JP7322311B1 - Electrochemical sensor and method of manufacturing electrochemical sensor - Google Patents

Abstract

A test liquid can be uniformly and continuously supplied to each sensor electrode while insulating a plurality of sensor electrodes other than the detection surface. An electrochemical sensor (1) used for measuring the concentration of a specific component in a test liquid, comprising a protective member (30) having a plurality of openings (31) and individually arranged in the plurality of openings (31). A plurality of sensor electrodes 20 and a support member 10 supporting the protection member 30 and the plurality of sensor electrodes 20 are provided, and the support member 10 supports the protection member 30 and the plurality of sensor electrodes 20. Thus, the detection surfaces 20a of the plurality of sensor electrodes 20 and the surface 30a of the protective member 30 form a flush structure. [Selection drawing] Fig. 2

Description

The present invention relates to electrochemical sensors and methods of manufacturing electrochemical sensors.

It has been proposed to electrochemically measure the ozone concentration of ozone water using a conductive diamond electrode (see, for example, Patent Document 1).

WO2020/091033

In electrochemical sensors, in order to ensure the reliability of electrochemical measurements, electrochemical It is preferable to insulate areas other than the electrode surface so that no reaction occurs. If insulation other than the electrode surface is performed by, for example, air insulation using a protective frame (frame structure) surrounding the sensor electrode, the electrode surface will not be contaminated.

However, when a frame structure is applied to multiple sensor electrodes, if a step (uneven structure) occurs on the surface of each electrode or on the top surface of the protective frame, etc., the presence of the uneven structure may hinder the diffusion of the substance to be measured. It may interfere. In that case, the current peak height at the time of linear sweep voltammetry (LSV) measurement is not sufficiently obtained, and even if the sensor electrode has high detection sensitivity, such as a conductive diamond electrode, its characteristics cannot be utilized. It can disappear.

INDUSTRIAL APPLICABILITY The present disclosure can insulate portions other than the detection surface of a plurality of sensor electrodes, and even in that case, it is possible to optimize the supply of the sample liquid to each sensor electrode, thereby improving the electrochemical measurement. Provide technology that enables reliability, high sensitivity, etc.

According to one aspect of the present disclosure,
An electrochemical sensor used to measure the concentration of a specific component in a test solution,
a protective member having a plurality of openings;
a plurality of sensor electrodes individually arranged in the plurality of openings;
a support member that supports the protective member and the plurality of sensor electrodes,
With the support member supporting the protection member and the plurality of sensor electrodes, the detection surface of the plurality of sensor electrodes on the side facing the support substrate and the plurality of openings of the protection member An electrochemical sensor is provided in which the surface facing the support substrate forms a flush structure.

According to the technique of the present disclosure, it is possible to optimize the supply of the sample liquid to each sensor electrode while insulating the surfaces other than the detection surfaces of the plurality of sensor electrodes. It becomes possible to realize high reliability and high sensitivity of the measurement.

1 is an exploded perspective view showing a schematic configuration example of an electrochemical sensor according to an embodiment of the present disclosure; FIG. FIG. 2 is a side cross-sectional view showing a configuration example of a main part in the electrochemical sensor of FIG. 1; FIG. 2 is a flow chart showing an example of the procedure of a method for manufacturing an electrochemical sensor according to an embodiment of the present disclosure;

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following description is an example, and the present disclosure is not limited to the illustrated aspects.

(1) Configuration of electrochemical sensor The electrochemical sensor described in this embodiment is used to measure the concentration of a specific component in a sample liquid. The test liquid is, for example, ozone water in which ozone (O ₃ ) is dissolved in water (such as tap water). The specific component is, for example, ozone dissolved in ozone water. Concentration measurements are performed using, for example, linear sweep voltammetry (LSV). That is, the electrochemical sensor in this embodiment can measure the ozone concentration ( _O3 concentration) in ozone water using LSV.

(overall structure)
In order to measure the ozone concentration in ozone water, the electrochemical sensor according to this embodiment is configured as described below.
FIG. 1 is an exploded perspective view showing a schematic configuration example of an electrochemical sensor according to this embodiment. FIG. 2 is a side cross-sectional view showing a configuration example of a main part in the electrochemical sensor of FIG.
As shown in FIG. 1 and FIG. 2, the electrochemical sensor 1 is generally composed of a supporting substrate 10, a sensor electrode 20, and a protective member 30. As shown in FIG.

(support substrate)
The support substrate 10 supports the sensor electrodes 20 and the protective member 30, and is formed as a strip-shaped sheet-like (plate-like) member extending in the longitudinal direction. At least one end of the strip may be arc-shaped, for example. The support substrate 10 is made of an insulating material. Examples of insulating materials include composite resins, ceramics, glass, plastics, glass epoxy resins, non-woven fabrics, paper, and paper epoxy. The material forming the support substrate 10 may be, for example, a combustible material or a biodegradable material. However, the material forming the support substrate 10 should have physical strength and mechanical strength to the extent that it will not be bent or damaged during the measurement of the _O3 concentration in the ozone water, for example. do. In this embodiment, the support substrate 10 is preferably made of, for example, a glass epoxy resin, and is preferably configured to have flexibility.

On one main surface of the support substrate 10 (specifically, on the surface on which the sensor electrodes 20 are arranged), the sensor electrodes 20 are arranged on one end side (for example, the side where the edge is formed in an arc shape). An electrode pad 11 is provided as a region. The electrode pads 11 are spaced apart at a plurality of locations (for example, three locations) so as to correspond to the number of sensor electrodes 20 to be described later. A connection terminal 12 for electrically connecting to a measuring device (for example, a potentiostat), which will be described later, is provided on the other end side of the main surface. As with the electrode pads 11 , a plurality (for example, three) of the connection terminals 12 are provided corresponding to the number of the sensor electrodes 20 . Wirings (electrical wirings) 13 are provided on the main surface to electrically connect to the electrode pads 11 on one end side and to electrically connect to the connection terminals 12 on the other end side. Similarly to the electrode pads 11 and the connection terminals 12, a plurality of wirings 13 (for example, three wirings) are provided corresponding to the number of the sensor electrodes 20, and are spaced apart from each other. Through such a wiring 13, each electrode pad 11 and each connection terminal 12 are individually connected to ensure conduction. That is, the electrode pads 11, the wirings 13 and the connection terminals 12 assigned to the respective sensor electrodes 20 are provided on the support substrate 10, and the electrode pads 11 and the connection terminals 12 are individually connected via the wirings 13. It is designed to be electrically connected.

Materials for forming the electrode pads 11, the connection terminals 12 and the wirings 13 include, for example, copper (Cu), gold (Au), platinum (Pt), silver (Ag), palladium (Pd), aluminum (Al), iron ( Fe), nickel (Ni), chromium (Cr), titanium (Ti), alloys thereof, oxides thereof, carbon (C), or laminates thereof.

On the main surface of the support substrate 10, the wiring 13 is covered with an insulating protective film 14 except for the area where the protective member 30 is arranged and the area where the connection terminals 12 are formed. The insulating protective film 14 can be formed of, for example, an insulating resin material (eg, polyethylene terephthalate (PET)), a solder resist, an insulating adhesive sheet, an insulating adhesive, or the like.

(Sensor electrode)
The sensor electrode 20 is arranged on the electrode pad 11 of the support substrate 10 and functions as an electrode for measuring the ozone concentration in the ozone water. For this reason, the sensor electrode 20 is configured as a self-standing body having a detection surface that comes into contact with ozone water, which is the test liquid. The term "self-standing body" as used herein means a solid body that can stand on its own without support, and has a shape such as a flat plate, disk, cube, rectangular parallelepiped, or polyhedron. As described above, the sensor electrode 20 is not a thin film formed on the support substrate 10, but is a self-supporting body configured separately from the support substrate 10, so that the flexible support substrate 10 can be used, and a chip can be used. The shaped sensor electrode 20 can be easily mass-produced.

The sensor electrode 20 is composed of three electrodes, a working electrode 21, a counter electrode 22, and a reference electrode 23, if the measurement of the ozone concentration in the ozone water is performed by the three-electrode method. In other words, the sensor electrode 20 is a sensor composed of three electrodes, the working electrode 21 , the counter electrode 22 and the reference electrode 23 .

These working electrode 21, counter electrode 22 and reference electrode 23 (hereinafter also referred to as "the respective electrodes 21, 22 and 23") can be configured in the same shape. The term "same shape" as used herein means that each chip has the same planar shape, that is, that the detection surface that functions as an electrode has the same planar shape and area, and that the figures drawn by each planar shape are congruent. means. The planar shape of the chip can be, for example, a rectangular shape having long sides arranged along the longitudinal direction of the support substrate 10, but is not limited to this, and may be a square shape or a circular shape. do not have.

