Electrostatically driven micro galvanometer and preparation method thereof

Abstract

The invention relates to the technical field of micro galvanometers, and discloses an electrostatic drive micro galvanometer and a preparation method thereof. The electrostatic driving micro galvanometer comprises a first functional structure layer, a second functional structure layer and a third functional structure layer which are sequentially stacked and are in insulated connection; the first functional structure layer comprises a first accommodating space, a first driving structure and a second driving structure; the second functional structure layer comprises a torsional reflector assembly suspended above the first accommodating space, and the reflecting surface of the torsional reflector assembly deviates from the first functional structure layer; the third driving structure of the third functional structure layer corresponds to the first driving structure, the fourth driving structure corresponds to the second driving structure, and the second accommodating space corresponds to the first accommodating space. A sandwich type structure is adopted, the first functional structure layer and the third functional structure layer which are provided with fixed driving structures are arranged on the upper side and the lower side of the second functional structure layer provided with the movable torsional reflector assembly respectively, the scanning angle of the micro galvanometer is increased, and interference of unbalanced motion is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of micro-vibration mirrors, and in particular to an electrostatically driven micro-vibration mirror and a preparation method thereof. Background Art

[0002] A micro-vibration mirror (MEMS micro-vibration mirror) is a miniature drivable mirror based on Micro Electro Mechanical Systems (MEMS) technology. Depending on the driving principle, micro-vibration mirrors can be divided into four categories: electromagnetic drive, piezoelectric drive, electrothermal drive, and electrostatic drive. Among them, electrostatic drive micro-vibration mirrors are the most common in practical applications due to their simple structure, mature technology, and low power consumption. An electrostatically driven micro-vibration mirror includes a fixed electrode and a movable mirror. The movable mirror usually includes a movable electrode, a torsion beam, and a mirror connected in sequence. The movable electrode is set close to the fixed electrode. The basic principle is to apply a voltage between the fixed electrode and the movable electrode, and use the electrostatic force interaction to drive the deflection of the mirror, thereby achieving optical control.

[0003] Electrostatically driven micro-vibration mirrors can be divided into three types based on their driver structures: parallel plate, planar comb, and vertical comb. The vertical comb structure provides greater out-of-plane torque than the other two, and does not suffer from the electrostatic pull-in effect of the parallel plate structure, making it more widely used. However, conventional vertical comb electrostatically driven micro-vibration mirrors, whose vertical comb drive structure is distributed on one side of the plane where the reflector is located, still suffer from insufficient scanning angles. Therefore, their application is significantly limited in scenarios requiring large scanning angles. Furthermore, the vertical comb drive structure is distributed on one side of the plane where the reflector is located, and the resultant electrostatic force is not zero when the reflector is deflected around the torsion beam for scanning motion. This can cause the reflector and its torsion axis to deviate from their equilibrium position, thereby interfering with the scanning process of the micro-vibration mirror and affecting its reliability. Summary of the Invention

[0004] In view of this, the present invention provides an electrostatically driven micro-vibration mirror and a preparation method thereof to solve the problems of insufficient scanning angle of the existing micro-vibration mirror during torsional scanning and the reflector easily deviating from the equilibrium position.

[0005] In a first aspect, the present invention provides an electrostatically driven micro-vibration mirror, comprising: a first functional structure layer, a second functional structure layer, and a third functional structure layer stacked in sequence and insulated from each other;

[0006] The first functional structure layer includes a first driving structure and a second driving structure, the first driving structure and the second driving structure are spaced and insulated from each other in a first direction, and form a first accommodating space;

[0007] The second functional structure layer includes a torsion reflector assembly, which is suspended above the first accommodating space; the torsion reflector assembly includes a first transmission structure, a reflector structure, and a second transmission structure connected in sequence in a second direction, the second direction forming a preset angle with the first direction, the reflective surface of the reflector structure facing away from the first functional structure layer, the first transmission structure and the second transmission structure are collinearly arranged, and the straight line on which they are located passes through the center of the reflector structure; the first drive structure and the second drive structure are symmetrically arranged relative to the projection point of the center of the reflector structure on the plane of the first functional structure layer;

[0008] The third functional structure layer includes a third drive structure and a fourth drive structure that are spaced apart and insulated. The third drive structure and the first drive structure are arranged vertically corresponding to each other, and the fourth drive structure and the second drive structure are arranged vertically corresponding to each other. A second accommodating space is formed between the third drive structure and the fourth drive structure. The second accommodating space corresponds vertically to the first accommodating space to provide a deflection space for the torsional reflector assembly.

[0009] The first driving structure and the fourth driving structure are suitable for generating an electrostatic adsorption force on the torsional reflector assembly under the action of an equal external non-zero voltage, so that the torsional reflector assembly is deflected along a first torsional direction; or, the second driving structure and the third driving structure are suitable for generating an electrostatic adsorption force on the torsional reflector assembly under the action of an equal external non-zero voltage, so that the torsional reflector assembly is deflected along a second torsional direction, and the first torsional direction and the second torsional direction are opposite.

[0010] Beneficial effects: The electrostatically driven micro-vibration mirror of the present invention adopts a "sandwich"-like structural design. A first functional structure layer and a third functional structure layer with a fixed driving structure are respectively arranged on the upper and lower sides of the second functional structure layer with a movable torsional reflector assembly, which greatly increases the driving force of the micro-vibration mirror, thereby increasing the scanning angle of the micro-vibration mirror; moreover, since the driving structures arranged on the upper and lower sides are symmetrically distributed on both sides of the plane where the torsional reflector assembly is located, the electrostatic forces acting on the torsional reflector assembly or the reflector structure are equal in magnitude and opposite in direction, which avoids the torsional axis from deviating from the equilibrium position, thereby avoiding the interference caused by unbalanced motion. That is, the electrostatically driven micro-vibration mirror of the present invention can not only avoid the interference caused by unbalanced motion, ensure the scanning stability of the micro-vibration mirror, but also provide a larger scanning angle.

[0011] In an optional embodiment, the first transmission structure includes a first torsion beam and a first movable comb tooth structure and a third movable comb tooth structure respectively arranged on the outer periphery of the first torsion beam in a first direction; the second transmission structure includes a second torsion beam and a second movable comb tooth structure and a fourth movable comb tooth structure respectively arranged on the outer periphery of the second torsion beam in the first direction; in the first direction, the first movable comb tooth structure and the second movable comb tooth structure face one side of the first drive structure and the third drive structure, and the third movable comb tooth structure and the fourth movable comb tooth structure face one side of the second drive structure and the fourth drive structure;

[0012] The first driving structure includes a first fixed comb tooth structure and a second fixed comb tooth structure, the first fixed comb tooth structure and the first movable comb tooth structure are vertically staggered, and the second fixed comb tooth structure and the second movable comb tooth structure are vertically staggered; the second driving structure includes a third fixed comb tooth structure and a fourth fixed comb tooth structure, the third fixed comb tooth structure and the third movable comb tooth structure are vertically staggered, and the fourth fixed comb tooth structure and the fourth movable comb tooth structure are vertically staggered;

[0013] The third driving structure includes a fifth fixed comb tooth structure and a sixth fixed comb tooth structure, the fifth fixed comb tooth structure and the first fixed comb tooth structure are arranged in correspondence with each other up and down, and the sixth fixed comb tooth structure and the second fixed comb tooth structure are arranged in correspondence with each other up and down; the fourth driving structure includes a seventh fixed comb tooth structure and an eighth fixed comb tooth structure, the seventh fixed comb tooth structure and the third fixed comb tooth structure are arranged in correspondence with each other up and down, and the eighth fixed comb tooth structure and the fourth fixed comb tooth structure are arranged in correspondence with each other up and down.

[0014] Beneficial effects: The first drive structure, second drive structure, third drive structure, fourth drive structure, and first transmission structure and second transmission structure of the present invention are all configured as comb tooth structures. The comb tooth structures can generate a greater driving force under the same area, and the driving force is more stable. The first drive structure and the third drive structure located on the same side of the torsional reflector assembly in the first direction of the present invention are correspondingly arranged up and down, and both correspond to the first movable comb tooth structure and the second movable comb tooth structure being configured as two-part fixed comb tooth structures in the second direction. At the same time, the second drive structure and the fourth drive structure located on the other side of the torsional reflector assembly in the first direction are also correspondingly configured as two-part fixed comb teeth.

[0015] In an optional embodiment, the first fixed comb tooth structure and the second fixed comb tooth structure are connected, the third fixed comb tooth structure and the fourth fixed comb tooth structure are connected; the fifth fixed comb tooth structure and the sixth fixed comb tooth structure are connected, and the seventh fixed comb tooth structure and the eighth fixed comb tooth structure are connected.

[0016] Beneficial Effects: In the present invention, four fixed comb-tooth structures are formed in a matrix arrangement in the first functional structure layer. Similarly, four fixed comb-tooth structures are formed in a matrix arrangement in the third functional structure layer. Two fixed comb-tooth structures located on the same side in the first direction are connected to each other. Furthermore, the fixed comb-tooth structures can be connected to an external power supply, thereby achieving equal external voltages for the two fixed comb-tooth structures on the same side. Regarding the selection of the drive structure, it is sufficient to select two fixed comb-tooth structures located on different sides of the torsion reflector assembly in the first horizontal direction, and the two drive structures must also be located on different sides of the torsion reflector assembly in the vertical direction.

[0017] In an optional embodiment, the reflector structure includes a main structure and a reflective layer. The main structure is integrally formed with the first transmission structure and the second transmission structure. The reflective layer is arranged on a side surface of the main structure opposite to the first functional structure layer.

