A gas sensor and a smart wearable device

Abstract

The application relates to the technical field of detection devices, in particular to a gas sensor and an intelligent wearable device, which comprises a detection module and a gas sensing capacitor and a humidity sensing capacitor collection device; the gas sensing capacitor and the humidity sensing capacitor are connected in series to form a bridge circuit, and the detection module is connected with a bridge midpoint of the bridge circuit; the bridge circuit is used for generating a midpoint output voltage according to a capacitance difference between a capacitance value of the gas sensing capacitor and a capacitance value of the humidity sensing capacitor, the capacitance value of the gas sensing capacitor is determined by the concentration of a to-be-detected gas and the concentration of water vapor, and the capacitance value of the humidity sensing capacitor is determined by the concentration of water vapor; and the detection module is used for collecting the midpoint output voltage and determining the gas concentration of the to-be-detected gas according to the midpoint output voltage. The application can reduce the influence of water vapor on the concentration detection of the to-be-detected gas.

Description

Technical Field

[0001] This application relates to the field of detection device technology, and in particular to a gas sensor and a smart wearable device. Background Technology

[0002] Gas concentration detection is crucial to prevent safety accidents caused by gas leaks, excessively high or low concentrations, and to ensure the safety of industrial production, public environments, and household life.

[0003] Currently, to detect the concentration of a specific gas in space, capacitive gas sensors are generally used. These sensors typically include a gas sensing capacitor and a detection module (e.g., an Application-Specific Integrated Circuit (ASIC) chip). The gas sensing capacitor, being a capacitive structure, utilizes the change in dielectric constant caused by the change in gas concentration between two plates, leading to a change in capacitance. This, in turn, causes a change in the voltage output of the gas sensing capacitor. The detection chip then outputs a corresponding concentration signal based on this voltage value, thus detecting the gas concentration. However, when water vapor suddenly enters between the plates, it also causes fluctuations in the dielectric constant, resulting in a change in capacitance. This alters the concentration signal output by the detection module, even though the actual concentration of the gas remains unchanged. Therefore, minimizing the impact of water vapor on the detection results of capacitive gas sensors is a pressing technical problem that needs to be solved. Summary of the Invention

[0004] The main objective of this application is to provide a gas sensor and a smart wearable device, which aims to solve the technical problem of how to reduce the influence of water vapor on the detection results of capacitive gas sensors in the prior art.

[0005] To achieve the above objectives, this application proposes a gas sensor, which includes: a detection module and a data acquisition device equipped with a gas sensing capacitor and a humidity sensing capacitor.

[0006] The gas sensing capacitor and the humidity sensing capacitor are connected in series to form a bridge circuit, and the detection module is connected to the midpoint of the bridge circuit.

[0007] The bridge circuit is used to generate a midpoint output voltage based on the capacitance difference between the capacitance value of the gas sensing capacitor and the capacitance value of the humidity sensing capacitor. The capacitance value of the gas sensing capacitor is determined by the concentration of the gas to be measured and the concentration of water vapor, and the capacitance value of the humidity sensing capacitor is determined by the concentration of water vapor.

[0008] The detection module is used to acquire the midpoint output voltage and determine the gas concentration of the gas to be tested based on the midpoint output voltage.

[0009] In one embodiment, the detection module is further configured to determine the gas concentration of the gas to be measured based on a preset proportional relationship and the midpoint output voltage, provided that the sensitivity of the gas sensing capacitor to the water vapor is the same as that of the humidity sensing capacitor to the water vapor.

[0010] In one embodiment, the number of bridge circuits is at least two, and each bridge circuit is arranged in parallel. The detection module is connected to the midpoint of each bridge circuit.

[0011] The detection module is also used to determine the midpoint voltage difference based on the midpoint output voltage of each of the midpoints;

[0012] The detection module is further configured to determine the gas concentration of the gas to be tested based on a preset proportional relationship and the midpoint voltage difference, provided that the sensitivity of the gas sensing capacitor to the water vapor is the same as that of the humidity sensing capacitor to the water vapor.

[0013] In one embodiment, the gas sensing capacitor includes: a first electrode plate, a second electrode plate, and a first substrate having a first pad;

[0014] The first electrode plate and the second electrode plate are disposed at intervals on the first substrate. Both the first electrode plate and the second electrode plate are electrically connected to the first pad. The first pad is also electrically connected to the humidity sensing capacitor and the detection module.

[0015] In one embodiment, the humidity sensing capacitor includes: a third electrode plate, a fourth electrode plate, a humidity-sensitive medium, and a second substrate having a second pad;

[0016] The third electrode plate and the fourth electrode plate are disposed on the second substrate at intervals. The humidity-sensitive medium is disposed between the third electrode plate and the fourth electrode plate. The third electrode plate and the fourth electrode plate are both electrically connected to the second pad. The second pad is also electrically connected to the gas sensing capacitor and the detection module.

[0017] In one embodiment, the acquisition device includes: a first electrode plate, a second electrode plate, a third electrode plate, a fourth electrode plate, a humidity-sensitive medium, and a base substrate with base pads;

[0018] The first electrode plate and the second electrode plate are disposed at intervals on the base substrate, and the third electrode plate and the fourth electrode plate are disposed at intervals on the base substrate. The pad is electrically connected to the second electrode plate, the third electrode plate and the detection module.

[0019] The humidity-sensitive medium is disposed between the first electrode plate and the second electrode plate, or between the third electrode plate and the fourth electrode plate.

[0020] In one embodiment, the first electrode plate, the second electrode plate, the third electrode plate, and the fourth electrode plate are sequentially and spaced apart on the base substrate.

