JP2009153664A - Biological component concentration measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biological component concentration measuring apparatus capable of reducing influence of radiation light from an ear canal and highly accurately measuring a biological component concentration. <P>SOLUTION: The measuring apparatus of the biological component concentration includes: an insertion part provided with a light guide to be inserted to an earhole, where the light guide propagates infrared light made incident on a first opening opened inside the earhole and outputs it from a second opening when inserted to the earhole; a detector disposed with a gap from the second opening of the light guide, for detecting a part of the infrared light outputted from the second opening; an operation part for calculating the concentration of the biological components on the basis of the infrared light detected by a detector; an optical path cover provided so as to cover the gap from the second opening of the light guide to the detector and having an inner diameter larger than the outer diameter of the detector; and a light scattering part for scattering and attenuating the infrared light not made incident on the detector. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a biological component concentration measuring apparatus that non-invasively measures biological information using infrared radiation from a living body.

  As a device for measuring the concentration of a biological component, a device that noninvasively measures a blood glucose level using infrared radiation from a living body, particularly the eardrum has been proposed. For example, Patent Document 1 discloses an apparatus for determining a blood glucose level by non-invasively measuring radiation spectrum lines characteristic of human tissue in infrared rays that are naturally emitted from the eardrum as heat.

  However, according to Planck's law, infrared radiation due to heat always exists from an object having temperature. Therefore, not only the eardrum but also the ear canal becomes a radiation source of infrared light. In the conventional measuring apparatus, infrared light emitted from the eardrum and infrared light emitted from the ear canal enter the infrared detector and detect them together.

  However, infrared light emitted from the ear canal is a factor that degrades the measurement accuracy. The reason is that the amount of blood information contained in the infrared light emitted from the ear canal is small compared to the infrared light emitted from the eardrum, and other unnecessary information, that is, a relatively large amount of noise is contained. This is because. This is because the skin of the ear canal is thicker than the eardrum, and blood supply is performed at a relatively deep position.

  There are other examples in which infrared light emitted from the ear canal acts as noise. As an example of an ear thermometer that measures the body temperature of a living body using infrared light emitted from the eardrum, the temperature of the ear canal is lower than the temperature of the eardrum, so the influence of infrared light emitted from the ear canal Ear thermometers sometimes measured body temperature lower than the actual temperature.

  Therefore, techniques for reducing the influence of infrared light emitted from the ear canal have been proposed. For example, an ear canal thermometer disclosed in Patent Document 2 is configured to dispose infrared light emitted from the external auditory canal by disposing a waveguide that propagates infrared light and a non-contact temperature sensor at an interval Lb. The amount incident on the contact-type temperature sensor is reduced.

  On the other hand, there are other examples in which infrared light becomes noise. For example, in a radiation thermometer that calculates the body temperature by detecting infrared light emitted from a living body (object to be measured), since the infrared detector has a large field of view, a relatively wide range of infrared rays is transmitted to the infrared detector. Incident. Therefore, since an average value of temperatures in a wide range of the object to be measured is handled as a measured value, an accurate body temperature cannot be calculated.

Therefore, in order to narrow the field of view of the infrared detector, for example, in Patent Document 3, an infrared transmission hole is provided, and a secondary curved surface body in which infrared reflection is enhanced by making the inner surface a mirror surface, and infrared light incident from the infrared transmission hole An apparatus having an infrared sensor unit for detection is disclosed. In this apparatus, the infrared sensor unit is installed at the focal position of the quadric surface body.
JP-T-2001-503999 Japanese Patent Laid-Open No. 11-281484 JP-A-11-160156

  The apparatus described in Patent Document 1 has a problem in that the measurement accuracy is not high because no consideration is given to the influence of infrared light from the ear canal.

  In the apparatus described in Patent Document 2, the sensor frame that fixes the non-contact type temperature sensor and the non-contact type temperature sensor are in contact with each other without a gap. As a result, the sensor frame functions as a light guide tube, and the infrared light radiated from the ear canal is repeatedly reflected by the sensor frame to enter the non-contact temperature sensor. Such infrared light also causes measurement accuracy to deteriorate. According to Kirchhoff's law, if the sensor frame is composed of an infrared absorber, the absorptivity of the sensor frame is high and the emissivity increases, and the infrared light of the sensor frame itself is incident on the non-contact temperature sensor. End up. Therefore, it causes the measurement accuracy to deteriorate similarly.

  Moreover, in the apparatus described in Patent Document 3, since the infrared sensor is installed at the focal position, the infrared light emitted from the infrared sensor deteriorates the measurement accuracy. This is because the infrared sensor itself emits infrared because it has temperature, and the self-radiated light is reflected by the secondary curved surface and the plane on which the infrared sensor is provided, and is incident on the infrared sensor again. Is the cause.

  The present invention has been made in view of the above-described conventional problems, and provides a biological component concentration measuring apparatus capable of reducing the influence of radiated light from the ear canal and measuring the biological component concentration with high accuracy. The purpose is to do.

  The biological component concentration measuring apparatus of the present invention is an insertion portion provided with a light guide tube that is inserted into an ear canal, and the light guide tube opens into the ear canal when inserted into the ear hole. An infrared ray that propagates infrared light incident on the first opening and outputs it from the second opening, and the infrared light that is disposed apart from the second opening and is output from the second opening. A detector that detects a part of the light; an arithmetic unit that calculates a concentration of a biological component based on infrared light detected by the detector; and at least one of a space from the second opening to the detector And an optical path cover having an inner diameter larger than the outer diameter of the detector, and a light scattering section that scatters and attenuates infrared light that is not incident on the detector.

  In a preferred embodiment, the light scattering unit scatters infrared light that has passed through a space between the outer diameter of the detector and the inner diameter of the optical path cover.

  In a preferred embodiment, the light guide tube has a linear shape, and the detector is disposed on an extension line of the light guide tube.

  In a preferred embodiment, the inner surface of the optical path cover is formed of a material having a reflectance equal to or higher than a predetermined reflectance with respect to the infrared light.

  In a preferred embodiment, the light guide tube has a linear shape, and the inner surface of the optical path cover has an aspherical shape.

  In a preferred embodiment, the aspherical shape is a parabolic shape.

  In a preferred embodiment, the focal point of the paraboloid is adjusted so as to be located at the center of the second opening.

  In a preferred embodiment, the calculation unit holds data defining a correspondence between a detection value of infrared light and a concentration value of a biological component, and the data is based on the detection value of infrared light by the detector. The density value is specified with reference to FIG.

