quartz crystal sensor

Abstract

The application relates to a quartz crystal sensor. The quartz crystal sensor comprises a vibration excitation device, a quartz crystal device and a detection circuit, wherein the vibration excitation device is used to generate lateral vibration and normal vibration under the excitation of an excitation signal; the quartz crystal device comprises a first electrode, a second electrode, a wafer and a probe, the probe is used to generate lateral vibration and normal vibration under the driving of the vibration excitation device, and contact an object to be measured to generate lateral force and normal force in the process of the lateral vibration and the normal vibration, the first electrode is used to output a first electric signal when the wafer is deformed under the action of the lateral force, and the second electrode is used to output a second electric signal when the wafer is deformed under the action of the normal force; and the detection circuit is used to output a detection signal of the lateral force and the normal force according to the first electric signal and the second electric signal. The quartz crystal sensor in the application can measure vibration modal signals in multiple dimensions and is suitable for multiple scenes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensors, in particular to a quartz crystal sensor. BACKGROUND

[0002] The quartz crystal has piezoelectric effect characteristics of converting electrical energy and mechanical energy, and can be used to measure physical quantities such as temperature, mass, frequency and force, so it is widely used in electronic products such as sensors.

[0003] The quartz crystal sensor in the prior art can only measure the vibration mode signal of a single dimension, that is, either the transverse vibration mode signal or the normal vibration mode signal. However, in the measurement process of the friction coefficient, both the transverse friction force mode signal and the normal pressure mode signal need to be measured. Therefore, the quartz crystal sensor in the prior art cannot measure the vibration mode signal of multiple dimensions, thereby greatly limiting the applicable scenarios. SUMMARY

[0004] Therefore, it is necessary to provide a quartz crystal sensor capable of measuring the vibration mode signal of multiple dimensions and applicable to multiple scenarios.

[0005] In a first aspect, the present application provides a quartz crystal sensor. The quartz crystal sensor comprises a vibration excitation device, a quartz crystal device and a detection circuit, and the quartz crystal device is connected with the vibration excitation device and the detection circuit respectively; wherein the vibration excitation device is used to generate transverse vibration and normal vibration under the excitation of an excitation signal; the quartz crystal device comprises a first electrode, a second electrode, a wafer and a probe, the first electrode, the second electrode and the probe are connected with the wafer, the probe is used to vibrate transversely and normally under the driving of the vibration excitation device, and contact an object to be measured to generate a transverse force and a normal force in the process of transverse vibration and normal vibration, the first electrode is used to output a first electric signal when the wafer is deformed under the action of the transverse force, and the second electrode is used to output a second electric signal when the wafer is deformed under the action of the normal force; the detection circuit is used to output a detection signal of the transverse force and the normal force according to the first electric signal and the second electric signal.

[0006] In one embodiment, the wafer is in the shape of a cuboid or a cube; the quartz crystal device comprises four second electrodes corresponding to the four sides of the wafer respectively, each second electrode is connected with the corresponding side of the wafer; the quartz crystal device comprises four first electrodes corresponding to the four edges of the wafer respectively, each first electrode is connected with the two sides of the wafer on both sides of the corresponding edge.

[0007] In one of the embodiments, the vibration excitation device comprises an excitation electrode, a shear ceramic sheet and a normal ceramic sheet, which are stacked together; the excitation electrode is configured to receive an excitation signal; the shear ceramic sheet is configured to generate a transverse vibration under the excitation of the excitation signal; and the normal ceramic sheet is configured to generate a normal vibration under the excitation of the excitation signal.

[0008] In one of the embodiments, the excitation electrode comprises a first excitation electrode, a second excitation electrode and a grounding electrode; the first excitation electrode is configured to receive the electrical signal output by the first electrode and the second electrode as a first excitation signal; the second excitation electrode is configured to receive a second excitation signal output by a phase-locked amplifier of the external device; and the grounding electrode is configured to be grounded.

[0009] In one of the embodiments, the vibration excitation device further comprises a first sapphire sheet, a second sapphire sheet and a third sapphire sheet, the shear ceramic sheet comprises a first shear ceramic sheet and a second shear ceramic sheet, the normal ceramic sheet comprises a first normal ceramic sheet and a second normal ceramic sheet, the first excitation electrode comprises a first sub-excitation electrode and a second sub-excitation electrode, the second excitation electrode comprises a third sub-excitation electrode and a fourth sub-excitation electrode, and the grounding electrode comprises a first grounding electrode and a second grounding electrode; the first sapphire sheet, the first sub-excitation electrode, the first shear ceramic sheet, the first grounding electrode, the second shear ceramic sheet, the third sub-excitation electrode, the second sapphire sheet, the second sub-excitation electrode, the first normal ceramic sheet, the second grounding electrode, the second normal ceramic sheet, the fourth sub-excitation electrode and the third sapphire sheet are stacked together.

