Spring assembly, scanning mirror and laser radar

Abstract

The invention discloses a spring assembly, a scanning mirror and a laser radar, and belongs to the technical field of machine manufacturing. The spring assembly comprises two torsion springs and a coupling spring arranged between the two torsion springs, the two ends of the coupling spring are connected with the two torsion springs respectively, and the coupling spring is stretched when the two torsion springs are twisted so as to provide nonlinear recovery torque. According to the technical scheme, the controllable nonlinear torsion spring and the implementation scheme of the scanning mirror and the laser radar based on the controllable nonlinear torsion spring can be achieved.

Description

Technical Field

[0001] This application belongs to the technical field of mechanical manufacturing, and particularly relates to a spring assembly, a scanning mirror, and a lidar. Background Art

[0002] A spring is a mechanical component commonly used in mechanical products. A simple spring can be a rod with one end fixed and the other end providing a restoring force during deformation. Similar simple springs are usually linear springs, that is, the restoring force of the spring is proportional to its deformation amount. The above deformation amount includes, but is not limited to, displacement and torsional angle, etc. However, in some application scenarios, non-linear springs are more preferred.

[0003] Micro-Electro-Mechanical System (hereinafter referred to as: MEMS) is a manufacturing technology platform developed based on semiconductor manufacturing technology. Springs also need to be fabricated in MEMS, but like springs in the ordinary mechanical field, they are usually linear springs. One application scenario of MEMS is to fabricate MEMS scanning mirrors. Usually, an MEMS scanning mirror consists of multiple micro-mirrors, and then by controlling the synchronous flipping of the multiple micro-mirrors, the effect of a larger area scanning mirror can be achieved. Among them, springs are used when controlling the flipping of the multiple micro-mirrors. In some related technologies, for example, US11085995B2 discloses that using non-linear springs can better synchronize the flipping of multiple micro-mirrors. However, in both the ordinary mechanical field and MEMS, it is difficult to obtain a suitable implementation scheme for non-linear springs. Summary of the Invention

[0004] This application aims to solve at least one of the technical problems existing in the prior art. For this reason, this application provides a spring assembly, a scanning mirror, and a lidar, which can realize a controllable non-linear torsion spring, as well as an implementation scheme of a scanning mirror and a lidar based on the controllable non-linear torsion spring.

[0005] In a first aspect, this application provides a spring assembly, including two torsion springs, and a coupling spring disposed between the two torsion springs. Both ends of the coupling spring are respectively connected to the two torsion springs and are stretched when the two torsion springs are twisted to provide a non-linear restoring torque. The spring assembly obtained by using this technical solution is equivalent to a controllable non-linear torsion spring.

[0006] In some embodiments, the connection manner between the torsion spring and the coupling spring can be that each torsion spring includes two relatively arranged fixed piles, and a first beam structure located between the fixed piles. A first connecting plate is provided on the first beam structure, and both ends of the coupling spring in the stretching direction are respectively connected to the first connecting plates of the two torsion springs.

[0007] In some embodiments, when the torsion spring is twisted, the first connecting plate rotates along the line connecting the two oppositely arranged fixed posts.

[0008] In some embodiments, the coupling spring may include a suspended second connecting plate. First openings are formed at both ends of the second connecting plate, and a second beam structure is formed within the first openings. The first connecting plate is connected to the second connecting plate through the second beam structure, thereby realizing the connection between the coupling spring and the torsion spring.

[0009] In some embodiments, a second opening is formed at one end of the first connecting plate close to the coupling spring. The coupling spring includes a connecting rod and connecting beams provided at both ends of the connecting rod. The connecting rod is connected to the first connecting plate on both sides of the second opening through the connecting beams, thereby realizing the connection between the coupling spring and the torsion spring. Moreover, this connection method is conducive to miniaturizing the size of the coupling spring and expanding the area of the torsion spring. Especially in the embodiment where a mirror is formed on the surface of the first connecting plate of the torsion spring, it can effectively expand the effective reflection area of the mirror.

[0010] In some embodiments, the above-mentioned connecting beam may include a first bending portion that protrudes in a direction away from the connecting rod. This design of the bent connecting beam can enable, when the connecting beam is subjected to a tensile force in a direction opposite to its protruding direction, even if a large displacement occurs, it is not easy for the tensile stress of the connecting beam to increase rapidly, thereby avoiding breaking the connecting beam after quickly reaching the fracture stress of silicon and providing its anti-breaking performance. At the same time, the first bending portion also causes its recovery coefficient to include a second-order non-linear recovery coefficient, which is conducive to ultimately realizing the controllable non-linearity of the spring assembly.

