Sensor evaluation method and sensor evaluation device

Abstract

To provide a sensor evaluation method and a sensor evaluation device capable of significantly reducing the time required for evaluating a gas sensor.SOLUTION: A sensor evaluation method comprises: a placement step of placing a gas sensor in a chamber; a vacuum step of evacuating the chamber in which the gas sensor is placed; an evaluation gas supply step of supplying, to the evacuated chamber, an evaluation gas to which the gas sensor in the chamber reacts; and an evaluation step of evaluating the gas sensor on the basis of a signal value output from the gas sensor in the chamber.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a sensor evaluation method and a sensor evaluation device. [Background technology]

[0002] Conventionally, in the evaluation of gas sensors such as odor sensors, an evaluation gas that reacts with the gas sensor is injected into a chamber filled with an inert gas such as nitrogen gas, and the gas sensor is evaluated by confirming that the output signal from the gas sensor is at a predetermined value.

[0003] However, this conventional evaluation method has the problem that it takes a long time to evaluate the gas sensor because it is necessary to wait until the inert gas in the chamber is uniformly replaced with the gas for evaluation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4944972 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a sensor evaluation method and a sensor evaluation device that can significantly reduce the time required to evaluate a gas sensor. [Means for solving the problem]

[0006] That is, the sensor evaluation method and the sensor evaluation device according to the present invention are as follows. [1] a placement step of placing a gas sensor in a chamber; a vacuum process of creating a vacuum in a chamber in which the gas sensor is disposed; an evaluation gas supplying step of supplying an evaluation gas to which the gas sensor in the chamber reacts into the evacuated chamber; and evaluating the gas sensor based on a signal value output from the gas sensor in the chamber. [2] The sensor evaluation method according to [1], wherein a plurality of gas sensors are disposed in the chamber. [3] The sensor evaluation method according to [1] or [2], wherein the gas sensor is evaluated based on the difference between the signal value output in the vacuum process and the signal value output in the evaluation gas supply process. [4] A sensor evaluation method according to any one of [1] to [3], wherein a measurement process includes one vacuum process and one evaluation gas supply process, and the change in the signal value over time during this measurement process is measured. [5] The sensor evaluation method according to any one of [1] to [4], further comprising an inert gas filling step of filling the chamber with an inert gas before the evacuation step. [6] The sensor evaluation method according to [5], wherein the gas sensor is evaluated based on the difference between the signal value output in the inert gas filling step and the signal value output in the evaluation gas supply step. [7] The sensor evaluation method according to [4], wherein the measuring step also includes the inert gas filling step. [8] The sensor evaluation method according to [5] or [6], wherein the gas sensor is evaluated based on the difference between the signal value output in the vacuum process and the signal value output in the evaluation gas supply process, and the difference between the signal value output in the inert gas filling process and the signal value output in the evaluation gas supply process. [9] The sensor evaluation method according to any one of [3], [6] and [8], wherein the gas sensor is evaluated based on whether the difference is within a predetermined tolerance range.

[10] The sensor evaluation method according to any one of [1] to [9], wherein a plurality of types of gases are used as the evaluation gas.

[11] The sensor evaluation method according to [5], wherein the inert gas is nitrogen gas.

[12] The sensor evaluation method according to any one of [1] to

[11] , wherein the vacuum is 20 kPa or less.

[13] A chamber for accommodating a gas sensor therein; a gas supply mechanism for supplying an evaluation gas to which the gas sensor in the chamber reacts; a vacuum mechanism for evacuating the chamber; an evaluation unit that evaluates the gas sensor based on a signal value output from the gas sensor in the chamber, The sensor evaluation device, wherein the vacuum mechanism evacuates the chamber before the evaluation gas is supplied into the chamber.

[14] The sensor evaluation device according to

[13] , further comprising a substrate that is disposed within the chamber and on which a plurality of the gas sensors can be mounted.

[15] The sensor evaluation device according to

[13] or

[14] , wherein the gas supply mechanism includes a gas bag or a gas cylinder.

