High-sensitivity wide-range piezoelectric pressure sensor

Abstract

The invention relates to the technical field of semiconductor piezoelectric measurement, in particular to a high-sensitivity wide-range piezoelectric pressure sensor, and mainly solves the technical problem that the sensitivity and the insulativity of an existing piezoelectric pressure sensor cannot be achieved at the same time. The piezoelectric pressure sensor comprises a metal housing, which is provided with an annular installation cavity; the pressure-sensitive unit is pressed in the mounting cavity and comprises two wafers and an electrode plate, the electrode plate is clamped between the two wafers, and the wafers are of a sandwich structure formed by growing insulating layers on the two end faces of a polarized ferroelectric crystal; and the connector comprises a tubular joint and a middle shaft coaxially fixed in the tubular joint, the tubular joint is electrically connected with the metal shell, and the middle shaft is electrically connected with the electrode plates. The piezoelectric pressure sensor not only has the characteristic of high sensitivity, but also enables the insulation resistance output by the sensor to be effectively improved due to the arrangement of the insulating layer, so that stable output under a quasi-static condition can be realized.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor piezoelectric measurement technology, in particular to a piezoelectric pressure sensor with high sensitivity and wide range. Background Art

[0002] A piezoelectric pressure sensor converts pressure signals into electrical signals using the piezoelectric effect. Among various pressure sensor types, piezoelectric pressure sensors are highly favored in industrial pressure testing due to their self-powered design, simple structure, wide bandwidth, and high sensitivity. They are widely used in dynamic pressure testing.

[0003] The main piezoelectric single crystal materials for piezoelectric pressure sensors are quartz and ferroelectric crystals. Quartz crystals offer excellent mechanical properties, exceptional temperature stability, and good insulation properties, effectively limiting leakage current and endowing the sensor with excellent charge retention. However, the piezoelectric sensitivity of quartz crystals is relatively low, making them difficult to meet high-sensitivity measurement requirements, limiting their application in some scenarios requiring precise measurements. Ferroelectric crystals contain reversible polarization domains. After polarization, the domain structure changes under external pressure, generating a significant charge output. This piezoelectric effect, manifested by macroscopic mapping of the dynamic behavior of the polarization domains, exhibits a piezoelectric constant in specific directions much higher than that of quartz, resulting in piezoelectric sensors made from ferroelectric crystals having higher sensitivity. However, common ferroelectric crystals, such as lead zirconate titanate (PZT), lithium niobate (LiNbO3), and lithium tantalate (LiTaO3), have low resistivity and inferior insulation properties to quartz. Consequently, piezoelectric pressure sensors made from ferroelectric crystals have low insulation resistance, making it difficult to achieve stable output under quasi-static conditions. These piezoelectric pressure sensors are primarily used for dynamic detection, such as accelerometers.

[0004] Therefore, there is an urgent need for a piezoelectric pressure sensor with high sensitivity and good insulation. Summary of the Invention

[0005] In order to overcome the technical defect of the existing piezoelectric pressure sensor that sensitivity and insulation cannot be achieved at the same time, the present invention provides a piezoelectric pressure sensor with high sensitivity and wide range.

[0006] The present invention provides a high-sensitivity, wide-range piezoelectric pressure sensor comprising: A metal shell is formed with an annular installation cavity, and a side wall of the installation cavity is provided with an installation window; A pressure-sensitive unit is press-placed in the mounting cavity and includes two wafers and an electrode sheet. The wafers and electrode sheet are both annular and coaxially arranged. The electrode sheet is sandwiched between the two wafers. The wafers are a sandwich structure formed by growing insulating layers on both end faces of a polarized ferroelectric crystal. The connector includes a tubular joint and a central shaft coaxially fixed in the tubular joint, wherein the tubular joint is fixed at the installation window and electrically connected to the metal shell, and the central shaft is electrically isolated from the tubular joint and electrically connected to the electrode sheet.

[0007] Optionally, the metal shell includes an annular base, an annular pressure cover and an outer ring. The annular base and the annular pressure cover are coaxially arranged and separated up and down to form the installation cavity. The pressure-sensitive unit is pressed between the annular base and the annular pressure cover. The outer ring is sleeved on the outer circular surface of the annular base and the outer circular surface of the annular pressure cover, and the installation window is opened on the outer ring.