[0011] In some embodiments, a driving unit is further formed on the microelectromechanical system, and the driving unit is used to drive at least one of the two torsion springs to twist.

[0012] In some embodiments, each torsion spring is provided with a corresponding driving unit, and the driving unit is used to drive the corresponding torsion spring to twist.

[0013] In some embodiments, the driving unit is used to drive the two torsion springs to twist synchronously.

[0014] In a second aspect, the present application provides a scanning mirror, including torsion springs formed in an array on a microelectromechanical system. A coupling spring is provided between any two adjacent torsion springs. Both ends of the coupling spring are respectively connected to the two adjacent torsion springs and are stretched when the two adjacent torsion springs twist, so as to provide a non-linear restoring torque;

[0015] Each torsion spring includes two relatively arranged fixed posts and a beam structure located between the fixed posts. A first connecting plate is provided on the beam structure. The two ends in the stretching direction of the coupling spring are respectively connected to the first connecting plate of the torsion spring, and a mirror is formed on the surface of the first connecting plate.

[0016] In the embodiment of the present application, the mirror is formed on the first connecting plate of each torsion spring, so that each torsion spring is equivalent to a mirror. At this time, a plurality of small-area mirrors distributed in an array can form a large-area scanning mirror. The specific scanning function can be realized by the torsion spring. Since a coupling spring is provided between two adjacent torsion springs, that is, a plurality of spring assemblies connected to each other provided in the above embodiment have been formed, and each spring assembly is equivalent to a controllable nonlinear spring. At this time, other driving components can be used to drive the torsion spring to twist and drive the mirror to twist, and then use the nonlinear restoring force to restore, so as to periodically complete the above actions, so as to realize scanning the light emitted by all the mirrors within a set area, achieving the effect of an overall scanning mirror.

[0017] In some embodiments, an opening may be formed at one end of the first connecting plate of the torsion spring close to the coupling spring. The coupling spring includes a connecting rod and connecting beams provided at both ends of the connecting rod. The connecting rod is connected to the first connecting plates on both sides of the opening through the connecting beams. This implementation scheme is beneficial to miniaturize the size of the coupling spring and expand the area of the torsion spring, especially effectively expanding the effective reflection area of the mirror.

[0018] In some embodiments, the above connecting beam includes a first bending portion that protrudes in a direction away from the connecting rod. As described above, this design scheme of the bent connecting beam can make it difficult for the connecting beam to cause a rapid increase in tensile stress even when a large displacement occurs when the connecting beam is subjected to a tensile force in the opposite direction to its protruding direction, thereby avoiding breaking the connecting beam after quickly reaching the fracture stress of silicon and providing its anti-breaking performance. At the same time, the first bending portion will also cause its recovery coefficient to include a second-order nonlinear recovery coefficient, which is beneficial to finally realizing the controllable nonlinearity of the spring assembly.

[0019] In some embodiments, the scanning mirror further includes a driving component for driving the torsion springs distributed in an array to twist synchronously.

[0020] In some embodiments, the driving component includes a plurality of driving units, each driving unit is correspondingly arranged with a torsion spring and is used to drive the corresponding torsion spring to twist.

[0021] The scanning mirror provided by the embodiment of the present application, in which the torsion spring and the coupling spring can form the spring assembly in the above embodiment, and the design concept therein can also refer to the content in each embodiment of the spring assembly.

[0022] In a third aspect, the embodiment of the present application further provides a lidar, including a light source, a light detector, a processor, and the above scanning mirror. The laser beam emitted by the light source is reflected by the scanning mirror to the target area, and the light detector is configured to receive at least part of the reflected light from the target area and convert at least part of the reflected light into an electrical signal. The processor is configured to obtain the laser point cloud of the target area based on the electrical signal.

[0023] The scanning mirror provided by the embodiment of the present application, as well as the torsion spring and the coupling spring arranged in the scanning mirror, can both form the spring assembly in the above embodiment. The design concept and the corresponding technical effects therein can refer to the content recorded in each embodiment of the spring assembly and the scanning mirror above.