[16] The sensor evaluation device according to any one of

[13] to

[15] , further comprising a safety valve that operates when the pressure in the chamber exceeds a predetermined value. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a sensor evaluation method and a sensor evaluation device that can significantly reduce the time required to evaluate a gas sensor. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an overall schematic diagram of a sensor evaluation device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a schematic diagram showing the structure inside a chamber of the sensor evaluation device according to the embodiment. [Figure 3] 1A and 1B are schematic diagrams showing a method and procedure for evaluating a gas sensor using the sensor evaluation device according to the present embodiment. [Figure 4] 3 is an example of a signal value from a sensor obtained by the sensor evaluation device according to the present embodiment. [Figure 5]FIG. 2 is a schematic diagram showing an example of a sensor to be evaluated by the sensor evaluation device according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention will be described below with reference to the drawings.

[0010] <Configuration of the sensor evaluation device according to this embodiment> As shown in FIG. 1, the sensor evaluation device 100 according to this embodiment includes a chamber 1, a gas supply mechanism 2 that supplies gas into the chamber 1, and an evaluation unit 3 that evaluates a gas sensor S (hereinafter simply referred to as the sensor S) based on a signal value output from the gas sensor S.

[0011] The gas sensor S to be evaluated in this embodiment is not particularly limited as long as it can detect odorants, such as a semiconductor gas sensor, a gas sensor using an organic polymer, or an alcohol detection device. In this embodiment, an example of such a sensor is a gas sensor equipped with an odorant-receiving layer whose electrical conductivity changes when an odorant is adsorbed. Details of this gas sensor will be described later.

[0012] The chamber 1 accommodates one or more gas sensors S therein, and in this embodiment, a sensor evaluation substrate 11 on which a large number of gas sensors S are mounted and arranged in a matrix can be placed inside the chamber 1, as shown in Fig. 2. Specifically, the chamber 1 is a housing having an opening 1a through which the sensor evaluation substrate 11 can be inserted and removed from the chamber 1, a sealing member 12 capable of sealing the opening 1a, an inlet 1b through which gas is introduced into the chamber, and an outlet 1c through which the gas accommodated inside is discharged to the outside. The material and shape of the housing are not particularly limited, as long as they can withstand the pressure of the gas contained in the housing and can block the flow of gas between the inside and the outside by sealing the opening 1a with the sealing member 12 and stopping the flow of gas at the inlet 1b and outlet 1c. As mentioned above, the material of the housing is not particularly limited, but for example, SUS or glass can be suitably used. When a cable is used to output a signal from the gas sensor S to the evaluation unit 3, the cable may be routed to the outside by passing through the sealing member 12, or a pair of ports for connecting the cable may be formed on the inside and outside of the wall surface of the housing. The cable is not particularly limited, and a commercially available cable may be used.

[0013] The gas supply mechanism 2 supplies the evaluation gas to which the gas sensor S to be evaluated reacts into the chamber 1, and includes, for example, an evaluation gas supply flow path 21 connecting the chamber 1 with a plurality of evaluation gas supply sources G1, and a flow rate control mechanism 22 that controls the flow rate of the gas flowing through the evaluation gas supply flow path 21. The flow rate control mechanism 22 includes, for example, a valve 221 provided on the evaluation gas supply flow path 21, and a flow rate control unit 222 that controls the opening and closing of the valve 221. Note that, for example, a gas bag or a gas cylinder can be used as the evaluation gas supply source G1.

[0014] The flow control unit 222 is physically one or more general-purpose computers COM that have analog electrical circuits including buffers, amplifiers, etc., digital electrical circuits including a CPU, memory, DSP, etc., and A / D converters, etc. interposed between them, and this computer COM is configured to perform the function of the flow control unit 222 by the CPU and its peripheral devices working together in accordance with a predetermined program stored in the memory.

