JP2008267919A - Component concentration measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a component concentration measuring apparatus capable of reducing measurement errors and enhancing measurement accuracy. <P>SOLUTION: The component concentration measuring apparatus 100 comprises a standard sample 98 used for calibration; a light-irradiating means 110 for irradiating a measured object 99 and the standard sample 98 with modulated laser beams, obtained by electrically modulating the intensity of laser beams by a modulation signal of specific frequency; a plurality of sound wave detecting means 120, 121 detecting ultrasonic waves from the measured object 99 and the standard sample 98 generated by the irradiated modulated laser beams and outputting them as electrical signals; and a differential amplifier 130 differentially amplifying the electrical signals from the plurality of sound wave detecting means 120, 121. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a non-invasive component concentration measurement apparatus for an object to be measured such as a human being, an animal, or a fruit.

  With the aging of society, dealing with adult diseases is becoming a major issue. In blood glucose level testing, blood collection is necessary, which is a heavy burden on the patient. Therefore, a non-invasive blood component concentration measurement apparatus that does not collect blood has attracted attention. As a non-invasive blood component concentration measuring device developed so far, the skin is irradiated with electromagnetic waves, and the blood component to be measured, for example, in the case of blood glucose level, is absorbed by glucose molecules and heated locally. The photoacoustic method, which observes acoustic waves generated from the living body due to thermal expansion, has attracted attention.

  However, the photoacoustic blood component concentration measurement apparatus has a small interaction between glucose and electromagnetic waves, and there is a limit to the intensity of electromagnetic waves that can be safely irradiated to the living body. It has not been effective.

  FIG. 5 is a configuration example of a conventional blood component concentration measuring apparatus using a photoacoustic method. In the blood component concentration measuring apparatus 80 shown in FIG. 5, the housing 85 stores a drive circuit 81, an acoustic wave detector 82, a pulse light source 83, and a waveform observer 84 (see, for example, Non-Patent Document 1). The opening 86 is formed in the housing 85, and the measurement object 99 is inserted therein. The drive circuit 81 provides a pulsed excitation current to the pulsed light source 83, which generates an optical pulse having a sub-microsecond duration. The light pulse generated by the pulse light source 83 is applied to the object 99 to be measured. The light pulse generates an acoustic wave called a pulsed ultrasonic wave inside the object to be measured 99. The generated acoustic wave is detected by the acoustic wave detector 82 and further converted into an electric signal proportional to the sound pressure.

  The waveform of the converted electric signal is observed by the waveform observer 84. The waveform observer 84 is triggered by a signal synchronized with the excitation current, and the converted electric signal is displayed at a fixed position on the tube surface of the waveform observer 84. The converted electrical signal can be measured by integration and averaging. By analyzing the amplitude of the electrical signal thus obtained, the blood sugar level inside the measurement object 99, that is, the amount of glucose is measured. In the case of the example shown in FIG. 5, an optical pulse having a sub-microsecond pulse width is repeatedly generated at a maximum of 1 kHz, and 1024 optical pulses are averaged to measure the electrical signal.

  FIG. 6 is a diagram illustrating a configuration example of a component concentration measuring apparatus according to a second conventional example (see, for example, Patent Document 1). In this example as well, blood sugar is the main measurement target, and high accuracy is attempted using a plurality of light sources having different wavelengths. In FIG. 6, the excitation light source 92a is intensity-modulated in synchronization with the oscillator 95 by the drive circuit 91a. The excitation light source 92b is intensity-modulated in synchronization with the oscillator 95 by the drive circuit 91b. Here, the output of the oscillator 95 is fed to the drive circuit 91b via the 180 ° phase shifter 94, and as a result, the excitation light source 92b is configured to be modulated in the opposite phase to the excitation light source 92a. Yes. The output lights of the two excitation light sources 92a and 92b are combined by a combiner 96 and applied to the object 99 as a single light beam.

The ultrasonic wave generated by the measurement object 99 is detected by the ultrasonic detector 93 and converted into an electric signal proportional to the sound pressure. The amplitude of the electric signal is measured by the phase detection amplifier 97 synchronized with the oscillator 95 and obtained as an ultrasonic output. In this example, the wavelengths of the output light of the excitation light sources 92a and 92b are the absorption wavelength of water and the absorption wavelength of glucose, and the absorption coefficient of water is equal. By estimating the amount of glucose from the difference between the two ultrasonic waves, the ultrasonic waves generated from the water as background noise in the measurement object 99 are removed.
JP 2005-192611 A University of Oulu (University of Oulu, Finland) thesis “Pulse photoacoustic technique and glucodesis in human blood and tissue” (IBS 951-42-6690-0, ul./200.

