MEMS gyroscope based on plane sensitive structure

Abstract

According to the gyroscope, a detection beam in a second direction is adopted to realize vibration in a first direction, the vibration in the first direction is coupled with an angular velocity in a third direction to generate a Coriolis force in the second direction, and the detection beam is directly connected with a driving beam, so that the Coriolis force can be directly acted on the detection beam by the beam; the attenuation in the transmission process is greatly reduced, the detection sensitivity is remarkably improved, and the overall performance is optimized.

Description

Technical Field

[0001] The invention relates to a gyroscope, belonging to the technical field of inertial measurement devices. Background Art

[0002] The quartz micromechanical gyroscope is a MEMS angular velocity sensor and one of the core components of the inertial measurement system. It can detect the angular velocity of the rotating carrier and has the advantages of small size, low price, excellent performance, and high stability. It has broad application prospects in the fields of aerospace, weapon guidance, industrial control, automotive safety, consumer electronics, etc. According to the different directions of the measured angular velocity, the current quartz micromechanical gyroscopes are mainly divided into two categories: y-axis sensitive gyroscopes and z-axis sensitive gyroscopes. Both types of micromechanical gyroscopes need to transmit the Coriolis force to the detection beam through a connecting structure. This process causes the Coriolis force to attenuate, which is not conducive to improving the detection sensitivity. Summary of the invention

[0003] The present invention provides a gyroscope, which solves the problems disclosed in the background technology.

[0004] According to one aspect of the present disclosure, a gyroscope is provided, comprising a base, wherein two sides of the base are respectively connected with a first detection beam and a second detection beam arranged along a first direction and symmetrically distributed, and the first detection beam and the second detection beam are both provided with detection electrodes; The first detection beam is connected to a first driving beam and a second driving beam that are symmetrically distributed and arranged along the second direction on both sides of the end away from the base, and the second detection beam is connected to a third driving beam and a fourth driving beam that are symmetrically distributed and arranged along the second direction on both sides of the end away from the base, and all the driving beams are provided with driving electrodes; The driving beam generates vibration in a first direction under the action of the piezoelectric effect, and the vibration in the first direction is coupled with the angular velocity in a third direction to generate a Coriolis force in a second direction; wherein the first direction, the second direction and the third direction are perpendicular to each other.

[0005] In some embodiments of the present disclosure, a driving electrode is disposed on a side of the driving beam facing the base and another side opposite to the side facing the base, and the driving electrodes on the two sides have different polarities; The polarities of the driving electrodes on the same side of the first driving beam and the second driving beam, and the third driving beam and the fourth driving beam are inconsistent; The polarities of the driving electrodes on the opposite sides of the first driving beam and the third driving beam, and the second driving beam and the fourth driving beam are consistent.

[0006] In some embodiments of the present disclosure, a proof mass is connected to an end of the driving beam away from the detection beam.

[0007] In some embodiments of the present disclosure, the driving beams are tapered driving beams, and the narrow ends of all tapered driving beams are far away from the detection beam, or the narrow ends of all tapered driving beams are connected to the detection beam.

[0008] In some embodiments of the present disclosure, a detection electrode is provided on the side where the detection beam is connected to the driving beam; A positive detection electrode is arranged on the side of the first detection beam, and a negative detection electrode is arranged on the side of the second detection beam; or, a positive detection electrode is arranged on the side of the second detection beam, and a negative detection electrode is arranged on the side of the first detection beam.

[0009] In some embodiments of the present disclosure, the length of the detection electrode on the side of the detection beam is half the length of the detection beam, and the position of the detection electrode is offset toward the base.

[0010] In some embodiments of the present disclosure, the detection beam is a rectangular detection beam.

[0011] In some embodiments of the present disclosure, a fixing block is connected to a corner of the base.

