LiDAR, rotating mirror structure and its installation and adjustment method

Abstract

An embodiment of the present invention provides a lidar, a rotating mirror structure and an installation and adjustment method thereof. The rotating mirror structure includes a rotating mirror bracket and an adjustable rotating mirror, which includes a mirror surface part, an angle adjustment part and a connection part that are fixedly connected. The angle adjustment part and the connection part are respectively located at both ends in the vertical direction of the mirror surface part. The mirror surface part is located on the side of the rotating mirror bracket. The angle adjustment part is fixed to the rotating mirror bracket, and the fixed position of the angle adjustment part can only be changed along the diameter direction of the end face of the rotating mirror bracket. The connection part is connected to the rotating mirror bracket, and the included angle between the mirror surface part and the rotation axis of the rotating mirror bracket can be changed around the connection point between the connection part and the rotating mirror bracket; a connecting piece fixedly connects the angle adjustment part and the rotating mirror bracket. The rotating mirror structure provided by the embodiment of the present invention can improve the installation accuracy of the rotating mirror structure, and further improve the measurement accuracy and ranging ability of the lidar.

Description

Technical Field

[0001] Embodiments of the present invention relate to the technical field of environmental perception, and particularly to a lidar, a rotating mirror structure and an alignment method thereof. Background Art

[0002] A lidar is an important sensor for perceiving surrounding information. When detecting the surrounding environment, in one way, a rotating mirror can be used to reflect laser to detect the space to be detected, and the scanned laser reflected by the space to be detected can be received. After processing, the surrounding environment information can be obtained.

[0003] Therefore, the accuracy of the rotating mirror structure of the lidar, especially the angular accuracy of the rotating mirror, has a direct impact on the measurement accuracy and ranging ability of the lidar. Accurate rotating mirror accuracy has become the main index of the performance of such lidars.

[0004] In order to fix the rotating mirror, the method of glue bonding can be adopted, that is, the reflecting mirror is pasted to the fixedly connected rotating mirror bracket by glue. This method not only has low efficiency and low reliability, but also requires determining the angle at one time during production, with poor accuracy and difficulty in adjustment when the angle changes subsequently. In addition, the method of fixedly connecting a metal rotating mirror can also be adopted. A metal rotating mirror is a rotating mirror in which the reflecting mirror and the rotating mirror bracket are integrally formed. It has relatively high machining accuracy, but the machining cost is relatively high, and affected by the assembly process, it is still difficult to ensure the accuracy after the metal rotating mirror is assembled.

[0005] Therefore, how to improve the assembly accuracy of the rotating mirror has become a technical problem to be solved urgently. Summary of the Invention

[0006] The technical problem solved by the embodiments of the present invention is to provide a rotating mirror structure to improve the assembly accuracy of the rotating mirror.

[0007] To solve the above problems, embodiments of the present invention provide a rotating mirror structure, including:

[0008] A rotating mirror bracket;

[0009] An adjustable rotating mirror, including a fixedly connected mirror surface portion, an angle adjustment portion and a connection portion. The angle adjustment portion and the connection portion are respectively located at both ends of the mirror surface portion in the vertical direction. The mirror surface portion is located on the side of the rotating mirror bracket. The angle adjustment portion is fixed to the rotating mirror bracket, and the fixed position of the angle adjustment portion can only be changed along the diameter direction of the end face of the rotating mirror bracket. The connection portion is connected to the rotating mirror bracket, and the included angle between the mirror surface portion and the rotation axis of the rotating mirror bracket can be changed around the connection point between the connection portion and the rotating mirror bracket;

[0010] A connecting member, fixedly connecting the angle adjustment portion and the rotating mirror bracket.

[0011] Optionally, the angle adjustment part is fixed to the end of the rotating mirror bracket.

[0012] Optionally, the rotating mirror bracket includes:

[0013] A rotating mirror bracket body;

[0014] An angle adjustment seat, fixed to one end of the rotating mirror bracket body, is provided with a threaded connection hole. The angle adjustment part of the rotating mirror bracket is provided with an eccentric adjustment hole. The connecting part includes a fixedly connected threaded connection part and an eccentric adjustment part. The central axis of the eccentric adjustment part is parallel to the central axis of the threaded connection part and has a predetermined distance. The eccentric adjustment part includes a smooth outer peripheral arc surface. The threaded connection part is threadedly connected to the threaded connection hole, and the eccentric adjustment part is matched with the eccentric adjustment hole.

[0015] Optionally, the shape of the eccentric adjustment part includes a cylinder, and there is a predetermined distance between the central axis of the cylinder and the central axis of the threaded connection part. The eccentric adjustment hole includes an oblong hole, and the minor axis of the oblong hole extends along the radial direction of the diameter of the rotating mirror bracket.

[0016] Optionally, the shape of the eccentric adjustment part includes a frustum of a cone, and the size of the cross-section of the frustum of the cone gradually increases in the direction from approaching the threaded connection part to departing from the threaded connection part. The eccentric adjustment hole includes an oblong hole, and the minor axis of the oblong hole extends along the radial direction of the diameter of the rotating mirror bracket.

[0017] Optionally, the rotating mirror bracket includes:

[0018] A rotating mirror bracket body;

[0019] An angle adjustment seat, fixed to one end of the rotating mirror bracket body, is provided with an oblong connection hole. The major axis of the oblong connection hole is parallel to the diameter of the rotating mirror bracket. The angle adjustment part is provided with a threaded hole. The connecting part includes a bolt and a nut. The bolt passes through the threaded hole and the oblong connection hole and is connected to the nut.

[0020] Optionally, the angle adjustment seat is further provided with a limiting groove, the threaded connection hole is opened on the bottom wall of the limiting groove, the angle adjustment part is arranged in the limiting groove, and in the tangential direction of the end face of the rotating mirror bracket, the size of the angle adjustment part is equal to the size of the limiting groove.

[0021] Optionally, the rotating mirror bracket further includes a fixed seat. The fixed seat and the angle adjustment seat are respectively located at both ends of the rotating mirror bracket body. The fixed seat is provided with a fixed groove, and the connecting part is inserted into the fixed groove;

[0022] The rotating mirror structure further includes:

[0023] An elastic fixing member is fixed to the fixing base and provides elastic pressure for the connecting portion in a direction perpendicular to the mirror surface portion.

