Voice coil motor

Abstract

This improves the overall thrust of the voice coil motor while suppressing an increase in horizontal size. [Solution] The first magnet holder 20A has a first magnet 21b of first polarity and a second magnet 22b of second polarity, facing the first coil holder 60. The second magnet holder 30A has a third magnet 31b of second polarity and a fourth magnet 32b of first polarity on one side, facing the first coil holder 60, and a fifth magnet 35b of first polarity and a sixth magnet 36b of second polarity on the other side, facing the second coil holder 70. The third magnet holder 40A has a seventh magnet 41b of second polarity and an eighth magnet 42b of first polarity, facing the second coil holder 70. The first magnet holder 20A, the second magnet holder 30A, and the first coil holder 60 allow the magnet unit 10 to move in the x-axis direction, while the second magnet holder 30A, the third magnet holder 40A, and the second coil holder 70 allow the magnet unit 10 to move in the y-axis direction.

Description

【Technical Field】 【0001】 The present disclosure relates to the structure of a voice coil motor (VCM). 【Background Art】 【0002】 As a prior art related to a voice coil motor, there is a position detection device that is applied to an optical image shake correction device having a VCM type drive mechanism, and that can secure high position detection accuracy while adopting a magnetic detection type form and contributes to the miniaturization of the device. (See, for example, Patent Document 1). FIG. 18 is an external perspective view of an image shake correction device to which a position detection device of an embodiment of the prior art is applied. FIG. 19 is an external perspective view showing a fixed portion of the image shake correction device of FIG. 18. FIG. 20 is an external perspective view showing the state of a movable portion on which an imaging unit is mounted in the image shake correction device of FIG. 18 as seen from the direction of arrow [5] (the back side) in FIG. 18. 【0003】 A fixed member 41 in which one of a conventional magnet 43 or coil 53 is arranged, a movable frame 52 in which the other of the magnet or coil and an optical element 32 are arranged, and a movable member 51 driven by a VCM drive unit including a magnet and a coil in a direction perpendicular to the direction along the optical axis O (not shown) of the optical element with respect to the fixed member, and a magnetic detection member 36 (not shown) that is arranged in a member in which the coil is arranged in either the movable member or the fixed member and detects a change in the magnetic flux density of the magnet when the movable member is driven. The magnetic detection member is arranged at a position where the magnetic flux density of the coil does not affect the change in the magnetic flux density by the magnet when an electric current is passed through the coil in a plane perpendicular to the direction along the optical axis. (Patent Document 1, [Summary]). 【0004】 The movable part 51 is configured to have a movable frame 52 on which a plurality of drive coils 53 of the VCM drive unit and the imaging unit 31 (optical element) are arranged. The movable part 51 is a movable member that is driven by the VCM drive unit, which includes a drive magnet 43 and drive coils 53, to move the movable frame 52 in a direction perpendicular to the direction along the optical axis O of the imaging optical system (optical element) relative to the fixed part 41 (fixed member). The movable part 51 is configured to be stacked parallel to the fixed part 41 and to be movable in a direction parallel to the plane (XY plane) perpendicular to the optical axis O relative to the fixed part 41 (Patent Document 1,

[0053] -

[0054] ). [Prior art documents] [Patent Documents] 【0005】 [Patent Document 1] Japanese Patent Publication No. 2018-194587 [Overview of the Initiative] [Problems that the invention aims to solve] 【0006】 When controlling a voice coil motor in a two-dimensional direction, for example, as shown in Patent Document 1, a method is known in which four pairs of magnets are arranged on the same surface of the magnet holding portion, and coils corresponding to each of the aforementioned pairs of magnets are arranged on the same surface of the coil holding portion. 【0007】 However, increasing thrust requires a larger current to flow through the coil, which poses the problem of having to increase the horizontal size of the voice coil motor. 【0008】 In view of the above issues, this disclosure aims to provide a voice coil motor that improves the overall thrust of the voice coil motor while suppressing an increase in horizontal size. [Means for solving the problem] 【0009】 To solve the above problems, the voice coil motor according to this embodiment is a voice coil motor having a magnet unit and a coil unit. When the magnet unit is a movable element, the coil unit is a stator, and when the magnet unit is a stator, the coil unit is a movable element. The magnet unit has a first magnet holder, a second magnet holder, and a third magnet holder, which are relatively fixed and have a hierarchical structure in a predetermined direction. The coil unit has a first coil holder having a first coil and a second coil holder having a second coil, which are relatively fixed and have a hierarchical structure in a predetermined direction. The first magnet holder has a first surface and a second surface opposite to the first surface, and on the second surface, opposite the first coil holder, there are a first magnet of first polarity and a second magnet of second polarity, which are aligned in a first direction intersecting a predetermined direction. The second magnet holder has a third surface and a fourth surface opposite to the third surface. On the third surface, opposite to the first coil holder, are a third magnet of second polarity and a fourth magnet of first polarity, aligned in order in a first direction. On the fourth surface, opposite to the second coil holder, are a fifth magnet of first polarity and a sixth magnet of second polarity, aligned in order in a third direction intersecting the first direction. The third magnet holder has a fifth surface and a sixth surface opposite to the fifth surface. On the fifth surface, are a seventh magnet of second polarity and an eighth magnet of first polarity, aligned in order in a third direction, opposite to the second coil holder. The voice coil motor is configured such that the first magnet holder, the second magnet holder, and the first coil holder work together to enable the movement of the moving element in a first direction and in a second direction which is the opposite of the first direction, and the second magnet holder, the third magnet holder, and the second coil holder work together to enable the movement of the moving element in a third direction and in a fourth direction which is the opposite of the third direction. [Effects of the Invention] 【0010】 According to the voice coil motor of this embodiment, it is possible to improve the thrust of the voice coil motor as a whole while suppressing an increase in the horizontal size. [Brief explanation of the drawing] 【0011】 [Figure 1]Figure 1 is a perspective view of the voice coil motor system according to this embodiment. [Figure 2] Figure 2 is an exploded view of the voice coil motor system shown in Figure 1. [Figure 3] Figure 3 is a front view of the voice coil motor shown in Figure 2. [Figure 4] Figure 4 is a top view of the voice coil motor