Manufacturing method of flexible magnetic film, flexible magnetic film and tactile sensor

Abstract

This application relates to a method for manufacturing a flexible magnetic film, the flexible magnetic film itself, and a tactile sensor. The manufacturing method includes: obtaining a flexible film made of a flexible substrate filled with magnetic particles; clamping the flexible film between a first clamp and a second clamp, causing the flexible film to adhere to the mating surfaces of the first and second clamps under clamping force, thereby deforming it into a magnetized film with a preset three-dimensional curved surface shape; applying a unidirectional uniform magnetic field to the magnetized film to obtain a curved magnetic film; and flattening the curved magnetic film to obtain a flexible magnetic film with a preset magnetization pattern. The preset magnetization pattern is a predefined directional distribution of the magnetization intensity vector M on the flexible magnetic film, and the shapes of the mating surfaces of the first and second clamps are determined according to the preset magnetization pattern and the magnetization direction of the unidirectional uniform magnetic field. This application can realize a predefined preset magnetization pattern on the flexible magnetic film through parametric design and digital control.

Description

Technical Field

[0001] This application relates to the field of tactile sensor technology, and in particular to a method for manufacturing a flexible magnetic film, the flexible magnetic film, and a tactile sensor. Background Technology

[0002] Magnetic tactile sensors, with their non-contact measurement principle and fully flexible integrable characteristics, play an irreplaceable role in force sensing for dexterous hand manipulation, distributed tactile reconstruction in electronic skin, and sensory-motor closed-loop control in embodied intelligent systems. Among magnetic tactile sensors, flexible magnetic tactile sensors based on magnetic elastomers are particularly well-suited to practical needs, overcoming the inherent limitations of rigid permanent magnet embedding schemes in terms of thinness, conformal surface handling, and sensing of complex deformations. The basic structure of this type of magnetic elastomer tactile sensor consists of two core functional layers: one is the magnetic elastomer (i.e., the deformation layer) which serves as the force-magnetic signal conversion medium, and the other is the magnetic sensor element (i.e., the rigid layer) which serves as the signal acquisition terminal.

[0003] To improve the sensitivity of tactile sensors, it is necessary to increase the magnetic flux density of the magnetic elastomer, thus requiring optimization of the magnetization process during manufacturing. Existing magnetization methods can be broadly categorized into two types: the first involves bonding or assembling multiple magnetic elastomers, and the second uses specialized multi-pole magnetization equipment. Both methods can produce magnetization patterns arranged in a specific structure, such as a Halbach array-like pattern, which enhances the magnetic field of the elastomer on the sensor-facing side; or, periodically alternating magnetization patterns can be obtained, providing an anisotropic magnetic field characteristic basis for achieving multi-axial force decoupling.

[0004] However, the first method has drawbacks such as hindering the miniaturization and thinning of sensors, introducing assembly errors during the bonding process, and difficulties in large-scale manufacturing. The second method, on the other hand, suffers from high iteration costs due to the inherent complexity of designing and manufacturing multi-pole magnetization equipment. Each change to the magnetization pattern (such as pole spacing, number of poles, and polarity arrangement) necessitates redesigning and manufacturing the magnetization equipment. Furthermore, the magnetization process typically requires the elastomer to be cured and molded beforehand, making it difficult to precisely program the magnetic field in arbitrary vector directions within three-dimensional space, thus limiting the ability to accurately control the orientation of magnetic domains within the elastomer.

[0005] It is evident that existing magnetic elastomers cannot achieve arbitrarily customized magnetization patterns through parametric design and digital control, nor can they adjust the output of the magnetization pattern in a programmable manner according to actual needs. This is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] The purpose of this application is to provide a method for manufacturing a flexible magnetic film, a flexible magnetic film, and a tactile sensor, so as to realize a predefined preset magnetization pattern on the flexible magnetic film through parametric design and digital control.

[0007] In a first aspect, embodiments of this application provide a method for manufacturing a flexible magnetic film, comprising:

[0008] A flexible film is obtained, the flexible film being made of a flexible substrate filled with magnetic particles;

[0009] The flexible film is clamped between the first clamp and the second clamp, so that the flexible film adheres to the mating surfaces of the first clamp and the second clamp under the action of clamping force, so as to be deformed into a magnetized film with a preset three-dimensional curved surface shape.

[0010] A unidirectional uniform magnetic field is applied to the film to be magnetized to obtain a curved magnetic film;

[0011] The curved magnetic film is flattened to obtain a flexible magnetic film with a preset magnetization pattern;

[0012] The preset magnetization pattern is a predefined directional distribution of the magnetization intensity vector M on the flexible magnetic film. The mating surface shapes of the first clamp and the second clamp are determined according to the preset magnetization pattern and the magnetization direction of the unidirectional uniform magnetic field, such that: when the unidirectional uniform magnetic field is magnetized, each magnetization direction relative to the film to be magnetized corresponds one-to-one with the direction of the magnetization intensity vector M on the flexible magnetic film.

[0013] Furthermore, the preset magnetization pattern includes at least one magnetization feature, in which the direction of all magnetization intensity vectors M continuously rotates and changes along one or more preset distribution directions; the three-dimensional surface includes at least one surface unit, each surface unit corresponding to one of the magnetization features; the magnetization direction of the unidirectional uniform magnetic field is a normal-like direction that passes through the three-dimensional surface once.

[0014] Furthermore, the curved surface unit is a hemispherical surface or a sinusoidal wave surface, the boundary contour of the magnetization feature is circular, and along any radial direction of the circle, there exists a magnetization intensity vector M whose direction continuously rotates within the magnetization feature, and the flexible substrate is an elastic material;

[0015] Alternatively, the surface unit is a toroidal surface, the boundary contour of the magnetization feature is annular, and the direction of all magnetization intensity vectors M within the magnetization feature continuously rotates and changes along the width direction of the annular shape; the flexible substrate is an elastic material.

[0016] Alternatively, the surface unit is a corrugated surface extending along a one-dimensional direction, the boundary contour of the magnetization feature is a rectangle, the width direction or length direction of the rectangle is a reference direction corresponding to the one-dimensional direction, and the direction of all magnetization intensity vectors M within the magnetization feature rotates continuously only along the reference direction.

[0017] Furthermore, the preset magnetization pattern includes multiple magnetization features, which are arranged on the flexible magnetic film in a hexagonal close-packed manner or an orthogonal grid manner.

[0018] Furthermore, the preset magnetization pattern includes at least one set of positive magnetization regions and negative magnetization regions. The positive magnetization regions and negative magnetization regions in the same set are symmetrical about a boundary line, and the directions of any two magnetization intensity vectors M that are symmetrical about the position of the boundary line are opposite. The three-dimensional surface includes at least one surface unit. Each surface unit corresponds to one set of positive magnetization regions and negative magnetization regions. Each surface unit is composed of two surface sub-units that are symmetrical about the interface. The two surface sub-units correspond to the same set of positive magnetization regions and negative magnetization regions, respectively. The magnetization direction of the unidirectional uniform magnetic field is perpendicular to the tangent direction of the interface.

[0019] Furthermore, the surface unit is one of the following: spherical cap surface, ellipsoidal cap surface, sinusoidal wave surface, conical surface, and frustum surface.

[0020] Furthermore, the three-dimensional surface includes multiple surface units arranged continuously along the straight line direction. The surface unit is a wave unit of a corrugated surface extending along the straight line direction. The positive magnetization region and the negative magnetization region are both long rectangles. The dividing line between two adjacent long rectangles is perpendicular to the straight line direction. The preset magnetization pattern is composed of multiple positive magnetization regions and negative magnetization regions arranged alternately along the straight line direction.

[0021] Furthermore, the center-to-center distance between two adjacent surface units along the arrangement direction on the three-dimensional surface is set to pitch, and the height of the surface unit is set to... The three-dimensional surface can be described by the following equation 2:

[0022] [Formula 2]

[0023] In equation 2, It is the global amplitude coefficient. With height The conversion relationship is as follows , , These represent the wavenumbers of the three-dimensional surface in the x-axis and y-axis directions, respectively, and are set to... The conversion relationship with the center pitch is as follows: ,set up The conversion relationship with the center pitch is as follows: .

[0024] Furthermore, the thickness of the flexible film is less than 1 mm; the spatial period of the preset magnetization pattern is 0.1 mm to 1 mm; and the mating surfaces of the first fixture and the second fixture are processed by fused deposition modeling technology.

[0025] Alternatively, the spatial period of the preset magnetization pattern is 1μm~100μm, and the mating surfaces of the first fixture and the second fixture are processed by photopolymerization molding technology or CNC machine tool processing technology.

[0026] Furthermore, the mating surfaces of the first fixture and the second fixture are respectively convex and concave curved surfaces, and they satisfy the complementary relationship defined by Equation 1 below.

[0027] [Formula 1] 1 2

[0028] In Equation 1, and Let represent the surface functions of the convex and concave surfaces, respectively. This indicates the height of the convex surface. 1 indicates that the convex surface and the concave surface are in the corresponding Assembly clearance at coordinate position, 2 indicates that the film to be magnetized is in the corresponding The thickness value at the coordinate position.

[0029] Secondly, embodiments of this application also provide a flexible magnetic film, comprising:

[0030] Flexible substrate; and

[0031] Magnetic particles distributed within the flexible matrix;

[0032] The flexible substrate has a preset planar shape, and the magnetic particles form a preset magnetization pattern within the flexible substrate. The magnetization pattern is a directional distribution of the magnetization intensity vector M in the plane.

[0033] The magnetization pattern includes at least one magnetization feature, wherein the direction of the magnetization intensity vector M is continuously rotated in the plane, thereby forming a magnetic field enhancement region on one side of the flexible magnetic film.

[0034] Alternatively, the magnetization pattern includes at least one set of positive magnetization regions and negative magnetization regions, wherein the positive magnetization regions and the negative magnetization regions in the same set are symmetrically distributed about a line of symmetry and such that the directions of the two symmetrical magnetization intensity vectors M are opposite.

[0035] Thirdly, embodiments of this application also provide a flexible magnetic film, which is manufactured by the manufacturing method of the flexible magnetic film described in the first aspect.

[0036] Fourthly, this application also provides a tactile sensor, including a circuit board and a flexible magnetic film. The flexible magnetic film is manufactured by the manufacturing method of the flexible magnetic film described in the first aspect. A Hall chip is provided on the circuit board, and the flexible magnetic film is stacked on the circuit board. The flexible magnetic film is fixedly disposed on the side of the Hall chip away from the circuit board.

[0037] Furthermore, the circuit board is a flexible circuit board, the Hall chip is a single-axis Hall chip, and multiple Hall chips are arranged in an array on the flexible circuit board.

[0038] Furthermore, the tactile sensor also includes an elastic layer, which is directly fixed to the side of the Hall chip facing away from the circuit board, and the flexible magnetic film is directly fixed to the side of the elastic layer facing away from the Hall chip.

[0039] Furthermore, the elastic layer includes a planar base layer directly connected to the flexible magnetic film and a plurality of deformable portions disposed on the planar base layer, with a gap between two adjacent deformable portions.

[0040] Furthermore, the cross-sectional shape of the deformed part is triangular, isosceles trapezoidal, semicircular, or semi-elliptical.

[0041] Furthermore, the elastic layer also includes a filling portion, which is disposed in the gap, and the elastic modulus of the filling portion is lower than the elastic modulus of the deformable portion.

[0042] Furthermore, the elastic layer includes a first elastic layer and a second elastic layer stacked sequentially, wherein the elastic modulus of the first elastic layer is less than that of the second elastic layer.

[0043] Compared with the prior art, the embodiments of this application have the following main advantages:

[0044] The method for manufacturing a flexible magnetic film according to embodiments of this application clamps a flexible film between a first clamp and a second clamp to form a sandwich structure of "first clamp - film to be magnetized - second clamp". The film to be magnetized has a preset three-dimensional curved surface shape, allowing it to be magnetized and then unfolded to obtain a flexible magnetic film with a preset magnetization pattern. Since the preset magnetization pattern is determined directly according to the specific needs of manufacturing the flexible magnetic film, and the mating surfaces of the first and second clamps are also determined based on the preset magnetization pattern and the magnetization direction of the unidirectional uniform magnetic field, the mating surfaces of the first and second clamps can be determined through parametric design according to actual needs. Furthermore, the determined mating surfaces can be precisely processed using digital processing technology, ensuring that the preset magnetization pattern on the final flexible magnetic film accurately meets actual requirements. Therefore, the method for manufacturing a flexible magnetic film provided by embodiments of this application can realize a predefined preset magnetization pattern on the flexible magnetic film through parametric design and digital control. Attached Figure Description

[0045] To more clearly illustrate the solutions in this application, the accompanying drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a schematic flowchart illustrating a method for manufacturing a flexible magnetic film according to an embodiment of this application.