[0008] Optionally, the inner edge of the upper surface of the annular base is protruded upward to form an inner cylinder, the top of the inner cylinder is sleeved on the inner circular surface of the annular pressure cover, and the pressure sensitive unit is electrically isolated from the inner cylinder.

[0009] Optionally, an insulating cylinder is provided between the pressure-sensitive unit and the inner cylinder to achieve electrical isolation.

[0010] Optionally, the outer circular surface of the annular pressure cover is provided with a first convex ring, the top of the outer ring is sleeved on the first convex ring, the inner circular surface of the annular pressure cover is provided with a second convex ring, the top of the inner cylinder is sleeved on the second convex ring, and the radial middle part of the annular pressure cover is convex to form an annular pressing part.

[0011] Optionally, a third convex ring is provided at the bottom of the outer circular surface of the annular base, and the bottom end of the outer ring abuts against the third convex ring.

[0012] Optionally, the ferroelectric crystal is a Z-cut LiTaO3 single crystal, and the insulating layer is a SiO2 thin film.

[0013] Optionally, the SiO2 film is grown on the end face of the Z-cut LiTaO3 single crystal by plasma enhanced chemical vapor deposition.

[0014] Optionally, the axis of the connector is parallel to the wafer, and the tubular joint is provided with an external thread.

[0015] Optionally, the central axis is electrically connected to the electrode sheet via a wire.

[0016] The technical solution provided by the present invention has the following advantages compared with the prior art: 1) The highly sensitive, wide-range piezoelectric pressure sensor provided by the present invention has a wafer with a sandwich structure formed by growing insulating layers on both end faces of a ferroelectric crystal. This structure not only retains the high sensitivity of the ferroelectric crystal, but also effectively improves the insulation resistance of the sensor output due to the insulating layers, thereby effectively alleviating the problem of charge leakage in quasi-static scenarios and achieving stable output under quasi-static conditions. 2) The highly sensitive, wide-range piezoelectric pressure sensor provided by the present invention has a pressure-sensitive unit consisting of two wafers and an electrode sheet sandwiched between the two wafers. The two wafers are arranged in parallel, which can nearly double the charge output at the expense of a smaller volume, thereby further improving the sensitivity of the sensor. 3) The highly sensitive, wide-range piezoelectric pressure sensor provided by the present invention, due to its high sensitivity, can output extremely high charge under high pressure conditions. Combined with the high insulation resistance achieved by the wafer sandwich structure, it can achieve more stable charge retention, making it more suitable for quasi-static measurement scenarios with high precision requirements. 4) The high-sensitivity, wide-range piezoelectric pressure sensor provided by the present invention presses the pressure-sensitive unit into a metal shell. The metal shell provides a pre-tightening force to the pressure-sensitive unit, which can effectively improve the problem of nonlinear output of the pressure-sensitive unit when subjected to smaller pressures. At the same time, the metal shell provides high mechanical strength protection for the pressure-sensitive unit, enabling the sensor to withstand greater pressure and vibration and have a wider range. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0019] Figure 1 A top view of a piezoelectric pressure sensor according to an embodiment of the present invention is shown; Figure 2 express Figure 1 Cross-sectional view at AA in the middle; Figure 3 A schematic diagram showing two wafers arranged in parallel in an embodiment of the present invention; Figure 4 A charge-time relationship curve diagram during a dynamic pressure test according to an embodiment of the present invention is shown; Figure 5 A charge-pressure relationship curve diagram during a dynamic pressure test according to an embodiment of the present invention is shown; Figure 6 A graph showing a response characteristic test curve of a piezoelectric pressure sensor according to an embodiment of the present invention; Figure 7 A graph showing a resolution test curve of a piezoelectric pressure sensor according to an embodiment of the present invention; Figure 8 A charge-time relationship curve diagram during a quasi-static pressure test according to an embodiment of the present invention is shown; Figure 9 A charge-pressure relationship curve diagram during a quasi-static pressure test in an embodiment of the present invention is shown.