shown in Figure 2. [Figure 5] Figure 5 is a cross-sectional view of the voice coil motor shown in Figure 3, along line AA. [Figure 6] Figure 6 is a cross-sectional view of the voice coil motor shown in Figure 4, along the BB line. [Figure 7] Figure 7 is a perspective view of the magnet unit shown in Figure 2. [Figure 8] Figure 8 is a top view of the first magnet holder shown in Figure 7. [Figure 9] Figure 9 is a top view of the second magnet holder shown in Figure 7. [Figure 10] Figure 10 is a conceptual diagram showing how the magnet is attached to the main body of the holder. [Figure 11] Figure 11 shows the case where a groove is formed at the position where the magnet is attached. (a) is a view from the fourth surface 392 side, (b) is a cross-sectional view along line CC shown in (a), and (c) is a cross-sectional view along line DD shown in (a). [Figure 12] Figure 12 is a top view of the third magnet holder shown in Figure 7. [Figure 13] Figure 13 is a perspective view of the coil unit shown in Figure 2. [Figure 14] Figure 14 is a top view of the first coil holder shown in Figure 13. [Figure 15] Figure 15 is a top view of the second coil holding section shown in Figure 13. [Figure 16] Figure 16 is a diagram illustrating the relationship between the second surface of the first magnet holder, the third surface of the second magnet holder, and the first coil holder. [Figure 17]FIG. 17 is a diagram for explaining the relationship between the fourth surface of the second magnet holding portion, the fifth surface of the third magnet holding portion, and the second coil holding portion. [Figure 18] FIG. 18 is an external perspective view of an image blur correction device to which a position detection device according to an embodiment of the prior art is applied. [Figure 19] FIG. 19 is an external perspective view showing a fixed portion of the image blur correction device of FIG. 18. [Figure 20] FIG. 20 is an external perspective view showing the state of the movable portion of the image blur correction device of FIG. 18 with the imaging unit mounted as viewed from the direction of arrow [5] in FIG. 18 (the back side). 【Embodiments for Carrying Out the Invention】 【0012】 Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following description, components having the same function are denoted by the same reference numerals, and redundant description is omitted. 【0013】 <<Voice Coil Motor System 100>> FIG. 1 is a perspective view of a voice coil motor system according to the present embodiment. FIG. 2 is an exploded view of the voice coil motor system shown in FIG. 1. As shown in FIGS. 1 and 2, the voice coil motor system 100 according to the present embodiment is composed of a voice coil motor 1, an air stage 2, and an encoder 3. 【0014】 <Air Stage 2> The air stage 2 is a device for levitating the voice coil motor 1. The air stage 2 is composed of a base 2a and a stage 2b mounted on the base 2a. 【0015】 In this example, the base 2a has an overall roughly rectangular parallelepiped shape, with an upper surface 2aa on the upper side (+z direction) and a lower surface 2ab on the lower side (-z direction). The base 2a has a hollow shape with a hole 2a6. The size of the hole 2a6 is slightly larger than the outer shape of the stage 2b in the horizontal plane (xy plane), and its depth is such that the entire stage base 2b3 and stage body 2b2, as well as a part of the movable element connection part 2b1, can be inserted into it. 【0016】 Stage 2b consists of a movable component connector 2b1, a stage body 2b2, and a stage base 2b3. The movable component connector 2b1 and the stage body 2b2, and the stage body 2b2 and the stage base 2b3 are fixed together by fasteners such as bolts (not shown). The stage base 2b3 has a thin rectangular parallelepiped shape with a through hole in the center through which the bottom surface of the stage body 2b2 is exposed. The stage base 2b3 has portions that protrude downward at both ends in the longitudinal direction. The stage body 2b2 is mounted on the stage base 2b3. The stage body 2b2 has a thin rectangular parallelepiped shape with a rectangle similar to that of the stage base 2b3. The movable component connector 2b1 is mounted on the stage body 2b2. The movable component connector 2b1 has a thin rectangular parallelepiped shape with a rectangle similar to that of the stage base 2b3. The movable connector portion 2b1 has protruding portions at both of its longitudinal ends for fixing the magnet unit 10 through bolts. A bolt insertion hole portion 2b4 is provided on the upper surface of the protruding portion. 【0017】 The first fixing plate 11A of the magnet unit 10 is mounted on the movable connector section 2b1, and bolts are inserted through the bolt insertion holes 2b4, so that in this example, the magnet unit 10, which is the movable element, and the stage 2b are fixed together and become one unit. The second fixing plates 51Aa and 51Ab (hereinafter collectively referred to as "second fixing plate 51A") of the coil unit 50 are mounted on the upper surface 2aa of the base 2a, and bolts are inserted through the bolt insertion holes 2a5, so that in this example, the coil unit 50, which is the stator, and the base 2a are fixed together and become one unit. 【0018】 The base 2a has numerous tiny holes (not shown) through which compressed air passes from its lower surface 2ab to its upper surface. Compressed air is sent into these holes from the lower surface of the base 2a and discharged into the holes 2a6. The discharged compressed air is configured to be blown onto the lower surface of the stage body 2b2 via the stage base 2b3. By blowing compressed air onto the stage 2b, the stage 2b and the magnet unit 10 levitate upward (towards the +z direction) relative to the base 2a and the coil unit 50. 【0019】 <Encoder 3> The encoder 3 is a device for detecting the movement position of the voice coil motor 1. The encoder 3 consists of an encoder body 3a and a reflector 3b. The encoder body 3a emits light, which is reflected by the reflector 3b, and its position is detected from the reflected light. The reflector 3b reflects the received light. That is, the encoder 3 works as follows: The encoder body 3a emits light toward the reflector 3b. The emitted light is reflected by the reflector 3b, which is fixed to the magnet unit 10, which is the moving element. The reflected light is received by the encoder body 3a. The encoder body 3a detects the position of the reflector 3b from the received light. The reflector 3b is fixed to the magnet unit 10, for example, by bolts. Therefore, the position of the reflector 3b detected by the encoder body 3a can be considered to be the position of the magnet unit 10. Thus, the encoder 3 detects the movement position of the voice coil motor 1. 【0020】 <Voice coil motor 1> The voice coil motor 1 is lightweight, has a fast response speed, and allows for precise control, making it suitable for use in products requiring high-precision positioning and high-speed vibration, such as hard disk drives and digital cameras. While the voice coil motor 1 in this example is small, measuring approximately 90mm x 70mm x 70mm, there are no limitations on the size or weight of the voice coil motors disclosed in this disclosure; the above is merely an example. The voice coil motor 1 according to this embodiment will now be described. 【0021】 Figure 3 is a front view of the voice coil motor shown in Figure 2. Figure 4 is a top view of the voice coil motor shown in Figure 2. Figure 5 is a cross-sectional view of the voice coil motor shown in Figure 3 along line AA. Figure 6 is a cross-sectional view of the voice coil motor shown in Figure 4 along line BB. 