[0010] In one of the embodiments, the quartz crystal sensor further comprises an amplification circuit, an input end of the amplification circuit is connected with the first electrode and the second electrode respectively, and an output end of the amplification circuit is connected with the first excitation electrode.

[0011] In one of the embodiments, the amplification circuit comprises a cross-group amplification circuit, a gain circuit and a phase-shifting circuit; an input end of the cross-group amplification circuit is connected with the first electrode and the second electrode respectively, an output end of the cross-group amplification circuit is connected with an input end of the gain circuit, an output end of the gain circuit is connected with an input end of the phase-shifting circuit, and an output end of the phase-shifting circuit is connected with the first excitation electrode; wherein the cross-group amplification circuit is configured to amplify the first electrical signal and the second electrical signal, and the gain circuit and the phase-shifting circuit are respectively configured to adjust the amplitude and the phase of the first electrical signal and the second electrical signal.

[0012] In one of the embodiments, the cross-group amplification circuit comprises a first amplifier, a first resistor and a second resistor; a first input end of the first amplifier is connected with the first resistor and grounded; a second input end of the first amplifier is connected with the first electrode and the second electrode respectively; an output end of the first amplifier is connected with an input end of the gain circuit; and the second resistor is connected between the second input end of the first amplifier and the output end of the first amplifier.

[0013] In one of the embodiments, the gain circuit comprises a second amplifier, a third resistor and a first slide rheostat; a first input end of the second amplifier is grounded; a second input end of the second amplifier is connected with the output end of the group amplification circuit through the third resistor; an output end of the second amplifier is connected with the input end of the phase shift circuit; the first slide rheostat is connected between the second input end of the second amplifier and the output end of the second amplifier.

[0014] In one of the embodiments, the phase shift circuit comprises a third amplifier, a capacitor, a fourth resistor, a fifth resistor and a second slide rheostat; a first input end of the third amplifier is connected with the output end of the gain circuit through the second slide rheostat, and the first input end of the third amplifier is connected with the capacitor and grounded; a second input end of the third amplifier is connected with the output end of the gain circuit through the fourth resistor, and the second input end of the third amplifier is connected with the output end of the third amplifier through the fifth resistor; an output end of the third amplifier is connected with the first excitation electrode.

[0015] In one of the embodiments, the quartz crystal sensor further comprises a ceramic boss, a ceramic gasket, a threaded sheet and a base; the quartz crystal device is connected with the vibration excitation device through the ceramic boss, the ceramic gasket and the threaded sheet; the base is connected with the vibration excitation device.

[0016] In one of the embodiments, the quartz crystal sensor further comprises a sample stage for placing the object to be measured; the sample stage is arranged at a position with a threshold distance from the probe.

[0017] The above quartz crystal sensor comprises a vibration excitation device, a quartz crystal device and a detection circuit, the quartz crystal device is connected with the vibration excitation device and the detection circuit respectively, and the quartz crystal device comprises a first electrode, a second electrode, a wafer and a probe, the first electrode, the second electrode and the probe are all connected with the wafer. Wherein, the vibration excitation device generates lateral vibration and normal vibration under the excitation of the excitation signal, drives the probe to generate lateral vibration and normal vibration, so that the probe contacts the object to be measured to generate lateral force and normal force in the process of lateral vibration and normal vibration, so that the first electrode outputs a first electric signal when the wafer deforms under the action of the lateral force, and the second electrode outputs a second electric signal when the wafer deforms under the action of the normal force, so as to output a detection signal of the lateral force and the normal force by the detection circuit according to the first electric signal and the second electric signal, that is, to output the lateral vibration modal signal and the normal vibration modal signal, so as to realize the purpose of measuring multiple dimensional vibration modal signals, so that the quartz crystal sensor in the application can be applied to multiple scenes. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A structural diagram of a quartz crystal sensor in one of the embodiments;

[0019] Figure 2 Five views of a quartz crystal oscillator device in one embodiment;

[0020] Figure 3 A cross-sectional view of a quartz crystal oscillator device in one embodiment;

[0021] Figure 4 A block diagram of a vibration excitation device in one embodiment;

[0022] Figure 5 A circuit diagram of an amplification circuit in one embodiment;

[0023] Figure 6 A graph of frequency offset versus amplitude in one embodiment;

[0024] Figure 7 A block diagram of another quartz crystal oscillator sensor in one embodiment. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0026] The main functional material of the quartz crystal oscillator is silicon dioxide, which has stable physical and chemical properties, good optical and piezoelectric properties, and is applied to the detection of various physical quantities such as temperature, mass, frequency and force. Moreover, according to the cut type of the quartz crystal oscillator, the resonator can be set to work in different characteristic frequency ranges, therefore, the quartz crystal oscillator involves a wide range of industries, the upstream industry mainly includes crystal, base, packaging material and other material manufacturing and precision machinery research industries, and the downstream application field is electronic products, including communication network, mobile terminal, Internet of Things, automotive electronics, smart home and household appliances, etc.

