Galvanometer unit, preparation method thereof, scanning mirror and radar system

Abstract

The invention discloses a galvanometer unit and a preparation method thereof, a scanning mirror and a radar system, the galvanometer unit comprises a first substrate and a second substrate which are arranged in a bonding manner, the second substrate comprises a galvanometer structure accommodated in a cavity structure, the galvanometer structure is provided with a rotating shaft, and the first substrate comprises an electrostatic driving structure; the plate electrode faces the second substrate and is insulated from the electrostatic driving structure, and the electrostatic driving structure drives the plate electrode to reciprocate in the first direction; the plate electrode comprises a first main electrode and a second main electrode which are positioned on different sides of the rotating shaft; in the process that the electrostatic driving structure drives the plate electrode to reciprocate, the overlapping area between the first main electrode and the galvanometer structure and the overlapping area between the second main electrode and the galvanometer structure are changed, so that the electrostatic attraction force acting on the galvanometer structure is changed, and the galvanometer structure is driven to rotate along the rotating shaft.

Description

Technical Field

[0001] The present disclosure relates to the field of micro-electromechanical technology, and in particular to a galvanometer unit and a preparation method thereof, a scanning mirror, and a radar system. Background Art

[0002] A micro-electro-mechanical system (MEMS) galvanometer is a tiny, drivable mirror made based on MEMS technology, and the mirror diameter is usually only a few millimeters.

[0003] Compared with traditional optical scanning mirrors, it has the advantages of light weight, small size, easy mass production and low production cost. It performs 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 augmented reality (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.

[0004] There are four driving modes for MEMS galvanometers: electrostatic, electromagnetic, piezoelectric and electrothermal. Among them, electrostatic driving is divided into two driving structures: flat electrode and comb electrode (vertical comb teeth). The MEMS galvanometer unit driven by flat electrodes is simple and has low processing difficulty, but a large driving voltage is required to produce adsorption through the electrostatic attraction between the flat electrodes, and attraction is prone to occur. A group of vertical comb teeth relative to the comb electrode are respectively applied with positive voltage and grounded, and an electrostatic force is generated between the relative vertical comb teeth. This force drives the vertical comb teeth to move, and then drives the micromirror connected to the vertical comb teeth to move. However, the vertical comb teeth have the problem of difficult alignment process in the manufacturing process, resulting in high production costs. Summary of the invention

[0005] The embodiments of the present disclosure provide a galvanometer unit and a method for manufacturing the same, a scanning mirror, and a radar system to solve the above-mentioned technical problems.

[0006] In a first aspect, in order to solve the above technical problems, an embodiment of the present disclosure provides a galvanometer unit, comprising a first substrate and a second substrate bonded together, wherein the first substrate has a groove, the second substrate has a cavity structure, the second substrate comprises a galvanometer structure accommodated in the cavity structure, the galvanometer structure has a rotation axis, the rotation axis is fixed to the cavity structure, and the first substrate comprises:

[0007] a first substrate base plate;

[0008] An electrostatic driving structure, located on one side of the first substrate;

[0009] a flat plate electrode, located on a side of the electrostatic drive structure away from the first substrate, and insulated from the electrostatic drive structure, wherein the electrostatic drive structure drives the flat plate electrode to reciprocate in a first direction; the flat plate electrode comprises a first main electrode and a second main electrode located on different sides of the rotation axis; wherein the first direction is perpendicular to an extension direction of the rotation axis;

[0010] During the reciprocating motion, the overlapping areas of the first main electrode, the second main electrode and the galvanometer structure change, so that the electrostatic attraction acting on the galvanometer structure changes, driving the galvanometer structure to rotate along the rotation axis.

[0011] In a possible implementation manner, after being grounded, the galvanometer structure respectively forms two flat plate capacitors with the first main electrode and the second main electrode.

[0012] In a possible implementation manner, the electrostatic drive structure includes:

[0013] a stationary comb-tooth electrode and a movable comb-tooth electrode meshing with each other, wherein the movable comb-tooth electrode is used to reciprocate relative to the stationary comb-tooth electrode in a plane parallel to the first substrate substrate along the first direction under the action of electrostatic attraction between the movable comb-tooth electrode and the stationary comb-tooth electrode, wherein the first direction is the extension direction of the comb teeth;

[0014] The stationary comb-tooth electrode is fixed to one side surface of the first substrate, the moving comb-tooth electrode is fixed to the groove by an elastic member, the moving comb-tooth electrode and a side of the stationary comb-tooth electrode away from the first substrate are located in the same plane, and a side of the stationary comb-tooth electrode close to the first substrate is in contact with the first substrate, a side of the moving comb-tooth electrode close to the first substrate is suspended, and the flat electrode is fixed to the surface of the moving comb-tooth electrode away from the first substrate.

[0015] In a possible implementation manner, the movable comb-tooth electrode includes: a first comb-tooth substrate and a second comb-tooth substrate arranged opposite to each other, a plurality of movable comb teeth, a connecting portion connecting the first comb-tooth substrate and the second comb-tooth substrate, and a plurality of first cantilever beams;

[0016] The first comb tooth substrate and the second comb tooth substrate are arranged along the first direction and extend along the second direction, and the connecting portion or the first comb tooth substrate and the second comb tooth substrate are respectively fixed to the groove through the multiple first cantilever beams; the multiple movable comb teeth extend along the first direction and are arranged along the second direction, and the multiple movable comb teeth are spaced and fixed on the first comb tooth substrate and the second comb tooth substrate; the first direction is perpendicular to the second direction.

[0017] In a possible implementation manner, the stationary comb-tooth electrode comprises: a third comb-tooth substrate and a fourth comb-tooth substrate that are arranged opposite to each other, and a plurality of stationary comb teeth, wherein the third comb-tooth substrate is insulated from the fourth comb-tooth substrate;

[0018] The third comb tooth substrate and the fourth comb tooth substrate are arranged along the first direction and extend along the second direction; the multiple static comb teeth extend along the first direction and are arranged along the second direction, the multiple static comb teeth are arranged at intervals and fixed on the third comb tooth substrate and the fourth comb tooth substrate, and the static comb teeth fixed on the third comb tooth substrate are meshed with the dynamic comb teeth fixed on the first comb tooth substrate, and the static comb teeth fixed on the fourth comb tooth substrate are staggered with the dynamic comb teeth fixed on the second comb tooth substrate.

[0019] In a possible implementation manner, there is one connecting portion, and the connecting portion is connected to the middle position of the first comb tooth substrate and the second comb tooth substrate;

[0020] The third comb tooth substrate and the fourth comb tooth substrate are located between the first comb tooth substrate and the second comb tooth substrate, and the third comb tooth substrate and the fourth comb tooth substrate are both divided into two parts by the connecting part, and the two parts are connected to each other through the connecting line;

[0021] Alternatively, the third comb-tooth substrate and the fourth comb-tooth substrate are located on both sides of the first comb-tooth substrate and the second comb-tooth substrate.

[0022] In a possible implementation manner, there are two connecting parts, and the two connecting parts are respectively connected to the ends of the first comb tooth substrate and the second comb tooth substrate, and the first comb tooth substrate, the second comb tooth substrate and the two connecting parts are sequentially connected to form a closed pattern;

[0023] The orthographic projections of the plurality of stationary comb teeth and the plurality of dynamic comb teeth on the first base substrate are both located inside the closed pattern; or, the orthographic projections of the plurality of stationary comb teeth and the plurality of dynamic comb teeth on the first base substrate are both located outside the closed pattern.

[0024] In a possible implementation manner, when the orthographic projections of the plurality of stationary comb teeth and the plurality of dynamic comb teeth on the first substrate are both located inside the closed pattern, the stationary comb tooth electrode further includes:

[0025] The insulating structure is located between the third comb-tooth substrate and the fourth comb-tooth substrate.

[0026] In a possible implementation manner, the first comb-tooth substrate and the second comb-tooth substrate have a hollow structure.

[0027] In a possible implementation manner, the first substrate further includes:

[0028] A first isolation layer is located between the movable comb-tooth electrode and the flat plate electrode, wherein the orthographic projection of the first isolation layer on the first base substrate covers the first comb-tooth substrate, the second comb-tooth substrate and the plurality of first cantilever beams.

[0029] In a possible implementation manner, the flat plate electrode further includes: a plurality of second cantilever beams;

[0030] The orthographic projection of the first main electrode on the first base substrate covers the first comb-tooth substrate, the orthographic projection of the second main electrode on the first base substrate covers the second comb-tooth substrate, and the first main electrode and the second main electrode are respectively fixed to the groove through the plurality of second cantilever beams.

[0031] In a possible implementation manner, the first main electrode and the second main electrode further cover a portion of the movable comb teeth connected to the first comb tooth substrate and the second comb tooth substrate, respectively.

[0032] In a possible implementation manner, the flat electrode further includes: a first auxiliary electrode and a second auxiliary electrode; the orthographic projection of the first auxiliary electrode on the first base substrate covers the third comb tooth substrate and a portion of the stationary comb teeth connected to the third comb tooth substrate, and the orthographic projection of the second auxiliary electrode on the first base substrate covers the fourth comb tooth substrate and a portion of the stationary comb teeth connected to the fourth comb tooth substrate; in the process of the movable comb tooth electrode driving the flat electrode to reciprocate, the first auxiliary electrode contacts the first main electrode, or the second auxiliary electrode contacts the first main electrode.

[0033] In a possible implementation manner, the first isolation layer also covers the first auxiliary electrode and the second auxiliary electrode, and a surface of the first isolation layer facing the first substrate has a plurality of recessed structures, and the recessed structures cover a plurality of corresponding comb teeth.

[0034] In a possible implementation manner, a side surface of the first substrate has a concave structure overlapping with the groove, and the stationary comb-tooth electrode is located in the concave structure.

[0035] In a possible implementation manner, the galvanometer structure further includes:

[0036] a second substrate, the second substrate having an opening, wherein the opening coincides with the cavity structure;

[0037] A rotating plate, fixedly connected to the rotating shaft, and configured to rotate along the rotating shaft under the action of the electrostatic attraction of the two flat plate capacitors;

[0038] The reflector is located on a side surface of the rotating plate away from the first substrate and is fixed to the rotating plate.

