Electrostatic MEMS micromirror

Abstract

The application provides an electrostatic MEMS micromirror which can be applied to mobile phones, microphones, cameras, radars, optical devices and the like, comprising a support beam, a micromirror and a driving assembly; the driving assembly comprises a comb tooth frame and driving comb teeth located in the comb tooth frame; the support beam and the micromirror are connected through the comb tooth frame, and two edges of the comb tooth frame connected with the micromirror are located on two sides of a rotation axis determined by an extension line of the support beam; the driving comb teeth comprise at least one pair of comb tooth pairs, each comb tooth pair comprises a moving comb tooth structure and a static comb tooth structure, the moving comb tooth structure comprises a plurality of moving comb teeth, one end of each moving comb tooth is fixed on the comb tooth frame, and the static comb tooth structure is used for generating electrostatic force with the moving comb tooth structure, wherein the distance from the fixed end of the moving comb tooth to the rotation axis is greater than the distance from the other end of the moving comb tooth to the rotation axis. The structure can further improve the rotation angle range and stability of the electrostatic MEMS micromirror.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro electro-mechanical system (MEMS), and in particular to a static MEMS micromirror. BACKGROUND

[0002] Micro electro-mechanical system (MEMS) technology is a technology of integrating electronic, mechanical and optical functional modules into a micron-level system based on microelectronics technology. MEMS technology integrates mechanical components, optical systems, driving components and electrical control systems into a whole unit, which can not only realize information collection, processing and sending or instruction, but also can realize action according to information. Compared with traditional mechanical systems, the system using MEMS technology has the advantages of miniaturization, integration, low energy consumption, low cost, high precision, long service life, and good dynamic performance.

[0003] An important technology in modern optical communication industry is to realize optical interconnection between multiple channels, and the rotary MEMS device is one of the key devices to realize this technology. As shown in FIG. 1, under the action of the driving voltage, the MEMS driver drives the reflecting surface to rotate around the rotating shaft, so that the incident light can be accurately reflected to different ports. Figure 1

[0004] The static MEMS micromirror is one of the rotary micro electro-mechanical system products, which adopts the electrostatic driving mode. The so-called electrostatic driving technology is a technology of using the Coulomb force between electric charges as the driving force for driving. The movable micromirror is rotated by electrostatic action, so as to change the optical path. The rotation angle range and stability of the electrostatic MEMS micromirror directly determine the performance of the device. Expanding the rotation angle range means that the reflected light can enter more ports to realize multi-port optical switching. In addition, the stability of the electrostatic MEMS micromirror will be disturbed by factors such as residual stress, temperature change, external impact, etc. For example, residual stress will cause the device to bend, and external impact will cause the device to break and fail.

[0005] Therefore, how to improve the performance of the electrostatic MEMS micromirror is a technical problem to be solved at present. SUMMARY

[0006] The present application provides a static MEMS micromirror, which can improve the rotation angle range and stability of the electrostatic MEMS micromirror.

[0007] ​In a first aspect, an electrostatic MEMS mirror is provided, comprising: a support beam, a micro-mirror, and a driving assembly; the driving assembly comprises a comb frame and a driving comb located in the comb frame; the support beam and the micro-mirror are connected through the comb frame, two edges of the comb frame connected with the micro-mirror are located on two sides of a rotation axis determined by an extension line of the support beam; the driving comb comprises at least one pair of combs, the pair of combs comprises a moving comb structure and a static comb structure, the moving comb structure comprises a plurality of moving combs, one end of the moving combs is fixed on the comb frame, and the static comb structure is used to generate electrostatic force with the moving comb structure, wherein a distance from the fixed end of the moving combs to the rotation axis is greater than a distance from the other end of the moving combs to the rotation axis.

[0008] In the embodiments of the present application, the comb frame of the electrostatic MEMS mirror is located on both sides of the rotation axis and contacts and supports the micro-mirror through a plurality of points, which increases the moment of inertia of the electrostatic MEMS mirror and improves the stability of the device. In addition, one end of the moving combs is fixed on the comb frame, and since there is no comb frame near the rotation axis, the free end of the moving combs can be extended to the vicinity of the rotation axis to increase the length of the moving combs, thereby effectively improving the driving force of the device and further improving the rotation angle range.

