Thermal flow sensor and gas flow detection method

Abstract

The application discloses a thermal flow sensor and a gas flow detection method. The thermal flow sensor comprises a flow measurement unit formed on the surface of a substrate, the flow measurement unit comprising an upstream thermosensitive element, a heating resistor and a downstream thermosensitive element arranged discretely in sequence; a compensation unit formed on the surface of the substrate, the compensation unit comprising an upstream ambient resistor located upstream of the flow measurement unit and a downstream ambient resistor located downstream of the flow measurement unit; the heating resistor is used for heating the upstream thermosensitive element and the downstream thermosensitive element by electrification; and the heating resistor is also used for heating one of the upstream ambient resistor and the downstream ambient resistor by electrification through flowing gas. The thermal flow sensor of the application can overcome the defect that the existing thermal flow sensor cannot perform temperature compensation on reverse gas flow, and can perform self-detection and judgment to verify the reliability of the sensor.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sensing, and particularly relates to a thermal flow sensor and a gas flow detection method. BACKGROUND

[0002] With the development of society, people have higher and higher requirements for sensors. For example, the sensors are required to have small size, fast response time, stable performance and the like. A thermal distributed MEMS flow sensor can meet the above requirements. The thermal flow sensor mainly comprises one heating resistor and two temperature measuring elements. The flow is measured according to the temperature difference between the upstream and downstream temperature measuring elements under different flow rates by keeping the constant power of the heating resistor. In order to suppress the influence of temperature change on detection, a temperature compensation resistor element for detecting the ambient temperature is arranged in the thermal flow sensor to implement temperature compensation. The temperature compensation resistor element is usually arranged upstream of the flow detection resistor element. However, when the fluid flows reversely, the temperature of the fluid is affected by the heating resistor, so that accurate compensation cannot be performed, and thus the reverse fluid cannot be detected. In addition, the existing thermal flow sensor is only subjected to quality detection at the factory, and quality problems occurring in the use process are difficult to find. SUMMARY

[0003] The purpose of the embodiments of the application is to provide a thermal flow sensor and a gas flow detection method, which can overcome the defect that the existing thermal flow sensor cannot perform temperature compensation on reverse airflow, and can perform self-detection and judgment to verify the reliability of the sensor.

[0004] In a first aspect, the application provides a thermal flow sensor for detecting gas flow, comprising:

[0005] a flow measurement unit formed on the surface of the substrate, the flow measurement unit comprising an upstream thermosensitive element, a heating resistor and a downstream thermosensitive element arranged in sequence and separately;

[0006] a compensation unit formed on the surface of the substrate, the compensation unit comprising an upstream ambient resistor located upstream of the flow measurement unit and a downstream ambient resistor located downstream of the flow measurement unit;

[0007] the heating resistor is used for heating the upstream thermosensitive element and the downstream thermosensitive element by power supply;

[0008] the heating resistor is also used for heating by power supply to heat one of the upstream ambient resistor and the downstream ambient resistor by flowing gas. When the resistance of one of the upstream ambient resistor and the downstream ambient resistor increases, the temperature corresponding to the resistance of the other one is the ambient temperature, which is used for compensation

[0009] Optionally, the thermal flow sensor further comprises:

[0010] a heat-conducting layer formed on a surface of the heating resistor and in contact with the hot ends of the upstream and downstream thermosensitive elements.

[0011] Optionally, the back surface of the substrate is provided with a cavity, which is located at a position corresponding to the heating resistor on the substrate.

[0012] Optionally, the hot ends of the upstream and downstream thermosensitive elements are located at a position corresponding to the cavity on the substrate.

[0013] Optionally, the substrate comprises a substrate, a surface of the substrate is provided with a support layer, the flow detection unit and the compensation unit are located on the support layer, and the back surface of the substrate is provided with the cavity and exposes the support layer.

[0014] Optionally, a through hole is provided on the heating resistor to form a parallel structure to reduce the resistance value of the heating resistor.

[0015] Optionally, the compensation unit is further used to generate high temperature by heating to remove water vapor and gas residues on the surface of the thermal flow sensor.

[0016] Optionally, the upstream and downstream ambient resistors are in a serpentine structure.

