Parallel clamping plate-shaped vibration electrode for static detection

Abstract

The utility model discloses a parallel clamping plate-shaped vibration electrode for static detection, and belongs to the field of charge electric quantity measurement. Comprising a pair of parallel clamping plate electrodes arranged in a mirror image mode. Each parallel clamping plate electrode consists of an external electrode plate and an internal electrode plate; a piezoelectric ceramic piece is arranged between the external electrode piece and the internal electrode piece; the external electrode plate, the internal electrode plate and the piezoelectric ceramic plate are fixedly connected into a whole; the parallel clamping plate electrode is fixed on the circuit board through an external electrode plate; an electrostatic induction electrode is arranged at one end of the parallel clamping plate electrode; the electrostatic induction electrodes are independently fixed on the circuit board; the external electrode plate is electrically connected with the circuit board; and the internal electrode plate is connected with zero volt voltage. A point fixing mode of a vibration electrode is changed into a surface fixing mode; the function (main) vibration direction is parallel to the length direction of the vibration electrode, and the piezoelectric ceramic piece completely covers the vibration electrode piece; and interference vibration and stray capacitance signals caused by the interference vibration can be effectively reduced, so that the detection result is more accurate, and the stability is better.

Description

Technical Field

[0001] The utility model belongs to the field of charge and electrical quantity measuring devices, and in particular relates to a vibration detection electrode for detecting static voltage on the surface of an object. Background Art

[0002] The electrostatic voltage sensor is a professional and key instrument for detecting static charge on the surface of objects. The accuracy and stability of its detection data play a very important role in the electrostatic protection of electrostatic sensitive devices.

[0003] At present, most of the mainstream electrostatic voltage sensors on the market adopt non-contact detection methods. They use the principle of electrostatic induction to bring the vibrating capacitive test probe close to the charged body, and use the distorted electric field generated between the probe and the charged body to test the surface potential of the charged body. In essence, it is a test of the electric field on the surface of the charged body.

[0004] Since this test does not directly contact the charged body, it is also called non-contact measurement, and the electrostatic voltage sensor used is also called non-contact electrostatic voltage sensor.

[0005] Compared with contact measurement, non-contact measurement results are less affected by the instrument input capacitance and input resistance, and its measurement accuracy is closely related to the mechanical / electrical structure of the vibrating electrode in the electrostatic induction sensor.

[0006] Therefore, continuously optimizing the electrical structure design of the vibrating electrode is of great significance to the detection performance of the non-contact electrostatic voltage sensor.

[0007] The typical structure of the existing vibration electrode can be found in the two patents previously applied by the applicant: the invention patent "A portable electrostatic detection device and electrostatic detection method thereof" with the authorization announcement date of 2013.11.13 and the authorization announcement number of CN 102353855 B, and the utility model patent "An electrostatic sensor detection head" with the authorization announcement date of 2019.10.11 and the authorization announcement number of CN 209486193U; the specific structure of the vibration electrode is as follows: Figure 1 As shown in Figure 2, a sensor bracket and a charge sensing sheet are arranged on the circuit board f. The cross section of the sensor bracket is a gate-shaped structure, which is composed of two vertical vertical edges of the sensor bracket and the top horizontal edge of the sensor bracket; the charge sensing sheet is arranged vertically to the circuit board.

[0008] In this technical solution, two vibration plates d are symmetrically arranged and connected together through a special-shaped connecting plate a located at the rear; the two vibration plates are fixed above the circuit board through the four supporting plates b at the rear, and through the welding feet b' at the bottom of the supporting plates, a "point" fixed structure is formed and fixedly welded on the circuit board. Two piezoelectric ceramic plates c are located in front of the special-shaped connecting plate and are symmetrically arranged on the inner surface of the two vibration plates; the two piezoelectric ceramic plates are electrically connected to the circuit board f through the lead wire c'; the static charge sensing electrode e is independently arranged at the front end of the vibration plate. It uses piezoelectric ceramics to make the two longitudinal vertical edges of the sensor bracket produce lateral vibrations, forming an action mode similar to the vibration of a tuning fork, and the charge sensing plate is used to receive the action signal generated by the external static charge. It can effectively prevent the interference of the outside world on the electrostatic sensing signal; fundamentally solve the problem of quantitative detection of static electricity, and the subsequent amplification / processing of the monitoring data is easy, the repeatability of the detection data is good, and the accuracy and stability of static detection are improved; it helps to ensure the product qualification rate of the electrostatic sensor.

[0009] However, in actual use, it is found that the existing technical solutions have the following technical defects:

[0010] 1) The fixing method of the vibration electrode is "point" fixing (also known as "point" fixing method), which is not conducive to regular vibration in the functional vibration direction (also known as the main vibration direction), and will form interfering vibrations in other directions, forming stray capacitance signals between the static charge sensing electrode, causing distortion of the functional detection signal, and failing to form a standard sinusoidal wave signal on the static charge sensing electrode, which is not conducive to the detection result;

[0011] 2) The functional vibration direction of the vibrating plate (also called the main vibration direction, referred to as the functional (main) vibration direction) is perpendicular to the length direction of the vibrating plate, that is, a transverse wave vibration is formed (see Figure 2-1 , Figure 2-2 As shown in , the vibration electrode cannot quickly reach a stable vibration state, and because the piezoelectric ceramic sheet only covers a small area of ​​the vibration plate, this structural mode setting is not conducive to the vibration electrode quickly forming a stable vibration state, resulting in poor stability of the detection signal.

