A distance compensation type resonant electrostatic sensor and a detection method

Abstract

The application provides a distance compensation type resonant electrostatic sensor and a detection method, which comprises a sensitive structure and a circuit board with a signal processing part. The sensitive structure comprises a first vibrating beam and a second vibrating beam. The circuit board is provided with at least a first sensing electrode and a second sensing electrode in different planes and between the first vibrating beam and the second vibrating beam. The first vibrating beam and the second vibrating beam periodically vibrate to shield the first sensing electrode and the second sensing electrode, so as to generate a first current signal and a second current signal with a signal difference. The signal processing part obtains a first sensing charge value, a second sensing charge value and an installation distance coefficient according to the first current signal and the second current signal respectively, and obtains an electrostatic voltage value according to the first sensing charge value and the installation distance coefficient or the second sensing charge value and the installation distance coefficient. The application can obtain the electrostatic voltage value and realize distance compensation without setting a distance detection module.

Description

TECHNICAL FIELD

[0001] The present application relates to an electrostatic sensor, in particular to a distance compensation type resonant electrostatic sensor and a detection method. BACKGROUND

[0002] An electrostatic sensor is a device for measuring electric field intensity, which is widely used in national defense, aerospace, weather detection, power, scientific research and industrial production, and plays a very important role. Especially in the field of industrial production, using an electrostatic sensor to monitor the potential distribution and electric field distribution in the industrial environment helps us to take effective measures to prevent accidents in time.

[0003] At present, the existing resonant electric field type electrostatic sensor can measure the voltage of a charged object without contact. Its main principle is to generate an induced current proportional to the size of the electric field by modulating the induced charge on the sensing electrode in the measured electric field environment through a periodic vibrating structure, to detect the measured electric field, and then calculate the surface electrostatic voltage value of the measured object through the relationship between the measured electric field and the installation distance. Since it uses a non-contact measurement method, it does not require the material of the charged object, and is commonly used in manufacturing sites.

[0004] However, if the installation distance is different from the calibration distance when the non-contact electrostatic sensor is installed, it will bring a larger measurement error. The main reason is that when the distance between the non-contact electrostatic sensor and the measured object changes, the number of electric field lines transmitted to the electrostatic sensor will also change. Therefore, when the installation distance is greater than the reference distance at the time of calibration, the measurement value will be smaller, and when it is smaller than the reference distance, the measurement value will be larger.

[0005] Due to the complexity of the industrial production environment, such as machine vibration, installation error, uneven product height, narrow space of production line, and difficulty in determining the distance of the electrostatic tester during manual inspection, etc., the electric field type electrostatic detection sensor often has a large measurement error. At this time, distance compensation is needed to avoid large measurement errors.

[0006] However, the existing distance compensation method mainly sets an additional distance detection module (such as a dial switch, an ultrasonic sensor, etc.) in the resonant electrostatic sensor. This method increases the volume and processing cost of the electrostatic sensor, making it impossible to apply the electrostatic sensor to a narrow space. At the same time, due to the difference in measurement principle between the distance detection module and the electrostatic sensor, it can only measure the measured object that meets the detection mechanism of both sensors (such as the material and color of the measured object), which limits the application environment and measured object of the sensor.

[0007] Therefore, how to provide a resonant electrostatic sensor, so that it can realize distance compensation without additional distance detection module, is a problem to be solved at present. SUMMARY

[0008] In view of the above problems, the present application provides a distance compensation type resonant electrostatic sensor and a detection method, which can obtain an electrostatic voltage value, thereby realizing distance compensation without setting a distance detection module.

[0009] To achieve the above object, in a first aspect, the present application provides a distance compensation type resonant electrostatic sensor, comprising a sensitive structure and a circuit board with a signal processing part connected thereto, the sensitive structure comprising a first vibrating beam, a second vibrating beam, a driving electrode, a feedback electrode and an anchor point, at least a first sensing electrode and a second sensing electrode being provided on the circuit board and located between the first vibrating beam and the second vibrating beam in different planes, the first vibrating beam and the second vibrating beam periodically vibrating to shield the first sensing electrode and the second sensing electrode, so as to generate a first current signal and a second current signal with a signal difference value;

[0010] The signal processing part obtains a first sensing charge value, a second sensing charge value and an installation distance coefficient according to the first current signal and the second current signal respectively, and obtains an electrostatic voltage value according to the first sensing charge value and the installation distance coefficient, or the second sensing charge value and the installation distance coefficient.

[0011] In one embodiment, the first sensing electrode and the second sensing electrode have a height difference value, and the height difference value has a correlation with the signal difference value.

[0012] In one embodiment, a first shielding structure connected to the first vibrating beam and periodically vibrating with the first vibrating beam is provided on the first vibrating beam, and the first shielding structure is located directly above the first sensing electrode and the second sensing electrode.

[0013] A second shielding structure connected to the second vibrating beam and periodically vibrating with the second vibrating beam is provided on the second vibrating beam, and the second shielding structure is located directly above the first sensing electrode and the second sensing electrode.

[0014] In one embodiment, the first shielding structure and the second shielding structure both cover a part of the top end face of the first sensing electrode and the second sensing electrode, and a reserved interval is formed between the first shielding structure and the second shielding structure.

[0015] In the non-vibration state, the top end surface of the first sensing electrode forms a shielding area a and a non-shielding area a, and the top end surface of the second sensing electrode forms a shielding area b and a non-shielding area b.

[0016] In one of the embodiments, the first shielding structure is a shielding electrode a, and the second shielding structure is a shielding electrode b, wherein the shielding electrode a corresponds to the shielding electrode b and is in the same plane, and the reserved interval a is formed between the shielding electrode a and the shielding electrode b.

