ATR Prism

Abstract

To provide an ATR PRISM which is not susceptible to light detection accuracy deterioration.SOLUTION: An ATR prism provided herein is made of a material having an internal transmittance of 90% or greater in a wavelength range of 8-10 μm at a thickness of 2 mm. The ATR prism has a first surface including a first total reflection surface, a second surface including a second total reflection surface, and a recess formed on the first and second surfaces.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an ATR prism. [Background technology]

[0002] The ATR (Attenuated Total Reflection) method is known as a method for non-invasively acquiring biological information such as blood glucose levels. In the ATR method, when total reflection occurs at an ATR prism placed in contact with the object to be measured, the evanescent wave seeping out from the total reflection surface is used to acquire the absorption spectrum of the object to be measured.

[0003] For example, Patent Document 1 discloses a measuring device equipped with an ATR prism. The ATR prism has an entrance surface, a first total reflection surface, a second total reflection surface, and an exit surface. With the first total reflection surface in contact with a living body, this ATR prism causes a probe light incident from the entrance surface to be repeatedly totally reflected between the first total reflection surface and the second total reflection surface. Thereafter, the probe light exits from the exit surface and is converted into a detection signal by a photodetector (see paragraphs 0039 to 0041 of the same document).

[0004] The above-mentioned measuring device includes a first support and a second support for supporting the ATR prism. The first support is a box-shaped member for supporting components such as an optical fiber. The second support is a block-shaped member having a recess for inserting and fixing the ATR prism (see paragraphs 0170 to 0172 and FIG. 16 of the same document). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-74068 Summary of the Invention [Problem to be solved by the invention]

[0006] In the conventional measuring device, when the ATR prism is accommodated in the recess of the second support part, the second total reflection surface of the ATR prism is configured to contact the bottom surface of the recess. If the second total reflection surface is in contact with another member in this way, the total reflection of the probe light at the second total reflection surface is hindered, and there is a risk that the light detection accuracy of the ATR prism will decrease. Here, the light detection accuracy refers to the signal-to-noise ratio (SN ratio) of the light component extracted from the exit surface of the ATR prism.

[0007] The present invention has been made in consideration of the above circumstances, and has as its technical object to prevent a decrease in the light detection accuracy of the ATR prism. [Means for solving the problem]

[0008] The present invention has been made to solve the above-mentioned problems, and is an ATR prism made of a material having an internal transmittance of 90% or more in a wavelength range of 8 to 10 μm at a thickness of 2 mm, and characterized in that it comprises a first surface including a first total reflection surface, a second surface including a second total reflection surface, and a recess formed on the first surface or the second surface.

[0009] According to this configuration, a total reflection surface can be provided in the recess formed on the first surface or the second surface. This makes it possible to prevent other components of the measuring device equipped with the ATR prism and foreign matter such as dust from coming into contact with the total reflection surface formed in the recess. Therefore, it is possible to cause the desired total reflection on the total reflection surface of the recess, and to prevent a decrease in the light detection accuracy of the ATR prism.

[0010] In the ATR prism of the present invention, the first surface may be a contact surface that contacts the object to be measured, the second surface may be a non-contact surface that does not contact the object to be measured, and the recess may be formed on the second surface.

[0011] The first surface is brought into contact with the object to be measured, and the first total reflection surface of the first surface and the second total reflection surface of the second surface cause repeated total reflection of light, thereby allowing the ATR prism to detect information about the object to be measured. The second surface does not come into contact with the object to be measured, and does not come into contact with other components of the measuring device or foreign matter such as dust, so the ATR prism can obtain this information without reducing the light detection accuracy.

[0012] In the ATR prism according to the present invention, the recess may have a bottom surface, the bottom surface may include the second total reflection surface, and a covering member may be provided to cover the recess at a position spaced apart from the bottom surface. By covering the recess with the covering member, it is possible to protect the second total reflection surface at the bottom surface from contact with other members of the measuring device and foreign matter such as dust.

[0013] In the ATR prism according to the present invention, the material may be glass. In this case, the glass may be chalcogenide glass. The chalcogenide glass may contain, in mole percentages, 50-80% S, 0-40% Sb (but not including 0%), 0-18% Ge (but not including 0%), 0-20% Sn, and 0-20% Bi. Alternatively, the chalcogenide glass may contain, in mole percentages, 4-80% Te, 0-50% Ge (but not including 0%), and 0-20% Ga.

[0014] In the ATR prism according to the present invention, the distance between the bottom surface of the recess and the covering member may be 0.1 to 3.0 mm, which allows the second total reflection surface provided on the bottom surface of the recess to be reliably protected by the covering member.

[0015] In the ATR prism according to the present invention, the recess may have a wall surface surrounding the entire circumference of the bottom surface. By surrounding the entire circumference of the bottom surface with the wall surface, it is possible to reliably prevent foreign matter from coming into contact with the second total reflection surface provided on the bottom surface.

[0016] In the ATR prism of the present invention, the bottom surface of the recess is configured in a rectangular shape having four sides, and the recess has wall surfaces surrounding the bottom surface, and the wall surfaces may have only two wall surfaces corresponding to two opposing sides of the bottom surface.