The plane area of each of the electrodes 21, 22, and 23 is not particularly limited, but is, for example, 1 mm ² or more, preferably 4 mm ² or more, more preferably 10 mm ² or more, and still more preferably 20 mm ^{2 or} more, It is preferably 100 mm ² or less, more preferably 50 mm ² or less. The “planar area” referred to here is the area when each electrode 21, 22, 23 is viewed from above the main surface of the support substrate 10 in the vertical direction, and the surface that contributes to the detection of ozone in the ozone water ( detection surface).
If the plane area of each of the electrodes 21, 22, and 23 is 1 mm ² or more, the electrodes 21, 22, and 23 can be produced stably and easily with high accuracy, and deterioration in handling and mounting stability can be prevented. can also be suppressed.
If the plane area of each of the electrodes 21, 22, 23 is 100 mm ² or less, the electrochemical sensor 1 can be prevented from becoming large, that is, the electrochemical sensor 1 can be easily obtained in a small size. Furthermore, by setting the plane area of each electrode 21, 22, 23 to 50 mm ² or less, it is possible to reliably avoid an increase in the size of the electrochemical sensor 1 while obtaining the highly sensitive electrochemical sensor 1 .

The arrangement of the electrodes 21, 22, and 23 on the support substrate 10 is not particularly limited, but for example, they may be arranged at symmetrical positions. The symmetrical positions include the following.
Specifically, the electrodes 21 , 22 , 23 are arranged at line-symmetrical positions with respect to a virtual line (not shown) extending along the longitudinal direction of the support substrate 10 . In that case, one of the electrodes 21, 22, 23 (for example, the electrode 21) has its center of gravity or center point in the planar shape located on the virtual line, and the other two (for example, the electrodes 22, 23) are positioned on the virtual line. 23) are distributed to symmetrical positions across the imaginary line.
In addition to the above-described line-symmetrical positions, the electrodes 21, 22, and 23 are arranged at three-fold symmetrical positions about a predetermined reference point (not shown) on the support substrate 10. You may make it The predetermined reference point is a virtual point preset on the virtual line described above. In addition, the three-fold symmetry means that at least the figure (for example, the planar shape of each electrode 21, 22, 23) is rotated by 120° around the reference point. ) is the symmetry in which the centroids or central points of In the case of three-fold symmetry, the center of gravity of each electrode 21, 22, 23 or the line connecting the center points forms an equilateral triangle.

In the present embodiment, for each of the electrodes 21, 22, and 23, for example, the working electrode 21 is arranged on a virtual line in the vicinity of the tip-side edge (for example, arc-shaped edge) of the support substrate 10. The counter electrode 22 and the reference electrode 23 are arranged so as to be distributed to symmetrical positions with respect to the imaginary line on the side away from the distal end edge. With such an arrangement, the working electrode 21, the counter electrode 22 and the reference electrode 23 are arranged in positions that are axially symmetrical and three-fold symmetrical.

In the present embodiment, for each of the electrodes 21, 22, and 23, the tip end side of the support substrate 10 is made to function as the working electrode 21, and both sides thereof are made to function as the counter electrode 22 and the reference electrode 23, respectively. However, it is not necessarily limited to such an arrangement mode. In other words, how the working electrode 21, the counter electrode 22, and the reference electrode 23 are arranged is not limited to a specific mode.
Also, the function of each electrode 21, 22, 23 (that is, at which position to function as the working electrode 21, the counter electrode 22, or the reference electrode 23) does not necessarily have to be fixed; It may be possible to replace them as appropriate (for example, over time). However, if the functions are interchanged, it is desirable that the electrodes 21, 22, and 23 are arranged at the symmetrical positions described above.

For each electrode 21, 22, 23 so arranged, all three electrodes, including at least the working electrode 21 and the counter electrode 22, preferably the reference electrode 23, are respectively boron-doped diamond electrodes (hereinafter "BDD electrodes"). ”). That is, preferably, the three electrodes of working electrode 21, counter electrode 22 and reference electrode 23 can be BDD electrodes. However, if at least the working electrode 21 and the counter electrode 22 are BDD electrodes, the reference electrode 23 may be, for example, a silver (Ag) electrode or a metal electrode such as an Ag electrode whose surface is silver chloride (AgCl). .

The BDD electrode is an electrochemical electrode made of a diamond film doped with boron at a high concentration to impart high conductivity.
In this embodiment, the BDD electrode includes an electrode film 24 made of a polycrystalline diamond film or the like, and a conductive substrate (hereinafter also simply referred to as "substrate") 25. A chip in which these are laminated It is a shaped electrode (electrode tip). It is configured as a vertical electrode that conducts from the back surface of the substrate 25 (that is, the surface opposite to the surface on which the electrode film 24 is provided).

The electrode film 24 is made of polycrystalline diamond. Specifically, the electrode film 24 is a polycrystalline film (polycrystalline diamond film) composed of diamond crystals containing boron (B) as a dopant, that is, diamond crystals having p-type conductivity. A diamond crystal is a crystal in which carbon (C) atoms are arranged in a pattern called a diamond crystal structure. Alternatively, the electrode film 24 may be a B-doped diamond-like carbon (DLC) film. The B concentration in the electrode film 24 can be measured by secondary ion mass spectrometry (SIMS), and can be, for example, 1×10 ¹⁹ cm ⁻³ or more and 5×10 ²² cm ⁻³ or less.

The electrode film 24 is provided on one of the two main surfaces of the substrate 25 . In this specification, the main surface of the substrate 25 on which the electrode film 24 is provided is also referred to as "the crystal growth surface of the substrate 25". The electrode film 24 is provided over the entire crystal growth surface of the substrate 25 . The electrode film 24 causes a predetermined electrochemical reaction (for example, oxidation-reduction reaction of ozone) on the surface (exposed surface).

The electrode film 24 can be grown (deposited, synthesized) by a chemical vapor deposition (CVD) method, a physical vapor deposition (PVD) method, or the like. Examples of the CVD method include hot filament CVD using a tungsten filament, plasma CVD, and the like, and examples of the PVD method include an ion beam method and an ionization vapor deposition method. The thickness of the electrode film 24 can be, for example, 0.5 μm or more and 10 μm or less, preferably 1 μm or more and 6 μm or less, more preferably 2 μm or more and 4 μm or less.

As the substrate 25, a flat substrate made of a low resistance material is used. As the substrate 25, a substrate composed mainly of silicon (Si) and containing a p-type dopant such as boron (B) at a predetermined concentration, for example, a p-type single crystal Si substrate can be used. A p-type polycrystalline Si substrate can also be used as the substrate 25 . The B concentration in the substrate 25 is, for example, 5×10 ¹⁸ cm ⁻³ or more and 1.5×10 ²⁰ cm ⁻³ or less, preferably 5×10 ¹⁸ cm ⁻³ or more and 1.2×10 ²⁰ cm ^{−3 or} less. can be done. By keeping the B concentration in the substrate 25 within the above range, it is possible to reduce the specific resistance of the substrate 25 while avoiding a decrease in manufacturing yield and deterioration in performance of the substrate 25 .

The thickness of the substrate 25 is not particularly limited, but is, for example, 150 μm or more and 1 mm or less. By setting the thickness of the substrate 25 within the above range, the handling of the substrate 25 can be stabilized. Although the upper limit of the thickness of the substrate 25 is not particularly limited, the thickness of a Si substrate generally available on the market at present is a single crystal Si substrate having a diameter of 12 inches and having a thickness of about 775 μm. Therefore, the upper limit of the thickness of the substrate 25 in the current technology can be set to about 775 μm, for example.

As the substrate 25, a substrate other than a substrate composed of Si as a main element (Si substrate) can be used. For example, as the substrate 25, a substrate configured using a compound of Si such as a silicon carbide substrate (SiC substrate) can be used.

It is also conceivable to use a metal substrate composed mainly of niobium (Nb), molybdenum (Mo), titanium (Ti), or the like as the substrate 25 . However, it is preferable to use a Si substrate as the substrate 25 because leakage current is likely to occur when a metal substrate is used.

The sensor electrodes 20 (that is, the working electrode 21, the counter electrode 22, and the reference electrode 23) configured as described above are respectively placed on the electrode pads 11 of the support substrate 10 via the conductive bonding material 26 having conductivity. are placed in

The conductive bonding material 26 is composed of, for example, a conductive adhesive sheet or a conductive adhesive. That is, in the present embodiment, the sensor electrode 20 is bonded to the electrode pad 11 using, for example, a conductive adhesive sheet or a conductive adhesive, thereby physically connecting the sensor electrode 20 and the electrode pad 11 together. and electrically connected. The conductive bonding material 26 is not limited to a specific adhesive sheet or adhesive as long as it can bond the sensor electrode 20 and the electrode pad 11 while having conductivity. It is preferable not to contain volatile organic components having a molecular weight of 100 or more.

