Gas detector

Abstract

This invention provides a gas detector that can improve detection sensitivity when detecting a gas containing a substance by utilizing a sensitive element that undergoes volume expansion upon adsorption of the substance. [Solution] The gas detector 1 comprises a base material 2 having a support surface 21, a sensing part 4 disposed on the support surface 21 of the base material 2, a first conductor 31 and a second conductor 32, and a restricting part 5. The first conductor 31 has a first terminal portion 312. The second conductor 32 has a second terminal portion 322 disposed at a distance from the first terminal portion 312. The sensing part 4 has the property of undergoing volume expansion by adsorbing at least one type of substance. Each of the first terminal portion 312 and the second terminal portion 322 is in contact with the sensing part 4. The restricting part 5 is fixed to the base material 2 and, by being in contact with the sensing part 4, restricts the expansion of the sensing part 4 in at least one direction other than the direction in which the first terminal portion 312 and the second terminal portion 322 are aligned.

Description

Technical Field

[0001] The present disclosure relates to a gas detector, and more particularly to a gas detector including a sensing part that causes volume expansion by adsorbing at least one substance contained in a gas.

Background Art

[0002] Patent Document 1 discloses a gas sensor for detecting a gas containing a volatile organic compound, including a substrate, a first conductor and a second conductor disposed on the substrate, an organic adsorbent capable of adsorbing the gas, an adsorbent layer in contact with each of the first conductor and the second conductor, and a first wall portion surrounding the surface of the substrate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present disclosure is to provide a gas detector capable of improving detection sensitivity when detecting a gas containing a substance by using a sensing part that causes volume expansion by adsorbing the substance.

Means for Solving the Problems

[0005] A gas detector according to one aspect of the present disclosure comprises a substrate having a support surface, a sensing portion disposed on the support surface of the substrate, a first conductor and a second conductor, and a restricting portion. The first conductor has a first terminal portion. The second conductor has a second terminal portion disposed at a distance from the first terminal portion. The sensing portion has the property of undergoing volume expansion by adsorbing at least one substance. Each of the first and second terminal portions is in contact with the sensing portion. The restricting portion is fixed to the substrate and, by being in contact with the sensing portion, restricts the expansion of the sensing portion in at least one direction other than the direction in which the first and second terminal portions are aligned. [Effects of the Invention]

[0006] According to one aspect of this disclosure, when detecting a gas containing a substance by utilizing a sensitive part that undergoes volume expansion upon adsorption of the substance, the detection sensitivity can be improved. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a plan view showing the substrate, first conductor, and second conductor in a gas detector according to the first embodiment. [Figure 2] Figure 2 is a plan view showing the substrate, first conductor, second conductor, and sensing element of the gas detector described above. [Figure 3] Figure 3 is a plan view of the gas detector shown above. [Figure 4] Figure 4 is a front view of the gas detector shown above. [Figure 5] Figure 5 is a side view of the gas detector shown above. [Figure 6] Figure 6 is a cross-sectional view of the gas detector according to the second embodiment. [Figure 7] Figure 7 is a plan view of the gas detector according to the third embodiment. [Figure 8] Figure 8 is a front view of the gas detector shown above. [Modes for carrying out the invention]

[0008] Embodiments and modifications will be described with reference to the drawings. Note that the embodiments and modifications described below are only a part of the various embodiments of this disclosure. Furthermore, the embodiments and modifications described below can be modified in various ways depending on the design, etc., as long as the objectives of this disclosure are achieved. It is also possible to combine the configurations of the modifications as appropriate. The figures referenced below are all schematic diagrams, and the dimensional ratios of the components in the figures do not necessarily reflect the actual dimensional ratios.

