Moving magnet electromagnetic drive dual-axis optical scanning mirror, array and applications thereof

Abstract

The application provides a moving-magnet electromagnetic driving double-shaft optical scanning mirror, array and application thereof. The optical scanning mirror comprises an optical mirror, a permanent magnet, a double-shaft torsion mechanism and a driving electromagnet. The optical mirror is connected with one end of the permanent magnet, the middle of the permanent magnet is connected with the double-shaft torsion mechanism, the driving magnetic field generated by the driving electromagnet intersects with the magnetic moment of the permanent magnet, the permanent magnet is subjected to the electromagnetic torque and is subjected to the torsion movement, the optical mirror is located above the double-shaft torsion mechanism, the planes where the optical mirror and the double-shaft torsion mechanism are located are parallel to each other, and the vertical distance between the optical mirror and the double-shaft torsion mechanism satisfies the space requirement when the optical mirror rotates within the maximum scanning angle, the driving electromagnet comprises three or more than three air gap magnetic poles, the air gap magnetic poles are symmetrically distributed, the middle of the air gap magnetic poles constitutes an electromagnet air gap, the permanent magnet is located in the middle of the electromagnet air gap, and the size of the electromagnet air gap satisfies the space requirement when the permanent magnet rotates within the maximum scanning angle. The application can realize large mirror size and large angle scanning.

Description

Technical Field

[0001] This invention relates to the field of optical scanning mirror technology, and in particular to a moving-magnetic-driven dual-axis optical scanning mirror, array, and their applications. Background Technology

[0002] With the success and increasingly widespread application of laser technology in fields such as lidar, laser communication, laser processing, laser imaging, and laser 3D printing, there is a huge demand for related laser optical components. In particular, optical scanning mirrors are an indispensable core component in laser applications. Laser scanning using optical scanning mirrors can achieve laser drawing and generation of specific patterns, laser pointing, and laser tracking. Therefore, optical scanning mirrors have broad application prospects and huge market demand.

[0003] Optical scanning mirrors achieve beam scanning by using a motor to drive the optical mirror to twist or rotate. Currently, optical scanning is divided into four types: galvanometer scanning, rotating mirror scanning, optical wedge scanning, and fast-reflecting mirror, each with the following characteristics:

[0004] 1) Galvanometer Scanning: This method uses a torsion motor to drive an optical mirror. The basic principle is that the driving current of the coil generates electromagnetic torque in a bias magnetic field, which balances the torque generated by the mechanical springs of the rotor, proportional to the torsion angle. This torsion motor is a reciprocating angular deflector, with the deflection angle proportional to the driving current, similar to the working principle of a magnetoelectric galvanometer. Therefore, the galvanometer is also called a galvanometric scanner. Galvanometers can only perform single-axis scanning. Due to the large mass and rotational inertia of the rotor and mirror, the scanning frequency can only reach several hundred Hz. Furthermore, the optical duty cycle of the galvanometer is small, and the consistency is poor, making arraying difficult.

[0005] 2) Rotating mirror scanning: A high-speed motor drives a multi-faceted mirror to rotate continuously in one direction, achieving unidirectional beam scanning without retrace. The scanning angular velocity is usually fixed. The high-speed rotation of the multi-faceted mirror in rotating mirror scanning generates enormous centrifugal force, limiting the scanning speed to several hundred revolutions per second. Similarly, rotating mirrors also suffer from drawbacks such as single-axis scanning, low optical duty cycle, and poor consistency, making arraying difficult.

[0006] 3) Optical wedge scanning: Two optical wedges connected in series are driven by two motors to achieve transmissive two-dimensional scanning of the laser beam. However, its scanning pattern is special and different from the usual grating scanning. It also has shortcomings such as low optical duty cycle and poor consistency, making it difficult to achieve arraying.

[0007] 4) Fast-reflecting mirror: Three (or four) piezoelectric actuators or voice coil motor actuators drive a dual-axis flexible mechanism, on which optical mirrors are mounted to achieve dual-axis scanning of the laser beam. Fast-reflecting mirrors have a very small scanning angle and exhibit significant hysteresis, requiring closed-loop feedback to achieve linear drive.

[0008] The traditional optical scanning mirrors described above are sophisticated and complex scanning mechanisms. They are large in size, heavy in weight, have low optical duty cycle, are inflexible in beam scanning, are expensive, and are complex to control, and can only be used in specific application scenarios.

[0009] With the maturity of MEMS technology and its integration with optical technology, optical MEMS technology has been developed. MEMS scanning mirrors are a successful device in optical MEMS technology. They have many advantages such as fast scanning speed, multi-axis scanning, small size, mass production, low cost, and good consistency. They have become the mainstream technology for low laser power and small-size mirror laser scanning and have broad market prospects in lidar, laser communication and other fields.

[0010] From the perspective of scanning methods, MEMS scanning mirrors can be divided into resonant MEMS scanning mirrors and quasi-static MEMS scanning mirrors, or a combination of both. Resonant scanning can achieve a large scanning angle by utilizing the mechanical resonance effect, but it cannot achieve vector scanning of arbitrary areas, and it is sensitive to ambient temperature, with unstable scanning gratings. Quasi-static scanning mirrors can achieve vector scanning of arbitrary areas, but the scanning angle is small, typically only reaching a few degrees.