[0039] In a second aspect, an embodiment of the present disclosure provides a scanning mirror, comprising one or a plurality of galvanometer units as described in the first aspect arranged in an array.

[0040] In a third aspect, an embodiment of the present disclosure provides a method for preparing a galvanometer unit, comprising:

[0041] An electrostatic driving structure is formed on one side of the first substrate;

[0042] A flat plate electrode is formed on a side of the electrostatic driving structure away from the first substrate to obtain a first substrate; the flat plate electrode includes a first main electrode and a second main electrode arranged along a first direction, and the electrostatic driving structure drives the flat plate electrode to reciprocate in the first direction and is insulated from the electrostatic driving structure;

[0043] An opening is formed in the second base substrate, and a rotating plate is formed in a region corresponding to the opening, so as to obtain a second substrate having a cavity structure; wherein the cavity structure coincides with the opening, the rotating plate is located in the cavity structure, the rotating plate has a rotating shaft, and the rotating shaft is fixed to the cavity structure;

[0044] After the second substrate is aligned with the first substrate, a reflective layer is deposited on the surface of the rotating plate away from the first substrate, and the reflective layer is patterned to obtain a reflector; wherein, after being grounded, the rotating plate forms two flat plate capacitors with the first main electrode and the second main electrode; the first main electrode and the second main electrode are located on different sides of the rotating axis; in the process of the electrostatic driving structure driving the flat plate electrodes to reciprocate, the overlapping areas of the first main electrode and the second main electrode with the rotating plate change, so that the electrostatic attraction forces of the two flat plate capacitors acting on the rotating plate respectively change, thereby driving the rotating plate to rotate along the rotating axis.

[0045] In a possible implementation, an electrostatic driving structure is formed on one side of the first substrate, including:

[0046] Etching the first substrate to obtain a first substrate having a recessed structure;

[0047] Depositing a first metal layer on the bottom surface of the recessed structure, and etching the first metal layer to obtain a stationary comb-tooth electrode;

[0048] Depositing a first silicon nitride layer on a side of the stationary comb-tooth electrode away from the first substrate, and patterning the first silicon nitride layer to obtain a first sub-isolation layer covering the connection line of the stationary comb-tooth electrode;

[0049] Depositing a second silicon nitride layer on a side of the first substrate close to the first sub-isolation layer, and patterning the second silicon nitride layer to obtain a second sub-isolation layer covering an area outside the recessed structure; wherein the second isolation layer includes the first sub-isolation layer and the second sub-isolation layer;

[0050] A second metal layer is deposited on a side of the second sub-isolation layer away from the base substrate, and the second metal layer is etched to obtain the movable comb-tooth electrode fixedly connected to the second sub-isolation layer and meshing with the stationary comb-tooth electrode; wherein the movable comb-tooth electrode is used to reciprocate along the first direction relative to the stationary comb-tooth electrode in a plane parallel to the first base substrate under the action of electrostatic attraction, and the first direction is the extension direction of the comb teeth.

[0051] In a possible implementation manner, a flat plate electrode is formed on a side of the electrostatic drive structure away from the first substrate, including:

[0052] A third silicon nitride layer is deposited on a side of the movable comb-tooth electrode away from the first substrate, and the third silicon nitride layer is patterned to obtain a first isolation layer covering the first comb-tooth substrate and the second comb-tooth substrate and a plurality of first cantilever beams; wherein the movable comb-tooth electrode comprises: a first comb-tooth substrate and a second comb-tooth substrate arranged opposite to each other, a plurality of movable comb teeth, a connecting portion connecting the first comb-tooth substrate and the second comb-tooth substrate, and a plurality of first cantilever beams; the plurality of movable comb teeth are arranged along the first direction and extend along the second direction, and the plurality of movable comb teeth are arranged at intervals and fixed on the first comb-tooth substrate and the second comb-tooth substrate; the first direction is perpendicular to the second direction;

[0053] A third metal layer is deposited on a side of the first isolation layer away from the base substrate, and the third metal layer is patterned to obtain the flat electrode; wherein the first main electrode covers the first comb-tooth substrate, and the second main electrode covers the second comb-tooth substrate.

[0054] In a fourth aspect, an embodiment of the present disclosure provides a radar system, including:

[0055] A laser emitting component, used for emitting laser;

[0056] Reflection unit;

[0057] As the scanning mirror of the second aspect, the reflection unit reflects the laser to the scanning mirror, and the obstacle is scanned by the scanning mirror;

[0058] A focusing lens, used for focusing the laser reflected by the obstacle;

[0059] A beam receiving component, used for receiving the laser focused by the focusing lens;

[0060] The control component is used to form an image of the obstacle according to the signal fed back by the beam receiving component. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 A top view of a galvanometer unit provided in an embodiment of the present disclosure;

[0062] Figure 2 The embodiments of the present disclosure provide Figure 1 A front view at position AA' along the direction of extension of the rotation axis;

[0063] Figure 3 A top view of a galvanometer structure twisted toward a second main electrode provided in an embodiment of the present disclosure;

[0064] Figure 4 The embodiments of the present disclosure provide Figure 3 A front view at position AA' along the direction of extension of the rotation axis;

[0065] Figure 5 A top view of a galvanometer structure twisted toward a first main electrode provided in an embodiment of the present disclosure;

[0066] Figure 6 The embodiments of the present disclosure provide Figure 5 A front view at position AA' along the direction of extension of the rotation axis;

[0067] Figure 7 A schematic top view of another galvanometer unit provided in an embodiment of the present disclosure;

[0068] Figure 8 The embodiments of the present disclosure provide Figure 7 The front view along the AA' direction;

[0069] Fig. 9 A three-dimensional schematic diagram of a galvanometer unit provided in an embodiment of the present disclosure;

[0070] Fig.10An exploded diagram of a galvanometer unit provided in an embodiment of the present disclosure;

[0071] Fig.11 A top view of an electrostatic drive structure provided in an embodiment of the present disclosure;

[0072] Fig.12 A schematic diagram of another electrostatic drive structure provided in an embodiment of the present disclosure;

[0073] Fig.13 and Fig.14 A schematic diagram of another electrostatic drive structure provided in an embodiment of the present disclosure;

[0074] Figure 15 to Figure 17 A schematic diagram of another electrostatic drive structure provided in an embodiment of the present disclosure;

[0075] Fig.18 A top view of a first isolation layer provided in an embodiment of the present disclosure;

[0076] Fig.19 and Fig. 20 A bottom view of a first isolation layer provided in an embodiment of the present disclosure;

[0077] Fig.21 and Fig. 22 A top view of a flat plate electrode provided in an embodiment of the present disclosure;

[0078] Fig.23 A top view of another flat plate electrode provided in an embodiment of the present disclosure;

[0079] Fig.24 and Fig.25 A bottom view of a flat plate electrode provided in an embodiment of the present disclosure;

[0080] Fig.26 A top view of another flat plate electrode provided in an embodiment of the present disclosure;

[0081] Fig. 27 A top view of another galvanometer structure twisted toward the second main electrode provided by an embodiment of the present disclosure;

[0082] Fig.28 The embodiments of the present disclosure provide Fig. 27 A front view at position AA' along the direction of extension of the rotation axis;

[0083] Fig.29 A top view of another galvanometer structure twisted toward the first main electrode provided by an embodiment of the present disclosure;

[0084] Fig.30 The embodiments of the present disclosure provide Fig. 27 A front view at position AA' along the direction of extension of the rotation axis;

[0085] Fig.31 A top view of a first isolation layer provided in an embodiment of the present disclosure;

[0086] Fig.32 A bottom view of a first isolation layer provided in an embodiment of the present disclosure;

[0087] Fig.33 A top view of a first substrate provided in an embodiment of the present disclosure;

[0088] Fig.34 The embodiments of the present disclosure provide Fig.32 Cross-sectional view along the BB' direction;

[0089] Fig.35 A three-dimensional schematic diagram of a first substrate provided in an embodiment of the present disclosure;

[0090] Fig.36 A flow chart of a method for preparing a galvanometer unit provided in an embodiment of the present disclosure;

[0091] Fig.37 A schematic diagram of manufacturing a galvanometer unit is provided for an embodiment of the present disclosure;

[0092] Fig.38 A schematic diagram of manufacturing an electrostatic drive structure is provided for an embodiment of the present disclosure;

[0093] Fig.39 A schematic diagram of manufacturing a flat electrode is provided for an embodiment of the present disclosure;

[0094] Fig.40 A schematic diagram of the structure of a laser system provided in an embodiment of the present disclosure.

[0095] Reference numerals:

[0096] The first substrate 1, the groove M, the first base substrate 11, the electrostatic driving structure 12, the static comb-tooth electrode 121, the dynamic comb-tooth electrode 122, the flat electrode 13, the first main electrode 131, the second main electrode 132, the second cantilever beam 133, the first auxiliary electrode 134, the second auxiliary electrode 135, the first comb-tooth substrate 1221, the second comb-tooth substrate 1222, the dynamic comb teeth 1223, the connecting portion 1224, the first cantilever beam 1225, the third comb-tooth substrate 1211, the fourth comb-tooth substrate 1212, the static comb teeth 1213, the insulating structure 1214, the connecting line 1215, the recessed structure M', the first isolation layer 14, the second isolation layer 15, the first sub-isolation layer 151, the second sub-isolation layer 152, the third sub-isolation layer 141, the fourth sub-isolation layer 142, the first direction X, the second direction Y;

[0097] The second substrate 2 , the second base substrate 20 , the cavity structure N, the galvanometer structure 21 , the rotating plate 211 , the reflecting mirror 212 , and the rotating shaft 22 . DETAILED DESCRIPTION

[0098] The embodiments of the present disclosure provide a galvanometer unit and a method for manufacturing the same, a scanning mirror, and a radar system to solve the above-mentioned technical problems.

[0099] In order to make the above-mentioned purposes, features and advantages of the present disclosure more obvious and easy to understand, the present disclosure will be further described below with reference to the accompanying drawings and examples. However, the example embodiments can be implemented in various forms and should not be understood as being limited to the embodiments described herein; on the contrary, these embodiments are provided to make the present disclosure more comprehensive and complete, and to fully convey the concepts of the example embodiments to those skilled in the art. The same figure marks in the figures represent the same or similar structures, and thus their repeated descriptions will be omitted. The words expressing position and direction described in the present disclosure are all explained using the accompanying drawings as examples, but changes can be made as needed, and the changes made are all included in the scope of protection of the present disclosure. The drawings of the present disclosure are only used to illustrate the relative position relationship and do not represent the true proportion.

