Immersion probe

Abstract

To provide an immersion probe that can prevent bubbles from accumulating in a gap even if the gap spacing filled with a liquid sample is reduced.SOLUTION: A probe comprises a sensor structure 0220 that includes a reflective mirror 0221 and a gap 0222 that is an immersion gap structural portion, and a fiber-optic tube structure 0210 that contains optical fibers 0211, 0212 for introducing light from a light source 0250 into the sensor structure 0220 and for guiding the light reflected by the reflective mirror 0221 to a light intensity measurement part 0260. A sensor structure 0224a for a short gap that is used when a measurement is conducted where the amount of light absorbed by a liquid sample is large, and the gap needs to be smaller than the normal gap where the amount of light absorbed is small can be used with a supporting column 0226 that supports the structure on the side of the reflective mirror 0221 that makes up the gap and the side that introduces light positioned at a point that is separated from a gap surface 0224b.SELECTED DRAWING: Figure 2A

Description

[Technical field]

[0001] The present invention relates to a liquid immersion probe used for measuring the light absorbance or transmittance of a liquid sample by irradiating the liquid sample with light. [Background technology]

[0002] Conventionally, an example of the above-mentioned liquid immersion probe is a probe for measuring absorbance, as described in Patent Document 1.

[0003] As shown in the cross-sectional view of Fig. 1A and the perspective view of Fig. 1B, the absorbance measurement probe 0100 described in Patent Document 1 includes a plano-convex lens 0101 and a reflecting mirror 0102 arranged opposite the plano-convex lens 0101, and a gap (liquid immersion gap structure portion) 0105 through which a liquid sample penetrates and remains or passes is formed between end faces of a cylindrical lens holder 0103 that holds the plano-convex lens 0101 and a cap-shaped mirror holder 0104 that holds the reflecting mirror 0102. In this case, the lens holder 0103 and the mirror holder 0104 are supported by a support column portion 0106, and cover glasses 0107 and 0108 are arranged on the end faces of the lens holder 0103 and the mirror holder 0104 that form the gap 0105, respectively. The cover glasses 0107, 0108 placed on the end faces of the lens holder 0103 and the mirror holder 0104 are made of colorless and transparent quartz, and their effect on measurements of absorbance, transmittance, etc. is negligible.

[0004] Here, the light intensity (irradiation intensity) before irradiating the liquid sample is I 0 The intensity of light after passing through a liquid sample with an optical path length l (the distance that light travels through the liquid sample back and forth l) is I 1 In this case, the absorbance A can be calculated by the following equation 1 (Equation 1).

[0005]

number

[0006] In this formula 1, the optical path length l corresponds to twice the distance d between the end faces of the lens holder 0103 and the mirror holder 0104 that constitute the gap 0105 of the absorbance measurement probe 0100 (hereinafter referred to as the distance d of the gap 0105). Therefore, in the absorbance measurement probe 0100, light introduced from a light source (not shown) is collected by the plano-convex lens 0101 and transmitted through the liquid in the gap 0105, and light reflected by the reflecting mirror 0102 is received through the liquid in the gap 0105 and the plano-convex lens 0101, that is, light guided from a light source (not shown) via an optical fiber is transmitted back and forth through the liquid sample in the gap 0105, whose distance d is the optical path length l / 2, and is guided to a light intensity measuring unit such as a spectrometer (not shown) via an optical fiber, thereby measuring absorbance. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2009-250825 A Summary of the Invention [Problem to be solved by the invention]

[0008] When the absorbance of a liquid sample, such as water, that has a high absorption of light, for example, far infrared rays having a wavelength of 3 micrometers or more, is measured using such a probe 0100 for measuring absorbance, I in the above formula 1 is 1 / I 0 becomes extremely small, the detection accuracy of absorbance decreases. Therefore, it is necessary to narrow the distance d of the gap 0105 between the cover glass 0106 on the lens holder 0103 side and the cover glass 0107 on the mirror holder 0104 side, which is the distance d of the gap 0105 through which the liquid sample water penetrates and remains or passes. In this absorbance measurement, if an optical path length l of, for example, 1 mm is required as the optical path length l required for the measurement, the distance d of the gap 0105 needs to be set to 0.5 mm, which is half the optical path length l.

[0009] However, in the conventional absorbance measurement probe 0100, when the distance d of the gap 0105 is reduced as described above, it becomes difficult for water, which is a liquid sample, to enter the gap 0105, and air bubbles accumulate in the gap 0105 as shown in Fig. 1C. In other words, it becomes impossible to ensure the optical path length required for measuring absorbance, and as a result, there is a problem that it is not possible to perform accurate measurement, and solving this problem has been a conventional challenge.