[0027] The quartz tuning fork is one of the most widely used applications of the quartz crystal oscillator. The most important role is to provide a watch reference resonance frequency, i.e. 32768 Hz. Due to the inverse piezoelectric effect, different regions of the tuning fork arm are stressed, which will cause charge accumulation. By measuring the charge, the stress on the tuning fork can be obtained. This is widely used in the latest qPlus atomic force microscope, which can be used to measure the interaction force between atoms and molecules, the structure of water molecules on the crystal surface, and the type of material elements. The existing commercial quartz tuning fork sensor, i.e. quartz crystal oscillator sensor, can only obtain a single-dimensional vibration mode signal according to the electrode distribution of the tuning fork arm. However, in some MEMS (Micro-Electro-Mechanical System) sensing and measurement fields, multiple-dimensional force signals are required, for example, in the measurement process of the friction coefficient, both the lateral friction force mode signal and the normal pressure mode signal need to be measured. Therefore, the application scenarios of the quartz crystal oscillator sensor in the traditional technology are greatly limited.

[0028] In addition, the quality factor Q value is an important electrical parameter of the quartz crystal oscillator, which is closely related to the frequency stability of the crystal oscillator. The larger the Q value, the smaller the quartz crystal oscillator resistance, the smaller the loss, the smaller the required excitation power, the easier to start, the better the frequency stability, i.e. the better the crystal oscillator stability. The Q value of the quartz crystal oscillator in the traditional technology is not adjustable, which makes the detection efficiency and detection precision of the quartz crystal oscillator sensor low.

[0029] Based on the above problems, it is necessary to propose effective technical means to solve the problems of limited application scenarios and unadjustable Q value of the quartz crystal oscillator sensor in the traditional technology.

[0030] In one embodiment, as Figure 1As shown, a structural diagram of a quartz crystal sensor is provided, which includes a vibration excitation device 100, a quartz crystal device 200 and a detection circuit 300, the quartz crystal device 200 is connected with the vibration excitation device 100 and the detection circuit 300 respectively; wherein the vibration excitation device 100 is used to generate lateral vibration and normal vibration under the excitation of an excitation signal; the quartz crystal device 200 includes a first electrode 201, a second electrode 202, a wafer 203 and a probe 204, the first electrode 201, the second electrode 202 and the probe 204 are all connected with the wafer 203, the probe 204 is used to generate lateral vibration and normal vibration under the driving of the vibration excitation device 100, and contact a to-be-measured object to generate lateral force and normal force in the process of lateral vibration and normal vibration, the first electrode 201 is used to output a first electric signal when the wafer 203 generates deformation under the action of the lateral force, the second electrode 202 is used to output a second electric signal when the wafer 203 generates deformation under the action of the normal force; the detection circuit 300 is used to output a detection signal of the lateral force and the normal force according to the first electric signal and the second electric signal.

[0031] The connection mode of the vibration excitation device 100 and the wafer 203 can be connected with the wafer 203 through a connecting piece, or directly connected with the wafer 203. The vibration excitation device 100 can be a piezoelectric ceramic module composed of multiple ceramic pieces, under the excitation of an excitation signal, some ceramic pieces can generate lateral vibration, and the other ceramic pieces can generate normal vibration, thereby driving the wafer 203 to generate lateral vibration and normal vibration.

[0032] The probe 204 can be a cleaning-free needle with a high-performance spring, gold-plated surface and A+ material. One end of the probe 204 is coated with insulating glue, which can be directly connected with the wafer 203, or connected with the wafer 203 through the first electrode 201 or the second electrode 202, and the other end of the probe 204 is spaced apart from the to-be-measured object by about 1nm-10nm. When the wafer 203 is driven by the vibration excitation device 100 to generate lateral vibration and normal vibration, since the probe 204 is directly or indirectly connected with the wafer 203, the probe 204 will also generate lateral vibration and normal vibration, when the probe 204 generates normal vibration, it will contact the to-be-measured object, so that the probe 204 will be subjected to the pressure of the to-be-measured object, that is, the normal force; when the probe 204 generates lateral vibration while generating normal vibration, the probe 204 will also be subjected to the friction force of the to-be-measured object, that is, the lateral force.

[0033] The wafer 203 can be a cube or a cuboid cut from a crystal of silica material. When the probe 204 is subjected to the lateral force and the normal force, since the probe 204 is directly or indirectly connected with the wafer 203, the wafer 203 will also be subjected to the lateral force and the normal force, and the wafer 203 will generate deformation under the action of the lateral force and the normal force.

