Linear motor, variable slit device and exposure equipment
By designing magnet modules and back iron arranged vertically with gaps in the linear motor, the normal attraction force is balanced, solving the problem of fluctuation in the normal attraction force of traditional linear motors, and realizing high precision and high thrust density for compact high-speed motion.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-01
- Publication Date
- 2026-03-10
AI Technical Summary
Traditional single-sided linear motors with iron cores have significant normal attraction and fluctuations between the primary and secondary components, affecting mechanical characteristics. Furthermore, double-sided motors have higher space and cost, and the increased mover mass makes them unsuitable for high-speed motion.
Design a linear motor in which the magnet module and back iron are arranged vertically with the electromagnetic module and there is a gap. The gap is used to balance the normal attraction force. The gap design and Heilbeck array are used to reduce the fluctuation of the normal attraction force. Combined with the guide structure, high-speed motion is achieved.
It effectively balances the normal attraction force, reduces space requirements and costs, is suitable for compact high-speed linear motion structures, and improves motion accuracy and thrust density.
Smart Images
Figure CN223987027U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of semiconductor equipment technology, and in particular to a linear motor, a variable slit device, and an exposure device. Background Technology
[0002] The following problems typically exist in the application of traditional linear motors with iron cores:
[0003] 1. In a single-sided motor structure, the magnet and back iron are usually connected as secondary components. They generate an attractive force perpendicular to the driving direction of the motor with the iron core in the coil winding, which is the primary component. This attractive force is sometimes harmful and unnecessary. The attractive force fluctuates greatly with the stroke, which is not conducive to the overall mechanical characteristics of the drive mechanism.
[0004] 2. Although using a double-sided motor structure can avoid the above-mentioned attraction, twice the magnets or coils will take up more space and generate higher costs; when using a moving magnet design, the mass of the mover part will double, which is not suitable for high-speed, high-acceleration motion. Utility Model Content
[0005] The purpose of this invention is to provide a linear motor and exposure equipment to solve the problems of large normal attraction and large fluctuations in normal attraction between the primary and secondary components of traditional single-sided linear motors with iron cores.
[0006] To solve the above-mentioned technical problems, based on one aspect of this utility model, this utility model provides a linear motor, wherein the output direction of the linear motor is a first direction, characterized in that the linear motor comprises:
[0007] Stator, including back iron and electromagnetic module;
[0008] The mover includes a magnet module; the electromagnetic module, the magnet module, and the back iron are arranged sequentially along a second direction perpendicular to the first direction, and there are gaps between the magnet module, the back iron, and the electromagnetic module.
[0009] Optionally, the magnet module includes at least one magnet group, the magnet group including two permanent magnets with opposite magnetic field directions, the magnetic field directions of the permanent magnets being parallel to the second direction; or, the magnet module includes a Heilbeck array.
[0010] Optionally, the electromagnetic module includes an iron core and a winding, the winding being disposed on the iron core, and the iron core and the back iron being parallel along the first direction.
[0011] Optionally, the winding is wound around the iron core along the first direction.
[0012] Optionally, the distance between the iron core and the magnet module in the second direction is equal to the distance between the back iron and the magnet module in the second direction, and the thickness of the back iron in the second direction is equal to the thickness of the iron core in the second direction;
[0013] Alternatively, the distance between the iron core and the magnet module in the second direction is greater than the distance between the back iron and the magnet module in the second direction, and the thickness of the back iron in the second direction is less than the thickness of the iron core in the second direction;
[0014] Alternatively, the distance between the iron core and the magnet module in the second direction is less than the distance between the back iron and the magnet module in the second direction, and the thickness of the back iron in the second direction is greater than the thickness of the iron core in the second direction.
[0015] Optionally, the iron core has a plurality of first protrusions, and the plurality of first protrusions are arranged sequentially along the first direction. The first protrusions are arranged along the second direction and protrude toward the back iron protrusion, and the winding is wound on each of the first protrusions.
[0016] Optionally, the back iron has a plurality of second protrusions, which are arranged sequentially along the first direction and protrude along the second direction toward the iron core.
[0017] Optionally, the plurality of first protrusions and the plurality of protrusions are aligned one-to-one in the second direction.
[0018] Optionally, the linear motor includes a guide structure, the magnet module is connected to the guide structure, and can move along the first direction through the guide structure.
