JP5214425B2 - Lens drive device - Google Patents

Description

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

  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 body through two leaf springs There is known a lens driving device including a fixed body that is movably held (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 used for mobile phones and the like, there has been an increasing demand for miniaturization of cameras, and therefore, there has been an increasing demand for miniaturization of lens driving devices mounted on cameras. On the other hand, in recent years, in the market of cameras used for mobile phones and the like, there is an increasing demand for higher pixels and higher resolution, and the diameter of lenses mounted on lens driving devices tends to increase. Therefore, it is difficult to reduce the size of the lens driving device.

  Accordingly, an object of the present invention is to reduce the size of a lens driving device having a substantially square shape when viewed from the optical axis direction of the lens even when the diameter of the mounted lens is increased. It is an object of the present invention to provide a lens driving device capable of satisfying the requirements.

  In order to solve the above problems, the lens driving device of the present invention is a lens driving device having a substantially square shape when viewed from the optical axis direction of the lens, and is capable of holding the lens and moving in the optical axis direction. A movable body, and a drive mechanism for driving the movable body in the optical axis direction. The drive mechanism includes a substantially triangular prism-shaped drive magnet portion disposed at at least one of the four corners of the lens drive device, A driving coil that is wound in a triangular cylinder and has an inner circumferential surface facing the outer circumferential surface of the driving magnet unit with a predetermined gap therebetween, and the driving magnet unit is opposed to the driving coil. It is magnetized so as to generate a magnetic flux that passes through the drive coil at a position.

  In the lens driving device of the present invention, driving magnet portions having substantially triangular prism shapes are arranged at the four corners of the lens driving device having a substantially square shape when viewed from the optical axis direction of the lens. Further, the driving coil wound in a substantially triangular cylindrical shape is arranged so that the inner peripheral side thereof faces the outer peripheral surface of the driving magnet part with a predetermined gap. Therefore, 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 dead space.

  Further, in the present invention, the inner peripheral surface of the driving coil wound in a substantially triangular 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 driven 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. That is, it is possible to reduce the size of the driving magnet portion and the driving coil while securing a driving force for driving the movable body.

  As described above, in the present invention, the driving magnet portion and the driving coil can be reduced in size, and the driving magnet and the driving coil can be arranged at the four corners of the lens driving device that is likely to become a dead space. Therefore, in the present invention, the lens driving device can be reduced in size even when the diameter of the mounted lens is increased.

  In the present invention, the drive magnet portion includes two substantially triangular prism-shaped 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 Both are preferably magnetized on the same magnetic pole. 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.

  In the present invention, for example, a gap is formed between two drive magnet pieces in the optical axis direction. In the present invention, the drive magnet portion preferably includes a magnetic plate formed of a magnetic material and disposed between two drive magnet pieces in the optical axis direction. According to the study of the present inventor, when a magnetic plate is disposed between two drive magnet pieces, it is possible to effectively increase the density of magnetic flux passing through the drive coil.

  In the present invention, the width of the driving coil in the optical axis direction is equal to or greater than the sum of the distance between the opposing surfaces of the driving magnet pieces facing each other in the optical axis direction and the movable distance of the movable body. preferable. With this configuration, the density of the magnetic flux passing through the drive coil can be made uniform at any position in the optical axis direction within the movable range of the movable body. Therefore, the driving force of the movable body can be stabilized within the movable range of the movable body.

  In the present invention, the driving magnet portions are arranged at the four corners of the lens driving device, and the magnetic poles formed at the intermediate positions in the optical axis direction of the driving magnet portion are adjacent to other driving devices in the circumferential direction of the lens driving device. It is preferable that the magnetic part is different from the magnetic pole formed at an intermediate position in the optical axis direction of the magnet part. In the present invention, the driving magnet portions are arranged at the four corners of the lens driving device, and the magnetic poles formed on the opposing surfaces of the two driving magnet pieces are adjacent to each other in the circumferential direction of the lens driving device. It is preferable that the magnetic poles are different from the magnetic poles formed on the opposing surfaces of the two drive magnet pieces. If comprised in this way, it will become possible to form an efficient magnetic circuit between the drive magnet parts adjacent in the circumferential direction of a lens drive device.

