A scanning galvanometer driving device with compressed overall height dimension

Abstract

This invention relates to the field of scanning galvanometer technology, specifically to a scanning galvanometer driving device with compressed overall height dimensions. It includes a galvanometer chip, a magnetic drive assembly, and a support structure. The galvanometer chip includes a mirror, an anchoring structure, a torsion beam, and a movable frame with a metal coil. The torsion beam includes a pair of fast-axis beams and a pair of slow-axis beams. The magnetic drive assembly includes a magnet assembly and a magnetic guide assembly, which work together to provide at least one driving magnetic field. The magnet assembly in one direction is located below the galvanometer chip, and the magnetic guide assembly guides the distribution of magnetic field lines while also serving as a chip support structure and housing, without occupying additional space. Therefore, this application provides a strong magnetic field strength over a large space while compressing the overall height dimensions of the electromagnetic galvanometer to the limit, achieving the technical effect of reducing the overall size of the lidar device and helping to enhance the market competitiveness of lidar.

Description

Technical Field

[0001] This invention relates to the field of scanning galvanometer technology, and in particular to a scanning galvanometer driving device with a compressed overall height dimension. Background Technology

[0002] The scanning galvanometer is a core component of LiDAR, primarily used to scan the emitted beam. With the rapid development of the automotive LiDAR market, LiDAR demands larger mirror surfaces and wider scanning angles for scanning galvanometers to achieve greater detection distances and higher angular resolution. Based on the electromagnetic drive principle, the scanning galvanometer is driven by a current-carrying coil in a constant magnetic field under the Lorentz force, causing the mirror surface to rotate around a torsion beam. Compared to other driving methods such as electrostatic, electrothermal, and piezoelectric methods, it has advantages such as strong driving force and large torsion angle, making it particularly suitable for driving large-sized mirror surfaces.

[0003] In the prior art, the electromagnetic drive structure of the scanning galvanometer is as follows: Figures 1-2 As shown, Figure 1 The structure shown uses horizontally magnetized magnets, all located outside the coil. Furthermore, the scanning mirror must be positioned at the midpoint of the magnet's height to obtain a strong and uniform driving magnetic field. Therefore, the overall assembly structure is relatively large. Figure 2 The structure shown uses two sets of magnets with opposite upper and lower magnetic poles to drive the coil. The magnets are also located outside the coil. Therefore, not only is the overall volume large, but the huge repulsive force generated by the opposite upper and lower magnetic poles also makes assembly difficult.

[0004] Figure 3 This illustrates the application of lidar based on a two-dimensional scanning galvanometer in an automotive system, such as... Figure 3 As shown, it consists of a laser, a reflector, a scanning galvanometer, and a detector. The scanning galvanometer is generally placed vertically in the center of the lidar. Therefore, the size of the scanning galvanometer's housing is directly proportional to the overall size of the lidar. To further reduce the overall size of the lidar, it is necessary to further reduce the overall size of the large-size two-dimensional scanning galvanometer, especially the height dimension. The height dimension of the two-dimensional scanning galvanometer corresponds exactly to the slow axis scanning angle of the galvanometer, and it generally operates in a non-resonant mode, thus requiring a larger driving magnetic field strength. Summary of the Invention

[0005] The purpose of this invention is to provide a scanning galvanometer driving device with a compressed overall height, so as to meet the requirements of the magnetic driving device of the scanning galvanometer to provide a strong magnetic field strength in a large space and to be compact in size.

[0006] To achieve the above objectives, the present invention provides a scanning galvanometer driving device with a compressed overall height dimension, characterized in that,

[0007] It includes a galvanometer chip and a magnetic drive assembly. The galvanometer chip is disposed between the magnetic drive assembly and fixed on the support structure. The galvanometer chip includes a mirror, an anchoring structure, a torsion beam, and a movable frame with a metal coil.

[0008] The magnetic drive assembly includes a magnet assembly and a magnetic guide assembly. At least one magnet assembly consists of two magnets that are horizontally magnetized, have parallel magnetic surfaces, and have opposite magnetic poles. The magnet assembly is located below the galvanometer chip and works with the magnetic guide assembly to guide the driving magnetic field to the metal coil above.

