JP2010286507A - Lens driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens driving device miniaturized while securing drive force for driving a lens. <P>SOLUTION: The lens driving device includes a movable body movable in an optical axis direction of the lens by holding the lens, and a drive mechanism 4 for driving the movable body in the optical axis direction. The drive mechanism 4 includes a plurality of substantially columnar drive magnet parts 17 arranged in the outer peripheral side of the movable body, a drive coil 18 wound in the form of a cylinder and arranged with the inner peripheral face thereof facing the outer peripheral face of the drive magnet parts 17 with a prescribed gap, and a magnetic plate 22 formed of a magnetic material and arranged on one end side of the drive magnet parts 17 in the optical axis direction. The drive magnet part 17 is magnetized so that a magnetic flux passing the drive coil 18 at a facing position of the drive coil 18 is generated. The magnetic plate 22 includes a plurality of covering parts 22a covering one end faces of the plurality of the drive magnet parts 17 respectively. The plurality of the covering parts 22a are integrated. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lens driving device used in a relatively small camera mounted on a mobile phone or the like.

  Conventionally, as a lens driving device for driving a photographing lens of a camera mounted on a mobile phone or the like, a moving lens body that moves in the optical axis direction while holding a plurality of lenses, and a moving lens via two leaf springs 2. Description of the Related Art A lens driving device including a fixed body that holds a body in a movable manner is known (see, for example, Patent Document 1). In the lens driving device described in Patent Document 1, a driving coil is wound around the outer periphery of a cylindrical sleeve constituting a moving lens body. In this lens driving device, four magnets are arranged so as to face the outer peripheral surface of the driving coil.

JP 2008-58659 A

  In recent years, in the market of cameras mounted on mobile phones and the like, there has been an increasing demand for miniaturization of cameras, and therefore, there has been a further increase in the demand for miniaturization of lens driving devices used in cameras. However, if a driving mechanism such as a driving coil or a magnet is downsized to reduce the size of the lens driving device, it may be difficult to obtain a driving force necessary to drive the lens.

  Accordingly, an object of the present invention is to provide a lens driving device that can be reduced in size while securing a driving force for driving the lens.

  In order to solve the above problems, a lens driving device of the present invention includes a movable body that holds a lens and is movable in the optical axis direction of the lens, and a drive mechanism that drives the movable body in the optical axis direction. The drive mechanism has a plurality of substantially columnar drive magnet portions disposed on the outer peripheral side of the movable body, and is wound in a substantially cylindrical shape, and the inner peripheral surface thereof is spaced from the outer peripheral surface of the drive magnet portion by a predetermined gap. And a magnetic plate formed of a magnetic material and disposed on one end side of the driving magnet unit in the optical axis direction, the driving magnet unit being positioned opposite to the driving coil. The magnetic plate is provided with a plurality of cover portions that respectively cover one end surfaces of the plurality of drive magnet portions, and the plurality of cover portions are integrated. It is characterized by.

  In the lens driving device of the present invention, the inner peripheral surface of the driving coil wound in a substantially cylindrical shape is disposed opposite to the outer peripheral surface of the driving magnet portion with a predetermined gap, and the driving magnet portion is It is magnetized so that a magnetic flux passing through the driving coil is generated at a position facing the driving coil. Therefore, it is possible to efficiently form a magnetic circuit for driving the movable body using the entire circumference of the drive magnet portion and the entire circumference of the drive coil. Therefore, it is possible to obtain a predetermined driving force for driving the movable body even if the driving magnet portion and the driving coil are reduced in size. As a result, according to the present invention, it is possible to reduce the size of the lens driving device while securing a driving force for driving the lens.

  In the present invention, the magnetic plate disposed on one end side of the drive magnet portion in the optical axis direction includes a plurality of cover portions that cover the respective one end surfaces of the plurality of drive magnet portions. Therefore, leakage of magnetic flux generated by the driving magnet unit can be suppressed, and an efficient magnetic circuit can be formed. In the present invention, the plurality of cover portions are integrated. Therefore, the number of parts can be reduced and the magnetic plate can be reduced in size as compared with the case where the cover that covers one end surface of the drive magnet unit is formed separately for each of the plurality of drive magnet units. However, handling of the magnetic plate at the time of manufacturing the lens driving device becomes easy. Further, as compared with the case where the cover is formed separately for each of the plurality of driving magnets, it is possible to suppress dust scattering generated by the driving mechanism by the magnetic plate. Moreover, when the cover part which covers the end surface of the drive magnet part is formed separately for each of the plurality of drive magnet parts, it is difficult to ensure the flatness and parallelism of the plurality of cover parts. However, in the present invention, since the plurality of cover parts are formed of an integrated part, the flatness and parallelism of the plurality of cover parts can be easily ensured in a uniform state.

  In the present invention, the lens driving device includes a case body formed of a magnetic material and disposed so as to surround the movable body and the driving mechanism, and the case body is driven so as to cover the other end surfaces of the plurality of driving magnet portions. The bottom portion is in contact with the other end surface of the magnet portion for use, and the bottom portion is formed in a substantially bottomed tubular shape including a movable body and a cylindrical portion disposed so as to surround the outer peripheral side of the drive mechanism. It is preferable to contact | abut to the one end surface. If comprised in this way, it will become possible to suppress the leakage of the magnetic flux which a drive magnet part generate | occur | produces effectively, and to form a more efficient magnetic circuit.