[0034] The first electrode 201 and the second electrode 202 can be electrodes coated with metal on the surface, such as silver electrodes. The first ends of the first electrode 201 and the second electrode 202 are connected to the wafer 203 by coating with insulating glue, and the second ends of the first electrode 201 and the second electrode 202 are exposed and not connected to the wafer 203, so that the first electrode 201 and the second electrode 202 can be regarded as long arms of the quartz crystal resonator device 200. The first electrode 201 and the second electrode 202 are connected to the wafer 203 in a special way. When the wafer 203 deforms under the action of the lateral force, the first electrode 201 will accumulate electric charges, that is, the first electric signal is generated; when the wafer 203 deforms under the action of the normal force, the second electrode 202 will accumulate electric charges, that is, the second electric signal is generated.

[0035] The connection mode of the detection circuit 300 and the wafer 203 can be connected to the wafer 203 through an amplifying circuit, or can be directly connected to the wafer 203. Specifically, the detection circuit 300 is directly or indirectly connected to the first electrode 201, used for collecting and processing the electric charges accumulated on the first electrode 201, to obtain the detection signal of the lateral force, that is, the lateral vibration modal signal. At the same time, the detection circuit 300 is also directly or indirectly connected to the second electrode 202, used for collecting and processing the electric charges accumulated on the second electrode 202, to obtain the detection signal of the normal force, that is, the normal vibration modal signal.

[0036] In summary, the quartz crystal resonator sensor includes the vibration excitation device 100, the quartz crystal resonator device 200 and the detection circuit 300. The quartz crystal resonator device 200 is connected to the vibration excitation device 100 and the detection circuit 300, and the quartz crystal resonator device 200 includes the first electrode 201, the second electrode 202, the wafer 203 and the probe 204. The first electrode 201, the second electrode 202 and the probe 204 are connected to the wafer 203. The vibration excitation device 100 generates lateral vibration and normal vibration under the excitation of the excitation signal, drives the probe 204 to perform lateral vibration and normal vibration, so that the probe 204 contacts the object to be measured to generate lateral force and normal force in the process of lateral vibration and normal vibration. When the wafer 203 deforms under the action of the lateral force, the first electrode 201 outputs the first electric signal, and when the wafer 203 deforms under the action of the normal force, the second electrode 202 outputs the second electric signal. Therefore, the detection circuit 300 outputs the detection signals of the lateral force and the normal force according to the first electric signal and the second electric signal, that is, outputs the lateral vibration modal signal and the normal vibration modal signal, so as to achieve the purpose of measuring vibration modal signals in multiple dimensions. Therefore, the quartz crystal resonator sensor in the application can be applied to multiple scenes.

[0037] In one of the embodiments, as shown in Figure 2The diagram shows a five-view drawing of a quartz crystal oscillator device. The crystal 203 is rectangular or cubic in shape. The quartz crystal oscillator device 200 includes four second electrodes 202 corresponding to the four sides of the crystal 203, each second electrode 202 being connected to the corresponding side of the crystal 203. The quartz crystal oscillator device 200 also includes four first electrodes 201 corresponding to the four edges of the crystal 203, each first electrode 201 being connected to the two sides of the crystal 203 on either side of the corresponding edge.

[0038] The wafer 203 comprises six faces, which can be named top, bottom, front, back, left, and right. The four sides of the wafer 203 can be any four consecutive faces, such as the top, front, bottom, and right sides, denoted by c, a, b, and d respectively. The four edges of the wafer 203 can be edges corresponding to any two adjacent sides, such as the edges corresponding to sides c and a, sides a and b, sides b and d, and sides d and c.

[0039] like Figure 3 The diagram shows a cross-sectional view of a quartz crystal oscillator device. Four first electrodes 201, denoted by K1, K2, L1, and L2, are connected to two adjacent side surfaces on each of the four corresponding edges; that is, two adjacent side surfaces share one first electrode 201. Four second electrodes 202, denoted by N1, N2, M1, and M2, are connected to the four corresponding side surfaces; that is, each side surface has its own unique second electrode 202.

[0040] When the wafer 203 is subjected to the lateral force of the probe 204, the wafer 203 deforms, and charges accumulate on the four first electrodes 201, K1, K2, L1 and L2. Among them, K1 and K2 accumulate equal amounts of charges of the same sign, and L1 and L2 also accumulate equal amounts of charges of the same sign, but their polarities are opposite to those of K1 and K2.

[0041] When the wafer 203 is subjected to the normal force of the probe 204, the wafer 203 deforms, and charges accumulate on the four second electrodes 201, N1, N2, M1 and M2. Among them, N1 and N2 accumulate equal amounts of charges of the same sign, and M1 and M2 also accumulate equal amounts of charges of the same sign, but their polarities are opposite to those of N1 and N2.

[0042] The detection circuit 300 is directly or indirectly connected with the four first electrodes 201 and the four second electrodes 202 respectively, and collects the charges on K1, K2, L1, L2, N1, N2, M1 and M2 in real time. At the same time, the charges with polarity corresponding to K1 and K2 are added to obtain a first charge value, the charges with polarity corresponding to L1 and L2 are added to obtain a second charge value, and then the first charge value is subtracted from the second charge value to obtain a detection signal of the lateral force. The charges with polarity corresponding to N1 and N2 are added to obtain a third charge value, the charges with polarity corresponding to M1 and M2 are added to obtain a fourth charge value, and then the third charge value is subtracted from the fourth charge value to obtain a detection signal of the normal force.