[0100] It should be noted that specific details are described in the following description to facilitate a full understanding of the present disclosure. However, the present disclosure can be implemented in a variety of other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present disclosure. Therefore, the present disclosure is not limited to the specific implementation methods disclosed below. The subsequent description of the specification is a preferred implementation method for implementing the present disclosure, but the description is for the purpose of illustrating the general principles of the present disclosure and is not intended to limit the scope of the present disclosure. The scope of protection of the present disclosure shall be determined by the definition of the attached claims.

[0101] In conjunction with the accompanying drawings, a galvanometer unit and a preparation method thereof, a scanning mirror, and a radar system provided in an embodiment of the present disclosure are described in detail below.

[0102] See also Figure 1 and Figure 2 , Figure 1 A top view of a galvanometer unit provided in an embodiment of the present disclosure, Figure 2 The embodiments of the present disclosure provide Figure 1 The front view at the AA' position along the extending direction of the rotation axis, the galvanometer unit, includes a first substrate 1 and a second substrate 2 bonded together, the first substrate 1 has a groove M, the second substrate 2 has a cavity structure N, the groove M and the cavity structure N cooperate to form a chamber, the second substrate 2 includes a galvanometer structure 21 accommodated in the cavity structure N, the galvanometer structure 21 has a rotation axis 22, the rotation axis 22 is fixed to the cavity structure N, the first substrate 1 includes:

[0103] A first substrate 11;

[0104] The electrostatic driving structure 12 is located on one side of the first substrate 11;

[0105] The flat plate electrode 13 is located on a side of the electrostatic driving structure 12 away from the first substrate 11 and is insulated from the electrostatic driving structure 12. The electrostatic driving structure 12 drives the flat plate electrode 13 to reciprocate in the first direction X. The flat plate electrode 13 includes a first main electrode 131 and a second main electrode 132 located on different sides of the rotating shaft 22. The first direction X is perpendicular to the extension direction of the rotating shaft 22. The electrostatic driving structure 12 and the flat plate electrode 13 are both accommodated in the groove M and fixedly installed with the groove M by an elastic member. After being grounded, the galvanometer structure 21 forms two flat plate capacitors with the first main electrode 131 and the second main electrode 132.

[0106] When the electrostatic driving structure 12 drives the flat electrode 13 to reciprocate, the overlapping area between the first main electrode 131 and the second main electrode 132 and the galvanometer structure 21 changes, causing the electrostatic attraction acting on the galvanometer structure 21 to change, thereby driving the galvanometer structure 21 to rotate along the rotation axis 22.

[0107] The first main electrode 131 and the second main electrode 132 are connected to positive and negative voltages respectively, and the galvanometer structure 21 is connected to the ground voltage. At this time, the overlapping areas of the first main electrode 131 , the second main electrode 132 and the galvanometer structure 21 form two flat plate capacitors.

[0108] The calculation formula for the plate capacitor is:

[0109] C = εS / d (1);

[0110] Wherein, C is the capacitance value of the flat plate capacitor, ε is the dielectric constant of the flat plate capacitor, S is the facing area of ​​the flat plate capacitor (ie, the area of ​​the overlapping area), and d is the distance between the flat plate electrode 13 and the galvanometer structure 21 .

[0111] The calculation formula of the electrostatic attraction force generated by the flat capacitor acting on the galvanometer structure 21 is:

[0112] F=(εSV 2 ) / (2d 2 ) (2);

[0113] Wherein, F is the electrostatic attraction force exerted by the flat capacitor on the galvanometer structure 21 , and V is the voltage difference between the first main electrode 131 and the second main electrode 132 .

[0114] As can be seen from formula (2), the magnitude of the parallel-plate capacitance and the electrostatic attraction force it generates are determined by S, d, and V of the parallel-plate capacitance. Therefore, not only can the electrostatic attraction force acting on both sides of the galvanometer structure 21 about the rotation axis 22 be changed by varying the voltage difference between the first main electrode 131 and the second main electrode 132, but also the electrostatic attraction force on both sides of the galvanometer structure 21 located about the rotation axis 22 can be changed simultaneously by varying the facing area of the parallel-plate capacitances corresponding to the first main electrode 131 and the second main electrode 132, thereby effectively increasing the electrostatic attraction force acting on both sides of the galvanometer structure 21 about the rotation axis 22, making the change in the electrostatic attraction force received by both sides of the galvanometer structure 21 about the rotation axis 22 more significant, and further promoting the resonant motion of the galvanometer structure 21 to achieve the effect of causing the galvanometer structure 21 to twist.

[0115] The overlapping area between the first main electrode 131 and the galvanometer structure 21 is denoted as S1, and the overlapping area between the second main electrode 132 and the galvanometer structure 21 is denoted as S2.

[0116] In Figure 1 and Figure 2 , S1 = S2. At this time, the electrostatic attraction forces received by the two parts of the galvanometer structure 21 on both sides of the rotation axis 22 are the same, and the galvanometer structure 21 remains balanced and does not rotate.

[0117] Please refer to Figure 3 to Figure 6 , Figure 3 which is a top view of a galvanometer structure twisting towards the second main electrode provided by an embodiment of the present disclosure, Figure 4 is provided by an embodiment of the present disclosure Figure 3 and is a front view along the extension direction of the rotation axis at the AA' position in Figure 5 which is a top view of a galvanometer structure twisting towards the first main electrode provided by an embodiment of the present disclosure, Figure 6 is provided by an embodiment of the present disclosure Figure 5 and is a front view along the extension direction of the rotation axis at the AA' position in

[0118] In Figure 3 and Figure 4 , the electrostatic drive structure 12 drives the galvanometer structure 21 to move in the opposite direction of the first direction X, causing the overlapping areas between the first main electrode 131, the second main electrode 132 and the galvanometer structure 21 to change. At this time, S1 < S2. According to formula (2), it can be known that the electrostatic attraction force received by the side of the galvanometer structure 21 corresponding to S1 decreases, and the electrostatic attraction force received by the side of the galvanometer structure 21 corresponding to S2 increases, causing the galvanometer structure 21 to rotate towards the side corresponding to S2.

[0119] In Figure 5 and Figure 6The electrostatic driving structure 12 drives the galvanometer structure 21 to move along the first direction X, so that the overlapping area between the first main electrode 131, the second main electrode 132 and the galvanometer structure 21 changes. At this time, S1>S2. According to formula (2), at this time, the electrostatic attraction force on the side of the galvanometer structure 21 corresponding to S1 increases, and the electrostatic attraction force on the side of the galvanometer structure 21 corresponding to S2 decreases, and the galvanometer structure 21 rotates toward the side corresponding to S1.

[0120] When the electrostatic driving structure 12 drives the first main electrode 131 and the second main electrode 132 to reciprocate in the first direction X, the overlapping area of ​​the first main electrode 131 and the second main electrode 132 with the galvanometer structure 21 also alternates between increasing and decreasing, thereby causing the electrostatic attraction acting on the galvanometer structure 21 on both sides of the rotating axis 22 to alternate between increasing and decreasing, causing the galvanometer structure 21 to twist back and forth along the rotating axis 22.

[0121] In the embodiment provided by the present disclosure, a first main electrode 131 and a second main electrode 132 arranged along a first direction X are arranged on a side of the electrostatic driving structure 12 away from the first substrate 11, and the electrostatic driving structure 12 drives the first main electrode 131 and the second main electrode 132 to reciprocate in the first direction X; the galvanometer structure 21 is grounded to form two flat plate capacitors with the first main electrode 131 and the second main electrode 132, so that in the process of the electrostatic driving structure 12 driving the first main electrode 131 and the second main electrode 132 to reciprocate, the overlapping area of ​​the first main electrode 131 and the second main electrode 132 with the galvanometer structure 21 changes, so as not to The electrostatic attraction acting on the galvanometer structure 21 on both sides of the rotating shaft 22 can be changed only by changing the voltage difference between the first main electrode 131 and the second main electrode 132. The electrostatic attraction of the galvanometer structure 21 on both sides of the rotating shaft 22 can also be changed by simultaneously changing the overlapping area of ​​the first main electrode 131, the second main electrode 132 and the galvanometer structure 21. This effectively improves the electrostatic attraction acting on the galvanometer structure 21 on both sides of the rotating shaft 22, and makes the change of the electrostatic attraction received by the galvanometer structure 21 on both sides of the rotating shaft 22 more significant, thereby promoting the resonant motion of the galvanometer structure 21, thereby achieving a more significant effect of twisting the galvanometer structure 21.

[0122] In addition, during the reciprocating movement of the first main electrode 131 and the second main electrode 132 along the first direction X, since the first main electrode 131 and the second main electrode 132 can be displaced relative to the galvanometer structure 21, when the first main electrode 131 or the second main electrode 132 contacts and produces adhesion with the galvanometer structure 21, the movement of the first main electrode 131 and the second main electrode 132 in the first direction X causes the first main electrode 131 or the second main electrode 132 to be misaligned with the galvanometer structure 21, thereby releasing the adhesion, reducing the failure probability of the galvanometer unit, and thereby improving the reliability of the galvanometer unit.

[0123] Please continue to see Figure 2 , the second substrate 2 further includes:

[0124] A second substrate 20, wherein the second substrate 20 has an opening, and the opening coincides with the cavity structure N;

[0125] The rotating plate 211 is fixedly connected to the rotating shaft 22, and the rotating plate 211 is used to rotate along the rotating shaft 22 under the action of the electrostatic attraction of the two flat plate capacitors;

[0126] The reflector 212 is located on a side surface of the rotating plate 211 away from the first substrate 1 and is fixed to the rotating plate 211. The reflector 212 is used to reflect light, such as laser light.

[0127] The rotating plate 211 is grounded via the rotating shaft 22 . Under the action of the electrostatic adsorption force, the rotating plate 211 can not only rotate along the rotating shaft 22 , but also support the reflector 212 fixed thereto and drive the reflector 212 to rotate synchronously.

[0128] In some embodiments, the material used for the rotating plate 211 may be a metal material or a semiconductor material.