[0024] Some of the additional aspects and advantages of the present application will be given in the following description, some will become obvious from the following description, or will be understood through the practice of the present application. Description of the Drawings

[0025] The above and / or additional aspects and advantages of the present application will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, where:

[0026] Figure 1 It is a schematic structural diagram of a torsion spring in the related art;

[0027] Figure 2 It is a schematic diagram of a spring assembly in the embodiment of the present application;

[0028] Figure 3 For Figure 2 It is a schematic diagram when the torsion spring shown is twisted;

[0029] Figure 4 It is a schematic structural diagram of a spring assembly in the embodiment of the present application;

[0030] Figure 5 For Figure 4 It is a schematic structural diagram of a deformed spring assembly shown;

[0031] Figure 6 It is a schematic structural diagram of another spring assembly in the embodiment of the present application;

[0032] Figure 7 For Figure 6 It is a schematic structural diagram of a deformed spring assembly shown;

[0033] Figure 8 This is a schematic structural diagram of another spring component in the embodiments of the present application;

[0034] Figure 9 is Figure 8 a schematic structural diagram of a deformed structure of the spring component shown;

[0035] Figure 10 This is a schematic structural diagram of yet another spring component in the embodiments of the present application;

[0036] Figure 11 is Figure 10 a schematic structural diagram of a deformed structure of the spring component shown;

[0037] Figure 12 This is a schematic structural diagram of a scanning mirror in the embodiments of the present application;

[0038] Figure 13 This is a schematic structural diagram of a lidar in the embodiments of the present application. Detailed Description of the Embodiments

[0039] The embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described by referring to the drawings below are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application.

[0040] In the related art, most of the springs used are linear springs, that is, the recovery coefficient of the spring is mostly a first-order coefficient. Figure 1 This is a schematic structural diagram of a torsion spring in the related art. As Figure 1 described, the torsion spring includes two fixed posts 1, and a beam structure 2 is arranged between the two fixed posts 1. Optionally, a rigid plate 3 can be arranged on the beam structure 2 according to requirements. This torsion spring structure can be twisted around the connection line of the two fixed posts 1. Then, generally, its torsional restoring force is proportional to the torsional angle, that is, the torsional coefficient is a first-order linear coefficient. However, in some actual application scenarios, there is also a large demand for non-linear springs. For example, in the application scenario of a scanning mirror based on MSMS, a driving component is required to drive multiple small-area mirrors to twist simultaneously to achieve a mirror with a larger area. When driving multiple small-area mirrors to twist synchronously, using a non-linear spring to provide non-linear restoring force for each small-area mirror has a better synchronous effect. However, it is difficult to implement a non-linear spring on MEMS.

[0041] The embodiment of the present application provides a realization scheme of a controllable nonlinear spring. By adding a coupling spring between two torsion springs, both ends of the coupling spring are respectively connected to the two torsion springs above. When the two torsion springs are twisted, the coupling spring is stretched. At this time, the coupling spring can provide a tensile restoring force. When this tensile restoring force is applied to the two torsion springs, it can serve as the torsional restoring force of the torsion springs and provide a nonlinear restoring torque, so that the restoring coefficient of the entire spring assembly is finally changed, which is equivalent to obtaining a torsion spring with a nonlinear restoring coefficient.

[0042] Specifically, Figure 2 is a schematic diagram of a spring assembly in the embodiment of the present application, showing a specific scheme for realizing a nonlinear torsion spring using two torsion springs and a coupling spring. As Figure 2 shown, the spring assembly includes two torsion springs 11, and a coupling spring 12 is arranged between the two torsion springs 11. Both ends of the coupling spring 12 are respectively connected to the two torsion springs 11 above. When the two torsion springs 11 are twisted, the coupling spring 12 can be driven to be stretched simultaneously to provide a nonlinear restoring torque.

[0043] Figure 3 For Figure 2 the schematic diagram when the torsion spring is twisted in the shown embodiment, as Figure 3 shown, when the torsion angle of the torsion spring 11 is α during twisting, and the torsion angle of the coupling spring 12 is β. The distance from the center point of the torsion spring 11 to the connection point between it and the coupling spring 12 is called the length l of the torsion spring, and the distance from the center point of the coupling spring to the above connection point is called the length l c of the coupling spring. This length l c is the original length of the coupling spring. After the coupling spring 12 is stretched after the torsion spring 11 is twisted, the stretched length of the coupling spring 12 is l c ′, and the elongation of this process is Δl c . For Figure 3 the situation shown, if the length l c ′ of the stretched coupling spring 12 satisfies the following formula:

[0044]

[0045] Using the small-angle approximation, that is, sinα = α, the above formula can be simplified to:

[0046]

[0047] Ignoring the high-order terms in the above formula, the following result can be obtained:

[0048]

[0049] Perform a Taylor expansion on the above formula and retain the α 2 terms to obtain:

[0050]

[0051] Thus, it can be obtained that the elongation of the coupling spring 12 can be expressed as:

[0052]

[0053] At this time, the length of the torsion spring 11 can be defined as the ratio γ of l to the original length l c of the coupling spring 12 as:

[0054] γ = l / l c

[0055] Furthermore, the above formula for calculating Δl c can be simplified to:

[0056]

[0057] For the coupling spring 12, since it is stretched and elongated, it will provide a restoring force F along its length direction. If the stretching restoration coefficient of the coupling spring 12 is k, the restoring torque caused by the stretching and elongation of the coupling spring 12 can be expressed as:

[0058]

[0059] Thus, it can be seen that the restoring torque provided by the coupling spring 12 to the torsion spring 11 due to being stretched is non-linear, there is no linear term, and it is proportional to α 3 and proportional.