[0009] The torsion beam includes a pair of fast-axis beams and a pair of slow-axis beams. The magnet assembly includes a first magnet group and a second magnet group. The first magnet group is located on both sides of the fast-axis drive side of the movable frame to provide a first driving magnetic field to drive the mirror to rotate about the coaxial line of the two fast-axis beams. The second magnet group is located below the slow-axis drive side of the movable frame and, in conjunction with the magnetic guiding structure, provides a second driving magnetic field to drive the movable frame and the mirror to rotate about the coaxial line of the two slow-axis beams.

[0010] The magnetic drive assembly provides a driving magnetic field for the metal coil. When the magnet assembly provides the magnetic field, the magnetic field lines enter the magnetic guide assembly and are conducted along the shape of the magnetic guide assembly, forming a closed loop in the magnet assembly, the magnetic guide assembly, and the air gap. This ensures that the movable frame has a strong driving magnetic field strength within a large range of motion. After the galvanometer chip is fixed by the anchoring structure and the magnet assembly provides two driving magnetic fields, the metal coil of the movable frame is energized. Driven by the Lorentz force, the mirror rotates around the coaxial axis of the two fast axis beams, generally performing resonant motion. The movable frame and the mirror will rotate together around the coaxial axis of the two slow axis beams, generally performing non-resonant motion, thus realizing the dual-axis scanning of the galvanometer chip.

[0011] The magnetic conductive assembly includes a first magnetic conductive structure and a second magnetic conductive structure. The first magnetic conductive structure is disposed on the inner side below the metal coil, and the height of the second magnetic conductive structure is higher than that of the metal coil. The first magnetic conductive structure and the second magnetic conductive structure are mounted on both sides of the magnet of the second magnet group, and the height of the first magnetic conductive structure and the second magnetic conductive structure is higher than that of the second magnet group.

[0012] The scanning galvanometer device with compressed overall height also includes a housing structure. The housing structure includes a base, an outer shell, a base, a first cover plate, and a second cover plate. The base cooperates with the first magnetically conductive structure to fix and support the galvanometer chip. The outer shell, the base, and the base are all made of non-magnetically conductive materials. The outer shell fits into the second magnetically conductive structure. The first cover plate and the second cover plate are disposed on the upper side of the magnet assembly.

[0013] The first magnet group can be composed of two rectangular magnets that are horizontally magnetized, have parallel magnetic surfaces, and have opposite magnetic poles, or it can be composed of two sets of upper and lower magnet groups that are vertically magnetized, have opposite magnetic poles, and are located on the upper and lower sides of the galvanometer chip, respectively, to provide a driving magnetic field on the non-compressed height side of the scanning galvanometer driving device that compresses the overall height dimension.

[0014] The galvanometer chip includes only a pair of torsion beams, and the magnet assembly includes only a pair of magnet groups and a magnetic guiding structure. The magnet group is located below the driving edge of the movable frame of the galvanometer chip and consists of a pair of horizontally magnetized first and second magnets, which drive the galvanometer chip to rotate around the axis of the torsion beams.

[0015] The magnet assembly includes two first magnetic conductive structures and two second magnetic conductive structures. The first magnetic conductive structures are located on the right side of the first magnet and the left side of the second magnet, respectively. The second magnetic conductive structures are located on the left side of the first magnet and the right side of the second magnet, respectively. The first magnetic conductive structures are also used to support and fix the galvanometer chip, and the second magnetic conductive structures are also used as the housing shell.

[0016] For ease of illustration, the full structure of the galvanometer chip is not shown in this application.

[0017] The first magnetically conductive structure, in conjunction with the base, provides a certain degree of support for the galvanometer chip and is at least 1 mm higher than the second magnet assembly. The galvanometer chip is fixed to the support structure by the anchoring structure. The second magnetically conductive structure and the outer shell are both located on the outside of the galvanometer chip, thereby compressing the height of the entire scanning galvanometer along the coaxial direction of the two fast-axis beams to the limit. The first cover plate and the second cover plate are used to fix the electrical connection device in the overall structure and provide a certain degree of protection.