[0015] As described above, the evaluation gas is not particularly limited as long as it reacts with the gas sensor S to be evaluated. For example, a gas having one or more functional groups selected from the group consisting of hydroxyl, hydrocarbon, ester, carboxyl, ketone, aldehyde, ether, and amino groups is preferred, and ethanol, heptane, ethyl acetate, and the like are more preferred. It is preferable to use two or more evaluation gases selected from the gases described above. It is even more preferable to use two or more gases with different solubility parameters (SP values) or octanol / water partition coefficients (logPow). The difference between the SP values ​​is preferably 1 to 17. Furthermore, the difference between the logPow values ​​is preferably 0.1 to 5. These evaluation gases may be supplied simultaneously into chamber 1, or may be supplied at different times, for example, during different measurement steps. In this specification, the SP value is expressed as the square root of the ratio of the cohesive energy density to the molar volume, as shown below. SP value = (△E / V)1 / 2 Here, ΔE represents cohesive energy density, and V represents molecular volume, and the values ​​are calculated by Robert F. Fedors et al. and are described, for example, in Polymer Engineering and Science, Vol. 14, pp. 147-154. The octanol / water partition coefficient (logPow) can be determined by the shake-flask method described in JIS Z7260-107 (2000). This coefficient is expressed as the common logarithm of the concentration of each phase when the target substance is in equilibrium in a system in which the octanol phase and the water phase are in contact, and serves as an index of the hydrophobicity of the target substance. A larger coefficient indicates greater hydrophobicity.

[0016] The gas supply mechanism 2 supplies, in addition to the above-mentioned evaluation gas, for example, an inert gas to which the gas sensor S does not react, to the chamber 1, and includes an inert gas supply flow path 23 connecting the chamber 1 with an inert gas supply source G2, and a flow rate control mechanism 24 for controlling the flow rate of the gas flowing through the inert gas supply flow path 23. The flow rate control mechanism 24 includes, for example, a valve 241 provided on the inert gas supply flow path 23, and a flow rate control unit 242 for controlling the opening and closing of the valve 241, and the flow rate control unit 242 may be the same as that described in the section on the evaluation gas.

[0017] As described above, the inert gas is not particularly limited as long as it does not react with the gas sensor S that is the measurement target, and examples thereof include nitrogen gas.

[0018] The evaluation unit 3 receives signal values ​​output from the gas sensor S placed in the chamber 1 and evaluates the performance of the gas sensor S based on these signal values ​​and the state within the chamber 1 at the time each signal value is obtained.

[0019] This evaluation unit 3 is configured to function as the evaluation unit 3, for example, by the aforementioned computer COM, which operates in cooperation with the CPU and its peripheral devices in accordance with a predetermined program stored in the memory. The evaluation unit 3 may be entirely located outside the chamber 1 or partly located inside the chamber 1 .

[0020] The sensor evaluation device 100 according to this embodiment further includes a vacuum mechanism 4 for evacuating the chamber 1 . The vacuum mechanism 4 includes, for example, a vacuum pump 41, an exhaust flow path 42 connecting the outlet 1c of the chamber 1 with the vacuum pump 41, a valve 43 provided on the exhaust flow path 42, and a vacuum control unit 44 that controls the valve. The function of the vacuum control unit 44 is also realized by the aforementioned computer COM operating in cooperation with the CPU and its peripheral devices in accordance with a predetermined program stored in the memory.

[0021] The vacuum pump 41 may be any pump capable of reducing the pressure inside the chamber 1 to a pressure lower than atmospheric pressure, but it is preferable that the vacuum pump 41 be capable of reducing the pressure inside the chamber to 20 kPa or less, and more preferably to 10 kPa or less.

[0022] In addition to the components described above, the sensor evaluation device 100 according to this embodiment may further include a measurement unit M such as a temperature sensor that measures the temperature inside the chamber 1, a humidity sensor, and a pressure sensor that measures the pressure inside the chamber, a safety valve V that operates when the pressure inside the chamber 1 measured by the pressure sensor included in this measurement unit M exceeds a predetermined value, a fan (not shown) that agitates the gas inside the chamber 1, and a display unit (not shown) that displays the evaluation results by the evaluation unit 3. These temperature sensor, humidity sensor, pressure sensor, safety valve, fan, display unit, etc. are not essential components and can be provided as needed.

[0023] <Sensor evaluation method using the sensor evaluation device according to this embodiment> A method for evaluating a sensor S using the sensor evaluation device 100 configured in this manner includes, for example, as shown in Figure 3, an arrangement step S1 of placing the gas sensor S in a chamber 1, an inert gas supply step S2 of supplying an inert gas into the chamber 1, a vacuum step S3 of evacuating the chamber 1 in which the gas sensor S is placed, an evaluation gas supply step S4 of supplying an evaluation gas to which the gas sensor S in the chamber 1 reacts into the evacuated chamber 1, and an evaluation step S5 of evaluating the gas sensor S based on a signal value output from the gas sensor S in the chamber 1.