[0012] How to reduce the interfering vibration of the vibrating electrode and the stray capacitance signal caused by it, so that the detection results of the non-contact electrostatic voltage sensor are more accurate and more stable, is a practical technical problem that needs to be solved urgently in actual research and development work. Utility Model Content

[0013] The technical problem to be solved by the utility model is to provide a parallel clamping plate-shaped vibration electrode for electrostatic detection. It adopts a parallel clamping plate-type vibration electrode structure with a layered composite structure, and changes the "point" fixing method to a "surface" fixing method; its functional (main) vibration direction is parallel to the length direction of the vibration electrode, forming a longitudinal wave vibration mode, and the piezoelectric ceramic sheet fully covers the vibration electrode sheet; in this way, it can effectively reduce interfering vibrations and the stray capacitance signals caused by them, making the detection results more accurate and more stable.

[0014] The technical solution of the utility model is to provide a parallel clamping plate-shaped vibration electrode for electrostatic detection, including a vibration electrode for electrostatic detection, which is characterized by:

[0015] The vibrating electrode comprises a pair of parallel clamping plate electrodes arranged in mirror images of each other;

[0016] Each parallel clamping plate electrode is composed of two mutually parallel rectangular electrode sheets, namely an outer electrode sheet and an inner electrode sheet; a piezoelectric ceramic sheet is arranged between the outer electrode sheet and the inner electrode sheet; the outer electrode sheet, the inner electrode sheet and the piezoelectric ceramic sheet are fixedly connected as a whole to form a parallel clamping plate electrode with a layered composite structure;

[0017] Each of the parallel clamping plate electrodes is fixed on the circuit board through an external electrode sheet;

[0018] A rectangular electrostatic induction electrode is arranged at one end of the parallel clamping plate electrode; a side of the rectangular electrostatic induction electrode facing away from the parallel clamping plate electrode group is a sensing surface / detection surface of the electrostatic charge induction electrode; the rectangular electrostatic induction electrode is independently fixed on the circuit board;

[0019] The external electrode sheet is electrically connected to the circuit board that fixes the vibration electrode; the internal electrode sheet is connected to a zero volt voltage.

[0020] Specifically, the rectangular electrode sheet is a metallic rectangular electrode sheet.

[0021] Specifically, the pair of parallel clamping plate electrodes are arranged in a mirror image with respect to each other along the length direction.

[0022] Specifically, in the pair of parallel clamping plate electrodes, the planes where the electrode sheets inside the two parallel clamping plate electrodes are located are arranged facing each other and are mirror images of each other.

[0023] Furthermore, the external electrode sheet and the internal electrode sheet have the same shape and are arranged in parallel.

[0024] Furthermore, the piezoelectric ceramic sheet has the same shape as the internal electrode sheet; the piezoelectric ceramic sheet completely covers the internal electrode sheet; and the mechanical vibration frequency of the internal electrode sheet is consistent with the driving voltage frequency of the piezoelectric ceramic sheet.

[0025] Specifically, each of the parallel clamping plate electrodes is fixed on the circuit board through the outer surface of its external electrode sheet, forming a "surface contact" type fixing structure.

[0026] Furthermore, a rectangular electrostatic induction electrode is arranged in front of the parallel clamping plate electrodes that are mirror images of each other in the vibration direction, and the central axis of the sensing surface / detection surface of this electrostatic charge induction electrode coincides with the central axis of the parallel clamping plate electrodes that are mirror images of each other in the vibration direction, and the electrostatic induction electrode is located inside the electrostatic sensor housing.

[0027] Furthermore, the functional vibration direction / main vibration direction of the parallel plate electrodes is parallel to the length direction of the parallel plate electrodes, forming a longitudinal wave vibration mode.

[0028] Specifically, the parallel clamp-shaped vibration electrode electrically connects the sinusoidal voltage to the external electrode sheet through a circuit board that fixes the vibration electrode, and connects the internal electrode sheet to a zero volt voltage through a lead wire;

[0029] In this way, the piezoelectric ceramic sheet located between the external electrode sheet and the internal electrode sheet is driven to generate a reciprocating motion along the length direction of the parallel clamp-shaped vibration electrode or the piezoelectric ceramic sheet, forming a longitudinal wave vibration mode, and finally forming a standard sinusoidal oscillation capacitance with the electrostatic charge sensing electrode, and a standard sinusoidal signal is detected on the electrostatic charge sensing electrode.