  In the present invention, the thickness of the magnetic plate is preferably larger than the thickness of the cylindrical portion, and the magnetic plate is preferably disposed so as to contact the inner peripheral surface of the cylindrical portion. If comprised in this way, it will become possible to enlarge the contact area of the internal peripheral surface of a cylinder part, and the outer peripheral end of a magnetic board. Therefore, a magnetic path is easily formed between the magnetic plate and the cylindrical portion, and the permeance coefficient of the driving magnet portion can be increased. As a result, it is possible to prevent the magnetic flux density generated by the driving magnet portion from decreasing in a high temperature environment.

  In the present invention, the magnetic plate is preferably formed with an insertion hole through which the movable body is inserted. In this case, the shape of the insertion hole is preferably similar to the outer shape of the movable body. If comprised in this way, it will become possible to make the clearance gap between a movable body and a magnetic board substantially constant. Therefore, the movable range of the movable body in the direction orthogonal to the optical axis direction can be appropriately regulated using the magnetic plate. In addition, scattering of dust generated by the drive mechanism to the image sensor side can be effectively suppressed by the magnetic plate.

  In the present invention, the lens driving device is formed, for example, so that the shape when viewed from the optical axis direction is a substantially square shape, and the driving magnet portion is formed in a substantially triangular prism shape and has four corners of the lens driving device. The drive coil is wound in a substantially triangular tube shape, and the magnetic plate has four substantially triangular cover portions that abut each of one end surfaces of the four drive magnet portions, and a cover portion. And four connecting portions for connecting the two. In this case, it is possible to dispose the driving magnet unit and the driving coil at the four corners of the lens driving device that is likely to become a dead space. Therefore, it is possible to further reduce the size of the lens driving device formed so that the shape when viewed from the optical axis direction is a substantially square shape.

  In the present invention, the lens driving device is formed, for example, so that the shape when viewed from the optical axis direction is a substantially rectangular shape, and the driving magnet portion is formed in a substantially rectangular column shape and viewed from the optical axis direction. Are disposed on both sides of the lens driving device in a direction substantially parallel to the long side of the lens driving device, the driving coil is wound in a substantially rectangular tube shape, and the magnetic plate is composed of two driving magnet portions. Two cover portions each having a substantially square shape that abuts on each of the one end faces, and two connection portions that connect the cover portions are provided. In this case, it is possible to further reduce the size of the lens driving device in a direction substantially parallel to the short side of the lens driving device when viewed from the optical axis direction.

  In the present invention, the drive magnet portion includes two drive magnet pieces arranged so as to overlap in the optical axis direction, and the opposing surfaces of the two drive magnet pieces in the optical axis direction are the same. It is preferable that the magnetic pole is magnetized. If comprised in this way, between the opposing surfaces of two drive magnet pieces, the density of the magnetic flux which passes a drive coil can be raised. Therefore, a magnetic circuit for driving the movable body can be formed more efficiently, and the drive magnet portion and the drive coil can be further reduced in size.

  As described above, according to the present invention, it is possible to reduce the size of the lens driving device while securing the driving force for driving the lens.

It is a perspective view of the lens drive device concerning an embodiment of the invention. It is sectional drawing of the EE cross section of FIG. It is a disassembled perspective view of the lens drive device shown in FIG. FIG. 4 is an enlarged perspective view of a sleeve and a driving coil shown in FIG. 3. It is a perspective view for demonstrating the arrangement | positioning relationship of the drive magnet part and drive coil which are shown in FIG. FIG. 6 is a side view of the drive magnet unit and the drive coil shown in FIG. 5. It is a figure which shows a drive magnet piece and a drive coil from the HH direction of FIG. It is a figure for demonstrating the magnetization state of the magnet part for a drive arrange | positioned at the four corners of the lens drive device of FIG. FIG. 3 is a bottom view showing a sleeve, a first case body, and a magnetic plate shown in FIG. 2 from the side opposite to the subject. FIG. 3 is a plan view showing a sleeve and a driving coil shown in FIG. 2 from a subject side. It is a disassembled perspective view for demonstrating the structure of a part of lens drive device concerning other embodiment of this invention. FIG. 12 is a plan view showing the sleeve, the driving magnet unit, the driving coil, and the magnetic plate shown in FIG. 11 from the subject side.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Schematic configuration of lens driving device)
FIG. 1 is a perspective view of a lens driving device 1 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line EE of FIG. FIG. 3 is an exploded perspective view of the lens driving device 1 shown in FIG. FIG. 4 is an enlarged perspective view of the sleeve 8 and the driving coil 18 shown in FIG. FIG. 5 is a perspective view for explaining the positional relationship between the drive magnet unit 17 and the drive coil 18 shown in FIG.

  The lens driving device 1 of this embodiment is used in a relatively small camera mounted on a mobile phone or the like. That is, the lens driving device 1 is mounted and used in a portable device such as a cellular phone. As shown in FIG. 1, the lens driving device 1 is formed in a substantially quadrangular prism shape as a whole. That is, the lens driving device 1 is formed so that the shape of the lens for photographing when viewed from the direction of the optical axis L (optical axis direction) is a substantially square shape. In this embodiment, the lens driving device 1 is formed so that the shape when viewed from the optical axis direction is substantially square.

  In the camera in which the lens driving device 1 of this embodiment is mounted, an image sensor (not shown) is arranged on the lower side (that is, the Z2 direction side) of FIG. 2, and the upper side (that is, the Z1 direction side) of FIG. The subject placed in is photographed. Therefore, in the following description, the Z1 direction side is the subject side (object side), and the Z2 direction side is the anti-subject side (imaging element side). In the following description, two directions orthogonal to the optical axis L and orthogonal to each other are defined as an X direction and a Y direction. A plane formed from the X direction and the Y direction is defined as an XY plane. In this embodiment, the four side surfaces of the lens driving device 1 are parallel to the X direction or the Y direction.