【0022】 As shown in Figures 2 to 6, the voice coil motor 1 has a magnet unit 10 and a coil unit 50. As will be described later, the voice coil motor 1 is configured such that the first magnet holder 20A and the second magnet holder 30A of the magnet unit 10 and the first coil holder 60 of the coil unit 50 cooperate to enable relative movement in the +x direction (hereinafter also referred to as "first direction C1") or the -x direction (hereinafter also referred to as "second direction C2"). As will be described later, the voice coil motor 1 is configured such that the second magnet holder 30A and the third magnet holder 40A of the magnet unit 10 and the second coil holder 70 of the coil unit 50 cooperate to enable relative movement in the +y direction (hereinafter also referred to as "third direction C3") or the -y direction (hereinafter also referred to as "fourth direction C4"). 【0023】 (Magnetic unit 10) Figure 7 is a perspective view of the magnet unit shown in Figure 2. As shown in Figure 7, the magnet unit 10 has a first magnet holder 20A, a second magnet holder 30A, and a third magnet holder 40A. The magnet unit 10 has a hierarchical structure in which the first magnet holder 20A, the second magnet holder 30A, and the third magnet holder 40A are relatively fixed by a pair of first fixing plates 11A made of a rigid material such as stainless steel. In this example, the second magnet holder 30A is hierarchically positioned above the third magnet holder 40A (+z direction). The first magnet holder 20A is hierarchically positioned above the second magnet holder 30A (+z direction). Each first fixing plate 11A is relatively fixed to the first magnet holder 20A, the second magnet holder 30A, and the third magnet holder 40A by fastening them with bolts 12. 【0024】 [First magnet holding part 20A] Figure 8 is a top view of the first magnet holder shown in Figure 7. In Figure 8, the first magnets 21b, 23b and the second magnets 22b, 24b, which would normally not be visible, are indicated by dotted lines. In Figure 8, the holes formed in the main body 29 of the holder shown in Figure 7 are not shown. In Figure 8, for the sake of explanation, "N" or "S" is added to indicate polarity. The same point about adding polarity is also true for Figures 9 to 12. 【0025】 The first magnet holder 20A has a holder body 29 made of a rigid member of a magnetic material such as soft iron (yoke), and a plurality of magnets. In this example, the holder body 29 has a plate-like rectangular parallelepiped shape with a first surface 291 (Figure 5) on the upper side (+z direction) and a second surface 292 on the lower side (-z direction), which is the opposite side of the first surface 291. However, the holder body 29 may have other shapes, such as a cylinder, as long as it has one surface and the opposite surface. In this disclosure, the magnet having a first polarity mounted on the second surface 292 is referred to as the "first magnet," and the magnet having a second polarity is referred to as the "second magnet." The first magnet and the second magnet have opposing polarities. Hereinafter, in this example, the first magnet will be described as the N pole and the second magnet as the S pole. However, in the voice coil motor 1 of this disclosure, the first magnet may be the S pole and the second magnet may be the N pole. The fact that the first magnet holder 20A may have other shapes, such as a cylindrical shape, and that the first magnet may be the south pole and the second magnet the north pole, also applies to the second magnet holder 30A and the third magnet holder 40A, which will be described later. The magnets described in this disclosure are magnets having two polarities. That is, they have a first polarity on one side and a second polarity on the opposite side and are integrated together. Therefore, in this disclosure, for example, "the first magnet having the first polarity (north pole)" or "the first magnet with the first polarity" refers to the polarity furthest from the surface on which it is mounted, unless otherwise specified. That is, for example, "the first magnet having the first polarity (north pole)" or "the first magnet with the first polarity" means the first magnet with the second polarity (south pole) side mounted on the surface. 【0026】 When two adjacent magnets with opposite polarities are counted as one pair, at least one pair of magnets is provided on the second surface 292. In this example, the first magnet holder 20A has a total of two pairs (four magnets) mounted on it: the first magnet 21b and the second magnet 22b, and the first magnet 23b and the second magnet 24b. The four magnets are mounted alternately, with the first magnets and the second magnets alternating. In this example, the four magnets are mounted aligned in the x-axis direction. As previously stated, in this disclosure, the +x direction is also referred to as the "first direction C1," and the -x direction as the "second direction C2." The first direction C1 can also be said to be the direction that intersects with the z-axis direction, which has a hierarchical structure. That is, on the second surface 292 of the holder body 29, two first magnets and two second magnets are mounted alternately in the x-axis direction. In other words, the first magnet holder 20A has a first surface 291 and a second surface 292 opposite to the first surface 291, on which a first magnet of first polarity and a second magnet of second polarity are mounted, alternately aligned in the first direction C1 or the second direction C2 which is the opposite direction of the first direction C1. As will be described later, the first magnet holder 20A has a first magnet of first polarity and a second magnet of second polarity facing the first coil holder 60. 【0027】 [Second magnet holding part 30A] Figure 9 is a top view of the second magnet holder shown in Figure 7. In Figure 9, the fifth magnets 35b, 37b and the sixth magnets 36b, 38b, which would normally be invisible, are indicated by dotted lines. The second magnet holder 30A has a holder body 39 made of a rigid member of a magnetic material such as soft iron (yoke), and a plurality of magnets. In this example, the holder body 39 has the shape of a plate-like rectangular parallelepiped having a third surface 391 (Figure 5) on the upper side (+z direction side) and a fourth surface 392 on the lower side (-z direction side), which is the opposite side of the third surface 391. In this disclosure, the magnet having the second polarity (S pole in this example) mounted on the third surface 391 is referred to as the "third magnet," and the magnet having the first polarity (N pole in this example) is referred to as the "fourth magnet." In this disclosure, the magnet having the first polarity mounted on the fourth surface 392 is referred to as the "fifth magnet," and the magnet having the second polarity is referred to as the "sixth magnet." 【0028】 In this example, the second magnet holder 30A has two sets (four magnets) mounted on its third surface 391: the third magnet 31b and the fourth magnet 32b, and the third magnet 33b and the fourth magnet 34b. The four magnets are mounted alternately, with the third and fourth magnets alternating. In this example, the four magnets are mounted aligned in the x-axis direction. That is, the holder body 39 has two third magnets and two fourth magnets mounted alternately in the x-axis direction on its third surface 391. In other words, the second magnet holder 30A has a third surface 391 on which the third magnet with second polarity and the fourth magnet with first polarity are mounted alternately in the first direction C1 or the second direction C2. As will be described later, in the second magnet holder 30A, the third magnet faces the first magnet via the first coil holder 60, and the fourth magnet faces the second magnet via the first coil holder 60. 