[0017] According to this configuration, the bottom surface of the recess is surrounded by only two walls, so that other components of the measuring device can be prevented from contacting the bottom surface of the recess. Furthermore, the remaining two sides of the bottom surface, which do not have walls, can be determined with a distance therebetween without being restricted by the walls. This makes it possible to ensure a larger area of ​​the bottom surface, i.e., the area of ​​the second total reflection surface, compared to the case where the entire circumference of the bottom surface is surrounded by walls.

[0018] In the ATR prism according to the present invention, the distance between the bottom surface of the recess and the first surface may be 0.1 to 3.0 mm, which allows effective total reflection of light between a first total reflection surface of the first surface and a second total reflection surface provided on the bottom surface of the recess. Effect of the Invention

[0019] According to the present invention, it is possible to prevent a decrease in the light detection accuracy of the ATR prism. [Brief description of the drawings]

[0020] [Figure 1] 1 is a cross-sectional view of a measurement device including an ATR prism according to a first embodiment. [Diagram 2] FIG. 2 is an exploded perspective view of an ATR prism. [Diagram 3] FIG. 2 is a cross-sectional view of an ATR prism. [Figure 4] 4 is a cross-sectional view showing a step in a method for manufacturing an ATR prism. [Diagram 5] 4 is a cross-sectional view showing a step in a method for manufacturing an ATR prism. [Figure 6] FIG. 11 is a cross-sectional view of a measurement device including an ATR prism according to a second embodiment. [Figure 7]FIG. 2 is an exploded perspective view of an ATR prism. [Figure 8] FIG. 2 is a bottom view of the ATR prism. [Figure 9] 4 is a cross-sectional view showing a step in a method for manufacturing an ATR prism. [Figure 10] FIG. 11 is a cross-sectional view of a measurement device including an ATR prism according to a third embodiment. [Figure 11] FIG. 13 is an exploded perspective view of an ATR prism according to a fourth embodiment. [Figure 12] FIG. 2 is a partially enlarged side view of the ATR prism. [Figure 13] FIG. 13 is an exploded perspective view of an ATR prism according to a fifth embodiment. [Figure 14] FIG. 2 is a partially enlarged side view of the ATR prism. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figures 1 to 5 show a measurement device including an ATR prism and a method for manufacturing an ATR prism according to a first embodiment.

[0022] 1, the measurement device 1 mainly includes an ATR prism 2, a light source 3, and a light receiving unit 4. As shown in Fig. 1 and Fig. 2, the ATR prism 2 includes an entrance unit 5 into which light from the light source 3 is incident, reflecting units 6a and 6b that reflect the incident light, an exit unit 7 that outputs the light reflected by the reflecting units 6a and 6b, a covering member 8 that covers a part of the reflecting unit 6b, and a side surface 9 formed between the entrance unit 5 and the exit unit 7.

[0023] The incident portion 5 includes an inclined surface 5a inclined with respect to the reflecting portions 6a and 6b. The inclination angle θ1 of the inclined surface 5a is, for example, 45° or 60°, but is not limited to these angles and can be appropriately set depending on the shape and dimensions of the ATR prism 2.

[0024] eachThe reflecting portions 6a, 6b include a first reflecting portion 6a and a second reflecting portion 6b. The first reflecting portion 6a is formed on one surface (hereinafter referred to as the "first surface") 2a of the ATR prism 2. The second reflecting portion 6b is formed on the other surface (hereinafter referred to as the "second surface") 2b of the ATR prism 2. The second surface 2b is located on the opposite side to the first surface 2a in the thickness direction of the ATR prism 2 (the direction indicated by the symbol T in FIG. 2; the same applies below). The length dimension L1 of the first surface 2a is larger than the length dimension L2 of the second surface 2b. The area of ​​the first surface 2a is also larger than the area of ​​the second surface 2b.

[0025] The width dimension W of the first surface 2a and the second surface 2b is, for example, 2 to 15 mm, and preferably 3 to 12 mm. The length dimension L1 of the first surface 2a (first reflecting portion 6a) of the ATR prism 2 is, for example, 5 to 30 mm, and preferably 7 to 27 mm. The length dimension L2 of the second surface 2b (second reflecting portion 6b) of the ATR prism 2 is, for example, 3 to 20 mm, and preferably 5 to 17 mm. The distance between the first surface 2a and the second surface 2b, i.e., the thickness dimension T of the ATR prism 2, is, for example, 1 to 10 mm, and preferably 2 to 8 mm.

[0026] The first reflecting portion 6a includes a first total reflection surface that reflects the light introduced into the ATR prism 2 from the incident portion 5. The first total reflection surface is formed on the entire surface of the first surface 2a, but is not limited thereto, and the first total reflection surface may be formed on a part of the first surface 2a. The first total reflection surface is a contact surface that comes into contact with a biological sample (hereinafter simply referred to as a "sample") S, which is the measurement object.