[0047] Figure 2 A schematic diagram of the arrangement structure of the first fixture, the flexible film, and the second fixture when using the manufacturing method of the flexible magnetic film provided in an embodiment of this application;

[0048] Figure 3 When using the manufacturing method of the flexible magnetic film provided in an embodiment of this application, the surface function graphs of the first surface and the second surface are shown.

[0049] Figure 4 This is a schematic diagram of the structure in which the magnetized film is held between the first clamp and the second clamp when using the manufacturing method of the flexible magnetic film provided in the first embodiment of this application.

[0050] Figure 5 This is a schematic diagram of the structure in which the magnetized film is held between the first clamp and the second clamp when using the manufacturing method of the flexible magnetic film provided in the second embodiment of this application.

[0051] Figure 6A top view schematic diagram showing the distribution of magnetization direction on the film to be magnetized when using the manufacturing method of the flexible magnetic film provided in the first embodiment of this application;

[0052] Figure 7 Thermographic diagram of magnetization intensity on the flexible magnetic film obtained by implementing the first embodiment of this application;

[0053] Figure 8 The distribution diagrams of magnetic induction intensity and magnetic induction intensity gradient in the Z-axis direction in the plane Z=0.6mm are shown for the flexible magnetic film obtained by the conventional uniform normal magnetization method and the flexible magnetic film obtained by implementing the first embodiment and the second embodiment of this application.

[0054] Figure 9 The graphs show the variation of magnetic flux density and magnetic flux density gradient along the X-axis in the Z-axis direction of the flexible magnetic film obtained by the conventional uniform normal magnetization method and the flexible magnetic films obtained by implementing the first and second embodiments of this application, respectively.

[0055] Figure 10 A schematic diagram showing the arrangement of the first fixture, the flexible film, and the second fixture when using the manufacturing method of the flexible magnetic film provided in the third embodiment of this application;

[0056] Figure 11 A schematic diagram showing the arrangement of the first fixture, the flexible film, and the second fixture when using the manufacturing method of the flexible magnetic film provided in the fourth embodiment of this application;

[0057] Figure 12 The distribution map of magnetic induction intensity in the Z-axis direction and the thermodynamic map of magnetic induction intensity gradient in the Z-axis direction of the flexible magnetic film obtained in the third and fourth embodiments of this application are shown.

[0058] Figure 13 A schematic diagram of the arrangement structure of the first fixture and the second fixture when using the manufacturing method of the flexible magnetic film provided in the fifth embodiment of this application;

[0059] Figure 14 Thermographic diagram of magnetic induction intensity in the Z-axis direction of the flexible magnetic film obtained in the fifth embodiment of this application in the plane of Z=-0.6mm;

[0060] Figure 15 A schematic diagram of the arrangement structure of the first fixture and the second fixture when using the manufacturing method of the flexible magnetic film provided in the sixth embodiment of this application;

[0061] Figure 16 Thermographic diagram of magnetic induction intensity in the Z-axis direction of the flexible magnetic film obtained in the sixth embodiment of this application in the plane of Z=0.6mm;

[0062] Figure 17 This is a schematic diagram of the structure in which the magnetized film is held between the first clamp and the second clamp when using the manufacturing method of the flexible magnetic film provided in the seventh embodiment of this application;

[0063] Figure 18 Thermographic diagram of magnetic induction intensity in the Z-axis direction of the flexible magnetic film obtained in the seventh embodiment of this application in the plane of Z=0.6mm;

[0064] Figure 19 Thermodynamic diagram of the magnetic flux density gradient of the flexible magnetic film obtained in the seventh embodiment of this application in the Z-axis direction within a plane of Z=0.6mm;

[0065] Figure 20 This is a schematic diagram of the structure in which the magnetized film is held between the first clamp and the second clamp when using the manufacturing method of the flexible magnetic film provided in the eighth embodiment of this application.

[0066] Figure 21 A schematic diagram of the arrangement of the first fixture, the flexible film, and the second fixture when using the manufacturing method of the flexible magnetic film provided in the ninth embodiment of this application;

[0067] Figure 22 This is a schematic diagram of the structure in which the magnetized film is held between the first clamp and the second clamp when using the manufacturing method of the flexible magnetic film provided in the ninth embodiment of this application;

[0068] Figure 23 A schematic diagram of the structure of the first curved surface on the first fixture when using the manufacturing method of the flexible magnetic film provided in the ninth embodiment of this application;

[0069] Figure 24 Thermographic diagram of magnetic induction intensity in the Z-axis direction of the flexible magnetic film obtained in the ninth embodiment of this application in the plane with Z=0.6mm;

[0070] Figure 25 Thermodynamic diagram of the magnetic flux density gradient of the flexible magnetic film obtained in the ninth embodiment of this application in the Z-axis direction within a plane of Z=0.6mm;

[0071] Figure 26 A schematic diagram of the arrangement structure of the first fixture and the second fixture when using the manufacturing method of the flexible magnetic film provided in the tenth embodiment of this application;

[0072] Figure 27 Thermographic diagram of magnetic induction intensity in the Z-axis direction of the flexible magnetic film obtained in the tenth embodiment of this application in the plane of Z=0.6mm;

[0073] Figure 28 This is a cross-sectional structural diagram of a tactile sensor provided in an embodiment of this application.

[0074] Figure label:

[0075] 10. First fixture; 11. First curved surface; 20. Second fixture; 21. Second curved surface; 30. Flexible film; 31. Film to be magnetized; 32. Flexible magnetic film; 41. Planar base layer; 42. Deformation part; 50. Hall chip; 60. Circuit board. Detailed Implementation

[0076] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application, are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0077] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0078] It should be understood that although the steps in the flowcharts of the accompanying figures are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the accompanying figures may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.

[0079] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0080] Please see Figure 1-27 The first part of this application provides a method for manufacturing a flexible magnetic film, which enables the realization of a predefined preset magnetization pattern on the flexible magnetic film through parametric design and digital control. The method for manufacturing the flexible magnetic film includes:

[0081] S100. Obtain a flexible film, wherein the flexible film is made of a flexible substrate filled with magnetic particles;

[0082] S200. The flexible film is clamped between the first clamp and the second clamp, so that the flexible film adheres to the mating surfaces of the first clamp and the second clamp under the action of clamping force, so as to be deformed into a magnetized film with a preset three-dimensional curved surface shape.

[0083] S300. Apply a unidirectional uniform magnetic field to the film to be magnetized to obtain a curved magnetic film;

[0084] S400. Flatten the curved magnetic film to obtain a flexible magnetic film with a preset magnetization pattern.

[0085] The first clamp 10 and the second clamp 20 are respectively provided with a first curved surface 11 and a second curved surface 21 as mating surfaces for clamping the flexible film 30. The first curved surface 11 and the second curved surface 21 can be a concave curved surface and a convex curved surface, or a convex curved surface and a concave curved surface, respectively. When the flexible film 30 is clamped between the first clamp 10 and the second clamp 20, the flexible film 30 will conform to the first curved surface 11 and the second curved surface 21 under the action of clamping force, thereby deforming into a three-dimensional curved surface shape consistent with the shape of the first curved surface 11 and the second curved surface 21. The shape of the first curved surface 11 and the second curved surface 21 is determined according to the preset magnetization pattern and the magnetization direction of the unidirectional uniform magnetic field to ensure that the shape of the three-dimensional curved surface conforms to the preset definition, thereby ensuring that the magnetization pattern on the finally formed flexible magnetic film is the preset magnetization pattern.

[0086] The preset magnetization pattern is a predefined directional distribution of the magnetization intensity vector M on the flexible magnetic film. The magnetization intensity vector M represents the direction and magnitude of the magnetic moments in the flexible magnetic film. In this embodiment, the directional distribution of all magnetic moments in the flexible magnetic film is taken as the directional distribution of the magnetization intensity vector M, i.e., the preset magnetization pattern. More specifically, the directional distribution of the magnetization intensity vector M refers to the spatial distribution of the direction of the magnetization intensity vector M on the flexible magnetic film. Moreover, in this embodiment, considering the small thickness of the flexible magnetic film (generally less than 1 mm), it is assumed that the magnetization intensity vector along the thickness direction (i.e., the Z-axis) of the flexible magnetic film... The spatial distribution is consistent, therefore the aforementioned magnetization vector The directional distribution is actually just a magnetization vector. The direction of the magnetization intensity vector is distributed in a plane parallel to the plane of the flexible magnetic membrane. Therefore, the magnetization intensity vector... The directional distribution can also be written as Furthermore, the preset magnetization pattern is also preset according to the specific needs of manufacturing the flexible magnetic film, and the magnetization intensity vector... The directional distribution on the flexible magnetic film is arranged according to a predetermined specific pattern. For example, the predetermined magnetization pattern can be a discrete or continuous magnetization pattern similar to a Helbeck magnet array, or a multi-level textured magnetization pattern with high-frequency alternating changes.

[0087] The unidirectional uniform magnetic field has a single, definite direction. Therefore, when using the unidirectional uniform magnetic field to magnetize the film 31 to be magnetized, the magnetization pattern on the flattened flexible magnetic film can be determined according to the magnetization direction of the unidirectional uniform magnetic field and the three-dimensional curved surface shape of the film 31 to be magnetized. The unidirectional uniform magnetic field can be obtained by a single-pole uniform magnetizer (such as a pulse magnetizer), which facilitates the magnetization of the film 31 to be magnetized using a single-pole uniform magnetizer without the need for complex and costly multi-pole magnetization equipment. Furthermore, even if the preset magnetization pattern to be achieved on the flexible magnetic film changes during multiple flexible magnetic film manufacturing processes, it is only necessary to redetermine the first curved surface 11 on the first fixture 10 and the second curved surface 21 on the second fixture 20 according to the redesigned preset magnetization pattern and magnetization direction, without replacing a new set of multi-pole magnetization equipment. This can greatly reduce the manufacturing and processing costs of the magnetization equipment corresponding to changes in the preset magnetization pattern.

[0088] In step S200 above, the mating surface shapes of the first clamp 10 and the second clamp 20 are determined according to the preset magnetization pattern and the magnetization direction of the unidirectional uniform magnetic field. That is, the shapes of the first curved surface 11 of the first clamp 10 and the second curved surface 21 of the second clamp 20 are determined according to the preset magnetization pattern and the magnetization direction of the unidirectional uniform magnetic field. Furthermore, the determined shapes of the first curved surface 11 and the second curved surface 21 ensure that: when the unidirectional uniform magnetic field is magnetized, its relationship with each magnetization direction of the film to be magnetized (relative to the film 31) is equal to the magnetization intensity vector on the flexible magnetic film. The directions correspond one-to-one. Therefore, the magnetization vector on the flexible magnetic film can be made... The directional distribution (i.e., the preset magnetization pattern) is entirely determined by the magnetization direction and the shape of the film 31 to be magnetized (i.e., the three-dimensional surface).

[0089] Optionally, the shape of the first curved surface 11 is determined according to the preset magnetization pattern and the magnetization direction of the unidirectional uniform magnetic field, such that the first included angle θ1 and the second included angle θ2 are equal. Here, the first included angle θ1 refers to the angle between the magnetization intensity vector M at any position on the flexible magnetic film and the normal direction of the flexible magnetic film, and the second included angle θ2 refers to the angle between the magnetization direction at the corresponding position on the film to be magnetized 31 and the normal direction of the film to be magnetized during magnetization. The shape of the second curved surface 21 is determined after obtaining the first curved surface 11 by the complementary relationship defined in Equation 1.

[0090] It is understandable that, based on the principle of making the first included angle θ1 equal to the second included angle θ2, and the pre-determined preset magnetization pattern and the magnetization direction of the unidirectional uniform magnetic field, the shape of the first curved surface 11 that meets the requirements can be obtained. Then, based on the complementary relationship between the first curved surface 11 and the second curved surface 21 defined by Formula 1, the shape of the second curved surface 21 can be obtained.

[0091] Optionally, the first surface 11 and the second surface 21 satisfy the complementary relationship defined by Equation 1.

[0092] [Formula 1] 1 2

[0093] In Equation 1, and Let represent the surface functions of the first surface 11 and the second surface 21, respectively. This indicates the height of the convex surface or the depth of the concave surface. 1 indicates that the first surface 11 and the second surface 21 are in the corresponding Assembly clearance at coordinate position, 2 indicates that the film to be magnetized is in the corresponding The thickness value at the coordinate position.