[0030] Compared with the prior art, the advantages of the utility model are:

[0031] 1. The parallel clamping plate type vibration electrode of this technical solution changes the existing "point" fixing method of the vibration electrode to a "surface" fixing method, strengthens the constraint on the vibration electrode, greatly reduces the interfering vibration in the non-functional (main) vibration direction during the vibration process, effectively suppresses the generation of stray capacitance signals, and improves the accuracy of the detection results;

[0032] 2. The parallel clamping plate type vibration electrode of the technical solution has a functional (main) vibration direction parallel to the length direction of the vibration plate, forming a longitudinal wave vibration, and the piezoelectric ceramic sheet fully covers the vibration plate, so that the vibration electrode can quickly reach a stable vibration state and enhance the stability of the detection signal;

[0033] 3. Compared with the existing vibration electrode vibrating plate, the parallel clamping plate type vibration electrode of the present technical solution has almost no local deformation of the vibration electrode plate because the piezoelectric ceramic plate fully covers the vibration electrode plate, and only generates the overall vibration / movement of the vibration plate (comparison Figure 2-1 , 2-2 and Figure 5 , Figure 6 Its mechanical vibration frequency is consistent with its driving voltage frequency, that is, the vibration frequency is completely controlled by the driving voltage frequency; in this way, the driving voltage frequency can be adjusted according to the change of the static power source, so that the vibration frequency can better adapt to the field process changes and enhance the applicability to the field environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of an existing electrostatic detection electrode;

[0035] Figure 2a It is a schematic diagram of the unfolded planar structure of an existing electrostatic detection electrode;

[0036] Figure 2b A schematic diagram of the side view structure of an existing electrostatic detection electrode;

[0037] Figure 2c and Figure 2d It is a schematic diagram of the left and right view structure of the existing electrostatic detection electrode;

[0038] Figure 2e It is a schematic diagram of the top view structure of the existing electrostatic detection electrode;

[0039] Figure 2-1 A schematic diagram of the simulation of the vibration / movement mode of the existing electrostatic detection electrode;

[0040] Figure 2-2 It is another simulation schematic diagram of the vibration / movement mode of the existing electrostatic detection electrode;

[0041] Figure 3 This is a schematic diagram of the three-dimensional structure of the electrostatic detection electrode of the technical solution as seen from one end of the parallel clamping plate electrode;

[0042] Figure 3-1 This is a schematic diagram of the top view of the electrostatic detection electrode of this technical solution;

[0043] Figure 3-2 This is a schematic diagram of the three-dimensional structure of the static detection electrode of the technical solution as seen from one end of the static charge sensing electrode;

[0044] Figure 4 This is a flowchart of the simulation comparison test of the electrostatic detection electrode structure of this technical solution;

[0045] Figure 5This is a simulation diagram of the vibration / movement mode of the electrostatic detection electrode of this technical solution;

[0046] Figure 6 This is another simulation diagram of the vibration / movement mode of the electrostatic detection electrode of the technical solution;

[0047] Figure 7 is the X-component diagram of the interference displacement of the existing electrostatic detection electrode;

[0048] Figure 8 It is the functional (main) displacement Y component diagram of the existing electrostatic detection electrode;

[0049] Fig. 9 is a diagram of the interfering displacement Z component of the existing electrostatic detection electrode;

[0050] Fig.10 This is the functional (main) displacement X-component diagram of the electrostatic detection electrode of this technical solution;

[0051] Fig.11 This is the Y component diagram of the interfering displacement of the electrostatic detection electrode of this technical solution;

[0052] Fig.12 This is the Z component diagram of the interfering displacement of the electrostatic detection electrode of this technical solution;

[0053] Fig.13 This is a comparison diagram of the functional (main) displacement of the present technical solution and the existing electrostatic detection electrode;

[0054] Figure 13-1 This is a comparison diagram of the functional (main) displacement vibration waveform and the driving voltage waveform of the technical solution and the existing electrostatic detection electrode;

[0055] Fig.14 This is a comparison diagram of the interference displacement between this technical solution and the existing electrostatic detection electrode.

[0056] Figure 1 to Figure 2-2 In the figure: a is a special-shaped connecting piece, b is a supporting piece, b′ is a welding foot, c is a piezoelectric ceramic piece, c′ is a lead, d is a vibrating piece, e is an electrostatic charge sensing electrode, and f is a circuit board; o is a displacement analysis point selected in the prior art solution;

[0057] Figures 3 to 14 In the figure, A and A' are parallel plate electrodes, 1 is an outer rectangular electrode sheet, 1-1 is the outer surface of the outer rectangular electrode sheet, 2 is an inner rectangular electrode sheet, 3 is a piezoelectric ceramic sheet, 4 is an electrostatic charge sensing electrode, 4-1 is the sensing surface / detection surface of the electrostatic charge sensing electrode, and o' is a selected point for displacement analysis of the present technical solution;

[0058] h is the spacing distance between the two parallel clamping plate electrodes A and A', h1 is the thickness of the outer rectangular electrode sheet, h2 is the thickness of the inner rectangular electrode sheet, h3 is the thickness of the piezoelectric ceramic sheet, and M is the central axis in the vibration direction of the rectangular electrostatic induction electrode sensing surface / detection surface and the parallel clamping plate electrodes that are mirrored to each other. DETAILED DESCRIPTION

[0059] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0060] 1. This technical solution is achieved by adopting the following structure:

[0061] A pair of parallel clamping plate electrodes are arranged, each of which includes two metal rectangular electrode sheets which are parallel and overlapped with each other, and a piezoelectric ceramic sheet is sandwiched in the middle. The three are bonded or fixed together by conductive glue.

