 30 and the light receiving area 31 of the detection fiber 15 is also referred to as an analysis area 32.

  Since the size of the analysis region 32 is a region where the sample 20 can be analyzed by Raman spectroscopy, the size of the analysis region 32 corresponds to the spatial resolution of the spectroscopic probe 10. In the present embodiment, the spatial resolution of the spectroscopic probe 10 is defined as follows.

That is, the spatial resolution of the spectroscopic probe 10 is the largest width value among the width L1, the width L2, and the width L3 (see FIGS. 2A and 2B) in the analysis region 32. Width L1, the value of the largest width of the width L2 and the width L3 is also referred to as _{L max.}

  The width L1 is a width in a direction perpendicular to the fiber axis C2 of the detection fiber 15 on a plane including the fiber axes C1 and C2 of the excitation fiber 11 and the detection fiber 15 as shown in FIG. . The width L2 is the width of the analysis region 32 in the direction orthogonal to the plane including the fiber axes C1 and C2 of the excitation fiber 11 and the detection fiber 15 as shown in FIG. The width L3 is the width of the analysis region 32 in a direction parallel to the fiber axes C1 and C2. In the following description, L1, L2, and L3 may be used to indicate corresponding width directions.

Unless otherwise specified in this specification, the spatial resolution of the spectroscopic device 1 is the spatial resolution defined above. In this specification, high spatial resolution means that L _max corresponding to the spatial resolution is small.

  As described above, the excitation light that has propagated through the excitation fiber 11 is emitted from the excitation fiber 11 with its optical path bent at the end face 11a. That is, the irradiation region 30 extends toward the sample 20 with reference to the end face 11a. Therefore, for the sake of explanation, the direction in which the light propagating along the fiber axis C1 extends in the traveling direction of the light reflected by the end face 11a will be referred to as the extending direction A1 of the irradiation region 30. This extending direction corresponds to the optical path of the excitation light reflected by the end face 11a. In FIG. 2, in order to show the relationship between the extending direction A1 and the fiber axis C1, an arrow indicating the extending direction A1 is extended to the end face 11a. This is the same in other figures.

  Similarly, since the light receiving region 31 is a region of light that can enter the detection fiber 15, it extends to the side opposite to the end face 15a. The light receiving region 31 corresponds to an irradiation region of light when the light propagating along the fiber axis C2 is emitted from the end face 15a. Therefore, the light traveling direction when the light propagating in the detection fiber 15 along the fiber axis C2 is emitted from the end face 15a is referred to as an extending direction A2 of the light receiving region 31. This extending direction A2 corresponds to the optical path of signal light that can be incident on the detection fiber 15. As shown in FIG. 2, in the form in which the end face 15a is orthogonal to the fiber axis C2, the extending direction of the light receiving region 31 is the same as the direction of the fiber axis C2.

In the spectroscopic probe 10, the end surface 11 a is inclined with respect to the fiber axis C <b> 1, so that the excitation light propagating through the excitation fiber 11 is bent at the end surface 11 a to the side of the excitation fiber 11. Emitted. Therefore, the extending direction A1 of the irradiation region 30 intersects the fiber axis C1 at a certain angle (about 90 ° in the example of FIG. 2A). Since the fiber axis C2 is substantially parallel to the fiber axis C1 and the extending direction A2 is the same as the direction of the fiber axis C2, the extending direction A1 of the irradiation region 30 and the extending direction A2 of the light receiving region 31 are the same. Intersect. Therefore, the analysis region 32 is smaller than when the end surface 11a is orthogonal to the fiber axis C1, that is, when the extending direction A1 and the extending direction A2 are substantially parallel. Therefore, the spectroscopic probe 10 can realize a high resolution of 1.0 mm or less as a spatial resolution, that is, L _max of 1.0 mm or less.

The spatial resolution is determined by the largest value L _max among L1, L2, and L3. Therefore, the widths L1, L2, and L3 may be 1.0 mm or less.

  However, L1 is preferably 100 μm or less, and more preferably 50 μm or less. L2 is preferably 50 μm or less, and more preferably 30 μm or less. L3 is preferably 100 μm or less, and more preferably 50 μm or less.

  According to the preferable range as described above, for example, the spectroscopic analysis of the smaller sample 20 is possible in the directions of the widths L1, L2, and L3.