[0024] Optionally, the elastic fixing member includes:

[0025] A leaf spring, including an elastically bent portion and an elastic fixing portion fixedly connected. The elastically bent portion is disposed in the fixing groove and abuts against the connecting portion, and the elastic fixing portion is fixed to the fixing base.

[0026] Optionally, the elastic fixing member includes:

[0027] A helical spring is fixed in the fixing groove, and two ends of the helical spring respectively abut against the connecting portion and the side wall of the fixing groove.

[0028] Optionally, the number of the adjustable turning mirrors is at least two.

[0029] Optionally, it further includes:

[0030] A fixed turning mirror, including a fixed connecting portion and a fixed mirror surface portion. The fixed connecting portion is located at an end of the fixed mirror surface portion. The fixed mirror surface portion is located at a side of the turning mirror bracket and is symmetrically arranged with the mirror surface portion about the turning mirror bracket. The fixed connecting portion is fixed to the turning mirror bracket;

[0031] An elastic support member, with two ends respectively fixedly connected to the fixed turning mirror and the adjustable turning mirror.

[0032] To solve the above problems, an embodiment of the present invention further provides a lidar, including:

[0033] A laser emitting device, adapted to emit detection laser;

[0034] A turning mirror structure as described in any one of the foregoing embodiments, adapted to receive the emitted detection laser and reflect it to the space to be detected, or receive the scanned laser reflected by the space to be detected and reflect it;

[0035] A laser receiving device, adapted to receive the scanned laser reflected by the turning mirror structure.

[0036] To solve the above problems, an embodiment of the present invention further provides an alignment method for a turning mirror structure. The turning mirror structure includes the turning mirror structure as described in any one of the foregoing embodiments, including:

[0037] Connect the connecting portion of the adjustable turning mirror to the turning mirror bracket;

[0038] Connect the angle adjustment part and the rotating mirror bracket by using the connecting piece, and adjust the included angle between the mirror surface part and the rotation axis of the rotating mirror bracket during the connection process until the included angle is equal to the target included angle.

[0039] Optionally, the rotating mirror structure includes a fixed rotating mirror bracket, including:

[0040] Before connecting the connecting part of the adjustable rotating mirror to the rotating mirror bracket, it includes: fixedly connecting the fixed connecting part of the fixed rotating mirror bracket to the rotating mirror bracket;

[0041] The step of connecting the angle adjustment part and the rotating mirror bracket by using the connecting piece and adjusting the included angle between the mirror surface part and the rotation axis of the rotating mirror bracket during the connection process until the included angle is equal to the target included angle includes:

[0042] Connect the angle adjustment part and the rotating mirror bracket by using the connecting piece, and adjust the included angle between the mirror surface part and the rotation axis of the rotating mirror bracket during the connection process until the included angle between the mirror surface part and the rotation axis of the rotating mirror bracket is equal to the included angle between the fixed mirror surface part and the rotation axis of the rotating mirror bracket. Compared with the prior art, the technical solution of the embodiment of the present invention has the following advantages:

[0043] The rotating mirror structure provided by the embodiment of the present invention includes a rotating mirror bracket, an adjustable rotating mirror and a connecting piece. The adjustable rotating mirror includes a fixedly connected mirror surface part, an angle adjustment part and a connecting part. The angle adjustment part and the connecting part are respectively located at both ends of the mirror surface part in the vertical direction. The mirror surface part is located on the side of the rotating mirror bracket. The angle adjustment part is fixed to the rotating mirror bracket, and the fixed position of the angle adjustment part can only be changed along the diameter direction of the end face of the rotating mirror bracket. The connecting part is connected to the rotating mirror bracket, and the included angle between the mirror surface part and the rotation axis of the rotating mirror bracket can be changed around the connection point of the connecting part and the rotating mirror bracket. In this way, for the rotating mirror structure provided by the embodiment of the present invention, due to the connection method between the connecting part and the rotating mirror bracket and the fixing method between the angle adjustment part and the rotating mirror bracket, when installing and adjusting the rotating mirror structure, first set the mirror surface part on the side of the rotating mirror bracket, connect the connecting part to the rotating mirror bracket, then connect the angle adjustment part to the rotating mirror bracket by using the connecting part, and during the connection process, by continuously changing the position of the angle adjustment part in the diameter direction of the end face of the rotating mirror bracket, adjust the included angle between the mirror surface part and the rotation axis of the rotating mirror bracket until the included angle between the mirror surface part and the rotation axis of the rotating mirror bracket meets the requirements, and fix the angle adjustment part. It can be seen that for the rotating mirror structure provided by the embodiment of the present invention, during the installation and adjustment process, the position and tilt state of the mirror surface part can meet the accuracy target requirements by continuously adjusting the fixed position, so that the installation accuracy of the rotating mirror structure can be improved, and further the measurement accuracy and ranging ability of the lidar can be improved.

[0044] In an alternative embodiment, for the rotating mirror structure provided by the embodiments of the present invention, the rotating mirror bracket includes a rotating mirror bracket body and an angle adjustment seat. The angle adjustment seat is fixed to one end of the rotating mirror bracket body and is provided with a threaded connection hole. An eccentric adjustment hole is provided in the angle adjustment part of the rotating mirror bracket. The connecting member includes a threaded connection part and an eccentric adjustment part that are fixedly connected. The center line of the eccentric adjustment part is parallel to the central axis of the threaded connection part and has a predetermined distance. The eccentric adjustment part includes a smooth outer peripheral arc surface. The threaded connection part is threadedly connected to the threaded connection hole, and the eccentric adjustment part cooperates with the eccentric adjustment hole. In this way, for the rotating mirror structure provided by the embodiments of the present invention, when adjusting and installing the rotating mirror structure, on the one hand, the connection between the connecting member and the rotating mirror bracket is realized through the connection between the threaded connection part of the connecting member and the threaded connection hole of the angle adjustment seat. Since the center line of the eccentric adjustment part is parallel but not coincident with the central axis of the threaded connection part, and the eccentric adjustment part has a smooth outer peripheral arc surface, as the connecting member rotates to change the position of the eccentric adjustment part of the connecting member relative to the eccentric adjustment hole, it can drive the angle adjustment part to move along the diameter direction of the end face of the rotating mirror bracket, causing the mirror surface part to swing around the connection point between the connecting part and the rotating mirror bracket, realizing the adjustment of the included angle between the mirror surface part and the rotation axis of the rotating mirror bracket. The adjustment method is simple, and the included angle between the mirror surface part and the rotation axis of the rotating mirror bracket can be measured at any time during rotation. And when the included angle between the mirror surface part and the rotation axis of the rotating mirror bracket meets the requirements, only by stopping the rotation can the required installation and adjustment state of the mirror surface part be obtained. The adjustment process is easy to control and the installation and adjustment accuracy is relatively high. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0046] Figure 1 It is a schematic structural diagram of the rotating mirror structure provided by the embodiments of the present invention;