[0027] As shown in FIGS. 1 and 2, the second reflecting portion 6b includes a recess 10 covered by a covering member 8 and an exposed surface 11 surrounding the recess 10. As shown in FIG.

[0028] The recess 10 has a bottom surface 12 and a recess 12 surrounding the bottom surface 12. each First wall surfaces 13a to 13d, a support surface 14 that supports the covering member 8, and a wall surrounding the support surface 14 each and second wall surfaces 15a to 15d.

[0029] The bottom surface 12 includes a second total reflection surface that reflects the light introduced into the ATR prism 2 from the incident portion 5. In this embodiment, the entire surface of the bottom surface 12 is configured as the second total reflection surface, but this is not limited thereto, and the second total reflection surface may be formed on a part of the bottom surface 12. This second total reflection surface is a non-contact surface that does not contact the sample S.

[0030] As shown in Fig. 2, the bottom surface 12 is configured in a rectangular shape having four sides, but is not limited to this shape. The length dimension L3 of the bottom surface 12 (see Fig. 1) is preferably 1 to 19 mm, more preferably 2 to 18 mm. The width dimension W1 of the bottom surface 12 is preferably 1 to 15 mm, more preferably 1.5 to 14 mm.

[0031] The distance between the exposed surface 11 and the bottom surface 12, i.e., the depth D of the recess 10 (see FIG. 3), is preferably 0.5 to 5 mm, and more preferably 1 to 4 mm. The distance between the bottom surface 12 and the first surface 2a, i.e., the thickness T1 of the ATR prism 2 at the location where the recess 10 is formed (see FIG. 3) is preferably 1 to 5 mm, and more preferably 2 to 4 mm. If the thickness T1 is within the above range, the number of times that the incident probe light is repeatedly totally reflected between the first total reflection surface and the second total reflection surface can be increased, thereby improving the accuracy of the detection signal while maintaining the strength of the ATR prism 2.

[0032] Each of the first walls 13a to 13d includes four walls surrounding the entire circumference (four sides) of the bottom surface 12. Each of the first walls 13a to 13d is intended to separate the bottom surface 12 from the covering member 8. Although each of the first walls 13a to 13d is illustrated as being perpendicular to the bottom surface 12, this is not limiting. Each of the first walls 13a to 13d may be inclined at an angle θ3 with respect to the bottom surface 12, as shown by a two-dot chain line in FIG. 3. If this inclination angle θ3 is 60° or more and less than 90°, the glass molded body can be easily released from the second molding die 17 after the glass molded body is annealed and cooled in the molding step described below.

[0033] The support surface 14 supports the covering member 8 at a position spaced apart from the bottom surface 12. The support surface 14 is formed in a midway portion of the recess 10 in the depth direction. The support surface 14 is a surface that is approximately parallel to the bottom surface 12. The support surface 14 is configured in a rectangular shape having four sides, but is not limited to this shape. The support surface 14 supports the covering member 8 by coming into contact with a portion of the covering member 8.

[0034] Each of the second wall surfaces 15a-15d includes four wall surfaces so as to surround the entire periphery (four sides) of the support surface 14. Each of the second wall surfaces 15a-15d covers an end face of the covering member 8 supported by the support surface 14. The length dimension of each of the second wall surfaces 15a-15d in the thickness direction of the ATR prism is preferably equal to or smaller than the thickness dimension of the covering member 8. As shown in FIG. 3, each of the second wall surfaces 15a-15d does not have to be perpendicular to the support surface 14, and may be inclined at an angle θ3 with respect to the support surface 14, as shown by the two-dot chain line.

[0035] The exposed surface 11 is formed so as to surround the entire circumference of the recess 10. The exposed surface 11 is configured in a rectangular shape, but is not limited to this shape. Other components of the measurement device 1 (such as a support member for the ATR prism 2) may come into contact with the exposed surface 11.

[0036] The emission part 7 includes an inclined surface 7a inclined with respect to the reflecting parts 6a and 6b. The inclination angle θ2 (see FIG. 2) of the inclined surface 7a is, for example, 45° or 60°, but is not limited to these angles and can be appropriately set depending on the shape and dimensions of the ATR prism 2.

[0037] 1 and 2, the covering member 8 is a rectangular plate-like member having four sides, but is not limited to this shape. The covering member 8 is made of, for example, a glass plate, but is not limited to this material and may be a ceramic plate, a resin plate, or a metal plate.

[0038] The area of ​​the covering member 8 is larger than the area of ​​the bottom surface 12 of the recess 10 of the ATR prism 2. The thickness dimension of the covering member 8 is preferably 1 to 3 mm, and more preferably 1.5 to 2.5 mm. The distance D1 between the covering member 8 and the bottom surface 12 of the recess 10 is preferably 0.1 to 3.0 mm, and more preferably 0.2 to 2.5 mm.

[0039] The covering member 8 is fixed to the support surface 14 of the recess 10, for example, via an adhesive. However, the covering member 8 may be fixed to the support surface 14 by optical contact, soldering, or other means.