[0017] In a second aspect, the embodiment of the present application provides a gas flow detection method, which comprises a flow detection step, and the step specifically comprises:

[0018] determining the flow direction of the target gas flow;

[0019] determining whether the temperature of the thermosensitive element and the ambient resistor located downstream of the target gas flow increases simultaneously according to the determined flow direction of the target gas flow;

[0020] if yes, taking the temperature of the ambient resistor located upstream of the flowing gas as the ambient temperature to perform temperature compensation.

[0021] Optionally, after the flow detection, the method further comprises a cleaning step, and the step specifically comprises:

[0022] passing current through the compensation unit to generate high temperature by heating of the compensation unit to remove water vapor and gas residues on the surface of the thermal flow sensor.

[0023] According to a third aspect of the embodiment of the present application, an electronic device can comprise:

[0024] a processor;

[0025] a memory for storing processor-executable instructions;

[0026] The processor is configured to execute instructions to implement the gas flow detection method according to the second aspect of the embodiments of the present application.

[0027] According to a fourth aspect of the embodiments of the present application, a storage medium is provided, when instructions in the storage medium are executed by a processor of an information processing device or a server, the information processing device or the server is caused to implement the gas flow detection method according to the second aspect of the embodiments of the present application.

[0028] The above technical solutions of the present application have the following beneficial technical effects:

[0029] The thermal flow sensor according to the embodiments of the present application can overcome the defect that the existing thermal flow sensor cannot perform temperature compensation on reverse airflow, and realize bidirectional detection of airflow. Meanwhile, the thermal flow sensor according to the embodiments of the present application can also perform self-detection and judgment through temperature changes of two environmental resistors, and verify the reliability of the sensor. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a structural schematic diagram of a thermal flow sensor in an exemplary embodiment of the present application;

[0031] Figure 2 is a sectional view of a thermal flow sensor in an exemplary embodiment of the present application;

[0032] Figure 3 is a flowchart of a gas flow detection method in an exemplary embodiment of the present application;

[0033] Figure 4 is a hardware structural schematic diagram of an electronic device in an exemplary embodiment of the present application;

[0034] Figure 5 is a hardware structural schematic diagram of an electronic device according to an embodiment of the present application;

[0035] In the figure, 100 is an upstream thermosensitive element; 110 is an N+ type polysilicon thermocouple; 120 is a P+ type polysilicon thermocouple; 200 is a heating resistor; 210 is a through hole; 300 is a downstream thermosensitive element; 400 is an upstream environmental resistor; 500 is a downstream environmental resistor; 600 is a heat-conducting layer; 700 is a substrate; 710 is a substrate; 720 is a support layer; 721 is a silicon oxide layer; 722 is a silicon nitride layer; 730 is a cavity; 800 is a wire structure; 910 is an element protection layer; 920 is a chip protection layer; 1 is a first electrode; 2 is a second electrode; 3 is a third electrode; 4 is a fourth electrode; 5 is a fifth electrode; 6 is a sixth electrode; 7 is a seventh electrode; 8 is an eighth electrode; 9 is a ninth electrode; and 10 is a tenth electrode. DETAILED DESCRIPTION

[0036] For the purposes of the present application, technical solutions and advantages, the following will be further described in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of well-known structures and techniques is omitted to avoid unnecessary confusion of the concepts of the present application.

[0037] In the drawings, schematic diagrams of layer structures according to embodiments of the present application are shown. These diagrams are not drawn to scale, in which certain details are exaggerated for the purpose of clarity, and certain details can be omitted. The shapes of various regions, layers, and their relative sizes and positional relationships shown in the drawings are only exemplary, and in actuality can deviate due to manufacturing tolerances or technical limitations, and regions / layers with different shapes, sizes, relative positions can be additionally designed by those skilled in the art according to actual needs.

