Lens drive device, lens unit, and camera

Abstract

To increase the impact resistance of a lens driving device, while increasing the thrust of a voice coil motor.SOLUTION: A coil (44) is inserted into a yoke (36) movably relative to an optical axis direction. Holding parts (48) that hold magnets (42) against an inside surface of the yoke (36) by a wedge action are provided respectively at both ends in the optical axis direction in the yoke (36). The holding parts (48) are in pressure contact with end faces in the optical axis direction of the magnets (42).SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a lens driving device, a lens unit, and a camera that move a lens in a predetermined direction that is the optical axis direction or a direction orthogonal thereto.

Background Art

[0002] As a prior art of a lens driving device, there is one disclosed in Patent Document 1. The lens driving device according to this prior art includes a lens holder (referred to as a lens frame in Patent Document 1) that holds a lens, and the lens holder is provided in a lens barrel so as to be movable in the optical axis direction as a predetermined direction. The lens driving device includes a voice coil motor for moving the lens holder in the optical axis direction.

[0003] The voice coil motor has a box-shaped yoke provided on the inner peripheral wall side of the lens barrel, a magnet provided on the inner surface of the yoke, and a coil (referred to as an electromagnetic coil in Patent Document 1) provided on the outer peripheral wall side of the lens holder. The coil faces the magnet and is inserted into the yoke so as to be movable in the optical axis direction. Further, the voice coil motor has a pair of pressing portions (referred to as suppressing members in Patent Document 1) for pressing the magnet so that the magnet does not come off from the inner surface of the yoke. The pair of pressing portions are provided on both end sides in the optical axis direction within the yoke, respectively. Each pressing portion is made of a sheet metal material and has a pressed piece (referred to as a suppressing piece in Patent Document 1) formed by bending.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, in lens drive devices of prior art, it is necessary to widen the gap between the magnet and the coil by the thickness of the retaining piece of the retaining part, which reduces the effective magnetic flux that contributes to the generation of thrust in the voice coil motor, thus hindering the increase in thrust of the voice coil motor. On the other hand, if a large magnet or two magnets with opposing magnetic poles are used to increase the effective magnetic flux, the magnet is more likely to detach (separate) from the inner surface of the yoke due to the impact acting on the lens drive device, reducing the impact resistance of the lens drive device.

[0006] Therefore, one aspect of the present invention aims to increase the thrust of the voice coil motor while improving the shock resistance of the lens drive device. [Means for solving the problem]

[0007] To solve the aforementioned problems, a lens driving device according to embodiment 1 of the present invention comprises a lens holder that is provided within a lens barrel so as to be movable in a predetermined direction (movement direction) which is the optical axis direction of the lens or a direction perpendicular thereto, and which holds the lens, and a voice coil motor for moving the lens holder in the predetermined direction. The voice coil motor comprises a box-shaped yoke provided on one of the inner circumferential wall side of the lens barrel and the outer circumferential wall side of the lens holder, a magnet provided on the inner surface of the yoke, a coil provided on the other of the inner circumferential wall side of the lens barrel and the outer circumferential wall side of the lens holder, inserted into the yoke so as to be relatively movable in the predetermined direction and facing the magnet, and pressing parts (pressing members) provided on both ends of the predetermined direction within the yoke, which press against the end face of the magnet in the predetermined direction and press the magnet to the inner surface side of the yoke by wedge action.

[0008] Furthermore, a lens unit according to one aspect of the present invention comprises a lens barrel, a lens disposed within the lens barrel, and a lens driving device according to one aspect of the present invention for moving the lens in the predetermined direction.