  In the present invention, it is preferable that the lens driving device includes a substantially square cylindrical case body formed of a magnetic material and disposed so as to surround the movable body and the driving mechanism. In the present invention, the lens driving device includes a subject-side magnetic member formed of a magnetic material and in contact with an end surface on the subject side of the driving magnet portion, and an end surface on the side opposite to the subject of the driving magnet portion formed of a magnetic material. It is preferable to provide an anti-subject side magnetic member that abuts. If comprised in this way, it will become possible to suppress the leakage of the magnetic flux which a drive magnet part generates, and to form an efficient magnetic circuit.

  In the present invention, the movable body includes a substantially cylindrical sleeve in which the lens is disposed on the inner peripheral side, and the sleeve is disposed on the subject side and the outer diameter of the small diameter portion disposed on the anti-subject side. It is preferable that the driving coil is fixed to the outer peripheral surface of the small diameter portion. If comprised in this way, compared with the case where the drive coil is being fixed to the outer peripheral surface of a large diameter part, it will become possible to arrange | position a drive magnet part in the position nearer to a sleeve. Therefore, it is possible to further reduce the size of the lens driving device.

  In the present invention, the driving magnet portion and the driving coil are arranged at the four corners of the lens driving device, and the four driving coils are formed by, for example, sequentially winding one conductive wire. In this case, the number of power supply terminals for supplying current to the four drive coils can be minimized, and the configuration of the lens drive device can be simplified.

  In the present invention, the driving magnet section and the driving coil may be arranged at the four corners of the lens driving device, and the four driving coils may be formed by winding four conductive wires. In this case, it is possible to individually supply current to the four driving coils. Therefore, it is possible to correct the tilt of the lens held by the movable body by controlling the direction and current value of the current supplied to the four drive coils.

  As described above, according to the present invention, in the lens driving device in which the shape when viewed from the optical axis direction of the lens is a substantially square shape, even when the diameter of the mounted lens is increased, the lens driving device Can be miniaturized.

  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 a main part of the lens driving device 1 shown in FIG.

  The lens driving device 1 of this embodiment is mounted on a relatively small camera used in a mobile phone or the like, and is formed in a substantially quadrangular prism shape as a whole as shown in FIG. 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 according to this embodiment is mounted, an image sensor (not shown) is arranged on the lower side in FIG. 2 (that is, the Z2 direction side), and the upper side in FIG. 2 (that is, the Z1 direction). The subject placed on the side) is photographed. Therefore, in the following description, the Z1 direction side is the subject side, and the Z2 direction side is the anti-subject side (imaging element side).

  As shown in FIGS. 1 to 3, 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 includes a sleeve 6 that holds a lens holder 5 to which a plurality of lenses are fixed. The lens holder 5 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 periphery thereof. The sleeve 6 is formed in a substantially cylindrical shape, and holds the lens holder 5 on 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 5, 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 on the subject side of the lens holder 5 is smaller than the outer diameter on the opposite subject side. Further, since the outer diameter on the subject side of the lens holder 5 is smaller than the outer diameter on the opposite subject side, the sleeve 6 is opposite to the small diameter portion 6a disposed on the subject side as shown in FIG. It is formed in a substantially cylindrical shape with a step that is arranged on the object side and is composed of a large diameter portion 6b having an inner diameter and an outer diameter larger than those of the small diameter portion 6a.

  A male screw is formed on the outer peripheral surface of the lens holder 5, and a female screw that engages with the male screw formed on the outer peripheral surface of the lens holder 5 is formed on the inner peripheral surface of the sleeve 6. A part of a leaf spring (not shown) is fixed to the subject side end and the non-subject side end of the sleeve 6. Another part of the leaf spring is fixed to the fixed body 3, and the movable body 2 is held by the fixed body 3 via the leaf spring.

  The fixed body 3 includes a first case body 7 disposed on the subject side and a second case body 8 disposed on the opposite subject side. The first case body 7 is formed of a magnetic material, and is formed in a substantially square cylindrical shape with a bottom having a bottom portion 7a and a cylindrical portion 7b. A circular through hole 7c is formed at the center of the bottom 7a arranged on the subject side. The first case body 7 is disposed so as to surround the outer peripheral side of the movable body 2 and the drive mechanism 4. For example, the second case body 8 is formed of a resin material and is formed in a substantially rectangular tube shape. The second case body 8 is attached to the anti-subject side end of the first case body 7 so as to cover the outer peripheral side of the lens holder 5 on the anti-subject side.