  The range examples of L1, L2, and L3 as exemplified above are obtained by adjusting the arrangement relationship between the excitation fiber 11 and the detection fiber 15, and the shape of the end surface 11a and the inclination angle θ1 of the end surface 11a with respect to the fiber axis C1. Can be realized.

  For example, if the width L2 is 50 μm or less, it is possible to perform spectroscopic analysis using the electrolyte solution of the lithium ion secondary battery as the sample 20. This point will be described with reference to FIGS. 3 (a) and 3 (b).

  Fig.3 (a) is a schematic diagram of the example of an experiment structure in the case of carrying out the spectral analysis of the electrolyte solution of a lithium ion secondary battery with a spectroscopic probe. FIG. 3B is a cross-sectional view taken along line IIIb-IIIb in FIG. FIG. 3B shows an enlarged part of the cross-sectional configuration along the line IIIb-IIIb.

  A sample 20 shown in FIG. 3A is an electrolytic solution of a lithium ion secondary battery. The refractive index of the electrolytic solution is usually 1.3 to 1.6. A lithium ion secondary battery as an experimental model has a positive electrode plate 21 and a negative electrode plate 22 that are spaced apart from each other. The positive electrode plate 21 is obtained by applying a paste of positive electrode active material powder onto an aluminum foil 25. The negative electrode plate 22 is obtained by applying a paste of negative electrode active material powder on a copper foil 26. An electrolyte solution as the sample 20 is injected between the positive electrode plate 21 and the negative electrode plate 22. Separators 23 and 24 are provided on the inner surface of the positive electrode plate 21 (surface on the negative electrode plate 22 side) and the inner surface of the negative electrode plate 22 (surface on the positive electrode plate 21 side), respectively. The components such as the positive electrode plate 21 and the negative electrode plate 22 are accommodated in the case so that the electrolyte does not leak, but the description of the case is omitted in FIGS. 3 (a) and 3 (b).

  With respect to the experimental model, as shown in FIG. 3B, the spectroscopic probe 10 has a positive electrode plate 21 (or a negative electrode) whose direction perpendicular to the plane including the fiber axes C1 and C2 (ie, the direction of the width L2). It arrange | positions between a pair of separators 23 and 24 so that it may become the plate | board thickness direction of the board 22).

  In the actual battery, the interval between the positive electrode plate and the negative electrode plate is usually 10 μm to 50 μm. Between the positive electrode plate and the negative electrode plate, a separator infiltrated with an electrolytic solution having the same thickness as that of the gap (that is, 10 μm to 50 μm) is sandwiched.

  Since the space for inserting the spectroscopic probe 10 is not secured in such a configuration of the actual battery, the experimental model shown in FIG. 3A uses two separators 23 and 24 in order to use the electrolytic solution as the sample 20. A configuration is adopted in which the spectroscopic probe 10 can be inserted into the electrolytic solution therebetween while being spaced apart.

  If the width L2 of the analysis region 32 is 50 μm or less, the spacing between the separators 23 and 24 can be reduced by the arrangement of the spectroscopic probe 10 as shown in FIGS. 3A and 3B. It is possible to analyze the electrolyte with a model closer to the configuration of Further, if the width L2 is 30 μm or less, for example, the thickness of the separators 23 and 24 is set to 20 μm, and the distance between the separators 23 and 24 is set to 30 μm, so that the gap between the positive electrode plate 21 and the negative electrode plate 22 is increased. The interval is 70 μm, and the configuration is closer to that of a real battery. With such an experimental model, it is possible to analyze a phenomenon in an actual battery, which has not been conventionally known, using the spectroscopic probe 10.

The configuration in which the spatial resolution of the spectroscopic probe 10 is 1.0 mm or less and the width L2 is 50 μm or less, more preferably 30 μm or less may satisfy the following conditions, for example.
(A) The excitation fiber 11 and the detection fiber 15 having a diameter of 30 μm to 50 μm are fixed in the fixed region F.
(B) In the fixed region F, the distance between the excitation fiber 11 and the detection fiber 15 is not more than three times the diameter of the smaller one of these fibers, preferably fixed so as to contact each other. .
(C) In the fixed region F, the fiber axis C1 and the fiber axis C2 are substantially parallel.
(D) The end surface 11a as a flat surface is inclined at 30 ° to 60 ° with respect to the fiber axis C1. An example of the inclination angle θ1 is 45 °.
(E) The end face 15 a of the detection fiber 15 is disposed so as to be close to the irradiation region 30.

