Lens drive unit and lens barrel provided with same

Abstract

A lens drive unit (10) is provided with a four-group lens unit (26), a three-group lens unit (24), a first field part (23a), a second field part (23b), and coils (25a, 25b, 25c). The first field part (23a) is provided so as to extend over the outer peripheral side of a first lens (L1) and the outer peripheral side of a second lens (L2). The second field part (23b) is provided on the outer peripheral side of the first lens (L1). The coils (25a) are disposed at positions facing the first field part (23a) on the outer peripheral side of the first lens (L1). The coils (25b) are disposed at positions facing the second field part (23b) on the outer peripheral side of the first lens (L1). The coils (25c) are disposed at positions facing the first field part (23a) in a radial direction centered on the optical axis on the outer peripheral side of the three-group lens unit (24) so as to be arranged alongside the coils (25a) along the optical axis direction.

Description

Lens drive unit and lens barrel equipped with same

[0001] The present disclosure relates to, for example, a lens driving unit that drives a lens frame that holds a lens included in a lens barrel in an optical axis direction, and a lens barrel that includes the same.

[0002] Conventionally, linear motors capable of high-speed response have been used to move the lens frame of a lens barrel in the optical axis direction. In recent years, the size of image sensors used in imaging devices has been increasing in order to achieve higher pixel counts and improved dynamic ranges. As image sensors become larger, the lenses used in the lens barrels inevitably become larger, and the mass of the lenses also increases. Therefore, actuators that drive larger lenses are required to have a higher thrust force than conventional ones.

[0003] For example, Patent Document 1 discloses a lens drive unit comprising: n-phase coils that are movable back and forth in the optical axis direction, are fixed to a first moving frame that holds a lens, and have winding axes that are approximately perpendicular to the optical axis of the lens and are arranged side by side along the optical axis; and a first field magnet portion that has north and south poles arranged alternately along the optical axis direction and is arranged in positions facing each other radially on both sides of the n-phase coil so as to sandwich the n-phase coil in the radial direction centered on the optical axis, with the coils arranged in two or more sets side by side in the optical axis direction, with one set of n-phase coils for one first field magnet portion.

[0004] Japanese Patent Application Laid-Open No. 2023-129928

[0005] However, the above-mentioned conventional lens driving unit has the following problems: In the lens driving unit disclosed in the above publication, the moving frames that hold the lenses are each driven back and forth in the optical axis direction by a plurality of coils, which means that the number of parts is large and this may not be sufficient from the perspective of miniaturizing the lens barrel.

[0006] The object of the present disclosure is to provide a lens driving unit and a lens barrel equipped with the same that can be made smaller and lighter than conventional units in a configuration that includes multiple field magnet sections and multiple lens frame units.

[0007] (Means for Solving the Problem) A lens driving unit according to the present disclosure includes a first moving frame, a second moving frame, a first field magnet portion, a second field magnet portion, an n-phase first coil, an n-phase second coil, and an n-phase third coil. The first moving frame is movable back and forth in the optical axis direction and holds a first lens. The second moving frame is arranged alongside the first moving frame in the optical axis direction and is movable back and forth in the optical axis direction and holds a second lens. The first field magnet portion is arranged along the optical axis direction so as to straddle the outer periphery of the first lens on the first moving frame and the outer periphery of the second lens on the second moving frame, and has N poles and S poles arranged alternately along the optical axis direction. The second field magnet portion is arranged at least on the outer periphery of the first lens on the first moving frame and has N poles and S poles arranged alternately along the optical axis direction. The n-phase first coil is arranged in a position facing the first field magnet portion on the outer periphery of the first lens on the first moving frame. The n-phase second coil is arranged on the outer periphery of the first lens of the first moving frame at a position facing the second field magnet portion, and the n-phase third coil is arranged on the outer periphery of the second lens of the second moving frame at a position facing the first field magnet portion in the radial direction centered on the optical axis so as to be aligned with the first coil along the optical axis direction (where n is an integer of 2 or greater).

[0008] Effect of the Invention According to the lens driving unit according to the present disclosure, in a configuration including a plurality of field magnet portions and a plurality of lens frame units, it is possible to achieve a smaller size and lighter weight than conventional ones.

[0009] 1 is an overall perspective view showing the configuration of a camera including a lens barrel equipped with a lens driving unit according to an embodiment of the present disclosure. FIG. 1 is a perspective view showing the configuration of a lens barrel included in the camera of FIG. 1. FIG. 2 is an exploded perspective view showing each component constituting the lens barrel of FIG. 2. FIG. 3 is a perspective view showing the configuration of a third-fourth group unit included in the lens barrel of FIG. 3. FIG. 4 is an exploded perspective view showing each component constituting the third-fourth group unit of FIG. 4. FIG. 5 is a perspective view showing the configuration of a lens driving unit included in the third-fourth group unit of FIG. 5. FIG. 6 is a front view of the lens driving unit of FIG. 6. FIG. 7 is a cross-sectional view taken along line A-A of the lens driving unit of FIG. 7. FIG. 8 is a perspective view showing the configuration of a coil included in a lens driving unit according to a second embodiment of the present disclosure. FIG. 9 is an overall perspective view showing the configuration of a lens driving unit equipped with the coil of FIG. 9. FIG. 10 is a front view of the lens driving unit of FIG. 10. FIG. 11 is a cross-sectional view taken along line B-B of the lens driving unit of FIG. 11. FIG. 12 is a perspective view showing the configuration of a coil included in a lens driving unit according to a third embodiment of the present disclosure. FIG. 13 is a perspective view showing the configuration of a lens driving unit equipped with the coil of FIG. 13. FIG. 14 is a front view of the lens driving unit of FIG. 14. FIG. 15 is a cross-sectional view taken along line C-C of the lens driving unit of FIG. 15. 20 is a perspective view showing a field magnet portion and a coil having a winding axis parallel to the optical axis direction included in a lens driving unit according to a fourth embodiment of the present disclosure. 21 is a perspective view showing a configuration of a lens driving unit equipped with the field magnet portion and coil of FIG. 17. 22 is a front view of the lens driving unit of FIG. 28. 23 is a cross-sectional view of the lens driving unit of FIG. 29 along line D-D. 24 is a perspective view showing a configuration of a lens driving unit according to another embodiment of the present disclosure. 25 is an exploded perspective view showing each component constituting the lens driving unit of FIG. 29. 26 is a front view of the lens driving unit of FIG. 21. 27 is a cross-sectional view of the lens driving unit of FIG. 22 along line E-E. 28 is a perspective view showing a configuration of a lens driving unit according to yet another embodiment of the present disclosure. 29 is an exploded perspective view showing each component constituting the lens driving unit of FIG. 30. 31 is a front view of the lens driving unit of FIG. 31. 32 is a cross-sectional view of the lens driving unit of FIG. 32 along line F-F. 29 is a perspective view showing a configuration of a lens driving unit according to a fourth embodiment of the present disclosure. 33 is an exploded perspective view showing each component constituting the lens driving unit of FIG. 32. 34 is a front view of the lens driving unit of FIG. 33. 35 is a cross-sectional view of the lens driving unit of FIG. 34 along line F-F.