[0009] 1. Overview The gas detector 1 of this embodiment comprises a base material 2 having a support surface 21, a sensing part 4 disposed on the support surface 21 of the base material 2, a first conductor 31 and a second conductor 32, and a restricting part 5. The first conductor 31 has a first terminal portion 312. The second conductor 32 has a second terminal portion 322 disposed at a distance from the first terminal portion 312. The sensing part 4 has the property of undergoing volume expansion by adsorbing at least one substance. Each of the first terminal portion 312 and the second terminal portion 322 is in contact with the sensing part 4. The restricting part 5 is fixed to the base material 2 and, by being in contact with the sensing part 4, restricts the expansion of the sensing part 4 in at least one direction other than the direction in which the first terminal portion 312 and the second terminal portion 322 are aligned.

[0010] Furthermore, restricting the expansion of the sensing element 4 means preventing the sensing element 4 from expanding, or reducing the amount of expansion of the sensing element 4 to what it would be if the restricting element 5 were not present.

[0011] According to the embodiment, when the sensing part 4 adsorbs a substance in the gas, it expands, which can change its electrical properties, such as electrical resistance. By detecting this change in the electrical properties of the sensing part 4 using the first conductor 31 and the second conductor 32, the substance in the gas can be detected. In the embodiment, the restricting part 5 restricts the expansion of the sensing part 4 in at least one direction other than the direction in which the first terminal portion 312 and the second terminal portion 322 are aligned, thereby increasing the amount of volume expansion of the sensing part 4 in the direction in which the first terminal portion 312 and the second terminal portion 322 are aligned when the sensing part 4 adsorbs a substance in the gas. As a result, the degree of change in the electrical properties of the sensing part 4 in the direction in which the first terminal portion 312 and the second terminal portion 322 are aligned becomes larger, and thus the sensitivity of substance detection based on the change in electrical properties can be increased.

[0012] 2.1. First Embodiment The gas detector 1 of the first embodiment will be described with reference to Figures 1 to 5.

[0013] The gas detector 1 is designed to detect at least one substance contained in a gas. Examples of substances that can be detected include flammable gases such as methane, propane, and butane; toxic gases such as ammonia, hydrogen sulfide, and carbon monoxide; and volatile organic compounds (VOCs). However, the substances to be detected are not limited to those mentioned above. The substances to be detected may also include substances that stimulate the human sense of smell (so-called odor components). The gas detector 1 can detect VOCs and the like contained in sample gases such as gas collected from food, breath collected from the human body, or air collected from a room in a building.

[0014] The gas detector 1 comprises a base material 2, a sensing unit 4, a first conductor 31 and a second conductor 32, and a regulating unit 5.

[0015] The base material 2 is an electrically insulating substrate, such as a resin substrate or a ceramic substrate. The base material 2 has a support surface 21 that faces in the direction of its thickness.

[0016] In the first embodiment, both the first conductor 31 and the second conductor 32 are arranged on the support surface 21 of the base material 2. The first conductor 31 and the second conductor 32 are conductor wirings made of a metal such as copper, for example.

[0017] The first conductor 31 has a first line portion 311 and a first terminal portion 312 connected to the first line portion 311. The second conductor 32 has a second line portion 321 and a second terminal portion 322 connected to the second line portion 321.

[0018] The first line portion 311 is linear. The second line portion 321 is a long straight line along the longitudinal direction of the first line portion 311. The first line portion 311 and the second line portion 321 are arranged side by side with a gap in a direction orthogonal to the longitudinal direction of the first line portion 311.

[0019] The first conductor 31 has a plurality of first terminal portions 312. The plurality of first terminal portions 312 are arranged at intervals along the longitudinal direction of the first line portion 311. Each of the plurality of first terminal portions 312 is a long straight line along a direction orthogonal to the longitudinal direction of the first line portion 311. The plurality of first terminal portions 312 extend from the first line portion 311 along a direction orthogonal to the longitudinal direction of the first line portion 311 toward the second line portion 321. Therefore, the first conductor 31 has a comb-like shape.

[0020] The second conductor 32 has a plurality of second terminal portions 322. The plurality of second terminal portions 322 are arranged at intervals along the longitudinal direction of the second line portion 321. Each of the plurality of second terminal portions 322 is a long straight line along a direction orthogonal to the longitudinal direction of the second line portion 321. The plurality of second terminal portions 322 extend from the second line portion 321 along a direction orthogonal to the longitudinal direction of the second line portion 321 toward the first line portion 311. Therefore, the second conductor 32 has a comb-like shape.