[0011] From the perspective of MEMS driving methods, MEMS scanning mirrors mainly include four types: electrostatic driving, electromagnetic driving, piezoelectric driving, and electrothermal driving. Among them, electrostatic driving is the most mature and widely used driving method. Electrostatic driving has a relatively low force density, and both the driving force and torque are small. Therefore, the mirror size of electrostatic scanning mirrors is usually between 10 micrometers and 3000 micrometers, and its scanning angle range is also small. Moreover, the mirror size and scanning angle range are mutually constrained. In contrast, electromagnetic driving has a higher force density, which can achieve a larger driving force and torque. Therefore, the mirror size of electromagnetic scanning mirrors can reach 5000 micrometers, and its scanning angle range can reach 30° (H, resonant scanning mode) × 20° (V, quasi-static scanning mode). Similarly, its mirror size and scanning angle range are mutually constrained. Currently, electromagnetic driving usually involves fabricating MEMS coils on the moving frame of the micromirror, i.e., using moving coil electromagnetic actuators. The number of coil turns is very limited, generally only 20-30 turns, and the bias magnetic field air gap is large. Therefore, its driving power consumption is relatively high and its driving efficiency is not high. Moving coil electromagnetic actuators, with only one set of coils and a single deflection magnetic field, find it difficult to achieve dual-axis scanning, and can only achieve resonant scanning on one axis and quasi-static scanning on the other. Another type of electromagnetic scanning mirror uses the principle of attraction and repulsion between magnetic poles, requiring a large air gap between the magnetic poles. This causes the driving to exhibit significant nonlinearity or even magnetic attraction after the mirror scanning exceeds a certain angle, and the driving efficiency is low.

[0012] MEMS scanning mirrors typically have small mirror sizes, currently only a few millimeters in diameter. Furthermore, the size of the scanning mirror and the scanning angle range are mutually restrictive, making it difficult to simultaneously achieve large mirror sizes and large scanning angles. Additionally, existing MEMS scanning mirror technologies only have an optical duty cycle of 10-20%, hindering high duty cycle array applications. Solving these current technical challenges and developing MEMS scanning mirrors with large mirror sizes, large scanning angles, and high duty cycles is key to expanding the application market for MEMS scanning mirrors. Summary of the Invention

[0013] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a moving magnet electromagnetic drive dual-axis optical scanning mirror, array and its application, to solve the problems of traditional optical scanning mirrors being large in size, heavy in weight, low optical duty cycle, inflexible beam scanning, high cost, complex control, and only applicable to specific application scenarios, and existing MEMS scanning mirrors being difficult to achieve high duty cycle array applications.

[0014] To achieve the above and other related objectives, this invention provides a moving-magnet type electromagnetically driven dual-axis optical scanning mirror, comprising an optical mirror, a permanent magnet, a dual-axis torsion mechanism, and a driving electromagnet. The optical mirror is connected to the permanent magnet, and the permanent magnet is connected to the dual-axis torsion mechanism in the middle. The driving magnetic field generated by the driving electromagnet intersects with the magnetic moment of the permanent magnet, causing the permanent magnet to undergo torsional motion under the action of electromagnetic torque. The optical mirror is located above the dual-axis torsion mechanism, and the planes on which they are located are parallel to each other. The vertical distance between them satisfies the spatial requirements for the optical mirror to rotate within the maximum scanning angle, thereby forming a concealed driving structure. The driving electromagnet includes three or more air-gap magnetic poles, which are symmetrically distributed. The air gap between the air gap magnetic poles forms an electromagnet air gap, and the permanent magnet is located in the middle of the electromagnet air gap. The size of the electromagnet air gap satisfies the spatial requirements for the permanent magnet to rotate within the maximum scanning angle.

[0015] The present invention also provides a moving-magnetic electromagnetic drive dual-axis optical scanning mirror array, which includes a plurality of moving-magnetic electromagnetic drive dual-axis optical scanning mirrors as described in any of the foregoing embodiments, and the plurality of moving-magnetic electromagnetic drive dual-axis optical scanning mirrors are arranged in an array in the same plane.

[0016] The present invention also provides an application of the moving magnet electromagnetic drive dual-axis optical scanning mirror or array as described in any of the above embodiments, wherein the moving magnet electromagnetic drive dual-axis optical scanning mirror or array is applied to any one of laser phased array, laser communication, lidar, and laser weapon.

[0017] As described above, the moving-magnetic-driven dual-axis optical scanning mirror, array, and their applications of the present invention have the following beneficial effects: The moving-magnetic-driven dual-axis optical scanning mirror and array proposed in this invention adopt the torque output type moving-magnetic-driven electromagnetic principle. Through a hidden mirror-dual-axis torsion mechanism-electromagnet three-layer structure design, it ensures that the center of mass of the permanent magnet coincides with the rotation center of the electromagnetic actuator, and provides sufficient motion space for large-angle scanning of the mirror, thereby realizing a pure torque drive that is theoretically free of net force. Therefore, compared with the prior art, the present invention has the following beneficial effects:

[0018] 1) Achieve large mirror size to improve the energy and signal-to-noise ratio of optical signals received by lidar and laser communication systems;

[0019] 2) Dual-axis independent scanning greatly simplifies the scanning control algorithm;

[0020] 3) Wide-angle scanning can meet the technical requirements of wide field of view and wide-range scanning for lidar and laser communication;

[0021] 4) Dual-axis scanning can simultaneously achieve quasi-static scanning, enabling vector scanning of any region, thus improving the flexibility and effectiveness of scanning;

[0022] 5) The high duty cycle hidden drive structure can not only reduce the horizontal size of the optical scanning mirror unit, but also form a high duty cycle scanning mirror array.

[0023] 6) The linear drive curve of electromagnetic drive greatly simplifies the drive control algorithm of electromagnetic drive, providing a good technical foundation for high-precision drive;

[0024] 7) High-efficiency electromagnetic torsion drive, low power consumption, less heat generation of the scanning mirror itself, and more stable operation of the scanning mirror, which is also of great significance for arrayed scanning mirrors and aerospace applications.