  Here, the experimental model of the lithium ion secondary battery has been described as an example. However, for example, when the length of the sample 20 to be analyzed is short in the width L2 direction, the same configuration can be adopted.

  Since the optical fiber that propagates the pumping light (pumping fiber 11) and the optical fiber that receives the signal light (detecting fiber 15) are different, for example, the propagation of the pumping light and the propagation of the signal light can be performed with one optical fiber. The detection sensitivity is improved as compared with the case where two functions are provided. This is because Raman scattering or light emission of the optical fiber itself can be removed.

  In the spectroscopic probe 10, in the fixed region F on the sample 20 side, if the excitation fiber 11, the detection fiber 15, and their fiber axes C1 and C2 are substantially parallel, the tip of the spectroscopic probe 10 is made smaller. be able to. Therefore, even if the sample 20 is small, the tip portion of the spectroscopic probe 10 can be disposed in the sample 20 or in the vicinity of the sample 20, so that the smaller sample 20 can be spectroscopically analyzed while maintaining high spatial resolution. From the viewpoint of reducing the fixed region F and realizing higher spatial resolution, it is preferable that the excitation fiber 11 and the detection fiber 15 are in contact with each other, but as described above, the excitation fiber 11 and the detection fiber The distance between them may be no more than three times the diameter of the smaller of these fibers.

  Furthermore, since the end surface 11a itself is processed (obliquely polished) and the optical path of the excitation light is bent, the spatial resolution is improved as compared with, for example, a case where a minute lens is formed to collect light. Easy.

  Since the end surface 11a is a polished surface, it is easier to adjust the optical path of the excitation light than when there are irregularities in the end surface 11a. Further, after polishing the end face of the optical fiber, the excitation fiber 11 can be easily manufactured by applying a mirror coat.

  While various forms of the spectroscopic probe 10 have been described above, the form of the spectroscopic probe 10 can be variously modified as long as the spatial resolution based on the analysis region 32 is 1.0 mm or less. Hereinafter, various modified examples of the spectroscopic probe will be described focusing on differences from the spectroscopic probe 10. Various types of spectroscopic probes described below can be applied to the spectroscopic device 1 instead of the spectroscopic probe 10. In addition, the spectral probes of the following modifications have at least the same functions and effects as the spectral probe 10. In the drawings showing the respective modifications, the drawing of the state viewed from the direction of the arrow α indicated by the two-dot chain line in FIG. 2A is omitted, but the definition of the spatial resolution in each modification is defined by the spectroscopic probe 10. It is the same as the case of.

  FIG. 4 is a schematic diagram showing a first modification of the spectroscopic probe shown in FIG. In FIG. 4, the distal end portion on the sample 20 side of the spectroscopic probe 40 as the first modification is shown in an enlarged manner. The spectroscopic probe 40 includes an excitation fiber 41 and a detection fiber 15. The spectroscopic probe 40 is different from the spectroscopic probe 10 in that an excitation fiber 41 is provided instead of the excitation fiber 11.

  The excitation fiber 41 is an optical fiber having a core portion 12 and a clad portion 13 like the excitation fiber 11. The excitation fiber 41 is different from the excitation fiber 11 in that the end surface 41a of the sample 20 is a lens-processed surface, that is, a curved surface. More specifically, the end surface 41a is a curved surface that is convex outward. As in the case of the excitation fiber 11, a mirror coat is applied to the end face 41 a, and an example of the mirror coat is a metal film 14.

  The shape of the lens-processed end surface 41a is such that a spatial resolution of 1.0 mm or less can be obtained, and it may be set so that the inside of the sample 20 can be analyzed. For example, when the electrolyte solution of the lithium ion secondary battery shown in FIG. 3 is used as the sample 20, the shape of the lens-processed end surface 41a may be a shape that can further obtain the preferable range exemplified by the width L2. Further preferred.

  Since the end surface 41a is inclined with respect to the fiber axis C1 of the excitation fiber 41 and the end surface 41a is mirror-coated, the analysis region 32, which is the overlapping region of the irradiation region 30 and the light receiving region 31, is separated into the spectroscopic region. Similar to the case of the probe 10, it becomes smaller. As a result, the spectral probe 40 can also realize a spatial resolution of 1.0 mm or less.