[0060] In the above embodiments of the present application, even if the coupling spring 12 is a linear spring, that is, the restoration coefficient k is a linear restoration coefficient, but when the coupling spring 12 is arranged between two torsion springs according to the method of the embodiments of the present application, the restoration coefficient of the obtained spring assembly is also non-linear, thus obtaining a torsion spring with a non-linear restoration coefficient.

[0061] In addition, if the above coupling spring 12 is a non-linear spring, that is, k is a non-linear restoration coefficient, the non-linear degree of the entire spring assembly will be more obvious. At the same time, by adjusting the length of the torsion spring 11, the length of the coupling spring 12, and the restoration coefficient of the coupling spring 12, for example, adjusting the values of parameters such as γ, k, or l, the non-linear degree of the spring assembly can be adjusted; if the coupling spring 12 itself is set to be non-linear, for example, the restoration coefficient includes a first-order non-linear term k 1, the second-order nonlinear term k 2 , the third-order nonlinear term k 3 … and so on. At this time, the restoring force F of the coupling spring can be set as:

[0062]

[0063] Through this solution, a spring assembly with higher-order nonlinear terms can be obtained.

[0064] In the embodiments of the present application, by setting the above parameters such as γ, k or l in the coupling spring, the adjustment of the nonlinear restoring coefficient of the spring assembly can be realized, and an adjustable nonlinear torsion spring can be obtained. The specific values of each parameter can be set according to actual needs.

[0065] The technical solution for realizing the adjustable nonlinear torsion spring provided by the embodiments of the present application does not limit the specific structure of the coupling spring, and it can also be designed according to different application fields and application scenarios, as long as it can meet the basic requirements in the above embodiments. For example, both ends of the coupling spring are respectively connected to the torsion spring, and at the same time, it can be stretched when the torsion spring is twisted, and a tensile restoring force is generated.

[0066] In some embodiments, the spring assemblies provided by the above various embodiments can be applied to the MEMS field. Specifically, it can be applied to an MEMS scanning mirror. At this time, two torsion springs 11 and a coupling spring 12 required by the spring assembly can be formed on the MEMS, and their relative positions and connection relationships all meet the limitations in the above various embodiments.

[0067] For the spring assembly provided on the MEMS system, its specific structure can be as Figure 4 and Figure 5 shown. For each torsion spring 11, it includes two relatively arranged fixed posts 21, and a first beam structure 22 located between the fixed posts 21, and a first connecting plate 23 is arranged on the first beam structure 22. Both ends of the coupling spring 12 in the stretching direction are respectively connected to the first connecting plates 23 of the above two torsion springs 11.

[0068] At this time, for the torsion spring 11, when the torsion spring 11 twists, the first connecting plate 23 will rotate along the connection line between the two relatively arranged fixed posts 21, and both ends of the coupling spring 12 are respectively connected to the first connecting plates 23 of the two torsion springs 11, so the coupling spring 12 will be stretched.

[0069] Regarding the specific structure of the coupling spring 12 and its connection relationship with the torsion spring 11, the embodiments of the present application do not make any limitations and provide two alternative implementation manners.

[0070] One implementation can be as follows Figure 4 As shown, the coupling spring 12 includes a suspended second connecting plate 31. Both ends of the second connecting plate 31 are formed with first openings 32, and a second beam structure 33 is formed within the first openings 32. The first connecting plate 23 is connected to the second connecting plate 31 through the second beam structure 33. The connection between the second beam structure 33 and the second connecting plate 31 also serves as a fixing post, so as to fix the first connecting plate 23 to the second connecting plate 31 through the second beam structure 33. In the above manner, both ends of the coupling spring 12 are connected to the torsion spring 11, and when the torsion spring 11 twists, the coupling spring 12 can be stretched, mainly the second beam structure 33 can be stretched.