  The measurement device has a possibility that the reliability of the measurement value may change due to temperature, electromagnetic noise, and other instability factors of equipment parts. For this reason, a general measuring apparatus has some index that does not change the reliability of the measurement value in order to ensure the reliability of the apparatus itself. The component concentration measuring device assumes continuous measurement and absolute value measurement. In performing continuous measurement, it is possible to measure relative values of measured values. In order to measure the absolute value, an index indicating a zero point at which the measured value does not change is required, and the measured value needs to be calibrated using this index.

  In the component concentration measuring apparatus of the second conventional example, a glass container enclosing water or a glass container enclosing water in which scatterers such as latex particles simulating scattering in the object to be measured are encapsulated is used as a standard sample. Yes. Before the measurement, the standard sample is brought into contact with the ultrasonic detector, and the measured value at that time is made to correspond to the standard value, for example, 0 mg / dl for the glucose concentration, thereby calibrating the component concentration measuring apparatus.

  Examples of the cause of the measurement error include a measurement environment such as a temperature change of an object to be measured or a standard sample, and background noise such as external acoustic noise or electromagnetic noise.

  FIG. 7 shows the relationship between the wavelength of excitation light and the absorbance of water. When the water absorption spectrum changes due to temperature change, the intensity of the ultrasonic wave changes. In the component concentration measuring apparatus of the second conventional example described above, it is necessary to balance two ultrasonic waves for apparatus calibration. FIG. 8 shows the measurement results of signal intensity over time for a standard sample when two waves of ultrasonic waves are balanced at a constant temperature. FIG. 9 shows the measurement results of signal intensity over time for the standard sample when the temperature changes. As shown in FIGS. 8 and 9, the intensity change of the ultrasonic wave accompanying the temperature change breaks the balance of the two ultrasonic waves. Therefore, when performing an accurate measurement, it is necessary to measure the accurate temperatures of the object to be measured and the standard sample, and to perform temperature correction based on the temperature difference between them.

  In the component concentration measuring apparatus of the second conventional example, the measurement object is measured after measuring the standard sample. At this time, it is expected that the measurement environment changes due to the time difference between the measurement of the standard sample and the object to be measured. Changes in the measurement environment become unstable factors in highly accurate temperature measurement. Furthermore, the background noise is expected to change due to the time difference between the measurement of the standard sample and the object to be measured. When performing highly accurate measurement with a signal-to-noise ratio (SN ratio) of 1000 or more, it is necessary to remove background noise.

  It is an object of the present invention to provide a component concentration measuring apparatus that can reduce measurement errors and increase measurement accuracy.

  In order to solve the above-described problems, a component concentration measuring apparatus according to the present invention includes a differential amplifier.

  Specifically, the component concentration measuring apparatus according to the present invention irradiates the measurement object and the standard sample with a standard sample used for calibration and a modulated laser beam obtained by electrically modulating the intensity of the laser beam with a modulation signal having a constant frequency. Irradiating means, a plurality of sound wave detecting means for detecting ultrasonic waves from the object to be measured and the standard sample generated by the irradiated modulated laser light and outputting them as electric signals, and the plurality of sound wave detecting means And a differential amplifier for differentially amplifying the electrical signal from.

  In the component concentration measuring apparatus, the differential amplifier can differentially amplify the electric signal to reduce the influence of background noise, reduce measurement errors, and increase measurement accuracy.

  In the component concentration measuring apparatus according to the present invention, it is preferable that the standard sample is disposed at a position where the object to be measured can contact.

  The component concentration measuring apparatus can bring the temperature of the standard sample and the object to be measured close to each other, and can further reduce measurement errors.

  In the component concentration measuring apparatus according to the present invention, a pressing unit that presses the object to be measured, and a shutter that shields the modulated laser light irradiated to the object to be measured when the modulated laser light is irradiated to the standard sample. It is preferable to further comprise.

  In the component concentration measuring apparatus, the acoustic impedance of the boundary surface between the standard sample and the object to be measured can be kept constant by the pressing means, and the measurement error can be further reduced.