[0047] Figure 2 It is a schematic structural diagram of the connecting member provided by the embodiments of the present invention;

[0048] Figure 3 is Figure 1 The three-dimensional structural diagram of the rotating mirror structure shown;

[0049] Figure 4 It is a schematic diagram of the connection state between the connecting member and the angle adjustment part provided by the embodiments of the present invention;

[0050] Figure 5 Another three-dimensional structural schematic diagram of the connecting member provided by the embodiment of the present invention;

[0051] Figure 6 Shows Figure 1 A structural schematic diagram of the connecting portion of the rotating mirror structure shown;

[0052] Figure 7 Another structural schematic diagram of the rotating mirror structure provided by the embodiment of the present invention;

[0053] Figure 8 Is Figure 7 A cross-sectional schematic diagram of the rotating mirror structure shown;

[0054] Figure 9 Is Figure 7 A structural schematic diagram of the adjustable rotating mirror and the fixed rotating mirror of the rotating mirror structure shown;

[0055] Figure 10 A flow schematic diagram of the alignment method of the rotating mirror structure provided by the embodiment of the present invention.

[0056] Among them, the numbers of each component are shown in the following table.

[0057] 1 Rotating mirror bracket 11 Angle adjustment base 111 Threaded connection hole 112 Limit groove 12 Fixed base 121 Fixed groove 13 Rotating mirror bracket body 2 Adjustable rotating mirror 21 Angle adjustment part 211 Eccentric adjustment hole 22 Mirror surface part 23 Connection part 3 Connector 31 Eccentric adjustment part 32 Threaded connection part 5 Elastic piece 51 Elastic bending part 52 Elastic fixing part 6 Bolt 7 Fixed rotating mirror 71 Fixed connection part 72 Fixed mirror surface part 8 Elastic support 9 Motor Detailed implementation manners

[0058] As can be seen from the background art, the alignment accuracy of the rotating mirror of the rotating mirror structure of the lidar is relatively low.

[0059] To improve the rationality and compactness of the space utilization of the lidar, the embodiment of the present invention provides a rotating mirror structure, including:

[0060] A rotating mirror bracket;

[0061] The rotating mirror bracket includes a mirror surface portion, an angle adjustment portion, and a connecting portion that are fixedly connected. The angle adjustment portion and the connecting portion are respectively located at both ends of the mirror surface portion in the vertical direction. The mirror surface portion is located on the side of the rotating mirror bracket. The angle adjustment portion is fixed to the rotating mirror bracket, and the fixed position of the angle adjustment portion can only be changed along the diameter direction of the end surface of the rotating mirror bracket. The connecting portion is connected to the rotating mirror bracket, and the included angle between the mirror surface portion and the rotation axis of the rotating mirror bracket can be changed around the connection point between the connecting portion and the rotating mirror bracket;

[0062] A connecting member, fixedly connecting the angle adjustment portion and the rotating mirror bracket.

[0063] Thus, in the rotating mirror structure provided by the embodiment of the present invention, due to the connection mode between the connection part and the rotating mirror bracket and the fixing mode between the angle adjustment part and the rotating mirror bracket, when assembling and adjusting the rotating mirror structure, first place the mirror surface part on the side of the rotating mirror bracket, connect the connection part with the rotating mirror bracket, then use the connection part to connect the angle adjustment part with the rotating mirror bracket, and during the connection process, by continuously changing the position of the angle adjustment part in the diameter direction of the end face of the rotating mirror bracket, adjust the included angle between the mirror surface part and the rotation axis of the rotating mirror bracket until the included angle between the mirror surface part and the rotation axis of the rotating mirror bracket meets the requirements, and then fix the angle adjustment part.

[0064] It can be seen that in the process of assembling and adjusting the rotating mirror structure provided by the embodiment of the present invention, by continuously adjusting the fixed position, the state of the mirror surface part can meet the accuracy target requirements, thereby improving the installation accuracy of the rotating mirror structure, and further improving the measurement accuracy and ranging ability of the lidar.

[0065] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0066] It should be noted that the orientation or positional relationship indicated in this specification is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of description and simplification of description, rather than indicating or implying that the device referred to must have a specific orientation and be constructed in a specific orientation. Therefore, it should not be construed as a limitation of the present invention.

[0067] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of the rotating mirror structure provided by the embodiment of the present invention.

[0068] As shown in the figure, the rotating mirror structure provided by the embodiment of the present invention includes a rotating mirror bracket 1, an adjustable rotating mirror 2, and a connecting member 3.

[0069] Among them, the rotating mirror bracket 1 can be connected to a motor 9 (shown in Figure 7 and Figure 8(in the middle) to connect, so that the motor 9 drives the rotating mirror bracket 1 to rotate. As a preferred embodiment, the rotating mirror bracket 1 may have a cylindrical cavity for accommodating the motor 9. The connecting member 3 connects the rotating mirror bracket 1 and the adjustable rotating mirror 2, so that when the motor drives the rotating mirror bracket 1 to rotate, the adjustable rotating mirror 2 is driven to rotate. The adjustable rotating mirror 2 includes a mirror surface portion 22, an angle adjustment portion 21 and a connecting portion 23 which are fixedly connected. The angle adjustment portion 21 and the connecting portion 22 are respectively located at both ends in the vertical direction of the mirror surface portion 22. The mirror surface portion 22 is located at the side of the rotating mirror bracket. The angle adjustment portion 21 is fixed to the rotating mirror bracket 1, and the fixing position of the angle adjustment portion 21 can only be changed along the diameter direction of the end face of the rotating mirror bracket 1. The connecting portion 23 is connected to the rotating mirror bracket 1, and the included angle between the mirror surface portion 22 and the rotation axis of the rotating mirror bracket 1 can be changed around the connection point between the connecting portion and the rotating mirror bracket 1. And the connecting member 3 fixedly connects the angle adjustment portion 21 and the rotating mirror bracket 1. Wherein, the rotation axis of the rotating mirror bracket 1 is the rotation axis of the motor 9. That is to say, the rotating mirror bracket 1 can rotate around the rotation axis of the motor 9.