[0021] The first terminal section 312 and the second terminal section 322 are arranged at intervals in one direction along the support surface 21 (along the longitudinal direction of the first line section 311 and the longitudinal direction of the second line section 321, as indicated by arrow D1 in Figure 3). Specifically, the multiple first terminal sections 312 and the multiple second terminal sections 322 are arranged alternately at intervals in the direction indicated by arrow D1 in Figure 3.

[0022] The sensing element 4 has the property of undergoing volume expansion by adsorbing at least one type of substance. When the sensing element 4 expands in volume, its electrical properties, such as its electrical resistance (electrical resistivity), change accordingly.

[0023] The sensing part 4 comprises, for example, a matrix that undergoes volume expansion by adsorbing at least one type of substance, and conductive particles dispersed in the matrix.

[0024] The matrix is ​​made from an organic material that adsorbs at least one substance. The organic material includes, for example, OV-17, OV-22, OV-25, OV-225, OV-330, SILAR-5CP, SILAR-7CP, and OV-275, manufactured by Shinwa Chemical Co., Ltd., which are column packing materials for chromatography, as well as at least one selected from the group consisting of polystyrene, poly(4-tert-butylstyrene), poly(isobutyl methacrylate), poly(butyl methacrylate), polyvinyl formal, poly(ethylene succinate), low molecular weight poly(vinylidene fluoride), and high molecular weight poly(vinylidene fluoride). However, the organic material is not limited to the above, and any material that undergoes volume expansion by adsorbing at least one substance may be used.

[0025] The conductive particles include, for example, at least one material selected from the group consisting of carbon materials, conductive polymers, metals, metal oxides, semiconductors, superconductors, and complex compounds.

[0026] When the sensing element 4 comprises a matrix and conductive particles, if a gas containing a substance that the matrix can adsorb comes into contact with the sensing element 4, the matrix in the sensing element 4 will adsorb the substance, increasing the volume of the matrix and thus increasing the distance between the conductive particles within the sensing element 4. Accordingly, the electrical resistance (electrical resistivity) of the sensing element 4 increases. The higher the concentration of the substance in the gas, the greater the amount of substance adsorbed by the matrix, and the higher the electrical resistance (electrical resistivity) of the sensing element 4. Therefore, the change in the electrical resistance of the sensing element 4 depends on the concentration of the substance in the gas.

[0027] The sensing part 4 is positioned on the support surface 21 so as to cover the first terminal portion 312 and the second terminal portion 322. In this embodiment, the sensing part 4 is film-shaped. Viewed in the thickness direction of the base material 2, the sensing part 4 is rectangular in shape, with two of the four sides of the outer circumference of the sensing part 4 aligning in the direction indicated by arrow D1, and the remaining two sides aligning in a direction perpendicular to the direction indicated by arrow D1.

[0028] The restricting portion 5 is fixed to the base material 2 and, by contacting the sensing portion 4, restricts the expansion of the sensing portion 4 in at least one direction other than the direction in which the first terminal portion 312 and the second terminal portion 322 are aligned (the direction indicated by arrow D1). In the first embodiment, the restricting portion 5 restricts the expansion of the sensing portion 4 in a direction along the support surface 21 and perpendicular to the direction indicated by arrow D1, and further restricts the expansion of the sensing portion 4 in a direction perpendicular to the support surface 21 and perpendicular to the direction indicated by arrow D1.

[0029] Specifically, the regulating section 5 has two lateral regulating sections 51 and an upper regulating section 52.