[0017] In one of the embodiments, the first shielding structure includes at least a first shielding electrode and a third shielding electrode arranged in front and back and in the same plane or different planes, and the second shielding structure includes at least a second shielding electrode and a fourth shielding electrode arranged in front and back and in the same plane or different planes, wherein the first shielding electrode corresponds to the second shielding electrode and is in the same plane, and the reserved interval a is formed between the first shielding electrode and the second shielding electrode, and the third shielding electrode corresponds to the fourth shielding electrode and is in the same plane, and the reserved interval b is formed between the third shielding electrode and the fourth shielding electrode.

[0018] In one of the embodiments, the signal processing part includes a self-oscillation circuit, a signal processing module and a calculation module, wherein:

[0019] The self-oscillation circuit is connected with the feedback electrode and the driving electrode respectively, the self-oscillation circuit receives the feedback signal input by the feedback electrode, and inputs the driving signal to the driving electrode;

[0020] The signal processing module converts the first current signal and the second current signal into a first electric field value and a second electric field value respectively;

[0021] The calculation module derives a first induced charge value, a second induced charge value and an installation distance coefficient according to the first electric field value and the second electric field value, and derives an electrostatic voltage value according to the first induced charge value and the installation distance coefficient, or the second induced charge value and the installation distance coefficient.

[0022] In one of the embodiments, the signal processing module includes a first IV conversion circuit, a second IV conversion circuit, a modulation circuit and an ADC sampling circuit, wherein:

[0023] The first IV conversion circuit converts the first current signal into a first voltage signal;

[0024] The second IV conversion circuit converts the second current signal into a second voltage signal;

[0025] The modulation circuit modulates the first voltage signal and the second voltage signal to form a first electric field analog value and a second electric field analog value.

[0026] The ADC sampling circuit converts the first electric field analog value and the second electric field analog value into the first electric field value and the second electric field value, respectively.

[0027] In one of the embodiments, the solving module includes a first calculation unit, a second calculation unit, and a third calculation unit, wherein:

[0028] The first calculation unit is configured to derive a first induced charge amount value and a second induced charge amount value from the first electric field value and the second electric field value, and derive a proportionality coefficient of the induced charge amount value from the first induced charge amount value and the second induced charge amount value.

[0029] The second calculation unit is configured to derive an installation distance value from the proportionality coefficient of the induced charge amount value and the height difference value, and determine an installation distance coefficient from the installation distance value.

[0030] The third calculation unit is configured to derive an electrostatic voltage value from the first induced charge amount value and the installation distance coefficient, or the second induced charge amount value and the installation distance coefficient.

[0031] In a second aspect, the present application further provides a detection method applied to the above-mentioned distance compensation type resonant electrostatic sensor, including the following steps:

[0032] In the current electric field environment, the first sensing electrode and the second sensing electrode on different planes periodically vibrate to generate a first current signal and a second current signal with a signal difference value.

[0033] The first current signal and the second current signal are converted into a first electric field value and a second electric field value, respectively.

[0034] A first induced charge amount value, a second induced charge amount value, and an installation distance coefficient are derived from the first electric field value and the second electric field value, respectively, and an electrostatic voltage value is derived from the first induced charge amount value and the installation distance coefficient, or the second induced charge amount value and the installation distance coefficient.

[0035] In one of the embodiments, the deriving of the first induced charge amount value, the second induced charge amount value, and the installation distance coefficient from the first electric field value and the second electric field value, and the deriving of the electrostatic voltage value from the first induced charge amount value and the installation distance coefficient, or the second induced charge amount value and the installation distance coefficient, includes:

[0036] respectively, to obtain a first induced charge quantity value and a second induced charge quantity value;

[0037] The first induced charge quantity value and the second induced charge quantity value are calculated to obtain a proportion coefficient of the induced charge quantity value;

[0038] A mounting distance value of the current electrostatic sensor is determined according to the proportion coefficient of the induced charge quantity value;

[0039] A mounting distance coefficient is determined according to the mounting distance value;

[0040] The first induced charge quantity value and the mounting distance coefficient, or the second induced charge quantity value and the mounting distance coefficient are calculated to obtain an electrostatic voltage value.

[0041] Compared with the prior art, the present application has one of the following advantages:

[0042] Since the first sensing electrode and the second sensing electrode are in different planes, the first current signal and the second current signal with a signal difference can be sensed, and the first induced charge quantity value and the second induced charge quantity value with a signal difference can be obtained, and the electrostatic voltage value can be obtained through the first induced charge quantity value and the mounting distance coefficient, or the second induced charge quantity value and the mounting distance coefficient, so that distance compensation is realized without the need to set a distance detection module, the volume of the electrostatic sensor is reduced, and the processing cost is reduced; at the same time, the application environment and the measured object of the sensor are limited due to the difference in measurement principle between the distance detection module and the electrostatic sensor (such as the specific requirement of the optical distance detection module for the color of the measured object, etc.);

[0043] The mounting distance value and the mounting distance coefficient can be obtained through the proportion coefficient of the induced charge quantity value, and the mounting position of the electrostatic sensor can be accurately obtained, so that the electrostatic voltage value of the current environment or the measured object can be detected;

[0044] By increasing the first shielding structure and the second shielding structure, the sensitivity of the first sensing electrode and the second sensing electrode can be increased when the first sensing electrode and the second sensing electrode sense the first current signal and the second current signal, and the accuracy of the first current signal and the second current signal can be improved;

[0045] Since the first shielding structure and the second shielding structure form a reserved interval therebetween, when the first vibrating beam and the second vibrating beam perform periodic vibration, the first shielding structure and the second shielding structure are prevented from colliding, and the working state of the electrostatic sensor is not affected. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 is a perspective view of a first embodiment of the distance compensation type resonant electrostatic sensor in the present application;