[0043] In the embodiment, the four first electrodes 201 are arranged on the four edges of the wafer 203, so that the first signal can be output when the wafer 203 is deformed by the lateral force. The four second electrodes 202 are arranged on the four sides of the wafer 203, so that the second signal can be output when the wafer 203 is deformed by the normal force, so as to achieve the purpose that the quartz crystal oscillator sensor can measure multi-dimensional vibration modal signals.

[0044] In one of the embodiments, as shown in Figure 4 A structural diagram of a vibration excitation device is provided. The vibration excitation device 100 includes an excitation electrode, a shear ceramic sheet and a normal ceramic sheet, which are arranged in a stack, and wherein:

[0045] (1) The excitation electrode

[0046] The excitation electrode is used to receive an excitation signal. Specifically, the excitation electrode includes a first excitation electrode, a second excitation electrode and a ground electrode.

[0047] The first excitation electrode includes a first sub-excitation electrode 411 and a second sub-excitation electrode 412, which are used to receive the electrical signals output by the first electrode 201 and the second electrode 202 as a first excitation signal. That is, the first electrical signal output by the first electrode 201 and the second electrical signal output by the second electrode 202 will also be input to the first sub-excitation electrode 411 and the second sub-excitation electrode 412 as the first excitation signal.

[0048] The second excitation electrode includes a third sub-excitation electrode 413 and a fourth sub-excitation electrode 414, which are used to receive a second excitation signal output by a phase-locked amplifier of an external device.

[0049] The ground electrode includes a first ground electrode 415 and a second ground electrode 416, which are used for grounding.

[0050] The first sub-excitation electrode 411, the second sub-excitation electrode 412, the third sub-excitation electrode 413, and the fourth sub-excitation electrode 414, the first grounding electrode 415, and the second grounding electrode 416 are all metal materials, for example, pure copper materials.

[0051] (2) Shear ceramic sheet

[0052] The shear ceramic sheet is used to generate transverse vibration under the excitation of an excitation signal, and the polarization direction thereof is indicated by an arrow in Figure 4 . Specifically, the shear ceramic sheet includes a first shear ceramic sheet 421 and a second shear ceramic sheet 422.

[0053] The first shear ceramic sheet 421 generates transverse vibration under the reception of a first excitation signal at the first sub-excitation electrode 411.

[0054] The second shear ceramic sheet 422 generates transverse vibration under the reception of a second excitation signal at the third sub-excitation electrode 413.

[0055] (3) Normal ceramic sheet

[0056] The normal ceramic sheet is used to generate normal vibration under the excitation of an excitation signal, and the polarization direction thereof is indicated by an arrow in Figure 4 . Specifically, the normal ceramic sheet includes a first normal ceramic sheet 431 and a second normal ceramic sheet 432.

[0057] The first normal ceramic sheet 431 generates normal vibration under the reception of a first excitation signal at the second sub-excitation electrode 412.

[0058] The second normal ceramic sheet 432 generates normal vibration under the reception of a second excitation signal at the fourth sub-excitation electrode 414.

[0059] In addition, the vibration excitation device 100 further includes a first sapphire sheet 441, a second sapphire sheet 442, and a third sapphire sheet 443. The first sapphire sheet 441, the first sub-excitation electrode 411, the first shear ceramic sheet 421, the first grounding electrode 415, the second shear ceramic sheet 422, the third sub-excitation electrode 413, the second sapphire sheet 442, the second sub-excitation electrode 412, the first normal ceramic sheet 431, the second grounding electrode 416, the second normal ceramic sheet 432, the fourth sub-excitation electrode 414, and the third sapphire sheet 443 are stacked, specifically, stacked from top to bottom.

[0060] The sapphire sheet is used for insulation of the excitation signal, specifically, the first sapphire sheet 441 is used for insulation of the first excitation signal, the second sapphire sheet 442 is used for insulation of the first excitation signal and the second excitation signal, and the third sapphire sheet 443 is used for insulation of the second excitation signal.

[0061] In this embodiment, the first sub-excitation electrode 411 and the second sub-excitation electrode 412 are used to receive the electrical signals output by the first electrode 201 and the second electrode 202 as the first excitation signal. The third sub-excitation electrode 413 and the fourth sub-excitation electrode 414 are used to receive the second excitation signal output by the lock-in amplifier of the external device. That is, the excitation signal that causes the vibration excitation device 100 to vibrate is a superposition of two excitation signals: one is the first electrical signal output by the first electrode 201 and the second electrical signal output by the second electrode 202, and the other is the excitation signal output by the lock-in amplifier. Compared with conventional technology, this application outputs the electrical signals output by the electrodes to the vibration excitation device 100 again to cause the crystal to vibrate, thereby reducing the output of the excitation signal from the external device and thus reducing the cost of the quartz crystal sensor.