[0019] Based on another aspect of this utility model, this utility model also provides a variable slit device, which includes the linear motor described above.
[0020] In another aspect, the present invention also provides an exposure device, comprising: a fixed stage; a movable stage relative to the fixed stage; and a linear motor as described above, wherein the stator of the linear motor is connected to the fixed stage, and the mover of the linear motor is connected to the movable stage.
[0021] As described above, the linear motor generates a traveling wave magnetic field that varies in the first direction by passing alternating current through the electromagnetic module. This magnetic field interacts with the excitation magnetic field of the magnet module to produce an electromagnetic force in the stroke direction, thereby propelling the magnet module to move in the first direction. The iron core and back iron in the electromagnetic module generate magnetic attraction forces (i.e., normal attraction forces) on the magnet module in the second direction, and these two magnetic attraction forces are in opposite directions. By setting gaps between the magnet module and the back iron and the electromagnetic module, these gaps can be used to balance the two magnetic attraction forces. In this way, the present invention can solve the problems of large normal attraction forces and large fluctuations in normal attraction forces between the primary and secondary components of traditional single-sided iron-core linear motors. At the same time, the linear motor of the present invention inherits the characteristics of traditional single-sided iron-core motors, which require less installation space and have high thrust density, and is suitable for compact high-speed linear motion structures with high requirements for interference forces.
[0022] It should be noted that since both the exposure equipment and the variable slit device include the linear motor, they also have the technical effects brought by the linear motor, which will not be repeated here. Attached Figure Description
[0023] Those skilled in the art will understand that the accompanying drawings are provided to better understand the present invention and do not constitute any limitation on the scope of the present invention. Wherein:
[0024] Figure 1 This is a schematic diagram of the linear motor according to Embodiment 1 of this utility model;
[0025] Figure 2 This is a side view of the linear motor of Embodiment 1 of this utility model along the first direction;
[0026] Figure 3 This is a front view of the linear motor in the second direction according to Embodiment 1 of this utility model;
[0027] Figure 4 This is a schematic diagram of the linear motor according to Embodiment 2 of this utility model;
[0028] Figure 5 This is a front view of the linear motor in the second embodiment of this utility model along the second direction;
[0029] Figure 6 This is a schematic diagram of the exposure device according to Embodiment 3 of this utility model.
[0030] In the attached image:
[0031] 10-Back iron; 11-Second protrusion; 20-Electromagnetic module; 21-Iron core; 210-First protrusion; 22-Winding; 30-Magnet module; 31-Permanent magnet; 41-Guide rail; 42-Slider. Detailed Implementation
[0032] To make the objectives, advantages, and features of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to facilitate and clarify the explanation of the objectives of the embodiments of this utility model. Furthermore, the structures shown in the drawings are often part of the actual structure. In particular, different drawings may emphasize different aspects and sometimes use different scales.
[0033] As used in this invention, the singular forms “a,” “an,” and “the” include plural objects; the term “or” is generally used to include the meaning of “and / or”; the term “a number” is generally used to include the meaning of “at least one”; and the term “at least two” is generally used to include the meaning of “two or more”. Furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with “first,” “second,” or “third” may explicitly or implicitly include one or at least two of that feature. “One end” and “the other end,” as well as “proximal end” and “far end,” generally refer to two corresponding parts, including not only endpoints. The terms “installed,” “connected,” and “joined” should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two elements or the interaction between two elements. Furthermore, as used in this invention, the phrase "one element is disposed on another element" generally only indicates that there is a connection, coupling, cooperation, or transmission relationship between the two elements. This connection, coupling, cooperation, or transmission can be direct or indirect through an intermediate element, and should not be construed as indicating or implying a spatial positional relationship between the two elements. That is, one element can be located arbitrarily inside, outside, above, below, or to one side of the other element, unless otherwise explicitly stated. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0034] Example 1
[0035] See Figure 1 and Figure 2This embodiment schematically provides a linear motor. The output direction (driving direction) of the linear motor is defined as the first direction X. The linear motor includes a stator and a mover. The stator includes a back iron 10 and an electromagnetic module 20, and the mover includes a magnet module 30. As those skilled in the art will understand, based on the definitions of stator and mover in a motor, the mover is the movable part of the motor, and the stator is the fixed part of the motor. Therefore, the back iron 10 and the electromagnetic module 20 are relatively fixedly arranged. The back iron 10 and the electromagnetic module 20 can be fixedly connected by any structure, such as both being fixedly arranged on the fixed stage of the exposure equipment. The magnet module 30 can move relative to the back iron 10 and the electromagnetic module 20. Based on the output direction of the linear motor, the magnet module 30 moves along the first direction X. The magnet module 30 can, for example, be connected to the motion stage of the exposure equipment to drive the motion stage to move synchronously. Furthermore, the electromagnetic module 20, the magnet module 30, and the back iron 10 are arranged sequentially along a second direction Y, which is perpendicular to the first direction X. There are gaps between the magnet module 30 and the back iron 10 and the electromagnetic module 20. The magnetic field direction of the magnet module 30 is approximately along the Y direction. Passing alternating current into the electromagnetic module 20 generates a magnetic field, specifically a traveling wave magnetic field in the first direction X.