[0070] It is easy to understand that the mirror surface portion 2 described herein is the plane portion in the rotating mirror structure for realizing the light reflection function. The mirror surface portion 2 can be the metal surface of a metal rotating mirror formed by integrally molding a reflecting mirror and a rotating mirror bracket, or a structure formed by a part of the reflecting mirror and the rotating mirror bracket obtained by pasting the reflecting mirror on the rotating mirror bracket. The rotating mirror bracket refers to the structure connecting the reflecting mirror (or the metal surface) and the rotating mirror bracket 1, including the aforementioned angle adjustment portion 21 and the connecting portion 23. That is, the adjustable rotating mirror 2 includes the mirror surface portion 22 and the rotating mirror bracket.

[0071] It should be noted that both ends in the vertical direction of the mirror surface portion 22 described herein refer to both ends of the mirror surface portion in the direction parallel to the rotation axis of the rotating mirror bracket 1 when the mirror surface portion 22 is located at the side of the rotating mirror bracket 1. The mirror surface portion 22 is connected to the rotating mirror bracket through the angle adjustment portion 21 and the connecting portion 23 respectively located at both ends thereof. The statement that the included angle between the mirror surface portion 22 and the rotation axis of the rotating mirror bracket 1 can be changed around the connection point between the connecting portion 23 and the rotating mirror bracket 1 means that the included angle between the mirror surface portion 22 and the rotation axis of the rotating mirror bracket 1 can be adjusted. As the connection position between the angle adjustment portion 21 and the rotating mirror bracket 1 changes, the mirror surface portion 22 can swing around the connection point between the connecting portion 23 and the rotating mirror bracket 1. Of course, when the connection position between the angle adjustment portion 21 and the rotating mirror bracket 1 is determined, the position of the mirror surface portion 22 is determined, and the included angle between the mirror surface portion 22 and the rotation axis of the rotating mirror bracket 1 remains unchanged. The statement that the fixing position of the angle adjustment portion 21 can only be changed along the diameter direction of the end face of the rotating mirror bracket 1 means that the angle adjustment portion 21 can only be conveniently moved along the diameter of the end face of the rotating mirror bracket 1, and its positions in the direction of the rotation axis of the rotating mirror bracket 1 and the circumferential direction cannot be changed.

[0072] In a specific embodiment, as Figure 1 shown, in order to facilitate the adjustment of the fixed position of the angle adjustment part 21 and the mirror support 1, and facilitate the fixed connection of the connecting member 3, the angle adjustment part 21 can be fixed to the end of the mirror support 1.

[0073] It is easy to understand that the end of the mirror support 1 refers to the part of the mirror support 1 that includes the end face. The angle adjustment part 21 being fixed to the end of the mirror support 1 means that the angle adjustment part 21 is in contact with the end face of the mirror support 1 and is fixed to the mirror support 1.

[0074] Of course, in other embodiments, the angle adjustment part 21 may not be fixed to the end face of the mirror support 1, but to the middle part of the mirror support 1.

[0075] In order to facilitate the reflection of the light beam by the mirror structure, in a specific embodiment, the number of adjustable mirrors 2 can be at least 2. In this way, during the rotation of the mirror structure, multiple adjustable mirrors can be used to achieve the reflection of the light beam and environmental detection.

[0076] In this way, for the mirror structure provided by the embodiment of the present invention, due to the connection method between the connecting member 3 and the mirror support 1 and the fixing method between the angle adjustment part 21 and the mirror support 1, when assembling and adjusting the mirror structure, first set the mirror surface part 22 on the side of the mirror support 1, connect the connecting part 23 with the mirror support, and then use the connecting member 3 to connect the angle adjustment part 21 and the mirror support 1. During the connection process, by continuously changing the position of the angle adjustment part 21 in the diameter direction of the end face of the mirror support 1, adjust the included angle between the mirror surface part 22 and the rotation axis of the mirror support 1 until the included angle between the mirror surface part 22 and the rotation axis of the mirror support 1 meets the requirements, and fix the angle adjustment part 21 to achieve the fixation of the mirror surface part 22 and the adjustable mirror 2.

[0077] It can be seen that for the mirror structure provided by the embodiment of the present invention, during the assembly and adjustment process, by continuously adjusting the fixed position of the angle adjustment part 21, the position and inclination state of the mirror surface part 22 can both meet the accuracy target requirements, thereby improving the installation accuracy of the mirror structure, and further improving the measurement accuracy and ranging ability of the lidar.

[0078] To further facilitate the connection between the angle adjustment part 21 and the mirror support 1, please refer to Figure 1 , and refer to Figure 2 and Figure 3 , where Figure 2 is a schematic structural diagram of a connecting member provided by the embodiment of the present invention; Figure 3 is Figure 1 a three-dimensional structural schematic diagram of the mirror structure shown in

[0079] As shown in the figure, the rotating mirror bracket 1 may include: a rotating mirror bracket body 13 and an angle adjustment base 11. Among them, the angle adjustment base 11 is fixed to one end of the rotating mirror bracket body 13. The angle adjustment base 11 is provided with a threaded connection hole (not shown in the figure). An eccentric adjustment hole 211 is provided in the angle adjustment portion 21 of the adjustable rotating mirror 2. The connecting member 3 includes a threaded connection portion 32 and an eccentric adjustment portion 31 that are fixedly connected. The center line of the eccentric adjustment portion 31 is parallel to the central axis of the threaded connection portion 32 and has a predetermined distance. The eccentric adjustment portion 31 includes a smooth outer peripheral arc surface. The threaded connection portion 32 is threadedly connected to the threaded connection hole 111 (shown in Figure 1 it), and the eccentric adjustment portion 31 cooperates with the eccentric adjustment hole.

