Contact type large aperture large angle resonant scanning mirror

Abstract

The application discloses a contact type large-aperture large-angle resonant scanning mirror, which comprises a support, a mirror assembly, two groups of voice coil actuating assemblies, a laser emission module assembly, a light splitting assembly, a position measurement probe assembly and a control assembly.

Description

Technical Field

[0001] This invention relates to the field of precision optical and mechanical design technology, specifically to a contact-type large-aperture, large-angle resonant scanning mirror. Background Technology

[0002] Resonant scanning mirrors perform simple harmonic motion at a relatively fixed resonant frequency, resulting in higher scanning speeds compared to galvanometer-type scanning mirrors. Currently, MEMS resonant mirrors are all non-contact types. Contact-type mirrors have more complex structures and require more sophisticated control software. Non-contact mirrors have poor driving capability and limited load capacity, thus only able to drive small mirrors and small angles. MEMS mirrors use silicon wafer etching, resulting in poor surface shape. Furthermore, the mirror relies on an integral torsion beam formed by etching, which has poor mechanical strength and is prone to breakage under impact, making it unsuitable for high-impact applications such as military and aerospace. According to radar equations, the radar range is related to the scanning mirror aperture. Summary of the Invention

[0003] This invention provides a contact-type large-aperture, large-angle resonant scanning mirror to solve the problems of small aperture and poor impact resistance of existing MEMS scanning mirrors.

[0004] A contact-type large-aperture, large-angle resonant scanning mirror includes: a support frame, which is a rectangular parallelepiped structure with a hollow interior; a mirror assembly, fixedly mounted on one side wall of the support frame; two sets of voice coil actuation assemblies, fixedly mounted on opposite sides of the support frame adjacent to the mirror assembly; each set of voice coil actuation assemblies is connected to the mirror assembly via an elastic mechanism, and the vibration generated by the voice coil actuation assembly can be transmitted to the mirror assembly through the corresponding elastic mechanism, causing the mirror assembly to rotate due to oscillation; a laser emission module assembly, fixedly mounted on the top of the support frame; a beam splitter assembly, fixedly mounted inside the support frame and located below the laser emission module assembly; and a position measurement detector assembly, fixedly mounted... The laser emission module assembly is installed inside the bracket and is fixedly connected to the beam splitter assembly and the bracket, respectively. The laser emitted by the laser emission module assembly passes through the beam splitter assembly and the reflector assembly in sequence and is projected onto the center point of the position measurement detector assembly to form a laser spot. The laser spot is offset from the center point of the position measurement detector assembly as the reflector assembly swings. The control assembly is fixedly installed on one side wall of the bracket and is arranged opposite to the reflector assembly. The control assembly is connected to the voice coil actuation assembly and the position measurement detector assembly through circuits. The control assembly controls the vibration of the voice coil actuation assembly and simultaneously collects the position of the laser spot on the position measurement detector assembly to obtain the rotation angle of the reflector assembly.

[0005] Preferably, the reflector assembly includes: a reflector mounting bracket, fixedly mounted on a support; a reflector holder, connected to the reflector mounting bracket via a torsion beam; a main reflector, fixedly mounted on the reflector holder, with its mirror surface facing outwards from the support; and a miniature reflector, fixedly mounted at the center of the back of the main reflector, with its mirror surface facing inwards from the support.

[0006] Preferably, there are two reflector mounting brackets, which are fixedly installed at the top and bottom of the bracket respectively; the upper and lower ends of the reflector support are respectively connected to the corresponding reflector mounting brackets through torsion beams; wherein each reflector mounting bracket is connected to the corresponding torsion beam through fasteners.

[0007] Preferably, the main reflector is fixed to the reflector holder with adhesive; the miniature reflector is fixed to the center of the back of the main reflector with adhesive.

[0008] Preferably, each voice coil actuation assembly includes a coil, a magnet, a diaphragm, an actuator bracket, and a back cover; the voice coil actuation assembly is assembled in sequence according to the back cover, actuator bracket, magnet, coil, and diaphragm, and is mounted on the bracket via the actuator bracket.