[0094] Please see Figure 3 The complementary relationship defined by Equation 1 is explained as follows: when the first surface 11 and the second surface 21 describe their surface functions based on the same horizontal plane as a reference plane with zero height. and At that time, the openings of the convex and concave surfaces face opposite directions. If If the surface is convex, then the bottom surface of the convex surface lies on the reference plane. In the corresponding The coordinate position is directly taken as the height of the upward bulge. 1; and at this time This represents a concave surface, with its apex located on a reference plane. In the corresponding The coordinate position is the height value relative to the reference plane. 2. This height value 2 equals the depth of the concave surface. Subtract this The depth of the depression at the coordinate position. Therefore, ideally, when the convex height of the convex surface and the depression depth of the concave surface are both... hour, and The sum of the two should equal the depth of the concave surface. Or the height of the protrusion of the convex curved surface However, in this embodiment, the first curved surface 11 and the second curved surface 21 are used to clamp the flexible film 30 so that the flexible film 30 is clamped to become the magnetized film 31. Therefore, the thickness of the magnetized film 31 and the assembly gap between the first curved surface 11 and the second curved surface 21 must also be considered, thus obtaining the above formula 1.

[0095] As can be seen, Formula 1 comprehensively considers the thickness of the film to be magnetized 31 and the assembly gap between the first clamp 10 and the second clamp 20, thereby enabling the sandwich structure composed of "first clamp - film to be magnetized - second clamp" to achieve near 100% spatial replication of the curved surface morphology. This ensures that the shape of the film to be magnetized 31 is consistent with the first curved surface 11 and the second curved surface 21. That is, it can ensure that the film to be magnetized has the preset shape of the three-dimensional curved surface.

[0096] As can be seen from the limitations of Equation 1 above, the first curved surface 11 and the second curved surface 21 are "complementary." This complementarity means that when the first curved surface 11 and the second curved surface 21 clamp the flexible film 30 to form the magnetized film 31, considering the assembly gap between the first curved surface 11 and the second curved surface 21 and the thickness of the magnetized film 31 itself, the first curved surface 11 and the second curved surface 21 can fit together tightly and completely by clamping the magnetized film 31. Therefore, the flexible film 30, due to its flexible deformability, can be clamped between the first clamp 10 and the second clamp 20 to form a shape identical to the first curved surface 11 and the second curved surface 21. That is, the shape of the magnetized film 31 is consistent with the first curved surface 11 and the second curved surface 21, perfectly replicating the complex surface morphology of the first curved surface 11 and the second curved surface 21.

[0097] Before performing step S400, the first clamp 10 and the second clamp 20 can be separated to facilitate the flattening operation of the curved magnetic film, so that the curved magnetic film can be quickly flattened into the flexible magnetic film with the preset magnetization pattern.

[0098] It should be noted that the flexible substrate in this application embodiment is generally in the form of a thin film, so that the flexible thin film 30 can be obtained directly by processing methods such as punching, physical cutting, or laser cutting. The flexible substrate can also be in the form of a sheet or block. In this case, it is necessary to first use a processing technology to reduce the thickness of the flexible substrate before the flexible thin film 30 can be obtained after punching. The magnetic particles in the flexible substrate are micron-sized or nano-sized particles. In step S100, the flexible substrate being filled with magnetic particles means that the magnetic particles are uniformly dispersed or oriented in the flexible substrate, so that after it is made into the flexible thin film 30, the magnetized film 31 formed by the flexible thin film 30 can be magnetized in steps S200-S300 to make it magnetic, so that the flexible magnetic film can be finally obtained in step S400. Furthermore, the flexible film 30 obtained in step S100 needs to meet preset shape and size requirements to accurately define the shape and size of the flexible film 30, so that it can be clamped by the first clamp 10 and the second clamp 20 in the subsequent step S200 to become the magnetized film 31 with the shape of the first curved surface 11 and the second curved surface 21. For example, the preset shape of the flexible film 30 can be circular, and the preset size includes a diameter of 4.0 mm and a thickness of 0.5 mm.

[0099] For example, the specific manufacturing process of the flexible substrate may be as follows: First, a selected flexible substrate material (e.g., PDMS, Ecoflex, or polyurethane) is thoroughly mixed with magnetic particles (e.g., neodymium iron boron (NdFeB) or samarium cobalt magnet (SmCo) particles) in a predetermined ratio (e.g., 1:2). Then, the resulting mixture is vacuum degassed and further dispersed using a vacuum degassing homogenizer to remove air bubbles introduced during mixing and to make the magnetic particles more evenly distributed. Next, the treated mixture is poured into a preset mold and cured by standing at room temperature or heating to form a preset film, sheet, or block shape. A demolding operation is then performed, and after removing the mold, the flexible substrate is obtained.

[0100] The method for manufacturing a flexible magnetic film provided in this application involves clamping a flexible film 30 between a first clamp 10 and a second clamp 20 to form a sandwich structure of "first clamp - film to be magnetized - second clamp". The shape of the film to be magnetized 31 is consistent with the first curved surface 11 and the second curved surface 21, that is, the film to be magnetized 31 has a preset three-dimensional curved surface shape. This allows the film to be magnetized and then unfolded to obtain a flexible magnetic film with a preset magnetization pattern. The preset magnetization pattern is determined directly according to the specific needs of manufacturing the flexible magnetic film. The first curved surface 11 and the second curved surface 21 are also determined according to the preset magnetization pattern and the magnetization direction of the unidirectional uniform magnetic field. Therefore, the first curved surface 11 and the second curved surface 21 can be determined by parametric design according to actual needs, and then the first curved surface 11 and the second curved surface 21 can be precisely processed by digital processing technology, so that the preset magnetization pattern on the final flexible magnetic film accurately meets the actual needs. The manufacturing method provided in this application can precisely define the magnetization pattern on the flexible magnetic film according to actual needs through parametric design and digital control. This is equivalent to arbitrarily customizing the magnetization pattern on the flexible magnetic film, allowing the magnetization pattern on the flexible magnetic film to be pre-defined by precisely setting the shape of the first curved surface 11 and the second curved surface 21 and setting the magnetization direction. In other words, the manufacturing method of the flexible magnetic film provided in this application can realize a pre-defined preset magnetization pattern on the flexible magnetic film through parametric design and digital control, and the output of the magnetization pattern on the flexible magnetic film can be adjusted in a programmable manner according to actual needs.

[0101] Furthermore, the manufacturing method of the flexible magnetic film provided in this application embodiment only requires the use of a single-pole uniform magnetizer for magnetization, without the need for a dedicated multi-pole magnetizer. This can save the cost of developing and manufacturing multi-pole magnetizers and avoid the increased iterative development cost caused by redesigning the multi-pole magnetizer when the preset magnetization pattern on the flexible magnetic film changes.

[0102] In addition, the manufacturing method of the flexible magnetic film provided in this application also solves the technical problem that existing flexible magnetic films cannot improve the unilateral magnetic induction intensity of the flexible magnetic film because they cannot achieve precise programmable anisotropic magnetization, thus failing to improve the sensitivity of the tactile sensor and hindering the ultra-thinning and miniaturization of the tactile sensor.

[0103] In some embodiments, the flexible matrix is ​​a highly compliant polymer such as polydimethylsiloxane (PDMS), Ecoflex silicone, or polyurethane (PU). The magnetic particles can be neodymium iron boron (NdFeB) or barium ferrite (BaFe).12 O 19 Hard magnetic materials such as samarium cobalt magnets (SmCo) are used. The selection of hard magnetic materials for the magnetic particles allows the magnetized film 31 to generate a constant residual magnetic field after magnetization. This ensures that after the magnetized curved magnetic film is flattened into a flexible magnetic film, it can maintain a constant magnetic field in the surrounding space when not subjected to external forces or external magnetic fields. This guarantees that the flexible magnetic film will only cause a significant change in the magnetic induction intensity distribution in the surrounding space when subjected to external contact forces, which is beneficial for applying the flexible magnetic film in tactile sensors requiring high-precision contact force detection.

[0104] In some embodiments, the flexible substrate is an elastic material. When the flexible substrate is an elastic material, the first curved surface 11 of the first clamp 10 and the second curved surface 21 of the second clamp 20 can be either developable or non-developable surfaces.

[0105] It should be noted that when obtaining the flexible magnetic film using the manufacturing method of the flexible magnetic film provided in this application embodiment, during the process of clamping the flexible film 30 into the magnetized film 31, and during the process of flattening the curved magnetic film into the flexible magnetic film, these films must not be wrinkled, torn, stretched, or sheared. This is because only in this way can the first included angle θ1 be guaranteed to be equal to the second included angle θ2, and only then can each magnetization direction of the unidirectional uniform magnetic field relative to the magnetized film 31 correspond one-to-one with the direction of the magnetization intensity vector M on the flexible magnetic film. This also ensures that the magnetization direction of the unidirectional uniform magnetic field and the shape of the magnetized film 31 can accurately determine the preset magnetization pattern on the flexible magnetic film.

[0106] When the first curved surface 11 and the second curved surface 21, determined according to the preset magnetization pattern and magnetization direction, are developable surfaces, the film to be magnetized 31 (and the curved magnetic film) is also a developable surface. Therefore, during the process of the flexible film 30 being clamped by the first clamp 10 and the second clamp 20 to become the film to be magnetized 31, and during the process of the curved magnetic film being flattened to become the flexible magnetic film, no wrinkles, tears, stretching, or shearing deformation will occur. Thus, this can be achieved solely by the soft and deformable characteristics of the flexible film 30 (and the curved magnetic film) itself. The flexible substrate can be either an elastic material or a non-elastic material. When the first curved surface 11 and the second curved surface 21, determined according to the preset magnetization pattern and magnetization direction, are non-developable surfaces, the film to be magnetized 31 (and the curved magnetic film) is also a non-developable surface. During the process of the flexible film 30 being clamped by the first clamp 10 and the second clamp 20 to become the film to be magnetized 31, wrinkles, tears, stretching, or shearing deformation may occur, so it is necessary to ensure that the flexible film 30 can undergo elastic deformation. In other words, the flexible film 30 needs to rely on its stretchable and compressible properties to be completely and tightly attached to the first curved surface 11 and the second curved surface 21. Similarly, in the process of flattening the magnetized curved magnetic film into a flexible magnetic film, the curved magnetic film also needs to be able to undergo elastic deformation in order to flatten into a flexible magnetic film without wrinkling or tearing. Therefore, the flexible substrate at this time must be an elastic material.

[0107] In this embodiment, by selecting an elastic material as the flexible substrate, the first curved surface 11 and the second curved surface 21 can be either developable or non-developable, thus better adapting to the requirement that the flexible magnetic film is defined as having a variety of different preset magnetization patterns.

[0108] In other embodiments, the flexible substrate is a non-elastic material. When the flexible substrate is a non-elastic material, it may be, for example, polyester (PET) or polyimide (PI). Since the flexible film of a non-elastic material cannot undergo elastic deformation, the first curved surface 11 and the second curved surface 21 must be developable surfaces to ensure that the flexible film 30 is completely and tightly attached to the first curved surface 11 and the second curved surface 21 to be clamped into the magnetized film 31. This also ensures that the magnetized curved magnetic film can be flattened into a flexible magnetic film without wrinkling, tearing, stretching, or shearing.

[0109] For example, when the flexible substrate is a non-elastic material, the first curved surface 11 and the second curved surface 21 can be corrugated surfaces extending in a one-dimensional direction. The corrugated surface is a developable surface with a wavy, curved shape. The preset magnetization pattern of the resulting flexible magnetic film can also achieve a rotation of the magnetization direction as the wavy surface bends, so that the preset magnetization pattern on the flexible magnetic film is a magnetization pattern similar to a Hellbeck magnet array, thereby enhancing the magnetic induction intensity on one side of the flexible magnetic film, which is beneficial for the configuration of the tactile sensor.

[0110] In some embodiments, the thickness of the flexible film 30 is less than 1 mm. In a flexible magnetic film made of a flexible film 30 with a thickness within this range, the magnetization state along the thickness direction of the flexible magnetic film (i.e., the Z-axis direction) can be approximated as isotropic. Therefore, the focus can be mainly on the anisotropic magnetization direction in a two-dimensional plane (i.e., the XY plane) parallel to the flexible magnetic film. This makes it easier and more accurate to determine the shapes of the first surface 11 and the second surface 21 based on the preset magnetization pattern and the magnetization direction of the unidirectional uniform magnetic field, without considering the directional distribution of the magnetization intensity vector M on the Z-axis.

[0111] Specifically, when the thickness of the flexible film 30 is 0.1 mm to 1 mm, the manufacturing process from the flexible substrate to the flexible film 30 can be achieved based on fused deposition modeling (FDM) technology. When the thickness of the flexible film 30 is less than 0.01 mm, the flexible film 30 can be manufactured from the flexible substrate using high-precision stereolithography (SLA) technology, or the flexible substrate can be machined using a high-precision computer numerical control (CNC) machine tool to obtain the flexible film 30.

[0112] In some embodiments, the thickness of the flexible film 30 is less than 1 mm. The spatial period of the preset magnetization pattern is 0.1 mm to 1 mm, and the first curved surface 11 and the second curved surface 21 are processed by fused deposition modeling (FDM) technology.

