Biological component measurement device

Abstract

An optical medium (3) includes a first surface (31) and a second surface (32) on the opposite side from the first surface, and is transparent to excitation light (7). A bioprotective film (4) is provided on the first surface (31) of the optical medium (3) and is transparent to the excitation light (7). The bioprotective film (4) has a sample placement surface (41). An excitation light source (1) emits the excitation light (7). A probe light source (2) emits probe light (9) that progresses through the optical medium (3). The optical medium (3) is also transparent to the probe light (9). The excitation light (7) enters the optical medium (3) from the second surface (32) of the optical medium (3), and progresses through the optical medium (3) and the bioprotective film (4) toward a sample (8) placed on the sample placement surface (41). A light position detector (5) detects the positions of probe light beams (9a, 9b) emitted from the optical medium (3). A calculation device (6) measures the biological component of the sample (8) on the basis of the positions (10a, 10b) of the probe light beams detected by the light position detector (5).

Description

Biological component measuring device

[0001] The present disclosure relates to a biological component measuring device.

[0002] For example, Japanese Patent No. 6956930 (Patent Document 1) discloses a biological component measuring device that measures a biological component using heat generated by a sample that absorbs excitation light. In this biological component measuring device, a sample is placed on a sample-mounting surface of an optical medium. An excitation light source irradiates excitation light. The excitation light is irradiated onto the sample through the optical medium. The excitation light is absorbed by the sample, causing the sample to generate heat. The degree of heat absorption by the sample depends on the amount or concentration of the biological component in or on the surface of the sample.

[0003] The probe light source emits probe light toward the optical medium. The probe light is totally internally reflected at the interface between the optical medium and the biological sample and exits the optical medium. Heat absorbed by the sample is transferred to the optical medium, changing the refractive index of the optical medium. The change in the refractive index of the optical medium affects the total internal reflection of the probe light at the interface between the optical medium and the sample, changing the optical path of the probe light exiting the optical medium. The optical position detector detects the change in the direction of propagation of the probe light. The amount or concentration of the biological component is measured from the change in the direction of propagation of the probe light detected by the optical position detector.

[0004] Patent No. 6956930

[0005] In the biological component measuring device disclosed in Patent Document 1, the optical medium is formed of chalcogenide glass. Chalcogenide glass has a thermal conductivity of 0.36 W / (m·K), which is significantly lower than that of zinc selenide (ZnSe) and zinc sulfide (ZnS). This prevents the heat absorbed by the biological sample from rapidly spreading to areas of the optical medium other than the optical path of the probe light. This increases the temperature change in the portion of the optical medium located in the optical path of the probe light, resulting in a large change in the refractive index of the portion of the optical medium located in the optical path of the probe light. This allows for high-precision measurement of biological components.

[0006] As described above, chalcogenide glass is a suitable material for improving the measurement accuracy of biological component measuring devices. However, because chalcogenide glass contains antimony (Sb), which interferes with biological stability, when the sample is human skin, the optical medium must be replaced with an optical medium made of another material. The replaced optical medium has a higher thermal conductivity than chalcogenide glass, which may reduce the measurement accuracy of the biological component measuring device.

[0007] The irradiation positions of the excitation light and probe light relative to the optical medium are usually adjusted to maximize the change in the direction of travel of the probe light due to changes in the refractive index of the optical medium. Therefore, when the sample is both a biological component reagent and human skin, replacing the optical medium made of different materials requires readjustment of the irradiation positions of the excitation light and probe light. Since adjusting the irradiation positions of the excitation light and probe light requires accuracy of several micrometers, replacing the optical medium depending on the type of sample requires a significant amount of time and effort, which may reduce the efficiency of the measurement. Furthermore, replacing the optical medium may reduce the reliability of the comparison evaluation between the previous measurement results and the current measurement results for the same sample.

[0008] The present disclosure has been made in consideration of the above-mentioned problems, and its purpose is to provide a biological component measuring device that can measure biological components with improved accuracy regardless of the type of sample.

[0009] A biological component measuring device according to the present disclosure measures components using heat generated by a sample that has absorbed excitation light. The biological component measuring device includes an optical medium, a biological protective film, an excitation light source, a probe light source, a light position detector, and a computing device. The optical medium includes a first surface and a second surface opposite the first surface, and is transparent to the excitation light. The biological protective film is provided on the first surface of the optical medium and is transparent to the excitation light. The biological protective film has a sample placement surface. The excitation light source emits excitation light. The probe light source emits probe light that travels through the optical medium. The optical medium is also transparent to the probe light. The excitation light enters the optical medium from the second surface of the optical medium and travels through the optical medium and the biological protective film toward a sample placed on the sample placement surface. The light position detector detects the position of the probe light emitted from the optical medium. The computing device measures the biological component of the sample based on the position of the probe light detected by the light position detector.

[0010] The biological component measuring device according to the present disclosure allows for improved accuracy in measuring biological components, regardless of the type of sample. The biological component measuring device according to the present disclosure allows for improved accuracy in measuring biological components, regardless of the type of sample. ...

[0011] Furthermore, the biological component measuring device according to the present disclosure does not require replacement of the optical medium depending on the type of sample, nor does it require readjustment of the irradiation positions of the excitation light and probe light that accompanies such replacement, thereby improving the reliability of measurement results and making measurements more efficient.

[0012] FIG. 1 is a diagram showing the configuration of a biological component measuring device according to embodiment 1. FIG. 2 is a flowchart illustrating a biological component measuring method according to embodiment 1. FIG. 3 is a diagram showing the configuration of a biological component measuring device according to a modified example of embodiment 1. FIG. 4 is a diagram showing the configuration of a biological component measuring device according to embodiment 2. FIG. 5 is a diagram showing the configuration of a biological component measuring device according to embodiment 3. FIG. 6 is a schematic partial enlarged plan view of a biological component measuring device according to embodiment 3. FIG. 7 is a diagram showing the configuration of a biological component measuring device according to a modified example of embodiment 3. FIG. 8 is a diagram showing the configuration of a biological component measuring device according to embodiment 4. FIG. 9 is a schematic partial enlarged plan view of a biological component measuring device according to embodiment 5. FIG. 10 is a diagram showing the configuration of a biological component measuring device according to embodiment 6. FIG. 11 is a schematic partial enlarged plan view of a biological component measuring device according to embodiment 6.

