MEMS galvanometer, MEMS galvanometer array and radar system

Abstract

The embodiment of the invention provides an MEMS galvanometer, an MEMS galvanometer array and a radar system, and the MEMS galvanometer comprises an outer frame which is of a hollow structure; the rotating structure is located in the hollow area of the outer frame, the rotating structure comprises a reflecting mirror frame and a pair of rotating shafts connected between the reflecting mirror frame and the outer frame, and the reflecting mirror frame comprises a grounding electrode; the reflecting mirror is positioned on the reflecting mirror frame; the substrate and the outer frame form a cavity; the steering electrode group is located on the side, facing the rotating structure, of the substrate, and the steering electrode group comprises a first steering electrode and a second steering electrode which are arranged on the two sides of the pair of rotating shafts; and when the grounding electrode is parallel to the substrate, the distance between the first steering electrode and the grounding electrode is gradually reduced from the outer side to the inner side of the reflecting mirror, and the distance between the second steering electrode and the grounding electrode is gradually reduced from the outer side to the inner side of the reflecting mirror.

Description

Technical Field

[0001] The present disclosure relates to the technical field of micro-electromechanical systems, and in particular to a MEMS galvanometer, a MEMS galvanometer array and a radar system. Background Art

[0002] A MEMS (Miciro-Electro-Mechanical System) galvanometer is a tiny, drivable mirror made based on MEMS technology, and its mirror diameter is usually only a few millimeters. Compared with traditional optical scanning mirrors, MEMS galvanometers have the advantages of light weight, small size, easy mass production, and low production cost. They perform better in terms of optical, mechanical properties and power consumption. MEMS galvanometers are currently maturely used in markets such as LiDAR, high-definition projection, laser confocal microscopy systems, and AR. The movement modes of MEMS galvanometers include two mechanical movements: translation and torsion. For torsional MEMS galvanometers, when the optical deflection angle is large (reaching more than 10°), laser pointing deflection, graphical scanning, and image scanning can be achieved. Summary of the invention

[0003] The embodiments of the present disclosure provide a MEMS galvanometer, a MEMS galvanometer array, and a radar system. The specific solutions are as follows:

[0004] A MEMS galvanometer provided in an embodiment of the present disclosure includes:

[0005] An outer frame, wherein the outer frame is a hollow structure;

[0006] A rotating structure, the rotating structure is located in the hollow area of ​​the outer frame, the rotating structure includes a reflector frame and a pair of rotating shafts connected between the reflector frame and the outer frame, and the reflector frame includes a ground electrode;

[0007] A reflector, located on the reflector frame;

[0008] A base, wherein the base and the outer frame form a cavity;

[0009] A steering electrode group is located on the side of the substrate facing the rotating structure, and the steering electrode group includes a first steering electrode and a second steering electrode arranged on both sides of the pair of rotating shafts; wherein,

[0010] When the ground electrode and the substrate are parallel, the distance between the first steering electrode and the ground electrode gradually decreases from the outside to the inside of the reflector, and the distance between the second steering electrode and the ground electrode gradually decreases from the outside to the inside of the reflector.

[0011] In a possible implementation, in the above-mentioned MEMS oscillator provided in an embodiment of the present disclosure, the surface of the substrate facing the reflector is a flat surface, and the first steering electrode and the second steering electrode both include at least two step structures whose thickness gradually increases from the outside to the inside of the reflector, and each of the step structures serves as a sub-electrode.

[0012] In a possible implementation, in the above-mentioned MEMS galvanometer provided in an embodiment of the present disclosure, the substrate has at least two step structures whose thickness gradually increases from the outside to the inside of the reflector at positions corresponding to the first steering electrode and the second steering electrode, and the first steering electrode and the second steering electrode are arranged on the corresponding step structures.

[0013] In a possible implementation, in the above-mentioned MEMS galvanometer provided in an embodiment of the present disclosure, a first angle is formed between the inclined surface formed by each steering electrode and the substrate, and a second angle is formed between the reflector frame and the substrate after being twisted at the maximum angle, and the degree of the first angle is smaller than the degree of the second angle.

[0014] In a possible implementation, in the above-mentioned MEMS galvanometer provided in an embodiment of the present disclosure, the ground electrode faces the surface of the substrate and the corresponding positions of the first steering electrode and the second steering electrode have at least two step structures whose thickness gradually increases from the outside to the inside of the reflector.

[0015] In a possible implementation, in the above-mentioned MEMS galvanometer provided in an embodiment of the present disclosure, both the first steering electrode and the second steering electrode include sub-electrodes arranged corresponding to the step structure, and the thickness of each of the sub-electrodes is the same.

[0016] In a possible implementation, in the above-mentioned MEMS galvanometer provided in an embodiment of the present disclosure, there is a gap between each two adjacent sub-electrodes in the first steering electrode and the second steering electrode.

[0017] In a possible implementation, the MEMS galvanometer provided in the embodiment of the present disclosure further includes a first isolation layer disposed on the side of the steering electrode group facing the ground electrode, wherein the orthographic projection of the first isolation layer on the substrate covers the substrate and fills the gap.

[0018] In a possible implementation, in the above-mentioned MEMS galvanometer provided in an embodiment of the present disclosure, the width of each of the step structures corresponding to the first steering electrode gradually increases from the outside to the inside of the reflector, and the width of each of the step structures corresponding to the second steering electrode gradually increases from the outside to the inside of the reflector.

[0019] In a possible implementation, in the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure, the outer frame and the rotating structure are an integrated structure formed by using a silicon substrate, and the reflector frame is reused as the ground electrode.

[0020] In a possible implementation, in the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure, the pair of rotation axes are located on the same straight line and coincide with the central axis of the reflector, and the first steering electrode and the second steering electrode are symmetrically distributed on both sides of the central axis of the reflector.

[0021] In a possible implementation, in the above-mentioned MEMS oscillator provided in the embodiment of the present disclosure, the shape of the reflector is the same as the shape of the reflector frame, and the size of the reflector is the same as the size of the reflector frame.

[0022] In a possible implementation, in the above-mentioned MEMS oscillator provided in an embodiment of the present disclosure, the shape of the reflector includes a circle or an ellipse, and the rotating shaft is connected to the outer annular surface of the reflector frame.

[0023] In a possible implementation, in the above-mentioned MEMS oscillator provided in the embodiment of the present disclosure, the shape of the reflector is square, a pair of side edges of the reflector frame have a concave structure, and the rotating shaft is embedded in the concave structure and connected to the reflector frame.

[0024] In a possible implementation, the MEMS galvanometer provided in the embodiment of the present disclosure further includes: a plurality of contact electrodes arranged between the steering electrode group and the substrate and arranged one-to-one with the step structure, a first driving structure arranged between the contact electrode and the substrate and corresponding to the first steering electrode, and a second driving structure arranged between the contact electrode and the substrate and corresponding to the second steering electrode; wherein,

[0025] The first steering electrode is electrically connected to the corresponding contact electrode, and the second steering electrode is electrically connected to the corresponding contact electrode;

[0026] The contact electrodes corresponding to the first steering electrodes are electrically connected to the first driving structure, and the contact electrodes corresponding to the second steering electrodes are electrically connected to the second driving structure.

[0027] In a possible implementation, in the above-mentioned MEMS galvanometer provided in an embodiment of the present disclosure, the first driving structure includes: a first driving electrode electrically connected to each of the contact electrodes corresponding to the first steering electrode at the same time, and a first driving line electrically connected to the first driving electrode;

[0028] The second driving structure includes: a second driving electrode electrically connected to each of the contact electrodes corresponding to the second steering electrode, and a second driving line electrically connected to the second driving electrode.

[0029] In a possible implementation, in the above-mentioned MEMS galvanometer provided in an embodiment of the present disclosure, the first driving structure includes: first driving electrodes electrically connected to the contact electrodes corresponding to the first steering electrodes in a one-to-one correspondence, and first driving lines electrically connected to the first driving electrodes in a one-to-one correspondence;

[0030] The second driving structure includes: second driving electrodes electrically connected to the contact electrodes corresponding to the second steering electrodes in a one-to-one correspondence, and second driving lines electrically connected to the second driving electrodes in a one-to-one correspondence.

[0031] In a possible implementation, the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure further includes: a second isolation layer arranged between the contact electrode and the first drive structure, the second drive structure, and a third isolation layer arranged between the contact electrode and the steering electrode group; wherein the second isolation layer exposes the first drive electrode and the second drive electrode, and the third isolation layer exposes the contact electrode.

[0032] Correspondingly, an embodiment of the present disclosure further provides a MEMS galvanometer array, comprising a plurality of the above-mentioned MEMS galvanometers provided by an embodiment of the present disclosure arranged in an array.