[0012] The beneficial effects achieved by the present invention are as follows: 1. The present invention adopts a detection beam in the second direction to realize vibration in the first direction. The vibration in the first direction is coupled with the angular velocity in the third direction to generate a Coriolis force in the second direction. Since the detection beam and the driving beam are directly connected, the Coriolis force can be directly applied to the detection beam, which greatly reduces the attenuation in the transmission process, significantly improves the detection sensitivity, and optimizes the overall performance; 2. The length of the detection electrode of the present invention is half the length of the detection beam, and the position of the detection electrode is offset toward the base. This design takes into account the distribution law of the surface charge during the bending process of the detection beam, which can effectively improve the output strength of the signal, enhance the measurement sensitivity, and provide a guarantee for obtaining a more accurate angular velocity signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic diagram of the structure of a gyroscope; Figure 2 is a schematic diagram of the second structure of the gyroscope; Figure 3 is a stereogram of a gyroscope; Figure 4 The driving vibration mode diagram of the gyroscope when it is working; Figure 5 This is the detected vibration mode diagram of the gyroscope when it is working. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. It is obvious that the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present disclosure and its application or use. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present disclosure.

[0015] Unless otherwise specified, the relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present disclosure.

[0016] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0017] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0018] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0019] It should be noted that similar symbols and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it does not require further discussion in subsequent figures.

[0020] At the same time, in the description of the embodiments of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance. Therefore, the features defined as "first" or "second" may explicitly or implicitly include one or more features.

[0021] Traditional gyroscopes mainly use the principle of conservation of angular momentum, so they are mainly a continuously rotating object, and the direction of their axis does not change with the rotation of the bracket that supports them. Micromechanical gyroscopes (MEMS gyroscopes) use the Coriolis force.

[0022] In order to solve the problem of Coriolis force attenuation in existing gyroscopes, the present disclosure proposes a gyroscope with a new structure. The gyroscope as a whole is a planar sensitive structure. Specifically, the detection beam and the driving beam are directly connected to reduce the attenuation of the Coriolis force during transmission.

[0023] See also Figure 1 , Figure 1Schematic diagram of the structure of the gyroscope disclosed in the present invention. The gyroscope may include a base 100 , a first detection beam 210 , a second detection beam 220 , a first driving beam 310 , a second driving beam 320 , a third driving beam 330 and a fourth driving beam 340 .

[0024] The two sides of the base 100 are respectively connected to a first detection beam 210 and a second detection beam 220 which are arranged along a first direction and are symmetrically distributed, and the first detection beam 210 and the second detection beam 220 are both covered with detection electrodes; the two sides of the end of the first detection beam 210 away from the base 100 are respectively connected to a first driving beam 310 and a second driving beam 320 which are arranged along a second direction and are symmetrically distributed, and the two sides of the end of the second detection beam 220 away from the base 100 are respectively connected to a third driving beam 330 and a fourth driving beam 340 which are arranged along the second direction and are symmetrically distributed, and all driving beams are covered with driving electrodes; the driving beam generates vibration in a first direction under the action of the piezoelectric effect, and the vibration in the first direction is coupled with the angular velocity in the third direction to generate a Coriolis force in the second direction; wherein the first direction, the second direction and the third direction are perpendicular to each other.

[0025] It should be noted that the gyroscope can be made of a Z-cut quartz wafer of a certain thickness through a laser cutting process or a wet etching process. Taking the Z-axis gyroscope as an example, the first direction can be the Y-axis direction, the second direction can be the X-axis direction, and the third direction is the Z-axis direction. In order to ensure the effectiveness and stability of the vibration, a larger driving voltage can be used to drive the driving beam to generate vibration in the Y-axis direction, but when the angular velocity in the Z-axis direction is input, the driving beam generates a Coriolis force along the X-axis direction. Since the detection beam and the driving beam are directly connected, the generated Coriolis force vibrates along the X-axis direction, driving the first detection beam 210 and the second detection beam 220 to vibrate along the X-axis direction. Due to the piezoelectric effect of the quartz crystal, the first detection beam 210 and the second detection beam 220 generate a transverse electric field, forming a differential charge on the detection electrode, and the input angular velocity can be obtained after amplification, filtering, and demodulation.

