Airflow detection circuit and device based on piezoelectric film and electronic atomizer

Abstract

The application discloses a kind of based on piezoelectric film air flow detection circuit, air flow detection device and electronic atomizer, by adopting piezoelectric film as sensing element, combining integral circuit design, transient electrical signal is converted into stable detection voltage output, so that the deformation size of piezoelectric film can be accurately judged, and then the function of accurately detecting air flow is realized.The problems of weak anti-interference ability, poor signal stability and other problems existing in traditional air flow detection technology can be effectively solved.

Description

Technical Field

[0001] This application relates to the field of sensing and detection technology, and in particular to airflow detection circuits, airflow detection devices, and electronic atomizers based on piezoelectric thin films. Background Technology

[0002] Current airflow detection technologies mainly employ the following solutions: capacitive membrane sensors, which detect airflow through changes in capacitance; these are low-cost but susceptible to grease contamination, leading to false detections; resistive membrane sensors, based on the principle of resistance changes, have insufficient sensitivity and are difficult to detect minute airflows; and MEMS sensors, which are prone to pore blockage and have low reliability over long-term use. All of these solutions suffer from weak anti-interference capabilities and poor signal stability. Utility Model Content

[0003] This application proposes an airflow detection circuit, airflow detection device, and electronic atomizer based on a piezoelectric thin film. It uses a piezoelectric thin film as the sensing element and combines it with an integrating circuit design to convert transient electrical signals into a stable voltage output, effectively overcoming the shortcomings of existing technologies. The specific technical solution is as follows:

[0004] An airflow detection circuit based on a piezoelectric thin film includes: a piezoelectric thin film for deforming under the action of airflow and generating an electrical signal; a DC blocking capacitor connected to the piezoelectric thin film, wherein the DC blocking capacitor filters out the DC component in the electrical signal generated by the piezoelectric thin film; and an integrating circuit connected to the DC blocking capacitor, wherein the integrating circuit receives the signal output by the DC blocking capacitor and converts it into a detection voltage output.

[0005] Furthermore, the integrating circuit includes an operational amplifier, an integrating resistor, and an integrating capacitor. The inverting input terminal of the operational amplifier is connected to the DC blocking capacitor through the integrating resistor, the non-inverting input terminal of the operational amplifier is connected to a reference voltage, and the two ends of the integrating capacitor are respectively connected to the inverting input terminal and the output terminal of the operational amplifier.

[0006] Furthermore, the airflow detection circuit also includes an offset resistor, the two ends of which are respectively connected to the inverting input terminal and the output terminal of the operational amplifier.

[0007] Furthermore, the airflow detection circuit also includes a discharge switch, the two ends of which are respectively connected to the two ends of the integrating capacitor.

[0008] An airflow detection device includes the above-mentioned airflow detection circuit based on a piezoelectric film. The airflow detection device has an air hole, the piezoelectric film covers the air hole, one end of the piezoelectric film is fixed to the edge of the air hole, and the other end opens the air hole when airflow passes through it and covers the air hole when no airflow passes through it.

[0009] Furthermore, the airflow detection device also includes a controller, which is connected to the output of the operational amplifier.

[0010] Furthermore, the controller is also connected to the non-inverting input of the operational amplifier.

[0011] Furthermore, the controller is also connected to a discharge switch to control the on / off state of the discharge switch.

[0012] An electronic atomizer includes the aforementioned piezoelectric film-based airflow detection circuit. The electronic atomizer includes a cavity with an air outlet, an air inlet, and a detection port. The piezoelectric film covers the detection port, and the edge of the piezoelectric film is fixed to the edge of the detection port. When gas flows out of the cavity from the air outlet, a negative pressure is formed in the cavity, causing the piezoelectric film to deform.

[0013] Furthermore, the electronic atomizer also includes a controller, which is connected to the non-inverting input and output of the operational amplifier, and is also connected to a discharge switch to control the on / off state of the discharge switch.

[0014] The piezoelectric thin film-based airflow detection circuit, airflow detection device, and electronic atomizer described in this application can convert the electrical signal generated by the piezoelectric thin film into a stable voltage output, thereby accurately determining the deformation of the piezoelectric thin film and thus achieving the function of accurately detecting airflow. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of an airflow detection circuit according to an embodiment of this application.

[0016] Figure 2 This is a schematic diagram of the airflow detection device according to an embodiment of this application.

[0017] Figure 3 This is a schematic diagram of an electronic atomizer structure according to an embodiment of this application. Detailed Implementation

[0018] The embodiments of this application will now be described in detail with reference to the accompanying drawings. These drawings, as part of the disclosure of this application, are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of this application.