[0013] Hereinafter, embodiments will be described, in which the same components are denoted by the same reference characters and the description thereof will not be repeated.

[0014] Embodiment 1. Figure 1 shows the configuration of a biological component measuring device 100 according to Embodiment 1. Biological component measuring device 100 according to Embodiment 1 is a device for non-invasively measuring a biological component in a sample 8. Sample 8 is, for example, human skin or a body fluid. When the substance to be measured is a liquid, sample 8 is the liquid contained in a transparent sample holder.

[0015] As shown in FIG. 1, the biological component measuring device 100 mainly includes an excitation light source 1 , a probe light source 2 , an optical medium 3 , a biological protective film 4 , a light position detector 5 , and a computing device 6 .

[0016] The optical medium 3 has a first surface 31, a second surface 32 opposite to the first surface 31, a third surface 33 connecting the first surface 31 and the second surface 32, and a fourth surface 34 connecting the first surface 31 and the second surface 32 and opposite to the third surface 33.

[0017] A biological protective film 4 is provided on a first surface 31 of the optical medium 3. A second surface 32 is an incident surface for excitation light 7 emitted from the excitation light source 1. A third surface 33 is an incident surface for probe light 9 emitted from the probe light source 2. The third surface 33 is inclined with respect to the incident direction of the probe light 9. A fourth surface 34 is an exit surface for the probe light 9. The fourth surface 34 is inclined with respect to the exit direction of the probe light 9. The optical medium 3 is, for example, a total internal reflection prism (TIR prism).

[0018] The optical medium 3 is transparent to the excitation light 7. In this specification, the optical medium 3 being transparent to the excitation light 7 means that the optical transmittance of the optical medium 3 to the excitation light 7 is 25% or more. The optical transmittance of the optical medium 3 to the excitation light 7 may be 50% or more, 75% or more, or 90% or more. The optical medium 3 is transparent to the probe light 9. In this specification, the optical medium 3 being transparent to the probe light 9 means that the optical transmittance of the optical medium 3 to the probe light 9 is 25% or more. The optical transmittance of the optical medium 3 to the probe light 9 may be 50% or more, 75% or more, or 90% or more.

[0019] The optical medium 3 is formed of a material having a thermal conductivity of 15.0 W / (m·K) or less. The thermal conductivity of the material forming the optical medium 3 may be 10.0 W / (m·K) or less, 5.0 W / (m·K) or less, 3.0 W / (m·K) or less, 2.0 W / (m·K) or less, or 1.0 W / (m·K) or less. The thermal conductivity of the material forming the optical medium 3 may be 0.75 times or more that of sample 8, may be greater than or equal to the thermal conductivity of sample 8, may be 1.5 times or more that of sample 8, or may be 2.0 times or more that of sample 8.

[0020] Preferably, the optical medium 3 is made of chalcogenite glass, which contains, for example, 2 mol % to 22 mol % germanium (Ge), 6 mol % to 34 mol % of at least one element selected from the group consisting of antimony (Sb) and bismuth (Bi), 1 mol % to 20 mol % of tin (Sn), and 58 mol % to 70 mol % of at least one element selected from the group consisting of sulfur (S), selenium (Se), and tellurium (Te).

[0021] The thermal conductivity of this chalcogenite glass is 0.36 W / (m·K). Chalcogenite glass has significantly lower thermal conductivity than zinc selenide (ZnSe, thermal conductivity 27 W / (m·K)) and zinc sulfide (ZnS, thermal conductivity 18 W / (m·K)), making it a suitable material for improving the measurement accuracy of the biological component measuring device 100. However, because chalcogenite glass contains antimony (Sb), which interferes with biological stability, if the sample 8 is human skin, the optical medium 3 must be replaced with an optical medium made of a different material, which may reduce the measurement accuracy of the biological component measuring device 100. Furthermore, replacing the optical medium 3 requires readjustment of the irradiation positions of the excitation light 7 and the probe light 9, which may adversely affect the reliability of the measurement results and the efficiency of the measurement.

[0022] To address these concerns, in this embodiment, a bioprotective film 4 is provided on the first surface 31 of the optical medium 3. The bioprotective film 4 makes it possible to prevent the sample 8 from being placed directly on the first surface 31 of the optical medium 3, i.e., to prevent the sample 8 from coming into contact with the first surface 31 of the optical medium 3. Therefore, when a biocomponent on human skin is measured using the biocomponent measuring device 100 that includes the optical medium 3 formed from chalcogenite glass, the human can be protected from the biological risks of the chalcogenite glass.

[0023] Preferably, the bioprotective film 4 is provided so as to cover the entire first surface 31 of the optical medium 3. This more reliably prevents the sample 8 from being placed directly on the first surface 31 of the optical medium 3. However, the bioprotective film 4 may also be provided so as to cover at least the portion of the first surface 31 of the optical medium 3 where the sample 8 is placed.

[0024] The bioprotective film 4 has a sample mounting surface 41. The sample 8 is mounted on the sample mounting surface 41 and is in contact with the sample mounting surface 41. The thickness of the bioprotective film 4 may be 0.5 μm or more, or may be 1.0 μm or more.

[0025] The bioprotective film 4 is transparent to the excitation light 7. In this specification, the bioprotective film 4 being transparent to the excitation light 7 means that the light transmittance of the bioprotective film 4 to the excitation light 7 is 25% or more. The light transmittance of the bioprotective film 4 to the excitation light 7 may be 50% or more, 75% or more, or 90% or more.