  The component concentration measuring apparatus according to the present invention preferably further includes a heat sink in contact with at least the standard sample and the plurality of sound wave detecting means.

  The component concentration measuring apparatus can reduce temperature changes of the standard sample and the plurality of sound wave detecting means, and can further reduce measurement errors.

  In the component concentration measuring apparatus according to the present invention, it is preferable that at least the standard sample and the plurality of sound wave detecting means are shielded from background noise.

  The above-described component concentration measuring apparatus can reduce the influence of background noise and can further reduce measurement errors.

  In the component concentration measuring apparatus according to the present invention, it is preferable that at least the standard sample and the plurality of sound wave detecting means are insulated.

  The component concentration measuring apparatus can reduce the influence of changes in the measurement environment and can further reduce measurement errors.

  The present invention can provide a component concentration measuring apparatus that can reduce measurement errors and increase measurement accuracy.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiment described below is an example of the configuration of the present invention, and the present invention is not limited to the following embodiment. Further, in the diagram showing the configuration of the component concentration measuring apparatus according to each embodiment, a portion that can be realized by a normal technique such as a power source or a control unit that controls the entire operation is not shown.

  FIG. 1 shows a schematic diagram of a component concentration measuring apparatus according to this embodiment. The component concentration measuring apparatus 100 according to the present embodiment irradiates the measurement object 99 and the standard sample 98 with a standard sample 98 used for calibration and a modulated laser beam obtained by electrically modulating the intensity of the laser beam with a modulation signal having a constant frequency. A light irradiation means 110; a plurality of sound wave detection means 120, 121 for detecting ultrasonic waves from the measured object 99 and the standard sample 98 generated by the irradiated modulated laser light and outputting them as electric signals; and a plurality of sound wave detections And a differential amplifier 130 for differentially amplifying the electric signals from the means 120 and 121. Further, FIG. 1 shows a drive circuit 111, an excitation light source 112, an optical branching device 113, and a shutter 140 as the light irradiation means 110.

  An example of the excitation light source 112 is a semiconductor laser such as a distributed feedback semiconductor laser (DFB-LD). Moreover, it is preferable that the excitation light source 112 can change the wavelength of the laser beam output by heating or cooling with a heater or a Peltier element.

  For example, the drive circuit 111 is connected to the excitation light source 112 and supplies power to the excitation light source 112. The drive circuit 111 modulates the laser light output from the excitation light source 112 at a constant frequency, for example, a frequency of 500 kHz. The modulated laser light modulated by the drive circuit 111 is branched by the optical branching device 113 and irradiated to the object to be measured 99 and the standard sample 98.

  Examples of the optical branching device 113 include a half mirror, an optical planar circuit (PLC), and an optical coupler that equally divide the modulated laser light from the excitation light source 112. Since the optical splitter 113 branches the modulated laser light from the excitation light source 112 to the object 99 and the standard sample 98, the component concentration measuring apparatus 100 does not move the object 99 and the standard sample 98 without moving the object 99 and the standard sample 98. The measured object 99 and the standard sample 98 can be irradiated with modulated laser light.

  Here, the component concentration measuring apparatus 100 preferably transmits the modulated laser beam to an optical fiber (not shown), and an emission port (not shown) formed at the tip of the optical fiber is in close contact with the outer wall surface of the standard sample 98. More preferably. Since the irradiated position (not shown) of the standard sample 98 is not exposed to the outside, the conventionally required cleaning can be eliminated.

  As the shutter 140, for example, there is a small plate that shields the modulated laser light irradiated on the object 99 to be measured.

  The object to be measured 99 generates ultrasonic waves according to the modulation frequency by the irradiated modulated laser light. The sound wave detection means 120 detects the ultrasonic wave generated by the measurement object 99. Further, the standard sample 98 generates ultrasonic waves according to the modulation frequency by the irradiated modulated laser light. The sound wave detection unit 121 detects ultrasonic waves generated in the standard sample 98. The component concentration measuring apparatus 100 may include two or more standard samples 98. In this case, the same number of sound wave detection means 121 as the standard samples 98 may be provided.