[0024] The sensor evaluation method according to this embodiment will be described in more detail below. First, a sensor evaluation substrate 11 on which a plurality of gas sensors S are mounted is placed in a chamber 1, and then an opening 1a of the chamber 1 is sealed with a sealing member 12 (placement step S1). Thereafter, while the valve 43 provided on the exhaust flow path 42 remains open, the gas supply mechanism 2 opens only the valve 241 on the inert gas supply flow path 23 to supply the inert gas into the chamber 1, and when the inside of the chamber 1 has been sufficiently replaced with the inert gas and filled with the inert gas, the evaluation unit 3 begins to continuously or intermittently acquire signal values ​​from each sensor S. This process of supplying and filling the inert gas is referred to as the inert gas supply process S2.

[0025] Next, the valves 221, 241 provided on the evaluation gas supply flow path 21 and the inert gas supply flow path 23 are closed, and the vacuum mechanism 4 sucks and exhausts the inert gas from the chamber 1, thereby performing a vacuum step S3 in which the pressure inside the chamber 1 is made lower than atmospheric pressure (vacuum). This vacuum step S3 preferably makes the pressure inside the chamber 1 a vacuum of, for example, 20 kPa or less, more preferably 10 kPa or less.

[0026] After the chamber 1 is evacuated, the gas supply mechanism 2 opens the valve 221 on the evaluation gas supply flow path 21 and supplies the evaluation gas into the chamber 1 in an amount such that the pressure inside the chamber 1 becomes a predetermined pressure, for example, atmospheric pressure.

[0027] When the pressure inside the chamber 1 reaches a predetermined value, the gas supply mechanism 2 closes the valve 221 on the evaluation gas supply flow path 21, and the chamber 1 is maintained filled with the evaluation gas for a predetermined time (evaluation gas supply step S4). The time for maintaining the state in which the evaluation gas is filled can be changed as appropriate depending on the type and concentration of the measurement target, the purpose of measurement, the volume of the chamber used, etc., and may be, for example, from 2 minutes to 5 minutes, or from 3 minutes to 4 minutes.

[0028] The evaluation unit 3 finishes acquiring the signal value from the sensor when a predetermined time has elapsed since the chamber 1 was filled with the evaluation gas. That is, in this embodiment, as shown in Fig. 4, the measurement process is a process between the inert gas supplying process S2, the vacuum process S3, and the evaluation gas supplying process S4, which are each performed once. Note that this measurement process only needs to include at least one vacuum process S3 and one evaluation gas supplying process S4.

[0029] After the measurement step is completed in this manner, the vacuum mechanism 4 opens the valve 43 on the exhaust flow path 42, and the gas supply mechanism 2 opens the valve 241 on the inert gas supply flow path 23 to supply the inert gas into the chamber 1, thereby replacing the evaluation gas in the chamber 1 with the inert gas, thereby starting the next measurement step. From the viewpoint of minimizing the amount of evaluation gas remaining inside the chamber 1, the vacuum step S3 and the inert gas supply step S2 may be repeated multiple times in this order before the next measurement step starts.

[0030] The evaluation unit 3 evaluates each sensor S based on the change over time contained in the time-series data of the output value from each sensor S acquired continuously or intermittently during the measurement process. Specifically, the evaluation unit calculates, from the data for one sensor S, the difference (difference 1) between the signal value from sensor S in the inert gas supply step and the signal value from sensor S in the evaluation gas supply step and / or the difference (difference 2) between the signal value from sensor S in the vacuum step and the signal value from sensor S in the evaluation gas supply step. If the calculated difference is within a predetermined numerical range, the evaluation unit determines that the sensor S satisfies the predetermined performance. Note that the evaluation unit 3 may also acquire output values ​​from a thermometer, hygrometer, pressure gauge, etc., arranged in chamber 1 and appropriately correct the signal value from sensor S based on the information obtained from these.

