MEMS micromirror structure and MEMS micromirror integrated product
By setting a transition connection end and reinforcement structure with appropriate width in the first rotation axis structure of the MEMS micromirror structure, the problem of dynamic deformation of the mirror surface at high frequencies is solved, and a higher mirror utilization rate is achieved.
Patent Information
- Application Number
- CN202421553067.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-02
- Publication Date
- 2025-05-20
- Estimated Expiration
- 2034-07-02
AI Technical Summary
When the existing MEMS micromirror structure works at higher frequencies, due to the inertial force, the mirror surface of the reflector will undergo dynamic deformation, resulting in the flatness of the mirror surface being affected and the imaging quality.
A MEMS micromirror structure is designed, and a transition connection end with a width of not less than one-half of the short axis length of the mirror is provided in the first rotational axis structure between the mirror and the movable frame, and a reinforcement structure is provided on the back of the mirror and the transition connection end to reduce dynamic deformation.
The dynamic deformation at the connection between the first rotating shaft structure and the mirror is effectively suppressed, and the dynamic deformation difference of the entire mirror is small, which improves the utilization rate of the mirror.
Smart Images
Figure CN222887733U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of micro-optoelectromechanical technology, and particularly to a MEMS micromirror structure and a MEMS micromirror integrated product. Background Art
[0002] A micro-electro-mechanical system (MEMS) galvanometer mirror is a device manufactured using MEMS technology, in which a mirror deflects according to a certain rule under the action of a driver. Currently, MEMS galvanometer mirrors are widely used in many fields, such as optical communication, laser projection, three-dimensional imaging, lidar, etc.
[0003] The utility model person of the present application found in the research that in the existing MEMS micromirror structure, the operating frequencies of the MEMS micromirror structure in different application scenarios are different, ranging from several hundred Hz to several tens of kHz. When the MEMS micromirror structure operates at a higher frequency, due to the action of inertial force, the mirror surface of the mirror will deform, resulting in the influence on the flatness of the mirror surface, which is called dynamic deformation. The dynamic deformation of the mirror surface will cause optical distortion of pixels and images, affecting the imaging quality. Since the dynamic deformation of the mirror surface is generated during the working process, it will change with the working state and instantaneous angle of the MEMS micromirror structure, and the deformation amounts at different positions on the mirror surface are also often different. Therefore, it is difficult to compensate from the outside through detection based on dynamic deformation, and this deformation should be mainly reduced through design. Summary of the Utility Model
[0004] To solve the existing technical problems, the present application provides a MEMS micromirror structure and a MEMS micromirror integrated product that can effectively reduce the dynamic deformation of the mirror surface and improve the utilization rate of the mirror surface.
[0005] In a first aspect, the present application provides a MEMS micromirror structure, including:
[0006] A mirror;
[0007] A frame for carrying the mirror, including a fixed structure and a movable frame;
[0008] A first rotating shaft structure for connecting the mirror and the movable frame, supporting the mirror to perform a torsional motion with the first rotating shaft structure as the axis;
[0009] A second rotating shaft structure for connecting the movable frame and the fixed structure, supporting the movable frame to drive the mirror to perform a torsional motion with the second rotating shaft structure as the axis;
[0010] Among them, the first rotating shaft structure includes a beam body and a transition connection end connected between the beam body and the mirror. The width of the transition connection end is not less than half of the minor axis length of the mirror, and the width of the beam body is not less than the width of the transition connection end;
[0011] A reinforcement structure is located on the back of the mirror and the transition connection end. The reinforcement structure is formed by connecting a straight segment and a curved segment end to end to form a closed structure.
[0012] In a second aspect, the present application provides a MEMS micromirror integrated product, including the MEMS micromirror structure according to any embodiment of the present application;
[0013] The MEMS micromirror integrated product is one of the following: an optical communication system, a lidar system, a laser projection system, and a three-dimensional imaging system.