  If the standard sample 98 and the object 99 to be measured are arranged apart from each other, the influence of the background noise received by the standard sample 98 and the object 99 to be measured and the measurement environment are different, the calibration accuracy is lowered, and a measurement error is caused. For this reason, in the component concentration measuring apparatus 100 which concerns on this embodiment, it is preferable that the standard sample 98 is arrange | positioned in the position which the to-be-measured object 99 can contact. Furthermore, it is more preferable that the sound wave detection means 121 and the standard sample 98 are arranged at a position where the object to be measured 99 can contact. As a result, the component concentration measuring apparatus 100 can bring the temperature of the standard sample 98 and the object 99 to be measured close to each other, and the influence of the background noise received by the standard sample 98 and the object 99 to be measured becomes substantially equal. It can be further reduced.

  Here, the standard sample 98 and the sound wave detection means 121 may be fixed with an adhesive. The acoustic impedances of the standard sample 98 and the sound wave detecting means 121 are matched, and the calibration accuracy is higher. Further, the standard sample 98 and the sound wave detection means 121 may be integrated (not shown).

  In order to match the acoustic impedance of the standard sample 98 and the sound wave detection means 121, the adhesive preferably has an acoustic impedance between the standard sample 98 and the sound receiving surface of the sound wave detection means 121. The adhesive described above includes, for example, a polymer base material. Examples of the polymer base material include rubber, natural polymer compounds, and synthetic polymer compounds. Here, the polymer is a molecule having a very large molecular weight. Examples of rubber include elastic rubber such as natural rubber and synthetic rubber. Examples of natural polymer compounds include proteins such as gelatin and keratin, and polysaccharide substances such as cellulose and starch. Examples of the synthetic polymer compound include synthetic fibers such as plastic resins, thermosetting resins, and photocurable resins, and synthetic rubbers. Here, the plastic resin is preferably softened by heating to the glass transition temperature or the melting point, and can be molded into a desired shape. Here, softening means that the amorphous material becomes soft, for example, the viscosity becomes 1 to 10 Ns / m by heating. The polymer base material is preferably melted by heating. As such a polymer base material, for example, one having a chain structure by addition polymerization can be used.

  Examples of the plastic resin include acrylic resin (PMMA), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyvinylidene chloride, polystyrene (PS), polyvinyl acetate, fluororesin, Teflon ( There are general-purpose plastics such as (registered trademark) R-polytetrafluoroethylene (PEFE), ABS resin and AS resin. Examples of the plastic resin include polyamide (PA), polyacetal (POM), polycarbonate (PC), modified polyphenylene ether (m-PPE, modified PPE), polybutylene terephthalate (PBT), and glass fiber reinforced polyethylene terephthalate. There are general-purpose engineering plastics such as (GF-PET) and cyclic polyolefin (COP). Furthermore, examples of the plastic resin include super engineering plastics, polyethylene sulfide (PPS), polysulfone (PSF), polyethersulfone (PES), amorphous polyarylate (PAR), liquid crystal polyester (LCP), polyetherketone ( There are also general-purpose engineering plastics such as PEEK and polyimide (PI).

  Examples of the thermosetting resin include epoxy resin, urethane resin (polyurethane), silicon resin (silicone), phenol resin, unsaturated polyester, alkyd resin, urea resin (urea resin), melamine resin, and ionomer.

  As said photocurable resin, there exists a thing containing a photocationic polymerizable compound and a photocationic polymerization initiator, for example. Examples of the photocationically polymerizable compound include compounds having at least one photocationically polymerizable functional group such as an epoxy group, oxetanyl group, hydroxyl group, vinyl ether group, episulfide group, and ethyleneimine group in the molecule. In addition, since the photocuring degree of polymerization is high and photocuring proceeds efficiently with a small amount of light, it is preferable to use a compound having at least one epoxy group in the molecule as the photocurable resin. The property (molecular weight) of these photocationically polymerizable compounds is not particularly limited, and may be any of a monomer, an oligomer, and a polymer. Moreover, these photocationic polymerizable compounds may be used independently and may use 2 or more types together. Further, as the polymer base material, for example, an epoxy resin, a urethane resin, a silicone resin, an acrylic resin, protein, rubber, or a composite material thereof may be used.

  The object to be measured 99 includes a human body or a part of the human body, for example, a finger or an ear. If the measured object 99 is a finger or an ear, the component concentration measuring apparatus 100 can measure the concentrations of glucose and corsterol in the blood. Moreover, as the to-be-measured object 99, there exist also the collection | collection extract | collected from fruit, such as a laboratory rat and a tangerine, a human body, or a laboratory rat, for example. If the measured object 99 is a fruit, the component concentration measuring apparatus 100 can measure the sugar content of the fruit, that is, the sweetness of the fruit.