[0018] Beneficial Effects: The present invention's integrally connected main structure, first transmission structure, and second transmission structure facilitate the formation of a highly consistent torsional reflector assembly. The reflective layer, located on the side of the main structure facing away from the first functional structure layer, facilitates better directional deflection of external light, enabling optical manipulation such as graphical scanning and image scanning.

[0019] In an optional embodiment, a side of the main structure facing away from the reflective layer is formed by inward depression of a surface portion of the main structure into grooves and ribs.

[0020] Beneficial effects: The present invention forms grooves and ribs on the back side of the reflector structure. Etching away part of the grooves can reduce the weight of the reflector structure and increase the scanning frequency; the retained ribs help to increase the rigidity of the reflector structure and prevent the reflector structure from deforming too much, so that the reflector structure can achieve stable deflection under the drive of the first torsion beam and the second torsion beam.

[0021] In an optional embodiment, the first functional structure layer further includes a first substrate and a first insulating layer, the first insulating layer is disposed on a side surface of the first substrate, the first driving structure and the second driving structure are integrally formed on a side of the first substrate facing away from the first insulating layer, and the first accommodating space penetrates the first substrate;

[0022] The second functional structure layer further includes a second substrate and a second insulating layer. The second insulating layer is disposed on a surface of the second substrate adjacent to the first functional structure layer to connect to the first substrate. Both ends of the torsional reflector assembly are connected to the second substrate to be suspended above the first accommodating space.

[0023] The third functional structure layer also includes a third substrate and a third insulating layer. The third insulating layer is arranged on a side surface of the third substrate close to the second functional structure layer to be connected to the second substrate. The third driving structure and the fourth driving structure are integrally formed on the third substrate and suspended above the first driving structure and the second driving structure. The second accommodating space passes through the third substrate and the third insulating layer to form a torsional space of the torsional reflector assembly with the first accommodating space.

[0024] Beneficial effects: In the present invention, the first substrate is used to realize the fixed installation of the first functional structure layer, and a first insulating layer is arranged on one side surface of the first substrate, which is suitable for realizing insulation with an external structure such as a substrate layer; the second functional structure layer includes a second substrate and a second insulating layer arranged on one side surface of the second substrate, and the second functional structure layer is bonded to the first functional structure layer with the second insulating layer facing the first substrate, that is, insulation is realized between the first substrate and the second substrate through the second insulating layer; the third insulating layer of the third functional structure layer is arranged between the third substrate and the second substrate to realize insulation.

[0025] In an optional embodiment, the first functional structure layer also includes a first electrode, which is arranged on the first substrate, and the first electrode is exposed on the second substrate, and the first electrode is suitable for connecting an external power supply and the first substrate; the second functional structure layer also includes a second electrode, which is arranged on the second substrate, and the second electrode is exposed on the third substrate, and the second electrode is suitable for grounding the torsional reflector assembly; the third functional structure layer also includes a third electrode, which is arranged on the third substrate, and the third electrode is suitable for connecting an external power supply and the third substrate.

[0026] Beneficial effect: The first electrode is set corresponding to the specific structure of the first substrate. For example, if the first substrate is divided into two sub-substrates, one first electrode is set on each sub-substrate; if the first substrate is divided into four sub-substrates, four first electrodes are set, so as to simply set a corresponding separate electrode for each fixed comb structure, thereby improving fault tolerance. Similarly, the number of third electrodes is also set according to the number of sub-substrates of the third substrate. For the second substrate, one second electrode or two second electrodes can be set, as long as grounding is achieved. The first functional structure layer, the second functional structure layer and the third functional structure layer have a stepped structure in the edge area to expose the electrodes of the lower layer, which is convenient for external wires to connect the functional structure layer to the power supply.

[0027] In an optional embodiment, it further includes a substrate layer, which is arranged on a side of the first functional structure layer facing away from the second functional structure layer.

[0028] Beneficial effect: The first functional structure layer, the second functional structure layer and the third functional structure layer are stacked in sequence on the substrate layer to achieve support for the three functional structure layers.

[0029] In a second aspect, the present invention further provides a method for preparing an electrostatically driven micro-vibration mirror, which is used to prepare the above-mentioned electrostatically driven micro-vibration mirror, comprising:

[0030] forming a first functional structure layer, the first functional structure layer including a first driving structure and a second driving structure, the first driving structure and the second driving structure being spaced apart and insulated from each other in a first direction, and forming a first accommodating space;

[0031] The second functional structure layer is arranged on one side of the first functional structure layer, the second functional structure layer includes a torsion reflector assembly, and the torsion reflector assembly is suspended above the first accommodating space; the torsion reflector assembly includes a first transmission structure, a reflector structure, and a second transmission structure connected in sequence in a second direction, the second direction forms a preset angle with the first direction, the reflective surface of the reflector structure faces away from the first functional structure layer, the first transmission structure and the second transmission structure are arranged collinearly, and the straight line on which they are located passes through the center of the reflector structure; the first drive structure and the second drive structure are symmetrically arranged relative to the projection point of the center of the reflector structure on the plane of the first functional structure layer;

[0032] The third functional structure layer is arranged on the side of the second functional structure layer away from the first functional structure layer. The third functional structure layer includes a third driving structure and a fourth driving structure that are spaced and insulated. The third driving structure and the first driving structure are arranged correspondingly to each other in the upper and lower directions, and the fourth driving structure and the second driving structure are arranged correspondingly to each other in the upper and lower directions. A second accommodating space is formed between the third driving structure and the fourth driving structure. The second accommodating space corresponds to the first accommodating space in the upper and lower directions to provide a deflection space for the torsional reflector assembly.

[0033] Beneficial Effects: In the electrostatically driven micro-vibration mirror fabrication method of the present invention, each functional structure layer can be formed by etching a silicon wafer to form the desired functional structure, and the three functional structure layers are insulated and stacked. By flexibly energizing the drive structures in the upper and lower layers and configuring the deflection drive of the torsional reflector assembly in the middle layer, the scanning angle of the middle torsional reflector assembly can be effectively increased while avoiding any balance deviation of the torsional reflector assembly, ensuring scanning stability and ultimately improving the scanning performance of the electrostatically driven micro-vibration mirror.

[0034] In an optional embodiment, before forming the first functional structure layer, the method further includes: providing a substrate layer;

[0035] Forming the first functional structure layer includes: forming a first insulating layer on one side surface of the substrate layer, forming an initial first base on the first insulating layer; forming a first electrode on the initial first base; etching and removing a portion of the initial first base to form a first base, a first accommodating space, a first driving structure, and a second driving structure, wherein the first accommodating space passes through the initial first base;

[0036] Arranging the second functional structure layer on one side of the first functional structure layer includes: providing an initial second substrate; forming a second insulating layer on a surface of one side of the initial second substrate; etching a side of the initial second substrate having the second insulating layer to form a main structure of the reflector structure; flipping the initial second substrate having the main structure so that the second insulating layer is fixed on the first substrate facing the first functional structure layer, and the initial second substrate covers the first electrode; forming a reflective layer and a second electrode on a side of the initial second substrate away from the first functional structure layer, the reflective layer being arranged corresponding to the main structure; etching a side of the initial second substrate away from the first functional structure layer to form a first transmission structure and a second transmission structure, so that the torsional reflector assembly is suspended and at least a portion of the first electrode is exposed;

[0037] Arranging the third functional structure layer on the side of the second functional structure layer away from the first functional structure layer includes: providing an initial third substrate; forming a third insulating layer on the surface of one side of the initial third substrate; arranging the initial third substrate with the third insulating layer on the second functional structure layer, with the third insulating layer facing the second functional structure layer and covering the second electrode; arranging the third electrode on the side of the initial third substrate away from the second functional structure layer; etching and removing part of the initial third substrate and the third insulating layer to form a third substrate, a second accommodating space, a third driving structure and a fourth driving structure, and exposing part of the second electrode, and the first accommodating space passes through the initial third substrate and the third insulating layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 1 is a schematic top view of an electrostatically driven micro-vibration mirror according to an embodiment of the present invention;

[0040] Figure 2 1 is a bottom-up schematic diagram of an electrostatically driven micro-vibration mirror according to an embodiment of the present invention;

[0041] Figure 3 The electrostatically driven micro-vibration mirror of the embodiment of the present invention is Figure 1 Schematic diagram of the cross section from A1 to A2, A3 to A4, and A5 to A6;

[0042] Figure 4 It is along Figure 1Schematic cross-sectional view of the electrostatically driven micro-vibration mirror in a force-driven mode, taken from B1 to B2, B3 to B4, and B5 to B6;

[0043] Figure 5 It is along Figure 3 Schematic cross-sectional view of the electrostatically driven micro-vibration mirror in another force-driven mode, taken from B1 to B2, B3 to B4, and B5 to B6;

[0044] Figure 6 1 is a flow chart of a method for preparing an electrostatically driven micro-vibration mirror according to an embodiment of the present invention;

[0045] Figure 7 1 is a schematic structural diagram of an SOI substrate according to an embodiment of the present invention;

[0046] Figure 8 is a structural schematic diagram of forming a first electrode on an initial first substrate according to an embodiment of the present invention;

[0047] Figure 9 is a structural schematic diagram of forming a first accommodating space in an initial first substrate according to an embodiment of the present invention;

[0048] Figure 10 is a schematic structural diagram of an embodiment of the present invention after a first functional structure layer is formed on a substrate layer;

[0049] Figure 11 2 is a schematic structural diagram of an initial second substrate and a second insulating layer according to an embodiment of the present invention;

[0050] Figure 12 is a schematic structural diagram of an embodiment of the present invention after the main structure of the reflector structure is formed on the initial second substrate;

[0051] Figure 13 It is a structural schematic diagram of an embodiment of the present invention in which an initial second substrate having a main structure is disposed on a first functional structure layer.