  The biological component concentration measuring apparatus of the present invention is an insertion portion provided with a first light guide tube that is inserted into an ear canal, and the first light guide tube is inserted into the ear hole when the first light guide tube is inserted into the ear hole. Infrared light incident on the first opening that opens inside is transmitted and output from the second opening. The insertion portion is spaced from the second opening and is output from the second opening. Based on the detector that detects a part of the infrared light, the second light guide tube provided between the second opening and the detector, and the infrared light detected by the detector A calculation unit for calculating a concentration of a biological component; and an inner diameter that is provided so as to cover at least a part of a space from the second opening to the detector and that is larger than an outer diameter of the second light guide tube An optical path cover; and a light scattering portion that scatters and attenuates infrared light not incident on the second light guide tube There.

  According to the biological information measuring apparatus of the present invention, the inner diameter of the optical path cover is configured to be larger than the outer diameter of the detector, and infrared light is released from the gap between the optical path cover and the detector. Further, the escaped infrared light is scattered by the light scattering portion. The amount of infrared light from the ear canal entering the detector can be reduced, and noise in the measurement can be reduced, so that the measurement accuracy can be improved.

  By measuring infrared light radiated from a living body, it is possible to obtain biological component concentration information such as blood glucose level. In the following, the principle will be described first, and the functional configuration of the biological component concentration measuring apparatus according to the present invention operating based on the principle will be described. Thereafter, an embodiment of the biological component concentration measuring apparatus according to the present invention will be described.

Ｗ：生体からの熱放射により放射される赤外放射光の放射エネルギー、
ε（λ）：波長λにおける生体の放射率、
Ｗ₀（λ、Ｔ）：波長λ、温度Ｔにおける熱放射の黒体放射強度密度、
ｈ：プランク定数（ｈ＝６．６２５×１０^-34（Ｗ・Ｓ²））、
ｃ：光速（ｃ＝２．９９８×１０¹⁰（ｃｍ／ｓ））、
λ₁、λ₂：生体からの熱放射により放射される赤外放射光の波長（μｍ）、
Ｔ：生体の温度（Ｋ）、
Ｓ：検出面積（ｃｍ²）
ｋ：ボルツマン定数 The radiant energy W of the infrared radiation emitted by the thermal radiation from the living body is expressed by the following mathematical formula.

W: radiant energy of infrared radiation emitted by thermal radiation from a living body,
ε (λ): the emissivity of the living body at the wavelength λ,
W ₀ (λ, T): black body radiation intensity density of thermal radiation at wavelength λ, temperature T,
h: Planck's constant (h = 6.625 × 10 ⁻³⁴ (W · S ² )),
c: speed of light (c = 2.998 × 10 ¹⁰ (cm / s)),
λ ₁ , λ ₂ : wavelength of infrared radiation emitted by thermal radiation from a living body (μm),
T: biological temperature (K),
S: Detection area (cm ² )
k: Boltzmann constant

α（λ）：波長λにおける生体の吸収率 According to (Equation 1), when the detection area S is constant, the radiation energy W of the infrared radiation emitted by the thermal radiation from the living body depends on the emissivity ε (λ) of the living body at the wavelength λ. From Kirchhoff's law of radiation, the emissivity and absorptivity at the same temperature and wavelength are the same.

α (λ): Absorption rate of living body at wavelength λ

ｒ（λ）：波長λにおける生体の反射率
ｔ（λ）：波長λにおける生体の透過率 Therefore, it can be seen that the absorptance should be considered when considering the emissivity. From the law of conservation of energy, the following relationship holds for the absorptance, transmittance, and reflectance.

r (λ): biological reflectance at wavelength λ t (λ): biological transmittance at wavelength λ

Therefore, the emissivity is expressed by the following formula using the transmittance and the reflectance.

Ｉ_t：透過光量、
Ｉ₀：入射光量、
ｄ：生体の厚さ、
ｋ（λ）：波長λにおける生体の消衰係数
生体の消衰係数は、生体による光の吸収を表す。 The transmittance is represented by the ratio between the incident light amount and the transmitted light amount when it passes through the measurement object. The amount of incident light and the amount of light transmitted through the object to be measured are expressed by the Lambert-Beer law.

I _t: the amount of transmitted light,
I ₀ : incident light quantity,
d: thickness of the living body,
k (λ): extinction coefficient of living body at wavelength λ The extinction coefficient of living body represents light absorption by the living body.

Therefore, the transmittance is expressed by the following formula.

ｎ（λ）：波長λにおける生体の屈折率 Next, the reflectance will be described. As the reflectance, it is necessary to calculate an average reflectance in all directions, but here, for simplicity, the reflectance with respect to normal incidence is considered. The reflectance with respect to normal incidence is expressed by the following formula, where the refractive index of air is 1.

n (λ): refractive index of the living body at wavelength λ

From the above, the emissivity is expressed by the following mathematical formula.

  When the concentration of the component in the living body changes, the refractive index and extinction coefficient of the living body change. The reflectance is usually as small as about 0.03 in the infrared region, and, as understood from (Equation 8), does not depend much on the refractive index and the extinction coefficient. Therefore, even if the refractive index and extinction coefficient change due to changes in the concentration of components in the living body, the change in reflectance is small.

  On the other hand, the transmittance greatly depends on the extinction coefficient as shown in (Expression 7). Therefore, the transmittance changes when the extinction coefficient of the living body, that is, the degree of light absorption by the living body, changes due to the concentration change of the components in the living body.

  Therefore, it can be seen that the radiant energy of the infrared radiation emitted by the thermal radiation from the living body depends on the concentration of the component in the living body. The concentration of the component in the living body can be obtained from the radiant energy intensity of the infrared radiation emitted by the thermal radiation from the living body.

  According to (Equation 7), the transmittance depends on the thickness of the living body. The thinner the living body, the greater the degree of change in the transmittance with respect to the change in the extinction coefficient of the living body, making it easier to detect changes in the concentration of components in the living body.

  The eardrum has a thin thickness of about 60 to 100 μm. Therefore, the infrared light emitted from the eardrum is suitable for measuring the concentration of components in the living body.

(Embodiment 1)
Next, the functional configuration of the biological component concentration measuring apparatus of the present invention based on the above principle will be described with reference to FIG.

  FIG. 1 is a perspective view showing an appearance of a biological component concentration measuring apparatus 100 according to the present invention.

  The biological component concentration measuring apparatus 100 (hereinafter referred to as “measuring apparatus 100”) includes a main body 102 and an insertion portion 105 provided on a side surface of the main body 102.

  The main body 102 is provided with a display 114 for displaying the measurement result of the concentration of the biological component, a power switch 101 for turning on / off the power of the measuring apparatus 100, and a measurement start switch 103 for starting the measurement. ing. The display 114 is a liquid crystal display, an organic electroluminescence (EL) display, or the like.

