ATR prism and method for manufacturing the ATR prism

Abstract

To provide an ATR prism which can be produced with high productivity and offers high shape accuracy of an incident surface, total reflection surfaces, and an exit surface.SOLUTION: An ATR prism provided herein is made of glass having an internal transmittance of 90% or greater in a wavelength range of 8-10 μm at a thickness of 2 mm.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an ATR prism and a method for manufacturing the ATR prism.

Background Art

[0002] As a method for non-invasively obtaining biological information such as blood glucose level, the ATR (Attenuated Total Reflection) method is known. In the ATR method, when total reflection occurs in an ATR prism disposed in contact with the object to be measured, the absorption spectrum of the object to be measured is obtained by using the evanescent wave oozing out from the total reflection surface.

[0003] For example, the ATR prism disclosed in Patent Document 1 includes an incident surface, a first total reflection surface, a second total reflection surface, and an exit surface. In this ATR prism, with the first total reflection surface in contact with the living body, the probe light incident from the incident surface is repeatedly totally reflected between the first total reflection surface and the second total reflection surface. Then, the probe light exits from the exit surface and is converted into a detection signal by a photodetector (see paragraphs 0039 to 0041 of Patent Document 1).

[0004] This ATR prism is manufactured from a crystalline material such as zinc sulfide (ZnS), zinc selenide (ZnSe), germanium, or silicon (see paragraph 0050 of Patent Document 1 and page 9 of Patent Document 2, for example).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] Since conventional ATR prisms are composed of crystals, it was necessary to perform polishing and etching processes to form the incident surface, each total reflection surface, and the exit surface. For this reason, the production of ATR prisms was time-consuming, and there was a demand for improvement in the optical detection accuracy due to the low shape accuracy of the incident surface, each total reflection surface, and the exit surface of the ATR prism. Here, the shape accuracy refers to the surface roughness, angular accuracy, and shape reproducibility of these surfaces during production of the incident surface, each total reflection surface, and the exit surface of the ATR prism, and the optical detection accuracy refers to the signal-to-noise ratio (SN ratio) of the optical component extracted from the exit surface of the ATR prism.

[0007] The present invention has been made in view of the above circumstances, and an object thereof is to provide an ATR prism with high productivity and high shape accuracy of the incident surface, each total reflection surface, and the exit surface.

Means for Solving the Problems

[0008] The ATR prism according to the present invention is for solving the above problems, and is composed of glass having an internal transmittance of 90% or more in a wavelength range of 8 to 10 μm at a wall thickness of 2 mm. If the ATR prism is composed of glass, the ATR prism can be easily formed by mold molding without using a conventional polishing process or etching process. Thereby, it becomes possible to improve the productivity of the ATR prism. Further, by increasing the shape accuracy of the incident surface, each total reflection surface, and the exit surface of the ATR prism by mold molding, it becomes possible to improve the optical detection accuracy.

[0009] The glass constituting the ATR prism may be chalcogenide glass. The chalcogenide glass may contain, in mole percentage, S 50 to 80%, Sb 0 to 40% (excluding 0%), Ge 0 to 18% (excluding 0%), Sn 0 to 20%, and Bi 0 to 20%. Alternatively, the chalcogenide glass may contain, in mole percentage, Te 4 to 80%, Ge 0 to 50% (excluding 0%), and Ga 0 to 20%.

[0010] The ATR prism according to the present invention may include an incident portion where light in the wavelength range is incident, an exit portion that emits the light, and a lens portion integrally formed with at least one of the incident portion and the exit portion.

[0011] According to such a configuration, by adjusting the angle of the light introduced into the ATR prism with the lens portion, the signal-to-noise ratio of the ATR prism can be improved, and it becomes possible to accurately measure biological information.

[0012] The ATR prism according to the present invention includes a reflection portion that reflects the light, the incident portion has an inclined surface that is inclined with respect to the reflection portion, and the lens portion may be formed on the inclined surface of the incident portion.

[0013] Further, in the ATR prism according to the present invention, a reflection portion that reflects the light is provided, the exit portion has an inclined surface that is inclined with respect to the reflection portion, and the lens portion may be formed on the inclined surface of the exit portion.