[0047] Figure 2 Fig. 3 is a perspective view of a second embodiment of the distance-compensated resonant electrostatic sensor according to the present application;

[0048] Figure 3 Fig. 4 is a perspective view of a third embodiment of the distance-compensated resonant electrostatic sensor according to the present application;

[0049] Figure 4 Fig. 5 is a perspective view of the third embodiment of the distance-compensated resonant electrostatic sensor according to the present application; Figure 3 Fig. 6 is a perspective view of the third embodiment of the distance-compensated resonant electrostatic sensor according to the present application;

[0050] Figure 5 Fig. 7 is a top view of the third embodiment of the distance-compensated resonant electrostatic sensor according to the present application; Figure 3 Fig. 8 is a sectional view of the third embodiment of the distance-compensated resonant electrostatic sensor according to the present application;

[0051] Figure 6 Fig. 9 is a sectional view of the third embodiment of the distance-compensated resonant electrostatic sensor according to the present application; Figure 5 Fig. 10 is a block diagram of the third embodiment of the distance-compensated resonant electrostatic sensor according to the present application;

[0052] Figure 7 Fig. 11 is a block diagram of the third embodiment of the distance-compensated resonant electrostatic sensor according to the present application; Figures 1 to 3 Fig. 12 is a flowchart of the detection method according to the present application;

[0053] Figure 8 Fig. 13 is a flowchart of the detection method according to the present application;

[0054] Figure 9 Fig. 14 is a flowchart of the detection method according to the present application.

[0055] The main reference signs and their contents are as follows:

[0056] 1 - first sensing electrode; 2 - second sensing electrode; 3 - circuit board; 4 - first vibrating beam; 5 - first shield electrode; 6 - third shield electrode; 7 - driving electrode; 8 - second vibrating beam; 9 - second shield electrode; 10 - fourth shield electrode; 11 - feedback electrode; 12 - anchor point; 13 - support a; 14 - support b; 15 - shield electrode a; 16 - shield electrode b. DETAILED DESCRIPTION

[0057] In order to make the objects, technical solutions, and advantages of the present application clearer, the technical solutions of the present application will be described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0058] In the description of the present application, it should be understood that the terms "upper", "lower", "top surface", "bottom surface", "interior" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there can be a component disposed therebetween. In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0059] Embodiment one

[0060] As Figure 1 With Figure 7 As shown in the embodiment, a distance compensation type resonant electrostatic sensor is provided, which includes a sensitive structure and a circuit board 3 with a signal processing part connected thereto, the sensitive structure is used to sense the charge in the current electric field environment to form a current signal, and the signal processing part processes the current signal sensed by the sensitive structure to obtain an electrostatic voltage value.

[0061] The sensitive structure is arranged on the circuit board 3, which includes a first sensing electrode 1, a second sensing electrode 2, a first vibration beam 4, a second vibration beam 8, a driving electrode 7, a feedback electrode 11 and an anchor point 12.

[0062] Specifically, the first sensing electrode 1 and the second sensing electrode 2 are both a suspended metal plate, arranged in front and back, on the same axis, and both are fixed on the circuit board 3. Among them, the height of the first sensing electrode 1 and the height of the second sensing electrode 2 are different, so that the top end surface of the first sensing electrode 1 and the top end surface of the second sensing electrode 2 are in different planes.

[0063] Further, the height of the first sensing electrode 1 is greater than the height of the second sensing electrode 2, and the top end surface of the first sensing electrode 1 and the top end surface of the second sensing electrode 2 have a height difference (i.e. d0).

[0064] Further, the height difference (i.e. d0) is a known value measured when the first sensing electrode 1 and the second sensing electrode 2 are processed or when the first sensing electrode 1 and the second sensing electrode 2 are installed.

[0065] Specifically, the anchor point 12 is located at the top of the first vibrating beam 4 and the second vibrating beam 8, and is connected with the first vibrating beam 4 and the second vibrating beam 8 respectively to form a vibrating structure. The driving electrode 7 is arranged on the inner side wall surface of the first vibrating beam 4, towards the position of the second vibrating beam 8, for generating mechanical stress or strain when an electric signal is applied to drive the first vibrating beam 4 to vibrate. The feedback electrode 11 is arranged on the inner side wall surface of the second vibrating beam 8, towards the position of the first vibrating beam 4, and corresponds to the position of the driving electrode 7, for generating an electric signal when mechanical stress or strain is generated to reflect the vibration parameters of the vibrating structure.

[0066] The first vibrating beam 4 is fixed on the circuit board 3 by the support a13, and the second vibrating beam 8 is fixed on the circuit board 3 by the support b14. The first vibrating beam 4 and the second vibrating beam 8 correspond in position and are arranged in a spaced manner to form a spacing region, so that the first sensing electrode 1 and the second sensing electrode 2 are located in the region between the first vibrating beam 4 and the second vibrating beam 8. Among them, the first sensing electrode 1 and the second sensing electrode 2 are both close to the first end of the first vibrating beam 4 and the first end of the second vibrating beam 8.

[0067] Specifically, when the first vibrating beam 4 and the second vibrating beam 8 vibrate periodically to shield the first sensing electrode 1 and the second sensing electrode 2, the first current signal and the second current signal with a signal difference value are generated. Among them, the height difference value (i.e. d0) and the signal difference value have a correlation.

[0068] Further, the height difference value (i.e. d0) is proportional to the signal difference value (i.e. the greater the height difference value, the greater the signal difference value, the smaller the height difference value, the smaller the signal difference value).