[0040] The side surface 9 separates the entrance portion 5 and the exit portion 7 in the longitudinal direction (the direction indicated by the symbol L1 or L2 in Figs. 1 and 2; the same applies below) of the ATR prism 2. The side surface 9 also separates the first reflecting portion 6a and the second reflecting portion 6b in the thickness direction of the ATR prism 2. The angle between the side surface 9 and the reflecting surfaces of the reflecting portions 6a and 6b is 90°, but this angle is not limited to this embodiment.

[0041] The ATR prism 2 is made of a material having an internal transmittance of 90% or more, preferably 91% or more, and more preferably 92% or more in a wavelength range of 8 to 10 μm when the thickness is, for example, 2 mm. Suitable materials for the ATR prism include, for example, crystalline materials such as germanium and silicon, and glass.

[0042] The glass used as the material of the ATR prism may be, for example, chalcogenide glass, which may contain, in mole percentage, 50-80% S, 0-40% Sb (but not including 0%), 0-18% Ge (but not including 0%), 0-20% Sn, and 0-20% Bi.

[0043] In the chalcogenide glass, the S content is, in mole percentage, more preferably 55% or more, even more preferably 60% or more, more preferably 75% or less, and even more preferably 70% or less. If the S content in the glass is less than 50%, it becomes difficult to vitrify. On the other hand, if the S content in the glass exceeds 80%, the weather resistance of the glass decreases, and the environment in which the ATR prism can be used is restricted.

[0044] In the chalcogenide glass, the Sb content is, in mole percentage, more preferably 5% or more, even more preferably 10% or more, more preferably 35% or less, even more preferably 33% or less. If the glass does not contain Sb or if the Sb content exceeds 40%, vitrification becomes difficult.

[0045] In the chalcogenide glass, the Ge content is more preferably 2% or more, even more preferably 4% or more, more preferably 20% or less, even more preferably 15% or less, in mole percentage. If the glass does not contain Ge, it is difficult to vitrify. On the other hand, if the Ge content in the glass exceeds 18%, Ge-based crystals are precipitated from the glass, making it difficult to obtain an internal transmittance that satisfies the characteristics of an ATR prism.

[0046] In the chalcogenide glass, the Sn content is, in mole percentage, more preferably 1% or more, even more preferably 5% or more, more preferably 15% or less, and even more preferably 10% or less. Sn in the glass is a component that promotes vitrification. However, if the Sn content in the glass exceeds 20%, vitrification becomes difficult.

[0047] In the chalcogenide glass, the content of Bi is, in mole percentage, more preferably 0.5% or more, even more preferably 2% or more, more preferably 10% or less, and even more preferably 8% or less. Bi in the glass is a component that suppresses the energy required for vitrification of the raw material when melting the glass. On the other hand, if the content of Bi in the glass exceeds 20%, Bi-based crystals are precipitated in the glass, making it difficult to obtain an internal transmittance that satisfies the characteristics of an ATR prism.

[0048] The composition is not limited to the above, and the chalcogenide glass may contain, in mole percentage, 4 to 80% Te, 0 to 50% Ge (but not including 0%), and 0 to 20% Ga.

[0049] In the chalcogenide glass, the content of Te is, in mole percentage, more preferably 10% or more, even more preferably 20% or more, more preferably 75% or less, even more preferably 70% or less. If the content of Te in the glass is less than 4%, it becomes difficult to vitrify. On the other hand, if the content of Te in the glass exceeds 80%, Te-based crystals are precipitated from the glass, making it difficult to obtain an internal transmittance that satisfies the characteristics of an ATR prism.

[0050] In the chalcogenide glass, the Ge content is more preferably 1% or more, even more preferably 5% or more, more preferably 40% or less, even more preferably 30% or less, in mole percentage. If the glass does not contain Ge, it is difficult to vitrify. On the other hand, if the Ge content in the glass exceeds 50%, Ge-based crystals are precipitated from the glass, making it difficult to obtain an internal transmittance that satisfies the characteristics of an ATR prism.

[0051] In the chalcogenide glass, the Ga content is, in mole percentage, more preferably 0.1% or more, even more preferably 1% or more, more preferably 15% or less, even more preferably 10% or less. By including Ga in the glass, the vitrification range can be expanded and the thermal stability (vitrification stability) of the glass can be increased.

[0052] In order to enable checking of the processing quality and internal component quality of the ATR prism by an optical instrument using near-infrared light, the above glass has an internal transmittance of preferably 10% or more, more preferably 30% or more, and even more preferably 50% or more in a wavelength band of 1 to 2 μm at a thickness of 2 mm. This makes it possible to apply a high-quality ATR prism.

[0053] As shown in Fig. 1, the light source 3 is disposed in the vicinity of the entrance portion 5 of the ATR prism 2 so as to face the inclined surface 5a of the entrance portion 5. The light source 3 is configured to irradiate, for example, infrared light to the entrance portion 5 of the ATR prism 2. The light source 3 is configured by a device including, for example, a quantum cascade laser that emits laser light in the infrared region, but is not limited to this embodiment. Note that the infrared light referred to here refers to light having a wavelength range of 8 to 10 µm.