[0009] Preferably, the elastic mechanism is a spring, with one end connected to the diaphragm of the voice coil actuation assembly and the other end connected to the reflector support, transmitting the vibration of the voice coil actuation assembly to the main reflector of the reflector assembly.

[0010] Preferably, the laser emitting module assembly includes a laser diode and a laser diode mounting bracket; the laser diode mounting bracket is fixedly installed on the top of the bracket, the laser diode is fixedly installed on the laser diode mounting bracket, and the emitting end of the laser diode faces the beam splitter assembly.

[0011] Preferably, the beam splitting assembly consists of a beam splitting lens and a lens holder, and is located at the center of the holder; the lens holder is fixedly connected to the position measurement detector assembly, and the beam splitting lens is fixedly mounted on the lens holder.

[0012] Preferably, the position measurement detector assembly includes: a position detector and a position detector mounting bracket; the position detector mounting bracket is fixedly connected to a lens bracket and a bracket respectively, and the position detector is fixedly mounted on the position detector mounting bracket.

[0013] Preferably, the control component is electrically connected to the coils of the position detector and each voice coil actuation component, respectively, and collects the specific position information of the laser spot formed on the position detector, and drives the voice coil actuation component to vibrate.

[0014] The technical solution provided by this invention may include the following beneficial effects:

[0015] 1. The resonant scanning mirror of the present invention is designed with a contact transmission mechanism, which has high transmission efficiency and is driven by a dual voice coil actuator. Compared with MEMS scanning mirrors, it has a strong load capacity and can drive large-diameter glass reflectors at large angles, which can effectively improve the working distance of devices such as lidar.

[0016] 2. This invention can drive glass lenses with a diameter of 25mm or more, and the angle can reach over 60°. The large diameter and large angle are due to the use of a direct contact transmission method.

[0017] 3. The resonant scanning mirror of the present invention uses a spring as a transmission mechanism. Since the spring itself has good impact resistance, compared with the traditional silicon wafer-based MEMS scanning mirror, it effectively improves the mechanical resistance of the scanning mirror and can meet the requirements of aerospace, military and other harsh working conditions.

[0018] 4. The resonant scanning mirror of the present invention is a highly integrated opto-mechatronics system. All functional components such as control, actuation, and measurement are integrated inside the scanning mirror. During operation, no other instruments or equipment are required except for providing the necessary electrical signals. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is an external schematic diagram of the resonant scanning mirror of the present invention.

[0021] Figure 2 This is a cross-sectional schematic diagram of the resonant scanning mirror of the invention.

[0022] Figure 3 This is a schematic diagram showing the connection relationship of the reflector assembly of the invention.

[0023] Figure 4 This is a schematic diagram of the composition of the voice coil actuation assembly of the invention.

[0024] Figure 5 This is a schematic diagram of the internal optical path of the resonant scanning mirror of the invention.

[0025] Figure 6 This is a schematic diagram illustrating the angle measurement principle of the invention. Detailed Implementation

[0026] Embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be more thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0027] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms “a,” “the,” and “the” used in this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0028] like Figure 1 and Figure 2 As shown, the present invention provides a contact-type large-aperture, large-angle resonant scanning mirror. It includes a reflector assembly 1, an elastic mechanism 2, two sets of voice coil actuation assemblies 3, a position measurement detector assembly 4, a laser emission module assembly 5, a beam splitting assembly 6, a control assembly 7, and a support 8.

[0029] The support 8 is a cuboid structure with a hollow interior. The elastic mechanism 2, the position measurement detector assembly 4, and the beam splitter assembly 6 are located inside the support 8. The reflector assembly 1 and the control assembly 7 are arranged opposite each other on the two side walls of the support 8. The two sets of voice coil actuation assemblies 3 are arranged opposite each other on the other two side walls of the support 8. The laser emission module assembly 5 is located on the top of the support 8, and the laser emitted by it passes through the beam splitter assembly 6 and the reflector assembly 1 in sequence before entering the position measurement detector assembly 4. When the resonant scanning mirror is in operation, all functional components such as the control assembly 7, the two sets of voice coil actuation assemblies 3, and the position measurement detector assembly 4 are integrated inside the scanning mirror. During operation, in addition to providing the necessary electrical signals, no other instruments or equipment are required, thus realizing a highly integrated opto-mechatronic system.