[0069] Specifically, the signal processing part includes a self-oscillation circuit, a signal processing module and a solving module, wherein:

[0070] The self-oscillation circuit is connected with the feedback electrode 11 and the driving electrode 7 respectively. The self-oscillation circuit receives the feedback signal input by the feedback electrode 11 and inputs the driving signal to the driving electrode 7;

[0071] The signal processing module converts the first current signal and the second current signal into the first electric field value and the second electric field value respectively;

[0072] The solving module derives the first induced charge value, the second induced charge value and the installation distance coefficient according to the first electric field value and the second electric field value, and derives the electrostatic voltage value of the current electric field environment or the electrostatic voltage value of the measured object according to the first induced charge value and the installation distance coefficient, or the second induced charge value and the installation distance coefficient.

[0073] Further, the first sensing electrode 1 and the second sensing electrode 2 sense the electric charges in the current electric field environment to generate current signals, which are conducted to the first vibrating beam 4 and the second vibrating beam 8 through the anchor point 12; the feedback stress generated by the second vibrating beam 8 generates a feedback signal through the feedback electrode 11 and is transmitted to the self-oscillation circuit; the self-oscillation circuit generates a driving signal according to the received feedback signal and transmits it to the driving electrode 7; the driving electrode 7 generates a driving stress according to the received driving signal, so that the first vibrating beam 4 vibrates, thereby realizing periodic vibration shielding between the first vibrating beam 4 and the first sensing electrode 1, the second sensing electrode 2, and the second vibrating beam 8 and the first sensing electrode 1, the second sensing electrode 2, to generate the first current signal and the second current signal with a signal difference.

[0074] Further, the signal processing module includes a first IV conversion circuit, a second IV conversion circuit, a modulation circuit, and an ADC sampling circuit, wherein:

[0075] The first IV conversion circuit converts the first current signal into a first voltage signal;

[0076] The second IV conversion circuit converts the second current signal into a second voltage signal;

[0077] The modulation circuit modulates the first voltage signal and the second voltage signal to form a first electric field analog value and a second electric field analog value;

[0078] The ADC sampling circuit converts the first electric field analog value and the second electric field analog value into a digitized first electric field value and a digitized second electric field value, respectively.

[0079] Further, the calculation module includes a first calculation unit, a second calculation unit, and a third calculation unit, wherein:

[0080] The first calculation unit is configured to derive a first sensing charge value and a second sensing charge value according to the first electric field value and the second electric field value, and derive a proportional coefficient (i.e., k0) of the sensing charge value according to the first sensing charge value and the second sensing charge value;

[0081] The second calculation unit is configured to derive an installation distance value (i.e., d A ) according to the proportional coefficient (i.e., k0) of the sensing charge value and a height difference value (i.e., d A ), and determine an installation distance coefficient (i.e., k A ) according to the installation distance value (i.e., d A );

[0082] The third calculation unit is configured to derive a first sensing charge value (i.e., Q A ) and an installation distance coefficient (i.e., k B) and the installation distance coefficient (i.e., k A ) to obtain the electrostatic voltage value of the current electric field environment or the measured object.

[0083] Further, in the first calculation unit, after obtaining the first induced charge value and the second induced charge value, a proportional coefficient of the induced charge value is obtained by using the following formula:

[0084]

[0085] wherein k0 is the proportional coefficient of the induced charge value, Q A is the first induced charge value, and Q B is the second induced charge value.

[0086] Further, in the second calculation unit, according to the proportional coefficient of the induced charge value (i.e., k0) and the height difference value (i.e., d0), and by using the following formula, the installation distance value (i.e., d A ) is obtained:

[0087]

[0088] wherein k0 is the proportional coefficient of the induced charge value, d A is the proportional coefficient of the induced charge value, and d0 is the height difference value.

[0089] In the above formula, k0 is obtained after being calculated by the first calculation unit, and d0 is a known value, thus the installation distance value d A can be obtained.

[0090] After obtaining the installation distance value (i.e., d A ) corresponding thereto, according to the installation distance value (i.e., d A ), the installation distance coefficient (i.e., k A ) corresponding thereto is searched and obtained.

[0091] Further, in the third calculation unit, the electrostatic voltage value of the current electric field environment or the measured object is obtained by using the following formula:

[0092] U=k A x Q A ,

[0093] wherein U is the electrostatic voltage value, k A is the installation distance coefficient, and Q A is the first induced charge value.

[0094] Alternatively, the electrostatic voltage value of the current electric field environment or the measured object is obtained by using the following formula:

[0095] U=k AxQ B ,

[0096] wherein, U is the electrostatic voltage value, k A is the installation distance coefficient, Q B is the second induced charge value.

[0097] In addition, in another possible embodiment, the second calculation unit in the calculation module can also be replaced by a matching module, wherein the matching unit is used to determine the installation distance value (i.e., d A ) according to the proportional coefficient of the induced charge value, and determine the installation distance coefficient (i.e., k A ) according to the installation distance value (i.e., d A ).

[0098] Firstly, the installation distance value (i.e., d A ) corresponding to the proportional coefficient of the induced charge value (i.e., k0) is looked up and obtained; then, the installation distance coefficient (i.e., k A ) corresponding to the installation distance value (i.e., d A ) is looked up and obtained.

[0099] Exemplarily, in the storage list, the proportional coefficient of the induced charge value, the installation distance value and the installation distance coefficient having the corresponding relationship are stored. When the proportional coefficient of the induced charge value is determined to be 0.8, the installation distance value corresponding to the coefficient is obtained to be 5.5 cm and the installation distance coefficient is 1.2 according to the corresponding relationship.