[0009] Furthermore, a camera according to one aspect of the present invention comprises a camera body and a lens unit according to one aspect of the present invention provided on the camera body. [Effects of the Invention]

[0010] According to one aspect of the present invention, it is possible to increase the thrust of the voice coil motor while improving the shock resistance of the lens drive device. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic side view of a camera according to an embodiment of the present invention. [Figure 2] This is a schematic perspective view of a lens drive device according to an embodiment of the present invention. [Figure 3] Figure 2 is a schematic cross-sectional view of the lens drive device. [Figure 4] This is a schematic cross-sectional view of a voice coil motor according to an embodiment of the present invention, along the optical axis direction. [Figure 5] Figure 4 is a schematic cross-sectional view showing the yoke segments of a voice coil motor before they are assembled. [Figure 6] Figure 4 is a front view of the voice coil motor. [Figure 7] This is a schematic partial cross-sectional view along the line VII-VII in Figure 6. [Figure 8] This is a schematic partial cross-sectional view along the line VIII-VIII in Figure 6. [Figure 9] This is a schematic cross-sectional view along the optical axis direction of a voice coil motor according to a modified example 1 of this embodiment. [Figure 10] This is a schematic cross-sectional view along the optical axis direction of a voice coil motor according to a modified example 2 of this embodiment. [Figure 11] This is a schematic cross-sectional view along the optical axis direction of a voice coil motor according to a modified example 3 of this embodiment. [Modes for carrying out the invention]

[0012] Hereinafter, this embodiment will be described with reference to the drawings. The "optical axis" refers to the optical axis of a lens such as a focus lens or the optical axis of a lens unit. The "optical axis direction" refers to the axial direction of the optical axis, and in this embodiment, it is the front-back direction. The "radial direction" refers to the radial direction of the lens or the radial direction of the lens barrel. In the drawings, "OA" indicates the optical axis, "AD" indicates the optical axis direction, "FF" indicates the front direction, and "FR" indicates the rear direction, respectively.

[0013] 〔This Embodiment〕 Referring to FIG. 1, the outline of the camera according to this embodiment will be described. FIG. 1 is a schematic side view of the camera according to the embodiment of the present invention.

[0014] (Outline of Camera 10) As shown in FIG. 1, the camera 10 according to this embodiment includes a camera body 12 and a lens unit 14 provided on the camera body 12. The lens unit 14 forms an image of the incident light on the film surface (image pickup element surface) F in the camera body 12.

[0015] The lens unit 14 includes a lens barrel 16 provided on the camera body 12. A plurality of fixed lenses 18 are arranged in the lens barrel 16. In the lens barrel 16, a focus lens 20 for focus adjustment is arranged so as to be movable in the optical axis direction (front-back direction). Further, the lens unit 14 includes a lens driving device 22 that moves the focus lens 20 in the optical axis direction as a predetermined direction.

[0016] A focus ring 24 for manually operating the movement amount of the focus lens 20 is rotatably provided on the outer peripheral wall of the lens barrel 16. When the photographer rotates the focus ring 24, the lens driving device 22 moves the focus lens 20 in the optical axis direction based on the operation amount.

[0017] On the outer wall of the camera body 12, there is a release button 26 for focusing by automatic focusing. When the photographer presses the release button 26 halfway, the lens driving device 22 moves the focus lens 20 in the optical axis direction based on a control signal from an automatic focus control unit 28 built into the camera body 12 so that the image of the subject is in focus on the film F.

[0018] Subsequently, referring to FIGS. 2 to 8, the configuration of the lens driving device 22 according to the present embodiment will be described. FIG. 2 is a schematic perspective view of the lens driving device according to the embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of the lens driving device shown in FIG. 2. FIG. 4 is a schematic cross-sectional view along the optical axis direction of the voice coil motor according to the embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing the state before assembling the yoke segments in the voice coil motor shown in FIG. 4. FIG. 6 is a front view of the voice coil motor shown in FIG. 4. In FIG. 6, the illustration of the coil is omitted. FIG. 7 is a schematic partial cross-sectional view along line VII-VII in FIG. 6. FIG. 8 is a schematic partial cross-sectional view along line VIII-VIII in FIG. 6.

[0019] (Overview of the lens driving device 22, lens holder 30, voice coil motor 34) As shown in FIGS. 2 and 3, the lens driving device 22 according to the present embodiment is a device that moves the focus lens 20 in the optical axis direction (front-back direction) as described above. The lens driving device 22 includes a lens holder 30 that holds the focus lens 20. The lens holder 30 is provided movably in the optical axis direction within the lens barrel 16 via a pair of guide rods 32. The lens driving device 22 includes a pair of voice coil motors 34 for moving the lens holder 30 in the optical axis direction.

