Magnetic flux generating member and actuator

Abstract

This magnetic flux generating member has a base material and a magnetic film formed on a surface of the base material. A single one of the magnetic film has a first region and a second region that are magnetized in differing directions.

Description

Magnetic flux generating member and actuator

[0001] This invention relates to a magnetic flux generating member and an actuator.

[0002] Conventional lens actuators drive the lens unit by bonding a thin magnet to the inner surface of a fixed frame and using the magnetic interaction with coils positioned opposite it (see, for example, Patent Document 1). While this enables autofocus and image stabilization, the configuration, which individually fixes multiple magnets, is prone to assembly errors, and the need to provide magnets in each direction increases the number of parts and man-hours. Furthermore, there are limitations to thinning a block magnet by cutting it, and it is practically impossible to process it to less than about 0.5 mm, thus limiting miniaturization and weight reduction. Bonded magnets offer excellent shape flexibility, but the resin content reduces magnetic flux density, making them unsuitable for high-driving force applications. Moreover, thin magnets are heavy and are generally placed in fixed parts, in which case the leakage magnetic field to the outside is large and prone to interference with surrounding equipment. In addition, since the paired coils are placed on the movable part side, heat dissipation is insufficient, making it difficult to pass large currents and limiting the improvement of responsiveness.

[0003] Japanese Patent Publication No. 2010-224489

[0004] This invention has been made in view of the above-mentioned problems, and aims to provide a compact, lightweight, highly efficient, and reliable magnetic flux generating member and an actuator using the same, while eliminating constraints on assembly and processing.

[0005] The magnetic flux generating member of this disclosure comprises a base material and a magnetic film formed on the surface of the base material, wherein one of the magnetic films has a first region and a second region magnetized in different directions.

[0006] The sensor of this disclosure comprises the magnetic flux generating member and at least one magnetic sensor or coil positioned to be magnetically interactable with the magnetic film.

[0007] The actuator of the present disclosure comprises a fixed portion and a movable portion, wherein one of the fixed portion and the movable portion has the magnetic flux generating member, and the other of the fixed portion and the movable portion has a coil positioned to be magnetically interactable with the magnetic film.

[0008] According to the present invention, it is possible to provide a compact, lightweight, highly efficient, and reliable magnetic flux generating member and an actuator using the same, while eliminating constraints on assembly and processing.

[0009] This is a scanning electron microscope (SEM) image showing a cross-section of the magnetic flux generating member of the present disclosure. This is a cross-sectional view showing one embodiment of the actuator for a miniature camera of the present disclosure. This is a cross-sectional view showing one embodiment of multipole magnetization of a magnetic film for a miniature camera actuator. This is a cross-sectional view showing an embodiment of the laminated structure of a substrate and a magnetic film. This is a perspective view of the actuator for a miniature camera shown in Figure 2A. This is a perspective view of the movable part of Figure 2A seen from the lens unit side. This is a perspective view of the movable part of Figure 2A seen from the image sensor side. This is a perspective view of the fixed part of Figure 2A seen from the lens unit side. This is a perspective view showing the internal structure of the fixed part of Figure 2G. This is a cross-sectional view showing an example in which a magnetic film is provided on the fixed part of the actuator for a miniature camera. This is a cross-sectional view showing another example in which a magnetic film is provided on the fixed part of the actuator for a miniature camera. This is a cross-sectional view showing another embodiment of the actuator for a miniature camera of the present disclosure. This is a perspective view of the actuator for a miniature camera shown in Figure 4A with the lens unit removed. This is a perspective view of the movable part of Figure 4A seen from the lens unit side. This is a perspective view of the fixed part of Figure 4A seen from the lens unit side. This is a cross-sectional view showing another embodiment of the actuator for a small camera (an example in which the arrangement of the lens unit and image sensor is reversed from that of Figure 4A). This is a diagram showing one step in the method of forming a magnetic film on the outer surface of the movable part, showing the state in which a substrate made of Co blocks has been prepared. This is a diagram showing one step in the method of forming a magnetic film on the outer surface of the movable part, showing SmCo on the surface of the substrate ２This shows the state in which a magnetic film has been formed. This is a diagram showing one step in the method of forming a magnetic film on the outer surface of the movable part. This shows the state in which, after forming a magnetic film on the surface of the substrate, the substrate is cut into a predetermined shape to obtain a movable part having a magnetic film. This is a diagram showing the state in which a lens unit is attached to the inside of the movable part obtained by the steps in Figures 6A to 6C to form the movable part. This is a diagram showing one step in the method of forming a magnetic film on the inner surface of the fixed part, and shows the state in which a cobalt block has been prepared as the substrate. This is a diagram showing one step in the method of forming a magnetic film on the inner surface of the fixed part, and shows the state in which a base member that does not contain transition metal elements has been deposited on the surface of the substrate. This is a diagram showing one step in the method of forming a magnetic film on the inner surface of the fixed part. This shows the state in which the base member is cut into a predetermined shape to obtain a fixed part having a cobalt film on its inner surface, and this cobalt film becomes the substrate for forming the magnetic film. This is a diagram showing one step in the method of forming a magnetic film on the inner surface of the fixed part, and shows SmCo on the cobalt film on the inner surface of the fixed part ２ This shows the state after a magnetic film has been formed. This figure shows the state after the fixing part has been cut to a predetermined final shape by an end mill or the like, after a magnetic film has been formed on the inner surface of the fixing part.

[0010] The embodiments of the present invention (hereinafter referred to as "the present disclosure") will be described in detail below, but the present invention is not limited thereto, and various modifications are possible without departing from its essence. In addition, in the drawings attached to this specification, the scale and aspect ratios of the dimensions may be changed and exaggerated from those of the actual objects for the convenience of illustration and ease of understanding.

[0011] 1. Magnetic Flux Generating Member Figure 1 shows a scanning electron microscope (SEM) image of a cross-section of the magnetic flux generating member. As shown in Figure 1, the magnetic flux generating member 1 of this disclosure comprises a base material 20 and a magnetic film 10 formed on the surface of the base material 20. Here, the base material 20 is made of cobalt (Co) with corners, and the surface of the base material 20 is made of a samarium-cobalt-based magnetic film 10 (for example, Sm ２ Co ７ SmCo ５ Sm ２ Co １７ (etc.) are directly formed.

[0012] Thus, the magnetic film 10 of the present disclosure may be formed directly on the surface of the substrate 20. "Directly" means that there is no intervening layer made of a non-magnetic material such as an oxide layer, a resin layer, or an adhesive layer thicker than the resolution of 0.5 to 4 nm observable by a scanning electron microscope (SEM) between the substrate 20 and the magnetic film 10.

[0013] Further, as shown in FIG. 1, one magnetic film 10 of the present disclosure has a first region 11 and a second region 12 magnetized in different directions. That is, the magnetic film 10 of the present disclosure is a magnetic film 10 having an integral structure with portions magnetized in two predetermined directions, and by the first region 11 and the second region 12 forming magnetic poles in different directions from each other, it becomes possible to generate multiple types of magnetic flux actions from one magnet.