[0100] In the first embodiment, since the first sensing electrode and the second sensing electrode are in different planes, the first current signal and the second current signal having the signal difference value can be induced, and the first induced charge value and the second induced charge value having the signal difference value can be obtained. The electrostatic voltage value can be obtained through the first induced charge value and the installation distance coefficient, or the second induced charge value and the installation distance coefficient, so that the distance compensation can be realized without setting the distance detection module, the volume of the electrostatic sensor is reduced, and the processing cost is lowered. At the same time, the application environment and the measured object of the sensor are limited due to the different measurement principles of the distance detection module and the electrostatic sensor (such as the specific requirement of the optical distance detection module on the color of the measured object).

[0101] In addition, the installation distance value and the installation distance coefficient can be obtained through the proportional coefficient of the induced charge value, and the installation position of the electrostatic sensor can be accurately obtained, so that the electrostatic voltage value of the current environment or the measured object can be detected.

[0102] Embodiment two

[0103] As Figure 2 and Figure 7As shown, the embodiment provides a distance compensation type resonant electrostatic sensor, which is different from the electrostatic sensor in embodiment one in that:

[0104] The first shielding structure is connected with the first vibrating beam and periodically vibrates with the first vibrating beam, and is located directly above the first sensing electrode and the second sensing electrode. The second shielding structure is connected with the second vibrating beam and periodically vibrates with the second vibrating beam, and is located directly above the first sensing electrode and the second sensing electrode.

[0105] The first shielding structure and the second shielding structure both cover part of the top end face of the first sensing electrode and the second sensing electrode, and a reserved interval is formed between the first shielding structure and the second shielding structure; in a non-vibration state, the top end face of the first sensing electrode forms a shielding area a and a non-shielding area a, and the top end face of the second sensing electrode forms a shielding area b and a non-shielding area b.

[0106] Specifically, the first shielding structure is a shielding electrode a 15, and the second shielding structure is a shielding electrode b 16, wherein the shielding electrode a 15 corresponds to the shielding electrode b 16 and is in the same plane, and a reserved interval a is formed between the shielding electrode a 15 and the shielding electrode b 16.

[0107] Further, a shielding electrode a mounting area is formed on the first vibrating beam 4, wherein the shielding electrode a mounting area is a local area a formed on the top end face of the first vibrating beam 4. The shielding electrode a 15 is arranged in a transverse horizontal direction relative to the first vibrating beam 4, and includes a curved part a and a flat plate part a connected with each other, a first end of the curved part a is connected with the local area a, and the flat plate part a is located above the interval area, so that part of the flat plate part a is located directly above the first sensing electrode 1 and the second sensing electrode 2. In a non-vibration state, the flat plate part a covers part of the top end face of the first sensing electrode 1 and the second sensing electrode 2.

[0108] A shielding electrode b mounting area is formed on the second vibrating beam 8, wherein the shielding electrode b mounting area is a local area b formed on the top end face of the second vibrating beam 8. The shielding electrode b 16 is arranged in a transverse horizontal direction relative to the second vibrating beam, and includes a curved part b and a flat plate part b connected with each other, a first end of the curved part b is connected with the local area b, and the flat plate part b is located above the interval area, so that part of the flat plate part b is located directly above the first sensing electrode 1 and the second sensing electrode 2. In a non-vibration state, the flat plate part b covers part of the top end face of the first sensing electrode 1 and the second sensing electrode 2.

[0109] Furthermore, when the first vibration beam 4 and the shielding electrode a15 periodically vibrate to shield the first sensing electrode 1, a first current signal is generated. When the second vibration beam 8 and the shielding electrode b16 periodically vibrate to shield the second sensing electrode 2, a second current signal is generated. There is a signal difference between the first current signal and the second current signal, and the height difference (i.e., d0) is correlated with the signal difference.

[0110] Furthermore, the height difference (ie, d0) is proportional to the signal difference (ie, the greater the height difference, the greater the signal difference, and the smaller the height difference, the smaller the signal difference).

[0111] Example 3

[0112] like Figures 3 to 7 As shown, this embodiment provides a distance-compensated resonant electrostatic sensor. The difference between this electrostatic sensor and the electrostatic sensor in the second embodiment is that:

[0113] The first shielding structure includes a first shielding electrode 5 and a third shielding electrode 6 that are spaced apart from each other and are located in the same plane or different planes. The second shielding structure includes a second shielding electrode 9 and a fourth shielding electrode 10 that are spaced apart from each other and are located in the same plane or different planes. The first shielding electrode 5 corresponds to the second shielding electrode 9 and is located in the same plane. A reserved gap a is formed between the first shielding electrode 5 and the second shielding electrode 9. The third shielding electrode 6 corresponds to the fourth shielding electrode 10 and is located in the same plane. A reserved gap b is formed between the third shielding electrode 6 and the fourth shielding electrode 10.

[0114] Specifically, a first shielding electrode mounting area and a third shielding electrode mounting area are formed on the first vibration beam 4, each spaced apart from the other. The first shielding electrode mounting area is a localized area a formed on the top end surface of the first vibration beam 4, and the third shielding electrode mounting area is a recessed area a formed on the top end surface of the first vibration beam 4. The localized area a is closer to the first end of the first vibration beam 4 than the recessed area a. The localized area a is positioned higher than the recessed area a. When the first shielding electrode 5 is connected to the localized area a and the third shielding electrode 6 is connected to the recessed area a, the first shielding electrode 5 is positioned higher than the third shielding electrode 6.