  As the standard sample 98, for example, there is a sample in which a bio-equivalent material prepared so as to exhibit absorbance, electrothermal characteristics, and acoustic characteristics equivalent to the measurement object 99 is enclosed. If the component to be measured is glucose in the blood, the standard sample 98 includes, for example, a glass cell in which a soft gel sample containing an aqueous solution or water is sealed, or blood or serum whose blood component amount has been tested. In the component concentration measuring device 100 having the glass cell, the component concentration measuring device 100 can be calibrated by using a standard sample corresponding to the component to be measured of the object 99 to be measured.

  For example, the differential amplifier 130 differentially amplifies the electrical signals from the sound wave detection means 120 and 121 and outputs the electrical signals to a phase detector (not shown) connected to the differential amplifier 130. The component concentration measuring apparatus 100 may calculate the component concentration to be measured based on the intensity of the electric signal and output it to an output unit such as a display or a printer. Here, it is preferable that the distance of the wiring from the sound wave detection means 120 to the differential amplifier 130 is substantially equal to the distance of the wiring from the sound wave detection means 121 to the differential amplifier 130 (not shown).

  An example of the procedure of measuring the component concentration using the component concentration measuring apparatus 100 will be shown. First, the component concentration measuring apparatus 100 is calibrated when measuring the component concentration of the measurement object 99. The standard sample 98 is in contact with the measurement object 99, and the temperature of the standard sample 98 and the measurement object 99 is substantially equal. At the time of calibration, that is, when irradiating the standard sample 98 with modulated laser light, the shutter 140 shields the modulated laser light irradiated on the object 99 to be measured. Here, the shutter 140 may be opened when the intensity of the modulated laser beam is stabilized at a predetermined value or less at the time of calibration. The modulated laser light includes two wavelengths of light that are equally absorbed by the object to be measured 99, and each light is subjected to antiphase modulation. The modulated laser beam is applied to the standard sample 98 through the optical branching unit 130. In the standard sample 98, two waves of antiphase are generated by two wavelengths of light included in each modulated laser beam. Here, the component concentration measuring apparatus 100 adjusts and calibrates the modulated laser light so that the two ultrasonic waves overlap and cancel each other.

  Next, the component concentration of the measurement object 99 is measured. When measuring the component concentration, that is, when irradiating the measured object 99 with modulated laser light, the shutter 140 is opened so as not to shield the modulated laser light irradiated to the measured object 99. The modulated laser beam is branched into two through an optical branching unit 130. One of the two-branched modulated laser light passes through the open shutter 140 and irradiates the measurement object 99. The other of the two branched modulated laser beams is irradiated to the standard sample 98.

  Since the electrical signal from the standard sample 98 has been calibrated, only the background noise is present. The electrical signal from the device under test 99 includes an electrical signal of a component to be measured included in the device under test 99 and background noise. Here, the background noise is mainly acoustic noise and electromagnetic noise. The wavelength of these background noises is considered to be sufficiently longer than the distance between the two sound wave detection means 120, 121. Electrical signals from the device under test 99 and the standard sample 98 are input to the differential amplifier 130. Since the background noise included in the electric signals from the DUT 99 and the standard sample 98 has the same phase, the differential amplifier 130 differentially amplifies the electric signals from the DUT 99 and the standard sample 98. Background noise can be removed. As described above, the component concentration measuring apparatus 100 can reduce the instability due to the environmental temperature and the influence of background noise, reduce measurement errors, and increase measurement accuracy.