[0129] See also Figure 7 to Figure 9 , Figure 7 A schematic top view of another galvanometer unit provided in an embodiment of the present disclosure, Figure 8 The embodiments of the present disclosure provide Figure 7 The front view along the AA' direction, Fig. 9 A three-dimensional schematic diagram of a galvanometer unit provided in an embodiment of the present disclosure.

[0130] The electrostatic driving structure 12 comprises a stationary comb-tooth electrode 121 and a movable comb-tooth electrode 122 meshing with each other, wherein the movable comb-tooth electrode 122 is used to reciprocate relative to the stationary comb-tooth electrode 121 in a plane parallel to the first substrate 11 along a first direction X under the action of the electrostatic attraction between the stationary comb-tooth electrode 121 and the stationary comb-tooth electrode 121, wherein the first direction X is the extension direction of the comb teeth;

[0131] The stationary comb-tooth electrode 121 is fixed to one side surface of the first base substrate 11, the moving comb-tooth electrode 122 is fixed to the groove M by an elastic member, the moving comb-tooth electrode 122 and the side of the stationary comb-tooth electrode 121 away from the first base substrate 11 are located in the same plane, and the side of the stationary comb-tooth electrode 121 close to the first base substrate 11 is in contact with the first base substrate 11, and the side of the moving comb-tooth electrode 122 close to the first base substrate 11 is suspended, and the flat plate electrode 13 is fixed to the surface of the moving comb-tooth electrode 122 away from the first base substrate 11, and is insulated from the moving comb-tooth electrode 122, such as a second isolation layer 15 is set between the moving comb-tooth electrode 122 and the stationary comb-tooth electrode 121.

[0132] like Fig. 9 As shown, the groove M is composed of a second isolation layer 15 located between the stationary comb-tooth electrode 121 and the moving comb-tooth electrode 122, a first isolation layer 14 located between the moving comb-tooth electrode 122 and the flat electrode 13, and a first base substrate 11. The second isolation layer 15 includes a first sub-isolation layer 151 and a second sub-isolation layer 152. The first sub-isolation layer 151 surrounds the electrostatic drive structure 12 and is located between the static comb-tooth electrode 121 and the dynamic comb-tooth electrode 122, and covers a portion of the signal line led out from the static comb-tooth electrode 121. The second sub-isolation layer surrounds the electrostatic drive structure 12 and is arranged on the same layer as the dynamic comb-tooth electrode 122, and has the same thickness. The first isolation layer 14 includes a third sub-isolation layer 141 and a fourth sub-isolation layer 142. The third sub-isolation layer 141 is located between the dynamic comb-tooth electrode 142 and the flat electrode 13, has a frame surrounding the electrostatic drive structure 12, and completely covers a portion of the dynamic comb-tooth electrode 122, so that the dynamic comb-tooth electrode 122 is insulated from the flat electrode 13. The fourth sub-isolation layer 142 surrounds the electrostatic drive structure 12 and is arranged on the same layer as the flat electrode 13, and has the same thickness. The first sub-isolating layer 151, the second sub-isolating layer 152, the frame of the third sub-isolating layer 141, and the fourth sub-isolating layer 142 overlap in the orthographic projection on the first base substrate 11, and the orthographic projection pattern is the shape of the portion of the groove M protruding from the plane where the first base substrate 11 is located. They together constitute the side wall of the groove M, and the first base substrate 11 constitutes the bottom of the groove M. Fig.10 , which is an exploded view of a galvanometer unit provided in an embodiment of the present disclosure.

[0133] In the embodiment provided by the present disclosure, the electrostatic driving structure 12 includes a stationary comb-tooth electrode 121 and a moving comb-tooth electrode 122 that mesh with each other, and the moving comb-tooth electrode 122 is used to reciprocate along a first direction X relative to the stationary comb-tooth electrode 121 in a plane parallel to the first substrate 11 under the action of the electrostatic attraction force with the stationary comb-tooth electrode 121, and the first direction X is the extension direction of the comb teeth, the stationary comb-tooth electrode 121 is fixed to a side surface of the first substrate 11, the moving comb-tooth electrode 122 and the groove M are fixedly installed by an elastic member, the moving comb-tooth electrode 122 and the side of the stationary comb-tooth electrode 121 away from the first substrate 11 are located in the same plane, and the side of the stationary comb-tooth electrode 121 close to the first substrate 11 is in contact with the first substrate 11, and the moving comb-tooth electrode 122 is located in the same plane as the stationary comb-tooth electrode 121. The tooth electrode 122 is suspended on one side close to the first base substrate 11, and the flat electrode 13 is fixed to the surface of the moving comb-tooth electrode 122 on the side away from the first base substrate 11, so that the comb teeth of the static comb-tooth electrode 121 and the moving comb-tooth electrode 122 are parallel comb teeth that are easy to prepare, and the moving comb-tooth electrode 122 is combined with the flat electrode 13, so that the moving comb teeth 1223, the flat electrode 13, the galvanometer structure 21 and the reflector 212 have sufficient movement space, thereby reducing the difficulty of the manufacturing process, and the movement of the moving comb-tooth electrode 122 in the electrostatic drive structure 12 in the first direction X can drive the flat electrode 13 to reciprocate in the first direction X, so that the overlapping area of ​​the first main electrode 131 and the second main electrode 132 with the galvanometer structure 21 changes.

[0134] See also Fig.11 A top view of an electrostatic drive structure provided in an embodiment of the present disclosure.

[0135] The movable comb-tooth electrode 122 includes: a first comb-tooth substrate 1221 and a second comb-tooth substrate 1222 arranged opposite to each other, a plurality of movable comb teeth 1223, a connecting portion 1224 connecting the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222, and a plurality of first cantilever beams 1225;

[0136] The first comb tooth substrate 1221 and the second comb tooth substrate 1222 are arranged along the first direction X and extend along the second direction Y. The connecting portion 1224 or the first comb tooth substrate 1221 and the second comb tooth substrate 1222 are respectively fixed to the groove M through a plurality of first cantilever beams 1225 (i.e., elastic members); the plurality of movable comb teeth 1223 extend along the first direction X and are arranged along the second direction Y. The plurality of movable comb teeth 1223 are arranged at intervals and fixed on the first comb tooth substrate 1221 and the second comb tooth substrate 1222; the first direction X is perpendicular to the second direction Y; Fig.11Since the stationary comb-tooth electrode 121 and the movable comb-tooth electrode 122 need to be arranged between the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222, the distance between the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 is relatively large. At this time, the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 are fixed to the groove M by a plurality of first cantilever beams 1225, so as to ensure that the movable comb-tooth electrode 122 has sufficient displacement space;

[0137] The static comb-tooth electrode 121 includes: a third comb-tooth substrate 1211 and a fourth comb-tooth substrate 1212 arranged opposite to each other, and a plurality of static comb teeth 1213. The third comb-tooth substrate 1211 and the fourth comb-tooth substrate 1212 are insulated from each other. Fig.11 In the embodiment, the third comb-tooth substrate 1211 and the fourth comb-tooth substrate 1212 are insulated by providing an insulating structure 1214;

[0138] The third comb tooth substrate 1211 and the fourth comb tooth substrate 1212 are arranged along the first direction X and extend along the second direction Y; a plurality of static comb teeth 1213 extend along the first direction X and are arranged along the second direction Y, and a plurality of static comb teeth 1213 are arranged at intervals and fixed on the third comb tooth substrate 1211 and the fourth comb tooth substrate 1212, and the static comb teeth 1213 fixed on the third comb tooth substrate 1211 are meshed with the dynamic comb teeth 1223 fixed on the first comb tooth substrate 1221, and the static comb teeth 1213 fixed on the fourth comb tooth substrate 1212 are alternately arranged with the dynamic comb teeth 1223 fixed on the second comb tooth substrate 1222.

[0139] In the embodiment provided by the present disclosure, the movable comb-tooth electrode 122 is configured to be composed of a first comb-tooth substrate 1221 and a second comb-tooth substrate 1222 arranged oppositely, a plurality of movable comb teeth 1223, a connecting portion 1224 connecting the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222, and a plurality of first cantilever beams 1225, and the stationary comb-tooth electrode 121 is configured to be composed of a third comb-tooth substrate 1211 and a fourth comb-tooth substrate 1212 arranged oppositely, and a plurality of stationary comb teeth 1213, so as to and an insulating structure 1214 located between the third comb tooth substrate 1211 and the fourth comb tooth substrate 1212, and the stationary comb teeth 1213 fixed on the third comb tooth substrate 1211 are arranged alternately with the dynamic comb teeth 1223 fixed on the first comb tooth substrate 1221, and the stationary comb teeth 1213 fixed on the fourth comb tooth substrate 1212 are arranged alternately with the dynamic comb teeth 1223 fixed on the second comb tooth substrate 1222, so that the third comb tooth substrate 1211 and the fourth comb tooth substrate 1212 are arranged alternately. After positive and negative voltages are loaded respectively, charges of opposite electrical properties will be carried on the staggered positive comb teeth and negative comb teeth, thereby generating an uneven electric field. Under the action of electrostatic attraction, the movable comb teeth 1223 fixed on the first comb tooth substrate 1221 or the second comb tooth substrate 1222 will move toward the third comb tooth substrate 1211 or the fourth comb tooth substrate 1212. Since the first comb tooth substrate 1221 and the second comb tooth substrate 1222 are fixedly connected by the connecting portion 1224, the first comb tooth substrate 1221 and the second comb tooth substrate 1222 are respectively fixed to the groove M by a plurality of first cantilever beams 1225. Therefore, when the first comb tooth substrate 1221 or the second comb tooth substrate 1222 moves toward the corresponding third comb tooth substrate 1211 or the fourth comb tooth substrate 1212, the plurality of first cantilever beams 1225 will undergo corresponding elastic deformation, causing the movable comb tooth electrode 122 to reciprocate in the first direction X, thereby driving the flat plate electrode 13 fixed with the movable comb tooth electrode 122 to move synchronously.

