Resin composition for forming odorant-accepting layer, sensor element using same, odor sensor, and odor measuring device

Abstract

The present invention addresses the problem of providing a technology that can improve odor identification performance in odor measurement by an odor sensor without lowering the production stability of a resin composition. A resin composition according to an embodiment of the present invention solves the above problem by including polyvinyl acetal (A) and a filler (C), the filler (C) content being within a specific range, and by including a surfactant (B) within a specific range, or not including the surfactant (B).

Description

Resin composition for forming an odorant-receiving layer, sensor element using the same, odor sensor, and odor measuring device

[0001] The present invention relates to a resin composition for forming an odorant-receiving layer, and a sensor element, an odor sensor, and an odor measuring device using the same.

[0002] Recent advances in information processing technology have led to the prospect of quantifying olfaction, one of the five human senses that has yet to be fully measured mechanically. If olfaction could be quantified in some way, it could be used in a wide range of industrial fields. For example, in the medical field, applications include nursing care, assistance, preventive diagnosis, and disease testing. In the environmental field, applications include odor control in factories, fermentation process management in biogas utilization, and wastewater treatment management. In the safety field, applications include predictive detection of disasters such as landslides and floods, and deterioration detection of engine oil and machine oil. In the food industry, applications include detecting the maturation state of ingredients such as plants and meat, process management of fermented foods such as alcoholic beverages, plant cultivation management, and quality control during food production, storage, and distribution. Furthermore, in the marketing field, applications are expected in the production of cosmetics, body odor, fragrant environments, and commercial scents. To date, methods for detecting specific gaseous substances (environmental odor gases) have been achieved with high accuracy and sensitivity using semiconductor gas sensors.

[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 thermally decomposed and substances that do not undergo redox reactions on the surface of the sensor's detection unit.

[0004] Furthermore, Patent Document 2 focuses on the property that the electrical resistance of a mixture of an organic polymer and a conductive material changes when exposed to an organic gas. Patent Document 2 describes preparing multiple combinations of organic polymer / conductive material with different organic polymer compositions from the mixture and using these as an electrical resistance array in a sensor. It shows that when exposed to the same organic gas, the electrical resistance changes differently. Patent Document 2 reports that this can be used to identify odors by associating the pattern of electrical resistance changes with the type of odor (i.e., organic gas mixture).

[0005] Furthermore, Patent Document 3 reports that the response speed of the sensor can be improved by adding a plasticizer to the organic polymer.

[0006] Patent Documents 4 and 5 disclose odor measuring devices that use a resin composition containing a resin composition, a surfactant, and a conductive carbon material.

[0007] Japanese Patent Application Laid-Open No. 11-23508 Japanese Patent Application Laid-Open No. 11-503231 Japanese Patent Application Laid-Open No. 2002-519633 Japanese Patent Application Laid-Open No. 2024-008838 Japanese Patent Application Laid-Open No. 2024-12146

[0008] The odorant receiving layer of an odor sensor contains a resin composition. This resin composition generally contains a resin, a dispersant, and a filler. Of these components, the dispersant is primarily used to disperse the resin. However, the higher the dispersant content in the resin composition, the lower the odor discrimination performance when the resin composition is used in an odor sensor. On the other hand, a low dispersant content also presents the problem of reduced manufacturing stability of the resin composition.

[0009] One aspect of the present invention has been made in consideration of the above-mentioned problems, and aims to provide a technology that can improve the odor discrimination performance in odor measurement using an odor sensor without reducing the manufacturing stability of the resin composition.

[0010] The present inventors have conducted research to achieve the above object and have arrived at the present invention.

[0011] That is, the resin composition for an odorant receiving layer in one embodiment of the present invention contains at least polyvinyl acetal (A) and filler (C), and the content of the filler (C) is 40 to 85% by weight relative to 100% by weight of the total of the polyvinyl acetal (A) and filler (C), and if the resin composition further contains surfactant (B), the content of the surfactant (B) is 2 parts by weight or less relative to 100 parts by weight of polyvinyl acetal (A).

[0012] According to one aspect of the present invention, a technology can be provided that can improve the odor discrimination performance in odor measurement using an odor sensor without reducing the manufacturing stability of a resin composition.

[0013] FIG. 1 is a schematic diagram showing an example of the configuration of an odor measuring device according to an embodiment of the present invention. FIG. 2 is a top view showing an example of the configuration of a sensor element. FIG. 3 is a cross-sectional view showing an example of the configuration of the sensor element shown in FIG. 2. FIG. 4 is a top view showing an example of the configuration of a sensor element. FIG. 5 is a functional block diagram showing an example of the configuration of an odor measuring device. FIG. 6 is a flowchart showing an example of the processing flow by which an estimation device generates an estimation model. FIG. 7 is a functional block diagram showing an example of the configuration of an odor measuring device. FIG. 8 is a flowchart showing an example of the processing flow by which an estimation device estimates an odor substance. FIG. 9 is a block diagram showing an example of the configuration of an odor measuring device according to another embodiment of the present invention. FIG. 10 is a schematic diagram showing an example of the configuration of an odor measuring device according to another embodiment of the present invention. FIG. 11 is a top view showing an example of the configuration of a sensor chamber. FIG. 12 is a cross-sectional view showing an example of the configuration of a sensor chamber. FIG. 13 is a top view showing an example of the configuration of a sensor element of the present invention. FIG. 14 is a flowchart showing an example of the processing flow of a method for manufacturing a sensor element. FIG. 15 is a top view showing an example of a substrate before slurry is applied.

[0014] [Embodiment 1] One embodiment of the present invention will be described below, but the present invention is not limited thereto. Furthermore, unless otherwise specified in this specification, the expression "A to B" representing a numerical range means "A or more and B or less."

[0015] In this specification, "odor substance" broadly refers to a substance that can be adsorbed onto an odor substance receiving layer. Therefore, it also includes substances that are not generally considered to be odor-causing substances. "Odor" often contains multiple odor substances that cause it, 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 an odor substance receiving layer varies depending on the type of odor substance.

[0016] In addition, even when the term "odorous substance" is simply used in this specification, it may refer to a "collection of odorous substances" that may contain multiple odorous substances, rather than an individual odorous substance.

[0017] Examples of "odor substances" include, but are not limited to, hexane, ethyl acetate, methanol, diethyl carbonate, toluene, d-limonene, bornan-2-one, cis-3-hexenol, β-phenylethyl alcohol, citral, L-carvone, γ-undecalactone, eugenol, linalyl acetate, menthol, benzaldehyde, vanillin, hexanal, ethanol, pentyl valerate, linalool, and 2-propanol.

[0018] In addition, in this specification, the term "odorant receiving layer" refers to a layer that adsorbs the odorant to be recognized. The odorant receiving layer is formed from the resin composition described above. The odorant receiving layer can be provided as part of the sensor element described below.

[0019] [1. Resin Composition] A resin composition according to one embodiment of the present invention is a resin composition for forming an odorant-receiving layer, and contains at least polyvinyl acetal (A) and a filler (C).

[0020] The resin composition contained in the conventional odorant receiving layer contains a large amount of dispersant relative to the resin used in order to sufficiently disperse the resin. However, the more dispersant, the lower the amount of resin in the resin composition, which not only reduces the sensitivity when used as an odor sensor, but also makes it difficult to demonstrate the characteristics of each type of resin. On the other hand, if the content of dispersant relative to the resin is insufficient, the filler will not be sufficiently dispersed, resulting in variations in the sensitivity of the resulting odor sensor and reduced manufacturing stability.

[0021] The present inventors discovered that by using polyvinyl acetal and a filler and setting the filler content within a specific range, production stability is not reduced even with a small amount of dispersant or no dispersant at all, leading to the invention of a resin composition and a sensor element according to one embodiment of the present invention. Furthermore, by using such a resin composition, odor discrimination performance can be improved without reducing production stability.

[0022] <Polyvinyl acetal (A)> The polyvinyl acetal (A) can be obtained by acetalization of polyvinyl alcohol with an aldehyde. Examples of the polyvinyl acetal (A) include polyvinyl butyral, polyvinyl formal, polyvinyl acetoacetal, polyvinyl alkyl acetal, polyvinyl propional, polyvinyl butyral, and polyvinyl hexylal.

[0023] Among these, polyvinyl acetal (A) is preferably polyvinyl butyral, because the sensitivity ratio of the odor sensor is improved when polyvinyl acetal (A) is polyvinyl butyral.

[0024] The polyvinyl acetal (A) more preferably has an acetalization degree of 60 to 70 mol%. In this specification, the "acetalization degree" refers to the ratio of acetalized vinyl alcohol units to all monomer units constituting the polyvinyl acetal. The acetalization degree can be calculated by "number of moles of acetal groups / (number of moles of acetal groups + number of moles of hydroxyl groups + number of moles of acetyl groups)" contained in the compound. When the acetalization degree of the polyvinyl acetal (A) is within the above-mentioned range, the odor sensor exhibits the characteristic sensitivity ratio of polyvinyl acetal.

[0025] The polyvinyl acetal (A) has a viscosity of 10.0 to 15.0 (cal / cm ３ ) １／２ (20.5 to 30.7 (J / cm ３ ) １／２ From the viewpoint of increasing the solubility of the polyvinyl acetal (A) in a process solvent (e.g., the solvent (D) described later) in the resin composition, the polyvinyl acetal (A) preferably has an SP value (solubility parameter) of 10 or more, and more preferably 11.0 (cal / cm ３ ) １／２ More preferably, it is 12.0 (cal / cm ３ ) １／２ From the viewpoint of reducing the influence of moisture in the air on the sensor element, the SP value of the polyvinyl acetal (A) is more preferably 15.0 (cal / cm ３ ) １／２ It is preferable that the value is 14.5 (cal / cm ３ ) １／２ More preferably, it is 14.0 (cal / cm ３ ) １／２ It is even more preferable that:

[0026] In the present invention, the SP value is expressed as the square root of the ratio of the cohesive energy density to the molar volume, as shown below.

[0027] SP value = (ΔE / V) 1 / 2, where ΔE is the cohesive energy density and V is the molar volume. The SP value is calculated by Robert F. Fedors et al. and is described in, for example, Polymer Engineering and Science, Vol. 14, pp. 147-154.

[0028] When the polyvinyl acetal (A) is a mixture of two or more resins, the SP value of the polyvinyl acetal (A) refers to the weight-weighted average SP value of the polyvinyl acetal (A). In other words, the polyvinyl acetal (A) may contain a polyvinyl acetal resin having an SP value outside the above range, as long as the most probable value of the SP value of the polyvinyl acetal in (A) determined by the weight average method is within the above range. When the polyvinyl acetal (A) is publicly known, the SP value of the polyvinyl acetal (A) may be a literature value or a catalog value.

[0029] <Surfactant (B)> The resin composition may contain a surfactant (B). When the resin composition contains the surfactant (B), the surfactant (B) acts as a dispersant for the polyvinyl acetal (A) and the filler (C). In addition, the surfactant (B) can improve the coatability of the resin composition when forming a sensor element by applying the resin composition. The surfactant (B) can be appropriately selected from known surfactants within a range that exhibits the above-mentioned effect.

[0030] Examples of the surfactant (B) include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants.

[0031] Examples of the anionic surfactant include alkali metal salts of carboxylic acids having 10 to 24 carbon atoms and alkali metal salts of alkylsulfonic acids having 14 to 24 carbon atoms.

[0032] Examples of cationic surfactants include halide salts of quaternary ammonium having an alkyl group having 12 to 24 carbon atoms.

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

[0034] Examples of nonionic surfactants include higher alcohol alkylene oxide adducts, alkali metal salts of carboxylic acids having 10 to 24 carbon atoms, alkali metal salts of alkylsulfonic acids having 14 to 24 carbon atoms, amine salts of polyether acid esters, and polyvinylpyrrolidone. Examples of higher alcohol alkylene oxide adducts include higher alcohol ethylene oxide adducts and higher alcohol propylene oxide adducts. These alkylene oxide adducts may have both an ethylene oxide chain and a propylene oxide chain.