[0014] In the MEMS micromirror structure provided in the above embodiment, the first rotating shaft structure connected between the mirror and the movable frame includes a beam body and a transition connection end connected between the beam body and the mirror. The width of the transition connection end is not less than half of the minor axis length of the mirror, and the width of the beam body is not less than the width of the transition connection end. In this way, by designing the width of the transition connection end to be not less than half of the minor axis length of the mirror, and the width of the beam body is not less than the width of the transition connection end, and a reinforcement structure formed by connecting a straight segment and a curved segment end to end is provided on the back of the mirror and the transition connection end. At the same angle and frequency of the MEMS micromirror structure, the dynamic deformation at the connection between the first rotating shaft structure and the mirror can be effectively suppressed, and the dynamic deformation difference of the entire mirror surface is small, effectively improving the mirror surface utilization rate.
[0015] In the above embodiment, the MEMS micromirror integrated product and the corresponding MEMS micromirror structure embodiment belong to the same concept, and thus have the same technical effects as each MEMS micromirror structure embodiment, which will not be elaborated here. Description of the Drawings
[0016] Figure 1 It is a schematic structural diagram of a MEMS micromirror structure in an embodiment.
[0017] Figure 2 It is Figure 1 a schematic structural diagram of the first rotating shaft structure of the MEMS micromirror structure shown.
[0018] Figure 3 It is Figure 1 a schematic structural diagram of the connection between the first rotating shaft structure and the mirror in the MEMS micromirror structure shown.
[0019] Figure 4 It is Figure 1Schematic diagram of the back structure where the first rotating shaft structure is connected to the mirror in the shown MEMS mirror structure.
[0020] Figure 5 Schematic diagram of the structure where the rotating shaft structure is connected to the mirror in an example.
[0021] Figure 6 For Figure 5 Schematic diagram of the dynamic deformation simulation result of the mirror in the shown example.
[0022] Figure 7 Schematic diagram of the back structure where the rotating shaft structure is connected to the mirror in another example.
[0023] Figure 8 For Figure 7 Schematic diagram of the dynamic deformation simulation result of the mirror in the shown example.
[0024] Figure 9 For Figure 3 Cross-sectional view along line B-B in
[0025] Figure 10 For Figure 1 Schematic diagram of the dynamic deformation simulation result of the mirror in the MEMS mirror structure shown in
[0026] Explanation of component symbols:
[0027] Frame 10, fixed structure 12, movable frame 11, coil 15, mirror 30, reinforcement ring 31, second rotating shaft structure 40, first connection end 41, second connection end 42, main beam part 43, first rotating shaft structure 50, linear beam 50', beam body 51, central beam 511, extended beam 512, first extended beam 5121, second extended beam 5122, transition connection end 52, reinforcement structure 70, first straight segment 71, second straight segment 72, third straight segment 73, fourth straight segment 74, curved segment 75 Detailed implementation manners
[0028] The technical solution of the present utility model will be further elaborated in detail below in conjunction with the accompanying drawings of the specification and specific embodiments.
[0029] In order to make the purpose, technical solution and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings. The described embodiments should not be regarded as limitations of the present application. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present application.
[0030] In the following description, the expression "some embodiments" describes a subset of all possible embodiments. It should be noted that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.
[0031] In the following description, the terms "first", "second", and "third" are only used to distinguish similar objects and do not represent a specific order for the objects. It can be understood that "first", "second", and "third" can be interchanged in a specific order or sequence when permitted, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.
[0032] Please refer to Figure 1 , which is a MEMS mirror structure provided by an embodiment of the present application. The MEMS mirror structure includes: a mirror 30; a frame 10 for carrying the mirror 30, including a fixed structure 12 and a movable frame 11; a first rotating shaft structure 50 for connecting the mirror 30 and the movable frame 11, supporting the mirror 30 to perform a torsional movement about the first rotating shaft structure 50 as an axis; a second rotating shaft structure 40 for connecting the movable frame 11 and the fixed structure 12, supporting the movable frame 11 to drive the mirror 30 to perform a torsional movement about the second rotating shaft structure 40 as an axis; wherein, the first rotating shaft structure 50 includes a beam body 51 and a transition connection end 52 connected between the beam body 51 and the mirror 30, the width of the transition connection end 52 is not less than half of the minor axis length of the mirror 30, and the width of the beam body 51 is not less than the width of the transition connection end 52; a reinforcement structure 70 located on the back of the mirror 30 and the transition connection end 52, and the reinforcement structure 70 is formed by connecting a straight line segment and a curved line segment end to end to form a closed structure.
