Magnetic circuit module, micro electro mechanical system rotating mirror and laser communication terminal

Abstract

The invention 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 magnet yoke, a permanent magnet and a second magnet yoke; the first magnet yoke comprises a first end face and a second end face, and the second magnet 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 is opposite to the fourth end face for forming an air gap; the area of the second end face is smaller than that of the first end face; and / or the area of the fourth end face is smaller than that of the third end face. According to the embodiment of the invention, the magnetic flux density of 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] This application relates to the field of microelectromechanical systems (MEMS) technology, and in particular to a magnetic circuit module, a microelectromechanical system rotating mirror, and a laser communication terminal. Background Technology

[0002] Micro-electro-mechanical systems (MEMS) microfabrication technology has greatly improved manufacturing capabilities, significantly reduced unit manufacturing costs, and shrunk device size by orders of magnitude, resulting in a tremendous leap in the ability to manufacture optical devices. MEMS-manufactured devices can reach sizes from submicron and micrometer scales to millimeter and even centimeter scales, making it a highly promising technology.

[0003] Millimeter-scale devices fabricated using MEMS micromachining technology not only inherit the advantages of large-size devices, such as large aperture and high gain, but also leverage the unique advantages of MEMS devices, such as low inertia, low power consumption, and the consistency and mass production capabilities of the manufacturing process. This significantly reduces device costs while improving performance. A typical example of a large-size optical MEMS device is a large-size MEMS optical rotating mirror.

[0004] There are four types of driving methods for optical MEMS rotating mirrors: electromagnetic, electrostatic, electrothermal, and piezoelectric. Among them, electromagnetic and piezoelectric driving methods have the largest driving force. Electromagnetically driven MEMS rotating mirrors, based on the torque generation principle of DC motors, have the advantages of high efficiency and zero net force.

[0005] Due to the extremely small size of MEMS rotating mirrors, the principle of DC motor torque generation presents insurmountable challenges when designing MEMS rotating mirrors for applications requiring lightweight design. Summary of the Invention

[0006] In the design of lightweight MEMS rotating mirrors, the lack of a proper magnetic circuit design leads to significant magnetic leakage, which severely impacts the circuit's performance and makes it difficult to generate a strong magnetic field in the air gap where the coil is located, resulting in severe magnetic leakage. This leakage significantly reduces the magnetic flux density in the air gap. Therefore, this application discloses a magnetic circuit module, a MEMS rotating mirror, and a laser communication terminal to improve the magnetic flux density in the air gap of the magnetic circuit.

[0007] To achieve the above objectives, this application provides the following technical solution: In a first aspect, embodiments of this application provide a magnetic circuit module, including a first magnetic yoke, a permanent magnet, and a second magnetic yoke; the first magnetic yoke includes a first end face and a second end face, and the second magnetic yoke includes a third end face and a fourth end face; wherein... The first end face is connected to the first magnetic pole of the permanent magnet, and the third end face is connected to the second magnetic pole of the permanent magnet; the second end face and the fourth end face are opposite to each other to form 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.

[0008] The aforementioned magnetic circuit module includes a permanent magnet, a first yoke, and a second yoke. The first end face of the first yoke is connected to the first magnetic pole of the permanent magnet, and the third end face of the second yoke is connected to the second magnetic pole of the permanent magnet. The second end face of the first yoke and the fourth end face of the second yoke are used to form an air gap. In this embodiment, the area of ​​the second end face in the first yoke is designed to be smaller than the area of ​​the first end face; and / or, the area of ​​the fourth end face in the second yoke is designed to be smaller than the area of ​​the third end face. The permanent magnet provides a stable magnetic flux, and the magnetic flux density is inversely proportional to the end face area. This embodiment can significantly increase the magnetic flux density of the air gap directly opposite the smaller second end face and / or fourth end face, thereby increasing the magnetic flux density within the air gap.

[0009] In some embodiments, both the first end face and the second end face are arc-shaped surfaces; the first end face and the second end face are arranged along the axial direction of the arc-shaped surface, 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, both the third end face and the fourth end face are arc-shaped surfaces; the third end face and the fourth end face are arranged along the axial direction of the arc-shaped surface, the radius of the third end face is greater than the radius of the fourth end face, and the axial dimension of the third end face is greater than the axial dimension of the fourth end face.

[0010] In some embodiments, the first magnetic yoke includes a first segment and a second segment; the first segment includes a first end face, and the second segment includes a second end face; along the radial direction of the arcuate surface, the second segment is located on the side of the first segment facing the second magnetic yoke; And / or, the second magnetic yoke includes a third segment and a fourth segment; the third segment includes the third end face, and the fourth segment includes the fourth end face; the fourth segment is located on the side of the third segment facing the first magnetic yoke.

[0011] In some embodiments, the first magnetic yoke further includes at least one first intermediate segment, which is connected between the first segment and the second segment; and in the axial direction of the arcuate surface, the thickness of the at least one first intermediate segment is less 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. And / or, the second magnetic yoke further includes at least one second intermediate segment connected between the third segment and the fourth segment; and in the axial direction of the arcuate surface, the thickness of the at least one second intermediate segment is less than the thickness of the third segment, and the thickness of the at least one second intermediate segment is greater than the thickness of the fourth segment.

[0012] In some embodiments, there are multiple first intermediate segments, and the multiple 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 closer to the second segment is less than the thickness of the first intermediate segment closer to the first segment; And / or, there are multiple second intermediate segments, and the multiple 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 closer to the fourth segment is less than the thickness of the second intermediate segment closer to the third segment.