[0080] Specifically, the smooth outer peripheral arc surface of the eccentric adjustment portion 31 may include various different arc surfaces such as a cylindrical surface, an elliptical surface, a conical surface, and an irregular arc surface, as long as eccentric adjustment can be achieved.

[0081] When the smooth outer peripheral arc surface of the eccentric adjustment portion 31 is a cylindrical surface, the eccentric adjustment portion 31 is a cylinder, but the center line of the cylinder is parallel to the central axis of the threaded connection portion 32 and does not coincide. Thus, when the connecting member 3 rotates around the threaded connection portion 32, the eccentric adjustment portion 31 can achieve the function of eccentric adjustment. That the smooth outer peripheral arc surface of the eccentric adjustment portion 31 is an elliptical surface means that the cross-section of the eccentric adjustment portion 31 is an ellipse, but the center line of the eccentric adjustment portion 31 passing through the center of the ellipse and parallel to the central axis of the threaded connection portion 32 does not coincide with the central axis of the threaded connection portion 32. That the smooth outer peripheral arc surface of the eccentric adjustment portion 31 is a conical surface means that the eccentric adjustment portion 31 is a frustum of a cone, but the center line of the frustum of the cone is parallel to the central axis of the threaded connection portion 32 and does not coincide.

[0082] The center line of the eccentric adjustment portion 31 is parallel to the central axis of the threaded connection portion 32 and has a predetermined distance, so as to ensure that the eccentric adjustment portion 31 can achieve eccentric adjustment when rotating in the eccentric adjustment hole 211.

[0083] The setting of the angle adjustment base 11 can more conveniently connect the angle adjustment portion 21 and the rotating mirror bracket 1.

[0084] It should be noted that the eccentric adjustment hole 211 only needs to be able to achieve the rotation and eccentric adjustment of the eccentric adjustment portion 31, and when the position is determined, it can ensure the stability of the connection.

[0085] In this way, when adjusting and aligning the rotating mirror structure provided by the embodiment of the present invention, on the one hand, the connection between the connecting member 3 and the rotating mirror bracket 1 is realized through the connection between the threaded connection portion 31 of the connecting member 3 and the threaded connection hole 111 of the angle adjustment seat 11. Since the center line of the eccentric adjustment portion 31 is parallel to but does not coincide with the central axis of the threaded connection portion 32, and the eccentric adjustment portion 31 has a smooth outer peripheral arc surface, as the connecting member 3 rotates, the position of the eccentric adjustment portion 31 of the connecting member 3 in the eccentric adjustment hole 211 changes. Due to the rotation requirement of the major diameter of the eccentric adjustment portion 31, the eccentric adjustment portion 31 will push the moving angle adjustment portion 21 to move along the diameter direction of the end face of the rotating mirror bracket 1, causing the mirror surface portion 22 to swing around the connection point between the connecting portion 23 and the rotating mirror bracket 1, thereby realizing the adjustment of the included angle between the mirror surface portion 22 and the rotation axis of the rotating mirror bracket 1.

[0086] It can be seen that in the setting method of the above structure, the adjustment process is simple, and the included angle between the mirror surface portion and the rotation axis of the rotating mirror bracket can be measured at any time during rotation. And when the included angle between the mirror surface portion and the rotation axis of the rotating mirror bracket meets the requirements, only by stopping the rotation can the required adjustment state of the mirror surface portion be obtained. The adjustment process is easy to control and the adjustment accuracy is relatively high.

[0087] In a specific embodiment, in order to reduce the processing difficulty of the eccentric adjustment portion 31, as Figure 2 and Figure 3 shown, the shape of the eccentric adjustment portion 31 includes a cylinder. As described above, there is a predetermined distance between the central axis of the cylinder and the axis of the threaded connection portion 31. The eccentric adjustment hole 211 includes an oblong hole, and the minor diameter of the oblong hole extends along the radial direction of the diameter of the rotating mirror bracket 1.

[0088] The eccentric adjustment portion 31 in the shape of a cylinder can be easily processed, and the oblong hole can provide enough space for the rotation of the eccentric adjustment portion 31. And the minor diameter of the oblong hole extends along the radial direction of the diameter of the rotating mirror bracket 1, so that the direction of eccentric adjustment is also along the radial direction of the diameter of the rotating mirror bracket 1, that is, the angle adjustment portion 21 is realized to move along the radial direction of the diameter of the rotating mirror bracket 1, and the inclination angle of the mirror surface portion 22 is adjusted, which can reduce the processing difficulty on the basis of ensuring the functional requirements.

[0089] In another specific embodiment, in the eccentric adjustment portion 31, the part that pushes the angle adjustment portion 21 to move is the part that contacts the side wall of the eccentric adjustment hole 211, that is, the far outer arc surface on the side farther from the axis of the threaded connection portion 32, while there may be a gap d between the near arc surface on the side closer to the axis of the threaded connection portion 32 and the side wall of the eccentric adjustment hole 211, as Figure 4 shown, Figure 4It is a schematic diagram of the connection state between the connecting member and the angle adjustment portion provided by the embodiment of the present invention. In this way, when vibrations occur during the use of the rotating mirror structure or the lidar, the position of the adjustable rotating mirror will change, affecting the installation accuracy of the rotating mirror structure and the detection accuracy of the lidar. Therefore, in order to ensure the firmness and stability of the connection of the connecting member 3 after the angle adjustment is completed, the embodiment of the present invention also provides a rotating mirror structure. Please refer to Figure 3 Reference Figure 5 , Figure 5 It is another three-dimensional structure schematic diagram of the connecting member provided by the embodiment of the present invention.

[0090] As shown in the figure, the shape of the eccentric adjustment portion 31 of the rotating mirror structure provided by the embodiment of the present invention includes a frustum of a cone, and the size of the cross-section of the frustum of the cone gradually increases in the direction from approaching the threaded connection portion 32 to moving away from the threaded connection portion 32. The eccentric adjustment hole 211 includes an oblong hole, and the minor axis of the oblong hole extends along the radial direction of the diameter 1 of the rotating mirror bracket.