[0009] With reference to the first aspect, in some implementations of the first aspect, the comb frame is symmetrical about the rotation axis.

[0010] In the embodiments of the present application, when the comb frame is symmetrical about the rotation axis, the driving force and the stability of the device are optimal.

[0011] With reference to the first aspect, in some implementations of the first aspect, a vertical distance L0 between the fixed point of the moving comb on the comb frame and the rotation axis satisfies the following relationship: 0.7T1 / sinθ≤L0≤1.1T1 / sinθ, where θ is the maximum rotation angle of the micro-mirror and T1 is the thickness of the moving comb.

[0012] With reference to the first aspect, in some implementations of the first aspect, the electrostatic MEMS mirror further comprises at least one reinforcing rod, both ends of the at least one reinforcing rod are fixed on the comb frame.

[0013] In the embodiments of the present application, the reinforcing rod is introduced into the electrostatic MEMS mirror, which can mechanically connect and reinforce the comb frames on both sides, can suppress the interference of high-order modes, and further improves the stability of the device.

[0014] With reference to the first aspect, in some implementations of the first aspect, the width of the reinforcing rod is 2 times the width of the moving comb.

[0015] In some implementations of the first aspect, the static comb structure includes a plurality of static combs, and the electrostatic MEMS micro-mirror further includes: a groove on the opening of the dynamic comb facing the static comb; and / or a groove on the opening of the static comb facing the dynamic comb.

[0016] In some implementations of the first aspect, the groove is a rectangular groove, and a vertical distance between a center of the groove and the rotation axis is d = h / sin α, where α is a rotation angle of the dynamic comb around the rotation axis, h is a thickness of the groove, α > 0, 0 < T / 2 ≤ h ≤ T, and T is a thickness of the comb where the groove is located.

[0017] In the embodiments of the present application, by etching a groove on the comb pair of the electrostatic MEMS micro-mirror, the distance between the dynamic comb and the static comb in the vertical direction is increased, so that the driving force of the dynamic comb rotating to a specific rotation angle can be enhanced.

[0018] In some implementations of the first aspect, the groove is in a stepped shape.

[0019] In some implementations of the first aspect, the electrostatic MEMS micro-mirror further includes a first driving assembly between the support beam and the driving assembly, or between the driving assembly and the micro-mirror, the first driving assembly including a comb rod on the rotation axis and a driving comb including at least one pair of combs, the pair of combs including a dynamic comb structure and a static comb structure, the dynamic comb structure including a plurality of dynamic combs, one end of the dynamic comb being fixed to the comb rod, and a distance from the fixed end of the dynamic comb to the rotation axis being less than a distance from the other end of the dynamic comb to the rotation axis.

[0020] The electrostatic MEMS micro-mirror in the embodiments of the present application can weaken the attraction force of the vertical comb pair in the y direction (a direction perpendicular to the rotation axis), so as to improve the attraction voltage and enhance the stability of the micro-mirror.

[0021] In the second aspect, a micro-mirror array is provided, including a plurality of electrostatic MEMS micro-mirrors as described in the first aspect and any implementation of the first aspect arranged in an array.

[0022] In the third aspect, an optical switch is provided, including an input port array, an output port array, and at least one micro-mirror array as described in the second aspect, the input port array being configured to receive an optical signal, the optical signal being reflected by the at least one micro-mirror array and then output through the output port array.

[0023] In a fourth aspect, there is provided an optical device comprising a controller and the electrostatic MEMS micro-mirror as described in the first aspect and any implementation thereof or the micro-mirror array as described in the second aspect.

[0024] In a fifth aspect, there is provided a terminal device comprising a controller and the electrostatic MEMS micro-mirror as described in the first aspect and any implementation thereof or the micro-mirror array as described in the second aspect. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a schematic diagram of a rotational MEMS device implementing optical channel switching.

[0026] Figure 2 is a perspective view of an existing electrostatic MEMS micro-mirror.

[0027] Figure 3 is a perspective view of an electrostatic MEMS micro-mirror provided by the present application.

[0028] Figure 4 is a top view of an electrostatic MEMS micro-mirror provided by the present application.