[0038] Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0039] In the description of the present application, it should be noted that the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0040] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0041] As Figures 1-2As shown, the embodiment of the present application provides a thermal flow sensor for detecting gas flow, comprising: a flow measurement unit formed on the surface of a substrate 700, the flow measurement unit comprising an upstream thermosensitive element 100, a heating resistor 200 and a downstream thermosensitive element 300 arranged discretely in sequence; a compensation unit formed on the surface of the substrate 700, the compensation unit comprising an upstream ambient resistor 400 located upstream of the flow measurement unit and a downstream ambient resistor 500 located downstream of the flow measurement unit; the heating resistor 200 is used to heat the upstream thermosensitive element 100 and the downstream thermosensitive element 300 by being energized; the heating resistor 200 is also used to generate heat by being energized to heat one of the upstream ambient resistor 400 and the downstream ambient resistor 500 through the flowing gas. In a specific application, when the gas flows from the upstream element to the downstream element, the gas flowing through will take away the heat of the upstream thermosensitive element 100 and the heating resistor 200, and heat the downstream thermosensitive element 300 and the downstream ambient resistor 500, at this time, the upstream ambient resistor 400 is not affected by the temperature, and the temperature of the upstream ambient resistor 400 can be used to determine the ambient temperature to compensate the detection result; similarly, when the gas flows from the downstream element to the upstream element, the gas flowing through will take away the heat of the downstream thermosensitive element 300 and the heating resistor 200, and heat the upstream thermosensitive element 100 and the upstream ambient resistor 400, at this time, the temperature of the downstream ambient resistor 500 can be used to determine the ambient temperature to compensate the detection result. As can be seen, when the thermal flow sensor of the embodiment of the present application is used to detect the gas flow, the upstream ambient resistor is not affected by the temperature change of the gas each time the gas flows through, therefore, the thermal flow sensor of the embodiment of the present application can overcome the defect that the existing thermal flow sensor cannot compensate the temperature of the reverse gas flow, and realize the bidirectional detection of the gas flow. Correspondingly, the downstream ambient resistor and the thermosensitive resistor will be heated each time the gas flows through, when the thermosensitive element cannot be heated or the temperature change does not meet the expected effect, it can be determined that the sensor has a fault, therefore, the thermal flow sensor of the embodiment of the present application can also perform self-detection and judgment through the temperature change of the two ambient resistors, and verify the reliability of the sensor.

[0042] In some example embodiments, the surface of the substrate 700 is further formed with electrode pads of the flow measuring unit and the compensation unit, for electrical connection to both ends of the resistance elements through the wire structure 800, and electrical conduction with the outside. Specifically, the electrode pads include a first electrode 1, a second electrode 2, a third electrode 3, a fourth electrode 4, a fifth electrode 5, a sixth electrode 6, a seventh electrode 7, an eighth electrode 8, a ninth electrode 9, and a tenth electrode 10, wherein the first electrode 1 and the second electrode 2 are respectively connected to both ends of the heating resistor 200, the third electrode 3 and the fourth electrode 4 are respectively connected to both ends of the upstream thermistor 100, the fifth electrode 5 and the sixth electrode 6 are respectively connected to both ends of the downstream thermistor 300, the seventh electrode 7 and the eighth electrode 8 are respectively connected to both ends of the upstream ambient resistor 400, and the ninth electrode 9 and the tenth electrode 10 are respectively connected to both ends of the downstream ambient resistor 500.

[0043] In some example embodiments, the substrate 700 can be a single-throw or double-throw semiconductor substrate, including but not limited to a silicon substrate, a germanium substrate, an SOI substrate, a GeOI substrate. In the embodiments of the present application, the substrate 710 is a double-throw monocrystalline silicon substrate.

[0044] In some example embodiments, the heating resistor 200 is a temperature-sensitive thermistor material, i.e., its resistance is positively correlated with temperature changes. Preferably, the heating resistor 200 uses one or a combination of nickel (Ni), platinum (Pt), gold (Au), aluminum (Al), copper (Au), and polysilicon. In the embodiments of the present application, the heating resistor 200 uses N+ type polysilicon. Further, in order to adapt to the stress changes caused by extreme temperatures, the surface of the heating resistor 200 can be attached with an adhesion layer, preferably, the adhesion layer uses titanium (Ti), chromium (Cr), nickel (Ni), titanium oxide (TiO2), or titanium-tungsten alloy.