[0018] The movable frame is square, circular, elliptical, or polygonal in shape; the torsion beam has at least one of straight beam, ring beam, and folded beam structure; and the mirror is square, circular, elliptical, rectangular, or polygonal in shape.

[0019] In this application, the structures of the components shown in the accompanying drawings are merely illustrative examples and should not be construed as limiting the scope of protection of this application.

[0020] This invention discloses a scanning galvanometer driving device with compressed overall height. A horizontally magnetized magnet is placed below a metal coil, and a magnetically conductive component made of magnetically conductive material guides the magnetic field to the desired spatial position, providing a strong magnetic field intensity over a large spatial range. Simultaneously, the magnetically conductive component supports the galvanometer chip and its packaging housing without occupying additional space. Therefore, this application provides a strong magnetic field intensity over a large spatial range while compressing the overall height of the electromagnetic galvanometer to its limit, achieving the technical effect of reducing the overall size of the lidar device and contributing to enhancing the market competitiveness of lidar. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 The present invention provides an electromagnetic drive structure for a scanning galvanometer using a horizontally magnetized magnet, which is a prior art technology.

[0023] Figure 2 The present invention provides an electromagnetic drive structure for two sets of magnet drive coils with opposite upper and lower magnetic poles of a scanning galvanometer.

[0024] Figure 3 This invention provides the basic structure of a prior art lidar based on a two-dimensional scanning galvanometer in a vehicle system.

[0025] Figure 4 This invention relates to the structure of a galvanometer chip in a scanning galvanometer driving device with a compressed overall height dimension, as provided by the prior art.

[0026] Figure 5 This invention provides the structure of a magnetic drive assembly for a scanning galvanometer drive device with a compressed overall height dimension, based on existing technology.

[0027] Figure 6 The magnetic drive assembly of a scanning galvanometer drive device with compressed overall height dimensions provided by the present invention is shown in the cross-sectional view along a plane perpendicular to the galvanometer plane and parallel to AA'.

[0028] Figure 7 This is a magnetic field distribution diagram of the magnetic conductive component of a scanning galvanometer driving device with a compressed overall height dimension, provided by the present invention.

[0029] Figure 8 This is a top view of a scanning galvanometer product of a prior art scanning galvanometer driving device with compressed overall height dimensions provided by the present invention.

[0030] Figure 9 This is an external structural diagram of a scanning galvanometer product of a prior art scanning galvanometer driving device with compressed overall height dimensions, provided by the present invention.

[0031] Figure 10 This is an exploded view of a scanning galvanometer product of a scanning galvanometer driving device with compressed overall height dimensions, provided by the present invention.

[0032] Figure 11 This is a structural diagram of a second embodiment of a scanning galvanometer driving device with compressed overall height dimensions provided by the present invention.

[0033] Figure 12 This is a cross-sectional view along the AA' direction of a second embodiment of a scanning galvanometer driving device with compressed overall height dimensions provided by the present invention.

[0034] Figure 13 This is a structural diagram of a third embodiment of a scanning galvanometer driving device with compressed overall height dimensions provided by the present invention.

[0035] Figure 14 This is a schematic diagram of a single-axis scanning galvanometer, representing a third embodiment of a scanning galvanometer driving device with compressed overall height dimensions provided by the present invention.

[0036] 31-Mirror surface, 32-Anchoring structure, 33-Modible frame, 34-Torsion beam, 331-Metal coil, 341-Fast axis beam, 342-Slow axis beam, 343-Connecting beam, 1-First magnet group, 11-Upper magnet, 12-Lower magnet, 2-Second magnet group, 41-First magnetic conductive structure, 42-Base, 51-Second magnetic conductive structure, 52-Outer shell, 53-Base, 61-First cover plate, 62-Second cover plate. Detailed Implementation

[0037] Please see Figures 4 to 10 The present invention provides a scanning galvanometer driving device with compressed overall height dimension, characterized in that,