[0029] Figure 5 is a perspective view of a semi-transparent electrostatic MEMS micro-mirror provided by the present application.

[0030] Figure 6 is a schematic diagram of forces acting on a semi-transparent electrostatic MEMS micro-mirror provided by the present application in the y direction.

[0031] Figure 7 is a perspective view of an electrostatic MEMS micro-mirror array provided by the present application.

[0032] Figure 8 is a perspective view of a vertical comb pair provided by the present application.

[0033] Figure 9 is a perspective view of another vertical comb pair provided by the present application.

[0034] Figure 10 is Figure 8 is a left view at A in FIG.

[0035] Figure 11 is a schematic diagram of the principle of driving a vertical comb pair at a specific angle. DETAILED DESCRIPTION

[0036] The technical solutions in the present application will be described below with reference to the accompanying drawings.

[0037] Reference is made to Figure 2 , Figure 2is a perspective view of an existing electrostatic MEMS micro-mirror.

[0038] The electrostatic MEMS micro-mirror comprises a support beam, a micro-mirror, and a driving assembly. The driving assembly is located between the support beam and the micro-mirror, and the same driving assembly is arranged on the left and right sides of the micro-mirror. The driving assembly is generally a conventional vertical comb drive. The driving assembly comprises a comb bar and a driving comb. The comb bar is located on the rotation axis of the electrostatic MEMS micro-mirror. The driving comb comprises at least one pair of comb pairs that are staggered in the vertical direction. The comb pair comprises a static comb structure and a dynamic comb structure. The dynamic comb structure comprises a plurality of dynamic combs. One end of the dynamic comb is fixed on the comb bar. The shape of the comb is generally designed as a simple rectangle or trapezoid. The electrostatic MEMS micro-mirror adopts an electrostatic driving mode. The so-called electrostatic driving technology is a technology that uses the Coulomb force between electric charges as the driving force for driving. Like charges repel each other, and unlike charges attract each other. When the electric field of the two comb pairs changes, the electric field between the combs changes to generate electrostatic force to drive the micro-mirror to twist.

[0039] Referring to Figure 3 , Figure 3 is a perspective view of an electrostatic MEMS micro-mirror provided by the present application. The electrostatic MEMS micro-mirror comprises a support beam, a micro-mirror, and a driving assembly. The driving assembly comprises a comb frame and a driving comb arranged in the comb frame. The support beam and the micro-mirror are connected through the comb frame. Two edge frames connected with the micro-mirror in the comb frame are located on the two sides of the rotation axis determined by the extension line of the support beam.

[0040] Optionally, as shown in Figure 3 , in a specific implementation, one driving assembly is arranged on each of the left and right sides of the micro-mirror. The two edge frames connected with the micro-mirror in each side comb frame are symmetrical about the rotation axis.

[0041] The driving comb comprises at least one pair of combs. The comb pair comprises a dynamic comb structure and a static comb structure. The dynamic comb structure comprises a plurality of dynamic combs. One end of the dynamic comb is fixed on the comb frame. The static comb structure is used to generate electrostatic force with the dynamic comb structure to drive the micro-mirror to move or rotate around the rotation axis with the comb frame. The distance from the fixed end of the dynamic comb to the rotation axis is greater than the distance from the other end of the dynamic comb to the rotation axis.

[0042] It should be understood that the comb pair herein can be a parallel comb pair or a vertical comb pair, which is not limited in the present application.

[0043] Optionally, the dynamic comb and the static comb can be a conventional rectangle or trapezoid.

[0044] Optionally, the shape of the micro-mirror is not limited in the present application. For example, the micro-mirror mirror surface can be circular, rectangular, elliptical, etc.

[0045] In one implementation, the electrostatic MEMS micromirror can further include at least one reinforcing rod, both ends of the reinforcing rod being fixed to the comb tooth frame and connecting the comb tooth frames on the upper and lower sides. Generally, the reinforcing rod is perpendicular to the rotation axis, and the width of the reinforcing rod is greater than 2 times the width of the comb tooth or the width of the support beam.

[0046] For the sake of uniform description, the width of a component in this application refers to the distance of the component in the x direction, the length of a component in this application refers to the distance of the component in the y direction, and the thickness of a component in this application refers to the distance of the component in the z direction.

