Miniaturized quartz piezoelectric resonant mechanical sensor

Abstract

The utility model relates to a miniaturized quartz piezoelectric resonant mechanical sensor, which comprises a flexible substrate, a miniaturized sensing unit and a processing IC, the upper end and the lower end of the flexible substrate are respectively provided with the processing IC and the miniaturized sensing unit, the miniaturized sensing unit comprises a cover plate, a rigid supporting body and a quartz chip, the rigid supporting body is provided with a cavity, and the quartz chip is arranged in the cavity. A circle of step structure is arranged at the lower port of the cavity along the edge, a quartz chip is installed on the step structure and communicated with the processing IC, and a cover plate covering the quartz chip is installed at the bottom of the rigid bearing body. According to the utility model, the quartz chip is arranged inside the miniaturized sensing unit, and the rigid carrier is used as a bearing unit of the quartz frequency chip, so that the quartz frequency chip can be in mechanical contact with the outside to transfer mechanical energy, and the mechanical energy is concentrated to the center of the quartz chip, so that the basic frequency is changed, and the generated frequency difference value is gradually increased; and a linear relation is formed with an external mechanical increment, so that a mechanical sensing effect is achieved.

Description

Technical Field

[0001] This utility model relates to the field of contact mechanical sensor technology, and in particular to a micro-quartz piezoelectric resonant mechanical sensor. Background Technology

[0002] Traditional mechanical sensors are broadly categorized into contact and non-contact types, such as contact strain gauge sensors and non-contact inertial sensors. In applications of traditional contact strain gauge sensors, space constraints related to mechanical components necessitate miniaturizing the strain gauge to the millimeter level. Traditional strain gauge sensors use a sensitive grid as the sensing element. When miniaturizing the sensor from over 10mm to approximately 1mm, the sensitive grid size also shrinks, requiring a further reduction in linewidth to the tens of micrometers. Failure to meet linewidth and consistency requirements significantly impacts the sensor's accuracy, sensitivity, response time, and range, hindering its functionality at larger sizes and drastically increasing manufacturing costs and precision requirements. Furthermore, traditional strain gauge mechanical sensors often utilize flexible substrate materials. When miniaturized to the millimeter level, installation difficulties, such as adhesion problems or even peeling, arise during connection to the object being measured.

[0003] Therefore, inventing a miniaturized mechanical sensor that can meet multiple functional requirements will be a key factor in the development of the next generation of contact mechanical sensors. Summary of the Invention

[0004] The technical problem to be solved by this utility model is to provide a miniaturized quartz piezoelectric resonant mechanical sensor. It uses the thickness shear oscillation of AT-cut quartz crystal as the main sensing vibration mode. A miniaturized sensing unit is formed by using a rigid support to carry the quartz chip. When an external force is transmitted to the quartz chip through both sides of the rigid support, the quartz chip will generate stress deformation, which will cause a change in the resonant frequency. The stress magnitude is determined by a fixed stress-frequency linear relationship, thereby realizing the sensor function.

[0005] The technical solution adopted by this utility model to solve its technical problem is as follows: a miniaturized quartz piezoelectric resonant mechanical sensor is provided, including a flexible substrate, a miniaturized sensing unit and a processing IC. The processing IC and the miniaturized sensing unit are respectively installed at the upper and lower ends of the flexible substrate. The miniaturized sensing unit includes a cover plate, a rigid support body and a quartz chip. The rigid support body has a cavity, and a stepped structure is arranged along the edge at the lower port of the cavity. The quartz chip is installed on the stepped structure and is connected to the processing IC. The processing IC provides the processing result of the electrical signal of the quartz chip to the outside. A cover plate covering the quartz chip is installed at the bottom of the rigid support body.

[0006] As a supplement to the technical solution described in this utility model, at least four upper surface flexible electrodes are installed on the upper end of the flexible substrate, two of which are connected to the quartz chip and the processing IC respectively, and the remaining upper surface flexible electrodes are used to connect to external power supply and signal output.

[0007] As a supplement to the technical solution described in this utility model, the lower end of the flexible substrate is provided with two lower surface flexible electrodes connected to the quartz chip, and the two lower surface flexible electrodes are connected to the corresponding upper surface flexible electrodes through metal leads provided inside the flexible substrate.

[0008] As a supplement to the technical solution described in this utility model, the quartz chip is provided with an electrode coating, and the upper end of the rigid carrier is provided with two metal electrodes that are connected to the flexible electrodes on the lower surface, and the metal electrodes are in communication with the electrode coating.

