Method for manufacturing a sensor element, sensor element, and odor measuring device

Abstract

To stably manufacture a plurality of sensor elements for highly accurately measuring a smell substance contained in gas.SOLUTION: A manufacturing method for a plurality of sensor elements includes a slurry preparation step of preparing a plurality of kinds of slurries having different mixing ratios of a conductive carbon material, a resin composition and a surface active agent, an electrode arrangement step of arranging an electrode on a substrate, a region regulation step of regulating a coating region (330) where each of the plurality of kinds of slurries are coated, a coating step of coating each of the plurality of kinds of slurries to the coating region (330), and a drying step of drying the slurries and forming a smell substance receiving layer, wherein the area of the coating region is 0.0003 square centimeter or more and 0.2 square centimeter or less.SELECTED DRAWING: Figure 21

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing a sensor element, a sensor element, and an odor measuring device. [Background technology]

[0002] With the recent advancements in information processing technology, it is expected that if the sense of smell, one of the five human senses that has not been adequately measured mechanically, can be quantified in some way, it will be useful in a wide range of industrial fields. For example, in the medical field, it could be used for nursing care and assistance, preventive diagnosis and disease testing; in the environmental field, for odor management in factories, and for fermentation process management and wastewater treatment management in biogas utilization; in the safety field, for early detection of signs of landslides and floods, and for detecting deterioration of engine oil and machine oil. Furthermore, in the food industry, it could be used for detecting the maturation state of ingredients such as plants and meat, for process management of fermented foods such as alcoholic beverages, for plant cultivation management and quality control in the production, storage, and distribution processes of food; and in the marketing field, for cosmetics, body odor, fragrance environment, and fragrance production of products. To date, highly accurate and sensitive measurements of specific gaseous substances (gases) have been achieved using semiconductor gas sensors. Sensors with different response characteristics to various odors have been reported, and the composition of receptors contained in sensors is also being investigated.

[0003] The invention described in Patent Document 1 proposes a mechanism for detecting the adsorption of odor components onto the surface of a conductive polymer by replacing the semiconductor in a semiconductor gas sensor with a conductive polymer. Patent Document 1 reports that it is possible to detect odor components that are easily decomposed by heat and substances that do not undergo oxidation-reduction reactions on the surface of the sensor's detection part.

[0004] Furthermore, Patent Document 2 focuses on the property that the electrical resistance of a mixture of organic polymers and conductive materials changes when exposed to organic gases. Patent Document 2 describes that when multiple combinations of organic polymers / conductive materials with different organic polymer compositions are prepared and used as an electrical resistance array in a sensor, the change in electrical resistance when exposed to the same organic gas is different for each. Patent Document 2 reports that by utilizing this, odors can be identified by assigning the pattern of change in electrical resistance to the type of odor (= mixture of organic gases).

[0005] Furthermore, Patent Document 3 reports that adding a plasticizer to the above-mentioned organic polymer improves the response speed of the sensor.

[0006] Patent Document 4 reports an example of a gas detection device, specifically an alcohol detection device used in vehicles. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 11-23508 [Patent Document 2] Special Publication No. 11-503231 [Patent Document 3] Special Publication No. 2002-519633 [Patent Document 4] Japanese Patent Publication No. 2012-18021 [Overview of the project] [Problems that the invention aims to solve]

[0008] From the perspective of improving the accuracy and stability of odor measurement, there is room for improvement in the manufacturing method of the sensor element for measuring odor substances contained in a gas, the sensor element itself, and the odor measuring device.

[0009] Specifically, with sensor elements manufactured using previously known methods, when measuring the same odorous substance using sensor elements from different lots, the signal was inherently variable for each lot of sensor element. Therefore, when measurements were taken after switching sensor elements, it was difficult to determine whether the resulting change in the signal pattern was due to a change in the odor's chemical composition or to variability due to different lot numbers of sensor elements, making it difficult to accurately measure odors.

[0010] One aspect of the present invention aims to provide a sensor element for measuring odor substances contained in a gas with high precision, a method for manufacturing the same, and an odor measuring device equipped with the sensor element. [Means for solving the problem]

[0011] To solve the above problems, a method for manufacturing a plurality of sensor elements according to one aspect of the present invention includes a slurry preparation step of preparing a plurality of types of slurries comprising a conductive carbon material, a resin composition, and a surfactant, wherein the mixing ratios of the conductive carbon material, the resin composition, and the surfactant are different; an electrode placement step of arranging electrodes on a substrate; a region defining step of defining a coating region on the substrate on which the electrodes are arranged, to which each of the plurality of types of slurries is applied; a coating step of applying each of the plurality of types of slurries to the coating region; and a drying step of drying the slurry applied to the coating region to form an odor substance receiving layer, wherein the area of ​​the coating region is 0.0003 square centimeters or more and 0.2 square centimeters or less.

[0012] In order to solve the above problem, a sensor element according to one aspect of the present invention comprises an electrode disposed on a substrate, and an odorant-receiving layer formed on said electrode, wherein said odorant-receiving layer contains a conductive carbon material and a resin composition, and the sensor element is formed by applying each of a plurality of types of slurries with different mixing ratios of said conductive carbon material and said resin composition onto the substrate on which said electrode is disposed, in an application region where each of said plurality of types of slurries is applied, and then drying the applied plurality of types of slurries, and the area of said application region is not less than 0.0003 square centimeters and not more than 0.2 square centimeters. Effects of the Invention

[0013] According to one aspect of the present invention, there can be provided a sensor element for measuring odorants contained in gas with high accuracy, a method for manufacturing the same, and an odor measuring device comprising the sensor element. Brief Description of Drawings

[0014] [Figure 1] It is a schematic diagram showing an example of the configuration of an odor measuring device according to an embodiment of the present invention. [Figure 2] It is a top view showing an example of the configuration of a sensor element. [Figure 3] It is a cross-sectional view showing an example of the configuration of the sensor element shown in Fig. 2. [Figure 4] It is a schematic diagram showing an example of the configuration of an odor measuring device according to an embodiment of the present invention. [Figure 5] It is a top view showing a configuration example of a sensor chamber. [Figure 6] It is a cross-sectional view showing a configuration example of a sensor chamber. [Figure 7] It is a cross-sectional view showing a configuration example of a sensor chamber. [Figure 8] It is a functional block diagram showing an example of the configuration of an odor measuring device. [Figure 9] It is a flowchart showing an example of the flow of processing for generating an estimation model by an estimation device. [Figure 10]This is a functional block diagram showing an example of the configuration of an odor measuring device. [Figure 11] This flowchart shows an example of the process flow by which the estimation device estimates odor molecules. [Figure 12] This is a top view showing an example of the configuration of the sensor element of the present invention. [Figure 13] This is a top view showing an example of the configuration of the sensor element of the present invention. [Figure 14] This is a perspective view showing an example of the configuration of the sensor element of the present invention. [Figure 15] This is a top view showing an example of the configuration of the sensor element of the present invention. [Figure 16] This is a top view showing an example of the configuration of the sensor element of the present invention. [Figure 17] This is a top view showing an example of the configuration of the sensor element of the present invention. [Figure 18] This is a top view showing an example of the configuration of the sensor element of the present invention. [Figure 19] This is a top view showing an example of the configuration of the sensor element of the present invention. [Figure 20] This is a top view showing an example of the configuration of the sensor element of the present invention. [Figure 21] This is a flowchart illustrating an example of a method for manufacturing sensor elements. [Figure 22] This is a top view showing an example of a substrate before slurry coating. [Modes for carrying out the invention]

[0015] [Embodiment] One embodiment of the present invention is described below, but the present invention is not limited thereto. Unless otherwise specified in this specification, "A to B" representing a numerical range means "A or greater and B or less".

[0016] [1. Resin composition] A resin composition according to one embodiment of the present invention is a resin composition for forming an odor substance receiving layer, comprising a resin (A) and a conductive carbon material (C).

[0017] In this specification, "odor substance" broadly refers to a substance that can be adsorbed onto an odor substance receiving layer. Therefore, it includes substances that are not generally considered to be odor-causing substances. "Odor" often involves multiple odor substances, and there are also substances that are not recognized as odor substances or unknown odor substances. One embodiment of the present invention focuses on the fact that the amount of odor substance adsorbed onto the odor substance receiving layer differs depending on the type of odor substance.

[0018] In this specification, even when the term "odor substance" is used, it may refer not to an individual odor substance, but to a "collection of odor substances" that may contain multiple odor substances.

[0019] While not particularly limited, examples of "odor substances" include hexane, ethyl acetate, methanol, diethyl carbonate, toluene, d-limonene, bornan-2-one, cis-3-hexenol, β-phenylethyl alcohol, citral, L-carbone, γ-undecalactone, eugenol, linalyl acetate, menthol, benzaldehyde, vanillin, hexanal, ethanol, pentyl valerate, linalool, and 2-propanol.

[0020] Furthermore, in this specification, "odor substance receiving layer" means a layer that adsorbs odor substances to be identified. The odor substance receiving layer is formed from the resin composition described above. The odor substance receiving layer may be provided as part of a sensor element described later.

[0021] The sensor described in Reference 1 is thought to be capable of detecting odors consisting of individual compounds. However, many odors are mixtures of multiple substances. The sensor in Reference 1 lacks a function to distinguish odor components in its detection unit, and therefore its odor discrimination performance for mixtures is insufficient. Reference 2 shows that by utilizing the differences in the chemical structure of conductive polymers used in the detection unit, it is possible to recognize odors as mixtures by creating differences in the response of the detection unit to various compounds through each conductive polymer. However, the chemical structures of conductive polymers are limited, making it difficult to sensitively separate the response of the detection unit to any given odor component, and thus difficult to distinguish between odors consisting of similar components. Reference 3 proposes a method in which a mixture consisting of an organic polymer, a plasticizer, and a conductive substance is used as the detection material in the detection unit, and the penetration of odor components into the organic polymer is detected as a change in the electrical resistance of the mixture. By utilizing the fact that different odor components penetrate different organic polymer compositions, it is possible to recognize odors as mixtures by using an array in which multiple detection units consisting of the above detection material containing organic polymers of different compositions are used in parallel. However, with the above-mentioned organic polymers and organic polymers containing plasticizers, even if multiple combinations of organic polymers / conductive materials are prepared, the difference in chemical properties between the organic polymers is small, resulting in insufficient odor discrimination performance. These conventional technologies cannot accurately detect, for example, real odor patterns resulting from the interaction of multiple substances or real odor patterns from substances with unknown compositions.

[0022] The present inventors have focused on the fact that the electrical conductivity of the resin composition differs depending on the amount of odor substances adsorbed onto the resin composition, and that the adsorption process to the resin composition differs for each odor substance, and have invented a resin composition and sensor element, etc., according to one embodiment of the present invention. By using such a resin composition, the odor identification performance can be improved. For example, it is possible to identify real odor patterns resulting from the interaction of multiple substances or real odor patterns caused by substances of unknown composition.

[0023] <Resin (A)> The resin (A) contained in the resin composition according to one embodiment of the present invention is not particularly limited, but may be a urethane resin, polyalkylene oxide, acrylic resin, fluorine group-containing resin, vinyl polymer resin, silicone resin, polyamide resin, polyester resin, etc.

[0024] <Surfactant (B)> A resin composition according to one embodiment of the present invention may contain a surfactant (B) as described below. Surfactant (B) acts as a dispersant for the conductive carbon material (C) described later. Surfactant (B) can be appropriately selected from known surfactants within the range in which it exhibits the above-described effect.

[0025] Examples of surfactants (B) include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants.

[0026] Examples of anionic surfactants include alkali metal salts of carboxylic acids having 10 to 24 carbon atoms and alkali metal salts of alkyl sulfonic acids having 14 to 24 carbon atoms.

[0027] Examples of the carboxylic acids having 10 to 24 carbon atoms include decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, pentadecanoic acid, nonadecanoic acid, eicosanic acid, henicosanoic acid, docosanic acid, tricosanic acid, and tetracosanic acid.

[0028] Examples of alkyl groups in the C14-C24 alkylsulfonic acid include tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl, henicosyl, docosyl, tricosyl, and tetracosyl groups.

[0029] Examples of alkali metals included in the alkali metal salt include sodium and potassium.

[0030] Examples of cationic surfactants include quaternary ammonium halide salts having an alkyl group with 12 to 24 carbon atoms.

[0031] Examples of quaternary ammonium compounds having an alkyl group with 12 to 24 carbon atoms include tetrapropylammonium, tetrabutylammonium, tetrapentylammonium, tetrahexylammonium, dimethyldioctylammonium, didecyldimethylammonium, decyltrimethylammonium, dodecyltrimethylammonium, tridecyltrimethylammonium, hexadecyltrimethylammonium, methyltrioctylammonium, octyltrimethylammonium, tributylmethylammonium, octadecyltrimethylammonium, tetradecyltrimethylammonium, nonadecyltrimethylammonium, icosyltrimethylammonium, henicosyltrimethylammonium, heptadecyltrimethylammonium, and pentadecyltrimethylammonium.

[0032] Examples of the aforementioned halide salts include fluoride salts, chloride salts, bromide salts, and iodide salts.

[0033] Examples of amphoteric surfactants include dimethyl(3-sulfopropyl)ammonium intramolecular salt having an alkyl group with 10 to 22 carbon atoms, and N-alkyl-N,N-dimethylglycine having an alkyl group with 10 to 22 carbon atoms.

[0034] Examples of dimethyl(3-sulfopropyl)ammonium hydroxide intramolecular salts having an alkyl group with 10 to 22 carbon atoms include decyldimethyl(3-sulfopropyl)ammonium hydroxide intramolecular salt, undecyldimethyl(3-sulfopropyl)ammonium hydroxide intramolecular salt, dodecyldimethyl(3-sulfopropyl)ammonium hydroxide intramolecular salt, tridecyldimethyl(3-sulfopropyl)ammonium hydroxide intramolecular salt, tetradecyldimethyl(3-sulfopropyl)ammonium hydroxide intramolecular salt, and pentadecyldimethyl(3-sulfopropyl)ammonium hydroxide intramolecular salt. Examples include intramolecular salts, hexadecyldimethyl(3-sulfopropyl)ammonium hydroxide intramolecular salt, heptadecyldimethyl(3-sulfopropyl)ammonium hydroxide intramolecular salt, octadecyldimethyl(3-sulfopropyl)ammonium hydroxide intramolecular salt, nonadecyldimethyl(3-sulfopropyl)ammonium hydroxide intramolecular salt, icosyldimethyl(3-sulfopropyl)ammonium hydroxide intramolecular salt, henicosyldimethyl(3-sulfopropyl)ammonium hydroxide intramolecular salt, and docosyldimethyl(3-sulfopropyl)ammonium hydroxide intramolecular salt.

[0035] Examples of N-alkyl-N,N-dimethylglycine having an alkyl group with 10 to 22 carbon atoms include N-dodecyl-N,N-dimethylglycine and N-octadecyl-N,N-dimethylglycine.