The electrical resistivity of the conductive bonding material 26 is preferably, for example, 0.1 kΩ·m or less. Such an electrical resistivity is very preferable for ensuring conduction between the sensor electrode 20 and the electrode pad 11 .

The planar size of the conductive bonding material 26 is preferably larger than the planar size of the upper surface of the electrode pad 11 (that is, the surface in contact with the conductive bonding material 26). The "planar size" as used herein means at least one of the size of a planar shape (for example, the length of one side of a quadrangle, the length of a diameter of a circle, etc.) or the area of a planar shape. Specifically, for example, the conductive bonding material 26 having a side length of 1.9 mm is used for the electrode pad 11 having a square side length of 1.6 mm. With such a configuration, even if the position of the conductive bonding material 26 is not strictly controlled when arranging the conductive bonding material 26 on the electrode pad 11 (even if there is a positional deviation within the allowable tolerance), the electrode pad 11 can be positioned. Since the entire upper surface can be covered with the conductive bonding material 26, the overlapping area between the sensor electrode 20 and the electrode pad 11 is not impaired, and as a result, the space between the sensor electrode 20 and the electrode pad 11 is kept. It is very preferable in terms of ensuring electrical continuity.

On the other hand, the planar size of the conductive bonding material 26 is preferably smaller than the planar size of the bottom surface of the sensor electrode 20 (eg, the back surface of the substrate 25 in the case of a BDD electrode). Specifically, for example, the conductive bonding material 26 having a side length of 1.9 mm is used for the square sensor electrode 20 having a side length of 2.0 mm. With such a configuration, when the sensor electrode 20 is arranged on the electrode pad 11 with the conductive bonding material 26 interposed therebetween, the bottom surface of the sensor electrode 20 and the top surface of the support substrate 10 near the edge of the sensor electrode 20 are separated from each other. A spaced region (gap) 32a located outside the outer edge of the conductive bonding material 26 is formed between the . For example, when the planar area of the conductive bonding material 26 is smaller than the bottom area of the sensor electrode 20 , the spaced region 32 a is formed around the entire edge of the sensor electrode 20 so as to surround the outer edge of the conductive bonding material 26 . is formed so as to be continuous over the The significance of the existence of the spacing region 32a will be described later in detail.

(Protection member)
The protective member 30 is arranged on the support substrate 10 and used in the same manner as the electrodes 21, 22, and 23 described above. However, the protection member 30 has a plurality of openings 31 formed in planar view shapes corresponding to the respective electrodes 21 , 22 , 23 . Here, the "corresponding plan view shape" means a shape (for example, a similar shape) that can be identified with the plan view shape of each of the electrodes 21, 22, and 23. As shown in FIG. The protection member 30 is arranged on the support substrate 10 with the electrodes 21 , 22 , 23 individually positioned within the plurality of openings 31 . Thereby, when the protection member 30 is placed on the support substrate 10, the protection member 30 is arranged so as to surround the electrodes 21, 22, and 23 while exposing the detection surfaces 20a of the electrodes 21, 22, and 23. become.

Each opening 31 in the protective member 30 has a predetermined It is formed to have air gaps 32 spaced apart. Details of the gap 32 will be described later.

The protective member 30 is made of an insulating material. This is to prevent the function of the sensor electrode 20 from being adversely affected. Moreover, the protection member 30 is preferably made of a material having water repellency. This is because the water repellency is considered to contribute to the effect of suppressing penetration of ozone water, which will be described later. Materials for forming such a protective member 30 include, for example, polyimide (PI), polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), polystyrene (PS), polycarbonate (PC), PET, water-repellent coated paper, Examples include impregnated paper and Yupo paper. In this embodiment, the protective member 30 is made of PET, for example.

The protective member 30 is arranged on the support substrate 10 via an insulating bonding material 33 having insulating properties.

The insulating bonding material 33 is composed of, for example, an insulating adhesive sheet or an insulating adhesive. That is, in the present embodiment, the protective member 30 is attached to the support substrate 10 using, for example, an insulating adhesive sheet or an insulating adhesive, thereby physically separating the protective member 30 and the support substrate 10. is intended to be joined to The insulating bonding material 33 is not limited to a specific adhesive sheet or adhesive as long as it can bond the protective member 30 and the support substrate 10 while having insulation. It is preferable not to contain volatile organic components having a molecular weight of 100 or more.

The insulating bonding material 33 is formed in a plan view shape corresponding to the protective member 30 . Therefore, a plurality of openings (not shown) are also formed in the insulating bonding material 33 so as to correspond to the plurality of openings 31 in the protective member 30 .

The plane size of each opening in the insulating bonding material 33 is preferably larger than the plane size of the opening 31 in the protective member 30 . Specifically, for example, an opening having a side length of 2.3 mm is formed in the insulating bonding material 33 with respect to the opening 31 in the protective member 30 having a square side length of 2.2 mm. keep forming. With such a configuration, when the protective member 30 is arranged on the support substrate 10 with the insulating bonding material 33 interposed therebetween, a A spaced region (gap) 32b located outside the inner wall surface of the opening 31 is formed. For example, if the plane area of the opening is larger than the plane area of the opening 31, the spaced region 32b is formed along the inner wall surface of the opening 31 so as to be continuous along the entire circumference of the opening 31. . The significance of existence of the spaced region 32b will be described later in detail.

The protective member 30 arranged on the support substrate 10 via the insulating bonding material 33 does not need to cover the entire support substrate 10, and is arranged so as to cover the entire sensing area set on the support substrate 10. It just needs to be configured. The “sensing region” is a range within a predetermined distance L from the tip of the support substrate 10 including the locations where the electrodes 21, 22, and 23 are arranged, and is the main region to which the test liquid, ozonated water, is supplied. . The range of the predetermined distance L includes at least the area between each of the electrodes 21, 22, and 23 (inside the respective arrangement locations), and in the direction outside from the respective arrangement locations, the distance from the outer edge of the arrangement location to each A region having a length exceeding the length of the short sides of the electrodes 21, 22, and 23 is included.

Thus, if the protective member 30 covers the entire sensing region, the upper surface side of the sensing region (that is, the surface side to which the ozone water is supplied) is the surface 30a of the protective member 30, which is a single component. , the detection surface 20a of each of the electrodes 21, 22, 23 positioned within the opening 31 of the protective member 30, and the gap 32 formed therebetween. That is, in the sensing area, the surface 30a of the protective member 30 without a step covers the entire area between the detection surfaces 20a of the electrodes 21, 22, and 23 except for the gap 32. FIG.

(void)
A gap 32 formed between the detection surface 20a of each electrode 21, 22, 23 and the surface 30a of the protective member 30 is a space that does not contain other members. That is, the space 32 is not filled with anything, and an air layer (air insulating layer) is formed.

When the spaced regions 32 a and 32 b described above are formed, the spaced regions 32 a and 32 b are arranged so as to communicate with the gap 32 . In other words, an air layer (air insulating layer) is formed in the spaced regions 32a and 32b in the same way as in the gap 32. As shown in FIG.

By forming such an air layer, for example, at least a part of the side surface of each electrode 21 , 22 , 23 is exposed in the gap 32 .

In addition, when ozone water is supplied to each of the electrodes 21, 22, and 23, at least the surface tension of the ozone water generated in the gap 32 and the repulsive force of the air confined in the gap 32 are Either one is formed to suppress entry of ozone water into the gap 32 . The repulsive force of the air trapped within the void 32 can be caused by the lack of escape routes for the air within the void 32 . With such a configuration, contact of the ozone water with the side surfaces of the electrodes 21, 22, and 23 can be suppressed.

The effect of suppressing the permeation of ozonized water is determined by various factors such as the distance between the gaps 32 (distances between the openings 31 and the electrodes 21, 22, and 23), the aspect ratio of the cross section of the gaps 32, the surface condition of the protective member 30, and the like. It can depend on the elements.

In the present embodiment, the spacing of the voids 32 is, for example, 50 μm or more and 600 μm or less, preferably 100 μm or more and 300 μm or less. By setting the interval of the gaps 32 to 50 μm or more, it is possible to suppress the occurrence of capillary action when the ozonated water is supplied, and to suppress the ozonated water from entering the gaps 32 due to the capillary action. Furthermore, by setting the interval of the voids 32 to 100 μm or more, it is possible to stably suppress the occurrence of capillary action. On the other hand, by setting the interval of the voids 32 to 600 μm or less, at least one of the surface tension of the ozonized water generated within the voids 32 and the repulsive force of the air trapped within the voids 32 is ensured when the ozonized water is supplied. be able to. Furthermore, by setting the interval of the air gap 32 to 300 μm or less, at least one of the surface tension and the repulsive force of air can be stably secured. From the viewpoint of mounting accuracy, the interval of the gap 32 is preferably 50 μm or more, for example. Moreover, from the viewpoint of trapping air in the gap 32 , it is preferable that at least one side constituting the side wall surface of the opening 31 is spaced apart from the side surfaces of the electrodes 21 , 22 , 23 .