[0026] The biological protective film 4 may be transparent to the probe light 9. In this specification, the biological protective film 4 being transparent to the probe light 9 means that the light transmittance of the biological protective film 4 to the probe light 9 is 25% or more. The light transmittance of the biological protective film 4 to the probe light 9 may be 50% or more, 75% or more, or 90% or more.

[0027] However, the biological protective film 4 has a lower refractive index than the optical medium 3. This is because, as shown in Figure 1, the probe light 9 traveling through the optical medium 3 is totally internally reflected at the interface between the optical medium 3 and the biological protective film 4. The biological protective film 4 is made of, for example, zinc sulfide (ZnS, thermal conductivity 18 W / (m K)) or diamond-like carbon (DLC, thermal conductivity 1.4 to 2.1 W / (m K)).

[0028] The excitation light source 1 emits excitation light 7 toward a sample 8 placed on a sample placement surface 41. The excitation light 7 is emitted from the excitation light source 1 and enters the optical medium 3 from the second surface 32. The excitation light 7 travels through the optical medium 3 and the bioprotective film 4 and enters the sample 8 from the sample placement surface 41. The excitation light 7 is absorbed by biological components in the sample 8 or on the surface of the sample 8. For example, when measuring a patient's blood glucose level using the biological component measuring device 100, the biological component is sugar present in interstitial fluid in the epidermis. Absorption of the excitation light 7 by the biological component generates absorption heat in the sample 8. The absorption heat of the sample 8 is conducted to the optical medium 3 via the bioprotective film 4. This creates a temperature gradient region within the optical medium 3, resulting in a refractive index gradient region 12 within the optical medium 3.

[0029] Preferably, the bioprotective film 4 is made of a material having a low thermal conductivity and a refractive index lower than that of the optical medium 3. This is because if the bioprotective film 4 has a high thermal conductivity, the absorbed heat conducted from the sample 8 to the bioprotective film 4 will be diffused in the first direction (x direction) and / or the second direction (y direction) within the bioprotective film 4, reducing the amount of absorbed heat conducted to the optical medium 3.

[0030] The wavelength of the excitation light 7 is determined according to the absorption wavelength of the biological component in the sample 8 or on the surface of the sample 8. The wavelength of the excitation light 7 may be longer than the wavelength of the probe light 9. The wavelength of the excitation light 7 is, for example, infrared light having a wavelength of 3.0 μm or more and 20 μm or less. The excitation light 7 may be light having multiple wavelengths. For example, when measuring a patient's blood glucose level using the biological component measuring device 100, the wavelength range of the excitation light 7 is a wavelength range that includes the wavelengths of the sugar fingerprint spectrum (for example, a wavelength range of 8.5 μm or more and 10 μm or less). The excitation light source 1 is, for example, a quantum cascade laser that can emit broadband infrared light. Reference light that is not absorbed by the biological component in the sample 8 or on the surface of the sample 8 may be irradiated onto the sample 8 together with the excitation light 7.

[0031] The probe light source 2 emits probe light 9. The probe light 9 has, for example, a wavelength included in the visible to near-infrared wavelength range. The probe light source 2 is, for example, a semiconductor laser. The probe light 9 travels in a first direction (x direction) in a plan view of the sample placement surface 41.

[0032] Specifically, the probe light 9 enters the optical medium 3 from the third surface 33 of the optical medium 3. The probe light 9 is refracted at the third surface 33 and travels through the optical medium 3 toward the interface (first surface 31) between the optical medium 3 and the biological protective film 4. In a plan view of the sample mounting surface 41, the optical path of the probe light 9 in the optical medium 3 overlaps with the portion of the sample mounting surface 41 that is irradiated by the excitation light 7. The probe light 9 is totally internally reflected at the interface (first surface 31) between the optical medium 3 and the biological protective film 4.

[0033] While the probe light 9 travels through the optical medium 3, it travels through a refractive index gradient region 12 formed in the optical medium 3 by heat absorption by the sample 8. The probe light 9 is refracted in the refractive index gradient region 12, changing its traveling direction. The probe light 9 (first outgoing probe light 9a and second outgoing probe light 9b) is emitted from the fourth surface 34 of the optical medium 3.

[0034] The light position detector 5 detects the position of the probe light 9 (first emitted probe light 9a, second emitted probe light 9b) emitted from the optical medium 3. Specifically, the light position detector 5 detects a first position 10a of the probe light 9 (first emitted probe light 9a) when the excitation light 7 is not irradiated onto the sample 8. The light position detector 5 detects a second position 10b of the probe light 9 (second emitted probe light 9b) when the excitation light 7 is irradiated onto the sample 8.

[0035] The light position detector 5 outputs a first position 10a of the probe light 9 (first emitted probe light 9a) and a second position 10b of the probe light 9 (second emitted probe light 9b) to the calculation device 6. The light position detector 5 is, for example, a photodiode or a semiconductor position sensitive detector.

[0036] The calculation device 6 is connected to the light position detector 5. The calculation device 6 measures the biological component in the sample 8 or on the surface of the sample 8 from the displacement δ of the probe light 9 corresponding to the distance between the first position 10a and the second position 10b. The calculation device 6 is mainly composed of a computer, for example. In this case, the calculation device 6 includes a processor, a storage device, a communication interface, an input / output device, etc.

[0037] Next, a description will be given of a biological component measuring method using biological component measuring device 100. Fig. 2 is a flowchart illustrating the biological component measuring method according to the first embodiment.