[0033] In a possible implementation, in the above-mentioned MEMS galvanometer array provided in an embodiment of the present disclosure, the first steering electrode in each of the MEMS galvanometers corresponds to one or a plurality of first driving lines which are the same number as the step structure, and the second steering electrode in each of the MEMS galvanometers corresponds to one or a plurality of second driving lines which are the same number as the step structure, and each of the first driving lines in each of the MEMS galvanometers is electrically connected to the same first driving voltage terminal, and each of the second driving lines in each of the MEMS galvanometers is electrically connected to the same second driving voltage terminal.

[0034] In a possible implementation, in the above-mentioned MEMS galvanometer array provided in an embodiment of the present disclosure, the first steering electrode in each of the MEMS galvanometers corresponds to a plurality of first drive lines having the same number as the step structure, and the second steering electrode in each of the MEMS galvanometers corresponds to a plurality of second drive lines having the same number as the step structure; wherein,

[0035] The first driving lines corresponding to the step structures at the same position in the MEMS galvanometers are electrically connected to the same first driving voltage terminal, and the first driving lines corresponding to the step structures at different positions in the MEMS galvanometers are electrically connected to different first driving voltage terminals;

[0036] The second driving lines corresponding to the stepped structures at the same position in the MEMS galvanometers are electrically connected to the same second driving voltage terminal, and the second driving lines corresponding to the stepped structures at different positions in the MEMS galvanometers are electrically connected to different second driving voltage terminals.

[0037] Correspondingly, an embodiment of the present disclosure further provides a radar system, comprising the above-mentioned MEMS galvanometer according to an embodiment of the present disclosure, or comprising the above-mentioned MEMS galvanometer array according to an embodiment of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the corresponding transmitting and receiving system when a conventional MEMS galvanometer array is applied to a laser radar;

[0039] Figure 2 A schematic diagram of the structure of a MEMS galvanometer provided in an embodiment of the present disclosure;

[0040] Figure 3 for Figure 2 The corresponding plan view;

[0041] Figure 4 for Figure 2 Exploded schematic diagram of the corresponding structure of each layer;

[0042] Figure 5 for Figure 3 A schematic cross-sectional view of a portion of the structure along the AA' direction;

[0043] Figure 6 for Figure 5 A schematic diagram of the deflection effect of driving the MEMS galvanometer when an AC voltage is applied to the first steering electrode shown;

[0044] Figure 7 for Figure 5 A schematic diagram of the deflection effect of driving the MEMS galvanometer when an AC voltage is applied to the second steering electrode shown;

[0045] Figure 8 for Figure 4 The middle part circuit connection structure diagram;

[0046] Fig. 9 for Figure 4 The middle part circuit connection structure diagram;

[0047] Figures 10A-10FThe embodiments of the present disclosure provide Figure 2 The schematic diagram of the manufacturing process of the MEMS galvanometer shown;

[0048] Fig.11 A schematic diagram of the structure of another MEMS galvanometer provided in an embodiment of the present disclosure;

[0049] Fig.12 for Fig.11 The corresponding plan view;

[0050] Fig.13 for Fig.11 Exploded schematic diagram of the corresponding structure of each layer;

[0051] Fig.14 for Fig.12 A schematic cross-sectional view of a portion of the structure along the AA' direction;

[0052] Fig.15 for Fig.14 Schematic diagram of the deflection effect of driving the MEMS galvanometer when the first steering electrode is loaded with an AC voltage;

[0053] Fig.16 for Fig.14 Schematic diagram of the deflection effect of driving the MEMS galvanometer when the second steering electrode is loaded with an AC voltage;

[0054] Fig.17 A schematic diagram of the structure of another MEMS galvanometer provided in an embodiment of the present disclosure;

[0055] Fig.18 for Fig.17 The corresponding plan view;

[0056] Fig.19 for Fig.17 Exploded schematic diagram of the corresponding structure of each layer;

[0057] Fig. 20 for Fig.18 A schematic cross-sectional view of a portion of the structure along the AA' direction;

[0058] Fig.21 for Fig.13 A schematic cross-sectional view of a portion of the structure along the AA' direction after the first isolation layer is provided;

[0059] Figure 22A-22B For production Fig.17 Schematic diagram of the process flow of the MEMS galvanometer shown;

[0060] Fig.23 A schematic diagram of the structure of another MEMS galvanometer provided in an embodiment of the present disclosure;

[0061] Fig.24for Fig.23 The corresponding plan view;

[0062] Fig.25 for Fig.23 Exploded schematic diagram of the corresponding structure of each layer;

[0063] Fig.26 for Fig.25 The middle part circuit connection structure diagram;

[0064] Fig. 27 for Fig.25 The middle part circuit connection structure diagram;

[0065] Figure 28A-28G for Fig.23 Schematic diagram of the manufacturing process flow of the MEMS galvanometer shown;

[0066] Fig.29 An exploded schematic diagram of the structure of each layer of another MEMS galvanometer provided in an embodiment of the present disclosure;

[0067] Fig.30 for Fig.29 The middle part circuit connection structure diagram;

[0068] Fig.31 for Fig.29 The middle part circuit connection structure diagram;

[0069] Fig.32 for Fig.29 A schematic cross-sectional view of the structure in the middle;

[0070] Fig.33 A schematic diagram of the structure of another MEMS galvanometer provided in an embodiment of the present disclosure;

[0071] Fig.34 A schematic diagram of the structure of another MEMS galvanometer provided in an embodiment of the present disclosure;

[0072] Fig.35 A schematic diagram of a MEMS galvanometer array structure provided in an embodiment of the present disclosure;

[0073] Fig.36 A schematic diagram of a corresponding transmitting and receiving system when the MEMS galvanometer array provided in an embodiment of the present disclosure is applied to a laser radar;

[0074] Figure 37A-Figure 37D for Fig.35 Schematic diagram of the manufacturing process flow of the MEMS galvanometer array shown. DETAILED DESCRIPTION

[0075] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. And in the absence of conflict, the embodiments in the present disclosure and the features in the embodiments can be combined with each other. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present disclosure.

[0076] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. "Include" or "comprising" and other similar words used in the present disclosure mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and other similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Inside", "outside", "upper", "lower", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0077] It should be noted that the sizes and shapes of the figures in the accompanying drawings do not reflect the actual proportions, and are only intended to illustrate the present disclosure. The same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions.

[0078] The mirror diameter of a MEMS galvanometer is usually only a few millimeters. It is a tiny, drivable reflector made based on MEMS technology. Compared with traditional optical scanning mirrors, it has superior performance such as small size, low power consumption, and high integration. It is currently mainly used in laser radar and other fields. Figure 1 As shown, Figure 1 This is a schematic diagram of the corresponding transmitting and receiving system when a conventional MEMS galvanometer array is applied to a laser radar. The laser emitted by the laser transmitting component is reflected by ordinary reflectors and MEMS galvanometers to nearby objects (obstacles) in turn, and then Figure 1 The process shown in is fed back to the control component, and the small angle twisting of the MEMS galvanometer can enable the laser beam to scan the surface, and the image signal of the surrounding environment is obtained by processing the changes in the beam information fed back. Compared with traditional optical scanning mirrors, MEMS galvanometers obtained through micromachining technology are gradually replacing traditional optical scanning mirrors in applications such as laser radar due to their advantages such as light weight, small size, easy mass production, and low production cost.

[0079] At present, the most widely used MEMS galvanometer is driven by a flat electrode. It has a simple structure and low processing difficulty, but it requires a large driving voltage to produce adsorption through the electrostatic force between the flat electrodes, and it is easy to attract. Although the electrostatic force can be increased by reducing the distance between the flat electrodes, it will also limit the available angle range of the MEMS galvanometer.