[0062] In one embodiment, such as Figure 5 The diagram shows a circuit diagram of an amplifier circuit. The quartz crystal oscillator sensor also includes an amplifier circuit 500. The input terminal of the amplifier circuit 500 is connected to the first electrode 201 and the second electrode 202, respectively, and the output terminal of the amplifier circuit 500 is connected to the first excitation electrode. Specifically, the amplifier circuit 500 includes a cross-group amplifier circuit 501, a gain circuit 502, and a phase-shifting circuit 503. The input terminal of the cross-group amplifier circuit 501 is connected to the first electrode 201 and the second electrode 202, respectively. The output terminal of the cross-group amplifier circuit 501 is connected to the input terminal of the gain circuit 502. The output terminal of the gain circuit 502 is connected to the input terminal of the phase-shifting circuit 503. The output terminal of the phase-shifting circuit 503 is connected to the first excitation electrode, wherein:

[0063] (1) Cross-group amplifier circuit 501

[0064] The cross-group amplifier circuit 501 is used to amplify the first electrical signal and the second electrical signal. Specifically, the cross-group amplifier circuit includes a first amplifier A1, a first resistor R1, and a second resistor R2; the first input terminal of the first amplifier A1 is connected to the first resistor R1 and grounded; the second input terminal of the first amplifier A1 is connected to the first electrode 201 and the second electrode 202 respectively; the output terminal of the first amplifier A1 is connected to the input terminal of the gain circuit 502; and the second resistor R2 is connected between the second input terminal and the output terminal of the first amplifier A1.

[0065] Among them, the first resistor R1 and the second resistor R2 can be selected with a resistance of 20GΩ. The cross-group amplifier circuit 501 can amplify the first electrical signal output from the first electrode 201 and the second electrical signal output from the second electrode 202 into millivolt-level voltage signals, respectively.

[0066] (2) Gain circuit 502

[0067] The gain circuit 502 is used to adjust the amplitude of the first electric signal and the second electric signal. Specifically, the gain circuit 502 comprises a second amplifier A2, a third resistor R3 and a first slide rheostat R11; the first input end of the second amplifier A2 is grounded; the second input end of the second amplifier A2 is connected with the output end of the cross-group amplification circuit 501 through the third resistor R3; the output end of the second amplifier A2 is connected with the input end of the phase shift circuit 503; and the first slide rheostat R11 is connected between the second input end of the second amplifier A2 and the output end of the second amplifier A2.

[0068] Among them, the third resistor R3 with a resistance of 10kΩ, the first slide rheostat R11 with a maximum resistance of 500Ω can be selected, and the first slide rheostat R11 can be used to adjust the amplitude of the first electric signal and the second electric signal, so as to achieve the purpose of adjusting the quality factor Q value of the quartz crystal device 200, and further improve the detection efficiency and detection precision of the quartz crystal sensor.

[0069] (3) Phase shift circuit 503

[0070] The phase shift circuit 503 is used to adjust the phase of the first electric signal and the second electric signal. Specifically, the phase shift circuit 503 comprises a third amplifier A3, a capacitor C1, a fourth resistor R4, a fifth resistor R5 and a second slide rheostat R22; the first input end of the third amplifier A3 is connected with the output end of the gain circuit 502 through the second slide rheostat R22, and the first input end of the third amplifier A3 is connected with the capacitor C1 and grounded; the second input end of the third amplifier A3 is connected with the output end of the gain circuit 502 through the fourth resistor R4, and the second input end of the third amplifier A3 is connected with the output end of the third amplifier A3 through the fifth resistor R5; the output end of the third amplifier A3 is connected with the first excitation electrode, that is, connected with the first sub excitation electrode 411 and the second sub excitation electrode 412 respectively.

[0071] Among them, the capacitor C1 with a capacity of 1nF, the fourth resistor R4 and the fifth resistor R5 with a resistance of 6.2kΩ, and the second slide rheostat R22 with a maximum resistance of 10kΩ can be selected, and the second slide rheostat R22 can be used to adjust the phase of the first electric signal and the second electric signal, so as to achieve the purpose of adjusting the quality factor Q value of the quartz crystal device 200, and further improve the detection efficiency and detection precision of the quartz crystal sensor.

[0072] In this embodiment, the first slide rheostat R11 and the second slide rheostat R22 are adjusted, so that the first electric signal and the second electric signal of the adjusted amplification circuit 500 are input as the first excitation signal and the second excitation signal to the first sub excitation electrode 411 and the second sub excitation electrode 412 in the vibration excitation device 100, so that the first shear ceramic piece 421 performs horizontal vibration and the first normal ceramic piece 431 performs normal vibration, to drive the quartz crystal unit 200 to vibrate, at this time, the Q value of the quartz crystal unit 200 is obviously improved.