[0071] Alternatively, in another implementation, it can also be as follows Figure 5 As shown, compared with Figure 4 where the second connecting plate 31 is free, in the embodiments of the present application, the above-mentioned fixing post 21 and the first beam structure 22 are further provided on the second connecting plate 31. For the spring assembly disposed on the MEMS system, the above-mentioned fixing post 21 can be disposed on the body of the MEMS system.

[0072] Another implementation can be as follows Figure 6 As shown, a second opening 24 is formed at one end of the first connecting plate 23 close to the coupling spring 12. The coupling spring 12 includes a connecting rod 34 and connecting beams 35 disposed at both ends of the connecting rod 34. The connecting rod 34 is connected to the first connecting plate 23 on both sides of the second opening 24 through the connecting beams 35. The connecting beams 35 in the embodiments of the present application can also be regarded as a kind of beam structure, and the connection between it and the first connecting plate 23 can be regarded as a fixing post for supporting the connecting beam 35. Since both ends of the connecting beam 35 are respectively connected to the first connecting plate 23, the connecting beam 35 can also be called a double-clamped beam.

[0073] Through Figure 6 The embodiments shown can connect the torsion spring 11 and the coupling spring 12, and the main structure of the coupling spring 12 in this embodiment can be regarded as composed of a connecting rod 34 and connecting beams 35 located at both ends of the connecting rod 34. The size of the above-mentioned main structure can be made smaller.

[0074] In addition, when the above structure on the MEMS is used as a MEMS scanning mirror, it can be realized by forming a mirror on the surface of the first connecting plate 23 of the torsion spring. Specifically, a reflective material can be coated on the surface of the first connecting plate 22 to form a mirror. In Figure 6In the illustrated embodiment, by making the size of the coupling spring 12 (connecting rod 34) smaller, more space can be reserved to accommodate the first connecting plate 23, so as to increase the area of the mirror on the first connecting plate 23 and improve the effective reflection area of the MEMS scanning mirror.

[0075] Alternatively, in another implementation, it can be as Figure 7 shown. Compared with Figure 6 where the connecting rod 34 is free, in the embodiment of the present application, the above-mentioned fixing posts 21 and the first beam structure 22 can be further provided on the connecting rod 34. For the spring assembly provided on the MEMS system, the above-mentioned fixing posts 21 can be provided on the body of the MEMS system.

[0076] In some embodiments, Figure 6 the shape of the connecting beam 35 in the shown coupling spring 12 can be designed to be bent, that is, the connecting beam 35 at least includes a first bending portion 36. Figure 8 This is a schematic structural diagram of a specific coupling spring in the embodiment of the present disclosure. As Figure 8 shown, the coupling spring includes a connecting rod 34 and connecting beams 35 at both ends of the connecting rod 34, and a first bending portion 36 is provided on the connecting beam 35.

[0077] Specifically, the first bending portion 36 can include various setting methods. For example, as Figure 8 shown, the first bending portion 36 is the whole of the entire connecting beam 35; or, in other setting methods, the first bending portion 36 can be set as a part of the connecting beam 35, and there are straight line segments or curve segments on both sides of the first bending portion 36, etc. However, no matter what setting method it is, since the first bending portion 36 is included, the T-shaped rod structure provided in the embodiment of the present application, due to the setting of the first bending portion 36, when a large displacement occurs under force in the direction opposite to the protruding direction of the first bending portion 36, it is not easy to cause the tensile stress of the connecting beam to increase rapidly, thereby avoiding the situation of breaking the connecting beam 35 after quickly reaching the fracture stress of silicon, thus improving its anti-breaking performance.

[0078] In addition, this design scheme with the first bending portion 36 can also increase the second-order non-linear term in the recovery coefficient of the coupling spring, so as to meet the requirements of some application scenarios. Specifically, as Figure 8 shown, for the left half of the connecting beam 35, that is, the shape of the section where 0 < x < L / 2, it can be described as:

[0079]

[0080] For the right half where L / 2 < x < L, it has a symmetric shape, where a 1, a 2 and a 3 are set constants, which are related to the initial shape of the connecting beam.

[0081] Thus, the relationship between the restoring force F and the deformation amount x can be derived as shown in the following formula:

[0082] F = kx + k 2 x 2 + k 3 x 3

[0083] Wherein,

[0084]

[0085]

[0086]

[0087] In the above formula, where E is the elastic modulus, I is the moment of inertia of the cross-section of the connecting beam, A is the cross-sectional area of the connecting beam, and L is the length of the connecting beam.

[0088] According to the relationship between the restoring force F and the deformation amount x above, it can be seen that the restoring coefficient therein includes a second-order non-linear term related to the shape of the connecting beam, and this second-order non-linear term indicates that the restoring force of the connecting beam 35 with the first bending portion 36 during deformation is asymmetric. The embodiment of the present application also realizes a controllable non-linear term.