  FIG. 5 is a schematic diagram showing a second modification of the spectroscopic probe shown in FIG. FIG. 5 shows an enlarged tip of the spectroscopic probe 50 of the second modification on the sample 20 side. The spectroscopic probe 50 shown in FIG. 5 includes an excitation fiber 51 and a detection fiber 52.

  The excitation fiber 51 is an optical fiber having a core portion 12 and a clad portion 13 like the excitation fiber 11. The excitation fiber 51 is different from the excitation fiber 11 in that the end surface 51a on the sample 20 side is not mirror-coated.

  Similar to the detection fiber 15, the detection fiber 52 is an optical fiber having a core portion 16 and a cladding portion 17. The detection fiber 52 is different from the detection fiber 15 in that the end surface 52a on the sample 20 side is inclined with respect to the fiber axis C2.

  Since the end surface 51 a of the excitation fiber 51 is not mirror-coated, the excitation light guided to the excitation fiber 51 is emitted from the excitation fiber 51 through the end surface 51 a. When passing through the end face 51a, the excitation light is refracted by the end face 51a. Since the end face 51a is inclined with respect to the fiber axis C1, the refracted excitation light is emitted in an oblique direction with respect to the fiber axis C1. Therefore, the extending direction A1 of the irradiation region 30 is inclined with respect to the fiber axis C1. At this time, the end surface 51a is formed such that the extending direction A1 of the irradiation region 30 is bent toward the detection fiber 52 with respect to the fiber axis C1.

  The end face 52 a of the detection fiber 52 is formed by polishing the end face of the optical fiber, as in the case of the excitation fiber 11. That is, the end surface 52a is a polished surface like the end surface 51a (or the end surface 11). The light is refracted at the end face 52 a and enters the detection fiber 52. The optical path of the light incident on the detection fiber 52 is an optical path opposite to the optical path when the light propagating through the detection fiber 52 is emitted from the end face 52a. Therefore, the extending direction A2 of the light receiving region 31 is inclined with respect to the fiber axis C2. At this time, the end face 52a is formed such that the extending direction A2 of the light receiving region 31 is bent toward the excitation fiber 51 with respect to the fiber axis C2.

  Similarly to the case shown in FIG. 2A, the excitation fiber 51 and the detection fiber 52 are arranged so that they are in contact with each other in the fixed region F and the fiber axes C1 and C2 are substantially parallel to each other. Yes. However, in one embodiment, unlike the case shown in FIG. 2A, the edge on the more distal side of the end face 51 a of the excitation fiber 51 and the edge on the more distal side of the end face 52 a of the detection fiber 52. It arrange | positions so that an edge may overlap.

  In one embodiment, as illustrated in FIG. 5, in the spectroscopic probe 50, the excitation fiber 51 and the detection fiber 52 may have a target configuration with respect to a plane including their contact portions.

  When the end face 51a is not inclined with respect to the fiber axis C1, the extending direction A1 of the irradiation region 30 is the same direction as the fiber axis C1 of the excitation fiber 51, and the excitation light emitted from the end face 51a is the end face 51a. It spreads as you move away from it. Similarly, when the end face 52a is not inclined with respect to the fiber axis C2, the extending direction A2 of the light receiving region 31 is the same as the fiber axis C2 of the detection fiber 52. As described above, the optical path of the light incident on the detection fiber 52 is an optical path opposite to the optical path where the light propagating through the detection fiber 52 is emitted from the end face 52a. Therefore, the shape of the light receiving region 31 is a shape in which the opposite side to the end face 52 a is widened like the irradiation region 30. Since the fiber axis C1 and the fiber axis C2 are substantially parallel, when the end faces 51a and 52a are not inclined, the extending direction A1 of the irradiation region 30 and the extending direction A2 of the light receiving region 31 are substantially the same. Parallel to Therefore, the irradiation region 30 and the light receiving region 31 almost entirely overlap on the side opposite to the end surface 51a (or end surface 52a) side.

  On the other hand, if the end faces 51a and 52a are inclined with respect to the corresponding fiber axes C1 and C2, respectively, the extending direction A1 of the irradiation region 30 and the extension of the light receiving region 31 are shown in FIG. It intersects with the current direction A2. Therefore, the analysis region 32, which is a region where the irradiation region 30 and the light receiving region 31 intersect, is smaller than when the extending direction A1 and the extending direction A2 are substantially parallel. As a result, the spectroscopic device 1 can obtain a high spatial resolution of 1.0 mm or less.

