Sensor system and gas sensor output correction method

Abstract

This invention provides a sensor system equipped with multiple gas sensors that can mitigate the decrease in gas measurement accuracy due to concentration gradients. [Solution] The sensor system comprises gas sensors 12_1 to 12_4, each positioned at separate locations in a direction parallel to the arrangement plane; flow velocity sensors 14_X1, 14_X2, 14_Y1, and 14_Y2, positioned on the +X, -X, +Y, and -Y directions relative to the gas sensors 12_1 to 12_4; a measuring instrument 2 for measuring the output of each sensor; and a processing device 3 for correcting the output of the gas sensors 12_1 to 12_4 measured by the measuring instrument 2 based on the output of the flow velocity sensors 14_X1, 14_X2, 14_Y1, and 14_Y2 measured by the measuring instrument 2.

Description

[[Technical Field]]

[0001] The present invention relates to a sensor system including a plurality of gas sensors and an output correction method for gas sensors. [[Background Art]]

[0002] Conventionally, odor sensing methods have been known that utilize variations in resonance frequency caused by mass addition when gas is adsorbed to a piezoelectric resonator such as a QCM (Quartz Crystal Microbalance), or changes in resistance value caused by gas reaction on the surface of a heated oxide semiconductor material. Further, by utilizing these principles and arraying a plurality of sensors each formed with a reactive film having different odor selectivity from each other, odor identification is performed through determination using a trained model generated by machine learning such as a neural network from output patterns that differ for each odor, and such methods have been developed. Abnormality determination devices that detect odor components in the environment and monitor the occurrence of abnormalities such as fire, electric leakage, and substance leakage are known.

[0003] For example, Patent Documents 1 to 4 disclose biological gas detection methods and detection devices using gas sensors or odor sensors. In the techniques of Patent Documents 1 to 3, a single gas sensor is used to detect and measure components such as ethyl alcohol, acetone, and hydrogen sulfide contained in exhaled breath. Further, a flow rate sensor measures the volume, flow velocity, and movement direction of exhaled breath, and the measured values are used to calibrate the measurement device or the like, thereby enabling acquisition of correct data. On the other hand, in the technique described in Patent Document 4, a plurality of odor sensors are arranged in an array, and the substance causing the odor is detected by the plurality of odor sensors. [[Prior Art Documents]] [[Patent Documents]]

[0004] [[Patent Document 1]] Japanese Unexamined Patent Publication No. 2023-061605 [[Patent Document 2]] Japanese Unexamined Patent Publication No. 2022-026622 [Patent Document 3] Japanese Patent Publication No. 2020-103437 [Patent Document 4] Japanese Patent Publication No. 2024-122621 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, when multiple sensors are arranged in an array, as in the prior art described in Patent Document 4 above, the positions of each sensor are far apart, so a gas concentration gradient is created between the upstream and downstream of the gas-containing fluid flow due to the influence of wind. The concentration gradient for each sensor differs depending on the wind speed and direction, affecting the sensor output and reducing the accuracy of odor identification. When supplying fluid to the gas sensors, there is a method of using a housing that forms a pump and a fluid flow path to keep the fluid velocity supplied to each sensor constant, but this may result in a gas concentration gradient, leading to insufficient accuracy in odor identification, and there are concerns about the sensor system becoming larger. The present invention has been made in view of the above problems, and aims to provide a sensor system and a gas sensor output correction method that can reduce the decrease in gas measurement accuracy due to concentration gradients in a sensor system equipped with multiple gas sensors. [Means for solving the problem]

[0006] A sensor system according to one aspect of the present invention comprises: a first gas sensor that reacts to a gas in a gaseous state and outputs a value corresponding to the concentration of the gas; a second gas sensor positioned away from the first gas sensor and that reacts to a gas in a gaseous state and outputs a value corresponding to the concentration of the gas; a first fluid sensor positioned on the first gas sensor side relative to the positioning of the first and second gas sensors and that outputs a value relating to the flow rate or flow velocity of the gas; a second fluid sensor positioned on the second gas sensor side relative to the positioning of the first and second gas sensors and that outputs a value relating to the flow rate or flow velocity of the gas; and a correction unit that corrects the output of the first gas sensor and the output of the second gas sensor based on the output of the first fluid sensor and the output of the second fluid sensor.

[0007] In the above configuration, the system may further include a flow direction detection unit for detecting the flow direction of the gas, and the correction unit may correct the output of the first gas sensor and the output of the second gas sensor based on the flow direction detected by the flow direction detection unit and the output of the first fluid sensor and the output of the second fluid sensor.

[0008] In the above configuration, the correction unit may set reference points on the upstream and downstream sides in the flow direction of the gas, calculate the distance of the first gas sensor and the second gas sensor along the flow direction from the upstream or downstream reference point, and correct the output of the first gas sensor and the second gas sensor based on the calculated distance and the output of the first fluid sensor and the output of the second fluid sensor.

[0009] In the above configuration, the substrate may have a front surface and a back surface, the first gas sensor and the second gas sensor may be positioned in the center of the front surface of the substrate, the first fluid sensor may be positioned on the front surface of the substrate on the side of the first gas sensor and further out than the first gas sensor, and the second fluid sensor may be positioned on the front surface of the substrate on the side of the second gas sensor and further out than the second gas sensor.

[0010] In the above configuration, the system may include a substrate having a front surface and a back surface, and a ceiling member having a ceiling surface facing the front surface of the substrate, wherein the first gas sensor and the second gas sensor are arranged on the surface of the substrate, one of the first fluid sensor and the second fluid sensor is positioned on the ceiling surface facing one of the first gas sensor and the second gas sensor, and the other of the first fluid sensor and the second fluid sensor is positioned on the ceiling surface facing the other of the first gas sensor and the second gas sensor.

[0011] Furthermore, an output correction method for a gas sensor according to one aspect of the present invention is an output correction method for a gas sensor of a sensor module comprising: a first gas sensor that reacts to a gas in a gas and outputs a value corresponding to the concentration of the gas; a second gas sensor positioned away from the first gas sensor and that reacts to a gas in a gas and outputs a value corresponding to the concentration of the gas; a first fluid sensor positioned on the first gas sensor side relative to the position of the first and second gas sensors and that outputs a value relating to the flow rate or flow velocity of the gas; and a second fluid sensor positioned on the second gas sensor side relative to the position of the first and second gas sensors and that outputs a value relating to the flow rate or flow velocity of the gas, the method comprising the step of correcting the output of the first gas sensor and the output of the second gas sensor based on the output of the first fluid sensor and the output of the second fluid sensor. [Effects of the Invention]

[0012] According to the present invention, in a sensor system equipped with multiple gas sensors, the decrease in gas measurement accuracy due to concentration gradients can be reduced. [Brief explanation of the drawing]