[0047] It should also be understood that the verticality here is only for the convenience of describing the position of the reinforcing rod, and some deviations can be caused in actual production due to manufacturing process or manufacturing precision, and it does not mean that the reinforcing rod must be completely perpendicular to the rotation axis.

[0048] As can be seen from the above, the frame of the comb tooth frame of the novel electrostatic MEMS micromirror proposed in this application is located on both sides of the rotation axis, and is in contact with and supports the micromirror through multiple points. The electrostatic MEMS micromirror in this application can also be referred to as a reverse electrostatic MEMS micromirror. The reverse MEMS micromirror structure can not only improve the stability of the device, but also increase the rotation angle range of the device. In addition, the reinforcing rod is introduced in this reverse design to mechanically connect and reinforce the comb tooth frames on both sides, which can suppress the interference of high-order modes and further improve the stability of the device.

[0049] The reasons why the reverse MEMS micromirror structure can improve the rotation angle range and stability of the micromirror and how to adjust the maximum rotation angle of the micromirror will be described below in combination with Figure 4 The reasons why the reverse MEMS micromirror structure can improve the rotation angle range and stability of the micromirror and how to adjust the maximum rotation angle of the micromirror will be described below in combination with

[0050] Reference will be made to Figure 4 , Figure 4 is a top view of an electrostatic MEMS micromirror provided by the present application. It should be understood that Figure 3 and Figure 4 are schematic views of the same electrostatic MEMS micromirror at different angles. As shown in Figure 4 , the length of the moving comb tooth is L1, the vertical distance between the suspension point of the moving comb tooth on the comb tooth frame and the rotation axis is L0, and the vertical distance between the center position of any comb tooth frame connected to the micromirror in the y direction and the rotation axis is L f .

[0051] (1) L1 is proportional to the driving capacity of the driving assembly. Due to the reverse design, there is no comb tooth frame near the rotation axis, so this part of the space can be utilized. Specifically, the static comb tooth can be infinitely close to the rotation axis along the y direction, so that the free end of the moving comb tooth can be extended to the vicinity of the rotation axis to increase the length L1 of the moving comb tooth, which can effectively improve the driving force of the micromirror and further improve the rotation angle range.

[0052] (2)L f It is proportional to the moment of inertia of the micromirror device. The moment of inertia is a geometric quantity that is usually used to describe the properties of the cross section that resist bending. The larger the moment of inertia, the higher the stability of the device. It can be seen that Figure 2 The vertical distance between the center position of the middle comb frame in the y direction and the rotation axis is L p , L f The length is significantly greater than L p Therefore, the inverse design in this application increases the moment of inertia of the electrostatic MEMS micromirror, thereby improving the stability of the device.

[0053] (3) L0 can be adjusted according to the maximum rotation angle θ required by the micromirror device, and the range of L0 can be determined according to formula (1). Wherein, T1 is the thickness of the movable comb teeth, which is the thickness of the movable comb teeth in the z direction:

[0054] 0.7T1 / sinθ≤L0≤1.1T1 / sinθ (1)

[0055] See also Figure 5 , Figure 5 This is a three-dimensional diagram of a semi-reflective electrostatic MEMS micromirror provided by this application. It can be seen that the semi-reflective MEMS micromirror is Figure 3 The difference between the MEMS micromirror shown in the figure is the structure of the driving component. The driving component of the semi-reflective MEMS micromirror is composed of Figure 2 Conventional drive components and Figure 3 The trans-drive components in the

[0056] Optional, such as Figure 5 As shown, the conventional drive assembly may be located between the support beam and the trans-drive assembly.

[0057] Optionally, a conventional driving component may also be located between the trans-driving component and the micromirror.

[0058] The advantage of this semi-reversed design is that it can weaken the attraction of the vertical comb teeth in the y direction, thereby increasing the pull-in voltage and enhancing the stability of the micromirror. Figure 6 The design principle of the semi-reflective MEMS micromirror is specifically explained.

