JP2017202138A - measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring device that can accurately measure concentration of a specific component contained in a liquid to be tested.SOLUTION: A lactic acid value measuring device 1 includes: a first detector 25 including stimulation response gel 24 that expands or contracts depending on stimulation of lactic acid of sweat 28 and provided between first electrodes 22; a second detector 26 for installing the sweat 28 between second electrodes 23; and an impedance measurement part 32 for measuring an electrical conductivity between the first electrodes 22 and an electrical conductivity between the second electrodes 23.SELECTED DRAWING: Figure 10

Description

  The present invention relates to a measuring apparatus.

  Living muscles contain pyruvic acid. Pyruvate is converted to lactic acid when the muscles are anaerobic. When blood lactate concentration increases due to anaerobic exercise, the lactate level in sweat also increases. In other words, it is thought that by detecting the lactate level in sweat, it is possible to obtain information on the exercise state of muscles (the degree of aerobic exercise and anaerobic exercise), and the relationship between sweat lactate and exercise state is studied. Has been.

  Patent Document 1 discloses a detection device that detects a substance located on the skin surface. According to this, the detection device comprises a stimulus-responsive gel that reacts with a specific substance. And since a stimulus-responsive gel reacts with salinity, it can detect salinity concentration. On the other hand, it is also possible to create a stimulus-responsive gel that reacts with lactic acid by changing the components of the stimulus-responsive gel.

JP, 2015-151436, A

  In Patent Document 1, the response of the stimulus-responsive gel was evaluated by a change in color. Since it is necessary to perform spectral analysis to evaluate the color change, it is difficult to make the device small and portable. Besides the color, the response of the stimulus-responsive gel can be evaluated by the change in conductivity. At this time, the conductivity can be realized by a small electric circuit and can be mounted on a portable device. The conductivity of the stimulus-responsive gel has a change in the gel itself, but there is also an influence of a change in the conductivity of the test liquid. Therefore, a measuring apparatus that can measure the concentration of a predetermined component contained in the liquid to be inspected with high accuracy without being affected by the conductivity of the liquid to be inspected has been desired.

  The present invention has been made to solve the above-described problems, and can be realized as the following forms or application examples.

[Application Example 1]
In the measurement apparatus according to this application example, a first detection unit in which a stimulus-responsive gel that expands or contracts due to stimulation by a predetermined component of a test liquid is disposed between first electrodes, and the test liquid is a second A second detection unit installed between the electrodes, and a measurement unit for measuring the conductivity between the first electrodes and the conductivity between the second electrodes are provided.

  According to this application example, the measurement apparatus includes the first detection unit, the second detection unit, and the measurement unit. In the first detector, a stimulus-responsive gel is installed between the first electrodes. This stimulus-responsive gel reacts with a predetermined component of the test liquid. In the second detection unit, the liquid to be inspected is placed between the second electrodes. And a measurement part measures the electrical conductivity between 1st electrodes. Furthermore, the measurement unit measures the conductivity between the second electrodes.

  The liquid to be inspected contains components other than the predetermined components in addition to the predetermined components. The stimulus-responsive gel reacts with a predetermined component of the test liquid. The measurement unit measures the electrical conductivity between the first electrodes. And a measurement part measures the electrical conductivity when the stimulus-responsive gel which reacts strongly with the density | concentration of a predetermined component contains the to-be-tested liquid. On the other hand, there is a liquid to be inspected between the second electrodes and there is no stimulus-responsive gel. And a measurement part measures the electrical conductivity corresponding to a to-be-tested liquid by measuring the electrical conductivity between 2nd electrodes.

  Therefore, by using the conductivity between the first electrodes and the conductivity between the second electrodes, the measuring apparatus can reduce the influence of the conductivity of components other than the predetermined component from the conductivity between the first electrodes. it can. As a result, the concentration of the predetermined component contained in the liquid to be inspected can be accurately measured.

[Application Example 2]
In the measurement apparatus according to the application example, the measurement unit includes a power supply unit that supplies an AC voltage between the first electrodes and between the second electrodes, a current that flows between the first electrodes, and the second electrode. And an ammeter for detecting a flowing current.

  According to this application example, the measuring apparatus includes a power supply unit and an ammeter. The power supply unit supplies an alternating voltage between the first electrodes and between the second electrodes. The ammeter detects a current flowing between the first electrodes and a current flowing between the second electrodes. Therefore, the measurement unit can measure the conductivity between the first electrodes and the conductivity between the second electrodes.

  An electric double layer is formed by water molecules on the surface of each electrode. And when a power supply part applies a DC voltage between each electrode, since an electric double layer acts as an electric capacity, electrical conductivity cannot be measured accurately. In this application example, the power supply unit supplies an AC voltage. Accordingly, since an alternating current flows between the electrodes, the influence of the electric double layer in the measurement of conductivity can be reduced.

[Application Example 3]
In the measurement apparatus according to the application example, a storage unit that stores a correlation table indicating a relationship between the conductivity between the first electrodes and the conductivity between the second electrodes and the amount of the predetermined component, and the measurement unit And a calculation unit that calculates the concentration of lactic acid contained in the test liquid using the conductivity between the first electrodes measured by the first electrode, the conductivity between the second electrodes, and the correlation table. And

  According to this application example, the measurement apparatus includes a calculation unit and a storage unit. The storage unit stores a correlation table, and the correlation table indicates the relationship between the conductivity between the first electrodes, the conductivity between the second electrodes, and the concentration of a predetermined component. Then, the calculation unit calculates the concentration of lactic acid contained in the test liquid. At this time, the calculation unit uses the conductivity between the first electrodes measured by the measurement unit, the conductivity between the second electrodes, and the correlation table.

  Even when the relationship between the conductivity between the first electrodes and the conductivity between the second electrodes and the concentration of the predetermined component is nonlinear, the correlation between the conductivity between the first electrodes and the conductivity between the second electrodes is shown in the correlation table. The relationship with the concentration of the predetermined component can be shown. Therefore, the calculation unit can reliably calculate the concentration of lactic acid contained in the test solution with high accuracy.

[Application Example 4]
In the measuring apparatus according to the application example described above, the frequency of the AC voltage is 10 kHz to 1 MHz.

  According to this application example, the frequency of the AC voltage is 10 KHz to 1 MHz. When the frequency of the AC voltage is less than 10 KHz, it is affected by the electric capacitance component of the electric double layer formed at the interface between the electrode and the liquid to be inspected, so that the accuracy of the measured conductivity decreases. When the frequency of the AC voltage exceeds 1 MHz, it is affected by the capacitance component of the stimulus-responsive gel and the electrical induction component of the measurement system, so that the accuracy of the measured conductivity is lowered. When the frequency of the AC voltage is 10 KHz or more and 1 MHz or less, it is difficult to be influenced by the electric capacitance component of the electric double layer and the electric capacitance component of the stimulus-responsive gel, so that the conductivity can be measured with high accuracy.

[Application Example 5]
In the measurement apparatus according to the application example, the stimulus-responsive gel is sandwiched between the first electrodes facing each other in the first detection unit, and the area of the stimulus-responsive gel is in a contracted state. Is wider than the first electrode.

  According to this application example, the stimulus-responsive gel is sandwiched between the opposing first electrodes in the first detection unit. Even when the stimulus-responsive gel contracts, the area of the stimulus-responsive gel is wider than that of the first electrode. Therefore, the area where the first electrode contacts the stimulus-responsive gel can be prevented from changing due to the contraction and expansion of the stimulus-responsive gel. Therefore, it can suppress that the measurement precision of the electrical conductivity between 1st electrodes falls by contraction and expansion | swelling of stimulus-responsive gel.

[Application Example 6]
In the measurement apparatus according to the application example, the first detection unit includes a substrate, the first electrode disposed in a comb shape on the substrate, and the stimulus-responsive gel disposed on the first electrode. And.

  According to this application example, the first electrode is disposed on the substrate, and the first electrode has a comb shape. A stimulus-responsive gel is placed on the first electrode. Therefore, since the stimulus-responsive gel is located between the comb-shaped first electrodes, the measurement unit can measure the conductivity between the first electrodes. And since the 1st detection part is the structure which piles up and installs a 1st electrode and stimulus responsive gel on a board | substrate, it can manufacture a measuring apparatus with sufficient productivity.

