JP4598563B2 - Lens drive device - Google Patents

Description

  The present invention relates to a lens driving device used for a digital camera or the like.

  A lens driving device mounted on a portable device such as a digital camera or a camera-equipped mobile phone includes a moving lens body provided with a lens, and a magnetic driving mechanism for moving the moving lens body linearly along the optical axis of the lens. A lens driving device provided has been proposed (see, for example, Patent Document 1).

Further, a lens driving device has been devised in which the rotor is rotationally driven by a stator, the rotational operation is converted into a linear motion, and the moving lens body is linearly magnetically driven along the optical axis of the lens.
JP-A-10-150759

  In any of these types of lens driving devices, in order to configure a magnetic driving circuit, one of a magnet and a coil is mounted on the moving lens body side, and the other is mounted on a fixed body side such as a case. For example, as shown in FIG. 4, in the moving lens body 10A, a sleeve 15A is fixed to the outer peripheral side of the lens holder 14A, and an annular magnet 31A is mounted using a flange portion 150A protruding on the outer peripheral side of the sleeve 15A. In this case, generally, after the magnet 31A is fitted into the sleeve 15A, an adhesive is injected into the gap between the inner peripheral surface of the magnet 31A and the outer peripheral surface of the sleeve 15A, and then the adhesive is cured, A method of fixing the sleeve 15A is employed.

  However, in such a method, the fixing strength between the magnet 31A and the sleeve 15A is not sufficient, and there is a problem that the magnet 31A comes off when an impact test is performed. Further, since it is necessary to secure a gap for injecting the adhesive between the inner peripheral surface of the magnet 31A and the outer peripheral surface of the sleeve 15A, there is a problem that the magnet 31A is fixed in an inclined posture. is there. Further, there is a problem that the position of the magnet 31A is shifted due to the shrinkage force when the adhesive is cured, or the magnet 31A is lifted from the flange portion 150A.

  In view of the above problems, an object of the present invention is to fix a magnetic means such as a magnet to a moving lens body with sufficient strength, and to securely fix the magnetic means in a predetermined posture and a predetermined position. An object of the present invention is to provide a lens driving device that can handle the above-described problem.

In order to solve the above problems, in the present invention, in a lens driving device having a moving lens body movable in the optical axis direction on a fixed body, and a magnetic driving mechanism for moving the lens moving body along the optical axis. The magnetic drive mechanism includes an annular magnet having a constant thickness fixed to the outer peripheral surface of the moving lens body, and a coil disposed on the fixed body side, and between the moving lens body and the magnet. Includes an engaging mechanism that mechanically connects the moving lens body and the magnet. The engaging mechanism includes a protrusion protruding in a radial direction from an inner peripheral surface of the magnet, and the moving lens. A protrusion holding portion that extends in the circumferential direction on the outer peripheral surface of the body and holds the protrusion from both sides in the optical axis direction when the protrusion is rotated around the optical axis;
The protrusion is characterized in that the thickness in the optical axis direction is the same as the thickness of the magnet.

In the present invention, between the annular magnet of the moving lens body with a predetermined thickness, since the engagement mechanism for mechanically connecting the moving lens body and the magnet are configured, the moving lens body and the magnet Can be fixed with sufficient strength. Therefore, when the impact test is performed, it is possible to reliably prevent the magnet from being detached from the moving lens body. Further, according to the present invention, when fixing the magnet to the moving lens body, it is not necessary to use any adhesive, or even if the adhesive is used, it is only used as an auxiliary. The magnet does not tilt on the moving lens body due to the influence of the contraction force when the agent is cured, and the magnet does not shift in position on the moving lens body. Furthermore, according to the present invention, when the magnet is manufactured, it is only necessary to form the protrusions at the same time, so that it is not necessary to change the structure of the magnetic means significantly. In addition, according to the present invention, after the movable lens body is inserted into the inside of the annular magnet, the protrusions are clamped from both sides in the optical axis direction by the protrusion clamping portion only by rotating these members relatively around the optical axis. Is done.

In the present invention, it is preferable that the engagement mechanism includes the protrusion and the protrusion holding portion at a plurality of locations in the circumferential direction. In such a configuration, the magnet engages with the moving lens body at a plurality of locations in the circumferential direction, so that the fixing strength between the magnet and the moving lens body can be further increased. Further, if the magnet is engaged with and held at a plurality of locations in the circumferential direction with respect to the moving lens body, it is possible to more reliably prevent the magnet from being displaced or inclined.

In the present invention, the engagement mechanism includes a projection guide portion on the other surface side that guides the projection to the entrance of the projection clamping portion when the movable lens body is inserted inside the magnet . Is preferred. With this configuration, after the movable lens body is inserted inside the magnet , the protrusions are sandwiched from both sides in the optical axis direction by the protrusion sandwiching portions simply by rotating these members relatively around the optical axis. Will be.

In the present invention, it is preferable that one side of a portion facing the both sides in the optical axis direction in the protrusion holding portion is a support surface that is formed over the entire circumferential direction and supports the entire inner peripheral edge of the magnet . If comprised in this way, a magnet can be reliably fixed to the attitude | position orthogonal to an optical axis.