  The drive mechanism 4 includes four substantially triangular prism-shaped drive magnet portions 11 disposed at four corners of the lens drive device 1 (specifically, four corners inside the first case body 7), and a substantially triangular cylindrical shape. Four driving coils 12 that are wound and whose inner peripheral side is arranged to face the outer peripheral surface of the driving magnet unit 11 with a predetermined gap are provided. Hereinafter, a detailed configuration of the drive mechanism 4 will be described.

(Configuration of drive mechanism)
4 is a side view of the drive magnet unit 11 and the drive coil 12 shown in FIG. FIG. 5 is a diagram illustrating the driving magnet piece 14 and the driving coil 12 from the GG direction of FIG. 4. FIG. 6 is a diagram for explaining the magnetized state of the driving magnet unit 11 disposed at the four corners of the lens driving device 1 of FIG.

  The drive magnet unit 11 includes two drive magnet pieces 13 and 14 each having a substantially triangular prism shape arranged so as to overlap in the optical axis direction. In this embodiment, the driving magnet piece 13 is disposed on the subject side, and the driving magnet piece 14 is disposed on the opposite subject side. The driving magnet piece 13 and the driving magnet piece 14 are arranged with a predetermined gap in the optical axis direction. That is, a predetermined gap is formed between the driving magnet piece 13 and the driving magnet piece 14 in the optical axis direction.

  The drive magnet pieces 13 and 14 are formed so that the shape when viewed from the optical axis direction is a substantially right-angled isosceles triangle, and is parallel to the optical axis L as shown in FIGS. Two rectangular plane portions 13a and 14a orthogonal to each other and one rectangular slope portion 13b and 14b parallel to the optical axis L and connecting the two plane portions 13a and 14a are provided. In this embodiment, the driving magnet pieces 13 and 14 are arranged so that the inner peripheral surface of the cylindrical portion 7b of the first case body 7 and the flat portions 13a and 14a are substantially parallel to each other. That is, the two drive magnet pieces 13 and 14 arranged at diagonal positions inside the first case body 7 are arranged such that the slope portions 13b and 14b face each other.

  The driving magnet piece 13 is fixed to the bottom 7 a of the first case body 7. Specifically, the end surface on the subject side of the driving magnet piece 13 is fixed to the surface on the side opposite to the subject of the bottom portion 7a, and the end surface on the subject side of the driving magnet piece 13 is on the side opposite to the subject side of the bottom portion 7a. It is in contact with the surface. The bottom portion 7 a of the first case body 7 of the present embodiment is a subject-side magnetic member that abuts on the subject-side end surface of the driving magnet unit 11.

  A flat magnetic plate 15 made of a magnetic material is fixed to the end surface of the driving magnet piece 14 on the side opposite to the subject, and the magnetic plate 15 is attached to the end surface of the driving magnet piece 14 on the side opposite to the subject. It is in contact. The magnetic plate 15 is formed so that the shape when viewed from the optical axis direction is a substantially right-angled isosceles triangle, and as shown in FIG. 6, the oblique side portion and the slope portion 14 b of the driving magnet piece 14. Are fixed to the drive magnet piece 14 so as to be substantially parallel to each other. Further, the magnetic plate 15 is in contact with the inner peripheral surface of the cylindrical portion 7 b of the first case body 7. The magnetic plate 15 of this embodiment is an anti-subject-side magnetic member that contacts the end surface of the driving magnet unit 11 on the anti-subject side.

  As shown in FIG. 5, the drive coil 12 is wound so that the shape when viewed from the optical axis direction is a substantially right-angled isosceles triangle. As shown in FIG. 2, the four drive coils 12 are fixed to the outer peripheral surface of the small diameter portion 6 a of the sleeve 6. Specifically, the four driving coils 12 are arranged at a pitch of about 90 ° so that the inner circumferential surface of the driving coil 12 and the outer circumferential surface of the driving magnet portion 11 are substantially parallel with a predetermined gap. The driving coil 12 is fixed to the outer peripheral surface of the small-diameter portion 6 a, and is disposed at the four corners inside the first case body 7. The drive coil 12 is disposed at the four corners inside the first case body 7 with predetermined gaps between the drive coil 12 and the inner peripheral surface of the first case body 7, and together with the sleeve 6, the optical axis. It can move in the direction.