[0035] The content of the surfactant (B) is 2 parts by weight or less, preferably 1.7 parts by weight or less, more preferably 1.0 part by weight or less, and even more preferably 0.5 part by weight or less, relative to 100 parts by weight of the polyvinyl acetal (A). It is particularly preferable that the resin composition is substantially free of the surfactant (B).

[0036] As used herein, "substantially free of surfactant (B)" means that the surfactant (B) may be contained in a small amount, for example, 0.1 parts by weight or less, 0.01 parts by weight or less, or 0.001 parts by weight or less per 100 parts by weight of the polyvinyl acetal (A). Most preferably, the resin composition is completely free of surfactant (B). Since the surfactant content is lower than conventional, the effect of the surfactant on the resin is reduced, and when the resin composition is used as an odor sensor, the odor discrimination performance can be improved.

[0037] <Filler (C)> In this specification, the filler (C) may be an organic filler or an inorganic filler. The filler (C) may be conductive or insulating, and can be appropriately selected depending on the type of sensor element in which the resin composition is used. Only one type of filler (C) may be used, or multiple types of fillers (C) may be mixed and used.

[0038] Examples of insulating fillers include silica powder, alumina powder, and titanium oxide powder.

[0039] A sensor element containing a resin composition according to one embodiment of the present invention is not particularly limited, and can be used, for example, as a chemiresistor. When the sensor element is used as a chemiresistor, the filler (C) contained in the resin composition is preferably a conductive filler. Examples of conductive fillers include metal-based fillers such as titanium powder and molybdenum powder; metal oxide-based fillers, carbon-based fillers, metal-coated fillers, and metal oxide-coated fillers. If the filler (C) is a conductive filler, the conductivity of the filler (C) improves the odor discrimination performance of the resulting odor sensor.

[0040] The filler (C) is preferably a carbon-based filler, and more preferably carbon black such as acetylene black or ketjen black, graphite, carbon nanotubes, graphene, etc. Among these, from the viewpoints of electrical conductivity and cost, it is more preferably one or more selected from the group consisting of carbon black, graphite, and carbon nanotubes.

[0041] Commercially available carbon black products include Ketjenblack EC (trade name of Akzo, Netherlands), Ketjenblack EC-300J (trade name of Lion Specialty Chemicals Co., Ltd.), Ketjenblack EC-600JD (trade name of Lion Specialty Chemicals Co., Ltd.), SEAST G116, 116 (trade names of Tokai Carbon Co., Ltd.), Nitelon #10 (trade name of Nippon Steel Chemical Co., Ltd.), Denka Black (trade name of Denki Kagaku Kogyo Kabushiki Kaisha), and SUPER C-65 (trade name of MTI Corporation, USA).

[0042] Commercially available carbon nanotubes include VGCF-H (product name, manufactured by Showa Denko KK).

[0043] Commercially available graphene is manufactured by Sigma-Aldrich.

[0044] The filler (C) is preferably fibrous or spherical in shape.

[0045] In the case of a fibrous form, the fiber diameter is preferably 0.1 to 10 μm, more preferably 0.1 to 5 μm, and the fiber length is preferably 0.1 to 10 μm, more preferably 1 to 10 μm.

[0046] When the particles are spherical, the primary particle size is preferably 10 nm to 200 nm, more preferably 20 nm to 150 nm, and most preferably 30 to 70 nm.

[0047] Furthermore, from the viewpoint of dispersion stability in the resin composition, the filler (C) is preferably carbon black having a particle diameter of 100 nm or less. The particle diameter of carbon black can be determined by known methods. The particle diameter of carbon black can be measured by observing with a transmission electron microscope (TEM) and analyzing the image using an image processing device (for example, a digital microscope VHX-700F manufactured by Keyence Corporation). When the carbon black is a known or commercially available product, the particle diameter, specific surface area, and pH may be literature values ​​or catalog values. Note that when literature values ​​and catalog values ​​are unknown, the specific surface area of ​​carbon black is measured according to Method A circulation method (thermal conductivity measurement method) described in JIS K6217-2:2017.

[0048] Preferably, when the filler (C) is a conductive carbon material, the specific surface area is 100 cm ２ The specific surface area of ​​the filler (C) is preferably 75 cm ２ / g or less, more preferably 50 cm ２ / g or less. The specific surface area of ​​the filler (C) is, for example, 20 cm ２ / g or more. The specific surface area of ​​the filler (C) may be 100 cm ２If the resin expansion coefficient is 0.1 / g or less, the percolation break due to the expansion of the resin is likely to occur, and the sensitivity is excellent.

[0049] In the resin composition, the content of the filler (C) is 40 to 85 wt %, relative to 100 wt % of the total of the polyvinyl acetal (A) and the filler (C). The content of the filler (C) is preferably 40 to 75 wt %, more preferably 40 to 65 wt %. When the content of the filler (C) is within the above-mentioned range, it is possible to improve the odor discrimination performance in odor measurement using an odor sensor without reducing the manufacturing stability of the resin composition. <Optional Components> The resin composition may further contain other components in addition to the polyvinyl acetal (A), surfactant (B), and filler (C) described above, as long as the effects of the present invention are obtained. Examples of other components include a solvent (D) and a plasticizer (P). The other components can be suitably used as long as both the effects of the present invention and the effects of the other components are obtained.

[0050] The solvent (D) can be blended into the resin composition from the viewpoint of improving the compatibility between the polyvinyl acetal (A) and the surfactant (B), improving the dispersibility of the filler (C) in the resin composition, or improving the coatability of the resin composition. Examples of the solvent (D) include N-methylpyrrolidone, propylene glycol monomethyl ether acetate, ethyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, toluene, and xylene.

[0051] The content of the solvent (D) in the resin composition can be appropriately determined from the above viewpoints. For example, from the viewpoint of the viscosity of the resin composition, the content of the solvent (D) in the resin composition is preferably 100 to 1000 parts by weight per 100 parts by weight of the total of the polyvinyl acetal (A), the surfactant (B), and the filler (C).

[0052] A plasticizer (P) can be blended into the resin composition to fine-tune the characteristics of the odor sensor. Examples of the plasticizer (P) include Sunflex (registered trademark) EB-300 (manufactured by Sanyo Chemical Industries, Ltd., ester of polyethylene glycol and benzoic acid, number average molecular weight 400, hydroxyl value 5.0), KF-410 (manufactured by Shin-Etsu Chemical Co., Ltd., aralkyl-modified polysiloxane compound), FL-5 (manufactured by Shin-Etsu Chemical Co., Ltd., fluorine-modified silicone), X-22-4015 (manufactured by Shin-Etsu Chemical Co., Ltd., hydroxyl group-containing silicone compound), KF-6011 (manufactured by Shin-Etsu Chemical Co., Ltd., polyether-modified polysiloxane compound), KR-5206 (manufactured by Shin-Etsu Chemical Co., Ltd., alkyd-modified polysiloxane compound), and KR-5234 (manufactured by Shin-Etsu Chemical Co., Ltd., polyester-modified polysiloxane compound).

[0053] The content of the plasticizer (P) in the resin composition is preferably 5 parts by weight or more per 100 parts by weight of the total of the polyvinyl acetal (A), surfactant (B), and filler (C) from the viewpoint of significantly adjusting the characteristics of the odor sensor, and is preferably 100 parts by weight or less from the viewpoint of film-forming properties during the production of the odor sensor.

[0054] The resin composition may contain a resin other than the polyvinyl acetal (A) as long as the effects of the present invention are not impaired. Examples of the resin other than the polyvinyl acetal (A) include an acrylic polymer, a vinyl polymer other than polyvinyl acetal, a polyurethane resin, a polyether polyol, a diene polymer, and a polyester.

[0055] <Method for Producing Resin Composition> The resin composition is obtained as a slurry by mixing polyvinyl acetal (A), surfactant (B), filler (C), and, if necessary, solvent (D), and kneading the mixture uniformly with a stirrer. When solvent (D) is added, solvent (D) is distilled off from the resin composition. Solvent (D) may be distilled off from a resin composition produced by uniform mixing, or from a coating film produced during the production of a sensor element, which will be described later.

[0056] <Major Effects> The electrical conductivity of the resin composition described above varies depending on the amount of odorant adsorbed to the resin composition. Furthermore, the process of odorant adsorption to the resin composition differs for each odorant. Therefore, by forming a detection section capable of adsorbing odorants using the resin composition, it is possible to use the resin composition in a sensor element of an odor sensor. By using the resin composition, odor discrimination performance can be improved. For example, it is possible to discriminate between real odor patterns in which multiple substances interact or real odor patterns caused by substances whose composition is unknown. Furthermore, the resin composition has excellent compositional stability and coating stability. Therefore, the stability of odor discrimination performance is improved when used in a sensor element.

[0057] The sensor described in Patent Document 1 is believed to be capable of detecting odors composed of single compounds. However, many odors are mixtures of multiple substances. The sensor described in Patent Document 1 lacks the ability to distinguish odor components in the detection section, resulting in insufficient odor discrimination performance for mixtures. Patent Document 2 demonstrates that by utilizing the differences in the chemical structure of the conductive polymers used in the detection section, the detection section can differentiate its response to various compounds via each conductive polymer, thereby enabling the recognition of odor mixtures. However, the chemical structures of conductive polymers are limited, making it difficult to sensitively separate the response of the detection section to any odor component, making it difficult to distinguish between odors composed of similar components. Patent Document 3 proposes a method in which a mixture of organic polymers, plasticizers, and conductive substances is used as the detection material in the detection section, and the penetration of odor components into the organic polymer is detected as a change in the electrical resistance of the mixture. Taking advantage of the fact that different organic polymers with different compositions allow different odor components to penetrate, multiple detection sections made of the above detection material containing organic polymers of different compositions can be arranged in parallel to form an array, enabling the recognition of odor mixtures. However, with the organic polymers and organic polymers containing plasticizers described above, even if multiple combinations of organic polymers and conductive materials are prepared, the difference in chemical properties between the organic polymers is small, so the odor discrimination performance is insufficient. These conventional technologies cannot accurately detect, for example, real odor patterns where multiple substances interact or real odor patterns caused by substances with unknown compositions.

[0058] [2. Sensor element 31] The resin composition described above exhibits different temporal changes in electrical conductivity when odorant A is adsorbed onto the resin composition than when odorant B, which is different from odorant A, is adsorbed onto the resin composition. By utilizing this property, a sensor element 31 capable of detecting and identifying odorants can be realized.

[0059] The following describes the outline and effects of a sensor element 31 to which a resin composition according to one embodiment of the present invention is applied.

[0060] The sensor element 31 includes an odorant receiving layer 315 containing the resin composition described above, a first metal wiring 313A, and a second metal wiring 313B. In the following, when there is no need to distinguish between the first metal wiring 313A and the second metal wiring 313B, they may be referred to as metal wiring 313.

[0061] In this specification, the term "odorant receiving layer" refers to a layer that adsorbs the odorant to be recognized. The odorant receiving layer is formed from the resin composition described above. The odorant receiving layer can be provided as part of a sensor element according to an embodiment of the present invention.

[0062] Here, the first metal wiring 313A and the second metal wiring 313B will be described with reference to Fig. 2 and Fig. 3. Fig. 2 is a top view showing an example of the configuration of the sensor element 31, and Fig. 3 is a cross-sectional view showing an example of the configuration of the sensor element 31 shown in Fig. 2.

[0063] 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 odorant 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 odorant 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 metal wirings that are approximately parallel to each other, as shown in FIG. 2.