[0080] The present disclosure provides a MEMS galvanometer, such as Figure 2-Figure 5 As shown, Figure 2 A structural diagram of a MEMS galvanometer. Figure 3 for Figure 2 The corresponding plan view is: Figure 4 for Figure 2 The corresponding exploded diagram of each layer structure, Figure 5 for Figure 3 The cross-sectional schematic diagram of the partial structure along the AA' direction, the MEMS galvanometer includes:

[0081] The outer frame 1 is a hollow structure; specifically, the outer frame 1 mainly plays a supporting role;

[0082] The rotating structure 2 is located in the hollow area of ​​the outer frame 1. The rotating structure 2 can use the hollow area of ​​the outer frame 1 to deflect, thereby realizing the deflection of the light beam; the rotating structure 2 includes a reflector frame 21 and a pair of rotating shafts 22 connected between the reflector frame 21 and the outer frame 1, that is, one end of the rotating shaft 22 is fixed to the outer frame 1, and the other end of the rotating shaft 22 is fixed to the reflector frame 21; the reflector frame 21 includes a ground electrode GND;

[0083] The reflector 3 is located on the reflector frame 21; specifically, the reflector 3 deflects in the same manner as the reflector frame 21 deflects, and the reflector 3 can reflect the laser beam emitted by the laser emitting component and project it into the corresponding scanning area;

[0084] A base 4, wherein the base 4 and the outer frame 1 form a cavity;

[0085] The steering electrode group 5 is located on the side of the substrate 4 facing the rotating structure 2, and the steering electrode group 5 includes a first steering electrode 51 and a second steering electrode 52 arranged on both sides of a pair of rotating shafts 22; specifically, a ground voltage is applied to the ground electrode GND, and an AC voltage (driving voltage) is applied to the first steering electrode 51 or the second steering electrode 52, and the reflector frame 21 and the reflector 3 are driven to deflect in a preset direction around the rotating shaft 22 through the electrostatic adsorption force generated between the ground electrode GND and the first steering electrode 51 or the ground electrode GND and the second steering electrode 52; wherein,

[0086] When the ground electrode GND is parallel to the substrate 1 , the distance between the first steering electrode 51 and the ground electrode GND gradually decreases from the outside to the inside of the reflector 3 , and the distance between the second steering electrode 52 and the ground electrode GND gradually decreases from the outside to the inside of the reflector 3 .

[0087] The above-mentioned MEMS galvanometer provided by the embodiment of the present disclosure, when the ground electrode and the substrate are parallel, by setting the distance between the first steering electrode and the ground electrode to gradually decrease from the outside to the inside of the reflector, and setting the distance between the second steering electrode and the ground electrode to gradually decrease from the outside to the inside of the reflector, that is, the distance between the first steering electrode and the ground electrode and the distance between the second steering electrode and the ground electrode are set to change in a step-by-step manner. Since the smaller the distance between the first steering electrode, the second steering electrode and the ground electrode, the greater the capacitance, the greater the electrostatic adsorption force between the first steering electrode, the second steering electrode and the ground electrode, the electrostatic adsorption force can be increased by reducing the spacing between the steering electrode group and the ground electrode without reducing the maximum torsion angle of the reflector. In this way, under the condition of the same electrostatic adsorption force, the present disclosure can reduce the driving voltage and reduce the power consumption. In addition, when the ground electrode is deflected, due to the step-by-step change in distance, there are more gaps between the ground electrode and the first steering electrode or the second steering electrode, which is conducive to reducing the adhesion between the ground electrode and the first steering electrode or the second steering electrode, thereby reducing the probability of the attraction phenomenon.

[0088] Optionally, the reflector 3 may be made of metal material, or other materials capable of forming reflection.

[0089] In a specific implementation, in the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure, as Figure 2-Figure 4 As shown, the outer frame 1 and the rotating structure 2 can be an integral structure formed by a silicon substrate. Since the silicon substrate is a semiconductor, the reflector frame 21 of the rotating structure 2 can be directly reused as the ground electrode GND. Specifically, the galvanometer based on the MEMS process provided in the embodiment of the present disclosure can form an outer frame 1 for fixing the rotating structure 2 while forming the rotating structure 2, so that the outer frame 1 is used to fix the rotating structure 2 and other main structures of the MEMS galvanometer, which can increase the stability of the fixation and reduce the wear of the reflector 3 caused by the fixing process, thereby effectively improving the service life of the reflector 3.

[0090] Optionally, the silicon substrate may be made of single crystal silicon or polycrystalline silicon.

[0091] In specific implementation, the present disclosure can form the rotating structure 2 located in the hollow area of ​​the outer frame 1 by etching the silicon substrate, and the reflector 3 can be formed on the reflector frame 21 by deposition or sputtering. The above preparation processes are all relatively mature operation steps in the MEMS process, and the embodiments of the present disclosure will not be described in detail.

[0092] Specifically, Figure 2-Figure 5 As shown, the base 4 also adopts a silicon substrate, but it is certainly not limited to this.

[0093] In a specific implementation, in the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure, as Figure 2 , Figure 4 and Figure 5 As shown, the surface of the substrate 4 facing the reflector 3 is a flat surface, and the first steering electrode 51 and the second steering electrode 51 both include at least two step structures with thickness gradually increasing from the outside to the inside of the reflector 3, and each step structure serves as a sub-electrode. Compared with the completely flat steering electrode structure in the conventional structure, the embodiment of the present disclosure improves the steering electrode group into a step structure with thickness gradually increasing from both sides to the middle, which can ensure that while the spacing between the first steering electrode 51 and the ground electrode GND and between the second steering electrode 51 and the ground electrode GND is reduced, the maximum torsion angle of the reflector 3 will not be reduced, and the electrostatic adsorption force between the electrodes can be increased. In this way, under the condition of the same electrostatic adsorption force, the present disclosure can reduce the driving voltage and reduce power consumption.

[0094] Specifically, the calculation formula for the magnitude of the electric field formed between the first steering electrode 51 and the ground electrode GND and between the second steering electrode 51 and the ground electrode GND when voltage is applied is: The calculation formula of the electrostatic adsorption force between the first steering electrode 51 and the ground electrode GND and between the second steering electrode 51 and the ground electrode GND is: Among them, E is the electric field, C is the capacitance, V is the voltage, ε is the dielectric constant, d is the distance between the stepped structure and the ground electrode, F is the electrostatic adsorption force, and S is the facing area between the ground electrode and the steering electrode; according to the above-mentioned electrostatic adsorption force calculation formula, it can be known that when V is constant, the magnitude of the electrostatic adsorption force is inversely proportional to d, so the electrostatic strength can be enhanced by reducing d, and S is equivalent to the size of the projected overlapping area of ​​the ground electrode and the steering electrode, which has nothing to do with the surface undulation of the steering electrode. Therefore, the overall appearance of the steering electrode group is designed to be a stepped structure with a certain inclination angle. Under the premise of not affecting the maximum torsion angle of the reflector, the distance between the first steering electrode 51 and the ground electrode GND and the distance between the second steering electrode 51 and the ground electrode GND can be significantly reduced, thereby reducing the driving voltage and reducing power consumption.

[0095] It should be noted that, in the embodiment of the present disclosure, the first steering electrode 51 and the second steering electrode 51 each include three step structures as an example. Of course, they may each include two step structures, or four or more step structures. As long as the step structures gradually increase in thickness from both sides of the reflector 3 to the middle, they fall within the scope of protection of the embodiment of the present disclosure. The number of step structures in each steering electrode is designed according to actual needs.

[0096] In a specific implementation, in the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure, as Figure 6 and Figure 7 As shown, Figure 6 Schematic diagram of the deflection effect of driving the MEMS galvanometer when an AC voltage is applied to the first steering electrode 51. Figure 7 The schematic diagram of the deflection effect of driving the MEMS galvanometer when the second steering electrode 52 is loaded with an AC voltage, the first angle θ1 is formed between the inclined surface L1 formed by the first steering electrode 51 and the substrate 4, the first angle θ1 is formed between the inclined surface L2 formed by the second steering electrode 52 and the substrate 4, and the second angle θ2 is formed between the reflector frame 21 and the substrate 4 after the maximum angle is twisted, and the degree of the first angle θ1 is less than the degree of the second angle θ2. In this way, it can be ensured that while the spacing between the first steering electrode 51 and the ground electrode GND and between the second steering electrode 51 and the ground electrode GND is reduced, the maximum torsion angle of the reflector 3 will not be reduced, so the present disclosure will not limit the available angle range of the MEMS galvanometer, and thus will not limit the beam scanning range.

[0097] In a specific implementation, in the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure, as Figure 6 As shown, there is a gap between each two adjacent sub-electrodes (step structures) in the first steering electrode 51 and the second steering electrode 52, that is, the sub-electrodes in the first steering electrode 51 are spaced apart, and the sub-electrodes in the second steering electrode 52 are spaced apart. In this way, when the reflector frame 21 deflects toward the steering electrode side, since there is a gap between each two adjacent step structures, and ideally only the vertical edge of the step structure is in contact with the ground electrode GND, the setting of the gap is beneficial to reduce the adhesion between the steering electrode and the ground electrode, thereby reducing the probability of the attraction phenomenon.

[0098] Alternatively, if Figure 6 As shown, the gap width between the step structures of different heights may be 6 μm to 10 μm, for example, the gap width may be 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, etc.