[0036] Examples of nonionic surfactants include higher alcohol ethylene oxide adducts.

[0037] Examples of higher alcohols include 1-hexyl alcohol, 1-heptyl alcohol, 1-octyl alcohol, 1-nonyl alcohol, 1-decyl alcohol, 1-undecyl alcohol, 1-dodecyl alcohol, 1-tridecyl alcohol, 1-tetradecyl alcohol, 1-pentadecyl alcohol, 1-hexadecyl alcohol, 1-heptadecyl alcohol, and 1-octadecyl alcohol.

[0038] The number of moles of ethylene oxide added is preferably 5 to 50, more preferably 5 to 40, and even more preferably 5 to 30, from the viewpoint of odor discrimination performance.

[0039] The weight ratio of the resin (A) to the surfactant (B) [(A) / (B)] is preferably 1.0 to 50.0 from the viewpoint of odor identification performance.

[0040] The resin (A) and the surfactant (B) may or may not be compatible.

[0041] From the viewpoint of dispersibility in the conductive carbon material (C), surfactant (B) is preferably a nonionic surfactant. Furthermore, from the viewpoint of dispersibility in the conductive carbon material (C), surfactant (B) is preferably having at least one of an amide group, a primary amino group, a secondary amino group, or a tertiary amino group. Furthermore, from the viewpoint of dispersibility in the conductive carbon material (C), surfactant (B) is preferably having at least one of an oxyethylene chain, an oxypropylene chain, and a random or block structure of oxyethylene-oxypropylene. The random structure of oxyethylene-oxypropylene is a chain-like structure in which both oxyethylene and oxypropylene are irregularly linked. The block structure of oxyethylene-oxypropylene is a chain-like structure in which oxyethylene blocks, in which oxyethylene is linked, and oxypropylene blocks, in which oxypropylene is linked, are linked.

[0042] <Conductive carbon material (C)> A resin composition according to one embodiment of the present invention contains a conductive carbon material (C). In this specification, the conductive carbon material (C) is a carbon material with a volume resistivity of 0.1 Ω·cm or less. The above-described resin composition is in a state in which the conductive carbon material (C) is dispersed in a resin (A). The resin composition becomes conductive when the conductive carbon material (C) particles come into contact with each other and form conductive paths.

[0043] Examples of conductive carbon materials (C) include carbon black, carbon nanotubes, and graphene.

[0044] Commercially available carbon black products include Ketjenblack EC (product name from Akzo, Netherlands), Ketjenblack EC-300J (product name from Lion Specialty Chemicals Co., Ltd.), Ketjenblack EC-600JD (product name from Lion Specialty Chemicals Co., Ltd.), Seast G116, 116 (product names from Tokai Carbon Co., Ltd.), Nitelon #10 (product name from Nippon Steel Chemical Co., Ltd.), Denka Black (product name from Denki Kagaku Kogyo Co., Ltd.), and SUPER C-65 (product name from MTI Corporation, USA).

[0045] Commercially available carbon nanotubes include VGCF-H (various product names from Showa Denko Corporation), among others.

[0046] Sigma-Aldrich is one company that manufactures commercially available graphene.

[0047] The shape of the conductive carbon material (C) is preferably fibrous or spherical.

[0048] If the material is fibrous, the fiber diameter is preferably 0.1 to 10 μm, and more preferably 0.1 to 5 μm. The fiber length is preferably 0.1 to 10 μm, and more preferably 1 to 10 μm.

[0049] When the particles are spherical, the primary particle diameter is preferably 10 nm to 200 nm, and more preferably 20 nm to 150 nm.

[0050] Furthermore, from the viewpoint of conductivity in the resin composition and sensor sensitivity, the conductive carbon material preferably has a primary particle diameter of 100 nm or less. The particle diameter of the conductive carbon material can be determined by known methods. For example, the particle diameter of the conductive carbon material can be observed with a transmission electron microscope (TEM) and measured by image analysis using an image processing device (e.g., Keyence's VHX-700F digital microscope). If the conductive carbon material is a known or commercially available product, the particle diameter may be a literature value or a catalog value.

[0051] The content of the conductive carbon material (C) is preferably 5 to 30% by weight relative to 100% by weight of the total of the resin (A), surfactant (B), and conductive carbon material (C), from the viewpoint that the sensor element formed from the resin composition exhibits sufficient conductivity as an odor sensor and that it exhibits sufficient sensitivity as an odor sensor.

[0052] The resin composition may further contain other components besides the aforementioned resin (A), surfactant (B), and conductive carbon material (C), to the extent that the effects of the present invention are obtained. Examples of other components include solvents (D). These other components can be suitably used to the extent that both the effects of the present invention and the effects of the other components are obtained.

[0053] Solvent (D) can be incorporated into the resin composition from the viewpoint of improving the compatibility between the resin (A) and the surfactant (B), improving the dispersibility of the conductive carbon material (C) in the resin composition, or improving the coatability of the resin composition. Examples of solvent (D) include N-methyl-2-pyrrolidone, propylene glycol monomethyl ether acetate, ethyl butyrate, butyl butyrate, ethyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, toluene, and xylene.

[0054] The content of solvent (D) in the resin composition can be appropriately determined from the above viewpoint. For example, from the viewpoint of coating properties, the content of solvent (D) in the resin composition is preferably 100 to 10,000 parts by weight per 100 parts by weight of the total of resin (A), surfactant (B), and conductive carbon material (C).

[0055] <Method for producing resin compositions> A specific example of a method for producing a resin composition according to one embodiment of the present invention is as follows.

[0056] The resin composition is obtained as a slurry by mixing a resin (A), a surfactant (B), a conductive carbon material (C), and optionally a solvent (D), and uniformly kneading them in a stirrer. When solvent (D) is added, solvent (D) is removed from the resin composition by distillation. Solvent (D) may be removed by distillation from the resin composition produced by uniform mixing, or it may be removed by distillation from the coating film produced during the manufacture of the sensor element described later.

[0057] [2. Sensor element 31] The aforementioned resin composition exhibits different changes in electrical conductivity over time depending on whether odor substance A is adsorbed or odor substance B, which is different from odor substance A, is adsorbed. By utilizing this property, a sensor element 31 capable of detecting and identifying odor substances can be realized.

[0058] The following describes the overview and effects of a sensor element 31 to which a resin composition according to one embodiment of the present invention is applied.

[0059] The sensor element 31 comprises an odor substance receiving layer 315 containing the above-mentioned resin composition, a first metal wiring 313A, and a second metal wiring 313B. In the following, when the first metal wiring 313A and the second metal wiring 313B are not distinguished, they may be referred to simply as metal wiring 313.

[0060] Here, the first metal wiring 313A and the second metal wiring 313B will be explained using Figures 2 and 3. Figure 2 is a top view showing an example of the configuration of the sensor element 31, and Figure 3 is a cross-sectional view showing an example of the configuration of the sensor element 31 shown in Figure 2.

[0061] The first metal wiring 313A and the second metal wiring 313B are metal wirings that function as electrodes for measuring changes in the electrical conductivity of the odor substance receiving layer 315 (i.e., the resin composition). That is, the first metal wiring 313A and the second metal wiring 313B are spaced apart from each other, and the odor substance receiving layer 315 is in contact with at least a portion of the first metal wiring and at least a portion of the second metal wiring. In one example, the first metal wiring 313A and the second metal wiring 313B are metal wirings that are not in direct contact with each other, and may be substantially parallel to each other, as shown in Figure 2.

[0062] As shown in Figure 2, the metal wiring 313, including the first metal wiring 313A and the second metal wiring 313B, may be arranged on a substrate 311. The substrate 311 may be a substrate such as glass epoxy, which is commonly used in electronic circuits. The metal wiring 313 may be a metal wiring such as copper or gold. The thickness of the first metal wiring 313A and the second metal wiring 313B, as viewed from a direction perpendicular to the surface of the substrate, is preferably 10 μm to 2 mm, and more preferably 10 μm to 1 mm. The height, i.e., thickness, of the first metal wiring 313A and the second metal wiring 313B, as viewed from a direction parallel to the surface of the substrate, is preferably 1 μm to 100 μm, and more preferably 10 μm to 50 μm. The spacing between the first metal wiring 313A and the second metal wiring 313B is preferably 1 μm to 3 mm, and more preferably 1 μm to 1.5 mm. The length of the metal wiring 313 is preferably 100 μm to 50 mm, and more preferably 500 μm to 30 mm.

[0063] Figure 3 shows the AA cross-section of Figure 2. The odor substance receiving layer 315 may be in contact with at least a portion of the first metal wiring 313A and at least a portion of the second metal wiring 313B. The odor substance receiving layer 315 may be arranged to fill the region sandwiched between the first metal wiring 313A and the second metal wiring 313B, for example, as shown in Figures 2 and 3.

[0064] If the electrical conductivity of the odor substance receiving layer 315 (i.e., the electrical conductivity of the sensor element 31) is low, it is desirable that the distance between the first metal wiring 313A and the second metal wiring 313B be less than or equal to a predetermined distance (for example, 500 μm).

[0065] The sensor element 31 can detect and identify various odor substances by applying a resin composition in which the change in electrical conductivity over time differs depending on whether odor substance A is adsorbed or odor substance B, which is different from odor substance A, is adsorbed. In the odor sensor 30 described later, multiple sensor elements 31 may be arranged, each having a substrate 311 equipped with a configuration for detecting odor substances (metal wiring 313 and odor substance receiving layer 315). Multiple sets of odor substance receiving layers 315 with the same composition may be arranged on each substrate 311. Furthermore, it is preferable that the difference in area between each substrate 311 equipped with the sensor element 31 is within 10%. When multiple sensor elements 31 are arranged, each sensor element 31 is provided with a constant voltage power supply and a voltmeter. In the odor sensor 30, one configuration for detecting odor substances (metal wiring 313 and odor substance receiving layer 315) may be arranged on each substrate 311. Alternatively, in the odor sensor 30, multiple sets of components for detecting odor substances (metal wiring 313 and odor substance receiving layer 315) may be arranged on a single substrate 311. In the latter case, a constant voltage power supply and a voltmeter are connected to each of the sets provided on the substrate 311.

[0066] The composition of each of the multiple odor substance receiving layers 315 in the odor sensor 30 may be the same or different. If the odor sensor 30 includes odor substance receiving layers 315 with the same composition, the same odor substance can be detected in each of the multiple odor substance receiving layers 315. If the odor sensor 30 includes odor substance receiving layers 315 with different compositions, each of the multiple odor substance receiving layers 315 will respond differently to the odor substance. In this way, by providing multiple sets of configurations for detecting odor substances, the accuracy of odor substance identification in the odor sensor 30 can be improved. Furthermore, as will be described later, it is preferable that the difference in the number of sensor elements 31 arranged in each of the passages 61 to 64 is 10 or less. In addition, it is preferable that the size of each sensor element 31 is approximately the same. Here, the number of sensor elements 31 is determined based on the number of substrates 311. Thus, whether one set of configurations for detecting odor substances is arranged on the substrate 311 or multiple sets are arranged, the number of sensor elements 31 is determined based on the number of substrates 311 arranged in each passage. Since the length of each passage is affected by the size of the substrate 311, the number of sensor elements 31 to be arranged is determined based on the number of substrates 311 as described above, thereby keeping the difference in length between each passage within a desirable range.

[0067] [3. Odor Sensor 30] Below, the overview and effects of the odor sensor 30 to which the sensor element 31 is applied will be explained using Figure 4. Figure 4 is a block diagram showing an example of the configuration of the odor sensor 30 to which the sensor element 31 is applied.

[0068] The odor sensor 30 includes a sensor element 31 for detecting odor substances, a constant voltage power supply 32 (power supply), and a voltmeter 33 (measuring instrument).

[0069] The first metal wiring 313A and the second metal wiring 313B of the sensor element 31 are connected by a lead wire W. Figure 4 shows an example in which a constant voltage power supply 32 and a voltmeter 33 are connected to the lead wire W.

[0070] The constant voltage power supply 32 is a power source for supplying power to the sensor element 31. The constant voltage power supply 32 supplies a constant voltage to the sensor element 31 via lead wires. The voltage value supplied by the constant voltage power supply 32 is 0.5V to 10V, for example, 2.5V or 5.0V.

[0071] The voltmeter 33 measures the potential difference that occurs between the first metal wiring 313A and the second metal wiring 313B when a constant voltage supplied from the constant voltage power supply 32 is supplied to the odor substance receiving layer 315.

[0072] Furthermore, the odor sensor 30 is equipped with an amplifier (not shown) in the circuit for measuring odor substances, prior to the voltmeter 33, and this amplifier amplifies the acquired signal and supplies it to the voltmeter 33.

[0073] Furthermore, the odor sensor 30 is equipped with a reference circuit in addition to the circuit for measuring odor substances, and the voltmeter 33 acquires the difference (potential difference) between the value obtained in the odor substance measurement circuit and the value obtained in the reference circuit as a voltage value.

[0074] The odor sensor 30 may also be further equipped with a housing 34, although this is not a mandatory configuration. The housing 34 is a container capable of enclosing air containing odor substances. If a housing 34 is provided, the sensor element 31 is installed inside the housing 34.

[0075] The housing 34 is equipped with an inlet 341 for introducing odor substances and an outlet 342 for discharging air containing odor substances. The introduction of odor substances may be performed by introducing filter paper or the like soaked in odor substances into the housing 34 through the inlet 341, or by introducing air containing odor substances into the housing 34 through the inlet 341. The housing 34 is a container for enclosing air containing odor substances at a predetermined concentration (for example, 200 ppm) or higher.

[0076] Although not mandatory, an airflow generating fan 35 may be provided at the exhaust port 342 of the housing 34. The airflow generating fan 35 is used to create airflow inside the housing 34 or to expel the gas inside the housing 34 to the outside of the housing 34 through the exhaust port 342.

[0077] The odor sensor 30 may also be equipped with a constant current source (power supply) (not shown) as a substitute for the constant voltage power supply 32, and an ammeter (measuring instrument) (not shown) as a substitute for the voltmeter 33. In this case, the constant current source functions as a power supply for supplying power to the sensor element 31, applying a constant current to the sensor element 31 via lead wires. The ammeter, on the other hand, measures the current flowing between the first metal wiring 313A and the second metal wiring 313B when a constant voltage is applied to the odor substance receiving layer 315.

[0078] The odor sensor 30 outputs a measurement value that shows the change in the electrical conductivity of the sensor element 31 over time, before and after odor substances are adsorbed onto the sensor element 31. This makes it possible to detect and identify various odor substances.

[0079] [4. Odor measuring device 100] The odor sensor 30 described above can output the change in the electrical conductivity of the sensor element 31 over time for each odor substance when various odor substances are adsorbed onto the sensor element 31. By applying this odor sensor 30, it is possible to compare the change in the electrical conductivity of the sensor element 31 over time when odor substance A is adsorbed onto the sensor element 31 with the change in the electrical conductivity of the sensor element 31 over time when odor substance B is adsorbed onto the sensor element 31. Based on such comparison results, an odor measuring device 100 can be realized that can estimate the odor substances adsorbed onto the sensor element 31.

