Lens driving device and lens barrel equipped with same

Abstract

A lens driving device (10) comprises a five-group unit (20), a field unit (33a), n-phase coils (25a), insertion support parts (31da, 37ba), and a spacer (34e). The field unit (33a) has magnets that are alternately disposed along the optical axis direction such that the N poles and S poles are alternately disposed. The n-phase coils (25a) are disposed in the five-group unit (20) at positions close to the field unit (33a), have a winding axis oriented in a direction substantially orthogonal to the optical axis, and are disposed side by side along the optical axis direction. The insertion support parts (31da, 37ba) support both ends of the field unit (33a) in the optical axis direction. The spacer (34e) supports the field unit (33a) at an intermediate position of the field unit (33a) and suppresses warping of the field unit (33a).

Description

Lens driving device and lens barrel including the same

[0001] The present disclosure relates to a lens driving device that drives a moving frame holding a lens in an optical axis direction, and to a lens barrel including 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. For example, Patent Document 1 discloses a magnetic circuit unit including a first magnet, a second magnet, a first yoke holding the first magnet and the second magnet, and a second yoke disposed between the first magnet and the second magnet. The driving device includes a first coil coupled to a first zoom lens and corresponding to the first magnet, and a second coil coupled to a second zoom lens and corresponding to the second magnet, wherein the magnetic circuit unit drives the first coil and the second coil, and a thickness of the second yoke is larger than a thickness of the first yoke.

[0003] Japanese Unexamined Patent Publication No. 2023-141533

[0004] However, the above-described conventional driving device has the following problems. That is, in the driving device disclosed in the above publication, for example, when an increase in zoom magnification increases the moving amount of the moving frame in the optical axis direction, and lengthens the field portion formed by the magnet and the yoke, warpage occurs due to magnetic attraction force, which may reduce the gap between the field portions through which the coil passes.

[0005] The object of this disclosure is to provide a lens drive device and a lens barrel equipped therewith that can effectively prevent the occurrence of warping of the field section. (Means for solving the problem) The lens drive device according to this disclosure comprises a movable frame, a first field section, an n-phase coil, end-end support sections, and a warping suppression section. The movable frame is movable in the optical axis direction and holds the lens. The first field section has magnets with alternating N poles and S poles arranged along the optical axis direction. The n-phase coil is positioned in the movable frame close to the first field section, has a winding axis in a direction substantially perpendicular to the optical axis of the lens, and is arranged in a row along the optical axis direction. The end-end support sections support both ends of the first field section in the optical axis direction. The warping suppression section supports the first field section at an intermediate position in the first field section and suppresses warping of the first field section. (Effects of the invention) According to the lens drive device according to this disclosure, the occurrence of warping of the field section can be effectively prevented.

[0006] Figure 1 shows an overall perspective view of a video camera equipped with a lens drive device and lens barrel according to one embodiment of the present disclosure. Figure 1 shows an overall perspective view of the lens barrel included in the video camera. Figure 2 shows an exploded perspective view of the lens barrel. Figure 3 shows a front view of the configuration of a 1-group unit included in the lens barrel. Figure 4A shows a cross-sectional view along line E-E. Figure 3 shows a partial cross-sectional perspective view of the field unit constituting the lens drive device included in the lens barrel. Figure 3 shows an exploded perspective view of the 3-group unit included in the lens barrel. Figure 3 shows an exploded perspective view of the 4-group unit constituting the lens drive device included in the lens barrel. Figure 3 shows an exploded perspective view of the 5-group unit constituting the lens drive device included in the lens barrel. Figure 3 shows an exploded perspective view of the 6-group unit constituting the lens drive device included in the lens barrel. Figure 3 shows an exploded perspective view of the 7-group unit constituting the lens drive device included in the lens barrel. Figure 2 shows a front view of the lens barrel as seen from the subject side in the optical axis direction. Figure 11A shows a cross-sectional view along line A-A. Figure 2 shows a side cross-sectional view of the lens barrel. Enlarged view of part B in Figure 12. Enlarged view of part C in Figure 12. Enlarged view of part D in Figure 12. Diagram showing the amount of curvature of the field section in the configuration of a comparative example without a curvature suppression part (supported only at both ends). Diagram showing the amount of curvature of the field section in the configuration of a comparative example in which the field section is divided into two parts in the longitudinal direction and each end is supported. Diagram showing the amount of curvature of the configuration in which the field section included in the lens drive device of this disclosure is supported at both ends and near the center. Diagram showing the amount of curvature of the field section in the configuration of a comparative example in which the field section is divided into two parts in the left third and each end is supported. Diagram showing the amount of curvature of the configuration in which the field section included in the lens drive device of this disclosure is supported at both ends and near the left one-third position. Diagram showing the amount of curvature of the field section in the configuration of a comparative example in which the field section is divided into two parts in the left quarter section and each end is supported. Diagram showing the amount of curvature of the configuration in which the field section included in the lens drive device of this disclosure is supported at both ends and near the left one-quarter position. A front view of a lens barrel according to another embodiment of the present disclosure, as seen from the subject side in the optical axis direction. A cross-sectional view along the line F-F in Figure 15A. A perspective view showing the configuration of the field section included in the lens drive device of Figure 15A. A front view of a lens barrel equipped with the lens drive device including the field section of Figure 16, as seen from the subject side in the optical axis direction. A cross-sectional view along the line G-G in Figure 17A, showing the positional relationship between the two-group unit and the field section.A graph showing the relationship between coil position and thrust in the configuration shown in Figure 17B.

[0007] The embodiments will be described in detail below, with reference to the drawings as appropriate. However, unnecessary details may be omitted. For example, detailed explanations of already well-known matters or redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding by those skilled in the art. The applicant provides the accompanying drawings and the following explanation so that those skilled in the art can fully understand this disclosure, and not to limit the subject matter described in the claims.