[0064] As shown in FIG. 2 , metal wiring 313 including first metal wiring 313A and second metal wiring 313B may be disposed on a substrate 311. The substrate 311 may be a substrate such as glass epoxy commonly used in electronic circuits. The metal wiring 313 may be metal wiring such as copper or gold. When viewed perpendicular to the surface of the substrate, the thickness of each of the first metal wiring 313A and second metal wiring 313B is preferably 10 μm to 2 mm, more preferably 10 μm to 1 mm. When viewed parallel to the surface of the substrate, the height, i.e., thickness, of each of the first metal wiring 313A and second metal wiring 313B is preferably 1 μm to 100 μm, 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 1 mm, more preferably 1 μm to 100 μm. The length of the metal wiring 313 is preferably 10 μm to 50 mm, and more preferably 10 μm to 30 mm.

[0065] The metal wiring 313 may be disposed on a seal substrate 312. Figure 3 shows the A-A cross section of Figure 2. As shown in Figure 3, a seal substrate 312 may be disposed on a substrate 311 such as glass epoxy, and the metal wiring 313 may be disposed on the seal substrate 312. Vinyl tape 314 may be used to secure the seal substrate 312 to the substrate 311. The vinyl tape 314 may also be used to adjust the length of the exposed portion of the metal wiring 313 by masking the excess portion of the metal wiring 313. Here, the exposed portion of the metal wiring 313 is the portion where the metal wiring 313 contacts the odorant receiving layer 315. The vinyl tape 314 may also be an insulator for adjusting the length of the portion where the metal wiring 313 contacts the odorant receiving layer 315.

[0066] The odorant 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 odorant receiving layer 315 may be arranged to fill the area between the first metal wiring 313A and the second metal wiring 313B, as shown in Figures 2 and 3, for example.

[0067] If the electrical conductivity of the odorant 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 a predetermined distance (e.g., 500 μm).

[0068] The sensor element 31 is capable of detecting and distinguishing various odorous substances by applying a resin composition whose electrical conductivity changes differently over time when odorous substance A is adsorbed and when odorous substance B, which is different from odorous substance A, is adsorbed.

[0069] As shown in FIG. 4, by replacing the metal wiring 313A and 313B with piezoelectric elements 313E and 313F and electrically connecting 313E and 313F with metal wiring 313G, the sensor can be used as a membrane surface stress sensor (MSS), a different type of sensor element. Even without electrical conductivity in the odorant receiving layer, the membrane surface stress sensor can detect the generation of stress associated with odorant adsorption as a change in the electrical conductivity of the piezoelectric element over time, thereby detecting and identifying various odorants. When a resin composition is used in a membrane surface stress sensor, the filler in the resin composition is used to increase the Young's modulus of the odorant receiving layer and improve sensitivity. Therefore, electrical conductivity is not essential for the filler, and insulating fillers can be used.

[0070] <Method for manufacturing sensor element> The sensor element 31 can be manufactured by producing an odorant receiving layer 315 using the resin composition according to the embodiment of the present invention described above. The odorant receiving layer 315 can be produced by applying the resin composition as a coating liquid and solidifying or curing the formed coating. The resin composition can be applied using known coating techniques.

[0071] In addition, if the polymerization reaction of resin (A) can be carried out in a coating film, the odorant receiving layer 315 may be produced by applying a composition containing a monomer of resin (A) to the seal substrate 312 instead of the resin composition, and polymerizing the monomer in the resulting coating film. Examples of such monomers include radically polymerizable monomers, and examples of resin (A) synthesized by such monomers include acrylic polymers. The composition containing the monomer may further contain additives used in the polymerization of the monomer to the extent that the effects of the present invention can be achieved. Examples of such polymerization additives include polymerization initiators for radical polymerization.

[0072] 3. Odor Sensor 30 The following describes the overview and effects of an odor sensor 30 employing a sensor element 31, with reference to Fig. 1. Fig. 1 is a schematic diagram showing an example of the configuration of an odor measurement device 100 equipped with an odor sensor 30 employing a sensor element 31. Note that in the sensor element 31 shown in Fig. 1, the vinyl tape 314 is omitted for simplicity.

[0073] The odor sensor 30 includes a sensor element 31 that detects odor substances, a constant current source 32 (power supply), and a voltmeter 33 (measuring device).

[0074] The first metal wiring 313A and the second metal wiring 313B of the sensor element 31 are connected by a lead wire W. Fig. 1 shows an example in which a constant current source 32 and a voltmeter 33 are connected to the lead wire W.

[0075] The constant current source 32 is a power source for supplying power to the sensor element 31. The constant current source 32 supplies a constant current (for example, a direct current of 1 mA) to the sensor element 31 via lead wires.

[0076] The voltmeter 33 measures the potential difference that occurs between the first metal wiring 313A and the second metal wiring 313B when a constant current supplied from the constant current source 32 is supplied to the odorant receiving layer 315.

[0077] Although not a required component, the odor sensor 30 may further include a housing 34. The housing 34 is a container capable of containing air containing an odor substance. When the housing 34 is included, the sensor element 31 is installed within the housing 34.

[0078] The housing 34 has an inlet 341 for introducing an odorant and an outlet 342 for discharging air containing the odorant. The odorant may be introduced by inserting filter paper P or the like soaked in the odorant into the housing 34 through the inlet 341, or by introducing air containing the odorant into the housing 34 through the inlet 341. The housing 34 is a container for containing air containing the odorant at a predetermined concentration (e.g., 200 ppm) or more.

[0079] Although not essential, 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 generate an airflow inside the housing 34 and to exhaust gas inside the housing 34 from the exhaust port 342 to the outside of the housing 34.

[0080] The odor sensor 30 may include a constant voltage source (power supply) (not shown) instead of the constant current source 32, and an ammeter (measuring device) (not shown) instead of the voltmeter 33. In this case, the constant voltage source functions as a power source for supplying power to the sensor element 31, and applies a constant voltage to the sensor element 31 via lead wires. Meanwhile, the ammeter measures the value of the current flowing between the first metal wiring 313A and the second metal wiring 313B when a constant voltage is applied to the odorant receiving layer 315.

[0081] The odor sensor 30 outputs a measurement value that indicates the change over time in the electrical conductivity of the sensor element 31 before and after an odor substance is adsorbed to the sensor element 31. This makes it possible to detect and distinguish various odor substances.

[0082] [4. Odor Measuring Device 100] When various odor substances are adsorbed onto the sensor element 31, 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. 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 the results of such comparison, it is possible to realize an odor measuring device 100 that can estimate the odor substance adsorbed onto the sensor element 31.

[0083] Furthermore, the odor measuring device 100 can estimate odor substances with high accuracy 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 ​​measured when each of a plurality of odor substances is adsorbed onto at least one sensor element 31 and identification information unique to the odor substance that provided the measurement value.

[0084] The following describes the outline and effects of an odor measurement device 100 that uses the odor sensor 30. The odor measurement device 100 is a device that estimates odor substances adsorbed to a sensor element 31 based on changes in electrical conductivity that occur in the sensor element 31 to which the above-described resin composition is applied.

[0085] First, the configuration of an odor measurement device 100 according to one embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a block diagram showing an example of the configuration of the odor measurement device 100.

[0086] As shown in FIG. 1 , the odor measurement device 100 includes an estimation device 10 and an odor sensor 30 .

[0087] <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 includes a CPU and memory (not shown). The estimation device 10 is communicatively connected to the odor sensor 30. Specifically, the estimation device 10 performs estimation of odor substances by analyzing measurement values ​​acquired from the odor sensor 30. The configuration of the estimation device 10 will be described later.

[0088] (Generation of Estimation Model 22) Next, the configuration of the odor measurement device 100 that performs processing to generate the estimation model 22 used to estimate odor substances, and the processing to generate the estimation model 22 will be described with reference to Figures 5 and 6.

[0089] The estimation model 22 is generated by machine learning using training data that includes a combination of measurement 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 specific to the odor substance that provided the measurement value. Here, the identification information specific to the odor substance may be, for example, the name, CAS number, or chemical formula of the odor substance.

[0090] The process of generating the estimation model 22 may include data preprocessing and feature extraction. Furthermore, the machine learning for generating the estimation model 22 may use a machine learning algorithm.

[0091] (Feature Extraction) The learning data for generating the estimation model 22 by machine learning may be the measurement values ​​themselves or may be feature values ​​extracted from the measurement values. The feature values ​​may be, for example, statistics, differential and integral values, peak detection values, or autocorrelation values. Examples of statistical quantities include the mean value, variance, maximum value, minimum value, the difference between the maximum and minimum values, and standard deviation. Examples of differential and integral values ​​include the differential value (the slope of a graph showing the change in measurement values ​​over time) and the integral value (the area of ​​a region defined by a curve showing the change in measurement values ​​and the horizontal axis (e.g., time axis) in a graph showing the change in measurement values ​​over time). Examples of peak detection values ​​include the number and height of peaks in the change in measurement values ​​(e.g., change over time). Examples of autocorrelation values ​​include the difference in the change in measurement values ​​(e.g., change over time). These feature values ​​can be extracted from the measurement values ​​based on known methods.

[0092] (Preprocessing Method) The learning data for generating the estimation model 22 by machine learning may be used for machine learning without preprocessing, or may be used after performing predetermined preprocessing as necessary. Furthermore, when preprocessing is performed, it may be performed before the feature extraction, after the feature extraction, or both before and after the feature extraction. Preprocessing may be performed by a known method. Known methods include correction, noise removal, standardization, data transformation, smoothing, and data expansion. Examples of correction include integration, addition, subtraction, and division using output ratios, independent component analysis (ICA), or statistics based on the measurement results of a standard gas using multiple sensor elements or commercially available sensors (e.g., temperature sensors or humidity sensors). Examples of noise removal include removal of outliers, white noise, and other noise. Examples of standardization include normalization and regularization of features. Examples of data transformation include removal of data trends, frequency transformation, and logarithmic transformation. Examples of smoothing include obtaining a moving average and difference of data. Examples of data expansion include adding the same sample data (for example, adding data assuming a normal distribution), adding new sample data (for example, adding data related to the mixture ratio of vectors), and the like.

[0093] (Machine Learning Algorithm) Machine learning algorithms applicable to the estimation model generation unit 14 include regression analysis, classification, tree, time series analysis, neural network, and clustering. Examples of regression analysis include logistic regression, Lasso regression, elastic net regression, support vector regression (SVR), linear regression, ridge regression, and ensemble regression. Examples of classification include k-nearest neighbor method, support vector classification (SVC), Naive Bayes classifier, stochastic gradient descent (SGD), and kernel approximation. Examples of trees include decision trees, regression trees, random forests, boosting (lightGBM, XGboost), and stacking. Examples of time series include AR, MA, ARIMA, and state space. Examples of neural networks include multi-layer perceptrons (MLPs), convolutional neural networks (CNNs), recurrent neural networks (RNNs), residual neural networks (ResNets), transformers, and graph neural networks (GNNs). Examples of clustering include Gaussian mixture models (GMMs), k-means, mini k-means, variational Gaussian mixture models (VBGMMs), and kernel approximation.

[0094] (Configuration of Estimation Device 10 (Generation of Estimation Model 22)) Fig. 5 is a functional block diagram showing an example of the configuration of the odor measurement device 100. For ease of explanation, components having the same functions as those described in Fig. 1 are denoted by the same reference numerals, and their description will not be repeated.

[0095] As shown in FIG. 5, the estimation device 10 includes an input unit 15, a control unit 1, and a storage unit 2.

[0096] The input unit 15 is for accepting various input operations from the user, and may be, for example, a keyboard, a mouse, a touch panel, or the like.

[0097] The control unit 1 includes 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.

[0098] The measurement value acquiring unit 11 acquires a measurement value from the voltmeter 33. Furthermore, the measurement value acquiring unit 11 uses the acquired measurement value to calculate a value indicating the electrical conductivity of the sensor element 31 (e.g., resistance value, impedance, etc.). The measurement value acquiring unit 11 may acquire the measurement value from the voltmeter 33 at predetermined time intervals (e.g., 0.1 second intervals).