[0091] In this way, as the connecting member 3 rotates, the size of the frustum of the cone gradually increases. Thus, when the connecting member 3 is adjusted to an appropriate position, the gap between the near arc surface of the eccentric adjustment portion 31 and the eccentric adjustment hole 211 is small or there is no gap, so as to prevent the angle between the mirror surface portion 22 and the rotation axis of the rotating mirror bracket 1 from changing under the influence of external forces. And preferably, an interference fit exists between the eccentric adjustment portion 31 and the eccentric adjustment hole 211. On the other hand, the size of the cross-section of the frustum of the cone gradually increases in the direction from approaching the threaded connection portion 32 to moving away from the threaded connection portion 32. Thus, in the direction along the rotation axis of the rotating mirror bracket 1, if the adjustable rotating mirror 2 is subjected to an external force and has a tendency to move away from the rotating mirror bracket 1, the frustum of the cone can also exert a restricting effect on the angle adjustment portion 21 of the adjustable rotating mirror 2 to prevent it from moving.

[0092] Of course, in addition to connecting the eccentric adjustment portion 31 to the angle adjustment seat 11 of the rotating mirror bracket 1 by means of threaded connection and opening the angle adjustment hole 211 on the angle adjustment portion 21 to realize the angle adjustment of the mirror surface portion 22, in another specific embodiment, other methods can also be adopted, which are not shown in the drawings. Specifically, the rotating mirror bracket 1 includes a rotating mirror bracket main body and an angle adjustment seat fixed to one end of the rotating mirror bracket main body. The angle adjustment seat is provided with an oblong connection hole, the major axis of the oblong connection hole is parallel to the diameter of the rotating mirror bracket, and the angle adjustment portion 21 is provided with a threaded hole. The connecting member includes a bolt and a nut, and the bolt passes through the threaded hole and the oblong connection hole and is connected to the nut.

[0093] In this way, when adjusting the mirror rotating structure, first place the mirror surface part 22 on the side of the mirror rotating bracket 1, connect the connecting part 23 to the mirror rotating bracket, then use a connecting piece to connect the angle adjusting part 21 to the mirror rotating bracket 1, and during the connection process, by continuously changing the position of the angle adjusting part 21 in the diameter direction of the end face of the mirror rotating bracket 1, adjust the included angle between the mirror surface part 22 and the rotation axis of the mirror rotating bracket 1 until the included angle between the mirror surface part 22 and the rotation axis of the mirror rotating bracket 1 meets the requirements. Pass the bolt of the connecting piece through the threaded hole and the oblong connecting hole and connect it to the nut, and use the nut and the bolt head to clamp the angle adjusting seat 11 of the mirror rotating bracket and the angle adjusting part 21 of the adjustable mirror to fix the relative position of the angle adjusting part 21 relative to the angle adjusting seat 11.

[0094] It can be seen that for the mirror rotating structure provided by the embodiment of the present invention, by using existing bolts and nuts and opening an oblong connecting hole on the angle adjusting seat 11 with the major axis parallel to the diameter of the mirror rotating bracket 1, the adjustment of the included angle between the mirror surface part 22 and the axis of the mirror rotating bracket 1 is realized, and the processing is simpler, so that on the basis of meeting the functional requirements, the cost is further reduced.

[0095] It is easy to understand that in other embodiments, the oblong connecting hole can also be opened on the angle adjusting part 21, and the threaded hole can be opened on the angle adjusting seat 11.

[0096] In order to facilitate the restriction of the angle adjusting part 21 in the circumferential direction of the mirror rotating bracket 1, in a specific embodiment, as Figure 1 shown, the angle adjusting seat 11 is further provided with a limiting groove 112, the threaded connection hole 111 is opened on the bottom wall of the limiting groove 112, the angle adjusting part 21 is arranged in the limiting groove 112, and in the tangential direction of the end face of the mirror rotating bracket 1, the size of the angle adjusting part 21 is equal to the size of the limiting groove 112, so that the restriction of the angle adjusting part 21 in the circumferential direction of the mirror rotating bracket can be conveniently realized.

[0097] Please refer to Figure 6 , Figure 6 shows Figure 1 a schematic structural diagram of the connecting part of the mirror rotating structure shown in

[0098] In order to facilitate the connection between the connecting part 23 and the mirror rotating bracket 1, in a specific embodiment, the mirror rotating bracket 1 of the mirror rotating structure provided by the embodiment of the present invention further includes a fixing seat 12 (shown in Figure 1In (China), the fixed seat 12 and the angle adjustment seat 11 are respectively located at both ends of the rotating mirror bracket main body 12. The fixed seat 12 is provided with a fixed groove 121, and the connecting portion 23 is inserted into the fixed groove 121. Correspondingly, the rotating mirror structure further includes: an elastic fixing member, fixed to the fixed seat 12, and providing elastic pressure for the connecting portion 23 in a direction perpendicular to the mirror surface portion 22.

[0099] Specifically, as shown in the figure, the elastic fixing member can be fixed to the fixed seat 12 by bolts 6. Of course, the elastic fixing member can also be fixed to the fixed seat 12 by other means.

[0100] In this way, no matter how the angle between the mirror surface portion 22 and the rotation axis of the rotating mirror bracket 1 changes, the elastic fixing member can always provide elastic pressure for the connecting portion 23, so as to ensure the connection between the connecting portion 23 and the rotating mirror bracket 1 on the basis of meeting the adjustment of the mirror surface portion 22.

[0101] Specifically, please continue to refer to Figure 6 , in a specific embodiment, the elastic fixing member includes:

[0102] A spring piece 5, including an elastically bent portion 51 and an elastic fixing portion 52 which are fixedly connected. The elastically bent portion 51 is arranged in the fixed groove 121 and abuts against the connecting portion 23, and the elastic fixing portion 52 is fixed to the fixed seat. It can be seen that the structure of the spring piece 5 is simple, easy to process, and convenient to be fixed to the fixed seat 12. It can not only reduce costs and facilitate installation, but also better meet the functional requirements.

[0103] In order to meet the connection requirements between the connecting portion 23 and the rotating mirror bracket 1, in another specific embodiment, the elastic fixing member may further include: a spiral spring (not shown in the figure), fixed in the fixed groove 121, and both ends of the spiral spring respectively abut against the connecting portion 23 and the side wall of the fixed groove 121.

[0104] Of course, the spiral spring can be fixed in various ways. For example, grooves can be opened on the side wall of the connecting portion 23 and the fixed groove 121, or both ends of the spiral spring can be respectively pasted on the side wall of the connecting portion 23 and the fixed groove 121, etc., which are all acceptable.