[0010] Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed description of already well-known matters or redundant description of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. Note that the applicant provides the accompanying drawings and the following description to enable those skilled in the art to fully understand the present disclosure, and is not intended to limit the subject matter described in the claims.

[0011] (Embodiment 1) A lens barrel 30 equipped with a lens drive unit 10 according to an embodiment of the present disclosure and a camera 50 including the same will be described below with reference to Figures 1 to 8. (1) Configuration of Camera 50 As shown in Figure 1, the camera 50 according to this embodiment is an integrated lens camera in which the lens barrel 30 and a camera body 51 are integrated, and includes the lens barrel 30, the camera body 51, and a release button 52.

[0012] The lens barrel 30 is fixed to the front of the camera body 51 on the subject side. The camera body 51 houses an image sensor 36a, which will be described later, located at the end of the lens barrel 30 opposite the subject. As shown in FIG. 1 , the release button 52 is a camera accessory located at the upper right corner of the camera body 51 and is attached to the shutter button. When the release button 52 is pressed to photograph a subject, exposure of the image sensor mounted on the camera body 51 begins.

[0013] (2) Configuration of Lens Barrel 30 As shown in Fig. 2, the lens barrel 30 according to this embodiment is configured to guide light entering from the subject side through lenses L1 to L5 (see Fig. 3) to the image sensor 36a of the image sensor unit 36. As shown in Fig. 3, the lens barrel 30 includes an operation ring unit 31, a first lens unit 32, a second lens unit 33, an aperture shutter unit 34, a third-fourth lens unit 20, a fifth lens unit 35, and an image sensor unit 36.

[0014] As shown in Fig. 2, the operation ring unit 31 is a substantially cylindrical member that forms the outer shell of the lens barrel 30, and is arranged on the outermost side of the members that form the lens barrel 30. As shown in Fig. 3, the first lens unit 32 is a substantially cylindrical member that holds the first lens L1, and is fixedly arranged on the inner side of the operation ring unit 31. The first lens unit 32 is arranged on the inner side of the operation ring unit 31, closest to the subject in the optical axis direction.

[0015] As shown in Fig. 3, the second lens unit 33 holds the second lens L2 and is fixedly disposed on the inner periphery of the first lens unit 32, which is disposed on the inner periphery of the operation ring unit 31. The second lens unit 33 also has an image stabilization unit (not shown). As shown in Fig. 3, the aperture / shutter unit 34 is disposed on the opposite side of the second lens unit 33 from the subject (image plane side) in the optical axis direction. The aperture / shutter unit 34 has an aperture function that adjusts the amount of light passing through each of the lenses L1 to L5 and a shutter function that exposes the image sensor 36a mounted on the image sensor unit 36.

[0016] 3, the third-fourth group unit 20 is disposed on the image plane side of the aperture shutter unit 34 in the optical axis direction. The third-fourth group unit 20 includes a third group lens unit 24 and a fourth group lens unit 26 that hold a third group lens L3 and a fourth group lens L4 as focus lenses. The third group lens unit 24 and the fourth group lens unit 26 are driven separately to move back and forth in the optical axis direction.

[0017] 3, the fifth lens group unit 35 is disposed between the third-fourth group unit 20 and the image sensor unit 36, and holds the fifth lens group L5. As shown in FIG. 3, the image sensor unit 36 ​​is a substantially plate-shaped member fixed inside the camera body 51, and has an image sensor 36a whose center is located on an extension of the optical axis.

[0018] (3) Configuration of the 3rd-4th Group Unit 20 As shown in FIG. 4, the 3rd-4th group unit 20 according to this embodiment has a generally cylindrical shape formed by combining a plurality of members, and includes a 3rd-group lens unit 24 that holds the 3rd-group lens L3, and a 4th-group lens unit 26 (see FIG. 5) that holds the 4th-group lens L4.

[0019] More specifically, as shown in FIG. 5, the third-fourth group unit 20 includes a third-fourth group fixed frame 21, a guide shaft 22, a first field magnet portion 23a, a second field magnet portion 23b, a third group lens unit (second moving frame) 24, a coil (first coil) 25a, a coil (second coil) 25b, a coil (third coil) 25c, a fourth group lens unit (first moving frame) 26, and a cover 27.

[0020] As shown in FIG. 5 , the third-fourth group fixing frame 21 is disposed closest to the subject among the components constituting the third-fourth group unit 20. A plurality of guide shafts 22 and the subject-side ends of the first field magnet portion 23 a and the second field magnet portion 23 b are fixed to the third-fourth group fixing frame 21. As shown in FIG. 5 , the plurality of guide shafts 22 are each disposed parallel to the optical axis, and are inserted into holes provided in the third lens group unit 24 and the fourth lens group unit 26 to guide the third lens group unit 24 and the fourth lens group unit 26 in the optical axis direction. The subject-side end of the guide shaft 22 is fixed to the third-fourth group fixing frame 21, and the image plane-side end is fixed to the cover 27.

[0021] 5, the first field magnet portion 23a is provided along the optical axis direction so as to straddle the outer periphery of the fourth lens group L4 in the fourth lens group unit 26 and the outer periphery of the third lens group L3 in the third lens group unit 24. The first field magnet portion 23a has two plate-shaped yokes 23aa and magnets 23ab provided on the opposing surfaces of the two plate-shaped yokes 23aa.

[0022] 5 and 8, the first field magnet portion 23a is disposed within the driving range in the optical axis direction of the third lens unit 24 and the fourth lens unit 26, and has a length in the optical axis direction greater than that of the second field magnet portion 23b. The magnets 23ab are configured so that north and south poles are alternately disposed along the optical axis direction.

[0023] 5, the second field magnet portion 23b is provided on the outer periphery of the fourth lens group L4 in the fourth lens group unit 26, at a position facing the first field magnet portion 23a across the optical axis. The second field magnet portion 23b has two plate-shaped yokes 23ba and magnets 23bb provided on the surfaces of the two plate-shaped yokes 23ba that face each other.