[0014] Further, in the ATR prism according to the present invention, a reflection portion that reflects the light is provided, and the incident portion may be configured integrally with the reflection portion.

[0015] Further, in the ATR prism according to the present invention, a reflection portion that reflects the light is provided, and the exit portion may be configured integrally with the reflection portion.

[0016] The reflection portion has a reflection surface that reflects the light, and the lens portion may be provided in a concave portion formed on the reflection surface so as not to protrude from the reflection surface.

[0017] The incident portion has the lens portion, and the concave portion may include a positioning portion for positioning a light source for irradiating the incident portion with the light. According to such a configuration, it becomes possible to efficiently perform the work when attaching the light source to the ATR prism.

[0018] The light emitting unit may include the lens unit, and the concave portion may include a positioning unit for positioning a light receiving unit that receives the light emitted from the light emitting unit. According to such a configuration, it is possible to efficiently perform the work when attaching the light receiving unit to the ATR prism.

[0019] The manufacturing method of the ATR prism according to the present invention is for solving the above problems, and includes a molding step of molding the ATR prism by pressing a base glass with a molding die while heating the base glass.

[0020] According to such a configuration, the above ATR prism can be easily molded from the base glass in the molding step. According to this method, since there is no need to go through a polishing step or an etching treatment step as in the prior art, the productivity of the ATR prism can be increased, and by improving the shape accuracy of the incident surface, each total reflection surface, and the light emitting surface of the ATR prism, the light detection accuracy can be improved.

Effect of the Invention

[0021] According to the present invention, it is possible to provide an ATR prism with high productivity and high shape accuracy of the incident surface, each total reflection surface, and the light emitting surface.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0023] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. FIGS. 1 to 4 show an ATR prism according to a first embodiment, a measuring device including the ATR prism, and a method for manufacturing the ATR prism.

[0024] As shown in FIG. 1, the measuring device 1 mainly includes an ATR prism 2, a light source 3, and a light receiving unit 4. As shown in FIGS. 1 and 2, the ATR prism 2 includes an incident portion 5 where light from the light source 3 is incident, a reflection portion 6 that reflects the incident light, an exit portion 7 that emits the light reflected by the reflection portion 6, and a side surface 8 formed between the incident portion 5 and the exit portion 7.

[0025] The incident portion 5 includes an inclined surface 5a that is inclined with respect to the reflection portion 6 and a lens portion 5b that is integrally formed with the inclined surface 5a. As the inclination angle θ1 of the inclined surface 5a, for example, 45° or 60° is adopted, but it is not limited to these angles and can be appropriately set according to the shape and dimensions of the ATR prism 2.

[0026] The lens portion 5b is configured in a convex shape protruding from the inclined surface 5a, but is not limited to this shape. The lens portion 5b can adjust the incident angle of the light irradiated from the light source 3 and introduce it into the ATR prism 2. In the present embodiment, an ATR prism 2 in which one lens portion 5b is formed in the incident portion 5 is exemplified, but the number of lens portions 5b is not limited to the present embodiment. A plurality of lens portions 5b may be formed in the incident portion 5 at intervals in the width direction of the ATR prism 2 (the direction indicated by reference numeral W in FIG. 2).

[0027] The reflection portion 6 includes a first reflection portion 6a and a second reflection portion 6b. As shown in FIG. 2, the length dimension L1 of the first reflection portion 6a is larger than the length dimension L2 of the second reflection portion 6b. The first reflection portion 6a and the second reflection portion 6b include a reflection surface (total reflection surface) that reflects the light introduced into the ATR prism 2 from the incident portion 5. The reflection surface of the first reflection portion 6a is a contact surface that contacts the biological sample (hereinafter simply referred to as "sample") S to be measured. The reflection surface of the second reflection portion 6b is a non-contact surface that does not contact the sample S.

[0028] The exit portion 7 has an inclined surface 7a that is inclined with respect to the reflection portion 6 and a lens portion 7b that is integrally formed with the inclined surface 7a. As the inclination angle θ2 of the inclined surface 7a, for example, 45° or 60° is adopted, but it is not limited to these angles and can be appropriately set according to the shape and dimensions of the ATR prism 2.