[0113] In some embodiments, the thickness of the flexible film 3 is less than 1 mm. The spatial period of the preset magnetization pattern is 1 μm-100 μm, and the first curved surface 11 and the second curved surface 21 are processed by stereolithography (SLA) technology or computer numerical control (CNC) technology.

[0114] It should be noted that the "spatial period of the preset magnetization pattern" in this application embodiment, which is also the pole distance of the preset magnetization pattern, refers to the distance between the centers of two adjacent magnetic poles of the same polarity in the preset magnetization pattern. It can also be considered as the spatial length of a repeating unit in the preset magnetization pattern. It characterizes the speed of change of the preset magnetization pattern in spatial distribution. The smaller the period, the faster the change.

[0115] This application embodiment controls the dimensional accuracy of the first curved surface 11 and the second curved surface 21 by employing processing and manufacturing techniques with different processing precision, thereby enabling the shapes of the first curved surface 11 and the second curved surface 21 manufactured to accurately match the preset magnetization pattern, thus ensuring that the preset magnetization pattern on the finally actually manufactured flexible magnetic film meets the requirements within the dimensional accuracy range of its spatial period.

[0116] In some embodiments, the flexible film 30 is circular, and before step S100, the following steps are included: punching holes in a flexible substrate filled with magnetic particles to obtain a circular flexible film 30 and making the flexible film 30 conform to a preset diameter and a preset thickness.

[0117] Understandably, a circular flexible film 30 is advantageous for manufacturing into a circular flexible magnetic film after magnetization and flattening in subsequent steps S100-S400. Circular flexible magnetic films have a wide range of applications; therefore, in this embodiment, the default shape of the flexible film 30 is circular. Furthermore, to obtain the circular flexible film 30 simply, reliably, and at low cost, this embodiment employs a mature "punching" processing technology to process the flexible substrate filled with magnetic particles. The punching processing technology is applicable to flexible substrates in the form of films, sheets, or blocks. If the thickness of the flexible substrate meets the default thickness of the flexible film, the flexible film can be directly obtained after punching the flexible substrate. If the thickness of the flexible substrate is greater than the default thickness of the flexible film, a further thickness reduction processing technology is required after punching the flexible substrate to obtain the flexible film.

[0118] In one embodiment, the first clamp 10 has a first connecting hole at a location other than the first curved surface 11, and the second clamp 20 has a second connecting hole at a location other than the second curved surface 21. The first connecting hole and the second connecting hole are directly opposite each other. The first connecting hole and the second connecting hole are used for threaded connectors to be installed to lock the first clamp 10 and the second clamp 20, so that the first clamp 10 and the second clamp 20 can clamp the flexible film 30 to form the magnetized film 31.

[0119] Optionally, the first clamp 10 further includes a first mounting base, the first curved surface 11 is disposed on the first mounting base, and the first connecting hole is disposed on the first mounting base; the second clamp 20 further includes a second mounting base, the second curved surface 21 is disposed on the second mounting base, and the second connecting hole is disposed on the second mounting base.

[0120] In this embodiment, by providing a first connecting hole on the first clamp 10 except for the first curved surface 11, and a second connecting hole on the second clamp 20 except for the second curved surface 21, threaded connectors can be installed through the first and second connecting holes to lock the first clamp 10 and the second clamp 20 in opposite directions. This allows the first clamp 10 and the second clamp 20 to clamp the flexible film 30 into the magnetized film 31.

[0121] In one embodiment, step S200 specifically includes the following steps:

[0122] S210. The flexible film is disposed between the first curved surface of the first clamp and the second curved surface of the second clamp;

[0123] S220. The first abutting device abuts against the first clamp in a first direction, the first direction pointing from the first clamp directly towards the second clamp;

[0124] S230. The second abutting device abuts against the second clamp in a second direction, the second direction pointing from the second clamp directly towards the first clamp.

[0125] In this embodiment, by using a first abutting device to abut against the first clamp 10 along a first direction and a second abutting device to abut against the second clamp 20 along a second direction, the first clamp 10 and the second clamp 20 can clamp the flexible film 30 disposed therein in mutually opposing directions. This allows the flexible film 30 to be clamped into a magnetized film 31, so that the magnetized film 31 can be completely and tightly attached to the first curved surface 11 and the second curved surface 21. This ensures that the shape of the magnetized film 31 is completely consistent with the shape of the first curved surface 11 and the second curved surface 21, that is, it ensures that the magnetized film 31 has a preset three-dimensional curved surface shape. This is beneficial for obtaining a flexible magnetic film after magnetizing and flattening the magnetized film 31, and ensures that the preset magnetization pattern on the final flexible magnetic film meets the requirements.

[0126] Please see Figure 1-19In some embodiments, the preset magnetization pattern includes one or more magnetization features, in which the direction of all magnetization intensity vectors M continuously rotates and changes along one or more preset distribution directions, thereby making each magnetization feature in the preset magnetization pattern a magnetization pattern similar to a Helbeck magnet array, so that the magnetic field in the region where each magnetization feature is located can be enhanced on one side of the flexible magnetic film. It should be noted that the magnetization feature in this embodiment refers to a local magnetization unit in the preset magnetization pattern, and this local magnetization unit has an independent directional distribution of magnetization intensity vector M. The three-dimensional curved surface includes at least one curved surface unit, and each curved surface unit corresponds to one of the magnetization features, that is, the directional distribution of magnetization intensity vector M presented by the part of the film to be magnetized 31 corresponding to each curved surface unit on the finally formed flexible magnetic film is one of the magnetization features. The magnetization direction of the unidirectional uniform magnetic field is a normal-like direction that passes through the three-dimensional curved surface once. That is, the magnetization direction of the unidirectional uniform magnetic field points only from the outside of the three-dimensional surface to the inside of the three-dimensional surface, or only from the inside of the three-dimensional surface to the outside of the three-dimensional surface, without crossing the three-dimensional surface twice or multiple times. This ensures that the magnetic induction lines used for magnetization point only from the outside of the magnetized film 31 to the inside of the magnetized film 31, or only from the inside of the magnetized film 31 to the outside of the magnetized film 31. This ensures that the magnetization intensity vector M in the final preset magnetization pattern continuously rotates and changes along the shape contour of the magnetized film 31, thereby guaranteeing that each magnetization feature is a magnetization pattern similar to a Helbeck magnet array.

[0127] Since the magnetization direction of the unidirectional uniform magnetic field in this embodiment is a quasi-normal direction that passes through the three-dimensional curved surface once, the magnetization method described in this embodiment can be called normal magnetization.

[0128] For example, the surface unit can be a convex surface or a concave surface corresponding to the shape and size of the magnetization feature, so that the rotational variation law of the magnetization intensity vector M in each of the preset distribution directions corresponds to the variation law of a variation curve that makes up the convex surface or the concave surface. When it is necessary to determine the first surface 11 of the first fixture 10 and the second surface 21 of the second fixture 20, if the first surface 11 (or the second surface 21) is an outwardly convex surface, then the convex surface corresponding to the shape and size of the magnetization feature is set as the surface unit; if the first surface 11 (or the second surface 21) is an inwardly concave surface, then the concave surface corresponding to the shape and size of the magnetization feature is set as the surface unit. Here, "corresponds to" means that the boundary curve of the convex surface or the concave surface just coincides with the boundary line of the magnetization feature. The surface unit can be one of the common curved surfaces such as a spherical cap, ellipsoidal cap, sine wave surface, cosine wave surface, pyramidal surface, frustum surface, conical surface, or frustum surface, as long as it ensures that the rotational variation law of the magnetization intensity vector M in each preset distribution direction of the magnetization feature corresponds to the variation law of a variation curve that makes up the surface unit. Here, the sine wave surface (or cosine wave surface) refers to a regular surface obtained by rotating a sine wave curve (or cosine wave curve) of half a cycle around its central axis by 360°.

[0129] It is understandable that by setting the shape of the curved unit in this way, the rotational variation law of the magnetization intensity vector M in each preset distribution direction of the magnetization feature corresponds to the variation law of a variation curve that makes up the curved unit. This ensures that after obtaining the flexible magnetic film, the magnetization pattern of the region where each curved unit is located conforms to the definition of the magnetization feature. It should be noted that the "variation curve" mentioned here can actually be a broken line segment or a smooth curve, and is not strictly limited to being a smooth curve. By setting the curved unit of the three-dimensional surface and the magnetization direction of the unidirectional uniform magnetic field as in this embodiment, the shape of the three-dimensional surface can satisfy the requirements of all the magnetization features in the preset magnetization pattern.

[0130] By executing this embodiment, the three-dimensional surface can be easily determined based on the preset magnetization pattern and the magnetization direction of the unidirectional uniform magnetic field, that is, the shape of the first surface 11 can be determined, and then the shape of the second surface 21 can be determined according to the complementary relationship defined by Formula 1. Based on this, by executing steps S100-S400 provided in this embodiment, a flexible magnetic film can be successfully fabricated, and the preset magnetization pattern on the flexible magnetic film can have one or more of the aforementioned magnetization features, thereby enhancing the magnetic induction intensity on one side of the flexible magnetic film, which is beneficial to improving the force measurement sensitivity of the magnetic tactile sensor manufactured based on the flexible magnetic film.

[0131] Optionally, the boundary curve of the three-dimensional surface is determined based on the boundary contour of the preset magnetization pattern. The boundary curve of the three-dimensional surface refers to the boundary line used to enclose the bottom contour of the three-dimensional surface. Determining the boundary curve based on the boundary contour of the preset magnetization pattern ensures that the boundary contour of the magnetization pattern after the curved magnetic film is flattened into a flexible magnetic film is the boundary contour of the predefined preset magnetization pattern. It should be noted that, since the shape and boundary contour of the curved magnetic film itself will change during the process of flattening the curved magnetic film into a flexible magnetic film, the implementation of this embodiment is not intended to make the boundary curve of the three-dimensional surface directly coincide with the boundary contour of the preset magnetization pattern, but rather to consider the shape changes during the "flattening" process, so that the boundary contour of the flexible magnetic film obtained by flattening the curved magnetic film is the boundary contour of the preset magnetization pattern. This is the actual meaning of the aforementioned "determined based on...".

[0132] To more clearly illustrate the manufacturing method of the flexible magnetic film provided in this part of the embodiments, six specific embodiments are provided below based on different preset magnetization patterns, different shapes of three-dimensional curved surfaces, and different magnetization directions of unidirectional uniform magnetic fields, to further explain and illustrate the "normal magnetization" method.

[0133] First Embodiment

[0134] Please see Figure 4 and Figure 6-9 In the first embodiment, the preset magnetization pattern on the flexible magnetic film is a magnetization feature, and the boundary contour of the magnetization feature is circular. Along any radial direction of the circle, there exists a corresponding magnetization intensity vector M that rotates in the magnetization feature. The three-dimensional curved surface is a surface unit, and the surface unit is a hemispherical surface. The first curved surface 11 is an outwardly convex curved surface, specifically a convex surface in the shape of a hemispherical surface; the second curved surface 21 is an inwardly concave curved surface, specifically a concave surface in the shape of a hemispherical surface. The magnetization direction of the unidirectional uniform magnetic field is parallel to the height direction of the hemispherical surface, so that the magnetization direction of the unidirectional uniform magnetic field can only pass through the three-dimensional curved surface once. Since the first curved surface 11 and the second curved surface 21 are hemispherical, the magnetized film 31 clamped by the first clamp 10 and the second clamp 20 is also hemispherical. The magnetization direction of the unidirectional uniform magnetic field is from the inside of the film 31 to the outside of the film 31 to be magnetized. This magnetization method in the first embodiment can be called cohesive radial magnetization.

[0135] In the first embodiment, the flexible film 30 has a preset shape of circular and preset dimensions including a diameter of 4.0 mm and a thickness of 0.5 mm.

[0136] In the first embodiment, the flexible substrate is an elastic material. By selecting an elastic material as the flexible substrate, it is easier for the circular flexible film 30 to be clamped by the first clamp 10 and the second clamp 20 in the above step S200 to become a hemispherical magnetized film 31, and it is also easier to flatten the hemispherical curved magnetic film into a circular flexible magnetic film in the above step S400.