[0140] Please continue to see Fig.11 When there are two connecting parts 1224 of the movable comb-tooth electrode 122, the two connecting parts 1224 are respectively connected to the ends of the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222, and the first comb-tooth substrate 1221, the second comb-tooth substrate 1222 and the two connecting parts 1224 are sequentially connected to form a closed pattern;

[0141] The orthographic projections of the plurality of stationary comb teeth 1213 and the plurality of dynamic comb teeth 1223 on the first base substrate 11 are both located inside the closed pattern; or Fig.12 The figure shows a schematic diagram of another electrostatic drive structure provided by an embodiment of the present disclosure, wherein the orthographic projections of the plurality of static comb teeth 1213 and the plurality of dynamic comb teeth 1223 on the first substrate 11 are both located outside the closed pattern. Fig.12In the embodiment, since the static comb teeth 1213 and the dynamic comb teeth 1223 are arranged outside the closed pattern, the distance between the first comb tooth substrate 1221 and the second comb tooth substrate 1222 is relatively close. At this time, the two connecting parts 1224 are fixed to the groove M through multiple first cantilever beams 1225, which can ensure that the dynamic comb tooth electrode 122 has sufficient displacement space; at the same time, since the third comb tooth substrate 1211 and the fourth comb tooth substrate 1212 and the static comb teeth 1213 fixed thereto are all located outside the closed pattern, the third comb tooth substrate 1211 and the fourth comb tooth substrate 1212 are located on both sides of the closed pattern in the first direction X. At this time, the distance between the third comb tooth substrate 1211 and the fourth comb tooth substrate 1212 is large enough to maintain good insulation and prevent Fig.11 The middle insulating structure 1214 is short-circuited due to voltage breakdown, thereby effectively improving the reliability of the electrostatic driving structure 12.

[0142] like Fig.11 As shown, when the orthographic projections of the plurality of static comb teeth 1213 and the plurality of dynamic comb teeth 1223 on the first base substrate 11 are both located inside the closed pattern, the static comb tooth electrode 1213 further includes:

[0143] The insulating structure 1214 is located between the third comb-tooth substrate 1211 and the fourth comb-tooth substrate 1212 .

[0144] When the orthographic projections of the plurality of stationary comb teeth 1213 and the plurality of dynamic comb teeth 1223 on the first base substrate 11 are all located inside the closed pattern, an insulating structure 1214 is provided between the third comb tooth substrate 1211 and the fourth comb tooth substrate 1212 to prevent the third comb tooth substrate 1211 and the fourth comb tooth substrate 1212 from being easily contacted due to their close distance and causing a short circuit.

[0145] See also Fig.13 and Fig.14 A schematic structural diagram of another electrostatic drive structure provided in an embodiment of the present disclosure.

[0146] The movable comb-tooth electrode 122 has one connecting portion 1224 , and the connecting portion 1224 is connected to the middle position of the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 ;

[0147] like Fig.13 As shown, the third comb tooth substrate 1211 and the fourth comb tooth substrate 1212 are located between the first comb tooth substrate 1221 and the second comb tooth substrate 1222, and the third comb tooth substrate 1211 and the fourth comb tooth substrate 1212 are both divided into two parts by the connecting portion 1224, and the two parts are connected to each other through the connecting line 1215;

[0148] or, as Fig.14As shown, the third comb-tooth substrate 1211 and the fourth comb-tooth substrate 1212 are located on both sides of the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 .

[0149] In the embodiment provided in the present disclosure, by setting the connecting portion 1224 of the movable comb tooth 1223 to one and connecting the connecting portion 1224 to the middle position of the first comb tooth substrate 1221 and the second comb tooth substrate 1222, more movable comb teeth 1223 can be arranged on the first comb tooth substrate 1221 and the second comb tooth substrate 1222, thereby effectively improving the electrostatic adsorption force between the 1213 static comb tooth electrode 121 and the 1223 movable comb tooth electrode 122, thereby improving the reciprocating effect of the movable comb tooth electrode 122 in the first direction X, and further improving the resonant frequency of the torsion of the reflector 212.

[0150] See also Figure 15 to Figure 17 A schematic diagram of another electrostatic drive structure provided by an embodiment of the present disclosure. The first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 have a hollow structure.

[0151] like Fig.15 As shown, the hollow structure in the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 may be a large-sized through hole, and the through hole runs through the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 .

[0152] like Fig.16 , Fig.17 As shown, the hollow structures in the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 may be a plurality of through holes, and the plurality of through holes penetrate the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 .

[0153] The through hole may be in a rectangular, circular, or other shapes, which will not be described in detail here.

[0154] In the embodiment provided in the present disclosure, by making the first comb tooth substrate 1221 and the second comb tooth substrate 1222 have a hollow structure, the weight of the moving comb tooth electrode 122 can be reduced, thereby reducing the inertia of the moving comb tooth electrode 122 in the reciprocating motion and improving the resonant frequency; at the same time, the capacitance structure between the first comb tooth electrode and the first main electrode 131, and between the second comb tooth electrode and the second main electrode 132 can be eliminated, thereby effectively reducing or even eliminating the participating charges between them, and preventing the electrostatic adsorption force generated by the residual charge from hindering the reverse rotation of the galvanometer structure 21.

[0155] See also Figures 18 to 20 , Fig.18 A top view of an isolation layer provided in an embodiment of the present disclosure, Fig.19 and Fig. 20 A bottom view of an isolation layer provided in an embodiment of the present disclosure.

[0156] The galvanometer unit further includes: a first isolation layer 14 located between the moving comb-tooth electrode 122 and the flat electrode 13 , the orthographic projection of the first isolation layer 14 on the first base substrate 11 covers the first comb-tooth substrate 1221 , the second comb-tooth substrate 1222 and a plurality of first cantilever beams 1225 .

[0157] like Figures 18 to 20 As shown, no matter whether the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 have a hollow structure, the orthographic projection of the isolation layer 14 on the first base substrate 11 covers the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 and the plurality of first cantilever beams 1225 .

[0158] The first isolation layer 14 covers the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 , and may cover the entire area or a certain proportion (eg, more than 95%) of the area.

[0159] In the embodiment provided by the present disclosure, by providing a first isolation layer 14 between the moving comb-tooth electrode 122 and the flat plate electrode 13, and allowing the first isolation layer 14 to cover the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 and the plurality of first cantilever beams 1225, the moving comb-tooth electrode 122 can be insulated from the flat plate electrode 13 to prevent short circuit. When the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 have a hollow structure, the flat plate electrode 13 can also be supported by the first isolation layer 14.

[0160] See also Fig.21 and Fig. 22 A top view of a flat plate electrode provided in an embodiment of the present disclosure.

[0161] The flat plate electrode 13 further includes: a plurality of second cantilever beams 133 (i.e., elastic members);

[0162] The orthographic projection of the first main electrode 131 on the first base substrate 11 covers the first comb-tooth substrate 1221 , and the orthographic projection of the second main electrode 132 on the first base substrate 11 covers the second comb-tooth substrate 1222 . The first main electrode 131 and the second main electrode 132 are respectively fixed to the groove M through a plurality of second cantilever beams 133 .

[0163] like Fig.21 As shown, the first main electrode 131 and the second main electrode 132 can be fixed to the groove M through a second cantilever beam 133 respectively, and connected to the positive and negative voltages respectively; the second cantilever beam 133 covers the corresponding first cantilever beam 1225.

[0164] like Fig. 22As shown, the first main electrode 131 and the second main electrode 132 can be fixed to the groove M respectively through two first cantilever beams 1225, and any second cantilever beam 133 connected to the first main electrode 131 and any second cantilever beam 133 connected to the second main electrode 132 are respectively connected to the positive and negative voltages, and the second cantilever beam 133 covers the corresponding first cantilever beam 1225.

[0165] If the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 are hollow structures, the orthographic projection of the first main electrode 131 on the first base substrate 11 covers the first comb-tooth substrate 1221, including covering the hollow structure, and the orthographic projection of the second main electrode 132 on the first base substrate 11 covers the second comb-tooth substrate 1222, including covering the hollow structure, so that the first main electrode 131 and the second main electrode 132 form two flat plate capacitors with the galvanometer structure 21. The bottom view of the flat plate electrode 13 can refer to the bottom view of the isolation layer 14, which will not be repeated here.

[0166] The orthographic projection of the first main electrode 131 on the first base substrate 11 and the first comb-tooth substrate 1221 , and the orthographic projection of the second main electrode 132 on the first base substrate 11 and the second comb-tooth substrate 1222 may mostly overlap or completely overlap like the first isolation layer 14 .

[0167] In the embodiment provided in the present disclosure, by allowing the first main electrode 131 to cover the first comb-tooth substrate 1221 and the second main electrode 132 to cover the second comb-tooth substrate 1222, the first main electrode 131 and the second main electrode 132 can be fixed to the positions of the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 respectively, so that the first main electrode 131 and the second main electrode 132 can reciprocate with the comb-tooth electrode 122 in the first direction X; and by allowing the second cantilever beam 133 to cover the first cantilever beam 1225, the limited space can be reasonably utilized to transmit the positive and negative voltages through the second cantilever beam 133 fixed to the first main electrode 131 and the second main electrode 132, so that the first main electrode 131 and the second main electrode 132 can form two flat plate capacitors with the galvanometer structure 21.

[0168] See also Figure 23 to Figure 25 , Fig.23 A top view of another flat plate electrode provided in an embodiment of the present disclosure, Fig.24 and Fig.25 This is a bottom view of a flat electrode provided by an embodiment of the present disclosure. The first main electrode 131 and the second main electrode 132 also cover a portion of the movable comb teeth 1223 connected to the first comb tooth substrate 1221 and the second comb tooth substrate 1222 respectively.

[0169] Regardless of whether the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 have a hollow structure, the front view of the flat electrode 13 can be as follows Fig.23When the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 do not have a hollow structure, the bottom view of the flat electrode 13 is as shown Fig.24 As shown, when the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 have a hollow structure, the bottom view of the flat electrode 13 is as shown in FIG. Fig.25 shown.

[0170] It should be understood that in order to facilitate viewing of the positional relationship between the first main electrode 131 and the second main electrode 132 and the first comb substrate 1221 and the second comb teeth and the movable comb teeth 1223, Fig.23 and Fig.24 The figure is a bottom view after removing the first isolation layer 14. In practical applications, Fig.23 and Fig.24 The flat electrode 13 shown in FIG. 1 is also the area shown in the bottom view of the isolation layer 14. That is, the first isolation layer 14 can cover the flat electrode 13, so that the flat electrode 13 can be effectively supported, and the side of the flat electrode 13 away from the first isolation layer 14 has a better flatness.