[0099] In a specific implementation, in the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure, as Figure 2-Figure 4As shown, a pair of rotating shafts 22 are located on the same straight line and coincide with the central axis of the reflector 3, and the first steering electrode 51 and the second steering electrode 52 are symmetrically distributed on both sides of the central axis of the reflector 3. Specifically, the farther the sub-electrodes (stepped structure) in the steering electrode are from the central axis, the smaller the required driving voltage is, and vice versa. When the size of the ground electrode GND is fixed (that is, the size of the reflector frame 21 is fixed), when designing the step structure, it is necessary to ensure that the distance between the sub-electrodes and the central axis is not too large, resulting in a reduction in the electrode equivalent area.

[0100] In a specific implementation, in the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure, as Figure 2-Figure 4 As shown, the shape of the reflector 3 is the same as the shape of the reflector frame 21, and the size of the reflector 3 is the same as the size of the reflector frame 21. It should be noted that the size of the reflector 3 and the size of the reflector frame 21 are the same, which means that they are roughly the same. There may be certain errors in actual production. For example, the size of the reflector 3 may be slightly smaller than the size of the reflector frame 21.

[0101] In a specific implementation, in the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure, as Figure 2-Figure 4 As shown, the shape of the reflector 3 may be circular, and the rotating shaft 22 is connected to the outer annular surface of the reflector frame 21. Optionally, the shape of the reflector 3 may also be elliptical or the like.

[0102] In a specific implementation, in the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure, as Figure 4-Figure 9 As shown, Figure 8 for Figure 4 The middle part circuit connection structure diagram, Fig. 9 for Figure 4 The circuit connection structure diagram of the middle part, the MEMS galvanometer also includes: a plurality of contact electrodes 6 arranged between the steering electrode group 5 and the substrate 4 and arranged one-to-one with the step structure, a first driving structure 7 arranged between the contact electrode 6 and the substrate 4 and corresponding to the first steering electrode 51, and a second driving structure 7 arranged between the contact electrode 6 and the substrate 4 and corresponding to the second steering electrode 52; wherein,

[0103] The first steering electrode 51 is electrically connected to the corresponding contact electrode 6, and the second steering electrode 52 is electrically connected to the corresponding contact electrode 6;

[0104] Each contact electrode 6 corresponding to the first steering electrode 51 is electrically connected to the first driving structure 7, and each contact electrode 6 corresponding to the second steering electrode 52 is electrically connected to the second driving structure 8. Specifically, the bottom of the first steering electrode 51 is interconnected with the first driving structure 7 through the contact electrode 6, and the bottom of the second steering electrode 52 is interconnected with the second driving structure 8 through the contact electrode 6. Since the gap between adjacent step structures is very small, according to the edge effect of the electric field, the first steering electrode 51 and the second steering electrode 52 can be equivalent to a complete electrode without a gap. When working, the first driving structure 7 applies a driving voltage to the first steering electrode 51 through the contact electrode 6, and the second driving structure 8 applies a driving voltage to the second steering electrode 52 through the contact electrode 6, and an electric field is formed between them and the ground electrode GND to generate an electrostatic adsorption force, so that the reflector 3 is deflected in a preset direction, and the reflector 3 can reflect the laser beam emitted by the laser emitting component and project it into the corresponding scanning area.

[0105] In a specific implementation, in the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure, as Figure 4-Figure 9 As shown, the first driving structure 7 includes: a first driving electrode 71 electrically connected to each contact electrode 6 corresponding to the first steering electrode 51, and a first driving line 72 electrically connected to the first driving electrode 71;

[0106] The second driving structure 8 includes: a second driving electrode 81 electrically connected to each contact electrode 6 corresponding to the second steering electrode 52, and a second driving line 82 electrically connected to the second driving electrode 81. Specifically, in this embodiment, each contact electrode 6 corresponding to each step structure of different thicknesses in the first steering electrode 51 is arranged to be electrically connected to the same first driving electrode 71, and each contact electrode 6 corresponding to each step structure of different thicknesses in the second steering electrode 52 is arranged to be electrically connected to the same second driving electrode 72, that is, one driving structure connects all the step structures in the corresponding steering electrodes, so that the driving voltage is applied to all the step structures in the first steering electrode 51 through the first driving line 72, and the driving voltage is applied to all the step structures in the second steering electrode 52 through the second driving line 82, which can save the complexity of the driving structure design.

[0107] In a specific implementation, in order to avoid a short circuit between the contact electrode and the first drive structure, the second drive structure, and to avoid a short circuit between the contact electrode and the steering electrode group, in the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure, as Figure 4-Figure 8As shown, it also includes: a second isolation layer 9 arranged between the contact electrode 6 and the first drive structure 7, the second drive structure 8, and a third isolation layer 10 arranged between the contact electrode 6 and the steering electrode group 5; wherein the second isolation layer 9 exposes the first drive electrode 71 and the second drive electrode 81 to realize the electrical connection between the first drive electrode 71 and the second drive electrode 81 and the corresponding contact electrode 6 respectively; the third isolation layer 10 exposes the contact electrode 6 to realize the electrical connection between the contact electrode 6 and the first steering electrode 51 and the second steering electrode 52 respectively.

[0108] Optionally, the materials of the second isolation layer 9 and the third isolation layer 10 include but are not limited to insulating materials such as SiNx.

[0109] The following is a description of the embodiments of the present disclosure. Figure 2 The manufacturing process of the MEMS galvanometer shown in the figure is described, and the specific manufacturing process steps are as follows:

[0110] 1. Sputtering (Sputter) deposits a metal film layer (such as a Cu layer) on the substrate 4 (silicon substrate), and patterning and etching the metal film layer to form a first driving structure 7 and a second driving structure 8, such as Fig. 10A shown.

[0111] 2. Deposit a layer of SiNx film on the first driving structure 7 and the second driving structure 8 by PECVD, and pattern the SiNx film by ICP etching technology to expose the first driving electrode 71 and the second driving electrode 81, so as to form a second isolation layer 9. Fig. 10B shown.

[0112] 3. Sputter deposit a Cu layer on the second isolation layer 9 again, and pattern-etch the Cu layer to form a plurality of contact electrodes 6 corresponding to the first drive electrode 71 and the second drive electrode 81, as shown in FIG. Fig. 10C shown.

[0113] 4. A SiNx film layer is deposited again on the contact electrode 6 by PECVD, and the surface is flattened and the contact electrode 6 is exposed by chemical mechanical polishing (CMP) technology to form a third isolation layer 10. Fig. 10D shown.

[0114] 5. Sputter deposit a Cu layer on the third isolation layer 10, spin-coat a photoresist, and pattern-etch the Cu layer using a photoresist process to form a conductive structure corresponding to the contact electrode 6. Repeat the steps of depositing a Cu layer, spin-coating a photoresist, and patterning a Cu layer to form a stepped first steering electrode 51 and a second steering electrode 52 with a certain height difference, such as Fig. 10E shown.

[0115] 6. On another silicon substrate, an outer frame 1 and a rotating structure 2 are etched by ICP etching technology. The reflector frame 21 of the rotating structure 2 is reused as a ground electrode GND. The substrate 4 and the outer frame 1 are bonded together. Fig.10F shown.

[0116] 7. Spin-coat photoresist (sacrificial layer) Fig.10F The hollow area of ​​the reflector frame 21 is filled, and then a reflective material is coated on the surface of the reflector frame 21 to form a reflector 3. After removing the sacrificial layer, the reflector 3 provided in the embodiment of the present disclosure is obtained. Figure 2 The MEMS galvanometer shown.

[0117] In summary, the embodiments of the present disclosure provide Figure 2 The MEMS galvanometer shown has at least the following advantages:

[0118] 1. The MEMS galvanometer structure designed in the present disclosure is not complicated in design and can be manufactured using existing semiconductor device manufacturing technology. The overall manufacturing process is relatively simple.

[0119] 2. By replacing the conventional flat electrode structure with a stepped steering electrode, the distance between the steering electrode and the ground electrode can be reduced without reducing the maximum torsion angle of the galvanometer, thereby reducing the driving voltage and power consumption.

[0120] 3. When the reflector frame deflects toward the steering electrode, there is a gap between each two adjacent step structures, and ideally only the vertical edge of the step structure is in contact with the ground electrode. Therefore, the setting of the gap is beneficial to reduce the adhesion between the steering electrode and the ground electrode, thereby reducing the probability of the attraction phenomenon.