[Application Example 7]
In the measurement apparatus according to the application example, the stimulus-responsive gel is thicker than the first electrode.

  According to this application example, the stimulus-responsive gel is thicker than the first electrode. Therefore, since the first electrode is not exposed from the stimulus-responsive gel, the conductivity between the first electrodes can be stably measured.

[Application Example 8]
In the measurement apparatus according to the application example, the first detection unit is detachably attached to the measurement unit.

  According to this application example, the first detection unit is installed to be detachable from the measurement unit. Therefore, by changing the stimulus-responsive gel, the stimulus-responsive gel can be easily transferred to a state that does not include a predetermined component.

The schematic diagram for demonstrating the example of installation of the lactic-acid-value measuring apparatus in connection with 1st Embodiment. The schematic plan view which shows the structure of a lactic acid value measuring apparatus. The schematic plan view which shows the structure of a lactic acid value measuring apparatus. The disassembled perspective view which shows the structure of a lactic acid value measuring apparatus. The schematic plan view for demonstrating the structure of a sensor module. The schematic side view for demonstrating the structure of a sensor module. The schematic diagram for demonstrating the function of a sensor module. The schematic side view for demonstrating the opening / closing structure of a back cover. The electric control block diagram of a lactic acid value measuring apparatus. The figure for demonstrating the structure of an impedance measurement part. The schematic diagram for demonstrating the electric field in a 1st electrode. The schematic diagram for demonstrating the electric field in a 2nd electrode. The figure which shows the frequency characteristic of the impedance of a stimulus responsive gel. The figure which shows the frequency characteristic of the phase difference of the electric current with respect to the voltage of a stimulus responsive gel. The figure which shows the frequency characteristic of the impedance of a stimulus responsive gel and sweat. The figure which shows the relationship between electrical conductivity ratio and the weight change rate of a stimulus responsive gel. The figure which shows the relationship between the calculated value of electrical conductivity, and the weight change rate of a stimulus responsive gel. The figure which shows the relationship between the sodium lactate concentration and the weight change rate of a stimulus responsive gel. The figure which shows the relationship between a sodium lactate density | concentration and a calculated value. The figure for demonstrating the table format of a correlation table. The schematic perspective view which shows the structure of the sensor module in connection with 2nd Embodiment. The schematic side view which shows the structure of a sensor module. The schematic plan view which shows the structure of a sensor module. The schematic side view which shows the structure of the sensor module in connection with 3rd Embodiment. The schematic plan view which shows the structure of a sensor module.

  Hereinafter, embodiments will be described with reference to the drawings. In addition, each member in each drawing is illustrated with a different scale for each member in order to make the size recognizable on each drawing.

(First embodiment)
In this embodiment, a characteristic example of a lactic acid value measuring apparatus and a lactic acid value measuring method for measuring a lactic acid value using a lactic acid value measuring apparatus will be described with reference to the drawings. The lactic acid value measuring apparatus according to the first embodiment will be described with reference to FIGS. FIG. 1 is a schematic diagram for explaining an installation example of a lactic acid value measuring apparatus. As shown in FIG. 1, a lactic acid value measuring apparatus 1 as a measuring apparatus is installed on the wrist of a subject 2 as a subject. The lactic acid value measuring device 1 is a medical measuring device that measures the lactic acid value of lactic acid as a predetermined component contained in the sweat of the subject 2, and is used as health monitoring or medical equipment. The lactic acid value measuring apparatus 1 measures the sweat that comes out of the wrist.

  2 and 3 are schematic plan views showing the structure of the lactic acid value measuring apparatus. 2 shows the surface of the lactic acid value measuring apparatus 1, and FIG. As shown in FIG. 2, the lactic acid value measuring apparatus 1 has a shape similar to that of a wristwatch. The lactic acid value measuring apparatus 1 includes an exterior part 3. Fixed bands 4 are installed on the left and right sides of the exterior part 3 in the figure, and the fixed bands 4 fix the lactate measuring device 1 to a measured part such as a wrist or an arm of the subject 2. A magic tape (registered trademark) is used for the fixed band 4. In the lactic acid value measuring apparatus 1, the direction in which the fixed band 4 extends is defined as the Y direction, and the direction in which the arm of the subject 2 extends is defined as the X direction. The direction in which the lactic acid value measuring apparatus 1 faces the subject 2 is defined as the Z direction. The X direction, the Y direction, and the Z direction are orthogonal to each other.

  The surface 3 a of the exterior portion 3 is a surface that faces outward when the patient 3 is attached to the subject 2. An operation switch 5 and a display unit 6 are installed on the surface 3 a of the exterior unit 3. The subject 2 inputs a measurement start instruction using the operation switch 5. Then, measurement result data is displayed on the display unit 6.

  As shown in FIG. 3, a sensor module 7 as a gel sensor is installed on the back surface 3 b side of the exterior part 3. The sensor module 7 is used facing the skin of the subject 2. The sensor module 7 is a device that detects lactic acid contained in sweat secreted into the skin of the subject 2. In the lactic acid value measuring apparatus 1, the skin is the surface to be inspected and the sweat is the liquid to be inspected. The sensor module 7 is a sensor incorporating a stimulus-responsive gel that expands or contracts by stimulation with lactic acid contained in sweat. In other words, the sensor module 7 is a sensor incorporating a stimulus-responsive gel that expands or contracts by reacting with lactic acid contained in sweat. The predetermined component of the liquid to be inspected corresponds to lactic acid. A communication connector 8 for communicating with an external device is installed on the back surface 3 b of the exterior part 3. The communication connector 8 has contacts arranged so as to communicate with a cord connected to an external device. In addition, a power connector 9 for filling a rechargeable storage battery (not shown) is provided. The power connector 9 is a connector for inputting power.

  FIG. 4 is an exploded perspective view showing the structure of the lactic acid value measuring apparatus. As shown in FIG. 4, the lactic acid value measuring apparatus 1 is configured by stacking a back cover 10, a sensor module 7, a circuit unit 11, a spacer 12, a display unit 6, and a front case 13 in this order from the + Z direction side. The outer cover 3 is configured by the back cover 10 and the front case 13. The sensor module 7, the circuit unit 11, the spacer 12, the display unit 6, and the like are housed in the exterior unit 3.

  The back cover 10 is a plate-like member, and is a member that faces and contacts the skin of the subject 2. The back cover 10 is provided with a rectangular first window portion 10a on the + X direction side, and a part of the sensor module 7 is exposed from the first window portion 10a. The back cover 10 is provided with a rectangular second window portion 10b and a third window portion 10c on the −X direction side. The second window portion 10b is a place where the communication connector 8 is exposed, and the third window portion 10c is a place where the power connector 9 is exposed. A hinge 10d is installed on the back cover 10 on the + X direction side. One of the hinges 10d is connected to the front case 13. In the case back 10, a recess 10 e is provided on the side surface on the −X direction side. The recess 10e is used when the back cover 10 is kept closed.

  The sensor module 7 includes a substrate 14 on which a first terminal 15 and a second terminal 16 are installed. Each of the first terminal 15 and the second terminal 16 has a pair of terminals. The circuit unit 11 includes a circuit board 17. An electric circuit 18 for driving and controlling the sensor module 7 and the display unit 6 is installed on the circuit board 17. The electric circuit 18 is composed of a plurality of semiconductor chips. In addition, an operation switch 5, a communication connector 8, a power connector 9, and a rechargeable storage battery 21 are installed on the circuit board 17. The rechargeable storage battery 21 is electrically connected to the power connector 9 and can be charged via the power connector 9.

  The spacer 12 is a structure that is installed between the circuit unit 11 and the display unit 6. The surface of the circuit unit 11 on the −Z direction side is uneven, because a plurality of electric elements are installed. The spacer 12 is placed over the circuit board 17 to flatten the surface on the display unit 6 side. The spacer 12 is provided with a plurality of holes 12a, and the operation switch 5 passes through the holes 12a.