[0013] In some embodiments, there are multiple first intermediate segments, and the multiple 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 multiple first intermediate segments gradually decreases; And / or, there are multiple second intermediate segments, and the multiple 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 multiple second intermediate segments gradually decreases.

[0014] Secondly, embodiments of this application also provide a microelectromechanical system (MEMS) rotating mirror, including a magnetic circuit module as described in any of the first aspects; the MEMS rotating mirror further includes: The rotating mirror chip includes 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, while 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. The coil assembly is fixed to the coil frame and located within the air gap.

[0015] In some embodiments, there are two magnetic circuit modules, and the two magnetic circuit modules are symmetrically arranged on both sides of the mirror surface.

[0016] In some embodiments, the microelectromechanical system rotating mirror further includes a base; the magnetic circuit module is fixed to the base.

[0017] Thirdly, embodiments of this application also provide a microelectromechanical system rotating mirror, including a magnetic circuit module as described in any of the first aspects; the magnetic circuit module includes an inner axis magnetic circuit module and an outer axis magnetic circuit module, the inner axis magnetic circuit module forming a first air gap, and the outer axis magnetic circuit module forming a second air gap; The microelectromechanical system rotating mirror also includes: A rotating mirror chip includes an outer frame, an outer-axis flexible beam, an outer-axis coil frame, an inner-axis flexible beam, an inner-axis coil frame, and a mirror surface. The outer frame is fixed to the magnetic circuit module. The inner-axis coil frame and the outer-axis coil frame are connected between the mirror surface and the outer frame, with the inner-axis coil frame surrounding the mirror surface, the outer-axis coil frame surrounding the inner-axis coil frame, and the outer frame surrounding the outer-axis coil frame. One end of the inner-axis flexible beam is connected to the inner-axis coil frame, and the other end is connected to the outer-axis coil frame. One end of the outer-axis flexible beam is connected to the outer-axis coil frame, and the other end is connected to the outer frame. The extension direction of the inner-axis flexible beam intersects the extension direction of the outer-axis flexible beam. A coil assembly includes an inner shaft coil and an outer shaft coil; the inner shaft coil is fixed to the inner shaft coil frame and located within the first air gap; the outer shaft coil is fixed to the outer shaft coil frame and located within the second air gap.

[0018] In some embodiments, the microelectromechanical system rotating mirror further includes a base; the magnetic circuit module is fixed to the base.

[0019] Fourthly, embodiments of this application also provide a laser communication terminal including a microelectromechanical system rotating mirror as described in any of the second aspects.

[0020] Fifthly, embodiments of this application also provide a laser communication terminal including a microelectromechanical system rotating mirror as described in any of the third aspects. Attached Figure Description

[0021] Figure 1 A schematic diagram illustrating the working principle of a DC motor; Figure 2 This application provides a schematic diagram of the structure of a microelectromechanical system rotating mirror. Figure 3 An exploded view of a microelectromechanical system rotating mirror provided in an embodiment of this application; Figure 4 This application provides a schematic diagram of the structure of a rotating mirror chip in a microelectromechanical system (MEMS) rotating mirror. Figure 5 This application provides a schematic diagram of the structure of a magnetic circuit module in a rotating mirror of a microelectromechanical system. Figure 6 This application provides a schematic diagram of the structure of the second magnetic yoke in a microelectromechanical system rotating mirror. Figure 7 This application provides a schematic diagram of the structure of the first magnetic yoke in a microelectromechanical system rotating mirror. Figure 8 This is a schematic diagram of another microelectromechanical system rotating mirror provided in an embodiment of this application; Figure 9 An exploded view of another microelectromechanical system rotating mirror provided in an embodiment of this application; Figure 10 This is a schematic diagram of the magnetic circuit module in a rotating mirror of a microelectromechanical system provided in an embodiment of this application; Figure 11 An exploded view of the rotating mirror chip and coil assembly in another microelectromechanical system rotating mirror provided in an embodiment of this application; Figure 12 This is a schematic diagram of the structure of an outer shaft magnetic circuit module in a microelectromechanical system rotating mirror provided in an embodiment of this application; Figure 13 A schematic diagram of the structure of the second magnetic yoke of the outer shaft magnetic circuit module in another microelectromechanical system rotating mirror provided in this application embodiment; Figure 14 A schematic diagram of the structure of the first magnetic yoke of the outer shaft magnetic circuit module in another microelectromechanical system rotating mirror provided in this application embodiment; Figure 15 A schematic diagram of the structure of the first magnetic yoke of the inner shaft magnetic circuit module in another microelectromechanical system rotating mirror provided in this application embodiment; Figure 16 A schematic diagram of the structure of the second magnetic yoke of the inner shaft magnetic circuit module in another microelectromechanical system rotating mirror provided in this application embodiment; Figure 17 This is a schematic diagram of the structure of a laser communication terminal provided in an embodiment of this application; 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

[0022] 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.

[0023] The excitation magnetic field in the air gap can be generated by a permanent magnet. Typically, one or both ends of the permanent magnet can be externally connected to a yoke to form a closed magnetic circuit, thereby reducing magnetic reluctance and improving efficiency. In a magnetic circuit containing a permanent magnet and a yoke, the yoke connected to the N pole of the permanent magnet is designated as the N-pole yoke. One end of the N-pole yoke is connected to the N pole of the permanent magnet, and the other end is the N-pole air gap end face. The yoke connected to the S pole of the permanent magnet is designated as the S-pole yoke. One end of the S-pole yoke is connected to the S pole of the permanent magnet, and the other end is the S-pole air gap end face. The length of the air gap is the distance between the N-pole air gap end face and the S-pole air gap end face.