[0019] like Figure 1The airflow detection circuit shown includes a piezoelectric thin film T1, a DC blocking capacitor C2, and an integrating circuit. The piezoelectric thin film is a sensor that converts mechanical energy into electrical energy using the piezoelectric effect. When the piezoelectric thin film deforms under force, an electrical signal is generated between the upper and lower electrode surfaces, and the signal magnitude changes proportionally to the deformation. While most piezoelectric materials are pressure-sensitive, for a piezoelectric thin film, applying a small force longitudinally generates a large stress transversely, while applying the same force over a large area of ​​the film produces a much smaller stress. Therefore, piezoelectric thin films are highly sensitive to dynamic stress. The piezoelectric thin film T1 in the airflow detection circuit is used to deform under the action of airflow and generate an electrical signal. The DC blocking capacitor C2 is connected to the piezoelectric thin film T1 and filters out the DC component from the electrical signal generated by the piezoelectric thin film T1. The integrating circuit is connected to the DC blocking capacitor C2, and receives the signal output from the DC blocking capacitor C2 and converts it into a detection voltage output.

[0020] The integrating circuit includes an operational amplifier U1, an integrating resistor R2, and an integrating capacitor C1. The inverting input of the operational amplifier U1 is connected to the DC blocking capacitor C2 through the integrating resistor R2, the non-inverting input of the operational amplifier U1 is connected to the reference voltage Vref, and the two ends of the integrating capacitor C1 are connected to the inverting input and the output Vout of the operational amplifier U1, respectively.

[0021] When the piezoelectric film T1 deforms under stress, it generates a certain amount of charge. This charge forms an electrical signal that is transmitted to the integrating circuit through the DC blocking capacitor C2. After processing the signal, the integrating circuit generates a stable output voltage, Vout, at its output terminal. This voltage is the detection voltage output by the airflow detection circuit. As long as the deformation continues, the charge remains constant, generally considered stable within a ten-second timeframe, thus ensuring a consistent detection voltage that reflects the deformation of the piezoelectric film T1. When the deformation of the piezoelectric film T1 recovers, an opposite charge is generated and coupled to the integrating capacitor C1 through the DC blocking capacitor C2, thus canceling each other out and restoring the output detection voltage to its initial value.

[0022] This airflow detection circuit converts the charge change of the piezoelectric film T1 into a stable voltage output, allowing the determination of the magnitude of the deformation of the piezoelectric film T1 and thus the detection of the airflow. For example, in an aerosol device, the piezoelectric film T1 continuously deforms during inhalation, converting the charge generated by this deformation into a fixed output voltage, thus detecting the airflow. Without the processing of the airflow detection circuit, only a transient electrical signal would be detected, making it difficult for the controller to determine the current airflow state.

[0023] In one embodiment, the airflow detection circuit further includes an offset resistor R1, the two ends of which are connected to the inverting input and output Vout of the operational amplifier U1, respectively. The offset resistor R1 is a large resistor, which can prevent the operational amplifier U1 from becoming offset.

[0024] In one embodiment, the airflow detection circuit further includes a discharge switch K1, the two ends of which are respectively connected to the two ends of the integrating capacitor C1, which can realize the initial discharge of the airflow detection circuit.

[0025] like Figure 2 As shown, the airflow detection device includes the aforementioned airflow detection circuit based on the piezoelectric film T1. The device comprises a rectangular cavity structure with an air hole Q1 at the bottom. The piezoelectric film T1 covers the air hole Q1, with one end fixed to the edge of the air hole Q1 and the other end opening the air hole Q1 when airflow passes through it, and covering it when no airflow passes through it. An opening is also provided at the top of the cavity, with the arrow in the figure indicating the direction of airflow. When airflow flows upwards out of the cavity from the opening, a negative pressure is created inside the cavity. The external pressure causes the unfixed end of the piezoelectric film T1 to roll into the cavity, thereby opening the air hole Q1. Airflow enters the cavity through the air hole Q1 and flows out from the opening.

[0026] The airflow detection device also includes a controller, which can be a control chip such as an MCU, DSP, or FPGA capable of data or signal processing. The controller is connected to the non-inverting input and output Vout of the operational amplifier U1. The controller is also connected to a discharge switch K1 to control the on / off state of the discharge switch K1.

[0027] When the airflow detection device starts working, the controller sends a control signal to close the discharge switch K1 for initial discharge. After the discharge is complete, the airflow detection device begins real-time monitoring. When the piezoelectric film T1 deforms, the generated electrical signal is transmitted to the integrating circuit through the DC blocking capacitor C2. After processing the electrical signal, the integrating circuit generates a stable detection voltage at its output terminal Vout. Upon receiving this detection voltage, the controller determines that the piezoelectric film T1 has deformed, indicating that airflow has entered the cavity from the air hole Q1, thus realizing the airflow detection function.