【0029】 In this example, the second magnet holder 30A has two sets (four magnets) mounted on its fourth surface 392: the fifth magnet 35b and the sixth magnet 36b, and the fifth magnet 37b and the sixth magnet 38b. The four magnets are mounted alternately, with the fifth magnet and the sixth magnet alternating. In this example, the four magnets are mounted in two rows aligned in the y-axis direction. As previously stated, in this disclosure, the +y direction is also referred to as the "third direction C3," and the -y direction as the "fourth direction C4." The third direction C3 can also be said to be the direction that intersects the first direction C1. That is, the holder body 39 has two parallel rows on its fourth surface 392 in which the fifth magnet and the sixth magnet are mounted alternately in the y-axis direction. In other words, the second magnet holder 30A has a fourth surface 392 on the opposite side of the third surface 391, in which the fifth magnet of the first polarity and the sixth magnet of the second polarity are mounted alternately in the third direction C3, which intersects the first direction C1, or in the fourth direction C4, which is the opposite direction of the third direction C3, forming two rows in this example. In this example, the third direction C3 is the direction obtained by rotating 90 degrees counterclockwise from the first direction C1 on the xy plane from the viewpoint of Figure 9. 【0030】 In Figure 9, the opposing magnets in adjacent rows on the fourth surface 392 are magnets of the same polarity. Specifically, the fifth magnet 35b and the fifth magnet 37b have the same polarity (N pole in this example), and the sixth magnet 36b and the sixth magnet 38b have the same polarity (S pole in this example). However, the opposing magnets in adjacent rows on the fourth surface 392 may have different polarities. For example, the opposing magnet in the adjacent row to the fifth magnet 35b may be the sixth magnet 38b, which has a different polarity from the fifth magnet 35b, and the opposing magnet in the adjacent row to the sixth magnet 36b may be the fifth magnet 37b, which has a different polarity from the sixth magnet 36b. In this case, on the fifth surface 491, the opposing magnet in the adjacent row of the seventh magnet 41b will be the eighth magnet 44b, which has a different polarity from the seventh magnet 41b, and the opposing magnet in the adjacent row of the eighth magnet 42b will be the seventh magnet 43b, which has a different polarity from the eighth magnet 42b. 【0031】 In the configuration shown in Figure 9, when current flows in the same direction through two parallel second coils 71 (see Figure 15), a thrust force acts on the magnet unit 10 in the same direction. When current flows in different directions through two parallel second coils 71, thrust forces act on the magnet unit 10 in opposite directions. In the configuration shown in Figure 9, if the opposing magnets in adjacent rows of the fifth magnet 35b are designated as the sixth magnet 38b, and the opposing magnets in adjacent rows of the sixth magnet 36b are designated as the fifth magnet 37b, the thrust forces described above act in the opposite direction. That is, when current flows in the same direction through two parallel second coils 71 (see Figure 15), thrust forces act on the magnet unit 10 in opposite directions. When current flows in different directions through two parallel second coils 71, thrust forces act on the magnet unit 10 in the same direction. 【0032】 The second magnet holder 30A has a third magnet of second polarity and a fourth magnet of first polarity on one side (third surface 391) facing the first coil holder 60. The second magnet holder 30A has a fifth magnet of first polarity and a sixth magnet of second polarity on the other side (fourth surface 392) facing the second coil holder 70. 【0033】 Figure 10 is a conceptual diagram showing how to attach a magnet to the main body of the holder. Figure 10 shows the process of placing a sixth magnet 38b, which is a magnet of opposite polarity, in an adjacent row, after the fifth magnet 35b has already been placed on the fourth surface 392 of the main body of the holder 39. In order to place the sixth magnet 38b, when the sixth magnet 38b, which has a south pole, is brought closer to the fifth magnet 35b, which has a north pole, from the right side from the viewpoint shown in Figure 10, an attractive force acts between the north pole of the fifth magnet 35b and the south pole of the sixth magnet 38b. The sixth magnet 38b is mounted in the desired position while being subjected to this attractive force. 【0034】 On the other hand, consider the case where opposing magnets in adjacent rows are placed with the same polarity, as shown in Figure 9. This corresponds, for example, to the case where the sixth magnet 38b is replaced with the fifth magnet 37b in Figure 10. In order to place the fifth magnet 37b, if the fifth magnet 37b, which has a north pole, is brought closer to the fifth magnet 35b, which has a north pole, from the right side from the viewpoint in Figure 10, a repulsive force will act between the north poles of the fifth magnet 35b and the fifth magnet 37b. The fifth magnet 37b is then mounted in the desired position while subjected to this repulsive force. 【0035】 Figure 11 shows the case where grooves are formed at the positions where magnets are attached. (a) is a view from the fourth surface 392 side, (b) is a cross-sectional view along line CC shown in (a), and (c) is a cross-sectional view along line DD shown in (a). In Figure 11, opposing magnets in adjacent rows are magnets of different polarities. Depending on the configuration of the voice coil motor, when attaching magnets to the holding body, for example, an attractive force acts between two magnets, which may cause them to collide and potentially damage one or both magnets. Alternatively, a repulsive force acts between two magnets, which may prevent them from being placed in the designated position, or may require a long time to place them. The voice coil motor 1 of this disclosure, as shown in Figure 11, may have grooves 39m1 to 39m4 in the holding body 39 that are slightly larger than the outer shape of the magnets (allowing the magnets to be fitted into them) at the positions where the magnets are placed. In this example, the grooves 39m1 to 39m4 are configured to be shallower than the thickness of the magnets and to cover the perimeter of each magnet. However, the depth of the grooves may be adjusted as appropriate, making them deeper or shallower. In this example, the grooves 39m1 to 39m4 effectively form walls around the magnets, facilitating their positioning and restricting their movement. Since the goal is simply to restrict the positioning and movement of the magnets, instead of the grooves described above, walls may be provided that protrude from the fourth surface 392 to cover the perimeter of the magnets. The grooves and walls described above are not limited to covering the entire perimeter of the magnets; they may also be configured to cover only a portion of the perimeter. 