[0038] The device includes a galvanometer chip, a magnetic drive assembly, and a housing structure. The galvanometer chip is fixed to the support structure. The magnetic drive assembly provides two driving magnetic fields. The galvanometer chip includes a mirror 31, an anchoring structure 32, a torsion beam 34, and a movable frame 33 with a metal coil 331. The anchoring structure 32 fixes the chip to the support structure. The torsion beam 34 includes a pair of fast-axis beams 341 and a pair of slow-axis beams 342. The two fast-axis beams 341 are coaxially mirror-arranged, with one end connected to the movable frame 33 and the other end connected to the mirror 31. The two slow-axis beams 342 are also coaxially mirror-arranged, with one end connected to the movable frame 33 and the other end connected to the anchoring structure 32. The metal coil 331 is disposed on the movable frame 33.

[0039] The magnetic drive assembly includes a magnet assembly and a magnetic guide assembly. The magnet assembly provides two driving magnetic fields. The two driving magnetic fields, together with the metal coil 331 and the magnetic guide assembly, enable the dual-axis scanning of the mirror 31. The dual-axis scanning of the mirror 31 specifically includes the rotation of the mirror 31 around the coaxial axis of the paired fast axis beams 341, and the rotation of the mirror 31 and the movable frame 33 together around the coaxial axis of the slow axis beam 342.

[0040] The magnetic drive assembly provides a driving magnetic field for the metal coil 331. When the magnet assembly provides the magnetic field, the magnetic field lines enter the magnetic guide assembly and are conducted along the shape of the magnetic guide assembly, forming a closed loop in the magnet assembly, the magnetic guide assembly and the air gap. This ensures that the movable frame 33 has a strong driving magnetic field strength within a large range of motion. After the magnet assembly provides two driving magnetic fields, the metal coil 331 of the movable frame 33 is energized. Driven by the Lorentz force, the mirror 31 rotates around the coaxial axis of the two fast axis beams 341, generally performing resonant motion. The movable frame 33 and the mirror 31 will rotate together around the coaxial axis of the two slow axis beams 342, generally performing non-resonant motion.

[0041] The magnet assembly includes a first magnet group 1 and a second magnet group 2. Both the first magnet group 1 and the second magnet group 2 consist of two rectangular magnets that are horizontally magnetized, have parallel magnetic surfaces, and opposite magnetic poles. The first magnet group 1 is located at both ends of the axis of the two slow axis beams 342 to provide a first driving magnetic field to drive the mirror 31 to rotate about the coaxial axis of the two fast axis beams 341. The second magnet group 2 is located at both ends of the axis of the two fast axis beams 341 to provide a second driving magnetic field to drive the movable frame 33 and the mirror 31 to rotate about the coaxial axis of the two slow axis beams 342.

[0042] Each magnet group consists of two rectangular magnets that are horizontally magnetized, have parallel magnetic surfaces, and opposite magnetic poles. The first magnet group 1 is located on both sides of the slow-axis beam 342 of the movable frame 33, and is used to provide the first driving magnetic field. The second magnet group 2 is located below the slow-axis driving edge of the frame, and is used to provide the second driving magnetic field. Since the second magnet group 2 cannot provide a sufficiently large driving magnetic field due to its location below the coil, the magnetic guiding component is used to guide the horizontal magnetic field to the metal coil 331. The coaxial line of the two fast-axis beams 341 is shown as AA' in the figure, and the coaxial line of the two slow-axis beams 342 is shown as BB' in the figure. In the figure, B2 is the second driving magnetic field, and B1 is the first driving magnetic field.

[0043] The magnetically conductive assembly includes a first magnetically conductive structure 41 and a second magnetically conductive structure 51. The first magnetically conductive structure 41 is disposed on the inner side below the metal coil 331, and the height of the second magnetically conductive structure 51 is higher than that of the metal coil 331. The first magnetically conductive structure 41 and the second magnetically conductive structure 51 are mounted on the outer side of the second magnet group 2, and the heights of the first magnetically conductive structure 41 and the second magnetically conductive structure 51 are both higher than that of the second magnet group 2.

[0044] The first magnetically conductive structure 41 works in conjunction with the second magnetically conductive structure 51 to guide the horizontal magnetic field to the metal coil 331 on the movable frame 33. In this application, for ease of illustration, the entire structure of the galvanometer chip is not shown.