[0030] Furthermore, such as Figure 3As shown, two elastic mechanisms 2 are provided; the reflector assembly 1 is fixedly installed on one side wall of the bracket 8; two sets of voice coil actuation assemblies 3 are respectively fixedly installed on the two side walls adjacent to the side wall of the bracket 8 where the reflector assembly 1 is located, and are arranged opposite to each other. Each voice coil actuation assembly 3 is connected to the reflector assembly 1 through a corresponding elastic mechanism 2, that is, each voice coil actuation assembly 3 is connected to one end of the corresponding elastic mechanism 2, and the other end of each elastic mechanism 2 is connected to the reflector assembly 1. Therefore, the micro-vibration generated by the voice coil actuation assembly 3 can be transmitted to the reflector assembly 1 through the corresponding elastic mechanism 2, thereby adjusting the scanning angle range by controlling the vibration amplitude of the voice coil actuation assembly 3. The resonant scanning mirror adopts a contact transmission mechanism with high transmission efficiency, is driven by dual voice coil actuators, has strong load capacity, and can drive large-diameter glass reflectors at large angles, which can effectively improve the working distance of equipment such as lidar.

[0031] like Figure 3 and Figure 5 As shown, the reflector assembly 1 includes a main reflector 9, a reflector support 10, a miniature reflector 11, a torsion beam 12, and a reflector mounting bracket 13; wherein, the reflector mounting bracket 13 is fixedly mounted on the bracket 8, and the reflector mounting bracket 13 and the reflector support 10 are connected through the torsion beam 12; the main reflector 9 is fixed on the reflector support 10, and its mirror surface is arranged facing the outside of the bracket 8; the miniature reflector 11 is fixed to the back of the main reflector 9, that is, its mirror surface is arranged facing the inside of the bracket 8.

[0032] Preferably, two reflector mounting brackets 13 are provided, respectively fixedly installed at the top and bottom of the bracket 8; the upper and lower ends of the reflector support 10 are respectively connected to the corresponding reflector mounting brackets 13 via torsion beams 12. Each reflector mounting bracket 13 is connected to the corresponding torsion beam 12 by a fastening screw. The tension of the torsion beam 12 is adjusted by tightening the fastening screw, thereby ensuring that both the upper and lower ends of the installed reflector support 10 are tightened, thus achieving a fixed installation of the reflector support 10; the miniature reflector 11 is fixed at the center of the back of the main reflector 9 to improve the accuracy of the measurement data.

[0033] In a preferred embodiment, the main reflector 9 is fixed to the reflector holder 10 with adhesive; the miniature reflector 11 is fixed to the back of the main reflector 9 with adhesive, thereby increasing the firmness and ensuring the stability of the reflector in the device.

[0034] like Figure 4As shown, each voice coil actuation assembly 3 includes a coil 14, a magnet 15, a diaphragm 16, an actuator bracket 17, and a rear cover 18. These components are sequentially connected and assembled in the order of rear cover 18, actuator bracket 17, magnet 15, coil 14, and diaphragm 16, and are mounted on the bracket 8 via the actuator bracket 17. The diaphragm 16 of the voice coil actuation assembly 3 faces outwards from the bracket 8, while the rear cover 18 faces inwards from the bracket 8. Further, as... Figure 3 As shown, the elastic mechanism 2 adopts a spring-type transmission mechanism, with one end fixed to the diaphragm 16 of the voice coil actuation assembly 3 and the other end fixed to the back of the reflector support 10, thereby connecting the reflector assembly 1 and the voice coil actuation assembly 3, and transmitting the vibration of the voice coil actuation assembly 3 to the main reflector 9 of the reflector assembly 1. This embodiment uses a spring as the transmission mechanism. Because the spring itself has good impact resistance, it effectively improves the mechanical properties of the scanning mirror, meeting the requirements of aerospace, military, and other harsh working conditions.