  The display unit 6 is a device that displays the lactic acid value detected by the sensor module 7 and the measurement status. The display unit 6 is not particularly limited as long as the electronic data can be displayed as an image, and a liquid crystal display device, an OLED (Organic light-emitting diodes) display device, or the like can be used. In the present embodiment, for example, an OLED display device is used for the display unit 6.

  The operation switch 5 is a switch for operating the lactic acid value measuring apparatus 1. The operator operates the operation switch 5 to input various instructions such as a measurement start instruction and measurement conditions for the lactic acid value. A plurality of holes 13a are provided in the front case 13, and the operation switch 5 and the display unit 6 are exposed from the holes 13a. Then, the back cover 10 and the front case 13 are accommodated with the respective parts of the display unit 6 sandwiched from the sensor module 7.

  FIG. 5 is a schematic plan view for explaining the structure of the sensor module. FIG. 6 is a schematic side view for explaining the structure of the sensor module. As shown in FIGS. 5 and 6, the sensor module 7 includes a substrate 14, and the first electrode 22 and the second electrode 23 are installed on the substrate 14. The first electrode 22 includes a first positive electrode 22a and a first sub electrode 22b, and a certain distance is provided between the first positive electrode 22a and the first sub electrode 22b. The first positive electrode 22a and the first sub electrode 22b are uneven on the opposite sides. And since a convex part enters into a recessed part, the distance of the 1st positive electrode 22a and the 1st subelectrode 22b is extended long with the equal distance. The first electrode 22 is disposed in a comb shape on the substrate 14.

  The stimulus-responsive gel 24 is placed between and above the convex portions of the first positive electrode 22a and the first sub-electrode 22b. The stimulus-responsive gel 24 is a gel containing a drug that reacts with sweat. The stimulus-responsive gel 24 expands or contracts by stimulation with lactic acid contained in sweat. A first detection unit 25 is configured by the substrate 14, the first electrode 22, the stimulus-responsive gel 24, and the like.

  The stimulus-responsive gel 24 is thicker than the first electrode 22. Accordingly, since the first electrode 22 is not exposed from the stimulus-responsive gel 24 at the place where the stimulus-responsive gel 24 is installed, the first detector 25 can stably measure the conductivity between the first electrodes 22. it can.

  The constituent material of the stimulus-responsive gel 24 is not particularly limited. In the present embodiment, the constituent material is, for example, a material including a polymer material having a crosslinked structure and a solvent. The polymer material has become a drug that reacts to sweat. As the polymer material constituting the stimulus-responsive gel 24, for example, a material obtained by reacting a monomer, a polymerization initiator, a crosslinking agent, or the like can be used. A monomer is also referred to as a monomer.

  Examples of the monomer constituting the stimulus-responsive gel 24 include acrylamide, N-methylacrylamide, N-isopropylacrylamide, N, N-dimethylacrylamide, N, N-dimethylaminopropylacrylamide, N, N- Various quaternary salts of dimethylaminopropylacrylamide, acryloylmorpholine, various quaternary salts of N, N-dimethylaminoethyl acrylate, acrylic acid, various alkyl acrylates, methacrylic acid, various alkyl methacrylates, 2-hydroxyethyl methacrylate, glycerol monomethacrylate, N -Vinylpyrrolidone, acrylonitrile, styrene, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropy Glycol diacrylate, polypropylene glycol diacrylate, 2,2-bis [4- (acryloxydiethoxy) phenyl] propane, 2,2-bis [4- (acryloxypolyethoxy) phenyl] propane, 2-hydroxy- 1-acryloxy-3-methacryloxypropane, 2,2-bis [4- (acryloxypolypropoxy) phenyl] propane, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1, 3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2-hydroxy 1,3-dimethacryloxypropane, 2,2-bis [4- (methacryloxyethoxy) phenyl] propane, 2,2-bis [4- (methacryloxyethoxydiethoxy) phenyl] propane, 2,2-bis [4- (methacryloxyethoxypolyethoxy) phenyl] propane, trimethylolpropane trimethacrylate, tetramethylolmethane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethane triacrylate, tetramethylolmethane tetraacrylate, dipentaerythritol hexaacrylate, N, N′-methylenebisacrylamide, N, N′-methylenebismethacrylamide, diethylene glycol diallyl ether, divinylbenzene and the like can be mentioned.

  As a monomer for detecting lactic acid, 3-acrylamidophenylboronic acid, vinylphenylboronic acid, acryloyloxyphenylboronic acid, N-isopropylacrylamide (NIPAAm), ethylenebisacrylamide, N-hydroxyethylacrylamide, etc. are suitable. Can be used. Specifically, as the monomer, one or more monomers selected from the group consisting of 3-acrylamidophenylboronic acid, vinylphenylboronic acid and acryloyloxyphenylboronic acid, and N-isopropylacrylamide ( NIPAAm), ethylenebisacrylamide and N-hydroxyethylacrylamide are preferably used in combination with one or more monomers selected from the group consisting of NIPAAm), ethylenebisacrylamide and N-hydroxyethylacrylamide.

  As a polymerization initiator, it can select suitably by the polymerization mode, for example. Specifically, hydrogen peroxide, persulfate such as potassium persulfate, sodium persulfate, ammonium persulfate and the like, and azo initiator such as 2,2′-azobis (2-amidinopropane) 2 hydrochloric acid are used as polymerization initiators. Salt, 2,2'-azobis (N, N'-dimethyleneisobutylamidine) dihydrochloride, 2,2'-azobis {2-methyl-N- [1,1, -bis (hydroxymethyl) -2- Hydroxyethyl] propionamide}, 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 4,4′-azobis (4-cyanovaleric acid), 2,2′- Azobisisobutyronitrile, 2,2′-azobis (2,4′-dimethylvaleronitrile), benzophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclo Xylphenylketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphonoxide, 1- [4- (2-hydroxyethoxy) -phenyl] -2- Compounds that generate radicals by ultraviolet light, such as hydroxy-2-methyl-1-propan-1-one, 2,4-diethylthioxanthone, isopropylthioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino -2-hydroxypropoxy) -3,4-dimethyl-9H-thioxanthone-9-one mesochloride, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropane-1, 2-benzyl-2- Dimethylamino-1- (4-morpholinophenyl) -butanone-1, bi (Cyclopentadienyl) -bis (2,6-difluoro-3- (pyr-1-yl) titanium, 1,3-di (t-butylperoxycarbonyl) benzene and 3,3 ′, 4,4′- Use a compound that generates a radical by light having a wavelength of 360 nm or more, such as a substance in which a peroxyester such as tetra- (t-butylperoxycarbonyl) benzophenone is mixed with a thiopyrylium salt, a merocyanine, a quinoline, or a stilquinoline dye. Hydrogen peroxide or persulfate can also be used as a redox initiator by combining a reducing substance such as sulfite and L-ascorbic acid and an amine salt.

  As the crosslinking agent, a compound having two or more polymerizable functional groups can be used. Specifically, ethylene glycol, propylene glycol, trimethylolpropane, glycerin, polyoxyethylene glycol, polyoxypropylene glycol, polyglycerin. N, N'-methylenebisacrylamide, N, N-methylene-bis-N-vinylacetamide, N, N-butylene-bis-N-vinylacetamide, tolylene diisocyanate, hexamethylene diisocyanate, allylated starch, allylated Use of cellulose, diallyl phthalate, tetraallyloxyethane, pentaerythritol triallyl ether, trimethylolpropane triallyl ether, diethylene glycol diallyl ether, triallyl trimellitate, etc. Kill.

  The stimulus-responsive gel may include a plurality of different polymer materials. The content of the polymer material in the stimulus-responsive gel is preferably 0.7% by mass or more and 36.0% by mass or less, and more preferably 2.4% by mass or more and 27.0% by mass or less. .

  By making the stimulus-responsive gel 24 contain a solvent, the polymer material can be suitably gelled. As the solvent, various organic solvents and inorganic solvents can be used. More specifically, the solvent is, for example, water; various alcohols such as methanol and ethanol; ketones such as acetone; ethers such as tetrahydrofuran and diethyl ether; amides such as dimethylformamide; n-pentane, n-hexane, Examples include chain aliphatic hydrocarbons such as n-heptane and n-octane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; aromatics such as benzene, toluene and xylene, and the like, particularly those containing water. Is preferred.