[0033] In an alternative example, the first rotating shaft structure 50 is a fast-rotating shaft beam, and the second rotating shaft structure 40 is a slow-rotating shaft beam.
[0034] Among them, the MEMS mirror structure further includes a driver. According to different driver types, the MEMS mirror structure can generally be divided into electrostatic drive, electromagnetic drive, piezoelectric drive, and electrothermal drive. Under the action of the driver, the movable frame 11 twists around the axis where the slow rotation shaft beam is located, and the mirror 30 is connected to the movable frame 11. The mirror 30 can twist around the axis where the slow rotation shaft beam is located together with the movable frame 11; at the same time, under the action of the driver, the movable frame 11 twists around the axis where the fast rotation shaft beam is located, driving the mirror 30 to twist around the axis where the fast rotation shaft beam is located; thus, the mirror 30 can twist in the first direction (such as the y-axis direction) with the slow rotation shaft beam as the axis and twist in the second direction (such as the x-axis direction) with the fast rotation shaft beam as the axis. The mirror 30 deflects in the first direction and the second direction at a predetermined frequency and deflection angle to reverse the optical path direction or adjust the optical path deflection angle to adjust the direction of the incident light beam. Specifically, the mirror surface of the mirror 30 resonates at dozens of KHz around the fast rotation shaft beam (the first rotation shaft structure 50), and the mirror 30 and the movable frame 11 together perform a quasi-static movement around the slow rotation shaft beam (the second rotation shaft structure 40) at dozens of Hz. The MEMS mirror structure supports the mirror 30 through the first rotation shaft structure 50 and the second rotation shaft structure 40 to achieve two-dimensional scanning.
[0035] In this embodiment, the driver includes a coil 15 disposed on the movable frame 11 and a magnet group (not shown in the figure) disposed below the frame 10. The coil 15 is disposed on the upper surface of the movable frame 11. After being energized, it is subjected to an electromagnetic force in the magnetic field, driving the movable frame 11 and the mirror 30 surface to twist around the axis where the slow rotation shaft beam is located and around the axis where the fast rotation shaft beam is located respectively.
[0036] The reinforcement structure 70 is formed by connecting a plurality of straight line segments and curved line segments end to end to form a closed structure, and is disposed on the back of the mirror 30 and the transition connection end 52. Thus, the design that the reinforcement structure 70 is partially disposed on the back of the transition connection end 52 and partially disposed on the back of the mirror 30 and jointly connected to form an integral closed structure can further effectively suppress the maximum dynamic deformation at the connection between the first rotation shaft structure 50 and the mirror 30.
[0037] In the MEMS mirror structure provided by the above embodiments, the first rotating shaft structure 50 connected between the mirror 30 and the movable frame 11 includes a beam body 51 and a transition connection end 52 connected between the beam body 51 and the mirror 30. The width of the transition connection end 52 is not less than half of the minor axis length of the mirror 30, and the width of the beam body 51 is not less than the width of the transition connection end 52. Thus, through the design of the widened transition connection end 52 at the connection between the first rotating shaft structure 50 and the mirror 30, the length of the transition connection end 52 is adjusted according to the size of the mirror 30. By setting the width of the transition connection end 52 not less than half of the minor axis length of the mirror 30, and the width of the beam body 51 not less than the width of the transition connection end 52, and a reinforcement structure formed by connecting the straight line segment and the curve segment end to end is provided on the back of the mirror 30 and the transition connection end 52, the MEMS mirror structure can effectively suppress the maximum dynamic deformation at the connection between the first rotating shaft structure 50 and the mirror 30 at the same torsion angle and frequency, and the dynamic deformation difference of the entire mirror surface is small, effectively improving the mirror surface utilization rate.