[0020] (Yoke 36, yoke segments 38, 40) As shown in Figures 2 to 4, each voice coil motor 34 has a box-shaped yoke 36 provided on the inner circumferential wall 16i side of the lens barrel 16. Both sides of each yoke 36 in the direction perpendicular to the radial direction are open. Each yoke 36 is made of a magnetic material. Each yoke 36 has two yoke segments 38, 40 divided along its circumferential direction, and the cross-sectional shapes of the two yoke segments 38, 40 are formed in an L-shape.

[0021] As shown in Figures 4 to 6, one end of the first yoke segment 38 has an engaging projection 38s that protrudes to one side in a direction perpendicular to the optical axis. The other end of the first yoke segment 38 has an engaging recess 38d that is recessed to one side in the optical axis. One end of the second yoke segment 40 has an engaging recess 40d that is recessed to the other side in the optical axis. The other end of the second yoke segment 40 has an engaging projection 40s that protrudes to the other side in a direction perpendicular to the optical axis. The engaging projection 38s of the first yoke segment 38 engages with the engaging recess 40d of the second yoke segment 40. The engaging projection 40s of the second yoke segment 40 engages with the engaging recess 38d of the first yoke segment 38.

[0022] (Magnet 42) As shown in Figures 3 and 4, each voice coil motor 34 has magnets 42 provided on both inner surfaces 36i of the yoke 36 in a direction perpendicular to the optical axis. Within the yoke 36 of each voice coil motor 34, a pair of magnets 42 are arranged so that their different magnetic poles face each other. Each magnet 42 is a rectangular plate-shaped permanent magnet and may be bonded to the inner surface 36i of the yoke 36. On both end faces of each magnet 42 in the direction of the optical axis, inclined surfaces 42f are formed, which are inclined with respect to the thickness direction of each magnet 42.

[0023] (Coil 44) As shown in Figures 2 to 4, each voice coil motor 34 has a flat coil 44 provided on the outer peripheral wall 30e side of the lens holder 30. Each coil 44 is formed in an annular (frame-shaped) manner, and the contour shape of each coil 44 is formed in a substantially rectangular shape. The winding of each coil 44 is wound around an axis perpendicular to the optical axis direction. Each coil 44 faces two magnets 42 and is relatively inserted into the yoke 36 so as to be movable in the optical axis direction. Both ends of each coil 44 protrude from the yoke 36. Each end of each coil 44 is bent along the outer peripheral wall 30e of the lens holder 30 so as to approach the optical axis of the focus lens 20 (the center of the focus lens 20). Note that instead of forming the contour shape of each coil 44 in a substantially rectangular shape, it may be formed in a circular, fan-shaped, rhombus-shaped, or trapezoidal shape, for example.

[0024] (Holding member 46) As shown in Figures 2 and 3, three mounting portions 30m are formed on the outer peripheral wall 30e of the lens holder 30 at intervals in the circumferential direction. Each mounting portion 30m of the lens holder 30 is provided with a clamping member 46 that clamps the end side of the coil 44 of each voice coil motor 34. One of the three mounting portions 30m of the lens holder 30 is provided with two clamping members 46. One of the two clamping members 46 clamps the end side of the coil 44 of one voice coil motor 34. The other clamping member 46 clamps the end side of the coil 44 of the other voice coil motor 34. Each clamping member 46 is made of synthetic resin. As described above, each coil 44 is provided on the outer peripheral wall 30e side of the lens holder 30 via the two clamping members 46 by each clamping member 46 clamping the end side of each coil 44.

[0025] (Magnetic circuits, etc.) In each voice coil motor 34, the yoke 36 is configured to guide the magnetism of the magnet 42 towards the coil 44, forming a closed annular magnetic circuit. The yoke 36 and the two magnets 42 form a magnetic circuit. When current flows through the winding of the coil 44 in each voice coil motor 34, the magnetic circuit generates a driving force in the optical axis direction, causing the coil 44 to move in the optical axis direction relative to the yoke 36. As a result, the lens holder 30 and the focus lens 20 move integrally with the coil 44 in the optical axis direction.