[0089] Alternatively, in another implementation solution, it can be as Figure 9 shown. Compared with Figure 8 where the connecting rod 34 is free, in the embodiment of the present application, the above-mentioned fixing pile 21 and the first beam structure 22 can be further arranged on the connecting rod 34. For the spring assembly arranged on the MEMS system, the above-mentioned fixing pile 21 can be arranged on the body of the MEMS system.

[0090] In some embodiments, a driving unit can be arranged to drive the torsion spring to twist through this driving unit. Specifically, as Figure 10 shown, a driving unit 41 can also be formed on the MEMS, so that the driving unit 41 is used to drive at least one of the above two torsion springs 11 to twist. The driving unit 41 includes but is not limited to any one of an electrostatic driving unit, a thermoelectric driving unit, a capacitive driving unit, or a piezoelectric driving unit. By arranging any one of the above driving units 41 on the MEMS, the technical effect of driving the torsion spring 11 to twist can be achieved. Figure 10The setting position of the middle drive unit is only an example, and the appropriate setting position can be selected according to actual requirements and working modes.

[0091] In some embodiments, a corresponding drive unit 41 can be provided for each torsion spring 11, and each drive unit 41 is used to drive the corresponding torsion spring 11 to twist. The above drive unit 41 can drive the torsion spring 11 to twist at different times according to requirements, or the drive unit 41 drives two torsion springs 11 to twist synchronously. Especially in the application scenario of the above MEMS mirror, it is preferred that the drive unit 41 synchronously drives the torsion spring 11 to twist, so as to achieve that the small-area mirrors provided thereon can also flip synchronously, and further achieve the effect of forming a large-area scanning mirror by using small-area mirrors.

[0092] Or, in another implementation solution, it can be as Figure 11 shown. Compared with Figure 10 where the connecting rod 34 is free, in the embodiments of the present application, the above fixing pile 21 and the first beam structure 22 can be further provided on the connecting rod 34. For the spring assembly provided on the MEMS system, the above fixing pile 21 can be provided on the body of the MEMS system.

[0093] The embodiments of the present application also provide a scanning mirror, which is a scanning mirror based on the MEMS system and can be applied to lidar. Figure 12 This is a schematic structural diagram of the scanning mirror in the embodiments of the present application. As Figure 12 shown, the scanning mirror includes torsion springs 51 arranged in an array formed on a microelectromechanical system. A coupling spring 52 is provided between any two adjacent torsion springs 51. Both ends of the coupling spring 52 are respectively connected to the two adjacent torsion springs 51 and are stretched when the two adjacent torsion springs 51 twist, so as to provide a non-linear restoring torque;

[0094] Any two adjacent torsion springs 51 and the coupling spring 52 located in the middle thereof form a spring assembly, and specific reference can be made to the embodiments shown in the above Figures 2 - 11 shown.

[0095] In the embodiments of the present application, in combination with the above Figures 2 - 11 , for each torsion spring 51, it may include two relatively arranged fixing piles and a beam structure located between the fixing piles. A first connecting plate is provided on the beam structure. In addition, both ends in the stretching direction of the coupling spring 52 are respectively connected to the first connecting plates of the torsion springs, and a mirror is formed on the surface of the first connecting plate.

[0096] In the embodiments of the present application, multiple torsion springs 51 formed on the MEMS can be provided and are arranged in an array, that is, they can include multiple rows and columns of torsion springs 51, and a mirror is provided on the surface of the first connecting plate of each torsion spring 51, so that a large-area scanning mirror can be formed by the above-mentioned multiple small-area mirrors.

[0097] In some embodiments, as Figure 12 shown in the embodiments, a driving component can also be provided. The driving component is used to drive the torsion springs arranged in an array to twist synchronously. When the torsion springs arranged in an array twist synchronously, it is equivalent to driving a large-area scanning mirror to flip, so as to realize that the light reflected by it can be scanned within a set area.

[0098] In the embodiments of the present application, the working principle and the setting position of the driving component are not limited. It can include various forms of driving components. For example, it can be independently provided on the MEMS substrate, or can be provided on the MEMS substrate and the first connecting plate. And in order to save space and reserve space for the mirror on the first connecting plate, others can be integrally located below the first connecting plate.