[0020] In the picture: 1. Metal shell; 11. Mounting cavity; 12. Mounting window; 13. Annular base; 131. Third convex ring; 14. Annular pressure cover; 141. First convex ring; 142. Second convex ring; 143. Annular pressing part; 15. Outer ring; 16. Inner cylinder; 17. Insulating cylinder; 2. Pressure-sensitive unit; 21. Wafer; 22. Electrode sheet; 3. Connector; 31. Tubular joint; 32. Central axis; 4. Wire. DETAILED DESCRIPTION

[0021] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0022] In the description, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance. It should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood broadly. For example, they can refer to fixed connections, removable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms based on specific circumstances.

[0023] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all the embodiments.

[0024] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0025] Reference Figures 1 to 3 This embodiment provides a piezoelectric pressure sensor with high sensitivity and wide range, including a metal shell 1, a pressure-sensitive unit 2 and a connector 3.

[0026] The metal shell 1 is formed with an annular installation cavity 11 , and a installation window 12 is provided on a side wall of the installation cavity 11 .

[0027] It is easy to understand that the mounting cavity 11 is used to mount the pressure-sensitive unit 2 , and the mounting window 12 is used to mount the connector 3 .

[0028] It should be noted that the metal shell 1 needs to be made of a metal with good conductive properties such as copper to ensure that it has good electrical properties, so that it can form a good electrical connection with the upper and lower surfaces of the pressure-sensitive unit 2 located in the annular cavity, and serve as one pole of the output electrode of the piezoelectric pressure sensor.

[0029] Specifically, the metal shell 1 includes an annular base 13, an annular pressure cover 14, and an outer ring 15. The annular base 13 and the annular pressure cover 14 are coaxially arranged and spaced apart from each other to form a mounting cavity 11. The pressure-sensitive unit 2 is pressed between the annular base 13 and the annular pressure cover 14. The outer ring 15 is sleeved on the outer circumferential surfaces of the annular base 13 and the annular pressure cover 14. The mounting window 12 is opened on the outer ring 15. The outer ring 15 can protect the outside of the pressure-sensitive unit 2, effectively preventing mechanical damage and environmental interference. At the same time, it can also realize the electrical connection between the annular base 13 and the annular pressure cover 14, so that the outer ring 15, the annular base 13, and the annular pressure cover 14 can serve as electrodes.

[0030] More specifically, the inner edge of the upper surface of the annular base 13 is convexly formed to form an inner cylinder 16, the top of which is sleeved onto the inner circumferential surface of the annular gland 14, electrically isolating the pressure-sensitive unit 2 from the inner cylinder 16. The inner cylinder 16 protects the inner side of the pressure-sensitive unit 2 while also achieving electrical connection between the annular base 13 and the annular gland 14, so that the outer ring 15, the annular base 13, the annular gland 14, and the inner cylinder 16 collectively serve as electrodes.

[0031] Specifically, an insulating tube 17 is provided between the pressure-sensitive unit 2 and the inner tube 16 to achieve electrical isolation. This insulating tube 17 has two advantages: first, it provides electrical isolation between the pressure-sensitive unit 2 and the inner tube 16; second, the pressure-sensitive unit 2 is secured to the insulating tube 17, compensating for errors in the dicing and packaging processes of the pressure-sensitive unit 2.

[0032] Specifically, the outer surface of the annular gland 14 is provided with a first bead 141, onto which the top of the outer ring 15 is fitted. A second bead 142 is provided on the inner surface of the annular gland 14, onto which the top of the inner cylinder 16 is fitted. The radially central portion of the annular gland 14 is convex upward to form an annular pressing portion 143. The provision of the first and second bead 141, 142 facilitates assembly of the annular gland 14, while the provision of the annular pressing portion 143 effectively prevents compression of the outer ring 15 and inner cylinder 16 during testing, thereby preventing structural damage caused by such compression.

[0033] In detail, a third convex ring 131 is provided at the bottom of the outer circumference of the annular base 13, and the bottom end of the outer ring 15 abuts against the third convex ring 131. The third convex ring 131 can axially limit the outer ring 15, which is more conducive to improving the stability of the overall structure.

[0034] The metal shell of this embodiment has high mechanical strength and can withstand large pressure and vibration, so that the piezoelectric pressure sensor can withstand a maximum pressure of several thousand Newtons. In addition, the annular hollow structure used in the package has excellent anti-eccentric load capability.

[0035] Among them, the pressure-sensitive unit 2 is pressed into the installation cavity 11 and includes two wafers 21 and an electrode piece 22. The wafer 21 and the electrode piece 22 are both annular and coaxially arranged. The electrode piece 22 is sandwiched between the two wafers 21. The wafer 21 is a sandwich structure formed by growing an insulating layer on both end faces of a polarized ferroelectric crystal.

