A dual-vibrating-beam differential metal-based two-stage amplification quartz resonant pressure sensor and an assembling method thereof

Abstract

A double-vibration-beam differential metal-based two-stage amplification quartz resonant pressure sensor and an assembling method thereof relate to the technical field of micro-mechanical electronic (MEMS) pressure measurement, and comprise a pressure sensor shell, a top cover plate of the pressure sensor shell forms a sensitive chamber, a bottom cover plate and the pressure sensor shell form a PCB mounting chamber, a PCB board is fixed in the PCB mounting chamber, a metal-based two-stage amplification pressure sensitive structure element is connected to a side surface of the pressure sensor shell, the metal-based two-stage amplification pressure sensitive structure element is connected to two quartz double-end fixed support tuning forks, and a temperature sensor is connected to a surface of the metal-based two-stage amplification pressure sensitive structure element; the metal-based two-stage amplification pressure sensitive structure element senses and amplifies a pressure signal change and transmits the pressure signal change to the two quartz double-end fixed support tuning forks to obtain a differential frequency output; and the application improves measurement precision and long-term stability.

Description

Technical Field

[0001] This invention belongs to the technical field of MEMS resonant pressure measurement devices, specifically relating to a dual-beam differential metal-based two-stage amplified quartz resonant pressure sensor and its assembly method. Background Technology

[0002] Resonant pressure sensors, due to their frequency signal output, possess advantages such as strong resistance to electromagnetic interference, good long-term stability, and ease of digital processing, making them widely used in aerospace, precision measurement, and industrial automation. Quartz resonant pressure sensors utilize the piezoelectric and inverse piezoelectric effects, measuring pressure by detecting changes in the natural frequency of a quartz resonant element. Their high frequency output stability makes them particularly suitable for high-precision pressure measurement applications.

[0003] Various quartz resonant pressure sensor structures have been proposed in the prior art. For example, the patent application entitled "Quartz pressure and temperature transducer assembly with dynamic correction" (publication number US8912852B2) adopts the quartz resonance principle, utilizing a quartz resonant element to measure pressure changes and perform accuracy calibration. The patent application entitled "An integrated push-pull structure quartz resonant pressure sensor" (publication number CN112484900B) proposes a pressure transmission structure that transmits pressure to a quartz tuning fork resonant element to achieve pressure measurement. Furthermore, related research shows that mechanical amplification structures can effectively improve the sensitivity of resonant pressure sensors (Kovacs G., Micromachined Transducers Sourcebook, McGraw-Hill, 1998). Based on the above technology, the existing technology proposes a metal-based two-stage amplified quartz resonant pressure sensor structure, which typically includes a metal pressure-sensitive diaphragm, a pressure probe, and a metal flexible lever mechanism. The small displacement generated by the deformation of the diaphragm is transmitted to the input end of the flexible lever through the pressure probe, and the displacement is amplified by the flexible hinge, causing axial displacement at the output end of the lever. This results in axial stress change on the quartz double-ended tuning fork, which changes the resonant frequency and realizes pressure signal detection.

[0004] However, the aforementioned metal-based two-stage amplified quartz resonant pressure sensors typically employ a single-beam structure, meaning that only a single quartz double-ended fixed tuning fork is placed between the output end and the fixed end of the flexible metal lever, as exemplified by the patent application titled "Quartz Resonant Pressure Sensor Based on a Single Pressure Conversion Element" (Publication No. CN116046220A). When temperature changes or residual stress is generated during packaging, the single-beam structure is susceptible to common-mode stress, leading to resonant frequency drift and thus reducing pressure measurement accuracy and long-term stability. Furthermore, the single-beam structure is highly sensitive to environmental stress disturbances and has limited anti-interference capabilities under complex operating conditions.