  As shown in FIGS. 1 and 2, the lens driving device 1 includes a movable body 2 that holds a photographing lens and is movable in the optical axis direction, and a fixed body that holds the movable body 2 so as to be movable in the optical axis direction. 3 and a drive mechanism 4 for driving the movable body 2 in the optical axis direction. The movable body 2 is movably held by the fixed body 3 via two types of plate springs 5 and 6 (see FIG. 3). In addition, illustration of the leaf | plate springs 5 and 6 is abbreviate | omitted in FIG.

  The movable body 2 is fixed by electrically connecting a sleeve 8 that holds a lens holder 7 to which a plurality of lenses are fixed and an end of a driving coil 18 that constitutes the driving mechanism 4 by soldering or the like. Coil end fixing members 9 and 10. 2, illustration of the coil end fixing members 9 and 10 is omitted, and illustration of the lens holder 7 is omitted in FIG.

  The lens holder 7 is formed in a substantially cylindrical shape, and a plurality of lenses having a substantially circular shape when viewed from the optical axis direction are fixed to the inner peripheral side thereof. In this embodiment, a small-diameter lens having a small diameter is disposed on the subject side of the lens holder 7, and a large-diameter lens having a larger diameter than the small-diameter lens is disposed on the non-subject side. Therefore, as shown in FIG. 2, the outer diameter of the lens holder 7 on the subject side is smaller than the outer diameter on the opposite subject side.

  The sleeve 8 is formed in a substantially cylindrical shape, and holds the lens holder 7 on the inner peripheral side thereof. In this embodiment, since the outer diameter on the subject side of the lens holder 7 is smaller than the outer diameter on the opposite subject side, the outer diameter on the subject side of the sleeve 8 is smaller than the outer diameter on the opposite subject side. Further, in this embodiment, the anti-subject side of the sleeve 8 is formed so that the shape when viewed from the optical axis direction is a substantially octagonal shape.

  As shown in FIG. 4, on the outer periphery of the sleeve 8, a fixing surface 8 a for fixing a driving coil 18 (described later) constituting the driving mechanism 4, and a mounting surface 8 b on which the driving coil 18 is mounted. Is formed. The fixed surface 8a is formed in a planar shape parallel to the optical axis L, and is formed at four locations with a pitch of approximately 90 ° around the optical axis L. The placement surface 8b is formed in a planar shape parallel to the XY plane, and is formed at four positions with a substantially 90 ° pitch about the optical axis L. Further, the mounting surface 8b is formed so as to spread outward in the radial direction of the sleeve 8 from the non-subject side end of the fixed surface 8a.

  The coil end fixing members 9 and 10 are made of a conductive metal material. The coil end fixing members 9 and 10 are fixed to the end surface of the sleeve 8 on the side opposite to the subject.

  The fixed body 3 includes a first case body 11 as a case body arranged on the subject side, and a second case body 12 arranged on the opposite subject side.

  The first case body 11 is formed of a magnetic material, and is formed in a substantially rectangular tube shape with a bottom (substantially bottomed rectangular tube shape) having a bottom portion 11a and a tube portion 11b. The first case body 11 of this embodiment is formed by, for example, drawing, and the thickness of the cylindrical portion 11b is thinner than the thickness of the bottom portion 11a. For example, the thickness of the bottom part 11a is 0.15 mm, and the thickness of the cylinder part 11b is 0.1 to 0.12 mm. The first case body 11 is disposed so as to surround the outer peripheral side on the subject side of the drive mechanism 4 and the movable body 2.

  A circular through hole 11c is formed at the center of the bottom 11a disposed on the subject side. Cutout portions 11d are formed at the four corners of the cylindrical portion 11b on the non-subject side, and extending portions 11e extending toward the non-subject side are formed between the cutout portions 11d of the cylindrical portion 11b. The notch portion 11d is formed so as to be recessed from the opposite end of the cylindrical portion 11b toward the subject side. Each of the four side surfaces 11f constituting the cylindrical portion 11b includes two end surfaces 11g of the extending portion 11e substantially parallel to the optical axis direction, and a subject side end of the end surface 11g parallel to the X direction or the Y direction. Two end surfaces 11 h toward the four corners of the first case body 11 are formed.

  The second case body 12 is formed of a resin material and is formed in a substantially rectangular tube shape. As shown in FIG. 3, a terminal 13 is fixed to the second case body 12. Further, the second case body 12 has a contact surface 12a (see FIG. 2) with which the end surface of the sleeve 8 on the side opposite to the subject contacts, and an attachment recess 12b for attaching the lens driving device 1 to a portable device such as a cellular phone. (Refer FIG. 3) and the arrangement | positioning recessed part 12c (refer FIG. 3) in which the extension part 11e of the 1st case body 11 is arrange | positioned are formed.

  The contact surface 12a is formed in parallel with the XY plane. The attachment recesses 12 b are formed on the outer peripheral surfaces of the four corners of the second case body 12. The mounting recess 12b is formed to comply with, for example, the SMIA (Standard Mobile Imaging Architecture) standard. Specifically, the mounting recess 12b is directed from the side surface of the second case body 12 parallel to the Y direction to the inside of the X direction. It is formed to be depressed. The arrangement | positioning recessed part 12c is formed so that it may become depressed toward the X direction inner side or the Y direction inner side from the four side surfaces of the 2nd case body 12. FIG. Moreover, the arrangement | positioning recessed part 12c is formed in the center part of the side surface of the 2nd case body 12 in a X direction or a Y direction, and is formed so that it may not connect with the attachment recessed part 12b.