  FIG. 2 shows a schematic diagram of the first embodiment of the component concentration measuring apparatus according to the present embodiment. The component concentration measuring apparatus 100 according to this embodiment preferably further includes a heat sink 160 that is in contact with at least the standard sample 98 and the sound wave detection means 120 and 121. Furthermore, it is more preferable that the DUT 99 be disposed so as to be in contact with the heat sink 160. As the heat sink 160, a material having low specific heat and high thermal conductivity, for example, a single metal such as gold, silver, copper, palladium, platinum, iron, aluminum, titanium, tin, zinc, nickel, tungsten, iridium or stainless steel, There are housings made of alloys such as brass, bronze, carbon steel and geralumin. In addition, the heat sink 160 is only partially formed of a material having a low specific heat and high thermal conductivity, and the other part is made of ceramics such as glass, quartz, and alumina, an organic polymer material such as epoxy, acrylic and urethane, Or you may form with natural structural materials, such as natural rubber and wood. In FIG. 2, the heat sink 160 may accommodate the standard sample 98, the sound wave detection means 120 and 121, and the collimator 150, and the object to be measured 99 may be inserted and removed. As described above, the component concentration measuring apparatus 100 can reduce the temperature change of the standard sample 98 and the plurality of sound wave detection means 120 and 121, and can further reduce the measurement error.

  Further, since the heat sink 160 shields background noise, in the component concentration measurement apparatus 100 according to the present embodiment, the standard sample 98 and the plurality of sound wave detection means 120 and 121 are preferably shielded from background noise. It is more preferable that the measured object 99 is also shielded from background noise. Thereby, the component concentration measuring apparatus 100 can prevent the sound wave detecting means 120 and 121 from being saturated by the electromagnetic wave generated outside. As described above, the component concentration measurement apparatus 100 can reduce the influence of background noise and can further reduce measurement errors.

  In the component concentration measuring apparatus 100 according to this embodiment, it is preferable that at least the standard sample 98 and the plurality of sound wave detection units 120 and 121 are insulated from each other by using the heat sink 160 as a heat insulating structure. More preferably, it is insulated. For example, by attaching a heat insulating material such as urethane or epoxy to the inner wall surface of the heat sink 160, the heat sink 160 can have a heat insulating structure.

  Hereinafter, advantages of insulating the component concentration measuring apparatus 100 as compared with the conventional blood component concentration measuring apparatus will be described. The photoacoustic wave depends on the light absorbance of water, and the intensity of the photoacoustic wave greatly changes due to the influence of temperature change in high-precision measurement with a signal-to-noise ratio (SN ratio) of 1000 or more. In the conventional blood component concentration measuring apparatus, since the temperature fluctuations of the subject 99 and the standard sample 98 are not synchronized, for example, when measuring the glucose concentration in blood, the temperature due to the temperature change of water that does not contain glucose at all The correlation is obtained in advance. Then, the temperatures of the subject 99 and the standard sample 98 are accurately measured, and a temperature that is unrelated to the amount of glucose is corrected based on the measured temperature and the above temperature correlation. Further, in the conventional blood component concentration measuring apparatus, in a state where the two modulated laser beams are balanced, the ultrasonic wave from the standard sample 98 includes background noise, and the ultrasonic wave from the subject 99 is glucose. Signal, background noise, and temperature error due to the temperature difference between the subject 99 and the standard sample 98. For this reason, of the ultrasonic waves from the standard sample 98, the temperature error due to the temperature difference between the subject 99 and the standard sample 98 is corrected. However, it is difficult to accurately determine the temperature correlation and the temperatures of the subject 99 and the standard sample 98, and the conventional blood component concentration measurement has not always been able to accurately perform this correction.

  On the other hand, in the component concentration measuring apparatus 100, the temperature fluctuations of the standard sample 98 and the subject 99 are substantially equal due to the heat sink 160, and the temperature error due to the temperature difference between the subject 99 and the standard sample 98 due to ultrasonic waves from the subject 99 There is an advantage not included. For this reason, the component concentration measuring apparatus 100 does not need to correct the temperature error due to the temperature difference between the subject 99 and the standard sample 98. Further, the component concentration measuring apparatus 100 can measure the subject 99 and the standard sample 98 almost simultaneously, and has an advantage that a temperature error due to a measurement time difference between the subject 99 and the standard sample 98 can be ignored. Furthermore, the component concentration measuring apparatus 100 has an advantage that the influence of a sudden external temperature change can be reduced by the heat sink 160. As described above, the component concentration measuring apparatus 100 can further reduce the measurement error depending on the temperature.