[0171] In the embodiment provided in the present disclosure, by allowing the first main electrode 131 and the second main electrode 132 to also cover a portion of the moving comb tooth electrode 1223 connected to the first comb tooth substrate 1221 and the second comb tooth substrate 1222 respectively, the area of ​​the first main electrode 131 and the second main electrode 132 can be effectively increased, thereby increasing the overlapping area between the first main electrode 131 and the second main electrode 132 and the galvanometer structure 21, increasing the electrostatic adsorption force acting on the galvanometer structure 21, and thereby increasing the resonant frequency of the galvanometer structure 21.

[0172] See also Fig.26 A top view of another flat plate electrode provided in an embodiment of the present disclosure.

[0173] The flat plate electrode 13 also includes: a first auxiliary electrode 134 and a second auxiliary electrode 135; the orthographic projection of the first auxiliary electrode 134 on the first base substrate 11 covers the third comb tooth substrate 1211 and a part of the static comb tooth electrode 1213 connected to the third comb tooth substrate 1211, and the orthographic projection of the second auxiliary electrode 135 on the first base substrate 11 covers the fourth comb tooth substrate 1212 and a part of the static comb teeth 1213 connected to the fourth comb tooth substrate 1212; in the process of the movable comb tooth electrode 122 driving the flat plate electrode 13 to reciprocate, the first auxiliary electrode 134 contacts the first main electrode 131, or the second auxiliary electrode 135 contacts the first main electrode 131.

[0174] See also Fig. 27 and Fig.28 , Fig. 27 A top view of another galvanometer structure twisted toward the second main electrode provided by an embodiment of the present disclosure, Fig.28The embodiments of the present disclosure provide Fig. 27 The front view at the AA' position along the extension direction of the rotation axis is shown in Fig. 27 and Fig.28 The electrostatic driving structure 12 drives the galvanometer structure 21 to move in the opposite direction of the first direction X, so that the first main electrode 131 contacts the first auxiliary electrode 134. At this time, the first auxiliary electrode 134 and the first main electrode 131 carry the same voltage. The first main electrode 131 and the first auxiliary electrode 134 can be regarded as a whole. The corresponding flat plate capacitors have an overlapping area (S1) of the first main electrode 131, the first auxiliary electrode 134 and the galvanometer structure 21, and the corresponding flat plate capacitors have an overlapping area (S2) of the second main electrode 132 and the galvanometer structure 21. This significantly increases the electrostatic adsorption force on the part of the galvanometer structure 21 corresponding to the side corresponding to the first main electrode 131, thereby making the galvanometer structure 21 rotate faster toward the first main electrode 131, thereby effectively improving the rotation speed of the galvanometer structure 21.

[0175] See also Fig.29 and Fig.30 , Fig.29 A top view of another galvanometer structure twisted toward the first main electrode provided by an embodiment of the present disclosure, Fig.30 The embodiments of the present disclosure provide Fig.29 The front view at the AA' position along the extension direction of the rotation axis is shown in Fig.29 and Fig.30 The electrostatic driving structure 12 drives the galvanometer structure 21 to move along the first direction X, so that the second main electrode 132 contacts the second auxiliary electrode 135. At this time, the second auxiliary electrode 135 and the second main electrode 132 carry the same voltage, and the second main electrode 132 and the second auxiliary electrode 135 can be regarded as a whole. The corresponding flat plate capacitors have an overlapping area (S2) of the second main electrode 132 and the second auxiliary electrode 135 and the galvanometer structure 21, and the corresponding flat plate capacitors have an overlapping area (S1) of the first main electrode 131 and the galvanometer structure 21. This significantly increases the electrostatic adsorption force on the part of the galvanometer structure 21 corresponding to the side corresponding to the second main electrode 132, so that the galvanometer structure 21 rotates faster toward the second main electrode 132, thereby effectively improving the rotation speed of the galvanometer structure 21.

[0176] In the process of the electrostatic driving structure 12 driving the first main electrode 131 and the second main electrode 132 to reciprocate in the first direction X, the overlapping area of ​​the first main electrode 131 and the second main electrode 132 with the galvanometer structure 21 also alternates between significantly increasing and decreasing, thereby causing the electrostatic adsorption force acting on the galvanometer structure 21 on both sides of the rotating axis 22 to alternate between significantly increasing and decreasing, thereby increasing the resonance efficiency of the galvanometer structure 21 rotating along the rotating axis 22.

[0177] In the embodiment provided by the present disclosure, the flat plate electrode 13 further includes a first auxiliary electrode 134 and a second auxiliary electrode 135; the orthographic projection of the first auxiliary electrode 134 on the first base substrate 11 covers the third comb tooth substrate 1211 and a part of the static comb teeth 1213 connected to the third comb tooth substrate 1211, and the orthographic projection of the second auxiliary electrode 135 on the first base substrate 11 covers the fourth comb tooth substrate 1212 and a part of the static comb teeth 1213 connected to the fourth comb tooth substrate 1212; in the process of the movable comb tooth electrode 122 driving the flat plate electrode 13 to reciprocate, the first auxiliary electrode 134 contacts with the first main electrode 131, or the second auxiliary electrode 135 contacts with the second main electrode 132, so that the movable comb tooth electrode 122 is moved back and forth. During the complex motion process, when the first main electrode 131 contacts the first auxiliary electrode 134, the electrostatic adsorption force acting on the galvanometer structure 21 on the side corresponding to the first main electrode 131 significantly increases, and the corresponding electrostatic adsorption force acting on the galvanometer structure 21 on the side corresponding to the second main electrode 132 significantly decreases; when the second main electrode 132 contacts the second auxiliary electrode 135, the electrostatic adsorption force acting on the galvanometer structure 21 on the side corresponding to the second main electrode 132 significantly increases, and the corresponding electrostatic adsorption force acting on the galvanometer structure 21 on the side corresponding to the first main electrode 131 significantly decreases, thereby causing the electrostatic adsorption force acting on the galvanometer structure 21 on both sides of the rotating shaft 22 to alternate between significantly increasing and decreasing, thereby increasing the resonance efficiency of the galvanometer structure 21 rotating along the rotating shaft 22.

[0178] See also Fig.31 and Fig.32 , Fig.31 A top view of a first isolation layer provided in an embodiment of the present disclosure, Fig.32 A bottom view of a first isolation layer provided in an embodiment of the present disclosure.

[0179] like Fig.31 As shown, the first isolation layer 14 also covers the first auxiliary electrode 134 and the second auxiliary electrode 135, so that the first auxiliary electrode 134 and the second auxiliary electrode 135 can be isolated from the static comb electrode 121 to prevent short circuit; Fig.31 As shown, the first isolation layer 14 has a plurality of recessed structures M' on one side surface facing the first base substrate 11, and the recessed structures M' cover a plurality of corresponding comb teeth (i.e., each dynamic comb tooth 1223 and each static comb tooth 1213 corresponds to a recessed structure M'), so that the dynamic comb teeth 1223 and the static comb teeth 1213 are both located in the corresponding recessed structures M', which not only allows the adjacent dynamic comb teeth 1223 and the static comb teeth 1213 to be isolated by the first isolation layer 14, but also ensures that when the dynamic comb teeth 1223 and the static comb teeth 1213 are staggered, they maintain a certain distance from the first isolation layer 14 above and do not contact each other, thereby ensuring that the device will not fail.

[0180] When the movable comb-teeth electrode 122 reciprocates in the first direction X, the stationary comb teeth 1213 may be prevented from contacting the movable comb teeth 1223 . When the movable comb teeth 1223 move in the first direction X, the first isolation layer 14 and the first main electrode 131 above the first comb tooth substrate 1221 first contact with the first isolation layer 14 and the first auxiliary electrode 134 above the corresponding third comb tooth substrate 1211. At this time, the movable comb teeth 1223 below cannot continue to move in the first direction X due to the contact hindrance of the upper structure, thereby preventing the static comb teeth 1213 and the movable comb teeth 1223 from contacting and short-circuiting. When the movable comb teeth 1223 move in the opposite direction of the first direction X, the first isolation layer 14 and the second main electrode 132 above the second comb tooth substrate 1222 first contact with the first isolation layer 14 and the second auxiliary electrode 135 above the corresponding fourth comb tooth substrate 1212. At this time, the movable comb teeth 1223 below cannot continue to move in the opposite direction of the first direction X due to the contact hindrance of the upper structure, thereby preventing the static comb teeth 1213 and the movable comb teeth 1223 from contacting and short-circuiting.

[0181] See also Figure 33 to Figure 35 , Fig.33 A top view of a first substrate provided in an embodiment of the present disclosure, Fig.34 The embodiments of the present disclosure provide Fig.33 Cross-sectional view along the BB' direction, Fig.35 A three-dimensional schematic diagram of a first substrate provided in an embodiment of the present disclosure.

[0182] One side surface of the first base substrate 11 has a recessed structure M'. The stationary comb-tooth electrode 121 is located in the recessed structure M. The orthographic projections of the movable comb-tooth electrode 122 and the plate electrode 13 on the first base substrate 11 are located in the recessed structure M'. The orthographic projection of the groove M on the first base substrate 11 coincides with the recessed structure M'.

[0183] In the embodiment provided in the present disclosure, by setting a recessed structure M' on one side surface of the first base substrate 11 and placing the stationary comb-tooth electrode 121 in the recessed structure M', it is convenient to set the stationary comb-tooth electrode 121 and the moving comb-tooth electrode 122 in different layers, so that the moving comb-tooth electrode 122 has sufficient space for movement.

[0184] Based on the same inventive concept, an embodiment of the present disclosure provides a scanning mirror, comprising one or a plurality of galvanometer units as described above arranged in an array.

[0185] In the embodiment provided by the present disclosure, by making the scanning mirror include a plurality of galvanometer units arranged in an array, the maximum torsion angle of each galvanometer unit does not change, but the scanning mirror can achieve a wider range of scanning. In addition, the scanning mirror realized by micro-machining technology has a high degree of integration, and the overall volume change is small, which has less impact on the product.