[0009] As a supplement to the technical solution described in this utility model, the metal electrode and the flexible electrode on the lower surface are connected by adhesive bonding or welding.

[0010] As a supplement to the technical solution described in this utility model, the quartz chip is a cubic quartz crystal, the quartz chip is AT-cut, the thickness of the quartz chip is controlled in the range of 5um-50um, and the fundamental oscillation frequency range of the quartz chip is 1MHz-50MHz.

[0011] As a supplement to the technical solution described in this utility model, the rigid support body is made of metal or quartz, and the quartz chip is adhered to the stepped structure by conductive adhesive.

[0012] As a supplement to the technical solution described in this utility model, the processing IC is a frequency signal processing unit. The processing IC is bonded to the flexible substrate with adhesive material, and the processing IC is connected to the flexible electrode on the upper surface of the flexible substrate through metal leads.

[0013] As a supplement to the technical solution described in this utility model, the processing IC is externally covered and protected with waterproof adhesive.

[0014] As a supplement to the technical solution described in this utility model, the flexible substrate is covered onto the object to be tested with adhesive, thereby achieving both adhesion and isolation from the external environment.

[0015] Beneficial effects: This utility model relates to a miniaturized quartz piezoelectric resonant mechanical sensor, which is composed of a flexible substrate, a miniaturized sensing unit, and a control IC. The miniaturized sensing unit has a size of less than 1 mm.3 The sensor comprises a rigid support body housing a quartz frequency chip. This quartz frequency chip, including but not limited to an AT-cut type, has dimensions less than 1mm x 1mm. This allows for a reduction in the overall sensor size while achieving higher resolution, sensitivity, and response time compared to traditional strain gauge sensors of the same size. This invention utilizes the thickness shear oscillation of an AT-cut quartz crystal as the primary inductive vibration mode. A miniaturized sensing unit is formed by using a rigid support body to house the quartz chip. When external force is transmitted to the quartz chip through both ends of the rigid support body, the quartz chip undergoes stress deformation, leading to a change in the resonant frequency. The stress magnitude is determined through a fixed stress-frequency linear relationship, thus realizing the sensor function. Attached Figure Description

[0016] Figure 1 This is an exploded view of this utility model;

[0017] Figure 2 This is a schematic diagram of a typical installation and application scenario of this utility model;

[0018] Figure 3 This is a bottom view of the present invention;

[0019] Figure 4 This is a top view of the present invention;

[0020] Figure 5 This is a cross-sectional view of the miniaturized sensing unit described in this utility model;

[0021] Figure 6 This is a top view of the miniaturized sensing unit described in this utility model;

[0022] Figure 7 This is a bottom view of the miniaturized sensitive unit described in this utility model after the cover plate has been removed.

[0023] Illustration: 101 Flexible substrate, 102 Upper surface flexible electrode, 103 Lower surface flexible electrode, 104 Miniaturized sensing unit, 105 Processing IC, 106 Welding material, 107 Surface of the object under test, 108 Groove structure, 109 Waterproof adhesive, 110 Metal wire, 201 Cover plate, 202 Rigid carrier, 203 Quartz frequency chip, 204 Electrode plating, 205 Stepped structure, 206 Metal electrode. Detailed Implementation

[0024] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0025] The embodiments of this utility model relate to a miniature fossil piezoelectric resonant mechanical sensor, such as... Figure 1-7 As shown, the system includes a flexible substrate 101, a miniaturized sensing unit 104, and a processing IC 105. The processing IC 105 and the miniaturized sensing unit 104 are respectively mounted on the upper and lower ends of the flexible substrate 101. The miniaturized sensing unit 104 includes a cover plate 201, a rigid support 202, and a quartz chip 203. The rigid support 202 has a cavity, and a stepped structure 205 is arranged along the edge at the lower port of the cavity. The quartz chip 203 is mounted on the stepped structure 205 and is connected to the processing IC 105. The processing IC 105 provides the processing result of the electrical signal of the quartz chip 203 to the outside. The cover plate 201 covering the quartz chip 203 is installed at the bottom of the rigid support 202.

[0026] The rigid support 202 is mainly the support structure for the quartz chip 203. It can transfer external mechanical energy F to the central region of the quartz chip 203, making it sense the external energy and causing a change Δf in its fundamental frequency f. The sensing interface is formed by the forces on both sides of the rigid support 202, and the size of the miniaturized sensing unit 104 is less than 1 mm. 3 .

