JP2010014920A - Lens drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens drive device in which both the drive performance and impact resistance performance of a magnetic drive mechanism are increased. <P>SOLUTION: In the lens drive device 1, drive magnets 17 are arranged in the corners 184 and recesses 182b of the square cylinder 185. This causes the magnetic forces of the drive magnets 17 to efficiently act on a drive coil 30. The magnetic drive mechanism 5a consequently exhibits great thrust, so that the spring forces of the first and second spring members 14x and 14y can be improved. The first and second spring members 14x and 14y therefore can hold a movable body 3 comparatively firmly, thereby improving the impact resistance performance of the lens drive device 1 by the first and second spring members 14x and 14y. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lens driving device including a lens driving mechanism that magnetically drives a moving body including a lens in an optical axis direction.

  A camera mounted on a mobile phone with a camera, a digital camera, or the like includes a lens driving device including a support, a moving body including a lens, and a magnetic driving mechanism that magnetically drives the moving body in the lens optical axis direction. Have. In such a lens driving device, a spring member is disposed between the support and the moving body, and the spring member has a function of assisting the driving of the moving body.

  In such a lens drive device, the magnetic drive mechanism is held on the drive coil held on the outer peripheral surface of the movable body, the yoke having a square tube portion surrounding the movable body, and the inner peripheral surface of the yoke. A driving magnet (see Patent Documents 1, 2, and 3).

Among these patent documents, in the magnetic drive mechanism described in Patent Document 1, the drive magnet is disposed only at the corner portion of the rectangular tube portion of the yoke. Moreover, in the magnetic drive mechanism described in Patent Document 2, a concave portion recessed outward in the radial direction is provided on the side surface portion of the rectangular tube portion of the yoke, and the drive magnet is disposed only in the concave portion. Further, in the magnetic drive mechanism described in Patent Document 3, as shown in FIG. 5, the drive magnet 17 is disposed only in the corner portion 184 of the rectangular tube portion 185 of the yoke 18, and the side surface of the rectangular tube portion 185 of the yoke 18. A stopper projection that protrudes toward the inside of the recess 182b provided in the portion 182 is provided on the moving body 3, and when the moving body 3 is tilted, the moving body 3 is displaced in a direction intersecting the optical axis, or moved. When the body 3 rotates around the optical axis, the projection 13a is brought into contact with the inner wall of the recess 182b to improve the impact resistance of the lens device.
JP 2008-20668 A JP 2006-81387 A JP 2008-112128 A

  In addition to improving the driving performance of the magnetic driving mechanism so that the moving body can be driven quickly, the lens driving device is required to improve the impact resistance performance. However, as in Patent Documents 1 and 2, a configuration in which the drive magnet is disposed only at the corner of the rectangular tube portion of the yoke, or a configuration in which the drive magnet is disposed only in the recess provided in the side surface portion of the yoke. Then, it is difficult not only to improve the drive performance of the magnetic drive mechanism, but also to improve the shock resistance performance because there is no position to provide the stopper.

  On the other hand, in the configuration described in Patent Document 3, although the impact resistance performance is improved, it is difficult to improve the drive performance of the magnetic drive mechanism because the drive magnet is disposed only at the corner of the rectangular tube portion of the yoke. It is.

  In view of the above problems, an object of the present invention is to provide a lens driving device capable of enhancing both the driving performance and impact resistance performance of a magnetic driving mechanism.

  In order to solve the above problems, in the present invention, a support body, a moving body provided with a lens, a magnetic drive mechanism that magnetically drives the moving body in the lens optical axis direction, the support body, and the movement A spring member that is connected to a body and applies a biasing force to the movable body, wherein the magnetic drive mechanism includes a drive coil that is held on an outer peripheral surface of the movable body, and the movable body. A yoke having a rectangular tube portion surrounding the body, and a drive magnet held on the inner peripheral surface of the yoke, the concave portion recessed in the radially outer side at a side surface portion of the rectangular tube portion The drive magnet is arranged in a corner portion of the rectangular tube portion and in the concave portion.