  The insertion portion 105 is a portion that is inserted into the ear hole, and a light guide tube 104 is provided inside the insertion portion 105. When inserted into the ear canal, the light guide tube 104 propagates infrared light incident on the opening that opens into the ear canal and outputs it from the other opening inside the main body 102. The light guide tube 104 only needs to be capable of guiding infrared rays. For example, a hollow tube or an optical fiber that transmits infrared rays can be used. When using a hollow tube, it is preferable to have a gold layer on the inner surface of the hollow tube. This gold layer can be formed by performing gold plating on the inner surface of the hollow tube or by depositing gold.

  Next, the structure inside the main body of the biological component concentration measuring apparatus 100 will be described with reference to FIGS.

  FIG. 2 is a diagram illustrating a configuration of the measurement apparatus 100 according to the present embodiment.

  The main body 102 includes a chopper 118, an infrared detector 108, an optical path cover 120, a preamplifier 130, a band filter 132, a synchronous demodulator 134, a low pass filter 136, and an analog / digital converter (hereinafter abbreviated as A / D converter) 138. A microcomputer 110, a memory 112, a display 114, a power source 116, a timer 156, and a buzzer 158.

  The measuring apparatus 100 detects the infrared light emitted from the eardrum 202 and guided by the light guide tube 104 by the infrared detector 108. Based on the detected infrared light, the microcomputer 110 calculates the concentration of the biological component. Examples of the calculated biological component concentration include glucose concentration (blood glucose level), hemoglobin concentration, cholesterol concentration, and neutral fat concentration.

  In this specification, “infrared light emitted from the eardrum 202” means infrared light emitted from the eardrum 202 due to thermal radiation of the eardrum 202 itself and infrared light irradiated to the eardrum 202. Infrared light radiated from the eardrum 202 is included by being reflected at.

  The measurement apparatus 100 according to the present embodiment does not include a light source that emits infrared light, unlike the measurement apparatus according to the third embodiment described later. Therefore, the infrared detector 108 according to the present embodiment detects infrared light emitted by thermal radiation from the eardrum 202 itself.

  It should be noted that not only the infrared light emitted from the eardrum 202 but also the infrared light emitted from the ear canal 204 or the like is incident on the light guide tube 104, and the light guide tube 104 propagates them. .

  One of the main features of the measuring apparatus 100 according to the present embodiment is that infrared light emitted from the eardrum 202 can be detected from infrared light propagated through the light guide tube 104. For this purpose, an optical path cover 120 and a light scattering portion 404 (described later in FIG. 6) are provided.

  The infrared detector 108 is disposed with a gap from the opening of the light guide tube 104 opened in the main body 102. The optical path cover 120 is provided so as to cover the gap, and has an inner diameter larger than the outer diameter of the infrared detector 108. By letting infrared light from the external auditory canal 204 escape from the gap, the infrared detector 108 can prevent direct detection of infrared light from the external auditory canal 204 that becomes noise.

  Further, infrared light that escapes from the air gap may be reflected inside the main body 102 and may enter the infrared detector 108 as a result. Therefore, infrared light reflected inside the main body 102 is scattered by the light scattering unit, and the intensity of the reflected infrared light incident on the infrared detector 108 can be greatly reduced.

  Hereinafter, components provided in the main body 102 will be described.

  The power source 116 supplies AC or DC power to the microcomputer 110. A battery is preferably used as the power source 116.

  The chopper 118 has a function of chopping infrared light emitted from the eardrum 202 and guided into the main body 102 by the light guide tube 104 to convert the infrared light into a high-frequency infrared signal. The operation of the chopper 118 is controlled based on a control signal from the microcomputer 110. A part of the infrared light chopped by the chopper 118 directly enters the infrared detector 108, and the rest passes through the space between the infrared detector 108 and an optical path cover 120 described later and travels inside the main body 102.

  The infrared detector 108 detects a part of the chopped infrared light.

  FIG. 3 shows the configuration of the infrared detector 108. The infrared detector 108 includes a detection region 126 that detects infrared light. The detection area 126 includes a first detection area 126 (a) and a second detection area 126 (b). The infrared light that has passed through the first optical filter 128 (a) is incident on the first detection region 126 (a), and the infrared light that has passed through the second optical filter 128 (b) is the second detection region. 126 (b). The optical filters 128 (a) and 128 (b) separate infrared light into different wavelengths.

  The infrared light that has reached the first detection region 126 (a) and the second detection region 126 (b) is converted into an electrical signal corresponding to the intensity of the incident infrared light by each detection region and output. Is done.

  The first optical filter 128 (a), for example, has a spectral characteristic that transmits infrared light in a wavelength band (hereinafter, abbreviated as a measurement wavelength band) that includes a wavelength that is absorbed by a biological component that is a measurement target. Have On the other hand, the second optical filter 128 (b) has a spectral characteristic different from that of the first optical filter 128 (a). The second optical filter 128 (b) is, for example, a wavelength band (hereinafter, referred to as a wavelength band including a wavelength that is not absorbed by a biological component that is a measurement target and that is absorbed by another biological component that interferes with the measurement of the target component). It has a spectral characteristic that transmits infrared light (abbreviated as a reference wavelength band). Here, as such other biological components, those having a large amount of components in the living body other than the biological component to be measured may be selected.

  For example, glucose exhibits an infrared absorption spectrum having an absorption peak near 9.6 micrometers. Therefore, when the biological component to be measured is glucose, it is preferable that the first optical filter 128 (a) has a spectral characteristic that transmits infrared light in a wavelength band including 9.6 micrometers. .

  On the other hand, proteins that are abundant in the living body absorb infrared light near 8.5 micrometers, and glucose does not absorb infrared light near 8.5 micrometers. Therefore, it is preferable that the second optical filter 128 (b) has a spectral characteristic that transmits infrared light in a wavelength band including 8.5 micrometers.

As a method for producing the optical filter, a known technique can be used without any particular limitation. For example, the optical filter can be manufactured using a vacuum deposition method or an ion sputtering method. The optical filter can be manufactured by stacking ZnS, MgF ₂ , PbTe, Ge, ZnSe or the like on the substrate by using a vacuum deposition method with Si, Ge, or ZnSe as the substrate.

  Here, an optical filter having a desired wavelength characteristic is manufactured by controlling the light interference in the laminated thin film by adjusting the film thickness of each layer laminated on the substrate, the order of lamination, the number of laminations, and the like. can do.

  Refer to FIG. 2 again. The electrical signal output from the infrared detector 108 is amplified by the preamplifier 130. The amplified electric signal is removed by the band filter 132 from signals other than the frequency band having the chopping frequency as the center frequency. Thereby, noise resulting from statistical fluctuations such as thermal noise can be minimized.

  The electric signal filtered by the band filter 132 is demodulated into a DC signal by synchronizing and integrating the chopping frequency of the chopper 118 and the electric signal filtered by the band filter 132 by the synchronous demodulator 134.