[0080] Furthermore, the odor measuring device 100 can perform highly accurate estimation of odor substances by using an estimation model 22 generated by machine learning. The estimation model 22 can be generated using training data that includes a combination of measurement values ​​obtained when each of several odor substances is adsorbed onto at least one sensor element 31, and identification information specific to the odor substance to which the measurement value was obtained.

[0081] The following describes the overview and effects of the odor measuring device 100 to which the odor sensor 30 is applied. The odor measuring device 100 is a device that estimates odor substances adsorbed on a sensor element 31 from the change in electrical conductivity that occurs in the sensor element 31 to which the above-described resin composition is applied. The odor measuring device 100 of this embodiment separately comprises a sensor chamber 60 equipped with a plurality of sensor elements 31A (hereinafter also referred to as the "sensor element group 31A") and a target sample receiving section 50 into which a target sample containing odor substances is introduced and which contains a gas containing odor substances generated from the target sample. In this embodiment, each sensor element included in the sensor element group 31A is simply referred to as a "sensor element".

[0082] The odor measuring device 100 of this embodiment employs a configuration in which the gas containing the odor substance inside the target sample receiving section 50 is pushed towards the sensor chamber 60 using another gas (carrier gas). In this embodiment, the gas inside the target sample receiving section 50 when the target sample is introduced into the target sample receiving section 50 (i.e., the gas containing the odor substance to be detected) is referred to as the first gas. On the other hand, the carrier gas used to push the first gas towards the sensor chamber 60 is referred to as the second gas.

[0083] Figure 1 is a schematic diagram of the odor measuring device 100. As shown in Figure 1, the odor measuring device 100 comprises an odor sensor 30, a target sample receiving section 50, a sensor chamber 60, a gas supply section 80, and an estimation device 10. The odor measuring device 100 may also further include a control section 51. Furthermore, the odor measuring device 100 may further include an estimation device 10a.

[0084] Figure 1 shows an example in which gas flows from the gas supply unit 80 to the target sample receiving unit 50 and then to the sensor chamber 60. The gas supply unit 80, the target sample receiving unit 50, and the sensor chamber 60 are connected by pipes.

[0085] [Target sample receiving section 50] The target sample receiving section 50 is capable of receiving a target sample containing odor substances and holding the first gas. The target sample receiving section 50 includes a first port 501 through which the second gas entering the interior passes, and a second port 502 through which the first gas and the second gas exiting the interior can pass. The target sample receiving section 50 may also include a sample inlet 503, which will be described later.

[0086] Figure 1 shows a configuration in which the first port 501 is installed at the top of the paper surface of the sample receiving section 50 and the second port 502 is installed at the bottom of the paper surface of the sample receiving section 50, but is not limited to this configuration. For example, the positions of the first port 501 and the second port 502 can be appropriately set depending on the type and combination of odor components contained in the first gas. For example, the positions of the first port 501 and the second port 502 may be changed depending on whether the weight per unit volume (i.e., specific gravity) of the odor components contained in the first gas is heavier or lighter than that of the second gas. The sample receiving section 50 may also be equipped with an airflow generating fan 35 inside.

[0087] The sample receiving section 50 is equipped with a sample inlet 503 for receiving a liquid or solid sample. The sample receiving section 50 may also be equipped with a placement section (not shown) for placing the sample. If the sample is liquid, the placement section may be a cup for holding the liquid, and if the sample is solid, the placement section may be a petri dish in which the solid is placed. The sample may be introduced into the sample receiving section 50 in a gaseous state as a first gas from the sample inlet 503. In this way, because the sample receiving section 50 is capable of receiving a liquid or solid sample, it is possible to adjust the concentration of odorants in the first gas. For example, even with the same odorant, it is easy to adjust the level of concentration of the odorant in the first gas.

[0088] The inner surface of the sample receiving section 50 may be made of a material that is inert to odor substances. A material that is inert to odor substances is a material that does not significantly change the concentration of each odor substance contained in the gas sent to the sensor chamber 60. For example, a material that is inert to odor substances is a material that odor substances do not easily adsorb or dissolve into. Examples of materials that are inert to odor substances include glass, metal, and resin. When using metal, stainless steel (SUS) is preferred, and when using resin, fluororesin, polypropylene (PP), polyethylene (PE), ABS resin, and polyethylene terephthalate (PET) are preferred.

[0089] If the inner surface of the sample receiving section 50 is made of a material that adsorbs odor substances contained in the first gas, odor substances may be adsorbed onto each part, potentially affecting subsequent measurements.

[0090] Because the inner surface of the sample receiving section 50 is made of a material that is inert to odor substances, the risk of the inner surface material reacting with the odor substances contained in the first gas, or of odor substances being adsorbed onto the inner surface, is reduced. Therefore, the risk of the odor substances contained in the first gas supplied to the sensor chamber 60 changing while they are contained within the sample receiving section 50, or of the concentration of odor substances becoming diluted, is reduced.

[0091] The odor measuring device 100, by including a sample receiving section 50, can equalize the concentration of the first gas within the sample receiving section 50 before sending the first gas to the sensor chamber 60, even if the target sample is a liquid or solid. Furthermore, the odor measuring device 100, by including a sample receiving section 50, can push the first gas into the sensor chamber 60 at a constant flow rate. As a result, even when measurements are repeated, the odor measuring device 100 can send the first gas to the sensor chamber 60 under the same conditions each time, enabling stable and repeated measurements.

[0092] The volume of the sample receiving section 50 is preferably 1 to 200 times the volume of the sensor chamber 60. In particular, it is preferable that the volume of the sample receiving section 50 is larger than the volume of the sensor chamber 60. More preferably, the volume of the sample receiving section 50 is 2 times or more the volume of the sensor chamber 60, and even more preferably 4 times or more. Furthermore, it is preferable that the volume of the sample receiving section 50 is 100 times or less the volume of the sensor chamber 60, and even more preferably 60 times or less. By having a volume of the sample receiving section 50 that is 1 or more times the volume of the sensor chamber 60, the concentration of odor substances in the sensor chamber 60 is appropriately adjusted, and the measurement results from the sensor in the sensor chamber 60 are stably output. In addition, by having a volume of the sample receiving section 50 that is 200 times or less the volume of the sensor chamber 60, it is easier to adjust the temperature and humidity inside the sample receiving section 50, so that the measurement results from the sensor are stably output, and the size of the odor measuring device 100 can be made compact.

[0093] If the volume of the sample receiving section 50 is less than one times the volume of the sensor chamber 60, odor substances generated in the sample receiving section 50 may be diluted in the sensor chamber 60, potentially reducing the measurement sensitivity of the sensor. Furthermore, if the volume of the sample receiving section 50 is greater than 200 times the volume of the sensor chamber 60, the volume of the sample receiving section 50 is too large, which may reduce the uniformity of the concentration, temperature, and humidity of the first gas, making it impossible to repeatedly supply the first gas to the sensor chamber 60 under the same conditions. Additionally, the overall size of the odor measuring device 100 may increase.

[0094] Figure 1 shows an example where the volume inside the target sample receiving section 50 is eight times the volume inside the sensor chamber 60.

[0095] For example, if the inner surface of the tube 93 is made of a material that adsorbs odor substances contained in the first gas, odor substances may be adsorbed on various parts, potentially affecting subsequent measurements. Therefore, it is preferable that the inner surface of the tube 93, which guides the first gas from the target sample receiving section 50 to the sensor chamber 60, be made of a material that is inert to odor substances, similar to the inner surface of the target sample receiving section 50. Examples of materials that are inert to the first gas include glass, metal, and resin. When using metal, stainless steel (SUS) is preferred, and when using resin, fluororesin, polypropylene (PP), polyethylene (PE), ABS resin, and polyethylene terephthalate (PET) are preferred.

[0096] The target sample receiving section 50 may be configured to be detachable from the tubes 92 and 93. By making the target sample receiving section 50 detachable, when the previous measurement is completed and the next measurement is to be performed, a new target sample receiving section 50 can be attached without purging the inside of the current section 50. This allows the odor measuring device 100 to perform multiple measurements in a short amount of time.

[0097] Furthermore, because the sample receiving section 50 is detachable, the sample receiving section 50 into which the sample has been introduced can be maintained at a desired temperature using a separate insulated chamber from the odor measuring device 100. This means that, for example, even if the adjustment section 51 described later cannot be provided in the odor measuring device 100, the odor measuring device 100 can adjust the temperature of the sample receiving section 50.

[0098] [Adjustment section 51] The adjustment unit 51 adjusts at least one of the temperature and humidity of the first gas contained within the target sample receiving unit 50. When the adjustment unit 51 adjusts the temperature, it is, for example, a heater or a cooler. In this case, the adjustment unit 51 may be configured to cover the entire target sample receiving unit 50. When the adjustment unit 51 adjusts the humidity, it is, for example, a humidifier or a dehumidifier. The adjustment unit 51 may adjust at least one of the temperature and humidity for each type of first gas, or it may change at least one of the temperature and humidity at predetermined intervals during measurement of the same first gas.

[0099] The adjustment unit 51 adjusts at least one of the temperature and humidity of the first gas in the target sample receiving unit 50, thereby enabling the odor measuring device 100 to send the first gas to the sensor chamber 60 under conditions corresponding to, for example, the type of first gas (gas weight, volatility, etc.). Furthermore, this allows the odor measuring device 100 to send the first gas at a stable concentration to the sensor chamber 60, improving the accuracy of the measurement.

[0100] [Gas supply unit 80] The gas supply unit 80 is connected to the first port 501 of the target sample receiving unit 50, and by sending the second gas into the target sample receiving unit 50, the first gas is sent from inside the target sample receiving unit 50 toward the sensor chamber 60.

[0101] A valve 81 may be provided between the gas supply unit 80 and the target sample receiving unit 50. The start and stop of gas supply from the gas supply unit 80 may be adjusted by opening and closing the valve 81.

[0102] In this way, the gas supply unit 80 pushes the gas from the first port 501 side of the target sample receiving unit 50, sending the first gas into the sensor chamber 60, so the pressure inside the sensor chamber 60 is positive. Therefore, the odor measuring device 100 can obtain stable measurement results. In addition, since the second gas can be supplied by opening and closing the valve 81, the odor measuring device 100 can send the first gas from the target sample receiving unit 50 to the sensor chamber 60 at any timing. As a result, when the odor measuring device 100 repeatedly measures odor substances contained in the first gas using the sensor element group 31A, the reproducibility of the waveform shape output by each sensor element can be improved.

[0103] The second gas may be an inert gas or air. Examples of inert gases include argon and nitrogen. If the second gas is an inert gas, the gas supply unit 80 may be a gas cylinder.

[0104] Furthermore, if the second gas is air, the gas supply unit 80 may be a pump. In this case, in order to remove components that react with the first gas contained in the target sample receiving unit 50, the odor measuring device 100 may, for example, be equipped with an activated carbon filter on the first port 501 side of the target sample receiving unit 50.

[0105] The odor measuring device 100 may further include a mass flow controller between the first port 501 side of the target sample receiving section 50, more specifically between the valve 81 and the gas supply section 80. With this configuration, the odor measuring device 100 can send the first gas from the target sample receiving section 50 to the sensor chamber 60 at a constant flow rate, and the sensor elements of the sensor element group 31A can stably output.

[0106] [Sensor Chamber 60] The sensor chamber 60 is a space that houses a group of sensor elements 31A for measuring odor substances. The sensor chamber 60 is connected to the second port 502 of the target sample receiving section 50. Specifically, the sensor chamber 60 is equipped with a gas supply port 601 and a gas outlet 602, and the second port 502 of the target sample receiving section 50 is connected to the gas supply port 601.

[0107] The sensor chamber 60 has multiple passages, each containing multiple sensor elements 31A capable of outputting measurement results corresponding to odor substances contained in the gas. This reduces the time required from the start of supplying gas to the sensor chamber 60 until measurement results are stably output from all of the multiple sensor elements 31A. Furthermore, by dividing the multiple sensor elements 31A into multiple passages, the variation in airflow turbulence from measurement to measurement is reduced, thereby improving measurement accuracy.

[0108] Figure 5 is a top view showing an example configuration of the sensor chamber 60. Figure 5 shows a sensor chamber 60 having four passages (i.e., passage 61, passage 62, passage 63, and passage 64). The first gas can be supplied from the target sample receiving section 50 to each of the passages 61 to 64.

[0109] Multiple sensor elements 31A may be arranged in each of the multiple passages (passages 61 to 64), each outputting a different measurement result for each odor substance. The multiple sensor elements 31A that output different measurement results for each odor substance may each be a sensor element 31 having a different resin composition as its substance receiving layer. That is, the multiple sensor elements 31A arranged in one passage may have different sensitivity and detection specificity for each odor substance. The sensor chamber 60 in Figure 5, as an example, includes a sensor element 31 and a sensor element 31b in passage 61, but is not limited thereto. For example, sensor elements 31 and 31b may both be capable of outputting measurement results corresponding to the same odor substance contained in the first gas, but the measurement results output by each sensor element may be different. Also, sensor elements 31 and 31b may each be capable of outputting measurement results corresponding to different odor substances. For example, the odor sensor 30 may include sensor elements 31 and 31b whose odor substance receiving layers 315 have different resin compositions. The measurement results corresponding to the odor substance are, for example, measurement results corresponding to the concentration of the odor substance. In the following description, unless otherwise distinguished, sensor elements 31, 31b, 31c and sensor elements 31d to 31g described later will be collectively referred to as "sensor element 31". By arranging multiple sensor elements that output different measurement results for each odor substance in each of the multiple passages, the odor measuring device 100 can detect odor substances passing through a single passage using sensor elements 31 with different sensitivities and detection specificities. As a result, the odor measuring device 100 can comprehensively detect odor substances from multiple different measurement results.

[0110] By providing multiple sensor elements using resin compositions with different odor-adsorbing properties in the odor-receiving layer 315, the odor measuring device 100 can simultaneously perform estimations for multiple odor substances. In addition to the sensor elements according to one embodiment of the present invention, sensor elements that do not contain surfactant (B) in the odor-receiving layer 315 may also be used.

[0111] Furthermore, if the odor measuring apparatus 100 is used, for each known odor substance, it is possible to obtain a first change pattern indicating a change in electrical conductivity of the sensor element 31 and a second change pattern indicating a change in electrical conductivity of the sensor element 31b. The estimation model 22 may be generated by machine learning using both the first change pattern and the second change pattern. Since the odor measuring apparatus 100 estimates an odor substance using the estimation model 22 generated in this manner, it is possible to identify each odor substance more precisely.