[0036] As described above, the linear motor generates a traveling wave magnetic field that varies in the first direction X by passing alternating current through the electromagnetic module 20. This magnetic field interacts with the excitation magnetic field of the magnet module 30 to produce an electromagnetic force in the stroke direction, thereby propelling the magnet module 30 to move in the first direction X. The structure generating the magnetic field in the electromagnetic module 20 (e.g., the iron core 21) and the back iron 10 respectively generate magnetic attraction forces (i.e., normal attraction forces) on the magnet module 30 in the second direction Y. These two magnetic attraction forces are in opposite directions. By setting gaps between the magnet module 30 and the back iron 10 and the electromagnetic module 20, these gaps can be used to balance the two magnetic attraction forces. Thus, this invention solves the problems of large normal attraction forces and large fluctuations in normal attraction forces between the primary and secondary components of traditional single-sided linear motors with an iron core 21. Furthermore, this linear motor inherits the characteristics of traditional single-sided linear motors with an iron core 21, such as small installation space requirements and high thrust density, making it suitable for compact high-speed linear motion structures with high requirements for interference resistance.
[0037] Continue reading Figure 1 In one embodiment, the magnet module 30 includes at least one magnet group, each magnet group comprising two permanent magnets 31 with opposite magnetic field directions, the magnetic field directions of the permanent magnets 31 being parallel to the second direction Y. Further, the magnet module 30 includes multiple magnet groups, and the multiple magnet groups are sequentially arranged along the first direction X. In other embodiments, the magnet module 30 includes a Heilbeck array.
[0038] Continue reading Figure 1In one embodiment, the electromagnetic module 20 includes an iron core 21 and a winding 22. The iron core 21 is made of a magnetically conductive material such as silicon steel, and the winding 22 is disposed on the iron core 21. The iron core 21 and the back iron 10 are parallel along a first direction X. For example, both the iron core 21 and the back iron 10 are plate-shaped. Thus, when alternating current is passed through the winding 22, the electromagnetic module 20 generates a traveling wave magnetic field in the first direction X.
[0039] See Figure 1 and Figure 2 Furthermore, in this embodiment, the winding 22 is specifically arranged on the iron core 21 in such a way that the winding 22 is wound around the iron core 21 along the first direction X.
[0040] In practice, the shape of the back iron 10 is not specifically limited. For example, the local shape of the back iron 10 can be adjusted to ensure that the motor balances the normal attraction force and reduces the attraction force pull during the entire stroke. For example, the thickness of the back iron 10 can be appropriately reduced at both ends along the first direction X to balance the normal attraction force.
[0041] The thickness of the back iron 10 (the thickness of the back iron 10 in the second direction Y) can be set according to the relationship between the distance (h1) between the iron core 21 and the magnet module 30 in the second direction Y and the distance (h2) between the back iron 10 and the magnet module 30 in the second direction Y. For example, the distance between the iron core 21 and the magnet module 30 in the second direction Y is equal to the distance between the back iron 10 and the magnet module 30 in the second direction Y, and the thickness of the back iron 10 in the second direction Y is equal to the thickness of the iron core 21 in the second direction Y; or, the distance between the iron core 21 and the magnet module 30 in the second direction Y is greater than the distance between the back iron 10 and the magnet module 30 in the second direction Y, and the thickness of the back iron 10 in the second direction Y is less than the thickness of the iron core 21 in the second direction Y; or, the distance between the iron core 21 and the magnet module 30 in the second direction Y is less than the distance between the back iron 10 and the magnet module 30 in the second direction Y, and the thickness of the back iron 10 in the second direction Y is greater than the thickness of the iron core 21 in the second direction Y.