[0031] The output values ​​from the sensor S in each step used to calculate the difference are preferably acquired at the following times: The output value in the inert gas supply step S2 is preferably acquired after the chamber 1 is filled with the inert gas and after the signal value has stabilized; the output value in the vacuum step S3 is preferably acquired after the chamber 1 has reached a predetermined vacuum state of, for example, 20 kPa or less and after the signal value has stabilized; and the output value in the evaluation gas supply step S4 is preferably acquired after the evaluation gas has been supplied into the chamber 1 and the pressure in the chamber 1 has reached a predetermined value and after the signal value has stabilized.

[0032] If the difference is outside the numerical range, the evaluation unit 3 may further calculate the deviation of the difference from the numerical range, and further evaluate the sensor S based on the value of this deviation.

[0033] <Gas sensor> Here, the gas sensor S evaluated in this embodiment comprises, for example, a sensor substrate 5, an odorant receiving layer 6 formed on the sensor substrate 5, and metal wiring 7 for electrically connecting the odorant receiving layer 6 to, for example, a voltmeter (not shown) that detects the potential change of the odorant receiving layer 6 as a signal value, as shown in Figure 5.

[0034] [substrate] A wide range of materials commonly used in electronic circuits can be used as the sensor substrate 5. Specifically, a substrate made of one or more materials selected from the group consisting of glass epoxy, paper, and glass cloth can be used.

[0035] [Odor receptor layer] The odorant receiving layer 6 preferably contains, for example, a resin composition whose electrical conductivity differs when odorant a is adsorbed and when odorant b, a substance different from odorant a, is adsorbed, and is made of such a resin composition.

[0036] This resin composition contains, for example, a resin (A) and a conductive carbon material (B).

[0037] (Resin (A)) The resin (A) contained in the resin composition according to one embodiment of the present invention is not particularly limited, but preferably contains at least one selected from the group consisting of urethane resins, polyalkylene oxides, acrylic resins, fluorine-containing resins, vinyl polymer resins, silicone resins, polyamide resins, polyester resins, epoxy resins, phenolic resins, phenylene oxides, and polyimides.

[0038] (Conductive carbon material (B)) The conductive carbon material (B) is, for example, a carbon material having a volume resistivity of 0.1 Ω cm or less. This conductive carbon material (B) is dispersed in the resin composition, and the conductive carbon material (B) contacts each other to form conductive paths, thereby imparting conductivity to the resin composition.

[0039] Specific examples of the conductive carbon material (B) include carbon black, carbon nanotubes, and graphene.

[0040] The conductive carbon material (B) is preferably in the form of fibers or spheres.

[0041] When the conductive carbon material (B) is fibrous, the fiber diameter is preferably 0.1 μm to 10 μm, more preferably 0.1 μm to 5 μm, and when the conductive carbon material (B) is fibrous, the fiber length is preferably 0.1 μm to 10 μm, more preferably 1 μm to 10 μm.

[0042] When the conductive carbon material (B) is spherical, the primary particle diameter is preferably 10 nm or more and 200 nm or less, more preferably 20 nm or more and 150 nm or less, and more preferably 100 nm or less, since this can further improve the conductivity and sensor sensitivity in the resin composition.

[0043] The primary particle diameter of the conductive carbon material (B) can be measured, for example, by a transmission electron microscope (TEM). The primary particle diameter of the conductive carbon material (B) can be measured by observing the particle diameter using a microscope and analyzing the image using an image processing device (for example, a digital microscope VHX-700F manufactured by Keyence Corporation). The primary particle diameter of the conductive carbon material (B) can also be determined by other known methods. Furthermore, when the conductive carbon material (B) is a known material or a commercially available product, the primary particle diameter may be a literature value, a catalog value, or the like.

[0044] The content of the conductive carbon material (B) is preferably 5% by weight or more and 60% by weight or less, based on 100% by weight of the total of the resin (A) and the conductive carbon material (B), from the viewpoint of ensuring that the sensor element formed from the resin composition exhibits sufficient conductivity as an odor sensor and sufficient sensitivity as the odor sensor.