[0054] As shown in FIG. 1, the light receiving section 4 is disposed in the vicinity of the light emitting section 7 so as to face the inclined surface 7a of the light emitting section 7.

[0055] A method for measuring biological information using the measuring device 1 will be described below. In Fig. 1, light propagating from the light source 3 to the light receiving unit 4 is indicated by a series of arrows. As shown in Fig. 1, light (infrared light) emitted from the light source 3 is introduced into the ATR prism 2 from the entrance unit 5. This light propagates to the exit unit 7 while repeatedly reflecting (total internal reflection) between the first reflecting unit 6a and the second reflecting unit 6b.

[0056] When the sample S is in contact with the first reflecting portion 6a, the light does not leave the ATR prism 2 but is totally reflected at the contact surface between the first reflecting portion 6a of the ATR prism 2 and the sample S. In this case, the light seeps into the sample S side by a small distance (evanescent wave), and if the light is absorbed by the sample S at that time, the reflected light is attenuated according to the concentration of the absorbing substance, so that the absorption spectrum of the measurement target contained in the sample S can be obtained. Since there is a correlation between the infrared absorption spectrum measured based on the light that leaves the emission portion 7 and reaches the light receiving portion 4 and the state inside the sample S, it is possible to obtain biological information, such as the blood glucose level, contained in the sample S based on this infrared absorption spectrum.

[0057] A method for manufacturing the ATR prism 2 having the above-mentioned configuration from glass will be described below. This method includes a preparation step of preparing a base glass material, and a molding step of molding the ATR prism 2 from the base glass material.

[0058] In the preparation step, a base glass is prepared, for example, a chalcogenide glass having a glass composition of, in molar percentage, S 60%, Sb 30%, Ge 5%, and Sn 5%, or a chalcogenide glass having a glass composition of, in molar percentage, Te 70%, Ge 25%, and Ga 5%. As shown in FIG. 4, the base glass 20 is configured in a rectangular parallelepiped shape, but is not limited to this shape. In the preparation step, the entire surface of the base glass 20 or a part thereof may be polished (mirror-finished).

[0059] In the molding step, the mother glass 20 is heated and pressed by a molding die to form the ATR prism 2. As shown in Figures 4 and 5, the molding dies 16-19 used in the molding step include a first molding die 16, a second molding die 17, a third molding die 18, and a fourth molding die 19. The molding dies 16-19 are made of a metal such as a cemented carbide alloy.

[0060] The forming dies 16 to 19 are preferably placed in a metal chamber filled with an inert gas (such as nitrogen gas). A heater for heating the forming dies 16 to 19 and the base glass 20 is provided outside the chamber.

[0061] The first molding die 16 is located above the second molding die 17. The first molding die 16 has a molding surface 16a that molds the first reflecting portion 6a (first surface 2a) of the ATR prism 2.

[0062] The second molding die 17 has a molding surface 17a for molding the second reflecting portion 6b (second surface 2b) of the ATR prism 2. This molding surface 17a includes an exposed surface molding portion 17b for molding the exposed surface 11 of the second reflecting portion 6b, a bottom surface molding portion 17c for molding the bottom surface 12 of the second reflecting portion 6b, a first wall surface molding portion 17d for molding the first wall surfaces 13a to 13d, a supporting surface molding portion 17e for molding the supporting surface 14, and a second wall surface molding portion 17f for molding the second wall surfaces 15a to 15d.

[0063] The third molding die 18 is formed in a cylindrical shape so that a part of the second molding die 17 is inserted into the inside of the third molding die 18. The third molding die 18 includes a molding surface 18a which molds the inclined surface 5a of the entrance portion 5 of the ATR prism 2, and a molding surface 18b which molds the inclined surface 7a of the exit portion 7. In addition, the third molding die 18 includes a molding surface (not shown) which molds the side surface 9 of the ATR prism 2.

[0064] The fourth molding die 19 is configured in a cylindrical shape and includes a first cylindrical portion 19a into which a part of the first molding die 16 is inserted, and a second cylindrical portion 19b into which the third molding die 18 is inserted. The first cylindrical portion 19a of the fourth molding die 19 functions as a guide portion that moves the first molding die 16 in the up and down direction with a part of the first molding die 16 inserted therein.

[0065] In the forming step, the base glass 20 is placed on the forming surface 17a of the second forming die 17. Next, the first forming die 16 inserted into the first cylindrical portion 19a of the fourth forming die 19 is lowered to approach the second forming die 17. Thereafter, the base glass 20 is pressed by the first forming die 16 and the second forming die 17 while the forming die 16-19 and the base glass 20 are heated by a heater.

[0066] In the molding step, the mother glass 20 is heated to, for example, 160 to 260°C. The heated mother glass 20 softens and is deformed by the pressure applied by the first molding die 16. The molding surfaces (including molding surfaces not shown) 16a, 17a, 18a, and 18b of the first molding die 16 to the third molding die 18 come into contact with the softened mother glass 20 and mold the entrance part 5, the reflecting parts 6a and 6b, the exit part 7, and the side surface 9 of the ATR prism 2 (see FIG. 5). Thereafter, the molding dies 16 to 19 are cooled, and the glass molded body is gradually cooled, thereby completing the ATR prism 2.