  In the present invention, the yoke is formed with a concave portion that is recessed radially outward at the side surface portion of the rectangular tube portion, and the drive magnet is disposed in both the corner portion and the concave portion of the rectangular tube portion. Compared with the case where the drive magnet is disposed only in the corner portion of the tube portion or only in the recess, the magnetic drive mechanism can increase the drive performance of the magnetic drive mechanism, such as exerting a large thrust. In addition, a spring member that applies an urging force to the moving body is disposed between the support and the moving body. In the present invention, the spring force of the spring member is increased by the amount that the driving performance of the magnetic driving mechanism is increased. Can be increased. Therefore, since the moving body can be more strongly held by the spring member, the impact resistance can be improved by the spring member.

  In this invention, it is preferable that the said drive magnet is arrange | positioned at the perimeter which surrounds the circumference | surroundings of the said mobile body, or a substantially perimeter. If comprised in this way, since a magnetic drive mechanism exhibits the largest thrust, while improving drive performance, since the spring force of a spring member can be raised by that much, impact resistance performance can be improved. .

  In the present invention, the drive magnet is preferably made of a rare earth magnet. If comprised in this way, since a magnetic drive mechanism exhibits a bigger thrust, while improving drive performance, since the spring force of a spring member can be raised by that much, impact resistance performance can be improved. .

  In the present invention, the rare earth magnet is a sintered magnet, and the sintered magnet is a first magnet piece disposed at the corner portion of the rectangular tube portion, and the first magnet piece within the concave portion. It is preferable to arrange as a separate second magnet piece. While the sintered magnet is excellent in magnetic properties, it has a drawback that it is difficult to form a complicated shape. However, the sintered magnet is disposed at the corner portion of the rectangular tube portion. If one magnet piece and the second magnet piece separate from the first magnet piece are arranged in the recess, the shape thereof can be simplified. Therefore, a sintered magnet can be used as the rare earth magnet.

  In this invention, it is preferable that the said 1st magnet piece and the said 2nd magnet piece are arrange | positioned so that the edge parts of the circumferential direction may adjoin. If comprised in this way, since a magnetic drive mechanism exhibits a bigger thrust, while improving drive performance, since the spring force of a spring member can be raised by that much, impact resistance performance can be improved. .

  In the present invention, between the moving body and the support body, when the support body is tilted, when the support body is displaced in a direction intersecting the optical axis, or when the support body is around the optical axis. It is preferable that a stopper which contacts when rotating is configured. If comprised in this way, impact-resistant performance can be improved further. As such a stopper, for example, in the moving body, a protrusion protruding into the recess at a position shifted in the optical axis direction with respect to the drive magnet can be used. In the moving body, if a protrusion protruding into the recess is formed at a position displaced in the optical axis direction with respect to the drive magnet, a stopper that comes into contact when the moving body is displaced in a direction perpendicular to the optical axis direction or tilted. Therefore, in addition to improving the impact resistance performance by the spring force of the spring member, the impact resistance performance by the stopper can be improved. Further, since the protrusion constituting the stopper protrudes into the concave portion of the yoke at a position shifted in the optical axis direction with respect to the driving magnet in the movable body, there is no problem in disposing the driving magnet in the concave portion.

  In the present invention, the yoke is formed with a concave portion that is recessed radially outward at the side surface portion of the square tube portion, and the drive magnet is disposed both in the corner portion and in the concave portion of the square tube portion. Can increase the drive performance of the magnetic drive mechanism, such as exerting a large thrust. In addition, a spring member that applies an urging force to the moving body is disposed between the support and the moving body. In the present invention, the spring force of the spring member is increased by the amount that the driving performance of the magnetic driving mechanism is increased. Can be increased. Therefore, since the moving body can be more strongly held by the spring member, the impact resistance can be improved by the spring member.

  The best mode for carrying out the present invention will be described below with reference to the drawings. The lens driving device described below can be attached to various electronic devices in addition to the camera-equipped mobile phone. For example, it can be used for a thin digital camera, PHS, PDA, bar code reader, surveillance camera, camera for checking the back of a car, a door having an optical authentication function, and the like.

(Entire configuration of lens driving device)
1A and 1B are an external view and an exploded perspective view, respectively, of a lens driving device to which the present invention is applied as viewed obliquely from above.