【0036】 [Third magnet holding part 40A] Figure 12 is a top view of the third magnet holder shown in Figure 7. The third magnet holder 40A has a holder body 49 made of a rigid member of a magnetic material such as soft iron (yoke), and a plurality of magnets. In this example, the holder body 49 has the shape of a plate-like rectangular parallelepiped having a fifth face 491 (Figure 5) on the upper side (+z direction side) and a sixth face 492 on the lower side (-z direction side), which is the opposite side of the fifth face 491. In this disclosure, the magnet having the second polarity (S pole in this example) mounted on the fifth face 491 is referred to as the "seventh magnet," and the magnet having the first polarity (N pole in this example) is referred to as the "eighth magnet." 【0037】 In this example, the third magnet holder 40A has two sets (four magnets) mounted on its fifth surface 491: the seventh magnet 41b and the eighth magnet 42b, and the seventh magnet 43b and the eighth magnet 44b. The four magnets are mounted alternately, with the seventh and eighth magnets alternating. In this example, the four magnets are mounted in two rows aligned in the y-axis direction. That is, the holder body 49 has two parallel rows on its fifth surface 491 in which the seventh and eighth magnets are mounted alternately in the y-axis direction. In other words, the third magnet holder 40A has a fifth surface 491 in which the seventh magnet of second polarity and the eighth magnet of first polarity are mounted alternately in the third direction C3 or the fourth direction C4, forming two rows in this example. The third magnet holder 40A also has a sixth surface 492, which is the surface opposite to the fifth surface 491. 【0038】 The third magnet holder 40A has a seventh magnet of second polarity and an eighth magnet of first polarity, facing the second coil holder 70. The third magnet holder 40A is arranged such that the seventh magnet faces the fifth magnet via the second coil holder 70, and the eighth magnet faces the sixth magnet via the second coil holder 70. 【0039】 [First fixed plate 11A] Each of the pair of first fixing plates 11A has a roughly rectangular plate shape, as shown in Figure 7. The first fixing plate 11A integrates the first magnet holder 20A, the second magnet holder 30A, and the third magnet holder 40A by fastening them to the sides of each of the magnet holders along their longitudinal directions with bolts 12. The length of the roughly rectangular first fixing plate 11A in the horizontal direction (horizontal direction, x-axis direction) is long enough to cover all of the sides of the magnet holders along their longitudinal directions. The length of the roughly rectangular first fixing plate 11A in the vertical direction (vertical direction, z-axis direction) is such that it covers the entire length (height) when the plates are layered with a predetermined gap between the third magnet holding part 40A and the second magnet holding part 30A, and a predetermined gap between the second magnet holding part 30A and the first magnet holding part 20A. 【0040】 The first fixing plate 11A has a hierarchical structure for the first magnet holding part 20A, the second magnet holding part 30A, and the third magnet holding part 40A, by fixing them with bolts 12. 【0041】 (Coil unit 50) Figure 13 is a perspective view of the coil unit shown in Figure 2. As shown in Figure 13, the coil unit 50 has a first coil holder 60 having a first coil 61 and a second coil holder 70 having a second coil 71. The coil unit 50 has a hierarchical structure in which the first coil holder 60 and the second coil holder 70 are relatively fixed by second fixing plates 51Aa and 51Ab made of a rigid material such as stainless steel. In this example, the first coil holder 60 is hierarchically positioned above the second coil holder 70 (in the +z direction). The second fixing plates 51Aa and 51Ab relatively fix the first coil holder 60 and the second coil holder 70 by fastening them with bolts 52. 【0042】 [First coil holding section 60] Figure 14 is a top view of the first coil holder shown in Figure 13. The first coil holder 60 consists of a roughly rectangular flat plate holder base 69 having a hole 691 in the center, two first coils 61 provided in this example within the hole 691, and a joint 62 for joining the first coils 61 and the holder base 69. The holder base 69 is formed from a rigid member such as stainless steel. The joint 62 is formed from a thermosetting resin, for example. 【0043】 The first coil 61 is a conductive member in which thin metal wires, such as copper, are wound in a ring shape multiple times. The first coil 61 is a member wound in a ring shape with the third direction C3 or the fourth direction C4 as the longitudinal direction and the first direction C1 or the second direction C2 as the short direction. 【0044】 In this disclosure, "winding in a ring" means, for example, winding through at least the first direction C1, third direction C3, second direction C2, and fourth direction C4 in that order, or winding through at least the second direction C2, third direction C3, first direction C1, and fourth direction C4 in that order. However, these are merely examples, and the first direction C1 or second direction C2 is not necessarily the first direction of winding. The winding may also be configured to start from the third direction C3 or the fourth direction C4. 【0045】 The first coil holder 60 has one first coil 61 for every four magnets: one pair of first and second magnets adjacent to each other on the second surface 292, and one pair of third and fourth magnets adjacent to each other on the third surface 391, facing the first and second magnets via the first coil holder 60. In this disclosure, in the view of Figure 14, the first coil 61 located on the left side is referred to as "first coil 61a," and the first coil 61 located on the right side is referred to as "first coil 61b." The first coil 61a is the coil corresponding to the first magnet 21b and second magnet 22b on the second surface 292 and the third magnet 31b and fourth magnet 32b on the third surface 391. The first coil 61b is the coil corresponding to the first magnet 23b and second magnet 24b on the second surface 292 and the third magnet 33b and fourth magnet 34b on the third surface 391. The first coil 61a and the first coil 61b are arranged in alignment along the x-axis. 【0046】 The two first coils 61 are connected as a single wiring. In this example, the first coils 61 are wound in the same direction. In Figure 14, the connecting wires from each first coil 61 to the cable 63 are not visible, but the cable 63 is connected to a control unit (not shown) that controls the current. That is, the current input from one side of the cable 63 flows in the same direction through the first coils 61a and 61b, and then flows to the other side of the cable 63. Note that in the voice coil motor 1 of this disclosure, the first coils 61 do not need to be connected and may be wired separately, as long as it is possible to control the current flowing in the same direction through the first coils 61a and 61b. 【0047】 [Second coil holding section 70] Figure 15 is a top view of the second coil holder shown in Figure 13. The second coil holder 70 consists of a roughly rectangular flat plate holder base 79 having a hole 791 in the center, two second coils 71 provided in this example within the hole 791, and a joint 72 for joining the second coils 71 and the holder base 79. The holder base 79 is formed from a rigid member such as stainless steel. The joint 72 is formed from a thermosetting resin, for example. 