[0137] Please see Figure 6 , Figure 6 Each arrow indicates the direction of magnetization at the arrow's position when magnetizing the magnetized film 31, while the length of the arrow represents the magnitude of the magnetization intensity at that point within the plane of the flexible magnetic film. Please refer to... Figure 7-9 It can be observed that around the flexible magnetic film obtained by cohesive radial magnetization, the magnetic flux density Bz and the gradient of magnetic flux density variation in the Z-axis direction are visible. Bz / The z-axis follows a sinusoidal curve variation along any radial direction of the circle. In the first embodiment, since the flexible film 30 is circular with a diameter of 4.0 mm and a thickness of only 0.5 mm, the thickness of the flexible film is very small, and the magnetization state in the thickness direction (i.e., the Z-axis direction) can be approximately considered isotropic. Figure 4 As shown, the magnetization direction passes directly through the magnetized film 31 along the height direction of the hemisphere. Based on the principle of making the first included angle θ1 equal to the second included angle θ2, the curved magnetic film is unfolded into a flexible magnetic film after magnetization. This allows the magnetization intensity direction on the flexible magnetic film to exhibit a periodic, continuously rotating spatial distribution, meaning the magnetization intensity direction of the flexible magnetic film exhibits a sinusoidal curve variation characteristic. This results in a magnetization pattern similar to a Helbeck magnet array on the flexible magnetic film. This significantly enhances the magnetic field strength on one side of the flexible magnetic film, while the magnetic field strength on the other side cancels each other out, forming a typical unilateral magnetic field effect. Such a flexible magnetic film can achieve the maximum unilateral magnetic induction intensity and magnetic induction intensity gradient with the minimum magnet volume, which is beneficial for significantly improving the sensitivity of the magnetic tactile sensor after placing the magnetic induction chip on the side with enhanced magnetic induction intensity.

[0138] In some other embodiments, the curved surface unit can also be a sinusoidal waveform surface. In this case, the first curved surface is a convex curved surface in the shape of a sinusoidal waveform surface, and the second curved surface is a concave curved surface in the shape of a sinusoidal waveform surface. The film to be magnetized formed by the first and second clamps is also in the shape of a sinusoidal waveform surface. The magnetization direction of the unidirectional uniform magnetic field is parallel to the height direction of the sinusoidal waveform surface, so that the magnetization direction of the unidirectional uniform magnetic field can only pass through the three-dimensional curved surface once. The preset magnetization pattern on the flexible magnetic film thus obtained is also a magnetization feature with a circular boundary contour.

[0139] Second Embodiment

[0140] Please see Figure 5-9 The difference between the second embodiment and the first embodiment lies only in that the magnetization direction of the unidirectional uniform magnetic field points from the outside of the film 31 to the inside of the film 31 to be magnetized. This magnetization method in the second embodiment can be called radial diverging.

[0141] It is understood that the magnetization direction on the flexible magnetic film obtained through the second embodiment also exhibits a periodic, continuously rotating spatial distribution, meaning the magnetization direction of the flexible magnetic film exhibits a sinusoidal variation characteristic, thus creating a magnetization pattern similar to a Helbeck magnet array on the flexible magnetic film. This allows for a significant enhancement of the magnetic field strength on one side of the flexible magnetic film, while the magnetic field strength on the other side cancels each other out, forming a typical unilateral magnetic field effect. Such a flexible magnetic film can achieve the maximum unilateral magnetic induction intensity and magnetic induction gradient with a minimal magnet volume, thereby facilitating a significant improvement in the sensitivity of the magnetic tactile sensor after arranging the magnetic induction chip on the side with enhanced magnetic induction intensity.

[0142] Please see Figure 8 The magnetic flux density amplitudes of flexible magnetic films obtained by both cohesive radial magnetization and diffuse radial magnetization are exactly equal; the only difference is that the directions of the magnetic flux density on the same plane around the films are exactly opposite. Please refer to... Figure 9 By comparing the flexible magnetic films obtained by magnetizing the same circular magnetic film using three methods—the traditional uniform normal magnetization method, the cohesive radial magnetization direction of the first embodiment, and the divergent radial magnetization direction of the second embodiment—it can be observed that the magnetic induction intensity distribution of the three flexible magnetic films along the X-axis on the same plane around them is different. The results show that the flexible magnetic films obtained by the cohesive radial magnetization direction and the divergent radial magnetization direction exhibit different magnetic induction intensities Bz at their peak values ​​and their spatial gradients along the normal direction. Bz / Compared to traditional uniform normal magnetization methods, the magnetic flux density (z) is increased by 2-3 times. Furthermore, the closer the magnetization is to the center of the flexible magnetic film (corresponding to the vertex of the film to be magnetized), the greater the increase in magnetic flux density.

[0143] Third Embodiment

[0144] The third embodiment is based on the first embodiment.

[0145] Please see Figure 10 and Figure 12In the third embodiment, the magnetization feature is circular, and along any radial direction of the circle, there exists a corresponding magnetization intensity vector M that rotates and changes direction within the magnetization feature. The preset magnetization pattern on the flexible magnetic film includes multiple magnetization features arranged in a hexagonal close-packed (HCP) configuration.

[0146] The first curved surface 11 of the first clamp 10 includes a plurality of raised surfaces arranged in a hexagonal close-packed (HCP) configuration, wherein the raised surfaces are hemispherical. Correspondingly, the second curved surface 21 of the second clamp 20 is a concave curved surface, wherein the concave curved surface includes a plurality of recessed surfaces arranged in a hexagonal close-packed (HCP) configuration, wherein the recessed surfaces are hemispherical.

[0147] In the third embodiment, the magnetization direction of the unidirectional uniform magnetic field is parallel to the height direction of the hemisphere, so that the magnetization direction of the unidirectional uniform magnetic field can only pass through the three-dimensional curved surface once. Furthermore, the magnetization direction of the unidirectional uniform magnetic field points from the inside of the film 31 to the outside of the film 31 to be magnetized.

[0148] In the third embodiment, the preset shape of the flexible film 30 is circular, and the preset dimensions of the flexible film 30 include a thickness of 0.5 mm.

[0149] In the third embodiment, the flexible substrate is an elastic material. By selecting an elastic material as the flexible substrate, it is easier to clamp the circular flexible film into a magnetized film 31 comprising multiple hexagonal close-packed hemispherical surfaces through the first clamp 10 and the second clamp 20 in the above step S200, and it is also beneficial to flatten the curved magnetic film into a circular flexible magnetic film through the above step S400.

[0150] In the third embodiment, because the first curved surface 11 has a plurality of hemispherical protrusions arranged in a hexagonal close-packed (HCP) manner, and the second curved surface 21 has a plurality of hemispherical concave surfaces arranged in a hexagonal close-packed (HCP) manner, the flexible film 30 will become a shape including a plurality of hemispherical surfaces arranged in a hexagonal close-packed (HCP) manner after being clamped by the first clamp and the second clamp. In this embodiment, the magnetization direction of the unidirectional uniform magnetic field is parallel to the height direction of the hemisphere. The magnetization direction of the unidirectional uniform magnetic field points only from the inside to the outside of the film 31 to be magnetized, which is equivalent to magnetizing in the direction described in the first embodiment. The resulting flexible magnetic film will have multiple magnetization features arranged in a hexagonal close-packed (HCP) configuration. The magnetization intensity direction in each feature exhibits a periodic, continuously rotating spatial distribution, meaning the magnetization intensity direction in each feature exhibits a sinusoidal curve variation characteristic. Each magnetization feature is a magnetization pattern similar to a Helbeck magnet array. Therefore, the overall magnetization pattern on the flexible magnetic film in this embodiment is multiple magnetization patterns similar to a Helbeck magnet array arranged in a hexagonal close-packed (HCP) configuration. Such a flexible magnetic film is suitable for preparing magnetization patterns of multiple Helbeck magnet arrays arranged in an array.

[0151] In other embodiments, the first curved surface 11 of the first clamp 10 may be a concave curved surface, comprising a plurality of recessed surfaces arranged in a hexagonal close-packed (HCP) configuration, wherein the recessed surfaces are hemispherical. Correspondingly, the second curved surface 21 of the second clamp 20 may be a convex curved surface, comprising a plurality of raised surfaces arranged in a hexagonal close-packed (HCP) configuration, wherein the raised surfaces are hemispherical.

[0152] Fourth embodiment

[0153] Please see Figures 11-12 In the fourth embodiment, the difference from the third embodiment lies only in that the preset magnetization pattern includes multiple magnetization features arranged in an orthogonal grid. The first curved surface 11 of the first clamp 10 includes multiple raised surfaces arranged in an orthogonal grid, and the second curved surface 21 of the second clamp 20 includes multiple recessed surfaces arranged in an orthogonal grid.

[0154] In this embodiment, since the first curved surface 11 has multiple hemispherical protrusions arranged in an orthogonal grid pattern, and the second curved surface 21 has multiple hemispherical concave surfaces arranged in an orthogonal grid pattern, the flexible film 30 will become a shape including multiple hemispherical surfaces arranged in an orthogonal grid pattern after being clamped by the first clamp 10 and the second clamp 20. In this embodiment, the magnetization direction of the unidirectional uniform magnetic field is parallel to the height direction of the hemisphere. The magnetization direction of the unidirectional uniform magnetic field points only from the inside to the outside of the film 31 to be magnetized, which is equivalent to magnetizing in the direction described in the first embodiment. The resulting flexible magnetic film will have multiple magnetization features arranged in an orthogonal grid, and the magnetization intensity direction in each feature will exhibit a periodic, continuously rotating spatial distribution. That is, the magnetization intensity direction in each feature will exhibit a sinusoidal curve variation characteristic, and each feature will be a magnetization pattern similar to a Hellbeck magnet array. Therefore, the overall magnetization pattern on the flexible magnetic film in this embodiment is a series of magnetization patterns similar to a Hellbeck magnet array arranged in an orthogonal grid. Such a flexible magnetic film is suitable for preparing magnetization patterns of multiple Hellbeck magnet arrays arranged in an array.

[0155] Of course, in other similar embodiments different from the third and fourth embodiments, the first curved surface 11 can also be processed into a shape with multiple raised surfaces arranged in other ways, and the second curved surface 21 can be processed into a shape with multiple recessed surfaces arranged in other ways, so that both the raised and recessed surfaces are hemispherical, and the magnetization direction of the unidirectional uniform magnetic field is set to be parallel to the height direction of the hemisphere. Thus, after magnetization, a flexible magnetic film with multiple magnetization features arranged in the aforementioned way can be obtained, and the direction of magnetization intensity in each magnetization feature still exhibits a sinusoidal curve variation characteristic. By manufacturing a flexible magnetic film in this way, the arrangement can be preset as needed, thereby realizing the programming of the magnetization pattern of the Hellbeck magnet array on the flexible magnetic film, so that the magnetization pattern on the flexible magnetic film can be set according to actual needs.

[0156] Fifth embodiment

[0157] Please see Figure 13-14 In the fifth embodiment, the preset magnetization pattern on the flexible magnetic film is a magnetization feature. The boundary contour of the magnetization feature is annular, and along the width direction of the annulus, the directions of all magnetization intensity vectors M in the magnetization feature rotate, exhibiting a rotational variation pattern. The width direction of the annulus is the only preset distribution direction in which all magnetization intensity vectors M in the magnetization feature rotate.

[0158] In the fifth embodiment, the first curved surface 11 of the first clamp 10 and the second curved surface 21 of the second clamp 20 are both annular curved surfaces. The magnetization direction of the unidirectional uniform magnetic field is parallel to the height direction of the annular curved surface to ensure that it passes through the three-dimensional curved surface only once. At this time, the film to be magnetized 31 is also an annular curved surface, and the magnetization direction of the unidirectional uniform magnetic field points from the inside of the film to be magnetized 31 to the outside of the film to be magnetized 31, or from the outside of the film to be magnetized 31 to the inside of the film to be magnetized 31. The flexible substrate is an elastic material to support the flexible film 30 being clamped by the first clamp 10 and the second clamp 20 to become the film to be magnetized 31, and to support the curved magnetic film after magnetization to be flattened into the flexible magnetic film.

[0159] According to the fifth embodiment, the flexible magnetic film has a pre-set magnetization pattern that is ring-shaped, which can meet the specific requirement that the magnetic induction chip of the magnetic tactile sensor containing the flexible magnetic film needs to be arranged in a ring shape in certain situations. Furthermore, because the direction of all magnetization intensity vectors M rotates along the width of the ring, exhibiting a rotational variation law, a magnetization pattern similar to a Helbeck magnet array is also obtained on the flexible magnetic film. This allows the magnetic field strength on one side of the flexible magnetic film to be significantly enhanced, while the magnetic field strength on the other side cancels each other out, forming a typical unilateral magnetic field effect. This is beneficial for significantly improving the sensitivity of the magnetic tactile sensor after arranging the magnetic induction chip on the side with enhanced magnetic induction intensity.

[0160] Sixth Embodiment

[0161] Please see Figure 15-16 In the sixth embodiment, the preset magnetization pattern is a magnetization feature, which is rectangular. The direction of all magnetization intensity vectors M in the magnetization feature rotates only along the width direction of the rectangle (i.e., the X-axis direction in the figure). The width direction of the rectangle is the only preset distribution direction in which all magnetization intensity vectors M in the magnetization feature rotate.