[0112] Furthermore, in FIG. 5, similarly to the passage 61, the passage 62 is provided with a plurality of sensor elements 31A (such as sensor elements 31c and 31d) capable of outputting measurement results corresponding to odor substances contained in a first gas. The passage 63 is provided with a plurality of sensor elements 31A (such as sensor elements 31e and 31f) capable of outputting measurement results corresponding to odor substances contained in the first gas. The passage 64 is provided with a plurality of sensor elements 31A (such as sensor elements 31g and 31h) capable of outputting measurement results corresponding to odor substances contained in the first gas. The plurality of sensor elements 31A may be sensor elements in which the resin compositions used for the substance-receptive layers 315 are different from each other.

[0113] Note that some of the sensor elements 31 to 31h may be sensor elements having the same detection specificity for odor components. That is, for example, when the sensor element group 31A disposed in the sensor chamber 60 includes n sensor elements 31, m types (m < n) of sensor elements 31 may be disposed. Furthermore, some of the plurality of sensor elements 31A disposed in the same passage may have the same detection specificity for odor components.

[0114] Furthermore, the sensor chamber 60 has passages 61 to 64, and a plurality of sensor elements 31A may be disposed in each of the passages 61 to 64. In this case, the plurality of sensor elements 31A disposed in each of the passages 61 to 64 constitute the sensor element group 31A. For example, four sensor elements 31 may be disposed in the passage 61, and ten sensor elements 31 may be disposed in the passage 62.

[0115] When a different number of sensor elements 31 are arranged in each of the passages 61 to 64, it is preferable that the difference in the number of sensor elements 31 arranged in each of the passages 61 to 64 is 10 or less. By having a difference of 10 or less in the number of sensor elements 31 arranged in each of the passages, it is possible to reduce the variation in the timing at which odor substances that may be generated in each passage are detected by the sensor elements 31. In addition, by having a difference of 10 or less in the number of sensor elements 31 arranged in each of the passages 61 to 64, the odor measuring device 100 can perform odor measurement in a short time.

[0116] Each of the passages is connected to a pipe 93 for supplying the first gas into the internal space of the sensor chamber 60. As shown in Figure 5, passages 61, 62, 63, and 64 are all connected to a single pipe 93.

[0117] Furthermore, the cross-sectional area of ​​each passage perpendicular to the supply direction in which the first gas is supplied from the pipe 93 may be smaller than the cross-sectional area perpendicular to the axial direction of the pipe 93. This allows the first gas supplied from the target sample receiving section 50 to pass through each passage at a faster flow velocity than when passing through the pipe 93. This minimizes the time lag in measurements between the sensor element 31 located closer to the gas supply port 601 and the sensor element 31 located closer to the gas outlet 602, enabling the odor measuring device 100 to perform highly accurate measurements.

[0118] Furthermore, it is preferable that the gas in each internal space of the passage is replaced within 1 second after the supply of the first gas is started. The start of the supply of the first gas is when the first gas is supplied to the gas supply port 601. The replacement of the gas in the internal space indicates that the first gas supplied from the gas supply port 601 has reached the gas outlet 602. In this way, by replacing the gas in each internal space of the passage within 1 second after the supply of the first and second gases is started, the timing difference in when the first gas comes into contact with each sensor element 31 is reduced, and the odor measuring device 100 can perform measurements stably. In addition, by replacing the gas in each internal space of the passage within 1 second after the supply of the first and second gases is started, the odor measuring device 100 can perform odor measurements in a short time.

[0119] The flow velocity of the first gas passing through each internal space of the passage is preferably 0.1 cm / s or more and 100 cm / s or less. More preferably, the flow velocity of the first gas passing through each internal space of the passage is 1 cm / s or more and 50 cm / s or less. The flow velocity of the first gas passing through each internal space of the passage may be adjusted, for example, by the degree of pressurization of the gas supply unit 80 described later, or by the mass flow controller described later.

[0120] If the flow velocity of the first gas passing through each internal space of the passage is slow, the timing difference in when the first gas touches all the sensor elements 31 of the sensor element group 31A will increase. On the other hand, if the flow velocity of the first gas passing through each internal space of the passage is too fast, the sensor elements 31 of the sensor element group 31A will vibrate due to the influence of the airflow, and the odor measuring device 100 will not be able to perform stable odor measurement. Furthermore, if the flow velocity of the first gas passing through each internal space of the passage is too fast, the adsorption of odor substances contained in the first gas onto the sensor elements 31 of the sensor element group 31A will be inhibited, and the odor measuring device 100 will not be able to perform accurate odor measurement. In addition, if the flow velocity of the first gas passing through each internal space of the passage is too fast, there is a risk that the first gas in the target sample receiving section 50 will be consumed before the odor measuring device 100 can perform a stable measurement.

[0121] Thus, by ensuring that the flow velocity of the first gas passing through each internal space of the passage is between 0.1 cm / s and 100 cm / s, the odor measuring device 100 can perform odor measurements stably.

[0122] Each of the passages may be arranged in parallel. In Figure 5, passages 61 to 64 are arranged in parallel to each other. By arranging each of the passages in parallel in this way, the odor measuring device 100 can secure space for arranging the passages and make the overall size of the device compact.

[0123] Furthermore, passages 61 to 64 each have the same length in the supply direction (indicated by arrow X in Figure 5) in which the first gas is supplied from the pipe 93. In other words, the length from the gas supply port 601 to the gas outlet 602 is the same in each of passages 61 to 64. Note that "same length" does not mean that the lengths are exactly the same, but a slight difference is also acceptable. The allowable difference in length between passages is preferably 20% or less, and most preferably 10% or less. If the supplied first gas has a sufficiently fast flow velocity, the lengths of passages 61 to 64 in the supply direction may differ further. For example, the difference in length between the longest and shortest passages may be 50% or less. By setting the length of each passage in this way, the timing difference in when the first gas finishes passing through each passage can be reduced. This also reduces the timing difference in when the first gas that has passed through each passage reaches the gas outlet 602.

[0124] Figure 6 is a schematic cross-sectional view showing the cross-section along line BB in Figure 5. The passage 61 in Figure 6 is composed of a side wall 610, a side wall 611 opposite to the side wall 610, a ceiling 621, and a base plate 630 which is the bottom surface.

[0125] In Figure 6, a sensor chamber 60 is shown in which the cross-sectional shape of the passage 61 is rectangular, but the cross-sectional shape of the passage 61 is not particularly limited. For example, the cross-sectional shape of the passage 61 may be an arc or a triangle.

[0126] The passage 61 and the passage 62 are completely separated by side walls 611 and 612, and the configuration may be such that gas cannot enter or leave the space between the passage 61 and the passage 62.

[0127] In Figure 6, as an example, there are two side walls (side wall 611 and side wall 612) between passage 61 and passage 62, but the configuration is not limited to this. For example, passage 61 and passage 62 may be separated by a single side wall.

[0128] The sensor chamber 60 in Figure 6 is formed as a single unit, but the configuration is not limited to this. The sensor chamber 60 may be formed as a single unit, or each of the multiple passages may be formed as a separate unit.

[0129] The sensor chamber 60 in Figure 6, for example, has a sensor element 31 on the substrate 630 which is the bottom surface of the passage 61, but the arrangement of the sensor element 31 is not limited to this. The sensor element 31 may be arranged considering, for example, the type of odor substance that the sensor element 31 can specifically detect. For example, the sensor element 31 may be placed on the side wall 610, the side wall 611, or the ceiling 621. Specifically, if the odor substance is lighter than air, the sensor element 31 may be placed on the ceiling 621. With this configuration, the odor measuring device 100 can perform highly accurate measurements by arranging the sensor element 31 in a location corresponding to the type of odor substance.

[0130] In Figure 6, the sensor chamber 60 is provided with each sensor element 31 on the substrate 630, but it may also be further provided with a connector between the substrate 630 and each sensor element 31 to connect the substrate 630 and the sensor element 31.

[0131] Each sensor element 31 may be connected to the circuit board 630 independently. For example, each sensor element 31 may be connected to the circuit board 630 via a connector (e.g., IC pins). In this case, even if only one of the sensor elements 31 included in the sensor chamber 60 malfunctions, the user can replace only the malfunctioning sensor element 31.

[0132] Furthermore, when detecting odor substances using multiple types of sensor elements 31, the optimal combination of sensor elements 31 and the optimal arrangement of the sensor elements 31 vary depending on the type of odor substance. Since each sensor element 31 is independently connected to the substrate 630 and is detachable, the odor measuring device 100 can be easily modified to accommodate the optimal combination and arrangement of sensor elements 31 according to the odor substance.

[0133] The sensor element 31 may be placed in two or more locations on the substrate 630, side wall 610, side wall 611, and ceiling 621. This allows the length of the passage 61 to be shortened compared to when the sensor element 31 is provided on only one side, thus making the odor measuring device 100 more compact. In addition, since multiple sensor elements 31 can be provided in locations close to the gas supply port 601, the odor measuring device 100 can perform odor measurements in a shorter time than when the sensor elements 31 are arranged in a line facing the gas outlet 602.

[0134] The sensor chamber 60 in Figure 6, as an example, has four passages, with one sensor element 31 arranged in each of them in the cross-sectional direction, but the number of passages and the number of sensor elements 31 in the cross-sectional direction are not limited to this. Figure 7 shows a cross-sectional view of the sensor chamber 60a. The sensor chamber 60a, as an example, has two passages (passage 61a and passage 62a). In addition, passage 61a has two sensor elements 31 (i.e., sensor element 31 and sensor element 31c) in the cross-sectional direction. Furthermore, in the sensor chamber 60a, as described above, the sensor elements 31 may not only be arranged on the substrate 630, but may also be arranged in two or more locations on the substrate 630, side wall 610a, side wall 613a, and ceiling 621a. The arrangement of the sensor elements 31 in passage 62a is the same as in passage 61a.

[0135] The material of the inner surface of the sensor chamber 60 is preferably an inert material to odor substances, similar to the material of the sample receiving section 50. Examples of inert materials include glass, metal, and resin. When metal is used, stainless steel (SUS) is preferred, and when resin is used, fluororesin, polypropylene (PP), polyethylene (PE), ABS resin, and polyethylene terephthalate (PET) are preferred. If the material of the inner surface of the sensor chamber 60 is a material that adsorbs odor substances contained in the first gas, the adsorption of odor substances on the sensor chamber may reduce the change in output from the sensor element 31 in subsequent measurements, potentially preventing the odor measuring device 100 from performing accurate measurements.

[0136] [Multiple sensor elements 31A (sensor element group 31A)] The sensor elements of the sensor element group 31A may include thin films. For example, the odor substance receiving layer 315 in Figures 2 and 3 is a thin film.

[0137] One possible method for supplying the first gas containing odor substances into the sensor chamber 60 is to install a vacuum pump on the gas outlet 602 side of the sensor chamber 60 and use the vacuum pump to draw in the gas, thereby supplying the odor substances to the sensor chamber 60 from the gas supply port 601 side. However, if the sensor elements 31 and 31b are equipped with thin films, the thin films may expand if the inside of the sensor chamber 60 is under negative pressure, which could prevent the sensor elements 31 and 31b from outputting stable measurement results. In the odor measuring device 100 according to this embodiment, the gas supply unit 80 pushes the gas from the sensor chamber 60 and the first port 501 side of the target sample receiving unit 50, thereby supplying the first gas to the sensor chamber 60. As a result, the pressure inside the sensor chamber 60 is positive. Therefore, the odor measuring device 100 can obtain stable measurement results even if the sensor elements of the sensor element group 31A are equipped with thin films.

[0138] Furthermore, the thin film of the sensor element 31 in the sensor element group 31A may also contain a conductive carbon material, a resin composition, and a surfactant. Specific embodiments of the sensor element 31 will be described later.

[0139] <Sensor element> The odor measuring device 100 is equipped with two sensor elements 31 and 31b. It is preferable that the shape, area, and thickness of the odor substance receiving layers 315 of the sensor elements 31 and 31b have little variation. This is because if there is variation in the shape, area, and thickness of the odor substance receiving layers 315 of multiple sensor elements 31A, there is a risk that stable measurement of odor substances may not be possible.

[0140] Each sensor element 31 and 31b is equipped with a first metal wire 313A and a second metal wire 313B as electrodes, with the metal wires arranged in parallel (see Figure 2). Furthermore, each sensor element 31 and 31b is equipped with an odor substance receiving layer 315 that fills the region between the first metal wire 313A and the second metal wire 313B. In addition to sensor elements 31 and 31b, the sensor element group 31A may also include a sensor element 31 that differs from sensor elements 31 and 31b in its arrangement of metal wires (i.e., electrodes) 313 and the shape of its odor substance receiving layer 315. In Embodiments 1 and 2, the metal wire 313 was referred to as the electrode 313; this will be referred to as the electrode 313 from now on.

[0141] The sensor element 31 comprises an electrode 313 arranged on a substrate 311 and an odor substance receiving layer 315 formed on the electrode 313. The shape of the odor substance receiving layer 315 is circular or strip-shaped. If the shape of the odor substance receiving layer 315 is circular, the diameter R of the circle is 0.2 mm or more and 5 mm or less. If the shape of the odor substance receiving layer 315 is strip-shaped, the width W in the short direction of the strip may be 0.2 mm or more and 5 mm or less. Here, "strip-shaped" refers to a surface shape that mainly has a width in the short direction and a length in the long direction. In this specification, "strip-shaped" is a shape different from "square-shaped". A strip-shaped shape, as shown in Figure 13, has four corners that form arcs and differs from a square shape in that it does not have corners. When the odor substance receiving layer 315 is circular, the diameter R of the circle is preferably 0.6 mm or more and 4.0 mm or less. When the odor substance receiving layer 315 is strip-shaped, the width W in the short direction of the strip is preferably 0.6 mm or more and 4.0 mm.

[0142] As long as the diameter R or width W of the odor substance receiving layer 315 of the sensor element 31 included in the sensor element group 31A is within the aforementioned range, the odor measuring device 100 can stably perform measurements according to the odor substance.

[0143] If the diameter R of the odor substance receiving layer 315 is less than 0.2 mm, or if the width W is less than 0.2 mm, the area for receiving odor substances becomes small, and the odor measuring device 100 cannot perform measurements stably.

[0144] Furthermore, if the diameter R of the odor substance receiving layer 315 is greater than 5 mm, or if the width W is greater than 5 mm, the area of ​​one of the sensor elements 31 increases, and the size of the sensor chamber 60 including the sensor element group 31A increases. When the size of the sensor chamber 60 increases, it becomes difficult to uniformly diffuse the first gas containing the odor substance into the sensor chamber 60, and therefore the odor measuring device 100 cannot perform measurements stably.

[0145] [Estimation device 10] The estimation device 10 is a device that estimates odor substances detected by the odor sensor 30. The estimation device 10 is, for example, a computer and is equipped with a CPU and memory (not shown). The estimation device 10 is communicably connected to the odor sensor 30. Specifically, the estimation device 10 performs the estimation of odor substances by analyzing the measured values ​​obtained from the odor sensor 30. If the sensor chamber 60 further includes a sensor element 31c that uses a different resin composition for the substance receiving layer 315 than the sensor element 31 and sensor element 31b, the estimation device 10 may further acquire and analyze measured values ​​measured by a voltmeter by supplying a constant voltage to the sensor element 31c. The estimation device 10 may also display the measured values ​​themselves, waveforms plotted from the measured values, and the estimation results of unknown odor substances based on the estimation model. The estimation device 10 may also display numerical values ​​and graphs showing the change in the abundance ratio of each odor substance for a gas containing multiple odor substances. The estimation device 10 may also generate an estimation model 22 used to estimate odor substances.