The positional relationship between the inclination angle θ1 of the end surface 51a with respect to the fiber axis C1, the inclination angle θ2 of the end surface 52a with respect to the fiber axis C2, and the arrangement of the excitation fiber 51 and the detection fiber 52 is 1.0 mm or less in spatial resolution (ie, L _max ). Therefore, it is only necessary to set so that the inside of the sample 20 can be analyzed. For example, when the electrolyte solution of the lithium ion secondary battery shown in FIGS. 3A and 3B is used as the sample 20, the width L2 is preferably 50 μm or less, more preferably 30 μm or less. In addition, the inclination angle θ1 of the end face 51a with respect to the fiber axis C1, the inclination angle θ2 of the end face 52a with respect to the fiber axis C2, and the arrangement relationship between the excitation fiber 51 and the detection fiber 52 are set. When the end face 51a is not mirror-coated, the inclination angle θ1 can be determined in consideration of the relationship between the refractive index of the sample 20 and the refractive index of the core portion 12. Similarly, the inclination angle θ2 can be determined in consideration of the relationship between the refractive index of the sample 20 and the refractive index of the core portion 12.

  In FIG. 5, the end edge 51 a of the excitation fiber 51 is arranged so that the edge on the more distal side overlaps the position of the edge on the more distal side of the end face 52 a of the detection fiber 52. The edge of the end surface 51a and the edge of the end surface 52a of the detection fiber 52 may be shifted.

  FIG. 6 is a drawing showing a third modification of the spectroscopic probe shown in FIG. In FIG. 6, the tip part on the sample 20 side of the spectroscopic probe 60 of the third modified example is shown in an enlarged manner. The spectroscopic probe 60 shown in FIG. 6 includes an excitation fiber 61 and a detection fiber 62.

  The excitation fiber 61 is an optical fiber having a core portion 12 and a cladding portion 13, similarly to the excitation fiber 11. The excitation fiber 61 is different from the excitation fiber 11 in that the end surface 61a on the sample 20 side is not mirror-coated and the end surface 61a is lens-processed, that is, the end surface 61a is a curved surface. Is different. In other words, the excitation fiber 61 corresponds to a form in which the end surface 41a of the excitation fiber 41 shown in FIG. 4 is not mirror-coated.

  Like the detection fiber 15, the detection fiber 62 is an optical fiber having a core portion 16 and a cladding portion 17. The detection fiber 62 is different from the detection fiber 15 in that the end surface 62a on the sample 20 side is subjected to lens processing, that is, the end surface 62a is a curved surface. In this configuration, the end face 62a is inclined with respect to the fiber axis C2.

  The difference between the excitation fiber 51 and the detection fiber 52 and the excitation fiber 61 and the detection fiber 62 included in the spectroscopic probe 50 shown in FIG. 5 will be described. The excitation fiber 61 and the detection fiber 62 are end surfaces. It differs from the excitation fiber 51 and the detection fiber 52 in that the lens 61a and the end face 62a are processed.

  The end surface 61a is curved so that the extending direction A1 of the irradiation region 30 is bent toward the detection fiber 62 with respect to the fiber axis C1. The end surface 62a is curved so that the extending direction A2 of the light receiving region 31 is bent toward the excitation fiber 61 with respect to the fiber axis C2.

Since the end surface 61a is lens-processed, the excitation light can converge after being emitted from the end surface 61a due to the lens effect of the end surface 61a. On the other hand, since the end surface 62a of the detection fiber 62 is lens-processed, the light that has propagated through the detection fiber 62 toward the end surface 62a is emitted so as to converge at the end surface 62a. The light can enter the detection fiber 62 through the opposite optical path. Therefore, as shown in FIG. 6, the light once converged outside the end face 62a is incident on the end face 62a. Therefore, both the irradiation region 30 and the light receiving region 31 have a converging portion outside the end faces 61a and 62a, and intersect the extending direction A1 of the irradiation region 30 and the extending direction A2 of the light receiving region 31. As a result, the analysis region 32, which is a region where the irradiation region 30 and the light receiving region 31 overlap, can be made narrower. That is, the spatial resolution (that is, L _max ) of the spectroscopic device 1 can be set to 1.0 mm or less.