The aspect ratio of the height of the gaps 32 to the interval of the gaps 32 is preferably 1 or more, for example. Specifically, for example, when the height of the gap 32 is 380 μm, the interval of the gap 32 is preferably 0 to 380 μm, more preferably 100 μm (aspect ratio 3.8). Alternatively, for example, when the height of the gap 32 is 200 μm, the interval of the gap 32 is preferably 0 or more and 200 μm or less, more preferably 80 μm (aspect ratio 2.5).

The surface condition of the protection member 30 is preferably water repellent. Specifically, it is preferable that the contact angle of water of the material forming the protective member 30 is, for example, 60° or more. With such a configuration, it is possible to stably suppress the entry of ozone water into the space 32 .

The gap 32 is preferably formed over the entire circumference of the outer edges of the electrodes 21, 22, and 23, but is not necessarily limited to this. It is sufficient if it is formed in the part. When formed at least partially, the inner wall surfaces of the openings 31 may be in contact with the side surfaces of the electrodes 21, 22, and 23, or other members (for example, insulating member) may be filled.

(Relationship between sensor electrode and protection member)
When the protective member 30 is arranged so as to surround the electrodes 21, 22, and 23, the surface 30a of the protective member 30 facing the support substrate 10, excluding the opening 31, covers the electrodes 21, 22, and 23. 23, a flush structure is formed with respect to the detection surface 20a.

Here, the “flush structure” mainly refers to a structure in which the detection surfaces 20a of the electrodes 21, 22, and 23 and the surface 30a of the protective member 30 have the same height from the upper surface of the support substrate 10. , and further includes structures that can be regarded as identical. The phrase "can be regarded as being identical" means that even if there is a step, the size of the step is equal to or less than a predetermined allowable value. As for the allowable size of the step, for example, when the distance between the electrodes 21, 22, and 23 is defined as the distance a, and the allowable maximum step is the size b, the size b is preferably the distance a. 1/5 or less, more preferably 1/10 or less.

In addition to the structure in which the detection surface 20a of each electrode 21, 22, 23 and the surface 30a of the protective member 30 are parallel, the "flush structure" also includes a structure that can be regarded as being parallel. "Considered to be parallel" means that each surface is not completely parallel, and even if there is a non-parallel inclination, the magnitude of the inclination is below the allowable value. As for the magnitude of the tilt that can be tolerated, for example, when the vertical distance generated by the tilt is defined as the distance c, the distance c is preferably 1/5 or less, more preferably 1/10 or less of the above distance a. It is conceivable that

With such a flush structure, the detection surfaces 20a of the electrodes 21, 22, and 23 and the surface 30a of the protection member 30 arranged to surround them form the same plane, Or it can be regarded as constituting the same plane. That is, the surface 30a of the protective member 30 has the same height (including heights that can be regarded as the same) as the detection surfaces 20a of the electrodes 21, 22, and 23 with the upper surface of the support substrate 10 as a reference. It will be.

Thus, if the detection surface 20a of each electrode 21, 22, 23 and the surface 30a of the protective member 30 form a flush structure, there is a step (uneven structure) between the detection surface 20a and the surface 30a. ) does not occur. Therefore, when the ozone reaches the electrodes 21, 22, and 23 by diffusion during the measurement of the ozone concentration in the ozone water in a stationary state, there is no obstacle that hinders the diffusion of the ozone. , 22 and 23 are uniformly and continuously diffused.

Moreover, since the gaps 32 are formed between the openings 31 of the protective member 30 and the electrodes 21, 22, 23, which constitute the flush structure, the effect of suppressing the penetration of ozone water by the gaps 32 is maintained. be.

In other words, in the sensing area, even when the electrodes 21, 22, and 23 are arranged in the opening 31 of the protective member 30, the flush structure does not cause a step (uneven structure) over the entire area. In addition, since the effect of suppressing the permeation of ozone water by the gap 32 is maintained, the appropriate supply of ozone water to each of the electrodes 21, 22, and 23 can be ensured.

(2) Method for Manufacturing Electrochemical Sensor Next, a method for manufacturing the electrochemical sensor 1 according to this embodiment will be described.
FIG. 3 is a flowchart showing an example of the procedure of the method for manufacturing the electrochemical sensor 1 according to this embodiment.

As shown in FIG. 3, the method for manufacturing the electrochemical sensor 1 according to the present embodiment includes at least a preparation step (step 101, hereinafter the step is abbreviated as "S"), a bonding material placement step (S102), It includes a protective member joining step (S103) and a sensor electrode joining step (S104).

(Preparation step: S101)
In the preparation step (S101), components of the electrochemical sensor 1 are prepared. Specifically, a support substrate 10 having electrode pads 11, connection terminals 12 and wirings 13 formed on one main surface, and a plurality of chip electrodes 21, 22 and 23 to be arranged on the support substrate 10. , a conductive bonding material 26 for bonding the electrodes 21, 22, and 23, a protective member 30 formed with openings 31 corresponding to the electrodes 21, 22, and 23, and the protective member 30. and an insulating bonding material 33 for each are prepared.

Of these, the support substrate 10 can be manufactured using various known techniques such as resist coating, exposure, development, etching, and resist removal. The electrodes 21, 22, and 23 can also be manufactured using various known techniques such as film forming techniques such as CVD and PVD and processing techniques such as dicing.

The conductive bonding material 26 can be obtained, for example, by cutting a sheet-like adhesive tape whose base material is a conductive nonwoven fabric into a planar shape corresponding to the sensor electrode 20 and the electrode pad 11 . The protective member 30 can be obtained, for example, by molding a PET film having a predetermined thickness having insulating properties and water repellency into a planar shape having an opening 31 corresponding to the sensing area set on the support substrate 10. can be done. The insulating bonding material 33 can be obtained, for example, by cutting a sheet-like adhesive tape whose base material is an insulating PET film into a planar shape corresponding to the protective member 30 .

(Bonding material placement step: S102)
After the preparation step (S101) is completed, the bonding material placement step (S102) is performed. In the bonding material placement step (S102), the conductive bonding material 26 and the insulating bonding material 33 are placed.

The conductive bonding material 26 is arranged on the support substrate 10 by sticking it onto the electrode pads 11 of the support substrate 10 . At this time, if the planar size of the conductive bonding material 26 is larger than the planar size of the electrode pad 11, even if the positional control when arranging the conductive bonding material 26 is not strictly performed (positional deviation within the allowable tolerance can be prevented). ), the conductive bonding material 26 can cover the entire upper surface of the electrode pad 11 . That is, even if there is a positional deviation within the allowable tolerance, the overlapping area between the sensor electrode 20 and the electrode pad 11 is not lost. Therefore, it is very preferable to ensure electrical connection between the sensor electrode 20 and the electrode pad 11 . Moreover, since the entire upper surface of the electrode pad 11 is covered with the conductive bonding material 26, the sensor electrode 20 can be bonded onto the electrode pad 11 without tilting or the like in the sensor electrode bonding step (S104) described later. It is feasible and very favorable to ensure the air gap 32 around the sensor electrode 20 .

Moreover, the insulating bonding material 33 may be arranged on the support substrate 10 when the protective member 30 is bonded. Therefore, in consideration of ease of work, the insulating bonding material 33 is pasted on the protective member 30 side, not on the support substrate 10 . At this time, the opening formed in the insulating bonding material 33 is aligned with the position of the opening 31 of the protective member 30 . However, it is not limited to this, and the insulating bonding material 33 may be arranged on the support substrate 10 .

It does not matter which of the placement of the conductive bonding material 26 and the placement of the insulating bonding material 33 is performed first.

(Protective member bonding step: S103)
After the bonding material disposing step (S102) is completed, the protective member bonding step (S103) is performed. That is, the protective member bonding step (S103) is performed before the sensor electrode bonding step (S104).

In the protective member bonding step ( S<b>103 ), the protective member 30 is placed on the support substrate 10 and the support substrate 10 and the protective member 30 are bonded via the insulating bonding material 33 . The protection member 30 is arranged so that the electrode pads 11 and the conductive bonding material 26 on the support substrate 10 are positioned within the openings 31 formed in the protection member 30 .