[0024] 5 and 8, the second field magnet portion 23b is disposed within the driving range in the optical axis direction of the fourth lens unit 26, and has a length in the optical axis direction that is shorter than that of the first field magnet portion 23a. The magnet 23bb is configured so that north and south poles are alternately disposed along the optical axis direction.

[0025] As shown in Fig. 5 , the third lens unit (second moving frame) 24 holds the third lens (second lens) L3 and is disposed on the subject side of the fourth lens unit 26 in the optical axis direction. The third lens unit 24 is supported in a state where it can move back and forth in the optical axis direction along the guide shaft 22. As shown in Fig. 5 , the coil (first coil) 25a is fixedly disposed in a position facing the first field magnet portion 23a on the outer periphery of the fourth lens unit 26, the fourth lens L4. The coil 25a is wound around a winding axis that is disposed in a direction substantially perpendicular to the optical axis, and two phases (two coils) are disposed as a set so as to be aligned in the optical axis direction.

[0026] Furthermore, the coil 25a is disposed in the gap between the magnets 23ab of the first field magnet portion 23a, and moves back and forth in the optical axis direction within the gap between the first field magnet portion 23a due to electromagnetic force generated by energization. This allows the fourth lens unit 26, to which the coil 25a is fixed, to move back and forth in the optical axis direction. As shown in FIG. 5 , the coil (second coil) 25b is fixedly disposed in a position facing the second field magnet portion 23b on the outer periphery of the fourth lens group L4 in the fourth lens unit 26. The coil 25b is wound around a winding axis disposed in a direction substantially perpendicular to the optical axis, and is disposed in a two-phase (two) set so as to be aligned in the optical axis direction. The coil 25b is disposed in a position facing the coil 25a in the radial direction of the fourth lens group unit 26.

[0027] Furthermore, coil 25b is disposed in the gaps between magnets 23bb of second field magnet portion 23b, and moves back and forth in the optical axis direction within the gaps of second field magnet portion 23b due to electromagnetic force generated by energization. This allows fourth lens unit 26, to which coil 25b is fixed, to move back and forth in the optical axis direction. As shown in FIG. 5 , coil (third coil) 25c is fixedly disposed on the outer periphery of third lens group L3 of third lens unit 24 at a position facing first field magnet portion 23a in the radial direction centered on the optical axis, so as to be aligned with coil 25a along the optical axis direction. Coil 25c is wound around a winding axis that is disposed in a direction substantially perpendicular to the optical axis, and two phases (two coils) are disposed as a set so as to be aligned along the optical axis direction.

[0028] Furthermore, coil 25c is disposed together with coil 25a in the gap between magnets 23ab of first field magnet portion 23a, and moves back and forth in the optical axis direction within the gap of first field magnet portion 23a by electromagnetic force generated by energization. This allows third lens unit 24, to which coil 25c is fixed, to move back and forth in the optical axis direction. Note that the two-phase coils 25a, 25b, 25c refer to a configuration in which two coils, each having an electric wire wound around a winding axis disposed in a direction perpendicular to the optical axes of third lens group L3 and fourth lens group L4, are disposed opposite each other along the optical axis direction with respect to first field magnet portion 23a and second field magnet portion 23b.

[0029] As shown in Fig. 5, the fourth lens unit (first moving frame) 26 holds a fourth lens (first lens) L4 and is disposed on the opposite side of the third lens unit 24 from the subject (image plane side) in the optical axis direction. Similar to the third lens unit 24, the fourth lens unit 26 is supported in a state in which it can move in the optical axis direction along the guide shaft 22. As shown in Fig. 5, the cover 27 is disposed on the farthest side from the subject in the optical axis direction and holds the ends of the guide shaft 22, the first field magnet portion 23a, and the second field magnet portion 23b that are opposite to the subject.

[0030] (4) Configuration of Lens Drive Unit 10 The lens drive unit 10 according to this embodiment moves the third lens unit 24 and the fourth lens unit 26 included in the third-fourth unit 20 back and forth in the optical axis direction. As shown in Figures 6 and 7, the lens drive unit 10 mainly includes the third lens unit 24, the fourth lens unit 26, a first field magnet portion 23a, a second field magnet portion 23b, and coils 25a, 25b, and 25c.

[0031] In the lens driving unit 10 of this embodiment, the fourth lens unit 26 is driven by an electromagnetic force generated by energizing the coils 25 a and 25 b, and the third lens unit 24 is driven by an electromagnetic force generated by energizing the coil 25 c. Furthermore, the first field magnet portion 23 a is disposed across the drive ranges of both the third lens unit 24 and the fourth lens unit 26, as shown in FIG.

[0032] 8, the second field magnet portion 23b is disposed at a position corresponding to the driving range of the fourth lens unit 26, which is heavier than the third lens unit 24. As a result, the heavier fourth lens unit 26 is moved back and forth in the optical axis direction by electromagnetic forces generated by energizing the coil 25a, which is disposed at a position facing the first field magnet portion 23a, and the coil 25b, which is disposed at a position facing the second field magnet portion 23b.

[0033] On the other hand, the lightweight third lens unit 24 is moved back and forth in the optical axis direction by an electromagnetic force generated by energizing only the coil 25c disposed in a position facing the first field magnet portion 23a. Therefore, compared to a configuration in which, for example, one field magnet portion is provided for the third lens unit 24 and two field magnet portions are provided for the fourth lens unit 26, the configuration can be made up of two field magnet portions (the first field magnet portion 23a and the second field magnet portion 23b), thereby achieving a smaller and lighter lens unit.

[0034] Furthermore, compared to a configuration with three field magnet sections, it is possible to avoid the increase in costs that would accompany the increased number of magnets used. Furthermore, for example, if a powerful linear motor were configured that could drive the third lens unit 24 and the fourth lens unit 26 with one field magnet section each, it would be necessary to enlarge the field magnet section, which would result in an increase in size particularly in the radial direction. However, by adopting the configuration of this embodiment, this problem can be avoided.

[0035] Furthermore, as described above, the fourth lens group unit 26 holds the fourth lens group L4, which is larger than the third lens group L3, and is therefore heavier than the third lens group unit 24. For this reason, in the lens driving unit 10 of this embodiment, the third lens group unit 24 holds a smaller third lens group L3, and is therefore lighter than the fourth lens group unit 26. As a result, the third lens group unit 24 is driven by an electromagnetic force generated by energizing only the coil 25c that is positioned opposite the first field magnet portion 23a, as shown in FIG.

[0036] On the other hand, the fourth lens unit 26 holds a fourth lens group L4 that is larger than the third lens group L3, and is therefore heavier than the third lens group 24. As a result, the fourth lens unit 26 is driven by electromagnetic forces generated by energizing coils 25a and 25b that are fixed in positions facing both the first field magnet portion 23a and the second field magnet portion 23b, as shown in FIG.