  1A and 1B, a lens driving device 1 according to the present embodiment is a thin camera used for a camera-equipped mobile phone or the like. For example, three lenses 121 are placed along a subject (object side) along the optical axis direction. For moving in both directions, A direction (front side) approaching and B direction (rear side) approaching the opposite side (image side) to the subject, and has a substantially rectangular parallelepiped shape. The lens driving device 1 generally has a moving body 3 having a cylindrical lens holder 12 having one or more lenses 121 and a fixed diaphragm inside, and moves the moving body 3 along the optical axis direction. It has a lens driving mechanism 5 and a support 2 on which the lens driving mechanism 5 and the moving body 3 are mounted. The moving body 3 includes a cylindrical sleeve 13, and a cylindrical lens holder 12 is fixed to the inside thereof. Therefore, the outer shape of the moving body 3 is defined by the sleeve 13 and has a substantially cylindrical shape.

  The support 2 includes a rectangular holder 19 for holding an image sensor (not shown) on the image side, a box-shaped yoke 18 positioned on the subject side, and a spacer 11. In the center of 11, circular entrance windows 110 and 180 for taking light from the subject into the lens 121 are formed. The yoke 18 is made of a ferromagnetic plate such as a steel plate, and constitutes a linkage magnetic field generator 4 that generates a linkage magnetic field in the drive coil 30 held by the sleeve 13 together with the drive magnet 17 as will be described later. .

  The lens driving mechanism 5 includes a drive coil 30 wound around the outer peripheral surface of the sleeve 13 and a linkage magnetic field generator 4 that generates a linkage magnetic field in the drive coil 30. The drive coil 30 and the linkage magnetic field generator 4 constitutes a magnetic drive mechanism 5a.

  The interlinkage magnetic field generator 4 is provided with a drive magnet 17 at a position facing the drive coil 30 on the outer peripheral side, and the drive magnet 17 is fixed to the inner peripheral surface of the rectangular tube portion 185 of the yoke 18 with an adhesive. Has been.

  The yoke 18 has a box shape that covers the side surface and the upper surface side of the drive coil 30, reduces leakage magnetic flux from the magnetic path formed between the drive magnet 17 and the drive coil 30, and the sleeve. The linearity between the amount of movement of 13 and the current passed through the drive coil 30 is improved.

  The lens driving mechanism 5 further includes a first spring member 14x and a second spring connected to the support 2 and the movable body 3 between the holder 19 and the sleeve 13 and between the spacer 11 and the sleeve 13, respectively. A member 14y is provided. The first spring member 14 x is connected to the holder 19 and the sleeve 13, and the second spring member 14 y is connected to the spacer 11 and the sleeve 13. For this reason, a plurality of small protrusions 13y for connecting the second spring member 14y are formed in the circumferential direction on the upper end surface (end surface on the subject side) of the sleeve 13, and the lower end surface (on the image sensor side) of the sleeve 13 is formed. A plurality of small protrusions 13x for connecting the first spring member 14x are formed on the end surface in the circumferential direction.

  The first spring member 14x and the second spring member 14y make the movable body 3 supported by the support body 2 so as to be movable along the lens optical axis, and the movable body 3 has moved along the lens optical axis. At the same time, it exerts a biasing force. The first spring member 14x and the second spring member 14y are both made of metal such as beryllium copper or SUS steel, and are formed by pressing a thin plate having a predetermined thickness or etching using a photolithography technique. It is.

  Of the first spring member 14x and the second spring member 14y, the first spring member 14x disposed on the holder 19 side is divided into two spring pieces 14a and 14b. The start end and the winding end are each connected to the spring pieces 14a, 14b. At that time, of the two terminals of the drive coil 30, the object-side terminal passes under a groove (not shown) formed on the outer peripheral surface of the sleeve 13, and then dive under the drive coil 30 and spring pieces. It is routed to 14a. In the first spring member 14x, the spring pieces 14a and 14b are each formed with a terminal 14c, and the first spring member 14x (spring pieces 14a and 14b) also functions as a power supply member for the drive coil 30.

  In this embodiment, the lens driving mechanism 5 further includes a ring-shaped magnetic piece 130 held at the upper end of the sleeve 13, and the magnetic piece 130 has an attractive force acting between the driving magnet 17. Thus, an urging force in the optical axis direction is applied to the moving body 3. For this reason, since it is possible to prevent the moving body 3 from being displaced by its own weight when no power is supplied, it is possible to maintain the desired posture of the moving body 3 and to further improve the impact resistance performance. Further, the magnetic piece 130 acts as a kind of back yoke, and can reduce leakage magnetic flux from a magnetic path formed between the drive magnet 17 and the drive coil 30. In addition, as a magnetic piece, a rod-shaped magnetic body may be used.