[0115] The first shielding electrode 5 and the third shielding electrode 6 are arranged in a transverse horizontal direction relative to the first vibrating beam 4, wherein the first shielding electrode 5 comprises a curved portion a and a flat portion a connected to each other, and the second shielding electrode 9 comprises a curved portion b and a flat portion b connected to each other. The first end of the curved portion a is connected to the local area a, and the flat portion a is located above the interval area, so that part of the flat portion a is located directly above the first sensing electrode 1. The first end of the curved portion b is connected to the top end surface of the recessed area a, and the flat portion b is located above the interval area, so that part of the flat portion b is located directly above the second sensing electrode 2. In the non-vibration state, the flat portion a covers part of the top end surface of the first sensing electrode 1, and the flat portion b covers part of the top end surface of the second sensing electrode 2.

[0116] The second vibrating beam 8 is formed with a second shielding electrode mounting area and a fourth shielding electrode mounting area, wherein the second shielding electrode mounting area is a local area b formed on the top end surface of the second vibrating beam 8, and the fourth shielding electrode mounting area is a recessed area b formed on the top end surface of the second vibrating beam 8, and the local area b is closer to the first end of the second vibrating beam 8 relative to the recessed area b. The position of the local area b is higher than that of the recessed area b, and when the second shielding electrode 9 is connected to the local area b and the fourth shielding electrode 10 is connected to the recessed area b, the position of the second shielding electrode 9 is higher than that of the fourth shielding electrode 10.

[0117] The second shielding electrode 9 and the fourth shielding electrode 10 are arranged in a transverse horizontal direction relative to the second vibrating beam 8, wherein the second shielding electrode 9 comprises a curved portion c and a flat portion c connected to each other, and the second shielding electrode 9 comprises a curved portion d and a flat portion d connected to each other. The first end of the curved portion c is connected to the local area b, and the flat portion c is located above the interval area, so that part of the flat portion c is located above the first sensing electrode 1. The first end of the curved portion d is connected to the top end surface of the recessed area b, and the flat portion d is located above the interval area, so that part of the flat portion d is located above the second sensing electrode 2. In the non-vibration state, the flat portion c covers part of the top end surface of the first sensing electrode 1, and the flat portion d covers part of the top end surface of the second sensing electrode 2.

[0118] Further, when the first shielding electrode 5 and the third shielding electrode 6 periodically vibrate to shield the first sensing electrode 1, a first current signal is generated, and when the second shielding electrode 9 and the fourth shielding electrode 10 periodically vibrate to shield the second sensing electrode 2, a second current signal is generated, wherein there is a signal difference between the first current signal and the second current signal, and the height difference (i.e., d0) and the signal difference have a correlation.

[0119] Further, the height difference value (i.e., d0) is proportional to the signal difference value (i.e., the greater the height difference value, the greater the signal difference value, and the smaller the height difference value, the smaller the signal difference value).

[0120] On the basis of embodiment one, in embodiment two and embodiment three, by increasing the first shielding structure and the second shielding structure, when the first sensing electrode and the second sensing electrode sense the first current signal and the second current signal, the sensitivity of the first sensing electrode and the second sensing electrode can be increased, and the accuracy of the first current signal and the second current signal can be improved.

[0121] In addition, since the first shielding structure and the second shielding structure form a reserved interval therebetween, when the first vibrating beam and the second vibrating beam perform periodic vibration, the first shielding structure and the second shielding structure are prevented from colliding, and the working state of the electrostatic sensor is not affected.

[0122] In embodiment one to embodiment three, the symmetric characteristic of the tuning fork resonant structure is utilized to arrange the upper and lower staggered electrode structures having a distance difference with respect to the measured object. Under a fixed distance, since the electric field on the first sensing electrode and the electric field on the second sensing electrode are in a constant proportion, when the electric field amplitude ratio of the two is unchanged and only the electric field amplitude changes, it can be considered that the electrostatic sensor does not change the distance. When the distance of the two with respect to the measured object changes, the electric field proportion relationship also changes. Therefore, the relative distance change of the electrostatic sensor with respect to the measured object can be determined through the corresponding relationship between the electric field proportion on the two sensing electrodes with a height difference and the distance, so as to realize distance compensation.

[0123] Embodiment four

[0124] As shown in Figure 8 The embodiment provides a detection method, which is applied to the distance compensation type resonant electrostatic sensor provided in embodiment one and includes the following steps:

[0125] S1, in a current electric field environment, the first sensing electrode and the second sensing electrode on different planes are periodically vibrated to generate a first current signal and a second current signal with a signal difference value;

[0126] S2, the first current signal and the second current signal are respectively converted into a first electric field value and a second electric field value;

[0127] S3, a first sensing charge value, a second sensing charge value and an installation distance coefficient are respectively obtained according to the first electric field value and the second electric field value, and an electrostatic voltage value is obtained according to the first sensing charge value and the installation distance coefficient or the second sensing charge value and the installation distance coefficient.

[0128] Embodiment five

[0129] As shown in Figure 9 The embodiment provides a detection method, which is a specific implementation step of the detection method in Embodiment 2, and includes the following steps.

[0130] S201, a first current signal and a second current signal with a signal difference are sensed.

[0131] Specifically, the first sensing electrode and the second sensing electrode sense charges in the current electric field environment to generate current signals, which are conducted to the first vibrating beam and the second vibrating beam through the anchor point; the feedback stress generated by the second vibrating beam generates a feedback signal through the feedback electrode and is transmitted to the self-oscillation circuit; the self-oscillation circuit generates a driving signal according to the received feedback signal and transmits it to the driving electrode; the driving electrode generates a driving stress according to the received driving signal, so that the first vibrating beam vibrates, thereby realizing periodic vibration shielding between the first vibrating beam and the first sensing electrode, the second sensing electrode, and the second vibrating beam and the first sensing electrode, the second sensing electrode, to generate the first current signal and the second current signal with the signal difference.