[0162] In the manufacturing method of the flexible magnetic film provided in the sixth embodiment, the curved surface unit is a corrugated surface that extends along a one-dimensional direction and is wavy. The one-dimensional linear direction corresponds to the preset distribution direction (i.e., the width direction of the rectangle). The magnetization direction of the unidirectional uniform magnetic field is parallel to the height direction of the corrugated surface to ensure that it passes through the three-dimensional curved surface only once. At this time, the film to be magnetized 31 is also a corrugated surface shape. The magnetization direction of the unidirectional uniform magnetic field points from the inside of the film to be magnetized 31 to the outside of the film to be magnetized 31, or from the outside of the film to be magnetized 31 to the inside of the film to be magnetized 31.

[0163] According to the flexible magnetic film obtained in the sixth embodiment, the preset magnetization pattern on it is rectangular, and the direction of all magnetization intensity vectors M only rotates and changes along the width direction of the rectangle, exhibiting a rotational variation law. Therefore, a magnetization pattern similar to a Helbeck magnet array can also be obtained on the flexible magnetic film. This allows the magnetic field strength on one side of the flexible magnetic film to be significantly enhanced, while the magnetic field strength on the other side cancels each other out, forming a typical one-sided magnetic field effect. This is beneficial for significantly improving the sensitivity of the magnetic tactile sensor after arranging the magnetic induction chip on the side with enhanced magnetic induction intensity.

[0164] In the sixth embodiment, since the corrugated surface is a developable surface, elastic deformation is not required to complete the process of clamping the flexible film 30 into the magnetized film 31 and the process of flattening the curved magnetic film into the flexible magnetic film. The flexible substrate can be an elastic material or a non-elastic material.

[0165] In some other embodiments, the magnetization feature of the preset magnetization pattern can also be set as a rectangle, and the direction of all magnetization intensity vectors M in the magnetization feature rotates only along the length direction of the rectangle. In this case, the length direction of the rectangle is the only preset distribution direction in which all magnetization intensity vectors M in the magnetization feature rotate. The curved surface unit is a corrugated surface that extends along a one-dimensional direction and is wavy, and the one-dimensional linear direction is set corresponding to the preset distribution direction (i.e., the length direction of the rectangle). The magnetization direction of the unidirectional uniform magnetic field is parallel to the height direction of the corrugated surface to ensure that it passes through the three-dimensional surface only once. The film to be magnetized 31 is also a corrugated surface shape, and the magnetization direction of the unidirectional uniform magnetic field points from the inside of the film to be magnetized 31 to the outside of the film to be magnetized 31, or from the outside of the film to be magnetized 31 to the inside of the film to be magnetized 31.

[0166] Please see Figure 17-27 In some embodiments, the preset magnetization pattern includes one or more sets of positively magnetized regions and negatively magnetized regions. The positively and negatively magnetized regions within the same set are symmetrical about a boundary line, and the directions of any two magnetization intensity vectors M that are symmetrical about the boundary line are opposite. It should be noted that, based on the aforementioned symmetry, the direction variation of the magnetization intensity vector M within the same set of positively and negatively magnetized regions remains consistent along a direction perpendicular to the boundary line. For example, please refer to... Figure 17 The magnetization intensity vector M (i.e., the direction of the small arrow in the figure) of the positive magnetization region and the negative magnetization region rotates in the same direction (clockwise from left to right).

[0167] The three-dimensional surface includes at least one surface unit. Each surface unit corresponds to a set of positive magnetization regions and negative magnetization regions. Each surface unit consists of two surface sub-units that are symmetrical about the interface. The two surface sub-units correspond to the same set of positive magnetization regions and negative magnetization regions, respectively.

[0168] The dividing line is located on the interface, and the magnetization direction of the unidirectional uniform magnetic field is perpendicular to the tangent direction of the interface, so as to ensure that the unidirectional uniform magnetic field can point from one surface sub-unit of the same surface unit to another surface sub-unit. Thus, the magnetization direction of the unidirectional uniform magnetic field is perpendicular to the interface, pointing from the outside of the magnetized film 31 to the inside of the magnetized film 31 and then from the inside of the magnetized film 31 to the outside of the magnetized film 31. Therefore, after magnetizing the magnetized film 31 to obtain a curved magnetic film and flattening the curved magnetic film into the flexible magnetic film, one or more sets of positive magnetization regions and negative magnetization regions can be obtained on the flexible magnetic film, so that the positive magnetization region and the negative magnetization region of each set are symmetrical about the dividing line.

[0169] In this embodiment, the surface units of the three-dimensional surface are symmetrical about the interface, so a tangent plane can be determined at their top. Furthermore, since the magnetization direction of the unidirectional uniform magnetic field is perpendicular to the tangent direction of the interface, that is, the magnetization direction of the unidirectional uniform magnetic field is parallel to the tangent direction of the tangent plane at the top of the three-dimensional surface, the magnetization method described in this embodiment can be called tangential magnetization.

[0170] The flexible magnetic film obtained by implementing the embodiments in this section has a preset magnetization pattern that includes one or more sets of the forward magnetization regions and the reverse magnetization regions, which facilitates the formation of a multi-level textured magnetization pattern with high-frequency alternation on the flexible magnetic film. Flexible magnetic films with multi-level textured magnetization patterns can be widely used, especially in magnetic tactile sensors, where one or more magnetic induction chips can be used to accurately detect multi-dimensional contact forces.

[0171] For example, the surface unit is one of the following: spherical cap, ellipsoidal cap, sine wave surface, cosine wave surface, conical surface, and frustum. All such surfaces can be divided into two mutually symmetrical parts about a plane of symmetry, which corresponds to the above-mentioned "surface unit consists of two surface sub-units symmetrical about the interface," and therefore can all serve as surface units in this embodiment. It should be noted that the sine wave surface (or cosine wave surface) here refers to a regular surface obtained by rotating a sine wave curve (or cosine wave curve) of half a cycle around its central axis by 360°.

[0172] To more clearly illustrate the manufacturing method of the flexible magnetic film provided in this part of the embodiments, four specific embodiments are provided below based on different preset magnetization patterns, different shapes of three-dimensional curved surfaces, and different magnetization directions of unidirectional uniform magnetic fields, to further explain and illustrate the "tangential magnetization" method.

[0173] Seventh Embodiment

[0174] Please see Figure 17-19 In the seventh embodiment, the preset magnetization pattern on the flexible magnetic film is a set of positive magnetization regions and negative magnetization regions connected on both sides of the dividing line. The boundary contours of the positive magnetization regions and the negative magnetization regions are both semi-circular, and the positive magnetization regions and the negative magnetization regions are symmetrical about the dividing line. The directions of any two magnetization intensity vectors M that are symmetrical about the position of the dividing line are opposite.

[0175] The three-dimensional curved surface is a surface unit. The surface unit is a hemispherical surface, and it is positioned corresponding to the forward magnetization region and the reverse magnetization region. Each surface unit consists of two symmetrical surface sub-units about the interface, with the two sub-units corresponding to the forward magnetization region and the reverse magnetization region, respectively. Each of the two surface sub-units is a quarter-sphere. Correspondingly, the film to be magnetized is also hemispherical. The first surface 11 of the first clamp 10 is a convex surface, specifically a convex surface shaped like a hemispherical surface; the second surface 21 of the second clamp 20 is a concave surface, specifically a concave surface shaped like a hemispherical surface.

[0176] The magnetization direction of the unidirectional uniform magnetic field is parallel to the tangent plane at the top of the hemisphere. In this case, the magnetization direction of the unidirectional uniform magnetic field is also perpendicular to the tangent direction of the interface.

[0177] In the seventh embodiment, the flexible film 30 has a preset shape of circular and preset dimensions including a diameter of 4.0 mm and a thickness of 0.5 mm.

[0178] In the seventh embodiment, the flexible substrate is an elastic material. By selecting an elastic material as the flexible substrate, it is easier for the circular flexible film 30 to be clamped by the first clamp 10 and the second clamp 20 in the above step S200 to form a hemispherical magnetized film 31, and it is also easier to flatten the hemispherical curved magnetic film into a circular flexible magnetic film in the above step S400.

[0179] Please see Figure 17The magnetization direction of the unidirectional uniform magnetic field is perpendicular to the plane of symmetry of the curved surface unit (not shown in the figure), pointing from the outside of the magnetized film 31 to the inside of the magnetized film 31 and then from the inside of the magnetized film 31 to the outside of the magnetized film 31, that is, from one curved surface sub-unit to another. In the seventh embodiment, this magnetization method can be called tangential sinusoidal magnetization-A.

[0180] After obtaining the flexible magnetic film using the seventh embodiment, the magnetization intensity distribution on the circular flexible magnetic film is also circular, exhibiting a symmetrical distribution along a diameter. This diameter is perpendicular to the magnetization direction, corresponding to the symmetry plane of the aforementioned curved surface unit. The circular preset magnetization pattern is divided into two mutually symmetrical semicircular parts along this diameter; one semicircular part is the positive magnetization region, and the other semicircular part is the negative magnetization region. Please refer to... Figure 18-19 , Figure 18 and Figure 19 The magnetic flux density Bz and the gradient of magnetic flux density variation are shown in a plane with a height of Z = 0.6 mm around the flexible magnetic film. Bz / The distribution pattern of z also shows symmetry along a diameter.

[0181] Please continue reading. Figure 17 , Figure 17 The small arrow in the diagram indicates the direction of the magnetization vector M, which is determined by... Figure 17 It can be seen that the magnetization intensity of the flexible magnetic film still exhibits a periodic, continuous rotation (clockwise from left to right) spatial distribution along any radial direction of the circle, that is, it exhibits a sinusoidal curve variation characteristic. However, the directions of the magnetization intensity vector M at any two positions in the symmetrically distributed positive and negative magnetization regions along the axis of symmetry are opposite. Thus, a magnetization pattern similar to a Hellbeck magnet array can be achieved in a single positive or negative magnetization region. This allows the flexible magnetic film to increase the magnetic field strength on one side in a single positive or negative magnetization region, and the magnetic field strength increases in the two regions are opposite, making the two regions symmetrical to each other.

[0182] As can be seen, the flexible magnetic film obtained through the seventh embodiment has a magnetization pattern outline that is two semi-circular outlines symmetrical along the boundary line, which is equivalent to the result obtained by magnetizing a circular magnetic film using a conventional multi-pole magnetization device. The preset magnetization pattern on the flexible magnetic film obtained by performing the seventh embodiment is a set of mutually symmetrical positive and negative magnetization regions, which can be used to construct high-frequency alternating positive and negative magnetization textures.

[0183] Eighth embodiment

[0184] The only difference between the eighth embodiment and the seventh embodiment is that the magnetization direction of the unidirectional uniform magnetic field is opposite to that in the seventh embodiment.

[0185] Please see Figure 20 Although the magnetization direction of the unidirectional uniform magnetic field in the eighth embodiment is opposite to that in the seventh embodiment, it is still parallel to the tangent plane at the top of the hemisphere. The magnetization direction of the unidirectional uniform magnetic field is perpendicular to the symmetry plane of the curved unit, pointing from the outside of the magnetized film 31 to the inside of the magnetized film 31 and then from the inside of the magnetized film 31 to the outside of the magnetized film 31, that is, from one curved sub-unit of the curved unit to another curved sub-unit. In the third embodiment, this magnetization method can be called tangential sinusoidal magnetization-B.

[0186] The preset magnetization pattern of the flexible magnetic film obtained through the eighth embodiment is still a set of positive magnetization regions and negative magnetization regions symmetrically distributed along the boundary line, which can be used to construct high-frequency alternating positive and negative magnetization textures.

[0187] Ninth Embodiment

[0188] In the ninth embodiment, the preset magnetization pattern on the flexible magnetic film includes multiple sets of positive magnetization regions and negative magnetization regions connected on both sides of the dividing line. The positive magnetization regions and negative magnetization regions in the same set are symmetrical about the dividing line, and the directions of any two magnetization intensity vectors M that are symmetrical about the position of the dividing line are opposite.

[0189] Please see Figure 21-25 In the ninth embodiment, the three-dimensional surface is a continuous, smooth, and hexagonally symmetric parametric surface, composed of multiple continuously distributed surface units. The shapes of the first surface 11 and the second surface 21 are consistent with the three-dimensional surface, and the shapes of the first surface 11 and the surface unit 21 are as follows: Figure 23 As shown. The direction of the unidirectional uniform magnetic field is parallel to the tangent plane at the top of the curved surface unit.

[0190] Let the center-to-center distance between two adjacent surface elements on the three-dimensional surface along the arrangement direction be pitch, and let the height of the surface element be [missing information]. The three-dimensional surface can be described by the following equation 2:

[0191] [Formula 2]

[0192] In equation 2, It is the global amplitude coefficient, which is used to control the overall undulation and drop of the three-dimensional surface. With height The conversion relationship is as follows , , These represent the wavenumbers of the three-dimensional surface in the x-axis and y-axis directions, respectively, and are set to... The conversion relationship with the center pitch is as follows: ;set up The conversion relationship with the center pitch is as follows: .