[0045] The housing structure includes a base 42, an outer shell 52, a base 53, a first cover plate 61, and a second cover plate 62. The base 42 is used to fix the galvanometer chip. The outer shell 52, the base 42, and the base 53 are all made of non-magnetic materials. The outer shell 52 fits into the second magnetic structure 51. The base 42 cooperates with the first magnetic structure 41 to support the galvanometer chip. The first cover plate 61 and the second cover plate 62 are disposed on the upper side of the magnet assembly.

[0046] The first magnetically conductive structure 41, in conjunction with the base 42, provides a certain support for the galvanometer chip and is at least 1 mm higher than the second magnet group 2. The galvanometer chip is fixed to the support structure by the anchoring structure 32. The second magnetically conductive structure 51 and the outer shell 52 are both located on the outside of the galvanometer chip, compressing the height of the entire scanning galvanometer along the coaxial direction of the two fast axis beams 341 to the limit. The first cover plate 61 and the second cover plate 62 are used to fix the electrical connection device in the overall structure and provide a certain protection.

[0047] The movable frame 33 is square, circular, elliptical, or polygonal in shape; the torsion beam 34 has a beam structure of at least one of straight beam, ring beam, and folded beam; and the mirror 31 is square, circular, elliptical, rectangular, or polygonal in shape.

[0048] In this application, the structures of the components shown in the accompanying drawings are merely illustrative examples and should not be construed as limiting the scope of protection of this application.

[0049] Second embodiment:

[0050] Based on the first embodiment, please refer to Figure 11 and Figure 12 Unlike the first embodiment, the first magnet group 1 located outside the metal coil 331 is composed of an upper magnet 11 and a lower magnet 12 with opposite magnetization. The lower surface of the upper magnet 11 has opposite magnetic poles to the upper surface of the lower magnet 12. The height of the movable frame 33 of the galvanometer is located between the gaps of the upper and lower magnets 12, which can provide a driving magnetic field on the non-compressed height side. The driving magnetic field on the side requiring compression is provided by the second magnet group 2 below the movable frame 33 in conjunction with the magnetic conductive component.

[0051] Third embodiment:

[0052] Based on the first embodiment, please refer to Figure 13 Unlike the first embodiment, the magnet assembly consists of a second magnet group 2, a first magnetic guiding structure 41, and a second magnetic guiding structure 51. The movable frame 33 is a one-dimensional galvanometer. Under the action of electromagnetic force, the galvanometer twists around the axis CC'. The second magnet group 2 is located below the movable frame 33 and parallel to the torsion axis CC'. The magnetic field is guided to the vicinity of the movable frame 33 through the first magnetic guiding structure 41 and the second magnetic guiding structure 51, and the effective magnetic field component in the horizontal direction is maximized to provide sufficient driving force for the frame torsion. Compared with the structure where the magnet is located on the outside, the overall volume is effectively reduced.

[0053] Please see Figure 14The single-axis scanning galvanometer includes a mirror 31, an anchoring structure 32, a movable frame 33, and a metal coil 331, a torsion beam 34, and a connecting beam 343 thereon. The movable frame 33 is connected to the anchoring structure 32 via the connecting beam 343, and the movable frame 33 is connected to the reflecting mirror 31 via the torsion beam 34. The torsion beam 34 can be a thin straight beam structure as shown in the figure, or it can be a ring beam, a folded beam, or other beam structures. The mirror 31 is formed by evaporating or sputtering a metal reflective layer on the surface of silicon material. Its shape can be a square structure as shown in the figure, or it can be a circular, elliptical, rectangular, polygonal, or other structures. The magnetic drive assembly generates a magnetic field perpendicular to the CC' direction on the frame, as shown in the figure. The metal coil 331, located in the driving magnetic field, generates a Lorentz force after being energized. Under the action of the Lorentz force, the movable frame 33 and the mirror 31 will rotate together around the CC' axis via the torsion axis, ultimately realizing the single-axis scanning of the mirror 31.

[0054] The torsion beam includes a connecting beam and a fast-axis beam. The connecting beam connects the movable frame and the anchoring structure, and the fast-axis beam connects the movable frame and the mirror.