[0067] A method for manufacturing the ATR prism 2 from a crystalline material will be described below. This method includes a preparation step of preparing a base material made of a crystalline material, and a processing step of processing this base material. The processing step includes, for example, a grinding step of grinding the base material, and a polishing step of polishing the base material after the grinding step. Without being limited thereto, the processing step may include an etching step of etching the base material.

[0068] According to the ATR prism 2 of the present invention described above, by forming the recess 10 of the second reflecting portion 6b on the second surface 2b and covering this recess 10 with the covering member 8, it is possible to prevent parts of the measuring device 1 on which the ATR prism 2 is mounted and foreign matter such as dust and the like from contacting the second total reflection surface provided on the bottom surface 12 of the recess 10. This makes it possible to prevent a decrease in the light detection accuracy (SN ratio) of the ATR prism 2.

[0069] 6 to 9 show a second embodiment of the present invention. The ATR prism 2 according to this embodiment includes, in addition to the entrance portion 5 and the exit portion 7, a first reflecting portion 6a, a second reflecting portion 6b, a third reflecting portion 6c, and a fourth reflecting portion 6d.

[0070] The entrance portion 5 and the exit portion 7 are provided on a part of an exposed surface 11 on the second surface 2b of the ATR prism 2. That is, in this embodiment, the entrance portion 5, the second reflecting portion 6b, and the exit portion 7 are provided on the same second surface 2b.

[0071] 6 to 8, the entrance portion 5 does not have the inclined surface 5a in the first embodiment, and is provided on a part of the exposed surface 11 at one end in the longitudinal direction of the second surface 2b. The exit portion 7 does not have the inclined surface 7a in the first embodiment, and is provided on a part of the exposed surface 11 at the other end in the longitudinal direction of the second surface 2b.

[0072] As in the first embodiment, the first reflecting portion 6a is provided on the entire first surface 2a of the ATR prism 2. As in the first embodiment, the second reflecting portion 6b is provided on the second surface 2b of the ATR prism 2.

[0073] The third reflecting portion 6c includes a reflecting surface that is inclined with respect to the first reflecting portion 6a and the second reflecting portion 6b. The inclination angle of this reflecting surface is set to be 45° or 60°, but is not limited to these angles. This reflecting surface (inclined surface) reflects the light introduced into the inside of the ATR prism 2 from the entrance portion 5 toward the first reflecting portion 6a.

[0074] The fourth reflecting portion 6d includes a reflecting surface (inclined surface) that is inclined with respect to the first reflecting portion 6a and the second reflecting portion 6b. The inclination angle of this reflecting surface is set to, but is not limited to, 45° or 60°. This reflecting surface (inclined surface) reflects the light that has been reflected (total reflected) multiple times between the first reflecting portion 6a and the second reflecting portion 6b toward the exit portion 7.

[0075] 6, the light introduced into the ATR prism 2 from the entrance 5 is reflected by the third reflecting portion 6c and travels toward the first reflecting portion 6a. Next, the light is reflected by the first reflecting portion 6a and travels toward the second reflecting portion 6b.

[0076] Thereafter, the light is repeatedly totally reflected between the first reflecting portion 6a and the second reflecting portion 6b. Next, the light is reflected by the first reflecting portion 6a and the fourth reflecting portion 6d, and then emitted from the emitting portion 7 and reaches the light receiving portion 4.

[0077] As shown in FIG. 9, in the method for manufacturing the ATR prism 2 of this embodiment, the entrance portion 5, the second reflecting portion 6b, and the exit portion 7 of the ATR prism 2 can be molded by the molding surface 16a of the first mold 16 in the molding process.

[0078] The molding surface 16a of the first molding die 16 includes an exposed surface molding portion 16b for molding the exposed surface 11 (including the incident portion 5 and the exit portion 7) of the second reflecting portion 6b, a bottom surface molding portion 16c for molding the bottom surface 12 of the second reflecting portion 6b, a first wall surface molding portion 16d for molding the first wall surfaces 13a-13d, a support surface molding portion 16e for molding the support surface 14, and a second wall surface molding portion 16f for molding the second wall surfaces 15a-15d.

[0079] In the molding step, the first reflecting portion 6a of the ATR prism 2 can be molded by the molding surface 17a of the second molding die 17. Furthermore, the third reflecting portion 6c and the fourth reflecting portion 6d of the ATR prism 2 can be molded by the molding surfaces 18a and 18b of the third molding die 18. Furthermore, the third molding die 18 can mold the side surface 9 of the ATR prism 2 by a molding surface (not shown) in the same manner as in the first embodiment.

[0080] Other configurations of this embodiment are the same as those of the first embodiment. In this embodiment, components common to the first embodiment are denoted by the same reference numerals.