[0021] In one embodiment, the acquisition device includes: a first electrode plate, a second electrode plate, a third electrode plate, a fourth electrode plate, a first insulating layer, a second insulating layer, a humidity-sensitive medium, and a base substrate;

[0022] The first insulating layer is disposed on the base substrate. The second electrode plate and the fourth electrode plate are both disposed on the base substrate and are located on opposite sides of the first insulating layer, respectively. The first electrode plate is spaced apart from the second electrode plate on the side facing away from the base substrate, and the third electrode plate is spaced apart from the fourth electrode plate on the side facing away from the base substrate. The second insulating layer is disposed between the first electrode plate and the second electrode plate, and between the third electrode plate and the fourth electrode plate.

[0023] The humidity-sensitive medium is disposed between the first electrode plate and the second electrode plate, or between the third electrode plate and the fourth electrode plate.

[0024] In one embodiment, the gas sensor further includes: a substrate and a housing;

[0025] A cavity is formed inside the housing, and the housing is sleeved on the substrate. The detection module and the acquisition device are both disposed in the cavity.

[0026] The shell has ventilation holes.

[0027] In addition, to achieve the above objectives, this application also proposes a smart wearable device, which includes the gas sensor as described above.

[0028] This application discloses a gas sensor and a smart wearable device. The gas sensor includes: a detection module and a data acquisition device equipped with a gas sensing capacitor and a humidity sensing capacitor; the gas sensing capacitor and the humidity sensing capacitor are connected in series to form a bridge circuit, and the detection module is connected to the midpoint of the bridge circuit; the bridge circuit is used to generate a midpoint output voltage based on the capacitance difference between the capacitance values ​​of the gas sensing capacitor and the humidity sensing capacitor, wherein the capacitance value of the gas sensing capacitor is determined by the concentration of the gas to be measured and the concentration of water vapor, and the capacitance value of the humidity sensing capacitor is determined by the concentration of water vapor; the detection module is used to acquire the midpoint output voltage and determine the gas concentration of the gas to be measured based on the midpoint output voltage.

[0029] In this application, the acquisition device may include a gas sensing capacitor and a humidity sensing capacitor. The gas sensing capacitor and the humidity sensing capacitor are connected in series to form a bridge circuit. The detection module is connected to the midpoint of the bridge circuit. The capacitance value of the gas sensing capacitor is determined by the concentration of the gas to be measured and the concentration of water vapor, while the capacitance value of the humidity sensor is determined by the concentration of water vapor. Therefore, in actual detection, the capacitance value of the gas sensing capacitor can characterize the concentration of the gas to be measured and the concentration of water vapor, while the capacitance value of the humidity sensing capacitor can characterize the concentration of water vapor. The capacitance difference can characterize the concentration of the gas to be measured and the difference between the concentrations of water vapor and water vapor. The bridge circuit can generate a corresponding midpoint output voltage based on this capacitance difference. The detection module can acquire this midpoint output voltage and determine the gas concentration of the gas to be measured based on it. Because this application includes a humidity sensing capacitor for detecting water vapor concentration, the influence of water vapor is offset by forming a bridge circuit in series with the gas sensing capacitor, thereby reducing the impact of water vapor on the detection of the concentration of the gas to be measured. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0031] Figure 1 This is a structural block diagram of the first embodiment of the gas sensor proposed in this application.

[0032] Figure 2 This is a schematic diagram of the structure of the gas sensing capacitor in the first embodiment of the gas sensor proposed in this application.

[0033] Figure 3 This is a schematic diagram of the structure of the humidity sensing capacitor in the first embodiment of the gas sensor proposed in this application.

[0034] Figure 4 This is a schematic diagram of the structure of the first embodiment of the gas sensor proposed in this application;

[0035] Figure 5 This is a structural block diagram of the second embodiment of the gas sensor proposed in this application.

[0036] Figure 6 This is a schematic diagram of the acquisition device in the third embodiment of the gas sensor proposed in this application.

[0037] Figure 7This is another structural schematic diagram of the data acquisition device in the third embodiment of the gas sensor proposed in this application;

[0038] Figure 8 This is a schematic diagram of the acquisition device in the fourth embodiment of the gas sensor proposed in this application.

[0039] Explanation of icon numbers:

[0040] Cs humidity sensing capacitor 16 second substrate Cq gas sensing capacitor 17 humidity sensitive medium 1 bridge circuit 18 substrate 2 detection module 19 vent hole 11 first electrode plate 20 housing 12 second electrode plate 21 base substrate 13 first substrate 22 first insulating layer 14 third electrode plate 23 second insulating layer 15 fourth electrode plate

[0041] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0042] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0044] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0045] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0046] It should be noted that gas concentration detection is crucial in order to prevent safety accidents caused by gas leaks, excessively high or low concentrations, and to ensure the safety of industrial production, public environments, and household life.

[0047] Currently, to detect the concentration of a specific gas in space, capacitive gas sensors are generally used. These sensors typically include a gas sensing capacitor and a detection module (e.g., an Application-Specific Integrated Circuit (ASIC) chip). The gas sensing capacitor, being a capacitive structure, utilizes the change in dielectric constant caused by the change in gas concentration between two plates, leading to a change in capacitance. This, in turn, causes a change in the voltage output of the gas sensing capacitor. The detection chip then outputs a corresponding concentration signal based on this voltage value, thus detecting the gas concentration. However, when water vapor suddenly enters between the plates, it also causes fluctuations in the dielectric constant, resulting in a change in capacitance. This alters the concentration signal output by the detection module, even though the actual concentration of the gas remains unchanged. Therefore, minimizing the impact of water vapor on the detection results of capacitive gas sensors is a pressing technical problem that needs to be solved.