[0013] [Figure 1] This is a block diagram showing the schematic configuration of the sensor system according to the first embodiment. [Figure 2]It is a schematic diagram showing the configuration of the sensor module according to the first embodiment, wherein (a) is a perspective view, (b) is a plan view, and (c) is a side view. [Figure 3A] It is a plan view of a sensor module showing an example of the sign of a detection value with respect to the direction of wind received by a flow velocity sensor and an example of the wind direction. [Figure 3B] (a) and (b) are graphs showing the flow velocity and gas concentration at each sensor position with respect to the wind direction in FIG. 3A, and (c) is a graph showing the output of each gas sensor with respect to the wind direction in FIG. 3A. [Figure 4A] (a) is a cross-sectional view taken along line A-A of FIG. 3A, and (b) is a graph showing the relationship between the X-direction position of each sensor and the concentration attenuation coefficient with respect to the wind direction shown in (a). [Figure 4B] It is a graph showing the relationship between the flow velocity attenuation coefficient and the concentration attenuation coefficient. [Figure 5A] (a) is a plan view of a sensor module describing an oblique wind direction, and (b) is a plan view of the sensor module describing the position of a virtual sensor with respect to the wind direction of (a). [Figure 5B] (a) and (b) are graphs showing the relationship between the X-direction distance, Y-direction distance of each sensor and the flow velocity with respect to the wind direction in FIG. 5A(a), and (c) is a graph showing the relationship between the combined XY-direction distance obtained by combining (a) and (b) and the flow velocity. [Figure 5C] (a) and (b) are graphs for explaining an outline of a method for acquiring a concentration attenuation coefficient with respect to the wind direction in FIG. 5A(a). [Figure 6] It is a functional block diagram of a processing apparatus according to the first embodiment. [Figure 7A] It is a flowchart showing concentration gradient correction processing. [Figure 7B] It is a flowchart showing sensor position setting processing. [Figure 8A] It is a diagram showing a specific example of a method for calculating each sensor position with respect to wind direction, in which each coordinate point is described. [Figure 8B]It is a table showing the relationship between the azimuth when the flow velocity sensor 14_Y1 is set as north, the sign of the output value of the flow velocity sensor, and the windward and leeward positions of the flow velocity sensor. [Figure 8C] It is a graph showing the relationship between the positions of coordinate points P1 to P3 in FIG. 8A and the concentration attenuation coefficient. [Figure 9] It is a schematic diagram showing the configuration of the sensor module according to the second embodiment, where (a) is a perspective view, (b) is a plan view with the ceiling member removed, and (c) is a side view.

Mode for Carrying Out the Invention

[0014] Hereinafter, with reference to the accompanying drawings, modes for carrying out the present invention will be described in detail. The embodiments described below are examples of implementation means of the present invention, and should be appropriately modified or changed according to the configuration of the apparatus to which the present invention is applied and various conditions, and the present invention is not limited to the following embodiments.

[0015] In addition, in the description of the following drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the vertical and horizontal dimensions and scales of members or parts are different from actual ones. Therefore, specific dimensions and scales should be determined with consideration of the following description. In addition, it goes without saying that the drawings include portions where the relationship and ratio of dimensions differ between drawings. [First Embodiment] [Configuration]

[0016] First, a first embodiment of the present invention will be described. FIGS. 1 to 8B are diagrams showing the first embodiment. The sensor system 100 according to the first embodiment corresponds to an embodiment of the sensor system of the present invention, and as an example, measures the type and concentration of gas. Examples of the gas to be measured include acetone, ethanol, ammonia, CO, H2 and the like. The gas to be measured in the present embodiment is not specified. FIG. 1 is a block diagram showing a schematic configuration of the sensor system 100 according to the first embodiment. As shown in Figure 1, the sensor system 100 according to the first embodiment comprises a sensor module 1, a measuring instrument 2, a processing unit 3, and an output device 4.

[0017] Sensor module 1 comprises gas sensors 12_1, 12_2, 12_3, and 12_4, and flow velocity sensors 14_X1, 14_X2, 14_Y1, and 14_Y2. Hereinafter, gas sensors 12_1, 12_2, 12_3, and 12_4 will be simply referred to as "gas sensor 12" when there is no need to distinguish between them. Similarly, flow velocity sensors 14_X1, 14_X2, 14_Y1, and 14_Y2 will be simply referred to as "flow velocity sensor 14" when there is no need to distinguish between them.

[0018] The gas sensor 12 can employ, for example, oscillator type, semiconductor type, electrochemical type, or NDIR type gas sensors. An oscillator type gas sensor detects, for example, fluctuations in the resonant frequency due to the addition of gas mass to a piezoelectric resonator. A semiconductor type gas sensor detects, for example, changes in resistance due to gas reactions on the surface of a heated oxide semiconductor material. An electrochemical type gas sensor detects gas concentration using, for example, oxidation-reduction reactions. An NDIR type gas sensor utilizes the property that gas molecules absorb infrared light of a specific wavelength, and detects gas concentration from the difference in the amount of infrared light that reaches the infrared sensor.

[0019] Furthermore, the gas sensors 12_1 to 12_4 may all be composed of sensors that detect the concentration of the same type of gas, or they may each be given different gas selectivity. The gas sensors 12_1 to 12_4 may have reactivity to multiple gas molecules contained in a gas. This gas containing multiple gas molecules is sometimes called an odor. Also, in the first embodiment, the gas sensor 12 is, for example, a semiconductor type gas sensor.

[0020] The flow velocity sensor 14 is a sensor that detects the flow velocity and direction of a gas. That is, it can detect the flow velocity and direction of a gas containing the gas being measured. The flow velocity sensor 14 is a thermal sensor manufactured, for example, using MEMS (Micro Electro Mechanical Systems). Hereinafter, the direction of gas flow may be referred to as "wind direction."

[0021] The measuring instrument 2 measures the output value of each sensor in the sensor module 1 and outputs the measured output values ​​to the processing unit 3. The output value of the gas sensor 12 is, for example, the frequency change amount ΔF calculated from the oscillation frequency F0 before gas adsorption and the oscillation frequency Fs after gas adsorption, if the gas sensor 12 is composed of a piezoelectric resonator. In the case of a semiconductor gas sensor, it is, for example, the resistance change rate R0 / Rs calculated from the resistance value R0 before gas adsorption and the resistance value Rs after gas adsorption. These values ​​are correlated with the gas concentration and can therefore also be called "gas concentration".

[0022] The measuring instrument 2 measures the output value corresponding to the gas concentration of each gas sensor 12 as described above. On the other hand, the output value of the flow velocity sensor 14 is a flow velocity value with a sign of + or - corresponding to the flow velocity and wind direction, and the measuring instrument 2 measures this flow velocity value with this sign. The measuring instrument 2 may also be equipped with an A / D converter, and may be configured to output the digital value obtained by A / D conversion of each measured output value to the processing unit 3.

[0023] The processing unit 3 performs two processes: correcting the output value of the gas sensor 12 based on the flow velocity value, which is the output value of the flow velocity sensor 14 measured by the measuring instrument 2; and determining the odor based on the corrected output value. If no concentration gradient occurs and correction of the output value of the gas sensor 12 is not necessary, the odor determination process is performed based on the uncorrected output value. In addition to determining the type of odor, the odor intensity may also be determined in the odor determination process. In this case, the odor intensity is an index that indicates whether the odor is stronger or weaker, even if it is the same type of odor. Furthermore, if the type of odor is dangerous to the human body or has the potential to cause accidents such as fires, the system may be configured to perform an abnormality determination.

[0024] Here, when the gas containing the gas to be measured is carried by the wind, a concentration gradient of the gas concentration is generated on the surface of the substrate 10 depending on the strength and direction of the wind. When a concentration gradient is generated, a concentration difference is created between the gas sensors 12 depending on their position. In this invention, the difference in output values ​​due to this concentration difference is corrected. Hereinafter, the output value of the gas sensor 12 may be referred to as "gas concentration". Output device 4 is a device that outputs the judgment result of the odor judgment process in processing device 3. Output methods include, for example, display output, print output, and signal output to other devices via a network.