[0008] (Embodiment 1) The lens drive device 10 and the lens barrel 30 equipped therewith, and the video camera (imaging device) 50 according to one embodiment of the present disclosure will be described below with reference to Figures 1 to 14G. (1) Configuration of the video camera 50 The video camera (imaging device) 50 according to this embodiment comprises a lens barrel 30, a camera body 51, and a lens hood 52, as shown in Figure 1.

[0009] The lens barrel 30 is located on the subject side of the camera body 51. The camera body 51 contains an image sensor located at the end of the lens barrel 30 opposite to the subject, which will be described later. The lens hood 52 is attached to the subject side of the lens barrel 30 to eliminate unwanted light entering the lens.

[0010] When the video camera 50 is ready to film a subject, the start shooting button is pressed, which starts exposure to the image sensor mounted on the camera body 51, and the video or image of the subject is recorded on a recording medium or the like. (2) Configuration of the lens barrel 30 As shown in Figure 2, the lens barrel 30 according to this embodiment is configured to guide the light incident from the subject side to the image sensor 39a (see Figure 3) of the image sensor unit 39 via the lens L1, etc.

[0011] As shown in Figure 3, the lens barrel 30 comprises a first group unit (cylindrical member) 31, a second group unit (movable frame) 32, field units (first field section, second field section) 33a, 33b, field units (first field section, second field section) 33c, 33d, a third group unit (fixed frame) 34, a fourth group unit (movable frame) 35, a fifth group unit (movable frame) 20, a sixth group unit (movable frame) 36, a seventh group unit 37, an IR (Infrared) unit 38, and an image sensor unit 39.

[0012] The first group unit (cylindrical member) 31 holds the lens L1 and, as a fixed member, is positioned closest to the subject in the optical axis direction. As shown in Figure 3, the subject-side ends of the two guide shafts 31a and 31b are fixed to the first group unit 31. The first group unit 31 also has, as shown in Figure 3, a substantially cylindrical main body 31c and insertion support parts (both end support parts, support openings) 31da, 31db (see Figure 4B) that support the convex end parts 33ac, 33bc, 33cc, 33dc on the subject side in the optical axis direction of the field units 33a, 33b, 33c, 33d, which will be described later.

[0013] As shown in Figures 4A and 4B, the insertion support portions 31da and 31db are provided on the side of the substantially cylindrical main body portion 31c opposite to the subject in the optical axis direction. As shown in Figure 4B, the insertion support portion 31da is a portion of the outer circumferential surface of the substantially cylindrical main body portion 31c that is recessed radially inward, and the convex ends 33ac and 33cc (see Figure 5) of the field units 33a and 33c engage with it. As a result, one end of the field units 33a and 33c on the subject side in the optical axis direction is supported by the group unit 31 (insertion support portion 31da).

[0014] As shown in Figure 4B, the insertion support portion 31db is a recessed portion on the end face of the substantially cylindrical main body portion 31c opposite to the subject in the optical axis direction, where the convex ends 33bc and 33d (see Figure 5) of the field units 33b and 33d engage. As a result, one end of the field units 33b and 33d on the subject side in the optical axis direction is supported by the group unit 31 (insertion support portion 31db).

[0015] The support structure for the field units 33a, 33b, 33c, and 33d will be described in detail later. The two guide axes 31a and 31b are arranged along the optical axis direction, as shown in Figure 3, and guide the movement of the movable member (group 2 unit 32), which will be described later, in the optical axis direction. The group 2 unit (moving frame) 32 holds the lens L2 and is arranged to be movable back and forth in the optical axis direction. As shown in Figure 3, when current is applied to the two-phase coils 32a and 32b, which are arranged above and below the optical axis, the group 2 unit 32 moves in the optical axis direction due to the Lorentz force (electromagnetic force) generated between it and the field units 33a, 33b and field units 33c, 33d, which will be described later.

[0016] The field units (first field section, second field section) 33a, 33b and field units 33c, 33d (first field section, second field section) together with coils 25a, 25b, etc., provided on a movable frame such as the 5-group unit 20 described later, constitute the lens drive device 10. The field units 33a, 33b, 33c, and 33d are arranged with their longitudinal direction aligned with the optical axis. The field units 33a, 33b, 33c, and 33d are arranged in close proximity to each other with a predetermined gap between them, and a coil 25a or coil 25b passes through the predetermined gap. The field units 33a, 33b and the field units 33c, 33d are arranged to sandwich the optical axis in the radial direction centered on the optical axis.

[0017] As shown in Figure 5, the field unit (first field section) 33a includes a magnet 33aa with alternating N poles and S poles in the optical axis direction, a plate-shaped yoke 33ab positioned radially outward from the optical axis so as to contact the magnet 33aa, and convex ends 33ac and 33ad provided at both ends of the yoke 33ab. The field unit (second field section) 33b is positioned opposite to the field unit 33a at a close distance radially inward. As shown in Figure 5, the field unit 33b includes a magnet 33ba with alternating N poles and S poles in the optical axis direction, a plate-shaped yoke 33bb positioned radially inward from the optical axis so as to contact the magnet 33ba, and convex ends 33bc and 33bd provided at both ends of the yoke 33bb.

[0018] As shown in Figure 5, the magnets 33aa and 33ba are connected with their north poles and south poles alternately arranged along the optical axis, and are positioned facing each other with a predetermined gap between them. Magnets approximately half the width of the other are attached to both ends of the magnets 33aa and 33ba in the optical axis direction. The field unit (first field section) 33c, as shown in Figure 5, has a magnet 33ca with its north poles and south poles alternately arranged along the optical axis, a plate-shaped yoke 33cb positioned radially outward from the optical axis so as to contact the magnet 33ca, and convex ends 33cc and 33cd provided at both ends of the yoke 33cb.

