A magnetic circuit module, a micro-electro-mechanical system rotating mirror and a laser communication terminal

Abstract

The application relates to the field of micro-electro-mechanical systems, and discloses a magnetic circuit module, a micro-electro-mechanical system rotating mirror and a laser communication terminal. The magnetic circuit module comprises a first magnetic yoke, a permanent magnet and a second magnetic yoke; the first magnetic yoke comprises a first end face and a second end face, and the second magnetic yoke comprises a third end face and a fourth end face; the first end face is connected with a first magnetic pole of the permanent magnet, and the third end face is connected with a second magnetic pole of the permanent magnet; the second end face and the fourth end face are opposite and used for forming an air gap; the area of the second end face is smaller than the area of the first end face; and / or the area of the fourth end face is smaller than the area of the third end face. According to the embodiment of the application, the magnetic flux density at the second end face and / or the fourth end face with a smaller area can be obviously improved, so that the magnetic flux density in the air gap is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro-electro-mechanical systems, and in particular to a magnetic circuit module, a micro-electro-mechanical system rotating mirror and a laser communication terminal. BACKGROUND

[0002] The manufacturing capability of micro-electro-mechanical system (MEMS) microfabrication technology has greatly improved, the cost of single-piece manufacturing has greatly reduced, and the size of the device has been reduced by orders of magnitude. The ability to manufacture optical devices has made a great leap. The devices manufactured by micro-electro-mechanical systems can achieve from sub-micron, micron to millimeter or even centimeter size, which is a very promising technology.

[0003] The millimeter-scale devices made by MEMS microfabrication technology not only inherit the large aperture, high gain and other characteristic advantages of large-size devices, but also take advantage of the low inertia, low power consumption and consistency and batch production of the manufacturing process of MEMS devices. In addition to improving the performance of the device, the cost of the device is greatly reduced. A typical large-size optical MEMS device is a large-size MEMS optical rotating mirror.

[0004] The driving mode of the optical MEMS rotating mirror is divided into electromagnetic, electrostatic, electrothermal and piezoelectric. Among them, the electromagnetic and piezoelectric driving modes have larger driving force. The electromagnetic driving type MEMS rotating mirror based on the principle of DC motor torque generation has the advantages of high efficiency and no net force.

[0005] Due to the very small size of the MEMS rotating mirror, the principle of DC motor torque generation has difficulties in designing the MEMS rotating mirror in applications with lightweight requirements. SUMMARY

[0006] When the principle of DC motor torque generation is applied to the design of the MEMS rotating mirror with lightweight requirements, there is a large amount of leakage magnetic field in the magnetic circuit of the lack of design scheme, which significantly affects the performance of the magnetic circuit, and it is difficult to generate a strong magnetic field at the air gap where the coil is located, thereby causing a serious leakage magnetic problem. After the leakage magnetic problem occurs, the magnetic flux density in the air gap will be greatly reduced. Based on this, the present application discloses a magnetic circuit module, a micro-electro-mechanical system rotating mirror and a laser communication terminal, which are used to improve the magnetic flux density in the air gap of the magnetic circuit.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0008] In a first aspect, the present application provides a magnetic circuit module, comprising a first magnetic yoke, a permanent magnet and a second magnetic yoke; the first magnetic yoke comprises a first end face and a second end face, and the second magnetic yoke comprises a third end face and a fourth end face; wherein,

[0009] The first end surface is connected with a first magnetic pole of the permanent magnet, and the third end surface is connected with a second magnetic pole of the permanent magnet; the second end surface and the fourth end surface are opposite to each other and are used for forming an air gap;

[0010] The area of the second end surface is smaller than the area of the first end surface; and / or the area of the fourth end surface is smaller than the area of the third end surface.

[0011] The magnetic circuit module comprises a permanent magnet, a first magnetic yoke and a second magnetic yoke. The first end surface of the first magnetic yoke is connected with a first magnetic pole of the permanent magnet, and the third end surface of the second magnetic yoke is connected with a second magnetic pole of the permanent magnet. The second end surface of the first magnetic yoke and the fourth end surface of the second magnetic yoke are used for cooperating to form an air gap. In the first magnetic yoke, the area of the second end surface is designed to be smaller than the area of the first end surface; and / or in the second magnetic yoke, the area of the fourth end surface is designed to be smaller than the area of the third end surface. The permanent magnet provides stable magnetic flux, and the magnetic flux density is inversely proportional to the area of the end surface. The embodiments of the present application can obviously improve the magnetic flux density of the air gap opposite to the second end surface and / or the fourth end surface with a smaller area, thereby improving the magnetic flux density in the air gap.

[0012] In some embodiments, the first end surface and the second end surface are both arc surfaces; the first end surface and the second end surface are arranged along the axial direction of the arc surface, the radius of the first end surface is smaller than the radius of the second end surface, and the axial dimension of the first end surface is greater than the axial dimension of the second end surface;

[0013] And / or, the third end surface and the fourth end surface are both arc surfaces; the third end surface and the fourth end surface are arranged along the axial direction of the arc surface, the radius of the third end surface is greater than the radius of the fourth end surface, and the axial dimension of the third end surface is greater than the axial dimension of the fourth end surface.

[0014] In some embodiments, the first magnetic yoke comprises a first segment and a second segment; the first segment comprises the first end surface, and the second segment comprises the second end surface; along the radial direction of the arc surface, the second segment is located on the side of the first segment facing the second magnetic yoke;

[0015] And / or, the second magnetic yoke comprises a third segment and a fourth segment; the third segment comprises the third end surface, and the fourth segment comprises the fourth end surface; the fourth segment is located on the side of the third segment facing the first magnetic yoke.

[0016] In some embodiments, the first magnetic yoke further comprises at least one first intermediate segment, the at least one first intermediate segment is connected between the first segment and the second segment; and along the axial direction of the arc surface, the thickness of the at least one first intermediate segment is smaller than the thickness of the first segment, and the thickness of the at least one first intermediate segment is greater than the thickness of the second segment;

[0017] And / or, the second yoke further comprises at least one second intermediate section, the at least one second intermediate section is connected between the third section and the fourth section; and in the axial direction of the arc surface, the thickness of the at least one second intermediate section is less than the thickness of the third section, and the thickness of the at least one second intermediate section is greater than the thickness of the fourth section.

[0018] In some embodiments, the first intermediate section is a plurality, and the plurality of first intermediate sections are arranged in the direction from the first section to the second section; in the direction from the first section to the second section, the thickness of the first intermediate section close to the second section is less than the thickness of the first intermediate section close to the first section;

[0019] And / or, the second intermediate section is a plurality, and the plurality of second intermediate sections are arranged in the direction from the third section to the fourth section; in the direction from the third section to the fourth section, the thickness of the second intermediate section close to the fourth section is less than the thickness of the second intermediate section close to the third section.

[0020] In some embodiments, the first intermediate section is a plurality, and the plurality of first intermediate sections are arranged in the direction from the first section to the second section; in the direction from the first section to the second section, the thickness of the plurality of first intermediate sections gradually decreases;

[0021] And / or, the second intermediate section is a plurality, and the plurality of second intermediate sections are arranged in the direction from the third section to the fourth section; in the direction from the third section to the fourth section, the thickness of the plurality of second intermediate sections gradually decreases.

[0022] In a second aspect, the embodiments of the present application further provide a micro-electro-mechanical system (MEMS) mirror, comprising the magnetic circuit module according to any one of the first aspect; the micro-electro-mechanical system mirror further comprises:

[0023] A mirror chip, comprising an outer frame, a flexible beam, a coil frame and a mirror surface; the outer frame is fixed to the magnetic circuit module; the coil frame is connected between the mirror surface and the outer frame, and the coil frame surrounds the mirror surface, and the outer frame surrounds the coil frame; one end of the flexible beam is connected to the coil frame, and the other end is connected to the outer frame;

[0024] A coil assembly, fixed to the coil frame and located in the air gap.

[0025] In some embodiments, the magnetic circuit module is two, and the two magnetic circuit modules are symmetrically arranged on both sides of the mirror surface.

[0026] In some embodiments, the micro-electro-mechanical system mirror further comprises a base; the magnetic circuit module is fixed to the base.

[0027] In a third aspect, the embodiments of the present application further provide a micro-electro-mechanical system (MEMS) mirror, comprising the magnetic circuit module according to any one of the first aspect; the magnetic circuit module comprises an inner shaft magnetic circuit module and an outer shaft magnetic circuit module, the inner shaft magnetic circuit module forms a first air gap, and the outer shaft magnetic circuit module forms a second air gap.