[0048] To address the aforementioned technical problems, this embodiment provides a gas sensor. The gas sensor's data acquisition device may include a gas sensing capacitor and a humidity sensing capacitor. These two capacitors are connected in series to form a bridge circuit. The detection module is connected to the midpoint of the bridge circuit. The capacitance value of the gas sensing capacitor is determined by the concentration of the gas to be measured and the concentration of water vapor, while the capacitance value of the humidity sensor is determined by the concentration of water vapor. Therefore, in actual detection, the capacitance value of the gas sensing capacitor represents the concentration of the gas to be measured and the concentration of water vapor, while the capacitance value of the humidity sensing capacitor represents the concentration of water vapor. The capacitance difference represents the concentration of the gas to be measured and the difference between the concentrations of water vapor and water vapor. The bridge circuit generates a corresponding midpoint output voltage based on this capacitance difference. The detection module acquires this midpoint output voltage and determines the gas concentration of the gas to be measured based on it. Because this embodiment includes a humidity sensing capacitor for detecting water vapor concentration, the influence of water vapor is offset by forming a bridge circuit with the gas sensing capacitor, thereby reducing the impact of water vapor on the detection of the gas concentration.

[0049] For ease of understanding, the following is combined with Figures 1 to 8 The gas sensor provided in the embodiments of this application will be described in detail.

[0050] Reference Figure 1 , Figure 1 This is a structural block diagram of the first embodiment of the gas sensor proposed in this application.

[0051] like Figure 1 As shown, in this embodiment, the gas sensor may include: a detection module 2 and a data acquisition device equipped with a gas sensing capacitor Cq and a humidity sensing capacitor Cs.

[0052] It should be noted that the gas sensor in this embodiment can be used in any scenario where the concentration of the gas to be measured needs to be detected, and this embodiment does not limit it.

[0053] It should also be noted that the detection module 2 mentioned above can be any module with integrated circuits, such as ASIC chips, or it can be a module with other devices that can implement the device in this embodiment. This embodiment does not limit this.

[0054] It is understood that the gas sensing capacitor Cq mentioned above can be a capacitor used to detect the concentration of the gas to be measured, and the humidity sensing capacitor Cs mentioned above can be a capacitor used to detect the concentration of water vapor.

[0055] Continue as Figure 1 As shown, in this embodiment, the gas sensing capacitor Cq and the humidity sensing capacitor Cs are connected in series to form a bridge circuit 1, and the detection module 2 is connected to the midpoint of the bridge circuit 1.

[0056] It should be understood that in this embodiment, a half-bridge circuit 1 can be formed by connecting the gas sensing capacitor Cq and the humidity sensing capacitor Cs in series. The connection point between the gas sensing capacitor Cq and the humidity sensing capacitor Cs can be used as the midpoint of the bridge circuit, and the detection module 2 can be connected through this midpoint.

[0057] Specifically, one end of any one of the capacitors can be connected to the power supply, the other end of the capacitor can be connected to one end of another capacitor, the other end of the other capacitor can be grounded, and then the point where the capacitor and the other capacitor are connected can be used as the midpoint of the bridge circuit and connected to the detection module 2.

[0058] As one implementation method, such as Figure 1 As shown, in this embodiment, the first terminal of the humidity sensing capacitor Cs can be connected to the power supply, the second terminal of the humidity sensing capacitor Cs can be connected to the first terminal of the gas sensing capacitor Cq, the second terminal of the gas sensing capacitor Cq can be grounded, and the point connecting the second terminal of the humidity sensing capacitor Cs and the first terminal of the gas sensing capacitor Cq can be used as the midpoint of the bridge circuit (i.e., Figure 1 Connect the midpoint of the bridge to the detection module 2 (n points).

[0059] In order to obtain the concentration of the gas to be measured, the bridge circuit 1 is used to generate a midpoint output voltage based on the capacitance difference between the capacitance value of the gas sensing capacitor Cq and the capacitance value of the humidity sensing capacitor Cs. The capacitance value of the gas sensing capacitor Cq is determined by the concentration of the gas to be measured and the concentration of water vapor, and the capacitance value of the humidity sensing capacitor Cs is determined by the concentration of water vapor.

[0060] The detection module 2 is used to collect the midpoint output voltage and determine the gas concentration of the gas to be tested based on the midpoint output voltage.

[0061] It should be noted that the above-mentioned midpoint output voltage can be the voltage at the midpoint of the bridge circuit 1.

[0062] It should also be noted that a typical capacitor may include two plates, which are arranged opposite each other and filled with a dielectric material (or not filled) to form a capacitor. The formula for calculating the capacitance value can be C = ε * S / d, where C is the capacitance value, ε is the dielectric constant, which can be used to reflect the dielectric properties of the dielectric between the two plates, S is the area of ​​the two plates, and d is the distance between the two plates.

[0063] As can be seen from the above, the capacitance value of a capacitor is directly proportional to the dielectric. If the gases between the two plates are different and / or have different concentrations, the dielectric constant will change, thus changing the capacitance value. The gas concentration can then be determined based on the capacitance value.

[0064] In this embodiment, the space between the plates of the gas sensing capacitor Cq can be configured to allow both the gas to be measured and water vapor to enter. Therefore, the capacitance value of the gas sensing capacitor Cq can change with the concentration of the gas to be measured and the concentration of water vapor. This can also be understood as the factors affecting the capacitance value of the gas sensing capacitor Cq including the concentration of the gas to be measured and the concentration of water vapor. Similarly, the space between the plates of the humidity sensing capacitor Cs can be configured to allow only water vapor to enter. Therefore, the capacitance value of the humidity sensing capacitor Cs changes only with the concentration of water vapor. This can also be understood as the factors affecting the capacitance value of the humidity sensing capacitor Cs including the concentration of water vapor.

[0065] Based on this, when powered by a power supply and only the gas to be detected is present, the gas will only enter the space between the plates of the gas sensing capacitor Cq, thus changing the capacitance of Cq and the voltage across it. However, since the gas cannot enter the space between the plates of the humidity sensing capacitor Cs, the capacitance of Cs remains unchanged, and the voltage across it remains constant. The capacitance difference between the gas sensing capacitor Cq and the humidity sensing capacitor Cs increases with the concentration of the gas to be detected, and this change in capacitance difference leads to a change in the midpoint output voltage of the bridge circuit. Therefore, the detection module 2 can acquire this midpoint output voltage and calculate the gas concentration based on a certain proportional relationship.