[0099] The change pattern analysis unit 12 analyzes the change over time in the electrical conductivity of at least one sensor element 31. Using the resistance value calculated by the measurement value acquisition unit 11, the change pattern analysis unit 12 calculates a value indicating the amount of change in the electrical conductivity of the sensor element 31 due to the adsorption of an odorant. The change pattern analysis unit 12 generates data indicating a change pattern that indicates the time change in the calculated amount of change in electrical conductivity. If the generated change pattern is for a known odorant, the change pattern analysis unit 12 may associate the generated change pattern with identification information unique to the known odorant and store it in the change pattern database 21 (learning data).

[0100] The learning control unit 13 reads the change pattern database 21 from the storage unit 2 and controls the generation of the estimation model 22 by machine learning. Here, the change pattern database 21 is a database containing combinations of measurement values ​​measured when multiple odor substances are adsorbed onto the sensor element 31 and identification information unique to the known odor substances that provided the measurement values. The learning control unit 13 inputs the change patterns read from the change pattern database 21 to the estimation model generation unit 14. In addition, the learning control unit 13 compares the identification information of the odor substances corresponding to the change pattern input to the estimation model generation unit 14 with the estimation results output from the estimation model generation unit 14, and outputs correction instructions to the estimation model generation unit 14 according to the comparison results.

[0101] The estimation model generation unit 14 generates the estimation model 22 by a machine learning algorithm using the change patterns stored in the change pattern database 21. The estimation model generation unit 14 may be configured to generate the estimation model 22 by using a known supervised machine learning algorithm. Examples of machine learning algorithms that can be applied to the estimation model generation unit 14 include the k-nearest neighbor method, logistic regression, support vector machines, random forests, and neural networks.

[0102] (Process for Generating Estimation Model 22) Specific processes performed by each unit of the control unit 1 will be described below with reference to Fig. 6. Fig. 6 is a flowchart showing an example of the flow of processes performed by the estimation device 10 to generate the estimation model 22.

[0103] First, the measurement value acquisition unit 11 acquires the voltage value V0 measured by the odor sensor 30 before the filter paper P soaked in the odor substance is inserted into the housing 34, and calculates the resistance value R0 (step S11). The resistance value R0 is preferably 200 to 1000 Ω, more preferably 250 to 900 Ω, and most preferably 300 to 800 Ω.

[0104] Meanwhile, the input unit 15 receives input such as the name of a known odor substance that has been soaked in the filter paper P inserted into the housing 34 (step S12). The processing of step S12 may be performed before step S11.

[0105] Next, the measurement value acquisition unit 11 acquires the voltage value V measured by the odor sensor 30 immediately after the filter paper P soaked in the known odor substance is inserted into the housing 34, and calculates the resistance value R.

[0106] (Step S13) Next, the change pattern analysis unit 12 calculates R / R0 using the resistance values ​​R0 and R (Step S14). R / R0 is a value indicating the amount of change in the electrical conductivity of the sensor element 31 due to the adsorption of a known odorant. Note that the change pattern analysis unit 12 may calculate R-R0 instead of R / R0. The change pattern analysis unit 12 stores the change pattern of R / R0 over time in the change pattern database 21 in association with the name of the input known odorant (Step S15).

[0107] If no change pattern is stored for a predetermined type of existing odor substance (NO in step S16), that is, if there is still insufficient data to use for machine learning, return to step S11.

[0108] If a change pattern is stored for a predetermined type of existing odor substance (YES in step S16), the learning control unit 13 reads out the change pattern for the known odor substance stored in the change pattern database 21 and inputs it to the estimation model generation unit 14. The estimation model generation unit 14 generates an estimation model 22 by a machine learning algorithm using the change pattern stored in the change pattern database 21 (step S17).

[0109] The estimation model generation unit 14 stores the estimation model 22 generated by predetermined machine learning in the storage unit 2 (step S18).

[0110] 5 and 6 , the estimation device 10 generates the estimation model 22, but this is not limiting. For example, the estimation device 10 may provide the same data as the change pattern database 21 to an external computer different from the estimation device 10 that has the same functions as the learning control unit 13 and the estimation model generation unit 14, and have the computer generate the estimation model 22.

[0111] (Odor Substance Estimation) Next, the configuration of the odor measurement device 100a that estimates odor substances using the estimation model 22 and the estimation process will be described with reference to FIGS. 7 and 8. FIG.

[0112] (Configuration of Estimation Device 10a (Execution of Estimation Process)) Fig. 7 is a functional block diagram showing an example of the configuration of odor measurement device 100a. For ease of explanation, components having the same functions as those described in Figs. 1 and 5 are denoted by the same reference numerals, and their description will not be repeated.

[0113] As shown in Fig. 7, the estimation device 10a includes a control unit 1a, a storage unit 2a, and an output unit 18. Fig. 7 shows a configuration example in which the estimation device 10 shown in Fig. 5 is used for odor substance estimation processing. That is, the estimation device 10 shown in Fig. 5 and the estimation device 10a shown in Fig. 7 may be computers with the same hardware configuration.

[0114] The output unit 18 is for presenting the estimation result to the user, and may be, for example, a display, a speaker, a lamp, or the like.

[0115] The control unit 1 a 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 .

[0116] The estimation unit 16 uses the estimation model 22 to estimate the odor substance from the analysis results obtained by analyzing the measurement values ​​obtained from the odor sensor 30.

[0117] The output control unit 17 controls the output unit 18 to output the estimation result.

[0118] (Estimation Process) The specific processes performed by each unit of the control unit 1a will be described below with reference to Fig. 8. Fig. 8 is a flowchart showing an example of the process flow for the estimation device 10a to estimate an odor substance.

[0119] First, the measurement value acquisition unit 11 acquires the voltage value V0 measured by the odor sensor 30 before the filter paper P soaked in the odorous substance is inserted into the housing 34, and calculates the resistance value R0 (step S1).

[0120] Next, the measurement value acquisition unit 11 acquires the voltage value V measured by the odor sensor 30 immediately after inserting the filter paper P soaked in the unknown (i.e., the odor substance to be estimated) into the housing 34, and calculates the resistance value R (step S2).

[0121] Next, the change pattern analysis unit 12 calculates R / R0 using the resistance value R0 and the resistance value R (step S3).

[0122] Next, the estimation unit 16 estimates the unknown odor substance from the pattern of change in R / R0 over time based on the estimation model 22 (step S4).

[0123] The output control unit 17 controls the output unit to output the estimation result (step S5).

[0124] [Embodiment 2] In the above embodiment, the odor sensor 30 has been described as having one sensor element 31, but the odor sensor 30 may also have two or more sensor elements 31. For example, the odor sensor 30b may have sensor elements 31, 31b in which the resin compositions used in the odorant receiving layer 315 are different from each other. This will be explained using FIG. 9. FIG. 9 is a block diagram showing an example of the configuration of an odor measuring device 100b according to another embodiment of the present invention. For ease of explanation, components having the same functions as those described in FIG. 1 are denoted by the same reference numerals, and their explanations will not be repeated.

[0125] 9 includes odor sensors 30 and 30b and an estimation device 10b. The odor sensor 30b includes a sensor element 31 and a sensor element 31b, and the resin composition used in the odorant receiving layer 315 of the sensor element 31 and the odorant receiving layer 315b of the sensor element 31b may be different.

[0126] The estimation device 10b may be a computer having the same configuration as the estimation devices 10 and 10a. The estimation device 10b acquires and analyzes a first measurement value measured by a voltmeter 33 when a constant current is supplied from a constant current source 32 to the sensor element 31, and a second measurement value measured by a voltmeter 33b when a constant current is supplied from a constant current source 32b to the sensor element 31b.

[0127] By providing multiple sensor elements each having an odorant receiving layer made of a resin composition with different odorant adsorption properties, the odor measuring device 100b can simultaneously estimate multiple odorants. In addition to the sensor element according to one embodiment of the present invention, a sensor element that does not contain surfactant (B) in the odorant receiving layer may also be used.

[0128] Furthermore, by using the odor measurement device 100b, it is possible to obtain, for each known odor substance, a first change pattern indicating a change in the electrical conductivity of the sensor element 31 and a second change pattern indicating a change in the 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. The odor measurement device 100b estimates odor substances using the estimation model 22 generated in this way, and therefore is able to more precisely identify each odor substance.

[0129] [Embodiment 3] Hereinafter, one embodiment of the present invention will be described in detail.

[0130] The odor measurement device 100b of the second embodiment is configured such that a filter paper P soaked in an odorant is introduced into a housing 34 containing two sensor elements (i.e., sensor elements 31 and 31b). With this configuration, it is not possible to control the timing at which the odorant reaches the sensor elements 31 and 31b, or to adjust the concentration of the odorant. Therefore, the odor measurement device 100c of the second embodiment is separately equipped with a sensor chamber 60 containing multiple sensor elements (hereinafter, sensor element group 31A), and a target sample receiving section 50 into which a target sample containing an odorant is introduced and into which gas containing the odorant generated from the target sample is enclosed. In this embodiment, each sensor element included in the sensor element group 31A will be referred to simply as a "sensor element."

[0131] The odor measurement device 100c of this embodiment employs a configuration in which the gas containing the odor substance inside the target sample receiving section 50 is pushed toward 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. Meanwhile, the carrier gas used to push the first gas toward the sensor chamber 60 is referred to as the second gas.

[0132] Fig. 10 is a schematic diagram of an odor measurement device 100c. As shown in Fig. 10, the odor measurement device 100c includes a target sample receiving unit 50, a sensor chamber 60, a gas supply unit 80, and an estimation device 10b. The odor measurement device 100c may further include a regulator 51.

[0133] 10 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 each connected by a tube.

[0134] The target sample receiving section 50 is capable of receiving a target sample containing an odorant therein and retaining a first gas. The target sample receiving section 50 has a first port 501 through which a second gas entering the inside passes, and a second port 502 through which the first gas and the second gas exiting the inside can pass. The target sample receiving section 50 may also have a sample inlet 503, which will be described later.

[0135] 10 shows an embodiment in which the first port 501 is located at the top of the target sample receiving section 50 and the second port 502 is located at the bottom of the target sample receiving section 50, but this is not limiting. For example, the positions of the first port 501 and the second port 502 can be set appropriately 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 of the odor components contained in the first gas (i.e., specific gravity) is heavier or lighter than that of the second gas. Furthermore, the target sample receiving section 50 may be internally provided with an airflow generating fan 35, as in FIG. 9 .

[0136] The target sample receiving unit 50 includes a sample inlet 503 for receiving a liquid or solid target sample. Similar to FIG. 9 , FIG. 10 shows a filter paper P soaked in an odorant being introduced as the target sample. The target sample receiving unit 50 may also include a mounting unit (not shown) for mounting the target sample. If the target sample is a liquid, the mounting unit may be a cup for holding the liquid. If the target sample is a solid, the mounting unit may be a Petri dish on which the solid is placed. The target sample may be introduced into the target sample receiving unit 50 in a gaseous state as a first gas through the sample inlet 503. In this way, the target sample receiving unit 50 can receive a liquid or solid target sample, making it possible to adjust the concentration of the odorant in the first gas. For example, even if the same odorant is used, it is easy to adjust the concentration of the odorant in the first gas.

[0137] A material inactive to odorants may be arranged on the inner surface of the target sample receiving portion 50. A material inactive to odorants is a material that does not significantly change the concentration of each odorant contained in the gas sent to the sensor chamber 60. For example, a material inactive to odorants is a material that odorants are unlikely to adsorb or dissolve into. Examples of materials inactive to odorants include glass, metal, and resin. When metal is used, stainless steel (SUS) is preferred, and when resin is used, fluorine-based resin, polypropylene (PP), polyethylene (PE), ABS resin, and polyethylene terephthalate (PET) are preferred.

[0138] If the inner surface of the target sample receiving portion 50 is made of a material that adsorbs the odorous substances contained in the first gas, the odorous substances may be adsorbed to various parts, which may affect subsequent measurements.

