HBAR-based micro-displacement detector, detection method and keyboard
By using a micro-displacement detector based on HBAR, the thickness or equivalent thickness of the piezoelectric material is changed by extrusion blocks, and combined with natural frequency detection, the problem of low energy consumption and low cost detection of piezoelectric ceramic materials in the field of precision displacement control is solved, and the accurate detection of micro-displacements in micro-spaces is realized.
Patent Information
- Application Number
- CN202511334095.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-18
- Publication Date
- 2025-12-30
AI Technical Summary
Existing piezoelectric ceramic materials cannot achieve low-energy, low-cost micro-displacement detection in the field of precision displacement control due to their hysteresis and creep characteristics, and traditional micro-displacement detectors are difficult to achieve accurate detection in small spaces.
A micro-displacement detector based on HBAR is used. The thickness or equivalent thickness of the piezoelectric element of the HBAR micro-displacement detector body is changed by the extrusion block on the lead axis. Combined with the natural frequency detection method, the thickness or equivalent thickness of the piezoelectric element is calculated to estimate the displacement.
It achieves low-energy and low-cost micro-displacement detection, meeting the need for accurate detection of micro-displacements in small spaces, and avoiding the high energy consumption and cost problems of traditional detectors.
Smart Images
Figure CN121230601A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of displacement measurement technology, and in particular to a micro-displacement detector, detection method and keyboard based on HBAR. Background Technology
[0002] A piezoelectric micro-displacement detector is a detector based on the fact that the natural frequency of a filter changes with the thickness of an equivalent piezoelectric material. The change in the filter's natural frequency with the thickness of the equivalent piezoelectric material means that changes in the thickness of the filter's sandwich structure will cause a change in the filter's natural frequency. This change in natural frequency, or frequency drift, can be detected by passively transmitting and receiving signals to monitor the change in the thickness of the sandwich structure.
[0003] Piezoelectric ceramic materials possess advantages such as high resolution, high response frequency, and high thrust, and are widely used in aerospace, semiconductor, bioengineering, precision testing, and precision machining. However, due to the hysteresis and creep properties of piezoelectric ceramics, they cannot be used in open-loop applications for precision displacement control or various ultra-precision platforms.
[0004] Therefore, there is an urgent need to provide a novel micro-displacement detector, detection method, and keyboard based on HBAR (High Overtone Bulk Acoustic Resonator) to solve the aforementioned technical problems in the prior art. Summary of the Invention
[0005] One objective of this invention is to provide a micro-displacement detector based on HBAR, which can detect the micro-displacement of an object's motion with low energy consumption and low detection cost, thus meeting the need for accurate detection of micro-displacements in a small space.
[0006] To achieve this objective, the present invention adopts the following technical solution:
[0007] The HBAR-based micro-displacement detector includes a lead shaft and an HBAR micro-displacement detector body. A pressing block is provided on the circumferential sidewall of the lead shaft, and the pressing block extends along the axial direction of the lead shaft. The HBAR micro-displacement detector body is located below the lead shaft and on the outer periphery of the projection of the lead shaft along its own axial direction. The pressing block can move along the axial direction of the lead shaft to contact different positions of the HBAR micro-displacement detector body and change the thickness of the piezoelectric element or the equivalent thickness of the piezoelectric element of the HBAR micro-displacement detector body.
[0008] Optionally, the extrusion block is made of insulating material, the longitudinal section of the extrusion block is triangular, the distance between the side wall of the extrusion block away from the lead axis in the horizontal direction and the circumferential side wall of the lead axis gradually decreases from top to bottom in the vertical direction, and the extrusion block can extrude and change the thickness of the piezoelectric body of the HBAR micro-displacement detector body.
[0009] Optionally, the distance between the horizontal sidewall of the extrusion block near the lead shaft and the circumferential sidewall of the lead shaft remains constant from top to bottom in the vertical direction.