  In the present embodiment, when no current is supplied to the driving coil 12, as shown in FIG. 2, the driving magnet piece 13 facing the center position of the driving coil 12 in the optical axis direction in the optical axis direction, The driving magnet unit 11 and the driving coil 12 are arranged so that the center position between the 14 opposing surfaces substantially coincides. The width H (see FIG. 2) of the drive coil 12 in the optical axis direction is the distance D (see FIG. 2) between the opposing surfaces of the drive magnet pieces 13 and 14 facing in the optical axis direction, and the movable body. It is more than the sum of two movable distances. Therefore, in this embodiment, the opposite side end of the driving coil 12 does not move toward the subject side rather than the subject side end of the driving magnet piece 14 and the subject side end of the driving coil 12 is driven. The magnet piece 13 does not move to the side opposite the subject than the end on the side opposite the subject. In this embodiment, the four drive coils 12 are formed by winding one conductive wire in sequence.

  As shown in FIGS. 4 and 6, the two drive magnet pieces 13 and 14 constituting the drive magnet unit 11 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 13 and 14 are both magnetized to the same magnetic pole. Therefore, as shown in FIGS. 4 and 5, a magnetic flux F passing through the three surfaces of the drive coil 12 is generated between the drive magnet pieces 13 and 14. That is, the driving magnet unit 11 is magnetized so that a magnetic flux F passing through the driving coil 12 is generated at a position facing the driving coil 12.

  As shown in FIG. 6, 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 13 and 14 constituting the driving magnet unit 11. This is different from the magnetic poles formed on the opposing surfaces of the drive magnet pieces 13 and 14. That is, the magnetic pole formed at the intermediate position in the optical axis direction of the driving magnet unit 11 is formed at the intermediate position in the optical axis direction of another driving magnet unit 11 adjacent in the circumferential direction of the lens driving device 1. Is different.

  For example, the magnetic poles formed on the opposing surfaces of the driving magnet pieces 13 and 14 arranged on the right and left sides in FIG. 6 are S poles, and the driving magnet pieces 13 arranged on the upper and lower sides in FIG. , 14 are N poles. Therefore, in the example shown in FIG. 6, from between the driving magnet pieces 13 and 14 disposed on the upper and lower sides in FIG. 6 to between the driving magnet pieces 13 and 14 disposed on the right and left sides in FIG. A magnetic flux F heading is generated.

  In this embodiment, the magnetic poles formed on the opposing surfaces of the two driving magnet pieces 13 and 14 are formed on the opposing surfaces of the other two driving magnet pieces 13 and 14 adjacent in the circumferential direction. 6, the winding direction of the drive coil 12 disposed around the drive magnet pieces 13, 14 disposed on the upper side and the lower side of FIG. 6, and the right side and the left side of FIG. 6. The winding direction of the drive coil 12 disposed around the drive magnet pieces 13 and 14 is different.

(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 11 and substantially triangular cylindrical driving coils at the four corners. 12 is arranged. For this reason, the driving magnet unit 11 and the driving coil 12 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.

  Further, in this embodiment, the inner peripheral surface of the drive coil 12 wound in a substantially triangular cylindrical shape is disposed opposite to the outer peripheral surface of the drive magnet unit 11 with a predetermined gap, and the drive magnet unit 11 Is magnetized so that a magnetic flux F passing through the driving coil 12 is generated at a position facing the driving coil 12. Therefore, a magnetic circuit for driving the movable body 2 using the entire circumference of the drive magnet unit 11 and the entire circumference of the drive coil 12 can be efficiently formed. Therefore, a predetermined driving force for driving the movable body 2 can be obtained even if the driving magnet unit 11 and the driving coil 12 are downsized. That is, it is possible to reduce the size of the driving magnet unit 11 and the driving coil 12 while securing a driving force for driving the movable body 2.

  As described above, in this embodiment, the driving magnet unit 11 and the driving coil 12 can be reduced in size, and the driving magnet 11 and the driving coil 12 are arranged at the four corners of the lens driving device 1 that becomes a dead space. can do. Therefore, in this embodiment, even when the diameter of the mounted lens is increased, the lens driving device 1 can be reduced in size.

  In this embodiment, the opposing surfaces of the two drive magnet pieces 13 and 14 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 12 can be increased between the opposing surfaces of the two driving magnet pieces 13 and 14. Therefore, a magnetic circuit for driving the movable body 2 can be formed more efficiently, and the drive magnet unit 11 and the drive coil 12 can be further downsized.