  The second case body 12 is attached to the anti-subject side of the first case body 11 so as to cover the outer peripheral side of the lens holder 7 on the anti-subject side. That is, the first case body 11 and the second case body 12 are combined in the optical axis direction. Specifically, the first case body 11 and the second case body 12 are combined and fixed so that the extending portion 11e of the first case body 11 is arranged in the arrangement recess 12c of the second case body 12. ing. That is, the first case body 11 and the second case body 12 are combined and fixed so that the extending portion 11e overlaps the outer peripheral surface of the second case body 12 from the outside. The first case body 11 and the second case body 12 are combined and fixed so that the subject-side end face 12d of the second case body 12 and the end face 11h of the first case body 11 come into contact with each other.

  The leaf spring 5 includes a sleeve fixing portion that is fixed to the sleeve 8, a case body fixing portion that is fixed to the first case body 11, and a spring portion that connects the sleeve fixing portion and the case body fixing portion. It is arranged on the subject side of the body 2. The sleeve fixing portion is fixed to the end surface of the sleeve 8 on the subject side. The case body fixing portion is fixed to the surface on the side opposite to the subject of the bottom portion 11a of the first case body 11 via a spacer 14 formed in a substantially rectangular frame shape. That is, the case body fixing portion is fixed to the spacer 14 fixed to the surface of the bottom portion 11a on the side opposite to the subject.

  The leaf spring 6 includes a sleeve fixing portion fixed to the sleeve 8, a case body fixing portion fixed to the second case body 12, and a spring portion connecting the sleeve fixing portion and the case body fixing portion. Arranged on the opposite side of the body 2. The sleeve fixing portion is fixed to the end surface of the sleeve 8 on the side opposite to the subject via the coil end fixing members 9 and 10. That is, the sleeve fixing portion is fixed to the coil end fixing members 9 and 10. The case body fixing portion is fixed to a fixing surface formed on the subject side of the second case body 12.

  As shown in FIGS. 2, 5, and the like, the drive mechanism 4 includes four substantially triangular prism-shaped drives disposed at the four corners of the lens drive device 1 (specifically, the four corners inside the first case body 11). Four driving coils 18 wound in a substantially triangular tube shape, the inner peripheral side of which is disposed opposite to the outer peripheral surface of the driving magnet unit 17 with a predetermined gap, and the driving coil A magnetic member 19 that is fixed to the movable body 2 on the subject side with respect to 18, coil protection members 20 and 21 that are attached to the subject side and the non-subject side of the drive coil 18, and an anti-subject side of the drive magnet unit 17. And a magnetic plate 22 to be arranged. Hereinafter, a detailed configuration of the drive mechanism 4 will be described.

(Configuration of drive mechanism)
6 is a side view of the drive magnet unit 17 and the drive coil 18 shown in FIG. FIG. 7 is a diagram illustrating the driving magnet piece 24 and the driving coil 18 from the HH direction in FIG. 6. FIG. 8 is a diagram for explaining a magnetized state of the driving magnet unit 17 disposed at the four corners of the lens driving device 1 of FIG. FIG. 9 is a bottom view showing the sleeve 8, the first case body 11, and the magnetic plate 22 shown in FIG. FIG. 10 is a plan view showing the sleeve 8 and the drive coil 18 shown in FIG. 2 from the subject side.

  As described above, the drive magnet portions 17 are arranged at the four corners inside the first case body 11. That is, the driving magnet unit 17 is disposed on the outer peripheral side of the movable body 2. The drive magnet portion 17 is a plate-like plate disposed between the two substantially triangular prism-shaped drive magnet pieces 23 and 24 arranged so as to overlap in the optical axis direction, and the drive magnet pieces 23 and 24. And a magnetic member 25. The object side surface of the magnetic member 25 is fixed to the end surface of the driving magnet piece 23 on the side opposite to the subject, and the surface of the magnetic member 25 opposite to the object side is fixed to the end surface on the subject side of the driving magnet piece 24. Has been.

  The driving magnet pieces 23 and 24 are formed so that the shape when viewed from the optical axis direction is a substantially right-angled isosceles triangle, and is substantially parallel to the optical axis L as shown in FIGS. And two orthogonal surface portions 23a, 24a that are orthogonal to each other, and one rectangular inclined surface portion 23b, 24b that is substantially parallel to the optical axis L and connects the two orthogonal surface portions 23a, 24a. Yes.

  The driving magnet pieces 23 and 24 are arranged such that the inner peripheral surface of the cylindrical portion 11b of the first case body 11 and the orthogonal surface portions 23a and 24a are substantially parallel to each other. That is, the two drive magnet pieces 23 and 24 arranged at diagonal positions inside the first case body 11 are arranged such that the slope portions 23b and 24b face each other. Further, the four drive magnet pieces 23 are fixed to the bottom portion 11 a of the first case body 11. Specifically, the subject-side end surfaces of the four drive magnet pieces 23 are fixed to the surface of the bottom portion 11a on the side opposite to the subject by bonding or the like. Yes. Further, the end faces on the subject side of the four drive magnet pieces 23 are completely covered by the bottom 11a.

  The magnetic member 25 is made of a magnetic material. The magnetic member 25 is formed in a flat plate shape having a substantially right-angled isosceles triangle shape similar to that of the drive magnet pieces 23 and 24 when viewed from the optical axis direction.