  The spacer 11 is attached to the inner surface of the top plate portion 188 of the yoke 18 and has a plate portion 115 in which an incident window 110 is formed at the center. Small protrusions 112 are formed at the four corners of the plate portion 115 so as to protrude to the opposite side to the subject side.

  In addition, the holder 19 has small protrusions 192 extending toward the subject at the four corners. The small protrusion 192 of the holder 19 and the small protrusion 112 of the spacer 11 are used when the first spring member 14x and the second spring member 14y are connected to the support 2 respectively.

(Detailed configuration of yoke 18 and drive magnet 17)
2A and 2B are a plan view of a magnetic driving mechanism of a lens driving device to which the present invention is applied, and an explanatory diagram showing a positional relationship between a driving magnet and the like used in the magnetic driving mechanism.

  In this embodiment, as shown in FIGS. 1B and 2A, in the rectangular tube portion 185 of the yoke 18, the pair of opposing side surface portions 181 are formed in a flat shape, and the other pair of opposing side surfaces. The portion 182 is formed with a concave portion 182b that is recessed outward (radially outward as viewed from the moving body 3) compared to the both end portions 182a.

  In this embodiment, as shown in FIG. 1B and FIGS. 2A and 2B, the drive magnet 17 has a substantially triangular prism shape held by the corner portion 184 of the rectangular tube portion 185 of the yoke 18. The first magnet pieces 17a, 17b, 17c, and 17d and the flat plate-like second magnet pieces 17s and 17t held inside the recess 182b of the yoke 18 are used, and the first magnet piece 17a having a substantially triangular prism shape is used. , 17b, 17c, and 17d, both end portions extend along the side surface portions 181 and 182 of the yoke 18. For this reason, both end portions of the second magnet pieces 17 s and 17 t are close to the end portions of the first magnet pieces 17 a, 17 b, 17 c and 17 d, and the drive magnet 17 is arranged over substantially the entire circumference around the moving body 3. Is in a state of being A gap exists between the corner 184 of the yoke 18 and the first magnet pieces 17a, 17b, 17c, and 17d, and the gap functions as an adhesive reservoir.

  Each of the drive magnets 17 is divided into two in the optical axis direction, and in both cases, the inner surface and the outer surface are magnetized to different poles. In the four drive magnets 17, for example, the inner surface is magnetized to the N pole in the upper half, the outer surface is magnetized to the S pole, and the inner surface is magnetized to the S pole in the lower half. Magnetized. Therefore, the drive coil 30 is divided into two corresponding to the upper half and the lower half of the drive magnet 17, and the winding directions of the two divided drive coils are opposite.

  As such a drive magnet 17, a ferrite magnet or a rare earth magnet can be used. In this embodiment, rare earth magnets such as neodymium magnets are used for all of the first magnet pieces 17a, 17b, 17c and 17d and the second magnet pieces 17s and 17t. As such a rare earth magnet, a bond magnet and a sintered magnet can be used. In this embodiment, a sintered magnet is used.

(Basic operation)
FIG. 3 is an explanatory diagram schematically showing the operation of the lens driving device 1 shown in FIG. The left half of FIG. 3 shows a view when the sleeve 13 is at an infinite position (normal photographing position), and the right half of FIG. 3 is that the sleeve 13 is at a macro position (close-up photographing position). Figure shows when.

  As shown in FIG. 3, in the lens driving device 1 of the present embodiment, the moving body 3 is normally located on the imaging element side (image side), and in such a state, a current in a predetermined direction flows in the driving coil 30. , Each of the drive coils 30 receives an upward (front) electromagnetic force. Thereby, the sleeve 13 to which the drive coil 30 is fixed starts to move toward the subject side (front side). At this time, elastic forces that restrict the movement of the sleeve 13 are generated between the second spring member 14y and the front end of the sleeve 13 and between the first spring member 14x and the rear end of the sleeve 13, respectively. For this reason, when the electromagnetic force that attempts to move the sleeve 13 to the front side and the elastic force that restricts the movement of the sleeve 13 are balanced, the sleeve 13 stops. At that time, the sleeve 13 (moving body 3) is brought to a desired position by adjusting the amount of current flowing through the drive coil 30 according to the elastic force acting on the sleeve 13 by the first spring member 14x and the second spring member 14y. Can be stopped.