[0038] The biological component measuring method according to this embodiment includes detecting (S1) a first position 10a of probe light 9 (first emitted probe light 9a) using a light position detector 5 without irradiating excitation light 7 onto sample 8. In a state where excitation light 7 is not irradiated onto sample 8 (hereinafter also referred to as the "reference state"), no heat is absorbed by sample 8, and therefore no temperature gradient region is generated within optical medium 3, and as a result, no refractive index gradient region 12 is generated within optical medium 3. Therefore, as shown by the solid line in FIG. 1 , probe light 9 (first emitted probe light 9a) within optical medium 3 is not refracted by refractive index gradient region 12 and is emitted from fourth surface 34 of optical medium 3. First position 10a is the position of probe light 9 in the reference state.

[0039] The biological component measurement method according to this embodiment includes detecting (S2) a second position 10b of the probe light 9 (second emitted probe light 9b) using the light position detector 5 while irradiating the sample 8 with the excitation light 7. When the excitation light 7 is irradiating the sample 8 (hereinafter also referred to as the "excited state"), the excitation light 7 is absorbed by a biological component in the sample 8 or on the surface of the sample 8, generating absorbed heat in the sample 8. The absorbed heat of the sample 8 is conducted to the optical medium 3 via the biological protective film 4. A temperature gradient region is generated within the optical medium 3, resulting in a refractive index gradient region 12 within the optical medium 3. Therefore, as shown by the dashed line in FIG. 1 , the probe light 9 (second emitted probe light 9b) in the optical medium 3 is refracted by the refractive index gradient region 12 and emitted from the fourth surface 34 of the optical medium 3. The second position 10b is the position of the probe light 9 in the excited state. By irradiating the sample 8 with the excitation light 7, the position of the probe light 9 detected by the light position detector 5 is displaced from a first position 10a to a second position 10b.

[0040] The biological component measuring method according to this embodiment includes calculating (S3) the displacement amount δ of the probe light 9. Specifically, the calculation device 6 calculates the displacement amount δ of the probe light 9 corresponding to the distance between the first position 10a and the second position 10b.

[0041] The biological component measurement method according to this embodiment includes measuring (S4) a biological component in sample 8 or on the surface of sample 8 from the displacement δ of probe light 9. For example, calculation device 6 stores in a storage device a data table in which the type of biological component, the displacement δ of probe light 9, and the amount or concentration of the biological component are associated. Calculation device 6 references this data table to obtain the amount or concentration of the biological component in sample 8 or on the surface of sample 8 from the type of biological component and the displacement δ of probe light 9.

[0042] <Modification> Fig. 3 is a diagram showing the configuration of a biological component measuring device 100a according to a modification of Embodiment 1. As shown in Fig. 3, the biological component measuring device 100a according to this modification differs from the biological component measuring device 100 shown in Fig. 1 in that it includes an optical chopper 13 and a lock-in amplifier 14.

[0043] The optical chopper 13 is disposed in the optical path of the excitation light 7. The optical chopper 13 chops the excitation light 7 (continuous light) emitted from the excitation light source 1 at an arbitrary frequency. The excitation light 7 becomes intermittent light (pulsed light) that is turned on and off at a period corresponding to the chopping frequency (frequency at which light is turned on and off) of the optical chopper 13, and is incident on the optical medium 3. The optical chopper 13 corresponds to one example of a "modulator" for intensity modulating the excitation light 7. The chopping frequency of the optical chopper 13 corresponds to a "modulation frequency" for modulating the excitation light 7. A well-known configuration can be applied to the optical chopper 13.

[0044] The lock-in amplifier 14 is connected to the optical position detector 5 and the optical chopper 13. Based on the chopping frequency (modulation frequency) of the optical chopper 13, the lock-in amplifier 14 selectively amplifies a signal synchronized with the chopping frequency (modulation frequency) among signals related to the position of the probe light 9 output from the optical position detector 5.

[0045] Specifically, the lock-in amplifier 14 outputs to the calculation device 6 a signal obtained by amplifying the difference between a first position 10a of the probe light 9 (first emitted probe light 9a) during an on-period of the chopping frequency of the optical chopper 13 (corresponding to a period during which the excitation light 7 is irradiated onto the sample 8) and a second position 10b of the probe light 9 (second emitted probe light 9b) during an off-period of the chopping frequency (corresponding to a period during which the excitation light 7 is not irradiated onto the sample 8).

[0046] The output signal of the lock-in amplifier 14 is a signal from which noise contained in the signal relating to the position of the probe light 9 output from the light position detector 5 has been removed, thereby enabling the biological component measuring device 100a to measure biological components with improved accuracy.

[0047] <Effects> The effects of biological component measuring devices 100 and 100a according to the first embodiment will be described.

[0048] The biological component measuring device 100, 100a according to the first embodiment includes a biological protective film 4 having a sample mounting surface 41. The biological protective film 4 is provided on the first surface 31 of the optical medium 3 and is transparent to the excitation light 7. Therefore, the excitation light 7 emitted from the excitation light source 1 enters the optical medium 3 from the second surface 32 of the optical medium 3, travels through the optical medium 3 and the biological protective film 4 toward the sample 8 mounted on the sample mounting surface 41, and enters the sample 8 from the sample mounting surface 41.

[0049] In this way, the bioprotective film 4 allows the excitation light 7 traveling through the optical medium 3 to be incident on the sample 8, while preventing the sample 8 from coming into contact with the first surface 31 of the optical medium 3. This allows the optical medium 3 to be formed of chalcogenide glass, which has a lower thermal conductivity than zinc selenide (ZnSe) and zinc sulfide (ZnS), even when the sample 8 is human skin.

[0050] As a result, the biological component measuring devices 100 and 100a enable measurement of biological components with improved accuracy regardless of the type of sample 8. Furthermore, the biological component measuring devices 100 and 100a eliminate the need to replace the optical medium 3 depending on the type of sample 8, and also eliminate the need to readjust the irradiation positions of the excitation light 7 and probe light 9 that accompany such replacement. Therefore, the biological component measuring devices 100 and 100a enable improved reliability of measurement results and more efficient measurement.