  The shape of the end surface 61a, the shape of the end surface 62a, and the arrangement relationship between the excitation fiber 61 and the detection fiber 62 may be set so that the spatial resolution is 1.0 mm or less and the inside of the sample 20 can be analyzed. The point is the same as in the case of the spectroscopic probe 10 and other modified examples.

  Further, the spectroscopic probe may have a form in which the functions of the excitation fiber and the detection fiber included in the various types of spectroscopic probes 10, 40, 50, and 60 described above are reversed, or various forms of the spectroscopic probe 10 may be used. , 40, 50, 60 may be a spectroscopic probe in which excitation fibers and detection fibers are combined. These points will be specifically described with reference to a fourth modification and a fifth modification.

  FIG. 7 is a drawing showing a fourth modification of the spectroscopic probe shown in FIG. In FIG. 7, the tip part on the sample 20 side of the spectroscopic probe 70 of the fourth modified example is shown in an enlarged manner. In FIG. 7, an arrow indicating the extending direction A2 of the light receiving region 32 is extended to an end face 72a described later in order to show the relationship with the fiber axis C2. The spectroscopic probe 70 shown in FIG. 7 includes an excitation fiber 71 and a detection fiber 72.

  The excitation fiber 71 is an optical fiber having a core portion 12 and a cladding portion 13 as in the case of the excitation fiber 11. The excitation fiber 71 is different from the excitation fiber 11 in that the end surface 71a on the sample 20 side is orthogonal to the fiber axis C1.

  The detection fiber 72 is an optical fiber having a core portion 16 and a cladding portion 17 as in the case of the detection fiber 15. The detection fiber 72 is different from the detection fiber 15 in that the end surface 72a on the sample 20 side is a flat surface inclined with respect to the fiber axis C2, and the end surface 72a is mirror-coated. For example, the end face 72a is mirror-coated by forming the metal film 14 on the end face 72a.

The positional relationship between the excitation fiber 71 and the detection fiber 72 and the inclination angle θ2 of the end face 72a with respect to the fiber axis C2 has a spatial resolution (ie, L _max ) of 1.0 mm or less, and the sample 20 to be analyzed is analyzed. It only has to be set as possible.

  The configuration of the spectroscopic probe 70 shown in FIG. 7 uses the detection fiber 15 shown in FIG. 2A as the excitation fiber 71, and the excitation fiber 11 shown in FIG. 2A is used as the detection fiber 72. It corresponds to the form when used as. In this case, the irradiation region 30 and the light receiving region 31 in the spectroscopic probe 70 are reversed from those in the spectroscopic probe 10, but the analysis region 32, which is an overlapping region thereof, is the same as in the spectroscopic probe 10. It can be. Therefore, the spectral probe 70 can also realize a high spatial resolution of 1.0 mm or less.

  FIG. 8 is a drawing showing a fifth modification of the spectroscopic probe shown in FIG. FIG. 8 is an enlarged view of the tip portion on the sample 20 side of the spectroscopic probe 80 of the fifth modification. A spectroscopic probe 80 shown in FIG. 8 is a spectroscopic probe including the excitation fiber 51 shown in FIG. 5 and the detection fiber 62 shown in FIG. The tilt angle θ1 of the end surface 51a of the excitation fiber 51 with respect to the fiber axis C1, the lens processing state of the end surface 62a of the detection fiber 62, that is, the curved state of the end surface 62a and the arrangement state of the excitation fiber 51 and detection fiber 62 are It is only necessary that the spatial resolution is 1.0 mm or less and that the analysis target sample is within a range that can be analyzed.

  Heretofore, various embodiments and modifications of the present invention have been described. However, the present invention is not limited to the various embodiments and modifications described above, and various modifications can be made without departing from the spirit of the present invention. In other words, the light is reflected or refracted at the end face which is at least one of the excitation fiber and the detection fiber and is inclined with respect to the fiber axis of the fiber including the end face. As a result, the optical path of the light is changed. If the spatial resolution based on the spectroscopic analysis region is 1.0 mm or less by bending, the configuration of the spectroscopic probe can be variously modified.

  The spectroscopic probe only needs to include at least one excitation fiber and at least one detection fiber. For example, a plurality of detection fibers may be arranged around one excitation fiber. In this case, the plurality of detection fibers may be arranged so that the plurality of light receiving regions overlap with different portions of the irradiation region. Alternatively, a plurality of excitation fibers may be arranged around one detection fiber. Alternatively, a plurality of pairs of excitation fibers and detection fibers may be provided.