[0132] Further, the height difference (i.e., d0) is proportional to the signal difference (i.e., the greater the height difference, the greater the signal difference, and the smaller the height difference, the smaller the signal difference).

[0133] S202, a first voltage signal and a second voltage signal are obtained.

[0134] Specifically, the first sensing electrode is connected with the first IV conversion circuit, the second sensing electrode is connected with the second IV conversion circuit, the first current signal is input into the first IV conversion circuit, and the first current signal is converted into the first voltage signal through the first IV conversion circuit. The second current signal is input into the second IV conversion circuit, and the second current signal is converted into the second voltage signal through the second IV conversion circuit.

[0135] Further, there is a difference between the first voltage signal and the second voltage signal.

[0136] S203, a first electric field simulation value and a second electric field simulation value are obtained.

[0137] Specifically, the first IV conversion circuit and the second IV conversion circuit are both connected with the modulation circuit, and the first voltage signal and the second voltage signal are input into the modulation circuit. The modulation circuit modulates the first voltage signal and the second voltage signal to form the first electric field simulation value and the second electric field simulation value.

[0138] Further, there is a difference between the first electric field simulation value and the second electric field simulation value.

[0139] S204, a digitized first electric field value and a digitized second electric field value are obtained.

[0140] Specifically, the modulation circuit is connected with the ADC sampling circuit, and the first electric field analog value and the second electric field analog value are input into the ADC sampling circuit. The ADC sampling circuit converts the first electric field analog value and the second electric field analog value into a digitized first electric field value and a digitized second electric field value respectively.

[0141] Further, there is a difference between the first electric field value and the second electric field value.

[0142] S205, obtain the first induced charge value, the second induced charge value, and the proportion coefficient of the induced charge value of the first induced charge value and the second induced charge value.

[0143] Specifically, the first calculation unit obtains the first induced charge value and the second induced charge value according to the first electric field value and the second electric field value respectively, and obtains the proportion coefficient of the induced charge value by using the following formula:

[0144]

[0145] wherein k0 is the proportion coefficient of the induced charge value, Q A is the first induced charge value, Q B is the second induced charge value.

[0146] S206, obtain the installation distance value according to the proportion coefficient of the induced charge value, and obtain the installation distance coefficient according to the installation distance value.

[0147] Specifically, the second calculation unit obtains the installation distance value (i.e., d A ) according to the proportion coefficient of the induced charge value (i.e., k0) and the height difference value (i.e., d0), and by using the following formula:

[0148]

[0149] wherein k0 is the proportion coefficient of the induced charge value, d A is the proportion coefficient of the induced charge value, and d0 is the height difference value.

[0150] After obtaining the installation distance value (i.e., d A ) corresponding thereto, the installation distance coefficient (i.e., k A ) corresponding thereto is searched and obtained according to the installation distance value (i.e., d A ).

[0151] S207, obtain the electrostatic voltage value.

[0152] Specifically, the first induced charge value and the installation distance coefficient are used to obtain the electrostatic voltage value of the current electric field environment or the electrostatic voltage value of the measured object by using the following formula:

[0153] U=k A xQ A ,

[0154] wherein, U is the electrostatic voltage value, k A is the installation distance coefficient, Q A is the first induced charge value.

[0155] Alternatively, the second induced charge value and the installation distance coefficient are used to obtain the electrostatic voltage value of the current electric field environment or the electrostatic voltage value of the measured object by the following formula:

[0156] U=k A xQ B ,

[0157] wherein, U is the electrostatic voltage value, k A is the installation distance coefficient, Q B is the second induced charge value.

[0158] In addition, in another possible embodiment, in the above S206, the installation distance value (i.e., d A ) corresponding to the proportion coefficient (i.e., k0) of the induced charge value can also be searched and obtained; then, the installation distance coefficient (i.e., k A ) corresponding to the installation distance value (i.e., d A ) is searched and obtained.

[0159] Exemplarily, a storage list is provided, which stores the proportion coefficient of the induced charge value, the installation distance value and the installation distance coefficient having a corresponding relationship; after the proportion coefficient of the induced charge value is determined, the installation distance value and the installation distance coefficient can be sequentially obtained according to the corresponding relationship.

[0160] In the above embodiment, since the first sensing electrode and the second sensing electrode are in different planes, the first current signal and the second current signal having a signal difference value can be sensed, and the first induced charge value and the second induced charge value having a signal difference value can be obtained; the electrostatic voltage value can be obtained through the first induced charge value and the installation distance coefficient or the second induced charge value and the installation distance coefficient, so that the distance compensation is realized without the need of setting a distance detection module, and the volume of the electrostatic sensor is reduced and the processing cost is lowered.

[0161] The above only describes the preferred embodiments of the present application, which are only illustrative but not restrictive. Those skilled in the art understand that many changes, modifications and even equivalents can be made to the present application within the spirit and scope defined by the claims of the present application, and all of them will fall into the protection scope of the present application.

Claims

1. A distance-compensated resonant electrostatic sensor, comprising a connected sensitive structure and a circuit board with a signal processing portion fixed thereon, wherein the sensitive structure comprises a first vibration beam, a second vibration beam, a drive electrode, a feedback electrode, and an anchor point, characterized in that: At least a first sensing electrode and a second sensing electrode are provided on the circuit board, the first sensing electrode and the second sensing electrode being located in different planes and between the first vibration beam and the second vibration beam. When the first vibration beam and the second vibration beam periodically vibrate to shield the first sensing electrode and the second sensing electrode, a first current signal and a second current signal having a signal difference are generated. The height of the first sensing electrode is different from the height of the second sensing electrode, so that the top end surface of the first sensing electrode and the top end surface of the second sensing electrode are located in different planes; There is a height difference between a top end surface of the first sensing electrode and a top end surface of the second sensing electrode, and the height difference is correlated with the signal difference; The signal processing part derives a first induced charge value, a second induced charge value and an installation distance coefficient according to the first current signal and the second current signal, respectively, and derives an electrostatic voltage value according to the first induced charge value and the installation distance coefficient, or the second induced charge value and the installation distance coefficient.