[0059] like Figure 6 As shown, the movable comb teeth rotate around the rotation axis. Figure 2 In the conventional design of the drive assembly, since the moving comb teeth are located near the rotation axis, the electrostatic attraction of the static comb teeth to the moving comb teeth is generally in the negative direction of the y-axis, and the magnitude is F y2 ;and Figure 3The electrostatic attraction force of the static comb to the dynamic comb is generally in the positive direction of the y-axis, and the size of the electrostatic attraction force is F y1 The semi-reverse design in this embodiment combines the conventional design and the reverse design, and can balance the external force in the y direction on the dynamic comb, thereby improving the stability of the device. In actual applications, the length ratio A of the driving assembly of the reverse design and the driving assembly of the conventional design can be adjusted as needed, for example, A = F y2 :F y1 , and the external force in the y direction on the dynamic comb is the smallest.

[0060] Referring to Figure 7 , Figure 7 is a perspective view of an electrostatic MEMS micromirror array provided in the present application. The array micromirror is composed of a plurality of single electrostatic MEMS micromirrors, wherein any one of the electrostatic MEMS micromirrors in the electrostatic MEMS micromirror array can be any one of the reverse electrostatic MEMS micromirror or the semi-reverse electrostatic MEMS micromirror provided in the present application.

[0061] The structure of the reverse electrostatic MEMS micromirror or the semi-reverse electrostatic MEMS micromirror is described in detail above, and the structure of a vertical comb pair provided in an embodiment of the present application is described below. Figure 2 The structure of the vertical comb pair in the driving assembly of the conventional design in Figure 3 and the driving assembly of the reverse design in is optimized, and the optimized vertical comb pair can further expand the rotation angle range of the micromirror.

[0062] Figure 8 Referring to Figure 8 , Figure 8 can be regarded as part of the driving assembly of the conventional design in Figure 2 , and can also be regarded as part of the driving assembly of the reverse design in Figure 3 . For ease of description, the groove located on the dynamic comb is referred to as a first groove, and the groove located on the static comb is referred to as a second groove.

[0063] The vertical comb pair includes a first groove located on the dynamic comb, and the opening of the first groove faces the static comb; and / or a second groove located on the static comb, and the opening of the second groove faces the dynamic comb, wherein the first groove and the second groove are used to enhance the driving force between the static comb structure and the dynamic comb structure.

[0064] Optionally, as shown in Figure 9 , the first groove and the second groove can be rectangular grooves or stepped grooves. It should be understood that Figure 9It is only schematically shown that the first groove is a stepped groove and the second groove is a rectangular groove.

[0065] It should also be understood that Figure 8 A vertical comb tooth pair including a first groove and a second groove, wherein the first groove and the second groove are rectangular grooves, is only schematically provided.

[0066] It should be understood that the improved vertical comb teeth in this embodiment can be applied to any vertical comb teeth driver, and this application does not limit this.

[0067] See also Figure 10 , Figure 10 yes Figure 8 Left view at point A in the middle. Figure 10 The first groove is located on the moving comb teeth, and the second groove is located on the stationary comb teeth. Both the first groove and the second groove are rectangular grooves. Since the stationary comb teeth are closer to the rotation axis than the moving comb teeth in the y direction, Figure 10 It can be seen as Figure 3 Left view of the vertical comb tooth pair in the reverse design.

[0068] like Figure 10 As shown, the dynamic comb teeth have a length of L1 and a thickness of T1. The first groove has a length of l1 and a thickness of h1, and the vertical distance from the centroid of the first groove to the rotation axis is d1. The static comb teeth have a length of L2 and a thickness of T2. The second groove has a length of l2 and a thickness of h2, and the vertical distance from the centroid of the second groove to the rotation axis is d2.

[0069] It can be understood that since grooves are etched on the vertical comb teeth provided in the present application, the vertical spacing between the upper and lower comb teeth becomes larger, so a driving force will be generated when the movable comb teeth rotate at a large angle.

[0070] Next, combine Figure 11 The principle that the first groove and the second groove can enhance the driving force between the static comb tooth structure and the dynamic comb tooth structure is specifically described.