[0025] The above-mentioned beneficial effects are advantages that existing technologies cannot achieve. This invention, however, simultaneously possesses these technical advantages, overcoming the technical challenge of the mutual constraints between mirror size and scanning angle in existing optical scanning technologies. It solves the pain points of applying optical scanning mirrors to lidar, space laser communication, laser phased arrays, etc., and can fully meet application requirements. Attached Figure Description

[0026] Figure 1 The diagram shown is a schematic diagram of the assembly structure of the moving magnet electromagnetic drive biaxial optical scanning mirror provided in Embodiment 1 of the present invention.

[0027] Figure 2 Displayed as Figure 1 A schematic diagram of its decomposed structure.

[0028] Figure 3 Displayed as Figure 2 A top view of the universal joint structure.

[0029] Figure 4 Displayed as Figure 2 A schematic diagram of the packaging structure.

[0030] Figure 5 Displayed as Figure 2 A schematic diagram showing the connection between the driving electromagnet and the packaging structure.

[0031] Figure 6 Displayed as Figure 5 A schematic diagram of its decomposed structure.

[0032] Figure 7 The diagram shows the structure of the driving electromagnet of the moving-magnet electromagnetically driven biaxial optical scanning mirror provided by the present invention.

[0033] Figure 8 Displayed as Figure 7 A schematic diagram of its decomposed structure.

[0034] Figure 9 Displayed as Figure 8 A schematic diagram of the iron core structure.

[0035] Figure 10 The diagram shows the positional relationship of the air gap magnetic poles of the moving-magnetic-driven biaxial optical scanning mirror provided by the present invention.

[0036] Figure 11 The diagram shown is a schematic diagram of the driving electromagnet of the moving-magnet electromagnetically driven biaxial optical scanning mirror provided in Embodiment 2 of the present invention.

[0037] Figure 12 The diagram shown is a schematic diagram of the biaxial torsion mechanism of the moving magnet type electromagnetically driven biaxial optical scanning mirror provided in Embodiment 2 of the present invention.

[0038] Figure 13 and 14 The diagram shows structural schematics of the moving magnet electromagnetic drive biaxial optical scanning mirror array provided in Embodiment 3 of the present invention in different examples. Detailed Implementation

[0039] The following specific examples illustrate the embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. For ease of explanation, when detailing the embodiments of the present invention, the cross-sectional views showing the device structure are partially enlarged, not according to the general scale, and the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. Furthermore, in actual manufacturing, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0040] For ease of description, spatial relation terms such as “below,” “under,” “lower than,” “below,” “above,” and “upper” may be used herein to describe the relationship between one element or feature shown in the accompanying drawings and other elements or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the drawings for devices in use or operation. Furthermore, when a layer is referred to as being “between” two layers, it may be the only layer between the two layers, or there may be one or more layers in between.

[0041] In the context of this application, the structure described above the first feature may include embodiments in which the first and second features are formed in direct contact, or embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0042] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show components related to the present invention and are not drawn according to the actual number, shape, and size of the components in the actual implementation. In the actual implementation, the form, quantity, and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex. To keep the illustrations as concise as possible, not all structures are shown in the figures.

[0043] Please see Figures 1 to 14 .

[0044] like Figure 1-12 As shown, this invention provides a moving-magnet type electromagnetically driven dual-axis optical scanning mirror, including an optical mirror 1, a permanent magnet 2, a dual-axis torsion mechanism, and a driving electromagnet 5. The optical mirror 1 is connected to one end of the permanent magnet 2, and the permanent magnet 2 is connected to the dual-axis torsion mechanism in the middle. The driving magnetic field B generated by the driving electromagnet 5 intersects with the magnetic moment M of the permanent magnet 2, causing the permanent magnet 2 to undergo torsional motion under the action of an electromagnetic torque τ. These structures together constitute the moving-magnet type electromagnetically driven dual-axis optical scanning mirror. More specifically, the optical mirror 1 is located above the dual-axis torsion mechanism, and the two are located... The planes are parallel to each other, and the vertical distance between them meets the spatial requirements of the optical mirror 1 when it rotates within the maximum scanning angle, thus forming a hidden driving structure; the driving electromagnet 5 includes three or more air gap magnetic poles 511, which are symmetrically distributed, for example, in a centrally symmetrical distribution. The air gap magnetic poles 511 form an electromagnet air gap in the middle, and the permanent magnet 2 is located in the middle of the electromagnet air gap, usually at the exact center of the electromagnet air gap. The size of the electromagnet air gap meets the spatial requirements required for the permanent magnet to rotate within the maximum scanning angle.

[0045] The proposed invention uses a moving magnet electromagnetic drive dual-axis optical scanning mirror and its array. It adopts the torque output type moving magnet electromagnetic drive principle. Through the hidden mirror-dual-axis torsion mechanism-electromagnet three-layer structure design, it ensures that the center of mass of the permanent magnet coincides with the rotation center of the electromagnetic driver and provides sufficient motion space for large-angle scanning of the mirror. Thus, the electromagnetic drive structure can generate a pure torque drive that is theoretically free of net force. Therefore, compared with the prior art, the present invention has the following beneficial effects: 1) It achieves a large mirror size, improving the energy and signal-to-noise ratio of the received optical signals in lidar and laser communication systems; 2) Dual-axis independent scanning greatly simplifies the scanning control algorithm; 3) Large-angle scanning can meet the technical requirements of lidar and laser communication for large field of view and wide-range scanning; 4) Dual-axis can simultaneously achieve quasi-static scanning, enabling vector scanning of any region, improving the flexibility and effectiveness of scanning; 5) The high duty cycle hidden drive structure can not only reduce the horizontal size of the optical scanning mirror unit, but also form a high duty cycle scanning mirror array; 6) The linear drive curve of electromagnetic drive greatly simplifies the drive control algorithm of electromagnetic driver, providing a good technical foundation for high-precision drive; 7) The efficient electromagnetic torsional drive consumes low power, generates less heat in the scanning mirror itself, and makes the scanning mirror operation more stable, which is also of great significance for arrayed scanning mirrors and aerospace applications.