  In this embodiment, since the first spring member 14x and the second spring member 14y are plate springs (gimbal springs) in which a linear relationship is established between the elastic force (stress) and the displacement amount (distortion amount), Linearity between the amount of movement of the sleeve 13 and the current passed through the drive coil 30 can be improved. In addition, since two spring members including the first spring member 14x and the second spring member 14y are used, a large balance force is applied in the direction of the optical axis X when the sleeve 13 is stopped. Even if other force such as centrifugal force or impact force acts in the direction of the axis X, the sleeve 13 can be stopped more stably. Further, in the lens driving device 1, the sleeve 13 is not stopped by colliding with a collision material (buffer material) or the like, but is stopped using a balance between electromagnetic force and elastic force. Therefore, it is possible to prevent the occurrence of a collision sound.

(Main effects of this form)
As described above, in the lens driving device 1 of the present embodiment, in the rectangular tube portion 185 of the yoke 18, the pair of opposing side surface portions 182 are recessed toward the outside in the radial direction as compared with the both end portions 182a. 182b is formed, and the drive magnet 17 is disposed in both the corner portion 184 and the recess portion 182b of the rectangular tube portion 185. Therefore, compared with the case where the drive magnet 17 is disposed only in the corner portion 184 of the rectangular tube portion 185 of the yoke 18 or only in the recess 182b, the magnetic force of the drive magnet 17 is efficiently applied to the drive coil 30. Since the magnetic drive mechanism 5a can act, the drive performance of the magnetic drive mechanism 5a can be enhanced, such as exerting a large thrust.

  Further, a first spring member 14x and a second spring member 14y that apply a biasing force to the moving body 3 are arranged between the support body 2 and the moving body 3. In this embodiment, the driving of the magnetic drive mechanism 5a is performed. Since the performance is improved, the spring force of the first spring member 14x and the second spring member 14y can be increased. That is, when driving the moving body 3, the magnetic drive mechanism 5 a needs to exert a force against the spring force of the first spring member 14 x and the second spring member 14 y, but in this embodiment, the magnetic drive mechanism 5 a Since a large thrust can be generated, the spring force of the first spring member 14x and the second spring member 14y can be increased. Therefore, since the moving body 3 can be held more strongly by the first spring member 14x and the second spring member 14y, the impact resistance performance of the lens driving device 1 can be improved by the first spring member 14x and the second spring member 14y. Can be increased.

  Further, as the drive magnet 17, the substantially triangular prism-shaped first magnet pieces 17 a, 17 b, 17 c, and 17 d held by the corner portion 184 of the rectangular tube portion 185 of the yoke 18, and the concave portion 182 b of the yoke 18 are held. Flat second magnet pieces 17 s and 17 t are used, and substantially triangular prism-shaped first magnet pieces 17 a, 17 b, 17 c, and 17 d and a drive magnet 17 are divided and arranged at the four corners. Yes. For this reason, even when the gap between the yoke 18 and the sleeve 13 is narrow, it is possible to prevent a thin portion from being generated in the drive magnet 17 and increase the strength of the drive magnet 17. Further, since the four corner spaces between the moving body 3 and the yoke 18 are effectively used as the arrangement space for the drive magnet 17, the entire lens drive device 1 can be reduced in size.

  Moreover, since both ends of the substantially triangular prism-shaped first magnet pieces 17a, 17b, 17c, and 17d extend along the side surfaces 181 and 182 of the yoke 18, both ends of the second magnet pieces 17s and 17t are The drive magnet 17 is in a state where it is close to the end portions of the first magnet pieces 17 a, 17 b, 17 c, and 17 d and is disposed over substantially the entire circumference around the movable body 3. Further, the inner surfaces of the first magnet pieces 17a, 17b, 17c, and 17d have an arc shape corresponding to the outer peripheral surface of the moving body 3, and the space in which the first magnet pieces 17a, 17b, 17c, and 17d are arranged is narrow. The volume of the first magnet pieces 17a, 17b, 17c, and 17d is large. In addition, rare earth magnets are used for the drive magnets 17 (first magnet pieces 17a, 17b, 17c, 17d, and second magnet pieces 17s, 17t). Therefore, since the magnetic drive mechanism 5a exhibits a large thrust, the spring force of the first spring member 14x and the second spring member 14y can be increased accordingly. Therefore, since the moving body 3 can be held more strongly by the first spring member 14x and the second spring member 14y, the impact resistance performance of the lens driving device 1 can be improved by the first spring member 14x and the second spring member 14y. Can be increased.