[0030] The two lateral restricting portions 51 are arranged in a direction different from the direction in which the first terminal portion 312 and the second terminal portion 322 are aligned along the support surface 21, specifically in a direction perpendicular to the direction indicated by arrow D1. The sensing portion 4 is positioned between the two lateral restricting portions 51 so as to be in contact with each of the lateral restricting portions 51. The lateral restricting portions 51 are wall-like structures that are long in the direction indicated by arrow D1, fixed to the support surface 21, and positioned to rise from the support surface 21. The two lateral restricting portions 51 are in contact with the end faces on both sides of the outer circumferential surface of the sensing portion 4 in the direction perpendicular to the direction indicated by arrow D1. Therefore, the two lateral restricting portions 51 restrict the expansion of the sensing portion 4 along the support surface 21 and in the direction perpendicular to the direction indicated by arrow D1.

[0031] The upper restricting portion 52 is formed to span between the two lateral restricting portions 51 and is in contact with the surface of the sensing portion 4 opposite to the base material 2 side. The upper restricting portion 52 and the base material 2 sandwich the sensing portion 4 in a direction perpendicular to the support surface 21, thereby restricting the expansion of the sensing portion 4 in a direction perpendicular to the support surface 21 and perpendicular to the direction indicated by arrow D1.

[0032] The restricting section 5 has an opening 59 that opens the sensing section 4 in the direction indicated by arrow D1. That is, the restricting section 5 has openings on two end faces in the direction indicated by arrow D1, each of which exposes the sensing section 4 to the outside, and these openings are the opening 59. Therefore, the restricting section 5 does not restrict the expansion of the sensing section 4 in the direction indicated by arrow D1.

[0033] There are no particular restrictions on the material of the restricting part 5, but it is preferable that it be permeable to gas. In this case, the restricting part 5 is less likely to inhibit the adsorption of gaseous substances onto the sensing part 4. Furthermore, it is preferable that the restricting part 5 be made from a material with low elasticity. In this case, the restricting part 5 can effectively restrict the expansion of the sensing part 4. Examples of materials for the restricting part 5 include porous films such as polyethylene porous films, nonwoven fabrics with low elasticity such as polyester nonwoven fabrics, and other fabrics with low elasticity. The restricting part 5 may also be made from a rigid material, in which case the restricting part 5 can effectively restrict the expansion of the sensing part 4.

[0034] When the gas detector 1 is used, for example, the first line portion 311 of the first conductor 31 and the second line portion 321 of the second conductor 32 of the gas detector 1 are connected to a measurement circuit that measures electrical characteristics such as the electrical resistance between the first conductor 31 and the second conductor 32. The arrows in the sensing unit 4 shown in Figure 3 indicate the direction of the electric field lines between the first terminal portion 312 and the second terminal portion 322. The detection results obtained using the gas detector 1 largely reflect the direction of these electric field lines in the sensing unit 4, that is, the electrical resistance in the direction in which the first terminal portion 312 and the second terminal portion 322 are aligned.

[0035] When the gas detector 1 detects a substance to be measured in a gas, the sensing part 4 is exposed to the gas, for example, by supplying gas around the sensing part 4. As a result, the sensing part 4 expands by adsorbing substances in the gas. In the first embodiment, as described above, the restricting part 5 restricts the expansion of the sensing part 4 along the support surface 21 and in a direction perpendicular to the direction indicated by arrow D1, and the expansion of the sensing part 4 in a direction perpendicular to the support surface 21 and perpendicular to the direction indicated by arrow D1, but does not restrict the expansion of the sensing part 4 in the direction indicated by arrow D1. Therefore, compared to the case where the expansion of the sensing part 4 is not restricted by the restricting part 5, the amount of increase in the electrical resistance value of the sensing part 4 in the direction indicated by arrow D1 is larger. That is, the amount of increase in the electrical resistance value of the sensing part 4 in the direction in which the first terminal portion 312 and the second terminal portion 322 are aligned is larger. For this reason, in the first embodiment, the detection sensitivity is improved compared to the case where the expansion of the sensing part 4 is not restricted by the restricting part 5.

[0036] 2.2. Second Embodiment The gas detector 1 of the second embodiment will be described with reference to Figure 6. Detailed explanations of the same configuration as in the first embodiment will be omitted as appropriate below.