[0073] In an ideal state, as shown in Figure 6 , a frequency offset-amplitude relationship curve is provided, the curve with larger amplitude at the frequency offset of 0 is the frequency offset-amplitude relationship curve before the Q value adjustment, and the curve with smaller amplitude at the frequency offset of 0 is the frequency offset-amplitude relationship curve after the Q value adjustment. After the Q value adjustment of the amplification circuit 500, the Q value of the quartz crystal unit 200 can be improved from the original 4000 to 260000.

[0074] In addition, the detection circuit 300 can be connected with the first electrode 201 and the second electrode 202 through the amplification circuit 500, specifically, the input end of the detection circuit 300 is connected with the output end of the amplification circuit 500. After the first electric signal output by the first electrode 201 and the second electric signal output by the second electrode 202 are amplified by the amplification circuit, the first electric signal and the second electric signal after the amplification are further processed by the detection circuit 300, and the obtained horizontal force detection signal and normal force detection signal are more obvious.

[0075] In one of the embodiments, as shown in Figure 7 , another structure diagram of the quartz crystal sensor is provided, the quartz crystal sensor further comprises a ceramic boss 600, a ceramic gasket 700, a threaded piece 800 and a base 900; the quartz crystal unit 200 is connected with the vibration excitation device 100 through the ceramic boss 600, the ceramic gasket 700 and the threaded piece 800; the base 900 is connected with the vibration excitation device 100. The quartz crystal sensor further comprises a sample stage 1000 for placing the object to be measured; the sample stage 1000 is arranged at a position with a threshold distance from the probe 204.

[0076] The shape and material of the sample stage 1000 can be set as needed, which is not limited here. The sample stage 1000 is generally arranged at a distance of about 1-10 nm from the probe (for a clearer illustration, the distance is enlarged in the figure).

[0077] The probe 204 is arranged on any first electrode 201 or any second electrode 202.

[0078] The wafer 203 is arranged on the upper edge of the ceramic boss 600, specifically, insulating glue is applied on the wafer 203, and then the wafer 203 is adhered to the upper edge of the ceramic boss 600.

[0079] The ceramic boss 600, the ceramic gasket 700 and the threaded sheet 800 are arranged in sequence, and a through hole, specifically a threaded hole, is arranged in each of the ceramic boss 600, the ceramic gasket 700 and the threaded sheet 800, and the ceramic boss 600, the ceramic gasket 700 and the threaded sheet 800 are connected by a screw. The material of the threaded sheet 800 can be pure titanium.

[0080] The first sapphire sheet 441 in the vibration excitation device 100 is adhered to the threaded sheet 800 by insulating glue. The third sapphire sheet 443 in the vibration excitation device 100 is adhered to the base 600 by insulating glue. The shape and material of the base 600 can be set as needed, for example, the base 600 can be circular, but it should be noted that the mass of the base 600 is much greater than the sum of the masses of the vibration excitation device 100, the ceramic boss 600, the ceramic gasket 700, the threaded sheet 800 and the quartz crystal oscillator device 200, so as to ensure the stability of the quartz crystal oscillator sensor.

[0081] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0082] In the present application, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "multiple" is at least two, for example, two, three, etc., unless otherwise explicitly specified and limited.

[0083] It should be noted that when an element is referred to as "fixed to" or "arranged on" another element, it can be directly on the other element or there can be a middle element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there can be a middle element. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only implementation.

[0084] Any combination of the technical features in the above embodiments can be made. For the sake of brevity, the foregoing description has not described all possible combinations of the technical features in the above embodiments. However, as long as the combination of the technical features does not contradict, it should be considered within the scope of the present disclosure.

[0085] The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be pointed out that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A quartz crystal microbalance sensor, characterized by, The quartz crystal sensor comprises a vibration excitation device, a quartz crystal device and a detection circuit, the quartz crystal device is connected with the vibration excitation device and the detection circuit respectively; The vibration excitation device is used for generating lateral vibration and normal vibration under the excitation of an excitation signal; The quartz crystal device comprises a first electrode, a second electrode, a wafer and a probe, the first electrode, the second electrode and the probe are connected with the wafer, the probe is used for generating lateral vibration and normal vibration under the driving of the vibration excitation device, and contacting an object to be measured to generate lateral force and normal force in the process of lateral vibration and normal vibration, the first electrode is used for outputting a first electric signal when the wafer is deformed under the action of the lateral force, and the second electrode is used for outputting a second electric signal when the wafer is deformed under the action of the normal force; The detection circuit is used for outputting a detection signal of the lateral force and the normal force according to the first electric signal and the second electric signal; The vibration excitation device comprises an excitation electrode, and the excitation electrode comprises a first excitation electrode; The quartz crystal sensor further comprises an amplification circuit, an input end of the amplification circuit is connected with the first electrode and the second electrode respectively, and an output end of the amplification circuit is connected with the first excitation electrode; The amplification circuit comprises a cross-group amplification circuit, a gain circuit and a phase shift circuit, an input end of the cross-group amplification circuit is connected with the first electrode and the second electrode respectively, an output end of the cross-group amplification circuit is connected with an input end of the gain circuit, an output end of the gain circuit is connected with an input end of the phase shift circuit, and an output end of the phase shift circuit is connected with the first excitation electrode; The cross-group amplification circuit is used for amplifying the first electric signal and the second electric signal, and the gain circuit and the phase shift circuit are respectively used for adjusting the amplitude and the phase of the first electric signal and the second electric signal.