[0024] Utilizing the torque generation principle of a DC motor, an excitation magnetic circuit can be constructed in a microelectromechanical system (MEMS) rotating mirror to drive a coil and generate torque, thereby causing the mirror connected to the coil to rotate. A MEMS rotating mirror where the mirror rotates around one axis is called a one-dimensional MEMS rotating mirror, while one where the mirror rotates around two orthogonal axes is called a two-dimensional MEMS rotating mirror.

[0025] Due to the extremely small size of MEMS rotating mirrors and the need for lightweight design in some applications, there are several insurmountable challenges in applying the principle of DC motor torque generation to the design of MEMS rotating mirrors.

[0026] The first challenge lies in the magnetic leakage problem inherent in the magnetic circuit when applying this principle to the design of MEMS rotating mirrors. MEMS rotating mirrors are extremely compact, ranging in size from millimeters to centimeters. When a magnetic circuit is formed by a yoke and a permanent magnet, magnetic field lines pass through the air gap, resulting in an edge magnetic field. This edge magnetic field is also known as a leakage magnetic field. Magnetic leakage typically occurs at the closest point between the permanent magnet pole and the opposite-polarity air gap end face. For example, in a magnetic circuit containing a permanent magnet, an N-pole yoke, and an S-pole yoke, if the distance between the closest point between the N-pole and S-pole air gap end faces is close to the length of the air gap, a severe magnetic leakage problem will occur. After the magnetic leakage problem occurs, the magnetic flux density Bg in the air gap will decrease significantly. Magnetic circuits lacking proper design solutions exhibit a large amount of leakage magnetic field, significantly impacting the circuit's performance and making it difficult to generate a strong magnetic field at the air gap where the coil is located, thus leading to a severe magnetic leakage problem, or magnetic circuit leakage problem.

[0027] The second challenge lies in applying the DC motor principle to MEMS rotating mirrors. In the compact magnetic circuit design of MEMS rotating mirrors, there is a contradiction between weight reduction and increased magnetic reluctance / saturation. Using a thicker yoke can reduce magnetic reluctance, but it increases size and weight; using a thinner yoke reduces the magnetic circuit space and weight, but introduces magnetic circuit saturation and increased magnetic reluctance, leading to decreased magnetic circuit performance. The total magnetic flux provided by the permanent magnet is Φ. The magnetic flux cross-sectional area of ​​the yoke is Ay, the depth is ly, and the thickness is wy, where Ay = ly × wy. The cross-sectional area of ​​the permanent magnet is Am, the depth of the permanent magnet cross-section is lm, and the thickness is wm, where Am = lm × wm. The magnetic flux density within the yoke is By = Φ / Ay. The saturation magnetic flux density of a soft magnetic yoke made of silicon steel sheet is approximately 2Tesla. The working magnetic flux density of the permanent magnet is Bm = Φ / Am. A typical remanence of a permanent magnet made of neodymium iron boron (NdFeB) is around 1.2 Tesla, and a typical operating magnetic flux density (Bm) is around 0.8 Tesla. The magnetic flux density (Φ) provided by the permanent magnet is constant; therefore, By × Ay = Bm × Am. When ly = 1m, By × wy = Bm × wm. If the yoke thickness wy = 0.5mm, wm = 1mm, and Bm = 1.2 Tesla, according to the formula above, By is greater than 2 Tesla. A By greater than 2 Tesla will lead to yoke saturation. When the yoke is saturated, the magnetic reluctance will increase significantly, resulting in a magnetic voltage drop, which in turn significantly affects the magnetic circuit performance, causing a substantial decrease in the magnetic flux density (Bg) in the air gap.

[0028] Due to the aforementioned factors, the magnetic flux density Bg in the air gap is typically less than 0.5 Tesla. Increasing the magnetic field strength of the coil becomes a key challenge in enhancing the driving capability of electromagnetic MEMS drives within a limited size.

[0029] To address the aforementioned issues, this application provides a microelectromechanical system rotating mirror that enhances the magnetic flux density in the air gap by designing a specific magnetic circuit.

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application. In the description of the embodiments of this application, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships, for example, A and / or B can represent: A alone, A and B at the same time, and B alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0031] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature, and in the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.

[0032] Firstly, such as Figures 2 to 7 As shown, this application provides a microelectromechanical system rotating mirror, including a rotating mirror chip 100, a coil assembly 200, and a magnetic circuit module 300; The magnetic circuit module 300 includes a first magnetic yoke 310, a permanent magnet 320, and a second magnetic yoke 330; the first magnetic yoke 310 includes a first end face 3111 and a second end face 3121, and the second magnetic yoke 330 includes a third end face 3311 and a fourth end face 3321; wherein... The first end face 3111 is connected to the first magnetic pole of the permanent magnet 320, and the third end face 3311 is connected to the second magnetic pole of the permanent magnet 320; the second end face 3121 and the fourth end face 3321 are opposite each other to form an air gap; 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.