[0062] The distance between the two parallel clamping plate electrodes that are mirror images of each other can be set according to the needs of electrostatic detection.

[0063] The sizes of the two parallel clamping plate electrodes, the metal rectangular electrode sheets and the piezoelectric ceramic sheets in the middle sandwich, especially the thickness, can be set according to the needs of electrostatic detection.

[0064] The outermost metal rectangular electrode piece is fixedly soldered to the circuit board to restrict its movement.

[0065] A rectangular electrostatic induction electrode is arranged in front of the parallel clamping plate electrodes that are mirror images of each other in the vibration direction. The central axis of the sensing surface (i.e., the detection surface) of this rectangular electrostatic induction electrode coincides with the central axis of the parallel clamping plate electrodes that are mirror images of each other in the vibration direction, and is located inside the electrostatic sensor housing.

[0066] The rectangular electrostatic induction electrode can adjust the relative position of the parallel clamping plate electrodes mirroring each other on the central axis where the sensing surface / detection surface is located according to the electrostatic detection needs. The rectangular electrostatic charge sensing electrode can also be set in size according to the electrostatic detection needs.

[0067] A sinusoidal voltage is applied to the two outermost rectangular electrode sheets, and the two innermost rectangular electrode sheets are connected to a zero volt voltage to drive the middle piezoelectric ceramic sheet to generate a reciprocating motion (i.e., forming a longitudinal wave vibration) in the length direction (detection direction, i.e., the direction of the central axis where the rectangular electrostatic induction electrode sensing surface (detection surface) is located), ultimately forming a standard sinusoidal oscillation capacitance between the vibrating electrode and the electrostatic charge sensing electrode, and forming a standard sinusoidal signal on the electrostatic charge sensing electrode.

[0068] Second, the technical solution is described in detail below:

[0069] 1. See Figure 3 , Figure 3-1 As shown in, in the technical solution, a pair of parallel clamping plate electrodes A, A' which are mirror images of each other (along the length direction) are provided, and each of the parallel clamping plate electrodes A, A' comprises two mutually parallel and overlapping metal rectangular electrode sheets, namely, an external rectangular electrode sheet 1 of the electrostatic detection electrode (referred to as the external electrode sheet) and an internal rectangular electrode sheet 2 of the electrostatic detection electrode (referred to as the internal electrode sheet), and a piezoelectric ceramic sheet 3 is provided between each external electrode sheet and the internal electrode sheet.

[0070] Specifically, the parallel clamping plate-shaped vibrating electrode of the technical solution includes a pair of parallel clamping plate electrodes A and A' arranged in a mirror image;

[0071] Each parallel clamping plate electrode A or A' is composed of an outer electrode sheet and an inner electrode sheet;

[0072] A piezoelectric ceramic sheet is arranged between the external electrode sheet and the internal electrode sheet;

[0073] The outer electrode sheet and the inner electrode sheet have the same shape and are arranged in parallel;

[0074] The piezoelectric ceramic sheet has the same shape as the external electrode sheet and the internal electrode sheet;

[0075] The outer rectangular electrode sheet 1, the inner rectangular electrode sheet 2 and the piezoelectric ceramic sheet 3 are bonded / fixed together by conductive adhesive to form parallel clamping plate electrodes A and A' of a layered composite structure.

[0076] 2. Each of the parallel clamping plate electrodes A or A' is fixed on the circuit board through an external rectangular electrode sheet 1.

[0077] Furthermore, each parallel clamping plate electrode A or A' is fixed on the circuit board through the outer surface 1-1 of the outer rectangular electrode sheet.

[0078] 3. See Figure 3-1 As shown in FIG. 1 , the distance h between two parallel clamping plate electrodes A and A′ which are mirror images of each other can be set or adjusted according to the needs of electrostatic detection.

[0079] 4. The dimensions of the two parallel plate electrodes A and A', which are mirror images of each other, the outer rectangular electrode sheet 1 and the inner rectangular electrode sheet 2, and the piezoelectric ceramic sheet 3 in the middle sandwich, especially the dimensions related to thickness (see Figure 3-1 As shown in the figure, for example, the thickness h1 of the outer rectangular electrode sheet of the electrostatic detection electrode, the thickness h2 of the inner rectangular electrode sheet of the electrostatic detection electrode, and the thickness h3 of the piezoelectric ceramic sheet of the electrostatic detection electrode can be set or adjusted according to the needs of electrostatic detection.