[0052] Figure 14 is a schematic structural diagram of an embodiment of the present invention after a second electrode and a reflective layer are formed on an initial second substrate;

[0053] Figure 15 is a schematic structural diagram of an embodiment of the present invention after a torsional reflector assembly is formed by etching on an initial second substrate;

[0054] Figure 16 2 is a schematic structural diagram of an electrostatically driven micro-vibration mirror including a substrate layer, a first functional structure layer, and a second functional structure layer after removing the exposed second insulating layer and exposing the first electrode according to an embodiment of the present invention;

[0055] Figure 17It is a schematic structural diagram of fixing the initial third substrate and the third insulating layer to the second functional structure layer according to an embodiment of the present invention.

[0056] Figure 18 is a schematic structural diagram of an embodiment of the present invention after a third electrode is formed on an initial third substrate;

[0057] Figure 19 is a structural schematic diagram of an embodiment of the present invention after a second accommodation space is formed on an initial third substrate;

[0058] Figure 20 is a structural schematic diagram of an embodiment of the present invention after a third driving structure and a fourth driving structure are formed on an initial third substrate;

[0059] Figure 21 It is a structural schematic diagram of an electrostatically driven micro-vibration mirror formed after the exposed third insulating layer is removed by over-etching and the second electrode is exposed in an embodiment of the present invention.

[0060] Description of reference numerals:

[0061] 1. First functional structure layer; 11. First driving structure; 111. First fixed comb structure; 112. Second fixed comb structure; 12. Second driving structure; 121. Third fixed comb structure; 122. Fourth fixed comb structure; 13. First accommodating space; 14. First substrate; 14a. First sub-substrate; 14b. Second sub-substrate; 14c. Third sub-substrate; 14d. Fourth sub-substrate; 15. First insulating layer; 16. First electrode;

[0062] 2. Second functional structure layer; 21. First transmission structure; 211. First torsion beam; 212. First movable comb structure; 213. Third movable comb structure; 22. Reflector structure; 221. Main body structure; 2211. Groove; 2212. Rib; 222. Reflective layer; 23. Second transmission structure; 231. Second torsion beam; 232. Second movable comb structure; 233. Fourth movable comb structure; 24. Second substrate; 25. Second insulating layer; 26. Second electrode;

[0063] 3. Third functional structure layer; 31. Third driving structure; 311. Fifth fixed comb structure; 312. Sixth fixed comb structure; 32. Fourth driving structure; 321. Seventh fixed comb structure; 322. Eighth fixed comb structure; 33. Second accommodating space; 34. Third substrate; 34a. Fifth sub-substrate; 34b. Sixth sub-substrate; 34c. Seventh sub-substrate; 34d. Eighth sub-substrate; 35. Third insulating layer; 36. Third electrode;

[0064] 4. Substrate layer;

[0065] 100, initial first matrix; 200, initial second matrix; 300, initial third matrix. DETAILED DESCRIPTION

[0066] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are intended only to illustrate the present invention and are not intended to limit it. It should also be noted that, for ease of description, the drawings only illustrate some, but not all, structures relevant to the present invention. In the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion about the present invention. The accompanying drawings illustrate various schematic diagrams of structures according to embodiments of the present invention. These figures are not drawn to scale; certain details may be exaggerated or omitted for clarity. The shapes, relative sizes, and positional relationships of various regions and layers shown in the figures are merely illustrative and may vary in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions based on actual needs. In the context of the present invention, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or an intervening layer / element may exist between them. In addition, if a layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element would be "below" the other layer / element.

[0067] MEMS micro-mirror is an optical MEMS device that is manufactured using optical MEMS technology and integrates a micro-light reflector with a MEMS driver.

[0068] A micro-vibration mirror (MEMS micro-vibration mirror) is an optical micro-electromechanical device based on Micro Electro Mechanical Systems (MEMS) technology that integrates a micro-mirror and a micro-actuator. Its movement modes include two mechanical movements: translation and torsion. For a torsional micro-vibration mirror, beam manipulation is achieved through the precise movement of the micro-mirror to adjust the spatial distribution of the incident light beam. When its optical deflection angle is large (reaching more than 10°), its main function is to achieve laser pointing deflection, graphical scanning, and image scanning. It can be called a "MEMS scanning mirror" to distinguish it from a torsional micro-vibration mirror with a smaller deflection angle. Due to its advantages such as small size, low power consumption, fast response speed and high scanning frequency, it is widely used in laser radar, laser projection, optical communication, biomedicine and other fields.

[0069] Among them, electrostatically driven micro-vibration mirrors are the most common in practical applications due to their simple structure, mature technology, and low power consumption. Electrostatically driven micro-vibration mirrors typically consist of a fixed electrode and a movable mirror. The movable mirror typically consists of a movable electrode, a torsion beam, and a reflector connected in sequence. The movable electrode is placed near the fixed electrode. The basic principle is to apply a voltage between the fixed and movable electrodes, using the electrostatic interaction force to drive the deflection of the entire reflector to achieve optical control.

[0070] However, conventional electrostatically driven micro-vibration mirrors have the problems of low driving force and small scanning angle. To solve this problem, existing electrostatically driven micro-vibration mirrors are usually configured as a two-layer vertical comb-tooth structure, that is, the fixed electrode is offset in the vertical direction to one side of the movable electrode, such as the upper side or the lower side, thereby increasing the deflection angle of the reflector, that is, increasing the scanning angle of the micro-vibration mirror. However, the two-layer vertical comb-tooth drive structure still has limited effect on the deflection angle of the reflector. Moreover, when the reflector is driven, the movable electrode connected to it is only subjected to a downward or upward electrostatic force. The resultant electrostatic force on the reflector and the torsion beam is not equal to zero, causing the torsion axis and the reflector to deviate from the equilibrium position, resulting in unbalanced motion, thereby interfering with the scanning process of the micro-vibration mirror and affecting the reliability of the micro-vibration mirror.

[0071] Based on this, refer to Figures 1 to 21, this embodiment provides an electrostatically driven micro-vibration mirror, comprising: a first functional structure layer 1, a second functional structure layer 2 and a third functional structure layer 3 stacked in sequence and insulated; wherein the first functional structure layer 1 comprises a first driving structure 11 and a second driving structure 12, the first driving structure 11 and the second driving structure 12 are spaced and insulated in the first direction, and form a first accommodating space 13; the second functional structure layer 2 comprises a torsional reflector assembly, and the torsional reflector assembly is suspended above the first accommodating space 13; the torsional reflector assembly comprises a first transmission structure 21, a reflector structure 22 and a second transmission structure 23 connected in sequence in the second direction, the second direction forms a preset angle with the first direction, the reflective surface of the reflector structure 22 deviates from the first functional structure layer 1, the first transmission structure 21 and the second transmission structure 23 are collinearly arranged and the straight line on which they are located passes through the center of the reflector structure 22; the first driving structure 11 and the second driving structure 12 are relative to the center of the reflector structure 22 The center is symmetrically arranged about the projection point on the plane of the first functional structure layer 1; the third functional structure layer 3 includes a third driving structure 31 and a fourth driving structure 32 which are spaced and insulated. The third driving structure 31 and the first driving structure 11 are arranged correspondingly up and down, and the fourth driving structure 32 and the second driving structure 12 are arranged correspondingly up and down. A second accommodating space 33 is formed between the third driving structure 31 and the fourth driving structure 32, and the second accommodating space 33 corresponds to the first accommodating space 13 up and down to provide a deflection space for the torsional reflector assembly; the first driving structure 11 and the fourth driving structure 32 are suitable for generating an electrostatic adsorption force on the torsional reflector assembly under the action of an equal external non-zero voltage, so as to deflect the torsional reflector assembly along a first torsional direction; or, the second driving structure 12 and the third driving structure 31 are suitable for generating an electrostatic adsorption force on the torsional reflector assembly under the action of an equal external non-zero voltage, so as to deflect the torsional reflector assembly along a second torsional direction, and the first torsional direction and the second torsional direction are opposite.