[0033] In the aforementioned microelectromechanical system (MEMS) rotating mirror, the magnetic circuit module 300 includes a permanent magnet 320, a first magnetic yoke 310, and a second magnetic yoke 330. The first end face 3111 of the first magnetic yoke 310 is connected to the first magnetic pole of the permanent magnet 320, and the third end face 3311 of the second magnetic yoke 330 is connected to the second magnetic pole of the permanent magnet 320. The polarities of the first and second magnetic poles are opposite. For example, the first end face 3111 of the first magnetic yoke 310 is connected to the S pole of the permanent magnet 320, and the third end face 3311 of the second magnetic yoke 330 is connected to the 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 to form an air gap. In this embodiment, the area of ​​the second end face 3121 in the first magnetic yoke 310 is smaller than the area of ​​the first end face 3111; and / or, the area of ​​the fourth end face 3321 in the second magnetic yoke 330 is smaller than the area of ​​the third end face 3311. Since the permanent magnet 320 provides a stable magnetic flux, and the magnetic flux density is inversely proportional to the end face area, this embodiment can significantly increase the magnetic flux density of the air gap directly opposite the smaller second end face 3121 and / or fourth end face 3321, thereby increasing the magnetic flux density within the air gap.

[0034] In one embodiment, by reducing the area of ​​the second end face 3121 and the fourth end face 3321, the occurrence of the edge magnetic field, i.e., the leakage magnetic field, can be effectively reduced. This is because a smaller end face area can limit the possibility of magnetic field lines leaking from the air gap, thereby increasing the magnetic flux density Bg in the air gap. After reducing magnetic leakage, more magnetic field lines will concentrate in the air gap, thereby generating a stronger magnetic field at the air gap. This helps to improve the driving efficiency of the rotating mirror. This embodiment significantly reduces the magnetic leakage problem and enhances the magnetic field strength in the air gap by optimizing the structure of the magnetic circuit module 300, thus improving the driving efficiency of the rotating mirror. This is of great significance for the use of MEMS rotating mirrors in miniaturized and high-precision application scenarios.

[0035] In some embodiments, such as Figures 2-4 As shown, the rotating 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, while 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 is located within the air gap of the magnetic circuit.

[0036] like Figure 2 As shown, and in combination Figure 4 The rotating mirror chip 100 is fixed to the magnetic circuit module 300 by the outer frame 110. The coil frame 130 surrounds the mirror surface 140 and is connected to the flexible beam 120. This design ensures the precise movement of the mirror surface 140 under the influence of the magnetic field. The coil assembly 200 is fixed to the coil frame 130 and located in the air gap, so that the electromagnetic force generated when the current passes through the coil can directly act on the mirror surface 140, achieving precise control of the angle of the mirror surface 140.

[0037] The flexible beam 120 provides the necessary flexibility and repeatability, allowing the mirror 140 to rotate freely without friction within a certain range, which greatly improves the reliability of the rotating mirror, while also being able to return to its original position, ensuring the accuracy, stability and flexibility of the rotating mirror.

[0038] In some embodiments, such as Figure 4 As shown, the mirror 140 is elliptical, and the extension direction of the flexible beam 120 is parallel to one axis of symmetry of the elliptical mirror 140, such as the major axis or minor axis of the ellipse.

[0039] In one embodiment, the mirror 140 is elliptical with a major axis diameter of 10 mm and a minor axis diameter of 9 mm. A gold film of a certain thickness is deposited on its surface to achieve optical reflection. A limiting groove is provided on the coil frame 130 to define the position of the coil assembly 200, which is fixed within the limiting groove. For example, when the flexible beam 120 rotates 0.17 degrees, the required static torque T is approximately 5 μN. m.

[0040] In one embodiment, the coil in the coil assembly 200 is a shaped hollow coil wound from enameled wire using a conventional demolding process. The coil has several layers, with each layer containing several turns. In a specific implementation, the coil is bonded to the coil frame 130 using organic adhesive.

[0041] In some embodiments, such as Figures 5-7 As shown, both the first end face 3111 and the second end face 3121 are arc-shaped surfaces; the first end face 3111 and the second end face 3121 are arranged along the axial direction of the arc-shaped surfaces, the radius of the first end face 3111 is smaller than the radius of the second end face 3121, and the axial dimension of the first end face 3111 is larger than the axial dimension of the second end face 3121. And / or, the third end face 3311 and the fourth end face 3321 are both arc-shaped surfaces; the third end face 3311 and the fourth end face 3321 are arranged along the axial direction of the arc-shaped surfaces, the radius of the third end face 3311 is greater than the radius of the fourth end face 3321, and the axial dimension of the third end face 3311 is greater than the axial dimension of the fourth end face 3321.

[0042] Because the first end face 3111 and the third end face 3311 have larger areas, they can carry more magnetic flux. The second end face 3121 and the fourth end face 3321 have smaller areas; based on the inverse relationship between magnetic flux density and end face area, the magnetic flux density within the air gap can be significantly increased. The curved surface design helps optimize the magnetic field distribution, making the magnetic field lines more concentrated in the air gap, thereby reducing edge effects and magnetic leakage.

[0043] In some embodiments, such as Figure 6 and Figure 7 As shown, the first magnetic yoke 310 includes a first segment 311 and a second segment 312; the first segment 311 includes a first end face 3111, and the second segment 312 includes a second end face 3121; the second segment 312 is located on the side of the first segment 311 facing the second magnetic yoke 330. The second magnetic yoke 330 includes a third segment 331 and a fourth segment 332; the third segment 331 includes a third end face 3311, and the fourth segment 332 includes a fourth end face 3321; the fourth segment 332 is located on the side of the third segment 331 facing the first magnetic yoke 310.