[0019] The field unit (second field section) 33d is positioned opposite the field unit 33c at a close proximity on the radially inward side. As shown in Figure 5, the field unit 33d includes a magnet 33da with alternating north and south poles in the optical axis direction, a plate-shaped yoke 33db positioned to contact the magnet 33da on the radially inward side centered on the optical axis, and convex ends 33dc and 33dd provided at both ends of the yoke 33db.

[0020] As shown in Figure 5, magnets 33ca and 33da are connected with their north and south poles alternately arranged along the optical axis, and are positioned facing each other with a predetermined gap between them. Magnets approximately half the width of the other are attached to both ends of magnets 33ca and 33da in the optical axis direction. Note that in Figure 5, for the sake of explanation, a partial cross-section of the field units 33a, 33b, 33c, and 33d on the subject side is shown with a portion cut out, but in reality, they have the same configuration on the opposite side from the subject.

[0021] The three-group unit (fixed frame) 34 is a substantially cylindrical member and is positioned as a fixed-side member. As shown in Figure 6, the three-group unit 34 has a substantially cylindrical main body 34a, two guide shafts 34ba and 34bb, an aperture unit 34c, an insertion hole (opening) 34d, and a spacer 34e. The substantially cylindrical main body 34a has a lens holding portion 34aa that holds the lens L3 which is arranged along the optical axis.

[0022] As shown in Figure 6, the two guide axes 34ba and 34bb are provided on the inner circumferential surface side of the main body 34a. The guide axes 34ba and 34bb are provided as guides for the movement of the 4-group unit 35, 5-group unit 20, and 6-group unit 36, which will be described later, back and forth in the optical axis direction. As shown in Figure 6, the aperture unit 34c is attached to the subject-side end face of the substantially cylindrical main body 34a and adjusts the amount of light incident through the lens L3.

[0023] The insertion holes (openings) 34d are openings provided on the end face of the substantially cylindrical main body portion 34a to which the aperture unit 34c is attached, and are formed at positions facing each other on the radially outer side of the aperture unit 34c, sandwiching the optical axis. The insertion holes 34d are into which the field units 33b and 33d, which are arranged radially inward, are inserted.

[0024] The spacers (warping suppression parts) 34e are plate-shaped members arranged radially outward from the insertion holes 34d in the main body 34a, and are positioned along a direction perpendicular to the optical axis. The spacers 34e support the field units 33b and 33d on their radially inward surface (the surface facing the insertion hole 34d), and support the field units 33a and 33c on their radially outward surface.

[0025] Specifically, the spacers 34e are positioned in the gaps between field units 33a and 33b, which are located in close proximity in the radial direction, and in the gaps between field units 33c and 33d. The support structure for field units 33a, 33b, 33c, and 33d will be described in detail later.

[0026] As shown in Figure 3, the 4-group unit (movable frame) 35 is positioned on the inner circumferential surface side of the substantially cylindrical 3-group unit 34 so as to be movable back and forth in the optical axis direction. As shown in Figure 7, the 4-group unit 35 has a main body portion 35a, a lens holding portion 35b that holds the lens L4, a guide hole 35c into which the guide shaft 34ba provided on the inner circumferential surface side of the 3-group unit 34 is inserted, a coil mounting portion 35d, and a coil 35e.

[0027] Furthermore, the 4-group unit 35 is cantilevered so that it moves back and forth in the optical axis direction by energizing a 2-phase coil 35e located only on the lower side in the figure on the radially outer side of the optical axis. The 5-group unit (moving frame) 20 is configured to include an image stabilization unit (OIS (Optical Image Stabilization)) and, similar to the 4-group unit 35, is arranged on the inner circumferential surface side of the substantially cylindrical 3-group unit 34 in a state that allows it to move back and forth in the optical axis direction. As shown in Figure 8, the 5-group unit 20 includes an OIS yoke 21, OIS magnets 22a, 22b, OIS drive magnets 23a, 23b, a 5-group frame 24, coils 25a, 25b, an OIS ball 26a, an OIS biasing spring 26b, Hall elements 26ca, 26cb, OIS coils 27a, 27b, an OIS frame 28, and a cover 29.

[0028] As shown in Figure 8, the OIS yoke 21 is a substantially annular plate-shaped member and is positioned furthest towards the subject in the optical axis direction among the members constituting the 5-group unit 20. The OIS yoke 21 is positioned in close proximity to the OIS magnets 22a, 22b and the OIS drive magnets 23a, 23b. The OIS magnets 22a, 22b are positioned between the subject-side surface of the 5-group frame 24 and the OIS yoke 21.

[0029] The OIS drive magnets 23a and 23b are positioned between the subject-facing surface of the 5-group frame 24 and the OIS yoke 21, sandwiching the 5-group frame 24 in the optical axis direction, and facing the OIS coils 27a and 27b, which will be described later. As a result, the 5-group frame 24 to which the OIS drive magnets 23a and 23b are attached can be moved in a plane perpendicular to the optical axis by receiving the Lorentz force (electromagnetic force) generated when the OIS coils 27a and 27b are energized.

[0030] The 5-group frame 24 holds the lens L5 shown in Figure 8 and is positioned to be movable on a plane perpendicular to the optical axis relative to the OIS frame 28. The 5-group frame 24 moves back and forth in the optical axis direction by receiving the Lorentz force (electromagnetic force) generated between it and the field units 33a, 33b and 33c, 33d when current is passed through the coils 25a and 25b located above and below it.

[0031] Coil 25a has a winding axis arranged in a direction substantially perpendicular to the optical axis and is positioned opposite the field units 33a and 33b in the 5-group unit 20. As shown in Figure 6, coil 25a is attached to the upper side of the 5-group frame 24 and, when energized, receives the Lorentz force (electromagnetic force) generated between it and the aforementioned field units 33a and 33b. Coil 25b has a winding axis arranged in a direction substantially perpendicular to the optical axis and is positioned opposite the field units 33c and 33d in the 5-group unit 20. Furthermore, coil 25b is positioned offset from coil 25a in the optical axis direction in the 5-group unit 20. In addition, as shown in Figure 8, coil 25b is attached to the lower side of the 5-group frame 24 and, when energized, receives the Lorentz force (electromagnetic force) generated between it and the aforementioned field units 33c and 33d.