[0028] The micro-electro-mechanical system mirror further comprises:

[0029] The mirror chip comprises an outer frame, an outer shaft flexible beam, an outer shaft coil frame, an inner shaft flexible beam, an inner shaft coil frame and a mirror surface; the outer frame is fixed to the magnetic circuit module; the inner shaft coil frame and the outer shaft coil frame are connected between the mirror surface and the outer frame, the inner shaft coil frame surrounds the mirror surface, the outer shaft coil frame surrounds the inner shaft coil frame, and the outer frame surrounds the outer shaft coil frame; one end of the inner shaft flexible beam is connected to the inner shaft coil frame, and the other end is connected to the outer shaft coil frame; one end of the outer shaft flexible beam is connected to the outer shaft coil frame, and the other end is connected to the outer frame; the extension direction of the inner shaft flexible beam intersects with the extension direction of the outer shaft flexible beam.

[0030] The coil assembly comprises an inner shaft coil and an outer shaft coil; the inner shaft coil is fixed to the inner shaft coil frame and located in the first air gap; and the outer shaft coil is fixed to the outer shaft coil frame and located in the second air gap.

[0031] In some embodiments, the micro-electro-mechanical system mirror further comprises a base; and the magnetic circuit module is fixed to the base.

[0032] In a fourth aspect, the embodiments of the present application further provide a laser communication terminal comprising the micro-electro-mechanical system mirror according to any one of the second aspect.

[0033] In a fifth aspect, the embodiments of the present application further provide a laser communication terminal comprising the micro-electro-mechanical system mirror according to any one of the third aspect. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is a schematic diagram of the working principle of a direct current motor;

[0035] Figure 2 It is a schematic diagram of the structure of a micro-electro-mechanical system mirror provided by the embodiments of the present application;

[0036] Figure 3 It is an exploded view of a micro-electro-mechanical system mirror provided by the embodiments of the present application;

[0037] Figure 4 It is a schematic diagram of the structure of a mirror chip in a micro-electro-mechanical system mirror provided by the embodiments of the present application;

[0038] Figure 5A structure diagram of a magnetic circuit module in a micro-electro-mechanical system rotating mirror is provided for an embodiment of the present application.

[0039] Figure 6 A structure diagram of a second magnetic yoke in a micro-electro-mechanical system rotating mirror is provided for an embodiment of the present application.

[0040] Figure 7 A structure diagram of a first magnetic yoke in a micro-electro-mechanical system rotating mirror is provided for an embodiment of the present application.

[0041] Figure 8 A structure diagram of another micro-electro-mechanical system rotating mirror is provided for an embodiment of the present application.

[0042] Figure 9 An exploded view of another micro-electro-mechanical system rotating mirror is provided for an embodiment of the present application.

[0043] Figure 10 A structure diagram of another magnetic circuit module in a micro-electro-mechanical system rotating mirror is provided for an embodiment of the present application.

[0044] Figure 11 A disassembled diagram of a rotating mirror chip and a coil assembly in another micro-electro-mechanical system rotating mirror is provided for an embodiment of the present application.

[0045] Figure 12 A structure diagram of an outer shaft magnetic circuit module in another micro-electro-mechanical system rotating mirror is provided for an embodiment of the present application.

[0046] Figure 13 A structure diagram of a second magnetic yoke of an outer shaft magnetic circuit module in another micro-electro-mechanical system rotating mirror is provided for an embodiment of the present application.

[0047] Figure 14 A structure diagram of a first magnetic yoke of an outer shaft magnetic circuit module in another micro-electro-mechanical system rotating mirror is provided for an embodiment of the present application.

[0048] Figure 15 A structure diagram of a first magnetic yoke of an inner shaft magnetic circuit module in another micro-electro-mechanical system rotating mirror is provided for an embodiment of the present application.

[0049] Figure 16 A structure diagram of a second magnetic yoke of an inner shaft magnetic circuit module in another micro-electro-mechanical system rotating mirror is provided for an embodiment of the present application.

[0050] Figure 17 A structure diagram of a laser communication terminal is provided for an embodiment of the present application.

[0051] Icons: 100-Rotating mirror chip; 200-Coil assembly; 300-Magnetic circuit module; 400-Base; 300a-Magnetic circuit module; 300b-Magnetic circuit module; 110-Outer frame; 120-Flexible beam; 130-Coil frame; 140-Mirror surface; 121-Inner shaft flexible beam; 122-Outer shaft flexible beam; 131-Inner shaft coil frame; 132-Outer shaft coil frame; 210-Inner shaft coil; 220-Outer shaft coil; 301-Inner shaft magnetic circuit module; 302 - Outer shaft magnetic circuit module; 310- First yoke; 320- Permanent magnet; 330- Second yoke; 311- First segment; 312- Second segment; 331- Third segment; 332- Fourth segment; 333- Second intermediate segment; 3021- Positioning boss; 3111- First end face; 3121- Second end face; 3311- Third end face; 3321- Fourth end face; 301a- Inner shaft magnetic circuit module; 301b- Inner shaft magnetic circuit module; 302a- Outer shaft magnetic circuit module; 30 2b - External shaft magnetic circuit module; 310a - First yoke; 320a - Permanent magnet; 330a - Second yoke; 311a - First segment; 312a - Second segment; 313a - First intermediate segment; 331a - Third segment; 332a - Fourth segment; 3111a - First end face; 3121a - Second end face; 3311a - Third end face; 3321a - Fourth end face; 310b - First yoke; 320b - Permanent magnet; 330b - Second yoke; 311b - First segment; 312b - Second segment; 331b - Third segment; 332b - Fourth segment; 333b - Second intermediate segment; 3111b - First end face; 3121b - Second end face; 3311b - Third end face; 3321b - Fourth end face; 01 - Signal / beacon laser source; 02 - Advanced aiming unit; 03 - Transmit / receive beam combining unit; 04 - Fine tracking fast-reflection mirror; 05 - Acquisition and tracking module; 06 - Relay optical path; 07 - Coarse tracking mechanism; 08 - Transmit / receive telescope. Detailed Implementation

[0052] First, let me introduce the design background of this application: In physics, such as Figure 1 As shown, the working principle of a DC motor is as follows: the coil is in an excitation magnetic field, and torque is generated on both sides of the coil under the action of Ampere's force F. The excitation current at both ends of the coil is I, and the number of turns of the coil is N. On both sides of the center of rotation, a portion of the coil of length L is in the same direction of the excitation magnetic field air gap with magnetic flux density Bg. The Ampere's force on the portion of the coil of length L on one side is F = N × B × I × L. The direction of this Ampere's force F is perpendicular to the direction of the excitation magnetic field, satisfying the left-hand rule of Ampere's force. The distance of the coil in the excitation magnetic field from the center of rotation is R. When the radius of rotation of the coil is perpendicular to the Ampere's force F, the torque generated on both sides of the coil is T = 2 × R × N × Bg × I × L.

[0053] The excitation magnetic field in the air gap can be generated by a permanent magnet. Generally, one end or both ends of the permanent magnet can be externally connected with a magnetic yoke to form a closed magnetic circuit, thereby reducing the magnetic resistance and improving the efficiency. In the magnetic circuit comprising the permanent magnet and the magnetic yokes, it is agreed that the magnetic yoke connected with the N-pole of the permanent magnet is the N-pole magnetic yoke. One end of the N-pole magnetic yoke is connected with the N-pole of the permanent magnet, and the other end is the N-pole air gap end surface. The magnetic yoke connected with the S-pole of the permanent magnet is the S-pole magnetic yoke. One end of the S-pole magnetic yoke is connected with the S-pole of the permanent magnet, and the other end is the S-pole air gap end surface. The length of the air gap is the distance between the N-pole air gap end surface and the S-pole air gap end surface.

[0054] By using the principle of generating torque of a direct current motor, a driving coil of an excitation magnetic circuit can be constructed in a micro-electro-mechanical system (MEMS) mirror to generate torque to drive a mirror surface connected with the coil to rotate. The mirror surface rotates by the torque generated by the coil. A MEMS mirror in which the mirror surface rotates around one rotation axis is referred to as a one-dimensional MEMS mirror, and a MEMS mirror in which the mirror surface rotates around two orthogonal rotation axes is referred to as a two-dimensional MEMS mirror.