[0036] It should be noted that ferroelectric crystals have high sensitivity, but their insulation properties are poor. In this embodiment, insulating layers are grown on both end faces of the ferroelectric crystal to form a sandwich structure, which can overcome the disadvantage of poor insulation while maintaining its high sensitivity advantage, thereby obtaining a wafer 21 with high sensitivity and high insulation properties.

[0037] It is easy to understand that when the pressure-sensitive unit 2 is placed in the installation cavity 11, it is necessary to control the two sides of the wafers 21 with the same polarization direction to be connected through electrodes. For example, in this embodiment, the upper surface of the upper wafer 21 is the polarization negative end and the lower surface is the polarization positive end, while the upper surface of the lower wafer 21 is the polarization positive end and the lower surface is the polarization negative end. The electrode sheet 22 serves as a positive electrode to connect the polarization positive ends of the two wafers 21, and the metal shell serves as a negative electrode to connect the polarization negative ends of the two wafers 21, thereby forming a structure in which the two wafers 21 are connected in parallel.

[0038] It should be noted that the insulating layer is sandwiched between the ferroelectric crystal and the electrode as a dielectric. When the polarization end of the ferroelectric crystal generates charge, it can generate induced charge on the surface of the corresponding electrode.

[0039] Specifically, the ferroelectric crystal is a Z-cut LiTaO3 single crystal, and the insulating layer is a SiO2 thin film.

[0040] More specifically, the Z-cut LiTaO 3 single crystal selected in this embodiment has a thickness of 1 mm, an inner diameter of 6 mm, and an outer diameter of 15 mm.

[0041] More specifically, SiO2 thin films were grown on the end faces of Z-cut LiTaO3 single crystals by plasma enhanced chemical vapor deposition.

[0042] It is easy to understand that the annular base 13 , the annular pressure cover 14 and the electrode sheet 22 must all be able to completely cover the wafer 21 , so the areas of the annular base 13 , the annular pressure cover 14 and the electrode sheet 22 can be designed to be larger than the area of the wafer 21 .

[0043] The connector 3 includes a tubular joint 31 and a central axis 32 coaxially fixed in the tubular joint 31 . The tubular joint 31 is fixed at the installation window 12 and electrically connected to the metal shell 1 . The central axis 32 is electrically isolated from the tubular joint 31 and electrically connected to the electrode sheet 22 .

[0044] It should be noted that Figure 2 The figure only illustrates the positional relationship between the central shaft 32 and the tubular joint 31, but does not show the internal structure of the central shaft 32. It will be clear to those skilled in the art that because the central shaft 32 needs to be both electrically isolated from the tubular joint 31 and electrically connected to the electrode sheet 22, the central shaft 32 should include two parts: one for electrically connecting to the electrode sheet 22 and the other for electrically isolating from the tubular joint 31. For example, the central shaft 32 can be designed as a sleeve structure, i.e., the central shaft 32 includes a conductive inner tube and an insulating outer tube. The conductive inner tube is electrically connected to the electrode sheet 22, and the insulating outer tube is located between the conductive inner tube and the tubular joint 31 to electrically isolate the central shaft 32 from the tubular joint 31.

[0045] It is easy to understand that the tubular joint 31 is electrically connected to the metal shell 1 to extend the negative electrode, and the central axis 32 is electrically connected to the electrode sheet 22 to extend the positive electrode. In this way, when testing, it is only necessary to connect the device to the connector 3 to form a test circuit.

[0046] Specifically, the axis of the connector 3 is parallel to the wafer 21 , and the tubular joint 31 is provided with an external thread, which is more conducive to connection with external equipment.

[0047] Specifically, the central axis 32 is electrically connected to the electrode sheet 22 via the wire 4 to ensure stable transmission of the electrical signal.

[0048] Specifically, the connector 3 adopts the standard radio frequency GM5-ZBF specification.

[0049] Specifically, the tubular joint 31 can be fixed to the installation window 12 by welding or screws, etc., to ensure the firmness and reliability of the connection.