[0051] In the biological component measuring devices 100 and 100a, the biological protective film 4 has low thermal conductivity, which prevents the heat generated from the sample 8 irradiated with the excitation light 7 from diffusing within the biological protective film 4 and efficiently conducts the heat to the optical medium 3. This increases the temperature change in the temperature gradient region in the optical medium 3, resulting in a large change in the refractive index of the refractive index gradient region 12 in the optical medium 3. The biological component measuring devices 100 and 100a enable measurement of biological components with improved accuracy.

[0052] In the biological component measuring devices 100 and 100a, the biological protective film 4 has a refractive index smaller than that of the optical medium 3. The probe light 9 traveling through the optical medium 3 is totally internally reflected at the interface (first surface 31) between the optical medium 3 and the biological protective film 4 and is emitted from the optical medium 3. Therefore, the provision of the biological protective film 4 can prevent a decrease in the amount of the probe light 9 emitted from the optical medium 3. The biological component measuring devices 100 and 100a enable measurement of biological components with improved accuracy.

[0053] 4 is a diagram showing the configuration of a biological component measuring device 100b according to embodiment 2. Biological component measuring device 100b according to embodiment 2 has the same configuration and produces the same effects as biological component measuring device 100 according to embodiment 1, but differs mainly in the following respects.

[0054] 4, in the biological component measuring device 100b, the third surface 33 of the optical medium 3 is perpendicular to the incident direction of the probe light 9. The fourth surface 34 of the optical medium 3 is perpendicular to the exit direction of the probe light 9.

[0055] The probe light 9 enters the optical medium 3 from the third surface 33 of the optical medium 3. The probe light 9 travels through the optical medium 3 along the first surface 31 of the optical medium 3. While the probe light 9 travels through the optical medium 3, the probe light 9 travels through a refractive index gradient region 12 that is generated in the optical medium 3 by heat absorbed by the sample 8. The probe light 9 is refracted in the refractive index gradient region 12, changing its traveling direction. The probe light (first outgoing probe light 9a, second outgoing probe light 9b) is emitted from the fourth surface 34 of the optical medium 3. In a plan view of the sample setting surface 41, the optical path of the probe light 9 in the optical medium 3 overlaps with the portion of the sample setting surface 41 that is irradiated with the excitation light 7.

[0056] In the biological component measuring device 100 according to the first embodiment, the probe light 9 is refracted at the third surface 33 and travels through the optical medium 3 toward the interface between the optical medium 3 (first surface 31) and the biological protective film 4. In order to cause total internal reflection of the probe light at the interface between the optical medium 3 and the biological protective film 4, the biological protective film 4 is made of a material having a refractive index smaller than that of the optical medium 3.

[0057] In contrast, in the biological component measuring device 100b according to the second embodiment, the probe light 9 travels through the optical medium 3 along the first surface 31 of the optical medium 3 without being refracted at the third surface 33. This eliminates the need for total internal reflection at the interface (first surface 31) between the optical medium 3 and the biological protective film 4. Therefore, there are no restrictions on the refractive index of the material forming the biological protective film 4. This broadens the range of materials available for the biological protective film 4. The biological protective film 4 may be made of any material that is transparent to mid-infrared light and has a low thermal conductivity. This is because, as the thermal conductivity of the biological protective film 4 increases, the heat absorbed by the sample 8 is more likely to diffuse within the biological protective film 4, resulting in a decrease in the amount of absorbed heat conducted to the optical medium 3. The decrease in absorbed heat conducted to the optical medium 3 reduces the displacement δ of the probe light 9 corresponding to the distance between the first position 10a and the second position 10b, potentially reducing the accuracy of biological component measurement.

[0058] 5 is a diagram showing the configuration of a biological component measuring device 100c according to embodiment 3. Biological component measuring device 100c according to embodiment 3 has the same configuration and effects as biological component measuring device 100 according to embodiment 1, but differs mainly in the following respects.

[0059] 5 , the biological component measuring device 100c includes a high thermal conductor 15. The high thermal conductor 15 is provided between the first surface 31 of the optical medium 3 and the biological protective film 4. The high thermal conductor 15 has a higher thermal conductivity than the biological protective film 4. The thermal conductivity of the high thermal conductor 15 may be, for example, 1.5 times or more the thermal conductivity of the biological protective film 4. The thermal conductivity of the high thermal conductor 15 may be, for example, 2.0 times or more the thermal conductivity of the biological protective film 4.

[0060] 6 is a schematic partial enlarged plan view of a biological component measuring device 100c according to a third embodiment. As shown in FIG. 6 , in a plan view of the sample mounting surface 41, the high thermal conductor 15 overlaps a portion 7r of the sample mounting surface 41 that is irradiated by the excitation light 7. The high thermal conductor 15 is transparent to the excitation light 7. In this specification, the transparency of the high thermal conductor 15 to the excitation light 7 means that the light transmittance of the high thermal conductor 15 to the excitation light 7 is 25% or more. The light transmittance of the high thermal conductor 15 to the excitation light 7 may be 50% or more, 75% or more, or 90% or more.

[0061] The high thermal conductor 15 may be transparent to the probe light 9. In this specification, the high thermal conductor 15 being transparent to the probe light 9 means that the light transmittance of the high thermal conductor 15 to the probe light 9 is 25% or more. The light transmittance of the high thermal conductor 15 to the probe light 9 may be 50% or more, 75% or more, or 90% or more.

[0062] However, the high thermal conductor 15 has a refractive index lower than that of the optical medium 3. This is because, as shown in Fig. 5, the probe light 9 traveling through the optical medium 3 is totally internally reflected at the interface between the optical medium 3 and the high thermal conductor 15. The high thermal conductor 15 is made of, for example, zinc sulfide (ZnS, thermal conductivity 27.2 W / (m K)) or zinc selenide (ZnSe, thermal conductivity 18.0 W / (m K)).