  The electric signal demodulated by the synchronous demodulator 134 is removed from the high frequency band signal by the low-pass filter 136. Thereby, noise can be further removed.

  The electrical signal filtered by the low-pass filter 136 is converted into a digital signal by the A / D converter 138 and then input to the microcomputer 110.

  In the memory 112, an electrical signal corresponding to the intensity of infrared light reaching the first detection area 126 (a) and an electrical signal corresponding to the intensity of infrared light reaching the second detection area 126 (b) Correlation data indicating the correlation between the concentration of the biological component and the biological component is stored. The microcomputer 110 reads the correlation data from the memory 112, refers to the correlation data, and converts the digital signal per unit time calculated from the digital signal stored in the memory 112 into the concentration of the biological component.

  The concentration of the biological component converted in the microcomputer 110 is output to the display 114 and displayed.

  The electric signal corresponding to the intensity of the infrared light transmitted through the first optical filter 128 (a) and the intensity of the infrared light transmitted through the second optical filter 128 (b) stored in the memory 112 Correlation data indicating the correlation between the electrical signal corresponding to and the concentration of the biological component can be obtained, for example, by the following procedure.

  First, infrared light emitted from the eardrum 202 by thermal radiation is measured for a patient having a known biological component concentration (for example, blood glucose level). At this time, the electrical signal corresponding to the intensity of the infrared light in the wavelength band transmitted by the first optical filter 128 (a) and the intensity of the infrared light in the wavelength band transmitted by the second optical filter 128 (b). And an electric signal corresponding to. By performing this measurement on a plurality of patients having different biological component concentrations, the electrical signal corresponding to the intensity of infrared light in the wavelength band transmitted by the first optical filter 128 (a) and the second optical filter 128 are used. It is possible to obtain a data set consisting of an electrical signal corresponding to the intensity of infrared light in the wavelength band transmitted by (b) and the corresponding biological component concentration.

  Next, the data set thus obtained is analyzed to obtain correlation data. For example, the electrical signal corresponding to the intensity of infrared light in the wavelength band transmitted by the first optical filter 128 (a) and the intensity of infrared light in the wavelength band transmitted by the second optical filter 128 (b). Multivariate analysis is performed on the corresponding electrical signals and the corresponding biological component concentrations using a multiple regression analysis method such as a PLS (Partial Least Squares Regression) method or a neural network method. As a result, the electrical signal corresponding to the intensity of infrared light in the wavelength band transmitted by the first optical filter 128 (a) and the intensity of infrared light in the wavelength band transmitted by the second optical filter 128 (b) are obtained. A function indicating the correlation between the corresponding electrical signals and the corresponding biological component concentrations can be obtained.

  The first optical filter 128 (a) has a spectral characteristic that allows infrared light in the measurement wavelength band to pass therethrough, and the second optical filter 128 (b) transmits infrared light in the reference wavelength band. When having spectral characteristics that allow transmission, the electrical signal corresponding to the intensity of infrared light in the wavelength band transmitted by the first optical filter 128 (a) and the wavelength transmitted by the first optical filter 128 (a) A difference from an electrical signal corresponding to the intensity of infrared light in the band may be obtained, and correlation data indicating a correlation between the difference and the corresponding biological component concentration may be obtained. For example, it can be obtained by performing a linear regression analysis such as a least square method.

  Next, a configuration for substantially detecting only the infrared light emitted from the eardrum 202 will be described.

  Infrared light radiated from the eardrum 202 enters the light guide tube 104 substantially parallel to the light guide tube 104 or at a sufficiently small angle. On the other hand, most of the infrared light emitted from the external auditory canal 204 enters the light guide tube 104 at a relatively large incident angle with respect to the light guide tube 104. This is because the position of the ear canal 204 is closer to the light guide tube 104 than the position of the eardrum 202.

  In the light guide tube 104, infrared light propagates while being reflected. Therefore, the infrared light incident on the light guide tube 104 is emitted from the opening (emission end surface) of the light guide tube 104 that opens in the main body 102 at an emission angle that is the same as the incident angle. That is, the infrared light emitted from the eardrum 202 is emitted substantially parallel to the light guide tube 104, and the infrared light emitted from the ear canal 204 is emitted at a large emission angle similar to the incident angle.

  In the present invention, an optical path cover 120 having a shape that takes this difference into consideration is provided.

  FIG. 4 is an enlarged cross-sectional view of the optical path cover 120 according to the present embodiment. The optical path cover 120 covers a space between the opening of the light guide tube 104 (FIG. 2) that opens in the main body 102 and the infrared detector 108. FIG. 4 shows a chopper 118 provided at the opening of the light guide tube 104.

  The inner surface of the optical path cover 120 is configured to have a high reflectance with respect to infrared light. The inner surface of the optical path cover 120 is preferably formed of a material having a reflectance of 90% or more with respect to infrared light. More preferably, it is made of a material having a reflectance of 95% or more with respect to infrared light. In order to give the inner surface of the optical path cover 120 a high reflectance with respect to infrared light, for example, the optical path cover 120 is processed and polished with SUS304. Then, it implement | achieves by providing nickel plating and also providing gold plating from it.

  The inner diameter L2 of the optical path cover 120 is set larger than the outer diameter L1 of the infrared detector 108. With this configuration, a gap is formed between the optical path cover 120 and the infrared detector 108 through which infrared light from the external auditory canal 204 (FIG. 2) can pass. By letting infrared light from the external auditory canal 204 escape from the gap, it is possible to prevent the infrared light emitted from the external auditory canal 204 from directly entering the infrared detector 108.

  When the infrared detector 108 is positioned in the opening 121 of the optical path cover 120 (within the range P in the cross section of the optical path cover 120), the outer diameter L1 of the infrared detector 108 and the inner diameter L2 of the optical path cover 120 are as illustrated. And measured on a plane 151 perpendicular to the axis 150 of the light guide tube. A gap between the optical path cover 120 and the infrared detector 108 (hereinafter simply referred to as “gap”) is defined as a space between the outer diameter L1 of the infrared detector 108 and the inner diameter L2 of the optical path cover 120. .

  FIG. 5 is a perspective view showing a three-dimensional shape of the optical path cover 120.

  The optical path cover 120 is set to have a shape in which the inner surface is cut off from a conical tip. The inner diameter of the end portion of the optical path cover opening is configured to be larger than the outer diameter of the infrared detector 108. However, for convenience of understanding the shape, the infrared detector 108 is described away from the opening of the optical path cover 120. is doing.

  FIG. 6 is a cross-sectional view showing a physical configuration inside the housing of the measuring apparatus 100.

  Inside the housing, an electric circuit board 400, a light reflecting portion 402, and a light scattering portion 404 are provided.