[0025] Next, the specific configuration of the sensor module 1 will be described based on Figures 2(a), (b), and (c). Figures 2(a) to (c) are schematic diagrams showing the configuration of the sensor module 1 according to the first embodiment, where Figure 2(a) is a perspective view, Figure 2(b) is a plan view, and Figure 2(c) is a side view seen from the -Y direction. In Figure 2, the height direction of the sensor module 1 is the Z direction, the length direction of the sensor module 1 is the X direction, and the direction perpendicular to the Z direction and the X direction is the Y direction. As shown in Figures 2(a) to (c), the sensor module 1 has a substrate 10 with a front surface and a back surface, and the gas sensor 12 and the flow velocity sensor 14 are arranged on the front surface of the substrate 10.

[0026] To explain the specific positional relationship, gas sensors 12_1 to 12_4 are arranged in a 2x2 array in the center of the substrate 10 surface in the X and Y directions. More specifically, with respect to the center of the substrate 10 surface, gas sensor 12_1 is positioned on the -X and +Y side, and gas sensor 12_2 is positioned on the +X and +Y side. In addition, with respect to the center of the substrate 10 surface, gas sensor 12_3 is positioned on the -X and -Y side, and gas sensor 12_4 is positioned on the +X and -Y side. In the example shown in Figures 2(a) to (c), each gas sensor 12 is positioned at a predetermined interval in the X and Y directions.

[0027] On the other hand, the flow velocity sensors 14 are positioned such that flow velocity sensor 14_X1 is located at the center of the Y direction at the +X side edge of the substrate 10 surface, and flow velocity sensor 14_X2 is located at the center of the Y direction at the -X side edge of the substrate 10 surface. In addition, flow velocity sensor 14_Y1 is located at the center of the X direction at the +Y side edge of the substrate 10 surface, and flow velocity sensor 14_Y2 is located at the center of the X direction at the -Y side edge of the substrate 10 surface. In other words, on the surface of the substrate 10, each flow velocity sensor 14 is positioned further out than each gas sensor 12. [Regarding the effect of concentration gradients on output values] Next, the effect of the concentration gradient on the output value of the gas sensor 12 will be explained based on Figures 3A, 3B(a), (b), and (c).

[0028] Figure 3A is a plan view of the sensor module 1 showing an example of the sign of the flow velocity value of the flow velocity sensor 14 with respect to the direction of wind, and the wind direction. Figures 3B(a) and 3B(b) are graphs showing the flow velocity value and normalized gas concentration at each sensor position with respect to the wind direction WD in Figure 3A, and Figure 3(c) is a graph showing an example of the output value of each gas sensor 12 with respect to the wind direction WD in Figure 3A. In Figure 3B(a), the horizontal axis is the distance in the X direction and the vertical axis is the flow velocity; in Figure 3B(b), the horizontal axis is the distance in the X direction and the vertical axis is the normalized gas concentration; and in Figure 3B(c), the numbers on the horizontal axis correspond to the last digit of the gas sensor's sign and the vertical axis is the resistance change rate R0 / Rs.

[0029] In the first embodiment, each flow velocity sensor 14 outputs a positive value for gas flow from the outside to the inside of the sensor module 1, and a negative value for gas flow from the inside to the outside of the sensor module 1, as shown by the + and - signs in Figure 3A, for example. For example, as shown by the wind direction WD in Figure 3A, if gas flows in on the wind from the +X direction on the outside of the sensor module 1 to the -X direction, the flow velocity sensor 14_X1 outputs a positive value and the flow velocity sensor 14_X2 outputs a negative value.

[0030] Figures 3B(a) and (b) are graphs showing the flow velocity and normalized gas concentration as a function of distance in the X-axis direction, with the position of the flow velocity sensor 14_X2 set as 0. As shown in Figure 3B(a), with respect to the wind direction WD in Figure 3A, the flow velocity increases as the distance from the flow velocity sensor 14_X2 toward the windward direction increases. That is, the flow velocity is slowest at the position of the flow velocity sensor 14_X2, and gradually increases in the order of gas sensors 12_1 and 12_3, gas sensors 12_2 and 12_4, and flow velocity sensor 14_X1. Specifically, the gas carried by the wind diffuses across the surface of the substrate 10 from windward to leeward. This causes a decrease in concentration due to diffusion on the surface of the substrate 10. The decrease in concentration due to the concentration gradient caused by this diffusion becomes larger as you move toward the leeward direction, so the amount of decrease in gas concentration due to the concentration gradient differs depending on the position of the gas sensors 12 arranged in the array. That is, the output value of the gas sensors 12 decreases with the concentration gradient, and the amount of decrease increases as you move toward the leeward direction.

[0031] When a gas concentration gradient occurs, as shown in Figure 3B(b), with respect to the wind direction WD in Figure 3A, the gas concentration increases as the distance from the reference position toward the windward direction increases. That is, the concentration is lowest at the position of velocity sensor 14_X2, and gradually increases in the order of gas sensors 12_1 and 12_3, gas sensors 12_2 and 12_4, and velocity sensor 14_X1. Note that in the graph shown in Figure 3B(b), the gas concentration is normalized so that the gas concentration at the position of velocity sensor 14_X1 is 1. That is, if the gas concentration at the position of velocity sensor 14_X1 is G0, the gas concentrations at the positions of gas sensors 12_1 to 12_4 are G1, G2, G3, and G4 respectively, and the gas concentration at the position of velocity sensor 14_X2 is G5, then the normalized gas concentrations at each position are G1 / G0, G2 / G0, G3 / G0, G4 / G0, and G5 / G0. Hereafter, the normalized gas concentration will be referred to as the concentration decay coefficient.

[0032] In the example shown in Figures 3B(a) to (c), gas sensors 12_1 to 12_4 are all the same sensor. With respect to the reference position, gas sensors 12_1 and 12_3 are at the same distance in the X-axis direction, and gas sensors 12_2 and 12_4 are at the same distance in the X-axis direction. Therefore, as shown in Figure 3B(c), the resistance change rates of gas sensors 12_1 and 12_3 are the same, and the resistance change rates of gas sensors 12_2 and 12_4 are the same. In other words, it can be seen that the output value differs depending on the position, even for gases containing the same gas, due to the occurrence of a concentration gradient.

[0033] Furthermore, it can be seen that the flow velocity and gas concentration change linearly with respect to the distance in the X-axis direction, and that the flow velocity and gas concentration decrease linearly as the distance from the reference position increases. In other words, the relationship between the flow velocity and gas concentration at each sensor position is approximately the same, so if the relationship between the wind direction and flow velocity measured by the flow velocity sensor 14 and the distance of each gas sensor 12 from the reference position is known, it is possible to deduce how much the output of the gas sensor 12 is attenuated with position due to the gas concentration gradient. Specifically, it is possible to deduce the concentration attenuation coefficient corresponding to the position of each gas sensor 12. Once the concentration attenuation coefficient is known, the sensor output correction value, which is the correction value of the output value of each gas sensor 12, can be calculated according to the following equation (1). Sensor output correction value = Sensor output value / Concentration attenuation coefficient ... (1) In equation (1) above, the sensor output value is, for example, the resistance change rate R0 / Rs in the case of a semiconductor gas sensor. In this case, the sensor output value that has decreased due to the concentration gradient can be corrected by dividing the resistance change rate R0 / Rs by the concentration decay coefficient. [Method for obtaining the concentration decay coefficient]

[0034] Next, based on Figures 4A(a), 4A(b), and 4B, a method for obtaining the concentration attenuation coefficient, limited to the X-axis direction, will be explained as an example. Figure 4A(a) is a cross-sectional view along line AA in Figure 3A, and Figure 4A(b) is a graph showing the relationship between the concentration attenuation coefficient and the position of each sensor in the X-direction with respect to the wind direction WD shown in Figure 4A(a). Figure 4B is a graph showing the relationship between the flow velocity attenuation coefficient and the concentration attenuation coefficient.