[0044] In one embodiment, by placing the second segment 312 outside the first segment 311, and similarly placing the third segment 331 outside the fourth segment 332, this radial arrangement helps to form a more concentrated magnetic field distribution. "Outer side" can be understood as the side furthest from the center of the curved surface. The first segment 311 includes a first end face 3111 with a smaller radius but a larger axial dimension; the second segment 312 includes a second end face 3121 with a larger radius but a smaller axial dimension, with the area of ​​the first end face 3111 being larger than the area of ​​the second end face 3121. The third segment 331 includes a third end face 3311 with a larger radius and a larger axial dimension; the fourth segment 332 includes a fourth end face 3321 with a smaller radius and a smaller axial dimension, with the area of ​​the third end face 3311 being larger than the area of ​​the fourth end face 3321. Since magnetic flux density is inversely proportional to the end face area, the magnetic flux density of the air gap at the smaller-area second end face 3121 and fourth end face 3321 is significantly increased.

[0045] Through the above settings, the embodiments of this application successfully achieved the focusing effect of the magnetic field, reduced magnetic leakage, improved the compactness of the structure, and made the magnetic flux density in the air gap reach 0.8Tesla.

[0046] In some embodiments, the first magnetic yoke 310 further includes at least one first intermediate segment, which is connected between the first segment 311 and the second segment 312; and in the axial direction of the arcuate surface, the thickness of at least one first intermediate segment is less than the thickness of the first segment 311, and the thickness of at least one first intermediate segment is greater than the thickness of the second segment 312. And / or, such as Figure 6 As shown, the second magnetic yoke 330 further includes at least one second intermediate segment 333, which is connected between the third segment 331 and the fourth segment 332; and in the axial direction of the arcuate surface, the thickness of at least one second intermediate segment 333 is less than the thickness of the third segment 331, and the thickness of at least one second intermediate segment 333 is greater than the thickness of the fourth segment 332.

[0047] The thickness design of the middle section can effectively guide the flow direction of magnetic field lines, reduce edge effects and magnetic leakage, and further improve the magnetic flux density in the air gap.

[0048] In addition, this multi-segment design provides greater structural flexibility, allowing the thickness ratio of each segment to be adjusted according to actual needs, thereby achieving adaptability to different application scenarios.

[0049] By introducing at least one intermediate section in the first yoke 310 and the second yoke 330, and by rationally designing the thickness relationship between the radial and axial directions, the embodiments of this application successfully optimize the magnetic field distribution, reduce magnetic leakage, and improve the flexibility of the structure.

[0050] In some embodiments, there are multiple first intermediate segments, 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 closer to the second segment 312 is less than the thickness of the first intermediate segment closer to the first segment 311. And / or, there are multiple second intermediate segments 333, 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 closer to the fourth segment 332 is less than the thickness of the second intermediate segment 333 closer to the third segment 331.

[0051] By arranging multiple first intermediate segments along the direction from the first segment 311 to the second segment 312 while adjusting their 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 their thickness relationship, a smoother, more gradual magnetic field distribution can be formed in the air gap. This design ensures that the magnetic field lines transition more uniformly into the air gap, thereby improving the stability and uniformity of the magnetic field.

[0052] In some embodiments, the design with a thicker outer middle section pointing from the center of the arcuate surface towards the arcuate surface effectively guides magnetic field lines to gradually flow into the air gap from the outside, while the design with a thinner inner middle section reduces the possibility of magnetic field line leakage. This design further reduces edge effects and magnetic leakage, increasing the magnetic flux density within the air gap.

[0053] This multi-segment design offers a higher degree of structural refinement, allowing the thickness ratio of each intermediate segment to be adjusted according to actual needs, thereby achieving greater adaptability to different application scenarios.

[0054] By introducing multiple intermediate segments into the first magnetic yoke 310 and the second magnetic yoke 330, and by rationally designing their arrangement and thickness relationship, the embodiments of this application successfully achieved gradual optimization of the magnetic field distribution, reduced magnetic leakage, and improved the refinement and adaptability of the structure.

[0055] In some embodiments, there are multiple first intermediate segments, 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; And / or, there are multiple second intermediate segments 333, 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.

[0056] By designing the axial dimension of at least one intermediate section to be gradually varied, a more uniform magnetic field distribution can be formed in the air gap. This design ensures a smoother transition of magnetic field lines into the air gap, thereby improving the stability and uniformity of the magnetic field.

[0057] The gradually changing size design effectively guides the flow direction of magnetic field lines, preventing abrupt changes in the field lines that could lead to magnetic leakage. This design further reduces edge effects and magnetic leakage, increasing the magnetic flux density within the air gap.

[0058] This gradient design offers greater structural flexibility, allowing the proportion of changes in the size of the middle section to be adjusted according to actual needs, thereby achieving greater adaptability to different application scenarios.

[0059] By introducing a design in which the axial dimensions of the middle section gradually change in the first yoke 310 and the second yoke 330, the embodiments of this application successfully optimize the uniformity of the magnetic field distribution, reduce magnetic leakage, and improve the adaptability of the structure.

[0060] In one embodiment, such as Figure 6 and Figure 7 As shown, both the first yoke 310 and the second yoke 330 employ a chamfered gradient structure to reduce magnetic field leakage outside the air gap, thereby lowering the leakage magnetic field effect. For example, the magnetic field strength within the air gap is 0.8 Tesla. Applying a current of approximately 7 mA to the coil terminals generates a magnetic flux density of 6 μN. A torque of approximately m drives the mirror 140 to rotate 0.17°.