[0072] Specifically, the first functional structure layer 1, the second functional structure layer 2 and the third functional structure layer 3 are stacked in sequence in the vertical direction, and the surfaces connected to each other in the stacking direction are all set to be insulated contact, for example, an insulating layer is set on the contact surface. Figures 2 to 5, among the three functional structure layers, the first functional structure layer 1 is arranged at the bottom, and the layer includes a first drive structure 11 and a second drive structure 12 that are spaced apart along the first direction. The first direction of this embodiment can be understood as the front-back direction on the horizontal plane, and the second direction can be understood as the left-right direction on the horizontal plane. Exemplarily, the first drive structure 11 and the second drive structure 12 can be flat plate structures or comb tooth structures. The first drive structure 11 and the second drive structure 12 are suitable for being electrically connected to an external power supply to serve as fixed structures for receiving external applied voltage, and the relatively close side of the first drive structure 11 and the second drive structure 12 serves as the driving end of the electrostatic drive to achieve mutual force with the torsional reflector assembly, and the relatively distant side can serve as the fixed end to achieve installation and fixation. The spacing area between the first drive structure 11 and the second drive structure 12 forms a first accommodating space 13. In this embodiment, the middle area of the spacing area in the second direction forms the first accommodating space 13 in the form of a circular groove or a circular hole. Of course, it can also be a square or other shape, as long as it is compatible with the shape of the reflector structure 22. Reference Figures 1 to 5The second functional structure layer 2 is arranged above the first functional structure layer 1. The torsional reflector assembly of the second functional structure layer 2 includes a first transmission structure 21, a reflector structure 22, and a second transmission structure 23 arranged in sequence along the second direction. The first transmission structure 21 and the second transmission structure 23 are arranged as long strip structures extending along the second direction and having a rotation center axis. In this embodiment, they are preferably rod-shaped structures with comb teeth. The reflector structure 22 is arranged as a disk-shaped structure, which can be any of a variety of shapes such as round and square. In this embodiment, a disk-shaped structure is preferred. In the initial state without force, the circular reflective surface faces upward, and the first transmission structure 21 and the second transmission structure 23 are arranged collinearly on the side wall of the reflector structure 22. And it is located in the radial direction of the reflector structure 22, so as to drive the middle reflector structure 22 to deflect symmetrically and stably when subjected to force. The first transmission structure 21 and the second transmission structure 23 are suitable for generating an electrostatic force between the first drive structure 11 or the second drive structure 12. For example, when there is an external non-zero voltage on the first drive structure 11 or the second drive structure 12, a downward electrostatic adsorption force can be generated on the first transmission structure 21 and the second transmission structure 23 close to one of the drive structures in the first direction, so that the first transmission structure 21 and the second transmission structure 23 simultaneously drive the reflector structure 22 to twist toward that side to achieve deflection scanning. The external non-zero voltage here can be a positive voltage or a negative voltage. In this embodiment, the first driving structure 11 and the second driving structure 12 are first arranged on the same horizontal plane, and then the center of the reflector structure 22 is projected onto the plane where the first functional structure layer 1 is located. Then, the first driving structure 11 and the second driving structure 12 are symmetrical about this projection point. In this way, when the external voltage is the same, in the first direction, the electrostatic adsorption torque generated by the first driving structure 11 on the torsional reflector assembly and the electrostatic adsorption torque generated by the second driving structure 12 on the torsional reflector assembly are equal, that is, the degree of deflection of the torsional reflector assembly toward both sides is the same, which helps to maintain the torsional reflector assembly in a balanced position, thereby achieving stable scanning.

[0073] On this basis, reference Figure 1 、 Figures 3 to 5, a third functional structure layer 3 is arranged above the second functional structure layer 2 corresponding to the first functional structure layer 1, and the structural arrangement of the third functional structure layer 3 is the same as that of the first functional structure layer 1, including position, size, distance, etc. Specifically, the third driving structure 31 corresponds to the first driving structure 11 up and down, the fourth driving structure 32 corresponds to the second driving structure 12 up and down, and the second accommodating space 33 corresponds to the first accommodating space 13 up and down, and together constitute a space for twisting the torsional reflector assembly. In this embodiment, when driving the torsional reflector assembly of the second functional structure layer, an external non-zero voltage is applied to a group of driving structures that can connect the upper and lower oblique connections of the reflector assembly, such as an external non-zero voltage is simultaneously applied to the first driving structure 11 below and the fourth driving structure 32 above, so that the torsional reflector assembly generates a first torsional direction, such as in Figure 4 or the second drive structure 12 below and the third drive structure 31 above, so that the torsional reflector assembly produces a second torsion direction, such as Figure 5 Clockwise twisting under the viewing angle. Each set of such driving structures can apply a set of electrostatic forces of opposite directions and equal magnitudes to the torsion reflector assembly, so that the resultant electrostatic force on the torsion reflector assembly is equal to zero, thereby preventing the rotation axis of the torsion reflector assembly from deviating from the equilibrium position, that is, avoiding the interference caused by unbalanced movement, and ensuring the scanning stability of the micro-vibration mirror; and the driving structure of the first functional structure layer and the driving structure of the third functional structure layer of the present application are respectively distributed on both sides of the plane where the torsion reflector assembly is located in the vertical direction. Compared with the conventional solution of unilaterally offsetting the driving structure in the vertical direction, the electrostatic torque on the torsion reflector assembly of the present application is twice that of the conventional solution.

[0074] In summary, the electrostatically driven micro-vibration mirror in this embodiment adopts a "sandwich" type structural design, in which the first functional structure layer 1 and the third functional structure layer 3 with a fixed driving structure are respectively arranged on the upper and lower sides of the second functional structure layer 2 with a movable torsional reflector assembly, which greatly increases the driving force of the micro-vibration mirror, thereby increasing the scanning angle of the micro-vibration mirror; more importantly, since the driving structures arranged on the upper and lower sides are symmetrically distributed on both sides of the plane where the torsional reflector assembly is located, the electrostatic forces acting on the torsional reflector assembly or the reflector structure 22 are equal in magnitude and opposite in direction, which avoids the torsion axis from deviating from the equilibrium position, thereby avoiding the interference caused by unbalanced motion. That is, the electrostatically driven micro-vibration mirror in this embodiment can not only avoid the interference caused by unbalanced motion, ensure the scanning stability of the micro-vibration mirror, but also provide a larger scanning angle.

[0075] It should be known that if the driving structure between the first functional structure layer 1, the third functional structure layer 3 and the second functional structure layer 2 is set as a flat plate structure, space should be reserved for twisting between the upper and lower parts. If it is set as a comb tooth structure, the upper and lower fixed comb teeth and the middle movable comb teeth should be staggered.

[0076] Furthermore, in this embodiment, the first drive structure 11, the second drive structure 12, the third drive structure 31, the fourth drive structure 32, the first transmission structure 21 and the second transmission structure 23 are all configured as comb-tooth structures, and each comb-tooth structure includes a plurality of comb teeth arranged at intervals along the second direction. Specifically, Figure 1 and Figure 2 As shown, the first transmission structure 21 includes a first torsion beam 211 and a first movable comb tooth structure 212 and a third movable comb tooth structure 213 respectively arranged on the outer periphery of the first torsion beam 211 in the first direction, and the second transmission structure 23 includes a second torsion beam 231 and a second movable comb tooth structure 232 and a fourth movable comb tooth structure 233 respectively arranged on the outer periphery of the second torsion beam 231 in the first direction; in the first direction, the first movable comb tooth structure 212 and the second movable comb tooth structure 232 are toward the side of the first driving structure 11 and the third driving structure 31, and the third movable comb tooth structure 213 and the fourth movable comb tooth structure 233 are toward the side of the second driving structure 12 and the fourth driving structure 32. The first transmission structure 21 and the second transmission structure 23 are both configured to have multiple comb teeth on both sides of the torsion beam along the first direction, and the reflector structure 22 has torsion beams on both sides along the second direction. The movable comb tooth structure on the torsion beam is suitable for generating electrostatic force with the fixed comb tooth structure above or below. Compared with the flat plate structure, the comb tooth structures can generate a greater driving force under the same area, and the driving force is more stable.

[0077] like Figure 2As shown, the above-mentioned first driving structure 11 includes a first fixed comb tooth structure 111 and a second fixed comb tooth structure 112, the first fixed comb tooth structure 111 and the first movable comb tooth structure 212 are staggered up and down, and the second fixed comb tooth structure 112 and the second movable comb tooth structure 232 are staggered up and down; the second driving structure 12 includes a third fixed comb tooth structure 121 and a fourth fixed comb tooth structure 122, the third fixed comb tooth structure 121 and the third movable comb tooth structure 213 are staggered up and down, and the fourth fixed comb tooth structure 122 and the fourth movable comb tooth structure 233 are staggered up and down. Correspondingly, the third driving structure 31 includes a fifth fixed comb tooth structure 311 and a sixth fixed comb tooth structure 312, the fifth fixed comb tooth structure 311 and the first fixed comb tooth structure 111 are arranged in correspondence with each other up and down, and the sixth fixed comb tooth structure 312 and the second fixed comb tooth structure 112 are arranged in correspondence with each other up and down; the fourth driving structure 32 includes a seventh fixed comb tooth structure 321 and an eighth fixed comb tooth structure 322, the seventh fixed comb tooth structure 321 and the third fixed comb tooth structure 121 are arranged in correspondence with each other up and down, and the eighth fixed comb tooth structure 322 and the fourth fixed comb tooth structure 122 are arranged in correspondence with each other up and down.

[0078] The above-mentioned staggered arrangement means that, when viewed from above, any comb tooth in the movable comb tooth structure is located in the gap between two adjacent comb teeth in the fixed comb tooth structure. For example, any movable comb tooth in the first movable comb tooth structure 212 is located between two adjacent fixed comb teeth in the first fixed comb tooth structure 111 that are closest to the movable comb tooth. This is equivalent to being located between two adjacent fixed comb teeth in the fifth fixed comb tooth structure in the third drive structure 31 corresponding to the first fixed comb tooth structure 111, so that the movable comb teeth in the middle layer have room for twisting when twisting occurs. In this application, the first drive structure 11 and the third drive structure 31 located on the same side of the torsional reflector assembly in the first direction correspond to the first movable comb tooth structure 212 and the second movable comb tooth structure 232, which are configured as two-part fixed comb tooth structures in the second direction. Similarly, the second drive structure 12 and the fourth drive structure 32 located on the other side of the torsional reflector assembly in the first direction are also configured as two-part fixed comb teeth.