[0037] In the second embodiment, the first terminal portion 312 of the first conductor 31 is positioned on the support surface 21 of the base material 2. The sensing portion 4 is positioned on the support surface 21 so as to cover the first terminal portion 312. The second terminal portion 322 of the second conductor 32 is positioned on the surface of the sensing portion 4 opposite to the base material 2 side, and opposite to the first terminal portion 312. Therefore, the first terminal portion and the second terminal portion 322 are aligned in a direction perpendicular to the support surface 21, with the sensing portion 4 interposed between them. As a result, the direction of the electric field lines between the first terminal portion 312 and the second terminal portion 322 is perpendicular to the support surface 21.

[0038] The restricting portion 5 has a wall-shaped periphery restricting portion 53 that rises from the support surface 21 of the base material 2. The periphery restricting portion 53 is formed to surround the sensing portion 4, and the inner surface of the periphery restricting portion 53 is in contact with the outer surface of the sensing portion 4. Therefore, the periphery restricting portion 53 restricts the expansion of the sensing portion 4 in the direction along the support surface 21.

[0039] The restricting portion 5 has an open portion 59, which is an opening surrounded by the end of the circumferential restricting portion 53 on the side opposite to the base material 2. The sensing portion 4 is exposed to the outside in the open portion 59. Therefore, the restricting portion 5 does not restrict the expansion of the sensing portion 4 in the direction perpendicular to the support surface 21.

[0040] When the gas detector 1 detects a substance to be measured in a gas, the sensing part 4 expands by adsorbing the substance in the gas. In the second embodiment, as described above, the restricting part 5 restricts the expansion of the sensing part 4 in the direction along the support surface 21, but does not restrict the expansion in the direction perpendicular to the support surface 21. Therefore, compared to the case where the expansion of the sensing part 4 is not restricted by the restricting part 5, the amount of expansion of the sensing part 4 in the direction perpendicular to the support surface 21 is larger, and the increase in the electrical resistance value of the sensing part 4 in this direction is larger. In other words, the increase in the electrical resistance value of the sensing part 4 in the direction where the first terminal portion 312 and the second terminal portion 322 are aligned is larger. For this reason, in the second embodiment, the detection sensitivity is improved compared to the case where the expansion of the sensing part 4 is not restricted by the restricting part 5.

[0041] 2.3. Third Embodiment The gas detector 1 of the third embodiment will be described with reference to Figures 7 to 8. Detailed explanations of the same configuration as in the first embodiment will be omitted as appropriate below.

[0042] In the third embodiment, both the first conductor 31 and the second conductor 32 are arranged on the support surface 21 of the base material 2. The first conductor 31 has a first line portion 311 and a first terminal portion 312 connected to the first line portion 311. The second conductor 32 has a second line portion 321 and a second terminal portion 322 connected to the second line portion 321.

[0043] The first terminal portion 312 is circular in shape when viewed in the thickness direction of the base material 2 (the direction perpendicular to the support surface 21). The first line portion 311 is straight and is connected to the outer circumference of the first terminal portion 312.

[0044] The second terminal portion 322 is annular. The second terminal portion 322 is arranged to surround the first terminal portion 312. A gap is formed in the second terminal portion 322 where the first line portion 311 passes through. The second line portion 321 is straight, connects to the outer circumference of the second terminal portion 322, and extends from the second terminal portion 322 toward the opposite side from the first line portion 311.

[0045] In the third embodiment, the direction in which the first terminal portion 312 and the second terminal portion 322 are aligned is the direction in which the lines extend radially from the first terminal portion 312 toward the second terminal portion 322 surrounding the first terminal portion 312. The direction of the electric field lines between the first terminal portion 312 and the second terminal portion 322 extends radially, as shown by the arrows in Figure 7.

[0046] The sensing part 4 is positioned on the support surface 21 so as to cover the first terminal portion 312 and the second terminal portion 322. When viewed in the thickness direction of the base material 2, the sensing part 4 is circular in shape.