[0032] As a result, the 5-group frame 24 moves back and forth in the optical axis direction due to the Lorentz force (electromagnetic force) generated between it and the field units 33a, 33b and 33c, 33d when coils 25a and 25b are energized. As shown in Figure 8, the OIS ball 26a is positioned so as to be sandwiched between the subject-side surface of the OIS frame 28 and the opposing surface of the 5-group frame 24, and rolls on the opposing surface of the 5-group frame 24.

[0033] As shown in Figure 8, the OIS biasing spring 26b is positioned between the subject-facing surface of the OIS frame 28 and the opposing surface of the 5-group frame 24. The OIS biasing spring 26b applies a biasing force in the optical axis direction, pulling the 5-group frame 24 towards the OIS frame 28. The Hall elements 26ca and 26cb are provided as position sensors together with the OIS magnets 22a and 22b, and detect the position of the 5-group frame 24 on a plane perpendicular to the optical axis relative to the OIS frame 28.

[0034] As shown in Figure 8, the OIS coils 27a and 27b are attached to the OIS frame 28, and when energized, they generate a Lorentz force (electromagnetic force) between them and the OIS drive magnets 23a and 23b. As a result, the Lorentz force (electromagnetic force) generated when the OIS coils 27a and 27b are energized allows the 5-group frame 24 to which the OIS drive magnets 23a and 23b are attached to be moved in a plane perpendicular to the optical axis.

[0035] As shown in Figure 8, the OIS frame 28 is a substantially annular plate-shaped member to which OIS coils 27a, 27b, Hall elements 26ca, 26cb, etc. are attached. As shown in Figure 8, the cover 29 is a substantially annular plate-shaped member and is positioned on the side furthest from the subject in the optical axis direction among the members constituting the 5-group frame 24. The 6-group unit (movable frame) 36 includes a focus lens (lens L6) and, as shown in Figure 3, is positioned on the inner circumferential surface side of the substantially cylindrical 3-group unit 34 in a state that allows it to move back and forth in the optical axis direction. As shown in Figure 9, the 6-group unit 36 ​​has a main body portion 36a, a lens holding portion 36b that holds the lens L6, a guide hole 36c into which the guide shaft 34bb (see Figure 6) is inserted, a coil mounting portion 36d, and a coil 36e.

[0036] When current is supplied to the two-phase coil 36e, which is arranged along the optical axis direction on the coil mounting portion 36d of the main body portion 36a, the 6-group unit 36 ​​moves in the optical axis direction due to the Lorentz force (electromagnetic force) generated between the coil 36e and the field units 33a and 33b, which are arranged adjacent to the radially outer side of the coil 36e. Furthermore, the 6-group unit 36 ​​is cantilevered so that it moves back and forth in the optical axis direction when current is supplied to the two-phase coil 36e, which is arranged only on the upper side in the figure on the radially outer side of the optical axis.

[0037] As shown in Figure 10, the 7-group unit 37 includes a focusing lens (lens L7) and is positioned as a fixed-side component. The 7-group unit 37 has a roughly disc-shaped main body 37a, insertion support parts (end support parts, support openings) 37ba, 37bb, and screws 37c. The roughly disc-shaped main body 37a holds the lens L7 at its central portion.

[0038] As shown in Figure 10, the insertion support portion (end support portion, support opening) 37ba, 37bb is provided on the surface of the subject in the optical axis direction of the substantially disc-shaped main body portion 37a. As shown in Figure 10, the insertion support portion 37ba is a portion recessed radially inward on the outer peripheral surface of the substantially disc-shaped main body portion 37a, and supports one end of the field units 33a, 33c opposite to the subject in the optical axis direction when the convex ends 33ad, 33cd of the field units 33a, 33c are engaged with it.

[0039] As shown in Figure 10, the insertion support portion 37bb is the portion of the substantially disc-shaped main body portion 37a that is recessed toward the subject in the optical axis direction, and supports one end of the field units 33b and 33d opposite to the subject in the optical axis direction, with the convex ends 33bd and 33dd of the field units 33b and 33d engaged. The support structure of the field units 33a, 33b, 33c, and 33d will be described in detail later.

[0040] The screw 37c is screwed into a screw hole provided on the end face of the 3-group unit 34, thereby fixing the 7-group unit 37 to the 3-group unit 34. The IR unit 38 includes a mechanism for inserting and removing infrared cut glass and is positioned between the 7-group unit 37 and the image sensor unit 39. As shown in Figure 3, the image sensor unit 39 is a substantially plate-shaped member fixed inside the camera body 51 and has an image sensor 39a whose center is positioned on the extension of the optical axis.

[0041] (3) Overall configuration of the lens driving device 10 The lens driving device 10 according to this embodiment moves the above-mentioned 2-group unit 32, 4-group unit 35, 5-group unit 20 and 6-group unit 36 ​​back and forth in the optical axis direction. The lens driving device 10 includes the 2-group unit 32, 4-group unit 35, 5-group unit 20 and 6-group unit 36 ​​provided as movable moving frames, field units 33a, 33b and 33c, 33d, coils 32a, 32b, coil 35e, coils 25a, 25b and coil 36e.

[0042] When the coils 32a and 32b are energized, the second group unit 32 moves back and forth in the optical axis direction by Lorentz force (electromagnetic force) generated between the field units 33a and 33b and the field units 33c and 33d. When the coil 35e is energized, the fourth group unit 35 moves back and forth in the optical axis direction by Lorentz force (electromagnetic force) generated between the fourth group unit 35 and the field units 33c and 33d.