[0029] The lens portion 7b is configured in a convex shape protruding from the inclined surface 7a, but is not limited to this shape. The lens portion 7b adjusts the angle of the light reflected by the reflection portion 6 and emits it toward the light receiving portion 4. In the present embodiment, an ATR prism 2 in which one lens portion 7b is formed in the exit portion 7 is exemplified, but the number of lens portions 7b is not limited to the present embodiment. A plurality of lens portions 7b may be formed in the exit portion 7 at intervals in the width direction of the ATR prism 2.

[0030] The side surface 8 separates the incident portion 5 and the exit portion 7 in the longitudinal direction of the ATR prism 2 (the direction indicated by reference numerals L1 or L2 in FIG. 2). Further, the side surface 8 separates the first reflecting portion 6a and the second reflecting portion 6b in the thickness direction of the ATR prism 2 (the direction indicated by reference numeral T in FIG. 2). The angle formed by the side surface 8 and the reflecting surface of the reflecting portion 6 is 90°, but this angle is not limited to this embodiment.

[0031] The width dimension W of the ATR prism 2 is, for example, 2 to 15 mm, preferably 3 to 12 mm. The thickness dimension T of the ATR prism 2 is, for example, 1 to 10 mm, preferably 2 to 8 mm. The length dimension L1 of the first reflecting portion 6a of the ATR prism 2 is, for example, 5 to 30 mm, preferably 7 to 27 mm. The length dimension L2 of the second reflecting portion 6b of the ATR prism 2 is, for example, 3 to 20 mm, preferably 5 to 17 mm.

[0032] The ATR prism 2 is made of, for example, glass having an internal transmittance of 90% or more, preferably 91% or more, more preferably 92% or more in a wavelength range of 8 to 10 μm at a wall thickness of 2 mm. The glass may be, for example, chalcogenide glass. The chalcogenide glass may contain, in mole percentage, 50 to 80% of S, 0 to 40% of Sb (excluding 0%), 0 to 18% of Ge (excluding 0%), 0 to 20% of Sn, and 0 to 20% of Bi.

[0033] In the above chalcogenide glass, the content of S is, in mole percentage, more preferably 55% or more, still more preferably 60% or more, more preferably 75% or less, still more preferably 70% or less. When the content of S in the glass is less than 50%, it becomes difficult to vitrify. On the other hand, when the content of S in the glass exceeds 80%, the weather resistance of the glass deteriorates, and thus the usage environment of the ATR prism is restricted.

[0034] In the above chalcogenide glass, the content of Sb is more preferably 5% or more, still more preferably 10% or more, more preferably 35% or less, and still more preferably 33% or less in terms of mole percentage. When Sb is not contained in the glass or the content thereof exceeds 40%, it becomes difficult to vitrify.

[0035] In the above chalcogenide glass, the content of Ge is more preferably 2% or more, still more preferably 4% or more, more preferably 20% or less, and still more preferably 15% or less in terms of mole percentage. When Ge is not contained in the glass, it becomes difficult to vitrify. On the other hand, when the content of Ge in the glass exceeds 18%, it becomes difficult to obtain an internal transmittance that satisfies the characteristics of the ATR prism due to the precipitation of Ge-based crystals from the glass.

[0036] In the above chalcogenide glass, the content of Sn is more preferably 1% or more, still more preferably 5% or more, more preferably 15% or less, and still more preferably 10% or less in terms of mole percentage. Sn in the glass is a component that promotes vitrification. However, when the content of Sn in the glass exceeds 20%, it becomes difficult to vitrify.

[0037] In the above chalcogenide glass, the content of Bi is more preferably 0.5% or more, still more preferably 2% or more, more preferably 10% or less, and still more preferably 8% or less in terms of mole percentage. Bi in the glass is a component that suppresses the energy required for the raw materials to vitrify during melting of the glass. On the other hand, when the content of Bi in the glass exceeds 20%, it becomes difficult to obtain an internal transmittance that satisfies the characteristics of the ATR prism due to the precipitation of Bi-based crystals from the glass.

[0038] Not limited to the above composition, the chalcogenide glass may contain Te 4 to 80%, Ge 0 to 50% (excluding 0%), and Ga 0 to 20% in terms of mole percentage.