[0146] <Generation of Estimated Model 22> Next, the configuration of the odor measuring device 100, which performs the process of generating an estimation model 22 used to estimate odor substances, and the process of generating the estimation model 22 will be explained with reference to Figures 8 and 9.

[0147] The estimation model 22 is generated by machine learning using training data that includes a combination of measured values ​​obtained by the voltmeter 33 when each of several odor substances is adsorbed onto at least one sensor element, and identification information specific to the odor substance to which the measured value was obtained. Here, the identification information specific to the odor substance may be, for example, the name of the odor substance, the CAS number, and the chemical formula.

[0148] (Configuration of estimation device 10 (generation of estimation model 22)) Figure 8 is a functional block diagram showing an example of the configuration of the odor measuring device 100. For the sake of clarity, components having the same function as those described in Figure 4 are denoted by the same reference numerals, and their descriptions are not repeated.

[0149] As shown in Figure 8, the estimation device 10 includes an input unit 15, a control unit 1, and a storage unit 2.

[0150] The input unit 15 is for receiving various input operations from the user, and may be, for example, a keyboard, mouse, touch panel, etc.

[0151] The control unit 1 comprises a measurement value acquisition unit 11 (acquisition unit), a change pattern analysis unit 12 (analysis unit), a learning control unit 13, and an estimation model generation unit 14.

[0152] The measurement value acquisition unit 11 acquires measurement values ​​from the voltmeter 33. The measurement value acquisition unit 11 also uses the acquired measurement values ​​to calculate values ​​indicating the electrical conductivity of the sensor element 31 (e.g., resistance and impedance). The measurement value acquisition unit 11 may acquire measurement values ​​from the voltmeter 33 at predetermined time intervals (e.g., 0.1-second intervals).

[0153] The change pattern analysis unit 12 analyzes the change in electrical conductivity of at least one sensor element 31 over time. The change pattern analysis unit 12 uses the resistance value calculated by the measurement value acquisition unit 11 to calculate a value indicating the amount of change in the electrical conductivity of the sensor element 31 due to the adsorption of odor substances. The change pattern analysis unit 12 generates data showing a change pattern that indicates the time change of the calculated amount of change in electrical conductivity. If the generated change pattern is that of a known odor substance, the change pattern analysis unit 12 may associate the generated change pattern with identification information specific to the known odor substance and store it in the change pattern database 21 (training data).

[0154] The learning control unit 13 reads the change pattern database 21 from the memory unit 2 and controls the generation of an estimation model 22 using machine learning. Here, the change pattern database 21 is a database that includes combinations of measured values ​​obtained when multiple odor substances are adsorbed onto the sensor element 31 and identification information unique to the known odor substances to which the measured values ​​were given. The learning control unit 13 inputs the change patterns read from the change pattern database 21 to the estimation model generation unit 14. The learning control unit 13 also compares the identification information of the odor substances corresponding to the change patterns input to the estimation model generation unit 14 with the estimation results output from the estimation model generation unit 14, and outputs a correction instruction to the estimation model generation unit 14 according to the comparison result.

[0155] The estimation model generation unit 14 generates an estimation model 22 using a machine learning algorithm that utilizes the change patterns stored in the change pattern database 21. The estimation model generation unit 14 may also be configured to generate the estimation model 22 using a known supervised machine learning algorithm. Examples of machine learning algorithms applicable to the estimation model generation unit 14 include the k-nearest neighbor method, logistic regression, support vector machines, random forests, and neural networks.

[0156] (Process to generate estimated model 22) The process of generating an estimation model 22 using the odor measuring device 100 will be explained below with reference to Figure 9. Figure 9 is a flowchart showing an example of the process flow in which the estimation device 10 of the odor measuring device 100 generates an estimation model 22. The estimation model 22 is generated by machine learning using training data that includes a combination of measured values ​​measured by the voltmeter 33 when each of a plurality of odor substances is adsorbed onto at least one sensor element, and identification information unique to the odor substance to which the measured value was given. Here, the identification information unique to the odor substance may be, for example, the name of the odor substance, the CAS number, and the chemical formula.

[0157] First, the measurement value acquisition unit 11 acquires the voltage value V0 measured by the odor sensor 30 before introducing the odor substance into the target sample receiving unit 50, and calculates the resistance value R0. The resistance value R0 is preferably 200 to 1000 Ω, more preferably 250 to 900 Ω, and most preferably 300 to 800 Ω. Then, the odor substance is placed into the target sample receiving unit 50 (step S1).

[0158] Meanwhile, the input unit 15 receives input such as the name of a known odor substance introduced into the target sample receiving unit 50 (step S2). The processing in step S2 may be performed before step S1.

[0159] Next, the measurement value acquisition unit 11 acquires data (waveform or time-dependent change pattern) of the change in voltage value V (ΔV) before and after the process of adsorption and desorption of odor substances to the sensor element 31 (step S3).

[0160] Next, the change pattern analysis unit 12 associates the change in voltage value V (ΔV) data (waveform or time-dependent change pattern) during the processes before and after adsorption and desorption of odor substances with the names of known odor substances that have been input and stores them in the change pattern database (step S4).

[0161] If no change patterns are stored for a given type of existing odor substance (NO in step S5), that is, if there is still insufficient data to use for machine learning, the process returns to step S1.

[0162] If change patterns for a predetermined type of existing odor substance are stored (YES in step S5), the learning control unit 13 reads the change patterns for known odor substances stored in the change pattern database 21 and inputs them to the estimation model generation unit 14. The estimation model generation unit 14 generates an estimation model 22 by machine learning based on the time-series change patterns (or features extracted from the change patterns) stored in the change pattern database 21 (step S6).

[0163] The estimation model generation unit 14 stores the estimation model 22 generated by predetermined machine learning in the storage unit 2 (step S7).

[0164] In the examples shown in Figures 8 and 9, the estimation device 10 generates the estimation model 22, but this is not limited to this. For example, an external computer different from the estimation device 10, which has the same functions as the learning control unit 13 and the estimation model generation unit 14, may be provided with the same data as the change pattern database 21 to create the estimation model 22.

[0165] <Estimation of odor molecules> Next, the configuration of the odor measuring device 100a, which estimates odor substances using the estimation model 22, and the estimation process will be explained using Figures 10 and 11.

[0166] (Configuration of estimation device 10a (Execution of estimation process)) Figure 10 is a functional block diagram showing an example of the configuration of the odor measuring device 100a. For the sake of clarity, components having the same function as those described in Figures 1, 4, and 8 are denoted by the same reference numerals, and their descriptions are not repeated.

[0167] As shown in Figure 10, the estimation device 10a comprises a control unit 1a, a storage unit 2a, and an output unit 18. Here, Figure 10 shows an example configuration when the estimation device 10 shown in Figure 8 is used for odor substance estimation processing. In other words, the estimation device 10 shown in Figure 8 and the estimation device 10a shown in Figure 10 may be computers with the same hardware configuration.

[0168] The output unit 18 is for presenting the estimation results to the user and may be, for example, a display, speaker, lamp, etc.

[0169] The control unit 1a includes a measurement value acquisition unit 11 (acquisition unit), a change pattern analysis unit 12 (analysis unit), an estimation unit 16, and an output control unit 17.

[0170] The estimation unit 16 uses the estimation model 22 to estimate odor substances from the analysis results obtained by analyzing the measured values ​​acquired from the odor sensor 30.

[0171] The output control unit 17 controls the output unit 18 to output the estimation result.

[0172] (Estimation process) The specific processes performed by each part of the control unit 1a will be explained below using Figure 11. Figure 11 is a flowchart showing an example of the process flow in which the estimation device 10a estimates odor substances.

[0173] First, the measurement value acquisition unit 11 acquires the voltage value V0 measured by the odor sensor 30 before introducing the odor substance into the target sample receiving unit 50, and calculates the resistance value R0. Then, an unknown odor substance (regardless of its properties) is introduced into the target sample receiving unit 50 (step S11).

[0174] Next, the measurement value acquisition unit 11 acquires data (waveform or time-dependent change pattern) of the change in voltage value V (ΔV) before and after the adsorption and desorption of the unknown (i.e., the odor substance to be estimated) onto the sensor element 31 (step S12).

[0175] Next, the estimation unit 16 estimates unknown odor substances based on the estimation model 22, using the time-series change pattern (or features extracted from the change pattern) (step S13).

[0176] The output control unit 17 controls the output unit to output the estimation result (step S14).

[0177] In the embodiments described above, an estimation device 10 that generates an estimation model 22 and an estimation device 10a that estimates odor substances using the estimation model 22 were described. Note that the estimation device 10 and the estimation device 10a may be separate devices or may be a single device.

[0178] <Example configuration of sensor element 31c> The following describes an example of the configuration of one sensor element 31c included in the sensor element group 31A, using Figures 12 to 20. In Figures 12 to 20, the dotted and shaded areas represent the odor substance receiving layers 315c to 315j. In one sensor element 31c included in the sensor element group 31A, the surface roughness (Sa) of the odor substance receiving layers 315c to 315j between opposing electrodes is 0.5 μm or more and 5 μm or less, more preferably 0.5 μm or more and 3 μm or less. In Figures 12 to 20, the shaded areas represent the regions of the odor substance receiving layers 315c to 315j where the surface roughness is measured. In the following description, if the odor substance receiving layers 315c to 315j are not distinguished, they will be collectively referred to as "odor substance receiving layer 315".

[0179] Figure 12 is a top view showing an example of the configuration of one sensor element 31c included in the sensor element group 31A. The sensor element 31c comprises an electrode 313 (first metal wiring 313C, second metal wiring 313D) arranged on a substrate 311, and a circular odor substance receiving layer 315c formed on the electrode 313. As shown in Figure 12, the first metal wiring 313C and the second metal wiring 313D are arranged in parallel lines. Specifically, the first metal wiring 313C comprises metal wiring 313a and metal wiring 313b arranged in a T-shape perpendicular to each other. The second metal wiring 313D comprises metal wiring 313c and metal wiring 313d arranged in a T-shape perpendicular to each other. Furthermore, metal wiring 313a and metal wiring 313c are arranged to be parallel to each other. The diameter R of the odor substance receiving layer 315c is 0.2 mm or more and 5 mm or less. In Figure 12, the shape of the odor substance receiving layer 315c of the sensor element 31c is elliptical as an example, but is not limited to this. When the shape of the odor substance receiving layer 315c is elliptical, the average of the minor axis and the major axis may be 0.2 mm or more and 5 mm or less. The shape of the odor substance receiving layer 315c may also be a perfect circle.

[0180] Figure 13 is a top view showing an example of the configuration of one sensor element 31d included in the sensor element group 31A. The sensor element 31d comprises an electrode 313 (first metal wiring 313C, second metal wiring 313D) arranged on a substrate 311, and a strip-shaped odor substance receiving layer 315d formed on the electrode 313. The length of the width of the odor substance receiving layer 315d in the short direction is 0.2 mm or more and 5 mm or less.

[0181] Figure 14 is a perspective view showing an example of the configuration of one sensor element 31c included in the sensor element group 31A. As shown in Figure 14, in the sensor element 31c, the first metal wiring 313C and the second metal wiring 313D are connected to pins 316 at the ends where they do not face each other. Pins 316 are conductive members for electrically connecting the first metal wiring 313C and the second metal wiring 313D to other components of the odor sensor 30. Although not shown, the sensor elements 31c and 31d shown in Figures 12 and 13 also have pins 316 as shown in Figure 14.

[0182] Figure 15 is a top view showing an example of the configuration of one sensor element 31i included in the sensor element group 31A. The sensor element 31i comprises an electrode 313 (first metal wiring 313C, second metal wiring 313D) arranged on a substrate 311, and a circular odor substance receiving layer 315i formed on the electrode 313. As shown in Figure 15, the first metal wiring 313C of the sensor element 31i has an annular metal wiring 313b and a metal wiring 313a connected to the metal wiring 313b. The second metal wiring 313D has an annular metal wiring 313c and a metal wiring 313d connected to the metal wiring 313c. The metal wiring 313d is connected to the metal wiring 313c via the back surface of the substrate 311. Furthermore, the metal wiring 313b and the metal wiring 313c are arranged concentrically on the substrate 311. The shape of the odor substance receiving layer 315i of the sensor element 31i is, for example, elliptical, but is not limited to this, and may be, for example, a perfect circle.

[0183] Figure 16 is a top view showing an example of the configuration of one sensor element 31f included in the sensor element group 31A. The sensor element 31j comprises an electrode 313 (first metal wiring 313C, second metal wiring 313D) arranged on a substrate 311, and a circular odor substance receiving layer 315j formed on the electrode 313. As shown in Figure 16, the first metal wiring 313C of the sensor element 31j has a comb-shaped metal wiring 313b and a metal wiring 313a connected to the metal wiring 313b. The second metal wiring 313D has a comb-shaped metal wiring 313c and a metal wiring 313d connected to the metal wiring 313c. Furthermore, the metal wiring 313b and the metal wiring 313c are arranged such that the protrusions of the metal wiring 313b face the recesses of the metal wiring 313c, and the protrusions of the metal wiring 313c face the recesses of the metal wiring 313b. The shape of the odor substance receiving layer 315j of the sensor element 31j is, for example, elliptical, but is not limited to this, and may be, for example, a perfect circle.

[0184] Figure 17 is a top view showing an example of the configuration of one sensor element 31k included in the sensor element group 31A. The sensor element 31k comprises electrodes 313 (first metal wiring 313C, second metal wiring 313D) arranged on a substrate 311, and a circular odor substance receiving layer 315k formed on the electrodes 313. As shown in Figure 17, the electrodes 313 of the sensor element 31k are arranged in a parallel curve. Specifically, the first metal wiring 313C of the sensor element 31k has a ring-shaped metal wiring 313b with a notch in part, and a metal wiring 313a connected from the notch to the metal wiring 313b. The second metal wiring 313D has a ring-shaped metal wiring 313c with a notch in part, and a metal wiring 313d connected from the notch to the metal wiring 313c. Furthermore, the metal wiring 313b and the metal wiring 313c are arranged concentrically. The shape of the odor substance receiving layer 315k of the sensor element 31k is, for example, elliptical, but is not limited to this, and may be, for example, a perfect circle.