[0037] As a result, the heavy fourth lens unit 26 can be driven to move back and forth in the optical axis direction by electromagnetic forces generated at approximately opposing radial positions by energizing coils 25a and 25b. On the other hand, the light third lens unit 24 can be driven to move back and forth in the optical axis direction by power generated by energizing only coil 25c, eliminating the need for second field magnet portion 23b on the outer periphery of third lens unit 24. Therefore, by using second field magnet portion 23b, which is shorter in the optical axis direction than first field magnet portion 23a, the lens barrel 30 can be made smaller and lighter than conventional lens barrels.

[0038] <Major Features> As shown in FIG. 8 , the lens drive unit 10 of this embodiment includes a fourth lens unit 26, a third lens unit 24, a first field magnet portion 23a, a second field magnet portion 23b, an n-phase coil 25a, an n-phase coil 25b, and an n-phase coil 25c. The fourth lens unit 26 is movable back and forth in the optical axis direction and holds the fourth lens L4. The third lens unit 24 is arranged alongside the fourth lens unit 26 in the optical axis direction and is movable back and forth in the optical axis direction and holds the third lens L3. The first field magnet portion 23a is arranged along the optical axis direction so as to straddle the outer periphery of the fourth lens L4 in the fourth lens unit 26 and the outer periphery of the third lens L3 in the third lens unit 24, and has north and south poles alternately arranged along the optical axis. The second field magnet portion 23b is arranged at least on the outer periphery of the fourth lens L4 in the fourth lens unit 26 and has north and south poles alternately arranged along the optical axis direction. The n-phase coil 25a is disposed at a position facing the first field magnet portion 23a on the outer periphery of the fourth lens group L4 of the fourth lens group unit 26. The n-phase coil 25b is disposed at a position facing the second field magnet portion 23b on the outer periphery of the fourth lens group L4 of the fourth lens group unit 26. The n-phase coil 25c is disposed at a position facing the first field magnet portion 23a in the radial direction around the optical axis on the outer periphery of the third lens group L3 of the third lens group unit 24 so as to be aligned with the coil 25a along the optical axis direction (where n is an integer of 2 or greater).

[0039] That is, for example, if there is a weight difference between the third lens unit 24 and the fourth lens unit 26, only the single first field magnet portion 23a and coil 25c are arranged on the outer periphery of the lighter third lens unit 24. On the other hand, two field magnet portions (the first field magnet portion 23a and the second field magnet portion 23b) and coils 25a and 25b are arranged on the outer periphery of the heavier fourth lens unit 26.

[0040] This makes it possible to change the number of field magnet portions (first field magnet portion 23 a and second field magnet portion 23 b) arranged at positions corresponding to each unit, depending on the thrust required to drive the third lens unit 24 and the fourth lens unit 26. Furthermore, by sharing the first field magnet portion 23 a arranged to drive the third lens unit 24 and the fourth lens unit 26, the number of parts can be reduced compared to a configuration in which one field magnet portion is provided for each unit. As a result, it is possible to achieve a smaller size and lighter weight than conventional configurations while ensuring the thrust required to drive the third lens unit 24 and the fourth lens unit 26.

[0041] Second Embodiment A lens driving unit 110 according to another embodiment of the present disclosure will be described below with reference to FIGS.

[0042] The lens driving unit 110 of this embodiment uses coils 125a, 125b, and 125c, which are two-phase coils arranged in staggered positions with some of them overlapping, which differs from the configuration of the first embodiment in that the two coils are arranged side by side in the optical axis direction. For convenience of explanation, the same reference numerals are used for components having the same functions and shapes as those described in the above embodiment, and detailed explanations thereof will be omitted.

[0043] 9, the lens driving unit 110 of this embodiment includes two two-phase coils, namely, a coil (first coil) 125a, a coil (second coil) 125b, and a coil (third coil) 125c, which are arranged with a partial overlap and offset by an electrical angle of 90 degrees in the optical axis direction. In the lens driving unit 110, as shown in FIGS. 10 and 11, the coils 125a and 125c are arranged in positions facing the first field magnet portion 23a, and the coil 125b is arranged in a position facing the second field magnet portion 23b.

[0044] The coils 125a, 125b, and 125c are configured by stacking two coils that are thinner than the coils 25a, 25b, and 25c of the above embodiment, and are offset by an electrical angle of 90° in the optical axis direction so that the radial dimension does not increase. As a result, although the thrust force is weaker due to the smaller coils, the dimension in the optical axis direction can be made smaller compared to the configuration of the above embodiment 1.

[0045] That is, as shown in Fig. 12, the lens driving unit 110 of this embodiment uses coils 125a, 125b, and 125c that are arranged so that two coils partially overlap in the optical axis direction, thereby making it possible to reduce the length of the coil portions in the optical axis direction. This makes it possible to increase the driving range (stroke) of the first field magnet portion 23a and the second field magnet portion 23b. Note that the number of coils that are arranged so that they partially overlap in the optical axis direction is not limited to two, and may be three or more.

[0046] Third Embodiment A lens driving unit 210 according to still another embodiment of the present disclosure will be described below with reference to FIGS.

[0047] The lens driving unit 210 of this embodiment differs from the configuration of the first embodiment, in that it uses coils 225a, 225b, and 225c, which are two-phase coils arranged side by side in the optical axis direction, in that the portions (coil end portions) at both ends in the longitudinal direction of the coil that protrude from the field magnet portion are bent and the bent directions are opposite to each other. For convenience of explanation, the same reference numerals are used for components having the same functions and shapes as the components described in the above embodiment, and detailed explanations thereof will be omitted.

[0048] As shown in Figure 13, the lens driving unit 210 of this embodiment includes a coil (first coil) 225a, a coil (second coil) 225b, and a coil (third coil) 225c, which are assembled and arranged so that both ends of the coil in the longitudinal direction are bent and the two-phase coils partially fit into each other's winding axis so that the bending directions are opposite.

[0049] 14 and 15 , in the lens drive unit 210, the coils 225a and 225c are arranged in positions facing the first field magnet portion 23a, and the coil 225b is arranged in a position facing the second field magnet portion 23b. As described above, the coils 225a, 225b, and 225c are configured such that both ends of the coils are bent and the two phase coils are assembled so that the winding axes of the coils partially fit into each other's winding axes and the bending directions are opposite to each other.