2. The quartz crystal microbalance sensor of claim 1, wherein The wafer is in the shape of a cuboid or a cube; The quartz crystal device comprises four second electrodes corresponding to four side surfaces of the wafer respectively, and each second electrode is connected with a corresponding side surface of the wafer; The quartz crystal device comprises four first electrodes corresponding to four edges of the wafer respectively, and each first electrode is connected with two side surfaces of the wafer on both sides of a corresponding edge.

3. The quartz crystal microbalance sensor of claim 1, wherein The vibration excitation device further comprises a shear ceramic sheet and a normal ceramic sheet, and the excitation electrode, the shear ceramic sheet and the normal ceramic sheet are arranged in a stack; The excitation electrode is used for receiving the excitation signal; The shear ceramic sheet is used for generating lateral vibration under the excitation of the excitation signal; The normal ceramic sheet is used for generating normal vibration under the excitation of the excitation signal.

4. The quartz crystal microbalance sensor of claim 3, wherein The excitation electrode further comprises a second excitation electrode and a grounding electrode; The first excitation electrode is used for receiving the electric signal output by the first electrode and the second electrode as a first excitation signal; The second excitation electrode is used for receiving a second excitation signal output by a phase-locked amplifier of an external device; The grounding electrode is used for grounding.

5. The quartz crystal microbalance sensor of claim 4, wherein The vibration excitation device further comprises a first sapphire sheet, a second sapphire sheet and a third sapphire sheet, the shear ceramic sheet comprises a first shear ceramic sheet and a second shear ceramic sheet, the normal ceramic sheet comprises a first normal ceramic sheet and a second normal ceramic sheet, the first excitation electrode comprises a first sub excitation electrode and a second sub excitation electrode, the second excitation electrode comprises a third sub excitation electrode and a fourth sub excitation electrode, and the ground electrode comprises a first ground electrode and a second ground electrode; The first sapphire sheet, the first sub excitation electrode, the first shear ceramic sheet, the first ground electrode, the second shear ceramic sheet, the third sub excitation electrode, the second sapphire sheet, the second sub excitation electrode, the first normal ceramic sheet, the second ground electrode, the second normal ceramic sheet, the fourth sub excitation electrode and the third sapphire sheet are stacked.

6. The quartz crystal microbalance sensor of claim 1, wherein The cross-group amplification circuit comprises a first amplifier, a first resistor and a second resistor; The first input end of the first amplifier is connected with the first resistor and grounded; The second input end of the first amplifier is connected with the first electrode and the second electrode respectively; The output end of the first amplifier is connected with the input end of the gain circuit; The second resistor is connected between the second input end of the first amplifier and the output end of the first amplifier.

7. The quartz crystal microbalance sensor of claim 1, wherein The gain circuit comprises a second amplifier, a third resistor and a first slide rheostat; The first input end of the second amplifier is grounded; The second input end of the second amplifier is connected with the output end of the cross-group amplification circuit through the third resistor; The output end of the second amplifier is connected with the input end of the phase shift circuit; The first slide rheostat is connected between the second input end of the second amplifier and the output end of the second amplifier.

8. The quartz crystal microbalance sensor of claim 1, wherein, The phase shift circuit comprises a third amplifier, a capacitor, a fourth resistor, a fifth resistor and a second slide rheostat; The first input end of the third amplifier is connected with the output end of the gain circuit through the second slide rheostat, and the first input end of the third amplifier is connected with the capacitor and grounded; The second input end of the third amplifier is connected with the output end of the gain circuit through the fourth resistor, and the second input end of the third amplifier is connected with the output end of the third amplifier through the fifth resistor; The output end of the third amplifier is connected with the first excitation electrode.

9. The quartz crystal microbalance sensor of claim 1, wherein, The quartz crystal sensor further comprises a ceramic boss, a ceramic gasket, a threaded sheet and a base; The quartz crystal device is connected with the vibration excitation device through the ceramic boss, the ceramic gasket and the threaded sheet; The base is connected with the vibration excitation device.

10. The quartz crystal microbalance sensor of claim 1, wherein, The quartz crystal sensor further comprises a sample table for placing the object to be measured; The sample table is arranged at a position with a threshold distance from the probe.

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