[0055] Due to the very small size of the MEMS mirror and the lightweight requirement in some applications, the following difficulties are difficult to overcome when the principle of generating torque of a direct current motor is applied to the design of the MEMS mirror.

[0056] The first difficulty is that the principle will face the problem of magnetic leakage in the magnetic circuit in the design of the MEMS mirror. The size of the MEMS mirror is in the order of millimeters to centimeters, which is very compact. When the magnetic yoke and the permanent magnet form a magnetic circuit, the magnetic lines pass through the air gap, and there is an edge magnetic field. The edge magnetic field is also referred to as a leakage magnetic field. Leakage usually occurs at the closest point between the magnetic pole of the permanent magnet and the opposite air gap end surface. For example, in a magnetic circuit comprising a permanent magnet, an N-pole magnetic yoke and an S-pole magnetic yoke, if the distance between the N-pole of the permanent magnet and the closest point of the S-pole air gap end surface is similar to the length of the air gap, a serious leakage problem will occur. After the leakage problem occurs, the magnetic flux density Bgin the air gap will be greatly reduced. The magnetic circuit lacking a design scheme has a large amount of leakage magnetic field, which significantly affects the performance of the magnetic circuit, making it difficult to generate a strong magnetic field in the air gap where the coil is located, thereby causing a serious leakage problem, or a magnetic circuit leakage problem.

[0057] The second difficulty is that when the principle of the DC motor is applied to the MEMS rotating mirror, there is a contradiction between light weight and increased magnetic resistance and magnetic circuit saturation in the design of the compact magnetic circuit of the MEMS rotating mirror. If a thicker magnetic yoke is used, the magnetic resistance can be reduced, but the size and weight will increase. If a thinner magnetic yoke is used, the space occupied by the magnetic circuit is reduced and the weight is reduced, but the problem of magnetic circuit saturation and the problem of increased magnetic resistance will be caused, resulting in a decrease in the performance of the magnetic circuit. The total magnetic flux provided by the permanent magnet is Φ. The cross-sectional area of the magnetic flux of the magnetic yoke is Ay, the depth is ly, and the thickness is wy, Ay = ly x wy. The cross-sectional area of the permanent magnet is Am, the depth of the cross-section of the permanent magnet is lm, and the thickness is wm, Am = lm x wm. The magnetic flux density in the magnetic yoke is By = Φ / Ay. The saturation magnetic flux density of the soft magnetic yoke made of silicon steel is about 2 Tesla. The working magnetic flux density of the permanent magnet is Bm = Φ / Am. The typical residual magnetization of the permanent magnet made of neodymium iron boron is about 1.2 Tesla, and the typical working magnetic flux density Bm is about 0.8 Tesla. The permanent magnet provides a constant Φ, so By x Ay = Bm x Am. When ly = lm, By x wy = Bm x wm. If the thickness of the magnetic yoke wy = 0.5 mm, wm = 1 mm, and Bm = 1.2 Tesla, according to the above formula, By is greater than 2 Tesla. By greater than 2 Tesla will cause the magnetic yoke to saturate. When the magnetic yoke is in a saturated state, the magnetic resistance will increase a lot, causing a magnetic pressure drop, which will significantly affect the performance of the magnetic circuit, resulting in a significant decrease in the magnetic flux density Bg in the air gap.

[0058] Under the influence of the above factors, the magnetic flux density Bg in the air gap is usually less than 0.5 Tesla. Improving the magnetic field strength of the coil becomes a key difficulty in improving the driving capability of the electromagnetic MEMS drive under the limited size.

[0059] To solve the above problems, the embodiment of the present application provides a micro-electro-mechanical system rotating mirror, which improves the magnetic flux density in the air gap by designing a specific magnetic circuit.

[0060] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor belong to the scope of protection of the present application. In the description of the embodiments of the present application, unless otherwise specified, " / " represents the meaning of or, for example, A / B can represent A or B; "and / or" in the text only describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases of A alone, A and B together, and B alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0061] Hereinafter, the terms "first", "second", "third", "fourth", "fifth", "sixth", "seventh" and "eighth" are merely used for descriptive purposes and cannot be understood as indicating or implying relative importance or implying the number of technical features indicated. Therefore, the features defined with "first", "second", "third", "fourth", "fifth", "sixth", "seventh" and "eighth" can explicitly or implicitly include one or more of the features, and in the description of the embodiments of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0062] In a first aspect, as shown in the accompanying drawings, Figures 2 to 7 The present application provides a micro-electro-mechanical system rotating mirror, comprising a rotating mirror chip 100, a coil assembly 200 and a magnetic circuit module 300.

[0063] The magnetic circuit module 300 comprises a first magnetic yoke 310, a permanent magnet 320 and a second magnetic yoke 330; the first magnetic yoke 310 comprises a first end face 3111 and a second end face 3121, and the second magnetic yoke 330 comprises a third end face 3311 and a fourth end face 3321; wherein,

[0064] The first end face 3111 is connected with a first magnetic pole of the permanent magnet 320, and the third end face 3311 is connected with a second magnetic pole of the permanent magnet 320; the second end face 3121 and the fourth end face 3321 are opposite to each other and used for forming an air gap.

[0065] The area of the second end face 3121 is smaller than the area of the first end face 3111; and / or, the area of the fourth end face 3321 is smaller than the area of the third end face 3311.

[0066] In the above micro-electro-mechanical system rotating mirror, the magnetic circuit module 300 comprises the permanent magnet 320, the first magnetic yoke 310 and the second magnetic yoke 330, wherein the first end face 3111 of the first magnetic yoke 310 is connected with a first magnetic pole of the permanent magnet 320, the third end face 3311 of the second magnetic yoke 330 is connected with a second magnetic pole of the permanent magnet 320, and the polarities of the first magnetic pole and the second magnetic pole are opposite. For example, the first end face 3111 of the first magnetic yoke 310 is connected with an S pole of the permanent magnet 320, and the third end face 3311 of the second magnetic yoke 330 is connected with an N pole of the permanent magnet 320. The second end face 3121 of the first magnetic yoke 310 and the fourth end face 3321 of the second magnetic yoke 330 are used for cooperating to form an air gap. In the first magnetic yoke 310, the area of the second end face 3121 is designed to be smaller than the area of the first end face 3111; and / or, in the second magnetic yoke 330, the area of the fourth end face 3321 is designed to be smaller than the area of the third end face 3311. Since the permanent magnet 320 provides stable magnetic flux, and the magnetic flux density is inversely proportional to the area of the end face, the micro-electro-mechanical system rotating mirror of the present application can obviously improve the magnetic flux density of the air gap opposite to the second end face 3121 and / or the fourth end face 3321 with smaller area, thereby improving the magnetic flux density in the air gap.

[0067] In one embodiment, the occurrence of the edge magnetic field, i.e., the leakage magnetic field, can be effectively reduced by reducing the areas of the second end surface 3121 and the fourth end surface 3321. This is because a smaller end surface area can limit the possibility of magnetic lines leaking from the air gap, thereby increasing the magnetic flux density Bgin the air gap. After reducing the leakage magnetic field, more magnetic lines will concentrate in the air gap, thereby generating a stronger magnetic field at the air gap. This helps to improve the efficiency of the mirror drive. By optimizing the structure of the magnetic circuit module 300, the present embodiment significantly reduces the leakage magnetic field problem, enhances the magnetic field strength in the air gap, and improves the driving efficiency of the mirror. This is of great significance for the use of MEMS mirrors in small and high-precision application scenarios.

[0068] In some embodiments, as shown in Figures 2-4 , the mirror chip 100 includes an outer frame 110, a flexible beam 120, a coil frame 130, and a mirror surface 140; the outer frame 110 is fixed to the magnetic circuit module 300; the coil frame 130 is connected between the mirror surface 140 and the outer frame 110, and the coil frame 130 surrounds the mirror surface 140, and the outer frame 110 surrounds the coil frame 130; one end of the flexible beam 120 is connected to the coil frame 130, and the other end is connected to the outer frame 110; the coil assembly 200 is fixed to the coil frame 130 and located within the magnetic circuit air gap.

[0069] As shown in Figure 2 , and in combination with Figure 4 , the mirror chip 100 is fixed to the magnetic circuit module 300 through the outer frame 110, and the coil frame 130 surrounds the mirror surface 140 and is connected to the flexible beam 120. This design can ensure the precise movement of the mirror surface 140 under the action of the magnetic field. The coil assembly 200 is fixed to the coil frame 130 and located within the air gap, so that the electromagnetic force generated when the current passes through the coil can directly act on the mirror surface 140, realizing precise control of the angle of the mirror surface 140.