[0063] In the biological component measuring device 100c, heat generated from the sample 8 irradiated with the excitation light 7 is conducted isotropically within the biological protective film 4. However, because the high thermal conductor 15 has a higher thermal conductivity than the biological protective film 4, most of the heat conducted within the biological protective film 4 is conducted to the optical medium 3 via the high thermal conductor 15. In other words, the high thermal conductor 15 has the function of quickly conducting the heat generated from the sample 8 to the optical medium 3.

[0064] The high thermal conductor 15 spreads the heat generated from the sample 8 irradiated with the excitation light 7 more in the first direction (x direction) than in the second direction (y direction). The first direction (x direction) is the traveling direction of the probe light 9 in a plan view of the sample mounting surface 41. The second direction (y direction) is a direction perpendicular to the first direction (x direction) in a plan view of the sample mounting surface 41. In a plan view of the sample mounting surface 41, the high thermal conductor 15 overlaps the probe light 9 in the first direction (x direction).

[0065] In a plan view of the sample mounting surface 41, the high thermal conductor 15 has a rectangular shape with its longitudinal direction in the first direction (x direction) and its lateral direction in the second direction (y direction). The thickness of the high thermal conductor 15 may be less than the thickness of the bioprotective film 4.

[0066] In a plan view of the sample mounting surface 41, the high thermal conductor 15 crosses the irradiated portion 7r in the first direction (x direction). The length of the high thermal conductor 15 in the first direction (x direction) is greater than the diameter D of the irradiated portion 7r. The length of the high thermal conductor 15 in the second direction (y direction) may be smaller than the diameter D of the irradiated portion 7r.

[0067] The length of the high thermal conductor 15 in the second direction (y direction) may be greater than the length (width) of the probe light 9 in the second direction (y direction). In a plan view of the sample mounting surface 41, the high thermal conductor 15 may be formed symmetrically with respect to the optical axis of the irradiation portion 7r or the excitation light 7 in the first direction (x direction) and the second direction (y direction).

[0068] <Modification> Fig. 7 is a diagram showing the configuration of a biological component measuring device 100d according to a modification of embodiment 3. As shown in Fig. 7, biological component measuring device 100d according to this modification is obtained by providing high thermal conductor 15 to biological component measuring device 100b according to embodiment 2 shown in Fig. 4.

[0069] As shown in FIG. 7 , in the biological component measuring device 100d, the probe light 9 travels through the optical medium 3 along the first surface 31 of the optical medium 3 without being refracted at the third surface 33, so there are no restrictions on the refractive index of the material forming the high thermal conductor 15. This broadens the range of materials available for the high thermal conductor 15. For example, it is possible to select a material with a higher thermal conductivity than the biological protective film 4 that can more efficiently conduct the heat absorbed by the sample 8, generated by absorbing the excitation light, to the optical medium 3. In the biological component measuring device 100d, the high thermal conductor 15 is formed, for example, from silicon (Si: thermal conductivity 160 W / (m·K)) or germanium (Ge: thermal conductivity 59 W / (m·K)).

[0070] <Effects> Biological component measuring devices 100c and 100d according to the third embodiment have the following effects in addition to the effects of biological component measuring device 100 according to the first embodiment.

[0071] In the biological component measuring devices 100c and 100d according to the third embodiment, the high thermal conductor 15 has a higher thermal conductivity than the biological protective film 4 and is provided between the biological protective film 4 and the first surface 31 of the optical medium 3. The high thermal conductor 15 enables the heat generated from the sample 8 irradiated with the excitation light 7 to be conducted to the optical medium 3 faster than the heat can be diffused within the biological protective film 4.

[0072] The high thermal conductor 15 spreads the heat generated from the sample 8 irradiated with the excitation light 7 in the first direction (x direction) more than in the second direction (y direction). The first direction (x direction) is the traveling direction of the probe light 9 in a plan view of the sample mounting surface 41. The second direction (y direction) is a direction perpendicular to the first direction (x direction) in a plan view of the sample mounting surface 41.

[0073] High thermal conductor 15 concentrates the temperature gradient region of optical medium 3, which is caused by heat generated from sample 8 irradiated with excitation light 7, to the portion of optical medium 3 in the optical path of probe light 9. This increases the temperature change in the portion of optical medium 3 in the optical path of probe light 9 (temperature gradient region), and increases the length of the temperature gradient region through which probe light 9 propagates. That is, increases the change in refractive index in the portion of optical medium 3 in the optical path of probe light 9 (refractive index gradient region 12), and increases the length of refractive index gradient region 12 through which probe light 9 propagates. Because the displacement δ of probe light 9 detected by light position detector 5 increases, biological component measuring devices 100c and 100d enable measurement of biological components with improved accuracy.

[0074] In the biological component measuring devices 100c and 100d, the high thermal conductor 15 is transparent to the excitation light 7. Therefore, the excitation light 7 emitted from the excitation light source 1 enters the optical medium 3 from the second surface 32 of the optical medium 3, travels through the optical medium 3, the high thermal conductor 15, and the biological protective film 4 toward the sample 8 placed on the sample mounting surface 41, and is incident on the sample 8 from the sample mounting surface 41. In this way, the high thermal conductor 15 allows the excitation light 7 traveling through the optical medium 3 to enter the sample 8, while efficiently conducting heat generated from the sample 8 irradiated with the excitation light 7 to the optical medium 3. Therefore, a material having a higher thermal conductivity than the biological protective film 4 of the first embodiment can be used as the material for the biological protective film 4 of the third embodiment.

[0075] Embodiment 4 Fig. 8 is a diagram showing the configuration of biological component measuring device 100e according to embodiment 4. Fig. 9 is a schematic partial enlarged plan view of biological component measuring device 100e according to embodiment 4. Biological component measuring device 100e according to embodiment 4 has the same configuration and produces the same effects as biological component measuring device 100c according to embodiment 3, but differs mainly in the following respects.