[0061] In some embodiments, such as Figure 2 As shown, there are two magnetic circuit modules 300, namely magnetic circuit module 300a and magnetic circuit module 300b, and the two magnetic circuit modules 300 are symmetrically arranged on both sides of mirror surface 140. For example, in magnetic circuit module 300a, the first end face 3111 of the first magnetic yoke 310 is connected to the S pole of permanent magnet 320, and the third end face 3311 of the second magnetic yoke 330 is connected to the N pole of permanent magnet 320; in magnetic circuit module 300b, the first end face 3111 of the first magnetic yoke 310 is connected to the N pole of permanent magnet 320, and the third end face 3311 of the second magnetic yoke 330 is connected to the S pole of permanent magnet 320.

[0062] Secondly, embodiments of this application also provide a microelectromechanical system rotating mirror, such as... Figures 8-11 As shown, the microelectromechanical system (MEMS) rotating mirror includes a rotating mirror chip 100, a coil assembly 200, and a magnetic circuit module 300. Wherein: 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. The rotating mirror chip 100 includes an outer frame 110, an inner axis flexible beam 121, an inner axis coil frame 131, an outer axis flexible beam 122, an outer axis coil frame 132, and a mirror surface 140. The outer frame 110 is fixed to the magnetic circuit module 300. The inner axis coil frame 131 and the outer axis coil frame 132 are connected between the mirror surface 140 and the outer frame 110, with the inner axis coil frame 131 surrounding the mirror surface 140, the outer axis coil frame 132 surrounding the inner axis coil frame 131, and the outer frame 110 surrounding the outer axis coil frame 132. One end of the inner axis flexible beam 121 is connected to the inner axis coil frame 131, and the other end is connected to the outer axis coil frame 132. One end of the outer axis flexible beam 122 is connected to the outer axis coil frame 132, and the other end is connected to the outer frame 110. The extending direction of the inner axis flexible beam 121 intersects the extending direction of the outer axis flexible beam 122. The coil assembly 200 includes 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 is located in the first air gap; the outer shaft coil 220 is fixed to the outer shaft coil frame 132 and is located in the second air gap.

[0063] The fabrication processes for the outer shaft coil 220 and the inner shaft coil 210 can be varied. For example, the outer shaft coil 220 and the inner shaft coil 210 can be shaped hollow coils wound from enameled wire using a conventional demolding process with the aid of a mold. Alternatively, the outer shaft coil 220 and the inner shaft coil 210 can be fabricated using flexible circuit board technology, where the coil is made from a multilayer flexible circuit board. Alternatively, the outer shaft coil 220 and the inner shaft coil 210 can be separate outer and inner shaft electroplated coils fabricated using a semiconductor multilayer electroplating process. Alternatively, the outer shaft coil 220 and the inner shaft coil 210 can be coils fabricated using semiconductor technology, where the coils are fabricated using a coating-copper-etching-coating-process to obtain separate outer and inner shaft coils. In the above options, the coil assembly 200 is bonded and fixed to the MEMS rotating mirror chip 100 using organic adhesive.

[0064] Alternatively, the outer shaft coil 220 is fabricated on the outer shaft coil frame 132 by MEMS electroplating process, and the inner shaft coil 210 is fabricated on the inner shaft coil frame 131 by MEMS electroplating process.

[0065] It should be noted that the lead-out paths of the two ends of the inner shaft coil 210 pass through the outer shaft flexible beam 122.

[0066] The coil can be round, square with chamfers, elliptical, or irregularly shaped.

[0067] In some embodiments, the microelectromechanical system rotating mirror achieves dual-axis control of the mirror surface 140's movement by forming a first air gap and a second air gap with an inner axis magnetic circuit module 301 and an outer axis magnetic circuit module 302, respectively, and by arranging an inner axis coil 210 and an outer axis coil 220 within the two air gaps. This design ensures precise movement of the mirror surface 140 in both directions.

[0068] By dividing the magnetic circuit module 300 into an inner axis magnetic circuit module 301 and an outer axis magnetic circuit module 302, and by rationally designing the multi-level structure of the rotating mirror chip 100 and the layout of the coil assembly 200, this embodiment of the application successfully achieves dual-axis control of the movement of the mirror 140, while ensuring the stability, flexibility and compactness of the system.

[0069] In one embodiment, such as Figure 8 As shown, the rotating mirror chip 100 is composed of single-crystal silicon. A gold film of a certain thickness is deposited on the surface of the mirror 140 to achieve optical reflection. Both the inner shaft coil frame 131 and the outer shaft coil frame 132 include limiting grooves, which are used to limit the positions of the inner shaft coil 210 and the outer shaft coil 220, respectively. For example, when both the inner shaft flexible beam 121 and the outer shaft flexible beam 122 rotate by 0.17°, the required static torque T is approximately 6 μN. m and 10μN m. Among them, the inner axis flexible beam 121 and the outer axis flexible beam 122 are both rectangular cross-section flexible beams.

[0070] The outer frame 110 of the rotating mirror chip 100 is fixed to the second magnetic yoke 330b within the outer shaft magnetic circuit module 302. In a specific implementation, as follows... Figure 8 and Figure 12 As shown, the upper surface of the outer shaft magnetic circuit module 302 is provided with multiple positioning bosses 3021. The outer shaft magnetic circuit module 302 defines the relative position of the rotating mirror chip 100 and the outer shaft magnetic circuit module 302 through the multiple positioning bosses 3021, and the two are fixed together by organic adhesive.

[0071] It should be noted that, Figure 8 The image shows four positioning bosses 3021, but the embodiments of this application are not limited to four.

[0072] In some embodiments, the mirror 140 is circular, and the extension directions of the inner axis flexible beam 121 and the outer axis flexible beam 122 are parallel to two orthogonal axes of symmetry of the mirror 140, respectively.