[0050] This allows the dimension in the optical axis direction to be smaller than in the configuration of embodiment 1. Furthermore, compared to the configuration of embodiment 2, there is no need to make the coils thinner, so the dimension in the optical axis direction of the coil portion can be reduced while ensuring sufficient thrust for driving the third lens group unit 24 and the fourth lens group unit 26. That is, as shown in FIG. 16 , the lens drive unit 210 of this embodiment can reduce the length in the optical axis direction of the coil portion by using coils 225 a, 225 b, and 225 c that are arranged so that two coils are assembled together in the optical axis direction.

[0051] This allows the driving range (stroke) of the first field magnet portion 23a and the second field magnet portion 23b to be increased, and also allows the dimension of the coil portion in the optical axis direction to be reduced while ensuring sufficient thrust to drive the third lens unit 24 and the fourth lens unit 26.

[0052] Fourth Embodiment A lens driving unit 310 according to still another embodiment of the present disclosure will be described below with reference to FIGS.

[0053] The lens drive unit 310 of this embodiment differs from the configuration of the first embodiment, which uses coils 25a, 25b, 25c whose winding axes are substantially perpendicular to the optical axis direction, in that the winding axes of coils 325a, 325b, 325c fixedly disposed in the third lens unit 24 and the fourth lens unit 26 are disposed substantially parallel to the optical axis direction. For convenience of explanation, components having the same functions and shapes as those described in the above embodiments are denoted by the same reference numerals, and detailed explanations thereof will be omitted.

[0054] 17, the lens driving unit 310 of this embodiment includes covers 311a and 311b, movable rods (first field magnet portion, second field magnet portion) 323a and 323b, and coils 325a, 325b, and 325c. The movable rod (first field magnet portion) 323a is arranged along the optical axis direction, is configured so that north and south poles are alternately arranged in the optical axis direction, and is formed only from a magnet.

[0055] Movable rod (second field magnet portion) 323b is arranged along the optical axis direction, similar to movable rod 323, and is configured so that north and south poles are alternately arranged in the optical axis direction, and is formed only from a magnet. Note that, similar to first and second field magnet portions 23a and 23b in the first embodiment, movable rods 323a and 323b have their ends fixed by third-fourth group fixing frame 21 and cover 27, and their outer peripheries are covered by covers 311a and 311b.

[0056] As shown in Figures 18 and 19 , the coil (first coil) 325a is arranged so as to be wound around the outer periphery of the movable rod 323a, with its winding axis being approximately parallel to the optical axis direction. The coil 325a is fixed to the fourth lens unit 26, and moves the fourth lens unit 26 back and forth in the optical axis direction by electromagnetic force generated when current is passed through the coil 325a. The coil (second coil) 325b is arranged so as to be wound around the outer periphery of the movable rod 323b, with its winding axis being approximately parallel to the optical axis direction. The coil 325b is fixed to the fourth lens unit 26 on the opposite side of the optical axis from the coil 325a, and moves the fourth lens unit 26 back and forth in the optical axis direction by electromagnetic force generated when current is passed through the coil 325a.

[0057] 18 and 19, the coil (third coil) 325c is arranged alongside the coil 325a so as to be wound around the outer periphery of the movable rod 323a, with its winding axis being substantially parallel to the optical axis direction. The coil 325c is fixed to the third lens unit 24, and moves the third lens unit 24 back and forth in the optical axis direction by electromagnetic force generated when current is passed through the coil 325c.

[0058] 20, similarly to the first embodiment, the number of field magnet portions (movable rods 323a, 323b) arranged at positions corresponding to the third lens group unit 24 and the fourth lens group unit 26 can be changed in accordance with the thrust required to drive each unit. Also, by sharing the movable rod 323a arranged to drive the third lens group unit 24 and the fourth lens group unit 26, the number of parts can be reduced compared to a configuration in which one field magnet portion is provided for each unit.

[0059] As a result, it is possible to achieve a smaller size and lighter weight than conventional lens drive units while ensuring the thrust required to drive the third lens unit 24 and the fourth lens unit 26. In the lens drive unit 310 of this embodiment, the movable rods 323a and 323b corresponding to the first and second field magnet portions do not contain a highly magnetically permeable material such as iron, and are made only of magnets.

[0060] As a result, the movable rods 323a, 323b, which are made up only of magnets, can suppress the generation of induced currents in coils placed nearby when current is passed through one coil, compared to a configuration that includes a high-permeability material, because the permeability of magnets is generally as low as that of air.

[0061] [Other Embodiments] Although one embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment, and various modifications are possible without departing from the gist of the disclosure.

[0062] (A) In the above embodiment, an example has been described in which the lens drive unit 10 drives two lens units (the third lens unit 24 and the fourth lens unit 26) back and forth in the optical axis direction. However, the present disclosure is not limited to this. For example, as shown in FIG. 21 , a lens drive unit 410 may be configured to drive three lens units (the second lens unit (third moving frame) 433, the third lens unit 24, and the fourth lens unit 26) in the optical axis direction relative to two field magnet portions (the first field magnet portion 23 a and the second field magnet portion 423 b).

[0063] 22 and 23, the lens drive unit 410 includes a first field magnet portion 23a, a second field magnet portion 423b, a second lens unit 433, a third lens unit 24, a fourth lens unit 26, and coils 25a, 25b, 25c, and 425d. In the first field magnet portion 23a, as shown in FIG. 22, the coil 25c fixed to the third lens unit 24 and the coil 25a fixed to the fourth lens unit 26 are arranged to face each other.

[0064] On the other hand, as shown in Fig. 22, the second field magnet portion 423b has substantially the same length in the optical axis direction as the first field magnet portion 23a, and a coil (fourth coil) 425d fixedly arranged in the second lens unit 433 is arranged to face the coil 25b fixedly arranged in the fourth lens unit 26. That is, in the lens drive unit 410 of this embodiment, as shown in Fig. 24, the coil 425d is fixedly arranged in the second lens unit 433 only at a position facing the second field magnet portion 423b. Here, the second lens unit 433 is lighter than the fourth lens unit 26 because the second lens L2 is smaller than the fourth lens unit 26.

[0065] As shown in Fig. 24 , the third lens unit 24 has coil 25c fixed only at a position facing the first field magnet portion 23a. Here, the third lens unit 24 holds a third lens unit L3 that is the same size as the second lens unit L2, and therefore has the same weight as the second lens unit 433 and is lighter than the fourth lens unit 26. As shown in Fig. 24 , the fourth lens unit 26 has coils 25a and 25b fixed at positions facing both the first field magnet portion 23a and the second field magnet portion 423b, respectively. Here, the fourth lens unit 26 holds a fourth lens unit L4 that is larger than both the second lens unit 433 and the third lens unit 24, and therefore is the heaviest.