[0066] When only water vapor is present, it enters the space between the plates of the gas sensing capacitor Cq and the humidity sensing capacitor Cs, causing a change in the capacitance of Cq. However, this change differs from the change when the gas to be measured is present. Therefore, the voltage across Cq changes, but not in the same way as when only the gas to be measured is present. The capacitance of Cs also changes, specifically in accordance with the effect of water vapor under normal conditions. Thus, the capacitance difference between Cq and Cs also changes, but less than the change when only the gas to be measured is present (because Cs also changes). This change in capacitance difference leads to a change in the midpoint output voltage of the bridge circuit. The detection module 2 can then acquire this midpoint output voltage and calculate the gas concentration of the gas to be measured based on this voltage using a different proportional relationship.

[0067] It should be emphasized that the above proportional relationships can all be obtained through prior testing, and this embodiment does not impose any restrictions on them.

[0068] In practical use, the capacitance value of the gas sensing capacitor Cq can characterize the concentration of the gas to be measured and the concentration of water vapor, while the capacitance value of the humidity sensing capacitor Cs can characterize the concentration of water vapor. The capacitance difference can characterize the concentration of the gas to be measured and the difference between the concentrations of water vapor and water vapor. Bridge circuit 1 can generate a corresponding midpoint output voltage based on this capacitance difference. Detection module 2 can acquire this midpoint output voltage and determine the gas concentration of the gas to be measured based on it. Since this embodiment includes a humidity sensing capacitor Cs for detecting water vapor concentration, it forms a bridge circuit 1 in series with the gas sensing capacitor Cq to counteract the influence of water vapor, thereby reducing the impact of water vapor on the detection of the concentration of the gas to be measured.

[0069] Furthermore, considering that when water vapor is present, in order to facilitate the detection of the gas concentration of the gas to be tested, in this embodiment, the detection module 2 is also used to determine the gas concentration of the gas to be tested according to a preset proportional relationship and the midpoint output voltage when the sensitivity of the gas sensing capacitor Cq to the water vapor is the same as the sensitivity of the humidity sensing capacitor Cs to the water vapor.

[0070] It should be noted that, in this embodiment, when selecting the gas sensing capacitor Cq and the humidity sensing capacitor Cs, capacitors with the same sensitivity to water vapor can be selected. The sensitivity of the gas sensing capacitor Cq to water vapor can be the degree of influence of water vapor on the dielectric constant of the gas sensing capacitor Cq, and the sensitivity of the humidity sensing capacitor Cs to water vapor can be the degree of influence of water vapor on the dielectric constant of the humidity sensing capacitor Cs.

[0071] It should also be noted that the above-mentioned preset proportional relationship can be the relationship between the midpoint output voltage and the concentration of the gas to be measured. This preset proportional relationship can characterize the influence of the voltage value of the gas sensing capacitor Cq on the concentration of the gas to be measured.

[0072] It should be understood that continued integration Figure 1 Let the power supply voltage be denoted as V, the midpoint output voltage as Vm, the capacitance of the humidity sensing capacitor Cs as C1, and C1 = ε1*S1 / d1, where ε1 is the dielectric constant of the humidity sensing capacitor Cs, S1 is the plate area of ​​the humidity sensing capacitor Cs, and d1 is the distance between the plates of the humidity sensing capacitor Cs. Let the capacitance of the gas sensing capacitor Cq be denoted as C2, and C2 = ε2*S2 / d2, where ε2 is the dielectric constant of the gas sensing capacitor Cq, S2 is the plate area of ​​the gas sensing capacitor Cq, and d2 is the distance between the plates of the gas sensing capacitor Cq. Therefore, the midpoint output voltage Vm = C1 / (C1+C2)*V.

[0073] When the sensitivity of the gas sensing capacitor Cq to water vapor is the same as that of the humidity sensing capacitor Cs to water vapor, then ε1 = ε2. Substituting C1, C2, and ε1 = ε2 into Vm = C1 / (C1 + C2) * V, it can be found that the dielectric constant is canceled out, and the midpoint output voltage remains unchanged. When water vapor enters, it does not affect the detection module 2. The detection module 2 can then continue to determine the gas concentration of the gas to be detected based on the preset proportional relationship (the relationship between Vm and the gas concentration of the gas to be detected) and the midpoint output voltage.

[0074] Furthermore, in order to set the aforementioned gas sensing capacitor Cq, refer to Figure 2 , Figure 2 This is a schematic diagram of the structure of the gas sensing capacitor Cq in the first embodiment of the gas sensor proposed in this application. Figure 2 As shown, in this embodiment, the gas sensing capacitor Cq includes: a first electrode 11, a second electrode 12, and a first solder pad ( Figure 2 The first base 13 (not shown in the image);

[0075] The first electrode plate 11 and the second electrode plate 12 are disposed at intervals on the first substrate 13. The first electrode plate 11 and the second electrode plate 12 are both electrically connected to the first pad. The first pad is also electrically connected to the humidity sensing capacitor Cs and the detection module 2.

[0076] It should be noted that the first electrode plate 11 and the second electrode plate 12 mentioned above can be conductive plates used to form a capacitor in a capacitor. They can generally be made of metal materials, such as gold or aluminum. This embodiment does not limit this.

[0077] It should also be noted that the first substrate 13 can be a structure for supporting and hosting metal traces, and can be made of materials such as silicon. The first pad can be a metal area for making electrical connections, and can be made of conductive materials such as copper.