[0035] In Figure 4A(b), the horizontal axis represents distance in the X direction, and the vertical axis represents the concentration decay coefficient. In Figure 4A(b), position X1 represents the position of flow velocity sensor 14_X1, and position X2 represents the position of flow velocity sensor 14_X2. Furthermore, 12_1 and 12_2 in Figure 4A(b) represent the positions in the X direction of gas sensors 12_1 and 12_2, respectively. The distance in the X direction is the distance from position X1 to each sensor, with position X1 as the reference position. In Figure 4B, the horizontal axis represents the concentration decay coefficient, and the vertical axis represents the flow velocity decay coefficient. Note that in the graph shown in Figure 4B, the flow velocity values ​​are normalized so that the flow velocity value at the position of flow velocity sensor 14_X1 is 1. In other words, if the flow velocity at the position of flow velocity sensor 14_X1 is Vx1, the flow velocities at the positions of gas sensors 12_1 to 12_4 are V1, V2, V3, and V4 respectively, and the flow velocity at the position of flow velocity sensor 14_X2 is Vx2, then the normalized flow velocities at each position are V1 / Vx1, V2 / Vx1, V3 / Vx1, V4 / Vx1, and Vx2 / Vx1. Hereafter, the value normalized by the flow velocity value Vx1 will be called the flow velocity attenuation coefficient. Also, in Figure 4B, the X1 flow velocity represents the flow velocity attenuation coefficient at the position of flow velocity sensor 14_X1, and the X2 flow velocity represents the flow velocity attenuation coefficient at the position of flow velocity sensor 14_X2.

[0036] To obtain the concentration decay coefficient, for example, a gas such as ethanol with an arbitrarily set concentration is used, and the gas is carried by a wind blowing from the +X direction to the -X direction, as shown in the wind direction WD in Figure 4A(a), and the sensor output values ​​of the flow velocity sensors 14_X1 and 14_X2 at this time are obtained. Here, the XY coordinates on the surface of the substrate 10 for the flow velocity sensors 14_X1, 14_X2, 14_Y1, and 14_Y2, and the XY coordinates on the surface of the substrate 10 for the gas sensors 12_1 to 12_4 are known and are pre-stored in a memory (not shown) of the processing unit 3.

[0037] When a gas containing gas is carried by the wind, both its velocity and concentration are attenuated by diffusion, so the attenuation of velocity and concentration occur in a similar manner. As shown in Figure 4A(b), the concentration attenuation coefficient decreases linearly as you move from position X1 to position X2. That is, it attenuates linearly with respect to the distance in the X direction from position X1. This relationship between the concentration attenuation coefficient and distance can be obtained as a linear function shown in equation (2) below. y = ax + b (2) In equation (2) above, y is the concentration decay coefficient, x is the distance, a is the slope, and b is the intercept.

[0038] Furthermore, as shown in Figure 4B, since the velocity attenuation coefficient and the concentration attenuation coefficient are correlated, the slope a and intercept b of the linear function shown in equation (2) above can be determined from the velocity attenuation coefficient. Specifically, the slope a is determined from equation (3) below, and the intercept b is set to 1. In equation (3) below, RVx2 is the velocity attenuation coefficient of the velocity value Vx2 at velocity sensor 14_X2 when the velocity value Vx1 at velocity sensor 14_X1 is set to 1, and can be calculated from equation (4) below. Also, in equation (3) below, T is the distance between the X coordinates of velocity sensor 14_X1 and velocity sensor 14_X2. The concentration attenuation coefficient y is determined from equation (2) above and corrected using equation (1) above. a = (RV x 2 - 1) / T (3) RVx2 = Vx2 / Vx1 (4)

[0039] The concentration decay coefficient can be obtained in the same way when a gas containing gas flows on wind blowing from the -X direction to the +X direction. This can also be obtained when the gas flows on wind in other directions, such as the Y axis. Furthermore, this method is applicable even if gas sensors 12_1 to 12_4 are composed of different materials, as the gas concentration decay rate is the same. [Correction method when extending to the X and Y axes] Next, we will explain the correction method when extended to the X and Y axes, based on Figures 5A(a) and (b), Figures 5B(a), (b) and (c), and Figures 5C(a) and (b).

[0040] Figure 5A(a) is a plan view of sensor module 1 showing the diagonal wind direction WD, and Figure 5A(b) is a plan view of sensor module 1 showing the position of a virtual sensor relative to the wind direction WD in Figure 5A(a). Figures 5B(a) and (b) are graphs showing the relationship between the distance in the X and Y directions of each sensor and the flow velocity relative to the wind direction WD in Figure 5A(a), and Figure 5B(c) is a graph showing the relationship between the distance in the X and Y directions of each sensor and the flow velocity. Figures 5C(a) and (b) are graphs illustrating the outline of the method for obtaining the concentration attenuation coefficient relative to the wind direction WD in Figure 5A(a).

[0041] In Figure 5B(a), the horizontal axis represents distance in the X-axis direction, and the vertical axis represents flow velocity. In Figure 5B(b), the horizontal axis represents distance in the Y-axis direction, and the vertical axis represents flow velocity. In Figure 5B(c), the horizontal axis represents distance in the XY direction, and the vertical axis represents flow velocity. In Figure 5C(a), the horizontal axis represents distance in the XY direction, and the vertical axis represents flow velocity. In Figure 5C(b), the horizontal axis represents distance in the XY direction, and the vertical axis represents the concentration decay coefficient. The XY direction also represents the diagonal direction that intersects both the X and Y axes.

[0042] As shown in the wind direction WD in Figure 5A(a), when a gas containing gas flows in with an oblique wind, the internal division point between the flow velocity sensors 14 is calculated from the ratio of the flow velocity values ​​detected by each flow velocity sensor 14, and two points are set, one upwind and one downwind. Specifically, the coordinates of an unknown virtual sensor are set based on the known coordinate information of the upwind flow velocity sensors 14_X2 and 14_Y1 and the downwind flow velocity sensors 14_X1 and 14_Y2, and the flow velocity values ​​detected by each flow velocity sensor 14. That is, as shown in Figure 5A(b), the coordinates of two points corresponding to the upwind virtual sensor 14_X2Y1 and the downwind virtual sensor 14_X1Y2 are set.

[0043] Furthermore, a straight line is drawn connecting the two set points, and the intersection point where the coordinates of each gas sensor 12 intersect this line XY perpendicularly is set as the position of each gas sensor 12 relative to the wind direction. In the example shown in Figure 5A(b), gas sensors 12_1 and 12_4 have coordinates on the line XY, so those coordinates are used as is, and for gas sensors 12_2 and 12_3, the coordinates of the intersection point where they intersect the line XY perpendicularly are determined from their respective coordinates. Then, the distance between the virtual sensor 14_X2Y1 and each gas sensor 12 on the line XY is determined as the distance in the XY direction. Furthermore, the flow velocity in the XY direction at each virtual sensor 14_X2Y1 and 14_X1Y2 is determined.