[0080] For example, increasing the thickness h3 of the piezoelectric ceramic sheet 3 can increase the vibration amplitude of the internal rectangular electrode sheet 2, thereby increasing the vibration capacitance between the mirror-image parallel clamping plate electrodes and the rectangular electrostatic induction electrode 4, thereby enhancing the acceptance of electrostatic signals.

[0081] For another example, increasing the thickness h2 of the inner rectangular electrode sheet 2 can also increase the vibration capacitance between the inner rectangular electrode sheet and the electrostatic induction electrode 4 which are mirror images of each other, so as to enhance the receiving capability of the electrostatic signal.

[0082] 5. Solder the outer surface 1-1 of the outermost rectangular electrode sheet to the circuit board to keep it in a stationary state.

[0083] Since the outer surface 1-1 of the external rectangular electrode sheet is fixedly welded to the circuit board, the connection relationship between the rectangular electrode sheet and the circuit board in the present technical solution is a "surface contact" fixing method (referred to as "surface" fixing method); since the constraints on the mechanical structure of the vibrating electrode are strengthened, the interfering vibration in the non-functional (main) vibration direction during the vibration process is greatly reduced, which can effectively suppress the generation of stray capacitance signals, thereby improving the accuracy of the electrostatic detection results.

[0084] 6. A rectangular electrostatic induction electrode 4 is provided at one end of the parallel clamping plate electrodes A and A'.

[0085] The rectangular electrostatic induction electrodes 4 are independently fixed on the circuit board.

[0086] The side of the rectangular electrostatic induction electrode 4 facing away from the parallel clamping plate electrodes A, A' is the sensing surface / detection surface 4-1 of the electrostatic charge sensing electrode.

[0087] Furthermore, a rectangular electrostatic induction electrode 4 is arranged in front of the parallel clamping plate electrodes A and A' that are mirror images of each other in the vibration direction. The central axis M of the sensing surface / detection surface 4-1 of this electrostatic charge induction electrode coincides with the central axis of the parallel clamping plate electrodes that are mirror images of each other in the vibration direction, and is located inside the electrostatic sensor housing.

[0088] 7. The rectangular electrostatic induction electrode 4 can adjust its relative position with the parallel clamping plate electrodes that are mirror images of each other on the central axis where its induction surface / detection surface 4-1 is located according to the needs of electrostatic detection.

[0089] The size of the rectangular electrostatic charge sensing electrode can also be set according to the needs of electrostatic detection.

[0090] 8. Sinusoidal voltage is applied to the two outer rectangular electrode sheets 1, and the two inner rectangular electrode sheets 2 are connected to zero volts (i.e., "zero connection"). In this way, the piezoelectric ceramic sheet 3 in the middle can be driven to generate a longitudinal direction (referring to the detection direction of the external electrostatic voltage or field strength, that is, the central axis direction of the sensing surface / detection surface 4-1 of the electrostatic charge sensing electrode, see Figure 5 , Figure 6 The reciprocating motion of the electrostatic charge sensing electrode 4 in the x direction (i.e., forming a longitudinal wave vibration mode) eventually forms a standard sinusoidal oscillation capacitance between the electrostatic charge sensing electrode 4, and a standard sinusoidal signal is detected on the electrostatic charge sensing electrode 4.

[0091] 9. Compared with the structure and working mode of the existing vibration electrode vibration plate, the parallel clamping plate vibration electrode of the technical solution has almost no local deformation of the vibration electrode plate because the piezoelectric ceramic plate fully covers the vibration electrode plate, and only generates the overall vibration / motion of the vibration plate (comparison Figure 2-1 , 2-2 and Figure 5 , Figure 6 shown in; Figure 2-1 , Figure 2-2 In the prior art, a piezoelectric ceramic sheet is partially arranged on the inner surface of the vibrating electrode vibrating sheet, and the vibration / movement of the vibrating sheet occurs at the end of the vibrating sheet close to one end of the electrostatic charge induction electrode, and the vibration process is similar to the front end "vibration" mode of a tuning fork (also known as a transverse wave vibration mode), that is, the aforementioned vibrating electrode sheet produces its own local deformation; and, due to the influence of factors such as its material and structural shape, the mechanical vibration frequency of the front end of the vibrating electrode sheet cannot be completely consistent with the driving voltage frequency of the piezoelectric ceramic sheet; and from Figure 5 , Figure 6 It can be seen from the figure that the parallel clamping plate type vibration electrode of the present technical solution has almost no local deformation of the vibration electrode sheet because the piezoelectric ceramic sheet fully covers the vibration electrode sheet, and only generates the overall vibration / motion of the vibration sheet along the longitudinal axis direction (also known as longitudinal wave vibration), that is, Figure 5 , Figure 6 Its mechanical vibration frequency is consistent with its driving voltage frequency, that is, the vibration frequency is completely controlled by the driving voltage frequency; in this way, the driving voltage frequency can be adjusted according to the change of the static power source, so that the vibration frequency can better adapt to the on-site process changes and enhance the applicability to the on-site environment.