[0026] The above-mentioned gyroscope uses a detection beam in the X-axis direction to realize vibration in the first direction. The vibration in the Y-axis direction is coupled with the angular velocity in the Z-axis direction to generate a Coriolis force in the X-axis direction. Since the detection beam and the driving beam are directly connected, the Coriolis force can be directly applied to the detection beam, which greatly reduces the attenuation in the transmission process, significantly improves the detection sensitivity, and optimizes the overall performance. This design improves the detection efficiency and ensures the accuracy of the measurement results.

[0027] It should be noted that, in some embodiments, the driving beam may be a conical driving beam, and the narrow ends of all the conical driving beams are far away from the detection beam, or the narrow ends of all the conical driving beams are connected to the detection beam. Taking the Z-axis gyroscope as an example, the conical driving beam can generate a better vibration in the Y-axis direction after being driven by voltage. Of course, driving beams of other structures can also be used as long as they can ensure the generation of vibration in the Y-axis direction.

[0028] It should be noted that, in some embodiments, the detection beam may be a rectangular detection beam. This structure can sensitively detect weak Coriolis force signals, thereby improving the sensitivity of the gyroscope.

[0029] It should be noted that, in some embodiments, the base 100 can be a square block. In order to facilitate fixation, fixed blocks (i.e., 101, 102, 103, and 104 in the figure) can be connected at the corners of the square block. Specifically, fixed blocks are fixed at both ends of each diagonal, and the shape, mass, etc. of each fixed block are consistent, so that the base 100 and the fixed blocks form a centrally symmetrical structure.

[0030] Figure 2 is a schematic diagram of the second structure of the gyroscope disclosed in the present invention, which can be Figure 1 Mass blocks (i.e., 410, 420, 430, 440 in the figure) are added to the structure. Specifically, the mass blocks are connected to the end of the driving beam away from the detection beam. Each driving beam is connected to the mass blocks. The inertial mass of the driving beam can be increased by the mass blocks. Similar to the fixed blocks, the shape and mass of each mass block are consistent, so that the entire gyroscope has a symmetrical structure.

[0031] It should be noted that both the driving electrode and the detection electrode include positive electrodes and negative electrodes. The positive electrode and negative electrode of the driving electrode can be defined as the driving positive electrode and the driving negative electrode respectively, and the positive electrode and negative electrode of the detection electrode can be defined as the detection positive electrode and the detection negative electrode respectively.

[0032] In some embodiments, the driving electrodes may be covered on the side of the driving beam facing the base 100 and the other side opposite to the side facing the base 100, and the polarities of the driving electrodes on the two sides are inconsistent. At the same time, the polarities of the driving electrodes on the same side of the first driving beam 310 and the second driving beam 320, and the third driving beam 330 and the fourth driving beam 340 are inconsistent, and the polarities of the driving electrodes on the opposite sides of the first driving beam 310 and the third driving beam 330, and the second driving beam 320 and the fourth driving beam 340 are consistent.

[0033] It should be noted that, in order to ensure the driving effect, the driving electrode covers most of the side surfaces of the driving beam, and generally the coverage area is not less than 85%.

[0034] The detection electrode can be covered on the side where the detection beam connects to the driving beam; a positive detection electrode is set on the side of the first detection beam 210, and a negative detection electrode is set on the side of the second detection beam 220; or, a positive detection electrode is set on the side of the second detection beam 220, and a negative detection electrode is set on the side of the first detection beam 210.

[0035] It should be noted that in order to adapt to the characteristics of the bending deformation of the detection beam, the length of the detection electrode is half the length of the detection beam, and the position of the detection electrode is offset toward the base 100. This design fully considers the distribution law of surface charge during the bending process of the detection beam, and can effectively improve the output intensity of the signal, enhance the measurement sensitivity, and provide a guarantee for obtaining a more accurate angular velocity signal.

[0036] It should be noted that the arrangement of the above electrodes makes the driving vibration and the detection vibration both in-plane vibrations, and the detection electrode does not need to be made into separate sidewall electrodes, which reduces the process difficulty.