[0043] When the coils 25a and 25b are energized, the fifth group unit 20 moves back and forth in the optical axis direction by Lorentz force (electromagnetic force) generated between the field units 33a and 33b and the field units 33c and 33d. When the coil 36e is energized, the sixth group unit 36 moves back and forth in the optical axis direction by Lorentz force (electromagnetic force) generated between the sixth group unit 36 and the field units 33a and 33b.

[0044] As shown in FIG. 3, the field units 33a and 33b are arranged along the optical axis direction with a predetermined gap therebetween so as to sandwich the coil 32a provided on the second group unit 32, the coil 25a provided on the fifth group unit 20, and the coil 36e provided on the sixth group unit 36. As shown in FIG. 3, the field units 33c and 33d are arranged along the optical axis direction with a predetermined gap therebetween so as to sandwich the coil 32b provided on the second group unit 32, the coil 35e provided on the fourth group unit 35, and the coil 25b provided on the fifth group unit 20.

[0045] The coil 32a has a winding axis arranged along a direction substantially perpendicular to the optical axis, and is arranged between the field units 33a and 33b corresponding to the movable range of the second group unit 32. The coil 32b has a winding axis arranged along a direction substantially perpendicular to the optical axis, and is arranged between the field units 33c and 33d corresponding to the movable range of the second group unit 32. The coil 35e has a winding axis arranged along a direction substantially perpendicular to the optical axis, and is arranged between the field units 33c and 33d corresponding to the movable range of the fourth group unit 35.

[0046] The coil 25a has a winding axis arranged along a direction substantially orthogonal to the optical axis, and is arranged between the field units 33a and 33b corresponding to the movable range of the fifth-group unit 20. The coil 25b has a winding axis arranged along a direction substantially orthogonal to the optical axis, and is arranged between the field units 33c and 33d corresponding to the movable range of the fifth-group unit 20. Further, the coil 25b is arranged at a position shifted (different position) from the coil 25a in the optical axis direction of the fifth-group unit 20.

[0047] The coil 36e has a winding axis arranged along a direction substantially orthogonal to the optical axis, and is arranged between the field units 33a and 33b corresponding to the movable range of the sixth-group unit 36. <Support Structure of Field Unit> In the lens driving device 10 of the present embodiment, as shown in FIGS. 11A and 11B, the field units 33a, 33b and the field units 33c, 33d are arranged along the optical axis direction from the first-group unit 31 to the seventh-group unit 37.

[0048] The field units 33a and 33b arranged on the upper side in the figure are arranged with a predetermined gap therebetween in the radial direction centered on the optical axis. In the gap of the field units 33a and 33b, the coil 32a of the second-group unit 32, the coil 25a of the fifth-group unit 20, and the coil 36e of the sixth-group unit 36 arranged in the gap move back and forth in the optical axis direction. The field units 33c and 33d arranged on the lower side in the figure are arranged with a predetermined gap therebetween in the radial direction centered on the optical axis, similarly to the field units 33a and 33b. In the gap of the field units 33c and 33d, the coil 32b of the second-group unit 32, the coil 35e of the fourth-group unit 35, and the coil 25b of the fifth-group unit 20 arranged in the gap move back and forth in the optical axis direction.

[0049] Then, the object-side end portions of the field units 33a and 33b in the optical axis direction are supported by the first-group unit 31 at portion B in FIG. 12. More specifically, at the object-side end portion of the field unit 33a in the optical axis direction, as shown in FIG. 13A, the end portion 33ac of the yoke 33ab is supported on the radially outer surface of the insertion support portion 31da of the main body portion 31c of the first-group unit 31.

[0050] At the subject-side end of the field unit 33b in the optical axis direction, as shown in Figure 13A, the end 33bc of the yoke 33bb is supported by being inserted into the groove of the insertion support portion 31db of the main body portion 31c of the group unit 31. The subject-side ends of the field units 33c and 33d, which are located on the lower side in the figure, are supported in the optical axis direction in a similar manner.

[0051] On the other hand, the ends of the field units 33a and 33b opposite to the subject in the optical axis direction are supported by the 7-group unit 37 in portion D of Figure 12. More specifically, at the end of the field unit 33a opposite to the subject in the optical axis direction, as shown in Figure 13C, the end 33ad of the yoke 33ab is supported by being inserted into the insertion support portion 37ba of the main body portion 37a of the 7-group unit 37.

[0052] Furthermore, at the end of the field unit 33b opposite to the subject in the optical axis direction, as shown in Figure 13C, the end 33bd of the yoke 33bb is supported by being inserted into the groove of the insertion support portion 37bb of the main body portion 37a of the 7-group unit 37. The ends of the field units 33c and 33d, located at the bottom of the figure, opposite to the subject in the optical axis direction are similarly supported.

[0053] The intermediate positions of the field units 33a and 33b in the longitudinal direction are supported by the 3-group unit 34 in portion C of Figure 12. More specifically, near the intermediate position of the field unit 33a in the optical axis direction, the intermediate position of the yoke 33ab is supported by the spacer 34e of the 3-group unit 34, as shown in Figure 13B.

[0054] Similarly, near the intermediate position of the field unit 33b in the optical axis direction, as shown in Figure 13B, the intermediate position of the yoke 33bb is supported by being inserted into the insertion hole 34d of the 3-group unit 34. The intermediate positions of the field units 33c and 33d, located on the lower side in the figure, are also similarly supported by the spacer 34e and the insertion hole 34d.

[0055] As a result, even if the magnetic attraction force between field units 33a and 33b, which are positioned opposite each other in close proximity, causes them to deform in a direction toward each other, the spacer 34e placed in the gap between them can suppress the deformation of field units 33a and 33b. Similarly, even if the magnetic attraction force between field units 33c and 33d, which are positioned opposite each other in close proximity, causes them to deform in a direction toward each other, the spacer 34e placed in the gap between them can suppress the deformation of field units 33c and 33d.