[0014] Conventionally, thin magnetic plates, ring-shaped magnets, etc. were individually fixed to each surface of the substrate 20, and one or more magnets were required for each function of the substrate 20. However, as described above, in the magnetic flux generating member 1 of the present disclosure, a single magnetic film 10 is integrally formed on the substrate 20, so that multiple functions can be realized by one member. Therefore, simplification of the assembly process and reduction of the number of parts can also be achieved.

[0015] The magnetization directions in the first region 11 and the second region 12 may be at any angle that is not parallel to each other. For example, they may have opposite polarities (directions inverted by 180°), or may be in orthogonal directions (an angular difference of 90°). Further, the first region 11 and the second region 12 are formed adjacent and continuously, and can be formed by anisotropic magnetization in one magnetic film 10. As a whole, the magnetic film 10 has a configuration in which multiple functions can be exhibited from one magnetic film 10 based on the difference in the magnetization directions of such multiple regions.

[0016] In the magnetic flux generating member 1 of the present disclosure, the arrangement forms of the first region 11 and the second region 12 can take various forms according to the shape of the substrate 20.

[0017] In one aspect, when the base material 20 has a plurality of surfaces whose planes are orthogonal to each other, for example, the first surface 21 and the second surface 22 in FIG. 1, a single magnetic film 10 is formed across the plurality of surfaces. When the magnetic film 10 is continuously coated up to the first surface 21, the second surface 22 of the base material 20, and the corner portions connecting them, the portion covering the first surface 21 of the film becomes the first region 11, and the portion covering the second surface 22 becomes the second region 12. In this configuration, the first region 11 and the second region 12 are located on different surfaces of the base material 20 and are magnetized in different directions. That is, to put it another way, the first region 11 is magnetized so as to relatively move the base material 20 in the first direction when receiving an external magnetic field, and the second region 12 is magnetized so as to relatively move the base material 20 in a second direction different from the first direction when receiving an external magnetic field. Thereby, for example, by changing the magnetization direction between the first region 11 formed on one main surface (bottom surface) of the base material 20 and the second region 12 formed on the side surface orthogonal thereto, it becomes possible to impart a magnetic flux action in different axial directions to the base material 20.

[0018] In another aspect, on a single plane of the base material 20, the first region 11 may be provided in a part of the magnetic film 10, and the second region 12 may be provided in another part. That is, the first region 11 and the second region 12 magnetized in different directions within the same plane may be formed in one magnetic film 10. Specifically, by magnetizing one end side of the magnetic film 10 upward in the N - pole direction and the other end side downward in the N - pole direction (upward in the S - pole direction) on a flat surface of the base material 20, magnetic - pole regions facing opposite to each other within the same plane can be realized. With such a multi - pole magnetized magnetic film 10, it becomes possible to form a plurality of magnetic - pole patterns with a single film on the surface of the base material 20.

[0019] Alternatively, even when the base material 20 forms a curved surface, similarly, on the inner curved surface of the base material forming the curved surface, the one - end side and the other - end side of the magnetic film 10 may be provided so as to be magnetized in opposite directions.

[0020] The magnetization direction of the magnetic film 10 is not particularly limited, but for example, it may be a direction substantially perpendicular to the surface of the substrate 20. For example, the first region 11 may be magnetized perpendicularly upward with respect to the surface of the substrate 20, and the second region 12 may be magnetized perpendicularly downward with respect to the surface of the substrate 20. Alternatively, in yet another embodiment, the first region 11 may be magnetized in the direction normal to the surface of the substrate 20, and the second region 12 may be magnetized in the plane direction of the substrate 20. Or, in yet another embodiment, the first region 11 may be magnetized in an arbitrary plane direction of the substrate 20, and the second region 12 may be magnetized in a plane direction of the substrate 20 different from that of the first region 11.

[0021] The thickness of the magnetic film 10 may be determined considering the magnetic flux density required for functional expression and constraints on film formation technology. In this disclosure, the thickness of the magnetic film 10 is preferably 10 to 300 μm, 100 to 300 μm, or 150 to 300 μm. By having the thickness of the magnetic film 10 within the above range, film formation is easy and sufficient magnetic force can be generated.

[0022] The material of the base material 20 is not particularly limited and can be widely used, ranging from magnetic (ferromagnetic) materials to non-magnetic materials. Among these, soft magnetic materials are preferred. As a result, the base material 20 acts as a shield, which suppresses leakage of magnetic flux outside the device. Furthermore, in actuators and the like described later, the magnetic flux flowing through the coil increases, allowing for a greater driving force.

[0023] Such a substrate 20 is not particularly limited, but examples include those containing Co, Fe, Ni, Mo, Ta, Nb, FeCo, CoCr, CoCrMo, etc. Furthermore, the substrate 20 may have the same transition metal elements as the transition metal elements contained in the magnetic film 10. Alternatively, the substrate 20 may be a base member on which a film of the above Co, etc., is formed. Examples of base members include Mo plates.

[0024] Alternatively, the base material 20 may be a non-magnetic material such as silicon, resin, or ceramics. When the base material 20 is a non-magnetic material, the magnetic flux from the magnetic film 10 is open to the surroundings, but a configuration may be used in which a magnetic material acting as a yoke is placed on the back side of the magnetic film 10 to control the magnetic flux as needed.

[0025] The shape of the base material 20 is not particularly limited, and for example, it may be rectangular parallelepiped, columnar, box-shaped, hollow, or plate-shaped. Further, the surface of the base material 20 on which the magnetic film 10 is formed may be a flat surface, a convex curved surface or a concave curved surface, or may be a corner.

[0026] As the material constituting the magnetic film 10, a rare earth element and a transition metal element may be used. In particular, a magnet material having a composition containing samarium (Sm) or neodymium (Nd) as the rare earth element and cobalt (Co) or iron (Fe) as the transition metal element is desirable. The magnetic film 10 composed of these is a typical rare earth-transition metal-based hard magnetic material, for example, Sm-Co-based (SmCo alloy) or Nd-Fe-B-based (Nd ２ Fe １４ B-based alloy) magnet can be mentioned.

[0027] As the magnet phase of the specific magnetic film 10, SmCo represented by the composition formula RT ５ (R = rare earth element, T = transition metal element), Sm represented by the composition formula R ５ type of crystal phase, R ２ T １７ represented by Sm ２ Co １７ type, Sm ２ Fe １７ type of crystal phase, Nd ２ Fe １７ type of crystal phase, NdFe represented by the composition formula RT １２ represented by, and further R １２ T ２ T １７ N ３ A crystal phase in which nitrogen is introduced to enhance magnetic properties like that of (e.g., Sm ２ Fe １７ N ３ ) etc. can be mentioned. Since the rare earth-transition metal magnet material has strong uniaxial magnetic anisotropy and is excellent in demagnetization resistance, and can maintain a high coercive force even when made into a thin film or a thick film, it is suitable for the magnetic film 10 of the present disclosure.