[0028] like Figure 3As shown, the electronic atomizer includes the aforementioned airflow detection circuit based on the piezoelectric film T1. The electronic atomizer includes a rectangular cavity with an air outlet S2, an air inlet S1, and a detection port J1. The piezoelectric film T1 covers the detection port J1, and the edge of the piezoelectric film T1 is fixed to the edge of the detection port J1. When gas flows out of the cavity from the air outlet S2, a negative pressure is formed in the cavity, causing the center of the piezoelectric film T1 to deform inward.

[0029] The electronic atomizer also includes a controller, which is connected to the non-inverting input and output Vout of the operational amplifier U1, respectively. The controller is also connected to the discharge switch K1 to control the on / off state of the discharge switch K1.

[0030] When the electronic atomizer is powered on and begins operation, the controller sends a control signal to close the discharge switch K1 for initial discharge. After the discharge, the electronic atomizer begins real-time monitoring. When the piezoelectric film T1 deforms, the generated electrical signal is transmitted to the integrating circuit through the DC blocking capacitor C2. After processing the electrical signal, the integrating circuit generates a stable detection voltage at its output terminal Vout. Upon receiving this detection voltage, the controller determines that the piezoelectric film T1 has deformed, indicating that airflow is flowing into the cavity from the air inlet S1 and out from the air outlet S2. At this time, the controller immediately controls the heating wire or atomizing plate and other components to start working, atomizing the liquid. The atomized gas then flows out of the air outlet S2 along with the airflow, thus realizing the atomization function of the electronic device.

[0031] The above embodiments are only for illustrating the technical concept and features of this application, and are intended to enable those skilled in the art to understand the content of this application and implement it accordingly. They should not be used to limit the scope of protection of this application. All equivalent transformations or modifications made in accordance with the spirit and essence of this application should be included within the scope of protection of this application.

Claims

1. An airflow detection circuit based on a piezoelectric thin film, characterized in that, include: Piezoelectric films are used to deform under the action of airflow and generate electrical signals; A DC blocking capacitor is connected to the piezoelectric film, and the DC blocking capacitor filters out the DC component in the electrical signal generated by the piezoelectric film. An integrating circuit is connected to a DC blocking capacitor. The integrating circuit receives the signal output by the DC blocking capacitor and converts it into a detection voltage output.

2. The airflow detection circuit according to claim 1, characterized in that: The integrating circuit includes an operational amplifier, an integrating resistor, and an integrating capacitor. The inverting input of the operational amplifier is connected to a DC blocking capacitor through the integrating resistor, the non-inverting input of the operational amplifier is connected to a reference voltage, and the two ends of the integrating capacitor are connected to the inverting input and the output of the operational amplifier, respectively.

3. The airflow detection circuit according to claim 1 or 2, characterized in that: The airflow detection circuit also includes an offset resistor, the two ends of which are connected to the inverting input and output of the operational amplifier, respectively.

4. The airflow detection circuit according to claim 3, characterized in that: The airflow detection circuit also includes a discharge switch, the two ends of which are respectively connected to the two ends of the integrating capacitor.

5. An airflow detection device, comprising the piezoelectric thin film-based airflow detection circuit as described in any one of claims 1 to 4, characterized in that: The airflow detection device has an air hole, a piezoelectric film covers the air hole, one end of the piezoelectric film is fixed to the edge of the air hole, and the other end opens the air hole when airflow passes through it and covers the air hole when no airflow passes through it.

6. The airflow detection device according to claim 5, characterized in that: The airflow detection device also includes a controller, which is connected to the output of the operational amplifier.

7. The airflow detection device according to claim 6, characterized in that: The controller is also connected to the non-inverting input of the operational amplifier.

8. The airflow detection device according to claim 6, characterized in that: The controller is also connected to a discharge switch to control the on / off state of the discharge switch.

9. An electronic atomizer, comprising the piezoelectric thin film-based airflow detection circuit as described in any one of claims 1 to 4, characterized in that: The electronic atomizer includes a cavity with an air outlet, an air inlet, and a detection port. A piezoelectric film covers the detection port, and the edge of the piezoelectric film is fixed to the edge of the detection port. When gas flows out of the cavity from the air outlet, a negative pressure is formed in the cavity, causing the piezoelectric film to deform.

10. The electronic atomizer according to claim 9, characterized in that: The electronic atomizer also includes a controller, which is connected to the non-inverting input and output of the operational amplifier, and is also connected to a discharge switch to control the on / off state of the discharge switch.

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