[0038] Please refer to Figure 2 , in the first rotating shaft structure 50, the beam body 51 includes a central beam 511 and extension beams 512 extending from one end of the central beam 511 away from the movable frame 11 to opposite sides respectively. The beam body 51 of the first rotating shaft structure 50 is symmetrically arranged with respect to the central beam 511. The beam body 51 of the first rotating shaft structure 50 is in a serpentine shape formed by the central beam 511 and the extension beams 512. The width of the transition connection end 52 at the connection between the serpentine beam body 51 and the mirror 30 is designed not less than half of the minor axis length of the mirror 30, and the overall width of the serpentine beam body 51 is not less than the width of the transition connection end 52. Such a design can effectively suppress the dynamic deformation at the connection between the mirror 30 and the first rotating shaft structure 50 and improve the mirror surface utilization rate of the mirror 30. In this embodiment, the width of the transition connection end 52 can be basically equal to the width of the beam body 51. The design of the larger width of the transition connection end 52 in the first rotating shaft structure 50 improves the mirror surface utilization rate of the mirror 30 and is beneficial to reducing the overall size of the chip.
[0039] Optionally, in the first rotating shaft structure 50, the width of the central beam 511 is greater than the width of the extension beam 512. The central beam 511 is located on the axis of the first rotating shaft structure 50. Under the action of the driving force, the mirror 30 twists around the first rotating shaft structure 50. Specifically, it means that the mirror 30 twists with the central beam 511 in the first rotating shaft structure 50 as the axis. The design of widening the width of the central beam 511 is beneficial to reducing the maximum stress on the beam. Optionally, the extension beams 512 are symmetrically arranged relative to the central beam 511. The first rotating shaft structure 50 in a symmetrical form is beneficial to improving the balance of the mirror 30 twisting around the first rotating shaft structure 50. At the same angle, the maximum stress generated on the first rotating shaft structure 50 is smaller, and the working angle of the mirror 30 can be larger. Among them, the number of extension beams 512 on different sides of the central beam 511 can be one or more, and the widths of different extension beams 512 can also be the same or different. In this embodiment, the first rotating shaft structure 50 is integrally formed into a serpentine shape in which the width of the central beam 511 located on the rotation axis is relatively large and the width of the extension beams 512 symmetrically distributed relative to the central beam 511 is relatively small. The first rotating shaft structure 50 is formed by a central beam 511 and multiple non-uniform-width straight line segments of multiple extension beams 512, which can make the stress evenly distributed on the first torsion shaft structure 50 and improve the reliability of the first rotating shaft structure 50 to support the mirror 30 to twist along its axis direction.
[0040] Optionally, the number of extension beams 512 on each side of the central beam 511 is multiple, and the widths of the multiple extension beams 512 on the same side of the central beam 511 gradually decrease in the direction away from the central beam 511. Among them, the width of the central beam 511 and the widths of the multiple extension beams 512 on the same side of the central beam 511 decrease in sequence. In this embodiment, taking the example that each side of the central beam 511 includes a first extension beam 5121 and a second extension beam 5122, the size relationship between the width b1 of the central beam 511, the width b2 of the first extension beam 5121 on its same side, and the width b3 of the second extension beam 5122 satisfies: b1 > b2 > b3. The first rotating shaft structure 50 is an axially symmetric folded beam composed of multiple straight line segments, that is, it can improve the torsional stiffness of the first rotating shaft structure 50, realize high-frequency vibration, and reduce the maximum stress on the beam, making the stress evenly distributed on the beam and avoiding stress concentration.
[0041] In some embodiments, please refer to Figure 3 , the mirror 30 is an elliptical mirror surface, the short axis length of the mirror 30 is b, and the calculation formula for the width W of the transition connection end 52 is as follows:
[0042] W = (0.3 - 0.5) * b.
[0043] The long axis length of the mirror 30 is a, and the calculation formula for the length L of the transition connection end 52 is as follows:
[0044] L = (0.1 - 0.2) * a / 2.
[0045] Wherein, the width W direction of the transition connection end 52 is the same as the short axis direction of the mirror 30, that is, the axis direction of the second rotating shaft structure 40; the length L direction of the transition connection end 52 is the same as the long axis direction of the mirror 30, that is, the axis direction of the first rotating shaft structure 50. By designing the length and width of the transition connection end 52 to meet a certain ratio of the short axis and long axis of the mirror 30, when the size of the mirror 30 is determined, the transition connection end 52 can be determined according to the size of the mirror 30, effectively suppressing the maximum dynamic deformation at the connection between the mirror 30 and the first rotating shaft structure 50.