[0070] Among them, the design of the flexible beam 120 provides the necessary flexibility and repeatability, allowing the mirror surface 140 to rotate freely within a certain range without friction, greatly improving the reliability of the mirror, while also being able to return to its original position, ensuring the accuracy, stability, and flexibility of the mirror.

[0071] In some embodiments, as shown in Figure 4 , the mirror surface 140 is elliptical, and the extension direction of the flexible beam 120 is parallel to one of the symmetry axes of the elliptical mirror surface 140, such as the major axis or the minor axis of the ellipse.

[0072] In one embodiment, the mirror surface 140 is elliptical with a major axis diameter of 10 mm and a minor axis diameter of 9 mm, and a gold film of a certain thickness is deposited on the surface to achieve optical reflection. The coil frame 130 is provided with a limiting groove for limiting the position of the coil assembly 200, and the coil assembly 200 is fixed in the limiting groove. For example, when the flexible beam 120 rotates by 0.17 degrees, the required static torque T is about 5 μN m.

[0073] In one embodiment, the coil in the coil assembly 200 is a fixed shape hollow coil wound by a conventional stripping process from an enameled wire, and the coil has multiple layers, each layer containing multiple turns of the coil. In a specific implementation, the coil is adhered to the coil frame 130 by organic glue.

[0074] In some embodiments, as shown in Figures 5-7 the first end surface 3111 and the second end surface 3121 are both arc surfaces; the first end surface 3111 and the second end surface 3121 are arranged along the axial direction of the arc surfaces, the radius of the first end surface 3111 is smaller than the radius of the second end surface 3121, and the axial dimension of the first end surface 3111 is greater than the axial dimension of the second end surface 3121;

[0075] and / or, the third end surface 3311 and the fourth end surface 3321 are both arc surfaces; the third end surface 3311 and the fourth end surface 3321 are arranged along the axial direction of the arc surfaces, the radius of the third end surface 3311 is greater than the radius of the fourth end surface 3321, and the axial dimension of the third end surface 3311 is greater than the axial dimension of the fourth end surface 3321.

[0076] Because the first end surface 3111 and the third end surface 3311 have a larger area, they can carry more magnetic flux. The second end surface 3121 and the fourth end surface 3321 have a smaller area, and according to the relationship that the magnetic flux density is inversely proportional to the area of the end surface, the magnetic flux density in the air gap can be significantly improved. The design of the arc surface helps to optimize the distribution of the magnetic field, so that the magnetic lines are more concentrated in the air gap, thereby reducing the occurrence of edge effect and magnetic leakage phenomenon.

[0077] In some embodiments, as shown in Figure 6 and Figure 7 the first magnetic yoke 310 includes a first section 311 and a second section 312; the first section 311 includes the first end surface 3111, and the second section 312 includes the second end surface 3121; the second section 312 is located on the side of the first section 311 facing the second magnetic yoke 330;

[0078] the second magnetic yoke 330 includes a third section 331 and a fourth section 332; the third section 331 includes the third end surface 3311, and the fourth section 332 includes the fourth end surface 3321; the fourth section 332 is located on the side of the third section 331 facing the first magnetic yoke 310.

[0079] In an embodiment, the radial arrangement helps to form a more concentrated magnetic field distribution by placing the second segment 312 outside the first segment 311, and similarly placing the third segment 331 outside the fourth segment 332. Here, outside can be understood as the side away from the center of the arc surface. The first segment 311 includes a first end surface 3111 with a smaller radius but a larger axial dimension, and the second segment 312 includes a second end surface 3121 with a larger radius but a smaller axial dimension, and the area of the first end surface 3111 is larger than that of the second end surface 3121. The third segment 331 includes a third end surface 3311 with a larger radius and a larger axial dimension, and the fourth segment 332 includes a fourth end surface 3321 with a smaller radius and a smaller axial dimension, and the area of the third end surface 3311 is larger than that of the fourth end surface 3321. Due to the inverse relationship between magnetic flux density and end surface area, the magnetic flux density of the air gap at the second end surface 3121 and the fourth end surface 3321 with smaller area is significantly improved.

[0080] Through the above arrangement, the embodiment of the application successfully realizes the focusing effect of the magnetic field, reduces the magnetic leakage phenomenon, improves the compactness of the structure, and makes the magnetic flux density in the air gap reach 0.8 Tesla.

[0081] In some embodiments, the first magnetic yoke 310 further includes at least one first intermediate segment connected between the first segment 311 and the second segment 312; and in the axial direction of the arc surface, the thickness of the at least one first intermediate segment is smaller than the thickness of the first segment 311, and the thickness of the at least one first intermediate segment is greater than the thickness of the second segment 312.

[0082] And / or, as shown in Figure 6 The second magnetic yoke 330 further includes at least one second intermediate segment 333 connected between the third segment 331 and the fourth segment 332; and in the axial direction of the arc surface, the thickness of the at least one second intermediate segment 333 is smaller than the thickness of the third segment 331, and the thickness of the at least one second intermediate segment 333 is greater than the thickness of the fourth segment 332.

[0083] The thickness design of the intermediate segment can effectively guide the flow direction of the magnetic force line, reduce the occurrence of edge effect and magnetic leakage phenomenon, and further improve the magnetic flux density in the air gap.

[0084] In addition, this multi-segment design provides greater structural flexibility, which can adjust the thickness ratio of each segment according to actual needs, thereby realizing adaptability to different application scenarios.

[0085] By introducing at least one intermediate segment in the first magnetic yoke 310 and the second magnetic yoke 330, and reasonably designing the thickness relationship in the radial and axial directions, the embodiment of the application successfully realizes the optimization of the magnetic field distribution, reduces the magnetic leakage phenomenon, and improves the flexibility of the structure.

[0086] In some embodiments, the first intermediate segments are multiple, and the multiple first intermediate segments are arranged along the direction from the first segment 311 to the second segment 312; along the direction from the first segment 311 to the second segment 312, the thickness of the first intermediate segment close to the second segment 312 is smaller than the thickness of the first intermediate segment close to the first segment 311.

[0087] And / or, the second intermediate segments 333 are multiple, and the multiple second intermediate segments 333 are arranged along the direction from the third segment 331 to the fourth segment 332; along the direction from the third segment 331 to the fourth segment 332, the thickness of the second intermediate segment 333 close to the fourth segment 332 is smaller than the thickness of the second intermediate segment 333 close to the third segment 331.

[0088] By arranging multiple first intermediate segments along the direction from the first segment 311 to the second segment 312 while adjusting the thickness relationship, and / or arranging multiple second intermediate segments 333 along the direction from the third segment 331 to the fourth segment 332 while adjusting the thickness relationship, a smoother and more gradual magnetic field distribution can be formed at the air gap. This design can ensure that the magnetic lines more uniformly transition into the air gap, thereby improving the stability and uniformity of the magnetic field.

[0089] In some embodiments, the design of the thicker outer intermediate segments along the direction of the arc surface from the center of the arc surface to the arc surface can effectively guide the magnetic lines to gradually flow into the air gap from the outside, while the design of the thinner inner intermediate segments reduces the possibility of magnetic line leakage. Such a design further reduces the occurrence of edge effects and magnetic leakage, thereby improving the magnetic flux density in the air gap.

[0090] This multi-segment design provides a higher degree of structural refinement, and the thickness ratio of each intermediate segment can be adjusted according to actual needs, thereby achieving higher adaptability to different application scenarios.

[0091] By introducing multiple intermediate segments in the first magnetic yoke 310 and the second magnetic yoke 330 and reasonably designing their arrangement and thickness relationship, the embodiments of the present application successfully achieve gradual optimization of magnetic field distribution, reduce magnetic leakage, and improve the refinement and adaptability of the structure.

[0092] In some embodiments, the first intermediate segments are multiple, and the multiple first intermediate segments are arranged along the direction from the first segment 311 to the second segment 312; along the direction from the first segment 311 to the second segment 312, the thickness of the multiple first intermediate segments gradually decreases;

[0093] And / or, the second intermediate segments 333 are multiple, and the multiple second intermediate segments 333 are arranged along the direction from the third segment 331 to the fourth segment 332; along the direction from the third segment 331 to the fourth segment 332, the thickness of the multiple second intermediate segments 333 gradually decreases.

[0094] By designing the axial dimension of at least one intermediate section to be gradually changed, a more uniform magnetic field distribution can be formed at the air gap. This design can ensure that the magnetic lines transition more smoothly into the air gap, thereby improving the stability and uniformity of the magnetic field.