[0035] The laser emitting module assembly 5 is fixedly connected to the bracket 8 and is located on the top of the bracket 8; the position measurement detector assembly 4 is fixedly connected to the beam splitter assembly 6, and the beam splitter assembly 6 is located directly below the laser emitting module assembly 5; the control assembly 7 is fixedly mounted on one side wall of the bracket 8 and is positioned opposite to the reflector assembly 1. The fixed connection between these components and the bracket 8 makes the entire device more stable and ensures the stability of its operation.

[0036] like Figure 5 As shown, the laser emitting module assembly 5 includes a laser diode 19 and a laser diode mounting bracket 20. The laser diode mounting bracket 20 is fixedly mounted on the top of the bracket 8, and the laser diode 19 is fixedly mounted on the laser diode mounting bracket 20, with the emitting end of the laser diode 19 facing the beam splitter assembly 6.

[0037] like Figure 5 As shown, the beam splitting assembly 6 consists of a beam splitter 21 and a lens holder 22, and is located at the center of the support 8. The lens holder 22 is fixedly connected to the position measurement detector assembly 4, and the beam splitter 21 is fixedly mounted on the lens holder 22 and tilted at a certain angle to receive the laser emitted by the laser diode 19 and split the laser into reflected light and transmitted light.

[0038] Preferably, the beam splitter 21 is tilted at a 45° angle to the vertical direction to split the laser emitted by the laser diode 19 into reflected light and transmitted light. Further, a dielectric film is deposited on the surface of the beam splitter 21. This film can split the laser emitted by the laser diode 19 incident at 45° into 50% reflected light and 50% transmitted light. This 50% splitting ratio minimizes overall laser loss and achieves better beam splitting effect. The reflected light, after being reflected again by the miniature reflector 11 in the reflector assembly 1, is transmitted through the beam splitter 21 and then incident on the center point of the position detector 23 in the position measurement detector assembly 4 to form a laser spot.

[0039] like Figure 5 As shown, the position measurement detector assembly 4 includes a position detector 23 and a position detector mounting bracket 24. The position detector mounting bracket 24 is fixedly connected to the lens bracket 22 and the bracket 8, and the position detector 23 is fixedly mounted on the position detector mounting bracket 24.

[0040] Preferably, the laser wavelength emitted by the laser diode 19 is adapted to the position detector 23 to ensure measurement accuracy.

[0041] The control component 7 is electrically connected to the position detector 23 and the coil 14 of each voice coil actuation component 3, respectively. It collects the specific position of the laser spot formed on the position detector 23 and drives the control voice coil actuation component 3.

[0042] Specifically, control component 7 supplies power to voice coil actuator 3. When current flows through coil 14, a magnetic field is formed around coil 14. The magnetic field formed by coil 14 interacts with the magnetic field between magnet 15. Coil 14 is energized and subjected to force in the magnetic field, causing it to move. When the current flowing through coil 14 is alternating current, the direction of the force on coil 14 also periodically reverses with the direction of the current. As a result, coil 14 drives diaphragm 16 to vibrate at the same frequency as the alternating current in coil 14. Diaphragm 16 drives the entire voice coil actuator 3 to vibrate at the same frequency. Furthermore, the two voice coil actuators 3 drive the main reflector 9 to swing back and forth through elastic mechanism 2. During the swinging process, the main reflector 9 will rotate by an angle θ.

[0043] Meanwhile, the laser emitted by the laser diode 19 of the laser emission module assembly 5 forms a laser spot on the position detector 23 after multiple reflections and transmissions through the beam splitter 21 and the micro reflector 11. However, because the main reflector 9 will rotate due to vibration and oscillation during this process, the micro reflector 11 located on its back is also driven to oscillate, resulting in the laser spot projected onto the position detector 23 being offset from the center point of the position detector 23 by a certain distance.