[0081] 10 shows a third embodiment of the present invention. The ATR prism 2 according to this embodiment differs from the second embodiment in the configuration of the recess 10. The recess 10 of the ATR prism 2 includes only a bottom surface 12 and wall surfaces (first wall surfaces 13a-13d) surrounding the bottom surface 12, and does not include the support surface 14 and second wall surfaces 15a-15d in the first embodiment. A part of the covering member 8 is fixed to a part of the exposed surface 11. That is, the part of the exposed surface 11 functions as a support surface that supports the covering member 8.

[0082] Other configurations of this embodiment are the same as those of the second embodiment. In this embodiment, components common to both the second embodiment and the second embodiment are denoted by the same reference numerals.

[0083] 11 and 12 show a fourth embodiment of the present invention. The ATR prism 2 according to this embodiment differs from the second embodiment in the configuration of the recess 10.

[0084] In the second embodiment, the recess 10 of the ATR prism 2 includes four first walls 13a to 13d surrounding the entire circumference of the bottom surface 12, but the recess 10 according to this embodiment has only two first walls 13a, 13b formed to correspond to two opposing sides of the rectangular bottom surface 12. These two first walls 13a, 13b are configured to face each other. The two first walls 13a, 13b are configured to be parallel to the side surface 9 of the ATR prism 2, that is, to be elongated along the longitudinal direction of the ATR prism. The two first walls 13a, 13b corresponding to the two opposing sides of the bottom surface 12 do not have to be perpendicular to the bottom surface 12, and may be inclined at an angle θ4 with respect to the bottom surface 12 as shown in FIG. 12. If the value of this inclination angle θ4 is 60° or more and less than 90°, it becomes possible to easily release the glass molded body from the first molding die 16 (see the second embodiment) after the glass molded body is annealed and cooled in the above-mentioned molding step.

[0085] One side 12a of the rectangular bottom surface 12 of the recess 10 is exposed to the third reflecting portion 6c, and the other side 12b is exposed to the fourth reflecting portion 6d. That is, the bottom surface 12 of the recess 10 is configured in an elongated shape extending from the third reflecting portion 6c to the fourth reflecting portion 6d.

[0086] The length of the covering member 8 is shorter than the length of the bottom surface 12. With this configuration, the longitudinal end portion of the bottom surface 12 is exposed without being covered by the covering member 8. An entrance portion 5 and an exit portion 7 are set at this exposed end portion of the bottom surface 12.

[0087] In addition to the above configuration, the recess 10 includes two exposed surfaces 11, two second wall surfaces 15a, 15b formed to correspond to the first wall surfaces 13a, 13b, and two support surfaces 14 formed between the first wall surfaces 13a, 13b and the second wall surfaces 15a, 15b. The two second wall surfaces 15a, 15b corresponding to the two first wall surfaces 13a, 13b do not have to be perpendicular to the support surface 14, and may be inclined at an angle θ4 with respect to the support surface 14 as shown in FIG.

[0088] According to the ATR prism 2 of this embodiment, the bottom surface 12 is surrounded by only the two first walls 13a and 13b, so that a large distance can be secured between the two sides 12a and 12b of the bottom surface 12 where no first walls are formed. This makes it possible to secure a large area of ​​the second reflecting surface provided on the bottom surface 12, compared to the second embodiment.

[0089] Other configurations of this embodiment are the same as those of the second embodiment. In this embodiment, components common to both the second embodiment and the second embodiment are denoted by the same reference numerals.

[0090] 13 and 14 show a fifth embodiment of the present invention. The ATR prism 2 according to this embodiment differs from the second embodiment in the configuration of the recess 10.

[0091] In the second embodiment, the recess 10 includes four first walls 13a to 13d surrounding the bottom surface 12, but the recess 10 according to this embodiment has only two first walls 13a, 13b formed to correspond to two opposing sides of the rectangular bottom surface 12. These two first walls 13a, 13b are configured to face each other. Of the two first walls 13a, 13b, one first wall 13a is located closer to the third reflecting portion 6c, and the other first wall 13b is located closer to the fourth reflecting portion 6d. The two first walls 13a, 13b are configured to be elongated along the width direction (direction along the symbol W) of the ATR prism 2. The two first walls 13a, 13b corresponding to the opposing two sides of the bottom surface 12 do not have to be perpendicular to the bottom surface 12, and may be inclined at an angle θ5 with respect to the bottom surface 12 as shown in FIG. 14. If the value of this inclination angle θ5 is greater than or equal to 60° and less than 90°, the glass molded body can be easily released from the first mold 16 (see the second embodiment) after being slowly cooled in the above-mentioned molding process.

[0092] Of the four sides of the rectangular bottom surface 12 of the recess 10, one side 12a is exposed to one side surface 9 of the ATR prism 2, and the other side 12b is exposed to the other side surface 9. This allows the ATR prism 2 to have a larger area for the bottom surface 12 (second reflecting surface) than in the second embodiment.

[0093] In addition to the above configuration, the recess 10 includes two exposed surfaces 11, two second wall surfaces 15a, 15b formed to correspond to the first wall surfaces 13a, 13b, and two support surfaces 14 formed between the first wall surfaces 13a, 13b and the second wall surfaces 15a, 15b. The two second wall surfaces 15a, 15b corresponding to the two first wall surfaces 13a, 13b do not have to be perpendicular to the support surface 14, and may be inclined at an angle θ5 with respect to the support surface 14 as shown in FIG.