[0092] Best embodiment:

[0093] In order to verify the rationality, effectiveness and superiority of the above-mentioned parallel clamping plate electrodes A, A' (referred to as the vibration electrodes of the technical solution or the present vibration electrodes), a simulation comparison test is carried out on the structure of the existing static electricity detection vibration electrode (referred to as the existing vibration electrode) and the structure of the vibration electrode of the technical solution. The method flow and result analysis of the comparison test are as follows:

[0094] 1) See Figure 1 , Figure 3 , Figure 3-1 As shown, the structural models of the existing electrostatic detection vibration electrode and the vibration electrode of this technical solution are constructed respectively.

[0095] 2) Apply linear elastic and piezoelectric solid mechanics mathematical models to the above two types of vibration electrodes respectively:

[0096] Since the metal vibration plate belongs to micro vibration / motion (nano-micrometer level) in actual work, it conforms to the strain equation of linear elastic material in solid mechanics:

[0097]

[0098] S=S inel +S el , ε el =ε-ε inel

[0099] ε inel =ε0+ε th

[0100] S el =C:ε el

[0101] S inel =S0+S ext +S q

[0102]

[0103] C=C(E,ν)

[0104] In the above formula, C is the elastic tensor, a dimensionless number; E is Young's modulus, in Pa, and this technical solution uses the copper Young's modulus of 120e9Pa; ν is Poisson's ratio, a dimensionless number, and this technical solution uses the copper Poisson's ratio of 0.34; u is the material deformation displacement, in m; S is the stress tensor, in N / m 2 ; ρ is the material density, unit: kg / m 3 In this technical solution, the density of copper is 8960kg / m 3 ; F V is the external body force. In this technical solution, there is no additional force. Set F V= 0; ε is the total strain tensor, a dimensionless number; ε th is the thermal strain tensor. This technical solution ignores the thermal effect and assumes ε th =0;ε inel is the inelastic strain tensor; ε el is the elastic strain tensor; ε0 is the initial strain tensor. Since there is no displacement at the initial moment, ε0=0 is set.

[0105] The welding pins b' and b' in Figure 2 are respectively Figure 3 The outer side surface 1-1 of the metal rectangular electrode sheet 1 is fixed and constrained so that its displacement is zero, that is: u=0.

[0106] Due to the electrostatic charge sensing electrode e and Figure 3 The electrostatic charge sensing electrodes 4 in the circuit board are all soldered to the circuit board, so their displacement constraints are also set to zero, that is, u=0.

[0107] This technical solution uses PZT-5H piezoelectric ceramics, which conform to the following piezoelectric material solid mechanics and electrical equations:

[0108]

[0109]

[0110] S=S0+S el -E·e

[0111] ε el =ε-ε inel , ε inel =ε0+ε th

[0112]

[0113] S el =c:ε el , c=c(c E ), e=e(e ES )

[0114] D=D r +ε 0,vac ε rs E+e:ε el

[0115]

[0116] In the above formula: c E is the stress charge type elastic matrix, unit is Pa; s E is the strain charge type compliance matrix, unit 1 / Pa; e ES is the stress-charge coupling matrix, in C / m 2;d ET is the strain charge coupling matrix, unit C / N; ε rS is the stress charge type relative dielectric constant of the piezoelectric material, dimensionless; ε rT is the strain charge type relative dielectric constant of the piezoelectric material, dimensionless; ε 0,vac is the vacuum dielectric constant, ε 0,vac =8.854187817×10 -12 F / m; D is the total electric displacement of the piezoelectric material, unit C / m 2 ;D r is the residual electric displacement, in C / m 2 ; E is the electric field intensity, unit V / m; e is the piezoelectric strain tensor, dimensionless number; ρ V is the charge density, in C / m 3 .

[0117] The elastic matrix, coupling matrix and relative dielectric constant of the above materials can be found through relevant literature.

[0118] 3) Applying the electrostatic field mathematical model to piezoelectric ceramic structures:

[0119]

[0120] D=ε0E+P(E)+P e (S elast )

[0121]

[0122] P = ε0(ε rS -1)E

[0123] In the above formula: P is the polarization intensity, unit C / m 2 ; ε0 is the dielectric constant of vacuum, ε0=8.854187817×10 -12 F / m, unit F / m; ε rS is the relative dielectric constant of the piezoelectric material, dimensionless; V is the space potential, unit V; P e (S elast ) is the polarization caused by elastic strain, unit C / m 2 .

[0124] 4) A sinusoidal voltage, such as V=5×sin(2×π×f×t), is used to drive the piezoelectric ceramic piece 3 in the middle of the vibration electrode of the present technical solution and the piezoelectric ceramic piece c of the existing vibration electrode; wherein f is the voltage frequency, and f=450 (Hz).

[0125] For the existing vibrating electrode, the sinusoidal voltage is electrically connected to the lead c' in FIG. 2, and the vibrating plate d is connected to zero volts.

[0126] For the vibration electrode of the present technical solution, the sinusoidal voltage is electrically connected to the Figure 3 On the outer rectangular electrode sheet 1, the inner rectangular electrode sheet 2 can be connected to zero volt through a lead wire.