[0078] Understandably, in this embodiment, one side of the first electrode plate 11 and one side of the second electrode plate 12 can be disposed on the same side of the first substrate 13, and the first electrode plate 11 and the second electrode plate 12 are arranged parallel to each other and spaced apart. Several first pads (e.g., two) can also be disposed on the first substrate 13. One first pad can be connected to the first electrode plate 11 via a metal trace, and the other first pad can be connected to the second electrode plate 12 via a metal trace, serving as the first and second terminals of the gas sensing capacitor Cq, respectively. Then, one of the first pads can be electrically connected to the humidity sensing capacitor Cs to form a bridge circuit 1, whereby the electrode plate connected to this first pad is the positive electrode plate. The other first pad is electrically connected to the reference ground, whereby the electrode plate connected to this first pad is the negative electrode plate. The first pad connected to the humidity sensing capacitor Cs can also be electrically connected to the detection module 2 to output a midpoint output voltage.

[0079] Therefore, in actual use, whether the gas to be detected or water vapor enters between the first electrode plate 11 and the second electrode plate 12, its dielectric constant will change, and thus the capacitance value of the gas sensing capacitor Cq will change.

[0080] Furthermore, in order to set the humidity sensing capacitor Cs as described above, refer to Figure 3 , Figure 3 This is a schematic diagram of the structure of the humidity sensing capacitor Cs in the first embodiment of the gas sensor proposed in this application, as shown below. Figure 3 As shown, in this embodiment, the humidity sensing capacitor Cs includes: a third electrode 14, a fourth electrode 15, a humidity-sensitive medium 17, and a second pad ( Figure 3 The second substrate 16 (not shown in the image);

[0081] The third electrode plate 14 and the fourth electrode plate 15 are spaced apart on the second substrate 16. The humidity-sensitive medium 17 is disposed between the third electrode plate 14 and the fourth electrode plate 15. The third electrode plate 14 and the fourth electrode plate 15 are both electrically connected to the second pad. The second pad is also electrically connected to the gas sensing capacitor Cq and the detection module 2.

[0082] It should be understood that the third plate 14 and the fourth plate 15 mentioned above can be conductive plates used to form a capacitor in a capacitor, and can generally be made of metal materials, such as gold, aluminum, etc. This embodiment does not limit this.

[0083] It should also be understood that the second substrate 16 can be a structure for supporting and providing metal traces, and can be made of materials such as silicon. The second pad can be a metal area for making electrical connections, and can be made of conductive materials such as copper.

[0084] Understandably, in this embodiment, one side of the third electrode plate 14 and one side of the fourth electrode plate 15 can be disposed on the same side of the second substrate 16, and the third electrode plate 14 and the fourth electrode plate 15 are arranged parallel to each other and spaced apart. Several second pads (e.g., two) can also be disposed on the second substrate 16. One second pad can be connected to the third electrode plate 14 via a metal trace, and the other second pad can be connected to the fourth electrode plate 15 via a metal trace, serving as the first and second terminals of the humidity sensing capacitor Cs, respectively. Then, one of the second pads can be electrically connected to the gas sensing capacitor Cq to form a bridge circuit 1, whereby the electrode plate connected to this second pad is the negative electrode plate. The other second pad is electrically connected to the power supply, whereby the electrode plate connected to this second pad is the positive electrode plate. The second pad connected to the gas sensing capacitor Cq can also be electrically connected to the detection module 2 to output a midpoint output voltage.

[0085] It should be emphasized that the aforementioned humidity-sensitive medium 17 can be a medium sensitive to water vapor, such as polymers, ceramics, etc., and this embodiment does not limit it. In this embodiment, the humidity-sensitive medium 17 can be disposed between the third electrode plate 14 and the fourth electrode plate 15, and in order to ensure that only water vapor enters, the gap between the third electrode plate 14 and the fourth electrode plate 15 can be completely filled.

[0086] Therefore, in actual use, since a sensitive medium is provided, only water vapor is allowed to enter between the third electrode plate 14 and the fourth electrode plate 15. That is, the capacitance value of the humidity sensing capacitor Cs will only change when water vapor is present.

[0087] Furthermore, in order to set up a gas sensor to detect the gas to be measured, refer to Figure 4 , Figure 4 This is a schematic diagram of the structure of the first embodiment of the gas sensor proposed in this application.

[0088] like Figure 4 As shown, in this embodiment, the gas sensor further includes: a substrate 18 and a housing 20;

[0089] A cavity is formed inside the housing 20, and the housing 20 is sleeved on the substrate 18. The detection module 2 and the acquisition device are both disposed in the cavity.

[0090] The housing 20 has ventilation holes 19.

[0091] It should be noted that the substrate 18 mentioned above can be any substrate 18 with load-bearing capacity, such as a circuit board, etc., and this embodiment does not limit it in this way.

[0092] It should also be noted that in this embodiment, the detection module 2 can be disposed on one side of the substrate 18, which can be done by adhesive bonding. Of course, other methods can also be used, and this embodiment does not limit this. The gas sensing capacitor Cq and humidity sensing capacitor Cs mentioned above can both be disposed on the side of the detection module 2 away from the substrate 18, which can also be done by adhesive bonding.

[0093] As another implementation, in this embodiment, the gas sensing capacitor Cq and the humidity sensing capacitor Cs can also be disposed directly on the substrate 18 instead of being stacked with the detection module 2. Of course, the specific arrangement can be set according to the actual situation, and this embodiment does not limit it.

[0094] It is understood that the aforementioned housing 20 can be any housing 20 with protective capabilities. In this embodiment, a vent 19 can be provided at any position on the housing 20, so that external gas can be transmitted into the housing 20 through the vent 19 for detection.

[0095] Furthermore, in order to prevent interference from moisture and other factors, this embodiment can also provide a waterproof and breathable membrane on the vent 19, so as to achieve the functions of waterproofing and breathability.