[0046] In some embodiments, the second rotating shaft structure 40 includes a first connection end 41 connected to the movable frame 11, a main beam portion 43 formed by bending inward from the first connection end 41 and including a plurality of parallel straight segments, and a second connection end 42 connecting the main beam portion 43 to the fixed structure 12; among the plurality of straight segments, the first connection end 41, the second connection end 42, and one of the straight segments are located on the axis of the second rotating shaft structure 40. Wherein, the plurality of straight segments in the main beam portion 43 are arranged parallel and spaced apart, and the starting point where the first connection end 41 is connected to the movable frame 11 and the ending point where the second connection end 42 is connected to the fixed structure 12 are both located on the axis of the second rotating shaft structure 40. In this embodiment, the first connection end 41 connects one outermost straight segment in the main beam portion 43 to the movable frame 11, the second connection end 42 connects the other outermost straight segment in the main beam portion 43 to the fixed structure 12, the first connection end 41 and the second connection end 12 are respectively linear, and the connection between at least one straight segment in the main beam portion 43 and the fixed structure 12 is aligned and located on the axis of the second rotating shaft structure 40. Among the plurality of straight segments of the second rotating shaft structure 40, one of the straight segments is set to coincide with the axis of the second rotating shaft structure 40, so that the plurality of straight segments of the second rotating shaft structure 40 form a symmetric state, and the second rotating shaft structure 40 including the first connection end 41 and the second connection end 42 is in an overall centrosymmetric state. In this way, it is more beneficial to improve the control of the torsional angle accuracy of the second rotating shaft structure 40.
[0047] In some embodiments, please refer to Figure 4 , the widened width design at the transition connection end 52 of the first rotating shaft structure 50 facilitates the setting of the reinforcement structure 70 on the back of the transition connection end 52, reducing the dynamic deformation of the mirror 30. As Figure 4As shown, the reinforcement structure 70 includes a portion corresponding to the transition connection end 52 and a portion corresponding to the mirror 30. The reinforcement structure 70 is symmetric with respect to the axis of the first rotating shaft structure 50 and symmetric with respect to the axis of the second rotating shaft structure 40 respectively. The setting of the reinforcement structure 70 can reduce the mirror thickness of the mirror 30 and effectively reduce the mirror moment of inertia, and ensure that the maximum dynamic deformation at the connection between the mirror 30 and the first rotating shaft structure 50 can be effectively suppressed, and the dynamic deformation of the mirror surface of the mirror 30 during operation can be effectively suppressed.
[0048] Regarding the widened design of the transition connection end 52 and the design in which part of the reinforcement structure 70 is arranged at the transition connection end 52 and part is arranged on the back surface of the mirror 30, it is an improved solution obtained by the applicant of the present application through the analysis of various examples. Please refer to Figure 5 and Figure 6 , which is a schematic structural diagram of the connection between the rotating shaft structure and the mirror in an example. In this example, the rotating shaft structure is a straight beam 50'. Since the mirror surface needs to vibrate at a relatively high frequency, in order to reduce the driving power consumption, the torsional beam stiffness needs to be small, so the moment of inertia must be reduced. When the mirror size is determined, reducing the mirror thickness can effectively reduce the mirror moment of inertia, and at the same time ensure that the natural frequency of the MEMS mirror structure is in the dozens of KHz. However, as Figure 6 shown, when the straight beam 50' is connected to the mirror 30, it will cause a large dynamic deformation of the mirror surface during operation, and the deformation is the largest near the connection between the mirror surface and the torsional beam. Please refer to Figure 7 and Figure 8 , which is a schematic structural diagram of the connection between the rotating shaft structure and the mirror in another example. Compared with the example shown in Figure 5 , a ring-shaped reinforcement ring 31 is added to the back surface of the mirror 30. However, as Figure 8 shown, at the same torsional angle and frequency of the mirror 30, the reinforcement ring 31 on the back of the mirror surface can suppress the dynamic deformation of the mirror surface, but there is still a large deformation near the connection between the mirror surface and the torsional beam, and the maximum dynamic deformation at the connection between the mirror surface and the beam is 360 nm. In the embodiment of the present application, by forming a transition connection end 52 with a length not less than half of the minor axis length of the mirror 30 at the connection between the first rotating shaft structure 50 and the mirror 30, and then arranging the reinforcement structure 70 on the back surfaces of the transition connection end 52 and the mirror 30, a better suppression effect can be achieved on both the maximum dynamic deformation at the connection between the mirror surface and the torsional beam and the dynamic deformation of the mirror surface.