[0010] Optionally, the extrusion block is made of the same material as the electrode body of the HBAR micro-displacement detector body. The longitudinal section of the extrusion block is triangular. The distance between the side wall of the extrusion block near the lead axis in the horizontal direction and the circumferential side wall of the lead axis gradually increases from top to bottom in the vertical direction. The distance between the side wall of the extrusion block away from the lead axis in the horizontal direction and the circumferential side wall of the lead axis remains unchanged from top to bottom in the vertical direction. The side wall of the extrusion block away from the lead axis in the horizontal direction can contact the electrode body and change the equivalent thickness of the piezoelectric body.
[0011] Optionally, the HBAR-based micro-displacement detector further includes an upper cover and a lower base. The upper cover covers the upper opening of the lower base, the upper cover is fixed with the lead shaft, and the lower base is fixed with the HBAR micro-displacement detector body.
[0012] Optionally, the lower base is further provided with a guide tube on its inner bottom wall, and the bottom of the guide shaft is inserted into the guide tube.
[0013] Optionally, an elastic element is provided inside the aforementioned guide tube, with one end of the elastic element connected to the bottom of the aforementioned guide shaft and the other end connected to the inner bottom wall of the aforementioned lower base.
[0014] Optionally, a first guide shaft is provided on the inner bottom wall of the lower base and inside the guide tube, and a second guide shaft is provided at the bottom of the guide shaft. The elastic element is a spring, and the two ends of the spring are respectively inserted into the first guide shaft and the second guide shaft.
[0015] Another object of the present invention is to provide a micro-displacement detection method based on HBAR, which uses an HBAR-based micro-displacement detector as described in any of the above embodiments, and includes the steps of: S1, energizing the HBAR micro-displacement detector body and continuously detecting the natural frequency f of the piezoelectric element of the HBAR micro-displacement detector body. nS2. Drive the lead shaft to move so that the extrusion block contacts different positions of the HBAR micro-displacement detector body, and change the thickness of the piezoelectric element or the equivalent thickness of the piezoelectric element of the HBAR micro-displacement detector body; S3. Detect the natural frequency f of the HBAR micro-displacement detector body after the lead shaft displacement. n S4, among which and
[0016] v is the sound velocity in the piezoelectric material, h is the thickness of the piezoelectric body or the equivalent thickness of the piezoelectric body, n is the harmonic order, C33 is the longitudinal elastic stiffness constant, and ρ is the material density. The lead axis displacement can be obtained by calculating the thickness h of the piezoelectric body or the equivalent thickness h of the piezoelectric body using the above formula.
[0017] Another object of the present invention is to provide a keyboard comprising keycaps and an HBAR-based micro-displacement detector as described in any of the above embodiments, wherein the keycaps are mounted on top of the lead shaft.
[0018] Beneficial effects:
[0019] This HBAR-based micro-displacement detector includes a lead axis and an HBAR micro-displacement detector body. A pressing block is disposed on the circumferential sidewall of the lead axis. As the lead axis moves, the pressing block contacts the piezoelectric element of the HBAR micro-displacement detector body, thereby changing the thickness or equivalent thickness of the piezoelectric element. Different positions of the pressing block correspond to different thicknesses or equivalent thicknesses of the piezoelectric element. By applying electricity to the HBAR micro-displacement detector body and detecting the natural frequency of the piezoelectric element, the thickness or equivalent thickness of the piezoelectric element can be calculated, and thus the position and displacement of the pressing block can be deduced. This HBAR-based micro-displacement detector can detect the micro-displacement of moving objects with low energy consumption and low detection cost, meeting the need for accurate detection of micro-displacements in small spaces. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of a micro-displacement detector based on HBAR provided in a specific embodiment of the present invention;
[0021] Figure 2 This is a schematic diagram of the HBAR micro-displacement detector body provided in a specific embodiment of the present invention;
[0022] Figure 3 This is a schematic diagram of the squeezing block contacting the HBAR micro-displacement detector body in Embodiment 1 provided by the specific embodiments of the present invention;
[0023] Figure 4This is a schematic diagram of the squeezing block contacting the HBAR micro-displacement detector body in Embodiment 2 provided by the specific implementation of the present invention.