[0027] The flexible substrate 101 has at least four upper surface flexible electrodes 102 mounted on its upper end. Two of the upper surface flexible electrodes 102 are connected to the quartz chip 203 and the processing IC 105, respectively, and the remaining upper surface flexible electrodes 102 are used to connect to external power supply and signal output.

[0028] The flexible substrate 101 has two lower surface flexible electrodes 103 connected to the quartz chip 203 at its lower end. The two lower surface flexible electrodes 103 are connected to the corresponding upper surface flexible electrodes 102 through metal leads provided inside the flexible substrate 101.

[0029] The quartz chip 203 is provided with an electrode plating layer 204. The rigid carrier 202 is provided with two metal electrodes 206 at its upper end, which are connected one-to-one with the flexible electrode 103 on the lower surface. The metal electrodes 206 are conductive to the electrode plating layer 204. The metal electrodes 206 and the flexible electrode 103 on the lower surface are bonded or welded together with conductive adhesive.

[0030] The quartz chip 203 is a cubic quartz crystal, which is AT-cut. The thickness of the quartz chip 203 is controlled within the range of 5um-50um, and the fundamental oscillation frequency range of the quartz chip 203 is 1MHz-50MHz.

[0031] The rigid support 202 is made of metal or quartz, and the quartz chip 203 is adhered to the stepped structure 205 by conductive adhesive.

[0032] Miniature quartz piezoelectric resonant mechanical sensors are high-sensitivity mechanical sensors based on the resonant characteristics of quartz crystals. These rigid objects, ranging in size from millimeters, are used in mechanical measurement fields, including pressure, stress, acceleration, and mass detection. Utilizing the piezoelectric and inverse piezoelectric effects and highly stable, interference-resistant resonant characteristics of quartz crystals, miniature quartz resonant mechanical sensors feature high sensitivity, low power consumption, and long-term stability. They can be installed in minute spaces and applied to multi-dimensional mechanical sensing scenarios.

[0033] This invention uses an adhesive to bond a quartz chip 203 to a rigid support 202. The quartz chip 203 provides a fundamental oscillation frequency f, has a thickness ranging from 5-50 μm, and a fundamental oscillation frequency range of 1 MHz-50 MHz. A cover plate 201 is used to enclose the quartz chip 203. The cover plate 201 and the rigid support 202 are connected and fixed by adhesive or welding, forming a structure as shown in the figure. Figure 5 The miniaturized sensing unit 104 shown has a size of less than 1 mm. 3 After the miniaturized sensing unit 104 is fabricated, the metal electrode 206 above the miniaturized sensing unit 104 is connected to the lower surface electrode 103 of the flexible substrate 101 to achieve the functions of fixation, power supply and electrical signal transmission.

[0034] An IC 105 is bonded to the top of the flexible substrate 101 with adhesive. The IC 105 is a frequency signal processing unit that includes functions such as frequency multiplication, frequency division, and filtering. The IC 105 is connected to the flexible electrode 102 on the upper surface of the flexible substrate 101 via metal leads 110. The IC 105 is also covered and protected with waterproof adhesive 109.

[0035] External mechanical energy, after being applied in both directions by the miniaturized sensing unit 104, can be transferred to the internal quartz chip 203, causing its fundamental frequency f to oscillate with a frequency change Δf. This frequency change is transmitted to the processing IC 105 through a conduction circuit, and after calculation, is output to achieve the purpose of mechanical sensing. Figure 2As shown in a typical installation application scenario, the flexible substrate 101 can be attached to the surface of the object under test 107 using adhesive material to achieve the functions of fixing and isolating the external environment. The surface of the object under test 107 has a groove structure 108, which is used to accommodate the miniaturized sensing unit 104. The two sides of the miniaturized sensing unit 104 are bonded to the inner wall of the groove structure 108 using welding material 106 to play the role of external mechanical energy transfer.

[0036] Miniaturized quartz resonant mechanical sensors are high-sensitivity mechanical sensors based on the resonant characteristics of quartz piezoelectric crystals. They utilize the resonant frequencies generated by the piezoelectric and inverse piezoelectric effects of quartz crystals for sensing, and feature high sensitivity, low power consumption, and long-term stability. The key technologies for miniaturized quartz resonant mechanical sensors lie in the miniaturization of quartz crystal chips, the miniaturization of the mechanical support, and the assembly technology of the miniaturized package.