[0046] The optical mirror 1 includes, but is not limited to, a high-quality optical mirror made of single-crystal silicon and aluminum, the surface of which may be further coated with an optical reflective film, such as a gold layer, and the mirror shape includes, but is not limited to, one of the following: a circle, an ellipse, a square, a rectangle, and a regular hexagon with central symmetry.

[0047] In a further example, the back of the optical mirror 1 is designed with a hollow structure to further reduce its mass and provide scanning flexibility. The back of the optical mirror 1 is also provided with a support connection structure, which connects to one end of the permanent magnet 2. Preferably, the support connection structure of the optical mirror 1 is connected to the permanent magnet 2 using low-stress adhesive, which improves assembly flexibility and reduces damage to the optical mirror 1.

[0048] The optical mirror 1 has a mirror size of 2mm-50mm (the mirror size is the extended dimension of the mirror along the arrangement direction; for example, when the mirror is circular, this dimension refers to its diameter, and when the mirror is rectangular, this dimension refers to the side length of the rectangle) to ensure that high optical quality can be obtained while meeting the diffraction optical limit mirror quality requirements.

[0049] In one example, the optical angle scanning range of the moving magnet electromagnetic drive dual-axis optical scanning mirror is -60° to 60°, but it is not limited to this and can be further expanded as needed. The scanning method includes any one of quasi-static scanning, resonant scanning and hybrid scanning, with dual-axis quasi-static scanning being preferred.

[0050] The permanent magnet 2 is a permanent magnet with strong magnetism and large surface remanence. The material is preferably any one or two of neodymium iron boron and samarium cobalt. The shape is preferably, but not limited to, a cylinder, a cuboid or a prism with a polygonal base, and it is magnetized along the length direction.

[0051] The dual-axis torsion mechanism is a flexible motion mechanism that can achieve scanning along the X and Y axes. In one example, the dual-axis torsion mechanism is a universal joint flexible scanning mechanism with independent dual-axis torsion. The torsional stiffness of the two axes is preferably equal to that of each other. The material is preferably single-crystal silicon, and it is preferably processed by MEMS technology.

[0052] In further examples, such as Figure 3 As shown, the dual-axis torsion mechanism includes a support platform 31 for supporting a permanent magnet, which is connected to the moving part of the dual-axis torsion mechanism. A through hole is provided in the middle (usually the center) of the support platform 31. The two vertical torsion axes of the dual-axis torsion mechanism intersect at the torsion center and are located at the center of the through hole. The permanent magnet 2 is inserted from the center of the through hole and connected to the support platform 31. Preferably, the permanent magnet 2 and the support platform 31 are glued together. The connection and fixing position of the permanent magnet 2 and the support platform 31 is the position where the center of mass of the permanent magnet 2 coincides with the torsion center of the dual-axis torsion mechanism, so as to realize the near-pure torque torsion drive of the permanent magnet.

[0053] In a further example, the dual-axis torsion mechanism also includes an integrated angle sensor (not shown) for real-time measurement of the dual-axis scanning angle. The integrated angle sensor includes, but is not limited to, any one of a piezoresistive sensor, a capacitive sensor, a piezoelectric sensor, and an electromagnetic sensor, preferably a piezoresistive sensor or a capacitive sensor.

[0054] As an example, such as Figure 7-9 As shown, the driving electromagnet 5 includes an iron core 51 and a coil 52. The iron core 51 is made of a soft magnetic material and includes connected air gap magnetic poles 511, a magnetically conductive portion 512, and a magnetically conductive base plate 513. The soft magnetic material is preferably, but not limited to, permalloy with low hysteresis and high permeability. The coil 52 is made of wire with an insulating surface layer and is wound around the magnetically conductive portion 512 of the iron core 51. Under the excitation of the driving current, the coil 52 generates a driving magnetic field with controllable magnetic field strength. The driving magnetic field passes through the air gap magnetic poles 511, the magnetically conductive portion 512, and the magnetically conductive base plate 513 of the iron core 51 and forms a closed magnetic circuit with the air gap of the electromagnet.

[0055] In a further example, the air gap magnetic pole 511 in the iron core 51 is perpendicular to the magnetically conductive portion 512, and the air gap magnetic pole 511 includes chamfered corners or arc-shaped chamfers to provide space for the movement of the optical mirror 1; the magnetically conductive portion 512 in the iron core 51 is perpendicular to the plane where the outer frame of the dual-axis torsion mechanism is located and perpendicular to the magnetically conductive base plate, and is magnetically and mechanically connected to the magnetically conductive base plate, preferably by adhesive bonding.

[0056] In one example, the magnetic field within the air gap magnetic pole 511 is composed of the electromagnet magnetic field generated by the driving electromagnet 5 and the permanent magnet 2 magnetic field generated by the remanent magnetic moment of the permanent magnet 2; the distance between any two air gap magnetic poles 511 of the driving electromagnet 5 is less than the distance between the magnetically conductive portions 512 of the driving electromagnet 5; most of the electromagnet magnetic field in free space is concentrated in the air gap of the electromagnet in the closed magnetic circuit; the magnetic field direction of the electromagnet magnetic field in the air gap is perpendicular to the initial position of the permanent magnet 2 before deflection, and rotates in a plane perpendicular to the permanent magnet 2 as the multiple driving currents of the driving electromagnet 5 change; the direction of the driving torque is determined by the vector product τ = M × B, where B is the driving magnetic field generated by the driving electromagnet 5 and M is the magnetic moment of the permanent magnet 2.