[0024] In the picture:
[0025] 10. Lead shaft; 11. Second guide shaft; 20. Extrusion block; 30. HBAR micro-displacement detector body; 31. Piezoelectric element; 32. Electrode body; 40. Top cover; 50. Lower base; 51. Lead tube; 52. Elastic element; 53. First guide shaft; 60. Keycap. Detailed Implementation
[0026] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.
[0027] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0028] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0029] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.
[0030] like Figure 1 and Figure 2 As shown, this embodiment first provides a micro-displacement detector based on HBAR, including a lead axis 10 and an HBAR micro-displacement detector body 30. The circumferential sidewall of the lead axis 10 is provided with a pressing block 20, which extends along the axial direction of the lead axis 10. The HBAR micro-displacement detector body 30 is disposed below the lead axis 10 and located on the outer periphery of the projection of the lead axis 10 along its own axial direction. The pressing block 20 can move along the axial direction of the lead axis 10 to contact different positions of the HBAR micro-displacement detector body 30 and change the thickness of the piezoelectric element 31 or the equivalent thickness of the piezoelectric element 31 of the HBAR micro-displacement detector body 30.
[0031] This HBAR-based micro-displacement detector includes a lead shaft 10 and an HBAR micro-displacement detector body 30. A pressing block 20 is disposed on the circumferential sidewall of the lead shaft 10. As the lead shaft 10 moves, the pressing block 20 contacts the piezoelectric element 31 of the HBAR micro-displacement detector body 30, thereby changing the thickness or equivalent thickness of the piezoelectric element 31. Different positions of the pressing block 20 correspond to different thicknesses or equivalent thicknesses of the piezoelectric element 31. When the HBAR micro-displacement detector body 30 is energized and the natural frequency of the piezoelectric element 31 is detected, the thickness or equivalent thickness of the piezoelectric element 31 can be calculated, and the position and displacement of the pressing block 20 can be deduced. This HBAR-based micro-displacement detector can detect the micro-displacement of an object with low energy consumption and low detection cost, meeting the need for accurate detection of micro-displacements in small spaces.
[0032] Furthermore, the aforementioned HBAR-based micro-displacement detector also includes an upper cover 40 and a lower base 50. The upper cover 40 covers the upper opening of the lower base 50, and the upper cover 40 is fixedly equipped with the lead shaft 10. The lower base 50 contains the HBAR micro-displacement detector body 30. The upper cover 40 covering the upper opening of the lower base 50 allows the upper cover 40 and the lower base 50 to form a semi-closed space, shielding and protecting the HBAR micro-displacement detector body 30 inside the lower base 50, preventing damage and impact to the HBAR micro-displacement detector body 30, and improving the reliability and accuracy of the detection process.
[0033] In this embodiment, a guide tube 51 is also provided on the inner bottom wall of the lower base 50, and the bottom of the guide shaft 10 is inserted into the guide tube 51. The guide tube 51 can limit the bottom of the guide shaft 10, ensuring that the guide shaft 10 can always move along its own axial direction, improving the stability of its movement, avoiding non-axial shaking, and improving the accuracy of displacement detection.
[0034] Optionally, an elastic element 52 is provided inside the guide tube 51. One end of the elastic element 52 is connected to the bottom of the guide shaft 10, and the other end is connected to the inner bottom wall of the lower base 50. The elastic element 52 can slow down the movement speed of the guide shaft 10, buffer its movement, ensure the movement stability of the guide shaft 10, extend the detection time, and further improve the stability of displacement detection.
[0035] Specifically, a first guide shaft 53 is provided on the inner bottom wall of the lower base 50 and inside the guide tube 51, and a second guide shaft 11 is provided at the bottom of the guide shaft 10. The elastic element 52 is a spring, and the two ends of the spring are correspondingly inserted into the first guide shaft 53 and the second guide shaft 11. The arrangement of the first guide shaft 53 and the second guide shaft 11 can limit and fix the elastic element 52 when it is compressed, which not only prevents the elastic element 52 from falling off, but also improves the stability of the axial compression of the elastic element 52, prevents the elastic element 52 from shifting non-axially, and improves the stability and accuracy of the detection.