[0042] See Figure 3 Furthermore, the linear motor includes a guide structure, and the magnet module 30 is connected to the guide structure and can move along the first direction X via the guide structure. In one embodiment, the guide structure includes a guide rail 41 and a slider 42. The guide rail 41 extends along the first direction X and is fixed relative to the back iron 10 and the electromagnetic module 20. For example, the guide rail 41 can be fixed on the fixed stage of the exposure equipment. The slider 42 is movable on the guide rail 41 and is connected to the magnet module 30.
[0043] This embodiment also provides an exposure apparatus, which includes a fixed stage, a movable stage that can move relative to the fixed stage, and a linear motor as described above. The stator of the linear motor is connected to the fixed stage, and the mover of the linear motor is connected to the movable stage. The number of linear motors can be one or at least two. Thus, when current is passed into the electromagnetic module 20, the stator and the mover generate an interaction force. Since the stator is restricted by the fixed stage and cannot move, the mover drives the movable stage to move under the drive of the above-mentioned force. For example, it can drive the position of the silicon wafer on the movable stage to achieve micro-adjustment, thereby improving the positional accuracy of the silicon wafer. Correspondingly, it improves the overlap between the irradiation area of the light source on the silicon wafer and the exposure area on the silicon wafer. By irradiating the photosensitive layer of the exposure area on the silicon wafer, a precisely positioned circuit diagram can be etched on the silicon wafer.
[0044]
Example 2
[0045] This embodiment only describes the differences from Embodiment 1; for the same or similar parts, please refer to the description in Embodiment 1.
[0046] See Figure 4 Unlike embodiment one, where the winding 22 is wound along the first direction X on the iron core 21, in this embodiment, the iron core 21 has multiple first protrusions 210, which are arranged sequentially along the first direction X. The first protrusions 210 protrude along the second direction Y and face the back iron 10, and the winding 22 is wound around each first protrusion 210. It can be understood that in this embodiment, the winding 22 is wound along the second direction Y on the iron core 21, thus utilizing all the generated traveling wave magnetic fields to improve driving efficiency. With this winding 22 arrangement, the magnetic attraction force in the second direction Y varies. In practice, the thickness of the back iron 10 needs to be reasonably set to ensure that the magnetic attraction force on the mover (i.e., the magnet module 30) fluctuates near zero.
[0047] See Figure 5 To further reduce the variation in magnetic attraction force perpendicular to the direction of motion, the back iron 10 is provided with multiple second protrusions 11, which are arranged sequentially along the first direction X and protrude towards the iron core 21 along the second direction Y. Furthermore, the multiple first protrusions 210 and the multiple protrusions are aligned one-to-one in the second direction Y. In addition, the widths of the first protrusions 210 and the second protrusions 11 in the first direction X can be set to be equal. The smaller the distance between the back iron 10 and the magnet module 30 in the second direction Y, the smaller the protrusion height of the second protrusions 11 in the second direction Y should be; the larger the distance between the back iron 10 and the magnet module 30 in the second direction Y, the larger the protrusion height of the second protrusions 11 in the second direction Y should be.
[0048]
Example 3
[0049] See Figure 6 The exposure equipment includes an illumination system IL, a mask stage RS, a workpiece stage WS, and a projection lens system PO. The illumination system IL is used to adjust the light beam B to a suitable illumination beam. The mask stage RS is used to support the mask R and move the mask R precisely to the working position. The mask R is used to adjust the light beam B to the desired pattern. The workpiece stage WS is used to support the substrate W and move the substrate W precisely to the working position. The projection lens system PO is used to project the pattern of the light beam B onto the substrate W.
[0050] The lighting system IL can include various optical elements, optomechanical components, and adjustment and control mechanisms to adjust and control the lighting beam through transmission, reflection, and blocking.
[0051] The mask stage RS is used to support and clamp the mask plate R. The clamping method can be mechanical, vacuum adsorption, etc. Depending on the needs of the exposure process, the mask stage RS can be fixed or movable. For structures that support multiple mask plates R, their pose can be controlled independently.
[0052] The mask R can adjust the beam into the desired pattern. The mask R can be transmissive, reflective, or arranged in an array.
[0053] The variable slit device VS in the exposure equipment typically includes a two-way shielding element to block the beam of the illumination system IL, so as to ensure that the range of the beam projected onto the mask R is limited to the target area of the desired pattern.