[0037] A miniature quartz resonant mechanical sensor was developed using an AT-cut quartz crystal as the resonant frequency source and a rigid support 202 as the quartz crystal support unit. The rigid support 202 can come into contact with external forces to transfer and concentrate mechanical energy to the center of the quartz crystal 203, thereby achieving the highest detection effect. When external force is transmitted through the rigid support 202 and concentrated on the quartz crystal 203, its fundamental frequency will change based on the piezoelectric effect of quartz material. As the external force increases or decreases, the resulting frequency difference gradually increases or decreases, forming a linear relationship with the change of external force, thereby achieving the mechanical sensing effect.

[0038] This invention proposes the design of a miniaturized mechanical sensor using a piezoelectric resonance method. A quartz crystal (203) is used as the sensor's sensing element. Utilizing the inverse piezoelectric effect of the quartz crystal, high-frequency mechanical vibrations of tens of megahertz are generated, providing a stable frequency signal source. Simultaneously, the influence of stress on the frequency can be detected. Commonly used AT-cut thickness shear modes in quartz resonant crystals exhibit weak coupling with other parasitic oscillation modes. The thickness shear mode is also more likely to concentrate energy, enabling high-precision detection.

[0039] In the description of this utility model, it should be understood that the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms 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, and therefore should not be construed as a limitation on the scope of protection of this utility model. The directional terms "inner" and "outer" refer to the inner and outer contours of each component itself.

[0040] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0041] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0042] The foregoing has provided a detailed description of a miniature quartz piezoelectric resonant mechanical sensor provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A miniaturized quartz piezoelectric resonant mechanical sensor, comprising a flexible substrate (101), a miniaturized sensing unit (104), and a processing IC (105), characterized in that: The flexible substrate (101) is equipped with a processing IC (105) and a miniaturized sensing unit (104) at its upper and lower ends, respectively. The miniaturized sensing unit (104) includes a cover plate (201), a rigid support (202), and a quartz chip (203). The rigid support (202) has a cavity, and a stepped structure (205) is arranged along the edge at the lower port of the cavity. The quartz chip (203) is mounted on the stepped structure (205) and is connected to the processing IC (105). The processing IC (105) provides the processing result of the electrical signal of the quartz chip (203) to the outside. The bottom of the rigid support (202) is equipped with a cover plate (201) covering the quartz chip (203).

2. The miniature quartz piezoelectric resonant mechanical sensor according to claim 1, characterized in that: The flexible substrate (101) is equipped with at least four upper surface flexible electrodes (102), two of which are connected to the quartz chip (203) and the processing IC (105) respectively, and the remaining upper surface flexible electrodes (102) are used to connect to external power supply and signal output.

3. The miniature quartz piezoelectric resonant mechanical sensor according to claim 2, characterized in that: The flexible substrate (101) has two lower surface flexible electrodes (103) connected to the quartz chip (203) at its lower end. The two lower surface flexible electrodes (103) are connected to the corresponding upper surface flexible electrodes (102) through metal leads provided inside the flexible substrate (101).

4. The miniature quartz piezoelectric resonant mechanical sensor according to claim 2, characterized in that: The quartz chip (203) is provided with an electrode plating layer (204), and the rigid support (202) is provided with two metal electrodes (206) at the upper end, which are connected one-to-one with the flexible electrode (103) on the lower surface. The metal electrodes (206) are in communication with the electrode plating layer (204).

5. A miniature fossil piezoelectric resonant mechanical sensor according to claim 4, characterized in that: The metal electrode (206) and the lower surface flexible electrode (103) are bonded or welded together using conductive adhesive.

6. The miniature quartz piezoelectric resonant mechanical sensor according to claim 1, characterized in that: The quartz chip (203) is a cubic quartz crystal. The quartz chip (203) is AT-cut. The thickness of the quartz chip (203) is controlled within the range of 5um-50um. The fundamental oscillation frequency range of the quartz chip (203) is 1MHz-50MHz.

7. A miniature fossil piezoelectric resonant mechanical sensor according to claim 1, characterized in that: The rigid support (202) is made of metal or quartz, and the quartz chip (203) is adhered to the stepped structure (205) by conductive adhesive.

8. A miniature fossil piezoelectric resonant mechanical sensor according to claim 1, characterized in that: The processing IC (105) is a frequency signal processing unit. The processing IC (105) is bonded to the flexible substrate (101) with adhesive. The processing IC (105) is connected to the flexible electrode (102) on the upper surface of the flexible substrate (101) through metal leads (110).

9. A miniature fossil piezoelectric resonant mechanical sensor according to claim 1, characterized in that: The processing IC (105) is protected by a waterproof adhesive (109).

10. A miniature quartz piezoelectric resonant mechanical sensor according to claim 1, characterized in that: The flexible substrate (101) is covered onto the object to be tested (107) with adhesive.

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