[0185] Figure 18 is a top view showing an example of the configuration of one sensor element 31l included in the sensor element group 31A. The sensor element 31l comprises electrodes 313 (first metal wiring 313C, second metal wiring 313D) arranged on a substrate 311, and a circular odor substance receiving layer 315l formed on the electrodes 313. As shown in Figure 18, the electrodes 313 of the sensor element 31l are arranged in a straight line. Specifically, the first metal wiring 313C of the sensor element 31l has a straight metal wiring 313b and a metal wiring 313a connected to the metal wiring 313b. The second metal wiring 313D has a straight metal wiring 313c and a metal wiring 313d connected to the metal wiring 313c. Furthermore, the metal wiring 313b and the metal wiring 313c are arranged to be in a straight line. The shape of the odor substance receiving layer 315l of the sensor element 31l is, for example, elliptical, but is not limited to this, and may be, for example, a perfect circle.

[0186] Figure 19 is a top view showing an example of the configuration of one sensor element 31m included in the sensor element group 31A. The sensor element 31m comprises electrodes 313 (first metal wiring 313C, second metal wiring 313D) arranged on a substrate 311, and a circular odor substance receiving layer 315m formed on the electrodes 313. As shown in Figure 19, the electrodes 313 of the sensor element 31m are arranged in a counter-circular pattern. Specifically, the first metal wiring 313C of the sensor element 31m has a circular metal wiring 313b and a metal wiring 313a that connects to the metal wiring 313b from the back side of the substrate 311. The second metal wiring 313D has a circular metal wiring 313c and a metal wiring 313d that connects to the metal wiring 313c from the back side of the substrate 311. Furthermore, the metal wirings 313b and 313c are arranged to face each other on the substrate 311. The shape of the odor substance receiving layer 315m of the sensor element 31m is, for example, elliptical, but is not limited to this, and may be, for example, a perfect circle.

[0187] Figure 20 is a top view showing an example of the configuration of one sensor element 31n included in the sensor element group 31A. The sensor element 31n comprises electrodes 313 (first metal wiring 313C, second metal wiring 313D) arranged on a substrate 311, and a circular odor substance receiving layer 315n formed on the electrodes 313. The electrodes 313 of the sensor element 31n are arranged in parallel lines. As shown in Figure 20, in the sensor element 31n, the first metal wiring 313C and the second metal wiring 313D constituting the electrodes 313 may be arranged to be within the range of the odor substance receiving layer 315n. The shape of the odor substance receiving layer 315n of the sensor element 31n is elliptical as an example, but is not limited to this, and may be a perfect circle, for example.

[0188] By having the above configuration, instability in the output of the measurement result, which may be caused by variations in the shape and area of ​​the odor substance receiving layer 315 of each sensor element, is reduced, and the odor measuring device 100c can measure odor substances with high accuracy.

[0189] The sensor element group 31A may include multiple sensor elements other than sensor elements 31a to 31n. In Figure 5, the sensor element group 31A consists of 16 sensor elements 31 as an example, but the number of sensor elements 31 is not limited to this.

[0190] The odor substance receiving layers 315 provided by the multiple sensor elements 31A included in the sensor element group 31A may each contain a conductive carbon material and a resin composition. Furthermore, the odor substance receiving layers 315 may also contain a surfactant.

[0191] The odor substance receiving layers 315 of the multiple sensor elements 31A included in the sensor element group 31A may have different content ratios of conductive carbon material and resin composition. When the content ratios of conductive carbon material and resin composition in the odor substance receiving layer 315 differ, the sensitivity and detection specificity of the sensor element 31 to odor substances will also differ.

[0192] As described above, the odor measuring device 100 can detect a wide variety of odor substances by having multiple sensor elements 31, each equipped with an odor substance receiving layer 315 having a different content ratio of conductive carbon material and resin composition.

[0193] The thickness of the odor substance receiving layer 315 of the sensor element 31 included in the odor measuring device 100 according to this embodiment may be 0.1 μm or more and 100 μm or less. Furthermore, the thickness of each odor substance receiving layer 315 is preferably 3 μm or more and 100 μm or less. The thickness of each odor substance receiving layer 315 can be evaluated, for example, using a laser microscope (Keyence Corporation: "VK-8700").

[0194] Because the thickness of the odor substance receiving layer 315 of the sensor element 31 is within the aforementioned range, instability in the output of the measurement result that may be caused by variations in the thickness of the odor substance receiving layer 315 of each sensor element 31 is reduced, and the odor measuring device 100 can measure odor substances with high accuracy.

[0195] If the thickness of the odor substance receiving layer 315 is less than 0.1 μm, it will be close to the particle size of the conductive carbon material dispersed within the odor substance receiving layer 315, making it difficult to guarantee the uniformity of the thickness of the odor substance receiving layer 315, and potentially preventing the odor measuring device 100 from outputting stable measurement results. On the other hand, if the thickness of the odor substance receiving layer 315 is greater than 100 μm, the diffusion time of odor substances within the odor substance receiving layer 315 will be longer, making it difficult for the odor measuring device 100 to measure odor substances with high accuracy.

[0196] Because the thickness of the odor substance receiving layer 315 of the sensor element 31 is within the aforementioned range, instability in the output of the measurement result that may be caused by variations in the thickness of the odor substance receiving layer 315 of each sensor element 31 is reduced, and the odor measuring device 100 can measure odor substances with high accuracy.

[0197] The electrodes 313 of the sensor element 31 included in the sensor element group 31A each have a first metal wiring 313C and a second metal wiring 313D, and the first metal wiring 313C and the second metal wiring 313D may be arranged in a parallel linear shape, a parallel curve shape, a comb shape, or a concentric circular shape. In any of the shapes used, it is preferable that the first metal wiring 313C and the second metal wiring 313D are arranged symmetrically with respect to a line or point. By arranging the first metal wiring 313C and the second metal wiring 313D in this way, the odor measuring device 100 can measure odor substances contained in a gas with high accuracy.

[0198] The sensor element 31c in Figure 12 has a first metal wiring 313C and a second metal wiring 313D. For example, the first metal wiring 313C is composed of metal wiring 313a and metal wiring 313b, and the two metal wirings are arranged in a T-shape so that they are perpendicular to each other. The second metal wiring 313B is also composed of two metal wirings 313c and 313d, similar to the first metal wiring 313C, and is configured so that the two metal wirings are arranged in a T-shape so that they are perpendicular to each other. Furthermore, the first metal wiring 313C and the second metal wiring 313D are arranged in parallel lines so that metal wiring 313a and metal wiring 313c face each other.

[0199] In particular, the arrangement of the first metal wiring 313C and the second metal wiring 313D in a T-shape allows them to be placed at a suitable distance from each other, thereby stabilizing the resistance value of the electrodes. For example, if the electrodes are arranged in a comb shape, the distance between the electrodes becomes short, and there is a risk that the resistance value of the electrodes will become too low. Furthermore, because the first metal wiring 313C and the second metal wiring 313D are arranged in a T-shape, in the coating step of the sensor element manufacturing method described later, there are no uneven parts of the electrodes that could hinder the wetting and spreading of the slurry in the area where the slurry spreads, making it easier for the slurry to spread. In addition, because the slurry spreads more easily, there is an effect that the thickness of the odor substance receiving layer 315 after drying becomes constant.

[0200] <Manufacturing method for sensor elements> This document describes a manufacturing method for producing multiple types of sensor elements 31A used in the odor measuring device 100. The odor substance receiving layer 315 of the sensor element 31 can use slurries with various compositions as its raw material.

[0201] According to the manufacturing method of this embodiment, multiple types of sensor elements can be manufactured with minimal variation in shape, area, and thickness, even when using slurries of different compositions. Furthermore, since there is no need to change the manufacturing method depending on the slurry composition, manufacturing costs can be reduced.

[0202] Figure 21 is a flowchart illustrating the manufacturing process for producing multiple types of sensor elements 31A used in the odor measuring device 100.

[0203] (Slurry preparation process) First, several types of slurries with different mixing ratios of conductive carbon material and resin composition are prepared. The mixing ratio of the conductive carbon material and resin composition can be appropriately set according to the desired sensitivity and detection specificity of the odor substance receiving layer 315. In addition to the conductive carbon material and resin composition, the slurry may also contain a solvent, additives, and surfactants (S21).

[0204] (Electrode placement process) Next, electrodes are placed on the substrate (S22). The electrodes may consist of a first electrode and a second electrode. The first and second electrodes may be arranged in parallel lines, parallel curves, a comb shape, and concentric circles. Furthermore, in any of the shapes used, it is preferable that the first and second electrodes are arranged symmetrically with respect to a line or point. It is even more preferable that the first and second electrodes are arranged in parallel lines or parallel curves. It is particularly preferable that the first and second electrodes are arranged in the shapes shown in Figures 12 and 13. Specifically, the first electrode, the first metal wiring 313C, is composed of two metal wirings (313a and metal wiring 313c) arranged in a T-shape perpendicular to each other, and the second electrode, the second metal wiring 313D, is composed of two metal wirings (313c and metal wiring 313d) arranged in a T-shape perpendicular to each other. Preferably, the first metal wiring 313C and the second metal wiring 313D are arranged in parallel lines such that metal wiring 313a and metal wiring 313c face each other. With the first and second metal wirings arranged in this way, the odor measuring device 100 can measure odor substances contained in a gas with high accuracy.

[0205] As an example, in Figures 12 and 13, one set of electrodes 313 (first metal wiring 313C and second metal wiring 313D) is arranged on one substrate 311, but multiple sets of electrodes 313 may be arranged side by side on one substrate 311.

[0206] (Area definition process) Next, coating areas are defined on the substrate on which the electrodes are placed, for each of several types of slurries to be applied (S23). The coating areas may be defined, for example, by the placement of a resist. Also, if the slurry is dropped from a nozzle during the coating process, the coating areas may be defined according to the nozzle diameter. Figure 22 is a schematic diagram of the substrate 311 after the resist M has been placed. The resist M is placed to define the coating area 330. The coating area 330 is the substrate 311 in an exposed state.

[0207] The area of ​​the coating region 330 may be specified to be the same for each of the multiple types of slurries. That is, even if the slurries have different mixing ratios of conductive carbon material and resin composition, the area of ​​the coating region 330 for applying the slurry may be uniform. This reduces the variation in the area of ​​the multiple types of odor substance receiving layers 315 after drying, even when using multiple types of slurries with different mixing ratios.

[0208] The coated area 330 in Figure 22 is circular as an example, but the shape of the coated area 330 is not limited to this. The shape of the coated area 330 may be circular or strip-shaped. This forms a circular or strip-shaped odor substance receiving layer 315.

[0209] If the coated area 330 is circular, the diameter of the circle may be 0.2 mm or more and 5 mm or less. If the coated area 330 is strip-shaped, the length of the strip in the short direction may be 0.2 mm or more and 5 mm or less. This results in the formation of a circular odor substance receiving layer 315 with a diameter of 0.2 mm or more and 5 mm or less, and a circular odor substance receiving layer 315 with a length of 0.2 mm or more and 5 mm or less in the short direction.

[0210] The method for applying resist M is not particularly limited, but examples include silk-screen printing of solder resist onto a defined area and then UV curing of the solder resist, attaching a resist film to a substrate, and curing only the resist in a defined area and removing the uncured portion.

[0211] (Coating process) Next, each of the multiple types of slurry is applied to the application area 330 (S24). Conventional methods can be applied to the slurry, and it may be dispensed by dropping from a nozzle, spraying, or spin coating. The method of applying the slurry by dropping from a nozzle is particularly preferred, and for example, by using a SUS metal needle nozzle (inner diameter 0.1 mmΦ, outer diameter 0.23 mm) with the IMAGE MASTER350PCSmart manufactured by Musashi Engineering Co., Ltd., the desired application shape can be obtained.

[0212] (drying process) Finally, the slurry applied to the coating area 330 is dried to form the odor substance receiving layer 315 (S25). The method for drying the slurry is not particularly limited, but for example, a method of heating at 100°C for 1 hour at atmospheric pressure, and then heating at 100°C for 1 hour under reduced pressure in a vacuum dryer can be employed.

[0213] In the drying process, the thickness of the odor substance receiving layer 315 after drying may be between 0.1 μm and 100 μm. Preferably, the thickness of the odor substance receiving layer 315 after drying may be between 3 μm and 100 μm. If the thickness of the odor substance receiving layer 315 is within the above range, the sensor element 31 can stably measure odor substances. If the thickness of the odor substance receiving layer 315 is less than 0.1 μm, it will be close to the particle size of the conductive carbon material dispersed within the odor substance receiving layer 315, so the uniformity of the thickness of the odor substance receiving layer 315 cannot be guaranteed, and there is a risk that the odor measuring device 100 will not be able to output stable measurement results. On the other hand, if the thickness of the odor substance receiving layer 315 is greater than 100 μm, the diffusion time of odor substances within the odor substance receiving layer 315 will be longer, making it difficult for the odor measuring device 100 to measure odor substances with high accuracy.

[0214] As described above, the manufacturing method according to this embodiment includes a slurry preparation step, an electrode placement step, a region definition step, a coating step, and a drying step. By employing such a manufacturing method, multiple types of sensor elements 31 can be manufactured with minimal variation in the shape, area, and thickness of the odor substance receiving layer 315, even when using multiple types of slurries with different mixing ratios of conductive carbon material and resin composition. Furthermore, since there is no need to change the manufacturing method according to the slurry composition, manufacturing costs can be reduced.

[0215] In particular, defining the coating area during the area definition process improves the wetting and spreading of slurry droplets in subsequent coating processes. For example, when the coating area is defined with resist, the surface roughness differs between the areas of the substrate where resist is present and those where it is not. In areas where resist is absent, the substrate is exposed, resulting in higher surface roughness and lower surface tension. This improves the wetting and spreading of slurry droplets in the coating area where the substrate is exposed.

[0216] Furthermore, in the region definition process, the placement of the coating region restricts the wetting spread of the slurry in the subsequent coating process, and the positional relationship between the odor substance receiving layer 315 and the electrode becomes constant. For example, if the coating region is defined with resist, a step is created at the boundary of the resist, which restricts the wetting spread of the slurry, and the positional relationship between the odor substance receiving layer 315 and the electrode becomes constant.

[0217] [Variation] Figure 1 shows a configuration in which the first and second gases exiting from the sample receiving section 50 pass through the tube 93 and the sensor chamber 60, but the device is not limited to this configuration. Since the sample receiving section 50 of the odor measuring device 100 has a larger volume than the sensor chamber 60, it is not necessary to send the entire volume of the first gas inside the sample receiving section 50 to the sensor chamber 60 during measurement. Also, when purging the inside of the sample receiving section 50 with the second gas after measurement, it is not necessary for the sample receiving section 50 and the sensor chamber 60 to be connected. Therefore, the odor measuring device 100 may be configured to have a valve (not shown) on the tube 93 so that the first and second gases exiting from the sample receiving section 50 can be exhausted without passing through the sensor chamber 60.

[0218] <Examples of implementation using software> The control blocks (especially the control unit 1) of the estimation devices 10 and 10a may be implemented by logic circuits (hardware) formed on an integrated circuit (IC chip) or by software.