[0049] In this embodiment, please refer to Figure 3 , Figure 4 and Figure 9, the reinforcement structure 70 includes a first straight segment 71 and a second straight segment 72 respectively provided on the back of the transition connection ends 52 of the two first rotating shaft structures 50, a third straight segment 73 and a fourth straight segment 74 provided on the opposite sides of the back of the mirror 30, and curved segments 75 respectively connecting between the opposite ends of the first straight segment 71 and the second straight segment 72 and the third straight segment 73 and the fourth straight segment 74. The lengths of the first straight segment 71 and the second straight segment 72 are slightly less than the length of the transition connection end 52 to increase the anti-deformation ability at the edge. The third straight segment 73 and the fourth straight segment 74 are arranged as close as possible to the opposite sides of the mirror 30. Optionally, the short-axis length of the mirror surface of the mirror 30 is b, and the distance between the axis of the third straight segment 73 and the axis of the first rotating shaft structure 50 is not less than 0.25b. Adjacent two straight segments are connected by a curved segment 75 to increase the anti-deformation ability at the connection of the mirror surface and the torsion beam, and obtain a more optimized effect of suppressing the maximum dynamic deformation at the connection of the mirror surface and the torsion beam and the dynamic deformation of the mirror surface.
[0050] Optionally, the curved segment 75 and the contour line of the mirror 30 are equidistant arcs. The third straight segment 73 and the fourth straight segment 74 are parallel to the long-axis direction of the mirror 30 and are symmetrically arranged with respect to the long axis of the mirror 30. The first straight segment 71 and the second straight segment 72 are parallel to the short-axis direction of the mirror 30 and are symmetrically arranged with respect to the short axis of the mirror 30. The first straight segment 71, the third straight segment 73, the second straight segment 72, and the fourth straight segment 74 are sequentially connected end to end through four curved segments 75 to form a closed loop. The reinforcement structure 70 is symmetric about the axis of the first rotating shaft structure 50 and symmetric about the axis of the second rotating shaft structure 40. The first straight segment 71 and the second straight segment 72 are respectively perpendicular to the axis of the first rotating shaft structure 50. Each curved segment 75 extends from the position of the corresponding transition connection end 52 to the position on the mirror surface of the mirror 30. The widths of the third straight segment 73 and the fourth straight segment 74 are equal to the width of the curved segment 75, and the widths of the first straight segment 71 and the second straight segment 72 are greater than or equal to the width of the curved segment 75. Designed in this way, please refer to Figure 10 , at the same torsion angle of the mirror 30 and the frequency of the MEMS mirror structure, the maximum dynamic deformation of the mirror surface is only 82.8 nm. Compared with the dynamic deformation of the mirror surface in the example, the dynamic deformation of the mirror surface is significantly suppressed, the difference in the dynamic deformation of the entire mirror surface is small, the utilization rate of the mirror surface is effectively improved, and the thickness of the mirror surface of the mirror 30 can be reduced. By the reinforcement structure 70, the structural strength of the mirror 30 is enhanced, the mass increase of the whole MEMS mirror structure is small, the moment of inertia of the mirror surface increases slightly, and a high-frequency vibration can be achieved without a very large torsional stiffness.
[0051] Generally speaking, the MEMS mirror structure provided by the embodiment of the present application at least has the following characteristics:
[0052] First, the first rotating shaft structure 50 adopts an axially symmetric folding beam, and the design of the decreasing widths of the central beam 511 and the extension beam 512 can not only improve the torsional stiffness of the beam to achieve high-frequency vibration, but also reduce the maximum stress on the beam and make the stress on the beam evenly distributed.
[0053] Second, a widened transition connection end 52 is provided at the connection between the mirror surface of the mirror 30 and the beam of the first rotating shaft structure 50, and a reinforcement structure 70 is added to the back of the mirror surface. A part of the reinforcement structure 70 is located on the transition connection end 52, which can greatly reduce the dynamic deformation of the mirror surface and effectively suppress the dynamic deformation at the connection between the mirror 30 and the rotating shaft structure.