[0071] It should be noted that Figure 10 and Figure 11 For the same left view, Figure 11 For the specific parameters of the dynamic comb teeth, static comb teeth, first groove and second groove, please refer to Figure 10 The description in , will not be repeated here. Figure 11 As shown, the dynamic comb teeth are divided into three areas A1, A2, and A3 by the first groove, and the static comb teeth are divided into two areas B1 and B2 by the second groove.

[0072] (1) Figure 11As shown in (a), the moving comb teeth and the fixed comb teeth are not in the same plane without electricity. When the moving comb teeth just start to rotate, the A1 and B1 regions are close in the y direction. Under the condition that the fixed comb teeth are grounded and the moving comb teeth are connected to high voltage, electrostatic force is generated between the two regions due to the voltage difference, forming the first level of driving. At this time, the electrostatic force generated in other regions is weak due to the long distance, and the contribution to the driving force can be ignored.

[0073] (2) As shown in (b), when the moving comb teeth rotate to an angle α1 (α1>0), the A3 and B2 regions overlap in the y direction, and the electrostatic force becomes strong, forming the second level of driving. The angle α1 is determined by the position of the first groove, where d1=h1 / sinα1, and generally T1 / 2≤h1≤T1, depending on the requirements of different devices, and generally 1°≤α1≤8°. The driving ability of this level of driving is represented by the moment M1 required for rotation, and M1∝d1*l1. Figure 11 (3) As shown in (c), when the moving comb teeth rotate to an angle α2 (α2>0), the A2 and B2 regions begin to overlap in the y direction, and the electrostatic force becomes strong, forming the third level of driving. The angle α2 is determined by the position of the second groove, where d2=h2 / sinα2, and generally T2 / 2≤h2≤T2, depending on the requirements of different devices, and generally 8°≤α2≤15°. The driving ability of this level of driving is represented by the moment M2 required for rotation, and M2∝d2*l2.

[0074] Figure 11 It should be understood that and

[0075] only schematically shows a three-level driving vertical comb pair. For other multi-level driving vertical comb pairs, the driving force at other rotation angles can be improved by increasing the number of comb grooves. Figure 10 Figure 11 The multi-level driving vertical comb structure provided in the present application can be used to enhance the driving force at a specific rotation angle or to adjust the voltage-rotation angle relationship of the micro mirror by etching specific grooves on the moving comb teeth and / or the fixed comb teeth. The centroid and thickness of the grooves determine the improvement effect of the micro mirror rotation angle.

[0076] The present application also provides an optical switch, which comprises an input port array, an output port array, and at least one micro mirror array as shown in , wherein the input port array is used to receive an optical signal, and the optical signal is reflected by the at least one micro mirror array and then output through the output port array.

[0077] Figure 7 The present application also provides an optical device, which comprises a controller and any one of the electrostatic MEMS micro mirrors provided in the present application or

[0078] The present application also provides an optical device, which comprises a controller and any one of the electrostatic MEMS micro mirrors provided in the present application or Figure 7 ​The micro-mirror array is shown in FIG. 1. As an example, the optical device can be a wavelength selective switch (WSS), an optical power monitor (OPM), a variable optical attenuator (VOA), etc. Also proposed is a terminal device comprising a controller, and any one of the electrostatic MEMS micro-mirrors or Figure 7 The micro-mirror array is shown in FIG. 1. As an example, the optical device can be a wavelength selective switch (WSS), an optical power monitor (OPM), a variable optical attenuator (VOA), etc. Also proposed is a terminal device comprising a controller, and any one of the electrostatic MEMS micro-mirrors or

[0079] The structure and principle of the multi-stage driving vertical comb teeth are described in detail above. Since the structure of the comb teeth is improved, the manufacturing process also needs to be improved accordingly. Taking the three-stage driving vertical comb teeth in FIG. 1 as an example, the related manufacturing process flow is briefly described below. Figure 10 The structure and principle of the multi-stage driving vertical comb teeth are described in detail above. Since the structure of the comb teeth is improved, the manufacturing process also needs to be improved accordingly. Taking the three-stage driving vertical comb teeth in FIG. 1 as an example, the related manufacturing process flow is briefly described below.

[0080] (1) Use the glue throwing process to make a mask on the front surface of the wafer 1, and then etch the second groove.

[0081] (2) Use the glue throwing process to make a mask on the front surface of the wafer 1, and then etch the second groove.