[0105] Please refer to Figures 7 - 9 , Figure 7 which is another structural schematic diagram of the rotating mirror structure provided by the embodiment of the present invention; Figure 8 is Figure 7 a schematic cross-sectional view of the rotating mirror structure shown in Figure 9 is Figure 7 a structural schematic diagram of the adjustable rotating mirror and the fixed rotating mirror of the rotating mirror structure shown in

[0106] As shown Figures 7 - 9 in the figure, the rotating mirror structure provided by the embodiment of the present invention further includes: a fixed rotating mirror 7 and an elastic support 8. The fixed rotating mirror 7 includes a fixed connection portion 71 and a fixed mirror surface portion 72. The fixed connection portion 71 is located at the end of the fixed mirror surface portion 72. The fixed mirror surface portion 72 is located on the side of the rotating mirror bracket 1 and is symmetrically arranged with the mirror surface portion 22 about the rotating mirror bracket 1. The fixed connection portion 71 is fixed to the rotating mirror bracket 1; the elastic support 8 is fixedly connected to the fixed rotating mirror 7 and the adjustable rotating mirror 2 at both ends respectively.

[0107] It should be noted that the statement that the fixed connection portion 71 is located at the end of the fixed mirror surface portion 72 in this article means that the fixed connection portion 71 is located at one end of the fixed mirror surface portion 72, and it can be connected to its end face or at a position a certain distance inward from its end face (as shown in the figure).

[0108] In one embodiment, the fixed mirror surface portion 72 of the fixed rotating mirror 7 and the mirror surface portion 22 of the adjustable rotating mirror 2 are respectively arranged on both sides of the rotating mirror bracket 1. When adjusting the rotating mirror structure, the fixed connection portion 71 is fixedly connected to the rotating mirror bracket 1, and then the angle adjustment portion 21 and the rotating mirror bracket 1 are connected by the connecting member 3. During the connection process, by continuously changing the position of the angle adjustment portion 21 in the diameter direction of the end face of the rotating mirror bracket 1, the included angle between the mirror surface portion 22 and the rotation axis of the rotating mirror bracket 1 is adjusted until the included angle between the mirror surface portion 22 and the rotation axis of the rotating mirror bracket 1 is the same as the included angle between the fixed mirror surface portion 72 and the rotation axis of the rotating mirror bracket 1, and the angle adjustment portion 21 is fixed to realize the fixation of the mirror surface portion 22 and the adjustable rotating mirror 2.

[0109] It can be seen that for the rotating mirror structure provided by the embodiment of the present invention, by adjusting the adjustable rotating mirror 2, the included angle between the mirror surface portion 22 of the adjustable rotating mirror 2 and the rotation axis of the rotating mirror bracket 1 can be made the same as the included angle between the fixed mirror surface portion 72 and the rotation axis of the rotating mirror bracket 1, improving the installation accuracy of the rotating mirror structure, and further improving the measurement accuracy and ranging ability of the lidar.

[0110] To solve the foregoing problems, the embodiment of the present invention further provides a lidar, including: a laser emitting device, the rotating mirror structure as described above, and a laser receiving device, wherein the laser emitting device is adapted to emit detection laser; the rotating mirror structure is adapted to receive the emitted detection laser and reflect it to the space to be detected, or receive the scanning laser reflected from the space to be detected and reflect it; the laser receiving device is adapted to receive the scanning laser reflected by the rotating mirror structure.

[0111] Since the rotating mirror structure includes an adjustable rotating mirror, during the alignment process, by continuously adjusting the fixed position of the angle adjustment part 21, the position and tilt state of the mirror surface part 22 can both meet the accuracy target requirements, thereby improving the installation accuracy of the rotating mirror structure, and further improving the measurement accuracy and ranging ability of the lidar.

[0112] To solve the foregoing problems, an embodiment of the present invention further provides an alignment method for a rotating mirror structure, which refers to Figure 10 , Figure 10 is a schematic flowchart of the alignment method for the rotating mirror structure provided by the embodiment of the present invention.

[0113] As shown in the figure, for the alignment method of the rotating mirror structure provided by the embodiment of the present invention, the rotating mirror structure includes the rotating mirror structure as described above, and the alignment method includes:

[0114] Step S1: Connect the connecting part of the adjustable rotating mirror 2 to the rotating mirror bracket 1;

[0115] Step S2: Use the connecting piece 3 to connect the angle adjustment part 21 and the rotating mirror bracket 1, and adjust the included angle between the mirror surface part 22 and the rotation axis of the rotating mirror bracket 1 during the connection process until the included angle is equal to the target included angle.

[0116] Specifically, for the alignment method of the rotating mirror structure provided by the embodiment of the present invention, the rotating mirror structure includes a fixed rotating mirror 72. Before the step of connecting the connecting part 23 of the adjustable rotating mirror to the rotating mirror bracket 1 in the alignment method, it includes: fixedly connecting the fixed connecting part 71 of the fixed rotating mirror bracket 7 to the rotating mirror bracket 1;

[0117] The step of using the connecting piece 3 to connect the angle adjustment part 21 and the rotating mirror bracket 1, and adjusting the included angle between the mirror surface part 22 and the rotation axis of the rotating mirror bracket 1 during the connection process until the included angle is equal to the target included angle includes:

[0118] Use the connecting piece 3 to connect the angle adjustment part 21 and the rotating mirror bracket 1, and adjust the included angle between the mirror surface part 22 and the rotation axis of the rotating mirror bracket 1 during the connection process until the included angle between the mirror surface part 22 and the rotation axis of the rotating mirror bracket 1 is equal to the included angle between the fixed mirror surface 72 and the rotation axis of the rotating mirror bracket 1.

[0119] The alignment method of the rotating mirror structure provided by the embodiment of the present invention can make the position and tilt state of the mirror surface part 22 both meet the accuracy target requirements, thereby improving the installation accuracy of the rotating mirror structure, and further improving the measurement accuracy and ranging ability of the lidar.