[0047] The restricting section 5 has an upper restricting section 52 that contacts the surface of the sensing section 4 opposite to the base material 2 side. The upper restricting section 52 is circular in shape, matching the shape of the sensing section 4 when viewed in the thickness direction of the base material 2. The restricting section 5 has support legs 55 that connect the upper restricting section 52 and the base material 2. The support legs 55 are fixed to the base material 2 and support the upper restricting section 52. The upper restricting section 52 is fixed to the base material 2 by these support legs 55. The restricting section 5 has two support legs 55, and each support leg 55 connects a part of the outer circumference of the upper restricting section 52 to the base material 2. Note that the number of support legs 55 is not limited to two; any number that is appropriate to support the upper restricting section 52 is acceptable.

[0048] The restricting portion 5 has an open portion 59, which is the gap between the outer circumference of the upper restricting portion 52 and the support surface 21. The sensing portion 4 is exposed to the outside in the open portion 59. Therefore, the restricting portion 5 does not restrict the expansion of the sensing portion 4 in the direction along the support surface 21, except where the support legs 55 are located. In other words, the restricting portion 5 does not restrict the expansion of the sensing portion 4 in the direction in which the first terminal portion 312 and the second terminal portion 322 are aligned, except where the support legs 55 are located.

[0049] When the gas detector 1 detects a substance to be measured in a gas, the sensing part 4 expands by adsorbing the substance in the gas. In the third embodiment, as described above, the restricting part 5 restricts the expansion of the sensing part 4 in the direction perpendicular to the support surface 21, but does not restrict the expansion in the direction along the support surface 21. Therefore, compared to the case where the expansion of the sensing part 4 is not restricted by the restricting part 5, the amount of expansion of the sensing part 4 in the direction along the support surface 21 is larger, and the increase in the electrical resistance value of the sensing part 4 in this direction is larger. In other words, the increase in the electrical resistance value of the sensing part 4 in the direction where the first terminal portion 312 and the second terminal portion 322 are aligned is larger. For this reason, in the third embodiment, the detection sensitivity is improved compared to the case where the expansion of the sensing part 4 is not restricted by the restricting part 5.

[0050] 3. Variant In the first embodiment, the upper restricting portion 52 is in contact with the surface of the sensing portion 4 opposite to the base material 2 side. However, if the expansion of the sensing portion 4 can be sufficiently restricted, there may be portions on the surface of the sensing portion 4 opposite to the base material 2 side that are not in contact with the upper restricting portion 52. It is preferable that more than 50% of the aforementioned surface of the sensing portion 4 is in contact with the lateral restricting portion 51. The aforementioned percentage is more preferably 75% or more, and even more preferably 90% or more. In addition, in the first embodiment, the lateral restricting portion 51 is in contact with the entire end faces on both sides of the outer circumferential surface of the sensing portion 4 in the direction perpendicular to the direction indicated by arrow D1. However, if the expansion of the sensing portion 4 can be sufficiently restricted, there may be portions on the aforementioned end faces of the sensing portion 4 that are not in contact with the lateral restricting portion 51. It is preferable that more than 50% of the aforementioned end faces of the sensing portion 4 is in contact with the lateral restricting portion 51. The aforementioned percentage is more preferably 75% or more, and even more preferably 90% or more. Furthermore, although the opening 59 of the first embodiment opens the entirety of the two end faces in the direction indicated by arrow D1, the restricting portion 5 may have a portion that partially contacts the aforementioned end faces, as long as it does not excessively hinder the expansion of the sensing portion 4 in the direction indicated by arrow D1. Preferably, more than 50% of the aforementioned end faces of the sensing portion 4 are opened by the opening 59. The aforementioned percentage is more preferably 75% or more, and even more preferably 90% or more.

[0051] In the second embodiment, the circumferential restricting portion 53 is in contact with the entire outer surface of the sensing portion 4. However, there may be portions on the outer surface of the sensing portion 4 that are not in contact with the circumferential restricting portion 53, as long as the expansion of the sensing portion 4 in the direction along the support surface 21 is sufficiently restricted. It is preferable that more than 50% of the outer surface of the sensing portion 4 is in contact with the circumferential restricting portion 53. The aforementioned percentage is more preferably 75% or more, and even more preferably 90% or more. In the second embodiment, the opening portion 59 opens the entire surface of the sensing portion 4 opposite to the base material 2. However, the restricting portion 5 may have portions that are in contact with the aforementioned surface, as long as it does not excessively hinder the expansion of the sensing portion 4 in the direction perpendicular to the base material 2. It is preferable that more than 50% of the aforementioned surface of the sensing portion 4 is open by the opening portion 59. The aforementioned percentage is more preferably 75% or more, and even more preferably 90% or more.