[0121] In a specific implementation, in the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure, as Figure 11-Figure 16 As shown, Fig.11 This is another structural diagram of a MEMS galvanometer. Fig.12 for Fig.11 The corresponding plan view is: Fig.13 for Fig.11 The corresponding exploded diagram of each layer structure, Fig.14 for Fig.12 Schematic diagram of the cross section of the partial structure along the AA' direction, Fig.15 Schematic diagram of the deflection effect of driving the MEMS galvanometer when an AC voltage is applied to the first steering electrode 51. Fig.16 Schematic diagram of the deflection effect of driving the MEMS galvanometer when the second steering electrode 52 is loaded with an AC voltage. The width of each step structure corresponding to the first steering electrode 51 gradually increases from the outside to the inside of the reflector 3, and the width of each step structure corresponding to the second steering electrode 52 gradually increases from the outside to the inside of the reflector 3. Fig.13 The MEMS galvanometer shown is Figure 4 Compared with the MEMS galvanometer shown in the figure, there is no obvious change in the overall structure. Only the width of the step structure with different thicknesses in the stepped steering electrode is changed. Figure 4 The equal width design of each step structure in the reflector 3 is changed to a design where the width gradually increases from the outside to the inside. Fig.13 and Figure 4 Structural changes can be compared Figure 14-16 and Figure 5-Figure 7 As can be seen from the schematic diagram, the maximum torsion angle of the MEMS galvanometer remains unchanged, the height difference, gap, overall width and position between the step structures of the stepped steering electrode remain unchanged, and only the step structures of different heights gradually widen from the outside to the inside of the reflector 3.

[0122] Specifically, Figure 11-Figure 14 As shown, when the reflector 3 is not twisted, the step structure with the smallest distance from the ground electrode GND is mainly driven. When the reflector 3 is twisted by a certain angle, the step structure with the largest distance from the ground electrode GND is mainly driven. Figure 11-Figure 14 Compared with the conventional MEMS galvanometer, the improvement of the step structure width gradient of the MEMS galvanometer in the embodiment can make the area of ​​the step structure larger during initial drive (when the reflector is not twisted), and can provide a greater electrostatic adsorption force under the same driving voltage. When the reflector 3 is twisted by the electrostatic adsorption force, although the area of ​​the step structure with the largest distance from the ground electrode is reduced, the twisted reflector 3 can compensate for the reduced electrostatic adsorption force through inertia.

[0123] Specifically, Figure 11-Figure 14 The other film structures and manufacturing processes in the Figure 2-Figure 5 The structure shown in the figure shows that the difference in manufacturing process is only that the width gradient is made when manufacturing the steering electrode group, which will not be elaborated here.

[0124] In specific implementation, Figure 4 and Fig.13 When the MEMS galvanometer is working, during the deflection of the ground electrode GND toward the steering electrode, when the torsion angle is the largest, the ground electrode GND and the steering electrode may be short-circuited, which may cause a transient strong current to break through the MEMS galvanometer and damage the MEMS galvanometer. Therefore, in the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure, Figure 17-Figure 20 As shown, Fig.17 This is another structural diagram of a MEMS galvanometer. Fig.18 for Fig.17 The corresponding plan view is: Fig.19 for Fig.17 The corresponding exploded diagram of each layer structure, Fig. 20 for Fig.18 The cross-sectional schematic diagram of the partial structure along the AA' direction in FIG. 1 shows that the MEMS galvanometer further includes a first isolation layer 11 disposed on the side of the steering electrode group 5 facing the ground electrode GND, and the orthographic projection of the first isolation layer 11 on the substrate 4 covers the substrate 4 and fills the gap. In this way, the first isolation layer 11 is added to cover the surface of the steering electrode group as an isolation layer during the process preparation process to protect the ground electrode GND from short circuit when it contacts the steering electrode.

[0125] Optionally, the material of the first isolation layer 11 includes but is not limited to insulating materials such as SiNx.

[0126] It should be noted that, during the deposition of SiNx, SiNx is filled in the gaps between the step structures of different depths. Since the gap width is less than 10 μm, it will not affect the edge effect of the steering electrode.

[0127] It should be noted that Figure 17-Figure 20 is Figure 2-Figure 5 On the basis of the first isolation layer 11, a first isolation layer 11 is provided on the side of the steering electrode group 5 facing the ground electrode GND; Figure 11-Figure 14 On the basis of the first isolation layer 11 is provided on the side of the steering electrode group 5 facing the ground electrode GND, such as Fig.21 As shown, Fig.21 for Fig.13 FIG. 1 is a schematic cross-sectional view of a partial structure along the AA′ direction after the first isolation layer 11 is provided.

[0128] Specifically, Figure 17-Figure 21 The other film structures in the Figure 2-Figure 5 The description of the structure shown is not repeated here.

[0129] Specifically, Fig.17 The manufacturing process of the MEMS galvanometer shown is similar to that described above. Figure 2 The manufacturing process of the MEMS galvanometer shown in the figure is different in that: after the step-type first steering electrode 51 and the second steering electrode 52 are completed in step 5, a material such as SiNx can be deposited as a first isolation layer 11 by a PECVD process to cover the first steering electrode 51 and the second steering electrode 52. Fig.22A Afterwards, the same Figure 2 Steps 6 and 7 in the manufacturing process shown in FIG. 1 , and the corresponding structure after step 6 is as follows Fig. 22B As shown, the corresponding structure after step 7 is as follows Fig.17 As shown. Figure 10A-10E , Fig.22A , Fig. 22B and Fig.17 For production Fig.17 The process flow chart of the MEMS galvanometer is shown.

[0130] In a specific implementation, when the MEMS galvanometer provided in the embodiment of the present disclosure is applied to a laser radar, in order to increase the scanning area of ​​the laser radar, in the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure, as Figure 23-Figure 27 As shown, Fig.23 This is another structural diagram of a MEMS galvanometer. Fig.24 for Fig.23 The corresponding plan view is: Fig.25 for Fig.23 The corresponding exploded diagram of each layer structure, Fig.26 for Fig.25 The middle part circuit connection structure diagram, Fig. 27 for Fig.25 In the circuit connection structure diagram of the middle part, the shape of the reflector 3 can be square, a pair of side edges of the reflector frame 21 have a concave structure, and the rotating shaft 22 is embedded in the concave structure and connected to the reflector frame 21. Fig.17 On the basis of the above, the reflector 3 of the MEMS galvanometer is changed from the original circle to a square, that is, the reflector frame 21 is changed from the original circle to a square, so that the chamber space of the outer frame 1 can be used to the maximum extent, thereby increasing the scanning range of the galvanometer. At the same time, due to the increase in the reflector frame 21, it means that the effective area corresponding to the ground electrode GND and the steering electrode is increased, so the steering electrode is correspondingly lengthened to both sides, thereby increasing its effective area. According to the above-mentioned calculation formula of electrostatic adsorption force, a greater electrostatic adsorption force is obtained under the same driving voltage.

[0131] Specifically, Figure 23-Figure 27 The other film structures in the Figure 2-Figure 5 The structure shown in the figure is different only in that the shape of the reflector 3 and the reflector frame 21 is changed to a square, and the length of the steering electrode is increased accordingly, which will not be elaborated here.

[0132] Specifically, Fig.23 The manufacturing process of the MEMS galvanometer shown in the figure can refer to the aforementioned manufacturing process. Figure 2 The process flow shown in the figure differs in that a first isolation layer is deposited to cover the steering electrode group after the steering electrode group is manufactured, and when the outer frame 1 and the rotating structure 2 are manufactured, the reflector frame 21 is made into a square shape and a pair of side edges of the reflector frame 21 have a concave structure, and the rotating shaft 22 is embedded in the concave structure and connected to the reflector frame 21. Fig.23 The manufacturing process flow chart of the MEMS galvanometer is shown in Figure 28A-28G , Fig.23 shown.

[0133] It should be noted that Figure 25-27 The first driving line 72, the second driving line 82 and the aforementioned Figure 4 , Figure 8 and Fig. 9 The connection positions of the first driving line 72 and the second driving line 82 in the steering electrode and the step structure are different, but the functions are the same.

[0134] In a specific implementation, in the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure, as Figure 29-Figure 32 As shown, Fig.29 This is an exploded schematic diagram of the structure of each layer of the MEMS galvanometer. Fig.30 for Fig.29 The middle part circuit connection structure diagram, Fig.31 for Fig.29 The middle part circuit connection structure diagram, Fig.32 for Fig.29 The schematic cross-sectional view of the structure of the middle part shows that the first driving structure 7 includes: first driving electrodes 71 electrically connected to the contact electrodes 6 corresponding to the first steering electrodes 51 in a one-to-one correspondence, and first driving lines 72 electrically connected to the first driving electrodes 71 in a one-to-one correspondence;

[0135] The second driving structure 8 includes: second driving electrodes 81 electrically connected to each contact electrode 6 corresponding to the second steering electrode 52, and second driving lines 82 electrically connected to each second driving electrode 81. In this embodiment, the first driving electrodes 71 under the stepped structures of different thicknesses are changed from the original one-to-many (one first driving electrode 71 is connected to all corresponding stepped structures through the contact electrode 6) to one-to-one (one first driving electrode 71 is connected to a corresponding stepped structure through the contact electrode 6), and each first driving electrode 71 is electrically connected to a different first driving line 72, and the second driving electrodes 81 under the stepped structures of different thicknesses are changed from the original one-to-many (one first driving electrode 71 is connected to all corresponding stepped structures through the contact electrode 6) to one-to-one (one second driving electrode 81 is connected to a corresponding stepped structure through the contact electrode 6), and each second driving electrode 81 is electrically connected to a different second driving line 82. The driving structure routing distribution is as follows: Fig.30 and Fig.31 As shown, taking each steering electrode including three step structures as an example, each steering electrode is divided into three steps of different thicknesses and connected to the driving electrode below through the contact electrode 6 respectively. Other structural designs can still adopt the aforementioned Figure 2-28G The solution of any embodiment in the embodiment, the specific structure is as follows Fig.29 The present disclosure provides Fig.29 The MEMS galvanometer shown uses a multi-channel driving structure to connect step structures of different thicknesses one-to-one, and different power-on modes for the steering electrodes can be realized by powering with a digital control signal.