[0054] Third, based on the design of the widened transition connection end 52 at the connection between the first rotating shaft structure 50 and the mirror 30 and the reinforcement structure 70 on the back of the mirror surface, the difference in dynamic deformation within the effective area of the mirror surface is smaller, which can improve the utilization rate of the mirror surface.
[0055] Optionally, on the other hand, an embodiment of the present application provides a MEMS micromirror integrated product, including the MEMS micromirror structure of any of the foregoing embodiments. The MEMS micromirror integrated product is a product that includes the MEMS micromirror structure and is widely used in different fields such as optical communication, laser projection, three-dimensional imaging, and lidar, and can be one of the following: an optical communication system, a lidar system, a laser projection system, and a three-dimensional imaging system.
[0056] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims
1. A MEMS micromirror structure, characterized in that: include: Reflector; A frame, used to carry the reflector, including a fixed structure and a movable frame; A first rotating shaft structure is used to connect the reflector and the movable frame, and supports the reflector to perform a torsional motion with the first rotating shaft structure as an axis; A second rotating shaft structure is used to connect the movable frame and the fixed structure, and supports the movable frame to drive the reflector to perform a torsional motion with the second rotating shaft structure as an axis; Wherein, the first rotating shaft structure includes a beam body and a transition connection end connected between the beam body and the reflector, the width of the transition connection end is not less than half of the minor axis length of the reflector, and the width of the beam body is not less than the width of the transition connection end; The reinforcement structure is located at the back of the reflector and the transition connection end, and the reinforcement structure is a closed structure formed by connecting a straight line segment and a curved line segment end to end.
2. The MEMS micromirror structure according to claim 1, characterized in that: The beam body includes a central beam and extension beams which are bent and extended from one end of the central beam away from the movable frame to opposite sides respectively. The beam body is symmetrically arranged relative to the central beam.
3. The MEMS micromirror structure according to claim 2, characterized in that: The width of the central beam is greater than the width of the extended beam; and / or, The number of the extended beams located on different sides of the central beam is one or more, and the widths of different extended beams are the same or different.
4. The MEMS micromirror structure according to claim 2, characterized in that: There are multiple extension beams on each side of the central beam, and the widths of the multiple extension beams on the same side of the central beam gradually decrease in a direction away from the central beam.
5. The MEMS micromirror structure according to claim 1, characterized in that: The short axis length of the reflector is b, and the calculation formula of the width W of the transition connection end is as follows: W = (0.3-0.5) * b; and / or, The major axis length of the reflector is a, and the length L of the transition connection end is calculated as follows: L = (0.1 ~ 0.2) * a / 2.
6. The MEMS micromirror structure according to claim 1, characterized in that: The second rotating shaft structure includes a first connecting end connected to the movable frame, a main beam portion extending inwardly from the first connecting end to form a plurality of parallel straight line segments, and a second connecting end connecting the main beam portion to a fixed structure; Among the plurality of straight line segments, the first connecting end, the second connecting end and one of the straight line segments are located on the axis of the second rotating shaft structure.
7. The MEMS micromirror structure according to claim 1, characterized in that: The reinforcement structure includes a portion corresponding to the transition connection end and a portion corresponding to the reflector, and the reinforcement structure is symmetrical with respect to the axis of the first rotating shaft structure and with respect to the axis of the second rotating shaft structure.
8. The MEMS micromirror structure according to claim 7, characterized in that: The reinforcement structure includes a first straight line segment and a second straight line segment respectively arranged on the back side of the transition connection end of the two first rotating shaft structures, a third straight line segment and a fourth straight line segment respectively arranged on the opposite sides of the back side of the reflector, and a curved line segment respectively connected to the opposite ends of the first straight line segment and the second straight line segment and between the third straight line segment and the fourth straight line segment.
9. The MEMS micromirror structure according to claim 8, characterized in that: The curved line segment and the contour line of the reflector are equidistant arcs; and / or, The short axis length of the reflector is b, and the distance between the axis of the third straight line segment and the axis of the first rotating shaft structure is not less than 0.25b.
10. A MEMS micromirror integrated product, characterized in that: A MEMS micromirror structure comprising any one of claims 1 to 9; The MEMS micromirror integrated product is one of the following: an optical communication system, a laser radar system, a laser projection system, and a three-dimensional imaging system.