However, the sensor electrode 20 (each of the electrodes 21, 22, 23) is not placed on the conductive bonding material 26 at this time. In this way, by performing the protective member bonding step (S103) before the sensor electrode bonding step (S104), for example, the arrangement of the protective member 30, the presence of the conductive bonding material 26 or the insulating bonding material 33, etc. Contamination of the detection surface 20a of the sensor electrode 20 caused by this can be suppressed. Further, for example, even when a thermosetting adhesive is used instead of an adhesive tape as the insulating bonding material 33, the sensor electrode 20 may be adversely affected by heat treatment for thermosetting. do not have.

In arranging the protective member 30 , the insulating bonding material 33 that is attached in advance to the protective member has a planar size of each opening in the insulating bonding material 33 . If it is larger than the size, even if positional control is not strictly performed when attaching the insulating bonding material 33 (even if there is a positional deviation within the allowable tolerance), the insulating property of the protective member 30 into the opening 31 can be reduced. Protrusion of the bonding material 33 can be suppressed. In other words, even if there is a positional deviation within the allowable tolerance, the insulating bonding material 33 will not protrude into the opening 31 . Therefore, it is possible to ensure the desired shape, capacity, etc. of the gap 32 and to prevent contamination of the sensor electrode 20 due to the protrusion of the insulating bonding material 33 .

Moreover, if the planar size of each opening in the insulating bonding material 33 is larger than the planar size of each opening 31 in the protective member 30, when the support substrate 10 and the protective member 30 are bonded via the insulating bonding material 33, In addition, a separation region 32b is formed between the bottom surface of the protective member 30 and the top surface of the support substrate 10. As shown in FIG. Spaced region 32 b communicates with gap 32 formed when sensor electrode 20 is arranged in opening 31 of protective member 30 . An air layer (air insulation layer) is formed in the spaced region 32b in the same manner as the gap 32. As shown in FIG. Therefore, when the spaced region 32b exists, as will be described in detail later, the effect of suppressing the infiltration of ozone water by the space 32 can be made more effective.

(Sensor electrode joining step: S104)
After the protective member bonding step (S103) is completed, the sensor electrode bonding step (S104) is performed to bond the sensor electrodes 20 (electrodes 21, 22, 23) onto the electrode pads 11 via the conductive bonding material 26. . The electrodes 21 , 22 , 23 are joined so that the electrodes 21 , 22 , 23 are positioned within the opening 31 of the protective member 30 and a gap 32 is formed between the electrodes 21 , 22 , 23 and the inner wall surface of the opening 31 . go to

As a result, each electrode 21 , 22 , 23 is electrically connected to the connection terminal 12 via the conductive bonding material 26 , the electrode pad 11 and the wiring 13 . Further, by bonding the electrodes 21, 22, 23, the detection surfaces 20a of the electrodes 21, 22, 23 and the surface 30a of the protective member 30 form a flush structure.

At this time, if the planar size of the conductive bonding material 26 is smaller than the planar size of the bottom surface of each of the electrodes 21, 22, 23, the positioning of the conductive bonding material 26 may not be strictly controlled (allowable tolerance Even if there is a positional deviation inside, the protrusion of the conductive bonding material 26 into the opening 31 of the protective member 30 can be suppressed. That is, even if there is a positional deviation within the allowable tolerance, the conductive bonding material 26 does not protrude into the opening 31 . Therefore, it is possible to ensure the desired shape, capacity, etc. of the gap 32 and to prevent the sensor electrode 20 from being contaminated due to the protrusion of the conductive bonding material 26 .
Furthermore, since the planar size of the conductive bonding material 26 is smaller than the planar size of the bottom surface of each electrode 21, 22, 23, the bottom surface of each electrode 21, 22, 23 and the top surface of the support substrate 10 are separated from each other. A region 32a is formed. The spaced region 32 a communicates with the gap 32 formed between each electrode 21 , 22 , 23 and the protective member 30 . An air layer (air insulating layer) is formed in the spaced region 32a in the same manner as the gap 32. As shown in FIG. Therefore, when the spaced region 32a exists, as will be described in detail later, the effect of suppressing the infiltration of ozone water by the space 32 can be made more effective.

The electrochemical sensor 1 is manufactured through at least the above steps (S101 to S104).

(3) Usage Mode of Electrochemical Sensor Next, a usage mode of the electrochemical sensor 1 according to the present embodiment will be described.

The electrochemical sensor 1 according to this embodiment is used by being connected to an electrochemical measurement device (hereinafter also simply referred to as "measurement device"). Furthermore, a computer device is connected to the measuring device. Note that the measuring device and the computer device may be configured as an integrated device.

The measuring device functions as, for example, a potentiostat, and through connection with the connection terminal 12 of the electrochemical sensor 1, controls the electrochemical reactions at the electrodes 21, 22, and 23 that come into contact with the ozone water. It measures potential and current. More specifically, the measurement device applies a voltage between the working electrode 21 and the counter electrode 22 by controlling the voltage applied to each of the electrodes 21, 22, and 23, and the potential of the reference electrode 23 is used as a reference for the working electrode. The potential of 21 is made sweepable, and the current flowing between the working electrode 21 and the counter electrode 22 in response to the electrochemical reaction occurring at the working electrode 21 is measured. That is, the measuring device performs electrochemical measurement by the three-electrode method using LSV. Details of the LSV can be obtained by using a known technique, and the explanation thereof is omitted here.

The computer device is configured to function as a control unit that controls processing operations in the measuring device by executing a predetermined program. The control performed by the computer includes at least control of the electrochemical measurement process, that is, control of the process of measuring the O ₃ concentration in the ozone water based on the measurement result of the current value by the measuring device. Note that the computer device is not limited to a stationary type represented by a personal computer device as long as it has an information processing function to execute a predetermined program, and may be a portable information terminal device represented by a smart phone. There may be.

When the _O3 concentration in the ozonated water is measured using the electrochemical sensor 1, the measuring device and the computer, the electrodes 21, 22 and 23 of the electrochemical sensor 1 are brought into contact with the ozonated water. Specifically, for example, at least the sensing region of the electrochemical sensor 1 is immersed in ozone water, thereby bringing the electrodes 21, 22, and 23 into contact with the ozone water. Even if the immersion in the ozone water is performed beyond the sensing region, since the insulating protective film 14 covers the wiring 13, there is no risk of leakage current or the like occurring.

At this time, it is preferable to secure a sufficient amount of ozone water, which is the test liquid, for the electrochemical sensor 1 . In addition, it is preferable that the ozonized water is kept in a stationary state without agitation, that is, in a state where the liquid does not flow, and the measurement is performed immediately after drawing the test liquid. This is because if a long time elapses after drawing the sample liquid, there is a possibility that the concentration cannot be measured accurately due to the influence of ozone being consumed over time.

When the electrodes 21, 22, and 23 come into contact with ozone water, the electrochemical sensor 1 according to the present embodiment has a structure in which the detection surfaces 20a of the electrodes 21, 22, and 23 and the surface 30a of the protective member 30 are flush with each other. Since it is configured, there is no step (uneven structure) between the detection surface 20a and the surface 30a.

Therefore, if the detection surface 20a of each of the electrodes 21, 22, 23 and the surface 30a of the protective member 30 form a flush structure, for example, when measuring the concentration of dissolved ozone in ozone water, a step (uneven structure) The presence of prevents the diffusion of the substance to be measured contained in the sample liquid. Therefore, the flush structure of the detection surfaces 20a of the electrodes 21, 22, and 23 and the surface 30a of the protective member 30 makes it possible to optimize the state of the electrodes 21, 22, and 23 after the ozone water is supplied. As a result, it is possible to sufficiently secure the reliability of concentration measurement of dissolved ozone in ozone water.

When the electrodes 21 , 22 , 23 are brought into contact with ozone water while utilizing such a flush structure, the electrodes 21 , 22 , 23 are positioned within the openings 31 of the protective member 30 . An air layer (air insulating layer) is formed by a gap 32 between the electrodes 21 , 22 , 23 and the protective member 30 . Therefore, when ozonized water is supplied to each of the electrodes 21, 22, and 23, the surface tension of the ozonized water generated within the gap 32 and the repulsive force of the air trapped within the gap 32 are Intrusion of ozonized water is suppressed by at least one of the above. As a result, the supplied ozonized water comes into contact with the detection surfaces 20a of the electrodes 21, 22, and 23, but does not contact portions other than the detection surfaces 20a (for example, side end surfaces of the electrodes 21, 22, and 23). no contact. That is, the electrodes 21, 22, and 23 are insulated from the air by the effect of suppressing the infiltration of the ozonized water by the gaps 32 at the side end surfaces and the like, which interfere with measurement due to the generation of leakage current when the ozonated water comes into contact. .