[0136] Specifically, compared to Figure 8 and Fig. 9 The single-channel control steering electrode shown, Fig.30 and Fig.31 Through the digital signal multi-channel control steering electrode, not only can the power be simultaneously Figure 8 and Fig. 9 The same effect can also be achieved by determining the on and off of different step structures according to the torsion angle of the reflector. For example, when the reflector is not twisted, the thickest step structure with a smaller distance from the ground electrode is mainly driven. When the reflector is twisted by a certain angle, the thinnest step structure with a larger distance from the ground electrode is mainly driven, achieving various forms of free control. In addition, separately controlling the step-type steering electrodes can also reduce power consumption.

[0137] Specifically, Figure 29-Figure 32 The other film structures in the Figure 2-Figure 5 The description of the structure shown in the figure only differs in that the connection mode between the first driving structure 7, the second driving structure 8 and the contact electrode 6 is changed, and a detailed description thereof will not be given here.

[0138] It should be noted that the above Figure 2-Figure 32 The MEMS galvanometers shown are all provided with stepped steering electrodes to reduce the distance between the ground electrode and the steering electrode, and other improvements are made on the basis of the stepped steering electrodes. Of course, in specific implementations, in order to reduce the distance between the ground electrode and the steering electrode, other designs may also be used, for example, Fig.33 As shown, Fig.33 This is a schematic diagram of the structure of another MEMS galvanometer provided in an embodiment of the present disclosure. The substrate 4 has at least two step structures with thickness gradually increasing from the outside to the inside of the reflector 3 at the positions corresponding to the first steering electrode 51 and the second steering electrode 52. The first steering electrode 51 and the second steering electrode 52 are arranged on the corresponding step structures. Specifically, the first steering electrode 51 and the second steering electrode 52 each include a sub-electrode arranged corresponding to the step structure, and the thickness of each sub-electrode is the same, so that the above-mentioned Figure 2-Figure 32 The same effect can be achieved by designing a single-drive driving structure to realize multi-way control of the steering electrode, thereby reducing power consumption. According to the calculation formula of the electrostatic adsorption force: It can be seen that the magnitude of the electrostatic adsorption force is independent of the thickness of the steering electrode. Therefore, in this embodiment, a stepped substrate 4 is designed to replace the steering electrodes of different thicknesses in the previous embodiment, and then a layer of Cu metal is deposited on the substrate 4 and patterned to form a steering electrode. Similarly, a steering electrode with a different spacing from the ground electrode GND can be formed.

[0139] In specific implementation, Fig.33The first steering electrode 51 can be an integral structure, and the second steering electrode 52 can be an integral structure, so that the steering electrodes can be controlled in a single path, and the complexity of the driving structure design can be reduced.

[0140] In the specific implementation, the production Fig.33 The MEMS galvanometer shown can firstly form a base 4 with a stepped gradient height on a silicon substrate by multiple etchings, and then deposit a layer of Cu metal to pattern a driving structure and a steering electrode with a certain gap. The process steps of the outer frame 1 and the rotating structure 2 are the same as those in the above-mentioned embodiment. Finally, they are bonded together to form a MEMS galvanometer, and a reflector is formed on the reflector frame.

[0141] Specifically, Fig.33 The other membrane structures in the corresponding MEMS galvanometer refer to the above Figure 2-Figure 32 The main difference in the structure shown is that the structures of the substrate 1 and the steering electrode are different, which will not be described here.

[0142] In a specific implementation, in order to reduce the distance between the ground electrode and the steering electrode, other designs may be used, for example, Fig.34 As shown, Fig.34 This is a schematic diagram of the structure of another MEMS galvanometer provided in an embodiment of the present disclosure. The ground electrode GND faces the surface of the substrate 1 and the corresponding positions of the first steering electrode 51 and the second steering electrode 52 have at least two step structures with thickness gradually increasing from the outside to the inside of the reflector 3. In this embodiment, the steering electrode adopts a traditional flat structure, and the ground electrode GND is designed to be a step-type structure with a gradually decreasing distance from the outside to the inside with the steering electrode, which can also achieve the same as the aforementioned Figure 2-Figure 32 In terms of specific process steps, a conventional flat steering electrode structure is prepared on a substrate, and multiple ICP etching techniques are used to form a Fig.34 The required stepped ground electrode GND is finally made into a complete MEMS galvanometer through process steps such as bonding, preparing the reflector, and releasing the sacrificial layer.

[0143] In the structure of the traditional flat mirror frame, the larger the size of the MEMS oscillator, the larger the moment of inertia of the mirror, and the lower the resonant frequency. Fig.34 The MEMS galvanometer structure design shown can move the mass distribution of the reflector frame from both sides to the direction of the rotation axis, reducing the rotational inertia required for twisting the two sides of the reflector frame, that is, increasing the resonant frequency of the MEMS galvanometer.

[0144] In a specific implementation, in the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure, as Fig.34As shown, the first steering electrode 51 can be an integral structure, and the second steering electrode 52 can be an integral structure. Of course, the first steering electrode 51 and the second steering electrode 52 can also include sub-electrodes arranged corresponding to each step structure in the ground electrode GND, and the thickness of each sub-electrode is the same. In this way, single-channel control of the steering electrode and multi-channel control of the steering electrode can be achieved, and control can be performed according to actual needs.

[0145] Specifically, Fig.34 The other membrane structures in the corresponding MEMS galvanometer refer to the above Figure 2-Figure 34 The description of the structure shown mainly differs in the structures of the ground electrode GND and the steering electrode, which will not be elaborated here.

[0146] In a specific implementation, in the above-mentioned MEMS galvanometer provided in the embodiment of the present disclosure, as Fig.33 and Fig.34 As shown, there is a gap between each two adjacent sub-electrodes in the first steering electrode 51 and the second steering electrode 52. The setting of the gap is conducive to reducing the adhesion between the steering electrode and the ground electrode, thereby reducing the probability of the attraction phenomenon. Optionally, the gap width can be 6μm to 10μm, for example, the gap width can be 6μm, 7μm, 8μm, 9μm, 10μm, etc.

[0147] In addition, the MEMS galvanometer provided in the embodiments of the present disclosure also has the following advantages:

[0148] 1. The MEMS galvanometer provided in the embodiment of the present disclosure is an actively tunable one-dimensional MEMS galvanometer, which drives the rotation of the MEMS galvanometer through the electrostatic adsorption force generated between the ground electrode GND and the first steering electrode 51 or the second steering electrode 52. It has the characteristics of simple structure, small size and mature process of traditional electrostatically driven MEMS galvanometer.

[0149] 2. The MEMS galvanometer provided in the embodiments of the present disclosure is only a simple improvement on the conventional MEMS galvanometer, and the implementation process is simple and the cost fluctuation is small.

[0150] Based on the same inventive concept, the embodiment of the present disclosure also provides a MEMS galvanometer array, such as Fig.35 As shown, it includes a plurality of MEMS galvanometers arranged in an array as provided in any of the embodiments of the present disclosure. Specifically, Fig.35 The MEMS galvanometer array shown has the beneficial effects of the aforementioned MEMS galvanometer, and when the MEMS galvanometer provided in the embodiment of the present disclosure is applied to a laser radar, the MEMS galvanometer array reflects external laser beams, thereby enabling the laser radar to obtain a larger scanning range.

[0151] like Fig.36As shown, Fig.36 The schematic diagram of the transmitting and receiving system corresponding to the MEMS galvanometer array provided in the embodiment of the present disclosure when applied to a laser radar. In a laser radar system composed of traditional optical reflectors, a larger torsion angle of the reflector is required to achieve a wider range of scanning. However, the present disclosure adopts a multiple group of MEMS galvanometer arrays, and the maximum torsion angle of each MEMS galvanometer unit 100 does not change, but the MEMS galvanometer array can also achieve a wider range of scanning. Moreover, the volume of the MEMS galvanometer realized by micromachining technology changes less and has a high degree of integration.