[0079] As an optional embodiment, in this embodiment, the first fixed comb tooth structure 111 and the second fixed comb tooth structure 112 are connected, the third fixed comb tooth structure 121 and the fourth fixed comb tooth structure 122 are connected; the fifth fixed comb tooth structure 311 and the sixth fixed comb tooth structure 312 are connected, and the seventh fixed comb tooth structure 321 and the eighth fixed comb tooth structure 322 are connected.

[0080] That is, four fixed comb-tooth structures distributed in a matrix are formed in the first functional structure layer 1. Similarly, four fixed comb-tooth structures distributed in a matrix are also formed in the third functional structure layer 3. These structures are formed by partially removing a silicon wafer, and the above-mentioned two-to-two connections are achieved by retaining the two parts of the first substrate 14. The first fixed comb-tooth structure 111 and the second fixed comb-tooth structure 112 require the same external voltage when driving. When the two are connected as an integrated structure, the overall electrical drive can be achieved by applying voltage to one of them. That is, when driving, one of the two fixed comb-tooth structures in each driving structure can be selected for lead electrical connection, thereby improving the flexibility and fault tolerance of applying external voltage. Even if one of the lead connection points fails, it will not affect the micro-vibration mirror drive. For the selection of the driving structure, it is sufficient to select a group (two) of driving structures located on different sides of the torsional reflector assembly in the first horizontal direction, and at the same time, this group of driving structures must also be located on different sides of the torsional reflector assembly in the vertical direction.

[0081] Of course, it is not ruled out that the first fixed comb tooth structure 111 and the second fixed comb tooth structure 112 are insulated, the third fixed comb tooth structure 121 and the fourth fixed comb tooth structure 122 are insulated, the fifth fixed comb tooth structure 311 and the sixth fixed comb tooth structure 312 are insulated, and the seventh fixed comb tooth structure 321 and the eighth fixed comb tooth structure 322 are insulated.

[0082] That is, four fixed comb-tooth structures distributed in a matrix and insulated from each other are formed in the first functional structure layer 1. Similarly, four fixed comb-tooth structures distributed in a matrix and insulated from each other are also formed in the third functional structure layer 3. In this way, when the two fixed comb-tooth structures in each driving structure are driven, two leads need to be simultaneously connected to the same external voltage to ensure that the electrostatic adsorption force generated on this driving structure is consistent.

[0083] For example, if you want to make the torsional reflector assembly produce a first torsional deflection, that is, reference Figure 4 In the counterclockwise direction shown, an external non-zero voltage can be applied to the first drive structure 11 and the fourth drive structure 32 at the same time, that is, an equal external non-zero voltage is applied to the first fixed comb structure 111 and the second fixed comb structure 112 and the seventh fixed comb structure 321 and the eighth fixed comb structure 322 at the same time. At this time, the voltage on the other fixed comb structures is zero, and the middle movable comb structure is grounded. In this way, the first drive structure 11 applies an equal external non-zero voltage to the torsional reflector assembly. Figure 4 The left side of the viewing angle generates a downward electrostatic attraction force F1, and the fourth driving structure 32 generates an upward electrostatic adsorption force F2 on the right side of the torsional reflector assembly, so that the torsional reflector assembly deflects along the first torsional direction, that is, counterclockwise.

[0084] For example, if you want to make the torsional reflector assembly produce a second torsional deflection, that is, reference Figure 5 As shown in the clockwise deflection, the same non-zero voltage can be applied to the second drive structure 12 and the third drive structure 31 at the same time, that is, the same external non-zero voltage is applied to the third fixed comb structure 121 and the fourth fixed comb structure 122 and the fifth fixed comb structure 311 and the sixth fixed comb structure 312 at the same time. At this time, the voltage on the other fixed comb structures is zero, and the middle movable comb structure is grounded. In this way, the third fixed comb structure 121 and the fourth fixed comb structure 122 in the second drive structure 12 have an effect on the torsional reflector assembly. Figure 5 A downward electrostatic attraction force F4 is generated on the right side of the illustrated perspective, and the fifth fixed comb structure 311 and the sixth fixed comb structure 312 in the third drive structure generate an upward electrostatic adsorption force F3 on the left side of the torsional reflector assembly, causing the torsional reflector assembly to deflect in the second torsional direction, i.e., clockwise. Of course, in actual scanning, it is possible to choose to apply the same external non-zero voltage only to the first drive structure 11 and the fourth drive structure 32, or to apply the same external non-zero voltage only to the second drive structure 12 and the third drive structure 31. It is understandable that when the external non-zero voltage is applied only to the first drive structure 11 and the fourth drive structure 32, or only to the first drive structure 11 and the fourth drive structure 32, after the torsional reflector assembly deflects to the limit, the external voltage is removed and the torsional reflector assembly rebounds under the action of the stress. Alternatively, the same external non-zero voltage can be applied sequentially to the first drive structure 11 and the fourth drive structure 32, and the second drive structure 12 and the third drive structure 31 within a cycle.

[0085] In one embodiment, Figures 1 to 3 As shown, the reflector structure 22 includes a main structure 221 and a reflective layer 222 . The main structure 221 is integrally formed with the first transmission structure 21 and the second transmission structure 23 . The reflective layer 222 is arranged on a side surface of the main structure 221 that is opposite to the first functional structure layer 1 .

[0086] For example, a silicon wafer can be partially etched and removed to form an integrally connected main structure 221, first transmission structure 21, and second transmission structure 23, thereby forming a highly consistent torsional reflector assembly. A reflective layer 222 is disposed on the side of the main structure 221 facing away from the first functional structure layer 1 to better deflect external light and enable optical manipulation such as graphical scanning and image scanning. In this embodiment, the reflective layer 222 is made of a metal material, such as 100nm thick gold, which exhibits excellent reflective properties.

[0087] Furthermore, on the side of the main structure 221 facing away from the reflective layer 222 , the surface portion of the main structure 221 is recessed inward to form a groove 2211 and a rib 2212 .

[0088] refer to Figure 2 In this embodiment, the silicon wafer has a thickness of 100 μm. Then, on the back side of the silicon wafer, that is, on the side facing the first functional structure layer 1, partial area and partial depth etching is performed, and the etching depth is 30 μm to 40 μm. At this depth, the etched area forms a weight-reducing groove 2211, which reduces the weight of the reflector structure 22 and increases the scanning frequency; the retained ribs 2212 help to increase the rigidity of the reflector structure 22 and prevent the reflector structure 22 from deforming too much, so that the reflector structure 22 can achieve stable deflection driven by the first torsion beam 211 and the second torsion beam 231.

[0089] In one embodiment, the first functional structure layer 1 further includes a first substrate 14 and a first insulating layer 15, the first insulating layer 15 is arranged on one side surface of the first substrate 14, the first driving structure 11 and the second driving structure 12 are integrally formed on the side of the first substrate 14 away from the first insulating layer 15, and the first accommodating space 13 passes through the first substrate 14; the second functional structure layer 2 further includes a second substrate 24 and a second insulating layer 25, the second insulating layer 25 is arranged on one side surface of the second substrate 24 close to the first functional structure layer 1 to be connected to the first substrate 14, and the two ends of the torsional reflector assembly are connected to the second substrate. The third functional structure layer 3 further comprises a third base body 34 and a third insulating layer 35. The third insulating layer 35 is arranged on a side surface of the third base body 34 close to the second functional structure layer 2 to be connected to the second base body 24. The third driving structure 31 and the fourth driving structure 32 are integrally formed on the third base body 34 and are suspended above the first driving structure 11 and the second driving structure 12. The second accommodating space 33 passes through the third base body 34 and the third insulating layer 35 to form a torsional space of the torsional reflector assembly with the first accommodating space 13.

[0090] refer to Figure 3In this embodiment, the first substrate 14 is used to achieve fixed installation of the first functional structure layer 1. A first insulating layer 15 is provided on one side surface thereof, suitable for achieving insulation between the first functional structure layer 1 and the second functional structure layer 2. The second functional structure layer 2 includes a second substrate 24 and a second insulating layer 25 provided on one side surface of the second substrate 24. The second functional structure layer 2 is fixed to the first functional structure layer 1 with the second insulating layer 25 facing the first substrate 14, that is, the first substrate 14 and the second substrate 24 are insulated by the second insulating layer 25. Similarly, the third insulating layer 35 of the third functional structure layer 3 is provided between the third substrate 34 and the second substrate 24 to achieve insulation. It should be noted that when forming the torsional reflector assembly on the second substrate 24 and the third drive structure 31 and the fourth drive structure 32 on the third substrate 34, the corresponding insulating layer under the etched area must be removed to release the movable structure. The first insulating layer 15 in the first functional structure layer 1 can be left unchanged to reduce the number of processing steps. In this embodiment, the first base 14 , the second base 24 and the third base 34 are all made of silicon layers, and the first insulating layer 15 , the second insulating layer 25 and the third insulating layer 35 are all made of silicon oxide layers with a thickness of 1 μm.