[0066] As described above, in the lens drive unit 410 of this embodiment, the second lens unit 433 and the fourth lens unit 26 share the second field magnet portion 423b, and the third lens unit 24 and the fourth lens unit 26 share the first field magnet portion 23a. This shortens the length in the optical axis direction, achieving a smaller and lighter size and weight, and avoids increased costs due to the increased number of magnets used, compared to a configuration in which the three lens units (the second lens unit 433, the third lens unit 24, and the fourth lens unit 26) each have a corresponding field magnet portion.

[0067] Furthermore, compared to a configuration in which the fourth lens unit 26, which is the heaviest, is driven by electromagnetic force generated using a single field magnet portion and coil, there is no need to generate a large thrust force with just one unit, and therefore the dimensions, particularly in the radial direction, can be made smaller. Note that the lens drive unit 410 of this embodiment may employ the configurations of the second, third, and fourth embodiments described above, instead of the coil shape and motor structure of the first embodiment.

[0068] (B) In the above embodiment (A), the lens drive unit 410 is described as an example in which three lens units (the second lens unit 433, the third lens unit 24, and the fourth lens unit 26) are combined with two field magnet portions (the first field magnet portion 23a and the second field magnet portion 423b). However, the present disclosure is not limited to this.

[0069] For example, as shown in FIG. 25 , it may be a lens driving unit 410 that drives three lens units (a second lens unit (third moving frame) 533, a third lens unit (second moving frame) 524, and a fourth lens unit (first moving frame) 526) in the optical axis direction relative to three field magnet portions (a first field magnet portion 523 a, a second field magnet portion 523 b, and a third field magnet portion 523 c).

[0070] 26 and 27, the lens drive unit 510 includes a first field magnet portion 523a, a second field magnet portion 523b, a third field magnet portion 523c, a second lens group unit 533, a third lens group unit 524, a fourth lens group unit 526, and coils 525a, 525b, 525c, 525d, 525e, and 525f. As shown in FIGS. 26 and 27, the first field magnet portion 523a, the second field magnet portion 523b, and the third field magnet portion 523c are provided along the optical axis direction, straddling the outer peripheries of the second lens group unit 533, the third lens group unit 524, and the fourth lens group unit 526, respectively.

[0071] 26 and 28, coil (first coil) 525a is fixedly disposed on the outer periphery of fourth lens unit 526 and is disposed in a position facing first field magnet portion 523a. Coil (second coil) 525b is fixedly disposed on the outer periphery of fourth lens unit 526 and is disposed in a position facing second field magnet portion 523b.

[0072] 26 and 28, coil (third coil) 525c is fixedly disposed on the outer periphery of third lens unit 524 and is disposed in a position facing first field magnet portion 523a. Coil (fourth coil) 525d is fixedly disposed on the outer periphery of second lens unit 533 and is disposed in a position facing second field magnet portion 523b.

[0073] 26 and 27, the coil (fifth coil) 525e is fixedly disposed on the outer periphery of the fourth lens unit 526 and is disposed in a position facing the third field magnet portion 523c. The coil (sixth coil) 525f is fixedly disposed on the outer periphery of the second lens unit 533 and is disposed in a position facing the third field magnet portion 523c.

[0074] 26, coils 525d and 525f are fixedly disposed on the outer periphery of second lens unit 533, and are driven back and forth in the optical axis direction by the electromagnetic force (thrust) generated between first field magnet portion 523a and third field magnet portion 523c. As shown in FIG. 26, coil 525c is fixedly disposed on the outer periphery of third lens unit 524, and is driven back and forth in the optical axis direction by the electromagnetic force (thrust) generated between first field magnet portion 523a and third field magnet portion 523c.

[0075] 26 , coils 525a, 525b, and 525e are fixedly disposed on the outer periphery of the fourth lens unit 526, and the fourth lens unit 526 is driven back and forth in the optical axis direction by electromagnetic forces (thrust forces) generated between the first field magnet portion 523a, the second field magnet portion 523b, and the third field magnet portion 523c. The second lens group L2, the third lens group L3, and the fourth lens group L4 held by each lens unit are heavier in the order of fourth lens group L4, second lens group L2, and third lens group L3. Therefore, the fourth lens group 526 is heavier than the second lens group 533, and the third lens group 524.

[0076] In the lens drive unit 510 of this embodiment, the fourth lens unit 526, which is the heaviest, is driven using three field magnet portions (first to third field magnet portions 523a to 523c), the second lens unit 533, which is the second heaviest, is driven using two field magnet portions (second field magnet portion 523b and third field magnet portion 523c), and the third lens unit 524, which is the lightest, is driven using one field magnet portion (first field magnet portion 523a). In this way, by changing and arranging the number of corresponding field magnet portions according to the thrust required for each lens unit (≒ weight of the lens unit), it is possible to achieve a reduction in size and weight while ensuring the thrust required to drive each lens unit.

[0077] (C) In the above-described first embodiment, an example has been described in which the first moving frame and the second moving frame of the present disclosure correspond to the third lens group unit 24 and the fourth lens group unit 26 included in the third-fourth lens group unit 20. However, the present disclosure is not limited to this. For example, the first moving frame and the second moving frame of the present disclosure may be configured to correspond to lens frames other than the third lens group unit and the fourth lens group unit.

[0078] (D) In ​​the above embodiment, the third lens unit 24 and the fourth lens unit 26 that hold the focus lenses (third lens unit L3 and fourth lens unit L4) have been described as examples of lens units to be driven. However, the present disclosure is not limited to this.

[0079] For example, the driving target is not limited to a focus lens unit that holds a focus lens, but may be another moving frame such as a zoom lens unit that holds a zoom lens, an image stabilization unit, or an aperture unit. If the lens held by the lens unit to be driven is a focus lens, it needs to be moved at high speed to quickly focus. On the other hand, if the lens is a zoom lens, it is preferable to move it slowly, as moving it too quickly may cause dizziness in the user.

[0080] Therefore, assuming that the thrust required to move lenses of the same weight is greater for a focus lens than for a zoom lens, the overall size and weight of the lens drive unit can be reduced by arranging the required number of field magnet sections for each lens unit according to the thrust required for each lens unit.

[0081] (E) In the above embodiment, an example was given of a configuration in which one or two lens units (third lens unit 24 and fourth lens unit 26) are combined with one field magnet portion (first and second field magnet portions 23 a, 23 b). However, the present invention is not limited to this. For example, a configuration in which three or more lens units are combined with one field magnet portion may also be used.

[0082] (F) In the above embodiment, an example was given in which the third lens unit 24 and the fourth lens unit 26 were driven back and forth in the optical axis direction using two-phase coils 25 a, 25 b, and 25 c. However, the present invention is not limited to this.