[0057] In a further example, each driving core 51 of the driving electromagnet 5 is wound with a set of coarse modulation coils with many turns and a set of fine modulation coils with few turns (the fine modulation coils have fewer turns than the coarse modulation coils). The coarse modulation coils enable large-angle scanning control of the optical scanning mirror, and the fine modulation coils enable precise and rapid control of the driving magnetic field.

[0058] The concealed drive structure refers to the fact that the dual-axis torsion mechanism is blocked by the optical mirror 1. Only the optical mirror 1 can be seen on the surface of the moving magnet electromagnetic drive dual-axis optical scanning mirror, which can obtain a high optical duty cycle, preferably greater than 50%.

[0059] like Figure 13 As shown, the present invention also provides a moving-magnetic electromagnetically driven dual-axis optical scanning mirror array, which includes multiple (three or more) moving-magnetic electromagnetically driven dual-axis optical scanning mirrors 100 as described in any of the above embodiments, and the multiple moving-magnetic electromagnetically driven dual-axis optical scanning mirrors 100 are arranged in an array in the same plane. For a more detailed description of the moving-magnetic electromagnetically driven dual-axis optical scanning mirror, please refer to the foregoing content; for the sake of brevity, it will not be repeated. Due to the use of the aforementioned moving-magnetic electromagnetically driven dual-axis optical scanning mirror, the moving-magnetic electromagnetically driven dual-axis optical scanning mirror array provided by the present invention also has the advantages of achieving large mirror size and large-angle scanning.

[0060] As an example, the planar arrangement of the plurality of moving-magnetic-driven dual-axis optical scanning mirrors 100 includes any one of regular quadrilaterals, regular hexagons, and equilateral triangles, preferably a regular quadrilateral arrangement, forming an m×n array, where m and n are positive integers greater than or equal to 2. Furthermore, the plurality of moving-magnetic-driven dual-axis optical scanning mirrors are preferably mass-produced using MEMS technology and micro-assembled and packaged in an array to ensure good consistency of the moving-magnetic-driven dual-axis optical scanning mirror array.

[0061] In one example, a magnetic shielding frame (not shown) is provided between adjacent moving-magnetic-driven biaxial optical scanning mirrors to reduce magnetic crosstalk between the optical scanning mirrors. The magnetic shielding frame is preferably made of a soft magnetic material, such as stainless steel.

[0062] The present invention also provides an application of the moving-magnetic electromagnetic drive dual-axis optical scanning mirror or the array of the moving-magnetic electromagnetic drive dual-axis optical scanning mirror as described in any of the above embodiments. The moving-magnetic electromagnetic drive dual-axis optical scanning mirror or array is applied to any one of laser phased array, laser communication, lidar and laser weapon. That is, a single moving-magnetic electromagnetic drive dual-axis optical scanning mirror can be used at a time, or multiple moving-magnetic electromagnetic drive dual-axis optical scanning mirrors can be used simultaneously. The specific application depends on the application requirements and is not strictly limited thereto.

[0063] To further highlight the technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0064] Example 1

[0065] like Figure 1 As shown, this embodiment provides a moving-magnet type electromagnetically driven dual-axis optical scanning mirror, specifically a two-dimensional electromagnetically driven optical scanning mirror with its torsion center located at the center of mass of a permanent magnet. Its structure includes an optical mirror 1, a permanent magnet 2, a universal joint 3 serving as a dual-axis torsion mechanism, and a driving electromagnet 5. The moving-magnet type electromagnetically driven dual-axis optical scanning mirror may further include an encapsulation structure 4 to facilitate the connection and fixation of each structure. (Reference) Figure 1 Optical mirror 1 is made of single-crystal silicon processed using MEMS technology, with a diameter of 10mm. The surface of optical mirror 1 is gold-plated, with a surface roughness of ≤2nm, and has a high reflectivity of greater than 97% in the mid-infrared band.

[0066] Figure 2 yes Figure 1 An exploded view of the structure shown. See also Figure 2The permanent magnet 2 is disposed below the optical mirror 1. One of the magnetic poles of the permanent magnet 2 is fixed to the optical mirror 1 by adhesive. The polarization direction of the permanent magnet 2 is perpendicular to the mirror. In this embodiment, the permanent magnet 2 has dimensions of 3×1×1mm, with the 3mm height direction being the polarization magnetization direction. The permanent magnet 2 is made of neodymium iron boron material with a remanence of 1.2 Tesla.

[0067] See Figure 2 and Figure 3 The universal joint 3 is a flexible motion mechanism that can rotate independently on two axes, connecting the permanent magnet 2 and the encapsulation structure 4. The permanent magnet support platform 31 of the universal joint 3 is connected to the center of the permanent magnet 2. The universal joint outer frame 32 is connected to the encapsulation structure 4, and the universal joint outer frame 32 and the support platform 31 are connected by two pairs of orthogonal flexible single-crystal silicon torsion beams 33. Thus, under the torque generated by the permanent magnet 2, rotation is generated in two dimensions: azimuth angle and deflection angle. During rotation, the torsion center of the universal joint 3 coincides with the center of mass of the permanent magnet 2.

[0068] In this embodiment, the universal joint 3 is fabricated from a silicon wafer using MEMS technology, achieving sub-micron level processing precision. The main processes are photolithography and deep silicon etching. The universal joint 3 comprises two pairs of flexible torsion beams placed horizontally and vertically. The flexible torsion beams have a length L of 1200 μm, a width of 25 μm, and a height of 250 μm. The torsional stiffness of the two flexible torsion beams in the azimuth and pitch dimensions is 10. -4 A torque on the order of N·m / rad and tens of μN·m can drive a pair of flexible torsion beams to twist a mechanical angle of 15°. The vertical stiffness Kz of the elastic beam in the vertical direction is on the order of 104 N / m. The large stiffness Kz keeps the change in the rotation center position of the universal joint extremely small when it rotates in different directions and angles. This ensures that the torsion center of the universal joint and the center of mass of the permanent magnet always coincide under different torsion states. At the same time, it can also improve the scanning mirror's ability to resist vertical vibration and impact.