[0096] In this embodiment, the gas sensor's data acquisition device may include a gas sensing capacitor Cq and a humidity sensing capacitor Cs. The gas sensing capacitor Cq and the humidity sensing capacitor Cs are connected in series to form a bridge circuit 1. The detection module 2 is connected to the midpoint of the bridge circuit 1. The capacitance value of the gas sensing capacitor Cq is determined by the concentration of the gas to be measured and the concentration of water vapor, while the capacitance value of the humidity sensor is determined by the concentration of water vapor. Therefore, during actual detection, the capacitance value of the gas sensing capacitor Cq can characterize the concentration of the gas to be measured and the concentration of water vapor, while the capacitance value of the humidity sensing capacitor Cs can characterize the concentration of water vapor. The capacitance difference can characterize the concentration of the gas to be measured and the difference between the concentrations of water vapor and water vapor. The bridge circuit 1 can generate a corresponding midpoint output voltage based on this capacitance difference. The detection module 2 can acquire this midpoint output voltage and determine the gas concentration of the gas to be measured based on it. In this embodiment, a humidity sensing capacitor Cs is provided to detect the concentration of water vapor. By connecting it in series with the gas sensing capacitor Cq to form a bridge circuit 1, the influence of water vapor is offset, thereby reducing the impact of water vapor on the detection of the concentration of the gas to be measured.

[0097] Reference Figure 5 , Figure 5 This is a structural block diagram of a second embodiment of the gas sensor proposed in this application.

[0098] To improve the accuracy of detection, such as Figure 5 As shown, in this embodiment, the number of bridge circuits 1 is at least two, and each bridge circuit 1 is arranged in parallel. The detection module 2 is connected to the midpoint of each bridge circuit 1.

[0099] The detection module 2 is also used to determine the midpoint voltage difference based on the midpoint output voltage of each of the midpoints;

[0100] The detection module 2 is further configured to determine the gas concentration of the gas to be tested based on a preset proportional relationship and the midpoint voltage difference, when the sensitivity of the gas sensing capacitor Cq to the water vapor is consistent with the sensitivity of the humidity sensing capacitor Cs to the water vapor.

[0101] It should be noted that in this embodiment, multiple bridge circuits 1 can be provided, and all bridge circuits 1 are connected in parallel. For example... Figure 5 As shown, this embodiment uses two bridge circuits 1 connected in parallel for illustration. Since one bridge circuit 1 is a half-bridge, two bridge circuits 1 connected in parallel form a full bridge.

[0102] It should also be noted that when performing parallel connection, a portion of the gas sensing capacitor Cq of bridge circuit 1 can be connected to the power supply, and the humidity sensing capacitor Cs can be grounded. The other portion of the humidity sensing capacitor Cs of bridge circuit 1 can be connected to the power supply, and the gas sensing capacitor Cq can be grounded, thus forming a full bridge. The alternating method can improve the accuracy of detection.

[0103] For example, such as Figure 5 As shown, in this embodiment, the first terminal of the humidity sensing capacitor Cs in one bridge circuit 1 can be connected to the power supply, the second terminal of the humidity sensing capacitor Cs can be connected to the first terminal of the gas sensing capacitor Cq and the detection module 2, and the second terminal of the gas sensing capacitor Cq can be grounded; the first terminal of the gas sensing capacitor Cq in another bridge circuit 1 can be connected to the power supply, the second terminal of the gas sensing capacitor Cq can be connected to the first terminal of the humidity sensing capacitor Cs and the detection module 2, and the second terminal of the humidity sensing capacitor Cs can be grounded.

[0104] It should also be noted that the above-mentioned midpoint voltage difference can be the voltage difference between the output voltages at each midpoint, such as... Figure 5 As shown, if there are two midpoint output voltages, the midpoint voltage difference is the difference between the two midpoint output voltages. When there is a voltage higher than that of the two bridge circuits 1, the midpoint output voltage of the bridge circuit 1 connected to the power supply at the first terminal of the humidity sensing capacitor Cs can be collected and averaged to obtain the first average value. The midpoint output voltage of the bridge circuit 1 connected to the power supply at the first terminal of the gas sensing capacitor Cq can be collected and averaged to obtain the second average value. The difference between the first average value and the second average value is then calculated to obtain the midpoint voltage difference.

[0105] Understandably, the aforementioned preset proportional relationship can be a relationship between the midpoint voltage difference and the gas concentration of the gas to be measured, which can be obtained in advance through testing.

[0106] In practical use, after the detection module 2 obtains the midpoint output voltage of each bridge circuit 1, it can obtain the midpoint voltage difference based on the midpoint output voltage, and then use the above-mentioned preset proportional relationship to obtain the gas concentration of the gas to be detected.

[0107] Reference Figure 6 , Figure 6 This is a schematic diagram of the acquisition device in the third embodiment of the gas sensor proposed in this application.

[0108] like Figure 2 as well as Figure 3 As shown, when setting up the gas sensor, the gas sensing capacitor Cq can be integrated into one chip, and the humidity sensing capacitor Cs can be integrated into one chip, and then set separately (i.e., ...). Figure 4 (As shown). Alternatively, the gas sensing capacitor Cq and the humidity sensing capacitor Cs can be integrated into a single chip. For example, if two gas sensing capacitors Cq and two humidity sensing capacitors Cs are used to form a full bridge, then refer to... Figure 7 , Figure 7 This is another structural schematic diagram of the data acquisition device in the third embodiment of the gas sensor proposed in this application, as shown below. Figure 7 As shown, the gas sensing capacitors Cq and humidity sensing capacitors Cs can be evenly partitioned and integrated into a single chip on a substrate to serve as the aforementioned data acquisition device.

[0109] Of course, considering that setting the gas sensing capacitor Cq and the humidity sensing capacitor Cs as separate chips might make subsequent installation more complicated, an integrated approach can be adopted, such as... Figure 6 As shown, in this embodiment, the acquisition device includes: a first electrode plate 11, a second electrode plate 12, a third electrode plate 14, a fourth electrode plate 15, a humidity-sensitive medium 17, and a base pad ( Figure 6 The base 21 (not shown in the image) is a foundation base.