  The electric circuit board 400 includes an infrared detector 108, a microcomputer 110, a memory 112, a display 114, a preamplifier 130, a band filter 132, a synchronous demodulator 134, a low pass filter 136, and an A / D converter shown in FIG. 138, a timer 156, a buzzer 158, and the like are mounted.

  At the position of the electric circuit board 400 on which the infrared detector 108 is mounted, a light reflecting portion 402 having a taper with a predetermined inclination angle (for example, 45 degrees) is provided. The light reflecting portion 402 is set in a shape such that the tip of the cone is cut off, and a mirror surface is provided on the side surface so as to improve the reflectance of infrared light.

  In addition, a light scattering unit 404 is formed on a part of the inner surface of the measuring apparatus 100 at a position where the infrared light from the external auditory canal 204 is reflected by the light reflecting unit 402.

  The infrared light that has reached the light scattering portion 404 is scattered by the light scattering portion 404. Thereby, it is possible to reduce the amount of infrared light radiated from the ear canal 204 that returns to the light reflection unit 402 again, is reflected by the optical path cover 120, and is incident on the infrared detector 108.

  The light scattering unit 404 can use a known technique without any particular limitation. For example, the surface is processed by blasting, and a metal plate having a rough surface is attached to the housing, or directly the housing. This is realized by blasting the inside and processing the inside of the housing into a rough surface.

  A part of the infrared light escaped from the gap is directly reflected by the light reflecting portion 402, and the infrared light escaped from the remaining gap is reflected by the optical path cover 120 and reflected again by the light reflecting portion 402. Is done. The reflected infrared light strikes the light scattering portion 404 provided in the housing and is scattered. When the infrared light is scattered and reflected in the housing, the amount of the infrared light that has escaped from the air gap and enters the infrared detector 108 can be greatly reduced.

  Next, the operation of the biological component concentration measuring apparatus 100 in this embodiment will be described.

  First, when the user presses the power switch 101 of the biological component concentration measuring apparatus 100, the power supply in the main body 102 is turned on, and the biological component concentration measuring apparatus 100 is in a measurement preparation state.

  Next, the user holds the main body 102 and inserts the light guide tube 104 into the ear hole 200. The insertion portion 105 has a conical shape whose diameter increases from the distal end portion of the light guide tube 104 toward the connection portion with the main body 102. The light guide tube 104 is not inserted beyond the position where the outer diameter of the light guide tube 104 is equal to the inner diameter of the ear hole 200.

  Next, when the user presses the measurement start switch 103 of the biological component concentration measuring apparatus 100 while holding the biological component concentration measuring apparatus 100 at a position where the outer diameter of the light guide tube 104 is equal to the inner diameter of the ear hole 200, Measurement starts.

  Infrared light emitted from the eardrum 202 is detected through the light guide tube 104 provided in the insertion portion 105. When the microcomputer 110 determines that a fixed time has elapsed from the start of measurement based on the time signal from the timer 156, the microcomputer 110 controls the chopper 118 to block infrared light reaching the infrared detector 108. As a result, the measurement automatically ends.

  At this time, the microcomputer 110 controls the display 114 and the buzzer 158 to display a message indicating that the measurement is completed on the display 114, to sound the buzzer 158, and to output the sound from a speaker (not shown). To notify the user that the measurement is completed. As a result, the user can confirm that the measurement has been completed, so the light guide tube 104 is taken out of the ear hole 200.

  The microcomputer 110 identifies the electrical signal output from the A / D converter 138 for each detection region by the above-described method, and calculates the average value of the electrical signal corresponding to each detection region.

  Next, the microcomputer 110 transmits the electrical signal corresponding to the intensity of the infrared light transmitted through the first optical filter 128 (a) and the infrared light transmitted through the second optical filter 128 (b) from the memory 112. Correlation data indicating the correlation between the electrical signal corresponding to the intensity of the light and the concentration of the biological component is read out, and the correlation data is referenced to correspond to the intensity of the infrared light transmitted through the first optical filter 128 (a). The electrical signal corresponding to the intensity of the infrared light transmitted through the electrical signal and the second optical filter 128 (b) is converted into the concentration of the biological component. The obtained concentration of the biological component is displayed on the display 114.

  According to the measuring apparatus 100 according to the present embodiment, the inner diameter of the optical path cover 120 is configured to be larger than the outer diameter of the infrared detector 108, and the infrared light is released from the gap between the optical path cover 120 and the infrared detector 108. . Furthermore, the escaped infrared light is scattered by the light scattering unit 404. The amount of the infrared light from the ear canal 202 entering the detector can be reduced, and noise in the measurement can be reduced, so that the measurement accuracy can be improved.

(Embodiment 2)
FIG. 7 is a diagram showing a configuration of the measuring apparatus 100 according to the present embodiment.

  The difference between the measuring apparatus 100 according to the present embodiment and the measuring apparatus according to the first embodiment is that the shape of the inner surface of the optical path cover is an aspherical surface, specifically a parabolic surface. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

  The optical path cover 123 has a focal point 122 by configuring the optical path cover 123 in a parabolic shape. The focal point 122 is set at the center of the emission end of the light guide tube 104 on the infrared detector 108 side. Thereby, most of the infrared light from the external auditory canal 202 emitted from the light guide tube 104 becomes parallel light when reflected by the optical path cover 123. This is because when light emitted from the focal point of the paraboloid is reflected by the paraboloid, it is converted into parallel light.

  It is preferable that the light be parallel light because it is very easy to handle. Infrared light emitted from the external auditory canal 204 converted into parallel light can escape from the gap between the infrared detector 108 and the optical path cover 123.

  Next, with reference to FIG. 8, the internal arrangement of the main body of the measuring apparatus 100 according to the present embodiment and the infrared light from the ear canal 204 that has escaped from the air gap will be described.

  FIG. 8 is a cross-sectional view showing the internal arrangement of the main body according to the present embodiment. An electric circuit board 400 is held inside the housing. The electric circuit board 400 includes the infrared detector 108, the microcomputer 110, the memory 112, the display 114, the preamplifier 130, the band filter 132, the synchronous demodulator 134, the low pass filter 136, and the A / D converter shown in FIG. 138, a timer 156, a buzzer 158, and the like are mounted.

  As in the first embodiment, a light reflecting portion 402 having a 45-degree taper is formed at the position of the electric circuit board 400 on which the infrared detector 108 is mounted. Most of the infrared light from the external auditory canal 204 emitted from the light guide tube 104 is reflected by the optical path cover 123 to become parallel light, and therefore enters the light scattering unit 404 substantially vertically. Thereby, the light scattering unit 404 can efficiently scatter infrared light. Therefore, the amount of infrared light radiated from the ear canal 204 that returns to the light reflecting portion 402 again, is reflected by the optical path cover 123, and enters the infrared detector 108 can be greatly reduced.