[0045] The resin composition may further contain, for example, a surfactant (C) in addition to the resin (A) and conductive carbon material (B) described above, as long as the effects of the present invention are obtained. The surfactant (C) preferably acts as a dispersant for the conductive carbon material (B), and may be, for example, one or more surfactants selected from anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. When a surfactant is added, the weight ratio of the resin (A) to the surfactant (C) [(A) / (C)] is preferably in the range of 1 to 50, in terms of odor discrimination performance. The resin composition may further contain other components in addition to the above-mentioned (A) to (C), and the other components can be suitably used within a range in which both the effects of the present invention and the effects of the other components can be obtained.

[0046] [Metal wiring] The metal wiring 7 is disposed so as to be in contact with the odorant receiving layer 6 described above, and includes, for example, a first metal wiring and a second metal wiring.

[0047] These first and second metal wirings are preferably made of copper, gold, or the like, and preferably have a flat cross-sectional shape.

[0048] The width of each of the first and second metal wirings as viewed perpendicular to the surface of the substrate is preferably 10 μm to 2 mm, more preferably 10 μm to 1 mm, and the height, i.e., thickness, of each of the first and second metal wirings as viewed parallel to the surface of the substrate is preferably 1 μm to 100 μm, more preferably 10 μm to 50 μm.

[0049] It is preferable that the first metal wiring and the second metal wiring are not in direct contact with each other and are arranged substantially parallel to each other.

[0050] As described above, the distance between the first metal wiring and the second metal wiring arranged approximately in parallel is preferably 1 μm or more and 3 mm or less, and more preferably 1 μm or more and 1.5 mm or less.

[0051] It is desirable that the distance between the first metal wiring and the second metal wiring be a predetermined distance (e.g., 500 μm) or less if the electrical conductivity of the odorant receiving layer 315 (i.e., the electrical conductivity of the sensor element 31) is low.

[0052] The length of the first metal wiring and the second metal wiring in contact with the odorant receiving layer is preferably 100 μm or more and 50 mm or less, and more preferably 500 μm or more and 30 mm or less.

[0053] <Effects of this embodiment> According to the sensor evaluation method and sensor evaluation device 100 of this embodiment, the chamber 1 is evacuated before the evaluation gas is supplied into the chamber 1. Therefore, the evaluation gas is supplied into the chamber 1 with force and quickly spreads throughout the chamber 1, making it possible to uniformly distribute the evaluation gas within the chamber 1 in a relatively short time. As a result, the time required for evaluating the gas sensor S can be significantly reduced. For the same reason, even when multiple sensors S are placed within the chamber 1 and evaluated at the same time, the evaluation gas can be supplied as quickly and evenly as possible regardless of the position of each sensor S within the chamber 1. As a result, this effect can be particularly pronounced when multiple sensors S are evaluated within a single chamber 1. This effect will be specifically explained below. For example, let's assume that a sensor evaluation is performed using a 5-L stainless steel container, with the conventional sensor evaluation method, in which the evaluation gas is flowed into the container at 100 mL / min. In this case, it takes 50 minutes just to supply 5 L of evaluation gas to the container. In reality, more than 5 L of evaluation gas is required to uniformly fill the container with the evaluation gas, which requires even longer for sensor evaluation. Even if the flow rate of the evaluation gas is increased to 1 L / min, the supply time alone for the evaluation gas requires more than 5 minutes. Furthermore, if the flow rate of the evaluation gas is increased to 5 L / min, the time required to supply the evaluation gas to the container is shortened to just over 1 minute. However, supplying the evaluation gas into the container at such a high flow rate can cause large fluctuations in the pressure inside the container during sensor evaluation, potentially resulting in fluctuations in the sensor element measurements. On the other hand, when using the same 5 L SUS container and the method according to this embodiment, the test gas can be introduced into the container all at once after the container is evacuated, which significantly shortens the supply time of the test gas. Furthermore, after supplying the test gas, if the valve is kept closed for, for example, about 5 minutes, the sensor can be evaluated after the effects of the pressure have sufficiently subsided. Thus, according to the sensor evaluation method according to this embodiment, by minimizing the time required for supplying the test gas as compared to the conventional method, a sensor can be accurately evaluated in less than 5 minutes when a 5 L container is used.