[0044] Conceptually, the flow velocity in the X and Y directions is obtained by combining the flow velocity for the distance in the X direction shown in Figure 5B(a) and the flow velocity for the distance in the Y direction shown in Figure 5B(b) using a vector synthesis method. This allows us to determine the flow velocity in the X and Y directions for the distance in the X and Y directions of each sensor, as shown in Figure 5B(c). In Figure 5B(a), X1 and X2 represent flow velocity sensors 14_X1 and 14_X2, and in Figure 5B(b), Y1 and Y2 represent flow velocity sensors 14_Y1 and 14_Y2. In Figure 5B(c), X2Y1 and X1Y2 represent virtual sensors 14_X2Y1 and 14_X1Y2.

[0045] As shown in Figures 5B(c) and 5C(a), if the positions of the virtual sensors 14_X2Y1 and 14_X1Y2 and the relationship between the XY position of each gas sensor 12 and the flow velocity are known, the slope a and intercept b of equation (2) above can be determined. This allows us to determine the relationship between the positions of the virtual sensors 14_X2Y1 and 14_X1Y2 and the XY position of each gas sensor 12 and the concentration decay coefficient, as shown in Figure 5C(b). The above describes the relationship between each sensor position and the concentration decay coefficient for gas flows in one direction, as shown in Figures 5A(a) and (b). [Functional configuration of the processing unit 3] Next, the functional configuration of the processing unit 3 will be described based on Figure 6. Figure 6 is a block diagram showing the functional configuration of the processing unit 3 according to the first embodiment. As shown in Figure 6, the processing device 3 is configured to include a correction unit 30 and an odor determination unit 31. The correction unit 30 includes a wind direction determination unit 301, a sensor position setting unit 302, a concentration attenuation coefficient calculation unit 303, and an output value correction unit 304.

[0046] One or more functions of the functional components of the processing unit 3 may be implemented by an integrated circuit, such as a microcomputer. The microcomputer is composed of a CPU (Central Processing Unit) that controls calculations and the entire device based on a control program, a ROM (Read Only Memory) that stores the CPU's control program and the like in advance in a predetermined area, a RAM (Random Access Memory) for storing data read from the ROM and the calculation results necessary for the CPU's calculation process, and an I / F (Interface) that mediates data input and output to and from external devices. These components are connected to each other and enable data exchange via a bus, which is a signal line for transferring data. In other words, one or more of the above functions may be realized by executing a control program using the CPU of a microcomputer. The wind direction determination unit 301 determines the wind direction of the gas containing the gas to be measured that has flowed towards the sensor module 1 based on the flow velocity value and its sign output from each flow velocity sensor 14.

[0047] The sensor position setting unit 302 sets the position of each sensor relative to the wind direction based on the wind direction determined by the wind direction determination unit 301, the flow velocity detected by each flow velocity sensor 14, and the coordinate information pre-set for each sensor. For winds in an oblique direction, the position of a virtual sensor is also set as the position of each sensor.

[0048] The concentration attenuation coefficient calculation unit 303 calculates the flow velocity in the wind direction at the flow velocity sensor or virtual sensor corresponding to the wind direction, based on the flow velocity values ​​of each flow velocity sensor 14. For the flow velocity in the wind direction along the X-axis or Y-axis, the flow velocity values ​​of flow velocity sensors 14_X1 and 14_X2 or flow velocity sensors 14_Y1 and 14_Y2 are used as is. Furthermore, the concentration attenuation coefficient calculation unit 303 calculates the flow velocity attenuation coefficient from equation (4) above using the flow velocity value of the downstream flow velocity sensor or virtual sensor corresponding to the wind direction.

[0049] The concentration attenuation coefficient calculation unit 303 further determines the distance T between two flow velocity sensors or two virtual sensors corresponding to the wind direction from their coordinate information, and uses the distance T and the flow velocity attenuation coefficient of the downwind flow velocity sensor or virtual sensor to determine the slope a of equation (2) from equation (3) above. Since the intercept b is 1, a linear equation for the concentration attenuation coefficient is obtained.

[0050] The concentration decay coefficient calculation unit 303 further calculates the distance of each gas sensor 12 from the coordinates of a reference flow velocity sensor or virtual sensor based on the position of each gas sensor 12 set by the sensor position setting unit 302. Furthermore, using the calculated distance, it calculates the concentration decay coefficient corresponding to each gas sensor 12 from equation (2) obtained by substituting the slope a obtained from equation (3) above.

[0051] The output value correction unit 304 corrects the output values ​​of gas sensors 12_1 to 12_4 using the concentration decay coefficients corresponding to each gas sensor 12_1 to 12_4 calculated by the concentration decay coefficient calculation unit 303, from equation (1) above. The corrected sensor output values ​​are then output to the odor determination unit 31. If correction is not necessary, the uncorrected sensor output values ​​are output to the odor determination unit 31.

[0052] The odor determination unit 31 uses machine learning, such as a neural network, to determine the type of odor based on the corrected or uncorrected output values ​​of the gas sensors 12_1 to 12_4 from the output value correction unit 304. The type of odor is typically a type of odor that a person can perceive with their sense of smell. Examples include the smell of burnt food and the smell of food. To determine the type of odor, for example, a trained model is used that has been trained on the relationship between the output value of the gas sensor 12 and the type of odor. During training, for example, when the gas sensor 12 is measuring a certain type of odor, a person can smell that odor and input the type of odor via a touch panel or the like, thereby learning the type of odor. The odor determination unit 31 outputs the odor determination result to the output device 4. [Odor detection process] Next, the odor determination process performed by the processing device 3 will be described based on Figure 7A. Figure 7A is a flowchart of the odor determination process according to the first embodiment. When the odor detection process is executed in the processing device 3, the process first proceeds to step S100, as shown in Figure 7A. In step S100, the sensor system 100 starts measuring the flow velocity and wind direction using the flow velocity sensor 14 of the sensor module 1, and the gas concentration using the gas sensor 12, and then proceeds to step S102. In step S102, it is determined whether or not there is a reaction in any of the flow velocity sensors 14. If it is determined that there is a reaction (YES), the process proceeds to step S104. If it is determined that there is no reaction (NO), the series of processes ends. If the process proceeds to step S104, it is determined whether or not there was a reaction in the output value of the gas sensor 12. If it is determined that there was a reaction (YES), the process proceeds to step S106. If it is determined that there was no reaction (NO), the series of processes ends. If the process proceeds to step S106, the output of the flow velocity sensor 14 with the largest flow velocity value is selected, and the process proceeds to step S108.

[0053] In step S108, it is determined whether the output values ​​of the other flow velocity sensors 14 located coaxially with the flow velocity sensor 14 with the highest flow velocity value are non-zero. If it is determined that the output value is non-zero (YES), the process proceeds to step S110; otherwise, the process ends. For example, if the flow velocity is slow and the gas containing gas only reaches one of the two coaxially located flow velocity sensors 14, or if for some reason the gas is only detected by one of them, the process ends. Note that the determination of an output value of 0 does not have to be limited to 0; values ​​below a predetermined threshold may also be considered as 0.