[0036] As an optional embodiment, the spring can also be replaced with a damping guide rail, so that the bottom of the lead shaft 10 is in damped sliding connection with the inside of the lead tube 51, which will not be described in detail here.
[0037] like Figure 2 As shown, this embodiment also provides the fabrication process flow of the HBAR micro-displacement detector body 30:
[0038] (1) Using a silicon wafer as a substrate, an aluminum nitride seed layer is sputtered on the surface of the substrate;
[0039] (2) Molybdenum is deposited on the aluminum nitride seed layer as the bottom electrode, and the bottom electrode is patterned by etching;
[0040] (3) Deposit a piezoelectric layer on the bottom electrode and the seed layer, pattern the piezoelectric layer, etch through holes, and expose the bottom electrode;
[0041] (4) Molybdenum is deposited as the top electrode at the bottom electrode via and on the via wall in the piezoelectric layer, and the top electrode is patterned by etching.
[0042] (5) A passivation layer is deposited on the patterned top electrode and the exposed piezoelectric layer, and the passivation layer is patterned to expose the electrode interfaces on both sides; finally, a potential connection line is deposited on the exposed electrode interfaces on both sides using a peel-and-strip process to obtain the required electrode body 32.
[0043] Example 1
[0044] like Figure 3As shown, the extrusion block 20 is made of insulating material. The longitudinal section of the extrusion block 20 is triangular. The distance between the horizontal sidewall of the extrusion block 20 away from the lead axis 10 and the circumferential sidewall of the lead axis 10 gradually decreases vertically from top to bottom. The extrusion block 20 can compress and change the thickness of the piezoelectric element 31 of the HBAR micro-displacement detector body 30. Here, the horizontal direction refers to the radial direction of the lead axis 10, and the vertical direction refers to the axial direction of the lead axis 10. That is, during the axial movement of the extrusion block 20 along the lead axis 10, its sidewall away from the lead axis 10 can compress the piezoelectric element 31. The greater the moving distance, the greater the compression of the piezoelectric element 31, and the smaller its thickness, thus changing the density of the piezoelectric element 31 and consequently altering its natural frequency. By detecting the natural frequency, the compression of the piezoelectric element 31 and the displacement of the lead axis 10 can be obtained, which will not be elaborated further here.
[0045] Optionally, the distance between the horizontal sidewall of the extrusion block 20 closest to the guide shaft 10 and the circumferential sidewall of the guide shaft 10 remains constant vertically from top to bottom. This arrangement ensures that when the extrusion block 20 is installed with the guide shaft 10, the dimensional change between the sidewall of the extrusion block 20 furthest from the guide shaft 10 and the circumferential sidewall of the guide shaft 10 is equivalent to the dimensional change of the extrusion block 20, which will not be elaborated further here.
[0046] The insulating material selected here is SiO2, which has a good insulating effect, and will not be elaborated further here.
[0047] Example 2
[0048] The difference between Embodiment 2 and Embodiment 1 is that the extrusion block 20 is made of a conductive metallic material, that is, it is made of the same material as the electrode body 32 of the HBAR micro-displacement detector body 30. The longitudinal section of the extrusion block 20 is triangular. The distance between the side wall of the extrusion block 20 closest to the lead axis 10 in the horizontal direction and the circumferential side wall of the lead axis 10 gradually increases from top to bottom in the vertical direction. The distance between the side wall of the extrusion block 20 furthest from the lead axis 10 in the horizontal direction and the circumferential side wall of the lead axis 10 remains constant from top to bottom in the vertical direction. The side wall of the extrusion block 20 furthest from the lead axis 10 in the horizontal direction can contact the electrode body 32 and change the equivalent thickness of the piezoelectric body 31. The horizontal direction mentioned here is the radial direction of the lead axis 10, and the vertical direction is the axial direction of the lead axis 10. That is, during the movement of the extrusion block 20 along the axial direction of the lead axis 10, the sidewall of the end away from the lead axis 10 is always in contact with the piezoelectric body 31 and the electrode body 32, thereby changing the thickness of the top electrode of the electrode body 32 during the movement. Since the lateral dimension of the extrusion block 20 gradually decreases from top to bottom along the axial direction of the guide shaft, the greater its moving distance, the greater the sum of the lateral dimensions of the piezoelectric body 31 and the extrusion block 20, which increases the equivalent thickness of the piezoelectric body 31 and thus changes its natural frequency. By detecting the natural frequency, the equivalent thickness of the piezoelectric body 31 and the displacement of the lead axis 10 can be obtained, which will not be elaborated here.