[0186] Based on the same inventive concept, the present disclosure provides a method for preparing a galvanometer unit. For an embodiment of the galvanometer unit prepared by the preparation method, please refer to the relevant description in the aforementioned galvanometer unit, which will not be repeated here. Fig.36 The preparation method comprises:

[0187] Step S11: forming an electrostatic driving structure on one side of the first substrate;

[0188] Step S12: forming a flat plate electrode on a side of the electrostatic driving structure away from the first substrate to obtain a first substrate; the flat plate electrode includes a first main electrode and a second main electrode arranged along a first direction, and the electrostatic driving structure drives the flat plate electrode to reciprocate in the first direction and is insulated from the electrostatic driving structure;

[0189] Step S13: forming an opening in the second base substrate, and forming a rotating plate in a region corresponding to the opening, to obtain a second substrate having a cavity structure; wherein the cavity structure coincides with the opening, the rotating plate is located in the cavity structure, the rotating plate has a rotating axis, and the rotating axis is fixed to the cavity structure;

[0190] Step S14: After the second substrate is aligned with the first substrate, a reflective layer is deposited on the surface of the rotating plate away from the first substrate, and the reflective layer is patterned to obtain a reflector (a galvanometer structure is formed at this time); wherein, after being grounded, the rotating plate forms two flat plate capacitors with the first main electrode and the second main electrode; the first main electrode and the second main electrode are located on different sides of the rotating axis; in the process of the electrostatic driving structure driving the flat plate electrodes to reciprocate, the overlapping area of ​​the first main electrode and the second main electrode with the rotating plate changes, so that the electrostatic adsorption force of the two flat plate capacitors used for the rotating plate changes, driving the rotating plate to rotate along the rotating axis.

[0191] See also Fig.37 A schematic diagram of manufacturing a galvanometer unit is provided for an embodiment of the present disclosure.

[0192] Step S21 : forming an electrostatic driving structure 12 on one side of the first base substrate 11 .

[0193] Step S22 : forming a flat electrode 13 on a side of the electrostatic driving structure 12 away from the first substrate 11 to obtain a first substrate 1 .

[0194] The plate electrode 13 includes a first main electrode 131 and a second main electrode 132 arranged along the first direction X.

[0195] Step S23: forming an opening in the second base substrate 20;

[0196] Step S24: forming a rotating plate 211 in a region corresponding to the opening, and connecting the rotating plate 211 to the rotating shaft 22 to obtain a second substrate 2 with a cavity structure.

[0197] Step S25: bonding the first substrate 1 and the second substrate 2;

[0198] Step S26 : forming a reflective mirror 212 on a surface of the rotating plate 211 facing away from the first substrate 1 .

[0199] The manufacturing of the galvanometer unit can be completed through the above steps S21 to S26.

[0200] In some embodiments, an electrostatic driving structure is formed on one side of the first substrate, which can be achieved by:

[0201] Etching the first substrate to obtain a first substrate having a recessed structure; one or a plurality of recessed structures arranged in an array may be formed on one side surface of the first substrate by etching;

[0202] Depositing a first metal layer on the bottom surface of the recessed structure, and etching the first metal layer to obtain a stationary comb-tooth electrode;

[0203] A first silicon nitride layer is deposited on a side of the static comb-tooth electrode away from the first substrate, and the first silicon nitride layer is patterned to obtain a second isolation layer covering the signal line of the static comb-tooth electrode; the electrostatic comb-tooth electrodes corresponding to different galvanometer units can be isolated by the second isolation layer and the recessed structure;

[0204] In some embodiments, an isolation structure may be formed between the third comb-tooth substrate and the fourth comb-tooth substrate to prevent the third comb-tooth substrate and the fourth comb-tooth substrate from being short-circuited.

[0205] Depositing a second silicon nitride layer on a side of the first substrate close to the first sub-isolation layer, and patterning the second silicon nitride layer to obtain a second sub-isolation layer covering an area outside the recessed structure; wherein the second isolation layer includes the first sub-isolation layer and the second sub-isolation layer;

[0206] A second metal layer is deposited on a side of the second sub-isolation layer away from the first substrate, and the second metal layer is etched to obtain a moving comb-tooth electrode fixedly connected to the second sub-isolation layer and meshing with the stationary comb-tooth electrode; wherein the moving comb-tooth electrode is used to reciprocate along a first direction relative to the stationary comb-tooth electrode in a plane parallel to the first substrate under the action of electrostatic attraction, and the first direction is the extension direction of the comb teeth.

[0207] See also Fig.38 A schematic diagram of manufacturing an electrostatic drive structure is provided for an embodiment of the present disclosure.

[0208] Step S211: etching the first base substrate 11 to obtain a first base substrate 11 having a recessed structure M′;

[0209] Step S212: depositing a first metal layer on the bottom surface of the recessed structure M';

[0210] Step S213 : etching the first metal layer to obtain the stationary comb-teeth electrode 121 .

[0211] Step S214: depositing a first silicon nitride layer (SiNx) on a side of the stationary comb-tooth electrode away from the first substrate;

[0212] Step S215: patterning the first silicon nitride layer to obtain a first sub-isolation layer covering the signal line of the stationary comb-tooth electrode 121;

[0213] Step 216: depositing a second metal layer on a side of the second sub-isolation layer away from the first substrate 11;

[0214] Step S217 : etching the second metal layer to obtain the movable comb-tooth electrode 122 which is fixedly connected to the second sub-isolation layer and meshes with the stationary comb-tooth electrode 121 .

[0215] In some embodiments, a flat plate electrode is formed on a side of the electrostatic driving structure away from the first substrate, which can be achieved by:

[0216] A third silicon nitride layer is deposited on a side of the moving comb-tooth electrode away from the first base substrate, and the third silicon nitride layer is patterned to obtain a first isolation layer covering the first comb-tooth substrate, the second comb-tooth substrate and the plurality of first cantilever beams; wherein the moving comb-tooth electrode comprises: a first comb-tooth substrate and a second comb-tooth substrate arranged opposite to each other, a plurality of moving comb teeth, a connecting portion connecting the first comb-tooth substrate and the second comb-tooth substrate, and a plurality of first cantilever beams; the plurality of moving comb teeth are arranged along a first direction and extend along a second direction, and the plurality of moving comb teeth are arranged at intervals and fixed on the first comb-tooth substrate and the second comb-tooth substrate; the first direction is perpendicular to the second direction;

[0217] A third metal layer is deposited on a side of the first isolation layer away from the first base substrate, and the third metal layer is patterned to obtain a flat electrode; wherein the first main electrode covers the first comb-tooth substrate, and the second main electrode covers the second comb-tooth substrate.

[0218] After forming the flat plate electrode, a fourth film layer covering the area outside the recessed structure and the second cantilever beam can be formed by depositing on the side of the flat plate electrode away from the first substrate, and exposing the stationary comb-tooth electrode, the dynamic comb-tooth electrode, and the signal line of the flat plate electrode to connect them to the corresponding signal end. Then, a flat layer is formed on the side of the fourth film layer away from the first substrate, and finally the first substrate is obtained.

[0219] See also Fig.39 A schematic diagram of manufacturing a flat plate electrode is provided for an embodiment of the present disclosure.

[0220] Step S221: depositing a third silicon nitride layer on a side of the movable comb-teeth electrode 121 away from the first substrate 11;

[0221] Step S222: patterning the third silicon nitride layer to obtain a first isolation layer 14 covering the first comb-tooth substrate 1221 and the second comb-tooth substrate 1222 and the plurality of first cantilever beams 1225;

[0222] Step S223: depositing a third metal layer on a side of the first isolation layer 14 away from the first substrate 11;

[0223] Step S224 : patterning the third metal layer to obtain the flat plate electrode 13 . The flat plate electrode 13 includes a first main electrode 131 and a second main electrode 132 .

[0224] Based on the same inventive concept, the present disclosure provides a radar system, see Fig.40 The radar system includes:

[0225] Laser emitting component 4001, used for emitting laser;

[0226] Reflection unit 4002;

[0227] As the scanning mirror 4003 described above, the reflection unit 4002 reflects the laser to the scanning mirror 4003, and the scanning mirror 4003 scans the obstacle;

[0228] A focusing lens 4004, used for focusing the laser reflected by the obstacle;

[0229] A beam receiving component 4005, used to receive the laser focused by the focusing lens 4004;

[0230] The control component 4006 is used to form an image of the obstacle according to the signal fed back by the beam receiving component 4005.

[0231] 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.

[0232] Obviously, those skilled in the art can make various changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations 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 galvanometer unit, comprising a first substrate and a second substrate bonded together, wherein the first substrate has a groove, the second substrate has a cavity structure, the second substrate comprises a galvanometer structure accommodated in the cavity structure, the galvanometer structure has a rotation axis, and the rotation axis is fixed to the cavity structure, wherein: The first substrate comprises: a first substrate base plate; An electrostatic driving structure, located on one side of the first substrate; a flat plate electrode, located on a side of the electrostatic drive structure away from the first substrate, and insulated from the electrostatic drive structure, wherein the electrostatic drive structure drives the flat plate electrode to reciprocate in a first direction; the flat plate electrode comprises a first main electrode and a second main electrode located on different sides of the rotation axis; wherein the first direction is perpendicular to an extension direction of the rotation axis; During the reciprocating motion, the overlapping areas of the first main electrode, the second main electrode and the galvanometer structure change, so that the electrostatic attraction acting on the galvanometer structure changes, driving the galvanometer structure to rotate along the rotation axis.

2. The galvanometer unit according to claim 1, wherein: After being grounded, the galvanometer structure forms two flat plate capacitors with the first main electrode and the second main electrode respectively.

3. The galvanometer unit according to claim 1, wherein: The electrostatic driving structure comprises: a stationary comb-tooth electrode and a movable comb-tooth electrode meshing with each other, wherein the movable comb-tooth electrode is used to reciprocate relative to the stationary comb-tooth electrode in a plane parallel to the first substrate substrate along the first direction under the action of electrostatic attraction between the movable comb-tooth electrode and the stationary comb-tooth electrode, wherein the first direction is the extension direction of the comb teeth; The stationary comb-tooth electrode is fixed to one side surface of the first substrate, the moving comb-tooth electrode is fixed to the groove by an elastic member, the moving comb-tooth electrode and a side of the stationary comb-tooth electrode away from the first substrate are located in the same plane, and a side of the stationary comb-tooth electrode close to the first substrate is in contact with the first substrate, a side of the moving comb-tooth electrode close to the first substrate is suspended, and the flat electrode is fixed to the surface of the moving comb-tooth electrode away from the first substrate.