[0045] In some example embodiments, the resistance values of the upstream thermistor 100 and the downstream thermistor 300 are greater than the resistance value of the heating resistor 200, for example, the resistance value of the thermistor is 2-100 times that of the heating resistor 200. The upstream thermistor 100 and the downstream thermistor 300 are temperature-sensitive thermistor materials, i.e., their resistance is positively correlated with temperature changes. Preferably, the upstream thermistor 100 and the downstream thermistor 300 use one or a combination of nickel (Ni), platinum (Pt), gold (Au), aluminum (Al), copper (Au), and polysilicon. In the embodiments of the present application, the upstream thermistor 100 and the downstream thermistor 300 use N+ type polysilicon. Further, in order to adapt to the stress changes caused by extreme temperatures, the surface of the upstream thermistor 100 and the downstream thermistor 300 can be attached with an adhesion layer, preferably, the adhesion layer uses titanium (Ti), chromium (Cr), nickel (Ni), titanium oxide (TiO2), or titanium-tungsten alloy.

[0046] In some example embodiments, the upstream thermal sensitive element 100 and the downstream thermal sensitive element 300 are thermocouples. Since the thermocouples are connected in series, the output voltage is N times of the output voltage of a single thermocouple, thereby improving the sensitivity of the sensor and the signal-to-noise ratio and the measurement accuracy of the thermal flow sensor. Further, the thermocouples include a plurality of groups of thermocouples connected in series, each group of thermocouples including an N+ type polysilicon thermocouple and a P+ type polysilicon thermocouple stacked in an up-down manner, an insulating layer being arranged between the N+ type polysilicon thermocouple and the P+ type polysilicon thermocouple, and the N+ type polysilicon thermocouple and the P+ type polysilicon thermocouple being connected by the wire structure 800, thereby further increasing the number of thermocouples under the same area and further improving the sensitivity of the sensor.

[0047] In some example embodiments, the upstream ambient resistance 400 and the downstream ambient resistance 500 are temperature sensitive thermistor materials, i.e., the resistance thereof is positively correlated with the temperature change. Preferably, the upstream ambient resistance 400 and the downstream ambient resistance 500 use a combination of one or more of nickel (Ni), platinum (Pt), gold (Au), aluminum (Al), copper (Au) and polysilicon. In the embodiments of the present application, the upstream ambient resistance 400 and the downstream ambient resistance 500 are platinum alloys deposited on the surface of the substrate 700 by magnetron sputtering, and the thickness of the upstream ambient resistance 400 and the downstream ambient resistance 500 is 0.1-10 um. Further, in order to adapt to the stress change caused by extreme temperature, the upstream ambient resistance 400 and the downstream ambient resistance 500 can be attached with an adhesion layer, and preferably, the adhesion layer uses titanium (Ti), chromium (Cr), nickel (Ni), titanium oxide (TiO2) or titanium tungsten alloy.

[0048] In some example embodiments, the resistance of the upstream ambient resistance 400 and the downstream ambient resistance 500 is equal.

[0049] In some example embodiments, in order to improve the sensitivity and the measurement accuracy of the sensor, the thermal flow sensor further includes a heat conduction layer 600 formed on the surface of the heating resistance 200 and in contact with the hot end of the upstream thermal sensitive element 100 and the downstream thermal sensitive element 300. In specific applications, the heat conduction layer 600 acts as a medium to replace air to conduct heat to the thermal sensitive element, on the one hand, the heat can be collected at the hot end of the sensitive element, thereby increasing the temperature of the hot end, on the other hand, the heat absorbed by the cold end of the sensitive element can be reduced, thereby increasing the temperature difference between the cold end and the hot end, improving the sensitivity and the measurement accuracy of the sensor. Preferably, the material of the heat conduction layer 600 is a high heat conduction efficiency material such as silicon nitride, aluminum oxide, aluminum nitride, magnesium oxide or boron nitride. In addition, the heat conduction layer 600 can also act as a protective layer of the heating resistance 200 to protect the heating resistance 200 from being damaged and contaminated, thereby improving the reliability and the structural stability of the device.

[0050] In some example embodiments, in order to ensure uniform heat distribution, the contact area of the heat-conducting layer 600 with the upstream thermal element 100 and the downstream thermal element 300 is equal.