[0056] Here, the results of verifying the deformation amount of the field unit in the configuration of the lens drive device 10 of this embodiment (support structure with spacer 34e) and the configuration of a comparative example in which spacer 34e is not provided are shown below. For example, as shown in Figure 14A, in the configuration of the comparative example in which spacer is not provided, there is nothing to support the field units 33a, 33b and the field units 33c, 33d, and they are supported only at both ends. For example, the amount of curvature of the field units 33a, 33c, which are arranged radially outward, is set to 1 as the reference for comparison.

[0057] Next, as shown in Figure 14B, in the comparative example configuration in which the yoke is divided into two parts and both ends are supported, and no spacer is provided, the amount of curvature of the field unit was 0.24 times because the length of the supported yoke was shortened due to the yoke being divided into two parts and both ends being supported. Next, as shown in Figure 14C, in the configuration of this embodiment (with a spacer 34e in the middle position), the amount of curvature of the field unit was 0.17 times because it is supported by the spacer 34e in the middle position.

[0058] Next, as shown in Figure 14D, in the comparative example configuration where the yoke is divided into two parts at a position 1 / 3 from the left and both ends are supported, and no spacer is provided, the amount of warping of the field unit was 0.43 times. Next, as shown in Figure 14E, in the configuration of this embodiment (with a spacer 34e at the midpoint of 1 / 3 from the left), the amount of warping of the field unit was 0.3 times because it is supported by the spacer 34e at the midpoint slightly to the left.

[0059] Next, as shown in Figure 14F, in the comparative example configuration where the yoke is divided into two parts at a 1 / 4 position from the left and both ends are supported, and no spacer is provided, the amount of warping of the field unit was 0.55 times. Next, as shown in Figure 14G, in the configuration of this embodiment (with a spacer 34e at the midpoint of the 1 / 4 position from the left), the amount of warping of the field unit was 0.38 times because it is supported by the spacer 34e at the midpoint slightly to the left.

[0060] From the above, it can be seen that, in all cases, the configuration of the lens drive device 10 of this embodiment was able to suppress the amount of deformation of the field unit compared to the comparative example configuration in which only two ends are supported or the comparative example configuration in which the yoke is divided into two parts. In particular, it was found that the amount of warping of the field unit 33a etc. can be suppressed to about 1 / 6 in the configuration of Embodiment 1 (Figure 14C) compared to the comparative example configuration in which the field unit 33a etc. is supported only at both ends (Figure 14A).

[0061] As a result, the amount of warping of the field unit can be effectively suppressed, which in turn allows for a thinner yoke and a smaller, lighter lens drive device 10. In the above embodiment, a configuration in which a spacer 34e is provided at only one intermediate position was described, but it goes without saying that a configuration in which spacers are placed at two or more intermediate positions will produce the same effect.

[0062] <Main Features> The lens drive device 10 of this embodiment comprises a movable frame such as a 5-group unit 20, a field unit 33a, an n-phase coil 25a, insertion support parts 31da, 37ba, and a spacer 34e. The movable frame such as the 5-group unit 20 is movable in the optical axis direction and holds the lens L5, etc. The field unit 33a has magnets with alternating N poles and S poles arranged along the optical axis direction. The n-phase coil 25a is positioned in the 5-group unit 20 close to the field unit 33a, has a winding axis in a direction substantially perpendicular to the optical axis of the lens L5, and is arranged in a row along the optical axis direction. The insertion support parts 31da, 37ba support both ends of the field unit 33a in the optical axis direction. The spacer 34e supports the field unit 33a at an intermediate position and suppresses warping of the field unit 33a.

[0063] As a result, even if the field unit 33a attempts to deform due to its own weight or the magnetic attraction force between field units 33a and 33b, which are positioned opposite each other in close proximity, the spacer 34e can suppress the deformation of the field unit 33a. This effectively prevents warping of the field unit 33a. Similarly, the other field units 33b, 33c, and 33d can also be deformed by the spacer 34e even if they attempt to deform due to their own weight or the magnetic attraction force between field units positioned opposite each other in close proximity.

[0064] (Embodiment 2) A lens drive device 110 and a lens barrel 130 equipped therewith, according to another embodiment of the present disclosure, will be described below with reference to Figures 15A to 18. In Embodiment 1, an example was given in which the magnets 33aa, 33ba, 33ca, and 33da included in the field units 33a, 33b, 33c, and 33d are connected without gaps from the first group unit 31 to the seventh group unit 37 in the optical axis direction.

[0065] The lens barrel 130 according to this second embodiment, as shown in Figures 15A and 15B, includes field units 133a, 133b, 133c, and 133d, which include magnets 133aa, 133ba, 133ca, and 133da that are divided into two in the longitudinal direction so as to provide a gap near the intermediate position, and a lens drive device 110 in which a spacer 134e is placed in the gap.

[0066] In this configuration, as shown in Figure 16, the magnets 133aa, 133ba, 133ca, and 133da are connected so that the north and south poles alternate, and magnets with half the width in the optical axis direction are bonded and fixed to both ends. The yokes 33ab, 33bb, 33cb, and 33db, which are positioned in contact with the magnets 133aa, 133ba, 133ca, and 133da, all have the same shape and structure.

[0067] The spacer 134e is positioned near the midpoint of the longitudinal direction of the yokes 33ab, 33bb, 33cb, and 33db, in the gap between the magnets 133aa, 133ba, 133ca, and 133da, and supports the yokes 33ab, 33bb, 33cb, and 33db in the radial direction. At this time, the magnets 133aa, 133ba, 133ca, and 133da, which are divided into two halves in the front and back in the optical axis direction, are positioned separately and then bonded together.