[0054] If the process proceeds to step S110, it is determined whether the output values ​​of at least one pair of flow velocity sensors 14 located in the same direction (X-axis and Y-axis) are different. If it is determined that they are different (YES), the process proceeds to step S112; otherwise, it proceeds to step S120. If the output values ​​of the two flow velocity sensors 14 located in the same direction are the same, no concentration gradient is generated, and therefore no correction is necessary. For this reason, the process proceeds to step S120 without performing any correction. If the process proceeds to step S112, the sensor position setting process is executed to determine the wind direction and set the position of each sensor, and then the process proceeds to step S114.

[0055] In step S114, it is determined whether the direction from which the wind is blowing is from a direction other than the Z-axis direction. If it is determined that the wind is blowing from a direction other than the Z-axis direction (YES), the process proceeds to step S116; otherwise, it proceeds to step S120. Here, if the gas containing the gas is flowing on the wind from the Z-axis direction, no concentration gradient is generated, so no correction is necessary. Therefore, the process proceeds to step S120 without performing any correction. If the process proceeds to step S116, the slope of equation (2) above, which is the equation for the concentration attenuation coefficient on the sensor, is calculated from the flow velocity attenuation coefficient based on the output value of each flow velocity sensor 14 corresponding to the wind direction, and the process proceeds to step S118.

[0056] In step S118, the distance of each gas sensor 12 in the wind direction is calculated, and the concentration attenuation coefficient of each gas sensor 12 is calculated from equation (2) using the calculated distances. Then, the sensor output correction value of each gas sensor 12 is calculated from equation (1) using the calculated concentration attenuation coefficient and the sensor output value. After that, the process proceeds to step S120. In step S120, odor detection processing is performed using a trained model based on either the corrected sensor output value obtained by adjusting the output value of each gas sensor 12, or the uncorrected sensor output value, and the result of this detection is output to the output device 4. After that, the series of processes is terminated. [Sensor position setting process] Next, the sensor position setting process performed in step S112 will be explained based on Figures 7B to 8C. Figure 7B is a flowchart of the sensor position setting process. In step S112, once the sensor position setting process is executed, the process first proceeds to step S200, as shown in Figure 7B. In step S200, it is determined whether the output values ​​of each flow velocity sensor 14 are all negative. If it is determined that they are all negative (YES), the process proceeds to step S202. If it is determined that they are not negative (NO), the process proceeds to step S204. If the process proceeds to step S202, it is determined that the wind is coming from the Z-axis direction, and the series of processes is terminated, returning to the original process.

[0057] On the other hand, if the process proceeds to step S204, it is determined whether the flow velocity value of one of the two coaxial flow velocity sensors 14 is 0 or not. If it is determined that both are 0 (YES), the process proceeds to step S206; otherwise, it proceeds to step S208.

[0058] If the process proceeds to step S206, if the velocity values ​​of both flow velocity sensors 14_Y1 and 14_Y2 on the Y axis are 0, the system is set to wind in the X axis direction. If the velocity values ​​of both flow velocity sensors 14_X1 and 14_X2 on the X axis are 0, the system is set to wind in the Y axis direction. After that, the series of processes is terminated and the system returns to the original process. For example, if the wind is coming from the +X direction, the velocity values ​​of both flow velocity sensors 14_Y1 and 14_Y2 on the Y axis will be 0. On the other hand, if the process proceeds to step S208, the system selects the windward direction for the positive sign of the flow velocity value of the flow velocity sensor 14 and the leeward direction for the negative sign, and then proceeds to step S210.

[0059] Here, Figure 8A is a diagram showing a specific example of how to calculate the position of each sensor relative to the wind direction, with each coordinate point indicated on sensor module 1. Figure 8B is a table showing the relationship between the direction (with +Y direction as north), the sign of the output value of the flow velocity sensor, and the upwind and downwind positions of the flow velocity sensor.

[0060] In the example shown in Figure 8A, as indicated by the straight arrows in the figure, a gas containing gas is flowing in on a wind from the northwest (NW), and positive velocity values ​​are obtained from velocity sensors 14_X2 and 14_Y1. In addition, negative velocity values ​​are obtained from velocity sensors 14_X1 and 14_Y2. This allows us to select the upwind position for velocity sensors 14_X2 and 14_Y1, and the downwind position for velocity sensors 14_X1 and 14_Y2. Hereafter, the positions of velocity sensors 14_X1, 14_X2, 14_Y1, and 14_Y2 may simply be referred to as X1, X2, Y1, and Y2.

[0061] In other words, as shown in Figure 8B, when the wind direction is northeast NE, the signs of the output values ​​of the X1, X2, Y1, and Y2 flow velocity sensors are +, -, +, -; when the wind direction is southeast SE, they are +, -, -, +; and when the wind direction is southwest SW, they are -, +, +, -. Also, when the wind direction is along the Z axis, the signs of the output values ​​of the X1, X2, Y1, and Y2 flow velocity sensors are -, -, -, -. In step S210, based on the flow velocity values ​​of each flow velocity sensor 14, the internal division point between the upwind and downwind flow velocity sensors 14 is calculated, and two points are set. Then, the process proceeds to step S212. The coordinates of these two points correspond to the coordinates of the virtual sensor. To give a specific example, in the example shown in Figure 8A, we determine the internal division point P1 between the upwind flow velocity sensors 14_X2 and 14_Y1, and the internal division point P2 between the downwind flow velocity sensors 14_X1 and 14_Y2. The specific calculation method for the internal division point P1 will be explained below. The ratio of internal division point P1 (m1:n1) is calculated from the flow velocity value Vx2 from flow velocity sensor 14_X2 and the flow velocity value Vy1 from flow velocity sensor 14_Y1 according to equations (5) and (6) below. m1 = Vx² / (Vx² + Vy1) ... (5) n1 = Vy1 / (Vx2 + Vy1) ... (6) Next, the coordinates of the internal division point P1 are calculated from the calculated ratios m1 and m2, the coordinate values ​​of the flow velocity sensor 14_X2 (X_x2, Y_x2), and the coordinate values ​​of the flow velocity sensor 14_Y1 (X_y1, Y_y1) according to equation (7) below.

number

number

[0062] Next, we find the equation of the line perpendicular to line segment P1P2 and passing through the coordinates (X_c2, Y_c2) of point C2 of gas sensor 12_2. That is, we find the equation of the line that intersects line segment P1P2 perpendicularly from coordinate point C2 of gas sensor 12_2. If the slope of the equation where the line segments intersect perpendicularly is e and the y-intercept is f, then the perpendicularly intersecting line can be found from equation (10) below. y = ex + f ... (10)

[0063] Assuming a perpendicular condition, the product of the slopes is c·e = -1, so we can find the slope e in equation (10) as e = -1 / c. By substituting this slope e and the coordinates of C2 (X_c2, Y_c2) into equation (10), we can calculate the intercept f. Furthermore, by substituting these calculation results into the system of equations (9) and (10), we can calculate the X-coordinate X_p3 of coordinate point P3, and by substituting the calculated X_p3 into equation (10), we can calculate the Y-coordinate Y_p3 of coordinate point P3. In other words, the coordinates (X_p3, Y_p3) of the intersection point P3 between the line segment P1P2 and the perpendicular line from C2 are calculated. Then, using the coordinates of the internal division point P1 and the intersection point P3, the distance L2 between the internal division point P1 and the intersection point P3 can be calculated from equation (11) below. That is, the distance L2 along the wind direction of the gas sensor 12_2 can be calculated (step S118).

number

[0064] Furthermore, in the example shown in Figure 8A, the coordinate point C1 of gas sensor 12_1 and the coordinate point C4 of gas sensor 12_4 are points on the line segment P1P2. Therefore, the distance L1 along the wind direction of gas sensor 12_1 can be similarly calculated using the coordinates (X_c1, Y_c1) of the internal division point P1 and coordinate point C1. In addition, the distance L4 along the wind direction of gas sensor 12_4 can be similarly calculated using the coordinates (X_c4, Y_c4) of the internal division point P1 and coordinate point C4 (step S118).