[0127] 5) Perform meshing including mapping and scanning operations on the overall vibration electrode structure.

[0128] 6) Execute simulation operation to obtain corresponding simulation results;

[0129] Select Figure 1 The center point o of the end surface of a vibrating piece facing the electrostatic charge sensing electrode e shown in FIG. 2 is used as the displacement analysis point of the conventional electrostatic detection electrode.

[0130] Select Figure 3-1 The center point o' of the end surface of an inner rectangular electrode sheet 2 facing the electrostatic charge sensing electrode 4 is used as the displacement analysis point of the vibration electrode of the present technical solution.

[0131] The time-varying characteristic curves of the displacement fields of the two are produced, see Figure 7 , Figure 8 , Fig. 9 , Fig.10 , Fig.11 , Fig.12 shown.

[0132] 7) Based on the simulation results, analyze and compare the time-varying characteristics of the displacement fields of different vibrating electrode structures, see Fig.13 , Figure 13-1 as well as Fig.14 as shown in .

[0133] from Fig.13 and Figure 13-1 It can be seen that the vibration electrode of the present technical solution achieves stable functional vibration after 5 cycles (about 0.01111s); in this way, the detection / detection signal of the static source will also enter a stable state; this will help the static voltage sensor to enter a stable working state more quickly and achieve stable detection of the static source.

[0134] 8) From Fig.14 It can be seen that the interfering displacement of the vibration electrode of the present technical solution is much smaller than that of the existing vibration electrode. Therefore, the detected interfering signal is also much smaller than that of the existing vibration electrode.

[0135] 9) See Fig.13 and Figure 13-1 As shown, the existing vibration electrodes cannot effectively form stable vibrations in a very long period (at least 22 periods, about 0.04889 s), which will lead to unstable functional detection signals and inability to accurately detect static electricity sources.

[0136] 10) Comparison Figure 2-1 , 2-2 and Figure 5 , Figure 6 , and combined with Fig.13 , Figure 13-1 As shown in the figure, compared with the vibration plate of the existing vibration electrode, the parallel clamping plate vibration electrode in the present technical solution, because the piezoelectric ceramic sheet 3 fully covers the internal rectangular electrode sheet 2, the internal rectangular electrode sheet 2 hardly produces its own local deformation, and only produces the overall vibration / movement of the internal rectangular electrode sheet 2, and its main deformation site is concentrated on the piezoelectric ceramic sheet 3; the mechanical vibration frequency of the internal rectangular electrode sheet 2 is consistent with the driving voltage frequency of the piezoelectric ceramic sheet (while the vibration electrode of the prior art is not consistent), that is, the vibration frequency is completely controlled by the driving voltage frequency; in this way, the driving voltage frequency can be adjusted according to the change of the static power source, so that the vibration frequency can better adapt to the on-site process changes and enhance the applicability to the on-site environment.

[0137] 11) According to Figure 7 , Figure 8 , Fig. 9 , Fig.10 , Fig.11 , Fig.12 The statistical simulation data are used to calculate the ratio of the interfering vibration displacement to the functional (main) vibration displacement of the existing electrostatic detection vibration electrode and the vibration electrode of the technical solution:

[0138] For existing vibrating electrodes, the maximum amplitude in each vibration direction is taken:

[0139]

[0140]

[0141] For the vibrating electrode of this technical solution, the maximum amplitude is taken in the non-main vibration direction, and the amplitude during stable vibration is taken in the main vibration direction:

[0142]

[0143] (negligible)

[0144] Therefore, it can be seen that the relative interference of the vibration of the vibration electrode in the non-main vibration direction on the vibration in the main vibration direction in the present technical solution is significantly smaller than that of the existing vibration electrode.

[0145] In addition, for existing vibrating electrodes, the displacement in the functional (main) vibration direction mainly occurs in Figure 2-1 , Figure 2-2In the y-axis direction shown in , relative to the body of the vibration plate of the existing vibration electrode, the front end of the vibration plate performs a "lateral swing" vibration (abbreviated as transverse wave vibration).

[0146] For the vibration electrode of the present technical solution, the displacement in the functional (main) vibration direction only generates the overall vibration / movement of the internal rectangular electrode piece, which belongs to the longitudinal wave vibration mode.

[0147] The main deformation site is concentrated on the piezoelectric ceramic sheet 3; the mechanical vibration frequency of the internal rectangular electrode sheet 2 is consistent with the driving voltage frequency of the piezoelectric ceramic sheet, that is, the vibration frequency is completely controlled by the driving voltage frequency.

[0148] In summary, in the verification stage of the present technical solution, the structural models of the existing electrostatic detection vibration electrode and the vibration electrode of the present technical solution are constructed respectively; the linear elastic and piezoelectric solid mechanics mathematical models are applied to the overall vibration electrode; the electrostatic field mathematical model is applied to the piezoelectric ceramic structure (piece), and the overall vibration electrode structure is meshed with mapping and scanning operations; simulation operations are performed to obtain corresponding simulation results; the time-varying characteristics of the displacement fields of different vibration electrode structures are analyzed and compared; finally, the superiority of the vibration structure described in the present technical solution is determined by the time period for entering the stable state and the ratio of the interfering vibration displacement to the functional (main) vibration displacement.