[0152] like Fig.35 As shown, in the embodiment of the present disclosure, the stepped MEMS galvanometer units 100 are periodically arranged to obtain a MEMS galvanometer array. The example given in this embodiment is a 4×4 array arrangement. In actual application, it is not limited to this arrangement form, and different arrangement designs can be made according to actual needs.

[0153] In a specific implementation, in the above-mentioned MEMS galvanometer array provided in the embodiment of the present disclosure, as Fig.35 As shown, when the MEMS galvanometer adopts Figure 8 In the circuit structure shown, the first steering electrode 51 in each MEMS galvanometer corresponds to a first driving line 72, and the second steering electrode 52 in each MEMS galvanometer corresponds to a second driving line 82. Each first driving line 72 in each MEMS galvanometer is electrically connected to the same first driving voltage terminal (-), and each second driving line 82 in each MEMS galvanometer is electrically connected to the same second driving voltage terminal (+). Specifically, the first driving voltage terminal (-) is a negative AC voltage, and the second driving voltage terminal (+) is a positive AC voltage. The AC voltage is loaded on the first driving voltage terminal (-) or the second driving voltage terminal (+) according to the preset deflection direction of the reflector 3. Fig.35As shown, the MEMS galvanometer array further includes a plurality of first wirings 20 and a plurality of second wirings 30 extending in the row direction and alternately arranged in the column direction, and a first wiring 20 and a second wiring 30 are correspondingly arranged on both sides of each row of galvanometer units 100 in the row direction; the MEMS galvanometer array further includes a third wiring 40 and a fourth wiring 50 arranged at the periphery of the plurality of galvanometer units 100; the embodiment of the present disclosure electrically connects the first driving lines 72 corresponding to each row of the plurality of galvanometer units 100 arranged in the array to the corresponding first wirings 20, and then connects all the first wirings 20 to the third wirings 40 and the fourth wirings 50; The three wirings 40 are electrically connected, and the third wiring 40 is electrically connected to the first driving voltage terminal (-); all the second driving lines 82 corresponding to the multiple galvanometer units 100 arranged in the array are electrically connected to the corresponding second wirings 30, and then all the second wirings 30 are electrically connected to the fourth wiring 50, and the fourth wiring 50 is electrically connected to the second driving voltage terminal (+), so that all the first steering electrodes 51 in the present disclosure are driven simultaneously by the same first driving voltage terminal (-), and all the second steering electrodes 52 are driven simultaneously by the same second driving voltage terminal (+), so that a larger scanning range can be obtained.

[0154] In a specific implementation, in the above-mentioned MEMS galvanometer array provided in the embodiment of the present disclosure, as Fig.35 As shown, when the MEMS galvanometer is used Fig.30 In the circuit structure shown, the first steering electrode 51 in each MEMS galvanometer corresponds to a plurality of first drive lines 72 having the same number as the step structure, and the second steering electrode 52 in each MEMS galvanometer corresponds to a plurality of second drive lines 82 having the same number as the step structure, and each first drive line 72 in each MEMS galvanometer is electrically connected to the same first drive voltage terminal (-), and each second drive line 82 in each MEMS galvanometer is electrically connected to the same second drive voltage terminal (+). In this way, all first steering electrodes 51 can be driven simultaneously by the same first drive voltage terminal (-), and all second steering electrodes 52 can be driven simultaneously by the same second drive voltage terminal (+), so that a larger scanning range can be obtained.

[0155] Fig.35 The manufacturing process of the MEMS galvanometer array shown in FIG. Figure 37A-Figure 37D As shown, the basic process flow and Figure 2 The manufacturing process of the MEMS galvanometer shown is the same, specifically:

[0156] 1. A first driving structure 7 and a second driving structure 8 are formed on a substrate 1, and a first wiring 20, a second wiring 30, a third wiring 40, a fourth wiring 50, a first driving voltage terminal (-) and a second driving voltage terminal (+) are formed. Fig.37A shown.

[0157] 2. In Fig.37ABased on the Figure 2 The second isolation layer 9, the contact electrode 6, and the third isolation layer 10 in the manufacturing process of the MEMS galvanometer shown in the figure, the third isolation layer 10 exposes the contact electrode 6, the first driving voltage terminal (-) and the second driving voltage terminal (+), as shown in FIG. Fig.37B shown.

[0158] 3. In Fig.37B Made on the basis of Figure 2 The first steering electrode 51 and the second steering electrode 52 in the manufacturing process of the MEMS galvanometer are shown in FIG. Fig.37C shown.

[0159] Afterwards, make Figure 2 The outer frame 1 and the rotating structure 2 in the manufacturing process of the MEMS galvanometer shown in the figure are bonded together with the substrate 4 and the outer frame 1, the sacrificial layer is filled in the hollow area, the reflector 3 is formed, and the sacrificial layer is removed to obtain Fig.35 The MEMS galvanometer array shown in FIG. Fig.37D shown.

[0160] In specific implementation, in the above-mentioned MEMS galvanometer array provided in the embodiment of the present disclosure, when the MEMS galvanometer adopts Fig.30 In the circuit structure shown, the first steering electrode 51 in each MEMS galvanometer corresponds to a plurality of first driving lines 72 having the same number as the step structure, and the second steering electrode 52 in each MEMS galvanometer corresponds to a plurality of second driving lines 82 having the same number as the step structure; wherein,

[0161] Each first driving line corresponding to the step structure located at the same position in each MEMS galvanometer is electrically connected to the same first driving voltage terminal. For example, each first driving line 72 corresponding to each step structure with the smallest thickness in each MEMS galvanometer is electrically connected to the same first driving voltage terminal (-), each first driving line 72 corresponding to each step structure with the middle thickness in each MEMS galvanometer is electrically connected to the same first driving voltage terminal (-), and each first driving line 72 corresponding to each step structure with the largest thickness in each MEMS galvanometer is electrically connected to the same first driving voltage terminal (-); each first driving line corresponding to the step structure located at different positions in each MEMS galvanometer is electrically connected to different first driving voltage terminals, for example, each first driving line 72 corresponding to each step structure with different thickness in each MEMS galvanometer is electrically connected to different first driving voltage terminals (-);

[0162] Each second drive line corresponding to the step structure located at the same position in each MEMS galvanometer is electrically connected to the same second drive voltage terminal. For example, each second drive line 82 corresponding to each step structure with the smallest thickness in each MEMS galvanometer is electrically connected to the same second drive voltage terminal (+), each second drive line 82 corresponding to each step structure with the middle thickness in each MEMS galvanometer is electrically connected to the same second drive voltage terminal (+), and each second drive line 82 corresponding to each step structure with the largest thickness in each MEMS galvanometer is electrically connected to the same second drive voltage terminal (+); each second drive line corresponding to the step structure located at different positions in each MEMS galvanometer is electrically connected to a different second drive voltage terminal. For example, each second drive line 82 corresponding to each step structure with different thickness in each MEMS galvanometer is electrically connected to a different second drive voltage terminal (+). That is, the MEMS galvanometer array provided in the embodiment of the present disclosure can use digital signal multi-channel control steering electrodes on the basis of achieving a larger scanning range, which can not only be powered on at the same time to achieve the same Fig.35 The same effect can also be achieved by determining the on and off of different step structures according to the torsion angle of the reflector. For example, when the reflector is not twisted, the thickest step structure with a smaller distance from the ground electrode is mainly driven. When the reflector is twisted by a certain angle, the thinnest step structure with a larger distance from the ground electrode is mainly driven, achieving various forms of free control. In addition, separately controlling the step-type steering electrodes can also reduce power consumption.

[0163] Based on the same inventive concept, an embodiment of the present disclosure further provides a radar system, including the above-mentioned MEMS galvanometer of the embodiment of the present disclosure, or including the above-mentioned MEMS galvanometer array of the embodiment of the present disclosure.

[0164] Optionally, the radar system may be a laser radar, such as Fig.36 As shown, the laser radar includes a laser emitting component, a beam receiving component and an optical scanning component. The laser emitting component is used to emit a laser beam; the beam receiving component is used to receive an echo beam. The optical scanning component is a MEMS galvanometer in any of the above embodiments, which is used to reflect the laser beam and then irradiate it to the scanning environment, and reflect the echo beam reflected from the scanning environment to the beam receiving component.