  The magnetic plate 22 is formed of a magnetic material and has a flat plate shape. Further, the magnetic plate 22 is formed by, for example, pressing. The thickness of the magnetic plate 22 is substantially the same as the thickness of the bottom portion 11 a of the first case body 11. That is, the thickness of the magnetic plate 22 is thicker than the thickness of the cylindrical portion 11 b of the first case body 11. The magnetic plate 22 includes four cover portions 22a each having a substantially triangular shape that covers the end surfaces of the four drive magnet portions 17 on the side opposite to the subject (specifically, the end surfaces of the drive magnet pieces 24). It is comprised from the four connection parts 22b which connect the piece cover parts 22a. That is, in this embodiment, the four cover portions 22a are integrated by the connection portion 22b.

  The cover 22a is formed so that the shape when viewed from the optical axis direction is a substantially right-angled isosceles triangle. Specifically, the cover 22 a is formed so that the shape when viewed from the optical axis direction is a substantially right-angled isosceles triangle having a larger outer shape than the drive magnet 17. The connecting portion 22b is formed in an elongated rectangular shape, and is arranged so as to be parallel to the X direction or the Y direction. The connecting portion 22 b connects the cover portions 22 a adjacent to each other in the circumferential direction of the lens driving device 1 on the outer peripheral end side of the magnetic plate 22, and the sleeve 8 is inserted through the center of the magnetic plate 22. The hole 22c is formed so as to penetrate in the optical axis direction. The insertion hole 22c is formed in a substantially octagonal shape that is larger than the outer shape of the substantially octagonal sleeve 8 on the side opposite to the subject. That is, as shown in FIG. 9, the shape of the insertion hole 22 c is similar to the outer shape of the sleeve 8 on the side opposite to the subject.

  The magnetic plate 22 is fixed to the end surfaces of the four driving magnet pieces 24 on the side opposite to the subject. Specifically, as shown in FIG. 8, the magnetic plate 22 is configured such that the oblique side portion of the cover portion 22 a and the inclined surface portion 24 b of the drive magnet piece 24 are substantially parallel, and the cover portion 22 a is for driving. The magnet pieces 24 are fixed to the four driving magnet pieces 24 by adhesion or the like in contact with the end surface of the magnet piece 24 on the side opposite to the subject. The magnetic plate 22 is fixed to the four driving magnet pieces 24 so that the cover 22a completely covers the end surface of the driving magnet piece 24 on the side opposite to the subject. Moreover, the outer peripheral end of the magnetic plate 22 is in contact with the inner peripheral surface of the cylindrical portion 11b of the first case body 11, as shown in FIG.

  As shown in FIGS. 7 and 10, the driving coil 18 is wound so that the shape when viewed from the optical axis direction is a substantially right-angled isosceles triangle. Two rectangular surface portions 18a that are substantially parallel to the optical axis L and orthogonal to each other, and one rectangular inclined surface portion 18b that is substantially parallel to the optical axis L and connects the two orthogonal surface portions 18a. ing.

  The four drive coils 18 are fixed to the outer peripheral surface of the sleeve 8. Specifically, the inclined surface portion 18b is fixed to the fixed surface 8a by adhesion in a state where the surface of the inclined surface portion 18b opposite to the subject side is mounted on the mounting surface 8b of the sleeve 8. More specifically, the inclined surface portion 18b is arranged so that the inclined surface portion 18b and the fixed surface 8a are substantially parallel and a slight gap is formed between the inclined surface portion 18b and the fixed surface 8a. It is fixed to the fixed surface 8a. Further, the inclined surface portion 18b is fixed to the fixed surface 8a so that the inner peripheral surface of the driving coil 18 and the outer peripheral surface of the driving magnet portion 17 are substantially parallel with a predetermined gap therebetween.

  As described above, in this embodiment, the four drive coils 18 are fixed to the outer peripheral surface of the sleeve 8 at a pitch of approximately 90 °, and the drive coils 18 are arranged at the four corners inside the first case body 11. ing. The drive coil 18 is disposed at four corners inside the first case body 11 with predetermined gaps between the drive coil 18 and the inner peripheral surface of the first case body 11, and together with the sleeve 8, the optical axis. It can move in the direction.

  The width of the drive coil 18 in the optical axis direction is equal to or greater than the thickness of the magnetic member 25. Specifically, the width of the driving coil 18 in the optical axis direction is equal to or greater than the sum of the thickness of the magnetic member 25 and the movable distance of the movable body 2. Further, in this embodiment, the driving magnet unit 17 and the driving coil 18 are arranged so that the magnetic member 25 is always arranged on the inner peripheral side of the driving coil 18 within the movable range of the movable body 2. Yes.

  As shown in FIGS. 6 and 8, the two drive magnet pieces 23 and 24 constituting the drive magnet unit 17 have the same magnetic poles (S pole and S pole, or N pole) in the optical axis direction. N poles) are arranged to face each other. That is, the opposing surfaces of the drive magnet pieces 23 and 24 are both magnetized to the same magnetic pole. Therefore, as shown in FIGS. 6 and 7, a magnetic flux F passing through the orthogonal surface portion 18 a and the inclined surface portion 18 b of the drive coil 18 is generated between the drive magnet pieces 23 and 24. That is, the drive magnet unit 17 is magnetized so that a magnetic flux F passing through the drive coil 18 is generated at a position facing the drive coil 18.