[0005] Therefore, it is necessary to propose a new quartz resonant pressure sensor structure that, while maintaining the high sensitivity of the metal-based two-stage amplification structure, improves the sensor's ability to suppress temperature changes and residual stress in the packaging, thereby enhancing the pressure measurement accuracy and long-term stability. Summary of the Invention

[0006] To overcome the above-mentioned technical shortcomings, the present invention aims to provide a dual-beam differential metal-based two-stage amplified quartz resonant pressure sensor and its assembly method. By setting two fixed reference ends on a flexible metal lever structure, the two vibrating beams share the same output end displacement and generate reverse stress, thereby realizing differential frequency output. The housing is equipped with four lead posts to realize independent driving and detection of the dual vibrating beams, and the stability is improved by vacuum encapsulation.

[0007] To achieve the above objectives, the technical solution adopted by this invention is as follows: A dual-beam differential metal-based two-stage amplified quartz resonant pressure sensor includes a pressure sensor housing 4, a sensitive chamber formed by the pressure sensor housing 4 and an upper cover plate 5; a PCB mounting chamber formed by the lower cover plate 6 and the pressure sensor housing 4; and a PCB board 7 fixed in the PCB mounting chamber. The pressure sensor housing 4 is connected to a metal-based two-stage amplified pressure-sensitive structural element 1 on its side. The metal-based two-stage amplified pressure-sensitive structural element 1 includes a metal pressure probe structure and a metal flexible lever structure. The metal flexible lever structure includes: a pressure input end 1a, a flexible hinge 1b located in the middle of the lever, a pressure output end 1c located on one side of the flexible hinge 1b, a first fixed reference end 1d rigidly connected to the lever body, a second fixed reference end 1e rigidly connected to the lever body, a positioning groove 1f, and a positioning hole 1j provided at the pressure input end. The metal pressure probe structure includes: a probe housing 1g, a probe sensitive membrane 1h, and a pressure probe tip 1i disposed on the probe sensitive membrane. A first quartz double-ended fixed tuning fork 2 and a second quartz double-ended fixed tuning fork 3 are connected to the metal-based two-stage amplification pressure-sensitive structural element 1 via positioning marks. The first quartz double-ended fixed tuning fork 2 is connected between the pressure output end 1c and the first fixed reference end 1d, and the second quartz double-ended fixed tuning fork 3 is connected between the pressure output end 1c and the second fixed reference end 1e. A temperature sensor 8 is connected to the surface of the metal-based two-stage amplification pressure-sensitive structural element 1. The metal-based two-stage amplification pressure-sensitive structural element 1 senses and amplifies the pressure signal change and transmits it to the first quartz double-ended fixed tuning fork 2 and the second quartz double-ended fixed tuning fork 3 to obtain differential frequency output.

[0008] The pressure sensor housing 4 includes a pressure probe mounting hole 4a located on the side of the pressure sensor housing 4, a glass sintering hole 4b disposed between the sensitive chamber and the PCB mounting chamber, a sintered gold pillar 4c disposed in the glass sintering hole 4b, and a vacuum process hole 4e disposed between the sensitive chamber and the PCB mounting chamber; a positioning boss is provided outside the pressure probe mounting hole 4a; a flexible lever mounting support 4f is provided under the sensitive chamber; the sensitive chamber is connected to the PCB mounting chamber through the glass sintering hole 4b, and the PCB board 7 in the PCB mounting chamber is electrically connected to the first quartz double-ended fixed tuning fork 2 and the second quartz double-ended fixed tuning fork 3 through the sintered gold pillar 4c; The metal pressure probe structure is concentric with the pressure probe mounting hole 4a on the pressure sensor housing 4, and the metal pressure probe structure is connected to the positioning boss on the pressure sensor housing 4; the metal flexible lever structure is connected to the flexible lever mounting support 4f on the pressure sensor housing 4.

[0009] The temperature sensor 8 is located in the sensitive chamber. The temperature sensor 8 is mounted close to the quartz double-ended tuning fork. The pins of the temperature sensor 8 are connected to the PCB board 7 through the sintered gold pillar 4c.