[0054] The evaluation unit 3 acquires the signal values ​​output from the sensor S over time throughout the entire measurement process and evaluates the performance of the sensor S based on the changes in the signal values ​​over time, so that the sensor performance can be evaluated in more detail than when evaluation is based only on the output values ​​when the evaluation gas is supplied.

[0055] By using two or more types of evaluation gases, the sensor evaluation can be performed with higher accuracy.

[0056] <Other embodiments of the present invention> The present invention is not limited to the above-described embodiment. For example, the evaluation unit is not limited to one that evaluates the sensor using the difference in signal values ​​as described above, but may also evaluate the performance of the sensor by, for example, comparing the waveform of a graph showing the change in signal value from the sensor over time with a known graph waveform. The vacuum mechanism may also evacuate the chamber before the inert gas supply step. The flow rate control mechanism may include a mass flow controller in addition to the valve described above. Furthermore, the gas supply may be controlled only by opening and closing the valve of the gas cylinder that is the gas supply source, without including a flow rate control mechanism. In addition, some or all of the above-described embodiments and modified embodiments may be combined as appropriate, and it goes without saying that various modifications are possible within the scope of the spirit thereof. [Explanation of symbols]

[0057] 100 Sensor evaluation device 1. Chamber 2 Gas supply mechanism 3. Evaluation section 4...Vacuum mechanism V: Safety valve S···Gas Sensor

Claims

1. a step of disposing a gas sensor in the chamber; a vacuum process of creating a vacuum in a chamber in which the gas sensor is disposed; an evaluation gas supplying step of supplying an evaluation gas to which the gas sensor in the chamber reacts into the evacuated chamber; and evaluating the gas sensor based on a signal value output from the gas sensor in the chamber.

2. The sensor evaluation method according to claim 1 , wherein a plurality of sensors are disposed in the chamber.

3. 2. The sensor evaluation method according to claim 1, wherein the gas sensor is evaluated based on a difference between the signal value output in the evacuation step and the signal value output in the evaluation gas supply step.

4. 2. The sensor evaluation method according to claim 1, wherein a measurement step includes one vacuum step and one evaluation gas supply step, and the change in the signal value over time is measured during this measurement step.

5. The sensor evaluation method according to claim 1 , further comprising an inert gas filling step of filling the chamber with an inert gas before the vacuum step.

6. 6. The sensor evaluation method according to claim 5, wherein the gas sensor is evaluated based on a difference between the signal value output in the inert gas filling step and the signal value output in the evaluation gas supplying step.

7. 5. The sensor evaluation method according to claim 4, wherein the measuring step also includes the inert gas filling step.

8. 7. The sensor evaluation method according to claim 6, wherein the gas sensor is evaluated based on a difference between the signal value output in the vacuum step and the signal value output in the evaluation gas supply step, and a difference between the signal value output in the inert gas filling step and the signal value output in the evaluation gas supply step.

9. 9. The sensor evaluation method according to claim 3, wherein the gas sensor is evaluated based on whether the difference is within a predetermined tolerance range.

10. The sensor evaluation method according to claim 1 , wherein a plurality of types of gases are used as the evaluation gas.

11. The sensor evaluation method according to claim 5 , wherein the inert gas is nitrogen gas.

12. The sensor evaluation method according to claim 1 , wherein the vacuum is a vacuum of 20 kPa or less.

13. a chamber for housing the gas sensor therein; a gas supply mechanism for supplying an evaluation gas to which the gas sensor in the chamber reacts; a vacuum mechanism for evacuating the chamber; an evaluation unit that evaluates the gas sensor based on a signal value output from the gas sensor in the chamber, The sensor evaluation device, wherein the vacuum mechanism evacuates the chamber before the evaluation gas is supplied into the chamber.

14. The sensor evaluation device according to claim 13 , further comprising a substrate disposed within the chamber and capable of mounting a plurality of the gas sensors thereon.

15. The sensor evaluation device according to claim 13 , wherein the gas supply mechanism includes a gas bag or a gas cylinder.

16. 14. The sensor evaluation device according to claim 13, further comprising a safety valve that operates when the pressure in the chamber exceeds a predetermined value.

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