[0193] It should be noted that the wave number is the magnitude of the wave vector component, which determines the spatial frequency, that is, the density of the undulating ripples. Control the rate of periodic change along the x-axis. The larger the value, the denser the ripples in the x-axis direction. Control the rate of periodic change along the y-axis. In Equation 2... , , These three cosine terms represent three plane waves propagating from different directions. Because the phases of these three cosine terms interfere with and superimpose, they create complex periodic bumps and depressions on a two-dimensional plane. Furthermore, in this embodiment, Therefore, it possesses special symmetry. The angle between the three cosine terms in space is exactly 120°, resulting in a three-dimensional surface that exhibits a perfect hexagonal honeycomb arrangement. In other words, the three-dimensional surface in this embodiment is essentially a continuous corrugated surface generated by the superposition of three cosine waves at 120° intervals under a hexagonal array.

[0194] Therefore, after magnetization using a unidirectional uniform magnetic field parallel to the top tangent plane of the curved surface unit, a closely arranged and periodically varying high-frequency magnetic field polarity texture can be obtained on the flexible magnetic film. The anisotropic magnetic period of this texture is completely controlled by the modulation of the aforementioned center-to-center pitch; the smaller the pitch, the shorter the magnetic period, and the higher the frequency of the polarity texture. Simultaneously, the peak magnetic flux density and magnetic flux density gradient on the surface of the flexible magnetic film are both related to the aforementioned height... They are positively correlated. Therefore, when manufacturing the flexible magnetic film using this embodiment, high-precision microfabrication techniques (such as precision CNC or micro / nano 3D printing) can be used to set the center-to-center pitch and height with greater precision. The value of [value] can be used to control the period, frequency, peak magnetic induction intensity, and magnetic induction intensity gradient of the preset magnetization pattern on the flexible magnetic film, thereby obtaining a flexible magnetic film with an extremely high frequency, submicron-level magnetization pattern. This high-frequency changing magnetization pattern has important applications in scenarios requiring complex magnetization patterns. Compared to the previous method that required multi-pole magnetization equipment to obtain such high-frequency textured magnetization patterns, the method in this embodiment can achieve this with a simple unidirectional uniform magnetic field and two ordinary clamps, simplifying the manufacturing process and processing cost of the flexible magnetic film, while ensuring that the accuracy of the magnetization pattern meets the requirements.

[0195] Furthermore, by introducing a constant of 1.5 as a zero offset and normalizing the denominator by 4.5 in Equation 2 above, it is mathematically guaranteed that regardless of the variables... How to adjust it so that the valley (lowest point) of the generated first surface will definitely fall at Z=0, and the peak (highest point) will definitely fall at Z= Place.

[0196] Furthermore, the ninth embodiment provides a specific example of controlling a preset magnetization pattern on a flexible magnetic film by parametrically designing the first curved surface 11 of the first fixture 10 and the second curved surface 21 of the second fixture 20, and manufacturing the first curved surface 11 and the second curved surface 21 through digital control. That is, when the first curved surface 11 and the second curved surface 21 can be precisely digitally controlled using precision machining technology, the characteristics of the preset magnetization pattern can be precisely controlled accordingly, so that the preset magnetization pattern can meet actual requirements.

[0197] Please see Figure 24-25 The preset magnetization pattern on the flexible magnetic film obtained through the ninth embodiment is similar to the high-frequency textured magnetization pattern formed by continuously performing forward and reverse magnetization on the flexible thin film 30. This high-frequency textured magnetization pattern can be applied to detection scenarios where a single magnetic induction chip senses multidimensional contact forces.

[0198] Preferably, in the ninth embodiment, the center-to-center distance pitch is set to 2.0 mm, and the height... =0.4mm.

[0199] Tenth Embodiment

[0200] Please see Figure 26-27In the tenth embodiment, the overall outline of the preset magnetization pattern on the flexible magnetic film is the same rectangle as in the sixth embodiment. Furthermore, the preset magnetization pattern in the tenth embodiment consists of multiple alternating forward and reverse magnetization regions arranged along a straight line. The boundary outlines of both the forward and reverse magnetization regions are elongated rectangles, and all of these elongated rectangles constitute the rectangle. Adjacent forward and reverse magnetization regions belong to the same group, and the forward and reverse magnetization regions in each group are connected on both sides of their boundary line and are symmetrical about the boundary line. Any two magnetization intensity vectors M that are symmetrical about the boundary line have opposite directions.

[0201] The three-dimensional surface is a corrugated surface extending along a straight line. The three-dimensional surface includes multiple surface units continuously arranged along the straight line. Each surface unit is a waveform unit (i.e., a waveform surface) of the corrugated surface extending along the straight line. The straight line is perpendicular to the boundary line between two adjacent rectangular strips. Correspondingly, the first surface 11 of the first clamp 10 and the second surface 21 of the second clamp 20 are both corrugated surfaces with the same shape as the three-dimensional surface.

[0202] The magnetization direction of the unidirectional uniform magnetic field is parallel to the tangent plane at the top of the (wave-shaped) curved surface unit; that is, the magnetization direction of the unidirectional uniform magnetic field is perpendicular to the tangent direction of the interface. In this embodiment, the film to be magnetized is also a corrugated curved surface shape. The unidirectional uniform magnetic field can point from the outside of the film to be magnetized 31 to the inside of the film to be magnetized 31 and then from the inside of the film to be magnetized 31 to the outside of the film to be magnetized 31.

[0203] Please see Figure 26 , Figure 26 This is a thermal map of the magnetic flux density Bz along the Z-axis in a plane with a height of Z=0.6mm around the flexible magnetic film obtained in the tenth embodiment. It can be seen that the thermal map of the magnetic flux density Bz consists of multiple long rectangles, with the magnetic flux density of adjacent long rectangles alternating between positive and negative and symmetrically distributed. Therefore, it can be concluded that the preset magnetization pattern on the flexible magnetic film is also composed of multiple long rectangles, with the magnetization intensity of adjacent long rectangles alternating between positive and negative and symmetrically distributed. These two adjacent long rectangles with alternating positive and negative and symmetrical distribution constitute a set of positive and negative magnetization regions.

[0204] The preset magnetization pattern on the flexible magnetic film obtained by performing the tenth embodiment consists of multiple sets of forward magnetization regions and reverse magnetization regions, and each set of forward magnetization regions and reverse magnetization regions is symmetrical along its boundary line, which can be used to construct high-frequency alternating forward and reverse magnetization textures.

[0205] It should be noted that although this application only provides the above ten embodiments, it does not mean that the preset magnetization pattern on the flexible magnetic film, the magnetization direction of the unidirectional uniform magnetic field, and the preset three-dimensional curved surface shape can only be the types specifically described in the above embodiments.

[0206] The second part of this application embodiment also provides a flexible magnetic film, including: a flexible substrate and magnetic particles distributed within the flexible substrate. The flexible substrate has a preset planar shape, and the magnetic particles form a preset magnetization pattern within the flexible substrate. The magnetization pattern is a distribution of the magnetization intensity vector M in the plane (where the flexible substrate is located).

[0207] The magnetization pattern includes at least one magnetization feature, wherein the direction of the magnetization intensity vector M is continuously rotated in the plane, thereby forming a magnetic field enhancement region on one side of the flexible magnetic film.

[0208] Alternatively, the magnetization pattern includes at least one set of positive magnetization regions and negative magnetization regions, wherein the positive magnetization regions and the negative magnetization regions in the same set are symmetrically distributed about a line of symmetry and such that the directions of the two symmetrical magnetization intensity vectors M are opposite.

[0209] The flexible magnetic film provided in the second part of this application, when the direction of the magnetization intensity vector M in its magnetization pattern can be continuously rotated in the plane, that is, the direction of magnetization intensity exhibits sinusoidal curve variation characteristics, will obtain a magnetization pattern similar to a Helbeck magnet array on the flexible magnetic film. This will create a magnetic field enhancement region on one side of the flexible magnetic film, forming a typical one-sided magnetic field effect. Such a flexible magnetic film can achieve the maximum one-sided magnetic induction intensity and magnetic induction intensity gradient with the minimum magnet volume, which is beneficial for significantly improving the sensitivity of the magnetic tactile sensor after arranging the magnetic induction chip on the side with enhanced magnetic induction intensity. When its magnetization pattern includes at least one set of forward magnetization region and reverse magnetization region, it is beneficial to obtain a high-frequency alternating multi-level textured magnetization pattern on the flexible magnetic film. Flexible magnetic films with multi-level textured magnetization patterns can be widely used, especially in magnetic tactile sensors, where one or more magnetic induction chips are set in the magnetic tactile sensor to accurately detect multi-dimensional contact forces.

[0210] As an implementation of the above manufacturing method, the third part of the embodiments of this application also provides a flexible magnetic film, which is manufactured by the manufacturing method of the flexible magnetic film in the above embodiments.

[0211] Since the flexible magnetic film provided in this application embodiment is manufactured by the manufacturing method of the flexible magnetic film in the above embodiments, by parametrically designing the shape of the first curved surface and the second curved surface and digitally controlling the processing of the first curved surface and the second curved surface, the magnetization pattern on the flexible magnetic film can be precisely controlled to be a predefined preset magnetization pattern, so that the flexible magnetic film can accurately meet the actual needs, and the manufacturing process of the flexible magnetic film can output complex magnetization patterns without the need for a multi-pole magnetization device, thereby reducing the development and manufacturing cost of the flexible magnetic film when changing the preset magnetization pattern.

[0212] Please see Figure 28 The fourth part of this application embodiment also provides a tactile sensor, including a circuit board 60 and a flexible magnetic film 32. The flexible magnetic film 32 is manufactured by the manufacturing method of the flexible magnetic film in the above embodiment. A Hall chip 50 is provided on the circuit board 60. The flexible magnetic film 32 is stacked on the circuit board 60 and fixedly disposed on the side of the Hall chip 50 away from the circuit board 60.

[0213] The tactile sensor provided in this embodiment, having a Hall chip 50 and a flexible magnetic film 32 stacked together, can change the magnetic induction intensity at the position of the Hall chip 50 due to the flexible deformation of the flexible magnetic film 32 when subjected to external contact force. This causes a change in the Hall signal (e.g., Hall voltage) detected by the Hall chip 50 at its location, thereby enabling the detection of external contact force by detecting the Hall signal. Furthermore, since the flexible magnetic film 32 is manufactured using the method described in the above embodiment, the first curved surface of the first clamp and the second curved surface of the second clamp can be configured according to the specific needs of the tactile sensor, so that the magnetization pattern on the final flexible magnetic film 32 is a predefined preset magnetization pattern to meet actual requirements. For example, a magnetization pattern similar to a Halbach magnet array can be obtained through the method described in the first embodiment above. This significantly enhances the magnetic field strength on the side of the flexible magnetic film 32 near the Hall chip 50, while the magnetic field strength on the side away from the Hall chip 50 cancels each other out. This maximizes the magnetic induction intensity and magnetic induction gradient of the flexible magnetic film 32 on the side near the Hall chip 50, which is beneficial for significantly improving the sensitivity of the tactile sensor. Furthermore, because this method of increasing the magnetic induction intensity and magnetic induction gradient does not increase the thickness of the magnetic film, it also facilitates the miniaturization and ultra-thin design of the tactile sensor.

[0214] In one embodiment, the circuit board 60 is a flexible printed circuit board (FPC), which can be easily mounted on curved surfaces, facilitating the attachment and acquisition of tactile information by the tactile sensor on complex curved surfaces. Furthermore, the thinner nature of the FPC compared to the printed circuit board (PCB) further reduces the thickness of the tactile sensor. For example, the thickness of the FPC can be 0.2 mm or 0.1 mm, compared to the current thickness of PCBs exceeding 0.5 mm. The Hall chip 50 is a single-axis Hall chip 50, which can also be thinner than a three-axis Hall chip 50; for example, a 0.2 mm Z-axis Hall chip 50 can be used. Multiple Hall chips 50 are arranged in an array on the flexible circuit board. This allows for three-dimensional force detection using a specific decoupling algorithm with multiple single-axis Hall chips 50 while maintaining a slim and lightweight design. Additionally, the flexible magnetic film 32 serves as a continuous force-magnetic conversion medium, working in conjunction with the array of multiple Hall chips 50 to achieve higher spatial resolution contact force detection, thereby increasing the contact force signal detection density.

[0215] In one embodiment, the tactile sensor further includes an elastic layer, which is directly fixed to the side of the Hall chip 50 opposite to the circuit board 60, and a flexible magnetic film 32 is directly fixed to the side of the elastic layer opposite to the Hall chip 50.

[0216] It is understandable that by setting an elastic layer between the flexible magnetic film 32 and the Hall chip 50, when the flexible magnetic film 32 is subjected to external contact force, the elastic deformation of the elastic layer can further increase the displacement of the flexible magnetic film 32 (the detection point) relative to the Hall chip 50, thereby increasing the Hall signal change of the Hall chip 50, which is beneficial to improving the signal detection accuracy of the tactile sensor.