[0026] (Pressing part 48) As shown in Figures 4, 7, and 8, each voice coil motor 34 is provided with a pressing portion (pressing member) 48 at both ends in the optical axis direction within the yoke 36, which presses the two magnets 42 against the inner surface 36i of the yoke 36 by wedge action. Each pressing portion 48 is made of a separate component from the yoke 36 and may be made of either a non-magnetic or magnetic material. One of the two pressing portions 48 is provided on the first yoke segment 38, and the other pressing portion 48 is provided on the second yoke segment 40.

[0027] As shown in Figures 7 and 8, each pressing portion 48 has two pressing surfaces 48f that are parallel to the inclined surfaces 42f of the two magnets 42. One of the two pressing surfaces 48f of each pressing portion 48 presses against the inclined surface 42f of one of the two magnets 42. The other pressing surface 48f of each pressing portion 48 presses against the inclined surface 42f of the other of the two magnets 42. In other words, each pressing surface 48f of each pressing portion 48 presses against the inclined surface 42f, which is the end face of each magnet 42.

[0028] As shown in Figures 6 and 8, a boss portion 48b is formed in the center of each pressing portion 48. The boss portion 48b of each pressing portion 48 is supported in a support hole 36h formed in the yoke 36 so as to be movable in the thickness direction of the magnet 42. In other words, the boss portion 48b of each pressing portion 48 and the support hole 36h of the yoke 36 allow each pressing portion 48 to move in the thickness direction of the magnet 42.

[0029] (Effects and Benefits) Next, the effects and advantages of the embodiments of the present invention will be described.

[0030] As described above, in the lens drive device 22, pressing portions 48 are provided at both ends in the optical axis direction within the yoke 36, pressing the two magnets 42 against the inner surface 36i of the yoke 36 by wedge action. Each pressing surface 48f of each pressing portion 48 is pressed against the inclined surface 42f, which is the end face of each magnet 42. Therefore, while maintaining a small gap between the magnet 42 and the coil 44, the wedge action of the pressing portion 48 can be effectively exerted, and the fixing force (adhesion force) of the magnet 42 to the inner surface 36i of the yoke 36 can be sufficiently increased. As a result, even when two magnets 42 with opposing magnetic poles are used, it is possible to prevent the magnets 42 from detaching (peeling off) from the inner surface 36i of the yoke 36 due to the impact acting on the lens drive device 22. Therefore, according to this embodiment, the effective magnetic flux contributing to the thrust of the voice coil motor 34 can be increased, thereby increasing the thrust of the voice coil motor 34, while also improving the shock resistance of the lens drive device 22, in other words, the shock resistance of the lens unit 14 and the camera 10.

[0031] Furthermore, in the lens drive device 22, as described above, each retaining portion 48 has two pressing surfaces 48f that are parallel to the inclined surfaces 42f of the two magnets 42. Therefore, according to this embodiment, the space required to arrange the retaining portions 48 within the yoke 36 can be reduced, thereby enabling miniaturization of the lens drive device 22, or in other words, miniaturization of the lens unit 14 and the camera 10.

[0032] Furthermore, in the lens drive device 22, as described above, the yoke 36 has two yoke segments 38 and 40 divided along its circumferential direction. One of the two pressing parts 48 is provided on the first yoke segment 38, and the other pressing part 48 is provided on the second yoke segment 40. Therefore, when assembling the yoke 36 from the multiple yoke segments 38 and 40, each pressing surface 48f of each pressing part 48 can be pressed (closely attached) to each inclined surface 42f of the magnet 42. As a result, according to this embodiment, the manufacturing of the lens drive device 22 is simplified, and the manufacturing cost of the lens drive device 22 can be reduced, in other words, the manufacturing cost of the lens unit 14 and the manufacturing cost of the camera 10 can be reduced.

[0033] Furthermore, in the lens drive device 22, as described above, each pressing portion 48 is allowed to move in the thickness direction of the magnet 42. Therefore, even if there is variation in the dimensions of the magnet 42, this variation can be absorbed by any of the pressing portions 48 moving relative to the yoke 36 in the thickness direction of the magnet 42. As a result, according to this embodiment, each pressing surface 48f of each pressing portion 48 can be brought into close contact with the inclined surface 42f of each magnet 42, thereby sufficiently increasing the fixing force of the magnet 42 against the inner surface 36i of the yoke 36.