[0069] The distance S between the optical mirror 1 and the gimbal frame 32 satisfies the space requirements for large-angle deflection of the optical mirror, meaning that the optical mirror cannot collide with the gimbal in any scanning state. In this embodiment, the diameter of the optical mirror is 10mm, and a vertical height space of (10mm / 2)*sin(15°)≈1.294mm is required when deflecting a mechanical angle of 15°. The vertical height is set to 1.35mm.

[0070] See Figure 4The encapsulation structure 4 includes an encapsulation shell 41 and a soft magnetic base plate 42. The encapsulation shell 41 is formed by machining a metal block, and the soft magnetic base plate 42 is formed by machining a soft magnetic material. In this embodiment, the encapsulation shell 41 is made of No. 45 steel and has a height of 23mm. The soft magnetic base plate 42 is formed by machining 1J85 permalloy material with a thickness of 4mm.

[0071] The encapsulation housing 41 is connected to the outside of the universal joint 3 to provide support for the outside of the universal joint and to form the basis for the torsional movement of the inside of the universal joint, the permanent magnet and the mirror system.

[0072] See Figure 5 and Figure 6 The optical scanning mirror proposed in this embodiment includes four driving electromagnets 5, which are mounted on a soft magnetic base plate 42.

[0073] See Figure 7 and Figure 8 The driving electromagnet 5 includes an iron core 51 and a coil 52.

[0074] See Figure 9 The iron core 51 is made of soft magnetic material and includes an air gap magnetic pole 511, a magnetically conductive part 512, and a magnetically conductive base plate 513. The coil 52 is wound around the magnetically conductive part 512 of the iron core 51. The coil 52 generates a magnetic field of variable intensity under different current excitation and conducts it through the magnetically conductive part 512. In this embodiment, the coil uses enameled copper wire with a wire diameter of 0.1mm, 800 turns, an input current of 50mA, and a magnetically conductive part length of 14mm. The air gap magnetic pole 511 is located at one end of the magnetically conductive part. The air gap magnetic poles 511 of the four driving electromagnets together form the air gap of the electromagnet. The permanent magnet 2 is located in the air gap of the electromagnet. The magnetic field of the driving permanent magnet is obtained by synthesizing the air gap magnetic fields of the four driving electromagnets. The direction and amplitude of the magnetic field are controlled by controlling the magnitude and direction of the driving current of the coils on the four driving electromagnets.

[0075] See Figure 10 The distance g between the two air gap magnetic poles 511 is less than the distance between the magnetically conductive parts 512. In this embodiment, the magnetically conductive parts 512 are placed vertically, the air gap magnetic poles 511 are placed horizontally, the distance between the paired air gap magnetic poles 511 is 2.6 mm, and the distance between the magnetically conductive parts 512 is 7 mm.

[0076] The cross-section of the air gap magnetic pole 511 is parallel to the initial position of the permanent magnet at 0 degrees, and the height of the cross-section of the air gap magnetic pole 511 is slightly smaller than the height of the permanent magnet 2 in the magnetic pole direction. In this embodiment, the height of the air gap magnetic pole cross-section is 2.6 mm, the width is 1 mm, the height of the permanent magnet 2 on the magnetic pole is 3 mm, and the midpoint of the height of the air gap magnetic pole 511 cross-section has the same coordinates as the midpoint of the height of the permanent magnet 2 in the vertical position. The magnetic field generated by the driving electromagnet passes through the cross-section of the air gap magnetic pole, forming an adjustable magnetic field between the air gap magnetic pole cross-sections, and driving the permanent magnet to output torque.

[0077] The space between the air gap magnetic poles 511 satisfies the motion space required for the permanent magnet to twist at two large angles. In this embodiment, the space required for a permanent magnet with a distance of 2.6 mm between the air gap magnetic poles 511, a height of 3 mm, and a cross-section of 1 mm × 1 mm to twist 15 degrees around its center of mass is less than (3 mm / 2)*sin(15°)*2 + 0.5 mm*2 ≈ 1.78 mm.

[0078] like Figure 3 As shown, the air gap magnetic pole 511 of the driving electromagnet 5 is located in the through-hole space inside the permanent magnet support platform of the universal joint. The size of the through-hole meets the requirement that it does not contact the driving electromagnet when the universal joint rotates at a large angle. In this embodiment, the through-hole is fan-shaped, and the four fan-shaped through-holes provide space for the four driving electromagnets. The inner diameter of the fan is 1mm and the outer diameter is 3.8mm.

[0079] The magnetic base plate 513 is mounted on the soft magnetic base plate 42 to form a closed magnetic circuit and reduce the magnetic resistance of the magnetic circuit.

[0080] In this embodiment, the relative positions of the universal joint 3 and the driving electromagnet 5 are defined by the encapsulation structure 4. In this embodiment, the universal joint 3 is connected to the encapsulation housing 41, the driving electromagnet 5 is connected to the soft magnetic base plate 42, and the encapsulation housing 41 and the soft magnetic base plate 42 are connected by screws and screw holes.

[0081] Example 2

[0082] This embodiment provides another structure of a moving-magnet electromagnetically driven biaxial optical scanning mirror, which is also a two-dimensional electromagnetically driven optical scanning mirror with its torsion center located at the center of mass of the permanent magnet. Its structure includes an optical mirror 1, a permanent magnet 2, a universal joint 3, a packaging structure 4, and an electromagnet 5. The structures of the optical mirror 1, the permanent magnet 2, and the packaging structure 4 are the same as in Embodiment 1, and their structures are referenced. Figure 1 and Figure 2 .