  In this embodiment, a predetermined gap is formed between the driving magnet piece 13 and the driving magnet piece 14 in the optical axis direction. Therefore, even if the dimensional accuracy of the driving magnet pieces 13 and 14 in the optical axis direction is low, the dimensional error of the driving magnet pieces 13 and 14 in the optical axis direction can be absorbed by this gap. That is, it is possible to reduce the dimensional accuracy of the driving magnet pieces 13 and 14 and the like, and it is possible to reduce the manufacturing cost of parts such as the driving magnet pieces 13 and 14.

  In this embodiment, the four drive magnet portions 11 and the drive coil 12 are arranged on the inner peripheral side of the cylindrical portion 7b of the first case body 7 formed in a substantially square cylindrical shape. In this embodiment, the end surface on the subject side of the driving magnet piece 13 is in contact with the surface on the side opposite to the subject of the bottom portion 7 a, and the end surface on the side opposite to the subject of the driving magnet piece 14 is in contact with the magnetic plate 15. Yes. Therefore, leakage of the magnetic flux F generated by the driving magnet unit 11 can be suppressed, and an efficient magnetic circuit can be formed.

  In particular, in this embodiment, the magnetic poles formed on the opposing surfaces of the two drive magnet pieces 13 and 14 constituting the drive magnet unit 11 are the other two drives adjacent in the circumferential direction of the lens drive device 1. The magnetic poles are different from the magnetic poles formed on the facing surfaces of the magnet pieces 13 and 14, for example, between the driving magnet pieces 13 and 14 disposed on the upper side and the lower side in FIG. A magnetic flux F is generated between the drive magnet pieces 13 and 14 disposed. Therefore, even if a magnetic member (that is, a yoke) is not disposed inside the driving magnet portion 11 in the radial direction of the lens driving device 1, the driving magnet portions 11 adjacent to each other in the circumferential direction of the lens driving device 1 are arranged. An efficient magnetic circuit can be formed.

  In this embodiment, the width H of the drive coil 12 in the optical axis direction is equal to or greater than the sum of the distance D between the opposing surfaces of the drive magnet pieces 13 and 14 facing in the optical axis direction and the movable distance of the movable body 2. It has become. Therefore, the density of the magnetic flux F passing through the driving coil 12 can be made uniform at any position in the optical axis direction within the movable range of the movable body 2. Therefore, the driving force of the movable body 2 can be stabilized within the movable range of the movable body 2.

  In this embodiment, the driving coil 12 is fixed to the outer peripheral surface of the small diameter portion 6 a of the sleeve 6. Therefore, the driving magnet portion 11 can be disposed at a position closer to the sleeve 6 as compared with the case where the driving coil 12 is fixed to the outer peripheral surface of the large diameter portion 6b. Therefore, the lens driving device 1 can be further downsized.

  In this embodiment, the four driving coils 12 are formed by winding one conductive wire in sequence. Therefore, the number of power feeding terminals for supplying current to the four driving coils 12 can be minimized, and the configuration of the lens driving device 1 can be simplified.

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

  In the embodiment described above, a predetermined gap is formed between the facing surfaces of the drive magnet pieces 13 and 14. In addition, for example, the opposing surfaces of the drive magnet pieces 13 and 14 may be in contact with each other. Further, as shown in FIG. 7, a magnetic plate 21 made of a magnetic material may be disposed between the driving magnet piece 13 and the driving magnet piece 14 in the optical axis direction. According to the inventor's study, when the magnetic plate 21 is disposed between the drive magnet pieces 13 and 14, compared to the case where a gap is formed between the drive magnet pieces 13 and 14, The density of the magnetic flux F passing through the drive coil 12 can be effectively increased. In this case, for example, the facing surfaces of the drive magnet pieces 13 and 14 are in contact with the magnetic plate 21. Further, the magnetic plate 21 is formed in a flat plate shape whose shape when viewed from the optical axis direction is a substantially right-angled isosceles triangle.

  In the embodiment described above, the driving magnet unit 11 is constituted by the two driving magnet pieces 13 and 14. In addition to this, for example, as shown in FIG. 8, the drive magnet portion 11 may be configured by only one drive magnet piece 23. In this case, as shown in FIG. 8, the driving magnet piece 23 is 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. Yes. That is, the driving magnet piece 23 is magnetized so that a magnetic flux F passing through the driving coil 12 is generated at a position facing the driving coil 12. In this case, assembly of the lens driving device 1 is facilitated. In this case, the rigidity of the lens driving device 1 can be increased.