In particular, when the spaced regions 32a and 32b are formed so as to communicate with the gap 32, the effect of the gap 32 for suppressing the entry of ozone water becomes even more remarkable. The repulsive force of the air trapped within the void 32 can be caused by the lack of escape routes for the air within the void 32 . In this case, if the separation regions 32a and 32b exist on the far side of the gap 32 as viewed from the supply side of the ozonized water, the volume of trapped air increases, while the opening of the gap 32 becomes the separation region. Since it is narrower than the formation part of 32a, 32b, it becomes difficult for air to escape. Therefore, the effect of suppressing penetration of ozonized water is enhanced.

Moreover, the above-described air insulation due to the flush structure and ozone water infiltration suppression effect is realized by arranging the protective member 30 so as to surround the electrodes 21 , 22 , 23 . In other words, only by arranging the protective member 30 as a single component between the electrodes 21, 22, 23, a very simple structure can be achieved without complicating the configuration as in the case of resin-sealed insulation, for example. Depending on the configuration, it is possible to ensure the reliability of the electrochemical measurement performed by the electrochemical sensor 1 . Therefore, it is possible to easily reduce the cost of the electrochemical sensor 1 by simplifying the configuration, and it is very preferable to apply it to the electrochemical sensor 1 for disposable use, for example.

After the electrodes 21, 22, and 23 are brought into contact with the ozone water as described above, while maintaining this state, the measuring device controls the voltages applied to the electrodes 21, 22, and 23. , a voltage is applied between the working electrode 21 and the counter electrode 22, the potential of the working electrode 21 is swept based on the potential of the reference electrode 23, and the current value flowing between the working electrode 21 and the counter electrode 22 at that time to measure.

Then, after the measurement device measures the current value, the computer device performs necessary processing to specify the O ₃ concentration in the ozone water based on the measured value.

At this time, when at least the working electrode 21 and the counter electrode 22 are BDD electrodes, high detection sensitivity is obtained. In other words, it is possible to measure the O ₃ concentration in the ozone water while taking advantage of the characteristic of the BDD electrode that it has high detection sensitivity.

The electrochemical sensor 1 according to the present embodiment is used when measuring the O ₃ concentration in the ozone water by the procedure described above. After the O ₃ concentration in the ozone water is measured, the used electrochemical sensor 1 is removed from the measurement device and discarded if, for example, the electrochemical sensor 1 is disposable.

(4) Effect of this embodiment According to this embodiment, one or more of the following effects can be obtained.

(a) In the electrochemical sensor 1 of the present embodiment, the detection surfaces 20a of the electrodes 21, 22, and 23 and the surface 30a of the protective member 30 form a flush structure. A step (uneven structure) does not occur with the surface 30a. If there is a step (uneven structure) between the detection surface 20a and the surface 30a, when the electrodes 21, 22, and 23 come into contact with the ozone water, air bubbles adhere to the step and remain on the electrode 21. , 22 and 23 may not be completely covered with the ozone water, but this risk can be reduced by eliminating the step (uneven structure). Also, when the ozone concentration is measured, there are no obstacles that hinder the diffusion of ozone in the ozone water in the vicinity of the electrodes 21, 22, and 23 due to the elimination of the step (uneven structure). , 22 and 23 after the supply of the ozonized water can be optimized. As a result, high reliability, high sensitivity, etc. of electrochemical measurement can be achieved, and the reliability of concentration measurement of the substance to be measured in the sample liquid can be sufficiently ensured.

Furthermore, when the ozone water is supplied to each electrode 21, 22, 23, since the gap 32 is formed between each electrode 21, 22, 23 and the protective member 30, the penetration of the ozone water through the gap 32 is prevented. An inhibitory effect is obtained. Therefore, portions of the electrodes 21, 22, and 23 other than the detection surface 20a (for example, the side end surfaces of the electrodes 21, 22, and 23) are insulated from air, and leakage currents at portions other than the detection surface 20a are insulated. The generation can be suppressed, and as a result, it becomes possible to suppress the decrease in measurement accuracy (sensitivity, S/N ratio) in measuring the O ₃ concentration in the ozonated water. In other words, it can be said that the supply of ozone water to each of the electrodes 21, 22, and 23 can be made appropriate also in this respect.

Moreover, the above-described air insulation due to the flush structure and ozone water infiltration suppression effect is realized by arranging the protective member 30 so as to surround the electrodes 21 , 22 , 23 . In other words, only by arranging the protective member 30 as a single component between the electrodes 21, 22, 23, a very simple structure can be achieved without complicating the configuration as in the case of resin-sealed insulation, for example. Depending on the configuration, it is possible to ensure the reliability of the electrochemical measurement performed by the electrochemical sensor 1 . Therefore, it is possible to easily reduce the cost of the electrochemical sensor 1 by simplifying the configuration, and it is very preferable to apply it to the electrochemical sensor 1 for disposable use, for example.

(b) In this embodiment, the protective member 30 covers the entire sensing area. Therefore, at least in the sensing area, the flush structure prevents the generation of a step (uneven structure) over the entire area, and the effect of suppressing the penetration of ozone water by the gap 32 is maintained. Appropriate water supply can be ensured.

(c) In the present embodiment, the opening 31 in the protective member 30 is at least partially spaced apart from the electrodes 21, 22, and 23 positioned in the opening 31 by a predetermined gap. 32, excessive contamination of each electrode 21, 22, 23 can be suppressed. For example, in the case of insulating the electrodes 21, 22, and 23 by covering the portions other than the detection surface 20a with an insulating resin, contamination due to the insulating resin itself and contamination due to organic matter volatilized by heat during curing of the resin may occur. However, there is no such possibility in this embodiment. As described above, in the present embodiment, the presence of the gap 32 suppresses excessive contact between the protection member 30 and the electrodes 21, 22, and 23, thereby preventing the electrodes 21 from forming or installing the protection member 30. , 22 and 23 can be suppressed.

(d) In the present embodiment, the gap 32 is formed so as to prevent the ozone water from entering the gap 32 . That is, the size, aspect ratio, etc. of the gap 32 are set so as to obtain the effect of suppressing the permeation of ozone water. Therefore, with a very simple configuration in which the air gap 32 is provided, it is possible to insulate portions of the electrodes 21, 22, and 23 other than the detection surface 20a from the air. , which is very preferable in terms of suppressing deterioration in measurement accuracy (sensitivity, S/N ratio) of O ₃ concentration in ozonated water. That is, with a very simple configuration, it is possible to ensure reliability when electrochemical measurement is performed by the electrochemical sensor 1 .

(e) In the present embodiment, when the separation regions 32a and 32b are formed so as to communicate with the gap 32, the effect of the gap 32 for suppressing the penetration of ozone water becomes even more remarkable. In other words, if the separation regions 32a and 32b exist on the far side of the gap 32 as viewed from the supply side of the ozonized water, the volume of air trapped thereby increases, while the opening of the gap 32 becomes the separation regions 32a and 32b. Since it is narrower than the formation portion of 32b, it becomes difficult for air to escape, and as a result, the effect of suppressing the infiltration of ozonized water is enhanced. By enhancing the effect of suppressing the permeation of ozonated water in this manner, the appropriate supply of ozonized water to each of the electrodes 21, 22, and 23 becomes even more reliable.
Moreover, when the spaced regions 32a and 32b exist, it is possible to prevent the conductive bonding material 26 or the insulating bonding material 33 from protruding into the opening 31. Therefore, the shape and capacity of the gap 32 can be adjusted as desired. In addition, contamination of the sensor electrode 20 due to the protrusion of the conductive bonding material 26 or the insulating bonding material 33 can be prevented.

(f) In the present embodiment, when a BDD electrode is used as the sensor electrode 20, the sensor electrode 20 has a conductive substrate 25 and an electrode film 24 forming the detection surface 20a. will be formed by polycrystalline diamond or DLC. Therefore, the sensor electrode 20 has high detection sensitivity and is suitable for improving the measurement accuracy of the O ₃ concentration in the ozone water.

(g) In this embodiment, the sensor electrode 20 consists of three electrodes, a working electrode 21, a counter electrode 22 and a reference electrode 23, of which at least the working electrode 21 and the counter electrode 22 are BDD electrodes. Therefore, the working electrode 21 and the counter electrode 22, which are electrodes that contribute to current measurement using LSV, are both composed of BDD electrodes with high detection sensitivity, and the measurement accuracy of O ₃ concentration in ozone water is It is suitable for improving

(h) In this embodiment, the sensor electrode 20 is bonded onto the electrode pad 11 via a conductive bonding material 26 made of a conductive adhesive sheet or conductive adhesive. Therefore, it is possible to easily and reliably bond the sensor electrode 20 onto the electrode pad 11 . Moreover, the conduction between the sensor electrode 20 and the electrode pad 11 is ensured without requiring a bonding wire or the like for bonding onto the electrode pad 11 . Therefore, it is very preferable to simplify the configuration of the electrochemical sensor 1 . Furthermore, since the conductive bonding material 26 is bonded to the bottom surface (conductive substrate side) of the sensor electrode 20, the entire surface (polycrystalline diamond film side) of the sensor electrode 20 can be used for electrochemical measurement. , is also obtained.