[0082] (3) Etch the first groove on the back surface of the wafer 2.

[0083] (4) Bond the wafer 2 with the wafer 1 to form the support anchor point.

[0084] (5) Grind the wafer from the front surface of the wafer 2 to the specified thickness.

[0085] (6) Use the glue throwing process to make a mask on the front surface of the wafer 2, and then etch the moving comb teeth.

[0086] For the step-shaped comb tooth groove, the glue throwing process needs to be used multiple times to form a mask, and the comb tooth groove needs to be etched multiple times.

[0087] Note that the above is only a preferred embodiment of the present application. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and that various obvious changes, re-adjustments, mutual combinations and substitutions can be made by those skilled in the art without departing from the scope of the present application. Therefore, although the present application has been described in detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. An electrostatic MEMS micromirror, characterized by, Comprising: a support beam, a micromirror and a driving assembly; the driving assembly comprises a comb frame and driving combs in the comb frame; the support beam and the micromirror are connected through the comb frame, and two edges of the comb frame connected with the micromirror are located on two sides of a rotation axis determined by an extension line of the support beam; the driving combs comprise at least one pair of comb pairs, each comb pair comprises a moving comb structure and a static comb structure, the moving comb structure comprises a plurality of moving combs, one end of each moving comb is fixed on the comb frame, and the static comb structure is used to generate electrostatic force with the moving comb structure, wherein the distance from the fixed end of the moving comb to the rotation axis is greater than the distance from the other end of the moving comb to the rotation axis.

2. The electrostatic MEMS mirror of claim 1, wherein, The comb frame is symmetrical about the rotation axis.

3. The electrostatic MEMS mirror according to claim 1 or 2, wherein, The vertical distance L0 between the fixed point of the moving comb on the comb frame and the rotation axis satisfies the following relationship: 0.7T1 / sinθ≤L0≤1.1T1 / sinθ, wherein θ is the maximum rotation angle of the micromirror, and T1 is the thickness of the moving comb.

4. The electrostatic MEMS mirror according to any one of claims 1-3, wherein, The electrostatic MEMS micromirror further comprises at least one reinforcing rod, both ends of the at least one reinforcing rod are fixed on the comb frame.

5. The electrostatic MEMS mirror of claim 4, wherein, The width of the reinforcing rod is 2 times the width of the moving comb.

6. The electrostatic MEMS mirror according to any one of claims 1-5, wherein, The static comb structure comprises a plurality of static combs, and the electrostatic MEMS micromirror further comprises: a groove on the static comb facing the opening of the moving comb; and / or a groove on the moving comb facing the opening of the static comb. The groove is a rectangular groove, and the vertical distance between the center of the groove and the rotation axis is d=h / sinα, wherein α is the rotation angle of the moving comb around the rotation axis, h is the thickness of the groove, α>0, 0 7. The electrostatic MEMS mirror of claim 6, wherein, The cross-sectional shape of the groove is stepped.

8. The electrostatic MEMS mirror of claim 6, wherein, Further comprising:

9. The electrostatic MEMS mirror of any one of claims 1-8, wherein, a first driving assembly between the support beam and the driving assembly, or a first driving assembly between the driving assembly and the micromirror; the first driving assembly comprises a comb rod and driving combs, and the comb rod is located on the rotation axis; the driving combs comprise at least one pair of comb pairs, each comb pair comprises a moving comb structure and a static comb structure, the moving comb structure comprises a plurality of moving combs, one end of each moving comb is fixed on the comb rod, and the distance from the fixed end of the moving comb to the rotation axis is less than the distance from the other end of the moving comb to the rotation axis. The micromirror array comprises a plurality of electrostatic MEMS micromirrors arranged in an array according to any one of claims 1 to 9.

10. A micromirror array, characterized by The optical switch comprises an input port array, an output port array and at least one micromirror array according to claim 10, the input port array is used to receive an optical signal, the optical signal is reflected by the at least one micromirror array and then output through the output port array.

11. An optical switch, characterized by Comprising a controller and an electrostatic MEMS micromirror according to any one of claims 1 to 8 or a micromirror array according to claim 10.

12. An optical device, characterized by ​

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