  In the embodiment described above, the driving magnet unit 11 and the driving coil 12 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 unit 11 and the driving coil 12 are arranged at three, two or only 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 unit 11 and the driving coil 12 are not arranged, and is engaged with the guide shaft. An engaging recess may be formed in the sleeve 6.

  In the embodiment described above, the four drive coils 12 are formed by winding one conductive wire in sequence. In addition, for example, the four drive coils 12 may be formed by winding four conductive wires. That is, one driving coil 12 may be formed by one conductive wire. In this case, it becomes possible to individually supply current to the four drive coils 12. Therefore, by controlling the direction and current value of the current supplied to the four drive coils 12, the inclination of the lens held by the movable body 2 with respect to the optical axis L can be corrected in all directions. . Further, when a camera shake detection sensor is mounted on the lens driving device 1 or the camera on which the lens driving device 1 is mounted, the output signals from the sensor are used to supply the four driving coils 12. By controlling the direction of current and the current value, it is possible to perform camera shake correction.

  In order to simplify the control circuit for supplying current to the drive coil 12 and the current supply control to the drive coil 12, the current is not supplied to the four drive coils 12 separately. A pair of the driving coils 12 may be paired, and current may be individually supplied to the two pairs of driving coils 12. In this case, the two driving coils 12 arranged symmetrically with respect to the optical axis L so that the two driving coils 12 arranged symmetrically with respect to the optical axis L are paired. The two driving coils 12 adjacent in the circumferential direction of the lens driving device 1 may be connected to each other, and the two driving coils 12 adjacent in the circumferential direction of the lens driving device 1 may be paired. May be connected.

  When two drive coils 12 arranged symmetrically with respect to the optical axis L are connected, the inclination of the lens with respect to the optical axis L can be corrected in two directions orthogonal to each other. As a result, the inclination of the lens with respect to the optical axis L can be corrected in all directions. Further, when two driving coils 12 adjacent in the circumferential direction of the lens driving device 1 are connected (for example, the driving coil 12 disposed on the left side in FIG. 3 and the driving coil 12 disposed on the lower side). And the drive coil 12 disposed on the right side of FIG. 3 and the drive coil 12 disposed on the upper side are connected), the inclination of the lens with respect to the optical axis L is corrected in one direction. be able to. In this case, in order to obtain more stable characteristics, in consideration of the posture of the lens driving device 1 when mounted on the camera, the direction in which the lens tilt correction is necessary and the correction direction of the lens tilt are matched. It is preferable to make it.

  In the embodiment described above, a plurality of lenses are fixed on the inner peripheral side of the lens holder 5 held by the sleeve 6. In addition, for example, a plurality of lenses may be directly fixed to the inner peripheral side of the sleeve 6. In the case of a lens driving device in which a driving coil is wound around the outer periphery of the sleeve as in the lens driving device described in Patent Document 1, the sleeve after the lens is fixed on the inner peripheral side is set in a winding machine. It is difficult to wind the drive coil around the sleeve. However, in this embodiment, the driving coil 12 wound in an air-core shape can be easily attached to the outer peripheral surface of the sleeve 6 after the lens is fixed to the inner peripheral side.

  In the embodiment described above, the width H of the driving coil 12 in the optical axis direction is the sum of the distance D between the opposing surfaces of the driving magnet pieces 13 and 14 facing in the optical axis direction and the movable distance of the movable body 2. That's it. In addition, for example, if the driving force of the movable body 2 can be obtained, the width H of the driving coil 12 is the distance between the facing surfaces of the driving magnet pieces 13 and 14 facing each other in the optical axis direction. It may be smaller than the sum of D and the movable distance of the movable body 2.

  In the embodiment described above, the magnetic poles formed on the opposing surfaces of the two drive magnet pieces 13 and 14 constituting the drive magnet unit 11 are the other two drives adjacent in the circumferential direction of the lens drive device 1. This is different from the magnetic poles formed on the opposing surfaces of the magnet pieces 13 and 14 for use. In addition, for example, the magnetic poles formed on the opposing surfaces of the two driving magnet pieces 13 and 14 are formed on the opposing surfaces of the other two driving magnet pieces 13 and 14 adjacent in the circumferential direction. It may be the same as the magnetic pole to be applied.

  In the embodiment described above, the sleeve 6 is formed in a substantially cylindrical shape with a step, but the sleeve 6 may be formed in a substantially cylindrical shape without a step. In the embodiment described above, the drive coil 12 is fixed to the movable body 2 side and the drive magnet section 11 is fixed to the fixed body 3 side. However, the drive magnet section 11 is fixed to the movable body 2 side. The driving coil 12 may be fixed to the fixed body 3 side.