[0099] In addition, the above-mentioned driving component can include multiple driving units. Each driving unit is correspondingly arranged with a torsion spring and is used to drive the corresponding torsion spring to twist. According to different working principles, the driving unit includes but is not limited to any one of an electrostatic driving unit, a thermal driving unit, a capacitive driving unit or a piezoelectric driving unit. By arranging any one of the above-mentioned driving units on the MEMS, the technical effect of driving the torsion spring to twist can be achieved. In some embodiments, in order to realize the effective connection between the coupling spring and the first connecting plate, an opening can be formed on the first connecting plate near one end of the coupling spring. The coupling spring includes a connecting rod and connecting beams provided at both ends of the connecting rod. The connecting rod is connected to the first connecting plate on both sides of the opening through the connecting beams. Specifically, reference can be made to the above Figure 6 shown in the embodiments. In other embodiments, it can also be that the coupling spring is provided with a second connecting plate, an opening and a beam structure are provided on the second connecting plate, and then the first connecting plate is connected to the first connecting plate through the beam structure. Specifically, reference can be made to the above Figure 4 shown in the embodiments. Compared with the technical solution of opening on the second connecting plate of the coupling spring, the technical solution of opening on the first connecting plate of the torsion spring can make the size of the coupling spring smaller and reserve more space to accommodate the first connecting plate, so as to increase the area of the mirror on the first connecting plate and improve the effective reflection area of the MEMS scanning mirror.

[0100] In addition, in some embodiments, in order to expand the area of each mirror and ultimately expand the area of the formed scanning mirror, the first connecting plate may be extended in the column direction so that the coupling spring is located in the gap formed by the first connecting plate. At this time, most of the area on the surface of the entire MEMS system is occupied by the finally formed scanning mirror, so as to further increase the effective reflection area of the MEMS scanning mirror and improve the uniformity of the reflected light.

[0101] Alternatively, further, for Figure 12 the torsion springs 51 on different columns in, they can be connected to the torsion springs 51 on the adjacent column and in the same row, that is, as in the Figures 4 - 11 illustrated embodiment, any first connecting plate 23 is connected to the first connecting plates 23 of other torsion springs 51 on the same row in the adjacent column, and only the fixed posts 21 need to be avoided. This implementation can further increase the area of the mirror on the first connecting plate 23, so as to further increase the effective reflection area of the MEMS scanning mirror and improve the uniformity of the reflected light.

[0102] In addition, in the embodiments of the present application, the connecting beam in the coupling spring includes a bending portion. For example, the first bending portion protrudes in a direction away from the connecting rod. Specifically, reference can be made to the Figure 8 illustrated embodiment. And due to the setting of the first bending portion, when a large displacement occurs in the direction opposite to the protruding direction of the first bending portion, it is not easy to cause the tensile stress of the connecting beam to increase rapidly, thereby avoiding breaking the connecting beam after quickly reaching the fracture stress of silicon, and providing its anti-breaking performance. In addition, this design can also increase the second-order non-linear term in the recovery coefficient of the coupling spring, and can better realize the controllable non-linear spring required by the technical solution of the present application, which is beneficial to subsequent synchronous control of the synchronous torsion of the above-mentioned multiple mirrors.

[0103] An embodiment of the present application also discloses a lidar, which can realize the functions of optical detection and ranging. Figure 13 is a schematic structural diagram of the lidar in the embodiment of the present application. As Figure 13 shown, in this lidar, it includes a light source 91, a light detector 92 and the above-mentioned scanning mirror 93. The laser beam emitted by the light source 91 is reflected by the above-mentioned scanning mirror 93 to the target area M, and the light detector 92 is configured to receive at least part of the reflected light in the target area M and convert at least part of the reflected light into an electrical signal. Further, a processor can be set. The processor can be configured to obtain the laser point cloud of the target area based on the electrical signal output by the light detector 92, and the functions of optical detection and ranging can be realized based on the above-mentioned laser point cloud. For the above-mentioned light source 91 and light detector 92 in this embodiment, they can also form a laser transceiver module to realize the emission and detection of laser.

[0104] In the lidar according to the embodiments of the present application, due to the use of the scanning mirror in the above embodiments, it also has corresponding technical effects and advantages. Moreover, the above lidar can be applied to vehicles. The solution in which the scanning mirror is composed of multiple small-area reflectors is more conducive to improving its anti-vibration ability during vehicle operation.