  Next, a modification of the measuring apparatus 100 according to the present embodiment will be described with reference to FIG.

  FIG. 9 is a cross-sectional view showing an internal physical configuration of the measuring apparatus 100 according to a modification of the present embodiment. The difference from the measurement apparatus of FIG. 8 is that the infrared detector 108 has one detection region 126 and that the infrared light is dispersed by an optical filter wheel. 8 and 9, the same optical path cover 123 is used, but the length of the optical path cover 123 in the traveling direction of infrared light may be shortened by providing an optical filter wheel. .

  FIG. 10 is a perspective view showing the optical filter wheel 106. The optical filter wheel 106 includes a first optical filter 128 (a) and a second optical filter 128 (b), and these are fitted into a ring 127. Each of the first and second optical filters 128 (a) and 128 (b) functions as a spectroscopic element.

  In the example shown in FIG. 10, the first optical filter 128 (a) and the second optical filter 128 (b), both of which are disk-shaped, are fitted into the ring 127 to form a propeller-shaped member. A shaft 125 is provided at the center of the propeller-like member. By rotating the shaft 125 in the direction of the arrow in FIG. 10, the optical filters through which the infrared light chopped by the chopper 118 passes are changed into the first optical filter 128 (a) and the second optical filter 128 (b ).

  The rotation of the shaft 125 is controlled by a control signal from the microcomputer 110. The rotation of the shaft 125 is preferably synchronized with the rotation of the chopper 118 and controlled to rotate the shaft 125 180 degrees while the chopper 118 is closed. Thereby, when the chopper 118 is opened next, the optical filter through which the infrared light chopped by the chopper 118 passes can be switched to another optical filter.

  When the optical filter wheel 106 is used, it is difficult to arrange the infrared detector 108 in the opening 121 of the optical path cover 123 as shown in FIG. That is, the optical path cover 123 is provided so as to cover a part of the space between the opening of the light guide tube 104 opened in the main body 102 and the infrared detector 108.

  Hereinafter, the meaning of “an optical path cover having an inner diameter larger than the outer diameter of the detector” in the present embodiment will be described with reference to FIG.

  FIG. 11 is an enlarged cross-sectional view of the optical path cover 123 according to the present embodiment.

  When the infrared detector 108 is located in a range outside the opening 121 of the optical path cover 123 (range P in the cross section of the optical path cover 123), the inner diameter L2 of the optical path cover 123 is set as the inner diameter L2 of the opening end of the optical path cover 123. Yes. Since there is always a gap between the optical path cover 123 and the infrared detector 108, infrared light (infrared light from the external auditory canal 204) that is not directly incident on the infrared detector 108 passes from the gap to the outside of the optical path cover 123. To escape. Therefore, it is possible to prevent the infrared light emitted from the ear canal 204 from directly entering the infrared detector 108.

(Embodiment 3)
FIG. 12 is a diagram illustrating a configuration of the measurement apparatus 100 according to the present embodiment.

  The difference between the measuring device 100 according to the present embodiment and the measuring device according to the second embodiment (FIG. 7) is that the measuring device 100 according to the present embodiment includes the second light guide tube 107 and the first half inside the main body 102. The mirror 142, the second half mirror 144, the image sensor 320, the lens 312, and the light source 310 are provided. Since other configurations are the same as those of the second embodiment, description thereof is omitted.

  The second light guide tube 107 is provided to guide the emitted light from the light guide tube 104 to the outside from the end portion of the optical path cover 123. The second light guide tube 107 may be made of the same material as the light guide tube 104 or may be made of another material.

  The inner diameter of the second light guide tube 107 is preferably larger than the inner diameter of the light guide tube 104 in consideration of the spread of infrared light from the eardrum 202 emitted from the light guide tube 104. Further, the inner diameter of the optical path cover 123 is larger than the outer diameter of the second light guide tube 107. Also in this embodiment, the meaning of “optical path cover having an inner diameter larger than the outer diameter of the second light guide tube” means that the detector in the description of the first embodiment (FIG. 4) is used as the second light guide tube. It is the same as the replaced content.

The first half mirror 142 transmits part of visible light and reflects the rest. The second half mirror 144 transmits infrared light emitted from the eardrum 202 and reflects visible light. The material of the second half mirror 144 is preferably a material that does not absorb infrared light, transmits it, and reflects visible light. As a material of the second half mirror 144, for example, ZnSe, CaF ₂ , Si, Ge, or the like can be used.

  The image sensor 320 images the state of the ear canal. The lens 312 forms an image on the image sensor 320. The light source 310 is used to illuminate the eardrum 202.

  By providing the second light guide tube 107, the infrared light emitted from the light guide tube 104 can be guided to the outside from the terminal portion of the optical path cover 123. Thereby, an imaging optical system can be provided. When the imaging optical system is provided, infrared light from the eardrum 202 can be measured while observing the eardrum 202 and confirming that the distal end of the insertion portion 105 faces the eardrum 202, which is preferable because operability is improved. is there.

  On the other hand, visible light that has entered the light guide tube 104 from the eardrum 202 through the ear canal 204 is reflected by the second half mirror 144, and part of the visible light passes through the first half mirror 142. Visible light transmitted through the first half mirror 142 is collected by the condenser lens 312 held by the lens frame 322 and reaches the image sensor 320.

  As the image sensor 320, for example, an image element such as a CMOS or a CCD is used.

  In addition, an actuator may be provided in the lens frame in order to optimize the imaging state of the image of the eardrum 202 by driving a lens frame (not shown). This is preferable because an optimal image of the eardrum 202 can be obtained even when the insertion state into the ear canal changes.

  Of the infrared light emitted from the light guide tube 104 to the optical path cover 123 side, the infrared light that has not passed through the second light guide tube 107 does not directly enter the infrared detector 108 and enters the inside of the main body 102. move on. Since the infrared light is scattered by a light scattering portion 404 (for example, FIG. 8) provided in the main body 102, the intensity incident on the infrared detector 108 can be greatly reduced.

  Therefore, noise in measurement can be reduced and measurement accuracy can be improved. Furthermore, since measurement can be performed while confirming that the insertion portion 105 is directed in the direction of the eardrum 202 by performing measurement while imaging the eardrum 202, measurement accuracy can be improved.

(Embodiment 4)
FIG. 13 is a diagram illustrating a configuration of the measurement apparatus 100 according to the present embodiment.

  The difference between the measuring apparatus 100 according to the present embodiment and the measuring apparatus according to the second embodiment (FIG. 7) is that the measuring apparatus 100 according to the present embodiment radiates the second light guide tube 107 and infrared rays inside the main body 102. The infrared light source 700 and the half mirror 702 are provided. Since other configurations are the same as those of the second embodiment, description thereof is omitted.