  The stimulus-responsive gel 24 may include a plurality of different components as solvents. The content of the solvent in the stimulus-responsive gel 24 is preferably 30% by mass or more and 95% by mass or less, and more preferably 50% by mass or more and 90% by mass or less.

  Although the magnitude | size of the stimulus responsive gel 24 is not specifically limited, In this embodiment, the length of the long side of the stimulus responsive gel 24 is 20 mm, for example. When the stimulus-responsive gel 24 is manufactured, a monomer, a polymerization initiator, a cross-linking agent, or the like is applied to the substrate 14 to be reacted. By controlling the film thickness of the material to be applied with high accuracy, the thickness of the stimulus-responsive gel 24 can be formed with high accuracy.

  The stimulus-responsive gel 24 has a polymer chain. Many boronic acid groups are installed in this polymer chain. When lactic acid has not penetrated into the stimulus-responsive gel 24, the boronic acid groups are bonded to each other and the polymer chains are in close proximity. Thereby, the stimulus-responsive gel 24 is in a contracted state. When lactic acid penetrates into the stimulus-responsive gel 24, the boronic acid group and lactic acid are bonded. When the stimulus-responsive gel 24 reacts with lactic acid, the polymer chain is dissociated, and the volume of the stimulus-responsive gel 24 expands. Since the form of the stimulus responsive gel 24 changes, the conductivity of the stimulus responsive gel 24 changes. Therefore, the concentration of lactic acid permeated into the stimulus-responsive gel 24 can be detected by measuring the electrical conductivity between the first electrodes 22.

  A second electrode 23 is disposed on the substrate 14 on the −Y direction side of the first detection unit 25. The second electrode 23 includes a second positive electrode 23 a and a second sub electrode 23 b, and the second electrode 23 has the same shape as the first electrode 22. There is a certain distance between the second positive electrode 23a and the second sub electrode 23b. The second positive electrode 23a and the second sub electrode 23b are uneven on the opposite sides. And since a convex part enters into a recessed part, the distance of the 2nd positive electrode 23a and the 2nd subelectrode 23b is extended long with the equal distance. The second electrode 23 is disposed on the substrate 14 in a comb shape. A second detection unit 26 is configured by the substrate 14, the second electrode 23, and the like.

  Eight struts 27 are installed between the first detection unit 25 and the second detection unit 26. The struts 27 function as spacers that are spaced so that the skin of the subject 2 does not come into contact with the first detection unit 25 and the second detection unit 26.

  In the board | substrate 14, the surface in which the 1st detection part 25 and the 2nd detection part 26 were installed is made into the surface 14a, and the surface on the opposite side to the surface 14a is made into the back surface 14b. A first terminal 15 including a first positive terminal 15a and a first sub terminal 15b is installed on the back surface 14b. The substrate 14 is provided with a plurality of through electrodes 14c from the front surface 14a to the back surface 14b. The first positive electrode 22a and the first positive terminal 15a are connected by the through electrode 14c. The first sub electrode 22b and the first sub terminal 15b are connected by the through electrode 14c.

  Similarly, a second terminal 16 including a second positive terminal 16a and a second subterminal 16b is provided on the back surface 14b. The second positive electrode 23a and the second positive terminal 16a are connected by the through electrode 14c. The second sub electrode 23b and the second sub terminal 16b are connected by the through electrode 14c. The first terminal 15 and the second terminal 16 are connected to the electric circuit 18 of the circuit unit 11 by wiring (not shown).

  FIG. 7 is a schematic diagram for explaining the function of the sensor module. As shown in FIG. 7, when the lactic acid value measuring apparatus 1 is installed on the subject 2, the surface on the subject 2 side when the back cover 10 comes into contact with the subject 2 is defined as a surface 2 a to be examined. The surface 2a to be inspected is the surface of the skin on which the sweat glands are installed. Since the support column 27 is installed between the substrate 14 and the surface to be inspected 2 a, the surface to be inspected 2 a does not contact the first detector 25 and the second detector 26.

  Sweat 28 as a liquid to be inspected is supplied from the surface 2a to be inspected. Then, sweat 28 is filled between the substrate 14 and the surface 2a to be inspected. When the sweat 28 reaches the stimulus responsive gel 24, the stimulus responsive gel 24 absorbs the sweat 28 and reacts with lactic acid contained in the sweat 28 to swell. In the second detector 26, sweat 28 is installed between the second electrodes 23. As a result, in the second detection unit 26, a current flows through the sweat 28 between the second electrodes 23.

  FIG. 8 is a schematic side view for explaining the back cover opening and closing structure. As shown in FIG. 8, the back cover 10 opens and closes around a hinge 10d. When the back cover 10 is opened, all the sensor modules 7 are exposed. Then, the operator can attach and detach the sensor module 7. On the −X direction side of the front case 13, an open / close knob 29 is installed so as to be movable in the X direction. The opening / closing knob 29 is biased in the + X direction by a spring (not shown). On the + X direction side of the opening / closing knob 29, a convex portion 29a where two surfaces intersect is provided.

  The back cover 10 is closed with the hinge 10d as an axis. At this time, the convex portion 29 a of the opening / closing knob 29 is inserted into the concave portion 10 e of the back cover 10. Thereby, the opening / closing knob 29 can maintain the state where the back cover 10 is closed. As described above, the sensor module 7 on which the first detection unit 25 is installed is detachably installed on the circuit unit 11. Therefore, by changing the stimulus-responsive gel 24, the stimulus-responsive gel 24 can easily shift to a state that does not contain lactic acid.

  FIG. 9 is an electric control block diagram of the lactic acid value measuring apparatus. As shown in FIG. 9, the lactic acid value measuring apparatus 1 includes an electric circuit 18 as a control unit that controls the operation of the lactic acid value measuring apparatus 1. The electric circuit 18 includes a CPU 30 (Central Processing Unit) that performs various arithmetic processes as a processor, and a memory 31 as a storage unit that stores various information. An impedance measurement unit 32 as a measurement unit, an A / D conversion unit 33 (Analog Digital) as a measurement unit, a display unit 6, an operation switch 5, and a communication unit 34 are connected to the CPU 30 via an input / output interface 35 and a data bus 36. Has been.

  The impedance measurement unit 32 detects an electric current flowing between the first electrodes 22 by applying an AC voltage to the pair of first electrodes 22 installed on the stimulus-responsive gel 24 of the first detection unit 25. The impedance of the stimulus-responsive gel 24 changes according to the lactic acid value of lactic acid contained in the stimulus-responsive gel 24. The impedance measuring unit 32 detects the current flowing through the stimulus-responsive gel 24 and detects the impedance of the stimulus-responsive gel 24 corresponding to the lactic acid value.

  Further, the impedance measurement unit 32 applies an AC voltage to the pair of second electrodes 23 installed in the second detection unit 26 to detect a current flowing between the second electrodes 23. The impedance of the sweat 28 changes according to the components contained in the sweat 28. The impedance measuring unit 32 detects the current flowing through the sweat 28 and detects the impedance of the sweat 28. That is, the impedance measuring unit 32 measures the impedance between the first electrodes 22 and the impedance between the second electrodes 23.

  The A / D converter 33 is a part that converts the impedance of the stimulus-responsive gel 24 and the impedance of the sweat 28 detected by the impedance measuring unit 32 from an analog signal into a digital data signal and outputs the converted data signal. The A / D converter 33 is connected to the impedance measuring unit 32 and receives an impedance signal from the impedance measuring unit 32. Then, the A / D converter 33 outputs a data signal to the input / output interface 35.

  The communication unit 34 is a part that communicates with an external device. The communication unit 34 transmits the measured lactic acid value data to the external device. Furthermore, measurement conditions are input from an external device. When communicating with an external device via a cable, the communication connector 8 is installed with a cable for communication. An antenna may be installed for wireless communication, or a light emitting device and a light receiving device may be installed for optical communication.