[0052] In the third embodiment, the upper restricting portion 52 is in contact with the entire surface of the sensing portion 4 opposite to the base material 2 side. However, if the expansion of the sensing portion 4 in the direction perpendicular to the support surface 21 is sufficiently restricted, there may be portions on the surface of the sensing portion 4 opposite to the base material 2 side that are not in contact with the upper restricting portion 52. It is preferable that more than 50% of the surface of the sensing portion 4 opposite to the base material 2 side is in contact with the upper restricting portion 52. The aforementioned percentage is more preferably 75% or more, and even more preferably 90% or more. In the third embodiment, the opening portion 59 opens the entire outer circumferential surface of the sensing portion 4, except for the portion in contact with the support leg 55. In this way, the restricting portion 5 may have portions that are in contact with the outer circumferential surface of the sensing portion 4, as long as it does not excessively hinder the expansion of the sensing portion 4 in the direction along the support surface 21. It is preferable that more than 50% of the outer circumferential surface of the sensing portion 4 is open by the opening portion 59. The aforementioned percentage is more preferably 75% or more, and even more preferably 90% or more.

[0053] 4. Appearance As shown in the embodiments and modifications described above, this disclosure includes the following aspects:

[0054] A gas detector (1) in the first embodiment comprises a substrate (2) having a support surface (21), a sensing part (4) disposed on the support surface (21) of the substrate (2), a first conductor (31) and a second conductor (32), and a regulating part (5). The first conductor (31) has a first terminal portion (312). The second conductor (32) has a second terminal portion (322) disposed at a distance from the first terminal portion (312). The sensing part (4) has the property of undergoing volume expansion by adsorbing at least one type of substance. Each of the first terminal portion (312) and the second terminal portion (322) is in contact with the sensing part (4). The regulating part (5) is fixed to the substrate (2) and, by contacting the sensing part (4), restricts the expansion of the sensing part (4) in at least one direction other than the direction in which the first terminal portion (312) and the second terminal portion (322) are aligned.

[0055] According to this embodiment, when the sensing part (4) adsorbs a substance, the volume expansion of the sensing part (4) in the direction in which the first terminal part (312) and the second terminal part (322) are aligned increases, which can improve the detection sensitivity of substances using the gas detector (1).

[0056] In the second embodiment, as in the first embodiment, the first terminal portion (312) and the second terminal portion (322) are arranged on the support surface (21) of the base material (2) with a gap between them in one direction along the support surface (21). The sensing portion (4) is arranged on the support surface (21) so as to cover the first terminal portion (312) and the second terminal portion (322).

[0057] In the third embodiment, as in the second embodiment, the first conductor (31) has a plurality of first terminal portions (312). The second conductor (32) has a plurality of second terminal portions (322). The plurality of first terminal portions (312) and the plurality of second terminal portions (322) are arranged alternately with spacing in the aforementioned direction.

[0058] In a fourth embodiment, as in the second or third embodiment, the restricting portion (5) has at least two lateral restricting portions (51). The two lateral restricting portions (51) are arranged in a direction different from the direction in which the first terminal portion (312) and the second terminal portion (322) are aligned along the support surface (21). A sensing portion (4) is arranged between the two lateral restricting portions (51) so as to be in contact with each of the lateral restricting portions (51).

[0059] In the fifth embodiment, in any one of the second to fourth embodiments, the regulating portion (5) has at least an upper regulating portion (52). The upper regulating portion (52) is positioned in contact with the surface of the sensing portion (4) opposite to the substrate (2) side.