[0091] Specifically in this embodiment, the first functional structure layer 1 may include a first drive structure 11 and a second drive structure 12, which are integrally formed with different portions of the first base 14. For example, the first drive structure 11, the second drive structure 12, and the first base 14 connected to the two drive structures may be formed by etching a silicon wafer, and the first base 14 may be formed into a plurality of matching sub-portions according to the specific configuration of the first drive structure 11 and the second drive structure 12. For example, the first base 14 is configured as two parts relatively separated along the first direction according to the relatively spaced first drive structure 11 and the second drive structure 12. At this time, the first fixed comb tooth structure 111 and the second fixed comb tooth structure 112 are connected to form an integral first drive structure 11, and the third fixed comb tooth structure 121 and the fourth fixed comb tooth structure 122 are connected to form an integral second drive structure 12; further, the first drive structure 11 can also be configured as the first fixed comb tooth structure 111 and the second fixed comb tooth structure 112 spaced along the second direction, and the second drive structure 12 is configured as the third fixed comb tooth structure 121 and the fourth fixed comb tooth structure 122 spaced along the second direction, then the first base 14 is divided into four sub-parts corresponding to the four fixed comb tooth structures, reference Figure 2The first base 14 includes a first sub-base 14a connected to the first fixed comb-tooth structure 111, a second sub-base 14b connected to the second fixed comb-tooth structure 112, a third sub-base 14c connected to the third fixed comb-tooth structure 121, and a fourth sub-base 14d connected to the fourth fixed comb-tooth structure 122. In this embodiment, the first sub-base 14a and the second sub-base 14b are essentially connected to form a whole and connected to the first driving structure 11; the third sub-base 14c and the fourth sub-base 14d are connected to form a whole and connected to the second driving structure 12. Figure 2 The four sub-matrices shown are isolated from each other only for ease of description.

[0092] Similarly, the third driving structure 31 and the fourth driving structure 32 are integrally arranged with different parts of the third base 34 in the third functional structure layer 3. On the basis that the third driving structure 31 corresponds to the first driving structure 11 in upper and lower positions, and the fourth driving structure 32 corresponds to the second driving structure 12 in upper and lower positions, the third base 34 can be arranged to correspond to the first base 14 in upper and lower positions, that is, the third base 34 is also formed into a plurality of matching sub-parts according to the specific arrangement of the third driving structure 31 and the fourth driving structure 32. For example, the third base 34 is arranged into two parts that are relatively separated along the first direction according to the relatively spaced third driving structure 31 and the fourth driving structure 32; or referring to Figure 1 , the third driving structure 31 is configured as a fifth fixed comb tooth structure 311 and a sixth fixed comb tooth structure 312 spaced apart along the second direction, and the fourth driving structure 32 is configured as a seventh fixed comb tooth structure 321 and an eighth fixed comb tooth structure 322 spaced apart along the second direction, then the third base 34 is divided into four sub-parts corresponding to the four fixed comb tooth structures, specifically, the third base 34 includes a fifth sub-base 34a connected to the fifth fixed comb tooth structure 311, a sixth sub-base 34b connected to the sixth fixed comb tooth structure 312, a seventh sub-base 34c connected to the seventh fixed comb tooth structure 321, and an eighth sub-base 34d connected to the eighth fixed comb tooth structure 322. In essence, the fifth sub-base 34a and the sixth sub-base 34b in this embodiment are connected as a whole and connected to the third driving structure 31; the seventh sub-base 34c and the eighth sub-base 34d are connected as a whole and connected to the fourth driving structure 32. Figure 1 The four sub-matrices shown are isolated from each other only for ease of description.

[0093] For the second functional structural layer 2, the second base 24 may include a first anchor region connected to the end of the first torsion beam 211 away from the reflector structure 22, and a second anchor region connected to the end of the second torsion beam 231 away from the reflector structure 22 (the first anchor region and the second anchor region may refer to Figure 3The first and second anchor regions are used to support the suspended torsional reflector assembly. In this embodiment, the first anchor region, the first transmission structure 21, the main structure 221 of the reflector structure 22, the second transmission structure 23, and the second anchor region are integrally formed by etching a silicon wafer.

[0094] Based on the above scheme, the first functional structure layer 1 also includes a first electrode 16, which is arranged on the first substrate 14, and the second substrate 24 exposes the first electrode 16, and the first electrode 16 is suitable for connecting an external power supply and the first substrate 14; the second functional structure layer 2 also includes a second electrode 26, which is arranged on the second substrate 24, and the third substrate 34 exposes the second electrode 26, and the second electrode 26 is suitable for grounding the torsional reflector assembly; the third functional structure layer 3 also includes a third electrode 36, which is arranged on the third substrate 34, and the third electrode 36 is suitable for connecting an external power supply and the third substrate 34.

[0095] The first and third electrodes here are the lead electrical connection points corresponding to each of the above-mentioned fixed comb-tooth structures. The first electrode 16 is set according to the specific structure of the first substrate 14. For example, if the first substrate 14 is divided into two sub-substrates, then one first electrode 16 is set on each sub-substrate; if the first substrate 14 is set as four sub-substrates, then four first electrodes 16 are set accordingly, so that each fixed comb-tooth structure of the first functional structure layer 1 has a separate corresponding first electrode 16. Similarly, the number of third electrodes 36 is also set according to the number of sub-substrates of the third substrate 34. For the second substrate 24, one second electrode 26 or two second electrodes 26 can be set, as long as grounding is achieved. It should be noted that because the three functional structure layers are stacked, the upper structure should expose the electrodes of the lower structure to facilitate electrical connection with external structures. In this embodiment, the edges of the first functional structure layer 1, the second functional structure layer 2, and the third functional structure layer 3 are stepped to expose the corresponding electrodes of the lower layer. The first electrode 16 , the second electrode 26 and the third electrode 36 may be made of a 100 nm thick gold layer, which is highly inert and not easily oxidized.

[0096] In one embodiment, the electrostatically driven micro-vibration mirror further includes a substrate layer 4, disposed on the side of the first functional structure layer 1 facing away from the second functional structure layer 2. The first functional structure layer 1, the second functional structure layer 2, and the third functional structure layer 3 are stacked sequentially on the substrate layer 4 to provide support for these three functional structure layers. In this embodiment, the substrate layer 4 is constructed from a 400 μm thick silicon wafer, which is thicker than the first functional structure layer 1, the second functional structure layer 2, and the third functional structure layer 3.

[0097] refer to Figures 6 to 21 This embodiment also provides a method for preparing an electrostatically driven micro-vibration mirror, which is used to prepare the above-mentioned electrostatically driven micro-vibration mirror. Figure 6 Schematic diagram of the preparation method, the preparation method comprises:

[0098] Step S801 : forming a first functional structure layer 1 , the first functional structure layer 1 including a first driving structure 11 and a second driving structure 12 , the first driving structure 11 and the second driving structure 12 are spaced and insulated from each other in a first direction, and form a first accommodating space 13 .

[0099] For example, a first functional structure layer 1 having a first driving structure 11 and a second driving structure 12 may be formed by etching a silicon wafer, and after etching, a recessed space in the middle region of the silicon wafer is used as the first accommodating space 13 .

[0100] Step S802: The second functional structure layer 2 is arranged on one side of the first functional structure layer 1. The second functional structure layer 2 includes a torsional reflector assembly, which is suspended above the first accommodating space 13. The torsional reflector assembly includes a first transmission structure 21, a reflector structure 22, and a second transmission structure 23 connected in sequence in a second direction. The second direction forms a preset angle with the first direction. The reflective surface of the reflector structure 22 is away from the first functional structure layer 1. The first transmission structure 21 and the second transmission structure 23 are collinearly arranged and the straight line on which they are located passes through the center of the reflector structure 22. The first drive structure 11 and the second drive structure 12 are symmetrically arranged relative to the projection point of the center of the reflector structure 22 on the plane of the first functional structure layer 1.

[0101] For example, the back structure can be etched on one side surface of another silicon wafer to form the back side of the second functional structure layer 2, and then the silicon wafer is bonded to the first functional structure layer 1 with the back side facing the first functional structure layer 1, and then the front side of the silicon wafer is etched to form the corresponding front structure, and finally a torsional reflector assembly is formed. The relevant structural settings are as described above and will not be repeated here.

[0102] In step S803, the third functional structure layer 3 is arranged on the side of the second functional structure layer 2 away from the first functional structure layer 1. The third functional structure layer 3 includes a third driving structure 31 and a fourth driving structure 32 that are spaced and insulated. The third driving structure 31 and the first driving structure 11 are arranged in correspondence with each other up and down, and the fourth driving structure 32 and the second driving structure 12 are arranged in correspondence with each other up and down; a second accommodating space 33 is formed between the third driving structure 31 and the fourth driving structure 32, and the second accommodating space 33 corresponds to the first accommodating space 13 up and down to provide a deflection space for the torsional reflector assembly.

[0103] Illustratively, a third functional structure layer 3 having a third driving structure 31 and a fourth driving structure 32 is formed by etching another silicon wafer. After the third driving structure 31 and the first driving structure 11 are etched, the recessed space in the middle area of the silicon wafer is used as the second accommodating space 33. The second accommodating space 33 corresponds to the first solute space in the upper and lower directions.

[0104] In this embodiment's method for fabricating an electrostatically driven micro-vibration mirror, each functional structure layer is formed by etching a silicon wafer into the desired functional structure. The three functional structure layers are stacked and insulated from each other. By flexibly energizing the drive structures in the upper and lower layers and configuring the deflection drive for the torsional reflector assembly in the middle layer, this effectively increases the scanning angle of the middle torsional reflector assembly while preventing any imbalance in the torsional reflector assembly, ensuring scanning stability and ultimately improving the scanning performance of the electrostatically driven micro-vibration mirror.