[0110] The first electrode plate 11 and the second electrode plate 12 are spaced apart on the base substrate 21, and the third electrode plate 14 and the fourth electrode plate 15 are spaced apart on the base substrate 21. The pad is electrically connected to the second electrode plate 12, the third electrode plate 14 and the detection module 2.

[0111] The humidity-sensitive medium 17 is disposed between the first electrode plate 11 and the second electrode plate 12, or between the third electrode plate 14 and the fourth electrode plate 15.

[0112] It should be noted that the first electrode plate 11 and the fourth electrode plate 15 mentioned above can be conductive plates used to form a capacitor in a capacitor. They can generally be made of metal materials, such as gold or aluminum. This embodiment does not limit this.

[0113] It should also be understood that the aforementioned base substrate 21 can be a structure for supporting and mounting metal traces, and can be made of materials such as silicon. The aforementioned base pads can be metal areas for making electrical connections, and can be made of conductive materials such as copper.

[0114] Understandably, in this embodiment, one side of the first electrode plate 11 and one side of the second electrode plate 12 can be disposed on the same side of the base substrate 21, and the first electrode plate 11 and the second electrode plate 12 are arranged parallel to each other and spaced apart. One side of the third electrode plate 14 and one side of the fourth electrode plate 15 are disposed on the same side of the base substrate 21, and the third electrode plate 14 and the fourth electrode plate 15 are arranged parallel to each other and spaced apart.

[0115] Furthermore, the humidity-sensitive medium 17 can be disposed between the first electrode 11 and the second electrode 12, or between the third electrode 14 and the fourth electrode 15. If it is disposed between the first electrode 11 and the second electrode 12, then the first electrode 11 and the second electrode 12 together form the electrode of the humidity sensing capacitor Cs, and the third electrode 14 and the fourth electrode 15 together form the electrode of the gas sensing capacitor Cq. If it is disposed between the third electrode 14 and the fourth electrode 15, then the third electrode 14 and the fourth electrode 15 together form the electrode of the humidity sensing capacitor Cs, and the first electrode 11 and the second electrode 12 together form the electrode of the gas sensing capacitor Cq. Figure 6 The description uses the plate located between the third plate 14 and the fourth plate 15.

[0116] It is also understood that, in order to form a half-bridge, in this embodiment, either plate of the gas sensing capacitor Cq and either plate of the humidity sensing capacitor Cs can be connected by metal traces and connected to the above-mentioned base pads to connect to the detection module 2.

[0117] like Figure 6 As shown, in this embodiment, the second electrode plate 12 and the third electrode plate 14 can be connected by metal traces and electrically connected to a base pad, thereby electrically connecting to the detection module 2. Simultaneously, a base pad can be connected to the first electrode plate 11 via metal traces for receiving power or grounding, and another base pad can be connected to the fourth electrode plate 15 via metal traces for grounding or receiving power. Specific details can be found in the embodiments described above, and will not be elaborated upon here.

[0118] In practical use, this embodiment can integrate the gas sensing capacitor Cq and the humidity sensing capacitor Cs into a single chip, which simplifies the installation process by allowing the entire chip to be installed directly during subsequent setup.

[0119] Furthermore, to facilitate the arrangement of the first to fourth electrode plates 11, the following steps are continued... Figure 6 As shown, in this embodiment, the first electrode plate 11, the second electrode plate 12, the third electrode plate 14 and the fourth electrode plate 15 are sequentially and spaced apart on the base substrate 21.

[0120] It should be emphasized that, in this embodiment, the first electrode plate 11 to the fourth electrode plate 15 can be arranged sequentially and at intervals on the base substrate 21, that is... Figure 6 As shown, this forms a comb-tooth capacitor.

[0121] Reference Figure 8 , Figure 8 This is a schematic diagram of the acquisition device in the fourth embodiment of the gas sensor proposed in this application.

[0122] As another way to achieve integration, such as Figure 8 As shown, in this embodiment, the acquisition device includes: a first electrode plate 11, a second electrode plate 12, a third electrode plate 14, a fourth electrode plate 15, a first insulating layer 22, a second insulating layer 23, a humidity-sensitive medium 17, and a base substrate 21.

[0123] The first insulating layer 22 is disposed on the base substrate 21. The second electrode plate 12 and the fourth electrode plate 15 are both disposed on the base substrate 21 and are respectively located on opposite sides of the first insulating layer 22. The first electrode plate 11 is disposed at a distance from the second electrode plate 12 on the side away from the base substrate 21. The third electrode plate 14 is disposed at a distance from the fourth electrode plate 15 on the side away from the base substrate 21. The second insulating layer 23 is disposed between the first electrode plate 11 and the second electrode plate 12, and between the third electrode plate 14 and the fourth electrode plate 15.

[0124] The humidity-sensitive medium 17 is disposed between the first electrode plate 11 and the second electrode plate 12, or between the third electrode plate 14 and the fourth electrode plate 15.

[0125] It should be noted that the first electrode plate 11 and the fourth electrode plate 15 mentioned above can be conductive plates used to form a capacitor in a capacitor. They can generally be made of metal materials, such as gold or aluminum. This embodiment does not limit this.

[0126] It should also be understood that the aforementioned base substrate 21 can be a structure for supporting and setting metal traces, and can be made of materials such as silicon.

[0127] It should also be noted that the first insulating layer 22 and the second insulating layer 23 mentioned above can be used for insulation, and can be made of insulating materials, such as silicon nitride, etc. This embodiment does not limit this.

[0128] Understandably, in this embodiment, a first insulating layer 22 can be provided at the top center of the base substrate 21, and the second and fourth electrodes can be provided on both sides of the first insulating layer 22. Then, the first electrode is spaced apart on the side of the second electrode away from the base substrate 21, and the second insulating layer 23 is provided therein with at least a partial cavity to accommodate gas. The third electrode is spaced apart on the side of the fourth electrode away from the base substrate 21, and the second insulating layer 23 is provided therein with at least a partial cavity to fill the moisture-sensitive medium 17.