[0039] In the above chalcogenide glass, the content of Te is more preferably 10% or more, still more preferably 20% or more, more preferably 75% or less, and still more preferably 70% or less in terms of mole percentage. When the content of Te in the glass is less than 4%, it becomes difficult to vitrify. On the other hand, when the content of Te in the glass exceeds 80%, Te-based crystals precipitate from the glass, making it difficult to obtain an internal transmittance that satisfies the characteristics of the ATR prism.

[0040] In the above chalcogenide glass, the content of Ge is more preferably 1% or more, still more preferably 5% or more, more preferably 40% or less, and still more preferably 30% or less in terms of mole percentage. When Ge is not contained in the glass, it becomes difficult to vitrify. On the other hand, when the content of Ge in the glass exceeds 50%, Ge-based crystals precipitate from the glass, making it difficult to obtain an internal transmittance that satisfies the characteristics of the ATR prism.

[0041] In the above chalcogenide glass, the content of Ga is more preferably 0.1% or more, still more preferably 1% or more, more preferably 15% or less, and still more preferably 10% or less in terms of mole percentage. By containing Ga in the glass, the vitrification range can be widened and the thermal stability (stability of vitrification) of the glass can be enhanced.

[0042] Also, in order to enable confirmation of the processing quality, internal quality, etc. of the ATR prism by an optical device using near-infrared light, the above glass preferably has an internal transmittance of 10% or more, more preferably 30% or more, and still more preferably 50% or more in the wavelength band of 1 to 2 μm at a thickness of 2 mm. Thereby, it becomes possible to apply a high-quality ATR prism.

[0043] As shown in FIG. 1, the light source 3 is disposed in the vicinity of the incident portion 5 of the ATR prism 2 so as to face the lens portion 5b of the incident portion 5. The light source 3 is configured to irradiate the incident portion 5 of the ATR prism 2 with, for example, infrared light. The light source 3 is constituted by, for example, a device including a quantum cascade laser that emits laser light in the infrared region, but is not limited to this embodiment. Here, the infrared light refers to light having a wavelength range of 8 to 10 μm.

[0044] As shown in FIG. 1, the light receiving portion 4 is disposed in the vicinity of the emitting portion 7 so as to face the lens portion 7b of the emitting portion 7.

[0045] Hereinafter, a method for measuring biological information by the measuring device 1 will be described. The light (infrared light) emitted from the light source 3 is adjusted by the lens portion 5b of the incident portion 5 and introduced into the ATR prism 2. This light propagates to the lens portion 7b of the emitting portion 7 while repeating reflection (total reflection) between the first reflecting portion 6a and the second reflecting portion 6b.

[0046] When the sample S is in contact with the first reflecting portion 6a, the light is totally reflected at the contact surface between the first reflecting portion 6a of the ATR prism 2 and the sample S without exiting from the ATR prism 2. In this case, the light leaks out (evanescent wave) to the sample S side by a slight distance, and if there is light absorption 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 object contained in the sample S can be obtained. Since there is a correlation between the infrared absorption spectrum measured based on the light that has exited from the emitting portion 7 and reached the light receiving portion 4 and the internal state of the sample S, it is possible to acquire biological information such as blood glucose level contained in the sample S based on this infrared absorption spectrum.

[0047] Hereinafter, a method for manufacturing the ATR prism 2 having the above configuration will be described. This method includes a preparation step of preparing a base glass and a molding step of molding the ATR prism 2 from the base glass.

[0048] In the preparation process, for example, a base glass is prepared, where the glass composition is a chalcogenide glass with S 60%, Sb 30%, Ge 5%, and Sn 5% in mole percentage, or the glass composition is a chalcogenide glass with Te 70%, Ge 25%, and Ga 5% in mole percentage. As shown in Figure 3, the base glass 13 is configured in a rectangular parallelepiped shape, but is not limited to this shape. In the preparation process, polishing (mirror finishing) may be performed on the entire surface or a part of the surface of the base glass 13.

[0049] In the forming process, the ATR prism 2 is formed by pressing the base glass 13 with a forming die while heating it. As shown in Figures 3 and 4, the forming dies 9 to 12 used in the forming process include a first forming die 9, a second forming die 10, a third forming die 11, and a fourth forming die 12. The forming dies 9 to 12 are composed of a metal such as cemented carbide, for example.