4. The galvanometer unit according to claim 3, wherein: The movable comb-tooth electrode comprises: a first comb-tooth substrate and a second comb-tooth substrate arranged opposite to each other, a plurality of movable comb teeth, a connecting portion connecting the first comb-tooth substrate and the second comb-tooth substrate, and a plurality of first cantilever beams; The first comb tooth substrate and the second comb tooth substrate are arranged along the first direction and extend along the second direction, and the connecting portion or the first comb tooth substrate and the second comb tooth substrate are respectively fixed to the groove through the multiple first cantilever beams; the multiple movable comb teeth extend along the first direction and are arranged along the second direction, and the multiple movable comb teeth are spaced and fixed on the first comb tooth substrate and the second comb tooth substrate; the first direction is perpendicular to the second direction.

5. The galvanometer unit according to claim 4, wherein: The stationary comb-tooth electrode comprises: a third comb-tooth substrate and a fourth comb-tooth substrate arranged opposite to each other, and a plurality of stationary comb teeth, wherein the third comb-tooth substrate is insulated from the fourth comb-tooth substrate; The third comb tooth substrate and the fourth comb tooth substrate are arranged along the first direction and extend along the second direction; the multiple static comb teeth extend along the first direction and are arranged along the second direction, the multiple static comb teeth are arranged at intervals and fixed on the third comb tooth substrate and the fourth comb tooth substrate, and the static comb teeth fixed on the third comb tooth substrate are meshed with the dynamic comb teeth fixed on the first comb tooth substrate, and the static comb teeth fixed on the fourth comb tooth substrate are staggered with the dynamic comb teeth fixed on the second comb tooth substrate.

6. The galvanometer unit according to claim 5, wherein: There is one connecting portion, and the connecting portion is connected to the middle position of the first comb tooth substrate and the second comb tooth substrate; The third comb-tooth substrate and the fourth comb-tooth substrate are located between the first comb-tooth substrate and the second comb-tooth substrate, and the third comb-tooth substrate and the fourth comb-tooth substrate are both divided into two parts by the connecting part, and the two parts are connected to each other through the connecting line; Alternatively, the third comb-tooth substrate and the fourth comb-tooth substrate are located on both sides of the first comb-tooth substrate and the second comb-tooth substrate.

7. The galvanometer unit according to claim 5, wherein: There are two connecting parts, and the two connecting parts are respectively connected to the ends of the first comb tooth substrate and the second comb tooth substrate, and the first comb tooth substrate, the second comb tooth substrate and the two connecting parts are sequentially connected to form a closed pattern; The orthographic projections of the plurality of stationary comb teeth and the plurality of dynamic comb teeth on the first substrate are both located inside the closed pattern; Alternatively, the orthographic projections of the plurality of stationary comb teeth and the plurality of dynamic comb teeth on the first base substrate are both located outside the closed pattern.

8. The galvanometer unit according to claim 7, wherein: When the orthographic projections of the plurality of stationary comb teeth and the plurality of dynamic comb teeth on the first substrate are both located inside the closed pattern, the stationary comb tooth electrode further includes: The insulating structure is located between the third comb-tooth substrate and the fourth comb-tooth substrate.

9. The galvanometer unit according to any one of claims 4 to 8, wherein: The first comb-tooth substrate and the second comb-tooth substrate have a hollow structure.

10. The galvanometer unit according to any one of claims 4 to 8, wherein: The first substrate further includes: a first isolation layer located between the moving comb-tooth electrode and the flat plate electrode, wherein the orthographic projection of the first isolation layer on the first base substrate covers the first comb-tooth substrate, the second comb-tooth substrate and the plurality of first cantilever beams.

11. The galvanometer unit according to any one of claims 4 to 10, wherein: The flat plate electrode further includes: a plurality of second cantilever beams; The orthographic projection of the first main electrode on the first base substrate covers the first comb-tooth substrate, the orthographic projection of the second main electrode on the first base substrate covers the second comb-tooth substrate, and the first main electrode and the second main electrode are respectively fixed to the groove through the plurality of second cantilever beams.

12. The galvanometer unit according to claim 11, wherein: The first main electrode and the second main electrode further cover a portion of the movable comb teeth connected to the first comb tooth substrate and the second comb tooth substrate, respectively.

13. The galvanometer unit according to claim 12, wherein: The flat plate electrode also includes: a first auxiliary electrode and a second auxiliary electrode; the orthographic projection of the first auxiliary electrode on the first base substrate covers the third comb tooth substrate and a part of the stationary comb teeth connected to the third comb tooth substrate, and the orthographic projection of the second auxiliary electrode on the first base substrate covers the fourth comb tooth substrate and a part of the stationary comb teeth connected to the fourth comb tooth substrate; in the process of the movable comb tooth electrode driving the flat plate electrode to reciprocate, the first auxiliary electrode contacts the first main electrode, or the second auxiliary electrode contacts the first main electrode.

14. The galvanometer unit according to claim 13, wherein: The first isolation layer also covers the first auxiliary electrode and the second auxiliary electrode. A surface of the first isolation layer facing the first substrate has a plurality of recessed structures, and the recessed structures cover a plurality of corresponding comb teeth.

15. The galvanometer unit according to any one of claims 1 to 14, wherein: A side surface of the first substrate has a concave structure overlapping with the groove, and the stationary comb-tooth electrode is located in the concave structure.

16. The galvanometer unit according to any one of claims 1 to 15, wherein: The galvanometer structure further includes: a second substrate, the second substrate having an opening, wherein the opening coincides with the cavity structure; A rotating plate, fixedly connected to the rotating shaft, and configured to rotate along the rotating shaft under the action of the electrostatic attraction of the two flat plate capacitors; The reflector is located on a side surface of the rotating plate away from the first substrate and is fixed to the rotating plate.

17. A scanning mirror, comprising one or a plurality of galvanometer units arranged in an array according to any one of claims 1 to 16.

18. A method for preparing a galvanometer unit, wherein: include: An electrostatic driving structure is formed on one side of the first substrate; A flat plate electrode is formed on a side of the electrostatic driving structure away from the first substrate to obtain a first substrate; the flat plate electrode includes a first main electrode and a second main electrode arranged along a first direction, and the electrostatic driving structure drives the flat plate electrode to reciprocate in the first direction and is insulated from the electrostatic driving structure; An opening is formed in the second base substrate, and a rotating plate is formed in a region corresponding to the opening, so as to obtain a second substrate having a cavity structure; wherein the cavity structure coincides with the opening, the rotating plate is located in the cavity structure, the rotating plate has a rotating shaft, and the rotating shaft is fixed to the cavity structure; After the second substrate is aligned with the first substrate, a reflective layer is deposited on the surface of the rotating plate away from the first substrate, and the reflective layer is patterned to obtain a reflector; wherein, after being grounded, the rotating plate forms two flat plate capacitors with the first main electrode and the second main electrode; the first main electrode and the second main electrode are located on different sides of the rotating axis; in the process of the electrostatic driving structure driving the flat plate electrodes to reciprocate, the overlapping areas of the first main electrode and the second main electrode with the rotating plate change, so that the electrostatic attraction forces of the two flat plate capacitors acting on the rotating plate respectively change, thereby driving the rotating plate to rotate along the rotating axis.

19. The preparation method according to claim 18, wherein: On one side of the first substrate, an electrostatic driving structure is formed, including: Etching the first substrate to obtain a first substrate having a recessed structure; Depositing a first metal layer on the bottom surface of the recessed structure, and etching the first metal layer to obtain a stationary comb-tooth electrode; Depositing a first silicon nitride layer on a side of the stationary comb-tooth electrode away from the first substrate, and patterning the first silicon nitride layer to obtain a first sub-isolation layer covering the connection line of the stationary comb-tooth electrode; Depositing a second silicon nitride layer on a side of the first substrate close to the first sub-isolation layer, and patterning the second silicon nitride layer to obtain a second sub-isolation layer covering an area outside the recessed structure; wherein the second isolation layer includes the first sub-isolation layer and the second sub-isolation layer; A second metal layer is deposited on a side of the second sub-isolation layer away from the base substrate, and the second metal layer is etched to obtain the movable comb-tooth electrode fixedly connected to the second sub-isolation layer and meshing with the stationary comb-tooth electrode; wherein the movable comb-tooth electrode is used to reciprocate along the first direction relative to the stationary comb-tooth electrode in a plane parallel to the first base substrate under the action of electrostatic attraction, and the first direction is the extension direction of the comb teeth.

20. The preparation method according to claim 19, wherein A flat plate electrode is formed on a side of the electrostatic drive structure away from the first substrate, including: A third silicon nitride layer is deposited on a side of the movable comb-tooth electrode away from the first substrate, and the third silicon nitride layer is patterned to obtain a first isolation layer covering the first comb-tooth substrate and the second comb-tooth substrate and a plurality of first cantilever beams; wherein the movable comb-tooth electrode comprises: a first comb-tooth substrate and a second comb-tooth substrate arranged opposite to each other, a plurality of movable comb teeth, a connecting portion connecting the first comb-tooth substrate and the second comb-tooth substrate, and a plurality of first cantilever beams; the plurality of movable comb teeth are arranged along the first direction and extend along the second direction, and the plurality of movable comb teeth are arranged at intervals and fixed on the first comb-tooth substrate and the second comb-tooth substrate; the first direction is perpendicular to the second direction; A third metal layer is deposited on a side of the first isolation layer away from the base substrate, and the third metal layer is patterned to obtain the flat electrode; wherein the first main electrode covers the first comb-tooth substrate, and the second main electrode covers the second comb-tooth substrate.

21. A radar system, wherein: include: A laser emitting component, used for emitting laser; Reflection unit; The scanning mirror as claimed in claim 17, wherein the reflection unit reflects the laser to the scanning mirror, and the obstacle is scanned by the scanning mirror; A focusing lens, used for focusing the laser reflected by the obstacle; A beam receiving component, used for receiving the laser focused by the focusing lens; The control component is used to form an image of the obstacle according to the signal fed back by the beam receiving component.

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