[0129] It is also understood that in this embodiment, the gas sensing capacitor Cq and the humidity sensing capacitor Cs can be integrated in the form of a plate capacitor. For example... Figure 8 As shown, both the first electrode plate 11 and the third electrode plate 14 can be multi-segmented, with gaps in between to facilitate gas entry.

[0130] The first and second electrodes can be used to form the two plates of the gas sensing capacitor Cq, and the third and fourth electrodes can be used to form the two plates of the humidity sensing capacitor Cs. Electrical connections are then made according to the connection method described in the above embodiment, thereby integrating the gas sensing capacitor Cq and the humidity sensing capacitor Cs to form a bridge circuit 1.

[0131] In addition, to achieve the above objectives, this embodiment also provides a smart wearable device, which includes the gas sensor as described above.

[0132] The specific structure of the gas sensor can be referred to in the above embodiments. Since this smart wearable device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0133] The above are merely preferred embodiments of this application and do not limit the scope of protection of this application. Any equivalent structural or procedural transformations made based on the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of protection of this application.

Claims

1. A gas sensor, characterized in that, The gas sensor includes: a detection module and a data acquisition device equipped with a gas sensing capacitor and a humidity sensing capacitor. The gas sensing capacitor and the humidity sensing capacitor are connected in series to form a bridge circuit, and the detection module is connected to the midpoint of the bridge circuit. The bridge circuit is used to generate a midpoint output voltage based on the capacitance difference between the capacitance value of the gas sensing capacitor and the capacitance value of the humidity sensing capacitor. The capacitance value of the gas sensing capacitor is determined by the concentration of the gas to be measured and the concentration of water vapor, and the capacitance value of the humidity sensing capacitor is determined by the concentration of water vapor. The detection module is used to acquire the midpoint output voltage and determine the gas concentration of the gas to be tested based on the midpoint output voltage.

2. The gas sensor as described in claim 1, characterized in that, The detection module is further configured to determine the gas concentration of the gas to be tested based on a preset proportional relationship and the midpoint output voltage, provided that the sensitivity of the gas sensing capacitor to the water vapor is the same as that of the humidity sensing capacitor to the water vapor.

3. The gas sensor as described in claim 2, characterized in that, The number of bridge circuits is at least two, and each bridge circuit is arranged in parallel. The detection module is connected to the midpoint of each bridge circuit. The detection module is also used to determine the midpoint voltage difference based on the midpoint output voltage of each of the midpoints; The detection module is further configured to determine the gas concentration of the gas to be tested based on a preset proportional relationship and the midpoint voltage difference, provided that the sensitivity of the gas sensing capacitor to the water vapor is the same as that of the humidity sensing capacitor to the water vapor.

4. The gas sensor as described in claim 1, characterized in that, The gas sensing capacitor includes: a first electrode plate, a second electrode plate, and a first substrate having a first solder pad; The first electrode plate and the second electrode plate are disposed at intervals on the first substrate. Both the first electrode plate and the second electrode plate are electrically connected to the first pad. The first pad is also electrically connected to the humidity sensing capacitor and the detection module.

5. The gas sensor as described in claim 1, characterized in that, The humidity sensing capacitor includes: a third electrode plate, a fourth electrode plate, a humidity-sensitive dielectric, and a second substrate with a second pad. The third electrode plate and the fourth electrode plate are disposed on the second substrate at intervals. The humidity-sensitive medium is disposed between the third electrode plate and the fourth electrode plate. The third electrode plate and the fourth electrode plate are both electrically connected to the second pad. The second pad is also electrically connected to the gas sensing capacitor and the detection module.

6. The gas sensor as described in claim 1, characterized in that, The acquisition device includes: a first electrode plate, a second electrode plate, a third electrode plate, a fourth electrode plate, a humidity-sensitive medium, and a base substrate with a base pad; The first electrode plate and the second electrode plate are disposed at intervals on the base substrate, and the third electrode plate and the fourth electrode plate are disposed at intervals on the base substrate. The pad is electrically connected to the second electrode plate, the third electrode plate and the detection module. The humidity-sensitive medium is disposed between the first electrode plate and the second electrode plate, or between the third electrode plate and the fourth electrode plate.

7. The gas sensor as described in claim 6, characterized in that, The first electrode plate, the second electrode plate, the third electrode plate, and the fourth electrode plate are sequentially and spaced apart on the base substrate.

8. The gas sensor as described in claim 1, characterized in that, The data acquisition device includes: a first electrode plate, a second electrode plate, a third electrode plate, a fourth electrode plate, a first insulating layer, a second insulating layer, a humidity-sensitive medium, and a base substrate; The first insulating layer is disposed on the base substrate, the second electrode plate and the fourth electrode plate are both disposed on the base substrate and are respectively located on opposite sides of the first insulating layer. The first electrode plate is disposed at a distance from the second electrode plate on the side away from the base substrate, and the third electrode plate is disposed at a distance from the fourth electrode plate on the side away from the base substrate. The second insulating layer is disposed between the first electrode plate and the second electrode plate, and between the third electrode plate and the fourth electrode plate. The humidity-sensitive medium is disposed between the first electrode plate and the second electrode plate, or between the third electrode plate and the fourth electrode plate.

9. The gas sensor as described in any one of claims 1 to 8, characterized in that, The gas sensor also includes: a substrate and a housing; A cavity is formed inside the housing, and the housing is sleeved on the substrate. The detection module and the acquisition device are both disposed in the cavity. The shell has ventilation holes.

10. A smart wearable device, characterized in that, The smart wearable device includes a gas sensor as described in any one of claims 1 to 9.

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