[0034] [Modification 1 of this embodiment] Referring to Figure 9, a voice coil motor according to Modification 1 of this embodiment will be described. Figure 9 is a schematic cross-sectional view of the voice coil motor according to Modification 1 of this embodiment along the optical axis direction. For the sake of explanation, components having the same function as those described in this embodiment will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0035] (York segments 50, 52) As shown in Figure 9, in the voice coil motor 34A according to Modification 1 of this embodiment, the yoke 36 has two yoke segments 50 and 52 divided along its circumferential direction. The cross-sectional shape of the first yoke segment 50 is formed in a transverse U shape, and the second yoke segment 52 is formed in a plate shape. Engaging protrusions 50s are formed at both ends of the first yoke segment 50, projecting to one side in the optical axis direction. Engaging recesses 52d are formed at both ends of the second yoke segment 52, recessed to one side or the other side in a direction perpendicular to the optical axis direction. Each engaging protrusion 50s of the first yoke segment 50 engages with each engaging recess 52d of the second yoke segment 52. One of the two retaining portions 48 is provided on the first yoke segment 50, and the other retaining portion 48 is provided on the second yoke segment 52.

[0036] (Chip 54) The voice coil motor 34A has a cylindrical coil 54 provided on the outer peripheral wall 30e side (see Figure 3) of the lens holder 30. The winding of the coil 54 is wound around an axis parallel to the optical axis direction. The coil 54 faces the two magnets 42 and is relatively inserted within the yoke 36 so as to be movable in the optical axis direction.

[0037] (Effects and Benefits) Furthermore, the modified example 1 of this embodiment also produces the same effects and advantages as the embodiment described above.

[0038] [Modification of the embodiment 2] Referring to Figure 10, a voice coil motor according to Modification 2 of this embodiment will be described. Figure 10 is a schematic cross-sectional view of the voice coil motor according to Modification 2 of this embodiment along the optical axis direction. For the sake of explanation, components having the same function as those described in this embodiment will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0039] (Pressing part 48) In the voice coil motor 34B according to the modified example 2 of this embodiment, a retaining portion (retaining member) 48 is provided at one end of the yoke 36 in the optical axis direction. The retaining portion 48 is made of a separate part from the yoke 36. At the other end of the yoke 36 in the optical axis direction, a retaining portion 36p is provided that presses the two magnets 42 against the inner surface 36i of the yoke 36 by wedge action. The retaining portion 36p is made of a part of the yoke 36. The retaining portion 36p has two pressing surfaces 36f formed on it, each parallel to the inclined surface 42f of the two magnets 42. One of the two pressing surfaces 36f of the retaining portion 36p presses against the inclined surface 42f of one of the two magnets 42. One of the two pressing surfaces 36f of the pressing portion 36p presses against the inclined surface 42f of the other of the two magnets 42. In other words, each pressing surface 36f of the pressing portion 36p presses against the inclined surface 42f, which is the end face of each magnet 42.

[0040] (Effects and Benefits) Furthermore, the modified example 2 of this embodiment also produces the same effects and advantages as the embodiment described above.

[0041] [Modification of Embodiment 3] Referring to Figure 11, a voice coil motor according to Modification 3 of this embodiment will be described. Figure 11 is a schematic cross-sectional view of the voice coil motor according to Modification 3 of this embodiment along the optical axis. For the sake of explanation, components having the same function as those described in this embodiment will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0042] (Magnet 42) As shown in Figure 11, in the voice coil motor 34C according to the third modification of this embodiment, a large magnet 42 is provided only on one inner surface 36i of the yoke 36 in a direction perpendicular to the optical axis direction.

[0043] (Effects and Benefits) Furthermore, in the third modification of this embodiment, while maintaining a small gap between the magnet 42 and the coil 44, the wedge action of the retaining portion 48 is effectively exerted, thereby sufficiently increasing the fixing force (adhesion force) of the magnet 42 to the inner surface 36i of the yoke 36. As a result, even when a large magnet 42 is used, it is possible to prevent the magnet 42 from detaching (peeling off) from the inner surface 36i of the yoke 36 due to the impact acting on the lens drive device 22 (see Figure 2). Therefore, according to the third modification of this embodiment, the effective magnetic flux contributing to the thrust of the voice coil motor 34 can be increased, thereby increasing the thrust of the voice coil motor 34 while improving the impact resistance of the lens drive device 22.