[0083] See Figure 11 The optical scanning mirror in this embodiment includes three driving electromagnets 5, which are mounted on a soft magnetic base plate 42.

[0084] See Figure 12 The universal joint 3 of the optical scanning mirror in this embodiment includes a platform for the permanent magnet, which includes an active space for three driving electromagnets.

[0085] The moving-magnetic electromagnetically driven dual-axis optical scanning mirror provided in this embodiment includes only three driving electromagnets, while the moving-magnetic electromagnetically driven dual-axis optical scanning mirror provided in Embodiment 1 includes four driving electromagnets. Apart from this difference, the other structures of the moving-magnetic electromagnetically driven dual-axis optical scanning mirror in this embodiment, including the materials and dimensions of each structure, are the same as in Embodiment 1. Please refer to the description of Embodiment 1 for details; for the sake of brevity, further elaboration is omitted.

[0086] Example 3

[0087] like Figure 13 As shown, this embodiment provides a moving-magnetic electromagnetically driven dual-axis optical scanning mirror array. This electromagnetically driven two-dimensional optical scanning mirror array based on a synthetic rotating magnetic field is composed of electromagnetically driven two-dimensional optical scanning mirrors arranged in a 4×4 array, that is, multiple moving-magnetic electromagnetically driven dual-axis optical scanning mirrors 100 as described in any one of Embodiments 1 or 2 are arranged in an array. Therefore, the foregoing content can be quoted in its entirety here, and will not be repeated for the purpose of brevity.

[0088] like Figure 14 As shown, in another example, the moving-magnetic electromagnetic drive dual-axis optical scanning mirror array is composed of multiple moving-magnetic electromagnetic drive dual-axis optical scanning mirrors 100 as described in any one of Embodiments 1 or 2, arranged in a 7-tuple array configuration.

[0089] In summary, this invention provides a moving-magnet type electromagnetically driven dual-axis optical scanning mirror, array, and its application. The optical scanning mirror includes an optical mirror, a permanent magnet, a dual-axis torsion mechanism, and a driving electromagnet. The optical mirror is connected to one end of the permanent magnet, and the permanent magnet is connected to the dual-axis torsion mechanism in the middle. The driving magnetic field generated by the driving electromagnet intersects with the magnetic moment of the permanent magnet, causing the permanent magnet to undergo torsional motion under the action of electromagnetic torque. The optical mirror is located above the dual-axis torsion mechanism, and the planes on which they lie are parallel to each other. The vertical distance between them satisfies the spatial requirements for the optical mirror to rotate within the maximum scanning angle, thus forming a concealed driving structure. The driving electromagnet includes three or more air-gap magnetic poles, which are symmetrically distributed. The air gap between the air gap magnetic poles forms an electromagnet air gap, and the permanent magnet is located in the middle of the electromagnet air gap, typically at the exact center of the air gap. The size of the electromagnet air gap satisfies the spatial requirements for the permanent magnet to rotate within the maximum scanning angle. This invention enables large mirror size, independent dual-axis scanning, and wide-angle scanning. Furthermore, the dual axes can simultaneously achieve quasi-static scanning, greatly simplifying the drive control algorithm of the electromagnetic actuator and allowing for the construction of a high duty cycle scanning mirror array. The moving-magnetic-driven dual-axis optical scanning mirror provided by this invention can be applied to any of the following: laser phased arrays, laser communication, lidar, and laser weapons. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and possesses high industrial applicability.

[0090] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A moving-magnet type electromagnetically driven dual-axis optical scanning mirror, characterized in that, The system includes an optical mirror, a permanent magnet, a dual-axis torsion mechanism, and a driving electromagnet. The optical mirror is connected to the permanent magnet, which is connected in the middle to the dual-axis torsion mechanism. The driving magnetic field generated by the driving electromagnet intersects with the magnetic moment of the permanent magnet, causing the permanent magnet to undergo torsional motion under the action of electromagnetic torque. The dual-axis torsion mechanism is a dual-axis independent torsion universal joint flexible scanning mechanism with equal torsional stiffness on both axes. The dual-axis torsion mechanism includes a support platform for supporting the permanent magnet. The connection and fixed position between the permanent magnet and the support platform is such that the center of mass of the permanent magnet coincides with the torsion center of the dual-axis torsion mechanism. The torsion center of the dual-axis torsion mechanism and the center of mass of the permanent magnet always coincide under different torsion states to achieve near-pure torque torsion drive of the permanent magnet. The optical mirror is located above the dual-axis torsion mechanism. The planes on which the two are located are parallel to each other, and the vertical distance between them meets the spatial requirements when the optical mirror rotates within the maximum scanning angle, thus forming a hidden drive structure. The driving electromagnet includes three or more air gap magnetic poles, which are symmetrically distributed. The air gap magnetic poles form an electromagnet air gap in the middle, and the permanent magnet is located in the middle of the electromagnet air gap. The size of the electromagnet air gap meets the space requirements for the permanent magnet to rotate within the maximum scanning angle. The driving electromagnet includes an iron core and a coil. The iron core includes connected air gap magnetic poles, a magnetically conductive part, and a magnetically conductive base plate. The magnetic field within the air gap magnetic pole is composed of the electromagnet magnetic field generated by the driving electromagnet and the permanent magnet magnetic field generated by the remanent magnetic moment of the permanent magnet; the distance between any two air gap magnetic poles of the driving electromagnet is less than the distance between the magnetically conductive parts of the driving electromagnet; the direction of the electromagnet magnetic field within the air gap is perpendicular to the initial position of the permanent magnet before deflection, and rotates in a plane perpendicular to the permanent magnet as the multiple driving currents of the driving electromagnet change; the direction of the driving torque is determined by the vector product τ = M×B, where B is the driving magnetic field generated by the driving electromagnet and M is the magnetic moment of the permanent magnet.