[0010] The present invention has been made to solve the above-mentioned problems of the conventional art, and aims to provide an immersion probe that can prevent air bubbles from accumulating in the gap even when the size of the gap through which the sample liquid penetrates and remains or passes is reduced, thereby making it possible to measure the absorptance and transmittance of the measurement light of the liquid sample with high accuracy. [Means for solving the problem]

[0011] Here, the inventors of the present invention have found that when it is necessary to reduce the size of the gap through which the sample liquid penetrates and remains or passes, reducing the area of ​​the opposing surfaces on the reflective mirror side that holds the reflective mirror that constitutes the gap and the light introducing side that introduces light from the light source makes it difficult for air bubbles to accumulate in the gap. This is believed to be because the surface tension (interfacial tension) between the opposing surfaces constituting the gap and the air bubbles attempting to remain within the gap is relatively small compared to the pressure that the gap receives from the surrounding liquid sample. As a result, by adopting a structure in which a support column portion for supporting the structure on the reflecting mirror side and the light introducing side that constitute the gap is positioned at a position spaced apart from the gap surface as a short gap sensor structure including a reflecting mirror as well as an immersion gap structure portion, that is, by ensuring a wide area around the gap in which the liquid sample can remain or pass through, it has been discovered that it is possible to prevent air bubbles from accumulating in the gap even when the gap spacing is made small.

[0012] That is, the first invention in the present invention comprises a sensor structure including a reflecting mirror and an immersion gap structure portion, and an optical fiber tube structure housing an optical fiber for introducing light from a light source into the sensor structure and guiding the light reflected by the reflecting mirror of the sensor structure to a light intensity measuring portion, and as a short gap sensor structure used when performing measurements in which a large amount of light is absorbed by the liquid in which the sensor structure is immersed and therefore the immersion gap needs to be smaller than a normal immersion gap in which the amount of absorption is small, the sensor structure can be configured so that the reflecting mirror side for forming a gap and the support column portion for supporting the structure on the light introduction side are positioned away from the gap surface.

[0013] In a second aspect of the present invention, the sensor structure is configured so as to be detachable from the optical fiber tube structure.

[0014] Furthermore, in the third aspect of the present invention, the term "large amount of absorption" refers to a relationship between light and liquid in which the absorbance is 1 / 500 or more.

[0015] Furthermore, in a fourth aspect of the present invention, the short gap refers to a gap having a gap interval of 1 mm or less and 0.3 mm or more.

[0016] Furthermore, in a fifth aspect of the present invention, the opposing area of ​​the short gap is configured to be 3.14 square millimeters (note: radius 1 mm) or more and 28.26 square millimeters (note: radius 3 mm) or less.

[0017] Furthermore, in a sixth aspect of the present invention, the liquid and the light have a relationship in which the transmittance is 10% or more and 80% or less.

[0018] Furthermore, the short gap sensor structure according to the seventh aspect of the present invention can be used for the immersion probe according to the first aspect of the present invention.

[0019] On the other hand, an absorbance measuring method according to an eighth aspect of the present invention is configured to measure the absorbance of a liquid using the liquid immersion probe according to the fourth or fifth aspect of the present invention.

[0020] A ninth aspect of the present invention provides a transmittance measuring method, which uses the immersion probe according to the fourth or fifth aspect of the present invention to measure the transmittance of a liquid.

[0021] Further, a concentration measuring method according to a tenth aspect of the present invention is configured to measure the concentration of a solution using the immersion probe according to the fourth or fifth aspect of the present invention. Effect of the Invention

[0022] According to the present invention, even if the gap through which the sample liquid penetrates and remains or passes is made small, it is possible to prevent air bubbles from accumulating in the gap, resulting in the extremely advantageous effect of making it possible to measure the absorbance and transmittance of the liquid sample with high accuracy. [Brief description of the drawings]