[0068] This prevents, for example, when magnets 133aa, 133ba, 133ca, and 133da are positioned at one first end, the tolerance in the width dimension in the optical axis direction can cause the tolerance to accumulate for each magnet 133aa, 133ba, 133ca, and 133da, resulting in large variations in the positions of the magnets 133aa, 133ba, 133ca, and 133da at the other second end.

[0069] Here, the relationship between the two-group unit 32 and the field units 133a, 133b, 133c, and 133d included in the lens driving device 110 shown in Figure 15B will be explained using Figures 17A and 17B. In the case where a spacer 34e is provided between the magnets as in Embodiment 1 above, the coil and the spacer 34e interfere with each other, which limits the range in which the coil can move, and there is a risk that the range in which the coil can move will become smaller with respect to the optical axis length of the magnet.

[0070] On the other hand, in the configuration shown in this second embodiment, in which the magnets 133aa, 133ba, 133ca, and 133da included in the field units 133a, 133b, 133c, and 133d are divided into two sections in the optical axis direction, the coil can be moved along the entire optical axis length of the magnet by arranging the spacer 134e in the area where no magnet is placed.

[0071] For example, as shown in Figures 17A and 17B, when the coil 32a of the two-group unit 32 moves back and forth in the optical axis direction, it moves between the magnets 133aa and 133ba, which are divided into two parts in the optical axis direction, and the magnets 133aa and 133ba that are positioned on the subject side. At the end opposite to the subject, the end of the magnets 133aa and 133ba that is opposite to the subject can move to a position where a part of it protrudes from the end of the magnets 133aa and 133ba on the opposite side of the subject.

[0072] Here, the spacer 134e, which is inserted between the magnets 133aa and 133ba that are divided into two sections in the optical axis direction, is formed in a concave shape at the height position where the coil 32a moves, as shown in Figure 16. By designing the shape of the spacer 134e to be concave, interference between the spacer 134e and the coil 32a can be avoided, and the entire area of ​​the magnets 133aa and 133ba can be used.

[0073] Similarly, with respect to the coil 32b of the two-group unit 32, when it moves back and forth in the optical axis direction, it moves between the magnets 133ca and 133da, which are positioned on the subject side of the two divided magnets 133aa and 133ba in the optical axis direction, and at the end opposite to the subject, the end of the magnets 133ca and 133da opposite to the subject can move to a position where a portion of it protrudes from the end of the magnets 133ca and 133da on the opposite side of the subject.

[0074] Here, the spacer 134e, which is inserted between the magnets 133ca and 133da that are divided into two parts in the optical axis direction, is formed in a concave shape at the height position where the coil 32b moves, as shown in Figure 16. By designing the shape of the spacer 134e to be concave, interference between the spacer 134e and the coil 32b can be avoided, and the entire area of ​​the magnets 133ca and 133da can be used.

[0075] Normally, at the ends of magnets 133aa, 133ba, 133ca, and 133da, as shown in Figure 18, if coils 32a and 32b move beyond their ends, the thrust may decrease rapidly, rendering them unusable. However, in this embodiment, even with a configuration where magnets 133aa, 133ba, 133ca, and 133da are divided into two in the optical axis direction, if coils 32a and 32b move to a position where they slightly protrude through the gap in the central part of the division, they can maintain thrust because they receive magnetic force from the magnets 133aa, 133ba, 133ca, and 133da on the opposite side of the object in the optical axis direction, which are positioned through the gap.

[0076] As a result, even with a configuration in which the magnets 133aa, 133ba, 133ca, and 133da are divided into two sections in the front and back in the optical axis direction, as in this embodiment, the movable frame (coil) can be driven over a wider range without limiting its range of motion. Furthermore, since magnets are expensive, reducing the amount of magnets used as much as possible can help reduce costs.

[0077] [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. (A) In the above embodiment, an example was given in which a single spacer 34e supporting the field unit 33a radially is provided at an intermediate position in the longitudinal direction of the field unit 33a. However, the present disclosure is not limited thereto.

[0078] For example, a configuration may be provided in which two or more spacers (warping suppression parts) are provided at two locations in the longitudinal direction of the field part to support the field part radially. (B) In the above embodiment, an example was given in which the spacer 34e is provided in the gap between two opposing field units 33a and 33b. However, the present disclosure is not limited thereto.

[0079] For example, the spacer may be configured to support one field section radially, rather than between two field sections. (C) In the above embodiment, field units 33a and 33c arranged radially outward from the optical axis were described as the first field section, and field units 33b and 33d arranged radially inward were described as the second field section. However, the present disclosure is not limited thereto.

[0080] For example, the configuration corresponding to the first field section may be field units 33b and 33d arranged radially inward from the optical axis, and the configuration corresponding to the second field section may be field units 33a and 33c arranged radially inward. (D) In ​​the above embodiment, an example in which the lens drive device 10 according to the present disclosure is mounted on the lens barrel 30 of a video camera 50 has been described. However, the present disclosure is not limited thereto.

[0081] For example, the lens drive device according to this disclosure may be mounted on a lens barrel that is attached to a camera body in a manner that is detachable or indetachable, rather than on a video camera. <Note> The following technologies are disclosed by the above description of embodiments. (Technology 1) The lens drive device according to Technology 1 comprises: a movable frame that is movable in the optical axis direction and holds a lens; a first field section having magnets with alternating N poles and S poles arranged along the optical axis direction; n-phase coils arranged in a position adjacent to the first field section on the movable frame, having a winding axis in a direction substantially perpendicular to the optical axis of the lens, and arranged in a row along the optical axis direction; end support sections that support both ends of the first field section in the optical axis direction; and a warp suppression section that supports the first field section at an intermediate position in the first field section and suppresses warping of the first field section.