[0120] Although the embodiments of the present invention are disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. A rotating mirror structure, characterized in that, Comprising: A rotating mirror bracket, adapted to be connected to a motor, the rotating mirror bracket having a cylindrical cavity for accommodating the motor; The rotating mirror bracket includes: a rotating mirror bracket main body, an angle adjustment seat, and a fixed seat. The angle adjustment seat and the fixed seat are respectively located at both ends of the rotating mirror bracket main body, and the fixed seat is provided with a fixed groove; An adjustable rotating mirror, including a mirror surface portion, an angle adjustment portion, and a connection portion fixedly connected. The angle adjustment portion and the connection portion are respectively located at both ends in the vertical direction of the mirror surface portion. The mirror surface portion is located on the side of the rotating mirror bracket. The angle adjustment portion is fixed to the rotating mirror bracket, and the fixed position of the angle adjustment portion can only be changed along the diameter direction of the end face of the rotating mirror bracket. The connection portion is inserted into the fixed groove, and the angle between the mirror surface portion and the rotation axis of the rotating mirror bracket can be changed around the connection point between the connection portion and the rotating mirror bracket; The number of the adjustable rotating mirrors is at least 2, and the mirror surfaces of at least 2 adjustable rotating mirrors are respectively located on different sides of the rotating mirror bracket; An elastic fixing member, fixed to the fixed seat, and providing elastic pressure for the connection portion in a direction perpendicular to the mirror surface portion; A connecting member, fixedly connecting the angle adjustment portion and the rotating mirror bracket.

2. The rotating mirror structure according to claim 1, wherein The angle adjustment seat is provided with a threaded connection hole, the angle adjustment portion of the adjustable rotating mirror is provided with an eccentric adjustment hole, the connecting member includes a threaded connection portion and an eccentric adjustment portion fixedly connected. The central axis of the eccentric adjustment portion is parallel to the central axis of the threaded connection portion and has a predetermined distance. The eccentric adjustment portion includes a smooth outer peripheral arc surface. The threaded connection portion is threadedly connected to the threaded connection hole, and the eccentric adjustment portion is matched with the eccentric adjustment hole.

3. The rotating mirror structure according to claim 2, characterized in that, The shape of the eccentric adjustment portion includes a cylinder, and there is a predetermined distance between the central axis of the cylinder and the central axis of the threaded connection portion. The eccentric adjustment hole includes an oblong hole, and the short diameter of the oblong hole extends along the radial direction of the diameter of the rotating mirror bracket.

4. The rotating mirror structure according to claim 2, wherein, The shape of the eccentric adjustment portion includes a frustum of a cone, and the size of the cross section of the frustum of the cone gradually increases in a direction from approaching the threaded connection portion to departing from the threaded connection portion. The eccentric adjustment hole includes an oblong hole, and the short diameter of the oblong hole extends along the radial direction of the diameter of the rotating mirror bracket.

5. The rotating mirror structure according to claim 1, wherein The angle adjustment seat is provided with an oblong connection hole, the long diameter of the oblong connection hole is parallel to the diameter of the rotating mirror bracket, the angle adjustment portion is provided with a threaded hole, and the connecting member includes a bolt and a nut. The bolt passes through the threaded hole and the oblong connection hole and is connected to the nut.

6. The rotating mirror structure according to claim 2, wherein, The angle adjustment seat is further provided with a limiting groove, the threaded connection hole is opened on the bottom wall of the limiting groove, the angle adjustment portion is arranged in the limiting groove, and in the tangential direction of the end face of the rotating mirror bracket, the size of the angle adjustment portion is equal to the size of the limiting groove.

7. The rotating mirror structure according to claim 1, characterized in that, The elastic fixing member includes: The elastic piece includes an elastically bent portion and an elastically fixed portion which are fixedly connected. The elastically bent portion is disposed in the fixed groove and abuts against the connecting portion, and the elastically fixed portion is fixed to the fixed seat.

8. The rotating mirror structure according to claim 1, wherein The elastic fixing member includes: A spiral spring fixed in the fixed groove, and two ends of the spiral spring respectively abut against the connecting portion and the side wall of the fixed groove.

9. The rotating mirror structure according to any one of claims 1-6, characterized in that, It further includes: A fixed turning mirror, including a fixed connecting portion and a fixed mirror surface portion. The fixed connecting portion is located at the end of the fixed mirror surface portion. The fixed mirror surface portion is located at the side of the turning mirror bracket and is symmetrically arranged with the mirror surface portion with respect to the turning mirror bracket. The fixed connecting portion is fixed to the turning mirror bracket; An elastic support member, with two ends respectively fixedly connected to the fixed turning mirror and the adjustable turning mirror.

10. A lidar, characterized in that, It includes: A laser emitting device adapted to emit detection laser; The turning mirror structure according to any one of claims 1-9, adapted to receive the emitted detection laser and reflect it to the space to be detected, or receive the scanned laser reflected from the space to be detected and reflect it; A laser receiving device adapted to receive the scanned laser reflected by the turning mirror structure.

11. An alignment method for a rotating mirror structure, characterized in that, The turning mirror structure includes the turning mirror structure according to any one of claims 1-9, and includes: Connecting the connecting portion of the adjustable turning mirror to the turning mirror bracket; Using the connecting member to connect the angle adjusting portion and the turning mirror bracket, and adjusting the included angle between the mirror surface portion and the rotation axis of the turning mirror bracket during the connection process until the included angle is equal to the target included angle.

12. The alignment method of the rotating mirror structure according to claim 11, characterized in that, The turning mirror structure includes a fixed turning mirror and a fixed turning mirror bracket. The fixed turning mirror includes: a fixed connecting portion and a fixed mirror surface portion; Before connecting the connecting portion of the adjustable turning mirror to the turning mirror bracket, it includes: fixedly connecting the fixed connecting portion of the fixed turning mirror bracket to the turning mirror bracket; The step of using the connecting member to connect the angle adjusting portion and the turning mirror bracket and adjusting the included angle between the mirror surface portion and the rotation axis of the turning mirror bracket during the connection process until the included angle is equal to the target included angle includes: Using the connecting member to connect the angle adjusting portion and the turning mirror bracket, and adjusting the included angle between the mirror surface portion and the rotation axis of the turning mirror bracket during the connection process until the included angle between the mirror surface portion and the rotation axis of the turning mirror bracket is equal to the included angle between the fixed mirror surface portion and the rotation axis of the turning mirror bracket.

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