[0051] In some example embodiments, in order to improve the sensitivity and measurement accuracy of the sensor, a heat insulation layer (not shown in the figure) is provided between the heat-conducting layer 600 and the substrate 700. The heat insulation layer can prevent heat transfer from the heating resistor 200 to the substrate 700 during the process of heating by the heating resistor 200, reduce heat loss, and improve the sensitivity and measurement accuracy of the sensor. Preferably, the heat insulation layer is made of insulating and heat-insulating materials such as silicon oxide.

[0052] In some example embodiments, in order to reduce heat loss, the back of the substrate 700 is provided with a cavity 730, which is located at the position of the heating resistor 200 on the substrate 700. The cavity 730 is used to reduce the heat transferred from the heating resistor 200 to the substrate 700, so that the temperature field center of the heating resistor 200 during heating is closer to the surface of the substrate 700, thereby reducing heat loss and improving the sensitivity and measurement accuracy of the sensor. In order to further reduce the heat transferred from the heating resistor 200 to the back of the substrate 700, a cavity 730 protective layer can also be provided on the back of the substrate 700 to enclose the cavity 730 on the back of the substrate 700, forming a vacuum structure, and at the same time, a gas or liquid with extremely low thermal conductivity can also be used to fill the cavity 730. Preferably, the cavity 730 protective layer is made of silicon (Si), quartz glass (SiO2), polyimide (Polyimide), or ceramic, and the thickness of the cavity 730 protective layer is 0.1-0.7mm.

[0053] In some example embodiments, in order to maintain the temperature difference between the cold and hot ends of the thermal elements, the hot end of the upstream thermal element 100 and the downstream thermal element 300 is located at the position of the cavity 730 on the substrate 700, and the cold end of the thermal element is located at the position corresponding to the surface of the substrate 700 and the non-cavity 730. In specific applications, the cavity 730 can reduce the heat transfer from the hot end to the substrate 700 and its back, thereby maintaining the temperature difference between the cold and hot ends, and improving the sensitivity and measurement accuracy of the sensor.

[0054] In some exemplary embodiments, the substrate 700 includes a substrate 710. A support layer 720 is provided on the surface of the substrate 710. The flow measurement unit and the compensation unit are located on the support layer 720. A cavity 730 is provided on the back surface of the substrate 710 to expose the support layer 720. In specific applications, the support layer 720 can serve as an etching stop layer for the substrate 710 during the formation of the cavity 730, and can also serve as the support layer 720 for the heating resistor 200 and the thermosensitive element. Specifically, the support layer 720 can be formed by stacking a silicon oxide layer 721 and a silicon nitride layer 722. The silicon oxide layer 721 has a low thermal conductivity, which can prevent heat from being transferred to the substrate 710 and its back surface. At the same time, since the thermal stresses of silicon oxide and silicon nitride are complementary in opposite directions, composite films with low stress can be prepared by selecting different thicknesses of silicon oxide and silicon nitride, so that the support layer 720 has good supporting force.

[0055] In some exemplary embodiments, through holes 210 are provided in the heating resistor 200 to form a parallel structure to reduce the resistance value of the heating resistor 200. In specific applications, when two resistors are connected in parallel, with the voltage remaining unchanged, the power of the heating resistor 200 can be increased, and the heat generation can be increased, which is beneficial to improving the measurement accuracy. Preferably, the through hole 210 can be one of a square hole, a circular hole, an oval hole, etc., and the heating resistor 200 is in a "return" shape.

[0056] In some exemplary embodiments, in order to prevent residues from affecting the detection accuracy, the compensation unit is also used to generate heat by being powered on to form a high temperature to remove water vapor and gas residues on the surface of the thermal flow sensor. In specific applications, it is necessary to keep the gas and the chip surface dry and clean to ensure the measurement accuracy. However, in actual applications, it is inevitable that a small amount of impurity gas or water vapor will enter the pipeline, resulting in adsorption on the chip surface and thus affecting the measurement accuracy. Therefore, after the detection is completed, a high level can be applied to the compensation unit through a selection switch or the like, so that the compensation unit generates heat to form a high temperature to remove the water vapor and gas residues on the surface of the thermal flow sensor.

[0057] In some exemplary embodiments, in order to make the heat distribution on the chip surface uniform, the upstream ambient resistor 400 and the downstream ambient resistor 500 are in a serpentine structure.