[0082] (Technology 2) The lens driving device according to Technology 2 is the lens driving device according to Technology 1, further comprising a second field section positioned opposite the first field section so as to sandwich the coil. (Technology 3) The lens driving device according to Technology 3 is the lens driving device according to Technology 2, wherein the warping suppression section is positioned in the gap between the first field section and the second field section.

[0083] (Technology 4) The lens driving device according to Technology 4 is a lens driving device according to any one of Technologies 1 to 3, wherein the warping suppression part is a plate-shaped member arranged in a direction perpendicular to the optical axis of the lens.

[0084] (Technology 5) The lens driving device according to Technology 5 is a lens driving device according to any one of Technologies 1 to 4, further comprising a fixed frame arranged in a state that it cannot move in the optical axis direction, and the warping suppression part is provided on the fixed frame.

[0085] (Technology 6) The lens driving device according to Technology 6 is the lens driving device according to Technology 5, wherein the fixed frame has an opening into which the first field section is inserted, and the warping suppression section is positioned adjacent to the opening. (Technology 7) The lens driving device according to Technology 7 is the lens driving device according to any one of Technologies 1 to 6, wherein the end support section has a support opening into which the end of the first field section is inserted.

[0086] (Technology 8) The lens driving device according to Technology 8 is a lens driving device according to any one of Technologies 1 to 7, wherein the warp suppression part is arranged in the gap between the magnets at the intermediate position. (Technology 9) The lens driving device according to Technology 9 is a lens driving device according to Technology 8, wherein the magnets, in which the N poles and S poles are arranged alternately, are positioned and fixed separately before and after the intermediate position.

[0087] (Technology 10) The lens drive device according to Technology 10 is a lens drive device according to any one of Technologies 1 to 9, wherein the warping suppression parts are provided in multiples at predetermined intervals. (Technology 11) The lens barrel according to Technology 11 comprises a lens drive device according to any one of Technologies 1 to 10, and a cylindrical member enclosing the lens drive device.

[0088] The lens drive device of this disclosure has the effect of effectively preventing the occurrence of warping of the magnetic field section, and is therefore widely applicable to mechanisms that move lenses back and forth in the optical axis direction.

[0089] 10 Lens drive device 20 5-group unit (moving frame) 21 OIS yoke 22a, 22b Magnet 23a, 23b Drive magnet 24 5-group frame 25a Coil 25b Coil 26a OIS ball 26b OIS biasing spring 26ca, 26cb Hall element 27a, 27b Coil 28 OIS frame 29 Cover 30 Lens barrel 31 1-group unit (cylindrical member) 31a, 31b Guide shaft 31c Main body 31da, 31db Insertion support part (both end support parts, support opening) 32 2-group unit (moving frame) 32a, 32b Coil 33a Field unit (first field part) 33aa Magnet 33ab Yoke 33ac, 33ad End 33b Field unit (second field section) 33ba Magnet 33bb Yoke 33bc, 33bd End 33c Field unit (first field section) 33ca Magnet 33cb Yoke 33cc, 33cd End 33d Field unit (second field section) 33da Magnet 33db Yoke 33dc, 33dd End 34 3-group unit (fixed frame) 34a Main body 34aa Lens holder 34ba, 34bb Guide shaft 34c Aperture unit 34d Insertion hole (opening) 34e Spacer (warp suppression section) 35 4-group unit (movable frame) 35a Main body 35b Lens holder 35c Guide hole 35d Coil mounting section 35e Coil 36 6-group unit (movable frame) 36a Main body 36b Lens holder 36c Guide hole 36d Coil mounting part 36e Coil 37 7-group unit 37a Main body 37ba, 37bb Insertion support part (both end support parts, support opening) 37c Screw 38 IR unit 39 Image sensor unit 39a Image sensor 50 Video camera 51 Camera body 52 Lens hood 110 Lens drive device 130 Lens barrel 133a, 133b Field unit 133aa, 133ba Magnet 133c, 133d Field unit 133ca, 133da Magnet 134e Spacer (warp suppression part) L1, L2, L3, L4, L5,L6, L7 lenses,

Claims

1. A lens driving device comprising: a movable frame that is movable in the optical axis direction and holds a lens; a first field section having magnets with alternating N poles and S poles arranged along the optical axis direction; n-phase coils arranged in parallel along the optical axis direction, having a winding axis in a direction substantially perpendicular to the optical axis of the lens, and positioned adjacent to the first field section on the movable frame; end support sections that support both ends of the first field section in the optical axis direction; and a warp suppression section that supports the first field section at an intermediate position and suppresses warping of the first field section.

2. The lens drive device according to claim 1, further comprising a second field section positioned opposite the first field section so as to sandwich the coil.

3. The lens driving device according to claim 2, wherein the warping suppression part is disposed in the gap between the first field part and the second field part.

4. The lens driving device according to claim 1 or 2, wherein the warping suppression portion is a plate-shaped member arranged along a direction perpendicular to the optical axis of the lens.

5. The lens driving device according to claim 1 or 2, further comprising a fixed frame positioned so as to be immovable in the optical axis direction, wherein the warping suppression unit is provided on the fixed frame.

6. The lens driving device according to claim 5, wherein the fixed frame has an opening into which the first field section is inserted, and the warping suppression section is positioned adjacent to the opening.

7. The lens drive device according to claim 1 or 2, wherein the end support portion has a support opening into which the end portion of the first magnetic field portion is inserted.

8. The lens driving device according to claim 1 or 2, wherein the warping suppression portion is arranged in the gap between the magnets at the intermediate position.

9. The lens driving device according to claim 8, wherein the magnets, in which the north poles and south poles are arranged alternately, are positioned and fixed separately before and after the intermediate position.

10. The lens driving device according to claim 1 or 2, wherein a plurality of the warping suppression parts are provided at predetermined intervals.

11. A lens barrel comprising: a lens driving device according to claim 1 or 2; and a cylindrical member enclosing the lens driving device.

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