[0037] See also Figure 3 , an example of electrode installation is given in detail, in which the upper electrode 311 of the first driving beam, the lower electrode 322 of the second driving beam, the lower electrode 332 of the third driving beam, and the upper electrode 341 of the fourth driving beam are driving positive electrodes, the lower electrode 312 of the first driving beam, the upper electrode 321 of the second driving beam, the upper electrode 331 of the third driving beam, and the lower electrode 342 of the fourth driving beam are driving negative electrodes, the left surface electrode 211 of the first detection beam and the right surface electrode 212 of the first detection beam are detection positive electrodes, the left surface electrode 221 of the second detection beam and the right surface electrode 222 of the second detection beam are detection negative electrodes, and the driving positive and negative electrodes and the detection positive and negative electrodes are all rectangular and arranged on the side surfaces of the driving beam and the detection beam.

[0038] See also Figure 4 When periodic voltage signals with opposite phases are applied to the driving positive electrode and the driving negative electrode respectively, the inverse piezoelectric effect of quartz causes the first driving beam 310, the second driving beam 320, the third driving beam 330, and the fourth driving beam 340 to generate periodic bending vibrations in the Y-axis direction; when the frequency of the input periodic voltage signal is the same as the intrinsic frequency of the driving beam, the driving beam generates reference vibrations in the Y-axis direction.

[0039] See also Figure 5 When a reference vibration is generated in the Y-axis direction, if there is an angular velocity input in the Z-axis direction, the driving beam generates a Coriolis force along the X-axis direction and generates vibration along this direction, driving the first detection beam 210 and the second detection beam 220 to vibrate along the X-axis direction. Due to the piezoelectric effect of the quartz crystal, the first detection beam 210 and the second detection beam 220 generate a transverse electric field, and differential charges are formed on the detection positive electrode and the detection negative electrode. The input angular velocity can be obtained through amplification, filtering, and demodulation.

[0040] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A gyroscope, characterized in that: It comprises a base, wherein two sides of the base are respectively connected with a first detection beam and a second detection beam arranged along a first direction and symmetrically distributed, and both the first detection beam and the second detection beam are provided with detection electrodes; The first detection beam is connected to a first driving beam and a second driving beam that are symmetrically distributed and arranged along the second direction on both sides of the end away from the base, and the second detection beam is connected to a third driving beam and a fourth driving beam that are symmetrically distributed and arranged along the second direction on both sides of the end away from the base, and all the driving beams are provided with driving electrodes; The driving beam generates vibration in a first direction under the action of the piezoelectric effect, and the vibration in the first direction is coupled with the angular velocity in a third direction to generate a Coriolis force in a second direction; wherein the first direction, the second direction and the third direction are perpendicular to each other.

2. The gyroscope according to claim 1, characterized in that A driving electrode is disposed on a side of the driving beam facing the base and another side opposite to the side facing the base, and the polarities of the driving electrodes on the two sides are inconsistent; The polarities of the driving electrodes on the same side of the first driving beam and the second driving beam, and the third driving beam and the fourth driving beam are inconsistent; The polarities of the driving electrodes on the opposite sides of the first driving beam and the third driving beam, and the second driving beam and the fourth driving beam are consistent.

3. The gyroscope according to claim 1, characterized in that The end of the driving beam away from the detection beam is connected with a mass block.

4. The gyroscope according to any one of claims 1 to 3, characterized in that: The driving beams are tapered driving beams, and narrow ends of all tapered driving beams are far away from the detection beam, or narrow ends of all tapered driving beams are connected to the detection beam.

5. The gyroscope according to claim 1, characterized in that: A detection electrode is provided on the side where the detection beam is connected to the driving beam; A positive detection electrode is arranged on the side of the first detection beam, and a negative detection electrode is arranged on the side of the second detection beam; or, a positive detection electrode is arranged on the side of the second detection beam, and a negative detection electrode is arranged on the side of the first detection beam.

6. The gyroscope according to claim 5, characterized in that The length of the detection electrode on the side of the detection beam is half of the length of the detection beam, and the position of the detection electrode is offset toward the base.

7. The gyroscope according to claim 1, 5 or 6, characterized in that: The detection beam is a rectangular detection beam.

8. The gyroscope according to claim 1, characterized in that The corners of the base are connected with fixing blocks.

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