  In the present embodiment, sintered magnets are used for the drive magnets 17 (first magnet pieces 17a, 17b, 17c, 17d, and second magnet pieces 17s, 17t), which have a high coercive force and self-demagnetization. Although it is excellent in magnetic characteristics such as being hardly affected by the action, it has a drawback that it is difficult to sinter into a complicated shape or to cut, but in this embodiment, the drive magnet 17 is a yoke. A substantially triangular prism-shaped first magnet piece 17a, 17b, 17c, 17d held by the corner portion 184 of the 18 square tube portion 185, and a flat plate-like second magnet piece 17s held inside the recess 182b of the yoke 18. , 17t, the shape is simple and a sintered magnet can be used.

  Further, in the lens driving device 1 having the complicated outer shape as in the present example, if the first magnet pieces 17a to 17d are cut into a continuous ring shape with a sintered magnet, the moving body 3 and the yoke Although it is necessary to thinly process the portion sandwiched between the 18 side portions, such processing is extremely difficult, and even when processed, there is a problem that the thin portion is easily damaged. However, in this embodiment, the magnets 17a to 17d arranged at the corners 184 of the yoke 18 as the first magnet pieces and the magnets 17s and 17t arranged inside the yoke 18 as the second magnet pieces are each substantially triangular prism-shaped. And cut into a flat plate shape. Therefore, processing for forming a thin portion is unnecessary and the problem of breakage in the thin portion does not occur. Moreover, if it is substantially triangular prism shape or flat plate shape, the cutting residue of magnet material can be reduced compared with ring shape, and magnet material can be utilized effectively. Therefore, according to this embodiment, it is possible to increase the thrust while improving the cutting efficiency from the magnet material.

[Other embodiments]
FIG. 4 is an explanatory diagram of a stopper configured in a lens driving device to which the present invention is applied. In the above embodiment, the impact resistance of the lens driving device 1 is increased by increasing the spring force of the first spring member 14x and the second spring member 14y by the amount that the magnetic drive mechanism 5a generates a large thrust. However, in addition to the above configuration, when the support 2 is inclined between the moving body 3 and the support 2, the support 2 is displaced in a direction intersecting the optical axis, or the support 2 is The impact resistance performance of the lens driving device 1 may be further improved by providing a stopper that comes into contact with each other when rotating around the optical axis.

  As such a stopper, for example, as shown in FIG. 4, in the moving body 3, the second magnet pieces 17s and 17t described with reference to FIGS. 1B, 2A, and 2B are used. The protrusions 13a and 13b protruding into the recess 182b of the yoke 18 can be used at positions shifted in the optical axis direction. According to such a configuration, when the support 2 is inclined, when the support 2 is displaced in a direction intersecting the optical axis, or when the support 2 is rotated around the optical axis, the protrusions 13a and 13b are formed in the recesses 182b. Functions as a stopper that contacts the inner surface.

  According to such a configuration, since the projections 13a and 13b are provided at positions shifted in the optical axis direction with respect to the second magnet pieces 17s and 17t, they interfere with the second magnet pieces 17s and 17t arranged in the recess 182b. do not do. Depending on the relationship between the amount of movement of the moving body 3 in the optical axis direction and the dimensions of the second magnet pieces 17s and 17t in the optical axis direction, the dimensions of the second magnet pieces 17s and 17t in the optical axis direction You may make it shorter than the dimension of the optical axis direction of 1 magnet piece 17a-17d.

  In the above embodiment, there is a gap between the first magnet pieces 17a to 17d and the second magnet pieces 17s and 17t. However, these magnet pieces may be arranged without a gap. The magnet 17 is configured to be disposed on the entire circumference surrounding the moving body 3.