[0139] Since the inner surface of the target sample receiving portion 50 is made of a material that is inactive to odorants, the risk of the material of the inner surface reacting with the odorants contained in the first gas, or the odorants being adsorbed onto the inner surface, is reduced. Therefore, the risk of the odorants contained in the first gas supplied to the sensor chamber 60 changing while contained in the target sample receiving portion 50, or the concentration of the odorants being diluted, is reduced.

[0140] Whether the target sample is a liquid or a solid, the odor measurement device 100c is provided with a target sample receiving section 50, thereby making the concentration of the first gas uniform within the target sample receiving section 50 before sending the first gas into the sensor chamber 60. Furthermore, by providing the target sample receiving section 50, the odor measurement device 100c can push the first gas into the sensor chamber 60 at a constant flow rate. This allows the odor measurement device 100c to send the first gas to the sensor chamber 60 under the same conditions each time, even when measurements are repeated, thereby enabling repeated, stable measurements.

[0141] The volume of the target sample receiving section 50 is preferably between 1 and 100 times the volume of the sensor chamber 60. In particular, the volume of the target sample receiving section 50 is preferably larger than the volume of the sensor chamber 60. The volume of the target sample receiving section 50 is more preferably between 2 and 80 times the volume of the sensor chamber 60, and even more preferably between 4 and 60 times the volume of the sensor chamber 60. By making the volume of the target sample receiving section 50 at least 1 time larger than the volume of the sensor chamber 60, the concentration of odor substances in the sensor chamber 60 is appropriately adjusted, and measurement results by the sensor provided in the sensor chamber 60 are stably output. Furthermore, by making the volume of the target sample receiving section 50 less than 100 times the volume of the sensor chamber 60, measurement results by the sensor are stably output, and the odor measurement device 100c can be compactly configured.

[0142] If the volume of the target sample receiving section 50 is less than one time the volume of the sensor chamber 60, the odor substances generated in the target sample receiving section 50 may be diluted in the sensor chamber 60, which may reduce the measurement sensitivity of the sensor. Also, if the volume of the target sample receiving section 50 is more than 100 times the volume of the sensor chamber 60, the volume of the target sample receiving section 50 may be too large, which may increase the overall size of the odor measuring device 100c.

[0143] FIG. 10 shows an example in which the volume of the target sample receiving portion 50 is eight times the volume of the sensor chamber 60 .

[0144] For example, if the inner surface of the tube 93 is made of a material that adsorbs odorous substances contained in the first gas, the odorous substances may be adsorbed to 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 inactive to odorous substances, similar to the inner surface of the target sample receiving section 50. Examples of materials that are inactive to the first gas include glass, metal, and resin. When metal is used, stainless steel (SUS) is preferred, and when resin is used, fluorine-based resin, polypropylene (PP), polyethylene (PE), ABS resin, and polyethylene terephthalate (PET) are preferred.

[0145] The target sample receiving section 50 may be configured to be detachable from the tubes 92 and 93. In this way, since the target sample receiving section 50 is 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 target sample receiving section 50. This allows the odor measurement device 100c to perform multiple measurements in a short period of time.

[0146] Furthermore, because the target sample receiving unit 50 is detachable, the target sample receiving unit 50 into which the target sample has been introduced can be maintained at a desired temperature using a temperature-retaining chamber separate from the odor measurement device 100c. This allows the odor measurement device 100c to adjust the temperature of the target sample receiving unit 50, even if, for example, the odor measurement device 100c cannot be provided with the adjustment unit 51 described below.

[0147] The adjustment unit 51 adjusts at least one of the temperature and humidity of the first gas contained in the target sample receiving unit 50. When the adjustment unit 51 adjusts the temperature, the adjustment unit 51 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, the adjustment unit 51 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 may change at least one of the temperature and humidity at predetermined time intervals during measurement of the same first gas.

[0148] The adjustment unit 51 adjusts at least one of the temperature and humidity of the first gas in the target sample receiving unit 50, so that the odor measuring device 100c can send the first gas to the sensor chamber 60 using conditions according to, for example, the type of the first gas (such as the weight or volatility of the gas). This also allows the odor measuring device 100c to send the first gas at a stable concentration to the sensor chamber 60, improving measurement accuracy.

[0149] The gas supply unit 80 is connected to the first port 501 of the target sample receiving unit 50, and by sending a second gas into the inside of the target sample receiving unit 50, the first gas is sent from inside the target sample receiving unit 50 toward the sensor chamber 60.

[0150] A valve 81 may be provided between the gas supply unit 80 and the target sample receiving unit 50. By opening and closing the valve 81, start and stop of gas supply from the gas supply unit 80 may be adjusted.

[0151] In this way, the gas supply unit 80 pushes the gas from the first port 501 side of the target sample receiving unit 50 to send the first gas into the sensor chamber 60, so the pressure inside the sensor chamber 60 is positive. This allows the odor measurement device 100c to obtain stable measurement results. Furthermore, because the second gas can be sent by opening and closing the valve 81, the odor measurement device 100c can send the first gas from the target sample receiving unit 50 toward the sensor chamber 60 at any timing. This allows the odor measurement device 100c to improve the reproducibility of the waveform shape output by each sensor element when repeatedly measuring odor substances contained in the first gas using the sensor element group 31A.

[0152] The second gas may be an inert gas or air. Examples of the inert gas include argon and nitrogen. When the second gas is an inert gas, the gas supply unit 80 may be a gas cylinder.

[0153] Furthermore, when the second gas is air, the gas supply unit 80 may be a pump. In this case, the odor measuring device 100c may be provided with, for example, an activated carbon filter on the first port 501 side of the target sample receiving unit 50 in order to remove components that react with the first gas contained in the target sample receiving unit 50.

[0154] The odor measurement device 100c may further include a mass flow controller on the side of the first port 501 of the target sample receiving unit 50, more specifically, between the valve 81 and the gas supply unit 80. The odor measurement device 100c employing this configuration can send the first gas from the target sample receiving unit 50 to the sensor chamber 60 at a constant flow rate, allowing the sensor elements of the sensor element group 31A to produce stable outputs.

[0155] The estimation device 10b has the same functions as the estimation device 10b of embodiment 2. If the sensor chamber 60 further includes a sensor element 31c whose substance receiving layer 315 uses a resin composition different from that of the sensor element 31 and the sensor element 31b, the estimation device 10b may further acquire and analyze measurements taken by a voltmeter by supplying a constant current to the sensor element 31c. The estimation device 10b may also display the measurement values ​​themselves, waveforms plotting the measurement values, and estimation results for unknown odor substances based on an estimation model. The estimation device 10b may also display numerical values ​​and graphs showing changes in the abundance ratio of each odor substance in a gas containing multiple odor substances.

[0156] The sensor chamber 60 is a space that houses the sensor element group 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 includes a gas supply port 601 and a gas exhaust port 602, and the second port 502 of the target sample receiving section 50 is connected to the gas supply port 601.

[0157] The sensor chamber 60 has multiple passages in which multiple sensor elements are arranged, each capable of outputting a measurement result according to the odorant contained in the gas. This reduces the time required from when gas begins to be sent into the sensor chamber until all of the multiple sensor elements stably output a measurement result. Furthermore, by finely dividing the multiple sensor elements by multiple passages, the variation in airflow turbulence between measurements is reduced, improving measurement accuracy.

[0158] Fig. 11 is a top view showing an example of the configuration of sensor chamber 60. Fig. 11 shows sensor chamber 60 having four passages (i.e., passage 61, passage 62, passage 63, and passage 64). The first gas can be supplied from target sample receiving portion 50 to each of passages 61 to 64.

[0159] Each of the multiple passages (passages 61-64) may be provided with multiple sensor elements that output different measurement results for each odorant. The multiple sensor elements that output different measurement results for each odorant may each have a different resin composition as a substance-receiving layer. That is, the multiple sensor elements arranged in one passage may have different sensitivities and detection specificities for each odorant. The sensor chamber 60 in FIG. 11 includes, as an example, the sensor element 31 and the sensor element 31b described in embodiment 2 (FIG. 9) in the passage 61, but is not limited thereto. For example, the sensor element 31 and the sensor element 31b may be capable of outputting measurement results corresponding to the same odorant contained in the first gas, but the measurement results output by each sensor element may be different. Furthermore, the sensor element 31 and the sensor element 31b may be capable of outputting measurement results corresponding to different odorants. The measurement results corresponding to an odorant may be, for example, measurement results corresponding to the concentration of the odorant. By arranging multiple sensor elements in each of the multiple passages, each of which outputs a different measurement result for each odor substance, the odor measurement device 100c can detect odor substances passing through a single passage using sensor elements with different sensitivities and detection specificities. This allows the odor measurement device 100c to comprehensively detect odor substances from multiple different measurement results.

[0160] 11 , similar to passage 61, passage 62 is provided with a plurality of sensor elements (such as sensor elements 31c and 31d) capable of outputting measurement results corresponding to the odorous substances contained in the first gas. Passage 63 is provided with a plurality of sensor elements (such as sensor elements 31e and 31f) capable of outputting measurement results corresponding to the odorous substances contained in the first gas. Passage 64 is provided with a plurality of sensor elements (such as sensor elements 31g and 31h) capable of outputting measurement results corresponding to the odorous substances contained in the first gas. These sensor elements may have different resin compositions used in the substance receiving layer 315.

[0161] Note that some of the sensor elements 31 to 31h may have the same detection specificity for odor components. That is, for example, if the sensor element group 31A arranged in the sensor chamber 60 includes n sensor elements, m types of sensor elements (m<n) may be arranged. Also, some of the multiple sensor elements arranged in the same passage may have the same detection specificity for odor components.

[0162] Furthermore, the sensor chamber 60 has passages 61 to 64, and a plurality of sensor elements may be arranged in each of the passages 61 to 64. In this case, the plurality of sensor elements arranged in each of the passages 61 to 64 constitutes the sensor element group 31A. For example, four sensor elements may be arranged in the passage 61, and ten sensor elements may be arranged in the passage 62.

[0163] When different numbers of sensor elements are arranged in each of passages 61 to 64, it is preferable that the difference in the number of sensor elements arranged in each of passages 61 to 64 be 10 or less. By having the difference in the number of sensor elements arranged in each of passages be 10 or less, it is possible to reduce the variation in the timing at which odor substances are detected by the sensor elements, which may occur depending on the passage. Furthermore, by having the difference in the number of sensor elements arranged in each of passages 61 to 64 be 10 or less, the odor measuring device 100c can perform odor measurement in a short time.

[0164] Each of the passages is connected to a pipe 93 for supplying the first gas into the interior space of the sensor chamber 60. As shown in Figure 11, passages 61, 62, 63, and 64 are all connected to one pipe 93.

[0165] 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 rate than when passing through the pipe 93. This minimizes the time lag in measurement between the sensor element located closer to the gas supply port 601 and the sensor element located closer to the gas discharge port 602, allowing the odor measuring device 100c to perform highly accurate measurements.

[0166] Furthermore, it is preferable that the gas in each internal space of the passage be replaced within one second after the supply of the first gas begins. The supply of the first gas begins when the first gas is supplied to the gas supply port 601. Furthermore, replacement of the gas in the internal space indicates that the first gas supplied from the gas supply port 601 has reached the gas exhaust port 602. In this way, by replacing the gas in each internal space of the passage within one second after the supply of the first gas and the second gas begins, the difference in timing at which the first gas comes into contact with each sensor element is reduced, allowing the odor measurement device 100c to perform stable measurements. Furthermore, by replacing the gas in each internal space of the passage within one second after the supply of the first gas and the second gas begins, the odor measurement device 100c can perform odor measurements in a short time.

[0167] The flow rate of the first gas passing through each internal space of the passage is preferably 0.1 cm / sec or more and 100 cm / sec or less. Furthermore, the flow rate of the first gas passing through each internal space of the passage is more preferably 1 cm / sec or more and 50 cm / sec or less. The flow rate 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 a mass flow controller (described later).