[0105] Specifically, before the step S801 of forming the first functional structure layer 1, the process further includes: providing a substrate layer 4. The substrate layer 4 can be a separate silicon substrate or an SOI substrate, i.e., a silicon-on-insulator, which is a silicon on an insulating substrate, specifically, a buried oxide layer is introduced between the top silicon layer and the back substrate. Figure 7 As shown, in this embodiment, an SOI substrate is selected, and the two sides of the first insulating layer 15 formed by silicon oxide are respectively a silicon device layer and a silicon support layer. The silicon device layer is about 100 μm thick and is used to form the first functional structure layer 1; the silicon oxide of the first insulating layer 15 is about 1 μm thick; the silicon support layer is used as the substrate layer 4 and is about 400 μm thick.

[0106] refer to Figures 7 to 10 In this embodiment, the step S801 of forming the first functional structure layer 1 specifically includes:

[0107] Step S8011 , forming a first insulating layer 15 on one side surface of the substrate layer 4 , and forming an initial first base 100 on the first insulating layer 15 .

[0108] refer to Figure 7 The above-mentioned SOI substrate can be directly used to form the substrate layer 4, the first insulating layer 15 and the initial first base 100.

[0109] Step S8012 , pre-processing the substrate layer 4 , the first insulating layer 15 and the initial first base 100 .

[0110] That is, before etching to form the first functional structure layer 1 , the SOI substrate needs to be pretreated. In this embodiment, a diluted buffered hydrofluoric acid solution is used to remove the low-density native oxide layer on the surface of the initial first substrate 100 .

[0111] Step S8013 , forming a first electrode 16 on the initial first substrate 100 .

[0112] like Figure 8 As shown, according to design requirements, a photoresist is used as a mask at the edge of the upper surface of the initial first substrate 100, and then gold is sputtered to a thickness of 100 nm, and then the resist is removed to form the first electrode 16.

[0113] In step S8014 , a portion of the initial first substrate 100 is removed by etching to form the first substrate 14 , the first accommodating space 13 , the first driving structure 11 and the second driving structure 12 . The first accommodating space 13 passes through the initial first substrate 100 .

[0114] like Figure 9 As shown, first, a photoresist is placed on the upper surface of the initial first substrate 100 as a mask, and the central area of the initial first substrate 100 is dry-etched by about 100 microns to remove the entire thickness of the silicon layer in this area to form the first accommodation space 13. After that, the first insulating layer 15 below this area is further etched to ensure absolute insulation below the formed first accommodation space 13, and then the photoresist is removed. Then, as shown in FIG. Figure 10 As shown, photoresist is sprayed on the upper surface of the initial first substrate 100 on both sides of the first accommodating space 13 as a mask for etching, and silicon with a thickness of about 60 μm is dry-etched to form a first driving structure 11 and a second driving structure 12 of a comb-tooth structure. At the same time, other silicon layers on the edge form the first substrate 14. Finally, the photoresist is removed to form a first functional structure layer 1.

[0115] refer to Figures 11 to 16 In this embodiment, the step S802 of disposing the second functional structure layer 2 on one side of the first functional structure layer 1 specifically includes the following steps:

[0116] Step S8021: providing an initial second substrate 200.

[0117] For example, the initial second substrate 200 may be made of the same silicon wafer as the initial first substrate 100 .

[0118] Step S8022 , pre-processing the initial second substrate 200 .

[0119] Specifically, a diluted buffered hydrofluoric acid solution may be used for pretreatment to remove the native oxide layer with low density on the surface of the initial second substrate 200 .

[0120] Step S8023 : forming a second insulating layer 25 on one side surface of the initial second substrate 200 .

[0121] refer to Figure 11A second insulating layer 25 with a higher density can be formed by growing a 1 μm thick silicon oxide layer on one side surface of the initial second substrate 200 using a thermal oxidation method.

[0122] In step S8024 , etching is performed on the side of the initial second substrate 200 having the second insulating layer 25 to form the main structure 221 of the reflector structure 22 .

[0123] like Figure 12 As shown, a photoresist is coated on the upper surface of the second insulating layer 25 as a mask, and then the first insulating layer 15 in the area not coated with the photoresist is removed by dry etching; thereafter, the silicon material of the initial first substrate 100 is etched using the remaining silicon oxide as a hard mask, with an etching depth of 30μm to 40μm, thereby forming a groove 2211 and a rib 2212 on the back side of the main structure 221.

[0124] In step S8025 , the initial second substrate 200 formed with the main structure 221 is turned over so that the second insulating layer 25 is fixed on the first substrate 14 toward the first functional structure layer 1 , and the initial second substrate 200 covers the first electrode 16 .

[0125] like Figure 13 As shown, the initial second substrate 200 is bonded and fixed on one side of the groove 2211 and the rib 2212 to the first substrate 14, and then the initial second substrate 200 is thinned to about 60μm from one side of the upper surface so that the subsequently formed torsional reflector assembly can maintain a suitable deadweight, thereby facilitating efficient and stable torsional scanning.

[0126] Step S8026 , forming a reflective layer 222 and a second electrode 26 on a side of the initial second substrate 200 away from the first functional structure layer 1 , wherein the reflective layer 222 is disposed corresponding to the main structure 221 .

[0127] like Figure 14 As shown, a photoresist is coated on the upper surface of the initial second substrate 200 as a mask, and a gold layer with a thickness of about 100 nm is formed by sputtering. The photoresist is then removed, and a reflective layer 222 is formed in the main structure 221 area to regulate the incident light, and a second electrode 26 is formed in the edge area.

[0128] In step S8027 , etching is performed on the side of the initial second substrate 200 facing away from the first functional structure layer 1 to form a first transmission structure 21 and a second transmission structure 23 , so that the torsional reflector assembly is suspended and at least a portion of the first electrode 16 is exposed.

[0129] like Figure 15As shown, first, a photoresist is applied to the upper surface of the initial second substrate 200 on both sides of the main structure 221 as a mask, and then the initial second substrate 200 on both sides of the main structure 221 is dry-etched by about 60 μm to form a torsional reflector assembly. This step simultaneously removes the edge of the initial second substrate 200 to expose the first electrode 16. Figure 16 As shown, dry over-etching is performed on the areas outside the first twisted reflector to remove the second insulating layer 25 exposed in these areas, and finally the photoresist is removed to form the second functional structure layer 2.

[0130] refer to Figures 17 to 21 In this embodiment, the step S803 of disposing the third functional structure layer 3 on the side of the second functional structure layer 2 away from the first functional structure layer 1 specifically includes the following steps:

[0131] Step S8031: providing an initial third substrate 300.

[0132] For example, the initial third substrate 300 may be made of the same silicon wafer as the initial first substrate 100 and the initial second substrate 200 .

[0133] Step S8032 , pre-treating the initial third substrate 300 .

[0134] Specifically, a diluted buffered hydrofluoric acid solution may be used for pretreatment to remove the native oxide layer on the surface of the initial third substrate 300 .

[0135] Step S8033 : forming a third insulating layer 35 on one side surface of the initial third base 300 .

[0136] For example, the third insulating layer 35 may be formed by growing silicon oxide with a thickness of 1 μm on one side surface of the initial third base 300 using a thermal oxidation method.

[0137] In step S8034 , the initial third substrate 300 formed with the third insulating layer 35 is disposed on the second functional structure layer 2 , with the third insulating layer 35 facing the second functional structure layer 2 and covering the second electrode 26 .

[0138] like Figure 17 As shown, the side of the initial third substrate 300 having the third insulating layer 35 is bonded and fixed on the second substrate 24 , and then the initial third substrate 300 is thinned from the upper surface to about 60 μm.

[0139] Step S8035 : disposing a third electrode 36 on a side of the initial third substrate 300 facing away from the second functional structure layer 2 .

[0140] like Figure 18As shown, a photoresist is coated on the upper surface of the initial third substrate 300 as a mask, and a gold layer with a thickness of about 100 nm is formed by sputtering. The photoresist is then removed, and the second electrode 26 is formed in the edge area.

[0141] In step S8035, part of the initial third base 300 and the third insulating layer 35 are etched away to form a third base 34, a second accommodating space 33, a third driving structure 31 and a fourth driving structure 32, and an exposed part of the second electrode 26. The first accommodating space 13 passes through the initial third base 300 and the third insulating layer 35.

[0142] like Figure 19 As shown, first, a photoresist is applied as a mask on the surface outside the middle area of the third initial base corresponding to the main structure 221 of the second functional structure layer 2, and the middle area of the initial third base 300 corresponding to the main structure 221 is dry-etched by about 60 μm to remove the entire thickness of the silicon layer in this part to form the second accommodating space 33. This step can be over-etched to ensure that the silicon layer is completely etched away. Figure 20 , spray photoresist on the upper surface of the initial third base 300 on both sides of the second accommodating space 33 as a mask for etching, dry-etching silicon with a thickness of about 60 μm to form the third driving structure 31 and the fourth driving structure 32 of the comb structure, while the other silicon layers on the edge form the third base 34. Then refer to Figure 21 , the exposed third insulating layer 35 is etched to expose the second electrode 26 , and finally the photoresist is removed to form the third functional structure layer 3 .

[0143] The further functional description of each of the above structures is the same as that of the above corresponding embodiments and will not be repeated here.

[0144] While the above description does not provide detailed technical details regarding patterning and etching of each layer, those skilled in the art will appreciate that various technical means can be employed to form layers, regions, and the like in desired shapes. Furthermore, those skilled in the art may devise methods that differ from those described above to form the same structure. Furthermore, while each embodiment has been described separately, this does not mean that the measures in each embodiment cannot be advantageously combined.