[0065] Furthermore, Figure 8C is a graph showing the relationship between the positions of coordinate points P1 to P3 in Figure 8A and the concentration attenuation coefficient. In Figure 8C, the horizontal axis represents the distance in the XY direction, and the vertical axis represents the concentration attenuation coefficient. As shown in Figure 8C, focusing on the gas sensor 12_2, the distance L2 along the wind direction of the gas sensor 12_2 is known, so the concentration attenuation coefficient on the gas sensor 12_2 can be calculated from equation (2) above. This allows the sensor output correction value, which is the correction value for the output value of the gas sensor 12_2, to be calculated from equation (1) above (step S118). Similarly, the concentration attenuation coefficient and sensor output correction value can be calculated for the other gas sensors 12. [Effects of the First Embodiment]

[0066] As described above, the sensor system 100 according to the first embodiment includes gas sensors 12_1 to 12_4 arranged in an array in the center of the front surface of a substrate 10 having a front surface and a back surface, which react to gas in a gas and output a value corresponding to the gas concentration. The gas sensors 12_1 to 12_4 are arranged in a 2x2 array, with each gas sensor 12 spaced apart from other adjacent gas sensors 12. The sensor system 100 further includes a flow velocity sensor 14_X1 positioned on the +X direction side of gas sensors 12_2 and 12_4 on the surface of the substrate 10 with respect to the placement positions of gas sensors 12_1 to 12_4, which outputs a value related to the gas flow velocity; a flow velocity sensor 14_X2 positioned on the -X direction side of gas sensors 12_1 and 12_3; a flow velocity sensor 14_Y1 positioned on the +Y direction side of gas sensors 12_1 and 12_2; and a flow velocity sensor 14_Y2 positioned on the -Y direction side of gas sensors 12_3 and 12_4. Furthermore, the system includes a measuring instrument 2 that measures the output values ​​of gas sensors 12_1 to 12_4 and the output values ​​of flow velocity sensors 14_X1, 14_X2, 14_Y1, and 14_Y2, and a processing device 3 that corrects the output values ​​of gas sensors 12_1 to 12_4 based on the output values ​​of flow velocity sensors 14_X1, 14_X2, 14_Y1, and 14_Y2 measured by the measuring instrument 2.

[0067] With this configuration, it is possible to determine whether or not a gas concentration gradient exists on gas sensors 12_1 to 12_4 based on the differences in flow velocity values ​​detected by flow velocity sensors 14_X1, 14_X2, 14_Y1, and 14_Y2. In addition, if a concentration gradient exists, corrections corresponding to the position of each gas sensor 12 can be made based on the differences in flow velocity values ​​of each flow velocity sensor 14. As a result, the decrease in gas measurement accuracy due to the concentration gradient can be reduced.

[0068] Furthermore, the sensor system 100 according to the first embodiment has flow velocity sensors 14_X1, 14_X2, 14_Y1, and 14_Y2 that output flow velocity values ​​with a sign corresponding to the wind direction. In addition, the processing unit 3 has a function to detect the wind direction based on the sign of the flow velocity value detected by the flow velocity sensor 14, and a function to correct the outputs of gas sensors 12_1 to 12_4 based on the detected wind direction and the outputs of each flow velocity sensor 14.

[0069] With this configuration, the wind direction of the gas containing the gas can be determined, and it is known that the concentration diffuses and decreases downwind compared to upwind. Therefore, the output values ​​can be appropriately corrected according to the relative positions of the upwind and downwind sides of the gas sensors 12_1 to 12_4. As a result, the decrease in gas measurement accuracy due to the concentration gradient can be further reduced.

[0070] Furthermore, the sensor system 100 according to the first embodiment can set reference points on the upstream and downstream sides in the direction of the gas airflow, calculate the distance of each gas sensor 12 along the airflow direction from the upstream or downstream reference point, and correct the output values ​​of gas sensors 12_1 to 12_4 based on the calculated distance and the output values ​​of flow velocity sensors 14_X1, 14_X2, 14_Y1, and 14_Y2. With this configuration, the output values ​​of gas sensors 12_1 to 12_4 can be corrected with an appropriate correction amount corresponding to the distance from the reference point and the wind speed at each sensor position, thereby further reducing the decrease in gas measurement accuracy due to concentration gradients. [Correspondence in the first embodiment] In the first embodiment, gas sensors 12_2 and 12_3 and gas sensors 12_1 and 12_2 correspond to the first gas sensor, and gas sensors 12_1 and 12_3 and gas sensors 12_3 and 12_4 correspond to the second gas sensor.

[0071] Furthermore, in the first embodiment, the flow velocity sensors 14_X1 and 14_Y1 correspond to the first fluid sensors, the flow velocity sensors 14_X2 and 14_Y2 correspond to the second fluid sensors, the correction unit 30 of the processing unit 3 corresponds to the correction unit, and the wind direction determination unit 301 of the processing unit 3 corresponds to the flow direction detection unit. [Second Embodiment] Next, a second embodiment of the present invention will be described. Figure 9 shows the second embodiment. 〔composition〕

[0072] The second embodiment differs from the first embodiment in that it has a ceiling member positioned opposite the surface of the substrate 10, and a flow velocity sensor 14 is placed on the ceiling surface of the ceiling member. Hereinafter, components similar to those in the first embodiment will be denoted by the same reference numerals, and their descriptions will be omitted as appropriate, while the different parts will be described in detail. Figure 9 is a schematic diagram showing the configuration of the sensor module 1A according to the second embodiment, where Figure 9(a) is a perspective view, Figure 9(b) is a plan view with the ceiling member 16 removed, and Figure 9(c) is a side view. The sensor system 100 according to the second embodiment is the sensor system 100 of the first embodiment, but with a sensor module 1A instead of sensor module 1.

[0073] As shown in Figures 9(a) to (c), the sensor module 1A according to the second embodiment has the addition of a ceiling member 16 and four column members 18 compared to the sensor module 1 of the first embodiment, and each flow velocity sensor 14 is placed on the ceiling surface 16f of the ceiling member 16 instead of the surface of the substrate 10. The ceiling member 16 has a rectangular parallelepiped shape and a ceiling surface 16f that faces the entire surface of the substrate 10. In other words, the ceiling member 16 covers the entire gas sensors 12_1 to 12_4 that are placed on the surface of the substrate 10. Each of the four column members 18 has one end fixed to one of the four corners of the ceiling surface 16f of the ceiling member 16, and the other end of each column member 18 is fixed to one of the four corners of the surface of the base plate 10, thereby supporting the ceiling member 16 on the base plate 10.