[0073] The circular mirror 140 design combines the extension directions of the inner axis flexible beam 121 and the outer axis flexible beam 122 with two orthogonal axes of symmetry on the mirror 140, which enables independent control of the mirror 140 in two directions.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] In one embodiment, such as Figure 10 As shown, and in combination Figure 8The microelectromechanical system (MEMS) rotating mirror includes two inner-axis magnetic circuit modules 301 and two outer-axis magnetic circuit modules 302. The two inner-axis magnetic circuit modules 301 are inner-axis magnetic circuit modules 301a and 301b, respectively, and are positioned on opposite sides of the mirror surface 140 relative to the inner-axis flexible beam 121. The two outer-axis magnetic circuit modules 302 are outer-axis magnetic circuit modules 302a and 302b, respectively, and are positioned on opposite sides of the mirror surface 140 relative to the outer-axis flexible beam 122.

[0080] In some implementations, in order to reduce the influence of inner and outer shaft coupling, the clearance patterns of the two first magnetic yokes 310b in the two outer shaft magnetic circuit modules 302 are symmetrically distributed with a certain angle of deviation from the axis of symmetry of the two outer shaft magnetic circuit modules 302.

[0081] Taking the external shaft magnetic circuit module 302a as an example, such as Figure 13 As shown, the second magnetic yoke 330b includes two end faces, namely the third end face 3311b and the 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 the air gap end face, used to cooperate with the first magnetic yoke 310b to form the second air gap. The cross-sectional area through which the magnetic field lines pass in the third end face 3311b is Aoynm, and the cross-sectional area through which the magnetic field lines pass in the fourth end face 3321b is Aoyng. According to Ohm's law for magnetic circuits, Bom × Aoms = Bog × Aoyng + Bol × Aol, where: Bom is the working magnetic flux density of the permanent magnet 320b, Aoms is the equivalent cross-sectional area of ​​the end face 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. Under ideal conditions with zero magnetic leakage, Bom × Aoms = Bog × Aoyng, and Bog = Bom × Aoms / Aoyng. Since Aoynm is set to be greater than Aoyng in this design, and Aoms equals Aoynm, Aoms / Aoyng is greater than 1, effectively increasing the magnetic flux density Bog in the air gap. To reduce the leakage flux density, refer to... Figure 13 In the multiple second intermediate sections 333b of the second magnetic yoke 330b, the thickness of the inner section is less than that of the outer section along the direction from the outer peripheral surface to the inner peripheral surface of the second magnetic yoke 330b, so that the lower 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 end face of the permanent magnet 320b, increasing the magnetic resistance of leakage magnetic field, reducing the leakage magnetic field 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 flux density Bog of the magnetic field in the air gap.

[0082] like Figure 14As shown, the first magnetic yoke 310b includes two end faces, namely the first end face 3111b and the 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 the air gap end face. It should be noted that the air gap end face is defined as the portion of the second end face 3121b directly opposite the fourth end face 3321b of the second magnetic yoke 330b. The second end face 3121b and the fourth end face 3321b cooperate to form the second air gap. The second air gap is annular and fan-shaped. The cross-sectional area through which the magnetic field lines pass in the first end face 3111b is Aoysm, and the cross-sectional area through which the magnetic field lines pass in the second end face 3121b is Aoysg. Aoynm is greater than Aoysg. The lower part of the second end face 3121b gradually moves away from the N pole of the permanent magnet 320b.

[0083] Similarly, as Figure 9 and Figure 10 As shown, and in combination Figure 13 and Figure 14 An outer-axis magnetic circuit module 302b is provided on the side of the outer-axis flexible beam 122 opposite to the outer-axis magnetic circuit module 302a, forming another second air gap. In the outer-axis 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 the air 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 the air gap end face. The second end face 3121b and the fourth end face 3321b cooperate to form the second air gap. The outer shaft coil 220 is symmetrically arranged on both sides of the outer shaft flexible beam 122. The portion of the outer shaft coil 220 with a length of Lo1 and the corresponding portion of the outer shaft coil frame 132 are arranged at one second air gap; the portion of the outer shaft coil 220 with a length of Lo2 and the corresponding portion of the outer shaft coil frame 132 are arranged at another second air gap.

[0084] The remanence Br of permanent magnet 320b is 1.2Tesla, and the working magnetic flux density of permanent magnet 320b is Bom.

[0085] Meanwhile, in the outer shaft magnetic circuit module 302a, both the first yoke 310b and the second yoke 330b use a high-saturation magnetic flux density iron-cobalt-vanadium soft magnetic alloy with grade 1J22, which has a saturation magnetic flux density of 2.4 Tesla. The magnetic flux density in the soft magnetic yoke is slightly saturated with minimal impact on the air gap magnetic flux density Bog.

[0086] 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.

[0087] 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.

[0088] 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°.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] In one embodiment, the lower side of the outer shaft magnetic circuit module 302 is connected to the metal base 400 by organic adhesive.

[0097] Thirdly, embodiments of this application also provide a laser communication terminal, such as... Figure 17 As shown, the laser communication terminal includes a signal / beacon laser source 01, an advanced aiming unit 02, a transmit / receive beam combining unit 03, a fine-tracking fast-reflecting mirror 04, a capture and tracking module 05, a relay optical path 06, a coarse-tracking mechanism 07, and a transmit / receive telescope 08. The fine-tracking fast-reflecting mirror 04 employs the aforementioned microelectromechanical system (MEMS) rotating mirror, enabling high-precision, high-speed motion control. Compared to traditional fast-reflecting mirrors, it features miniaturization, low power consumption, ease of mass production, high precision, and good linearity.