  By providing the second light guide tube 107, the infrared light emitted from the light guide tube 104 can be guided to the outside from the terminal portion of the optical path cover 120. Thereby, the infrared light source 700 and the half mirror 702 can be provided like this embodiment.

  The infrared light source 700 emits infrared light for irradiating the eardrum 202 with infrared light. The infrared light emitted from the infrared light source 700 and reflected by the half mirror 702 is guided into the ear canal 204 through the second light guide tube 107 and the light guide tube 104 and irradiates the eardrum 202.

  The infrared light that has reached the eardrum 202 is reflected by the eardrum 202 and the external auditory canal 204, and is emitted as reflected light to the biological component concentration measuring apparatus 100 side. This infrared light again passes through the light guide tube 104, the second light guide tube 107, and the half mirror 702, and is detected by the infrared detector 108.

  Most of the infrared light from the external auditory canal 204 is present in the vicinity of the light guide tube 104 compared to the eardrum 202, so that the outer ear canal 204 has a large incident angle with respect to the light guide tube 104. Incident. In the light guide tube 104, infrared light propagates while being reflected. Therefore, the infrared light incident on the light guide tube 104 is emitted from the opening (emission end surface) of the light guide tube 104 that opens in the main body 102 at an emission angle that is the same as the incident angle.

  The inner diameter of the optical path cover 123 is set larger than the outer diameter of the second light guide tube 107. In the present embodiment, “the optical path cover having an inner diameter larger than the outer diameter of the second light guide tube” means that the detector in the description of the first embodiment (FIG. 4) is replaced with the second light guide tube. Same as the contents. Since an air gap through which infrared light from the external auditory canal 204 can pass is formed between the optical path cover and the second light guide tube, the infrared light from the external ear canal 204 can escape from the air gap. Thereby, the infrared light emitted from the ear canal 204 incident on the infrared detector 108 can be reduced.

  The intensity of the reflected light from the eardrum 202 detected by the measurement apparatus 100 according to the present embodiment is represented by the product of the reflectance expressed by (Equation 8) and the intensity of infrared light applied to the eardrum 202. As shown in (Equation 8), when the concentration of the component in the living body changes, the refractive index and extinction coefficient of the living body change. The reflectance is usually as small as about 0.03 in the infrared region, and according to (Equation 8), it does not depend much on the refractive index and the extinction coefficient, and the reflectance due to changes in the concentration of components in the living body. The change is small. However, it can be detected by increasing the intensity of infrared rays emitted from the infrared light source 700.

  As the infrared light source 700, a known one can be applied without any particular limitation. For example, a silicon carbide light source, a ceramic light source, an infrared LED, a quantum cascade laser, or the like can be used.

The half mirror 702 has a function of dividing infrared light into two light beams. As a material of the half mirror 702, for example, ZnSe, CaF ₂ , Si, Ge, or the like can be used. Furthermore, it is preferable that an antireflection film is formed on the half mirror 702 for the purpose of controlling infrared transmittance and reflectance.

  In the memory 112, an electric signal corresponding to the intensity of the infrared light transmitted through the first optical filter 128 (a) shown in FIG. 3 and the intensity of the infrared light transmitted through the second optical filter 128 (b). A plurality of correlation data indicating the correlation between the electrical signal corresponding to the above and the concentration of the biological component is stored.

  The electric signal corresponding to the intensity of the infrared light transmitted through the first optical filter 128 (a) and the intensity of the infrared light transmitted through the second optical filter 128 (b) stored in the memory 112 Correlation data indicating the correlation between the electrical signal corresponding to and the concentration of the biological component can be obtained, for example, by the following procedure.

  First, with respect to a patient having a known biological component concentration (for example, blood sugar level), infrared light emitted from the eardrum 202 is reflected by the infrared light irradiated to the eardrum 202 from the infrared light source 700. taking measurement. At this time, the electrical signal corresponding to the intensity of the infrared light in the wavelength band transmitted by the first optical filter 128 (a) and the intensity of the infrared light in the wavelength band transmitted by the second optical filter 128 (b). And an electric signal corresponding to. By performing this measurement on a plurality of patients having different biological component concentrations, the electrical signal corresponding to the intensity of infrared light in the wavelength band transmitted by the first optical filter 128 (a) and the second optical filter 128 ( It is possible to obtain a data set consisting of an electrical signal corresponding to the intensity of infrared light in the wavelength band transmitted by b) and a biological component concentration corresponding to the electrical signal.

  Correlation data is obtained by analyzing the data set thus obtained in the same manner as in the first embodiment. Specifically, an electrical signal corresponding to the intensity of infrared light in the wavelength band transmitted by the first optical filter 128 (a) and infrared light in the wavelength band transmitted by the second optical filter 128 (b). A multivariate analysis is performed on the electrical signal corresponding to the intensity of the light and the concentration of the biological component corresponding thereto using a multiple regression analysis method such as a PLS (Partial Least Squares Regression) method or a neural network method. Thereby, for each group, the electrical signal corresponding to the intensity of the infrared light in the wavelength band transmitted by the first optical filter 128 (a) and the infrared signal in the wavelength band transmitted by the second optical filter 128 (b). A function indicating the correlation between the electrical signal corresponding to the intensity of light and the corresponding biological component concentration can be obtained.

  The infrared light emitted from the infrared light source 700 to the eardrum 202 is reflected by the eardrum 202, so that the infrared detector 108 detects infrared light emitted from the eardrum 202. Thereby, it is possible to measure a biological component density | concentration.

  Next, the operation of the biological component concentration measuring apparatus 100 according to the present embodiment will be described.

  First, when the user presses the power switch 101 of the biological component concentration measuring apparatus 100, the power supply in the main body 102 is turned on, and the biological component concentration measuring apparatus 100 is in a measurement preparation state.

  Next, the user holds the main body 102 and inserts the light guide tube 104 into the ear hole 200. The insertion portion 105 has a conical shape whose diameter increases from the distal end portion of the light guide tube 104 toward the connection portion with the main body 102. The light guide tube 104 is not inserted beyond the position where the outer diameter of the light guide tube 104 is equal to the inner diameter of the ear hole 200.

  Next, when the user presses the measurement start switch 103 of the biological component concentration measuring apparatus 100 while holding the biological component concentration measuring apparatus 100 at a position where the outer diameter of the light guide tube 104 is equal to the inner diameter of the ear hole 200, Measurement starts.

  First, infrared light emitted by thermal radiation from the eardrum 202 is measured in a state where the infrared light source 700 is not operating. Next, when the microcomputer 110 determines that a certain time has elapsed from the start of measurement based on a time signal from the timer 156, the microcomputer 110 activates the infrared light source 700. Thereby, in addition to the infrared light radiated by the thermal radiation from the eardrum 202, the infrared light emitted from the infrared light source 700 to the eardrum 202 is reflected by the eardrum 202, thereby the infrared light emitted from the eardrum 202. Light is measured.