[0149] The technical solution of the utility model adopts a mirror-symmetrical composite layered parallel clamping plate type vibration electrode structure, and adopts a "surface" type fixing method for the parallel clamping plate type vibration electrode. Its functional (main) vibration direction is parallel to the length direction of the vibration electrode, forming a longitudinal wave type vibration mode, and the piezoelectric ceramic sheet fully covers the vibration electrode sheet; in this way, the time period for it to enter a stable state is shortened; it can effectively reduce interfering vibrations and the stray capacitance signals caused by them, making the detection results more accurate and more stable.

[0150] The utility model can be widely used in the field of designing and manufacturing vibration detection electrodes in static voltage sensors.

Claims

1. A parallel clamp-plate-shaped vibrating electrode for electrostatic detection, comprising a vibrating electrode for electrostatic detection, characterized in that: The vibrating electrode comprises a pair of parallel clamping plate electrodes arranged in mirror images of each other; Each parallel clamping plate electrode is composed of two mutually parallel rectangular electrode sheets, namely an outer electrode sheet and an inner electrode sheet; A piezoelectric ceramic sheet is arranged between the external electrode sheet and the internal electrode sheet; The external electrode sheet, the internal electrode sheet and the piezoelectric ceramic sheet are fixedly connected as a whole to form a parallel clamping plate electrode with a layered composite structure; Each of the parallel clamping plate electrodes is fixed on the circuit board through an external electrode sheet; A rectangular electrostatic induction electrode is arranged at one end of the parallel clamping plate electrode; The side of the rectangular electrostatic induction electrode facing away from the parallel clamping plate electrode group is the sensing surface / detection surface of the electrostatic charge sensing electrode; The rectangular electrostatic induction electrodes are independently fixed on the circuit board; The external electrode sheet is electrically connected to the circuit board that fixes the vibration electrode; The internal electrode sheet is connected to a zero volt voltage.

2. The parallel clamp-plate-shaped vibrating electrode for electrostatic detection according to claim 1, characterized in that The rectangular electrode sheet is a metallic rectangular electrode sheet.

3. The parallel clamp-plate-shaped vibrating electrode for electrostatic detection according to claim 1, characterized in that The pair of parallel clamping plate electrodes are arranged in mirror image with each other along the length direction.

4. The parallel clamp-plate-shaped vibrating electrode for electrostatic detection according to claim 1, characterized in that The planes where the electrode sheets inside the pair of parallel clamping plate electrodes are located are arranged facing each other and are mirror images of each other.

5. The parallel clamp-plate-shaped vibrating electrode for electrostatic detection according to claim 1, characterized in that The external electrode sheet and the internal electrode sheet have the same shape and are arranged in parallel.

6. The parallel clamp-plate-shaped vibrating electrode for electrostatic detection according to claim 1, characterized in that The piezoelectric ceramic sheet has the same shape as the internal electrode sheet; the piezoelectric ceramic sheet completely covers the internal electrode sheet; the mechanical vibration frequency of the internal electrode sheet is consistent with the driving voltage frequency of the piezoelectric ceramic sheet.

7. The parallel clamp-plate-shaped vibrating electrode for static electricity detection according to claim 1, characterized in that Each of the parallel clamping plate electrodes is fixed on the circuit board through the outer surface of its external electrode sheet, forming a "surface contact" type fixing structure.

8. The parallel clamp-plate-shaped vibrating electrode for static electricity detection according to claim 1, characterized in that A rectangular electrostatic induction electrode is arranged in front of the parallel clamping plate electrodes that are mirror images of each other in the vibration direction. The central axis of the sensing surface / detection surface of this electrostatic charge induction electrode coincides with the central axis of the parallel clamping plate electrodes that are mirror images of each other in the vibration direction, and the electrostatic induction electrode is located inside the electrostatic sensor housing.

9. The parallel clamp-plate-shaped vibrating electrode for static electricity detection according to claim 1, characterized in that The functional vibration direction / main vibration direction of the parallel plate electrodes is parallel to or coincides with the length direction of the parallel plate electrodes, forming a longitudinal wave vibration mode.

10. The parallel clamp-plate-shaped vibrating electrode for static electricity detection according to claim 1, characterized in that The parallel clamp-shaped vibration electrode electrically connects the sinusoidal voltage to the external electrode sheet through the circuit board that fixes the vibration electrode, and connects the internal electrode sheet to zero volt voltage through the lead wire; In this way, the piezoelectric ceramic sheet located between the external electrode sheet and the internal electrode sheet is driven to generate a reciprocating motion along the length direction of the parallel clamp-shaped vibration electrode or the piezoelectric ceramic sheet, forming a longitudinal wave vibration mode, and finally forming a standard sinusoidal oscillation capacitance with the electrostatic charge sensing electrode, and a standard sinusoidal signal is detected on the electrostatic charge sensing electrode.

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