[0165] The embodiment of the present disclosure provides a MEMS galvanometer, a MEMS galvanometer array and a radar system. When the ground electrode and the substrate are parallel, the distance between the first steering electrode and the ground electrode is set to gradually decrease from the outside to the inside of the reflector, and the distance between the second steering electrode and the ground electrode is set to gradually decrease from the outside to the inside of the reflector, that is, the distance between the first steering electrode and the ground electrode and the distance between the second steering electrode and the ground electrode are set to change in a step-by-step manner. Since the smaller the distance between the first steering electrode, the second steering electrode and the ground electrode, the greater the capacitance, the greater the electrostatic adsorption force between the first steering electrode, the second steering electrode and the ground electrode, the electrostatic adsorption force can be increased by reducing the spacing between the steering electrode group and the ground electrode without reducing the maximum torsion angle of the reflector. In this way, under the condition of the same electrostatic adsorption force, the present disclosure can reduce the driving voltage and reduce the power consumption. In addition, when the ground electrode is deflected, due to the step-by-step change in distance, there are more gaps between the ground electrode and the first steering electrode or the second steering electrode, which is conducive to reducing the adhesion between the ground electrode and the first steering electrode or the second steering electrode, thereby reducing the probability of the attraction phenomenon.

[0166] Although the preferred embodiments of the present disclosure have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present disclosure.

[0167] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present disclosure without departing from the spirit and scope of the embodiments of the present disclosure. Thus, if these modifications and variations of the embodiments of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is also intended to include these modifications and variations.

Claims

1. A MEMS galvanometer, wherein: include: An outer frame, wherein the outer frame is a hollow structure; A rotating structure, the rotating structure is located in the hollow area of ​​the outer frame, the rotating structure includes a reflector frame and a pair of rotating shafts connected between the reflector frame and the outer frame, and the reflector frame includes a ground electrode; A reflector, located on the reflector frame; A base, wherein the base and the outer frame form a cavity; A steering electrode group is located on the side of the substrate facing the rotating structure, and the steering electrode group includes a first steering electrode and a second steering electrode arranged on both sides of the pair of rotating shafts; wherein, When the ground electrode and the substrate are parallel, the distance between the first steering electrode and the ground electrode gradually decreases from the outside to the inside of the reflector, and the distance between the second steering electrode and the ground electrode gradually decreases from the outside to the inside of the reflector.

2. The MEMS galvanometer according to claim 1, wherein: The surface of the substrate facing the reflector is a flat surface. The first steering electrode and the second steering electrode each include at least two step structures with thickness gradually increasing from the outside to the inside of the reflector. Each of the step structures serves as a sub-electrode.

3. The MEMS galvanometer according to claim 1, wherein: The substrate has at least two step structures at positions corresponding to the first steering electrode and the second steering electrode, the thickness of which gradually increases from the outer side to the inner side of the reflector, and the first steering electrode and the second steering electrode are arranged on the corresponding step structures.

4. The MEMS galvanometer according to claim 2 or 3, wherein: A first angle is formed between the inclined surface formed by each steering electrode and the substrate, and a second angle is formed between the reflector frame and the substrate after being twisted at the maximum angle. The first angle is smaller than the second angle.

5. The MEMS galvanometer according to claim 1, wherein: The ground electrode faces the surface of the substrate and has at least two step structures whose thickness gradually increases from the outside to the inside of the reflector at positions corresponding to the first steering electrode and the second steering electrode.

6. The MEMS galvanometer according to claim 3 or 5, wherein: The first steering electrode and the second steering electrode each include sub-electrodes arranged corresponding to the stepped structure, and each of the sub-electrodes has the same thickness.

7. The MEMS galvanometer according to claim 2 or 6, wherein: There is a gap between each two adjacent sub-electrodes in the first steering electrode and the second steering electrode.

8. The MEMS galvanometer according to claim 7, wherein: It also includes a first isolation layer arranged on the side of the steering electrode group facing the ground electrode, and the orthographic projection of the first isolation layer on the substrate covers the substrate and fills the gap.

9. The MEMS galvanometer according to any one of claims 2 to 8, wherein: The width of each of the step structures corresponding to the first steering electrode gradually increases from the outer side to the inner side of the reflector, and the width of each of the step structures corresponding to the second steering electrode gradually increases from the outer side to the inner side of the reflector.

10. The MEMS galvanometer according to any one of claims 1 to 9, wherein: The outer frame and the rotating structure are an integrated structure formed by using a silicon substrate, and the reflector frame is reused as the ground electrode.

11. The MEMS galvanometer according to any one of claims 1 to 10, wherein: The pair of rotation axes are located on the same straight line and coincide with the central axis of the reflector, and the first steering electrode and the second steering electrode are symmetrically distributed on both sides of the central axis of the reflector.

12. The MEMS galvanometer according to any one of claims 1 to 11, wherein: The shape of the reflector is the same as that of the reflector frame, and the size of the reflector is the same as that of the reflector frame.

13. The MEMS galvanometer according to claim 12, wherein: The shape of the reflector includes a circle or an ellipse, and the rotating shaft is connected to the outer annular surface of the reflector frame.

14. The MEMS galvanometer according to claim 12, wherein: The reflector is in a square shape, a pair of side edges of the reflector frame have a concave structure, and the rotating shaft is embedded in the concave structure and connected to the reflector frame.

15. The MEMS galvanometer according to any one of claims 2 to 9, wherein: Also includes: A plurality of contact electrodes are arranged between the steering electrode group and the substrate and are arranged one-to-one with the step structure, a first driving structure is arranged between the contact electrode and the substrate and corresponds to the first steering electrode, and a second driving structure is arranged between the contact electrode and the substrate and corresponds to the second steering electrode; wherein, The first steering electrode is electrically connected to the corresponding contact electrode, and the second steering electrode is electrically connected to the corresponding contact electrode; The contact electrodes corresponding to the first steering electrodes are electrically connected to the first driving structure, and the contact electrodes corresponding to the second steering electrodes are electrically connected to the second driving structure.

16. The MEMS galvanometer according to claim 15, wherein: The first driving structure comprises: a first driving electrode electrically connected to each of the contact electrodes corresponding to the first steering electrode, and a first driving line electrically connected to the first driving electrode; The second driving structure includes: a second driving electrode electrically connected to each of the contact electrodes corresponding to the second steering electrode, and a second driving line electrically connected to the second driving electrode.

17. The MEMS galvanometer according to claim 15, wherein: The first driving structure comprises: first driving electrodes electrically connected to the contact electrodes corresponding to the first steering electrodes in a one-to-one correspondence, and first driving lines electrically connected to the first driving electrodes in a one-to-one correspondence; The second driving structure includes: second driving electrodes electrically connected to the contact electrodes corresponding to the second steering electrodes in a one-to-one correspondence, and second driving lines electrically connected to the second driving electrodes in a one-to-one correspondence.

18. The MEMS galvanometer according to claim 17, wherein: Also includes: A second isolation layer is arranged between the contact electrode and the first drive structure, the second drive structure, and a third isolation layer is arranged between the contact electrode and the steering electrode group; wherein the second isolation layer exposes the first drive electrode and the second drive electrode, and the third isolation layer exposes the contact electrode.

19. A MEMS galvanometer array, wherein: It comprises a plurality of MEMS galvanometers as described in any one of claims 1 to 18 arranged in an array.

20. The MEMS galvanometer array according to claim 19, wherein: The first steering electrode in each of the MEMS galvanometers corresponds to one or multiple first driving lines which are equal to the number of the step structures, and the second steering electrode in each of the MEMS galvanometers corresponds to one or multiple second driving lines which are equal to the number of the step structures. Each of the first driving lines in each of the MEMS galvanometers is electrically connected to the same first driving voltage terminal, and each of the second driving lines in each of the MEMS galvanometers is electrically connected to the same second driving voltage terminal.

21. The MEMS galvanometer array according to claim 19, wherein: The first steering electrode in each of the MEMS galvanometers corresponds to a plurality of first driving lines having the same number as the step structure, and the second steering electrode in each of the MEMS galvanometers corresponds to a plurality of second driving lines having the same number as the step structure; wherein, The first driving lines corresponding to the step structures at the same position in the MEMS galvanometers are electrically connected to the same first driving voltage terminal, and the first driving lines corresponding to the step structures at different positions in the MEMS galvanometers are electrically connected to different first driving voltage terminals; The second driving lines corresponding to the stepped structures at the same position in the MEMS galvanometers are electrically connected to the same second driving voltage terminal, and the second driving lines corresponding to the stepped structures at different positions in the MEMS galvanometers are electrically connected to different second driving voltage terminals.

22. A radar system, wherein: It comprises the MEMS galvanometer as claimed in any one of claims 1 to 18, or comprises the MEMS galvanometer array as claimed in any one of claims 19 to 21.

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