(i) In the present embodiment, the electrical resistivity of the conductive bonding material 26 interposed between the sensor electrode 20 and the electrode pad 11 is, for example, 0.1 kΩ·m or less. Such an electrical resistivity is very preferable for ensuring conduction between the sensor electrode 20 and the electrode pad 11 even when they are joined via the conductive joining material 26 .

(j) In the present embodiment, the planar size of the conductive bonding material 26 interposed between the sensor electrode 20 and the electrode pad 11 is larger than the planar size of the top surface of the electrode pad 11 and the planar size of the bottom surface of the sensor electrode 20. less than With such a planar size, the overlapping area between the sensor electrode 20 and the electrode pad 11 is lost even if the position is not strictly controlled during arrangement (even if the position is misaligned within the allowable tolerance). Therefore, it is very preferable to secure electrical connection between the sensor electrode 20 and the electrode pad 11 . Moreover, when the sensor electrode 20 is bonded onto the electrode pad 11, the protrusion of the conductive bonding material 26 into the opening 31 can be suppressed. contamination can be prevented. Furthermore, since the separation region 32a communicating with the gap 32 is formed between the bottom surface of the sensor electrode 20 and the upper surface of the support substrate 10, the effect of suppressing the penetration of ozone water by the gap 32 is even more effective. can be

(k) In the present embodiment, the conductive bonding material 26 interposed between the sensor electrode 20 and the electrode pad 11 is composed of a material that does not contain an organic component that is volatile at room temperature and has a molecular weight of 100 or more. ing. Therefore, there is no risk of contamination of the sensor electrode 20 by the organic matter volatilized from the conductive bonding material 26, which is very preferable in terms of suppressing contamination of the sensor electrode 20. FIG.

(l) In the present embodiment, the protective member 30 is made of a water-repellent material. Therefore, the surface tension of the ozonated water generated in the gap 32 can be increased, and as a result, it is possible to stably suppress the intrusion of the ozonated water into the gap 32 .

(m) In this embodiment, the protective member 30 is bonded onto the support substrate 10 via an insulating bonding material 33 made of an insulating adhesive sheet or an insulating adhesive. Therefore, it is possible to easily and reliably bond the protective member 30 onto the support substrate 10 . Moreover, since the insulating bonding material 33 also has insulating properties like the protective member 30, there is no concern about leakage current or the like.

(n) In the present embodiment, the planar size of the opening in the insulating bonding material 33 interposed between the protective member 30 and the support substrate 10 is larger than the planar size of the opening 31 in the protective member 30 . With such a planar size, it is possible to prevent the insulating bonding material 33 from protruding into the opening 31 when bonding the protective member 30 onto the support substrate 10 . Contamination of the sensor electrode 20 due to the protrusion can be prevented. Furthermore, since the separation region 32b communicating with the gap 32 is formed between the bottom surface of the protective member 30 and the upper surface of the support substrate 10, the effect of suppressing the invasion of ozone water by the gap 32 is even more effective. can be

(o) In the present embodiment, the insulating bonding material 33 interposed between the protective member 30 and the support substrate 10 is composed of a material that does not contain an organic component that is volatile at room temperature and has a molecular weight of 100 or more. ing. Therefore, there is no fear of contamination of the sensor electrode 20 by the organic substance volatilized from the insulating bonding material 33, which is very preferable in terms of suppressing contamination of the sensor electrode 20. FIG.

(p) In the present embodiment, since the support substrate 10 is flexible, for example, even if an excessive load occurs during use of the electrochemical sensor 1, the support substrate 10 may be bent and damaged. Therefore, it is possible to prevent a situation in which continuous measurement of the O ₃ concentration in the ozonized water becomes difficult. Further, for example, after use of the electrochemical sensor 1, it becomes possible to dispose of the electrochemical sensor 1 with the support substrate 10 folded, thereby improving convenience for the user.

(q) In this embodiment, the wiring 13 on the support substrate 10 is covered with the insulating protective film 14 . Therefore, even if the electrochemical sensor 1 is immersed in the ozone water beyond the sensing region of the electrochemical sensor 1, the insulating protective film 14 covers the wiring 13, so that a leakage current or the like is generated. There is no risk of it happening.

(r) In the present embodiment, the specific component whose concentration is to be measured using the electrochemical sensor 1 is dissolved ozone in ozone water, which is the test liquid. That is, the electrochemical sensor 1 according to the present embodiment is suitable for use in measuring the _O3 concentration in ozone water, and it becomes possible to ensure the reliability of the _O3 concentration measurement.

(s) In the present embodiment, when manufacturing the electrochemical sensor 1, the protective member bonding step (S103) is performed prior to the sensor electrode bonding step (S104). Therefore, contamination of the detection surface 20a of the sensor electrode 20 due to, for example, the arrangement of the protective member 30 and the presence of the conductive bonding material 26 or the insulating bonding material 33 can be suppressed. Further, for example, even when a thermosetting adhesive is used instead of an adhesive tape as the insulating bonding material 33, the sensor electrode 20 may be adversely affected by heat treatment for thermosetting. do not have.

(5) Modifications, etc. As described above, the present embodiment has been described, but the technical scope of the present disclosure is not limited to the content of the above-described embodiment, and can be variously changed without departing from the gist thereof. .

(concentration measurement)
In the above-described embodiment, the case where LSV measurement is performed when measuring the _O3 concentration in ozone water is taken as an example, but the present invention is not necessarily limited to this, and cyclic voltammetry (CV) measurement is used. Alternatively, chronoamperometry (CA) measurement may be used.

Further, for example, in the above-described embodiment, the sample liquid is ozonated water, and the specific component whose concentration is to be measured is dissolved ozone in the ozonated water. Instead, it is applicable to other types of test liquids and specific components as long as the concentration can be measured using an electrochemical reaction.

When applying to other types of test liquids and specific components, the supply of the test liquid to the sensor electrode 20 may be performed in a manner different from the above embodiment. In the above-described embodiment, the case where the sensing region of the electrochemical sensor 1 is immersed in ozone water in a stationary state was exemplified. is a specific component to be measured, the sample liquid may be supplied to the sensor electrode 20 by pouring urine, which is the sample liquid, over the sensing region. Even in that case, if there is no step (uneven structure) due to the flush structure, the supplied sample liquid will not be discontinuous due to the step (for example, the working electrode surface droplets supplied to the sensor electrode 20 and droplets supplied to other electrode surfaces are not interrupted by the uneven structure), and the supply of the test liquid to the sensor electrode 20 is performed uniformly and continuously. Therefore, it is possible to appropriately supply the sample liquid to the sensor electrode 20 .

(Sensor electrode)
In the above-described embodiment, the case where the sensor electrode 20 consists of the working electrode 21, the counter electrode 22, and the reference electrode 23 was taken as an example, but it is not necessarily limited to this. For example, it can be applied in the same manner as in the case of the triode, even in the case of a working electrode and a counter electrode, or in the case where four or more sensor electrodes are arranged.

This means that the number of sensor electrodes is not particularly limited in the present disclosure, and the following technical ideas are also included, including the case of a single sensor electrode.
In one aspect of the present disclosure,
An electrochemical sensor used to measure the concentration of a specific component in a test solution,
a protective member having an opening;
a sensor electrode disposed within the opening;
a support member that supports the protection member and the sensor electrode,
With the support member supporting the protection member and the sensor electrode, the detection surface of the sensor electrode on the side facing the support substrate and the side of the protection member facing the support substrate excluding the opening. and the surface of the electrochemical sensor form a flush structure.

In the above-described embodiment, the case where the sensor electrode 20 is the BDD electrode is taken as an example, but the present invention is not necessarily limited to this, and other types of sensor electrodes can be applied in exactly the same way. It is possible. However, as described in the above embodiment, at least the working electrode 21 and the counter electrode 22 are preferably BDD electrodes, and the reference electrode 23 is either a BDD electrode or a metal electrode (Ag electrode, etc.). be able to. Further, the working electrode 21 may function as a modified electrode (modified sensor) in which a predetermined metal or the like as a molecular receptor is attached to the surface of the electrode film 24 of the BDD electrode.

Furthermore, the arrangement of the sensor electrodes 20 on the support substrate 10 is not limited to the aspects described in the above-described embodiments, and can be changed as necessary. The change referred to here includes the replacement of the functions of the working electrode 21 , the counter electrode 22 and the reference electrode 23 .