[0058] In some example embodiments, the thermal flow sensor further comprises a protective layer (not shown in the figure) arranged on the surfaces of the flow measurement unit, the compensation unit and the substrate 700, which can protect the elements from damage and improve the service life of the sensor. Further, the protective layer is a double-layer structure comprising an element protective layer 910 and a chip protective layer 920, the element protective layer 910 is formed on the surfaces of the heating resistor 200, the thermal elements and the heat-conducting layer 600 and the substrate 700, and the chip protective layer 920 is formed on the element protective layer 910. Specifically, the element protective layer 910 is used to protect the heating resistor 200, the upstream thermal element 100 and the downstream thermal element 300, and also serves as an insulating layer. The element protective layer 910 can be made of materials such as silicon carbide (SiC), silicon nitride (Si3N4), aluminum oxide (Al2O3), silicon dioxide (SiO2), Parylene or Cytop, and the thickness of the element protective layer 910 is 0.01-100 μm. The chip protective layer 920 is used to protect the entire sensor and improve the overall strength and mechanical properties of the sensor, which is also a key protective layer for improving the service life of the sensor. The chip protective layer 920 can be made of materials such as silicon carbide (SiC), aluminum oxide (Al2O3), silicon nitride (Si3N4), silicon dioxide (SiO2), Parylene or Cytop, and the thickness of the chip protective layer 920 is 0.01-100 μm. Since the above-mentioned materials with higher hardness, wear resistance and other mechanical properties are used to form a thin film structure as the protective layer, the internal elements can be effectively isolated from gases and liquids to improve the overall strength of the sensor by 50%, and the service life of the sensor can reach 6 years.

[0059] As shown in Figure 3 The application also provides a gas flow detection method, which is applied to the thermal flow sensor of the above-mentioned embodiments and comprises a flow detection step, which specifically comprises:

[0060] Step S10, determining the flow direction of the target gas flow;

[0061] Step S20, determining whether the temperatures of the thermal elements and the ambient resistor located downstream of the target gas flow are both increased according to the determined flow direction of the target gas flow.

[0062] Step S30, if yes, taking the temperature of the ambient resistor located upstream of the flowing gas as the ambient temperature to perform temperature compensation.

[0063] According to the above steps, when the gas flows from the upstream element to the downstream element of the thermal flow sensor, the gas flowing through carries away the heat of the upstream thermal element 100 and the heating resistor 200, and heats the downstream thermal element 300 and the downstream ambient resistor 500, at this time, the upstream ambient resistor 400 is not affected by the temperature, and the temperature of the upstream ambient resistor 400 can be used to determine the ambient temperature, and the detection result is temperature compensated; similarly, when the gas flows from the downstream element to the upstream element of the thermal flow sensor, the gas flowing through carries away the heat of the downstream thermal element 300 and the heating resistor 200, and heats the upstream thermal element 100 and the upstream ambient resistor 400, at this time, the temperature of the downstream ambient resistor 500 can be used to determine the ambient temperature, and the detection result is temperature compensated. As can be seen, when the thermal flow sensor of the embodiment of the present application is used for gas flow detection, the upstream ambient resistor is not affected by the change of the gas temperature each time the gas flows through, therefore, the thermal flow sensor of the embodiment of the present application can overcome the defect that the existing thermal flow sensor cannot perform temperature compensation for reverse airflow, and realize bidirectional detection of airflow. Correspondingly, the downstream ambient resistor and the thermal resistor are heated each time the gas flows through, when the thermal element cannot be heated or the temperature change does not meet the expected effect, it can be determined that the sensor has a fault, therefore, the thermal flow sensor of the embodiment of the present application can also perform self-detection and judgment through the temperature change of the two ambient resistors, and verify the reliability of the sensor.

[0064] In some exemplary embodiments, after the flow detection, the method further includes a cleaning step, which specifically includes:

[0065] In the compensation unit, the current is passed to heat the compensation unit to form high temperature, so as to remove the water vapor and gas residues on the surface of the thermal flow sensor.

[0066] As Figure 4 shown, the embodiment of the present application also provides an electronic device M00, which includes a processor M01, a memory M02, a program or instruction stored on the memory M02 and executable on the processor M01, the program or instruction is executed by the processor M01 to realize the processes of the above-mentioned method embodiments, and the same technical effects can be achieved, to avoid repetition, which will not be repeated here.