[0050] The forming dies 9 to 12 are preferably arranged in a metal chamber filled with an inert gas (for example, nitrogen gas). Outside the chamber, heaters are provided for heating the forming dies 9 to 12 and the base glass 13.

[0051] The first forming die 9 is located above the second forming die 10. The first forming die 9 has a forming surface 9a for forming the first reflection portion 6a of the ATR prism 2. The second forming die 10 has a forming surface 10a for forming the second reflection portion 6b of the ATR prism 2.

[0052] The third forming die 11 is configured in a cylindrical shape such that a part of the second forming die 10 is inserted inside. The third forming die 11 includes a forming surface 11a for forming the inclined surface 5a and the lens portion 5b of the incident portion 5 of the ATR prism 2, and a forming surface 11b for forming the inclined surface 7a and the lens portion 7b of the exit portion 7. In addition, the third forming die 11 includes a forming surface (not shown) for forming the side surface 8 of the ATR prism 2.

[0053] The fourth molding die 12 is configured in a cylindrical shape and includes a first cylindrical portion 12a through which a part of the first molding die 9 is inserted and a second cylindrical portion 12b through which the third molding die 11 is inserted. The first cylindrical portion 12a of the fourth molding die 12 functions as a guide portion for moving the first molding die 9 in the vertical direction with a part of the first molding die 9 inserted therethrough.

[0054] In the molding process, the base glass 13 is placed on the molding surface 10a of the second molding die 10. Next, the first molding die 9 inserted through the first cylindrical portion 12a of the fourth molding die 12 is lowered to approach the second molding die 10. Then, with the molding dies 9 to 12 and the base glass 13 heated by a heater, the base glass 13 is pressed by the first molding die 9 and the second molding die 10.

[0055] In the molding process, the base glass 13 is heated to, for example, 160 to 260°C. The heated base glass 13 softens and deforms under the pressure applied from the first molding die 9. The molding surfaces (including the molding surfaces not shown) 9a, 10a, 11a, 11b of the first molding die 9 to the third molding die 11 come into contact with the softened base glass 13 to form the incident portion 5, the reflection portion 6, the exit portion 7, and the side surface 8 of the ATR prism 2. Then, the first molding die 9 and the second molding die 10 are cooled, and the glass molded body is gradually cooled and cooled, whereby the ATR prism 2 is completed.

[0056] According to the ATR prism 2 and its manufacturing method according to the present invention described above, the ATR prism 2 can be easily manufactured from the base glass 13 by mold molding without using a polishing process or an etching process as in the prior art. Thereby, the productivity of the ATR prism 2 can be increased, and the optical detection accuracy can be improved by enhancing the shape accuracy of the lens portion 5b which is the incident surface of the incident portion 5 of the ATR prism 2, each total reflection surface of the reflection portion 6, and the lens portion 7b which is the exit surface of the exit portion 7 of the ATR prism 2. Note that the present invention does not exclude performing polishing or etching processes in order to adjust the final shape accuracy of the ATR prism 2 after mold molding.

[0057] Figures 5 and 6 show a second embodiment of the present invention. The ATR prism 2 has a first reflecting portion 6a that contacts the sample S and a second reflecting portion 6b that faces the first reflecting portion 6a and does not contact the sample S. In the ATR prism 2 according to the present embodiment, the length dimension L1 of the first reflecting portion 6a is smaller than the length dimension L2 of the second reflecting portion 6b.

[0058] The incident portion 5 and the exit portion 7 are integrally formed with respect to the reflecting surface of the second reflecting portion 6b. As shown in FIG. 5, the incident portion 5 does not have the inclined surface 5a in the first embodiment and has only the lens portion 5b. This lens portion 5b is integrally formed at one end in the longitudinal direction of the reflecting surface of the second reflecting portion 6b. The exit portion 7 does not have the inclined surface 7a in the first embodiment and has only the lens portion 7b. This lens portion 7b is integrally formed at the other end in the longitudinal direction of the reflecting surface of the second reflecting portion 6b.