(others)
Each component of the electrochemical sensor 1 described in the above-described embodiment is merely an example, and may be changed as appropriate within a range that does not impair its function, action, and the like.
For example, the conductive bonding material 26 or the insulating bonding material 33 may be a paste adhesive instead of an adhesive sheet.
Further, for example, the protection member 30 has been described as being made of a water-repellent material, but the surface of the protection member 30 may be made water-repellent by applying a surface treatment.

In the above-described embodiment, the method for manufacturing the electrochemical sensor 1 includes the preparation step (S101), the bonding material placement step (S102), the protective member bonding step (S103), and the sensor electrode bonding step (S104). Although the case of implementing in this order has been described, the present disclosure is not limited to this case. In the manufacturing method of the electrochemical sensor 1, the order of the steps after the preparation step (S101) may be changed as appropriate.

(6) Preferred Embodiments of the Present Disclosure Preferred embodiments of the present disclosure are additionally described below.

(Appendix 1)
According to one aspect of the present disclosure,
a protective member having a plurality of openings;
a plurality of sensor electrodes individually arranged in the plurality of openings;
a support member that supports the protective member and the plurality of sensor electrodes,
With the support member supporting the protection member and the plurality of sensor electrodes, the detection surface of the plurality of sensor electrodes on the side facing the support substrate and the plurality of openings of the protection member An electrochemical sensor is provided in which the surface facing the support substrate forms a flush structure.

(Appendix 2)
Preferably,
The electrochemical sensor according to Appendix 1 is provided, wherein the protective member is configured to cover the entire sensing region set on the support substrate.

(Appendix 3)
Preferably,
The opening in the protective member is formed so as to have a gap spaced at a predetermined distance from at least a portion of the opening and the sensor electrode positioned in the opening. is provided.

(Appendix 4)
Preferably,
The electrochemical sensor according to appendix 3 is provided, wherein the gap is formed so as to suppress intrusion of the test liquid into the gap when the test liquid is supplied to the sensor electrode. be done.

(Appendix 5)
Preferably,
The electrochemical sensor according to appendix 4, wherein a spaced region communicating with the gap is formed between the bottom surface of the sensor electrode and the top surface of the support substrate.

(Appendix 6)
Preferably,
The electrochemical sensor according to appendix 4 is provided, wherein a spaced region communicating with the gap is formed between the bottom surface of the protective member and the top surface of the support substrate.

(Appendix 7)
Preferably,
The sensor electrode has a conductive substrate and an electrode film provided on the conductive substrate and forming the detection surface,
The electrochemical sensor according to appendix 1 is provided, wherein the electrode film is made of polycrystalline diamond or diamond-like carbon.

(Appendix 8)
Preferably,
the plurality of sensor electrodes are composed of three electrodes of a working electrode, a counter electrode, and a reference electrode;
The electrochemical sensor according to appendix 7 is provided, wherein at least the working electrode and the counter electrode are boron-doped diamond electrodes in which the electrode film is formed of polycrystalline diamond or diamond-like carbon.

(Appendix 9)
Preferably,
9. The electrochemistry according to appendix 1 or 8, wherein the sensor electrode is bonded to an electrode pad formed on the support substrate via a conductive bonding material composed of a conductive adhesive sheet or adhesive. A sensor is provided.

(Appendix 10)
Preferably,
The electrochemical sensor according to appendix 9 is provided, wherein the electrical resistivity of the conductive bonding material is 0.1 kΩ·m or less.

(Appendix 11)
Preferably,
The electrochemical sensor according to appendix 9 is provided, wherein the planar size of the conductive bonding material is larger than the planar size of the top surface of the electrode pad and smaller than the planar size of the bottom surface of the sensor electrode.

(Appendix 12)
Preferably,
The electrochemical sensor according to appendix 9 is provided, wherein the conductive bonding material does not contain an organic component having a molecular weight of 100 or more, which is volatile at room temperature.

(Appendix 13)
Preferably,
The electrochemical sensor according to appendix 1 is provided, wherein the protective member is made of a material having water repellency.

(Appendix 14)
Preferably,
14. The electrochemical sensor according to Appendix 1 or 13, wherein the protective member is bonded to the support substrate via an insulating bonding material composed of an insulating adhesive sheet or adhesive.

(Appendix 15)
Preferably,
A plurality of openings are also formed in the insulating bonding material so as to correspond to the plurality of openings in the protective member,
15. The electrochemical sensor according to Appendix 14, wherein the planar size of the opening in the insulating bonding material is larger than the planar size of the opening in the protective member.

(Appendix 16)
Preferably,
The electrochemical sensor according to appendix 14 is provided, wherein the insulating bonding material does not contain an organic component that is volatile at room temperature and has a molecular weight of 100 or more.

(Appendix 17)
Preferably,
There is provided an electrochemical sensor according to Appendix 1, wherein the support substrate is configured to be flexible.

(Appendix 18)
Preferably,
Electrical wiring assigned to each of the plurality of sensor electrodes and connection terminals individually connected to the electrical wiring are provided on the support substrate,
The electrochemical sensor according to Supplementary Note 1 is provided, wherein the electrical wiring is covered with an insulating protective film except for the arrangement area of the protective member and the arrangement area of the connection terminals.

(Appendix 19)
Preferably,
The electrochemical sensor according to Appendix 1 or 7 is provided, wherein the specific component is dissolved ozone in the test liquid.

(Appendix 20)
According to another aspect of the present disclosure,
An electrochemical sensor used to measure the concentration of a specific component in a test solution,
a protective member having an opening;
a sensor electrode disposed within the opening;
a support member that supports the protection member and the sensor electrode,
With the support member supporting the protection member and the sensor electrode, the detection surface of the sensor electrode on the side facing the support substrate and the side of the protection member facing the support substrate excluding the opening. An electrochemical sensor is provided in which the surfaces of the are forming a flush structure.

(Appendix 21)
According to yet another aspect of the present disclosure,
A method for manufacturing an electrochemical sensor according to Appendix 1 or 20,
a protection member bonding step of bonding the support substrate and the protection member;
a sensor electrode bonding step of arranging the sensor electrode so as to be positioned within the opening of the protective member;
has at least
A method for manufacturing an electrochemical sensor is provided, wherein the protective member bonding step is performed prior to the sensor electrode bonding step.

DESCRIPTION OF SYMBOLS 1... Electrochemical sensor, 10... Support substrate, 11... Electrode pad, 12... Connection terminal, 13... Wiring (electric wiring), 14... Insulating protective film, 20... Sensor electrode, 20a... Detection surface, 21... Working electrode, 22 Counter electrode 23 Reference electrode 24 Electrode film 25 Conductive substrate 26 Conductive bonding material 30 Protective member 30a Surface 31 Opening 32 Gap 32a, 32b Spacing region, 33... Insulating bonding material

Claims (8)

An electrochemical sensor used to measure the concentration of a specific component in a test solution,
a protective member having a plurality of openings;
a plurality of sensor electrodes individually arranged in the plurality of openings;
a support member that supports the protective member and the plurality of sensor electrodes,
With the support member supporting the protection member and the plurality of sensor electrodes, the detection surface of the plurality of sensor electrodes on the side facing the support member and the plurality of openings of the protection member The surface on the side opposite to the support member constitutes a flush structure ,
The opening in the protective member is formed to have a gap spaced at a predetermined distance from at least a portion of the opening and the sensor electrode positioned in the opening.
Electrochemical sensor. The electrochemical sensor according to claim 1, wherein the protection member is configured to cover the entire sensing area set on the support member . The electrochemistry according to claim 1 or 2 , wherein the gap is formed so as to suppress the penetration of the test liquid into the gap when the test liquid is supplied to the sensor electrode. sensor. 4. The electrochemical sensor according to claim 3 , wherein a spaced region communicating with the gap is formed between the bottom surface of the sensor electrode and the top surface of the support member . 4. The electrochemical sensor according to claim 3 , wherein a spaced region communicating with the gap is formed between the bottom surface of the protection member and the top surface of the support member . The sensor electrode has a conductive substrate and an electrode film provided on the conductive substrate and forming the detection surface,
The electrochemical sensor according to claim 1, wherein the electrode film is made of polycrystalline diamond or diamond-like carbon. The electrochemical sensor according to claim 1 or 6 , wherein the specific component is dissolved ozone in the test liquid. A method for manufacturing the electrochemical sensor according to claim 1 ,
a protection member joining step of joining the support member and the protection member;
a sensor electrode bonding step of arranging the sensor electrode so as to be positioned within the opening of the protective member;
has at least
A method of manufacturing an electrochemical sensor, wherein the protective member bonding step is performed before the sensor electrode bonding step.

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