[0083] For example, as long as the lens unit is driven using an n-phase (n is an integer of 2 or greater) coil, it may be driven using a three- or more-phase coil. For example, when driving the lens unit using a three-phase coil, the coils may be arranged in groups of three in the optical axis direction for one field magnet section. However, since three-phase drive requires the coils to be arranged in groups of three in the optical axis direction, the length of each coil group in the optical axis direction tends to be longer than in the case of two-phase drive.

[0084] Furthermore, even when multiple sets of coils are arranged, the number of options for arranging the coils may be limited due to restrictions on the length in the optical axis direction. Therefore, it can be said that two-phase drive, in which two coils are arranged along the optical axis direction for one field magnet section, offers greater design freedom.

[0085] (G) In the above embodiment, the lens drive unit 10 is mounted on a lens barrel 30 that is fixed in an undetachable manner to the camera body 51. However, the present disclosure is not limited to this. For example, the configuration of the present disclosure may be applied to a lens drive unit mounted on a lens barrel that is detachably attached to the camera body.

[0086] <Supplementary Notes> The above description of the embodiments discloses the following techniques. (Technology 1) A lens driving unit according to technology 1 includes: a first moving frame movable back and forth in the optical axis direction and holding a first lens; a second moving frame arranged alongside the first moving frame in the optical axis direction and movable back and forth in the optical axis direction and holding a second lens; a first field magnet portion provided along the optical axis direction so as to straddle the outer periphery of the first lens on the first moving frame and the outer periphery of the second lens on the second moving frame, and having N poles and S poles arranged alternately along the optical axis direction; a second field magnet portion provided at least on the outer periphery of the first lens on the first moving frame, and having N poles and S poles arranged alternately along the optical axis direction; an n-phase first coil arranged at a position facing the first field magnet portion on the outer periphery of the first lens on the first moving frame; and an n-phase second coil arranged at a position facing the second field magnet portion on the outer periphery of the first lens on the first moving frame. and an n-phase third coil arranged on the outer circumferential side of the second lens of the second moving frame so as to be aligned with the first coil along the optical axis direction and to face the first field magnet portion in the radial direction centered on the optical axis (where n is an integer of 2 or more).

[0087] (Technology 2) A lens driving unit according to Technology 2 is the lens driving unit according to Technology 1, wherein the first moving frame is driven by an electromagnetic force generated by energizing the first coil and the second coil, and the second moving frame is driven by an electromagnetic force generated by energizing the third coil. (Technology 3) A lens driving unit according to Technology 3 is the lens driving unit according to Technology 1 or 2, wherein the first moving frame is heavier than the second moving frame.

[0088] (Technology 4) A lens driving unit according to Technology 4 is the lens driving unit according to any one of Technologies 1 to 3, wherein the second field magnet portion has a length in the optical axis direction that is smaller than that of the first field magnet portion. (Technology 5) A lens driving unit according to Technology 5 is the lens driving unit according to any one of Technologies 1 to 4, wherein the first coil, the second coil, and the third coil are arranged in pairs side by side in the optical axis direction at positions facing the first field magnet portion and the second field magnet portion.

[0089] (Technology 6) A lens driving unit according to Technology 6 is the lens driving unit according to any one of Technologies 1 to 5, wherein the first coil, the second coil, and the third coil each have a winding axis that is approximately perpendicular to the optical axis.

[0090] (Technology 7) A lens driving unit according to Technology 7 is the lens driving unit according to any one of Technology 1 to Technology 6, wherein the first coil, the second coil, and the third coil each have a winding axis that is approximately parallel to the optical axis.

[0091] (Technology 8) A lens driving unit according to Technology 8 is a lens driving unit according to any one of Technologies 1 to 7, further comprising: a third moving frame that is arranged alongside the first moving frame and the second moving frame in the optical axis direction, and that has a third lens and a third main body portion that is movable back and forth in the optical axis direction of the third lens and holds the third lens; and an n-phase fourth coil that is arranged on the outer periphery of the third moving frame at a position where the second field portion faces the second coil in a radial direction centered on the optical axis, so as to be alongside the second coil along the optical axis direction.

[0092] (Technology 9) A lens driving unit according to Technology 9 is a lens driving unit according to any one of Technologies 1 to 8, wherein the first coil, the second coil, and the third coil are arranged in pairs at positions facing the first field magnet portion and the second field magnet portion, with a partial overlap and shifted by an electrical angle of 90 degrees in the optical axis direction.

[0093] (Technology 10) A lens driving unit according to Technology 10 is a lens driving unit according to any one of Technologies 1 to 9, wherein the first coil, the second coil, and the third coil are arranged in pairs at positions facing the first field magnet portion and / or the second field magnet portion, and have bent portions at both ends in the longitudinal direction, and the two first coils, the second coils, and the third coils are assembled and arranged so that the bent portions face in opposite directions and that parts of the coils extend into each other's winding axes.

[0094] (Technology 11) A lens driving unit according to Technology 11 is the lens driving unit according to any one of Technologies 1 to 10, further including: a third moving frame that is arranged alongside the first moving frame and the second moving frame in the optical axis direction, is movable back and forth in the optical axis direction, and holds a third lens; and a third field magnet portion that is provided along the optical axis direction so as to straddle the outer periphery of the first lens, the second lens, and the third lens, and has north poles and south poles that are arranged alternately along the optical axis direction.

[0095] (Technology 12) A lens driving unit according to Technology 12 is the lens driving unit according to Technology 11, further comprising: an n-phase fourth coil arranged at a position facing the second field magnet portion in a radial direction centered on the optical axis on the outer periphery of the third moving frame so as to be aligned with the second coil along the optical axis direction; an n-phase fifth coil arranged at a position facing the third field magnet portion on the outer periphery of the first lens on the third moving frame; and an n-phase sixth coil arranged at a position facing the third field magnet portion in a radial direction centered on the optical axis on the outer periphery of the third moving frame so as to be aligned with the fifth coil along the optical axis direction.

[0096] (Technology 13) A lens driving unit according to Technology 13 is the lens driving unit according to Technology 12, wherein the first moving frame is driven by an electromagnetic force generated by energizing the first coil, the second coil, and the fifth coil, the second moving frame is driven by an electromagnetic force generated by energizing the third coil and the fourth coil, and the third moving frame is driven by an electromagnetic force generated by energizing the sixth coil.