  The memory 31 is a concept including a semiconductor memory such as a RAM and a ROM, and an external storage device such as a hard disk and a DVD-ROM. Functionally, there is a storage area for storing program software 37 in which a procedure for controlling the operation of the lactic acid value measuring apparatus 1 is described, and a storage area for storing coefficient data used when calculating conductivity from impedance. Is set. In addition, a storage area for storing data of the correlation table 38 indicating the relationship between the conductivity and the lactic acid value is set. The correlation table 38 shows the relationship between the conductivity between the first electrodes 22 and the conductivity between the second electrodes 23 and the amount of lactic acid contained in the sweat 28. In addition, a storage area that functions as a work area, a temporary file, and the like for the CPU 30 and various other storage areas are set.

  The CPU 30 performs control for measuring the lactic acid value according to the program software stored in the memory 31. As a specific function implementation unit, the CPU 30 includes a conductivity calculation unit 40 as a measurement unit and a lactic acid value calculation unit 41 as a calculation unit. The conductivity calculator 40 receives an impedance data signal from the A / D converter 33. The conductivity calculator 40 calculates the conductivity using the impedance data and a predetermined coefficient. This predetermined coefficient is determined by the shapes of the first electrode 22, the second electrode 23, and the stimulus-responsive gel 24. Then, the lactic acid value calculation unit 41 calculates the lactic acid value with reference to the conductivity and correlation table 38. That is, the lactic acid value calculation unit 41 is included in the sweat 28 using the conductivity between the first electrodes 22 and the conductivity between the second electrodes 23 measured by the impedance measurement unit 32 and the conductivity calculation unit 40 and the correlation table 38. Calculate the concentration of lactic acid.

  In addition, the CPU 30 controls the voltage value that the impedance measuring unit 32 outputs to the first electrode 22 and the second electrode 23. In addition, the CPU 30 performs control to output the lactic acid value calculated by the lactic acid value calculating unit 41 to the display unit 6. Further, the CPU 30 controls the operation of the lactic acid value measuring apparatus 1 according to the signal input from the operation switch 5. Further, the CPU 30 drives the communication unit 34 to output a lactic acid value data signal to the external device, and inputs measurement conditions from the external device.

  FIG. 10 is a diagram for explaining the configuration of the impedance measuring unit. As shown in FIG. 10, the impedance measurement unit 32 includes a power supply unit 42, an ammeter 43, and a switch 44. The power supply unit 42 is an AC power supply having two terminals of a first terminal 42a and a second terminal 42b, and the frequency of the AC voltage is 10 KHz or more and 1 MHz or less. The power supply unit 42 is connected to the CPU 30, and the voltage and frequency are controlled by the CPU 30. The ammeter 43 also has two terminals, a first terminal 43 a and a second terminal 43 b, and the first terminal 42 a of the power supply unit 42 is connected to the first terminal 43 a of the ammeter 43. The second terminal 42b of the power supply unit 42 is connected to the first positive electrode 22a and the second positive electrode 23a.

  The switch 44 has three terminals, a first terminal 44a, a second terminal 44b, and a third terminal 44c. The switch 44 can short-circuit the first terminal 44a and the second terminal 44b, or can short-circuit the first terminal 44a and the third terminal 44c. The second terminal 44b is connected to the first sub electrode 22b, and the third terminal 44c is connected to the second sub electrode 23b.

  When the switch 44 short-circuits the first terminal 44 a and the second terminal 44 b, the power supply unit 42 supplies an AC voltage between the first electrodes 22. The ammeter 43 detects the current flowing between the first electrodes 22. When the switch 44 short-circuits the first terminal 44 a and the third terminal 44 c, the power supply unit 42 supplies an AC voltage between the second electrodes 23. The ammeter 43 detects the current flowing between the second electrodes 23. The switch 44 is connected to the CPU 30 and performs switching based on an instruction signal from the CPU 30.

  The impedance measurement unit 32 is provided with a division circuit 45 and an output terminal 46, and a voltage signal indicating the voltage of the power supply unit 42 is output to the division circuit 45. Further, a current signal indicating the current detected by the ammeter 43 is also output to the division circuit 45. The division circuit 45 calculates the impedance by dividing the voltage signal by the current signal. Then, an impedance signal indicating impedance is output to the output terminal 46. As described above, the impedance measuring unit 32 measures and outputs the impedance between the first electrodes 22 and the impedance between the second electrodes 23.

  When the power supply part 42 applies a voltage between each electrode, the electric double layer by a water molecule is formed in each electrode surface. And when the power supply part 42 applies a DC voltage between each electrode, since an electric double layer acts as an electric capacity, electrical conductivity cannot be measured accurately. In the present embodiment, the power supply unit 42 supplies an alternating voltage. Accordingly, since an alternating current flows between the electrodes, the influence of the electric double layer in the impedance measurement can be reduced.

  In the impedance measurement unit 32, the power supply unit 42 and the ammeter 43 detect the impedance of the first detection unit 25 and the impedance of the second detection unit 26 by switching the circuit with the switch 44. Therefore, the configuration of the measurement system can be simplified. In order to measure the minute resistance value of the stimulus-responsive gel 24, it is preferable to reduce the resistance value of the wiring in the impedance measuring unit 32 as much as possible. Furthermore, it is preferable to reduce the resistance value between the impedance measuring unit 32 and the wiring between the first electrode 22 and the second electrode 23 as much as possible.

  FIG. 11 is a schematic diagram for explaining the electric field in the first electrode. As shown in FIG. 11, in the first detection unit 25, the first positive electrode 22 a and the first sub electrode 22 b are arranged side by side on the substrate 14. The first positive electrode 22 a and the first sub electrode 22 b are covered with a stimulus-responsive gel 24. When the switch 44 short-circuits the first terminal 44a and the second terminal 44b, a current 47 flows between the first positive electrode 22a and the first sub electrode 22b. Since the power supply unit 42 is an AC power supply, the direction in which the current 47 flows is switched at a predetermined frequency.

  Since the electric field generated between the first electrodes 22 is concentrated between the first electrodes 22 and does not occur in a place away from the first electrode 22, the stimulation-responsive gel 24 does not need to be thick. However, it is preferable that the thickness of the stimulus-responsive gel 24 is thicker than that of the first electrode 22 so as to cover the first electrode 22 between the electrodes. When the thickness of the stimulus-responsive gel 24 is smaller than the thickness of the first electrode 22, the current flowing between the first electrodes 22 includes the current that has passed through the stimulus-responsive gel 24 and the current that has passed through the sweat 28. Therefore, it becomes difficult to detect the impedance of the stimulus-responsive gel 24. In the present embodiment, for example, the thickness of the first electrode 22 is set to 50 nm to 100 nm, and the thickness of the stimulus-responsive gel 24 is set to 100 nm to 1 mm.

  FIG. 12 is a schematic diagram for explaining the electric field in the second electrode. As shown in FIG. 12, in the second detection unit 26, the second positive electrode 23 a and the second sub electrode 23 b are arranged side by side on the substrate 14, and the second positive electrode 23 a and the second sub electrode 23 b are covered with sweat 28. ing. When the switch 44 short-circuits the first terminal 44a and the third terminal 44c, a current 47 flows between the second positive electrode 23a and the second sub electrode 23b. Since the power supply unit 42 is an AC power supply, the direction in which the current 47 flows is switched at a predetermined frequency.

  The conductivity of the sweat 28 detected using the second electrode 23 is preferably the same as the conductivity of the sweat 28 included in the stimulus responsive gel 24. Therefore, it is preferable that the first detection unit 25 and the second detection unit 26 be installed in a close place.

  FIG. 13 is a diagram showing the frequency characteristics of the impedance of the stimulus-responsive gel. In FIG. 13, the vertical axis represents the impedance of the stimulus-responsive gel 24, and the horizontal axis represents the frequency of the AC voltage output from the power supply unit 42. The impedance on the vertical axis is higher on the upper side than on the lower side in the figure, and has a logarithmic scale. The frequency on the horizontal axis is higher on the right side of the diagram than on the left side, and is a logarithmic scale. A first characteristic line 48 indicates the impedance characteristic of the stimulus-responsive gel 24 with respect to the frequency of the AC voltage.