[0054] The workpiece stage WS typically holds and fixes the substrate W using a vacuum adsorption method. The workpiece stage WS is usually movable, moving to the corresponding position to complete processes such as loading / unloading the substrate W, measurement, and exposure.
[0055] The substrate W typically needs to be coated with a photosensitive material to chemically react with a light beam and distinguish between patterns that need to be retained or removed. The substrate W can be composed of silicon wafers or compound materials.
[0056] The projection lens system PO may include various optical elements, optomechanical components, and adjustment and control mechanisms for transferring a pattern on a mask R onto a substrate W. The pattern on the mask R may differ from the pattern on the substrate W, and its size is typically reduced. The optical elements can project the pattern onto the substrate W through transmission or reflection, and the medium between the optical elements can be air, water, or other light-transmitting media.
[0057] The exposure equipment can have two or more workpiece stages (WS) to simultaneously complete multiple photolithography processes; it can have multiple illumination systems (IL), mask (R), and projection lens systems (PO) to be stitched together to form a complete pattern.
[0058] The exposure equipment can have at least one of two working modes. One is the stepping mode, in which the mask R and the substrate W remain stationary during pattern projection, and the beam projects the pattern onto the substrate W in one go. The second is the scanning mode, in which the mask R and the substrate W are moved by the mask stage RS and the workpiece stage WS respectively during the pattern projection process. The pattern projected at each moment is a part of the complete pattern, and a complete scan forms a complete pattern.
[0059] In a variable slit device (VS), a linear motor is typically used to control the movement of a shielding component in two directions; for example, the shielding component could be a blade. Fluctuations in the normal attraction force of a conventional iron-core motor can affect the stress on the guide structure supporting the shielding component of the VS, leading to insufficient movement accuracy of the shielding component or jamming of the guide structure. This results in reduced adjustment accuracy of the beam projected onto the mask plate R by the VS. The variable slit device VS of this invention utilizes a linear motor, as in Embodiment 1 or Embodiment 2, to drive the shielding component. The back iron 10 and the iron core 21 are fixed to the frame of the VS. The permanent magnet 31 is connected to the frame of the VS via a mechanical guide rail or air bearing. The linear motor of this invention balances the normal attraction force, enabling precise control of the shielding component's movement and improving the adjustment accuracy of the beam projected onto the mask plate R by the VS.
[0060] In other embodiments, the linear motor provided in this application can also be used for the movement of the mask stage RS or the workpiece stage WS. In still other embodiments, the linear motor provided in this application can also be used in any other application requiring the use of a linear motor, and is not limited to exposure equipment.
[0061] Although the present invention has been disclosed above with reference to preferred embodiments, these embodiments are not intended to limit the present invention. For any person skilled in the art, many possible variations and modifications can be made to the technical solutions of the present invention based on the disclosed technical content, or equivalent embodiments can be modified accordingly, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, shall still fall within the protection scope of the present invention.
Claims
1. A linear motor, wherein the output direction of the linear motor is a first direction, characterized in that, The linear motor comprises: a stator comprising a back iron and an electromagnetic module; a mover comprising a magnet module; the electromagnetic module, the magnet module and the back iron are arranged in sequence along a second direction perpendicular to the first direction, and the magnet module and the back iron are both spaced apart from the electromagnetic module.
2. The linear motor of claim 1, wherein The magnet module comprises at least one magnet group, the magnet group comprises two permanent magnets with opposite magnetic field directions, and the magnetic field directions of the permanent magnets are parallel to the second direction; or the magnet module comprises a Halbach array.
3. The linear motor of claim 1, wherein The electromagnetic module comprises an iron core and a winding, the winding is arranged on the iron core, and the iron core and the back iron are parallel along the first direction.
4. The linear motor of claim 3, wherein The winding is wound on the iron core along the first direction.
5. The linear motor of claim 4, wherein, The spacing between the iron core and the magnet module in the second direction is equal to the spacing between the back iron and the magnet module in the second direction, and the thickness of the back iron in the second direction is equal to the thickness of the iron core in the second direction; Or, the spacing between the iron core and the magnet module in the second direction is greater than the spacing between the back iron and the magnet module in the second direction, and the thickness of the back iron in the second direction is less than the thickness of the iron core in the second direction; Or, the spacing between the iron core and the magnet module in the second direction is less than the spacing between the back iron and the magnet module in the second direction, and the thickness of the back iron in the second direction is greater than the thickness of the iron core in the second direction.