[0059] In addition to the first reflecting portion 6a and the second reflecting portion 6b described above, the ATR prism 2 includes a third reflecting portion 6c and a fourth reflecting portion 6d that connect the first reflecting portion 6a and the second reflecting portion 6b.

[0060] 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 45° or 60°, but is not limited to these angles. This reflecting surface (inclined surface) reflects the light introduced into the ATR prism 2 from the incident portion 5 toward the first reflecting portion 6a.

[0061] 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 45° or 60°, but is not limited to these angles. This reflecting surface (inclined surface) reflects the light that has been reflected (total reflected) a plurality of times between the first reflecting portion 6a and the second reflecting portion 6b toward the lens portion 7b of the exit portion 7.

[0062] As shown in FIG. 6, in the method for manufacturing the ATR prism 2 according to the present embodiment, in the molding step, the molding surface 9a of the first mold 9 can mold the reflection surface of the second reflection portion 6b of the ATR prism 2 and the lens portions 5b and 7b of the incident portion 5 and the exit portion 7. Further, the first reflection portion 6a of the ATR prism 2 can be molded by the molding surface 10a of the second mold 10. Furthermore, the third reflection portion 6c and the fourth reflection portion 6d of the ATR prism 2 can be molded by the molding surfaces 11a and 11b of the third mold 11. Similar to the first embodiment, the third mold 11 can mold the side surface 8 of the ATR prism 2 by a molding surface (not shown).

[0063] Other configurations in the present embodiment are the same as those in the first embodiment. Components common to the first embodiment in the present embodiment are given common reference numerals.

[0064] FIGS. 7 to 10 show a third embodiment of the present invention. The ATR prism 2 according to the present embodiment differs from the second embodiment in the configurations of the incident portion 5 and the exit portion 7. The lens portion 5b of the incident portion 5 is provided in a first concave portion 14 formed at one end in the longitudinal direction of the reflection surface so as not to protrude from the reflection surface of the second reflection portion 6b. The exit portion 7 is provided in a second concave portion 15 formed at the other end in the longitudinal direction of the reflection surface so as not to protrude from the reflection surface of the second reflection portion 6b.

[0065] As shown in FIG. 7, each of the concave portions 14 and 15 has convex lens portions 5b and 7b at their central positions. As shown in FIG. 8, annular groove portions (first groove portion 16 and second groove portion 17) are formed around the lens portions 5b and 7b in each of the concave portions 14 and 15.

[0066] As shown in FIGS. 7 and 9, the measuring device 1 according to the present embodiment includes a holding member 18 that holds the light source 3 and the light receiving portion 4. The holding member 18 has a first hole 18a that holds the light source 3 and a second hole 18b that holds the light receiving portion 4.

[0067] The light source 3 is composed of an optical fiber, and includes a core 19 for light irradiation and a coating member (protective member) 20 that coats the core 19. The coating member 20 is configured, for example, in a cylindrical shape so as to coat the entire circumference of the core 19. The end of the coating member 20 protrudes from the end of the core 19.

[0068] The light receiving part 4 is composed of an optical fiber, and includes a core 21 for light reception and a coating member (protective member) 22 that coats the core 21. The coating member 22 is configured, for example, in a cylindrical shape so as to coat the entire circumference of the core 21. The end of the coating member 22 protrudes from the end of the core 21.

[0069] Hereinafter, a method for attaching the light source 3 and the light receiving part 4 to the ATR prism 2 will be described.

[0070] As shown in FIG. 10, a holding member 18 located at a position away from the ATR prism 2 is brought closer to the ATR prism 2, and the end of the light source 3 (the end of the coating member 20) is fitted into the first groove portion 16 of the first concave portion 14 of the ATR prism 2. Further, the end of the light receiving part 4 (the end of the coating member 22) is fitted into the second groove portion 17 of the second concave portion 15 of the ATR prism 2 (see FIG. 7).

[0071] Thus, the first groove portion 16 of the first concave portion 14 provided with the incident portion 5 functions as a positioning portion for positioning the light source 3 with respect to the incident portion 5. Further, the second groove portion 17 of the second concave portion 15 provided with the exit portion 7 functions as a positioning portion for positioning the light receiving part 4 with respect to the exit portion 7. In the measuring device 1 according to the present embodiment, by simply bringing the holding member 18 closer to the ATR prism 2, the positioning (centering) of the light source 3 and the light receiving part 4 with respect to the ATR prism 2 can be easily performed by the respective groove portions 16 and 17.