[0044] Furthermore, since the overall resonant frequency of the scanning mirror is an inherent property, obtained through measurement during debugging, and the inherent frequency varies between different scanning mirrors, it is related to the size of the mirror, the parameters of the transmission mechanism, and so on. Therefore, when the vibration frequency of the voice coil actuation component 3 is close to the resonant frequency, the swing amplitude of the main reflector 9 increases significantly, the scanning accuracy of the scanning mirror is greater, and thus large-angle scanning is achieved. When the vibration frequency of the voice coil actuation component 3 matches the overall resonant frequency of the scanning mirror, optimal simple harmonic vibration occurs.

[0045] The principle for measuring the rotation angle of the primary reflector 9 is as follows: Figure 6 As shown, the relationship between the angle and position detector outputs is obtained through measurement calibration and fitting, and the formula is as follows:

[0046]

[0047] θ is the rotation angle of the main reflector, m is the distance from the laser spot to the center of the position detector, and l is the horizontal distance from the center of the main reflector to the center of the position detector.

[0048] The following are specific embodiments of the present invention:

[0049] like Figure 5 , Figure 6 As shown, the laser diode 19 of the laser emitting module assembly 5 emits laser light ① towards the beam splitter assembly 6. After passing through the beam splitter lens 21 of the beam splitter assembly 6, the laser light is reflected ②. The reflected light ② is reflected again by the miniature reflector 11 in the reflector assembly 1 to form reflected light ③. The reflected light ③ generates transmitted light ④ at the beam splitter lens 21. The transmitted light ④ is incident on the position detector 23 in the position measurement detector assembly 4 to form a laser spot. During the measurement process, the vibration amplitude of the voice coil actuation assembly 3 is controlled by the control assembly 7 to adjust the scanning angle range. At the same time, the rotation angle of the main reflector 9 can be obtained by acquiring the position of the laser spot on the position detector 23.

[0050] Specifically, since the control component 7 controls the voice coil actuator 3 to vibrate, the main reflector 9 in the reflector assembly 1 will rotate. At this time, the micro reflector 11 will also rotate. The laser spot will move relative to its center position on the position detector 23. The rotation angle of the main reflector 9 corresponds one-to-one with the position of the laser spot on the position detector 23. The position detector 23 will output a signal related to the position of the laser spot (i.e., the data m and l mentioned above). The rotation angle of the main reflector 9 can be obtained by processing these two sets of data according to the above formula.

[0051] The above description is merely an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and scope of the present invention are included within the scope of protection of the present invention.

Claims

1. A contact-type large-aperture, large-angle resonant scanning mirror, characterized in that, include: The support (8) is a cuboid structure with a hollow interior; The reflector assembly (1) is fixedly installed on one side wall of the bracket (8); Two sets of voice coil actuation components (3) are fixedly installed on the side walls of the bracket (8) adjacent to the reflector assembly (1); and each set of voice coil actuation components (3) is connected to the reflector assembly (1) through an elastic mechanism (2). The vibration generated by the voice coil actuation component (3) can be transmitted to the reflector assembly (1) through the corresponding elastic mechanism (2) so that the reflector assembly (1) can rotate due to the swing. The laser emission module assembly (5) is fixedly installed on the top of the bracket (8); The beam splitting component (6) is fixedly installed inside the bracket (8) and located below the laser emitting module component (5); The position measurement detector assembly (4) is fixedly installed inside the bracket (8) and is fixedly connected to the beam splitter assembly (6) and the bracket (8) respectively; the laser emitted by the laser emission module assembly (5) passes through the beam splitter assembly (6) and the reflector assembly (1) in sequence and is projected onto the center point of the position measurement detector assembly (4) to form a laser spot, and the laser spot is offset from the center point of the position measurement detector assembly (4) as the reflector assembly (1) swings; The control component (7) is fixedly installed on one side wall of the bracket (8) and is positioned opposite to the reflector assembly (1). The control component (7) is connected to the voice coil actuation assembly (3) and the position measurement detector assembly (4) via circuits. The control component (7) controls the vibration of the voice coil actuation assembly (3) and simultaneously collects the position of the laser spot on the position measurement detector assembly (4) to obtain the rotation angle of the reflector assembly (1).