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 principal part of the lens drive device shown in FIG. FIG. 4 is a side view of the drive magnet unit and the drive coil shown in FIG. 3. It is a figure which shows a drive magnet piece and a drive coil from the GG 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. It is a side view which shows the magnet part for a drive concerning other embodiment of this invention. It is a side view which shows the magnet part for a drive concerning other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens drive device 2 Movable body 4 Drive mechanism 6 Sleeve 6a Small diameter part 6b Large diameter part 7 1st case body (case body)
7a Bottom (Subject side magnetic member)
DESCRIPTION OF SYMBOLS 11 Drive magnet part 12 Drive coil 13, 14 Drive magnet piece 15 Magnetic board (anti-subject side magnetic member)
21 Magnetic plate D Distance between opposing surfaces F Magnetic flux H Width of driving coil L Optical axis Z1 Subject side Z2 Opposite subject side

Claims (12)

A lens driving device having a substantially square shape when viewed from the optical axis direction of the lens,
A movable body that holds the lens and is movable in the optical axis direction; and a drive mechanism for driving the movable body in the optical axis direction;
The driving mechanism is wound in a substantially triangular cylinder-shaped driving magnet portion disposed in at least one of the four corners of the lens driving device, and has a substantially triangular cylindrical shape, and an inner peripheral surface thereof is an outer periphery of the driving magnet portion. A driving coil disposed opposite to the surface via a predetermined gap,
The lens driving device, wherein the driving magnet portion is magnetized so that a magnetic flux passing through the driving coil is generated at a position facing the driving coil. The drive magnet portion includes two drive magnet pieces having a substantially triangular prism shape arranged so as to overlap in the optical axis direction,
2. The lens driving device according to claim 1, wherein opposing surfaces of the two driving magnet pieces in the optical axis direction are both magnetized to the same magnetic pole.   3. The lens driving device according to claim 2, wherein a gap is formed between the two driving magnet pieces in the optical axis direction.   The lens driving device according to claim 2, wherein the driving magnet unit includes a magnetic plate formed of a magnetic material and disposed between the two driving magnet pieces in the optical axis direction.   The width of the driving coil in the optical axis direction is equal to or greater than the sum of the distance between the facing surfaces facing each other in the optical axis direction and the movable distance of the movable body. The lens driving device according to 3 or 4. The driving magnet portion is disposed at four corners of the lens driving device,
A magnetic pole formed at an intermediate position in the optical axis direction of the driving magnet portion is formed at an intermediate position in the optical axis direction of another driving magnet portion adjacent in the circumferential direction of the lens driving device. The lens driving device according to claim 1, wherein the lens driving device is different from the lens driving device. The driving magnet portion is disposed at four corners of the lens driving device,
Magnetic poles formed on the facing surfaces of the two driving magnet pieces are magnetic poles formed on the facing surfaces of the other two driving magnet pieces adjacent in the circumferential direction of the lens driving device. 6. The lens driving device according to claim 2, wherein the lens driving device is different from the lens driving device.   The lens driving device according to any one of claims 1 to 7, further comprising a substantially square cylindrical case body formed of a magnetic material and disposed so as to surround the movable body and the driving mechanism.   A subject-side magnetic member formed of a magnetic material and in contact with an end surface on the subject side of the driving magnet portion; and an anti-subject side magnetic member formed of a magnetic material and in contact with an end surface on the anti-subject side of the driving magnet portion. The lens driving device according to claim 1, comprising: a lens driving device according to claim 1. The movable body includes a substantially cylindrical sleeve in which the lens is disposed on the inner peripheral side,
The sleeve includes a small-diameter portion disposed on the subject side and a large-diameter portion disposed on the anti-subject side and having a larger outer diameter than the small-diameter portion,
The lens driving device according to claim 1, wherein the driving coil is fixed to an outer peripheral surface of the small diameter portion. The driving magnet unit and the driving coil are arranged at four corners of the lens driving device,
11. The lens driving device according to claim 1, wherein the four driving coils are formed by sequentially winding one conductive wire. The driving magnet unit and the driving coil are arranged at four corners of the lens driving device,
11. The lens driving device according to claim 1, wherein the four driving coils are each formed by winding four conductive wires. 11.

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