[0094] Other configurations of this embodiment are the same as those of the second embodiment. In this embodiment, components common to both the second embodiment and the second embodiment are denoted by the same reference numerals.

[0095] The present invention is not limited to the configuration of the above embodiment, nor is it limited to the above-mentioned effects and advantages. Various modifications of the present invention are possible without departing from the spirit and scope of the present invention.

[0096] In the above second to fifth embodiments, the ATR prism 2 in which the entrance portion 5 and the exit portion 7 are integrally formed with the second reflecting portion 6b have been exemplified, but the present invention is not limited to this embodiment. The entrance portion 5 or the exit portion 7 may be integrally formed with another reflecting portion.

[0097] An anti-reflection film may be provided on each surface of the entrance portion 5 and the exit portion 7 in the above embodiment.

[0098] In the above embodiment, the ATR prism 2 in which the recess 10 is covered with the covering member 8 has been exemplified, but the present invention is not limited to this configuration. The ATR prism 2 may be incorporated into the measurement device 1 without including the covering member 8. When the ATR prism 2 in the measurement device 1 is supported by a supporting member, for example, the supporting member may be brought into contact with a part of the exposed surface of the second surface 2b (a portion excluding the reflecting surface).

[0099] The recess 10 of the ATR prism 2 exemplified in the fourth and fifth embodiments may be formed in the ATR prism 2 according to the first embodiment.

[0100] In the above embodiment, the ATR prism 2 in which the recess 10 is formed on the second surface 2b is exemplified, but the present invention is not limited to this configuration. The recess 10 may be formed on the first surface 2a. In this case, the second surface 2b becomes a contact surface that comes into contact with the sample S, and the first surface 2a becomes a non-contact surface that does not come into contact with the sample S. [Explanation of symbols]

[0101] 1. Measuring equipment 2 ATR Prism 2a First surface 2b Second surface 3 light source 4 Light receiving section 5 Input part 5a Slope 6a First reflection part (first total reflection surface) 6b Second reflection section 6c Third reflection section 6d Fourth reflection section 7. Output section 7a Slope 8 Covering material 9. Side 10 Recess 11 Exposed surface 12 Bottom surface of the recess (second total reflection surface) 12a One side 12b The other side 13a First wall of recess 13b First wall of recess 13c First wall of recess 13d First wall of recess 14 Support surface 15a Second wall 15b Second wall 15c Second wall 15d Second wall 16 First mold 16a Molding surface 17 Second mold 17a Molding surface 17b Exposed surface molding part 17c Bottom molding part 17d First wall molding section 17e Support surface molding part 17f Second wall molding section 18 Third mold 18a Molding surface 18b Molding surface 19 Fourth mold 19a First cylinder part 19b Second cylinder part 20 Base glass S Sample (measurement object) T thickness dimension W Width dimension T1 Thickness D Depth D1 Separation distance L1 Length dimension L2 Length dimension L3 Length dimension W Width dimension W1 Width dimension θ1 Tilt angle θ2 Tilt angle θ3 Tilt angle θ4 Tilt angle θ5 Tilt angle

Claims

1. An ATR prism made of a material having an internal transmittance of 90% or more in a wavelength range of 8 to 10 μm at a thickness of 2 mm, a first surface including a first total internal reflection surface; a second surface including a second totally reflective surface; a recess formed in the first surface or the second surface, The first surface is a contact surface that comes into contact with a measurement object, The second surface is a non-contact surface that does not contact the measurement object, the recess is formed in the second surface; The recess has a bottom surface, the bottom surface includes the second total reflection surface, The ATR prism includes a covering member that covers the recess at a position spaced from the bottom surface.

2. 2. The ATR prism of claim 1, wherein the material is glass.

3. 3. The ATR prism according to claim 2, wherein the glass is a chalcogenide glass.

4. The ATR prism according to claim 3, wherein the chalcogenide glass contains, in mole percentages, 50 to 80% S, 0 to 40% Sb (but not including 0%), 0 to 18% Ge (but not including 0%), 0 to 20% Sn, and 0 to 20% Bi.

5. 4. The ATR prism according to claim 3, wherein the chalcogenide glass contains, by mole percentage, 4 to 80% Te, 0 to 50% (but not including 0%) Ge, and 0 to 20% Ga.

6. 2. The ATR prism according to claim 1, wherein the distance between the bottom surface of the recess and the covering member is 0.1 to 3.0 mm.

7. The ATR prism according to claim 1 or 6, wherein the recess has a wall surface surrounding the entire periphery of the bottom surface.

8. The bottom surface of the recess is configured in a rectangular shape having four sides, The recess has a wall surface surrounding the bottom surface, 7. The ATR prism according to claim 1, wherein the wall surface includes only two wall surfaces corresponding to two opposing sides of the bottom surface.

9. 9. The ATR prism according to claim 1, wherein the distance between the bottom surface of the recess and the first surface is 0.1 to 3.0 mm.

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