[0028] Furthermore, the magnetic film 10 containing rare earth elements and transition metal elements may have a concentration gradient (composition gradient) of transition metal elements within the film (see Figure 1). For example, in the thickness direction of the magnetic film 10, the first concentration of transition metal elements on the substrate 20 side and the second concentration of transition metal elements on the opposite side of the substrate 20 may differ by a predetermined proportion or more. In this case, the first concentration may be lower than the second concentration by a predetermined proportion or more, or the first concentration may be higher than the second concentration by a predetermined proportion or more. The first and second concentrations can be defined as the ratio of the number of transition metal elements to the total number of atoms (100%) of rare earth elements and transition metal elements.

[0029] The above predetermined ratio, i.e., the absolute difference between the first concentration and the second concentration, may preferably be 0.01% or more, 0.05% or more, 0.07% or more, 0.09% or more, 0.10% or more, 0.12% or more, or 0.15% or more. Alternatively, the above predetermined ratio may preferably be 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, 5% or less, 2% or less, 1% or less, 0.7% or less, 0.5% or less, or 0.3% or less.

[0030] A compositional gradient within the film can be achieved by methods such as changing the target composition over time during sputter deposition or by tilting the elemental distribution through diffusion treatment.

[0031] 2. Operation of the Magnetic Flux Generating Member As described above, the magnetic flux generating member 1 of this disclosure has multiple regions in a single magnetic film 10 which are magnetized in different directions, and therefore the magnetic flux generated from a single magnetic film 10 can produce two or more different physical effects. That is, the magnetic film 10 of this disclosure functions as a multi-functional magnetic member that performs two or more roles with a single unit. Specifically, the magnetic flux generated from a single magnetic film 10 may have two or more functions selected from the group consisting of: a function to move the base material 20 along an arbitrary axial direction, a function to rotate the base material 20 around an arbitrary axis, a function to detect the axial motion of the base material 20, a function to detect the rotational motion of the base material 20, a function to fix the base material 20 in a predetermined position, a function to attract a moving body separate from the base material 20, and a function to repel a moving body separate from the base material 20.

[0032] In the following, examples are given of a single magnetic film 10 having multiple functions.

[0033] 2.1. Dual-axis motion of the substrate The first region 11 and the second region 12, which are magnetized in different directions, can be provided with a function to drive (move) the substrate 20 in a desired direction. Since the first region 11 and the second region 12 are magnetized in different directions, it is possible to move the substrate 20 relative to each other in different directions by changing the direction of the externally applied magnetic field or the coil arrangement. For example, the first region 11 may be magnetized so as to push or pull the substrate 20 up in a certain axial direction (first direction) when subjected to an external magnetic field, and the second region 12 may be magnetized so as to move the substrate 20 in a direction different from the first direction (second direction) when subjected to an external magnetic field. In this way, it is possible to provide two or more functions that generate translational motion of the substrate 20 along different axes, and as a result, multi-degree-of-freedom driving can be realized for a single substrate 20. For example, if the magnetic film 10 covers multiple surfaces of the substrate 20 (for example, surfaces corresponding to the X, Y, and Z axes), a single magnetic film 10 can impart motion along up to three orthogonal axes, making it possible to realize three types of drive functions that move the substrate 20 in three axial directions.

[0034] Furthermore, by magnetizing the magnetic film 10 with multiple polarities on the side surface of the substrate 20, and also forming a magnetic film 10 on the bottom surface of the substrate 20, it is possible to simultaneously provide two driving functions: rotation (rotation around a certain axis) and linear motion (translational movement along that axis), such as a rotational driving function by the magnetic film 10 on the side surface and a vertical linear driving function by the magnetic film 10 on the bottom surface. In this case, by magnetizing the first region 11 and the second region 12 on the side surface as N and S poles, and applying current to coils arranged around it to create a rotating magnetic field, the substrate 20 can be rotated, while simultaneously applying a vertical magnetic field from another coil to attract and repel the bottom magnetic film 10, thereby moving the substrate 20 up and down. As described above, the magnetic flux generating member 1 of this disclosure can provide a single substrate 20 with multiple degrees of freedom of motion in multiple axial directions, and a complex actuator mechanism can be constructed with a small number of parts.

[0035] 2.2. Detection of the Position and Orientation of the Substrate Furthermore, the magnetic flux generating member 1 of this disclosure can also be used as a sensor to detect the position and orientation of the substrate 20 by having a first region 11 and a second region 12 that are magnetized in different directions. For example, by placing a magnetic sensor (such as a Hall element or a magnetoresistive element) opposite the magnetic film 10, it is possible to detect changes in the strength and polarity of the magnetic flux generated from the magnetic film 10. By calculating the relative distance between the substrate 20 equipped with the magnetic film 10 and the sensor based on the magnetic field strength detected by the magnetic sensor, it is possible to measure the position (displacement) of the substrate 20 non-contact. In particular, if the magnetic film 10 of this disclosure is made to generate a strong magnetic flux in the thickness direction, the amount of change in magnetic field strength is large even when the substrate 20 moves with a minute stroke, and highly accurate displacement detection can be performed.

[0036] Furthermore, if the magnetic film 10 is multi-pole magnetized, it becomes possible to measure the rotation angle and rotation speed by detecting changes in the direction of the magnetic poles and the passage of multiple poles when the substrate 20 rotates. For example, if multiple Hall elements are provided around the magnetic film 10 (formed in a ring shape and multi-pole magnetized in the radial direction) attached to the substrate 20, the passage of each magnetic pole as the substrate 20 rotates can be detected sequentially, thus providing a function to detect the rotational motion (rotational position and speed) of the substrate 20 with high precision.

[0037] Furthermore, by arranging both a coil and a magnetic sensor opposite the magnetic film 10, it is possible to combine both the functions of driving (actuator) and position detection (sensor) of the substrate 20 with a single magnetic film 10 according to this disclosure. For example, since the movement control of the substrate 20 by energizing the coil and the feedback detection of the position of the substrate 20 by the Hall element can be performed integrally, it is advantageous for miniaturizing and simplifying the entire device.

[0038] 2.3. Fixing the Position of the Substrate The magnetic flux generating member 1 of this disclosure, with its first region 11 and second region 12 magnetized in different directions, can also be used to restrain and fix the substrate 20 in a predetermined position. For example, the interaction between the magnetic flux generated by the magnetic film 10 on the substrate 20 side and a magnetic material or coil provided on the device side makes it possible to attract and hold the substrate 20 in a specific position. Specifically, if a magnetic field is applied that causes the substrate 20 to adhere to a surface perpendicular to the magnetic flux emanating from the magnetic film 10 (for example, the inner wall surface of the device housing), the substrate 20 will be locked (stationary) in that position. In this state, even if an external force is applied, the substrate 20 will not easily shift from its predetermined position, thus serving a fixing function. The position fixing function is useful when it is desired to keep the substrate 20 (movable part) stationary in a fixed position after actuator drive, or when it is desired to prevent positional displacement by applying a holding force even when the device is not energized.

[0039] 2.4. Attraction and Repulsion of Other Components Furthermore, the magnetic flux generated from the magnetic flux generating member 1 of this disclosure can also be used to exert an attractive or repulsive effect on an object (movable body) separate from the base material 20. This function allows for the indirect movement or holding of other external objects without moving the magnetic flux generating member 1 itself. For example, if an object made of a magnetic material such as another small magnet or an iron piece is placed in the magnetic field generated by the magnetic film 10 of this disclosure, it is possible to attract and pull that object towards the magnetic flux, or conversely, push it away with the repulsive force between like poles. The object to be moved (moving body) can be any material that has the property of being attracted to or repelled by magnetic flux, and may be a permanent magnet itself, a ferromagnetic material such as iron, or a magnetic fluid or magnetic particles.