  When the frequency of the AC voltage is 1 KHz or less, the impedance of the electric double layer at the electrode interface of the first electrode 22 is dominant. The electric double layer acts as a capacitive component. Since the capacitance of the electric double layer is very large, the impedance at low frequencies is high. When the frequency of the AC voltage is 1 MHz or more, the dielectric component of the stimulus-responsive gel 24 and the inductive component of the entire system from the first electrode 22 to the impedance measuring unit 32 are affected. For this reason, the impedance is reduced. The frequency characteristics vary depending on the distance between the electrodes of the first electrode 22 and the electrode area. However, in order to obtain the impedance of the stimulus-responsive gel 24 with high accuracy, the impedance measurement should be performed with the AC voltage frequency set to 1 KHz to 1 MHz. desirable. Furthermore, it is desirable to measure impedance by setting the frequency of the AC voltage to 10 KHz to 1 MHz. From 10 KHz to 1 MHz, the influence of the capacitance component can be further reduced.

  FIG. 14 is a diagram showing the frequency characteristics of the phase difference of the current with respect to the voltage of the stimulus-responsive gel. In FIG. 14, the vertical axis represents the phase difference of the current with respect to the voltage of the stimulus-responsive gel 24, and the horizontal axis represents the frequency of the AC voltage output from the power supply unit 42. In the vertical axis, the center is 0 degree, and the upper side in the figure is higher than the lower side. The frequency on the horizontal axis is higher on the right side of the diagram than on the left side, and is a logarithmic scale. A second characteristic line 49 indicates the characteristics of the phase difference of the current with respect to the voltage of the stimulus-responsive gel 24 with respect to the frequency of the AC voltage. When the frequency of the AC voltage is 10 KHz or more and 1 MHz or less, the phase difference of the current with respect to the voltage of the stimulus-responsive gel 24 is 0 degree. Therefore, since the impedance of the stimulus-responsive gel 24 can be measured under the condition that the phase difference of the current with respect to the voltage is 0 degree by setting the frequency of the AC voltage to 10 KHz or more and 1 MHz or less, it is not necessary to acquire phase information. As a result, the impedance can be easily calculated. In the present embodiment, for example, the frequency of the AC voltage is set to 100 KHz.

  FIG. 15 is a diagram showing frequency characteristics of impedance of the stimulus-responsive gel and sweat. The vertical axis and horizontal axis in FIG. 15 are the same as those in FIG. A third characteristic line 50 indicates the impedance characteristic of the sweat 28 with respect to the frequency of the AC voltage. The sweat 28 is artificial sweat and is adjusted to be the same as the sweat component.

  The impedance measuring unit 32 switches the switch 44 to apply an AC voltage to the second electrode 23. Similarly to the first characteristic line 48, the third characteristic line 50 can also reduce the influence of the capacitive component and the inductive component by setting the frequency of the AC voltage to 10 KHz to 1 MHz.

  An output terminal 46 of the impedance measurement unit 32 is connected to the A / D conversion unit 33. Then, the impedance measuring unit 32 detects the impedance of the stimulus-responsive gel 24 and the sweat 28 and outputs an impedance signal to the A / D conversion unit 33. The A / D converter 33 converts the impedance signal into a data signal of digital data. The A / D converter 33 outputs impedance data to the conductivity calculator 40 via the input / output interface 35 and the data bus 36.

  The conductivity calculator 40 calculates conductivity from a data signal indicating impedance. The impedance measurement unit 32, the A / D conversion unit 33, the conductivity calculation unit 40, and the like constitute a measurement unit. The measurement unit measures the electrical conductivity between the first electrodes 22 and the electrical conductivity between the second electrodes 23.

The lactic acid value calculation unit 41 calculates the change rate of the weight of the stimulus responsive gel 24 using the conductivity of the stimulus responsive gel 24 and the conductivity of the sweat 28. Next, the lactic acid value calculation unit 41 calculates the concentration of lactic acid using the rate of change in weight of the stimulus-responsive gel 24 and the correlation table 38. FIG. 16 is a diagram showing the relationship between the conductivity ratio and the weight change rate of the stimulus-responsive gel. In FIG. 16, the vertical axis represents the weight change rate of the stimulus-responsive gel 24, and the horizontal axis represents the conductivity ratio of the stimulus-responsive gel 24 and the sweat 28. The conductivity of the stimulus-responsive gel 24 is σ _g and the conductivity of the sweat 28 is σ _S. The conductivity ratio on the horizontal axis is σ _g divided by σ _S.

  The relationship between the conductivity ratio and weight change rate in artificial sweat containing sodium lactate, sodium chloride, and potassium chloride is shown in the figure. As shown in the figure, even when the concentration of sodium chloride changes 5 times or 10 times, the relationship between the conductivity ratio and the weight change rate in artificial sweat does not change. Similarly, it has been confirmed that the relationship between the ratio of conductivity and the weight change rate in artificial sweat does not change even when the concentration of potassium chloride changes 5 to 10 times.

FIG. 17 is a diagram showing the relationship between the calculated value of conductivity and the weight change rate of the stimulus-responsive gel. In FIG. 17, the vertical axis represents the weight change rate of the stimulus-responsive gel 24, and the horizontal axis represents the calculated value using the stimulus-responsive gel 24, the conductivity and the conductivity of the sweat 28. The calculated value on the horizontal axis is σ _S / (σ _S −σ _g ). As shown in the figure, the weight change rate of the stimulus-responsive gel 24 and the calculated value have a linear relationship. Therefore, when the weight of the stimulus-responsive gel 24 is M _Gel and α and β are constants, M _Gel is expressed by the following equation.
M _Gel = ασ _S / (σ _S −σ _g ) + β (Formula 1)
Α and β in (Equation 1) are calculated in a preliminary experiment. Then, the change in the weight of the stimulus-responsive gel 24 can be calculated by substituting σ _g and σ _S at the time of measurement into (Equation 1).

  FIG. 18 is a graph showing the relationship between the sodium lactate concentration and the weight change rate of the stimulus-responsive gel. In FIG. 18, the vertical axis represents the weight change rate of the stimulus-responsive gel 24, and the horizontal axis represents the sodium lactate concentration. On the vertical axis, the upper side in the figure is higher than the lower side. On the horizontal axis, the value on the right side of the figure is higher than that on the left side. The fourth characteristic line 51 shows the relationship between the sodium lactate concentration and the weight change rate of the stimulus-responsive gel. The fourth characteristic line 51 is an arc-shaped curve, and shows that the weight change rate of the stimulus-responsive gel 24 increases as the sodium lactate concentration increases.

  The fourth characteristic line 51 is a line that changes when the component of the stimulus-responsive gel 24 is changed. Therefore, by calculating the fourth characteristic line 51 in a preliminary experiment, the sodium lactate concentration can be calculated using the calculated value of the weight change rate during measurement.

FIG. 19 is a diagram showing the relationship between the sodium lactate concentration and the calculated value. In FIG. 19, the vertical axis represents the sodium lactate concentration, and the horizontal axis represents the calculated value of σ _S / (σ _S −σ _g ). On the vertical axis, the upper side in the figure is higher than the lower side. On the horizontal axis, the value on the right side of the figure is higher than that on the left side. The fifth characteristic line 52 shows the relationship between the calculated value of σ _S / (σ _S −σ _g ) and the sodium lactate concentration. The fifth characteristic line 52 is an arc-shaped curve, which indicates that the sodium lactate concentration increases as the calculated value of σ _S / (σ _S −σ _g ) increases.

  The fifth characteristic line 52 is a line that changes by changing the components of the stimulus-responsive gel 24. Therefore, by calculating the fifth characteristic line 52 in a preliminary experiment, the sodium lactate concentration can be calculated using the calculated value of the weight change rate during measurement. The sodium lactate concentration can be calculated using either one of the fourth characteristic line 51 and the fifth characteristic line 52.

FIG. 20 is a diagram for explaining the table format of the correlation table. The correlation table 38 shown in FIG. 20 shows the fifth characteristic line 52. In the correlation table 38, the value of σ _S / (σ _S −σ _g ) and the value of sodium lactate concentration are set in pairs. The values of σ _S / (σ _S −σ _g ) are set at equal intervals, and the value of sodium lactate concentration corresponding to each value of σ _S / (σ _S −σ _g ) is set. Accordingly, the sodium lactate concentration can be calculated after calculating the value of σ _S / (σ _S −σ _g ).