[0219] In the latter case, the estimation devices 10 and 10a are equipped with a computer that executes instructions for a program, which is software that realizes each function. This computer is equipped with, for example, one or more processors and a computer-readable recording medium that stores the program. The object of the present invention is achieved when the processor reads the program from the recording medium and executes it in the computer. For example, a CPU (Central Processing Unit) can be used as the processor. As the recording medium, a "tangible medium that is not temporary," such as ROM (Read Only Memory), can be used, as well as tape, disk, card, semiconductor memory, programmable logic circuit, etc. It may also be further equipped with RAM (Random Access Memory) for expanding the program. Furthermore, the program may be supplied to the computer via any transmission medium capable of transmitting the program (such as a communication network or broadcast wave). In one aspect of the present invention, the program can also be realized in the form of a data signal embedded in a carrier wave, which is embodied by electronic transmission.

[0220] 〔summary〕 A method for manufacturing a plurality of sensor elements according to Embodiment 1 of the present disclosure includes a slurry preparation step of preparing a plurality of types of slurries comprising a conductive carbon material, a resin composition, and a surfactant, wherein the mixing ratios of the conductive carbon material, the resin composition, and the surfactant are different; an electrode placement step of arranging electrodes 313 on a substrate 311; a region defining step of defining a coating region 330 on the substrate on which the electrodes 313 are arranged, to which each of the plurality of slurries is applied; a coating step of applying each of the plurality of slurries to the coating region 330; and a drying step of drying the slurry applied to the coating region 330 to form an odor substance receiving layer, wherein the area of ​​the coating region is 0.0003 square centimeters or more and 0.2 square centimeters or less.

[0221] In the manufacturing method according to aspect 2 of this disclosure, in aspect 1, the surface roughness (Sa) of the odor substance receiving layer between the opposing electrodes may be 0.5 μm or more and 5 μm or less.

[0222] In the manufacturing method according to Embodiment 3 of the present disclosure, in either Embodiment 1 or 2, the shape of the coating area 330 is circular or strip-shaped, and if the shape of the coating area 330 is circular, the diameter of the circle is 0.2 mm or more and 5 mm or less, and if the shape of the coating area 330 is strip-shaped, the length of the strip in the short direction is 0.2 mm or more and 5 mm or less.

[0223] In the manufacturing method according to aspect 4 of this disclosure, in any of aspects 1 to 3, the thickness of the odor substance receiving layer after drying may be 0.1 μm or more and 100 μm or less in the step of forming the odor substance receiving layer.

[0224] In the manufacturing method according to aspect 5 of the present disclosure, in any of aspects 1 to 4, the first electrode 313C and the second electrode 313D may be arranged in a parallel straight line, a parallel curve, a comb shape, or concentric circles in the step of arranging them.

[0225] A sensor element according to embodiment 6 of the present disclosure comprises an electrode disposed on a substrate and an odor substance receiving layer formed on the electrode, wherein the odor substance receiving layer comprises a conductive carbon material and a resin composition, and is formed by applying each of several types of slurries with different mixing ratios of the conductive carbon material and the resin composition to a coating area on the substrate on which the electrode is disposed, and drying the applied slurries, the area of ​​which is 0.0003 square centimeters or more and 0.2 square centimeters or less.

[0226] In the sensor element according to embodiment 7 of this disclosure, the thickness of the odor substance receiving layer is 0.1 μm or more and 100 μm or less, as described in embodiment 6.

[0227] An odor measuring device according to embodiment 8 of the present disclosure comprises a plurality of sensor elements as described in embodiment 6 or 7, each of which comprises an odor substance receiving layer having different content ratios of conductive carbon material, resin composition, and surfactant. [Examples]

[0228] The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited thereto. Unless otherwise specified, % refers to weight percent and parts refers to parts by weight.

[0229] The following describes the various materials used in the examples and comparative examples.

[0230] <Resin (A)> A1: Polyamide resin (manufactured based on manufacturing example 1 described below) <Surfactant (B)> B1: Carbon black dispersant (Disparon DA-325, manufactured by Kusumoto Kasei Co., Ltd.) <Conductive carbon material (C)> C1: Carbon Black (SuperC65, manufactured by MTI Corporation) <Solvent (D)> D1: N-methyl-2-pyrrolidone An example of resin (A) production is shown.

[0231] Manufacturing example (Manufacturing of polyester resin P1) In a reaction vessel equipped with a stirrer, thermometer, heating / cooling device, nitrogen inlet tube, reflux tube, dehydration tube with stopcock, and vacuum device, 20 parts xylene, 220 parts 12-hydroxystearic acid, and 10 parts adipic acid were added. After purging with nitrogen, the mixture was sealed and heated to 160°C while stirring. After stirring at this temperature for 4 hours, stirring was continued for another 4 hours while removing the water produced by the reaction under reduced pressure using the vacuum device. At this time, the xylene in the dilute was separated from the produced water and returned to the reaction vessel. This yielded a xylene solution (solid content concentration 91%) of polyester resin P1 with an acid value of 33 mg KOH / g and a weight-average molecular weight of 3,300.

[0232] Examples of resin compositions are shown below.

[0233] <Resin composition 1> The following components were weighed into sample bottles in the amounts specified below to obtain a mixture.

[0234] Resin A1 (polyamide resin) 80 parts by weight Conductive carbon material C1: 20 parts by weight Solvent D1 400 parts by weight The mixture was stirred at 2000 revolutions per minute for 20 minutes using a rotation / revolution mixer (ARE-310, manufactured by Thinky Co., Ltd.) to obtain a slurry. Thus, resin composition 1 was obtained as the slurry.

[0235] The following shows examples and comparative examples of sensor elements.

[0236] <Manufacturing of sensor substrate K-1> [Manufacturing of circuit boards] In this embodiment, a glass cloth-based epoxy resin copper-clad laminate board FR-4.0 (manufactured by Panasonic Electric Works Co., Ltd.) measuring 150 mm in length, 100 mm in width, and 1.0 mm in thickness was used, and sensor substrates designed on this laminate board were manufactured in 16 rows vertically and 16 columns horizontally (a total of 256 units) using the method described later. At this time, margins of 11 mm each were secured at the top and bottom, and 10 mm each on the left and right sides.

[0237] [Wiring pattern design] A total of 256 wiring patterns were designed on the aforementioned laminate, with a substrate size of 8 mm vertically and 5 mm horizontally, in the shape of T-shaped electrodes facing each other as shown in Figure 12, with lengths of 313a and 313c of 2.5 mm, lengths of 313b and 313d of 2 mm, a spacing of 1.5 mm between 313a and 313c, and a width of 0.3 mm for each electrode. Furthermore, circular conductive parts with a diameter of 1 mm were provided at the ends of the first metal wiring 313C and the second metal wiring 313D that do not face each other, to serve as insertion points for conductive pins that electrically connect to other components of the odor sensor, and similar circular conductive parts with a diameter of 1 mm were designed at the same positions on the back side.

[0238] [Through-hole fabrication process] To mount pins on each sensor substrate, through-holes were drilled using an NC drilling machine in circular conductive areas with a diameter of 1 mm. First, electroless copper plating was applied, followed by copper sulfate plating to create through-holes with a copper plating layer 25 μm thick.

[0239] [Pattern formation process] A photosensitive dry film resist (product name "Photec RD-3025", film thickness 25 μm, manufactured by Showa Denko Materials Co., Ltd.) was applied to both sides of the sensor substrate using a roll laminator (pressure 0.4 MPa, temperature 110 °C, lamination speed 0.4 m / min). Subsequently, ultraviolet light (wavelength 355 nm) was applied at a rate of 85 mJ / cm² from the photosensitive dry film resist side through a negative photomask for the front and a negative photomask for the back using an ultraviolet exposure machine. 2 The photosensitive dry film resist in the unexposed areas was removed with a 5% by weight sodium carbonate aqueous solution at 35°C. Subsequently, the copper foil in the areas where the photosensitive dry film resist had been removed was etched off using a ferric chloride aqueous solution, and the photosensitive dry film resist in the exposed areas was removed using a 10% by weight sodium hydroxide aqueous solution at 35°C.

[0240] The negative photomask used for the front surface had a pattern in which the designed sensor substrate was arranged in 16 rows at 8mm intervals vertically and 16 columns at 5mm intervals horizontally. The negative photomask for the back surface had a pattern in which a 2mm diameter circle was placed in a position that coincided with the circular portion of the negative photomask for the front surface.

[0241] [Solder resist process] A two-component alkaline developable solder resist ink (manufactured by Taiyo Ink Mfg. Co., Ltd., product name "PSR-4000 AUS320 / CA-40 AUS320") was pattern-printed on the front side, excluding the copper foil portion, through-hole portion, and circular odor substance receiving layer 315c portion (shown by the shaded area in Figure 14), and on the back side, excluding the copper foil portion and through-hole portion. After pre-drying by heating at 80°C for 30 minutes, ultraviolet light (wavelength 355nm) at 600mJ / cm² was applied. 2 The surface was irradiated, and the unexposed areas were removed with a 1% by weight sodium carbonate aqueous solution at 35°C. The solder resist ink was then cured by heating at 150°C for 60 minutes.

[0242] [Surface treatment process] The sensor substrate was degreased, soft-etched, and acid-cleaned. It was then immersed in a catalyst solution (Okuno Pharmaceutical Co., Ltd., product name "ICP Accela COA") at 25°C for 5 minutes, rinsed with water, and immersed in an electroless nickel plating solution (Okuno Pharmaceutical Co., Ltd., product name "Top Nicolon SA-98-MLF" 100 ml and "Top Nicolon SA-98-1LF" 55 ml) at 90°C for 6 minutes to form a 3 μm thick nickel coating. After that, it was rinsed with pure water.

[0243] Next, the sensor substrate was immersed in a displacement gold plating solution (manufactured by Kojima Chemical Co., Ltd., product name "OL2300") at 85°C for 5 minutes to form a displacement gold film with a thickness of 0.05 μm on the Ni film, resulting in a substrate in which the copper foil portion was coated with nickel and gold plating.

[0244] [V-cut on circuit board] Using a V-cutting machine, V-cuts were made at intervals of 8mm vertically and 5mm horizontally so that each sensor substrate could be separated individually.

[0245] [Pin implementation] IC terminals (manufactured by Mac Eight Co., Ltd., product name "Hybrid IC Terminals", φ0.6mm, length 5mm) were soldered to the fabricated through-holes. A total of 256 sensor boards K-1 were manufactured using these methods.

[0246] This allowed us to fabricate the sensor substrate K-2.

[0247] <Sensor element> [Sensor element E1] Using an IMAGE MASTER350PCSmart manufactured by Musashi Engineering Co., Ltd., fitted with a stainless steel metal needle nozzle (inner diameter 0.1 mmΦ, outer diameter 0.23 mm), the resin composition was dropped onto the fabricated sensor substrate K-1, thereby coating the metal wiring portion. After coating, it was dried for 3 hours in a circulating air dryer heated to 100°C. After drying, it was cooled to room temperature to fabricate the sensor element E1. As an example, the diameter of the odor substance receiving layer 315c in sensor element E1 is 2 mm and its area is 0.031 cm². 2 As an example, the thickness of the odor substance receiving layer 315c in sensor element E1 is 5 μm. The same procedure was repeated 10 times, and 10 samples were fabricated for each sensor element. By fabricating in this manner, sensor element E1 has a circular odor substance receiving layer 315c as shown in Figure 12.

[0248] [Sensor element E2] Sensor element E2 according to Example 2 was fabricated in the same manner as sensor element E1, except that in the solder resist process, a two-component alkaline developable solder resist ink was pattern-printed on the portion excluding the strip-shaped odor substance receiving layer 315d (the portion shown by the diagonal lines in Figure 13). By fabricating as described above, sensor element E2 has a strip-shaped odor substance receiving layer 315d as shown in Figure 13.

[0249] [Sensor element E3] The area of ​​the final odor substance receiving layer 315 is 0.008 cm². 2 Except for the above, the sensor element E3 according to Example 3 was fabricated in the same manner as the sensor element E1.

[0250] [Sensor element E4] The area of ​​the final odor substance receiving layer 315 is 0.071 cm². 2A sensor element E4 according to Example 4 was produced in the same manner as the sensor element E1, except for the above.

[0251] [Sensor Element E5] The area of the final odorant receptive layer 315 is 0.0003 cm 2 A sensor element E5 according to Example 5 was produced in the same manner as the sensor element E1, except for the above.

[0252] [Sensor Element E6] The area of the final odorant receptive layer 315 is 0.196 cm 2 A sensor element E6 according to Example 6 was produced in the same manner as the sensor element E1, except for the above.

[0253] [Sensor Element E7] A sensor element E7 according to Example 7 was produced in the same manner as the sensor element E1, except that the thickness of the final odorant receptive layer 315 was set to 1 µm.

[0254] [Sensor Element E8] A sensor element E8 according to Example 8 was produced in the same manner as the sensor element E1, except that the thickness of the final odorant receptive layer 315 was set to 50 µm.

[0255] [Sensor Element E9] A sensor element E9 according to Example 9 was produced in the same manner as the sensor element E1, except that the thickness of the final odorant receptive layer 315 was set to 0.1 µm.

[0256] [Sensor Element E10] A sensor element E10 according to Example 10 was produced in the same manner as the sensor element E1, except that the thickness of the final odorant receptive layer 315 was set to 100 µm.

[0257] [Sensor Element E11] A sensor element E11 according to Example 11 was produced in the same manner as the sensor element E1, except that the first metal wiring 313C and the second metal wiring 313D were arranged in a parallel curved shape as shown in FIG. 17.

[0258] [Sensor element E12] Sensor element E12 according to Example 12 was fabricated in the same manner as sensor element E1, except that the first metal wiring 313C and the second metal wiring 313D were arranged in a comb-like shape as shown in Figure 16.

[0259] [Sensor element E13] The sensor element E13 according to Example 13 was fabricated in the same manner as the sensor element E1, except that the first metal wiring 313C and the second metal wiring 313D were arranged concentrically as shown in Figure 15.

[0260] [Sensor element E14] A sensor element E14 according to Comparative Example 1 was fabricated in the same manner as sensor element E1, except that the resin composition was applied to the exposed parts of the metal wiring on the fabricated sensor substrate K-1 using a bar coater (No. 4).

[0261] [Sensor element E15] Sensor element E15 according to Comparative Example 2 was fabricated in the same manner as sensor element E1, except that the solder resist process was omitted.

[0262] [Sensor element E16] A sensor element E16 according to Comparative Example 3 was fabricated in the same manner as sensor element E1, except that the pipetteman (nozzle) was coated with the resin composition onto the exposed portion of the metal wiring.

[0263] [Sensor element E17] A sensor element E17 according to Comparative Example 4 was fabricated in the same manner as sensor element E1, except that the shape of the odor substance receiving layer 315 was made square.

[0264] [Sensor element E18] The area of ​​the final odor substance receiving layer 315 is 0.0001 cm². 2 Aside from the above, the sensor element E18 according to Comparative Example 5 was fabricated in the same manner as sensor element E1.