[0076] 8 , in the biological component measuring device 100e, the high thermal conductor 15 has a first contact surface 151 that contacts the first surface 31 of the optical medium 3, and a second contact surface 152 on the opposite side of the first contact surface 151. The second contact surface 152 contacts the biological protective film 4. As shown in FIG. 9 , in a plan view of the sample placement surface 41, the area of ​​the first contact surface 151 is smaller than the area of ​​the second contact surface 152.

[0077] <Effects> Biological component measuring device 100e according to the fourth embodiment has the following effects in addition to the effects of biological component measuring device 100c according to the third embodiment.

[0078] In the biological component measuring device 100e, heat generated from the sample 8 irradiated with the excitation light 7 is conducted through the bioprotective film 4 and the high thermal conductor 15 and then conducted from the first contact surface 151 to the optical medium 3. The high thermal conductor 15 concentrates the temperature gradient region of the optical medium 3, caused by the heat generated from the sample 8 irradiated with the excitation light 7, in the peripheral portion of the first contact surface 151. This increases the temperature change in the temperature gradient region of the optical medium 3 formed in the peripheral portion of the first contact surface 151. That is, the refractive index change in the refractive index gradient region 12 of the optical medium 3 formed in the peripheral portion of the first contact surface 151 increases. This increases the displacement δ of the probe light 9 detected by the light position detector 5, enabling the biological component measuring device 100e to measure biological components with improved accuracy.

[0079] In the biological component measuring device 100e, by increasing the ratio of the area of ​​the second contact surface 152 to the area of ​​the first contact surface 151, it is possible to increase the contact area between the biological protective film 4 and the high thermal conductor 15 while maintaining the area of ​​the first contact surface 151. This allows the high thermal conductor 15 to collect a large amount of heat from the biological protective film 4 and conduct it to the optical medium 3. This increases the temperature change in the temperature gradient region of the optical medium 3 formed around the first contact surface 151, resulting in a large change in the refractive index of the refractive index gradient region 12 of the optical medium 3. Because the displacement δ of the probe light 9 detected by the optical position detector 5 increases, the biological component measuring device 100d enables measurement of biological components with improved accuracy.

[0080] 10 is a schematic partial enlarged plan view of a biological component measuring device 100f according to embodiment 5. Biological component measuring device 100f according to embodiment 5 has the same configuration and effects as biological component measuring device 100c according to embodiment 3, but differs mainly in the following respects.

[0081] 10 , in the biological component measuring device 100f, at least one opening 16 is provided in a portion of the high thermal conductor 15 that overlaps the irradiation portion 7r. Multiple openings 16 may be provided in the portion of the high thermal conductor 15 that overlaps the irradiation portion 7r. The diameter of the openings 16 is smaller than the diameter of the irradiation portion 7r. In a plan view of the sample placement surface 41, the total area of ​​the openings 16 may be 50% or more of the area of ​​the portion of the high thermal conductor 15 that overlaps the irradiation portion 7r, or may be 80% or more of the area of ​​the portion of the high thermal conductor 15 that overlaps the irradiation portion 7r.

[0082] Since the high thermal conductor 15 is not present in a part of the irradiation portion 7r, a larger amount of excitation light 7 can be irradiated onto the sample 8. Therefore, as the material of the high thermal conductor 15 of the fifth embodiment, a material having a lower transmittance to the excitation light 7 but a higher thermal conductivity than the material of the high thermal conductor 15 of the first embodiment can be used.

[0083] <Effects> Biological component measuring device 100f according to the fifth embodiment has the following effects in addition to the effects of biological component measuring device 100c according to the third embodiment.

[0084] In the biological component measuring device 100f, at least one opening 16 is provided in the high thermal conductor 15 at a portion overlapping the irradiation portion 7r. This allows more excitation light 7 to be irradiated onto the sample 8, increasing the heat absorbed by the sample 8. Furthermore, a material with lower transmittance to the excitation light 7 but higher thermal conductivity can be used for the high thermal conductor 15. This further increases the temperature change in the portion of the optical medium 3 in the optical path of the probe light 9 (temperature gradient region). This further increases the refractive index change in the portion of the optical medium 3 in the optical path of the probe light 9 (refractive index gradient region 12). Because the displacement δ of the probe light 9 detected by the optical position detector 5 is increased, the biological component measuring device 100f enables measurement of biological components with improved accuracy.

[0085] Sixth Embodiment Fig. 11 is a diagram showing the configuration of a biological component measuring device 100g according to a sixth embodiment. Fig. 12 is a schematic partial enlarged plan view of the biological component measuring device 100g according to the sixth embodiment. The biological component measuring device 100g according to the sixth embodiment has the same configuration and effects as the biological component measuring device 100c according to the third embodiment, but differs mainly in the following respects.

[0086] In the biological component measuring device 100g, in a plan view of the sample mounting surface 41, the high thermal conductor 15 is spaced apart from the entire irradiation portion 7r in a first direction (x direction). Specifically, the high thermal conductor 15 includes a plurality of high thermal conductor portions 17. The plurality of high thermal conductor portions 17 are arranged in the first direction (x direction) with a gap G between them. In a plan view of the sample mounting surface 41, the irradiation portion 7r is located between a pair of adjacent high thermal conductor portions 17. The gap G between a pair of adjacent high thermal conductor portions 17 is equal to or greater than the diameter D of the irradiation portion 7r.

[0087] Each of the plurality of high thermal conductor portions 17 spreads the heat generated by the sample 8 irradiated with the excitation light 7 in the first direction (x direction) more than in the second direction (y direction). In a plan view of the sample mounting surface 41, the entire irradiated portion 7r is separated from the high thermal conductor 15. Therefore, the high thermal conductor 15 of the sixth embodiment can be formed of a material that has a higher thermal conductivity than the material forming the high thermal conductor 15 of the first embodiment, but has a lower transmittance to the excitation light 7.