[0168] If the flow rate of the first gas passing through each internal space of the passage is slow, there will be a large difference in the timing at which the first gas comes into contact with all of the sensor elements of the sensor element group 31A. On the other hand, if the flow rate of the first gas passing through each internal space of the passage is too fast, the sensor elements of the sensor element group 31A will vibrate due to the influence of the airflow, and the odor measurement device 100c will not be able to perform stable odor measurement. Furthermore, if the flow rate 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 to the sensor elements of the sensor element group 31A will be hindered, and the odor measurement device 100c will not be able to perform accurate odor measurement. Furthermore, if the flow rate 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 portion 50 will be consumed before the odor measurement device 100c can perform stable measurement.

[0169] In this way, since the flow velocity of the first gas passing through the internal space of each passage is not less than 0.1 cm / sec and not more than 100 cm / sec, the odor measuring device 100c can stably measure odors.

[0170] The passages may be arranged in parallel. In Fig. 11, passages 61 to 64 are arranged in parallel with one another. By arranging the passages in parallel in this way, the odor measuring device 100c can secure space for arranging the passages, and the size of the entire device can be made compact.

[0171] Fig. 12 is a cross-sectional view schematically showing a cross section taken along line BB in Fig. 11. The passage 61 in Fig. 12 is composed of a side wall 610, a side wall 611 opposite to the side wall 610, a ceiling 621, and a substrate 630 which is the bottom surface.

[0172] 12 shows sensor chamber 60 in which passage 61 has a rectangular cross section, but there are no particular limitations on the cross section of passage 61. For example, passage 61 may have a circular arc or a triangular cross section.

[0173] The passage 61 and the passage 62 are completely separated by a side wall 611 and a side wall 612 , and a configuration may be adopted in which gas cannot pass between the passage 61 and the passage 62 .

[0174] 12 shows an example in which two side walls (side wall 611 and side wall 612) are provided between the passage 61 and the passage 62, but the present invention is not limited to this. For example, the passage 61 and the passage 62 may be separated by a single side wall.

[0175] 12 is formed as a single unit, the present invention is not limited to this configuration. The entire sensor chamber 60 may be formed as a single unit, or each of the multiple passages may be formed as a separate body.

[0176] 12 includes the sensor element 31 on the substrate 630, which is the bottom surface of the passage 61, but the placement of the sensor element 31 is not limited to this. The sensor element 31 may be placed, for example, taking into consideration the type of target odorant that the sensor element 31 can specifically detect. For example, the sensor element 31 may be placed on any of the sidewall 610, the sidewall 611, and the ceiling 621. Specifically, if the odorant is lighter than air, the sensor element 31 may be placed on the ceiling 621. In this way, by placing the sensor element 31 in a location appropriate for the type of odorant, the odor measuring device 100c can perform highly accurate measurements.

[0177] In FIG. 12, the sensor chamber 60 includes each sensor element on a substrate 630, but may further include a connector between the substrate 630 and each sensor element to connect the substrate 630 and the sensor element.

[0178] Each sensor element may be independently connected to the substrate 630. For example, one embodiment is where each sensor element is connected to the substrate 630 via a connector (e.g., an IC pin). In this way, even if a malfunction occurs in only one sensor element included in the sensor chamber 60, the user can replace only the malfunctioning sensor element.

[0179] Furthermore, when detecting odor substances using multiple types of sensor elements, the optimal combination and placement of the sensor elements to be used will vary depending on the type of odor substance. Because each sensor element is independently connected to the substrate 630 and is detachable, the odor measurement device 100c can easily change the optimal combination and placement of sensor elements depending on the odor substance.

[0180] The sensor elements may be disposed in two or more locations, such as the substrate 630, the sidewall 610, the sidewall 611, and the ceiling 621. This allows the length of the passage 61 to be shorter than when sensor elements are provided on only one surface, thereby making the odor measuring device 100c more compact. Furthermore, because multiple sensor elements can be provided near the gas supply port 601, the odor measuring device 100c can perform odor measurement in a shorter time than when the sensor elements are arranged in a row facing the gas discharge port 602.

[0181] The sensor chamber 60 in FIG. 12 includes, as an example, four passages, each with one sensor element disposed in the cross-sectional direction; however, the number of passages and the number of sensor elements in the cross-sectional direction are not limited to this. FIG. 13 shows a cross-sectional view of a sensor chamber 60a. The sensor chamber 60a includes, as an example, two passages (passages 61a and 62a). The cross-sectional direction of the passage 61a includes two sensors (i.e., sensor element 31 and sensor element 31c). Also, in the sensor chamber 60a, as described above, the sensor elements may be disposed not only on the substrate 630 but also in two or more locations, including the substrate 630, the sidewall 610a, the sidewall 613a, and the ceiling 621a. The arrangement of the sensor elements in the passage 62a is similar to that in the passage 61a.

[0182] The material of the inner surface of the sensor chamber 60 is preferably a material that is inactive to odorants, similar to the target sample receiving portion 50. Examples of inactive materials include glass, metal, and resin. When metal is used, stainless steel (SUS) is preferable, and when resin is used, fluorine-based resin, polypropylene (PP), polyethylene (PE), ABS resin, and polyethylene terephthalate (PET) are preferable. When the material of the inner surface of the sensor chamber 60 is a material that adsorbs odorants contained in the first gas, adsorption of the odorants into the sensor chamber may reduce the amount of change in output from the sensor element in subsequent measurements, potentially preventing the odor measuring device 100c from performing accurate measurements.

[0183] The sensor elements of the sensor element group 31A may include a thin film. As an example, the odorant receiving layer 315 in Figures 2 and 3 is a thin film.

[0184] One possible mode for sending the first gas containing an odorant 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 the gas, thereby sending the odorant into the sensor chamber 60 from the gas supply port 601 side of the sensor chamber 60. However, if the sensor elements 31 and 31b have thin films, negative pressure within the sensor chamber 60 may cause the thin films to expand, preventing the sensor elements 31 and 31b from outputting stable measurement results. In the odor measurement device 100c according to this embodiment, the gas supply unit 80 pushes the gas from the first port 501 side of the sensor chamber 60 and the target sample receiving unit 50 to send the first gas into the sensor chamber 60, so the pressure within the sensor chamber 60 is positive. Therefore, the odor measurement device 100c can obtain stable measurement results even if the sensor elements of the sensor element group 31A have thin films.

[0185] The thin film of the sensor element of the sensor element group 31A may contain a filler, a resin composition, and a surfactant. Specific aspects of the sensor element will be described later.

[0186] [Sensor element] The odor measuring device 100b of embodiment 2 includes two sensor elements 31, 31b. In embodiment 2, the variation in the shape, area, and thickness of the odorant receiving layers 315, 315b of the sensor elements is not specifically specified, but it is preferable that the shape, area, and thickness of the odorant receiving layers 315, 315b each have little variation. This is because if there is variation in the shape, area, and thickness of the odorant receiving layers of multiple sensor elements, it may be difficult to stably measure the odorant. Hereinafter, the odorant receiving layers will be collectively referred to as "odorant receiving layer."

[0187] The sensor elements 31 and 31b of the second embodiment each include a first metal wiring 313A and a second metal wiring 313B as electrodes, with the metal wirings arranged parallel to each other (see FIG. 2). The sensor elements 31 and 31b of the second embodiment also include an odorant receiving layer 315 that fills the area between the first metal wiring 313A and the second metal wiring 313B. The sensor element group 31A may include, in addition to the sensor elements 31 and 31b, sensor elements that have different metal wiring (i.e., electrode) arrangements and odorant receiving layer shapes than the sensor elements 31 and 31b. Note that what was referred to as the metal wiring 313 in the first and second embodiments will hereinafter also be referred to as the electrode 313.

[0188] The sensor element comprises an electrode 313 disposed on a substrate 311 and an odorant receiving layer formed on the electrode 313. The odorant receiving layer is circular or strip-shaped. When the odorant receiving layer is circular, the diameter R of the circle may be 0.2 mm or more and 10 mm or less. When the odorant receiving layer is strip-shaped, the width W of the strip in the short direction may be 0.2 mm or more and 10 mm or less. Here, strip-shaped refers to a surface shape having a width in the short direction and a length in the long direction. When the odorant receiving layer is circular, the diameter R of the circle is preferably 1.5 mm or more and 2.7 mm or less. When the odorant receiving layer is strip-shaped, the width W of the strip in the short direction is preferably 1.5 mm or more and 2.7 mm or less.

[0189] By having the diameter R or width W of the circle of the odorant receiving layer of the sensor element included in the sensor element group 31A within the above-mentioned range, the odor measuring device 100c can stably perform measurements according to the odorant.

[0190] If the diameter R of the odorant receiving layer is less than 0.2 mm or the width W is less than 0.2 mm, the area for receiving the odorant becomes small, and the odor measuring device 100c cannot perform measurements stably.

[0191] Furthermore, if the diameter R of the odorant receiving layer is greater than 10 mm or the width W is greater than 10 mm, the area of ​​each sensor element becomes larger, and the size of the sensor chamber 60 containing the sensor element group 31A becomes larger. If the size of the sensor chamber 60 becomes larger, it becomes difficult to uniformly diffuse the first gas containing the odorant within the sensor chamber 60, and therefore the odor measuring device 100c cannot perform stable measurements.

[0192] FIG. 14 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 includes electrodes 313 (first electrode 313C, second electrode 313D) arranged on a substrate 311 and a circular odorant receiving layer 315c formed on the electrode 313. The diameter R of the odorant receiving layer 315c is 0.2 mm or more and 10 mm or less. In FIG. 14, the shape of the odorant receiving layer 315c included in the sensor element 31c is elliptical as an example, but is not limited thereto. When the shape of the odorant receiving layer 315c is elliptical, the average of the minor axis and the major axis may be 0.2 mm or more and 10 mm or less. The shape of the odorant receiving layer 315c may also be a perfect circle.

[0193] 15 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 electrodes 313 (first electrode 313C, second electrode 313D) arranged on a substrate 311, and a strip-shaped odorant receiving layer 315d formed on the electrodes 313. The length of the width in the short direction of the odorant receiving layer 315d is 0.2 mm or more and 10 mm or less.

[0194] By having the above configuration, the instability of the measurement result output that can be caused by variations in the shape and area of ​​the odorant receiving layer of each sensor element is reduced, and the odor measuring device 100c can measure odorants with high accuracy.

[0195] The sensor element group 31A may include a plurality of sensor elements other than the sensor elements 31a to 31d. In Fig. 10, the sensor element group 31A includes 16 sensor elements as an example, but the number of sensor elements is not limited to this.

[0196] The odorant receiving layers of the multiple sensor elements included in the sensor element group 31A may each contain a filler, a resin composition, and a surfactant.

[0197] The odorant receiving layers of the multiple sensor elements included in the sensor element group 31A may each have a different content ratio of filler, resin composition, and surfactant. If the content ratio of filler, resin composition, and surfactant contained in the odorant receiving layers differs, the sensitivity and detection specificity of the sensor element to the odorant will also differ.

[0198] As described above, the odor measuring device 100c is capable of detecting a wide variety of odor substances by having multiple sensor elements each having an odorant receiving layer with a different content ratio of filler, resin composition, and surfactant.

[0199] The odorant receiving layer of the sensor element included in the odor measuring device 100c according to this embodiment may have a thickness of 0.1 μm or more and 1000 μm or less. The thickness of each odorant receiving layer may preferably be 1 μm or more and 100 μm or less.

[0200] By having the thickness of the odorant receiving layer of the sensor element within the above range, the instability of the measurement result output that may be caused by variations in the thickness of the odorant receiving layer of each sensor element is reduced, and the odor measuring device 100c can measure odorants with high accuracy.

[0201] If the thickness of the odorant receiving layer is less than 0.1 μm, the value will be close to the particle diameter of the filler dispersed within the odorant receiving layer, making it impossible to ensure uniformity in the thickness of the odorant receiving layer, and there is a risk that the odor measuring device 100c will not be able to output stable measurement results. On the other hand, if the thickness of the odorant receiving layer is greater than 1000 μm, the odorant will take longer to diffuse within the odorant receiving layer, making it difficult for the odor measuring device 100c to measure the odorant with high accuracy.