[0023] [Figure 1A] Cross-section of a conventional immersion probe [Figure 1B] A perspective view of the immersion probe in FIG. 1A. [Figure 1C] Cross-section of the immersion probe in Figure 1A with an air bubble trapped in the gap [Figure 2A] FIG. 1 is a cross-sectional view of an immersion probe according to a first embodiment of the present invention. [Figure 2B] A perspective view of the immersion probe in FIG. 2A. [Figure 2C] A partially enlarged cross-sectional view of the immersion probe in FIG. 2A. [Figure 2D] A cross-sectional view based on the position of line XX in FIG. 2C. [Figure 2E] Schematic diagram for explaining the change in state of bubbles accompanying narrowing of the facing surface area of ​​the gap of the immersion probe [Figure 2F] Graph showing the relationship between the opposing surface area of ​​the gap of the immersion probe and the viscosity of the liquid sample [Figure 2G] Graph showing the relationship between the opposing surface area of ​​the gap of the immersion probe and the viscosity of the liquid sample [Figure 2H] Graph showing the relationship between the opposing surface area of ​​the gap of the immersion probe and the viscosity of the liquid sample [Figure 2I] Graph showing the relationship between the opposing surface area of ​​the gap of the immersion probe and the viscosity of the liquid sample [Figure 2J] FIG. 1 is an overall perspective view showing a situation in which the absorbance of a liquid sample is measured using the immersion probe of the first embodiment; [Figure 2K] FIG. 13 is a partial perspective view showing a modified example of the immersion probe according to the first embodiment. [Figure 2L]FIG. 13 is a partial perspective view showing an immersion gap structure of another modified example of the immersion probe according to the first embodiment. [Figure 2M] A side view of the immersion gap structure shown in FIG. 2I [Diagram 3] FIG. 3 is a cross-sectional view of an immersion probe according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The relationships between the embodiments and the claims are as follows: Embodiment 1 mainly relates to claims 1 and 3 to 10, and embodiment 2 mainly relates to claim 2. It should be noted that the present invention is not limited to these embodiments, and can be embodied in various forms without departing from the spirit and scope of the present invention. <Prerequisite: Immersion probe>

[0025] The immersion probe according to the present invention is an immersion probe for measuring absorbance. Measurement of absorbance using this immersion probe for measuring absorbance is performed by filling the light path (gap) with a liquid sample, transmitting light, and measuring the transmittance of the light through the liquid sample. Light that passes through the liquid sample is absorbed by solutes in the liquid sample, and the intensity of the transmitted light decreases. By detecting the intensity of the transmitted light, the absorbance is calculated based on the above formula 1.

[0026] In this case, the measurement optical path length, which is the length of the optical path required for measurement in an immersion probe for absorbance measurement, refers to the distance that light passes through the liquid sample, i.e., twice the distance of the gap, and this measurement optical path length varies depending on the characteristics of the liquid sample to be measured and the wavelength of light used in the measurement. In general, the measurement optical path length of an immersion probe is adjusted to a range of several millimeters to several tens of millimeters, and as an example, immersion probes with measurement optical path lengths adjusted to 2 millimeters, 5 millimeters, and 10 millimeters are commercially available.

[0027] In addition, in a liquid immersion probe for measuring absorbance, the area of ​​the surface that comes into contact with the liquid sample filling the optical path and through which light passes is generally on the order of several square millimeters to several tens of square millimeters, for example, 3.0 square millimeters to 30.0 square millimeters.

[0028] When measuring the absorbance of a liquid sample using such an immersion probe for absorbance measurement, the parameters of the measurement optical path length, the contact area of ​​the surface that comes into contact with the liquid sample, and the wavelength of light play important roles. When determining the measurement optical path length and the contact area of ​​the surface that comes into contact with the liquid sample, it is necessary to take into account the viscosity of the liquid sample to prevent air bubbles from accumulating in the gap.

[0029] The wavelengths of light typically used in immersion probes for absorbance measurement are in the ultraviolet range (200-400nm) or visible light range (400-700nm); the specific wavelengths vary depending on the type of object being measured, but commonly used wavelengths include 280nm, 365nm, 405nm, 525nm, 630nm, etc., and there are also immersion probes that use light in the near-infrared range (700-1600nm).

[0030] On the other hand, liquid samples to be measured include semiconductor cleaning fluids, alcohol, semiconductor etching fluids, sterilizing fluids, disinfecting fluids, etc., and have the following approximate viscosities. 1. Alcohol (e.g. whiskey) The viscosity of whiskey varies depending on the type, concentration, temperature, etc., but in general, whiskey's viscosity tends to be higher than water and lower than spirits and beer. Scotch whisky: approx. 1.0-1.5 cP Irish whiskey: approx. 1.0-1.3 cP Bourbon whiskey: approx. 1.2-1.7 cP Canadian whiskey: approx. 1.0-1.4 cP 2. Semiconductor cleaning fluid (e.g. SC-1 (cleaning fluid used in the first stage (Standard Clean-1) of removing organic matter and particles in semiconductor cleaning)) SC-1 is mainly NH 4 OH and H 2 O 2 Its viscosity is generally very low, usually equal to or lower than that of water. The viscosity of water varies depending on conditions such as temperature and pressure, but generally has the following values: At 20°C: 1.002cP At 25°C: 0.890cP At 30°C: 0.798cP 3. Semiconductor etchant = Acid etching solution = HF (hydrofluoric acid): 0.35 cP (25°C) HNO 3 (Nitric acid): 1.2 cP (25°C) H 2 SO 4 (Sulfuric acid): 1.4cP (25℃) 4. Disinfectants and sterilizers The viscosity of disinfectants and sterilants varies depending on the type, temperature, and concentration, but generally falls within the following ranges: Ethanol (alcohol): 1.2 cP Hypochlorous acid water: 1.0 cP Here, cP is a unit of viscosity called centipoise, and 1 cP is 1 / 100 of 1 P (poise), and expressed in SI units, 1 cP = 0.01 Pa·s. <Embodiment 1> This embodiment mainly relates to claims 1, and 3 to 10. <Embodiment 1: Overview of the immersion probe>