[0074] In the second embodiment, each flow velocity sensor 14 is positioned on the ceiling surface 16f of the ceiling member 16 opposite each gas sensor 12. Specifically, flow velocity sensor 14_X1 is positioned opposite parts of gas sensors 12_2 and 12_3, respectively, and flow velocity sensor 14_X2 is positioned opposite parts of gas sensors 12_1 and 12_4, respectively. Flow velocity sensor 14_Y1 is positioned opposite parts of gas sensors 12_1 and 12_2, respectively, and flow velocity sensor 14_Y2 is positioned opposite parts of gas sensors 12_3 and 12_4, respectively. The sensor system 100 according to the second embodiment differs only in the configuration of the sensor module 1A; the operation of the measuring instrument 2 and the various calculation processes using the coordinate information of each sensor in the processing unit 3 are the same as those in the first embodiment. [Effects of the second embodiment]

[0075] As described above, the sensor system 100 according to the second embodiment has a ceiling member 16 that covers the entirety of the gas sensors 12_1 to 12_4, which are arranged on the surface of the substrate 10, so that it can prevent wind from the Z-axis direction. Furthermore, since each flow velocity sensor 14 is positioned on the ceiling surface 16f of the ceiling member 16 opposite each gas sensor 12, the distance between the gas sensor 12 and the flow velocity sensor 14 is shorter compared to the configuration of the first embodiment. As a result, the accuracy of the estimated flow velocity on each gas sensor 12 can be improved. As a result, the accuracy of the concentration attenuation coefficient corresponding to each gas sensor 12 can be improved. [Correspondence in the second embodiment] In the second embodiment, gas sensors 12_2 and 12_3 and gas sensors 12_1 and 12_2 correspond to the first gas sensor, and gas sensors 12_1 and 12_3 and gas sensors 12_3 and 12_4 correspond to the second gas sensor.

[0076] Furthermore, in the second embodiment, the flow velocity sensors 14_X1 and 14_Y1 correspond to the first fluid sensor, the flow velocity sensors 14_X2 and 14_Y2 correspond to the second fluid sensor, the correction unit 30 of the processing unit 3 corresponds to the correction unit, and the wind direction determination unit 301 of the processing unit 3 corresponds to the flow direction detection unit. [Variation]

[0077] In the above embodiment, the flow velocity sensor 14 measures the flow velocity and wind direction of the gas containing the gas, and the output of the gas sensor 12 is corrected based on the measured flow velocity and wind direction. However, the system is not limited to this configuration. For example, instead of the flow velocity sensor 14, a flow sensor that outputs a value related to the flow rate of the gas may be used to measure the flow rate and flow direction (wind direction) of the gas containing the gas, and the output of the gas sensor 12 may be corrected based on the flow rate and wind direction.

[0078] Furthermore, in the above embodiments and their modifications, the gas sensor 12 was described using as an example a configuration in which it outputs the frequency change amount ΔF and the resistance change rate R0 / Rs as output values, but it is not limited to this configuration. For example, a configuration in which the frequency Fs after gas molecules have attached or the resistance Rs after gas molecules have attached are output values ​​may be used as output values, and a configuration in which these output values ​​are corrected may also be used.

[0079] Furthermore, in the above embodiment and its modified form, the flow velocity sensors 14 are arranged at the center of each of the four edges of the substrate 10, but the configuration is not limited to this. For example, the arrangement positions and number of sensors may be changed to other configurations, such as arranging four flow velocity sensors 14 at the four corners of the substrate instead of or in addition to the four at the center.

[0080] Furthermore, in the above embodiment and its modifications, the distance from the flow velocity sensor 14 or virtual sensor to each gas sensor 12 in the wind direction, and the coordinate points of the virtual sensor are calculated, but the configuration is not limited to this. For example, since the coordinates of each sensor on the substrate 10 are known, information on the wind direction corresponding to the combination of flow velocity values ​​detected by each flow velocity sensor 14, the coordinates of the virtual sensor, and information on the distance from the flow velocity sensor 14 or virtual sensor to each gas sensor 12 in the wind direction may be calculated in advance, and this information may be stored in the memory of the processing unit 3 for use. In this case, for the XY direction, information for multiple directions may be calculated in advance, and the one closest to the measured combination of flow velocity values ​​may be selected, and the information corresponding to the selected combination may be used. [Explanation of Symbols]

[0081] 1,1A…Sensor module, 2…Measuring instrument, 3…Processing device, 4…Output device, 10…Circuit board, 12_1~12_4…Gas sensors, 14_X1,14_X2,14_Y1,14_Y2…Flow velocity sensors, 16…Ceiling member, 16f…Ceiling surface, 18…Column member, 100…Sensor system

Claims

1. A first gas sensor that reacts to a gas in a gaseous state and outputs a value corresponding to the concentration of the gas, A second gas sensor is positioned away from the first gas sensor and reacts to the gas in the gaseous environment to output a value corresponding to the concentration of the gas. A first fluid sensor is positioned on the first gas sensor side relative to the arrangement positions of the first and second gas sensors, and outputs a value related to the flow rate or flow velocity of the gas, A second fluid sensor is positioned on the second gas sensor side relative to the arrangement positions of the first and second gas sensors, and outputs a value related to the flow rate or flow velocity of the gas. A correction unit that corrects the output of the first gas sensor and the output of the second gas sensor based on the output of the first fluid sensor and the output of the second fluid sensor, A sensor system equipped with the following features.

2. The system further includes a flow direction detection unit for detecting the flow direction of the gas, The sensor system according to claim 1, wherein the correction unit corrects the output of the first gas sensor and the output of the second gas sensor based on the flow direction detected by the flow direction detection unit and the output of the first fluid sensor and the output of the second fluid sensor.

3. The sensor system according to claim 2, wherein the correction unit sets reference points on the upstream and downstream sides in the flow direction of the gas, calculates the distance of the first gas sensor and the second gas sensor along the flow direction from the upstream or downstream reference point, and corrects the output of the first gas sensor and the output of the second gas sensor based on the calculated distance and the output of the first fluid sensor and the output of the second fluid sensor.

4. Having a substrate with a front surface and a back surface, The first gas sensor and the second gas sensor are arranged in the center of the surface of the substrate. The first fluid sensor is positioned on the surface of the substrate on the side of the first gas sensor and outside of the first gas sensor. The sensor system according to any one of claims 1 to 3, wherein the second fluid sensor is located on the surface of the substrate on the side of the second gas sensor and outside the second gas sensor.

5. A substrate having a front surface and a back surface, The system comprises a ceiling member having a ceiling surface facing the surface of the substrate, The first gas sensor and the second gas sensor are arranged on the surface of the substrate. The sensor system according to any one of claims 1 to 3, wherein one of the first fluid sensor and the second fluid sensor is positioned opposite to one of the first gas sensor and the second gas sensor on the ceiling surface, and the other of the first fluid sensor and the second fluid sensor is positioned opposite to the other of the first gas sensor and the second gas sensor on the ceiling surface.

6. A method for correcting the output of a gas sensor in a sensor module comprising: a first gas sensor that reacts to a gas in a gaseous state and outputs a value corresponding to the concentration of the gas; a second gas sensor positioned away from the first gas sensor and that reacts to a gas in a gaseous state and outputs a value corresponding to the concentration of the gas; a first fluid sensor positioned on the first gas sensor side relative to the positioning of the first and second gas sensors and that outputs a value relating to the flow rate or flow velocity of the gas; and a second fluid sensor positioned on the second gas sensor side relative to the positioning of the first and second gas sensors and that outputs a value relating to the flow rate or flow velocity of the gas. The process includes a step of correcting the output of the first gas sensor and the output of the second gas sensor based on the output of the first fluid sensor and the output of the second fluid sensor. Method for correcting the output of a gas sensor.

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