【0048】 The second coil 71 is a conductive member in which thin metal wires, such as copper, are wound in a ring shape multiple times. The second coil 71 is a member wound in a ring shape with the first direction C1 or the second direction C2 as the longitudinal direction and the third direction C3 or the fourth direction C4 as the short direction. 【0049】 The second coil holder 70 has one second coil 71 for every four magnets: one pair of adjacent fifth and sixth magnets on the fourth surface 392, and one pair of adjacent seventh and eighth magnets on the fifth surface 491 that face the pair of fifth and sixth magnets via the second coil holder 70. In this disclosure, the second coil 71 located on the left side in the view of Figure 15 is referred to as "second coil 71a," and the second coil 71 located on the right side is referred to as "second coil 71b." The second coil 71a is the coil corresponding to the fifth magnet 35b and sixth magnet 36b on the fourth surface 392, and the seventh magnet 41b and eighth magnet 42b on the fifth surface 491. The second coil 71b is the coil corresponding to the fifth magnet 37b and sixth magnet 38b on the fourth surface 392, and the seventh magnet 43b and eighth magnet 44b on the fifth surface 491. The second coil 71a and the second coil 71b are arranged in alignment along the x-axis. 【0050】 The second coils 71a and 71b of this disclosure are configured to be individually controllable. For example, the second coils 71a and 71b can both carry current in the same direction, or they can carry current in opposite directions. Alternatively, current can be carried only through the second coil 71a, or only through the second coil 71b. In Figure 15, the connecting wires from each second coil 71 to cables 73 and 74 are not visible, but in this example, cable 73 is for the second coil 71a, and cable 74 is for the second coil 71b. Cables 73 and 74 are connected to a control unit (not shown) that controls the current. 【0051】 [Second fixed plate 51A] The second fixing plates 51Aa and 51Ab have a roughly rectangular plate shape, as shown in Figure 13. The second fixing plates 51Aa and 51Ab are fastened to the sides of the first coil holding portion 60 and the second coil holding portion 70, respectively, along their shorter sides, by bolts 52, thereby integrating the first coil holding portion 60 and the second coil holding portion 70. The second fixing plate 51Aa has a hole 514 (Figure 6) for inserting cables 63, 73, and 74. The second fixing plate 51Aa has the same shape as the second fixing plate 51Ab except for having the hole 514. The length of the roughly rectangular second fixing plates 51Aa and 51Ab in the lateral direction (horizontal direction, y-axis direction) is long enough to cover all of the sides of the first coil holding portion 60 and the second coil holding portion 70 along their shorter sides, and in this example, it is formed to be longer than the length of the magnet unit 10 in the y-axis direction (see Figures 1 and 2). The length of the roughly rectangular second fixing plates 51Aa and 51Ab in the vertical direction (vertical direction, z-axis direction), including the bolt fastening parts that protrude upward and downward, is longer than the length of the first fixing plate 11A (see Figures 1 and 2). In other words, the height is sufficient to cover all of the third magnet holder 40A, second coil holder 70, second magnet holder 30A, first coil holder 60, and first magnet holder 20A, which are arranged with predetermined gaps between them, starting from the bottom (-z direction). The upper ends (+z-axis direction) of the second fixing plates 51Aa and 51Ab have bolt fastening parts that protrude upward, and the encoder 3 (encoder body 3a) is mounted on this part from above and bolted together, thereby integrating the voice coil motor 1 (coil unit 50) and the encoder 3 (encoder body 3a). The lower ends of the second fixing plates 51Aa and 51Ab have bolt fastening portions that protrude downward. The second fixing plates 51Aa and 51Ab are mounted from above the base 2a, and bolts are inserted through the bolt insertion holes 2a5 and fastened with bolts, thereby integrating the voice coil motor 1 (coil unit 50) and the air stage 2 (base 2a). 【0052】 The second fixing plates 51Aa and 51Ab secure the first coil holding section 60 and the second coil holding section 70 to each other with bolts 52, thereby creating a hierarchical structure for the first coil holding section 60 and the second coil holding section 70. 【0053】 (Configuration consisting of magnet unit 10 and coil unit 50) The assembled voice coil motor 1 has the magnet unit 10 and the coil unit 50 integrated into one unit. In other words, unless the bolts 12 and 52 are released, the magnet unit 10 and the coil unit 50 cannot be separated as separate components under normal operating conditions. In other words, the voice coil motor 1 cannot be assembled from the assembled magnet unit 10 shown in Figure 7 and the assembled coil unit 50 shown in Figure 13. 【0054】 When assembling the voice coil motor 1, for example, at least some of the bolts 12 and bolts 52 should be left unfastened, and the components of the voice coil motor 1 should be arranged as shown in Figures 3 and 5. Then, the unfastened bolts 12 and bolts 52 should be fastened. Alternatively, an assembled magnet unit 10 and a coil unit 50 with one of the second fixing plates 51A unfastened by bolt 52 should be prepared, and the components of the voice coil motor 1 should be arranged as shown in Figures 3 and 5. Then, the unfastened second fixing plate 51A should be fastened with bolt 52 and assembled. 【0055】 The voice coil motor 1 assembled in this manner has the following configurations: (1) The magnet unit 10 and the coil unit 50 are configured such that at least a portion of the first coil 61 wound in the fourth direction C4 faces the first magnet and the third magnet, respectively, with a predetermined gap between them. (2) The magnet unit 10 and the coil unit 50 are configured such that at least a portion of the first coil 61 wound in the third direction C3 faces the second magnet and the fourth magnet, respectively, with a predetermined gap between them. (3) The magnet unit 10 and the coil unit 50 are configured such that at least a portion of the second coil 71 wound in the first direction C1 faces the fifth magnet and the seventh magnet, respectively, with a predetermined gap between them. (4) The magnet unit 10 and the coil unit 50 are configured such that at least a portion of the second coil 71 wound in the second direction C2 faces the sixth magnet and the eighth magnet, respectively, with a predetermined gap between them. Alternatively, (5) the magnet unit 10 and coil unit 50 are configured such that at least a portion of the first coil 61 wound in the third direction C3 faces the first magnet and the third magnet, respectively, with a predetermined gap between them. (6) The magnet unit 10 and coil unit 50 are configured such that at least a portion of the first coil 61 wound in the fourth direction C4 faces the second magnet and the fourth magnet, respectively, with a predetermined gap between them. (7) The magnet unit 10 and coil unit 50 are configured such that at least a portion of the second coil 71 wound in the second direction C2 faces the fifth magnet and the seventh magnet, respectively, with a predetermined gap between them. (8) The magnet unit 10 and coil unit 50 are configured such that at least a portion of the second coil 71 wound in the first direction C1 faces the sixth magnet and the eighth magnet, respectively, with a predetermined gap between them. 