2. A distance-compensated resonant electrostatic sensor according to claim 1, characterized in that: A first shielding structure is provided on the first vibration beam and is connected to the first vibration beam and periodically vibrates with the first vibration beam, wherein the first shielding structure is located directly above the first sensing electrode and the second sensing electrode; A second shielding structure is provided on the second vibration beam and is connected to the second vibration beam and periodically vibrates along with the second vibration beam. The second shielding structure is located directly above the first sensing electrode and the second sensing electrode.

3. The distance-compensated resonant electrostatic sensor according to claim 2, characterized in that: The first shielding structure and the second shielding structure both cover a portion of the top end surfaces of the first sensing electrode and the second sensing electrode, and a reserved gap is formed between the first shielding structure and the second shielding structure; In a non-vibrating state, the top end surface of the first sensing electrode forms a shielding area a and an unshielded area a, and the top end surface of the second sensing electrode forms a shielding area b and an unshielded area b.

4. The distance-compensated resonant electrostatic sensor according to claim 3, characterized in that: The first shielding structure is a shielding electrode a, and the second shielding structure is a shielding electrode b, wherein the shielding electrode a corresponds to the shielding electrode b and is located in the same plane, and the reserved gap a is formed between the shielding electrode a and the shielding electrode b.

5. The distance-compensated resonant electrostatic sensor according to claim 3, characterized in that: The first shielding structure includes at least a first shielding electrode and a third shielding electrode that are spaced apart from each other and are located in the same plane or different planes. The second shielding structure includes at least a second shielding electrode and a fourth shielding electrode that are spaced apart from each other and are located in the same plane or different planes. The first shielding electrode corresponds to the second shielding electrode and is located in the same plane. A reserved gap a is formed between the first shielding electrode and the second shielding electrode. The third shielding electrode corresponds to the fourth shielding electrode and is located in the same plane. A reserved gap b is formed between the third shielding electrode and the fourth shielding electrode.

6. The distance-compensated resonant electrostatic sensor according to claim 1, characterized in that: The signal processing part includes a self-excited oscillation circuit, a signal processing module and a solution module, wherein: The self-excited oscillation circuit is connected to the feedback electrode and the driving electrode respectively, and the self-excited oscillation circuit receives the feedback signal input by the feedback electrode and inputs the driving signal to the driving electrode; The signal processing module converts the first current signal and the second current signal into a first electric field value and a second electric field value respectively; The solution module calculates a first induced charge value, a second induced charge value, and an installation distance coefficient according to the first electric field value and the second electric field value, and calculates an electrostatic voltage value according to the first induced charge value and the installation distance coefficient, or the second induced charge value and the installation distance coefficient.

7. The distance-compensated resonant electrostatic sensor according to claim 6, characterized in that: The signal processing module includes a first IV conversion circuit, a second IV conversion circuit, a modulation circuit and an ADC sampling circuit, wherein: The first IV conversion circuit converts the first current signal into a first voltage signal; The second IV conversion circuit converts the second current signal into a second voltage signal; The modulation circuit modulates the first voltage signal and the second voltage signal to form a first electric field analog value and a second electric field analog value; The ADC sampling circuit converts the first electric field analog value and the second electric field analog value into the first electric field value and the second electric field value respectively.

8. The distance-compensated resonant electrostatic sensor according to claim 6, characterized in that: The solution module includes a first calculation unit, a second calculation unit and a third calculation unit, wherein: The first calculation unit is used to calculate a first induced charge value and a second induced charge value according to the first electric field value and the second electric field value, and to calculate a proportional coefficient of the induced charge value according to the first induced charge value and the second induced charge value; The second calculation unit is configured to calculate an installation distance value according to a proportionality coefficient of the induced charge value and the height difference, and determine an installation distance coefficient according to the installation distance value; The third calculation unit is configured to obtain an electrostatic voltage value according to the first induced charge value and the installation distance coefficient, or the second induced charge value and the installation distance coefficient.

9. A detection method, applied to a distance-compensated resonant electrostatic sensor according to any one of claims 1 to 8, characterized in that: The following steps are involved: In the current electric field environment, the first sensing electrode and the second sensing electrode located in different planes vibrate periodically to generate a first current signal and a second current signal having a signal difference; Converting the first current signal and the second current signal into a first electric field value and a second electric field value respectively; A first induced charge value, a second induced charge value, and an installation distance coefficient are respectively derived according to the first electric field value and the second electric field value, and an electrostatic voltage value is derived according to the first induced charge value and the installation distance coefficient, or the second induced charge value and the installation distance coefficient.

10. The detection method according to claim 9, characterized in that: The step of deriving a first induced charge value, a second induced charge value, and an installation distance coefficient based on the first electric field value and the second electric field value, and deriving an electrostatic voltage value based on the first induced charge value and the installation distance coefficient or the second induced charge value and the installation distance coefficient, includes: Calculating the first electric field value and the second electric field value respectively to obtain a first induced charge value and a second induced charge value; Calculating the first induced charge value and the second induced charge value to obtain a proportionality coefficient of the induced charge values; determining a current installation distance value of the electrostatic sensor according to a proportionality coefficient of the induced charge value; determining an installation distance coefficient according to the installation distance value; The first induced charge value and the installation distance coefficient, or the second induced charge value and the installation distance coefficient, are calculated to obtain an electrostatic voltage value.

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