  As shown in FIG. 8, the other two magnetic poles adjacent to each other in the circumferential direction of the lens driving device 1 are formed on the opposing surfaces of the two driving magnet pieces 23 and 24 constituting the driving magnet unit 17. This is different from the magnetic poles formed on the opposing surfaces of the drive magnet pieces 23, 24. For example, the magnetic poles formed on the opposing surfaces of the driving magnet pieces 23 and 24 arranged on the right and left sides in FIG. 8 are S poles, and the driving magnet pieces 23 arranged on the upper and lower sides in FIG. , 24 are N poles. Therefore, in the example shown in FIG. 8, from between the driving magnet pieces 23 and 24 arranged on the upper and lower sides in FIG. 8 to between the driving magnet pieces 23 and 24 arranged on the right and left sides in FIG. A magnetic flux F heading is generated. Note that all of the magnetic poles formed on the opposing surfaces of the two driving magnet pieces 23 and 24 adjacent in the circumferential direction of the lens driving device 1 may be the same magnetic pole.

  The magnetic member 19 is formed of a magnetic material and is formed in a substantially annular shape. The magnetic member 19 is formed in a flat plate shape. In this embodiment, the driving magnet unit 17 and the driving coil 18 are attracted so that the magnetic member 19 is attracted toward the intermediate position of the driving magnet unit 17 in the optical axis direction within the movable range of the movable body 2. Has been placed. Therefore, when no current is supplied to the driving coil 18, the end surface of the sleeve 8 on the side opposite to the subject is first caused by the attractive force generated between the magnetic member 19 and the driving magnet portion 17 as shown in FIG. 2 is in contact with the contact surface 12 a of the case body 12.

  The coil protection members 20 and 21 are formed of a relatively hard resin material or metal material such as PET (polyethylene terephthalate), and are formed in a substantially rectangular frame shape as shown in FIG. The coil protection members 20 and 21 are formed in a flat plate shape. In this embodiment, the coil protection member 20 is attached to the end surface on the subject side of the driving coil 18, and the coil protection member 21 is attached to the end surface on the side opposite to the subject of the driving coil 18.

(Main effects of this form)
As described above, in this embodiment, when viewed from the optical axis direction, the lens driving device 1 having a substantially square shape has substantially triangular prism driving magnet portions 17 and substantially triangular cylindrical driving coils at the four corners. 18 is arranged. For this reason, the driving magnet portions 17 and the driving coils 18 are arranged at the four corners of the lens driving device 1 that becomes a dead space of the lens driving device 1 that drives a lens having a substantially circular shape when viewed from the optical axis direction. be able to.

  In this embodiment, the inner peripheral surface of the driving coil 18 wound in a substantially triangular cylindrical shape is disposed opposite to the outer peripheral surface of the driving magnet portion 17 with a predetermined gap, and the driving magnet portion 17. Is magnetized so that a magnetic flux F passing through the driving coil 18 is generated at a position facing the driving coil 18. Therefore, it is possible to efficiently form a magnetic circuit for driving the movable body 2 using the entire circumference of the drive magnet portion 17 and the entire circumference of the drive coil 18. Therefore, a predetermined driving force for driving the movable body 2 can be obtained even if the driving magnet unit 17 and the driving coil 18 are downsized. That is, in this embodiment, the driving magnet unit 17 and the driving coil 18 can be reduced in size while securing a driving force for driving the movable body 2.

  As described above, in this embodiment, the driving magnet unit 17 and the driving coil 18 can be reduced in size, and the driving magnet unit 17 and the driving coil 18 are provided at the four corners of the lens driving device 1 that becomes a dead space. Can be arranged. Therefore, in this embodiment, the lens driving device 1 can be reduced in size.

  In this embodiment, the opposing surfaces of the two drive magnet pieces 23 and 24 arranged so as to overlap in the optical axis direction are both magnetized to the same magnetic pole. Therefore, the density of the magnetic flux F passing through the driving coil 18 can be increased between the opposing surfaces of the two driving magnet pieces 23 and 24. Therefore, the magnetic circuit for driving the movable body 2 can be formed more efficiently, and the drive magnet portion 17 and the drive coil 18 can be further reduced in size.

  In this embodiment, the subject-side end surfaces of the four drive magnet portions 17 are covered with the bottom portion 11a of the case body 11 and are in contact with the bottom portion 11a. Further, the end surfaces on the side opposite to the subject of the four drive magnet portions 17 are covered with the cover portion 22a of the magnetic plate 22 and are in contact with the cover portion 22a. Therefore, it is possible to suppress the leakage of the magnetic flux F generated by the driving magnet unit 17 to the outside of the lens driving device 1 and form an efficient magnetic circuit.

  In this embodiment, four cover portions 22a are integrated. Therefore, the number of parts can be reduced and the magnetic properties can be reduced as compared with the case where the four cover portions 22a are formed separately (that is, when the four cover portions 22a are not integrated). Even if the plate 22 is downsized, the magnetic plate 22 can be easily handled when the lens driving device 1 is manufactured. Further, when the four cover portions 22a are formed as separate bodies, it becomes difficult to ensure the flatness and parallelism of the four cover portions 22a. Since the part 22a is composed of an integrated part, it becomes easy to ensure the flatness and parallelism of the four cover parts 22a in a uniform state. In this embodiment, the flatness and parallelism of the four cover portions 22a can be easily ensured in a uniform state, so that the surface of the magnetic plate 22 on the side opposite to the subject contacts the second case body 12. When the contact surface is formed, the bottom 11a of the case body 11 and the drive magnet portion 17, the drive magnet portion 17 and the magnetic plate 22, and the contact surface of the magnetic plate 22 and the second case body 12 are defined. It is possible to make contact with high accuracy.