[0031] In the immersion probe of this embodiment, a short-gap sensor structure used for measurements in which the spacing of the gap (immersion gap structure part) included in the sensor structure together with the reflecting mirror needs to be smaller than the spacing of a normal gap is configured so that the support column part for supporting the gap structure is located at a position separated from the gap surface. Here, "normal gap" refers to the measurement optical path lengths adjusted to 2 mm, 5 mm, and 10 mm commercially available as described above, and "measurements requiring a gap spacing smaller than the normal gap spacing" are, for example, measurements of the absorbance of water containing a solute.

[0032] In such an immersion probe, even if the gap through which the liquid sample penetrates and remains or passes is made small, it is possible to prevent air bubbles from accumulating in the gap. <Embodiment 1: Liquid immersion probe configuration mainly corresponds to claims 1, 3 to 10>

[0033] As shown in the cross-sectional view of FIG. 2A and the perspective view of FIG. 2B, the immersion probe 0200 of this embodiment includes an optical fiber tube structure 0210 and a sensor structure 0220. The optical fiber tube structure 0210 and the sensor structure 0220 are arranged in a substantially rectangular shape. <Embodiment 1: Optical fiber tube structure Configuration mainly corresponds to claims 1, 3 to 10>

[0034] The optical fiber tube structure 0210 includes two optical fibers 0211 and 0212, a plano-convex lens 0213, and a fiber holder 0215, and the fiber holder 0215 has a cylindrical shape. <Embodiment 1: Optical fiber tube structure Optical fiber Configuration Mainly corresponds to claims 1, 3 to 10>

[0035] Of the two optical fibers 0211, 0212, one optical fiber 0211 is an illumination optical fiber that is connected to a light source 0250 and guides light from the light source 0250 to illuminate the sensor structure 0220, while the other optical fiber 0212 is a light-receiving optical fiber 0212 that receives light reflected by a reflecting mirror 0221 (described later) of the sensor structure 0220 and guides the light to a measuring instrument 0260 such as a spectrometer. The illumination optical fiber 0211 and the light-receiving optical fiber 0212 are fixed such that their respective tips are positioned at predetermined positions in a central hole 0215a of a fiber holder 0215. <Embodiment 1: Optical fiber tube structure, plano-convex lens configuration, mainly corresponds to claims 1, 3 to 10>

[0036] The plano-convex lens 0213 is fixed to the end of the fiber holder 0215 on the sensor structure 0220 side so as to face the respective tip faces of the irradiation optical fiber 0211 and the receiving optical fiber 0212 . <Embodiment 1: Sensor structure configuration mainly corresponds to claims 1, 3 to 10>

[0037] On the other hand, the sensor structure 0220 used in the immersion probe 0200 of this embodiment includes a reflecting mirror 0221, an immersion gap structure portion 0222, and a sensor holder 0225. The sensor holder 0225 has the same diameter as the fiber holder 0215 and is cylindrical with a bottom. <Embodiment 1: Sensor structure, reflecting mirror, configuration, mainly corresponding to claims 1, 3 to 10>

[0038] The reflecting mirror 0221 is fixed to the bottom 0225 b of the central hole 0225 a of the sensor holder 0225 . In this case, the end 0215c of the fiber holder 0215 on the sensor structure 0220 side is formed to have a convex cross section, and the end 0225c of the sensor holder 0225 on the optical fiber tube structure 0210 side is formed to have a concave cross section, and the sensor structure 0220 is fixed to the optical fiber tube structure 0210 by fitting the opposing ends 0215c, 0225c of the fiber holder 0215 and the sensor holder 0225 to each other in the manner of a spigot joint. <Embodiment 1: Sensor structure, liquid immersion gap structure, configuration mainly corresponds to claims 1, 3 to 10>

[0039] The immersion gap structure portion 0222 has cover glasses 0224, immersion gap structures 0224a, and support columns 0226. <Embodiment 1: Sensor structure, liquid immersion gap structure, support column configuration corresponds mainly to claims 1, 3 to 10>