[0010] The lower cover plate 6 has a lead wire hole 6a.

[0011] The PCB board 7 is sealed with epoxy resin.

[0012] The first quartz double-ended fixed tuning fork 2 includes connecting parts 2a and 2b at both ends. The lower surfaces of the connecting parts 2a and 2b are connected to the side of the pressure output end 1c of the metal flexible lever and the first fixed reference end 1d of the flexible lever, and are aligned with the positioning grooves 1f provided on the side of the pressure output end 1c and the first fixed reference end 1d of the flexible lever. The connecting parts 2a and 2b are connected by two symmetrical tuning fork arms 2d. A slit 2c is left between the two tuning fork arms. Electrodes are provided around the surface of the two tuning fork arms 2d, and the electrodes are electrically connected to each other for the tuning fork arms 2d to start oscillating. Under the action of the inverse piezoelectric effect, when an alternating voltage is applied, the tuning fork arms 2d are in a preset vibration mode. A detection electrode is provided on the upper surface of the connecting part 2a at one end, and a solder pad connected to an external circuit is provided on the upper surface of the connecting part 2b at the other end. The solder pad is connected to the PCB board 7 through gold wire.

[0013] The first quartz double-ended fixed tuning fork 2 and the second quartz double-ended fixed tuning fork 3 have completely identical structures; the connection method between the second quartz double-ended fixed tuning fork 3, the pressure output end 1c of the metal flexible lever, and the second fixed reference end 1e of the flexible lever is the same as that of the first quartz double-ended fixed tuning fork 2.

[0014] An assembly method for a dual-beam differential metal-based two-stage amplified quartz resonant pressure sensor includes the following steps: 1) The two ends of the quartz double-ended fixed tuning fork are fixedly connected to the metal flexible lever structure with process adhesive; 2) The flexible metal lever structure and the flexible lever mounting support are connected using laser welding technology; 3) The metal pressure probe structure is sealed and connected to the pressure sensor housing through a welding process; 4) Secure the probe tip to the flexible metal lever structure by applying adhesive. 5) Connect the temperature sensor terminal to the sintered gold pillar via gold wire leads; connect the first quartz double-ended fixed tuning fork and the second quartz double-ended fixed tuning fork to the sintered gold pillar. 6) Weld the top cover plate to the pressure sensor housing; 7) Vacuum the sensitive chamber through the sealing process hole 4e; seal the process hole 4e by welding. 8) Install the PCB board, complete the lead soldering, and seal the PCB mounting cavity with epoxy resin; 9) The lead wires are led out through the lead wire holes on the lower cover plate and the pressure sensor housing is connected to the lower cover plate by welding.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention sets a first fixed reference end and a second fixed reference end on a flexible metal lever structure, and installs a first quartz double-ended fixed tuning fork and a second quartz double-ended fixed tuning fork between the same pressure output end and the two fixed reference ends, respectively. This causes the two resonant tuning forks to generate axial stress changes in opposite directions under pressure, thereby realizing differential frequency output. This can effectively suppress common-mode frequency drift caused by temperature changes and residual stress in the packaging, and improve the accuracy of pressure measurement.

[0016] This invention employs a dual-beam differential structure. By differentially processing the frequency signals of the two resonant tuning forks, the sensor's ability to distinguish minute pressure changes can be significantly improved, while also enhancing the system's anti-interference capability.

[0017] This invention incorporates four electrical connection leads within the pressure sensor housing, enabling the two resonant tuning forks to be driven and detected independently. This improves signal reading stability and facilitates the design of high-precision frequency measurement circuits.

[0018] This invention reduces the impact of air damping on the vibration characteristics of the resonant tuning fork by vacuum sealing within the sensitive chamber, thereby improving the resonance quality factor (Q value) and further enhancing the sensor resolution and long-term stability.

[0019] This invention has a simple structure and high reliability, and is suitable for high-precision pressure measurement applications, such as aerospace, precision instruments and industrial measurement and control. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention.