  Further, since the four cover portions 22a are integrated, when both end surfaces of the four drive magnet portions 17 are fixed to the first case body 11 and the magnetic plate 22, the mechanical function of the lens driving device 1 is achieved. Increase in strength. Therefore, the impact resistance at the time of the drop impact of the lens driving device 1 can be enhanced.

  In this embodiment, the thickness of the magnetic plate 22 is thicker than the thickness of the cylindrical portion 11 b of the first case body 11. Therefore, it is possible to increase the contact area between the inner peripheral surface of the cylindrical portion 11 b of the first case body 11 and the outer peripheral end of the magnetic plate 22. Therefore, a magnetic path is easily formed between the magnetic plate 22 and the cylindrical portion 11b, and the permeance coefficient of the driving magnet portion 17 can be increased. As a result, in this embodiment, it is possible to suppress the density of the magnetic flux F generated by the driving magnet unit 17 from decreasing in a high temperature environment. In particular, in this embodiment, since the four cover portions 22a are integrated, a magnetic path is more easily formed between the magnetic plate 22 and the cylindrical portion 11b, and the permeance coefficient of the driving magnet portion 17 is further increased. It becomes possible to do.

  In this embodiment, the magnetic plate 22 includes four cover portions 22a that cover the respective end surfaces on the side opposite to the subject of the four drive magnet pieces 24, and four connection portions 22b that connect the four cover portions 22a. It is composed of Therefore, as compared with the case where the four cover portions 22a are formed separately, foreign matters such as dust generated by the drive mechanism 4 enter the opposite side of the lens drive device 1 on which the image pickup device or the like is disposed. This can be suppressed by the magnetic plate 22. In particular, in the present embodiment, the shape of the insertion hole 22c of the magnetic plate 22 is similar to the outer shape of the sleeve 8 on the side opposite to the subject. It is possible to effectively suppress intrusion into the opposite subject side.

  In this embodiment, the shape of the insertion hole 22c of the magnetic plate 22 is similar to the outer shape of the sleeve 8 on the side opposite to the subject. For this reason, the gap between the sleeve 8 and the magnetic plate 22 can be made substantially constant. Therefore, the movable range of the movable body 2 in the direction orthogonal to the optical axis direction can be appropriately regulated using the magnetic plate 22.

(Other embodiments)
The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention.

  In the embodiment described above, the lens driving device 1 is formed so that the shape when viewed from the optical axis direction is substantially square. Further, a drive magnet portion 17 formed in a substantially triangular prism shape and a drive coil 18 wound in a substantially triangular tube shape are arranged at the four corners of the lens driving device 1. In addition, for example, the lens driving device 1 may be formed so that the shape when viewed from the optical axis direction is substantially rectangular.

  When the lens driving device 1 is formed so that the shape when viewed from the optical axis direction is substantially rectangular, as shown in FIGS. 11 and 12, the driving magnet portion 57 has a substantially square shape. Formed in a columnar shape and disposed on both sides of the lens driving device 1 in a direction substantially parallel to the long side of the lens driving device 1 when viewed from the optical axis direction, the driving coil 58 is wound in a substantially rectangular tube shape. May be. In this case, the magnetic plate 62 includes, for example, two substantially square-shaped cover parts 62a that come into contact with each other so as to cover the end surfaces on the opposite object side of the two drive magnet parts 57, and the cover parts 62. It is comprised by the two long and thin rectangular connection parts 62b to connect. The magnetic plate 62 is formed with an insertion hole 62c through which the sleeve 48 for holding the lens holder 7 is inserted so as to penetrate in the optical axis direction. In this case, the sleeve 48 is formed in a substantially rectangular tube shape as a whole, and the shape of the insertion hole 62 c is similar to the outer shape of the sleeve 48. In addition, the drive magnet portion 57 includes two substantially quadrangular columnar drive magnet pieces 63 and 64 arranged so as to overlap in the optical axis direction, and a magnetic member arranged between the drive magnet pieces 63 and 64. 65.

  Further, the lens driving device 1 may be formed so that the shape when viewed from the optical axis direction is a substantially polygonal shape other than the substantially square shape, or the shape when viewed from the optical axis direction is a substantially circular shape. Or you may form so that it may become a substantially ellipse shape.

  In the embodiment described above, the drive magnet portion 17 is formed in a substantially triangular prism shape, and the drive coil 18 is wound in a substantially triangular tube shape. In addition, for example, the drive magnet portion 17 may be formed in a substantially polygonal column shape other than the substantially triangular prism shape, and the drive coil 18 may be formed in a substantially polygonal tube shape other than the substantially triangular tube shape. Further, the drive magnet portion 17 may be formed in a substantially columnar shape or a substantially elliptical column shape, and the drive coil 18 may be formed in a substantially cylindrical shape or a substantially elliptical cylinder shape.

  In the embodiment described above, the side opposite to the subject of the sleeve 8 is formed in a substantially octagonal shape, and the insertion hole 22c of the magnetic plate 22 is formed in a substantially octagonal shape that is similar to the outer shape of the sleeve 8 on the side opposite to the subject. In addition, for example, the non-subject side of the sleeve 8 may be formed in a substantially circular shape, and the insertion hole 22c may be formed in a substantially circular shape that is similar to the outer shape of the sleeve 8 on the non-subject side. Further, the opposite side of the sleeve 8 is formed in a substantially polygonal shape or a substantially elliptical shape other than a substantially octagonal shape, and the insertion hole 22c is formed in a substantially polygonal shape or a substantially elliptical shape that is similar to the outer shape of the sleeve 8 on the opposite side of the subject. May be. Further, the shape of the insertion hole 22c may not be similar to the outer shape of the sleeve 8 on the side opposite to the subject.