[0217] In one embodiment, the elastic modulus of the elastic layer is lower than that of the flexible magnetic film 32. This allows the relative displacement of the flexible magnetic film 32 relative to the Hall chip 50 under contact force to be increased through the elastic layer with a lower elastic modulus, thereby increasing the Hall signal change of the Hall chip 50 and improving the force measurement accuracy of the tactile sensor. For example, the flexible substrate of the flexible magnetic film 32 can be made of silicone, and the elastic layer can also be made of silicone, with the elastic modulus of the elastic layer being lower than that of the flexible magnetic film 32.

[0218] In one embodiment, the elastic layer includes a planar base layer 41 directly connected to the flexible magnetic film 32 and a plurality of deformable portions 42 disposed on the planar base layer 41, with a gap between two adjacent deformable portions 42.

[0219] It is understood that by setting multiple deformable portions 42 and providing gaps between adjacent deformable portions 42, the cross-sectional area of ​​the layer containing the multiple deformable portions 42 (hereinafter referred to as the deformable layer) can be reduced. As a result, when the flexible magnetic film 32 is subjected to the same amount of contact force, the elastic layer as a whole can undergo more significant elastic deformation, thereby increasing the relative displacement of the flexible magnetic film 32 relative to the Hall chip 50, thereby improving the Hall signal change of the Hall chip 50, which is beneficial to improving the force measurement accuracy of the tactile sensor.

[0220] Optionally, the cross-sectional shape of the deformable portion 42 is one of a triangle, an isosceles trapezoid, a semicircle, and a semi-ellipse. It should be noted that the "cross-sectional shape" here refers to the cross-sectional shape obtained by cutting along the thickness direction of the elastic layer. By setting the cross-sectional shape of the deformable portion 42 to a triangle, an isosceles trapezoid, a hemisphere, or a semi-ellipse, when the elastic layer undergoes elastic deformation under contact force, the gradually decreasing cross-sectional area of ​​the deformable portion 42 increases the overall elastic deformation of the elastic layer. This facilitates increasing the relative displacement of the detection point on the flexible magnetic film 32 relative to the Hall chip 50, thereby further improving the force sensitivity of the tactile sensor and enabling it to be used for detecting minute contact forces. Furthermore, this shape of the deformable portion 42 (compared to ordinary sheet-like or block-shaped elastomers) is more prone to various elastic deformations such as compression, bending, torsion, and shearing. Therefore, from a structural mechanics perspective, it further reduces the external contact force threshold required for effective deformation, and also facilitates the tactile sensor's detection of extremely small contact forces in various directions.

[0221] Optionally, the cross-sectional shape of the deformable portion 42 is semi-circular or semi-elliptical. The semi-circular or semi-elliptical deformable portion 42, in addition to increasing the overall elastic deformation of the elastic layer, also has a smooth, arc-shaped transition surface, making it less prone to stress concentration. This prevents the deformable portion 42 from fracturing due to stress concentration when subjected to large contact forces, thus better ensuring the service life of the deformable portion 42 and making the elastic layer more durable.

[0222] Optionally, the elastic layer further includes a filler portion disposed in the gap, wherein the elastic modulus of the filler portion is lower than that of the deformable portion 42. By providing a filler portion with a lower elastic modulus in the gap between adjacent deformable portions 42, the elastic deformation of the elastic layer as a whole under contact force can still be maintained at a large amount based on the elastic deformation of the filler portion and the deformable portion 42. Furthermore, if the deformable portion 42 and the filler portion are made of the same material, the deformable portion 42 has a higher hardness than the filler portion, which also ensures that the elastic layer as a whole has good resilience.

[0223] In another embodiment, the elastic layer includes a first elastic layer and a second elastic layer stacked sequentially, wherein the elastic modulus of the first elastic layer is less than that of the second elastic layer.

[0224] In this embodiment, by setting the elastic layer as a stacked first elastic layer and a second elastic layer, it is possible to utilize the first elastic layer with a lower elastic modulus to ensure that the overall elastic layer has an elastic deformation amount that meets the requirements for detecting minute contact forces without making the elastic deformation amount too small. On the other hand, it is also possible to utilize the second elastic layer with a higher elastic modulus to ensure that the overall elastic layer has high resilience without making the rebound speed too slow. At the same time, the elastic layer adopts the solid elastomer material of this embodiment, which can maximize the advantage of the high degree of freedom of deformation of the flexible magnetic film 32 that is closely attached to the elastic layer, thereby obtaining extremely high spatial resolution of shear force (i.e., force parallel to the direction of the flexible magnetic film 32).

[0225] Obviously, the embodiments described above are only some embodiments of this application, not all embodiments. The accompanying drawings show preferred embodiments of this application, but do not limit the patent scope of this application. This application can be implemented in many different forms; rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this application's specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the scope of patent protection of this application.

Claims

1. A method of manufacturing a flexible magnetic film, characterized by, include: A flexible film is obtained, the flexible film being made of a flexible substrate filled with magnetic particles; The flexible film is clamped between the first clamp and the second clamp, so that the flexible film adheres to the mating surfaces of the first clamp and the second clamp under the action of clamping force, so as to be deformed into a magnetized film with a preset three-dimensional curved surface shape. A unidirectional uniform magnetic field is applied to the film to be magnetized to obtain a curved magnetic film; The curved magnetic film is flattened to obtain a flexible magnetic film with a preset magnetization pattern; The preset magnetization pattern is a predefined directional distribution of the magnetization intensity vector M on the flexible magnetic film. The mating surface shapes of the first clamp and the second clamp are determined according to the preset magnetization pattern and the magnetization direction of the unidirectional uniform magnetic field, such that: when the unidirectional uniform magnetic field is magnetized, each magnetization direction relative to the film to be magnetized corresponds one-to-one with the direction of the magnetization intensity vector M on the flexible magnetic film.

2. The method for manufacturing a flexible magnetic film according to claim 1, characterized in that, The preset magnetization pattern includes at least one magnetization feature, in which the direction of all magnetization intensity vectors M continuously rotates and changes along one or more preset distribution directions; the three-dimensional surface includes at least one surface unit, each surface unit corresponding to one of the magnetization features; the magnetization direction of the unidirectional uniform magnetic field is a normal-like direction that passes through the three-dimensional surface once.

3. The method of manufacturing a flexible magnetic film according to claim 2, wherein The curved surface unit is a hemispherical or sinusoidal wave surface, the boundary contour of the magnetization feature is circular, and along any radial direction of the circle, there exists a magnetization intensity vector M whose direction continuously rotates within the magnetization feature, and the flexible substrate is an elastic material. Alternatively, the surface unit is a toroidal surface, the boundary contour of the magnetization feature is annular, and the direction of all magnetization intensity vectors M within the magnetization feature continuously rotates and changes along the width direction of the annular shape; the flexible substrate is an elastic material. Alternatively, the surface unit is a corrugated surface extending along a one-dimensional direction, the boundary contour of the magnetization feature is a rectangle, the width direction or length direction of the rectangle is a reference direction corresponding to the one-dimensional direction, and the direction of all magnetization intensity vectors M within the magnetization feature rotates continuously only along the reference direction.

4. The method of manufacturing a flexible magnetic film according to claim 3, wherein The preset magnetization pattern includes multiple magnetization features, which are arranged on the flexible magnetic film in a hexagonal close-packed manner or an orthogonal grid manner.

5. The method of manufacturing a flexible magnetic film according to claim 1, wherein The preset magnetization pattern includes at least one set of positive magnetization regions and negative magnetization regions. The positive and negative magnetization regions in the same set are symmetrical about a boundary line, and the directions of any two magnetization intensity vectors M that are symmetrical about the boundary line are opposite. The three-dimensional surface includes at least one surface unit. Each surface unit corresponds to one set of positive and negative magnetization regions. Each surface unit consists of two surface sub-units that are symmetrical about the interface. The two surface sub-units correspond to the same set of positive and negative magnetization regions, respectively. The magnetization direction of the unidirectional uniform magnetic field is perpendicular to the tangent direction of the interface.

6. The method of manufacturing a flexible magnetic film according to claim 5, wherein The surface unit is one of the following: spherical cap surface, ellipsoidal cap surface, sinusoidal wave surface, conical surface, and frustum surface.

7. The method of manufacturing a flexible magnetic film according to claim 5, wherein The three-dimensional surface includes multiple surface units arranged continuously along a straight line. Each surface unit is a wave unit of a corrugated surface extending along the straight line. Both the positive magnetization region and the negative magnetization region are long rectangles. The boundary line between two adjacent long rectangles is perpendicular to the straight line. The preset magnetization pattern is composed of multiple positive magnetization regions and negative magnetization regions arranged alternately along the straight line.

8. The method of manufacturing a flexible magnetic film according to claim 5, wherein Let the center-to-center distance between two adjacent surface elements on the three-dimensional surface along the arrangement direction be pitch, and let the height of the surface element be [value missing]. The three-dimensional surface can be described by the following equation 2: [Equation 2] In equation 2, It is the global amplitude coefficient. With height The conversion relationship is as follows , , These represent the wavenumbers of the three-dimensional surface in the x-axis and y-axis directions, respectively, and are set to... The conversion relationship with the center pitch is as follows: ,set up The conversion relationship with the center pitch is as follows: .

9. The method of manufacturing a flexible magnetic film according to claim 1, wherein The thickness of the flexible film is less than 1 mm; the spatial period of the preset magnetization pattern is 0.1 mm to 1 mm; and the mating surfaces of the first fixture and the second fixture are processed by fused deposition modeling technology. Alternatively, the spatial period of the preset magnetization pattern is 1μm~100μm, and the mating surfaces of the first fixture and the second fixture are processed by photopolymerization molding technology or CNC machine tool processing technology.

10. The method of manufacturing a flexible magnetic film according to claim 1, wherein The mating surfaces of the first fixture and the second fixture are respectively a convex curved surface and an inwardly concave curved surface, and they satisfy the complementary relationship defined by the following formula 1. [Equation 1] 1 2 In Equation 1, and Let represent the surface functions of the convex and concave surfaces, respectively. This indicates the height of the convex surface. 1 indicates that the convex surface and the concave surface are in the corresponding Assembly clearance at coordinate position, 2 indicates that the film to be magnetized is in the corresponding The thickness value at the coordinate position.

11. A flexible magnetic film, characterized by, include: Flexible substrate; as well as Magnetic particles distributed within the flexible matrix; The flexible substrate has a preset planar shape, and the magnetic particles form a preset magnetization pattern within the flexible substrate. The magnetization pattern is a directional distribution of the magnetization intensity vector M in the plane. The magnetization pattern includes at least one magnetization feature, wherein the direction of the magnetization intensity vector M is continuously rotated in the plane, thereby forming a magnetic field enhancement region on one side of the flexible magnetic film. Alternatively, the magnetization pattern includes at least one set of positive magnetization regions and negative magnetization regions, wherein the positive magnetization regions and the negative magnetization regions in the same set are symmetrically distributed about a line of symmetry and such that the directions of the two symmetrical magnetization intensity vectors M are opposite.

12. A flexible magnetic film, characterized by The flexible magnetic film is manufactured by the manufacturing method of the flexible magnetic film according to any one of claims 1-10.

13. A tactile sensor characterized by, The invention includes a circuit board and a flexible magnetic film, wherein the flexible magnetic film is manufactured by the manufacturing method of the flexible magnetic film according to any one of claims 1-10, a Hall chip is provided on the circuit board, the flexible magnetic film is stacked on the circuit board, and the flexible magnetic film is fixedly disposed on the side of the Hall chip opposite to the circuit board.

14. The tactile sensor according to claim 13, characterized in that, The circuit board is a flexible circuit board, the Hall chip is a single-axis Hall chip, and multiple Hall chips are arranged in an array on the flexible circuit board.

15. The tactile sensor of claim 13, wherein, The tactile sensor also includes an elastic layer, which is directly fixed to the side of the Hall chip facing away from the circuit board, and the flexible magnetic film is directly fixed to the side of the elastic layer facing away from the Hall chip.

16. The tactile sensor according to claim 15, characterized in that, The elastic layer includes a planar base layer directly connected to the flexible magnetic film and a plurality of deformable portions disposed on the planar base layer, with a gap between two adjacent deformable portions.

17. The tactile sensor of claim 16, wherein, The cross-sectional shape of the deformable part is triangular, isosceles trapezoidal, semicircular, or semi-elliptical.

18. The tactile sensor of claim 16, wherein, The elastic layer further includes a filling portion, which is disposed in the gap, and the elastic modulus of the filling portion is lower than the elastic modulus of the deformable portion.

19. The tactile sensor of claim 15, wherein, The elastic layer includes a first elastic layer and a second elastic layer stacked sequentially, wherein the elastic modulus of the first elastic layer is less than that of the second elastic layer.

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