[0145] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. An electrostatically driven micro-vibration mirror, characterized in that: include: A first functional structure layer, a second functional structure layer, and a third functional structure layer are sequentially stacked and insulated; The first functional structure layer includes a first driving structure and a second driving structure, wherein the first driving structure and the second driving structure are spaced apart and insulated from each other in a first direction and form a first accommodating space; The second functional structure layer includes a torsion reflector assembly, which is suspended above the first accommodating space; the torsion reflector assembly includes a first transmission structure, a reflector structure, and a second transmission structure connected in sequence in a second direction, the second direction forms a preset angle with the first direction, the reflective surface of the reflector structure faces away from the first functional structure layer, and the first transmission structure and the second transmission structure are collinearly arranged, and the straight line on which they are located passes through the center of the reflector structure; The first driving structure and the second driving structure are symmetrically arranged relative to the projection point of the center of the reflector structure on the plane of the first functional structure layer; The third functional structure layer includes a third driving structure and a fourth driving structure that are spaced and insulated from each other, the third driving structure and the first driving structure are arranged in a vertically corresponding manner, and the fourth driving structure and the second driving structure are arranged in a vertically corresponding manner; A second accommodating space is formed between the third driving structure and the fourth driving structure, and the second accommodating space corresponds to the first accommodating space in upper and lower directions to provide a deflection space for the torsional reflector assembly; The first driving structure and the fourth driving structure are suitable for generating an electrostatic adsorption force on the torsional reflector assembly under the action of an equal external non-zero voltage, so that the torsional reflector assembly is deflected along a first torsional direction; or, the second driving structure and the third driving structure are suitable for generating an electrostatic adsorption force on the torsional reflector assembly under the action of an equal external non-zero voltage, so that the torsional reflector assembly is deflected along a second torsional direction, and the first torsional direction and the second torsional direction are opposite.

2. The electrostatically driven micro-vibration mirror according to claim 1, characterized in that: The first transmission structure includes a first torsion beam and a first movable comb tooth structure and a third movable comb tooth structure respectively arranged on the outer periphery of the first torsion beam in a first direction; the second transmission structure includes a second torsion beam and a second movable comb tooth structure and a fourth movable comb tooth structure respectively arranged on the outer periphery of the second torsion beam in the first direction; in the first direction, the first movable comb tooth structure and the second movable comb tooth structure face the first drive structure and the third drive structure, and the third movable comb tooth structure and the fourth movable comb tooth structure face the second drive structure and the fourth drive structure; The first driving structure includes a first fixed comb tooth structure and a second fixed comb tooth structure, the first fixed comb tooth structure and the first movable comb tooth structure are vertically staggered, and the second fixed comb tooth structure and the second movable comb tooth structure are vertically staggered; the second driving structure includes a third fixed comb tooth structure and a fourth fixed comb tooth structure, the third fixed comb tooth structure and the third movable comb tooth structure are vertically staggered, and the fourth fixed comb tooth structure and the fourth movable comb tooth structure are vertically staggered; The third driving structure includes a fifth fixed comb tooth structure and a sixth fixed comb tooth structure, the fifth fixed comb tooth structure and the first fixed comb tooth structure are arranged in correspondence with each other up and down, and the sixth fixed comb tooth structure and the second fixed comb tooth structure are arranged in correspondence with each other up and down; the fourth driving structure includes a seventh fixed comb tooth structure and an eighth fixed comb tooth structure, the seventh fixed comb tooth structure and the third fixed comb tooth structure are arranged in correspondence with each other up and down, and the eighth fixed comb tooth structure and the fourth fixed comb tooth structure are arranged in correspondence with each other up and down.

3. The electrostatically driven micro-vibration mirror according to claim 2, characterized in that: The first fixed comb tooth structure and the second fixed comb tooth structure are connected, the third fixed comb tooth structure and the fourth fixed comb tooth structure are connected; the fifth fixed comb tooth structure and the sixth fixed comb tooth structure are connected, and the seventh fixed comb tooth structure and the eighth fixed comb tooth structure are connected.

4. The electrostatically driven micro-vibration mirror according to claim 1, characterized in that: The reflector structure includes a main body structure and a reflective layer. The main body structure is integrally formed with the first transmission structure and the second transmission structure. The reflective layer is arranged on a side surface of the main body structure that is relatively away from the first functional structure layer.

5. The electrostatically driven micro-vibration mirror according to claim 4, characterized in that: On one side of the main structure facing away from the reflective layer, a surface portion of the main structure is recessed inward to form grooves and ribs.

6. The electrostatically driven micro-vibration mirror according to any one of claims 1 to 5, characterized in that: The first functional structure layer further includes a first substrate and a first insulating layer, the first insulating layer is disposed on one side surface of the first substrate, the first driving structure and the second driving structure are integrally formed on a side of the first substrate facing away from the first insulating layer, and the first accommodating space passes through the first substrate; The second functional structure layer further includes a second substrate and a second insulating layer, wherein the second insulating layer is provided on a surface of the second substrate adjacent to the first functional structure layer to be connected to the first substrate, and both ends of the torsional reflector assembly are connected to the second substrate to be suspended above the first accommodating space; The third functional structure layer also includes a third substrate and a third insulating layer. The third insulating layer is arranged on a side surface of the third substrate close to the second functional structure layer to be connected to the second substrate. The third driving structure and the fourth driving structure are integrally formed on the third substrate and suspended above the first driving structure and the second driving structure. The second accommodating space passes through the third substrate and the third insulating layer to form a torsional space of the torsional reflector assembly with the first accommodating space.

7. The electrostatically driven micro-vibration mirror according to claim 6, characterized in that: The first functional structure layer further includes a first electrode, the first electrode is disposed on the first substrate, and the second substrate exposes the first electrode, and the first electrode is suitable for connecting an external power source and the first substrate; The second functional structure layer further includes a second electrode, the second electrode is disposed on the second substrate, and the third substrate exposes the second electrode, and the second electrode is suitable for grounding the torsional reflector assembly; The third functional structure layer further includes a third electrode, which is disposed on the third substrate and is suitable for connecting an external power source and the third substrate.

8. The electrostatically driven micro-vibration mirror according to claim 1, wherein: Also includes: The substrate layer is arranged on a side of the first functional structure layer facing away from the second functional structure layer.

9. A method for preparing an electrostatically driven micro-vibration mirror, for preparing the electrostatically driven micro-vibration mirror according to any one of claims 1 to 8, characterized in that: include: forming a first functional structure layer, wherein the first functional structure layer includes a first driving structure and a second driving structure, wherein the first driving structure and the second driving structure are spaced apart and insulated from each other in a first direction and form a first accommodating space; A second functional structure layer is disposed on one side of the first functional structure layer, the second functional structure layer comprising a torsion reflector assembly, the torsion reflector assembly being suspended above the first accommodating space; the torsion reflector assembly comprising a first transmission structure, a reflector structure, and a second transmission structure connected in sequence in a second direction, the second direction forming a preset angle with the first direction, the reflective surface of the reflector structure facing away from the first functional structure layer, the first transmission structure and the second transmission structure being collinearly disposed, and the straight line on which they lie passing through the center of the reflector structure; The first driving structure and the second driving structure are symmetrically arranged relative to the projection point of the center of the reflector structure on the plane of the first functional structure layer; The third functional structure layer is arranged on a side of the second functional structure layer away from the first functional structure layer, the third functional structure layer includes a third driving structure and a fourth driving structure that are insulated and spaced apart, the third driving structure and the first driving structure are arranged in a vertically corresponding manner, and the fourth driving structure and the second driving structure are arranged in a vertically corresponding manner; A second accommodating space is formed between the third driving structure and the fourth driving structure. The second accommodating space corresponds to the first accommodating space in upper and lower directions to provide a deflection space for the torsional reflector assembly.

10. The method for preparing an electrostatically driven micro-vibration mirror according to claim 9, characterized in that: Before forming the first functional structure layer, the method further includes: providing a substrate layer; The forming of the first functional structure layer includes: forming a first insulating layer on a side surface of the substrate layer, forming an initial first base on the first insulating layer; forming a first electrode on the initial first base; etching and removing a portion of the initial first base to form a first base, a first accommodating space, a first driving structure, and a second driving structure, wherein the first accommodating space runs through the initial first base; The step of arranging the second functional structure layer on one side of the first functional structure layer comprises: providing an initial second substrate; forming a second insulating layer on a surface of one side of the initial second substrate; etching a side of the initial second substrate having the second insulating layer to form a main structure of a reflector structure; flipping the initial second substrate having the main structure so that the second insulating layer is fixed on the first substrate facing the first functional structure layer, and the initial second substrate covers the first electrode; forming a reflective layer and a second electrode on a side of the initial second substrate away from the first functional structure layer, the reflective layer being arranged corresponding to the main structure; etching a side of the initial second substrate away from the first functional structure layer to form the first transmission structure and the second transmission structure, so that the torsional reflector assembly is suspended and at least a portion of the first electrode is exposed; The method of arranging the third functional structure layer on the side of the second functional structure layer facing away from the first functional structure layer includes: providing an initial third substrate; forming a third insulating layer on the surface of one side of the initial third substrate; arranging the initial third substrate with the third insulating layer on the second functional structure layer, with the third insulating layer facing the second functional structure layer and covering the second electrode; arranging the third electrode on the side of the initial third substrate facing away from the second functional structure layer; etching and removing part of the initial third substrate and the third insulating layer to form a third substrate, a second accommodating space, a third driving structure and a fourth driving structure, and exposing part of the second electrode, wherein the first accommodating space passes through the initial third substrate and the third insulating layer.

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