[0040] Furthermore, by placing an energized conductor (such as a coil) in the magnetic flux generated by the magnetic film 10 of this disclosure, the conductor can be pushed aside by the force of electromagnetic induction. For example, the repulsive force generated by instantaneous energization of the coil can be used to move the coil itself at high speed as part of a mechanism. Similarly, by controlling charged particles (such as plasma or charged aerosols) in the magnetic flux, it can be used for contactless transport and trajectory control. In this way, the magnetic flux generating member 1 of this disclosure can function as an actuator means for directly manipulating and controlling other objects in its surroundings.

[0041] As described above regarding the multifaceted effects of the magnetic flux generated by the magnetic flux generating member 1 of this disclosure, the magnetic film 10 of this disclosure can perform two or more functions with a single unit. Therefore, it becomes possible to realize complex functions (for example, "driving + detection" or "multi-axis driving + fixed holding," etc.) that were conventionally achieved by individually arranging multiple magnets or sensors, with a simpler configuration. By using the magnetic flux generating member 1 of this disclosure, for example, in motor and actuator devices, the driving, positioning, and braking functions can be integrated, and in sensor devices, it becomes easy to increase the number of detection axes and perform simultaneous measurement. For example, in applications to lens actuators for small cameras, it is possible to realize a configuration in which a single magnetic film 10 serves both focus driving (position control) and image stabilization detection (sensor), greatly contributing to the miniaturization and thinning of the device. As described above, the magnetic flux generating member 1 of this disclosure allows a single member to perform multiple roles, and it is possible to simultaneously reduce the number of parts and improve the performance of the entire device.

[0042] 3. Sensor Using a Magnetic Film The sensor of this disclosure comprises the magnetic flux generating member 1 and a magnetic sensor 124 positioned to be magnetically interactable with the magnetic film 10. Specifically, when the magnetic film is subjected to an external magnetic field and undergoes a change in position or angle, its magnetic flux distribution changes the amount of magnetic flux passing through the magnetic sensor. This causes an induced electromotive force and inductance change in the magnetic sensor, and by detecting this electrical signal, the position and displacement of the magnetic flux generating member can be measured non-contact. For example, a method can be employed in which an alternating current is applied to the magnetic sensor to detect the change in impedance, or a method can be employed in which the magnetic sensor is arranged as a passive element to detect the induced voltage accompanying the movement of the magnetic film.

[0043] Furthermore, if the magnetic film is magnetized with multiple poles, the magnetic sensor can sequentially detect multiple magnetic poles in response to the movement and rotation of the substrate, enabling measurement of not only linear displacement but also rotation angle and velocity. Thus, the sensor disclosed herein can realize multi-degree-of-freedom detection functions in a compact configuration, going beyond simple position detection.

[0044] 4. Actuator Using a Magnetic Film The actuator of this disclosure comprises a fixed part and a movable part, one of the fixed part and the movable part having the magnetic flux generating member, and the other fixed part and the movable part having a coil positioned to be magnetically interactable with the magnetic film. Here, the magnetic flux generating member 1 may be formed directly on the surface of the fixed part or the movable part. This makes it possible to provide a small, lightweight, highly efficient and reliable actuator while eliminating constraints on assembly and processing.

[0045] In the following, we will describe a configuration in which the movable part has a lens and the fixed part has an image sensor, and a configuration in which the fixed part has a lens and the movable part has an image sensor.

[0046] 4.1. Figure 2A shows a cross-sectional view illustrating one embodiment of the actuator for a miniature camera according to the present disclosure, with a lens on the movable part side and an image sensor on the fixed part side. As shown in Figure 2A, in the actuator for a miniature camera 100, the movable part 110 is equipped with a lens unit 111, and the fixed part 120 is equipped with an image sensor 121, with the image sensor 121 and the lens unit 111 arranged on the same optical axis. The movable part 110 is equipped with a base material 20 made of a magnetic material, and a magnetic film 10 is directly formed on its outer circumferential surface. A drive coil 122 is arranged on the fixed part 120 at a position opposite to the movable part 110, and each drive coil 122 is arranged corresponding to the direction of the magnetic flux generated by the magnetic film 10.

[0047] The magnetic film 10 is a thin-film magnet formed on the surface of the substrate 20, and is magnetized in its thickness direction (a direction substantially perpendicular to the surface of the substrate 20). In Figure 2A, the magnetization direction is indicated by an arrow. In Figure 2A, the tip of the arrow points to the north pole. This magnetic film 10 has a magnetic flux generation function in the X, Y, and Z axes, and drives the movable part 110 (lens unit 111) in the X / Y and Z directions through interaction (attraction and repulsion) with the magnetic field generated by energizing the opposing coil. This optimizes the relative positional relationship between the lens unit 111 and the fixed image sensor 121, enabling autofocus drive in the Z direction and image stabilization in the X / Y directions. The movable part 110 is supported by the fixed part 120 by an elastic body 123 such as a spring, and a passive positional restoring force may be applied so that the optical axis is always aligned.

[0048] In this disclosure, since the magnetic film 10 is thin, lightweight, and formed without an adhesive layer, the magnet, which conventionally had to be placed on the fixed part 120 side, can be placed on the movable part 110 side. This allows the drive coil 122, which generates heat, to be placed on the fixed part 120 side, and the fixed part 120 can act as a heat sink to dissipate the heat from the coil, making it possible to pass a larger current and drive at high speed. Furthermore, from this viewpoint, the fixed part 120 is preferably made of a material with good thermal conductivity, such as resin or metal.

[0049] Furthermore, as shown in Figure 2B, the magnetic film 10 may be magnetized in such a way that multiple different polarities (N poles and S poles) appear (hereinafter also referred to as "multi-pole magnetization"). By creating a structure in the magnetic film 10 where multiple N poles and S poles exist through multi-pole magnetization, it is possible to design a complex magnetic circuit or create a magnetic field distribution tailored to a specific application. By creating a structure in which N poles and S poles are adjacent in the X / Y / Z plane through multi-pole magnetization, the magnetoresistance of the magnetic circuit around the magnet can be reduced, and the magnetic path becomes relatively closed, thereby reducing the leakage magnetic field of the actuator. In addition, since the magnetic flux is concentrated in the coil / magnetic sensor 124, the driving force of the actuator can be increased. When a magnetic sensor 124 is provided, the position detection accuracy is improved, enabling more precise feedback control.

[0050] Figure 2C shows an example of the laminated structure of the base material 20 and the magnetic film 10 of the movable part 110. Typically, the magnetic film 10 may be formed directly on the movable frame of the soft magnetic material.