[0044] Furthermore, the third modification of this embodiment also produces the same effects and advantages as the embodiment described above.

[0045] [Other aspects of this embodiment] Instead of providing the yoke 36 on the inner circumferential wall 16i side of the lens barrel 16, it may be provided on the outer circumferential wall 30e side of the lens holder 30. In this case, the coil 44 is provided on the inner circumferential wall 16i side of the lens barrel 16. Furthermore, the configuration of the lens drive device 22 described above may be applied to other lens drive devices (not shown) that move a zoom lens (not shown) for zoom adjustment in the optical axis direction as a predetermined direction.

[0046] The configuration of the lens drive device 22 described above may also be applied to other lens drive devices (not shown) that move a correction lens (not shown) for image shake correction in a predetermined direction perpendicular to the optical axis. In this case, a box-shaped yoke (not shown) or coil (not shown) is provided on the inner circumferential wall side of the lens barrel 16 via a fixing member (not shown).

[0047] 〔summary〕 A lens drive device according to embodiment 1 of the present invention comprises a lens holder that is provided within a lens barrel so as to be movable in a predetermined direction (movement direction) which is the optical axis direction of the lens or a direction perpendicular thereto, and which holds the lens, and a voice coil motor for moving the lens holder in the predetermined direction, wherein the voice coil motor comprises a box-shaped yoke provided on one of the inner circumferential wall side of the lens barrel and the outer circumferential wall side of the lens holder, a magnet provided on the inner surface of the yoke, a coil provided on the other of the inner circumferential wall side of the lens barrel and the outer circumferential wall side of the lens holder, inserted into the yoke so as to be relatively movable in the predetermined direction and facing the magnet, and pressing parts (pressing members) provided on both ends of the predetermined direction within the yoke, which press against the end face of the magnet in the predetermined direction and press the magnet to the inner surface side of the yoke by wedge action.

[0048] According to the above configuration, as described above, pressing portions are provided at both ends in the predetermined direction within the yoke, which press the magnet against the inner surface of the yoke by wedge action. Each pressing portion presses against the end face of the magnet in the predetermined direction. Therefore, it is possible to increase the fixing force (adhesion force) of the magnet against the inner surface of the yoke while maintaining a small gap between the magnet and the coil. As a result, even when using a large magnet or two magnets with opposing magnetic poles, it is possible to prevent the magnet from detaching (peeling off) from the inner surface of the yoke due to the impact acting on the lens drive device. Thus, it is possible to increase the effective magnetic flux contributing to the thrust of the voice coil motor, thereby increasing the thrust of the voice coil motor while improving the shock resistance of the lens drive device.

[0049] In the lens driving device according to embodiment 2 of the present invention, in embodiment 1, inclined surfaces are formed on both end faces of the magnet in the predetermined direction, inclined with respect to the thickness direction of the magnet, and pressing surfaces are formed on each pressing portion parallel to each inclined surface of the magnet, and the pressing surfaces of each pressing portion are pressed against the inclined surfaces of the magnet.

[0050] According to the above configuration, the pressing surface of each pressing part presses against the inclined surface of the magnet, thereby effectively exerting a wedge action by the pressing part and sufficiently increasing the fixing force (adhesion force) of the magnet to the inner surface of the yoke. Furthermore, the space required for arranging the pressing parts within the yoke can be reduced, allowing for miniaturization of the lens drive device.

[0051] In the lens driving device according to embodiment 3 of the present invention, in embodiment 2, the yoke has a plurality of yoke segments divided along its circumferential direction, one of the retaining portions is provided on one of the plurality of yoke segments, and the other retaining portion may be provided on another yoke segment.

[0052] According to the above configuration, when assembling the yoke from the plurality of yoke segments, the pressing surface of each retaining part can be pressed against (closely attached to) the inclined surface of the magnet. This simplifies the manufacturing of the lens drive device and reduces the manufacturing cost of the lens drive device.