[0049] The conductive metallic material described here is the same as the material of the electrode body 32 of the HBAR micro-displacement detector body 30, which is molybdenum (Mo), and will not be described in detail here.
[0050] This embodiment also provides a micro-displacement detection method based on HBAR. This HBAR-based micro-displacement detection method uses an HBAR-based micro-displacement detector as described in any of the above schemes, and includes the following steps: S1, energizing the HBAR micro-displacement detector body 30 and continuously detecting the natural frequency f of the piezoelectric element 31 of the HBAR micro-displacement detector body 30. n S2. Drive the lead shaft 10 to move so that the extrusion block 20 contacts different positions of the HBAR micro-displacement detector body 30, and change the thickness of the piezoelectric element 31 or the equivalent thickness of the piezoelectric element 31 of the HBAR micro-displacement detector body 30; S3. Detect the natural frequency f of the HBAR micro-displacement detector body after the lead shaft displacement. n S4, among which and v is the sound velocity in the piezoelectric material, h is the thickness of the piezoelectric body 31 or the equivalent thickness of the piezoelectric body 31, n is the harmonic order, C33 is the longitudinal elastic stiffness constant, and ρ is the material density. The displacement of the lead axis 10 can be obtained by calculating the thickness h of the piezoelectric body 31 or the equivalent thickness h of the piezoelectric body 31 using the above formula.
[0051] In this embodiment, the natural frequency f of the HBAR micro-displacement detector body 30 after detecting the displacement of the lead axis 10 is measured. n The thickness change, density change, and equivalent thickness change of the piezoelectric material 31 can be calculated, and thus the displacement of the extrusion block 20 and the displacement of the lead axis 10 can be determined. This HBAR-based micro-displacement detection method can detect the micro-displacement of an object with low energy consumption and low detection cost, meeting the need for accurate detection of micro-displacements in small spaces.
[0052] This embodiment also provides a keyboard, which includes keycaps 60 and an HBAR-based micro-displacement detector as described in any of the above embodiments, wherein the keycaps 60 are mounted on the top of the lead shaft 10.
[0053] Please return to the reference. Figure 1 This keyboard uses the aforementioned HBAR-based micro-displacement detector, which has the following advantages: 1. It utilizes the characteristic that the inherent frequency of the filter changes with the thickness of the equivalent piezoelectric element 31 to achieve the effect of detecting micro-displacement using the filter; 2. Detecting keyboard micro-displacement using the filter avoids the active dependence of traditional micro-displacement detectors; 3. It utilizes the characteristic that the inherent frequency of the filter changes with the thickness of the equivalent piezoelectric element 31 and has a relatively high frequency to achieve dynamic real-time detection of micro-displacement; 4. It requires less space and is compatible with MEMS (Micro-Electro-Mechanical System) technology; 5. It avoids the high power consumption problem of traditional magnetic axis keyboards and achieves high detection sensitivity; 6. It avoids the heat generation problem of traditional magnetic axis keyboards; 7. It avoids the problem of the additional electromagnetic force affecting the keyboard feel of traditional magnetic axis keyboards; 8. Detecting keyboard micro-displacement using the filter is less expensive than traditional magnetic axis keyboards.
[0054] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A micro-displacement detector based on HBAR, characterized in that, The application relates to a HBAR micro-displacement detector, which comprises the following parts: a lead screw (10), a circumferential side wall of the lead screw (10) is provided with an extrusion block (20) arranged along the axial extension of the lead screw (10); a HBAR micro-displacement detector body (30) arranged below the lead screw (10) and located at the outer periphery of the projection of the lead screw (10) along the axial direction of the lead screw (10); wherein the extrusion block (20) can move along the axial direction of the lead screw (10) to make the extrusion block (20) contact different positions of the HBAR micro-displacement detector body (30) and change the thickness of a piezoelectric body (31) of the HBAR micro-displacement detector body (30) or the equivalent thickness of the piezoelectric body (31).