[0051] Furthermore, in Modification 1, the magnetic flux generating member 1, which has a movable frame 112 separate from the soft magnetic material (yoke) and a magnetic film 10 directly formed on the surface of the soft magnetic material (yoke), may be bonded to the movable frame 112 via an adhesive 113 or the like. Modification 1 is useful in that it can produce the same effects as the typical example and other modifications in that it can form a magnetic circuit with the multi-pole magnetization configuration described above, but because it uses a bonding method via an adhesive, the typical example in which the magnetic film is directly formed on the substrate, and Modifications 2 and 3 described later, are more preferable from the viewpoint of thinning and simplifying the process. Similarly, in Modification 2, the magnetic flux generating member 1 may be directly bonded to the movable frame 112.

[0052] Furthermore, in Modification 3, the yoke element may have a concentration gradient in the magnetic film 10. Also, in Modification 3, the soft magnetic material (yoke) and the movable frame 112 are shown as separate components, but instead, as in the typical example, the soft magnetic material (yoke) and the movable frame may be the same, and the yoke element may have a concentration gradient.

[0053] In this disclosure, a magnetic sensor 124 (e.g., a Hall element) for detecting the magnetic flux generated by the magnetic film 10 may be provided on the fixed part 120, thereby enabling non-contact detection of the position and orientation of the movable part 110. When a magnetic detector such as a Hall element is placed opposite the magnetic film 10, the output of the detector changes according to the magnetic field strength from the magnetic film 10. By calculating the relative distance between the movable part 110 equipped with the magnetic film 10 and the magnetic detector from this output change, it is possible to detect the position of the lens unit 111 (movable part 110) with high precision.

[0054] For example, the displacement in the Z-axis direction (optical axis direction) can be calculated from the magnetic field strength, allowing the distance (focus position) between the lens and the image sensor 121 to be determined in real time. Furthermore, by arranging multiple magnetic sensors 124 in the X and Y axis directions and detecting changes in magnetic flux in each direction, the two-dimensional displacement of the movable part 110 can be measured.

[0055] The position detection signal obtained by the magnetic sensor 124 is fed back to the control circuit, which adjusts the current to each drive coil 122 according to the deviation from the target position to control the position of the movable part 110. This constitutes a feedback control system that positions the lens to the desired focus position or correction position while maintaining high precision alignment between the lens optical axis and the center of the image sensor 121 (optical axis alignment). For example, in response to a small lateral displacement of the lens unit 111 detected during image stabilization, the control circuit sends a correction current to the coil, moving the lens unit 111 in the opposite direction to cancel out the optical axis misalignment. The combination of detection by the magnetic sensor 124 and magnetic flux generation by the magnetic film 10 improves the positioning accuracy and responsiveness of the movable part 110, enabling precise feedback control.

[0056] Furthermore, the sensor function of the magnetic film 10 may be not only for position detection but also for angle detection (tilt detection). For example, if the movable part 110 equipped with the magnetic film 10 rotates (tilts) slightly around a certain axis, its magnetic flux distribution also changes accordingly. In this disclosure, for example, a plurality of magnetic sensors 124 arranged on the fixed part 120 may detect the difference in magnetic field strength in response to the tilt of the movable part 110 around the X or Y axis. This makes it possible to calculate the tilt angle of the lens unit 111 and reflect it in the correction control. That is, the magnetic film 10 can generate magnetic flux for detecting parallel movement and magnetic flux for detecting rotational movement in cooperation with the magnetic sensors 124. By using this angle detection function in combination, even slight tilts of the optical axis can be detected and compensated for, enabling more advanced image stabilization and correction.

[0057] As described above, in this configuration, the magnetic film 10 of the movable part 110 functions not only as a driving magnet but also as a sensor for detecting position and attitude. This reduces the number of parts and simplifies the structure, and has the advantage of eliminating the position sensor that was previously mounted separately. Since the magnetic film 10 is directly formed on the movable part 110, it is lighter than conventional magnets and also contributes to reducing the inertia of the movable part 110. As a result, the high-speed response of the actuator is improved, and heat dissipation when a large current is applied is efficiently performed via the fixed part 120. With the above configuration, a compact camera module that can control the lens position at high speed and with high precision has been realized.

[0058] Next, Figures 2D to 2H show other drawings illustrating actuators for small cameras.

[0059] Figure 2D shows a perspective view of the small camera actuator shown in Figure 2A. As shown in Figure 2D, the movable part 110 is housed within the fixed part 120, and the movable part 110 is driven within the fixed part 120 by a magnetic flux generating member 1 installed on the movable part 110 and a drive coil 122 installed on the fixed part 120. One side has an opening through which a lens is visible, and the other side (bottom side) has an image sensor 121.

[0060] Figure 2E is a perspective view of the movable part 110 in the actuator of Figure 2A. The movable part 110 may have a frame made of a magnetic flux generating member 1 and a lens unit 111 fitted inside it. The lens unit 111 is fixed inside the movable part 110 and the lens optical system is driven by moving together with the movable part 110 in the X, Y, and Z directions.

[0061] Figure 2F is a perspective view of the movable part 110 in the actuator of Figure 2A, as seen from the image sensor 121 side, and shows the movable part 110 as observed from the opposite side to Figure 2E. The frame formed by the magnetic flux generating member 1 may be positioned to surround the rear surface of the lens unit 111.

[0062] Figure 2G is a perspective view of the fixed part 120 of the actuator in Figure 2A, before the movable part 110 is installed, as seen from the lens unit 111 side. The fixed part 120 is a frame that encloses the actuator, and various components such as a drive coil 122, an image sensor 121, and a magnetic sensor 124 may be mounted inside it. Spaces may be provided on the inner wall surface of the fixed part 120 for mounting the drive coils 122 in the X, Y, and Z directions, and these are arranged to surround the lens opening.

[0063] Figure 2H is a perspective view showing the interior of the fixed part 120, with a portion of its wall removed to clearly illustrate the internal structure of the fixed part 120 shown in Figure 2G. This figure shows the positions of each drive coil 122 (for example, coils for the X, Y, and Z directions) arranged within the fixed part 120, as well as the installation locations of the image sensor 121 and the magnetic sensor 124. The image sensor 121 is mounted at a position corresponding to the lens unit 111, and coils are arranged on the inner wall of the fixed part 120 around it. The magnetic sensor 124 is provided to detect the position of the movable part 110, and is positioned to detect, for example, the magnetic field of the magnetic film 10 attached to the movable part 110.

[0064] As a modified example, Figure 3A shows an embodiment in which a magnetic film 10 is formed on the inner surface of the fixed part 120 instead of the movable part 110. When the fixed part 120 itself functions as a soft magnetic yoke, the magnetic flux generated from the magnetic film 10 passes through the fixed part 120, forming a closed magnetic circuit. This suppresses leakage of the magnetic field to the outside of the actuator, and has the effect of reducing magnetic interference with surrounding electronic equipment.

[0065] Figure 3B is a cross-sectional view showing one embodiment of the actuator configuration in Figure 3A where the magnetic film 10 of the fixed part 120 is multi-pole magnetized. By magnetizing the magnetic film 10 formed on the inner surface of the fixed part 120 so that multiple regions alternately become N poles and S poles (multi-pole magnetization), a large number of magnetic poles are formed on the magnetic film 10. Figure 3B conceptually shows the resulting magnetic pole pattern on the magnetic film 10. In the multi-pole magnetized magnetic film 10, as in the case of Figure 2B, the N poles and S poles are adjacent in the plane, making it easier for the flow of magnetic flux to be locally closed, and improving the overall magnetic circuit efficiency.