  In the modified examples of the various spectroscopic probes, the excitation fiber and the detection fiber are fixed so that they are in contact with each other in the fixed region. However, the desired spatial resolution of 1.0 mm or less can be obtained. If present, the excitation fiber and the detection fiber may be separated from each other. As illustrated, the distance between the excitation fiber and the detection fiber is preferably not more than three times the smaller of the diameters from the viewpoint of obtaining a desired spatial resolution of 1.0 mm or less.

  As long as a spatial resolution of 1.0 mm or less can be realized, in the fixed region F, the fiber axis of the excitation fiber and the fiber axis of the detection fiber may not be substantially parallel. In this case, for example, the spatial resolution is perpendicular to the fiber axis of the detection fiber in the plane including the width in the direction parallel to the fiber axis of the detection fiber in the analysis region and the fiber axis of the excitation fiber and the fiber axis of the detection fiber. The width in the right direction, or the largest value of the widths in the direction perpendicular to these two directions.

  In the description so far, in the configuration capable of realizing 1.0 mm or less as the spatial resolution, the case where the width L2 is in a more preferable range is illustrated as a more preferable form. However, the width L1 and / or the width L3 may be in a more preferable range depending on the size of the sample 20 or the like.

  Although the electrolyte solution of the lithium ion secondary battery was illustrated as a sample, a sample is not limited to this, Another liquid sample may be sufficient and gas may be a sample. For example, the sample may be blood in a living body. If a spectroscopic probe is loaded into an injection needle and its tip is introduced into a blood vessel, blood analysis can be performed without damaging human tissue. As such a medical purpose, for example, a body fluid in a living body may be spectroscopically analyzed in combination with an endoscope or the like.

  Although at least one end face of the excitation fiber and the detection fiber has been described as a polished polished face, the end face inclined with respect to the fiber axis may be a face formed by melting, for example.

  The spectroscopic device using the spectroscopic probe is not limited to the Raman spectroscopic device, and may be applied to other spectroscopic methods, for example, spectroscopic methods using fluorescence.

  DESCRIPTION OF SYMBOLS 1 ... Spectroscope, 2 ... Excitation light source (light source part), 3 ... Spectroscope, 10, 40, 50, 60, 70, 80 ... Spectral probe, 11, 41, 51, 61, 71, 81 ... Excitation fiber, 11a, 41a, 51a, 61a, 71a, 81a ... end face, 14 ... metal film (mirror coat), 15, 42, 52, 62, 72, 82 ... detection fiber, 15a, 42a, 52a, 62a, 72a, 82a ... end face, 20 ... sample, 31 ... light receiving region, 32 ... analysis region, C1 ... fiber axis (fiber axis of excitation fiber), C2 ... fiber axis (fiber axis of detection fiber), F ... fixed region.

Claims (7)

An excitation fiber for guiding the excitation light to the sample;
A detection fiber for receiving signal light from the sample;
With
The spatial resolution based on the analysis region where the irradiation region of the excitation light emitted from the end surface on the sample side of the excitation fiber and the light receiving region of the detection fiber overlap is 1.0 mm or less, The end face of the tip portion on the sample side of at least one of the excitation fiber and the detection fiber is formed obliquely with respect to the fiber axis, and the excitation fiber and the detection optical fiber are arranged. ing,
Spectroscopic probe. The end surface formed obliquely with respect to the fiber axis is mirror-coated,
The spectroscopic probe according to claim 1. The end surface formed obliquely with respect to the fiber axis is a polished surface.
The spectroscopic probe according to claim 1. The end face formed obliquely with respect to the fiber axis is lens processed,
The spectroscopic probe according to claim 1. The distance between the excitation probe and the tip of the detection probe on the sample side is not more than three times the diameter of the smaller diameter fiber of the excitation fiber and the detection fiber.
The spectroscopic probe according to any one of claims 1 to 4. The excitation fiber and the detection fiber have a fixed region fixed to each other on the tip side on the sample side, and in the fixed region, a fiber axis of the excitation fiber and a fiber axis of the detection fiber Is parallel to
The spectroscopic probe according to any one of claims 1 to 5. The spectroscopic probe according to any one of claims 1 to 6, and
A light source unit that outputs excitation light supplied to the excitation fiber of the spectroscopic probe;
A spectroscope that splits the signal light output from the detection fiber of the spectroscopic probe;
A spectroscopic device.

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