[0021] Figure 2 This is an exploded view of the overall structure of an embodiment of the present invention.

[0022] Figure 3 This is a cross-sectional view of the shell structure according to an embodiment of the present invention.

[0023] Figure 4 This is a three-dimensional schematic diagram of a metal-based two-stage amplified pressure-sensitive structural element according to an embodiment of the present invention.

[0024] Figure 5 This is a cross-sectional view of the pressure probe structure according to an embodiment of the present invention.

[0025] Figure 6 This is a three-dimensional structural diagram of the metal flexible lever structure according to an embodiment of the present invention.

[0026] Figure 7 This is a schematic diagram of the metal flexible lever structure and the positioning surface of the flexible lever mounting support in an embodiment of the present invention.

[0027] Figure 8This is a schematic diagram of the cover plate structure in an embodiment of the present invention.

[0028] Figure 9 This is a three-dimensional structural diagram of a quartz double-ended fixed tuning fork according to an embodiment of the present invention. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the embodiments and accompanying drawings.

[0030] Reference Figure 1-6 A dual-beam differential metal-based two-stage amplified quartz resonant pressure sensor includes a metal-based two-stage amplified pressure-sensitive structural element 1, a first quartz double-ended fixed tuning fork 2, a second quartz double-ended fixed tuning fork 3, a pressure sensor housing 4, an upper cover plate 5, a lower cover plate 6, a PCB board 7, and a temperature sensor 8. The pressure sensor housing 4 is sequentially connected to the upper cover plate 5, the PCB board 7, and the lower cover plate 6, forming a sensitive chamber with the pressure sensor housing 4 and the upper cover plate 5. The lower cover plate 6 and the pressure sensor housing 4 form a PCB mounting chamber. The PCB board 7 is fixed in the PCB mounting chamber. The upper side of the pressure sensor housing 4 is vacuum-sealed with the upper cover plate 5, and the lower side of the pressure sensor housing 4 is normally sealed with the lower cover plate 6. The pressure sensor housing 4 is connected to a metal-based two-stage amplified pressure-sensitive structural element 1 on its side. The metal-based two-stage amplified pressure-sensitive structural element 1 includes a metal pressure probe structure and a metal flexible lever structure. The metal flexible lever structure includes: a pressure input end 1a, a flexible hinge 1b located in the middle of the lever, a pressure output end 1c located on one side of the flexible hinge 1b, a first fixed reference end 1d rigidly connected to the lever body, a second fixed reference end 1e rigidly connected to the lever body, a positioning groove 1f, and a positioning hole 1j provided at the pressure input end. The metal pressure probe structure includes: a probe housing 1g, a probe sensitive membrane 1h, and a pressure probe tip 1i disposed on the probe sensitive membrane. A first quartz double-ended fixed tuning fork 2 and a second quartz double-ended fixed tuning fork 3 are connected to the metal-based two-stage amplification pressure-sensitive structural element 1 via positioning marks. The first quartz double-ended fixed tuning fork 2 is connected between the pressure output end 1c and the first fixed reference end 1d, and the second quartz double-ended fixed tuning fork 3 is connected between the pressure output end 1c and the second fixed reference end 1e. A temperature sensor 8 is connected to the surface of the metal-based two-stage amplification pressure-sensitive structural element 1. The metal-based two-stage amplification pressure-sensitive structural element 1 senses and amplifies the pressure signal change and transmits it to the first quartz double-ended fixed tuning fork 2 and the second quartz double-ended fixed tuning fork 3 to obtain differential frequency output.

[0031] Reference Figure 3The pressure sensor housing 4 includes a pressure probe mounting hole 4a located on the side of the pressure sensor housing 4, a glass sintering hole 4b disposed between the sensitive chamber and the PCB mounting chamber, a sintered gold pillar 4c disposed in the glass sintering hole 4b, and a vacuum process hole 4e disposed between the sensitive chamber and the PCB mounting chamber; a positioning boss is provided outside the pressure probe mounting hole 4a; and a flexible lever mounting support 4f is provided under the sensitive chamber.