[0066] This multi-pole magnetization suppresses magnetic flux leakage and reduces the influence of the magnetic field around the actuator. In addition, it makes it easier to concentrate the magnetic flux on the coil and magnetic sensor 124, thereby improving the drive performance and control accuracy of the device. Furthermore, in the configuration shown in Figure 3B, the presence of multiple N and S poles in the magnetic film 10 of the fixed part 120 makes it possible to precisely design the magnetic flux distribution corresponding to each drive coil 122, for example, and to create a magnetic field environment optimized for a specific drive shaft.

[0067] 4.2. Diagram 4A shows a cross-sectional view illustrating another embodiment of the actuator for a miniature camera of the present disclosure, in which the actuator has a lens on the fixed part side and an image sensor on the movable part side. Diagram 4A is a cross-sectional view showing an embodiment in which the arrangement relationship between the lens unit 221 and the image sensor 211 is reversed as a modification of the actuator configuration shown in Figure 2A. In the actuator for a miniature camera 200, the movable part 210 is equipped with the image sensor 211, and the fixed part 220 is equipped with the lens unit 221, and the image sensor 211 and the lens unit 221 are arranged on the same optical axis. The movable part 210 is equipped with a base material 20 made of a magnetic material, and a magnetic film 10 is directly formed on its outer circumferential surface. The movable part 210 and the fixed part 220 are connected by an elastic body 223, and a drive coil 222 is arranged on the fixed part 220 at a position facing the magnetic film 10 of the movable part 210, and each drive coil is arranged corresponding to the direction of the magnetic flux generated by the magnetic film 10.

[0068] Next, Figures 4B to 4D show other drawings illustrating actuators for small cameras.

[0069] Figure 4B shows a perspective view of the small camera actuator shown in Figure 4A, below the lens unit 221. As shown in Figure 4B, the movable part 210 is housed within the fixed part 220, and the movable part 210 is driven within the fixed part 220 by a magnetic flux generating member 1 installed on the movable part 210 and a drive coil 222 installed on the fixed part 220.

[0070] Figure 4C is a perspective view of the movable part 210 in the actuator of Figure 4A. The movable part 210 may have a frame made of a magnetic flux generating member 1 and an image sensor 211 positioned inside it. The image sensor 211 is fixed inside the movable part 210 and drives the lens optical system by moving together with the movable part 210 in the X, Y, and Z directions.

[0071] Figure 4D is a perspective view of the fixed part 220 of the actuator in Figure 4A, before the movable part 210 is installed, as seen from the lens unit 221 side. The fixed part 220 is a frame that encloses the actuator, and various components such as drive coils 222 and magnetic sensors 224 may be mounted inside it. Spaces for mounting drive coils 222 in the X, Y, and Z directions may be provided on the inner wall surface of the fixed part 220, and these are arranged to surround the movable part 210.

[0072] In this configuration, when current flows through the drive coil, its magnetic flux interacts with the magnetic flux generated from the magnetic film 10 (permanent magnet layer) on the inner surface of the fixed part 220, becoming the driving force for the movable part 210 in the X, Y, and Z directions. That is, parallel movement for image stabilization in the X and Y axes and movement for focus adjustment in the Z axis direction are possible, and the relative position of the image sensor 211 with respect to the fixed lens can be adjusted by moving the movable part 210. Since the lens unit 221 itself is held by the fixed part 220 and the optical system is stable, the positional relationship between the sensor surface and the lens optical axis is optimized by controlling the position of the movable part 210, thereby performing focusing and image stabilization.

[0073] The detection mechanism using the magnetic film 10 and magnetic sensor 224 in this configuration is basically the same as that described above. In this configuration, the image sensor 211 shifts laterally (X / Y direction) relative to the optical axis to perform image stabilization. Therefore, a Hall IC capable of two-axis detection may be used as the magnetic sensor 224, or multiple single-axis magnetic sensors may be arranged to independently detect positional displacement in the X-axis and Y-axis directions. The detection signal is fed back to the control system, and feedback control is realized to keep the position of the movable part 210 (image sensor 211) constantly following the target by controlling the coil current according to the deviation from a predetermined target position. For example, if a tendency for the sensor to deviate laterally from the lens optical axis is detected due to device vibration, the control system performs a corrective operation and drives the movable part 210 in the reverse direction to maintain optical axis alignment.

[0074] As a variation, it is also possible to adopt a configuration in which a magnetic film 10 is provided on the inner surface of the fixed part 220 and a drive coil is arranged on the outer circumference of the movable part 210 (see Figure 5). In either case, the principle of detecting the position and orientation of the movable part 210 from the change in the relative positional relationship between the magnetic film 10 and the magnetic sensor 224 is the same, and the fact that the magnetic film 10 functions as a magnetic flux source for the sensor remains unchanged.

[0075] 5. Manufacturing Method 5.1. Formation of Magnetic Film on Movable Parts The method for forming a magnetic film 10 on movable parts and manufacturing an actuator will be described below with reference to Figures 6A to 6D.

[0076] First, a base material 20 is prepared as the base member. The base material 20 is not particularly limited, but in order to form a magnetic film 10 on the surface of the base material 20, at least the surface of the base material 20 may have the same transition metal element as the transition metal element contained in the main magnetic layer. Examples of materials for the base material 20 include Co, Fe, Ni, Mo, Ta, Nb, FeCo, CoCr, CoCrMo, etc. For example, if the transition metal element contained in the main magnetic layer is Co or Fe, the surface of the base material 20 may have a Co layer or an Fe layer. Alternatively, the base material 20 may be a Co base material or an Fe base material.

[0077] When a Co substrate is used as the base material 20, it is preferably a metal Co plate or a metal Co block, and the purity of Co in the Co substrate may be 99% by mass or more, or 99.998% by mass or more. Another base material 20 may be placed beneath the Co substrate. The thickness of the Co substrate is not particularly limited and can be appropriately selected depending on the application, but for example it can be 0.01 to 2 mm.

[0078] Next, a method for manufacturing a magnetic film 10 on the surface of the substrate 20 will be described in detail. As an example, the case in which a Co substrate is used as the substrate 20 will be described. First, as shown in Figure 6A, a substrate 20 consisting of Co blocks is prepared.

[0079] The surface of the substrate 20 is preferably roughened. For example, the arithmetic mean surface roughness Ra (e.g., JIS B 0601) of the surface of the substrate 20 is preferably 0.5 μm or more, and more preferably 5.1 μm or more. There is no particular upper limit to the arithmetic mean surface roughness Ra of the substrate 20, but it may be, for example, 50 μm or less, or 29 μm or less. Surface roughness can be measured by known methods. Furthermore, the surface roughness of the substrate 20 can be controlled by known methods, such as sanding, sandblasting, barrel polishing, electrolytic polishing, and surface processing methods such as forming desired patterns (checkerboard patterns, etc.) by combining photolithography and etching (wet etching, dry etching, microblasting, etc.). In this case, when processing with sandpaper, it is preferable to perform the polishing in a random direction.