[0095] The gradually changing design can effectively guide the flow direction of the magnetic lines, avoiding the occurrence of magnetic leakage due to sudden changes in the intermediate section. Such design further reduces the occurrence of edge effects and magnetic leakage, thereby improving the magnetic flux density in the air gap.

[0096] This gradually changing design provides higher structural flexibility, allowing the size change ratio of the intermediate section to be adjusted according to actual needs, thereby achieving higher adaptability to different application scenarios.

[0097] By introducing the gradually changing design of the axial dimension of the intermediate section in the first magnetic yoke 310 and the second magnetic yoke 330, the embodiments of the present application successfully achieve the optimization of the uniformity of the magnetic field distribution, reduce the magnetic leakage phenomenon, and improve the adaptability of the structure.

[0098] In one embodiment, as shown in Figure 6 and Figure 7 , the first magnetic yoke 310 and the second magnetic yoke 330 both use a chamfered and gradually changing structure to reduce the leakage of the magnetic field outside the air gap and reduce the magnetic leakage effect. For example, the magnetic field strength in the air gap is 0.8 Tesla. By applying a current of about 7 mA to both ends of the coil, a torque of about 6 μN m can be generated to drive the mirror 140 to rotate by 0.17°.

[0099] In some embodiments, as shown in Figure 2 , the magnetic circuit module 300 is two, namely magnetic circuit module 300a and magnetic circuit module 300b, and the two magnetic circuit modules 300 are symmetrically arranged on both sides of the mirror 140. For example, in the magnetic circuit module 300a, the first end face 3111 of the first magnetic yoke 310 is connected with the S pole of the permanent magnet 320, and the third end face 3311 of the second magnetic yoke 330 is connected with the N pole of the permanent magnet 320; in the magnetic circuit module 300b, the first end face 3111 of the first magnetic yoke 310 is connected with the N pole of the permanent magnet 320, and the third end face 3311 of the second magnetic yoke 330 is connected with the S pole of the permanent magnet 320.

[0100] In a second aspect, the embodiments of the present application also provide a micro-electro-mechanical system turning mirror, as shown in Figures 8-11 , the micro-electro-mechanical system turning mirror includes a turning mirror chip 100, a coil assembly 200, and a magnetic circuit module 300. Wherein:

[0101] The magnetic circuit module 300 includes an inner shaft magnetic circuit module 301 and an outer shaft magnetic circuit module 302, the inner shaft magnetic circuit module 301 forms a first air gap, and the outer shaft magnetic circuit module 302 forms a second air gap;

[0102] The mirror turning chip 100 comprises an outer frame 110, an inner shaft flexible beam 121, an inner shaft coil frame 131, an outer shaft flexible beam 122, an outer shaft coil frame 132 and a mirror surface 140; the outer frame 110 is fixed to the magnetic circuit module 300; the inner shaft coil frame 131 and the outer shaft coil frame 132 are connected between the mirror surface 140 and the outer frame 110, and the inner shaft coil frame 131 surrounds the mirror surface 140, the outer shaft coil frame 132 surrounds the inner shaft coil frame 131, and the outer frame 110 surrounds the outer shaft coil frame 132; one end of the inner shaft flexible beam 121 is connected to the inner shaft coil frame 131, and the other end is connected to the outer shaft coil frame 132; one end of the outer shaft flexible beam 122 is connected to the outer shaft coil frame 132, and the other end is connected to the outer frame 110; the extension direction of the inner shaft flexible beam 121 intersects with the extension direction of the outer shaft flexible beam 122.

[0103] The coil assembly 200 comprises an inner shaft coil 210 and an outer shaft coil 220; the inner shaft coil 210 is fixed to the inner shaft coil frame 131 and located in the first air gap; the outer shaft coil 220 is fixed to the outer shaft coil frame 132 and located in the second air gap.

[0104] The manufacturing process of the outer shaft coil 220 and the inner shaft coil 210 has multiple choices. For example, the outer shaft coil 220 and the inner shaft coil 210 are shaped hollow coils made of enameled wire through conventional demolding process with the aid of a mold. Alternatively, the outer shaft coil 220 and the inner shaft coil 210 are made of flexible circuit board process, and the coil made of flexible circuit board process is made of multiple layers of flexible circuit board. Alternatively, the outer shaft coil 220 and the inner shaft coil 210 are outer shaft electroplating independent coils and inner shaft electroplating independent coils made by semiconductor multi-layer electroplating process. Alternatively, the outer shaft coil 220 and the inner shaft coil 210 are outer shaft independent coils and inner shaft independent coils made by semiconductor process, which are made by the process of gluing-coated copper-etching-gluing. In the above choices, the coil assembly 200 and the MEMS mirror turning chip 100 are fixed by organic adhesive.

[0105] Alternatively, the outer shaft coil 220 is made by MEMS electroplating process on the outer shaft coil frame 132, and the inner shaft coil 210 is made by MEMS electroplating process on the inner shaft coil frame 131.

[0106] It should be noted that the lead-out path of the two ends of the inner shaft coil 210 passes through the outer shaft flexible beam 122.

[0107] The coil is a circular, square with chamfer, oval or irregular shape coil.

[0108] In some embodiments, the micro-electro-mechanical system rotating mirror can realize two-axis control of the movement of the mirror surface 140 by forming the inner shaft magnetic circuit module 301 and the outer shaft magnetic circuit module 302 to form a first air gap and a second air gap respectively, and arranging the inner shaft coil 210 and the outer shaft coil 220 in the two air gaps respectively. This design can ensure the accurate movement of the mirror surface 140 in two directions.

[0109] By dividing the magnetic circuit module 300 into the inner shaft magnetic circuit module 301 and the outer shaft magnetic circuit module 302, and reasonably designing the multi-level structure of the rotating mirror chip 100 and the layout mode of the coil assembly 200, the embodiments of the present application successfully realize two-axis control of the movement of the mirror surface 140, while ensuring the stability, flexibility and compactness of the system.

[0110] In one embodiment, as shown in Figure 8 , the rotating mirror chip 100 is composed of monocrystalline silicon. A certain thickness of gold film is deposited on the surface of the mirror surface 140 to realize the reflection of the optical mirror surface 140. The inner shaft coil frame 131 and the outer shaft coil frame 132 each include a limiting groove for limiting the position of the inner shaft coil 210 and the outer shaft coil 220 respectively. For example, when the inner shaft flexible beam 121 and the outer shaft flexible beam 122 are both rotated by 0.17°, the required static torque T is about 6 μN m and 10 μN m respectively. The inner shaft flexible beam 121 and the outer shaft flexible beam 122 are both rectangular cross-section flexible beams.

[0111] The outer frame 110 of the rotating mirror chip 100 is fixed to the second magnetic yoke 330b in the outer shaft magnetic circuit module 302. In a specific implementation, as shown in Figure 8 and Figure 12 , a plurality of positioning bosses 3021 are arranged on the upper surface of the outer shaft magnetic circuit module 302. The outer shaft magnetic circuit module 302 limits the relative position of the rotating mirror chip 100 and the outer shaft magnetic circuit module 302 through the plurality of positioning bosses 3021, and the two are fixed through organic glue.

[0112] It should be noted that Figure 8 four positioning bosses 3021 are shown in the figure, but the embodiments of the present application are not limited to four.

[0113] In some embodiments, the mirror surface 140 is circular, and the extension direction of the inner shaft flexible beam 121 and the extension direction of the outer shaft flexible beam 122 are parallel to two orthogonal symmetry axes of the mirror surface 140 respectively.

[0114] The circular mirror surface 140 design combined with the extension direction of the inner shaft flexible beam 121 and the extension direction of the outer shaft flexible beam 122 being parallel to two orthogonal symmetry axes of the mirror surface 140 respectively can realize independent control of the mirror surface 140 in two directions.

[0115] The thickness of mirror 140 is only tens to hundreds of micrometers, and its low moment of inertia enables the system to respond to external input signals more quickly, improving the overall dynamic performance.