[0032] The sensitive chamber is connected to the PCB mounting chamber through the glass sintering hole 4b on the pressure sensor housing 4. The PCB board 7 in the PCB mounting chamber is electrically connected to the first quartz double-ended fixed tuning fork 2 and the second quartz double-ended fixed tuning fork 3 through the sintered gold pillar 4c. Reference Figure 3 , Figure 7 The metal pressure probe structure is concentric with the pressure probe mounting hole 4a on the pressure sensor housing 4, and the metal pressure probe structure is connected to the positioning boss on the pressure sensor housing 4; the metal flexible lever structure is connected to the flexible lever mounting support 4f on the pressure sensor housing 4, the a surface of the metal flexible lever structure is tightly connected to the d surface of the flexible lever mounting support 4f, the b surface of the metal flexible lever structure is tightly connected to the e surface of the flexible lever mounting support 4f, and the c surface of the metal flexible lever structure is tightly connected to the f surface of the flexible lever mounting support 4f.

[0033] The temperature sensor 8 is located in the sensitive chamber. The temperature sensor 8 is mounted close to the quartz double-ended tuning fork. The pins of the temperature sensor 8 are connected to the PCB board 7 through the sintered gold pillar 4c.

[0034] Reference Figure 8 The lower cover plate 6 has lead wire holes 6a for lead wires to be led out of the PCB mounting cavity and for sealing the cavity.

[0035] The PCB board 7 is sealed with epoxy resin.

[0036] Reference Figure 9The first quartz double-ended fixed tuning fork 2 includes connecting parts 2a and 2b at both ends. The lower surfaces of the connecting parts 2a and 2b are connected to the side of the pressure output end 1c of the metal flexible lever and the first fixed reference end 1d of the flexible lever, and are aligned with the positioning grooves 1f provided on the side of the pressure output end 1c and the first fixed reference end 1d of the flexible lever. The connecting parts 2a and 2b are connected by two symmetrical tuning fork arms 2d. A slit 2c is left between the two tuning fork arms. Electrodes are provided around the surface of the two tuning fork arms 2d, and the electrodes are electrically connected to each other for the tuning fork arms 2d to start oscillating. Under the action of the inverse piezoelectric effect, when an alternating voltage is applied, the tuning fork arms 2d are in a preset vibration mode. A detection electrode is provided on the upper surface of the connecting part 2a at one end, and a solder pad connected to an external circuit is provided on the upper surface of the connecting part 2b at the other end. The solder pad is connected to the PCB board 7 through gold wire.

[0037] The first quartz double-ended fixed tuning fork 2 and the second quartz double-ended fixed tuning fork 3 have completely identical structures; the connection method between the second quartz double-ended fixed tuning fork 3 and the pressure output end 1c of the metal flexible lever and the second fixed reference end 1e of the flexible lever is the same as that of the first quartz double-ended fixed tuning fork 2.

[0038] An assembly method for a dual-beam differential metal-based two-stage amplified quartz resonant pressure sensor includes the following steps: 1) Align the two ends of the quartz double-ended fixed tuning fork with the positioning groove marks on the side of the metal flexible lever, and then fix them to the metal flexible lever with process adhesive. 2) Align the metal flexible lever with the flexible lever mounting support seat by means of the positioning relationship between the positioning surfaces a, b, and c of the metal flexible lever and the positioning surfaces d, e, and f of the flexible lever mounting support seat on the pressure sensor housing 4, and connect the metal flexible lever with the flexible lever mounting support seat by means of laser welding. 3) The metal pressure probe structure is concentric with the pressure probe mounting hole 4a and fits against the positioning boss on the pressure sensor housing 4. It is sealed and connected to the pressure sensor housing 4 by welding process; the probe tip is concentric with the positioning hole of the metal flexible lever and is inserted into the positioning hole. 4) Secure the probe tip to the flexible metal lever by applying adhesive. 5) Connect the temperature sensor 8 terminals to the sintered gold pillar 4c via gold wire leads; connect the first quartz double-ended fixed tuning fork 2 and the second quartz double-ended fixed tuning fork 3 to the sintered gold pillar 4c. 6) Weld the top cover plate 1 to the pressure sensor housing 4; 7) Vacuum the sensitive chamber through the sealing process hole 4e; seal the process hole 4e by welding. 8) Install PCB board 7, complete electrical connection, and seal the PCB mounting cavity with epoxy resin; 9) The lead wire is led out through the lead wire hole 6a on the lower cover plate 6 and connected to the pressure sensor housing 4 and the lower cover plate 6 by welding.