[0080] Next, as shown in Figure 6B, SmCo is applied to the surface of the substrate 20. ２ A magnetic film 10, such as a thin film, is formed. The magnetic film 10 is preferably manufactured by, for example, a molten salt immersion method or a method that applies the molten salt immersion method. Hereinafter, the magnetic film 10 will be SmCo ２ Let's explain an example of membrane formation.

[0081] First, a base material 20 and a reaction solution containing an Sm source and a molten salt are prepared. When preparing the reaction solution, a predetermined inorganic salt is first dehydrated by drying. Examples of inorganic salts include KCl (potassium chloride), LiCl (lithium chloride), and NaCl (sodium chloride). One type of inorganic salt may be used, or two or more types of inorganic salts may be used in combination. The dehydrated inorganic salt is heated to a predetermined temperature to melt it (molten salt). The temperature at which the inorganic salt is melted can be appropriately determined depending on the type of inorganic salt used, but it is preferably 400°C or higher, 500°C or higher, or 600°C or higher.

[0082] An Sm source is added to the molten salt (molten inorganic salt) to obtain a reaction solution. Examples of Sm sources include metallic Sm and Sm alloys, and one type of Sm source may be used, or two or more types of Sm sources may be used. If the total number of moles of Sm source and inorganic salt in the reaction solution is 100 mol%, the proportion of Sm source in the reaction solution is preferably, for example, 0.2 mol% or more and 6 mol% or less.

[0083] Next, the reaction solution is brought into contact with the surface of the substrate 20, and the Sm source in the molten salt is reacted and diffused onto the surface of the substrate 20, thereby forming a magnetic film containing Sm on the surface of the substrate 20. This step will be referred to as the reaction diffusion step.

[0084] In the reaction-diffusion step, the Co substrate (substrate 20) is immersed in the reaction solution at a predetermined temperature for a predetermined time to form a magnetic coating containing Sm on both sides of the substrate 20. However, if the substrate 20 is immersed in the reaction solution as is, a magnetic coating containing Sm will form even in areas where a magnetic coating is not needed, resulting in a decrease in yield. Therefore, areas where a magnetic coating is not needed may be covered with an inert film to suppress reaction-diffusion.

[0085] For example, it is preferable to form a mask of a high-melting-point material in areas where it is not needed. Examples of high-melting-point materials include W, Ta, Nb, Mo, or alloys containing at least one of these elements. The mask of the high-melting-point material can be formed, for example, by vapor deposition. After forming a mask of the high-melting-point material on the outer surface and end surface, the substrate 20 is immersed in the reaction solution, allowing the Sm source to react and diffuse only in the necessary areas of the substrate 20, thereby forming a magnetic coating containing Sm.

[0086] In the reaction-diffusion step, the temperature of the reaction solution is maintained at a temperature that allows the inorganic salt to remain molten. From the viewpoint of efficiently forming a magnetic film, the temperature of the reaction solution is preferably 500°C to 900°C, and 650°C to 800°C. The reaction time can be appropriately set according to the reaction temperature and the proportion of Sm source in the reaction solution so that a magnetic film of the desired thickness can be formed. For example, the reaction time may be 1 hour to 60 hours.

[0087] In this disclosure, during the reaction time of the reaction-diffusion step, the concentration of Sm (an example of a rare earth element) in the reaction solution is not constant between the start and end of the reaction. Instead, the concentration of Sm at the end of the reaction is controlled to be at least 0.5 mol / L higher than at the start of the reaction. Specifically, the concentration of Sm at the start of the reaction may be 0.5 mol / L, and the concentration of Sm at the end may be 1.5 mol / L. For example, the concentration of Sm in the reaction solution is increased by gradually adding an Sm source to the reaction solution, thereby adjusting the concentration distribution of the transition metal element T in the magnetic film 10. The method of adding the Sm source may be continuous, intermittent, or all at once.

[0088] The magnetic coating formed on the surface of the substrate 20 in the reaction diffusion process is Sm ２ Co １７ Layer and SmCo ５ It is a precursor of the layer. Specifically, the magnetic coating after the reaction diffusion process is Sm ２ Co ７ SmCo ３ SmCo ２ Sm ５ Co ２ Sm ３It is preferable that it contains Co and Sm as the main phases, and SmCo ２ It is particularly preferable to include as the main phase. SmCo ２ MgCu ２ It is an alloy of Sm and Co having a crystal structure of type . The main phase is SmCo ２ MgCu ２ If it has a crystal structure of the type, SmCo ２ The ratio of Sm atoms to Co atoms in this mixture may deviate slightly from the stoichiometric ratio. For example, when additive elements are added to improve magnetic properties, the ratio of Sm atoms to Co atoms may deviate slightly from the stoichiometric ratio.

[0089] The magnetic coating consists of a main phase as well as SmCo ２ It may also contain different phases such as an Sm-rich phase with a higher Sm ratio, and grain boundary phases. The SmCo2 content in the magnetic coating is preferably 50 wt% or more, 70 wt% or more, and 90 wt% or more.

[0090] Furthermore, after the reaction diffusion step, the substrate 20 on which the magnetic film has been formed may be washed with an organic solvent such as ethanol or pure water.

[0091] Next, SmCo ２ A substrate 20 on which a magnetic coating containing is formed is heated at a predetermined temperature for a predetermined time (heating step). In this heating step, SmCo ２ The reaction between the Co on the surface of the substrate 20 proceeds further, and the Co on the surface of the substrate 20 and SmCo ２ From a magnetic coating consisting of layers, Sm ２ Co １７ Submagnetic layer consisting of layers and SmCo ５ A main magnetic layer consisting of layers may be formed. Alternatively, a secondary magnetic layer may be formed on the surface of the main magnetic layer.

[0092] The heating rate in the heating process is not particularly limited, but is preferably, for example, 1°C / min or more and 20°C / min or less. The holding temperature (target temperature) is preferably 800°C or more and 1200°C or less, 850°C or more and 1150°C or less, and 900°C or more and 1100°C or less. The holding time at the above holding temperature is preferably, for example, 2 hours or more and 48 hours or less. Furthermore, the cooling rate during cooling after heating is preferably 5°C / min or more, 10°C / min or more, and 20°C / min or more.

[0093] The atmosphere during the heating process is not particularly restricted, but SmCo ５ From the viewpoint of suppressing oxidation of the layer, an inert gas atmosphere is preferred. Examples of inert gases include Ar gas and N ２ Using gas or similar methods would suffice.

[0094] In this disclosure, after the heating step, the temperature may be reduced to a predetermined temperature and then maintained at that predetermined temperature for a predetermined time (low-temperature annealing step). This low-temperature annealing step converts the Co of the substrate 20 to SmCo. ５ Co elements diffuse into the grain boundaries through the crystal grain boundaries, forming SmCo. ５ The two-particle grain boundaries between crystalline particles may be modulated. In other words, it is thought that an amorphous phase richer in transition metals (Co) than the main phase crystalline particles, or a mixed phase of amorphous and microcrystalline phases, is more likely to form at the two-particle grain boundaries.