[0088] <Effects> Biological component measuring device 100g according to the sixth embodiment has the following effects in addition to the effects of biological component measuring device 100c according to the third embodiment.

[0089] In the biological component measuring device 100g, in a plan view of the sample placement surface 41, the high thermal conductor 15 is spaced apart from the entire irradiated portion 7r in the first direction (x direction).

[0090] Therefore, all of the excitation light 7 incident on the irradiation portion 7r is irradiated onto the sample 8, increasing the heat absorbed by the sample 8. Furthermore, a material with higher thermal conductivity but lower transmittance to the excitation light 7 can be used as the material for the high thermal conductor 15. This further increases the temperature change in the portion of the optical medium 3 in the optical path of the probe light 9 (the temperature gradient region), and further increases the refractive index change in the portion of the optical medium 3 in the optical path of the probe light 9 (the refractive index gradient region 12). This increases the displacement δ of the probe light 9 detected by the light position detector 5, enabling the biological component measuring device 100g to measure biological components with improved accuracy.

[0091] The first to sixth embodiments and their modifications disclosed herein should be considered to be illustrative in all respects and not restrictive. Unless there is a contradiction, at least two of the first to sixth embodiments and their modifications disclosed herein may be combined. The scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0092] REFERENCE SIGNS LIST 1 Excitation light source, 2 Probe light source, 3 Optical medium, 4 Biological protection film, 5 Light position detector, 6 Arithmetic unit, 7 Excitation light, 7r Irradiated portion, 8 Sample, 9 Probe light, 9a First emitted probe light, 9b Second emitted probe light, 10a First position, 10b Second position, 12 Refractive index gradient region, 13 Optical chopper, 14 Lock-in amplifier, 15 High thermal conductor, 16 Opening, 17 High thermal conductor portion, 31 First surface, 32 Second surface, 33 Third surface, 34 Fourth surface, 41 Sample placement surface, 100, 100a to 100g Biological component measuring device, 151 First contact surface, 152 Second contact surface.

Claims

1. A biological component measuring device that measures components using heat generated by a sample that has absorbed excitation light, comprising: an optical medium that includes a first surface and a second surface opposite to the first surface and is transparent to the excitation light; a biological protective film that is provided on the first surface of the optical medium and is transparent to the excitation light and has a sample placement surface; an excitation light source that emits the excitation light; and a probe light source that emits probe light that travels through the optical medium, wherein the optical medium is also transparent to the probe light, and the excitation light enters the optical medium from the second surface of the optical medium and travels through the optical medium and the biological protective film toward the sample placed on the sample placement surface; an optical position detector that detects the position of the probe light emitted from the optical medium; and a computing device that measures the biological component of the sample based on the position of the probe light detected by the optical position detector.

2. The biological component measuring device of claim 1, wherein, in a planar view of the sample placement surface, the optical path of the probe light in the optical medium overlaps with the portion of the sample placement surface that is irradiated by the excitation light, the biological protective film has a refractive index smaller than that of the optical medium, and the probe light that enters the optical medium is totally internally reflected at the interface between the optical medium and the biological protective film at the first surface of the optical medium, and is then emitted from the optical medium.

3. The biological component measuring device of claim 1, wherein, in a planar view of the sample placement surface, the optical path of the probe light in the optical medium overlaps with the portion of the sample placement surface that is irradiated by the excitation light, and the probe light that enters the optical medium travels through the optical medium along the first surface of the optical medium and is emitted from the optical medium.

4. The biological component measuring device according to any one of claims 1 to 3, wherein the optical medium is formed of chalcogenide glass.

5. The biological component measuring device according to claim 4, wherein the biological protection film is provided so as to cover the entire first surface of the optical medium.

6. The biological component measuring device of claim 2, further comprising a high thermal conductor having a thermal conductivity higher than that of the biological protective film, wherein the high thermal conductor is disposed between the first surface of the optical medium and the biological protective film and has a refractive index lower than that of the optical medium, wherein the high thermal conductor spreads the heat generated from the sample irradiated with the excitation light in a first direction more than in a second direction, wherein the first direction is the direction of travel of the probe light in a planar view of the sample mounting surface, and wherein the second direction is a direction perpendicular to the first direction in a planar view of the sample mounting surface.

7. The biological component measuring device of claim 3, further comprising a high thermal conductor having a thermal conductivity higher than that of the biological protective film, the high thermal conductor being disposed between the first surface of the optical medium and the biological protective film, the high thermal conductor spreading the heat generated from the sample irradiated with the excitation light in a first direction more than in a second direction, the first direction being the direction of travel of the probe light in a planar view of the sample mounting surface, and the second direction being a direction perpendicular to the first direction in a planar view of the sample mounting surface.

8. The biological component measuring device according to claim 6 or 7, wherein, in the plan view of the sample placement surface, the high thermal conductor overlaps the probe light in the first direction.

9. The biological component measuring device described in claim 8, wherein the high thermal conductor has a first contact surface that contacts the first surface of the optical medium and a second contact surface opposite the first contact surface that contacts the biological protective film, and in the planar view of the sample placement surface, the area of ​​the first contact surface is smaller than the area of ​​the second contact surface.

10. The biological component measuring device according to claim 8, wherein at least one opening is provided in the portion of said highly thermally conductive body that overlaps with said irradiated portion.

11. The biological component measuring device according to claim 8, wherein the high thermal conductor includes a plurality of high thermal conductor portions, and the plurality of high thermal conductor portions are spaced apart from the irradiated portion in the first direction.

12. A biological component measuring device as described in any one of claims 1 to 11, wherein the calculation device measures the components of the sample based on a first position of the probe light detected by the light position detector when the excitation light source is not emitting the excitation light, and a second position of the probe light detected by the light position detector when the excitation light source is emitting the excitation light.

Images