[0097] (Technology 14) A lens driving unit according to Technology 14 is the lens driving unit according to Technology 13, wherein the first moving frame is heavier than the second moving frame, and the second moving frame is heavier than the third moving frame. (Technology 15) A lens barrel according to Technology 15 includes: the lens driving unit according to any one of Technologies 1 to 14; and a substantially cylindrical member that houses the lens driving unit.

[0098] The lens driving unit of the present disclosure has a configuration including multiple field magnet sections and multiple lens frame units, and has the effect of being smaller and lighter than conventional units, and is therefore widely applicable to various devices that drive optical lenses in the optical axis direction.

[0099] 10 Lens drive unit 20 3rd-4th group unit 21 3rd-4th group fixed frame 22 Guide shaft 23a First field magnet part 23aa Yoke 23ab Magnet 23b Second field magnet part 23ba Yoke 23bb Magnet 24 3rd group lens unit (second moving frame) 25a Coil (first coil) 25b Coil (second coil) 25c Coil (third coil) 26 4th group lens unit (first moving frame) 27 Cover 30 Lens barrel 31 Operation ring unit (cylindrical member) 32 1st group lens unit 33 2nd group lens unit 34 Aperture shutter unit 35 5th group lens unit 36 ​​Image sensor unit 50 Camera 51 Camera body 52 Shutter button 110 Lens drive unit 125a Coil (first coil) 125b Coil (second coil) 125c Coil (third coil) 210 Lens driving unit 225a Coil (first coil) 225b Coil (second coil) 225c Coil (third coil) 310 Lens driving unit 311a, 311b Cover 323a Movable rod (first field magnet part) 323b Movable rod (second field magnet part) 325a Coil (first coil) 325b Coil (second coil) 325c Coil (third coil) 410 Lens driving unit 423b Second field magnet part 425d Coil (fourth coil) 433 Second group lens unit (third moving frame) 510 Lens driving unit 523a First field magnet part 523b Second field magnet part 523c Third field magnet part 524 Third group lens unit (second moving frame) 525a Coil (first coil) 525b Coil (second coil) 525c Coil (third coil) 525d Coil (fourth coil) 525e Coil (fifth coil) 525f Coil (sixth coil) 526 Fourth group lens unit (first moving frame) 533 Second group lens unit (third moving frame)

Claims

1. A first moving frame movable back and forth in the optical axis direction and holding a first lens; a second moving frame disposed alongside the first moving frame in the optical axis direction and movable back and forth in the optical axis direction and holding a second lens; a first field magnet portion provided along the optical axis direction so as to straddle the outer periphery of the first lens on the first moving frame and the outer periphery of the second lens on the second moving frame, and having N poles and S poles arranged alternately along the optical axis direction; a second field magnet portion provided at least on the outer periphery of the first lens on the first moving frame, and having N poles and S poles arranged alternately along the optical axis direction; an n-phase first coil disposed at a position facing the first field magnet portion on the outer periphery of the first lens on the first moving frame; and an n-phase second coil disposed at a position facing the second field magnet portion on the outer periphery of the first lens on the first moving frame. a third coil of n phases arranged on the outer circumferential side of the second lens of the second moving frame so as to be aligned with the first coil along the optical axis direction and to face the first field magnet portion in a radial direction about the optical axis (where n is an integer of 2 or more).

2. The lens driving unit according to claim 1, wherein the first moving frame is driven by an electromagnetic force generated by energizing the first coil and the second coil, and the second moving frame is driven by an electromagnetic force generated by energizing the third coil.

3. The lens driving unit according to claim 1 or 2, wherein the first moving frame is heavier than the second moving frame.

4. The lens driving unit according to claim 1 or 2, wherein the second field magnet portion has a length in the optical axis direction that is smaller than that of the first field magnet portion.

5. A lens driving unit according to claim 1 or 2, wherein the first coil, the second coil and the third coil are arranged in pairs in the optical axis direction at positions facing the first field magnet portion and the second field magnet portion.

6. A lens driving unit according to claim 1 or 2, wherein the first coil, the second coil and the third coil each have a winding axis that is substantially perpendicular to the optical axis.

7. The lens driving unit according to claim 1 or 2, wherein the first coil, the second coil and the third coil each have a winding axis that is substantially parallel to the optical axis.

8. A lens driving unit as described in claim 1 or 2, further comprising: a third moving frame arranged alongside the first moving frame and the second moving frame in the optical axis direction, the third moving frame having a third lens and a third main body portion that is movable back and forth in the optical axis direction of the third lens and holds the third lens; and an n-phase fourth coil arranged on the outer periphery of the third moving frame in a position facing the second field portion in a radial direction centered on the optical axis so as to be aligned with the second coil along the optical axis direction.

9. A lens driving unit as described in claim 1 or 2, wherein the first coil, the second coil and the third coil are arranged in pairs at positions facing the first field magnet portion and the second field magnet portion, with a partial overlap and offset by an electrical angle of 90 degrees in the optical axis direction.

10. A lens driving unit as described in claim 1 or 2, wherein the first coil, the second coil and the third coil are arranged in pairs at positions facing the first field magnet portion and / or the second field magnet portion, and have bent portions at both ends in the longitudinal direction, and the two first coils, the second coils and the third coils are assembled and arranged so that the bent portions face in opposite directions and that part of each coil extends into the other's winding axis.

11. A lens driving unit as described in claim 1, further comprising: a third moving frame that is arranged alongside the first moving frame and the second moving frame in the optical axis direction, is movable back and forth in the optical axis direction, and holds a third lens; and a third field magnet portion that is provided along the optical axis direction so as to straddle the outer periphery of the first lens, the second lens, and the third lens, and has north and south poles that are arranged alternately along the optical axis direction.

12. A lens driving unit as described in claim 11, further comprising: an n-phase fourth coil arranged on the outer periphery of the third moving frame at a position opposite the second field magnet portion in a radial direction centered on the optical axis so as to be aligned with the second coil along the optical axis direction; an n-phase fifth coil arranged on the outer periphery of the first lens on the first moving frame at a position opposite the third field magnet portion in a radial direction centered on the optical axis so as to be aligned with the fifth coil along the optical axis direction; 13. A lens driving unit as described in claim 12, wherein the first moving frame is driven by an electromagnetic force generated by energizing the first coil, the second coil, and the fifth coil, the second moving frame is driven by an electromagnetic force generated by energizing the third coil and the fourth coil, and the third moving frame is driven by an electromagnetic force generated by energizing the sixth coil.

14. The lens driving unit according to claim 13, wherein the first moving frame is heavier than the second moving frame, and the second moving frame is heavier than the third moving frame.

15. A lens barrel comprising: a lens driving unit according to claim 1 or 2; and a substantially cylindrical member containing the lens driving unit.

Images