  In the embodiment described above, the magnetic member 25 is disposed between the driving magnet pieces 23 and 24. However, a predetermined gap may be formed between the opposing surfaces of the driving magnet pieces 23 and 24. The opposing surfaces of the drive magnet pieces 23 and 24 may be in contact with each other. In the above-described embodiment, the driving magnet unit 17 is configured by the two driving magnet pieces 23 and 24 and the magnetic member 25. However, the driving magnet unit 17 includes one driving magnet piece. It may be constituted only by. In this case, the driving magnet pieces are magnetized so that the magnetic poles formed at both ends in the optical axis direction are different from the magnetic poles formed at intermediate positions in the optical axis direction. That is, the driving magnet piece is magnetized so that a magnetic flux F passing through the driving coil 18 is generated at a position facing the driving coil 18.

  In the embodiment described above, the driving magnet unit 17 and the driving coil 18 are disposed at the four corners of the lens driving device 1. In addition to this, for example, if the driving force of the movable body 2 can be obtained, the driving magnet portion 17 and the driving coil 18 are arranged only at three, two, or one corner of the lens driving device 1. May be. In this case, a guide shaft for guiding the movable body 2 in the optical axis direction is arranged at the corner of the lens driving device 1 where the driving magnet portion 17 and the driving coil 18 are not arranged, and is engaged with this guide shaft. An engaging recess may be formed in the sleeve 8.

  In the embodiment described above, the drive coil 18 is fixed to the movable body 2 side and the drive magnet portion 17 is fixed to the fixed body 3 side. However, the drive magnet portion 17 is fixed to the movable body 2 side and fixed. The driving coil 18 may be fixed to the body 3 side. In the embodiment described above, the cover 22a completely covers the end surface of the drive magnet unit 17 on the side opposite to the subject, but the cover 22a is a part of the end surface of the drive magnet unit 17 on the side opposite to the subject. You may only cover.

DESCRIPTION OF SYMBOLS 1 Lens drive device 2 Movable body 4 Drive mechanism 11 1st case body (case body)
11a Bottom portion 11b Tube portion 17, 57 Driving magnet portion 18, 58 Driving coil 22, 62 Magnetic plate 22a, 62a Cover portion 22b, 62b Connection portion 22c, 62c Insertion hole 23, 24, 63, 64 Driving magnet piece F Magnetic flux L Optical axis

Claims (8)

A movable body that holds the lens and is movable in the optical axis direction of the lens, and a drive mechanism for driving the movable body in the optical axis direction;
The drive mechanism is wound in a substantially cylindrical shape with a plurality of substantially columnar drive magnet portions disposed on the outer peripheral side of the movable body, and an inner peripheral surface of the drive mechanism is predetermined with respect to the outer peripheral surface of the drive magnet portion. A driving coil disposed oppositely through a gap, and a magnetic plate formed of a magnetic material and disposed on one end side of the driving magnet portion in the optical axis direction,
The drive magnet portion is magnetized so that a magnetic flux passing through the drive coil is generated at a position facing the drive coil,
The magnetic plate includes a plurality of cover portions covering each of one end surfaces of the plurality of drive magnet portions,
A plurality of said cover parts are integrated, The lens drive device characterized by the above-mentioned. A case body formed of a magnetic material and disposed so as to surround the movable body and the drive mechanism;
The case body is disposed so as to surround a bottom portion that contacts the other end surface of the drive magnet portion so as to cover the other end surfaces of the plurality of drive magnet portions, and an outer peripheral side of the movable body and the drive mechanism. Formed in a substantially bottomed cylindrical shape with a cylindrical portion,
The lens driving device according to claim 1, wherein the cover is in contact with one end surface of the driving magnet. The thickness of the magnetic plate is thicker than the thickness of the cylindrical portion,
The lens driving device according to claim 2, wherein the magnetic plate is disposed so as to contact an inner peripheral surface of the cylindrical portion.   The lens driving device according to claim 1, wherein an insertion hole through which the movable body is inserted is formed in the magnetic plate.   The lens driving device according to claim 4, wherein a shape of the insertion hole is similar to an outer shape of the movable body. The lens driving device is formed so that the shape when viewed from the optical axis direction is a substantially square shape,
The driving magnet portion is formed in a substantially triangular prism shape and disposed at the four corners of the lens driving device,
The driving coil is wound in a substantially triangular tube shape,
The magnetic plate includes four substantially triangular cover parts that abut each of one end surfaces of the four drive magnet parts, and four connection parts that connect the cover parts. The lens driving device according to claim 1. The lens driving device is formed so that the shape when viewed from the optical axis direction is a substantially rectangular shape,
The driving magnet portion is formed in a substantially quadrangular prism shape and disposed on both sides of the lens driving device in a direction substantially parallel to a long side of the lens driving device when viewed from the optical axis direction.
The driving coil is wound in a substantially rectangular tube shape,
The magnetic plate includes two substantially quadrangular cover parts that abut each of one end surfaces of the two drive magnet parts, and two connection parts that connect the cover parts. The lens driving device according to claim 1. The drive magnet portion includes two drive magnet pieces arranged to overlap in the optical axis direction,
The lens driving device according to any one of claims 1 to 7, wherein the opposing surfaces of the two driving magnet pieces in the optical axis direction are both magnetized by the same magnetic pole.

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