[0040] The support pillars 0226, 0226 are arranged at two locations in the circumferential direction facing each other between the end 0225c of the sensor holder 0225 on the optical fiber tube structure 0210 side and the bottom 0225b to which the reflecting mirror 0221 is fixed. By arranging the support pillars 0226, 0226 in this manner, a space S is formed between the end 0225c and the bottom 0225b of the sensor holder 0225. <Embodiment 1: Sensor structure, liquid immersion gap structure, cover glass, configuration, mainly corresponds to claims 1, 3 to 10>

[0041] The cover glasses 0224, 0224 are fitted into both openings of the central hole 0225a of the sensor holder 0225, the openings facing the space S. <Embodiment 1: Sensor structure, Immersion gap structure, Immersion gap structure, Configuration, Mainly corresponds to claims 1, 3 to 10>

[0042] The immersion gap structures 0224a, 0224a are cylindrical and have the same diameter, and are integrally provided at the center of each of the cover glasses 0224, 0224 so as to protrude into the space S. A short gap (short gap; immersion gap structure portion) 0222 is formed between the end faces 0224b, 0224b of the immersion gap structures 0224a, 0224a facing each other in the space S, through which the liquid as the sample penetrates and remains or passes. The cover glass 0224 to which the immersion gap structure 0224a is integrally formed is made of colorless and transparent quartz, and the contact surfaces of the cover glass 0224 and the immersion gap structure 0224a with the liquid sample are polished, so that the effect on measurements such as absorbance is negligible.

[0043] That is, in the immersion probe 0200 having the short gap 0222 with a short interval, the sensor structure 0220 for the short gap including the short gap 0222 is configured as follows: The sensor structure 0220 for the short gap is configured so that the support pillars 0226 are located between the peripheral portions of the fiber holder 0215 and the sensor holder 0225, which are separated portions, with respect to the end faces 0224b of the immersion gap structures 0224a, which face each other in the space S and form the short gap 0222. <Embodiment 1: Positional relationship between short gap and support column portion Mainly corresponds to claims 1, 3 to 10>

[0044] In this embodiment, as shown in the enlarged cross-sectional view of Figure 2C, for the short gap 0222, which is an immersion gap structure portion formed between each end face 0224b, 0224b of the immersion gap structure 0224a, 0224a, for example, a distance D in the immersion gap axial direction (vertical direction in the figure) of the space S formed in the sensor holder 0225 of the sensor structure 0220 can be considered to be 10 to 15 times the distance d of the short gap 0222. This is because if the spacing D of the space S in the axial direction of the immersion gap is smaller than 10 times the spacing d of the short gap 0222, air bubbles generated in the short gap 0222 will be difficult to escape, and conversely, if the spacing D of the space S in the axial direction of the immersion gap is larger than 15 times the spacing d of the short gap 0222, the amount of light escaping from the immersion gap structures 0224a, 0224a will increase, or the amount of light absorbed by the immersion gap structures 0224a, 0224a will increase, resulting in a reduced amount of received light.

[0045] 2D (a cross-sectional view based on the position of line XX in FIG. 2C), for example, it is considered that the radius R of the fiber holder 0215 (sensor holder 0225 of the sensor structure 0220) of the optical fiber tube structure 0210 is 3 to 5 times the radius r of the end face 0224b of the immersion gap structure 0224a. If the radius R of the fiber holder 0215 is smaller than 3 times the radius r of the end face 0224b of the immersion gap structure 0224a, it becomes difficult for air bubbles generated between the end faces 0224b, 0224b of the immersion gap structures 0224a, 0224a to escape, restricting the flow path around the immersion gap structure 0224a and imposing a burden on the immersion gap structure 0224a. On the other hand, if the radius R of the fiber holder 0215 is greater than five times the radius r of the end face 0224b of the immersion gap structure 0224a, the diameter of the fiber holder 0215 becomes large, limiting the number of attachment points. <Embodiment 1: Relationship between short gap and viscosity of liquid sample (mainly corresponds to claims 1, 3 to 10)

[0046] Here, considering the state of air bubbles in the short gap immersed in the liquid sample, if the diameter M (facing area) of the immersion probe 0200 on the left side of the figure is reduced to the immersion probe 0200 with diameter m on the right side of the figure, as shown in Figure 2E, the short gap 0222 will be filled with the liquid sample L, and the air bubbles will eventually disappear. In other words, it is found that reducing the area of ​​the end face of the immersion gap structure is effective in preventing air bubbles from accumulating in the gap 0222 during measurement of the liquid sample.