【0056】 Figure 16 is a diagram illustrating the relationship between the second surface of the first magnet holder, the third surface of the second magnet holder, and the first coil holder. In Figure 16, the first magnet 21b and the third magnet 31b are in overlapping positions, the second magnet 22b and the fourth magnet 32b are in overlapping positions, and they face the first coil 61, which is shown by the dashed line. The first magnet 23b and the third magnet 33b are in overlapping positions, the second magnet 24b and the fourth magnet 34b are in overlapping positions, and they face the first coil 61, which is shown by the dashed line. In this example, the first magnet 21b, which is the north pole, and the third magnet 31b, which is the south pole, are subjected to a magnetic force in the direction from the first magnet 21b to the third magnet 31b (-z direction). In this case, by controlling the voice coil motor 1, if current is passed through the first coil 61 in a counterclockwise direction from the viewpoint shown in Figure 16, a thrust force acts on the magnet unit 10 in the rightward direction (+x direction, first direction C1) because the coil unit 50 is fixed to the air stage 2. The second magnet 22b, which is the south pole, and the fourth magnet 32b, which is the north pole, have a magnetic force acting from the fourth magnet 32b towards the second magnet 22b (+z direction). If current is passed in a counterclockwise direction from the viewpoint shown in Figure 16, a thrust force acts on the magnet unit 10 in the rightward direction (+x direction, first direction C1). On the other hand, if current is passed in a clockwise direction from the viewpoint shown in Figure 16, a thrust force acts on the magnet unit 10 in the leftward direction (-x direction, second direction C2). 【0057】 The same relationship applies between the first magnet 23b and the third magnet 33b, and between the second magnet 24b and the fourth magnet 34b. In other words, the voice coil motor 1 is configured such that the first magnet holder 20A and the second magnet holder 30A of the magnet unit 10 and the first coil holder 60 of the coil unit 50 cooperate to enable the movement of the magnet unit 10, which is a moving element in the first direction C1 and the second direction C2 (i.e., the x-axis direction) as shown in Figure 16. 【0058】 Figure 17 is a diagram illustrating the relationship between the fourth surface of the second magnet holder, the fifth surface of the third magnet holder, and the second coil holder. In Figure 17, the fifth magnet 35b and the seventh magnet 41b are in overlapping positions, the sixth magnet 36b and the eighth magnet 42b are in overlapping positions and face the second coil 71, indicated by the dashed line. The fifth magnet 37b and the seventh magnet 43b are in overlapping positions, the sixth magnet 38b and the eighth magnet 44b are in overlapping positions and face the second coil 71, indicated by the dashed line. In this example, the fifth magnet 35b, which is the north pole, and the seventh magnet 41b, which is the south pole, are subjected to a magnetic force in the direction from the fifth magnet 35b to the seventh magnet 41b (-z direction). In this case, by controlling the voice coil motor 1, if current is passed through the second coil 71 in a counterclockwise direction, for example from the viewpoint shown in Figure 17, a thrust acts upward (+y direction, third direction C3) on the magnet unit 10 because the coil unit 50 is fixed to the air stage 2. The sixth magnet 36b, which is the south pole, and the eighth magnet 42b, which is the north pole, have a magnetic force acting from the sixth magnet 36b towards the eighth magnet 42b (+z direction). If current is passed counterclockwise from the viewpoint shown in Figure 17, a thrust acts upward (+y direction, third direction C3) on the magnet unit 10. On the other hand, if current is passed clockwise from the viewpoint shown in Figure 17, a thrust acts downward (-y direction, fourth direction C4) on the magnet unit 10. From the viewpoint shown in Figure 17, if current is passed counterclockwise through the second coil 71a on the left and clockwise through the second coil 71b on the right, a thrust force acts upward (+y direction, third direction C3) on the left side of the magnet unit and a thrust force acts downward (-y direction, fourth direction C4) on the right side of the magnet unit, causing the magnet unit 10 to rotate clockwise. Changing the direction of the current changes the direction of rotation. 【0059】 The same relationship applies between the fifth magnet 37b and the seventh magnet 43b, and between the sixth magnet 38b and the eighth magnet 44b. In other words, the voice coil motor 1 is configured such that the second magnet holding portion 30A and the third magnet holding portion 40A of the magnet unit 10 and the second coil holding portion 70 of the coil unit 50 cooperate to enable the movement of the magnet unit 10, which is a moving element in the third direction C3 and the fourth direction C4 (i.e., the y-axis direction) as shown in Figure 17. 【0060】 Therefore, the voice coil motor 1 is configured to be able to move within a predetermined range while maintaining the states described in (1) to (4) or (5) to (8) above. 【0061】 The voice coil motor 1 of this disclosure is configured to control the voice coil motor in two dimensions, x and y. In the voice coil motor 1 of this disclosure, movement in the first direction C1 and the second direction C2 (x-axis direction) is performed in coordination by the first magnet holder 20A, the second magnet holder 30A, and the first coil holder 60. Movement in the third direction C3 and the fourth direction C4 (y-axis direction), or in the rotational direction, is performed in coordination by the second magnet holder 30A, the third magnet holder 40A, and the second coil holder 70. 【0062】 The voice coil motor 1 of this disclosure is layered with a second magnet holder 30A located above (+z direction) the third magnet holder 40A, and a first magnet holder 20A located above (+z direction) the second magnet holder 30A. The second coil holder 70 is provided so as to be located between the third magnet holder 40A and the second magnet holder 30A. The first coil holder 60 is layered above (+z direction) the second coil holder 70. The first coil holder 60 is provided so as to be located between the second magnet holder 30A and the first magnet holder 20A. 【0063】 Therefore, compared to the configuration shown in Patent Document 1, in which four pairs of magnets are arranged on the same plane of the magnet holding part and coils corresponding to each of the aforementioned pairs of magnets are arranged on the same plane of the coil holding part, the area of ​​the xy plane can be made smaller. That is, by configuring the voice coil motor 1 by layering, the same plane (same horizontal plane, same xy plane) is responsible for the thrust force of only one axis (either the x-axis direction or the y-axis direction). As a result, compared to the case in which the same plane is responsible for the thrust force of two axes, a greater thrust force can be secured when the same amount of current with the same amount of heat is passed through the same plane. Therefore, the voice coil motor 1 of this disclosure can improve the thrust force of the voice coil motor as a whole while suppressing an increase in the horizontal size. 