[0050] The test process of the high-sensitivity, wide-range piezoelectric pressure sensor of this embodiment is as follows: 1) Fix the piezoelectric pressure sensor on the platform of the universal pressure testing machine to ensure good contact between the piezoelectric pressure sensor and the platform to avoid measurement errors caused by poor contact; 2) Connect the charge amplifier to connector 3 of the piezoelectric pressure sensor via a shielded cable, and connect the oscilloscope to the charge amplifier via a coaxial cable to ensure the stability and accuracy of signal transmission; 3) The servo motor pushes and applies pressure, and the generated charge is collected by the charge amplifier and converted into a voltage signal, which is then input into the oscilloscope for display and analysis; 4) Gradually increase the pressure and record the corresponding charge output and voltage signal.

[0051] Figure 4 The figure shows the charge output results of the piezoelectric pressure sensor of this embodiment under different dynamic pressures. During operation, the piezoelectric pressure sensor is subjected to a dynamic pressure test in the pressure range of 1kN-6kN with a step size of 0.5kN or 1kN. The test is repeated three times at each pressure, and the peak pressure applied by the universal pressure testing machine and the peak value of the charge output by the piezoelectric pressure sensor are recorded. As can be seen from the figure, the output of the piezoelectric pressure sensor has good stability and repeatability. It should be noted that although the universal pressure testing machine can set the expected pressure, due to the limitations of the control program of the equipment itself, there is a certain error between the actual pressure applied to the piezoelectric pressure sensor and the set pressure, so it is necessary to calculate the output linearity of the piezoelectric pressure sensor in combination with the actual pressure peak.

[0052] Figure 5 The linear fitting result of the output charge and applied pressure value of the piezoelectric pressure sensor of this embodiment in the dynamic pressure test is shown in the figure. As can be seen from the figure, the determination coefficient R 2 =0.996, indicating that the output charge and pressure of the piezoelectric pressure sensor have good linearity; the sensitivity is 137.5pC / N, and the wafer 21 with a surface sandwich structure has extremely high output sensitivity while increasing the sensor input resistance.

[0053] Figure 6 Figure 3 shows the response characteristics of the piezoelectric pressure sensor of this embodiment. During operation, a shock wave generated by a shock tube briefly applies rapid pressure to the piezoelectric pressure sensor to test its response time. As shown in the figure, after multiple tests, the piezoelectric pressure sensor has an average response time of 3 μs, demonstrating rapid response capability.

[0054] Figure 7 The figure shows the resolution results of the piezoelectric pressure sensor of this embodiment. As can be seen from the figure, the piezoelectric pressure sensor can accurately distinguish tiny pressure differences within the pressure range of at least 10-55N, with a resolution better than 1%.

[0055] Figure 8 shows the charge retention results of the piezoelectric pressure sensor of this embodiment under quasi-static pressure. As can be seen, after 10 minutes of charge retention, the output charge of the piezoelectric pressure sensor only dropped by 577.9 - 568.7 = 9.2 kJ, with a rate of change of less than 1.6%, demonstrating the piezoelectric pressure sensor's excellent charge retention.

[0056] Figure 9 The figure shows the linear fitting results of the output charge and applied pressure of the piezoelectric pressure sensor of this embodiment during the quasi-static stress test. During operation, the quasi-static test was performed within the pressure range of 0-6 kN, with 1 kN increments and a pressure holding time of 10 seconds at each increment. The charge output during the pressure holding phase and the pressure change phase was observed to evaluate the stability and linearity of the piezoelectric pressure sensor. In the quasi-static stress test, the calculated sensitivity of the sensor was 132.2 pC / N, and the determination coefficient R of the fitting result was 132.2 pC / N. 2 =0.995, indicating that the piezoelectric pressure sensor has good linearity. It should be noted that during the test, the test environment temperature must be strictly controlled at 20°C to reduce the impact of the pyroelectric effect.

[0057] The highly sensitive and wide-range piezoelectric pressure sensor of this embodiment can significantly improve the pressure measurement accuracy and optimize product quality and production efficiency in industrial production. For example, it can ensure the precise assembly of parts and reduce the defective rate in automobile manufacturing. In terms of environmental monitoring, it is suitable for scenarios such as water pressure and gas pressure monitoring, helping to promptly detect and deal with environmental problems. What is particularly outstanding is that this piezoelectric pressure sensor exhibits excellent performance in quasi-static scenarios. Through high-precision measurement and stable charge retention capabilities, it effectively solves the charge loss problem of traditional piezoelectric sensors in quasi-static measurements, ensuring the reliability of long-term monitoring. At the same time, its high stability and anti-interference ability enable it to operate stably for a long time in harsh environments, reduce the frequency of equipment maintenance and replacement, reduce the total cost of ownership, and have significant social and economic benefits.