[0116] Figure 12 This is a top view of the external shaft magnetic circuit module 302a. In one embodiment, as shown... Figure 12 As shown, the outer shaft magnetic circuit module 302a includes a first magnetic yoke 310b, a permanent magnet 320b, and a second magnetic yoke 330b. Figure 12 From the perspective of [the viewpoint], the second magnetic yoke 330b is a ring-shaped sector, i.e., a sector ring. The central angle corresponding to the sector ring of the second magnetic yoke 330b is 90°. The cross-section through the axis of the sector ring is an inverted L-shape. The top view structure of the permanent magnet 320b is also a ring-shaped sector, i.e., a sector ring, and the cross-section through the axis of the sector ring is rectangular. The central angle corresponding to the sector ring of the permanent magnet 320b is 90°. For example, the difference between the inner radius and the outer radius of the permanent magnet 320b is tm1 = 5.3 mm.

[0117] like Figure 13 As shown, the second magnetic yoke 330b is divided into several segments along the radial direction. The specific division boundaries are referenced in [reference needed]. Figure 13 The dashed line runs along the outer circumferential surface of the second magnetic yoke 330b to the inner circumferential surface, with the inner segment having a smaller thickness than the outer segment. The outermost segment, 331b, has the largest radius, and there are three intermediate segments 333b in the middle. The innermost segment, 332b, has the smallest radius. The third segment 331b has a third end face 3311b, which is connected to the first magnetic pole (such as the N pole) of the permanent magnet 320b and is adapted to the shape and size of the outer surface of the first magnetic pole. It should be noted that the upper surfaces of the third segment 331b, the fourth segment 332b, and the multiple intermediate segments 333b located between the segments are coplanar.

[0118] like Figure 12 and Figure 14 As shown, the first magnetic yoke 310b includes a first segment 311b and a second segment 312b. The radial cross-section of the first magnetic yoke 310b is arched. It should be noted that the first magnetic yoke 310b has a certain size of clearance in the height direction to provide space for the inner shaft flexible beam 121, the inner shaft coil frame 131, and the mirror 140 to perform torsional movements.

[0119] In some embodiments, there are two inner axis magnetic circuit modules 301 and two outer axis magnetic circuit modules 302. The two inner axis magnetic circuit modules 301 are disposed on both sides of the mirror surface 140 relative to the inner axis flexible beam 121; the two outer axis magnetic circuit modules 302 are disposed on both sides of the mirror surface 140 relative to the outer axis flexible beam 122.

[0120] In one embodiment, such as Figure 10 As shown, and in combination Figure 8The micro-electro-mechanical system rotating mirror includes two inner shaft magnetic circuit modules 301 and two outer shaft magnetic circuit modules 302. The two inner shaft magnetic circuit modules 301 are an inner shaft magnetic circuit module 301a and an inner shaft magnetic circuit module 301b, and the inner shaft magnetic circuit module 301a and the inner shaft magnetic circuit module 301b are arranged on both sides of the mirror surface 140 opposite the inner shaft flexible beam 121. The two outer shaft magnetic circuit modules 302 are an outer shaft magnetic circuit module 302a and an outer shaft magnetic circuit module 302b, and the outer shaft magnetic circuit module 302a and the outer shaft magnetic circuit module 302b are arranged on both sides of the mirror surface 140 opposite the outer shaft flexible beam 122.

[0121] In some embodiments, in order to reduce the influence of the inner-outer shaft coupling, the avoidance patterns of the two first magnetic yokes 310b in the two outer shaft magnetic circuit modules 302 are symmetrically distributed at a certain angle offset angle with the symmetry axis of the two outer shaft magnetic circuit modules 302.

[0122] Taking the outer shaft magnetic circuit module 302a as an example, as shown in Figure 13 , the second magnetic yoke 330b includes two end faces, which are a third end face 3311b and a fourth end face 3321b, the third end face 3311b is connected to the N pole of the permanent magnet 320b, and the fourth end face 3321b is a gap end face used to cooperate with the first magnetic yoke 310b to form a second air gap. The cross-sectional area of the magnetic force line passing through the third end face 3311b is Aoynm, and the cross-sectional area of the magnetic force line passing through the fourth end face 3321b is Aoyng. According to the Ohm's law of the magnetic circuit, Bom×Aoms=Bog×Aoyng+Bol×Aol, where: Bom is the working magnetic flux density of the permanent magnet 320b, Aoms is the equivalent end face cross-sectional area of the permanent magnet 320b, Bog is the magnetic flux density in the air gap, Bol is the leakage magnetic flux, and Aol is the equivalent area of the leakage magnetic flux. In the ideal case without leakage magnetic flux, Bom×Aoms=Bog×Aoyng, Bog=Bom×Aoms / Aoyng, and since Aoynm is set to be greater than Aoyng in the present design, Aoms is equal to Aoynm, and therefore Aoms / Aoyng is greater than 1, the magnetic field flux density Bog in the air gap is effectively improved. In order to reduce the leakage magnetic flux density, referring to Figure 13 , among the plurality of second intermediate segments 333b of the second magnetic yoke 330b, the thickness of the inner side segment is smaller than the thickness of the outer side segment along the direction from the outer circumferential surface to the inner circumferential surface of the second magnetic yoke 330b, so that the lower side position of the fourth end face 3321b gradually moves away from the S pole of the permanent magnet 320b; thereby reducing the distance between the second magnetic yoke 330b and the S pole end face of the permanent magnet 320b, improving the magnetic resistance of the leakage magnetic flux, reducing the leakage magnetic flux between the two magnetic poles, optimizing and concentrating the magnetic energy in the air gap, reducing the loss of magnetic energy in the Bol×Aol part, and strengthening the magnetic field flux density Bog in the air gap.

[0123] As shown in Figure 14As shown, the first magnetic yoke 310b includes two end faces, namely a first end face 3111b and a second end face 3121b, the first end face 3111b is connected to the S pole of the permanent magnet 320b, and the second end face 3121b is a gap end face. It should be noted that the gap end face is defined as the part of the second end face 3121b facing the fourth end face 3321b in the second magnetic yoke 330b. The second end face 3121b and the fourth end face 3321b cooperatively form a second air gap. The second air gap is a ring sector. The cross-sectional area of the magnetic force line passing through the first end face 3111b is Aoysm, and the cross-sectional area of the magnetic force line passing through the second end face 3121b is Aoysg. Aoynm is greater than Aoysg. The lower side of the second end face 3121b gradually moves away from the N pole of the permanent magnet 320b.

[0124] Similarly, as shown in Figure 9 and Figure 10 , and in combination with Figure 13 and Figure 14 , the outer shaft flexible beam 122 is provided with an outer shaft magnetic circuit module 302b on the side away from the outer shaft magnetic circuit module 302a. The outer shaft magnetic circuit module 302b forms another second air gap. In the outer shaft magnetic circuit module 302b, the first magnetic yoke 310b includes two end faces, namely a first end face 3111b and a second end face 3121b, the first end face 3111b is connected to the N pole of the permanent magnet 320b, and the second end face 3121b is a gap end face. The second magnetic yoke 330b includes two end faces, namely a third end face 3311b and a fourth end face 3321b, the third end face 3311b is connected to the S pole of the permanent magnet 320b, and the fourth end face 3321b is a gap end face. The second end face 3121b and the fourth end face 3321b cooperatively form a second air gap. The outer shaft coil 220 is symmetrically arranged on both sides of the outer shaft flexible beam 122. The part of the outer shaft coil 220 with a length of Lo1 and the corresponding part of the outer shaft coil frame 132 are arranged at one second air gap; the part of the outer shaft coil 220 with a length of Lo2 and the corresponding part of the outer shaft coil frame 132 are arranged at another second air gap.

[0125] The residual magnetism Br of the permanent magnet 320b is 1.2 Tesla, and the working magnetic flux density of the permanent magnet 320b is Bom.

[0126] Meanwhile, in the outer shaft magnetic circuit module 302a, the first magnetic yoke 310b and the second magnetic yoke 330b both use a high-saturation magnetic induction intensity iron-cobalt-vanadium soft magnetic alloy with a model number of 1J22, and the saturation magnetic induction intensity of this material is 2.4 Tesla. The magnetic flux density in the soft magnetic yoke is slightly saturated under the premise of having little effect on the air gap magnetic flux density Bog.

[0127] Through the above optimized design, considering the working magnetic flux density, leakage flux, and saturation flux of the permanent magnet 320b, the magnetic flux density of the static magnetic field in the second air gap ranges from 0.9 to 1 Tesla. Compared with the 0.5 Tesla in the prior art, this represents a significant improvement in the air gap magnetic flux density in a compact magnetic circuit module.