[0072] Other configurations in the present embodiment are the same as those in the second embodiment. Components common to the second embodiment in the present embodiment are denoted by common reference numerals.

[0073] FIG. 11 shows a fourth embodiment of the present invention. In this embodiment, the shape of the ATR prism is different from that of the third embodiment.

[0074] The ATR prism 2 has a recess 23 in which the third reflecting portion 6c is formed and a recess 24 in which the fourth reflecting portion 6d is formed. The third reflecting portion 6c is formed on the side surface (inclined surface) of the recess 23. The fourth reflecting portion 6d is formed on the side surface (inclined surface) of the recess 24.

[0075] The first recess 14 in which the incident portion 5 is formed has, in addition to the annular first groove portion 16, a first side wall portion 25 through which a part of the light source 3 is inserted. The first side wall portion 25 has an insertion port 25a for inserting the light source 3. The first side wall portion 25 is a guide hole for guiding the light source 3 from the insertion port 25a to the first groove portion 16. The first side wall portion 25 also functions as a holding portion for holding the outer peripheral surface of the covering member 20 of the light source 3 to be inserted.

[0076] The second recess 15 in which the exit portion 7 is formed has, in addition to the annular second groove portion 17, a second side wall portion 26 through which a part of the light receiving portion 4 is inserted. The second side wall portion 26 has an insertion port 26a for inserting the light receiving portion 4. The second side wall portion 26 is a guide hole for guiding the light receiving portion 4 from the insertion port 26a to the second groove portion 17. The second side wall portion 26 also functions as a holding portion for holding the outer peripheral surface of the covering member 22 of the light receiving portion 4 to be inserted.

[0077] According to this embodiment, the ATR prism 2 can easily position and hold the light source 3 and the light receiving portion 4 by the groove portions 16 and 17 and the side wall portions 25 and 26 of the respective recesses 14 and 15.

[0078] Other configurations in this embodiment are the same as those in the third embodiment. Components common to the third embodiment in this embodiment are given the same reference numerals.

[0079] Note that the present invention is not limited to the configurations of the above embodiments, nor is it limited to the above-described effects. The present invention can be variously modified without departing from the gist of the present invention.

[0080] In the above-described embodiment, the ATR prism 2 in which the lens portions 5b and 7b are formed in the incident portion 5 and the exit portion 7 has been exemplified. However, the present invention is not limited to this configuration. The lens portion may be formed on one of the incident portion 5 and the exit portion 7. The lens portion may not be formed in the incident portion 5 and the exit portion 7.

[0081] In the above-described embodiment, the ATR prism 2 in which the incident portion 5 and the exit portion 7 are integrally formed with the second reflection portion 6b has been exemplified. However, the present invention is not limited to this aspect. The incident portion 5 or the exit portion 7 may be formed on another reflection portion.

[0082] In the above-described embodiment, the ATR prism 2 in which the light source 3 and the light receiving portion 4 can be directly attached to the side wall portions 25 and 26 of the respective concave portions 14 and 15 has been exemplified. However, the present invention is not limited to this configuration. For example, an adapter to which the light source 3 and the light receiving portion 4 can be detachably attached may be attached to the side wall portions 25 and 26 of the respective concave portions 14 and 15. Thereby, the light source 3 and the light receiving portion 4 can be detachably attached to the ATR prism 2 (adapter).