[0058] The above description is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions have been made with reference to the aforementioned embodiments, those skilled in the art should understand that they may still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents; and such modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments, and they should all be included in the scope of protection of the claims.

Claims

1. A high-sensitivity, wide-range piezoelectric pressure sensor, characterized in that: include: A metal shell (1) is formed with an annular installation cavity (11), and a side wall of the installation cavity (11) is provided with an installation window (12); A pressure-sensitive unit (2) is pressed into the mounting cavity (11) and comprises two wafers (21) and an electrode sheet (22), wherein the wafers (21) and the electrode sheet (22) are both annular and coaxially arranged, and the electrode sheet (22) is sandwiched between the two wafers (21). The wafer (21) is a sandwich structure formed by growing insulating layers on both end faces of a polarized ferroelectric crystal. A connector (3) comprising a tubular joint (31) and a central shaft (32) coaxially fixed in the tubular joint (31), wherein the tubular joint (31) is fixed at the installation window (12) and electrically connected to the metal shell (1), and the central shaft (32) is electrically isolated from the tubular joint (31) and electrically connected to the electrode sheet (22).

2. The high-sensitivity, wide-range piezoelectric pressure sensor according to claim 1, characterized in that: The metal shell (1) includes an annular base (13), an annular pressure cover (14) and an outer ring (15), wherein the annular base (13) and the annular pressure cover (14) are coaxially arranged and spaced apart from each other to form the installation cavity (11), and the pressure-sensitive unit (2) is pressed between the annular base (13) and the annular pressure cover (14), and the outer ring (15) is sleeved on the outer circular surface of the annular base (13) and the outer circular surface of the annular pressure cover (14), and the installation window (12) is opened on the outer ring (15).

3. The high-sensitivity, wide-range piezoelectric pressure sensor according to claim 2, characterized in that: The inner edge of the upper surface of the annular base (13) is convex upward to form an inner cylinder (16), the top of the inner cylinder (16) is sleeved on the inner circular surface of the annular pressure cover (14), and the pressure-sensitive unit (2) is electrically isolated from the inner cylinder (16).

4. The high-sensitivity, wide-range piezoelectric pressure sensor according to claim 3, characterized in that: An insulating cylinder (17) is provided between the pressure-sensitive unit (2) and the inner cylinder (16) to achieve electrical isolation.

5. The high-sensitivity, wide-range piezoelectric pressure sensor according to claim 3 or 4, characterized in that: The outer circumferential surface of the annular pressure cover (14) is provided with a first convex ring (141), the top of the outer ring (15) is sleeved on the first convex ring (141), the inner circumferential surface of the annular pressure cover (14) is provided with a second convex ring (142), the top of the inner cylinder (16) is sleeved on the second convex ring (142), and the radial middle part of the annular pressure cover (14) is convex upward to form an annular pressing portion (143).

6. The high-sensitivity, wide-range piezoelectric pressure sensor according to claim 5, characterized in that: A third convex ring (131) is provided at the bottom of the outer circumferential surface of the annular base (13), and the bottom end of the outer ring (15) abuts against the third convex ring (131).

7. The high-sensitivity, wide-range piezoelectric pressure sensor according to claim 1, characterized in that: The ferroelectric crystal is a Z-cut LiTaO3 single crystal, and the insulating layer is a SiO2 thin film.

8. The high-sensitivity, wide-range piezoelectric pressure sensor according to claim 7, characterized in that: The SiO2 film is grown on the end surface of the Z-cut LiTaO3 single crystal by plasma enhanced chemical vapor deposition.

9. The high-sensitivity, wide-range piezoelectric pressure sensor according to claim 1, characterized in that: The axis of the connector (3) is parallel to the wafer (21), and the tubular joint (31) is provided with an external thread.

10. The high-sensitivity, wide-range piezoelectric pressure sensor according to claim 1, characterized in that: The central axis (32) is electrically connected to the electrode sheet (22) via a wire (4).

Images