[0202] By having the thickness of the odorant receiving layer of the sensor element within the above range, the instability of the measurement result output that may be caused by variations in the thickness of the odorant receiving layer of each sensor element is reduced, and the odor measuring device 100c can measure odorants with high accuracy.

[0203] The electrodes of the sensor elements included in the sensor element group 31A each have a first electrode and a second electrode, and the first and second electrodes may be arranged in the form of parallel lines, parallel curves, a comb shape, or concentric circles. Regardless of the shape adopted, the first and second electrodes are preferably arranged in line symmetry or point symmetry with each other. By arranging the first and second electrodes in this manner, the odor measurement device 100c can measure odor substances contained in gas with high accuracy.

[0204] The sensor element 31c in Fig. 14 has a first electrode 313C and a second electrode 313D. Furthermore, as an example, the first electrode 313C is composed of a metal wiring 313a and a metal wiring 313b, and the two metal wirings are arranged in a T-shape so that they are perpendicular to each other. Similarly to the first electrode 313C, the second electrode 313B is also composed of two metal wirings 313c and 313d, and the two metal wirings are arranged in a T-shape so that they are perpendicular to each other. Furthermore, the first electrode 313A and the second electrode 313B are arranged in parallel lines so that the metal wiring 313a and the metal wiring 313c face each other.

[0205] The first electrode 313C and the second electrode 313D are particularly arranged in a T-shape, which allows the first electrode 313C and the second electrode 313D to be located at a suitable distance, thereby stabilizing the electrode resistance. For example, if the electrodes were arranged in a comb shape, the distance between the electrodes would be too short, which could result in the electrode resistance being too low. Furthermore, the first electrode 313C and the second electrode 313D are arranged in a T-shape, which allows the slurry to spread easily in the application process of the sensor element manufacturing method described below, since there are no uneven portions of the electrode that could hinder the slurry from spreading. Furthermore, the ease of spreading the slurry also contributes to a consistent thickness of the odorant receiving layer after drying.

[0206] [Method for Manufacturing Sensor Element] A manufacturing method for manufacturing multiple types of sensor elements used in the odor measurement device 100c is described below. The odorant receiving layer of the sensor element can be made from slurries with various compositions, but the viscosity of each slurry varies depending on the slurry composition. When forming an odorant receiving layer by applying slurries with different viscosities using the same method, for example, a low-viscosity slurry will easily wet and spread on the substrate, while a high-viscosity slurry will not wet and spread on the substrate as easily. Thus, when applying slurries with different viscosities using the same manufacturing method, variations in the shape, area, and thickness of the odorant receiving layer after drying occur. Sensor elements manufactured using such odorant receiving layers have difficulty in stably measuring odorants. On the other hand, changing the manufacturing method depending on the viscosity of the slurry will result in a uniform odorant receiving layer without variations in shape, area, and thickness, but will increase manufacturing costs.

[0207] According to the manufacturing method of this embodiment, it is possible to manufacture multiple types of sensor elements with little variation in shape, area, and thickness even when using slurries with different compositions, i.e., different viscosities. Furthermore, since it is not necessary to change the manufacturing method depending on the viscosity, manufacturing costs can be reduced.

[0208] FIG. 16 is a flowchart illustrating steps in a manufacturing method for manufacturing a plurality of types of sensor elements used in the odor measuring device 100c.

[0209] <Slurry Preparation Step> First, multiple types of slurries with different mixing ratios of polyvinyl acetal, surfactant, and filler are prepared. The mixing ratio of polyvinyl acetal, surfactant, and filler can be appropriately set depending on the desired sensitivity and detection specificity of the odorant receiving layer. The slurry may contain solvents and additives in addition to polyvinyl acetal, surfactant, and filler (S21).

[0210] <Electrode Arrangement Step> Next, electrodes are arranged on the substrate (S22). The electrodes may include a first electrode and a second electrode. The first electrode and the second electrode may be arranged in parallel straight lines, parallel curves, a comb shape, or a concentric circle shape. Regardless of the shape of the first electrode and the second electrode, it is preferable that they are arranged in line symmetry or point symmetry with each other. By arranging the first electrode and the second electrode in this manner, the odor measuring device 100c can measure odor substances contained in gas with high accuracy.

[0211] As an example, in Figures 14 and 15, one set of electrodes (first electrode 313C and second electrode 313D) is arranged on one substrate 311, but multiple sets of electrodes may be arranged side by side on one substrate.

[0212] <Area Defining Step> Next, coating areas onto which each of the multiple types of slurries is to be applied are defined on the substrate on which the electrodes are disposed (S23). The coating areas may be defined, for example, by applying a resist. Furthermore, if the slurry is dropped from a nozzle in the coating step, the coating areas may be defined to match the nozzle diameter. Figure 17 is a schematic diagram of the substrate 311 after the resist M has been applied. The resist M is applied so as to define a coating area 330. In the coating area 330, the substrate 311 is exposed.

[0213] The size of the coating area 330 may be set to be the same for each of the multiple types of slurries. That is, even if the slurries have different mixture ratios of filler, resin composition, and surfactant, the area of ​​the coating area 330 for applying the slurries may be uniform. This reduces the variation in the area of ​​the multiple odorant receiving layers after drying, even when multiple types of slurries with different mixture ratios, i.e., different viscosities, are used.

[0214] 17 is circular as an example, but the shape of the coating area 330 is not limited to this. The shape of the coating area 330 may be circular or strip-shaped. This results in the formation of a circular or strip-shaped odorant receiving layer.

[0215] When the shape of the applied area 330 is circular, the diameter of the circle may be 0.2 mm or more and 10 mm or less, and when the shape of the applied area 330 is strip-shaped, the length of the strip in the short direction may be 0.2 mm or more and 10 mm or less. This forms a circular odorant receiving layer with a diameter of 0.2 mm or more and 10 mm or less, or a circular odorant receiving layer with a strip-like length in the short direction.

[0216] The method for applying the resist M is not particularly limited, but examples include a method of silk-screening the solder resist in a specified area and then UV-curing the solder resist, a method of attaching a resist film to a substrate, and a method of curing only the resist in a specified area and removing the uncured portion.

[0217] <Coating Step> Subsequently, each of the plurality of types of slurry is coated onto the coating region 330 (S24). The method for coating the slurry may be a conventionally known method, and the slurry may be dropped from a nozzle, sprayed, or spin-coated.

[0218] The viscosities of the multiple types of slurries are different. The different viscosities of the slurries are caused, for example, by different mixing ratios of the filler, resin composition, and surfactant. Slurries with different viscosities may exhibit different wetting and spreading behavior. However, in the coating step of this manufacturing method, the coating area is defined in the previous area defining step, so the slurry is applied to the defined area.

[0219] <Drying process> Finally, the slurry applied to the application area 330 is dried to form an odorant receiving layer (S25). The method for drying the slurry is not particularly limited, but for example, it can be heated at 100°C for 1 hour at normal pressure, and then heated at 100°C for 1 hour while reducing the pressure in a vacuum dryer.

[0220] In the drying process, the thickness of the odorant receiving layer after drying may be 0.1 μm or more and 1000 μm or less. The thickness of the odorant receiving layer after drying may preferably be 1 μm or more and 100 μm or less. If the thickness of the odorant receiving layer is within the above range, the sensor element can stably measure odorants. If the thickness of the odorant receiving layer is less than 0.1 μm, the value will be close to the particle diameter of the filler dispersed in the odorant receiving layer, so the uniformity of the thickness of the odorant receiving layer cannot be guaranteed, and the odor measuring device 100c may not be able to output stable measurement results. On the other hand, if the thickness of the odorant receiving layer is greater than 1000 μm, the diffusion time of the odorant within the odorant receiving layer will be longer, making it difficult for the odor measuring device 100c to measure odorants with high accuracy.

[0221] As described above, the manufacturing method according to this embodiment includes a slurry preparation process, an electrode placement process, an area definition process, a coating process, and a drying process. By adopting this manufacturing method, it is possible to manufacture multiple types of sensor elements with little variation in the shape, area, and thickness of the odorant receiving layer, even when using multiple types of slurries with different mixing ratios of filler, resin composition, and surfactant. Furthermore, since there is no need to change the manufacturing method depending on the viscosity of the slurry, manufacturing costs can be reduced.

[0222] In particular, by defining the coating area in the area defining step, the wetting and spreading of the slurry droplets in the subsequent coating step is improved. For example, if the coating area is defined by resist, the surface roughness of the substrate will differ between the area where the resist is present and the area where the resist is not present. In the area where the resist is not present, the substrate is exposed, resulting in a high surface roughness and a low surface tension. This allows the wetting and spreading of the slurry droplets to be improved in the coating area where the substrate is exposed.

[0223] In addition, by arranging the coating area in the area definition process, the wetting and spreading of the slurry in the subsequent coating process is regulated, and the positional relationship between the odorant receiving layer and the electrode is constant. For example, if the coating area is defined by resist, a step is created at the resist boundary, which regulates the wetting and spreading of the slurry, and the positional relationship between the odorant receiving layer and the electrode is constant.

[0224] In addition, in this embodiment, the odorant receiving layer 315 is formed by coating the aforementioned resin composition. As described above, the resin composition has excellent compositional stability and coating stability, so it is possible to reduce the variation in performance between the odorant receiving layers 315 when multiple odorant receiving layers 315 are produced.

[0225] In addition, when preparing the odorant receiving layer, the odorant receiving layer may be prepared by coating a resin composition, and then an electrode may be prepared so as to be in contact with the odorant receiving layer.

[0226] [Software Implementation Example] The control block (particularly the control unit 1) of the estimation devices 10, 10a, and 10b may be implemented by a logic circuit (hardware) formed on an integrated circuit (IC chip) or the like, or may be implemented by software.

[0227] In the latter case, the estimation devices 10, 10a, and 10b each include a computer that executes instructions from a program, which is software that realizes each function. The computer includes, for example, one or more processors and a computer-readable recording medium storing the program. The object of the present invention is achieved by the processor reading and executing the program from the recording medium. The processor may be, for example, a central processing unit (CPU). The recording medium may be a "non-transitory tangible medium," such as a read-only memory (ROM), tape, disk, card, semiconductor memory, or programmable logic circuit. The device may also include a random access memory (RAM) for storing the program. The program may be supplied to the computer via any transmission medium capable of transmitting the program (such as a communication network or broadcast waves). Note that one aspect of the present invention may also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

[0228] Furthermore, some or all of the functions of the control blocks can be realized by logic circuits. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of the present invention. In addition, the functions of the control blocks can also be realized by, for example, a quantum computer.

[0229] Furthermore, each process described in each of the above embodiments may be executed by AI (Artificial Intelligence). In this case, the AI ​​may run on the control device or on another device (for example, an edge computer or a cloud server).

[0230] [Summary] As is clear from the above explanation, the resin composition of aspect 1 of the present disclosure is a resin composition for an odorant receiving layer, which contains at least polyvinyl acetal (A) and a filler (C), wherein the content of the filler (C) is 40 to 85 weight % relative to 100 weight % of the total of the polyvinyl acetal (A) and filler (C), and when the resin composition further contains surfactant (B), the content of the surfactant (B) is 2 weight parts or less relative to 100 weight parts of polyvinyl acetal (A).

[0231] In the resin composition according to Aspect 2 of the present disclosure, in Aspect 1, the filler (C) may be a conductive filler.

[0232] In the resin composition according to Aspect 3 of the present disclosure, in Aspect 1 or 2, the filler (C) may be one or more selected from the group consisting of carbon black, graphite, and carbon nanotubes.

[0233] In the resin composition according to Aspect 4 of the present disclosure, in any one of Aspects 1 to 3, the polyvinyl acetal (A) may be polyvinyl butyral.