【0064】 In the case of arranging four pairs of magnets on the same surface of the magnet holder as shown in Patent Document 1, it was sometimes necessary to configure the device in a way that resulted in a poor balance between the movable stroke and the arrangement of the coils (magnets), for example, by positioning the coils too close to a large movable stroke. In this case, for example, a magnet for movement in the x-axis direction may react with a coil for movement in the y-axis direction, potentially generating unnecessary thrust. The voice coil motor of this disclosure avoids such problems because it is responsible for thrust in only one axis (either the x-axis or y-axis direction) on the same surface. 【0065】 An example of an embodiment of the voice coil motor of the present disclosure has been described above. In this embodiment, the magnet unit 10 was described as a moving element as a device for moving the magnet unit 10 and the coil unit 50 as a stator as a device for fixing the coil unit 50. However, the voice coil motor of the present disclosure is not limited to this, and the magnet unit 10 may be configured as a stator and the coil unit 50 as a moving element. That is, when the magnet unit 10 is the moving element, the coil unit 50 is the stator, and when the magnet unit 10 is the stator, the coil unit 50 is the moving element. Needless to say, the voice coil motor described in this embodiment can be modified as appropriate without departing from the spirit of the present disclosure. [Explanation of symbols] 【0066】 1 voice coil motor 10 magnet units 100 Voice Coil Motor System 11A First Fixing Plate 12.52 volts 2 air stage 2a Base 2aa Top surface 2ab bottom side 2a5 Bolt insertion hole 2a6 Hole 2b Stage 2b1 Mobile connector 2b2 Stage body 2b3 Stage base 2b4 Bolt insertion hole section 20A First magnet holding section 21b, 23b 1st magnet 22b, 24b 2nd magnet 29,39,49 Holding unit body 291 First side 292 Side 2 3 Encoder 3a Encoder body 3b Reflector 30A 2nd magnet holding part 31b, 33b 3rd magnet 32b,34b 4th magnet 35b,37b 5th magnet 36b,38b 6th magnet 391 3rd surface 392 4th side 39m1~39m4 Groove 40A Third magnet holding part 41b, 43b Magnet No. 7 42b, 44b Magnet No. 8 491 5th page 492 6th page 50 Coil Unit 51A, 51Aa, 51Ab Second Fixing Plate 514 Hole 60 First coil holding section 61 First coil 62,72 Joint 63, 73, 74 Cable 69, 79 Holder 691,791 Hole section 70 Second coil holding section 71 Second coil C1~C4 First direction~Fourth direction

Claims

[Claim 1] A voice coil motor having a magnet unit and a coil unit, When the magnet unit is a moving element, the coil unit is a stator, and when the magnet unit is a stator, the coil unit is a moving element. The magnet unit has a first magnet holder, a second magnet holder, and a third magnet holder, which are relatively fixed and have a hierarchical structure in a predetermined direction. The coil unit has a first coil holding section having a first coil and a second coil holding section having a second coil, which are relatively fixed and have a hierarchical structure in the predetermined direction. The first magnet holder has a first surface and a second surface opposite to the first surface, and the second surface has a first magnet of first polarity and a second magnet of second polarity, which are aligned in a first direction intersecting the predetermined direction, facing the first coil holder. The second magnet holder has a third surface and a fourth surface opposite to the third surface, the third surface has a third magnet of second polarity and a fourth magnet of first polarity aligned in the order of a first direction, facing the first coil holder, and the fourth surface has a fifth magnet of first polarity and a sixth magnet of second polarity aligned in the order of a third direction intersecting the first direction, facing the second coil holder, The third magnet holder has a fifth surface and a sixth surface opposite to the fifth surface, and on the fifth surface, there is a seventh magnet of second polarity and an eighth magnet of first polarity, which are aligned in the order of the third direction, facing the second coil holder. The first magnet holding portion, the second magnet holding portion, and the first coil holding portion cooperate to enable the movement of the moving element in the first direction and in the second direction which is the opposite direction to the first direction. The second magnet holding portion, the third magnet holding portion, and the second coil holding portion are configured to cooperate in enabling the movement of the moving element in the third direction and in the fourth direction which is the opposite direction to the third direction. Voice coil motor. [Claim 2] The first coil is a coil wound in a ring shape in the order of the first direction, the third direction, the second direction, and the fourth direction, or in the reverse order thereof. The second coil is a set of two coils wound in a ring shape in the order of the first direction, the third direction, the second direction, and the fourth direction, or in the reverse order thereof. The magnet unit and the coil unit are configured such that at least a portion of the first coil wound in the fourth direction faces the first magnet and the third magnet, respectively, with a predetermined gap between them; at least a portion of the first coil wound in the third direction faces the second magnet and the fourth magnet, respectively, with a predetermined gap between them; at least a portion of the second coil wound in the first direction faces the fifth magnet and the seventh magnet, respectively, with a predetermined gap between them; and at least a portion of the second coil wound in the second direction faces the sixth magnet and the eighth magnet, respectively, with a predetermined gap between them. The voice coil motor according to claim 1. [Claim 3] The aforementioned magnet unit is Two of the first magnets and two of the second magnets are mounted alternately in the first direction on the second surface. Two third magnets and two fourth magnets are mounted alternately in the first direction on the third surface. The fourth surface has two parallel rows in which the fifth magnet and the sixth magnet are mounted alternately in the third direction. The fifth surface has two parallel rows in which the seventh magnet and the eighth magnet are mounted alternately in the third direction. The coil unit is The first coil is provided for every four magnets, which consist of a pair of adjacent first and second magnets on the second surface, and a pair of adjacent third and fourth magnets on the third surface that face the pair of first and second magnets via the first coil holding portion. The device has one second coil for every four magnets, including a pair of adjacent fifth and sixth magnets on the fourth surface, and a pair of adjacent seventh and eighth magnets on the fifth surface that face the pair of fifth and sixth magnets via the second coil holding portion. The voice coil motor according to claim 2. [Claim 4] The voice coil motor according to claim 3, wherein each of the second coils is configured to be individually controllable. [Claim 5] The voice coil motor according to claim 4, wherein opposing magnets in adjacent rows on the fourth surface are magnets of different polarities.

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