[0053] In the lens driving device according to embodiment 4 of the present invention, in embodiment 3, at least one of the pair of retaining portions is made of a separate component from the yoke, and movement of the magnet in the thickness direction relative to the yoke is permitted.

[0054] According to the above configuration, even if there are variations in the dimensions of the magnets, these variations can be absorbed by any of the pressing portions moving in the thickness direction of the magnets relative to the yoke. This allows the pressing surfaces of each pressing portion to be brought into close contact with the inclined surface of the magnets, thereby sufficiently increasing the fixing force of the magnets against the inner surface of the yoke.

[0055] A lens unit according to embodiment 5 of the present invention comprises a lens barrel, a lens disposed within the lens barrel, and a lens driving device according to any of embodiments 1 to 4 for moving the lens in the predetermined direction.

[0056] According to the above configuration, it is possible to increase the thrust of the voice coil motor while improving the impact resistance of the lens unit equipped with the lens drive device.

[0057] A camera according to aspect 6 of the present invention comprises a camera body and a lens unit according to aspect 5 provided on the camera body.

[0058] With the above configuration, it is possible to increase the thrust of the voice coil motor while improving the impact resistance of the camera equipped with the lens unit.

[0059] [Additional Notes] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in each embodiment are also included within the technical scope of the present invention. [Explanation of Symbols]

[0060] 10 Cameras 12 Camera Body 14 Lens Unit 16 Lens barrel 16i Inner wall 18 Fixed Lens 20 Focus Lenses (Lenses) 22 Lens drive device 24 Focus Ring 26 Release button 28 Autofocus control unit 30 Lens Holder 30m mounting section 30e outer wall 32 Guide Rods 34 Voice coil motor 36 York 36i inner side 36h support hole 38. First yoke segment 38s Engagement protrusion 38d Engagement recess 40 Second York Segment 40s Engagement protrusion 40d Engagement recess 42 Magnets 42f slope 44 coils 46 Clamping member 48 Pressing part 48f Pressing surface 48b Boss section 34A Voice Coil Motor 50 First York Segment 50s Engagement protrusion 52 Second York Segment 52d Engagement recess 54 coils 34B Voice Coil Motor 36p Pressing part 36f Pressing surface 34C Voice Coil Motor

Claims

1. A lens holder is provided within the lens barrel so as to be movable in a predetermined direction that is either in the optical axis direction of the lens or perpendicular thereto, and holds the lens; The lens holder is provided with a voice coil motor for moving it in the predetermined direction, The aforementioned voice coil motor is A box-shaped yoke is provided on either the inner circumferential wall side of the lens barrel or the outer circumferential wall side of the lens holder, A magnet provided on the inner surface of the yoke, A coil is provided on the other of the inner circumferential wall side of the lens barrel and the outer circumferential wall side of the lens holder, inserted into the yoke so as to be relatively movable in the predetermined direction, and facing the magnet, A lens driving device having a pressing portion provided at both ends in the predetermined direction within the yoke, which presses against the end face of the magnet in the predetermined direction and presses the magnet toward the inner surface of the yoke by a wedge action.

2. The lens driving device according to claim 1, wherein inclined surfaces are formed on both end faces of the magnet in the predetermined direction, inclined with respect to the thickness direction of the magnet, and pressing surfaces are formed on each pressing portion parallel to the inclined surfaces of the magnet, and the pressing surfaces of each pressing portion press against the inclined surfaces of the magnet.

3. The lens driving device according to claim 2, wherein the yoke has a plurality of yoke segments divided along its circumferential direction, one of the retaining portions is provided on one of the plurality of yoke segments, and the other retaining portion is provided on another yoke segment.

4. The lens driving device according to claim 3, wherein at least one of the pair of pressing portions is made of a separate component from the yoke, and the magnet is permitted to move in the thickness direction relative to the yoke.

5. Lens barrel and The lens arranged inside the lens barrel, A lens unit comprising a lens driving device according to any one of claims 1 to 4 for moving the lens in the predetermined direction.

6. Camera body and A camera comprising a lens unit according to claim 5 provided on the camera body.

Images