2. The contact-type large-aperture, large-angle resonant scanning mirror as described in claim 1, characterized in that, The mirror assembly (1) includes: The reflector mounting bracket (13) is fixedly installed on the bracket (8); The reflector support (10) is connected to the reflector fixing bracket (13) via a torsion beam (12); The main reflector (9) is fixedly mounted on the reflector holder (10), and its mirror surface is positioned facing the outside of the bracket (8); A miniature reflector (11) is fixedly installed at the center of the back of the main reflector (9), with its mirror surface facing the inside of the bracket (8).

3. The contact-type large-aperture, large-angle resonant scanning mirror as described in claim 2, characterized in that, Two reflector fixing brackets (13) are provided, which are fixedly installed on the top and bottom of the bracket (8) respectively; the upper and lower ends of the reflector support (10) are connected to the corresponding reflector fixing brackets (13) through torsion beams (12); Each of the aforementioned mirror mounting brackets (13) is connected to the corresponding torsion beam (12) by fasteners.

4. A contact-type large-aperture, large-angle resonant scanning mirror as described in claim 3, characterized in that, The main reflector (9) is fixed to the reflector holder (10) with adhesive; the miniature reflector (11) is fixed to the center of the back of the main reflector (9) with adhesive.

5. A contact-type large-aperture, large-angle resonant scanning mirror as described in claim 3, characterized in that, Each of the voice coil actuators (3) includes a coil (14), a magnet (15), a diaphragm (16), an actuator bracket (17), and a back cover (18); The voice coil actuator assembly (3) is connected and assembled in sequence according to the back cover (18), actuator bracket (17), magnet (15), coil (14), and diaphragm (16), and is mounted on the bracket (8) through the actuator bracket (17).

6. A contact-type large-aperture, large-angle resonant scanning mirror as described in claim 5, characterized in that, The elastic mechanism (2) uses a spring, with one end connected to the diaphragm (16) of the voice coil actuation assembly (3) and the other end connected to the reflector support (10), to transmit the vibration of the voice coil actuation assembly (3) to the main reflector (9) of the reflector assembly (1).

7. A contact-type large-aperture, large-angle resonant scanning mirror as described in claim 1, characterized in that, The laser emitting module assembly (5) includes a laser diode (19) and a laser diode mounting bracket (20); The laser diode mounting bracket (20) is fixedly installed on the top of the bracket (8), and the laser diode (19) is fixedly installed on the laser diode mounting bracket (20), with the emitting end of the laser diode (19) facing the beam splitter (6).

8. A contact-type large-aperture, large-angle resonant scanning mirror as described in claim 7, characterized in that, The beam splitting assembly (6) consists of a beam splitting lens (21) and a lens holder (22), and is located at the center of the holder (8); The lens holder (22) is fixedly connected to the position measurement detector assembly (4), and the beam splitter (21) is fixedly mounted on the lens holder (22).

9. A contact-type large-aperture, large-angle resonant scanning mirror as described in claim 8, characterized in that, The position measurement detector assembly (4) includes: a position detector (23) and a position detector mounting bracket (24); The position detector fixing bracket (24) is fixedly connected to the lens bracket (22) and the bracket (8) respectively, and the position detector (23) is fixedly installed on the position detector fixing bracket (24).

10. A contact-type large-aperture, large-angle resonant scanning mirror as described in claim 9, characterized in that, The control component (7) is electrically connected to the position detector (23) and the coil (14) of each voice coil actuation component (3), respectively. It collects the specific position information of the laser spot formed on the position detector (23) and drives the voice coil actuation component (3) to vibrate.

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