Explanation of Reference Numerals

[0083] 1 Measuring device 2 ATR prism 3 Light source 4 Light receiving portion 5 Incident portion 5a Inclined surface of the incident portion 5b Lens portion of the incident portion 6a First reflection portion 6b Second reflection portion 6c Third reflection portion 6d Fourth reflection portion 7 Exit portion 7a Inclined surface of the exit portion 7b Lens portion of the exit portion 8 Side surface 9 First mold 9a Molding surface of the first mold 10 Second mold 10a Molding surface of the second mold 11 Third forming mold 11a Forming surface of the third forming mold 11b Forming surface of the third forming mold 12 Fourth forming mold 12a First cylindrical part of the fourth forming mold 12b Second cylindrical part of the fourth forming mold 13 Base glass 14 First recess 15 Second recess 16 First groove part (positioning part) 17 Second groove part (positioning part) 18 Holding member 18a First hole for holding the light source 3 18b Second hole for holding the light receiving part 4 19 Core for light irradiation 20 Coating member 21 Core for light reception 22 Coating member (protective member) 23 Recess where the third reflecting part 6c is formed 24 Recess where the fourth reflecting part 6d is formed 25 First side wall part 25a Insertion port 26 Second side wall part 26a Insertion port L1 Length dimension of the first reflecting part 6a L2 Length dimension of the second reflecting part 6b S Biological sample (sample) W Width direction of the ATR prism 2 T Thickness direction of the ATR prism 2

Claims

1. An ATR prism composed of glass with an internal transmittance of 90% or more in the wavelength range of 8 to 10 μm at a thickness of 2 mm, comprising an incident portion where light in the wavelength range is incident, a reflection portion that reflects the light, and an exit portion that emits the light, wherein the incident portion is integrally formed with the reflection portion, the reflection portion has a reflection surface that reflects the light, the incident portion includes a lens portion formed on the reflection surface, and the lens portion of the incident portion is provided in a concave portion formed on the reflection surface so as not to protrude from the reflection surface.

2. An ATR prism composed of glass with an internal transmittance of 90% or more in the wavelength range of 8 to 10 μm at a thickness of 2 mm, comprising an incident portion where light in the wavelength range is incident, a reflection portion that reflects the light, and an exit portion that emits the light, wherein the exit portion is integrally formed with the reflection portion, the reflection portion has a reflection surface that reflects the light, the exit portion includes a lens portion formed on the reflection surface, and the lens portion of the exit portion is provided in a concave portion formed on the reflection surface so as not to protrude from the reflection surface.

3. An ATR prism composed of glass with an internal transmittance of 90% or more in the wavelength range of 8 to 10 μm at a thickness of 2 mm, comprising an incident portion where light in the wavelength range is incident, a reflection portion that reflects the light, and an exit portion that emits the light, wherein the incident portion and the exit portion are integrally formed with the reflection portion, the reflection portion has a reflection surface that reflects the light, the incident portion includes a lens portion formed on the reflection surface, the exit portion includes a lens portion formed on the reflection surface, the lens portion of the incident portion is provided in a first concave portion formed on the reflection surface so as not to protrude from the reflection surface, and the lens portion of the exit portion is provided in a second concave portion formed on the reflection surface so as not to protrude from the reflection surface.

4. The ATR prism according to any one of claims 1 to 3, wherein the glass is chalcogenide glass.

5. The ATR prism according to claim 4, wherein the chalcogenide glass contains, in mole percentage, 50 to 80% of S, 0 to 40% of Sb (excluding 0%), 0 to 18% of Ge (excluding 0%), 0 to 20% of Sn, and 0 to 20% of Bi.

6. The chalcogenide glass contains, in mole percentage, 4 to 80% of Te, 0 to 50% (excluding 0%) of Ge, and 0 to 20% of Ga, and the ATR prism according to claim 4.

7. The ATR prism according to claim 1, wherein the recess includes a positioning portion for positioning a light source for irradiating the light on the incident portion.

8. The ATR prism according to claim 2, wherein the recess includes a positioning portion for positioning a light receiving portion for receiving the light emitted from the emitting portion.

9. The first recess includes a positioning portion for positioning a light source for irradiating the light on the incident portion, The ATR prism according to claim 3, wherein the second recess includes a positioning portion for positioning a light receiving portion for receiving the light emitted from the emitting portion.

10. The lens portion of the incident portion includes a plurality of lens portions, and the ATR prism according to claim 1 or 3.

11. The lens portion of the emitting portion includes a plurality of lens portions, and the ATR prism according to claim 2 or 3.

12. A method for manufacturing an ATR prism according to any one of claims 1 to 11, The method for manufacturing an ATR prism includes a forming step of forming the ATR prism by pressing with a mold while heating a base glass.

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