2. The moving-magnetic-driven dual-axis optical scanning mirror according to claim 1, characterized in that, The optical mirror includes an optical reflector made of monocrystalline silicon and aluminum, with an optical reflective film coated on its surface. The mirror shape includes one of the following: a circle, an ellipse, a square, a rectangle, and a regular hexagon with central symmetry.

3. The moving-magnetic-driven dual-axis optical scanning mirror according to claim 1, characterized in that, The back of the optical mirror is designed with a hollow structure and a support connection structure, and is connected to one end of the permanent magnet through the support connection structure.

4. The moving-magnetic-driven dual-axis optical scanning mirror according to claim 3, characterized in that, The supporting connection structure of the optical mirror is connected to the permanent magnet through low-stress adhesive.

5. The moving-magnetic-driven dual-axis optical scanning mirror according to claim 1, characterized in that, The mirror size of the optical mirror is 2mm-50mm.

6. The moving-magnetic-driven dual-axis optical scanning mirror according to claim 1, characterized in that, The optical angle scanning range of the moving magnet type electromagnetic drive dual-axis optical scanning mirror is -60° to 60°, and the scanning mode includes any one of quasi-static scanning, resonant scanning and hybrid scanning.

7. The moving-magnetic-driven dual-axis optical scanning mirror according to claim 1, characterized in that, The permanent magnet is made of any one or two of neodymium iron boron and samarium cobalt, and its shape includes any one of cylindrical, cuboid and polygonal prism, and is magnetized along its length.

8. The moving-magnetic-driven dual-axis optical scanning mirror according to claim 1, characterized in that, The biaxial torsion mechanism is made of monocrystalline silicon and is fabricated using MEMS technology.

9. The moving-magnetic-driven dual-axis optical scanning mirror according to claim 8, characterized in that, The dual-axis torsion mechanism includes a support platform for supporting permanent magnets, which is connected to the moving part of the dual-axis torsion mechanism. The support platform has a through hole in the middle. The two vertical torsion axes of the dual-axis torsion mechanism intersect at the torsion center and are located at the center of the through hole. The permanent magnet is inserted from the center of the through hole and connected to the support platform.

10. The moving-magnetic-driven dual-axis optical scanning mirror according to claim 9, characterized in that, The permanent magnet is bonded to the support platform with adhesive.

11. The moving-magnetic-driven dual-axis optical scanning mirror according to claim 1, characterized in that, The dual-axis torsion mechanism also includes an integrated angle sensor for real-time measurement of the dual-axis scanning angle. The integrated angle sensor includes any one of a piezoresistive sensor, a capacitive sensor, a piezoelectric sensor, and an electromagnetic sensor.

12. The moving-magnetic-driven dual-axis optical scanning mirror according to claim 1, characterized in that, The iron core is made of a soft magnetic material, including permalloy; the coil is made of a wire with an insulating surface layer and is wound around the magnetically conductive portion of the iron core. The coil generates a controllable driving magnetic field under the excitation of the driving current. The driving magnetic field passes through the air gap magnetic pole, the magnetic conductive part and the magnetic conductive base plate of the iron core, and forms a closed magnetic circuit with the air gap of the electromagnet.

13. The moving-magnetic-driven dual-axis optical scanning mirror according to claim 12, characterized in that, The air gap magnetic pole in the iron core is perpendicular to the magnetically conductive part, and the air gap magnetic pole includes a chamfer or an arc-shaped chamfer to provide space for the movement of the optical mirror; the magnetically conductive part in the iron core is perpendicular to the plane where the outer frame of the dual-axis torsion mechanism is located and perpendicular to the magnetically conductive base plate, and is magnetically and mechanically connected to the magnetically conductive base plate.

14. The moving-magnetic-driven dual-axis optical scanning mirror according to claim 1, characterized in that, The driving electromagnet has a set of coarse modulation coils with many turns and a set of fine modulation coils with few turns wound on each driving core. The coarse modulation coils enable large-angle scanning control of the optical scanning mirror, and the fine modulation coils enable precise and rapid control of the driving magnetic field.

15. A moving-magnetic-driven dual-axis optical scanning mirror array, characterized in that, The moving-magnetic electromagnetic drive dual-axis optical scanning mirror array includes a plurality of moving-magnetic electromagnetic drive dual-axis optical scanning mirrors as described in any one of claims 1-14, and the plurality of moving-magnetic electromagnetic drive dual-axis optical scanning mirrors are arranged in an array in the same plane.

16. The moving-magnetic-driven dual-axis optical scanning mirror array according to claim 15, characterized in that, The planar arrangement of the plurality of moving magnet type electromagnetically driven biaxial optical scanning mirrors includes any one of a regular quadrilateral, a regular hexagon, and an equilateral triangle.

17. The moving-magnetic-driven dual-axis optical scanning mirror array according to claim 15, characterized in that, A magnetic shielding frame for reducing magnetic crosstalk is provided between adjacent moving-magnetic-driven dual-axis optical scanning mirrors. The magnetic shielding frame is made of soft magnetic material.

18. An application of a moving-magnet electromagnetically driven biaxial optical scanning mirror as described in any one of claims 1-14 or an array of moving-magnet electromagnetically driven biaxial optical scanning mirrors as described in any one of claims 15-17, characterized in that, The moving-magnetic electromagnetic drive dual-axis optical scanning mirror or the moving-magnetic electromagnetic drive dual-axis optical scanning mirror array can be applied to any one of laser phased arrays, laser communication, lidar, and laser weapons.

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