[0234] The resin composition according to aspect 5 of the present disclosure may be substantially free of surfactant (B) in any of aspects 1 to 4.

[0235] In the resin composition according to Aspect 6 of the present disclosure, in any one of Aspects 1 to 5, the filler (C) has a specific surface area of ​​100 cm ２ / g or less.

[0236] In the resin composition according to Aspect 7 of the present disclosure, in any one of Aspects 1 to 6, the degree of acetalization of the polyvinyl acetal (A) may be 60 to 70 mol%.

[0237] The sensor element of aspect 8 of the present disclosure is a sensor element comprising an odorant receiving layer containing a resin composition described in any of aspects 1 to 7, a first metal wiring, and a second metal wiring, wherein the first metal wiring and the second metal wiring are spaced apart, and the odorant receiving layer is in contact with at least a portion of the first metal wiring and at least a portion of the second metal wiring.

[0238] An odor sensor according to aspect 9 of the present disclosure comprises at least one sensor element as described in aspect 8, a power source for powering the sensor element, and a measuring device for outputting a measurement value indicating the electrical conductivity of the odorant receiving layer of the sensor element powered by the power source.

[0239] In the odor sensor according to Aspect 10 of the present disclosure, in Aspect 9, the power source may supply a constant current or apply a constant voltage to the at least one sensor element.

[0240] An odor measurement device according to aspect 11 of the present disclosure is an odor measurement device comprising the odor sensor described in aspect 9 or 10, and an estimation device, wherein the estimation device comprises an acquisition unit that acquires the measurement values ​​from the measuring device, an analysis unit that analyzes the change in electrical conductivity of the at least one sensor element over time, and an estimation unit that estimates odor substances based on an estimation model, and the estimation model is generated by machine learning using training data that includes a combination of measurement values ​​measured by the measuring device when each of a plurality of odor substances is adsorbed onto the at least one sensor element and identification information unique to the odor substance that provided the measurement values.

[0241] The odor control program according to aspect 12 of the present disclosure is a control program for causing a computer to function as the odor measurement device described in aspect 11, and causes the computer to function as the acquisition unit, the analysis unit, and the estimation unit.

[0242] The present invention will be further explained below with reference to examples and comparative examples, but the present invention is not limited thereto. Unless otherwise specified, % means % by weight and parts means parts by weight.

[0243] [Materials] <Polyvinyl acetal (A)> Polyvinyl butyral (A-1) (degree of acetalization: 63 mol%) (S-LEC (registered trademark) BL-1, manufactured by Sekisui Chemical Co., Ltd.) Polyvinyl formal (A-2) (degree of acetalization: 60 mol%) <Dispersant (B)> Polyether phosphate ester amine (B-1) (Disparlon DA325, manufactured by Kusumoto Chemical Co., Ltd.) Polyvinylpyrrolidone (B-2) (Polyvinylpyrrolidone K90, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) <Filler (C)> Carbon black (C-1) (specific surface area 50 cm ３ / g) (Tokai Carbon Co., Ltd., Toka Black #4400) Carbon black (C-2) (specific surface area 225 cm ３ / g) (Tokai Carbon Co., Ltd., Toka Black #5500) Titanium powder (C-3) (Fujifilm Wako Pure Chemical Industries, Ltd.) Silica powder (C-4) (Fujifilm Wako Pure Chemical Industries, Ltd.) [Examples 1 to 7, 14 to 15, Comparative Examples 1 to 4] <Preparation of Polyvinyl Formal (A-2)> 88 g of polyvinyl alcohol (Fujifilm Wako Pure Chemical Industries, Ltd.) was dissolved in 1,300 g of pure water by heating. After cooling the solution to 20°C, 93 g of 35% hydrochloric acid and 81 g of 37% aqueous formaldehyde solution were added and reacted for 4 hours. After the reaction, 90 g of sodium bicarbonate was added to the solution for neutralization. Thereafter, the precipitated powder was collected by filtration, washed with water, and dried to obtain polyvinyl formal (A-2). After dissolving in deuterated dimethyl sulfoxide, １ H-NMR measurement revealed that the degree of acetalization of polyvinyl formal (A-2) was 60 mol %.

[0244] <Preparation of Slurry> Polyvinyl acetal (A), dispersant (B), and filler (C) were weighed into a container in the amounts shown in Table 1 and mixed with N-methylpyrrolidone as a solvent to obtain a mixture. The mixture was stirred at 2000 rpm for 10 minutes using a planetary centrifugal mixer (ARE-310, manufactured by Thinky Corporation) to obtain a slurry. The slurry was used as a resin composition for forming an odorant-receiving layer.

[0245] [Measurement of ΔV Variation Coefficient 1] Eight substrates with 4 mm long Cu wires arranged in parallel at 1 mm intervals were fixed to a tabletop applicator (IMAGE MASTER 350PC, manufactured by Musashi Engineering, Inc.). 0.50 μL of each of the resin compositions of Examples 1-7, 14-15, and Comparative Examples 1-3 described above was dropped between the Cu wires on each substrate. After dropping, the resin compositions were dried for one hour in a free-flow dryer heated to 100°C, and then further dried under reduced pressure at 100°C for one hour. In this way, eight sensor elements were obtained for each Example and Comparative Example, each having an odorant-receiving layer formed from the resin composition between the two Cu wires, each of which was in contact with the other. These eight sensor elements were used as chemiresistor-type odor sensors, and measurements were performed.

[0246] A predetermined amount of nitrogen gas and a predetermined amount of ethanol or hexane to achieve a concentration of 100 ppm were placed in a gas bag as sample gases and completely vaporized within the gas bag. For each of the odor sensors in Examples 1-7, 14-15, and Comparative Examples 1-4, nitrogen as a carrier gas was introduced from the gas inlet into the housing containing the sensor element at a flow rate of 1 L / min using a gas flow regulator and discharged to the outside. Subsequently, each sample gas was introduced at a flow rate of 1 L / min and discharged to the outside. During this time, the measurements of the voltmeter connected to the sensor element were recorded by a computer. Thus, the voltage values ​​of each of the eight sensor elements in the odor sensor were measured. For each sensor element of each odor sensor, the maximum value ΔV of the difference between the output voltage V0 during nitrogen gas introduction and the voltage V during sample gas introduction was calculated. The standard deviation σ and mean value μ of the eight maximum ΔV data obtained for each odor sensor were then calculated, and the ΔV variation coefficient (= σ / μ) of the resin composition forming the sensor element was determined.

[0247] [Results 1] The results are shown in Table 1.

[0248]

[0249] As can be seen from Table 1, all of the odor sensors according to the Examples had a low ΔV coefficient of variation of 0.19 or less, indicating excellent manufacturing stability. Furthermore, all of the odor sensors according to the Examples had a ΔV ratio of 5.0 or more, indicating excellent odor discrimination performance. On the other hand, the odor sensor of Comparative Example 1, which did not contain a surfactant, had a high ΔV coefficient of variation of 0.22 or more, indicating poor manufacturing stability. Comparative Examples 2 to 4, which contained more than 2 parts by weight of dispersant per 100 parts by weight of (A), had low ΔV coefficients of variation, but all had ΔV ratios below 5.0, indicating poor odor discrimination performance.

[0250] [Measurement of ΔV Variation Coefficient 2] Eight parallel-arranged piezoelectric elements were fixed to a tabletop applicator (IMAGE MASTER 350PC, manufactured by Musashi Engineering Co., Ltd.). 0.50 μL of each of the resin compositions of Examples 8 to 13 was dropped onto the membrane-type surface stress sensor (MSS) on each substrate. After dropping, the resin compositions were dried for 1 hour in a forward-air dryer heated to 100°C, and then further dried under reduced pressure at 100°C for 1 hour. In this way, eight sensor elements were obtained, each having an odorant-receiving layer formed on the MSS using the resin compositions of Examples 8 to 13. These eight sensor elements were used as membrane-type surface stress-type odor sensors, and measurements were performed.

[0251] Instead of the sensor element, the output voltage V ０ The standard deviation σ and average value μ of the eight maximum ΔV data obtained by each odor sensor were calculated in the same manner as in [Measurement of ΔV Variation Coefficient 1] except that ΔV and V were the outputs from the piezoelectric element, and the ΔV variation coefficient (=σ / μ) of the resin composition forming the sensor element was determined.

[0252] [Results 2] The results are shown in Table 2.

[0253]

[0254] As can be seen from Table 2, all of the odor sensors had a ΔV of 0.19 or less, indicating high manufacturing stability, and a ΔV ratio of 9.0 or more, indicating excellent odor discrimination performance.

[0255] The present invention is useful as an odor identification sensor for medical, gas detection, agricultural, and other industrial and daily uses. For example, farmers can use the odor identification sensor to determine the maturity of fragrant crops and manage optimal harvest timing. Furthermore, the odor identification sensor can also be used to digitize the odors of products such as food and cosmetics, helping to improve the efficiency of product development and stabilize quality.

[0256] 10, 10a, 10b Estimation device 11 Measurement value acquisition unit (acquisition unit) 12 Change pattern analysis unit (analysis unit) 16 Estimation unit 30, 30b Odor sensor 31, 31b, 31c, 31d Sensor element 32, 32b Constant current source (power supply) 33, 33b Voltmeter (measuring instrument) 100, 100a, 100b, 100c Odor measurement device 313A First metal wiring 313B Second metal wiring 315, 315b Odor substance receiving layer 313C First electrode 313D Second electrode 330 Coating area

Claims

1. A resin composition for an odorant receiving layer, containing at least polyvinyl acetal (A) and a filler (C), wherein the content of the filler (C) is 40 to 85% by weight relative to 100% by weight of the total of the polyvinyl acetal (A) and the filler (C), and when the resin composition further contains a surfactant (B), the content of the surfactant (B) is 2 parts by weight or less relative to 100 parts by weight of the polyvinyl acetal (A).

2. The resin composition according to claim 1, wherein the filler (C) is a conductive filler.

3. The resin composition according to claim 1 or 2, wherein the filler (C) is at least one selected from the group consisting of carbon black, graphite, and carbon nanotubes.

4. The resin composition according to any one of claims 1 to 3, wherein the polyvinyl acetal (A) is polyvinyl butyral.

5. The resin composition according to any one of claims 1 to 4, which is substantially free of surfactant (B).

6. The filler (C) has a specific surface area of ​​100 cm ２ / g or less, and is one or more types selected from the group consisting of graphite and carbon nanotubes.

7. The resin composition according to any one of claims 1 to 6, wherein the degree of acetalization of the polyvinyl acetal (A) is 60 to 70 mol %.

8. A sensor element comprising an odorant receiving layer containing the resin composition described in any one of claims 1 to 7, a first metal wiring, and a second metal wiring, wherein the first metal wiring and the second metal wiring are spaced apart, and the odorant receiving layer is in contact with at least a portion of the first metal wiring and at least a portion of the second metal wiring.

9. An odor sensor comprising: at least one sensor element as described in claim 8; a power source for supplying power to the sensor element; and a measuring device for outputting a measurement value indicating the electrical conductivity of the odorant receiving layer of the sensor element supplied with power from the power source.

10. The odor sensor according to claim 9, wherein the power source supplies a constant current or applies a constant voltage to the at least one sensor element.

11. An odor measuring device comprising the odor sensor and estimation device described in claim 9 or 10, wherein the estimation device comprises: an acquisition unit that acquires the measurement values ​​from the measurement device; an analysis unit that analyzes changes in the electrical conductivity of the at least one sensor element over time; and an estimation unit that estimates odor substances based on an estimation model, wherein the estimation model is generated by machine learning using learning data that includes a combination of measurement values ​​measured by the measurement device when each of a plurality of odor substances is adsorbed onto the at least one sensor element and identification information unique to the odor substances that provided the measurement values.

12. A control program for causing a computer to function as the odor measuring device according to claim 11, the control program causing a computer to function as the acquisition unit, the analysis unit, and the estimation unit.

Images