[0055] This invention discloses a scanning galvanometer driving device with compressed overall height. A horizontally magnetized magnet is placed below the metal coil 331, and the magnetic field direction is guided to the desired spatial position by a magnetically conductive component made of a magnetically conductive material, providing a strong magnetic field strength over a large spatial range. Simultaneously, the magnetically conductive component supports the galvanometer chip and the packaging housing without occupying additional space. Therefore, this application provides a strong magnetic field strength over a large spatial range while compressing the overall height of the electromagnetic galvanometer to its limit, achieving the technical effect of reducing the overall size of the lidar device and helping to enhance the market competitiveness of lidar.

[0056] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A scanning galvanometer driving device with compressed overall height dimension, characterized in that, It includes a galvanometer chip and a magnetic drive assembly. The galvanometer chip is disposed between the magnetic drive assemblies and fixed on a support structure. The galvanometer chip includes a mirror, an anchoring structure, a torsion beam, and a movable frame with a metal coil. The magnetic drive assembly includes a magnet assembly and a magnetic guide assembly. At least one magnet assembly consists of two magnets that are horizontally magnetized, have parallel magnetic surfaces, and have opposite magnetic poles. The magnet assembly is located below the galvanometer chip and works with the magnetic guide assembly to guide the driving magnetic field to the metal coil above. The magnet assembly includes two first magnetic conductive structures and two second magnetic conductive structures. The first magnetic conductive structures are located on the right side of the first magnet and the left side of the second magnet, respectively. The second magnetic conductive structures are located on the left side of the first magnet and the right side of the second magnet, respectively. The first magnetic conductive structures are also used to support and fix the galvanometer chip, and the second magnetic conductive structures are also used as the housing shell. The torsion beam includes a pair of fast-axis beams and a pair of slow-axis beams. The magnet assembly includes a first magnet group and a second magnet group. The first magnet group is located on both sides of the fast-axis drive side of the movable frame to provide a first driving magnetic field to drive the mirror to rotate about the coaxial line of the two fast-axis beams. The second magnet group is located below the slow-axis drive side of the movable frame and, in conjunction with the magnetic guiding structure, provides a second driving magnetic field to drive the movable frame and the mirror to rotate about the coaxial line of the two slow-axis beams. The magnetic conductive assembly includes a first magnetic conductive structure and a second magnetic conductive structure. The first magnetic conductive structure is disposed on the inner side below the metal coil, and the height of the second magnetic conductive structure is higher than that of the metal coil. The first magnetic conductive structure and the second magnetic conductive structure are mounted on both sides of the magnet of the second magnet group, and the height of the first magnetic conductive structure and the second magnetic conductive structure is higher than that of the second magnet group. The scanning galvanometer device with compressed overall height also includes a housing structure, which includes a base, an outer shell, a base, a first cover plate, and a second cover plate. The base cooperates with the first magnetically conductive structure to fix and support the galvanometer chip. The outer shell, the base, and the base are all made of non-magnetically conductive materials. The outer shell fits into the second magnetically conductive structure. The first cover plate and the second cover plate are disposed on the upper side of the magnet assembly. The first magnet group consists of two rectangular magnets that are magnetized horizontally, have parallel magnetic surfaces, and have opposite magnetic poles, or two sets of upper and lower magnet groups that are magnetized vertically, have opposite magnetic poles, and are located on the upper and lower sides of the galvanometer chip, respectively, to provide a driving magnetic field on the non-compressed height side of the scanning galvanometer driving device that compresses the overall height dimension. The galvanometer chip includes only a pair of torsion beams, and the magnet assembly includes only a pair of magnet groups and a magnetic guiding structure. The magnet group is located below the driving edge of the movable frame of the galvanometer chip and consists of a pair of horizontally magnetized first and second magnets, driving the galvanometer chip to rotate around the axis of the torsion beams. The movable frame is square, circular, elliptical, or polygonal in shape; the torsion beam has at least one of straight beam, ring beam, and folded beam structure; and the mirror is square, circular, elliptical, rectangular, or polygonal in shape.

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