[0039] The beneficial effects of this embodiment are as follows: By symmetrically arranging two quartz double-ended fixed tuning forks on a flexible metal lever structure, the two resonant tuning forks generate axial stress changes in opposite directions under pressure, thereby forming a differential frequency output signal. Compared with traditional single-beam quartz resonant pressure sensors, this embodiment can effectively suppress common-mode frequency drift caused by temperature changes and residual stress in the packaging, improving pressure measurement accuracy and long-term stability. Simultaneously, the vacuum packaging structure improves the quality factor of the resonant tuning forks, giving the sensor higher frequency resolution and better measurement stability.

[0040] This invention is not limited to the above embodiments. Based on the technical solutions disclosed in this invention, those skilled in the art can make some substitutions and modifications to some of the technical features without creative effort, and all such substitutions and modifications are within the protection scope of this invention.

Claims

1. A dual-beam differential metal-based two-stage amplified quartz resonant pressure sensor, comprising a pressure sensor housing (4), characterized in that: The pressure sensor housing (4) and the upper cover plate (5) form a sensitive chamber; the lower cover plate (6) and the pressure sensor housing (4) form a PCB mounting chamber; the PCB board is fixed in the PCB mounting chamber; The pressure sensor housing (4) is connected to a metal-based two-stage amplified pressure-sensitive structural element (1) on the side. The metal-based two-stage amplified pressure-sensitive structural element (1) includes a metal pressure probe structure and a metal flexible lever structure. The metal flexible lever structure includes: a pressure input end (1a), a flexible hinge (1b) disposed in the middle of the lever, a pressure output end (1c) located on one side of the flexible hinge (1b), a first fixed reference end (1d) rigidly connected to the lever body, a second fixed reference end (1e) rigidly connected to the lever body, a positioning groove (1f), and a positioning hole (1j) disposed at the pressure input end; the metal pressure probe structure includes: a probe housing (1g), a probe sensitive membrane (1h), and a pressure probe tip (1i) disposed on the probe sensitive membrane. A first quartz double-ended fixed tuning fork (2) and a second quartz double-ended fixed tuning fork (3) are connected to the metal-based two-stage amplified pressure-sensitive structural element (1) by positioning marks. The first quartz double-ended fixed tuning fork (2) is connected between the pressure output end (1c) and the first fixed reference end (1d), and the second quartz double-ended fixed tuning fork (3) is connected between the pressure output end (1c) and the second fixed reference end (1e). A temperature sensor (8) is connected to the surface of the metal-based two-stage amplified pressure-sensitive structural element (1). The metal-based two-stage amplified pressure-sensitive structural element (1) senses and amplifies the pressure signal change and transmits it to the first quartz double-ended fixed tuning fork (2) and the second quartz double-ended fixed tuning fork (3) to obtain differential frequency output.