[0105] In addition, in the lidar according to the embodiments of the present application, by synchronously twisting each reflector in the scanning mirror, it is possible to reflect the laser beam to the target area M and then perform scanning. However, this scanning method is along a set direction. In order to expand the area of the target area M, it is also desired that it can perform scanning in the vertical direction. That is, for an XY coordinate system in the target area M, the technical solution of the embodiments of the present application can achieve scanning along the X axis, but cannot achieve scanning along the Y axis. Therefore, in some embodiments, a driving component can be added. The driving component can be set to directly drive the entire scanning mirror to reciprocate back and forth to achieve scanning along the Y axis. The above driving component can be a driving motor, and the driving motor directly uses the output shaft to drive the scanning mirror to reciprocate, so as to finally achieve the reflected light of the scanning mirror to scan along the Y axis. In this case, it is usually required that the output shaft of the driving motor can turn in time and switch between forward rotation and reverse rotation; alternatively, in an alternative technical solution, a motion adjustment part can be additionally added. The motion adjustment component can convert the continuous circular motion of the output shaft of the driving motor into a periodic reciprocating motion, and then the motion adjustment component drives the scanning mirror to perform periodic reciprocating motion, so as to finally achieve the reflected light of the scanning mirror to scan along the Y axis.

[0106] For the scanning mirror, the scanning frequency for driving each small-area reflector inside the scanning mirror provided by the above embodiments of the present application can be relatively high, that is, to achieve fast scanning along the X axis within the target area M; while the scanning frequency for driving the entire scanning mirror by the driving motor can be relatively low, that is, to achieve slow scanning along the Y axis within the target area M.

[0107] The terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects, rather than to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here. And the objects distinguished by "first", "second", etc. are usually of the same type, and do not limit the number of objects. For example, the first object can be one or multiple. In addition, "and / or" in the description and claims means at least one of the connected objects. The character " / ", generally represents an "or" relationship between the associated objects before and after.

[0108] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0109] In the description of the present application, the "first feature" and "second feature" may include one or more of such features.

[0110] In the description of the present application, the meaning of "a plurality" is two or more.

[0111] In the description of the present application, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through additional features therebetween.

[0112] In the description of the present application, the first feature being "above", "over" and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the horizontal height of the first feature is higher than that of the second feature.

[0113] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0114] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present application. The scope of the present application is defined by the claims and their equivalents.

Claims

1. A spring assembly, characterized in that: The invention comprises two torsion springs and a coupling spring arranged between the two torsion springs. Two ends of the coupling spring are respectively connected to the two torsion springs and are stretched when the two torsion springs are torsionally twisted to provide nonlinear restoring torque.

2. The spring assembly according to claim 1, characterized in that Each of the torsion springs comprises two oppositely arranged fixing piles and a first beam structure located between the fixing piles. A first connecting plate is arranged on the first beam structure. Both ends of the coupling spring in the stretched direction are respectively connected to the first connecting plates of the two torsion springs.

3. The spring assembly according to claim 2, characterized in that When the torsion spring is twisted, the first connecting plate rotates along the connecting line between the two oppositely arranged fixing piles.

4. The spring assembly according to claim 2, characterized in that The coupling spring includes a suspended second connecting plate, first openings are formed at both ends of the second connecting plate, a second beam structure is formed in the first opening, and the first connecting plate is connected to the second connecting plate through the second beam structure.

5. The spring assembly according to claim 2, characterized in that: A second opening is formed on one end of the first connecting plate close to the coupling spring. The coupling spring comprises a connecting rod (34) and connecting beams (35) arranged at both ends of the connecting rod. Each end of the connecting rod is connected to the first connecting plates at both sides of the second opening via the connecting beams.

6. The spring assembly according to claim 5, characterized in that The connecting beam includes a first curved portion that protrudes in a direction away from the connecting rod.

7. The spring assembly according to any one of claims 1 to 6, characterized in that: The device further comprises a driving unit, wherein the driving unit is used to drive at least one of the two torsion springs to torsion.

8. The spring assembly according to claim 7, characterized in that Each torsion spring is provided with a corresponding driving unit, and the driving unit is used to drive the corresponding torsion spring to twist.

9. A scanning mirror, characterized in that: include: A spring assembly, wherein the spring assembly is the spring assembly according to any one of claims 2 to 8, and a reflector is provided on the surface of the first connecting plate.

10. The scanning mirror according to claim 9, characterized in that The spring components are multiple and distributed in an array.

11. The scanning mirror according to claim 9, characterized in that: The surface of the first connecting plate is coated with a reflective material to form the reflector.

12. A laser radar, comprising a light source, a light detector, a processor and a scanning mirror according to any one of claims 9 to 11, wherein the laser beam emitted by the light source is reflected to a target area by the scanning mirror, and the light detector is configured to receive at least part of the reflected light from the target area and convert the at least part of the reflected light into an electrical signal, and the processor is configured to obtain a laser point cloud of the target area based on the electrical signal.

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