[0067] It should be noted that the electronic device in the embodiment of the present application includes the above-mentioned mobile electronic device and non-mobile electronic device.

[0068] As Figure 5As shown, in some exemplary embodiments, an electronic device x00 is provided, which includes, but is not limited to, a radio frequency unit x01, a network module x02, an audio output unit x03, an input unit x04, a sensor x05, a display unit x06, a user input unit x07, an interface unit x08, a memory x09, and a processor x10, etc.

[0069] Those skilled in the art can understand that the electronic device x00 can also include a power supply (such as a battery) for supplying power to each component, and the power supply can be logically connected to the processor x10 through a power management system, so as to realize the functions of managing charging, discharging, and power consumption management through the power management system. Figure 5 The electronic device structure shown in the figure does not constitute a limitation on the electronic device, and the electronic device can include more or fewer components than the figure, or combine certain components, or different component arrangements, which are not described here.

[0070] The embodiments of the present application also provide a storage medium, and the storage medium stores a program or instructions, which are executed by a processor to realize each process of the above-mentioned method embodiments and achieve the same technical effects. To avoid repetition, details are not described here.

[0071] The processor is a processor in the electronic device in the above-mentioned embodiments. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory (Read-Only Memory, ROM), a random access memory (Random Access Memory, RAM), a magnetic disk or an optical disk, etc.

[0072] The embodiments of the present application are described above in combination with the drawings, but the present application is not limited to the above-mentioned specific embodiments, and the above-mentioned specific embodiments are only illustrative, rather than limiting. Those skilled in the art can make many forms under the inspiration of the present application without departing from the scope of the present application and the protection scope of the claims, which all belong to the protection scope of the present application.

Claims

1. A gas flow detection method, applied to a thermal flow sensor, characterized in that, The thermal flow sensor includes: a flow measurement unit formed on the surface of a substrate, the flow measurement unit including an upstream thermistor, a heating resistor, and a downstream thermistor arranged sequentially; a compensation unit formed on the surface of the substrate, the compensation unit including an upstream ambient resistor located upstream of the flow measurement unit and a downstream ambient resistor located downstream of the flow measurement unit; the heating resistor is used to energize and heat the upstream thermistor and the downstream thermistor; the heating resistor is also used to generate heat through flowing gas to heat one of the upstream ambient resistor and the downstream ambient resistor; The method includes a flow detection step, which specifically includes: Determine the direction of the target airflow; Based on the determined direction of the target airflow, determine whether the temperature of the thermistor and the ambient resistance located downstream of the target airflow rises simultaneously; If so, the ambient temperature is taken as the temperature of the environmental resistance located upstream of the flowing gas, and temperature compensation is performed.

2. The method according to claim 1, characterized in that, The thermal flow sensor also includes: A thermally conductive layer is formed on the surface of the heating resistor and is in contact with the hot ends of the upstream and downstream thermistors.

3. The method according to claim 1, characterized in that, The back of the substrate has a cavity, which is located on the substrate at the position corresponding to the heating resistor.

4. The method according to claim 3, characterized in that, The hot ends of the upstream and downstream thermistors are located on the substrate at positions corresponding to the cavity.

5. The method according to claim 3, characterized in that, The substrate includes a substrate, a support layer is provided on the surface of the substrate, the flow measurement unit and the compensation unit are located on the support layer, and the cavity is provided on the back side of the substrate and exposes the support layer.

6. The method according to claim 1, characterized in that, The heating resistor has through holes to form a parallel structure, thereby reducing the resistance value of the heating resistor.

7. The method according to claim 1, characterized in that, The compensation unit is also used to generate heat when energized to remove water vapor and gas residue from the surface of the thermal flow sensor.

8. The method according to claim 7, characterized in that, The upstream environmental resistance and the downstream environmental resistance have a serpentine structure.

9. The method according to claim 7, characterized in that, Following flow detection, the method further includes a cleaning step, which specifically includes: An electric current is passed through the compensation unit to generate heat and high temperature, thereby removing water vapor and gas residue from the surface of the thermal flow sensor.

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