  Next, a lactic acid value measuring method using the lactic acid value measuring apparatus 1 described above will be described. First, the subject 2 installs the lactic acid value measuring apparatus 1 on the subject 2. Then, the subject 2 secretes sweat 28 from the surface 2a to be examined. Thereby, a part of the sweat 28 is absorbed by the stimulus-responsive gel 24, and a part of the sweat 28 wets the second electrode 23.

  Next, the impedance measuring unit 32 applies an AC voltage to the first electrode 22 to detect a current flowing between the first electrodes 22. Then, the impedance measuring unit 32 outputs an impedance signal indicating the impedance of the stimulus responsive gel 24. Next, the impedance measurement unit 32 applies an AC voltage to the second electrode 23 to detect a current flowing between the second electrodes 23. Then, the impedance measuring unit 32 outputs an impedance signal indicating the impedance of the sweat 28.

  Next, the A / D converter 33 converts the impedance signal into digital data. Then, the impedance data is output to the conductivity calculator 40. Next, the conductivity calculator 40 calculates the conductivity of the stimulus-responsive gel 24 and the conductivity of the sweat 28 from the data signal indicating the impedance. Subsequently, the lactic acid value calculator 41 calculates the weight change rate of the stimulus-responsive gel 24 using the conductivity of the stimulus-responsive gel 24 and the conductivity of the sweat 28. Next, the lactic acid value calculation unit 41 calculates the concentration of lactic acid using the weight change rate of the stimulus-responsive gel 24 and the correlation table 38. Through the above process, the lactic acid value measuring apparatus 1 detects the concentration of lactic acid contained in the sweat 28.

As described above, this embodiment has the following effects.
(1) According to this embodiment, the lactic acid value measuring apparatus 1 includes the first detection unit 25, the second detection unit 26, the impedance measurement unit 32, and the conductivity calculation unit 40. In the first detection unit 25, the stimulus-responsive gel 24 is installed between the first electrodes 22. This stimulus-responsive gel 24 responds to the lactic acid of sweat 28. In the second detection unit 26, sweat 28 is installed between the second electrodes 23. The impedance measuring unit 32 and the conductivity calculating unit 40 measure the conductivity between the first electrodes 22. Further, the impedance measuring unit 32 and the conductivity calculating unit 40 measure the conductivity between the second electrodes 23.

  In addition to lactic acid, the sweat 28 contains components other than lactic acid. The stimulus-responsive gel 24 changes its conductivity in response to the lactic acid of the sweat 28. The impedance measuring unit 32 and the conductivity calculating unit 40 measure the conductivity between the first electrodes 22. The impedance measuring unit 32 and the conductivity calculating unit 40 measure the conductivity when the stimulus-responsive gel 24 that strongly reacts to the concentration of lactic acid contains sweat 28. On the other hand, there is a sweat 28 between the second electrodes 23 and there is no stimulus-responsive gel 24. The impedance measuring unit 32 and the conductivity calculating unit 40 measure the conductivity between the second electrodes 23 and measure the conductivity of the sweat 28.

  Therefore, by using the conductivity between the first electrodes 22 and the conductivity between the second electrodes 23, the lactic acid value measuring apparatus 1 determines the influence of the conductivity of components other than lactic acid from the conductivity between the first electrodes 22. Can be reduced. As a result, the concentration of lactic acid contained in the sweat 28 can be accurately measured.

  (2) According to the present embodiment, the lactic acid value measuring apparatus 1 includes the power supply unit 42 and the ammeter 43. The power supply unit 42 supplies an AC voltage between the first electrodes 22 and between the second electrodes 23. The ammeter 43 detects the current flowing between the first electrodes 22 and the current flowing between the second electrodes 23. Therefore, the impedance measuring unit 32 and the conductivity calculating unit 40 can measure the conductivity between the first electrodes 22 and the conductivity between the second electrodes 23.

  An electric double layer made of water molecules is formed on the surfaces of the first electrode 22 and the second electrode 23. And when the power supply part 42 applies a DC voltage between each electrode, since an electric double layer acts as an electric capacity, electrical conductivity cannot be measured accurately. In the present embodiment, the power supply unit 42 supplies an alternating voltage. Accordingly, since an alternating current flows between the electrodes, the influence of the electric double layer in the impedance measurement can be reduced.

  (3) According to the present embodiment, the lactic acid value measuring apparatus 1 includes the lactic acid value calculating unit 41 and the memory 31. The memory 31 stores a correlation table 38, which shows the relationship between the conductivity between the first electrodes 22, the conductivity between the second electrodes 23, and the concentration of lactic acid. The lactic acid value calculation unit 41 calculates the concentration of lactic acid contained in the sweat 28. At this time, the lactic acid value calculating unit 41 uses the conductivity between the first electrodes 22 and the conductivity between the second electrodes 23 measured by the impedance measuring unit 32 and the conductivity calculating unit 40 and the correlation table 38.

  Also when the relationship between the conductivity between the first electrodes 22 and the conductivity between the second electrodes 23 and the concentration of lactic acid is non-linear, the correlation table 38 shows that the conductivity between the first electrodes 22 and the second electrode 23 The relationship between electrical conductivity and lactic acid concentration can be shown. Therefore, the impedance measuring unit 32 and the conductivity calculating unit 40 can surely calculate the concentration of lactic acid contained in the sweat 28.

  (4) According to the present embodiment, the frequency of the AC voltage output from the power supply unit 42 is 10 KHz to 1 MHz. When the frequency of the AC voltage is less than 10 KHz, it is affected by the electric double layer formed at the interface between the electrode and the liquid to be inspected, so that the accuracy of the measured conductivity is lowered. When the frequency of the AC voltage exceeds 1 MHz, it is affected by the capacitance component of the stimulus-responsive gel 24, so the accuracy of the measured conductivity is lowered. When the frequency of the AC voltage is 10 KHz or more and 1 MHz or less, it is difficult to be influenced by the electric double layer and the capacitance component of the stimulus-responsive gel 24, so that the conductivity can be accurately measured.

  (5) According to this embodiment, the 1st electrode 22 is installed on the board | substrate 14 of the sensor module 7, and the 1st electrode 22 has a comb-tooth shape. A stimulus-responsive gel 24 is installed on the first electrode 22. Accordingly, since the stimulus-responsive gel 24 is positioned between the comb-shaped first electrodes 22, the impedance measuring unit 32 and the conductivity calculating unit 40 can measure the conductivity between the first electrodes 22. . And since the 1st detection part 25 has the simple structure which piles up and installs the 1st electrode 22 and the stimulus responsive gel 24 on the board | substrate 14, the lactic acid value measuring apparatus 1 can be manufactured with sufficient productivity.

  (6) According to the present embodiment, the stimulus-responsive gel 24 is thicker than the first electrode 22. Accordingly, since the first electrode 22 is not exposed from the stimulus-responsive gel 24, the first detector 25 can stably measure the conductivity of the stimulus-responsive gel 24 between the first electrodes 22.

  (7) According to the present embodiment, the sensor module 7 on which the first detection unit 25 is installed is detachably installed on the circuit unit 11 on which the impedance measurement unit 32 is installed. Therefore, by changing the stimulus-responsive gel 24, the stimulus-responsive gel 24 can be easily transferred to a state not containing lactic acid.

(Second Embodiment)
Next, an embodiment of a sensor module installed in the lactic acid value measuring apparatus will be described with reference to FIGS. This embodiment is different from the first embodiment in that the structure of the sensor module is different. Note that description of the same points as in the first embodiment is omitted.

  FIG. 21 is a schematic perspective view showing the structure of the sensor module. That is, in this embodiment, as shown in FIG. 21, the sensor module 56 installed in the lactic acid value measuring device 55 includes a first substrate 57 and a second substrate 58. The first substrate 57 and the second substrate 58 are arranged to face each other, and a stimulus-responsive gel 59 is installed between the first substrate 57 and the second substrate 58.

  FIG. 22 is a schematic side view showing the structure of the sensor module. As shown in FIG. 22, the first positive electrode 60a is provided on the + Y direction side on the first substrate 57, and the second positive electrode 61a is provided on the −Y direction side. The first sub electrode 60b is provided on the + Y direction side on the second substrate 58, and the second sub electrode 61b is provided on the −Y direction side. The first positive electrode 60a and the first sub electrode 60b are arranged to face each other, and the first positive electrode 60a and the first sub electrode 60b constitute the first electrode 60. Similarly, the second positive electrode 61a and the second sub electrode 61b are disposed to face each other, and the second positive electrode 61a and the second sub electrode 61b constitute the second electrode 61.