  FIG. 3 is a schematic diagram of a second embodiment of the component concentration measuring apparatus according to the present embodiment, where (a) is a front view and (b) is a rear view. As shown in FIG. 3A, the upper part of the standard sample 98 and the lower part of the measurement object 99 are in contact with each other. 4 is a cross-sectional view of FIG. 3A, where FIG. 4A is AA ′ of FIG. 3A, and FIG. 4B is BB ′ of FIG. 3A. . In the component concentration measuring apparatus 100 according to the present embodiment, when the modulated laser beam is irradiated to the pressing unit 170 that presses the measured object 99 and the standard sample 98, the modulated laser beam irradiated to the measured object 99 is shielded. It is preferable to further include a shutter 140. The pressing means 170 is bent so that the cross-sectional shape becomes a U-shape, and an opposing pressing surface is formed, and the object 99 can be pressed by the pressing surface. Moreover, the press means 170 can be made to function as a heat sink by making the material of the press means 170 into a single metal or an alloy. In the pressing unit 170, two collimators 150 are embedded on the front side, and sound wave detection units 120 and 121 are embedded on the back side. The pressing unit 170 presses the standard sample 98 so as to be sandwiched between the sound wave detecting unit 121 and the collimator 150. Accordingly, the component concentration measuring apparatus 100 can keep the acoustic impedance of the boundary surface between the standard sample 98 and the measurement object 99 constant by the pressing unit 170, and can further reduce the measurement error.

  The component concentration measuring apparatus according to the present invention can be used for daily health management and cosmetic check. Moreover, not only humans but also animals can be used for health management. Moreover, the component concentration measuring apparatus according to the present invention can be applied not only to humans and animals but also to the field of measuring component concentrations in liquids, for example, sugar content measurement of fruits.

It is the schematic of the component concentration measuring apparatus which concerns on this embodiment. It is the schematic of the 1st form of the component concentration measuring apparatus which concerns on this embodiment. It is the schematic of the 2nd form of the component concentration measuring apparatus which concerns on this embodiment, (a) is a front view, (b) is a rear view. 3A is a cross-sectional view of FIG. 3A, FIG. 3A is A-A ′ in FIG. 3A, and FIG. 3B is B-B ′ in FIG. It is a figure which shows the structural example of the conventional blood component density | concentration measuring apparatus by a photoacoustic method. It is a figure which shows the structural example of the component concentration measuring apparatus of a 2nd prior art example. It is a figure shown about the relationship between the wavelength of excitation light, and the absorbency of water. It is a figure which shows the time-measurement result of signal strength when two waves of ultrasonic waves are balanced at a constant temperature for a standard sample. It is a figure which shows the time-measurement result of the signal strength at the time of temperature change about a standard sample.

Explanation of symbols

80 Blood component concentration measurement device 81 Drive circuit 82 Acoustic wave detector 83 Pulse light source 84 Waveform observation device 85 Housing 86 Opening 90 Component concentration measurement device 91a, 91b Drive circuit 92a, 92b Excitation light source 93 Ultrasonic detector 94 180 ° Phase shifter 95 Transmitter 96 Multiplexer 97 Phase detection amplifier 98 Standard sample 99 Device under test 100 Component concentration measuring device 110 Light irradiation means 111 Drive circuit 112 Excitation light source 113 Optical branching device 120, 121 Sound wave detection means 130 Differential amplifier 140 Shutter 150 Collimator 160 Heat sink 170 Pressing means

Claims (6)

A standard sample used for calibration, and
A light irradiating means for irradiating the object to be measured and the standard sample with modulated laser light obtained by electrically modulating the intensity of the laser light with a modulation signal having a constant frequency;
A plurality of sound wave detection means for detecting ultrasonic waves from the object to be measured and the standard sample generated by the irradiated modulated laser light and outputting them as electric signals;
A differential amplifier for differentially amplifying the electrical signals from the plurality of sound wave detection means;
A component concentration measuring device.   2. The component concentration measuring apparatus according to claim 1, wherein the standard sample is arranged at a position where the object to be measured can come into contact with. Pressing means for pressing the object to be measured;
A shutter that shields the modulated laser light applied to the object to be measured when the standard laser is irradiated with the modulated laser light;
The component concentration measuring apparatus according to claim 1, further comprising:   The component concentration measuring apparatus according to claim 1, further comprising a heat sink in contact with at least the standard sample and the plurality of sound wave detecting means.   5. The component concentration measuring apparatus according to claim 1, wherein at least the standard sample and the plurality of sound wave detection means are shielded from background noise.   6. The component concentration measuring apparatus according to claim 1, wherein at least the standard sample and the plurality of sound wave detecting means are insulated.

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