2. The pressure sensor according to claim 1, characterized in that: The pressure sensor housing (4) includes a pressure probe mounting hole (4a) on the side of the pressure sensor housing (4), a glass sintering hole (4b) between the sensitive chamber and the PCB mounting chamber, a sintered gold pillar (4c) in the glass sintering hole (4b), and a vacuum process hole (4e) between the sensitive chamber and the PCB mounting chamber; a positioning boss is provided outside the pressure probe mounting hole (4a); a flexible lever mounting support (4f) is provided under the sensitive chamber; the sensitive chamber is connected to the PCB mounting chamber through the glass sintering hole (4b), and the PCB board (7) in the PCB mounting chamber is electrically connected to the first quartz double-ended fixed tuning fork (2) and the second quartz double-ended fixed tuning fork (3) through the sintered gold pillar (4c); the metal pressure probe structure is concentric with the pressure probe mounting hole (4a) on the pressure sensor housing (4), and the metal pressure probe structure is connected to the positioning boss on the pressure sensor housing (4); the metal flexible lever structure is connected to the flexible lever mounting support (4f) on the pressure sensor housing (4).

3. The pressure sensor according to claim 2, characterized in that: The temperature sensor (8) is located in the sensitive chamber. The temperature sensor (8) is mounted close to the quartz double-ended fixed tuning fork. The pins of the temperature sensor (8) are connected to the PCB board (7) through sintered gold pillars (4c).

4. The pressure sensor according to claim 1, characterized in that: The lower cover plate (6) has a lead wire hole (6a).

5. The pressure sensor according to claim 1, characterized in that: The PCB board (7) is sealed with epoxy resin.

6. The pressure sensor according to claim 1, characterized in that: The first quartz double-ended fixed tuning fork (2) includes connecting parts (2a, 2b) at both ends. The lower surface of the connecting parts (2a, 2b) is connected to the side of the pressure output end (1c) of the metal flexible lever and the first fixed reference end (1d) of the flexible lever. It is aligned with the positioning groove (1f) provided on the side of the pressure output end (1c) of the metal flexible lever and the first fixed reference end (1d) of the flexible lever. The connecting parts (2a, 2b) are connected by two symmetrical tuning fork arms (2d). A slit (2c) is left between the two tuning fork arms. Electrodes are provided around the surface of the two tuning fork arms (2d). The electrodes are electrically connected to each other and used to start the tuning fork arms (2d) to vibrate. Under the action of the inverse piezoelectric effect, when the alternating voltage is applied, the tuning fork arms (2d) are in a preset vibration mode. A detection electrode is provided on the upper surface of the connecting part (2a) at one end, and a solder pad connected to the external circuit is provided on the upper surface of the connecting part (2b) at the other end. The solder pad is connected to the PCB board (7) through gold wire.

7. The pressure sensor according to claim 6, characterized in that: The first quartz double-ended fixed tuning fork (2) and the second quartz double-ended fixed tuning fork (3) have the same structure; the connection method between the second quartz double-ended fixed tuning fork (3), the pressure output end (1c) of the metal flexible lever, and the second fixed reference end (1e) of the flexible lever is the same as that of the first quartz double-ended fixed tuning fork (2).

8. The assembly method of a dual-beam differential metal-based two-stage amplified quartz resonant pressure sensor according to any one of claims 1-7, characterized in that, Includes the following steps: 1) The two ends of the quartz double-ended fixed tuning fork are fixedly connected to the metal flexible lever structure with process adhesive; 2) The flexible metal lever structure and the flexible lever mounting support are connected using laser welding technology; 3) The metal pressure probe structure is sealed and connected to the pressure sensor housing through a welding process; 4) Secure the probe tip to the flexible metal lever structure by applying adhesive. 5) Connect the temperature sensor terminal to the sintered gold pillar via gold wire leads; connect the first quartz double-ended fixed tuning fork and the second quartz double-ended fixed tuning fork to the sintered gold pillar. 6) Weld the top cover plate to the pressure sensor housing; 7) Vacuum the sensitive chamber by sealing the process orifice; seal the process orifice by welding. 8) Install the PCB board, complete the lead soldering, and seal the PCB mounting cavity with epoxy resin; 9) The lead wires are led out through the lead wire holes on the lower cover plate and the pressure sensor housing is connected to the lower cover plate by welding.

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