  The stimulus-responsive gel 59 is sandwiched between the first electrodes 60, and the first detector 62 is configured by the stimulus-responsive gel 59, the first electrode 60, and the like. Further, the second detection unit 63 is configured by the second electrode 61 and the like. When the sweat 28 enters between the first substrate 57 and the second substrate 58, the sweat 28 enters between the stimulus-responsive gel 59 and the second electrode 61.

  Thereby, the stimulus-responsive gel 59 swells. The impedance measuring unit 32 detects the impedance of the stimulus-responsive gel 59 by applying an AC voltage between the first electrodes 60. Further, the impedance measuring unit 32 detects the impedance of the sweat 28 by applying an AC voltage between the second electrodes 61.

  FIG. 23 is a schematic plan view showing the structure of the sensor module. As shown in FIG. 23, the area of the stimulus-responsive gel 59 is wider than that of the first electrode 60. The stimulus responsive gel 59 covers the first electrode 60. Even when the stimulus-responsive gel 59 contracts, the area of the stimulus-responsive gel 59 is larger than that of the first electrode 60. The stimulus responsive gel 59 covers the first electrode 60.

  Therefore, even when the stimulus-responsive gel 59 changes due to contraction and expansion, the area where the first electrode 60 contacts the stimulus-responsive gel 59 can be prevented from changing. As a result, it is possible to suppress a decrease in the measurement accuracy of the conductivity between the first electrodes 60 due to the contraction and expansion of the stimulus-responsive gel 59.

  The distance between the first positive electrode 60a and the first sub electrode 60b is preferably narrow. By narrowing the electrode interval, the response speed of the stimulus-responsive gel 59 with respect to changes in the concentration of lactic acid can be increased. Further, the impedance can be accurately measured by narrowing the electrode interval. The distance between the first positive electrode 60a and the first sub electrode 60b is preferably 100 μm or less.

(Third embodiment)
Next, an embodiment of a sensor module installed in the lactic acid value measuring apparatus will be described with reference to FIGS. This embodiment is different from the first embodiment in that the structure of the sensor module is different. Note that description of the same points as in the first embodiment is omitted.

  FIG. 24 is a schematic side view showing the structure of the sensor module. That is, in this embodiment, the sensor module 67 installed in the lactic acid value measuring device 66 includes a substrate 68 as shown in FIG. A first electrode 69, a second electrode 70, and a stimulus responsive gel 71 are installed on the substrate 68. The first electrode 69 is covered with a stimulus-responsive gel 71. The first detection unit 72 is configured by the stimulus-responsive gel 71, the first electrode 69, and the like. Further, the second detection unit 73 is configured by the second electrode 70 and the like.

  The stimulus-responsive gel 71 is thicker than the first electrode 69. Accordingly, since the first electrode 69 is not exposed from the stimulus responsive gel 71, the first detector 72 can stably measure the impedance of the stimulus responsive gel 71 between the first electrodes 69.

  FIG. 25 is a schematic plan view showing the structure of the sensor module. As shown in FIG. 25, in the 1st detection part 72, the 1st positive electrode 69a and the 1st subelectrode 69b which comprise the 1st electrode 69 are arrange | positioned alternately. A stimulus-responsive gel 71 is installed so as to cover the first electrode 69. In the second detection unit 73, the second positive electrode 70a and the second sub electrode 70b constituting the second electrode 70 are alternately arranged.

  When the sweat 28 enters between the substrate 68 and the surface 2 a to be inspected, the sweat 28 enters between the stimulus-responsive gel 71 and the second electrode 70. Thereby, the stimulus-responsive gel 71 swells. The impedance measuring unit 32 detects the impedance of the stimulus-responsive gel 71 by applying an AC voltage between the first electrodes 69. Further, the impedance measuring unit 32 detects the impedance of the sweat 28 by applying an AC voltage between the second electrodes 70. Subsequent measurement procedures are the same as those in the first embodiment, and a description thereof will be omitted. The number of the first electrodes 69 and the second electrodes 70 is preferably large. The S / N ratio in the detected impedance value can be increased.

Note that the present embodiment is not limited to the above-described embodiment, and various changes and improvements can be added by those having ordinary knowledge in the art within the technical idea of the present invention. A modification will be described below.
(Modification 1)
In the first embodiment, the stimulus-responsive gel 24 responded to lactic acid contained in the sweat 28. In addition, a stimulus-responsive gel that reacts with substances such as sodium chloride, potassium chloride, magnesium, urea, and the like may be used. The concentration of the substance to which the stimulus-responsive gel reacts can be detected. The solvent of the substance to which the stimulus-responsive gel reacts is not limited to the sweat 28, and various solutions can be tested. For example, the concentration of a specific substance contained in blood, saliva, or urine can be detected.

(Modification 2)
In the first embodiment, the lactic acid value measuring device 1 is a portable device. You may make it the apparatus installed on a desk. Then, the operator may supply the liquid to be inspected to the lactic acid value measuring apparatus. A plurality of sensor modules 7 may be installed. The density | concentration of the specific substance in a some to-be-tested liquid can be test | inspected simultaneously.

(Modification 3)
In the first embodiment, in the correlation table 38, the value of σ _S / (σ _S −σ _g ) and the value of sodium lactate concentration are set in pairs. In addition, the correlation table may be set by pairing the value of σ _g / σ _{S and} the value of sodium lactate concentration. Also at this time, the lactic acid value can be calculated from the conductivity.

  DESCRIPTION OF SYMBOLS 1,55,66 ... Lactic acid value measuring apparatus as a measuring apparatus, 14,68 ... Board | substrate, 22,60 ... 1st electrode, 23 ... 2nd electrode, 24,59,71 ... Stimulus responsive gel, 25 ... 1st Detection unit, 26 ... second detection unit, 28 ... sweat as test liquid, 31 ... memory as storage unit, 32 ... impedance measurement unit as measurement unit, 33 ... A / D conversion unit as measurement unit, 38 ... Correlation table, 40 ... Conductivity calculation unit as measurement unit, 41 ... Lactic acid value calculation unit as calculation unit, 42 ... Power supply unit, 43 ... Ammeter.

Claims (8)

A first detection unit in which a stimulus-responsive gel that expands or contracts by stimulation with a predetermined component of the liquid to be inspected is installed between the first electrodes;
A second detector for installing the liquid to be inspected between the second electrodes;
And a measuring unit that measures the electrical conductivity between the first electrodes and the electrical conductivity between the second electrodes. The measuring device according to claim 1,
The measurement unit includes a power supply unit that supplies an AC voltage between the first electrodes and between the second electrodes, an ammeter that detects a current flowing between the first electrodes and a current flowing between the second electrodes, A measuring apparatus comprising: The measuring device according to claim 1 or 2,
A storage unit for storing a correlation table indicating a relationship between the conductivity between the first electrodes and the conductivity between the second electrodes and the amount of the predetermined component;
A calculation unit that calculates the concentration of lactic acid contained in the test liquid using the conductivity between the first electrodes measured by the measurement unit, the conductivity between the second electrodes, and the correlation table. A measuring device. The measuring device according to claim 2,
The frequency of the AC voltage is 10 kHz to 1 MHz. It is a measuring device as described in any one of Claims 1-4,
In the first detection unit, the stimulus-responsive gel is sandwiched between the first electrodes facing each other,
The measurement apparatus, wherein the stimulus-responsive gel has a larger area than the first electrode in a state where the stimulus-responsive gel is contracted. It is a measuring device as described in any one of Claims 1-4,
The first detection unit includes a substrate,
The first electrode disposed in a comb shape on the substrate;
And a stimulus-responsive gel placed on the first electrode. The measuring device according to claim 6,
The measurement apparatus characterized in that the stimulus-responsive gel is thicker than the first electrode. The measurement apparatus according to any one of claims 1 to 6,
The measurement apparatus, wherein the first detection unit is detachably attached to the measurement unit.