6. The linear motor of claim 3, wherein The iron core has a plurality of first protruding portions, and the plurality of first protruding portions are arranged in sequence along the first direction, the first protruding portion protrudes along the second direction and towards the back iron, and the winding is arranged on each first protruding portion.
7. The linear motor of claim 6, wherein The back iron has a plurality of second protruding portions, and the plurality of second protruding portions are arranged in sequence along the first direction, and the second protruding portion protrudes along the second direction and towards the iron core.
8. The linear motor of claim 7, wherein The plurality of first protruding portions and the plurality of protruding portions are aligned one by one in the second direction.
9. A variable slit device, characterized by, The linear motor comprises:
10. An exposure apparatus characterized by comprising: a stator comprising a back iron and an electromagnetic module; a mover comprising a magnet module; the electromagnetic module, the magnet module and the back iron are arranged in sequence along a second direction perpendicular to the first direction, and the magnet module and the back iron are both spaced apart from the electromagnetic module. The magnet module comprises at least one magnet group, the magnet group comprises two permanent magnets with opposite magnetic field directions, and the magnetic field directions of the permanent magnets are parallel to the second direction; or the magnet module comprises a Halbach array. The electromagnetic module comprises an iron core and a winding, the winding is arranged on the iron core, and the iron core and the back iron are parallel along the first direction. The winding is wound on the iron core along the first direction. The spacing between the iron core and the magnet module in the second direction is equal to the spacing between the back iron and the magnet module in the second direction, and the thickness of the back iron in the second direction is equal to the thickness of the iron core in the second direction; Or, the spacing between the iron core and the magnet module in the second direction is greater than the spacing between the back iron and the magnet module in the second direction, and the thickness of the back iron in the second direction is less than the thickness of the iron core in the second direction; Or, the spacing between the iron core and the magnet module in the second direction is less than the spacing between the back iron and the magnet module in the second direction, and the thickness of the back iron in the second direction is greater than the thickness of the iron core in the second direction. The iron core has a plurality of first protruding portions, and the plurality of first protruding portions are arranged in sequence along the first direction, the first protruding portion protrudes along the second direction and towards the back iron, and the winding is arranged on each first protruding portion. The back iron has a plurality of second protruding portions, and the plurality of second protruding portions are arranged in sequence along the first direction, and the second protruding portion protrudes along the second direction and towards the iron core. The plurality of first protruding portions and the plurality of protruding portions are aligned one by one in the second direction. The linear motor comprises: a stator comprising a back iron and an electromagnetic module; a mover comprising a magnet module; the electromagnetic module, the magnet module and the back iron are arranged in sequence along a second direction perpendicular to the first direction, and the magnet module and the back iron are both spaced apart from the electromagnetic module. The magnet module comprises at least one magnet group, the magnet group comprises two permanent magnets with opposite magnetic field directions, and the magnetic field directions of the permanent magnets are parallel to the second direction; or the magnet module comprises a Halbach array. The electromagnetic module comprises an iron core and a winding, the winding is arranged on the iron core, and the iron core and the back iron are parallel along the first direction. The winding is wound on the iron core along the first direction. The spacing between the iron core and the magnet module in the second direction is equal to the spacing between the back iron and the magnet module in the second direction, and the thickness of the back iron in the second direction is equal to the thickness of the iron core in the second direction; Or, the spacing between the iron core and the magnet module in the second direction is greater than the spacing between the back iron and the magnet module in the second direction, and the thickness of the back iron in the second direction is less than the thickness of the iron core in the second direction; Or, the spacing between the iron core and the magnet module in the second direction is less than the spacing between the back iron and the magnet module in the second direction, and the thickness of the back iron in the second direction is greater than the thickness of the iron core in the second direction. The iron core has a plurality of first protruding portions, and the plurality of first protruding portions are arranged in sequence along the first direction, the first protruding portion protrudes along the second direction and towards the back iron, and the winding is arranged on each first protruding portion. The back iron has a plurality of second protruding portions, and the plurality of second protruding portions are arranged in sequence along the first direction, and the second protruding portion protrudes along the second direction and towards the iron core. The plurality of first protruding portions and the plurality of protruding portions are aligned one by one in the second direction.