[0095] The holding temperature in the low-temperature annealing process is preferably 550°C to 700°C, and 550°C to 600°C. The holding time in the low-temperature annealing process is preferably, for example, 2 hours to 8 hours. In particular, in annealing at 600°C or below, SmCo ５ It is believed that without the coarsening of the crystal grains of the main phase or decomposition of the main phase, the element (Co) of the substrate 20 diffuses through the two-particle grain boundary, and as a result, amorphous two-particle grain boundaries with a thickness of several nanometers are more easily formed. Note that two-particle grain boundaries are formed even without low-temperature annealing.

[0096] The multilayer magnetic film 10 can be manufactured through the above-described process (reaction diffusion process, heating process, and low-temperature annealing process). In the magnetic film 10, Sm ２ Co １７ Layer and SmCo ５ The layers are formed in that order on the surface of the substrate 20, and a multilayer structure is obtained. If a mask of high-melting-point material is formed on the surface of the substrate 20, the mask of high-melting-point material may be removed after the heating step, or the mask of high-melting-point material may be left in place.

[0097] The method for manufacturing the magnetic film 10 described above can be applied not only to a flat substrate 20, but also, for example, to forming the magnetic film 10 on the surface of a base member having various curved surfaces. In addition, it can also be applied to forming the magnetic film 10 on the inner surface of a cylindrical base member.

[0098] As described above, after forming a magnetic film 10 on the front surface of the cobalt block, the magnetic film 10 can be directly formed on the outer surface of the movable part 110 by cutting it into an arbitrary shape using an end mill or the like, as shown in Figure 6C. Furthermore, the magnetic film 10 formed in this way is magnetized such that the direction of magnetic flux generation from the coil is substantially perpendicular to the magnetic film 10. When performing multi-pole magnetization, it is sufficient to combine it with general pulse multi-pole magnetization.

[0099] Next, the lens unit is fitted inside the movable part 110 formed as described above to form the movable part (Figure 6D). The drive coils, image sensor, and magnetic sensor are then installed within the fixed part 120 to form the fixed part (see Figures 2G and 2H). Finally, the movable part is combined with the fixed part to create the actuator. In this case, the movable part may be connected to the fixed part with an elastic body such as a spring.

[0100] 5.2. Another embodiment for forming a magnetic film on a fixed part: A method for forming a magnetic film 10 on a fixed part and manufacturing an actuator will be described below with reference to Figures 7A to 7E.

[0101] First, a cobalt block is prepared as the base material 20 (Figure 7A), and a base material that does not contain transition metal elements is formed on the surface of the base material 20 by sputtering or the like (Figure 7B). Then, by cutting it into an arbitrary shape with an end mill or the like, a fixing part 120 having a cobalt film on the inner surface of the base material can be obtained (Figure 7C). This cobalt film becomes the base material 20.

[0102] Next, using the molten salt immersion method or the above-described method applying the molten salt immersion method, SmCo is applied to the cobalt film on the inner surface of the fixed part 120. ２ A magnetic film 10, such as a thin film, is formed (Figure 7D). Then, a fixing portion 120 may be formed by cutting it into an arbitrary shape using an end mill or the like (Figure 7E).

[0103] By installing the drive coils, image sensor, and magnetic sensor on the fixed part 120 formed in this manner, a fixed part can be created. Then, as described above, an actuator can be manufactured by combining the movable part with the fixed part. In this case, the movable part may be connected to the fixed part with an elastic body such as a spring.

[0104] 1...Magnetic flux generating member, 10...Magnetic film, 11...First region, 12...Second region, 20...Base material, 21...First surface, 22...Second surface, 100...Actuator for miniature camera, 110...Movable part, 111...Lens unit, 120...Fixed part, 121...Image sensor, 122...Drive coil, 123...Elastic body, 124...Magnetic sensor, 200...Actuator for miniature camera, 210...Movable part, 211...Image sensor, 220...Fixed part, 221...Lens unit, 222...Drive coil, 223...Elastic body, 224...Magnetic sensor

Claims

1. A magnetic flux generating member comprising a base material and a magnetic film formed on the surface of the base material, wherein one of the magnetic films has a first region and a second region magnetized in different directions.

2. The magnetic flux generating member according to claim 1, wherein the first region is magnetized such that it moves the substrate relatively in a first direction when subjected to an external magnetic field, and the second region is magnetized such that it moves the substrate relatively in a second direction different from the first direction when subjected to an external magnetic field.

3. The magnetic flux generating member according to claim 1, wherein the substrate has a first surface, a second surface, and a corner portion connecting the first surface and the second surface, and one magnetic film continuously covers the first surface, the second surface and the corner portion, the first region covers the first surface, and the second region covers the second surface.

4. The magnetic flux generating member according to claim 1, wherein one of the magnetic films has a first region and a second region that are magnetized in different directions within the same plane.

5. The magnetic flux generating member according to claim 1, wherein the magnetic film is magnetized in a direction substantially perpendicular to the substrate surface.

6. The magnetic flux generated from one of the magnetic films has two or more functions selected from the group consisting of: a function to move the substrate along an arbitrary axial direction; a function to rotate the substrate about an arbitrary axis; a function to detect the axial motion of the substrate; a function to detect the rotational motion of the substrate; a function to fix the substrate in a predetermined position; a function to attract a moving body separate from the substrate; and a function to repel a moving body separate from the substrate.

7. The magnetic flux generating member according to claim 1, wherein the thickness of the magnetic film is 10 to 300 μm.

8. The magnetic flux generating member according to claim 1, wherein the base material is a magnetic or non-magnetic material.

9. The magnetic flux generating member according to claim 1, wherein the magnetic film comprises a rare earth element and a transition metal element, the rare earth element comprises Sm and / or Nd, and the transition metal element comprises Co and / or Fe.

10. The magnetic flux generating member according to claim 1, wherein the magnetic film comprises a rare earth element and a transition metal element, and the magnetic film has a concentration gradient of the transition metal element.

11. When the rare earth element is represented as R and the transition metal element as T, the magnetic film is RT ５ , R ２ T １７ , RT １２ , R ２ T １７ N ３ A magnetic flux generating member according to claim 10, having any of the above.

12. A sensor comprising a magnetic flux generating member according to any one of claims 1 to 11, and at least one magnetic sensor or coil disposed in a position where it can magnetically interact with the magnetic film.

13. An actuator comprising a fixed part and a movable part, wherein one of the fixed part and the movable part has a magnetic flux generating member according to any one of claims 1 to 11, and the other of the fixed part and the movable part has a coil positioned to be magnetically interactable with the magnetic film.

14. The actuator according to claim 13, wherein the magnetic flux generating member is formed directly on the surface of the fixed portion or the movable portion.

15. The actuator according to claim 13, wherein the movable part has a lens unit, the fixed part has an image sensor, and the image sensor and the lens unit are arranged on the same optical axis.

16. The actuator according to claim 13, wherein the fixed portion has a lens unit, the movable portion has an image sensor, and the image sensor and the lens unit are arranged on the same optical axis.

Images