[0047] Therefore, in the immersion probe of this embodiment, when measuring the absorbance of a liquid sample using near-infrared light with a wavelength of 1500 nm, the inventors investigated the relationship between the viscosity of the liquid sample when no air bubbles accumulate in the short gap and the area of ​​the end faces (facing area) of the immersion gap structure based on their own experience, assuming that the near-infrared light can travel back and forth through a gap of 0.3 to 1.0 mm with a predetermined reflection intensity. <Relationship between viscosity of liquid sample and gap facing area when the short gap interval is 0.3 millimeters, mainly corresponding to claims 1, 3 to 10>

[0048] As shown in the graph of FIG. 2F, when the short gap interval is 0.3 millimeters, when the viscosity (cP) X of the liquid sample is in the range of 0.0 < X ≤ 0.5, by setting the facing area to satisfy the following formula A, it was found that no bubbles accumulate in the short gap. Formula A Y ≤ -(22.0 / 0.5) · X + 30.0 Also, when the viscosity (cP) X of the liquid sample is in the range of 0.5 < X ≤ 1.0, by setting the facing area to satisfy the following formula B, it was found that no bubbles accumulate in the short gap. Formula B Y ≤ -(5.0 / 0.5) · X + 8.0 Furthermore, when the viscosity (cP) X of the liquid sample is in the range of 1.0 < X ≤ 1.5, by setting the facing area to satisfy the following formula C, it was found that no bubbles accumulate in the short gap. Formula C Y ≤ -(1.0 / 0.5) · X + 3.0 <Relationship between viscosity of liquid sample and gap facing area when the short gap interval is 0.5 millimeters, mainly corresponding to claims 1, 3 to 10>

[0049] As shown in the graph of FIG. 2G, when the short gap interval is 0.5 millimeters, when the viscosity (cP) X of the liquid sample is in the range of 0.0 < X ≤ 0.5, by setting the facing area to satisfy the following formula D, it was found that no bubbles accumulate in the short gap. Formula D Y ≤ -(21.0 / 0.5) · X + 30.0 Also, when the viscosity (cP) X of the liquid sample is in the range of 0.5 < X ≤ 1.0, by setting the facing area to satisfy the following formula E, it was found that no bubbles accumulate in the short gap. Formula E Y ≤ -(5.0 / 0.5) · X + 9.0 Furthermore, when the viscosity (cP) X of the liquid sample is in the range of 1.0 < X ≤ 1.5, by setting the facing area to satisfy the following formula F, it was found that no bubbles accumulate in the short gap. Formula F Y ≤ -(1.0 / 0.5) · X + 4.0 <Relationship between Viscosity of Liquid Sample and Gap Opposing Area When Short Gap Interval is 0.7 Millimeters, Mainly Corresponding to Claims 1, 3 to 10>

[0050] As shown in the graph of FIG. 2H, when the short gap interval is 0.7 millimeters, when the viscosity (cP) X of the liquid sample is in the range of 0.0 < X ≤ 0.5, by setting the opposing area to satisfy the following formula G, it was found that no bubbles accumulate in the short gap. Formula G: Y ≤ -(20.0 / 0.5)·X + 30.0 Also, when the viscosity (cP) X of the liquid sample is in the range of 0.5 < X ≤ 1.0, by setting the opposing area to satisfy the following formula H, it was found that no bubbles accumulate in the short gap. Formula H: Y ≤ -(5.0 / 0.5)·X + 10.0 Furthermore, when the viscosity (cP) X of the liquid sample is in the range of 1.0 < X ≤ 1.5, by setting the opposing area to satisfy the following formula I, it was found that no bubbles accumulate in the short gap. Formula I: Y ≤ -(1.0 / 0.5)·X + 5.0 <Relationship between Viscosity of Liquid Sample and Gap Opposing Area When Short Gap Interval is 1.0 Millimeters, Mainly Corresponding to Claims 1, 3 to 10>

[0051] As shown in the graph of FIG. 2I, when the short gap interval is 1.0 millimeters, when the viscosity (cP) X of the liquid sample is in the range of 0.0 < X ≤ 0.5, by setting the opposing area to satisfy the following formula J, it was found that no bubbles accumulate in the short gap. Formula J: Y ≤ -(18.0 / 0.5)·X + 30.0 Also, when the viscosity (cP) X of the liquid sample is in the range of 0.5 < X ≤ 1.0, by setting the opposing area to satisfy the following formula K, it was found that no bubbles accumulate in the short gap. Formula K: Y ≤ -(6.0 / 0.5)·X + 12.0 Furthermore, when the viscosity (cP) X of the liquid sample is in the range of 1.0 < X ≤ 1.5, by setting the opposing area to satisfy the following formula L, it was found that no bubbles accumulate in the short gap. Formula LY≦-(1.0 / 0.5)·X+6.0