  When the microcomputer 110 determines that a certain time has elapsed from the start of measurement based on the time signal from the timer 156, the microcomputer 110 controls the infrared light source 700 to block infrared light. As a result, the measurement automatically ends. At this time, the microcomputer 110 controls the display 114 and the buzzer 158 to display a message indicating that the measurement is completed on the display 114, to sound the buzzer 158, and to output the sound from a speaker (not shown). To notify the user that the measurement is completed. As a result, the user can confirm that the measurement has been completed, so the light guide tube 104 is taken out of the ear hole 200.

  The microcomputer 110 identifies the electrical signal output from the A / D converter 138 for each optical filter by the above-described method, and calculates the average value of the electrical signal corresponding to each optical filter.

  Next, the microcomputer 110 corresponds to the electrical signal corresponding to the intensity of the infrared light transmitted through the first optical filter 128 (a) and the intensity of the infrared light transmitted through the second optical filter 128 (b). Correlation data indicating the correlation between the electrical signal to be performed and the concentration of the biological component is read out. With reference to the correlation data, the electrical signal corresponding to the intensity of the infrared light transmitted through the first optical filter 128 (a) measured in a state where the infrared light source 700 is operated, and the second optical filter The electrical signal corresponding to the intensity of the infrared light transmitted through 128 (b) is converted into the concentration of the biological component. The obtained concentration of the biological component is displayed on the display 114.

  In this embodiment, an example using an infrared light source that emits various wavelengths such as a silicon carbide light source and a ceramic light source has been described. For example, light having a specific wavelength such as an infrared LED or a quantum cascade laser is used. In the case of using an infrared light source that can emit light, it is not necessary to split infrared light. Therefore, the first optical filter 128 (a) and the second optical filter 128 (b) held in the infrared detector 108 according to the present embodiment are not necessary.

  According to the measuring apparatus 100 according to the present embodiment, the infrared light from the external auditory canal 204 enters the infrared detector 108 by making the inner diameter of the optical path cover 120 larger than the outer diameter of the second light guide tube 107. The amount can be reduced. Therefore, measurement accuracy can be improved as a result of reducing noise in measurement. Furthermore, since measurement can be performed while confirming that the insertion portion 105 is directed in the direction of the eardrum 202 by performing measurement while imaging the eardrum 202, measurement accuracy can be improved.

  A light scattering portion made of the same material as the light scattering portion 404 may be provided on the outer surface of the second light guide tube 107 in the above-described third and fourth embodiments.

  The present invention is useful for non-invasive measurement of biological component concentrations, for example, measuring glucose concentration without collecting blood.

1 is a perspective view showing an appearance of a biological component concentration measuring apparatus 100. FIG. It is a figure which shows the structure of the measuring apparatus 100 by Embodiment 1. FIG. The structure of the infrared detector 108 is shown. 2 is an enlarged cross-sectional view of an optical path cover 120 according to Embodiment 1. FIG. 3 is a perspective view showing a three-dimensional shape of an optical path cover 120. FIG. 2 is a cross-sectional view showing a physical configuration inside the measuring apparatus 100. FIG. It is a figure which shows the structure of the measuring apparatus 100 by Embodiment 2. FIG. FIG. 6 is a cross-sectional view illustrating an internal arrangement of a main body according to a second embodiment. FIG. 10 is a cross-sectional view illustrating an internal physical configuration of a measurement apparatus 100 according to a modification of the second embodiment. 2 is a perspective view showing an optical filter wheel 106. FIG. 6 is an enlarged cross-sectional view of an optical path cover 123 according to Embodiment 2. FIG. It is a figure which shows the structure of the measuring apparatus 100 concerning Embodiment 3. FIG. It is a figure which shows the structure of the measuring apparatus 100 concerning Embodiment 4. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Biological-component density | concentration measuring apparatus 104 Light guide tube 105 Insertion part 108 Infrared detector 118 Chopper 120, 123 Optical path cover 121 Optical path cover opening 122 Optical path cover focus 200 Ear hole 202 Tympanic membrane 204 Outer ear canal 400 Electric circuit board 402 Light reflection part 404 Light scattering Part

Claims (9)

An insertion portion provided with a light guide tube that is inserted into the ear hole, and when the light guide tube is inserted into the ear hole, the light guide tube receives infrared light incident on a first opening that opens into the ear hole. An insertion portion that propagates and outputs from the second opening;
A detector that is disposed apart from the second opening and detects a part of the infrared light output from the second opening;
A calculation unit for calculating a concentration of a biological component based on infrared light detected by the detector;
An optical path cover provided to cover at least a part of the space from the second opening to the detector, and having an inner diameter larger than the outer diameter of the detector;
A biological component concentration measuring apparatus comprising: a light scattering unit that scatters and attenuates infrared light that is not incident on the detector.   The measurement apparatus according to claim 1, wherein the light scattering unit scatters infrared light that has passed through a space between an outer diameter of the detector and an inner diameter of the optical path cover. The light guide tube has a linear shape,
The measurement device according to claim 1, wherein the detector is disposed on an extension line of the light guide tube.   The measuring apparatus according to claim 1, wherein an inner surface of the optical path cover is formed of a material having a reflectance equal to or higher than a predetermined reflectance with respect to the infrared light. The light guide tube has a linear shape,
The measuring apparatus according to claim 4, wherein an inner surface of the optical path cover has an aspherical shape.   The measuring apparatus according to claim 5, wherein the aspherical shape is a parabolic shape.   The measuring apparatus according to claim 6, wherein the paraboloid has a focal point adjusted to be located at a center of the second opening.   The arithmetic unit holds data defining correspondence between the detection value of infrared light and the concentration value of a biological component, and refers to the data based on the detection value of infrared light by the detector. The measurement apparatus according to claim 1, wherein the measurement value is specified. An insertion portion provided with a first light guide tube to be inserted into the ear hole, and when inserted into the ear hole, the first light guide tube is incident on a first opening portion that opens into the ear hole. An insertion part for propagating infrared light and outputting it from the second opening;
A detector that is disposed apart from the second opening and detects a part of the infrared light output from the second opening;
A second light guide tube provided between the second opening and the detector;
A calculation unit for calculating a concentration of a biological component based on infrared light detected by the detector;
An optical path cover provided to cover at least a part of the space from the second opening to the detector, and having an inner diameter larger than the outer diameter of the second light guide tube;
A biological component concentration measuring apparatus comprising: a light scattering unit that scatters and attenuates infrared light that is not incident on the second light guide tube.

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