[0128] The distribution relationship of the end faces of the yoke air gap in the outer shaft magnetic circuit module 302 is as follows: second end face 3121b in the first outer shaft magnetic circuit module 302a - fourth end face 3321b in the first outer shaft magnetic circuit module 302a - fourth end face 3321b in the second outer shaft magnetic circuit module 302b - second end face 3121b in the second outer shaft magnetic circuit module 302b. The main magnetic fields generated in the first and second air gaps are in the same direction on both sides of the coplanar central axis of the mirror 140, thus satisfying the torque output principle of the DC motor, causing the energized coil to generate torque and drive the coil frame 130 and the connected mirror 140 to produce torsional motion. Applying a current of about 10mA to the two ends of the coil can generate 10μN. The torque is around m. Therefore, this design significantly reduces power consumption and improves drive efficiency.

[0129] Similarly, taking the inner shaft magnetic circuit module 301a as an example, such as Figure 9 As shown, the inner axis magnetic circuit module 301a includes a first magnetic yoke 310a, a permanent magnet 320a, and a second magnetic yoke 330a. The top view structure of the permanent magnet 320a is a ring-shaped sector, i.e., a sector ring. The cross section through the axis of the sector ring is rectangular, and the central angle corresponding to the sector ring of the permanent magnet 320a is 90°.

[0130] like Figure 15 As shown, combined with Figure 10 , Figure 10 The first magnetic yoke 310a on the upper middle side and Figure 15 The first magnetic yoke 310a on the left side is the same first magnetic yoke 310a, and is a component of the inner shaft magnetic circuit module 301a. This first magnetic yoke 310a is divided into several segments radially; the specific division boundaries are referenced... Figure 15 The dashed line runs along the center of the first magnetic yoke 310a to the outer circumferential surface, with the outermost segment having a thinner thickness than the innermost segment. The outermost segment, 312a, has the largest radius, while the middle segment has three first intermediate segments 313a. The innermost segment, 311a, has the smallest radius. The second segment 312a has the smallest thickness, and the first segment 311a has the largest thickness. The first segment 311a has a first end face 3111a, which connects to the second magnetic pole (e.g., the S pole) of the permanent magnet 320a and is adapted to the shape and size of the second magnetic pole. It should be noted that the upper surfaces of the first segment 311a, the second segment 312a, and the multiple first intermediate segments 313a located between the segments are coplanar.

[0131] Taking the inner shaft magnetic circuit module 301a as an example, such as Figure 15 As shown, the first magnetic yoke 310a includes two end faces, namely the first end face 3111a and the second end face 3121a. The first end face 3111a is connected to the S pole of the permanent magnet 320a, and the second end face 3121a is an air gap end face, used to cooperate with the second magnetic yoke 330a to form the first air gap. The cross-sectional area through which the magnetic field lines pass in the first end face 3111a is Aiysm, and the cross-sectional area through which the magnetic field lines pass in the second end face 3121a is Aiysg. According to Ohm's law for magnetic circuits, Bim × Aimn = Big × Aiysg + Bil × Ail, where: Bim is the working magnetic flux density of the permanent magnet 320a, Aimn is the equivalent cross-sectional area of ​​the end face of the permanent magnet 320a, Bil is the leakage magnetic flux density, and Ail is the equivalent leakage magnetic area. In an ideal, leakage-free magnetic field, Bim × Aimn = Big × Aiysg, and Big = Bim × Aimn / Aiysg. Since Aiysm is set greater than Aiysg in this design, and Aimn / Aiysg is greater than 1, the magnetic flux density Big in the air gap is effectively increased. To reduce the leakage flux density, refer to... Figure 15 In the plurality of first intermediate segments 313a of the first magnetic yoke 310a, the thickness of the outer segment is less than that of the inner segment along the direction from the center of the first magnetic yoke 310a to the outer peripheral surface. This causes the lower side of the second end face 3121a on the left to gradually move away from the N pole of the permanent magnet 320a in the inner shaft magnetic circuit module 301a. This reduces the distance between the first magnetic yoke 310a and the N end face of the permanent magnet 320a, increases the magnetic resistance of leakage magnetic field, reduces the leakage magnetic field between the two magnetic poles, optimizes and concentrates the magnetic energy in the air gap, reduces the loss of magnetic energy in the Bil×Ail part, and strengthens the magnetic flux density Big in the air gap.

[0132] like Figure 16 As shown, the second magnetic yoke 330a includes a third segment 331a and a fourth segment 332a. The third segment 331a includes a third end face 3311a, and the fourth segment 332a includes a fourth end face 3321a. The third end face 3311a is connected to the N pole of the permanent magnet 320a, and the fourth end face 3321a is an air gap end face used to cooperate with the first magnetic yoke 310a to form a first air gap. The first air gap is annular and fan-shaped. The cross-sectional area through which the magnetic field lines pass in the third end face 3311a is Aiynm, and the cross-sectional area through which the magnetic field lines pass in the fourth end face 3321a is Aiyng. Since Aiynm is greater than Aiyng, the magnetic flux density Big in the air gap is effectively increased. The lower side of the fourth end face 3321a gradually moves away from the S pole of the permanent magnet 320a.

[0133] Similarly, as Figure 9 and Figure 10 As shown, and in combination Figure 15 and Figure 16An inner axis magnetic circuit module 301b is provided on the side of the inner axis flexible beam 121 opposite to the inner axis magnetic circuit module 301a, forming another first air gap. In the inner axis magnetic circuit module 301b, the first magnetic yoke 310a includes two end faces, namely a first end face 3111a and a second end face 3121a. The first end face 3111a is connected to the N pole of the permanent magnet 320a, and the second end face 3121a is the air gap end face. The second magnetic yoke 330a includes two end faces, namely a third end face 3311a and a fourth end face 3321a. The third end face 3311a is connected to the S pole of the permanent magnet 320a, and the fourth end face 3321a is the air gap end face. The second end face 3121a and the fourth end face 3321a cooperate to form the first air gap. The inner shaft coil 210 is symmetrically arranged on both sides of the inner shaft flexible beam 121. The portion of the inner shaft coil 210 with a length of Li1 and the corresponding portion of the inner shaft coil frame 131 are arranged at one first air gap; the portion of the inner shaft coil 210 with a length of Li2 and the corresponding portion of the inner shaft coil frame 131 are arranged at another first air gap.

[0134] Through the above optimized design, considering the working magnetic flux density, leakage flux, and saturation flux of the permanent magnet 320a, the magnetic flux density of the static magnetic field in the first air gap is in the range of 0.5 to 0.6 Tesla. The distribution relationship of the air gap end faces of the inner yoke in the inner shaft magnetic circuit module 301 is as follows: second end face 3121a in the first inner shaft magnetic circuit module 301a - fourth end face 3321a in the first inner shaft magnetic circuit module 301a - fourth end face 3321a in the second inner shaft magnetic circuit module 301b - second end face 3121a in the second inner shaft magnetic circuit module 301b. The main magnetic fields generated in the first and second air gaps are in the same direction on both sides of the coplanar central axis of the mirror 140, thus satisfying the torque output principle of the DC motor, causing the energized coil to generate torque and drive the coil frame 130 and the connected mirror 140 to produce torsional motion. Approximately 15mA of current applied to the two ends of the coil can generate 6μN. The torque is around m. Therefore, this design significantly reduces power consumption and improves drive efficiency.

[0135] In some embodiments, such as Figure 8 As shown, the microelectromechanical system rotating mirror also includes a base 400; the magnetic circuit module 300 is fixed to the base 400 on the side opposite to the rotating mirror chip 100.

[0136] The base 400 provides a solid support for the magnetic circuit module 300, preventing the magnetic circuit module 300 from shifting position due to external vibration or impact. The base 400, magnetic circuit module 300, rotating mirror chip 100, and coil assembly 200 are integrated together to form a complete microelectromechanical system rotating mirror module.

[0137] In one embodiment, the lower side of the outer shaft magnetic circuit module 302 is connected to the metal base 400 by organic glue.

[0138] In a third aspect, the embodiments of the present application further provide a laser communication terminal, as shown in the figure, which comprises a signal / beacon laser source 01, a pre-acquisition unit 02, a transceiver combining unit 03, a fast tracking mirror 04, an acquisition tracking module 05, a relay optical path 06, a coarse tracking mechanism 07 and a transceiver telescope 08. The fast tracking mirror 04 adopts the MEMS mirror described above, and can realize high-precision and high-speed motion control. Compared with the traditional fast tracking mirror, the fast tracking mirror has the characteristics of miniaturization, low power consumption, easy batch production, high precision and good linearity. Figure 17

[0139] In specific implementation, two laser communication terminals are used in cooperation. In the process of building a link between the two terminals, the light emitted by the laser communication terminal of the other party reaches the local laser communication terminal, is received by the transceiver telescope 08, and the acquisition and coarse tracking of the signal are completed by the coarse tracking mechanism 07. The light reaches the fast tracking mirror 04 through the relay optical path 06, and the real-time compensation of the high-frequency and low-amplitude angle interference such as platform micro-vibration and coarse tracking residual error is realized by the high-frequency motion of the fast tracking mirror 04. After entering the acquisition tracking module 05, the miss distance is detected and calculated, and the light closed-loop tracking is performed according to the miss distance.