[0052] Therefore, in the immersion probe of this embodiment, when measuring the absorbance of a liquid sample using near-infrared light with a wavelength of 1500 nm, assuming that the near-infrared light can travel back and forth through a gap with a spacing of 0.3 to 1.0 mm with a predetermined reflection intensity, it is considered preferable that the area of ​​the opposing end faces of the immersion gap structure that constitutes the short gap be no less than 3.14 square millimeters (note: radius 1 mm) and no more than 28.26 square millimeters (note: radius 3 mm). The immersion probe of this embodiment having such a short gap configuration can be used, for example, to measure liquid samples whose absorbance is 1 / 500 or more, or to measure transmittance when the relationship between the liquid and light is such that the transmittance is 10% or more and 80% or less. <Embodiment 1: Measurement of absorbance (mainly corresponds to claims 1, 3 to 10)>

[0053] When using an immersion probe having such a configuration to measure, for example, absorbance, the immersion probe 0200 is set using a stand or the like (not shown) so that the short gap 0222 of the immersion probe 0200 is immersed in the liquid sample L contained in a beaker 0270, as shown in the oblique view of Figure 2J.

[0054] In this state, the light introduced from the light source 0250 via the irradiation optical fiber is focused by the plano-convex lens of the optical fiber tube structure and transmitted through the liquid filled in the short gap 0222, and the light reflected by the reflective mirror of the sensor structure is received via the liquid sample in the short gap 0222 and the plano-convex lens, and is guided to a light intensity measuring unit 0260 such as a spectrometer, and the absorbance is calculated based on the above formula 1. <Embodiment 1: Measurement of transmittance and concentration (mainly corresponds to claims 1, 3 to 10)>

[0055] Here, absorbance represents the degree to which a liquid sample absorbs light, while transmittance represents the proportion of light that passes through the liquid sample. If a liquid sample does not absorb any light (absorbance is 0), the transmittance will be 1.0, so the transmittance can be calculated by subtracting the exponential function of absorbance based on the above formula 1 from 1.0. Furthermore, as can be seen from A=εcl in Equation 1, the concentration of the liquid sample can be calculated based on the absorbance calculated above, the molar absorption coefficient ε, and the molar concentration c of the liquid sample. <Embodiment 1: Liquid immersion probe and other configurations mainly correspond to claims 1, 3 to 10>

[0056] Next, another configuration (modification) of the immersion probe according to this embodiment will be described. As shown in the enlarged perspective view of FIG. 2K, in the immersion probe 0200A according to this modification, the diameters of the fiber holder 0215A of the optical fiber tube structure 0210A and the sensor holder 0225A of the sensor structure 0220A are each narrowed so that both holders 0215A, 0225A function as an immersion gap structure constituting an immersion gap structure portion. That is, the gap 0222A between the end faces 0215Ab, 0225Ab of the fiber holder 0215A and the sensor holder 0225A is set to 0.3 to 1.0 mm, and the area of ​​the mutually facing end faces 0215Ab, 0225Ab of both holders 0215A, 0225A is set to 3.14 square millimeters (note: radius 1 mm) to 28.26 square millimeters (note: radius 3 mm). Furthermore, the support pillar portion 0226A for supporting the structure of the gap 0222A is configured to be positioned at a location spaced apart from the end faces 0215Ab, 0225Ab of both holders 0215A, 0225A that constitute the gap 0222A, i.e., configured to ensure a wide area around the gap 0222A for the liquid sample to remain or pass through. In this way, the immersion probe 0200A according to another configuration (variation) of this embodiment can also prevent air bubbles from accumulating in the gap. <Embodiment 1: Liquid immersion probe and other configurations mainly corresponding to claims 1, 3 to 10>

[0057] Next, another configuration (another modified example) of the immersion probe according to this embodiment will be described. The perspective view of Fig. 2L and the side view of Fig. 2M show the cover glasses 0224B, 0224B of the immersion probe according to this modified example and the immersion gap structures 0224Ba, 0224Ba integrally provided with these cover glasses 0224B, 0224B. The immersion gap structures 0224Ba, 0224Ba of the immersion probe according to this modified example are all cylindrical with the same diameter, and the end faces 0224Bb, 0224Bb of the immersion gap structures 0224Ba, 0224Ba that form the short gap (short gap; immersion gap structure portion) 0222B through which the liquid sample penetrates and remains or passes are configured to be inclined to each other with respect to the axis C of the immersion probe. In an immersion probe according to another configuration (variant example) of this embodiment in which the end faces 0224Bb, 0224Bb of the immersion gap structures 0224Ba, 0224Ba that form the short gap 0222B are inclined relative to the axis C of the immersion probe, air bubbles become even more likely to come out from within the short gap 0222B. <Embodiment 1: Liquid immersion probe Mainly corresponds to claims 1, 3 to 10 Effects>