[0265] [Sensor element E19] Set the area of the final odorant-receiving layer 315 to 0.035 cm 2 A sensor element E19 according to Comparative Example 6 was produced in the same manner as sensor element E1, except for the above setting.

[0266] [Sensor Element E20] A sensor element E20 according to Comparative Example 7 was produced in the same manner as sensor element E1, except that the thickness of the final odorant-receiving layer 315 was set to 0.05 μm.

[0267] [Sensor Element E21] A sensor element E21 according to Comparative Example 8 was produced in the same manner as sensor element E1, except that the thickness of the final odorant-receiving layer 315 was set to 150 μm.

[0268] <Construction of Odor Sensors 1 to 13 and c1 to c8> A housing was produced, which includes: a target sample receiving section provided with an inlet for introducing a specimen (odorant) and an aluminum block constant temperature bath for temperature adjustment; and a nitrogen gas cylinder for gas supply, a mass flow controller, and a sensor chamber. At this time, the volume of the target sample receiving section was designed to be 5 times the volume of the sensor chamber.

[0269] A lead wire for leading out the sensor terminal to the outside was soldered to the sensor element E1, and the sensor element E1 was placed inside the sensor chamber. For the sensor element E1, a 5 V constant-voltage power supply and a 300 Ω fixed resistor were connected in series to the end of the lead wire led out to the outside of the sensor chamber, and a voltmeter for measuring the voltage applied across both terminals of the sensor element was connected. Thus, the odor sensor 1 including the sensor element E1 was constructed.

[0270] Further, odor sensors 2 to 13 according to Examples 2 to 13 were constructed in the same manner as the odor sensor 1, except that sensor elements E2 to E13 were used. In addition, odor sensors c1 to c8 according to Comparative Examples 1 to 8 were constructed in the same manner as the odor sensor 1, except that sensor elements E14 to E21 were used.

[0271] [Measurement of coefficient of variation of resistance value] For each of the odor sensors 1-13 and c1-c8, which were installed in the laboratory (temperature 23°C, humidity 40%), the temperature inside the sample receiving section was controlled to 30°C using an aluminum block constant temperature bath. Then, 5 mL of melon juice was placed in the inlet of each odor sensor as a sample. Next, nitrogen gas was supplied from a nitrogen gas cylinder to the sample receiving section at a flow rate of 1 L / min for 5 seconds using a mass flow controller, and then discharged to the outside via the sensor chamber. Subsequently, without passing through the sample receiving section, nitrogen gas was supplied directly from the cylinder to the sensor chamber at a flow rate of 5 L / min for 60 seconds using a mass flow controller, and then discharged to the outside. This operation removed odor substances attached to the sensor elements. During this time, the readings from the voltmeter connected to the sensor elements were recorded by computer. In this way, the resistance values ​​of each of the four sensor elements in the odor sensor were measured. For each sensor element of each odor sensor, the maximum difference between the resistance value before sample introduction and the resistance value during sample introduction was calculated. This odor measurement operation was repeated 30 times. Then, the standard deviation σ and mean value μ of the maximum value data obtained for each sensor element were calculated, and the coefficient of variation (=σ / μ) of the resistance value of each sensor element was determined.

[0272] [Measurement of surface roughness (Sa)] For each of the created sensor elements E1 to E20, the surface roughness (Sa) of the odor substance receiving layer 315 was measured. Surface roughness was measured according to "ISO 25178".

[0273] For Examples 1-13 and Comparative Examples 1-8, the experimental resistance values ​​were measured, and the coefficient of variation of the resistance values ​​was evaluated. The configuration of each sensor element and the evaluation results are shown in Tables 1-3.

[0274] [Table 1]

[0275] [Table 2]

[0276] [Table 3]

[0277] If the coefficient of variation of the resistance value is 0.15 or less, preferably 0.10 or less, and more preferably 0.08 or less, then the variation in performance among multiple sensor elements in a single odor sensor is sufficiently small and can be judged as not posing any practical problems. From the viewpoint of reducing such variation, a smaller coefficient of variation of the resistance value is preferable.

[0278] In Tables 1-3, "◎" indicates that the performance variation among multiple sensor elements in a single odor sensor is remarkably small, and the performance of the odor sensor is particularly favorable for practical use; "○" indicates that the performance of the odor sensor is favorable for practical use; "△" indicates that the performance of the odor sensor is not problematic for practical use; and "×" indicates that the performance of the odor sensor is poor.

[0279] <Consideration> As shown in Tables 1 and 2, the odor sensors 1 to 13 (Examples 1 to 13) in the examples all had practically satisfactory or desirable performance. On the other hand, as shown in Table 3, the odor sensors c1 to c8 (Comparative Examples 1 to 8) in the comparative examples all had poor performance.

[0280] A comparison between Examples 1 and 2 revealed that if the odor substance receiving layer 315 of the sensor element is circular or strip-shaped, the odor sensor will have practically acceptable performance.

[0281] A comparison between Examples 1 and 3-6 shows that the area of ​​the odor substance receiving layer 315 of the sensor element is 0.0003 cm². 2 ~0.196cm 2 Within this range, the odor sensor was found to have practically acceptable performance. In particular, the area of ​​the odor substance receiving layer 315 was 0.008 cm². 2 ~0.071cm 2 It was found that configurations within this range are practically preferable to configurations with other area ranges.

[0282] A comparison between Examples 1 and 7-10 revealed that if the thickness of the odor substance receiving layer 315 of the sensor element is within the range of 0.1 μm to 100 μm, the odor sensor will have practically acceptable performance. In particular, a configuration in which the thickness of the odor substance receiving layer 315 is within the range of 1 μm to 50 μm was found to be practically preferable to configurations with other thicknesses.

[0283] A comparison between Examples 1 and 11-13 revealed that the odor sensor performs adequately for practical purposes if the first metal wiring 313C and the second metal wiring 313D are arranged in parallel lines, parallel curves, comb-like shapes, or concentric circles. In particular, the configuration in which the first metal wiring 313C and the second metal wiring 313D are arranged in parallel lines or parallel curves was found to be more practically preferable than the configuration in which they are arranged in comb-like shapes or concentric circles.

[0284] A comparison between Example 1 and Comparative Example 1 revealed that the quality of the odor substance receiving layer 315 was more stable and the performance variation between sensor elements was reduced in sensor element E1, which was coated using a coating machine, compared to sensor element E14, which was coated using a bar coater (No. 4). Thus, it was found that the odor sensor 1 of Example 1 is a more practically preferable configuration than the odor sensor c1 of Comparative Example 1.

[0285] A comparison between Example 1 and Comparative Example 2 revealed that the quality of the odor substance receiving layer 315 was more stable and the performance variation between sensor elements was reduced in sensor element E1, which had the odor substance receiving layer 315 formed with resist regulation, compared to sensor element E15, which had the odor substance receiving layer 315 formed without resist regulation. Thus, it was found that the odor sensor 1 of Example 1 is a more practically preferable configuration than the odor sensor c2 of Comparative Example 2.

[0286] A comparison between Example 1 and Comparative Example 3 revealed that the quality of the odor substance receiving layer 315 was more stable and the performance variation between sensor elements was reduced in sensor element E1, which was coated using a coating machine, compared to sensor element E16, which was coated using a pipetteman (nozzle). Thus, it was found that the odor sensor 1 of Example 1 is a more practically preferable configuration than the odor sensor c3 of Comparative Example 3.

[0287] A comparison of Examples 1 and 2 with Comparative Example 4 revealed that sensor elements E1 and E2, which have a circular or strip-shaped odor substance receiving layer 315, exhibit more stable quality of the odor substance receiving layer 315 and reduced performance variation between sensor elements compared to sensor element E17, which has a square-shaped odor substance receiving layer 315. This variation in performance is thought to be due to the fact that the sensor element E17 in Comparative Example 4 has a square-shaped odor substance receiving layer 315, and the slurry did not sufficiently reach the four corners. Thus, it was found that odor sensor 1 of Example 1 and odor sensor 2 of Example 2 are practically preferable configurations to odor sensor c4 of Comparative Example 4.

[0288] A comparison of Examples 1, 3, and 5 with Comparative Example 5 shows that the area of ​​the odor substance receiving layer 315 of the sensor element is 0.0003 cm². 2 The area of ​​the odor substance receiving layer 315 is 0.0003 cm², which is lower than the area of ​​the sensor element E18. 2 It was found that sensor elements E1, E3, and E5, having the above-mentioned area, exhibited more stable quality of the odor substance receiving layer 315 and reduced performance variation among sensor elements. Thus, it was found that odor sensors 1, 3, and 5 of Examples 1, 3, and 5 have a more practically preferable configuration than odor sensor c5 of Comparative Example 5.

[0289] A comparison of Examples 4 and 6 with Comparative Example 6 shows that the area of ​​the odor substance receiving layer 315 of the sensor element is 0.02 cm². 2 The area of ​​the odor substance receiving layer 315 is 0.02 cm² larger than that of the sensor element E19. 2It was found that sensor elements E4 and E6 with the following areas exhibited more stable quality of the odor substance receiving layer 315 and reduced performance variation between sensor elements. Thus, it was found that the odor sensor 4 of Example 4 and the odor sensor 6 of Example 6 have a more practically preferable configuration than the odor sensor c6 of Comparative Example 6.

[0290] A comparison of Examples 7 and 9 with Comparative Example 7 revealed that the odor substance receiving layer 315 thickness was more stable and the performance variation between sensor elements was reduced in sensor elements E7 and E9, which have an odor substance receiving layer 315 thickness of 0.1 μm or more, compared to sensor element E20, which has an odor substance receiving layer 315 thickness of less than 0.1 μm. Thus, it was found that the odor sensor 7 of Example 7 and the odor sensor 9 of Example 9 are practically preferable configurations to the odor sensor c7 of Comparative Example 7.

[0291] A comparison of Examples 8 and 10 with Comparative Example 8 revealed that the odor substance receiving layer 315 thickness was more stable and the performance variation between sensor elements was reduced in sensor elements E8 and E10, which have an odor substance receiving layer 315 thickness of 100 μm or less, compared to sensor element E21, which has an odor substance receiving layer 315 thickness of more than 100 μm. Thus, it was found that the odor sensor 8 of Example 8 and the odor sensor 10 of Example 10 have a more practically preferable configuration than the odor sensor c8 of Comparative Example 8.

[0292] As described above, it was found that an odor measuring device manufactured by a manufacturing method comprising a slurry preparation step of preparing multiple types of slurries containing a conductive carbon material and a resin composition, wherein the mixing ratio of the conductive carbon material and the resin composition differs; an electrode placement step of placing electrodes on a substrate; a region defining step of defining a coating area on the substrate on which the electrodes are placed, to which each of the multiple types of slurries is applied; a coating step of applying each of the multiple types of slurries to the coating area; and a drying step of drying the slurry applied to the coating area to form an odor substance receiving layer 315, wherein the area of ​​the coating area is 0.0003 square centimeters or more and 0.2 square centimeters or less, can perform repeated and stable measurements. [Industrial applicability]

[0293] The present invention is useful as an odor identification sensor for medical, gas detection, agricultural, and other industrial and daily life applications. For example, farmers can use the odor identification sensor to determine the maturity of fragrant crops and manage the optimal harvesting timing. Furthermore, the odor of products such as food or cosmetics can be digitized using the odor identification sensor to support improved efficiency in product development and stabilization of quality. [Explanation of Symbols]

[0294] 10, 10a Estimation device 11 Measurement value acquisition unit (acquisition unit) 12. Change Pattern Analysis Unit (Analysis Unit) 16 Estimation part 30, 30b Odor Sensor 31, 31b, 31c, 31d Sensor elements 32, 32b Constant voltage power supply (power supply) 33, 33b Voltmeter (measuring instrument) 100 Odor measuring device 313A, 313C 1st metal wiring 313B, 313D 2nd metal wiring 315, 315c~315n Odor substance receiving layer 313C 1st electrode 313D 2nd electrode 330 Application area

Claims

1. A method for manufacturing an odor measuring device comprising a plurality of sensor elements, The aforementioned multiple sensor elements are A slurry preparation step comprising preparing multiple types of slurries containing a conductive carbon material and a resin composition, wherein the mixing ratio of the conductive carbon material and the resin composition differs, An electrode placement step involves arranging a first electrode and a second electrode spaced apart from each other on a substrate, A region defining step to define a coating region on a substrate on which the first electrode and the second electrode are arranged, wherein one of the plurality of types of slurry is applied, and the applied slurry is in contact with at least a part of the first electrode and at least a part of the second electrode, and is defined to fill the area between the first electrode and the second electrode. A coating step of applying one of the above-mentioned plurality of types of slurry to the coating area defined on the substrate, The manufacturing method includes a drying step of drying the slurry applied to the coating area to form an odor substance receiving layer, The area of ​​the coating region is 0.0003 square centimeters or more and 0.2 square centimeters or less. Between the opposing first electrode and the second electrode, the surface roughness (Sa) of the odor substance receiving layer is 0.5 μm or more and 5 μm or less. A method for manufacturing an odor measuring device.

2. The shape of the coating area is circular or strip-shaped. If the shape of the coating area is circular, the diameter of the circle is 0.2 mm or more and 5 mm or less. The method for manufacturing an odor measuring device according to claim 1, wherein, when the shape of the coating area is strip-shaped, the length of the strip in the short direction is 0.2 mm or more and 5 mm or less.

3. The method for manufacturing an odor measuring device according to claim 1, wherein in the drying step, the thickness of the odor substance receiving layer formed after drying is 0.1 μm or more and 100 μm or less.

4. The method for manufacturing an odor measuring device according to claim 1, wherein in the electrode arrangement step, the first electrode and the second electrode are arranged in parallel straight lines, opposing circles, parallel curves, comb shape, or concentric circles.

5. A sensor comprising a plurality of sensor elements, each of the plurality of sensor elements having a first electrode and a second electrode arranged on a substrate and spaced apart from each other, The substrate comprises an odor substance receiving layer formed in a coated region that is in contact with at least a portion of the first electrode and at least a portion of the second electrode, and that fills the region sandwiched between the first electrode and the second electrode, The odor substance receiving layer is The conductive carbon material and resin composition are included. The substrate is formed by applying one of several types of slurries with different mixing ratios of the conductive carbon material and the resin composition to the coating area, and then drying the applied slurries. The area of ​​the coating region is 0.0003 square centimeters or more and 0.2 square centimeters or less. An odor measuring device wherein the surface roughness (Sa) of the odor substance receiving layer between the opposing first electrode and the second electrode is 0.5 μm or more and 5 μm or less.

6. The shape of the coating area is circular or strip-shaped, If the shape of the coating area is circular, the diameter of the circle is 0.2 mm or more and 5 mm or less. The odor measuring device according to claim 5, wherein, when the shape of the coating area is strip-shaped, the length of the strip in the short direction is 0.2 mm or more and 5 mm or less.

7. The odor measuring device according to claim 5, wherein the thickness of the odor substance receiving layer is 0.1 μm or more and 100 μm or less.

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