[0140] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.​

Claims

1. A magnetic circuit module, characterized by comprising: The first magnetic yoke, the permanent magnet and the second magnetic yoke; the first magnetic yoke comprises a first end face and a second end face, the second magnetic yoke comprises a third end face and a fourth end face; wherein, The first end face is connected with the first magnetic pole of the permanent magnet, and the third end face is connected with the second magnetic pole of the permanent magnet; the second end face and the fourth end face are opposite and used for forming an air gap; The area of the second end face is smaller than the area of the first end face; and / or the area of the fourth end face is smaller than the area of the third end face.

2. The magnetic circuit module according to claim 1, characterized in that, The first end face and the second end face are both arc faces; the first end face and the second end face are arranged along the axial direction of the arc face, the radius of the first end face is smaller than the radius of the second end face, and the axial dimension of the first end face is larger than the axial dimension of the second end face; And / or, the third end face and the fourth end face are both arc faces; the third end face and the fourth end face are arranged along the axial direction of the arc face, the radius of the third end face is larger than the radius of the fourth end face, and the axial dimension of the third end face is larger than the axial dimension of the fourth end face.

3. The magnetic circuit module of claim 2, wherein, The first magnetic yoke comprises a first segment and a second segment; the first segment comprises the first end face, and the second segment comprises the second end face; the second segment is located on the side of the first segment which is towards the second magnetic yoke; The second magnetic yoke comprises a third segment and a fourth segment; the third segment comprises the third end face, and the fourth segment comprises the fourth end face; the fourth segment is located on the side of the third segment which is towards the first magnetic yoke.

4. The magnetic circuit module of claim 3, wherein, The first magnetic yoke further comprises at least one first intermediate segment which is connected between the first segment and the second segment; and in the axial direction of the arc face, the thickness of the at least one first intermediate segment is smaller than the thickness of the first segment, and the thickness of the at least one first intermediate segment is larger than the thickness of the second segment; And / or, the second magnetic yoke further comprises at least one second intermediate segment which is connected between the third segment and the fourth segment; and in the axial direction of the arc face, the thickness of the at least one second intermediate segment is smaller than the thickness of the third segment, and the thickness of the at least one second intermediate segment is larger than the thickness of the fourth segment.

5. The magnetic circuit module of claim 4, wherein, The first intermediate segment is a plurality of, and the plurality of first intermediate segments are arranged along the direction from the first segment to the second segment; along the direction from the first segment to the second segment, the thickness of the first intermediate segment which is close to the second segment is smaller than the thickness of the first intermediate segment which is close to the first segment; And / or, the second intermediate segment is a plurality of, and the plurality of second intermediate segments are arranged along the direction from the third segment to the fourth segment; along the direction from the third segment to the fourth segment, the thickness of the second intermediate segment which is close to the fourth segment is smaller than the thickness of the second intermediate segment which is close to the third segment.

6. The magnetic circuit module of claim 4, wherein, The first intermediate segment is a plurality of, and the plurality of first intermediate segments are arranged along the direction from the first segment to the second segment; along the direction from the first segment to the second segment, the thickness of the plurality of first intermediate segments gradually decreases; And / or, the second intermediate section is a plurality of second intermediate sections arranged along a direction from the third section to the fourth section; along the direction from the third section to the fourth section, the plurality of second intermediate sections gradually decrease in thickness.

7. A microelectromechanical system turning mirror, characterized by The micro-electro-mechanical system rotating mirror further comprises: A rotating mirror chip comprising an outer frame, a flexible beam, a coil frame and a mirror surface; the outer frame is fixed to the magnetic circuit module; the coil frame is connected between the mirror surface and the outer frame, and the coil frame surrounds the mirror surface, and the outer frame surrounds the coil frame; one end of the flexible beam is connected to the coil frame, and the other end is connected to the outer frame; A coil assembly fixed to the coil frame and located in the air gap.

8. The microelectromechanical system turning mirror according to claim 7, characterized in that The magnetic circuit module is two, and the two magnetic circuit modules are symmetrically arranged on both sides of the mirror surface.

9. The microelectromechanical system turning mirror of claim 7, wherein, The micro-electro-mechanical system rotating mirror further comprises a base; the magnetic circuit module is fixed to the base.

10. A microelectromechanical system turning mirror, characterized by The micro-electro-mechanical system rotating mirror further comprises: A rotating mirror chip comprising an outer frame, an outer shaft flexible beam, an outer shaft coil frame, an inner shaft flexible beam, an inner shaft coil frame and a mirror surface; the outer frame is fixed to the magnetic circuit module; the inner shaft coil frame and the outer shaft coil frame are connected between the mirror surface and the outer frame, and the inner shaft coil frame surrounds the mirror surface, and the outer shaft coil frame surrounds the inner shaft coil frame, and the outer frame surrounds the outer shaft coil frame; one end of the inner shaft flexible beam is connected to the inner shaft coil frame, and the other end is connected to the outer shaft coil frame, and one end of the outer shaft flexible beam is connected to the outer shaft coil frame, and the other end is connected to the outer frame; the extension direction of the inner shaft flexible beam intersects with the extension direction of the outer shaft flexible beam; A coil assembly comprising an inner shaft coil and an outer shaft coil; the inner shaft coil is fixed to the inner shaft coil frame and located in the first air gap; the outer shaft coil is fixed to the outer shaft coil frame and located in the second air gap. The micro-electro-mechanical system rotating mirror further comprises a base; the magnetic circuit module is fixed to the base.

11. The microelectromechanical system turning mirror according to claim 10, characterized in that The micro-electro-mechanical system rotating mirror further comprises:

12. A laser communication terminal, characterized by A rotating mirror chip comprising an outer frame, an outer shaft flexible beam, an outer shaft coil frame, an inner shaft flexible beam, an inner shaft coil frame and a mirror surface; the outer frame is fixed to the magnetic circuit module; the inner shaft coil frame and the outer shaft coil frame are connected between the mirror surface and the outer frame, and the inner shaft coil frame surrounds the mirror surface, and the outer shaft coil frame surrounds the inner shaft coil frame, and the outer frame surrounds the outer shaft coil frame; one end of the inner shaft flexible beam is connected to the inner shaft coil frame, and the other end is connected to the outer shaft coil frame, and one end of the outer shaft flexible beam is connected to the outer shaft coil frame, and the other end is connected to the outer frame; the extension direction of the inner shaft flexible beam intersects with the extension direction of the outer shaft flexible beam; A coil assembly comprising an inner shaft coil and an outer shaft coil; the inner shaft coil is fixed to the inner shaft coil frame and located in the first air gap; the outer shaft coil is fixed to the outer shaft coil frame and located in the second air gap. The micro-electro-mechanical system rotating mirror further comprises a base; the magnetic circuit module is fixed to the base. The micro-electro-mechanical system rotating mirror further comprises: A rotating mirror chip comprising an outer frame, an outer shaft flexible beam, an outer shaft coil frame, an inner shaft flexible beam, an inner shaft coil frame and a mirror surface; the outer frame is fixed to the magnetic circuit module; the inner shaft coil frame and the outer shaft coil frame are connected between the mirror surface and the outer frame, and the inner shaft coil frame surrounds the mirror surface, and the outer shaft coil frame surrounds the inner shaft coil frame, and the outer frame surrounds the outer shaft coil frame; one end of the inner shaft flexible beam is connected to the inner shaft coil frame, and the other end is connected to the outer shaft coil frame, and one end of the outer shaft flexible beam is connected to the outer shaft coil frame, and the other end is connected to the outer frame; the extension direction of the inner shaft flexible beam intersects with the extension direction of the outer shaft flexible beam; A coil assembly comprising an inner shaft coil and an outer shaft coil; the inner shaft coil is fixed to the inner shaft coil frame and located in the first air gap; the outer shaft coil is fixed to the outer shaft coil frame and located in the second air gap.

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