[0058] In the immersion probe of this embodiment, even if the gap through which the sample liquid penetrates and remains or passes is made small, it is possible to prevent air bubbles from accumulating in the gap, thereby achieving the effect of making it possible to measure the transmittance and absorptance of the measurement light of the liquid sample with high accuracy. <Embodiment 2>

[0059] This embodiment mainly relates to claim 2. <Embodiment 2: Overview of the immersion probe>

[0060] The immersion probe of this embodiment is based on embodiment 1, and is characterized in that the sensor structure having a short gap, which is the immersion gap structure part, is configured to be freely attached and detached to the optical fiber tube structure.

[0061] In such an immersion probe, by having a plurality of sensor structures with different gap spacings, it is possible to select and use a sensor structure with an appropriate gap spacing when measuring the absorbance, transmittance, etc. of a liquid sample. <Embodiment 2: Liquid immersion probe configuration mainly corresponds to claim 2>

[0062] 3, the immersion probe 0300 of this embodiment is characterized in that, compared to the immersion probe of embodiment 1, a male thread 0315d is formed on the outer circumferential surface of an end 0315c of the fiber holder 0315 that is formed in a convex cross section on the sensor structure 0320 side, while a female thread 0325d is formed on the inner circumferential surface of an end 0325c of the sensor holder 0325 that is formed in a concave cross section on the optical fiber tube structure 0310 side. In other words, the male thread 0315d of the fiber holder 0315 and the female thread 0325d of the sensor holder 0325 can be screwed into and out of each other, thereby making it possible to detachably attach the sensor structure 0320 to and from the optical fiber tube structure 0310. <Embodiment 1: Liquid immersion probe Mainly corresponds to claims 1, 3 to 10 Effects>

[0063] The liquid immersion probe of this embodiment has the advantage that a plurality of sensor structures with different gap spacings are prepared, and when measuring the absorbance, transmittance, etc. of a liquid sample, a sensor structure with a gap spacing appropriate for the liquid sample can be selected from the plurality of sensor structures depending on the type of liquid sample, and attached to the optical fiber tube structure and used. [Explanation of symbols]

[0064] 0200 Immersion Probe 0210 Optical fiber tube structure 0211 Optical fiber for irradiation 0212 Receiving optical fiber 0220 Sensor structure 0221 Reflective mirror 0222 Gap (liquid immersion gap structure part) 0224a Sensor structure for short gap 0224b Gap surface 0226 Support column part 0250 Light source 0260 Light Intensity Measurement Unit

Claims

1. a sensor structure including a reflecting mirror and an immersion gap structure; an optical fiber tube structure that houses an optical fiber for introducing light from a light source into the sensor structure and guiding the light reflected by a reflection mirror of the sensor structure to a light intensity measuring unit; As a sensor structure for a short gap used in a measurement in which a large amount of light is absorbed by a liquid in which the sensor structure is immersed and therefore the immersion gap needs to be made smaller than a normal immersion gap in which the amount of absorption is small, An immersion probe that can be used is configured so that the reflecting mirror side to form a gap and the support pillar portion for supporting the structure on the light introduction side are located at a position spaced apart from the gap surface.

2. 2. The liquid immersion probe according to claim 1, wherein the sensor structure is detachably attached to the optical fiber tube structure.

3. 2. The liquid immersion probe according to claim 1, wherein the amount of absorption is large refers to a relationship between the light and the liquid in which the absorbance is 1 / 500 or more.

4. 2. The immersion probe according to claim 1, wherein the short gap is a gap having a gap interval of 1 mm or less and 0.3 mm or more.

5. 2. The immersion probe of claim 1, wherein the facing area of ​​the short gap is between 3.14 square millimeters (note: radius 1 mm) and 28.26 square millimeters (note: radius 3 mm).

6. 6. The liquid immersion probe according to claim 1, wherein the liquid and the light have a relationship of transmittance of 10% or more and 80% or less.

7. A short gap sensor structure that can be used with the immersion probe according to claim 1.

8. 6. A method for measuring absorbance of a liquid, comprising the steps of: measuring the absorbance of a liquid by using the liquid immersion probe according to claim 4.

9. A method for measuring the transmittance of a liquid, comprising the steps of: measuring the transmittance of a liquid by using the liquid immersion probe according to claim 4 or 5.

10. A concentration measuring method for measuring a concentration of a solution by using the immersion probe according to claim 4 or 5.

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