[0098] In practice, two laser communication terminals work together. During the dual-terminal link establishment process, the light emitted from the other laser communication terminal reaches the local laser communication terminal, is received by the transceiver telescope 08, and is captured and coarsely tracked by the coarse tracking mechanism 07. It then travels through the relay optical path 06 to the fine tracking fast-reflecting mirror 04, where the high-frequency movement of the mirror provides real-time compensation for external high-frequency, low-amplitude angular interference such as platform micro-vibrations and residual coarse tracking errors. After entering the capture and tracking module 05, the miss distance is detected and calculated, and optical closed-loop tracking is performed based on the miss distance.

[0099] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of this application. Therefore, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application also intends to include these modifications and variations.

Claims

1. A magnetic circuit module, characterized in that, It includes a first magnetic yoke, a permanent magnet, and a second magnetic yoke; the first magnetic yoke includes a first end face and a second end face, and the second magnetic yoke includes a third end face and a fourth end face; wherein, The first end face is connected to the first magnetic pole of the permanent magnet, and the third end face is connected to the second magnetic pole of the permanent magnet; the second end face and the fourth end face are opposite to each other to form 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, Both the first end face and the second end face are arc-shaped surfaces; the first end face and the second end face are arranged along the axial direction of the arc-shaped surfaces, 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, both the third end face and the fourth end face are arc-shaped surfaces; the third end face and the fourth end face are arranged along the axial direction of the arc-shaped surface, the radius of the third end face is greater than the radius of the fourth end face, and the axial dimension of the third end face is greater than the axial dimension of the fourth end face.

3. The magnetic circuit module according to claim 2, characterized in that, The first magnetic yoke includes a first segment and a second segment; the first segment includes a first end face, and the second segment includes a second end face; the second segment is located on the side of the first segment facing the second magnetic yoke; The second magnetic yoke includes a third segment and a fourth segment; the third segment includes the third end face, and the fourth segment includes the fourth end face; the fourth segment is located on the side of the third segment facing the first magnetic yoke.

4. The magnetic circuit module according to claim 3, characterized in that, The first magnetic yoke further includes at least one first intermediate segment, which is connected between the first segment and the second segment; and in the axial direction of the arcuate surface, the thickness of the at least one first intermediate segment is less 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. And / or, the second magnetic yoke further includes at least one second intermediate segment connected between the third segment and the fourth segment; and in the axial direction of the arcuate surface, the thickness of the at least one second intermediate segment is less than the thickness of the third segment, and the thickness of the at least one second intermediate segment is greater than the thickness of the fourth segment.

5. The magnetic circuit module according to claim 4, characterized in that, There are multiple first intermediate segments, and the multiple 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 closer to the second segment is less than the thickness of the first intermediate segment closer to the first segment; And / or, there are multiple second intermediate segments, and the multiple 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 closer to the fourth segment is less than the thickness of the second intermediate segment closer to the third segment.

6. The magnetic circuit module according to claim 4, characterized in that, There are multiple first intermediate segments, and the multiple 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 multiple first intermediate segments gradually decreases; And / or, there are multiple second intermediate segments, and the multiple 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 multiple second intermediate segments gradually decreases.

7. A microelectromechanical system rotating mirror, characterized in that, The magnetic circuit module includes any one of claims 1-6; the microelectromechanical system rotating mirror further includes: The rotating mirror chip includes 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, while 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. The coil assembly is fixed to the coil frame and located within the air gap.

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

9. The microelectromechanical system rotating mirror according to claim 7, characterized in that, The microelectromechanical system rotating mirror also includes a base; the magnetic circuit module is fixed to the base.

10. A microelectromechanical system rotating mirror, characterized in that, The magnetic circuit module includes any one of claims 1-6; the magnetic circuit module includes an inner shaft magnetic circuit module and an outer shaft magnetic circuit module, the inner shaft magnetic circuit module forming a first air gap, and the outer shaft magnetic circuit module forming a second air gap; The microelectromechanical system rotating mirror also includes: A rotating mirror chip includes an outer frame, an outer-axis flexible beam, an outer-axis coil frame, an inner-axis flexible beam, an inner-axis coil frame, and a mirror surface. The outer frame is fixed to the magnetic circuit module. The inner-axis coil frame and the outer-axis coil frame are connected between the mirror surface and the outer frame, with the inner-axis coil frame surrounding the mirror surface, the outer-axis coil frame surrounding the inner-axis coil frame, and the outer frame surrounding the outer-axis coil frame. One end of the inner-axis flexible beam is connected to the inner-axis coil frame, and the other end is connected to the outer-axis coil frame. One end of the outer-axis flexible beam is connected to the outer-axis coil frame, and the other end is connected to the outer frame. The extension direction of the inner-axis flexible beam intersects the extension direction of the outer-axis flexible beam. A coil assembly includes an inner shaft coil and an outer shaft coil; the inner shaft coil is fixed to the inner shaft coil frame and located within the first air gap; the outer shaft coil is fixed to the outer shaft coil frame and located within the second air gap.

11. The microelectromechanical system rotating mirror according to claim 10, characterized in that, The microelectromechanical system rotating mirror also includes a base; the magnetic circuit module is fixed to the base.

12. A laser communication terminal, characterized in that, Including the microelectromechanical system rotating mirror as described in any one of claims 7-11.

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