[0060] In the sixth embodiment, as in the first embodiment, the first terminal portion (312) is positioned on the support surface (21) of the base material (2). The sensing portion (4) is positioned on the support surface (21) so as to cover the first terminal portion (312). The second terminal portion (322) is positioned on the surface of the sensing portion (4) opposite to the base material (2), at a position facing the first terminal portion (312). The regulating portion (5) is positioned on the support surface (21) of the base material (2) so as to be in contact with the outer circumferential surface of the sensing portion (4).

[0061] In the seventh embodiment, as in the first embodiment, the first terminal portion (312) is positioned on the support surface (21) of the base material (2). The second terminal portion (322) is positioned on the support surface (21) of the base material (2) so as to surround the first terminal portion (312). The sensing portion (4) is positioned on the support surface (21) of the base material (2) so as to cover the first terminal portion (312) and the second terminal portion (322). The regulating portion (5) is positioned in contact with the surface of the sensing portion (4) opposite to the base material (2) side.

[0062] In the eighth aspect, in any one of the first to seventh aspects, the sensing part (4) comprises a matrix having the property of undergoing volume expansion by adsorbing at least one type of substance, and conductive particles dispersed in the matrix. [Explanation of symbols]

[0063] 1. Gas detector 2 Base material 21 Support surface 31 First Conductor 312 1st terminal section 32 Second Conductor 322 2nd terminal section 4. Sensing part 5. Regulatory Department 51 Lateral control section 52 Upper regulatory section

Claims

1. A base material having a support surface, A sensing part disposed on the support surface of the substrate, The first conductor and the second conductor, It includes a regulatory section, The first conductor has a first terminal portion, The second conductor has a second terminal portion that is spaced apart from the first terminal portion. The sensing part has the property of undergoing volume expansion by adsorbing at least one type of substance. Each of the first terminal portion and the second terminal portion is in contact with the sensing portion, The restricting portion is fixed to the substrate and, by contacting the sensing portion, restricts the expansion of the sensing portion in at least one direction other than the direction in which the first terminal portion and the second terminal portion are aligned. Gas detector.

2. The first terminal portion and the second terminal portion are arranged on the support surface of the substrate so as to be spaced apart in one direction along the support surface. The sensing portion is arranged on the support surface so as to cover the first terminal portion and the second terminal portion. The gas detector according to claim 1.

3. The first conductor has a plurality of first terminal portions, The second conductor has a plurality of second terminal portions, The plurality of first terminal portions and the plurality of second terminal portions are arranged alternately with intervals between them in the aforementioned direction. The gas detector according to claim 2.

4. The aforementioned regulating section has at least two lateral regulating sections, The two lateral restricting portions are arranged so as to be aligned in a direction different from the direction in which the first terminal portion and the second terminal portion are aligned along the support surface. The sensing portion is positioned between the two lateral restricting portions so as to be in contact with each of the lateral restricting portions. The gas detector according to claim 2.

5. The aforementioned regulating section has at least an upper regulating section, The upper restricting portion is positioned so as to be in contact with the surface of the sensing portion opposite to the substrate side. The gas detector according to claim 2.

6. The first terminal portion is arranged on the support surface of the substrate, The sensing portion is arranged on the support surface so as to cover the first terminal portion. The second terminal portion is positioned on the surface of the sensing portion opposite to the substrate side, at a position facing the first terminal portion. The regulating portion is positioned on the support surface of the substrate so as to be in contact with the outer circumferential surface of the sensing portion. The gas detector according to claim 1.

7. The first terminal portion is arranged on the support surface of the substrate, The second terminal portion is arranged on the support surface of the substrate so as to surround the first terminal portion. The sensing portion is arranged on the support surface of the substrate so as to cover the first terminal portion and the second terminal portion. The regulating portion is positioned so as to be in contact with the surface of the sensing portion opposite to the substrate side. The gas detector according to claim 1.

8. The sensing part comprises a matrix having the property of undergoing volume expansion by adsorbing at least one type of substance, and conductive particles dispersed in the matrix. The gas detector according to claim 1.

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