  In the above-described embodiment, the first magnet pieces 17a to 17d and the second magnet pieces 17s and 17t are used as the drive magnet 17. However, a magnet that is integrally formed as a whole may be used. The magnet 17 is configured to be disposed on the entire circumference surrounding the moving body 3.

  In the above embodiment, gimbal springs having the same structure are used as the first spring member 14x and the second spring member 14y. However, the first spring member 14x and the second spring member 14y are optimized while optimizing the configuration of each of the first spring member 14x and the second spring member 14y. The spring force of 14x and the second spring member 14y may be increased, and the impact resistance performance of the lens driving device 1 may be increased. For example, this type of gimbal spring has a configuration in which a plurality of arm portions extend between an outer peripheral side connecting portion connected to the support body 2 and an inner peripheral side connecting portion connected to the moving body 3. However, for one of the first spring member 14x and the second spring member 14y, a first type spring member in which the arm portion extends in an arc shape in the circumferential direction is used, and for the other, a plurality of arm portions are provided. You may use the 2nd type spring member extended in the circumferential direction, meandering in a part. Of these two types of spring members, the first type spring member has an advantage that it can support the moving body 3 so that the optical axis does not deviate because the lateral spring constant is large. The spring member has a feature that the longitudinal spring constant is constant over a wide deformation range in the lens optical axis direction even if the arm portion is arranged in a narrow range in the circumferential direction because the arm portion meanders. ing. Therefore, the first type spring member having a large lateral spring constant is used as the second spring member 14y close to the position of the center of gravity of the moving body 3 out of the first spring member 14x and the second spring member 14y. About a spring member, if it uses as the 1st spring member 14x, the impact resistance performance of the lens drive device 1 can be improved to the extent that the movement of the horizontal direction of the mobile body 3 can be controlled.

(A), (b) is the external view which looked at the lens drive device to which this invention is applied from diagonally upward, and an exploded perspective view, respectively. (A), (b) is a top view of the magnetic drive mechanism of the lens drive device to which this invention is applied, and explanatory drawing which shows positional relationships, such as a drive magnet used for the magnetic drive mechanism. It is explanatory drawing which shows typically operation | movement of the lens drive device shown in FIG. It is explanatory drawing of the stopper comprised in the lens drive device to which this invention is applied. It is a top view of the magnetic drive mechanism of the conventional lens drive device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens drive device 2 Support body 3 Moving body 11 Spacer 13 Sleeve 14x 1st spring member 14y 2nd spring member 17 Drive magnet 17a, 17b, 17c, 17d 1st magnet piece 17s, 17t 2nd magnet piece 18 Yoke 19 Holder 30 Drive coil 182b Yoke recess 184 Yoke corner 185 Yoke square tube

Claims (6)

A support, a moving body including a lens, a magnetic drive mechanism that magnetically drives the moving body in the lens optical axis direction, and a biasing force applied to the moving body that is connected between the support and the moving body. A lens driving device having a spring member to be applied,
The magnetic drive mechanism includes a drive coil held on the outer peripheral surface of the movable body, a yoke having a rectangular tube portion surrounding the movable body, a drive magnet held on the inner peripheral surface of the yoke, With
The yoke includes a concave portion that is recessed radially outward at a side surface portion of the rectangular tube portion,
The lens driving device according to claim 1, wherein the driving magnet is disposed in a corner portion of the rectangular tube portion and in the concave portion.   The lens driving device according to claim 1, wherein the driving magnet is arranged on an entire circumference or substantially an entire circumference surrounding the movable body.   The lens driving device according to claim 1, wherein the driving magnet is made of a rare earth magnet. The rare earth magnet is a sintered magnet,
The sintered magnet is disposed in a first magnet piece disposed in the corner portion of the rectangular tube portion and in the concave portion, and is disposed as a second magnet piece separate from the first magnet piece. The lens driving device according to claim 3.   The lens driving device according to claim 4, wherein the first magnet piece and the second magnet piece are arranged so that end portions in a circumferential direction are close to each other.   Between the moving body and the support body, when the moving body is tilted, when the moving body is displaced in a direction intersecting the optical axis, or when the moving body rotates around the optical axis, The lens driving device according to any one of claims 1 to 5, wherein a stopper that contacts is configured.

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