2. The HBAR-based micro-displacement detector of claim 1, wherein, The extrusion block (20) is made of insulating material, the longitudinal section of the extrusion block (20) is triangular, the distance between the end side wall of the extrusion block (20) away from the lead screw (10) and the circumferential side wall of the lead screw (10) gradually decreases from top to bottom along the vertical direction, and the extrusion block (20) can extrude and change the thickness of the piezoelectric body (31) of the HBAR micro-displacement detector body (30).
3. The HBAR-based micro-displacement detector of claim 2, wherein, The distance between the end side wall of the extrusion block (20) close to the lead screw (10) and the circumferential side wall of the lead screw (10) remains unchanged from top to bottom along the vertical direction.
4. The HBAR-based micro-displacement detector of claim 1, wherein, The extrusion block (20) is made of the same material as the electrode body (32) of the HBAR micro-displacement detector body (30), the longitudinal section of the extrusion block (20) is triangular, the distance between the end side wall of the extrusion block (20) close to the lead screw (10) and the circumferential side wall of the lead screw (10) gradually increases from top to bottom along the vertical direction, the distance between the end side wall of the extrusion block (20) away from the lead screw (10) and the circumferential side wall of the lead screw (10) remains unchanged from top to bottom along the vertical direction, and the end side wall of the extrusion block (20) away from the lead screw (10) can contact the electrode body (32) and change the equivalent thickness of the piezoelectric body (31).
5. The HBAR-based micro-displacement detector of claim 1, wherein, The HBAR-based micro-displacement detector further comprises an upper cover (40) and a lower base (50), the upper cover (40) covers the upper opening of the lower base (50), the upper cover (40) is fixedly provided with the lead screw (10), and the lower base (50) is fixedly provided with the HBAR micro-displacement detector body (30) inside.
6. The HBAR-based micro-displacement detector of claim 5, wherein, The inner bottom wall of the lower base (50) is further provided with a lead pipe (51), and the bottom of the lead screw (10) is inserted into the lead pipe (51).
7. The HBAR-based micro-displacement detector of claim 6, wherein, The lead pipe (51) is provided with an elastic member (52), one end of the elastic member (52) is connected to the bottom of the lead screw (10), and the other end is connected to the inner bottom wall of the lower base (50).
8. The HBAR-based micro-displacement detector of claim 7, wherein, The inner bottom wall of the lower base (50) and located inside the lead pipe (51) is provided with a first guide shaft (53), the bottom of the lead shaft (10) is provided with a second guide shaft (11), the elastic member (52) is a spring, and the two ends of the spring are correspondingly inserted into the first guide shaft (53) and the second guide shaft (11).
9. A micro-displacement detection method based on HBAR, characterized in that, Using the HBAR-based micro-displacement detector according to any one of claims 1-8, comprising the steps of: S1, energize the HBAR micro-displacement detector body (30) and continuously detect the natural frequency f of the piezoelectric body (31) of the HBAR micro-displacement detector body (30) n ; S2, pushing the lead shaft (10) to move so that the extrusion block (20) contacts different positions of the HBAR micro-displacement detector body (30) and changes the thickness of the piezoelectric body (31) or the equivalent thickness of the piezoelectric body (31) of the HBAR micro-displacement detector body (30); S3, detecting the natural frequency f of the HBAR micro-displacement detector body (30) after displacement of the lead screw (10) n ; S4. wherein and v is the speed of sound in the piezoelectric material, h is the thickness of the piezoelectric body (31) or the equivalent thickness of the piezoelectric body (31), n is the harmonic order, C33 is the longitudinal elastic stiffness constant, and p is the material density; the lead screw (10) displacement is obtained by calculating the thickness h of the piezoelectric body (31) or the equivalent thickness h of the piezoelectric body (31) using the above formula.
10. A keyboard characterized by The keycap (60) is installed on the top of the lead shaft (10). The keycap (60) is installed on the top of the lead shaft (10).