In the present invention, the other side of the part that faces the both sides in the optical axis direction of the projection holding part extends obliquely in the circumferential direction, and the width dimension of the projection holding part in the optical axis direction is wide at the entrance side and narrow at the back side. It is preferable that it is the taper surface which carries out. If comprised in this way, it will be clamped strongly, so that a protrusion goes to the back of a protrusion clamping part. In addition, since the protrusion is pressed against the support surface as it goes deeper into the protrusion holding portion, the magnet can be reliably fixed in a posture orthogonal to the optical axis.

In the lens driving device according to the present invention, between the moving lens body and the annular magnet, the engagement mechanism for mechanically coupling the moving lens body and the magnet are configured, the moving lens body and the magnet Can be fixed with sufficient strength. Therefore, when the impact test is performed, it is possible to reliably prevent the magnet from being detached from the moving lens body. Further, according to the present invention, when fixing the magnet to the moving lens body, it is not necessary to use any adhesive, or even if the adhesive is used, it is only used as an auxiliary. The magnet does not tilt on the moving lens body due to the influence of the contraction force when the agent is cured, and the magnet does not shift in position on the moving lens body. Therefore, the yield and reliability of the lens driving device can be improved.

  A lens driving device to which the present invention is applied will be described below with reference to the drawings.

(overall structure)
1A and 1B are a plan view and a longitudinal sectional view of a lens driving device to which the present invention is applied. In FIG. 1B, the right side shows a state where the moving lens body has moved to the subject side (closest position side), and the left side shows the moving lens body on the image sensor side (infinity position side). The moved state is shown.

  1 (a) and 1 (b), the lens driving device 1 according to the present embodiment includes a digital camera or the like on which an imaging element (not shown) is disposed (one side in the optical axis L direction / infinite position side). And the subject side (the other side in the optical axis L direction / closest distance position side) and the lens system is reciprocated, and the three lenses 11, 12, 13 and the diaphragms 16, 17 are cylindrical. The moving lens body 10 provided in the lens holder 14, the magnetic driving mechanism 30 for driving the moving lens body 10 in the direction of the optical axis L, and the fixed body 20 containing the magnetic driving mechanism 30 and the moving lens body 10. And. The fixed body 20 includes a base member 21 to which an imaging element or the like is fixed, and a cover member 22 located on the subject side. The base member 21 and the cover member 22 have an outer diameter dimension of the moving lens body. Substantially equal openings are formed. In the moving lens body 10 of this embodiment, a cylindrical sleeve 15 is fixed to the outer peripheral side of the lens holder 14 by a screw mechanism or the like.

In this embodiment, the magnetic drive mechanism 30 includes an annular magnet 31 attached to the outer peripheral side of the moving lens body 10 via a sleeve 15, and an annular magnet disposed on one side in the optical axis L direction with respect to the magnet 31. The first stator coil 33 , the annular first yoke 34 disposed on the opposite side to the magnet 31 with respect to the first stator coil 33, and the other side in the optical axis L direction with respect to the magnet 31 An annular second stator coil 35 and an annular second yoke 36 disposed on the opposite side of the magnet with respect to the second stator coil 25 are provided. Here, the magnet 31 is magnetized to different poles on the inner peripheral side and the outer peripheral side. Note that, a part of the first yoke 34 is used, two power supply terminals (not shown) for winding the coil terminal of the first stator coil 33, and a part of the second yoke 36 are used. Thus, two power supply terminals 361 and 362 for winding the coil terminal of the second stator coil 35 are formed.

  In the lens driving device 1 configured in this manner, the energizing condition to the stator coils 33 and 35 of the magnetic driving mechanism 30 is controlled at the time of autofocusing, so that the moving lens body 10 is moved to one side and the other side in the optical axis L direction. The movable lens body 10 is held at these positions. That is, the state shown on the right side of FIG. 1B is a state in which the moving lens body 10 has moved to the closest distance position on the subject side, and such a state is between the magnet 31 and the second yoke 36. It is held by the acting magnetic attractive force. When a predetermined current is passed through the stator coils 33 and 35 from this state, a thrust toward the image pickup device acts on the moving lens body 10, and the moving lens body 10 picks up an image as shown on the left side of FIG. Move to the infinity position on the element side. Such a state is maintained by a magnetic attractive force acting between the magnet 31 and the first yoke 34. Further, when a predetermined current is passed through the stator coils 33 and 35 from the state shown on the left side of FIG. 1B, thrust toward the subject side acts on the moving lens body 10 and is shown on the right side of FIG. As described above, the moving lens body 10 moves to the closest distance position on the subject side. Such a state is maintained by a magnetic attractive force acting between the magnet 31 and the second yoke 36.

(Magnet 31 fixing structure and engagement mechanism configuration)
2A and 2B are a perspective view and a disassembled perspective view showing a state in which the magnet 31 is fixed to the outer peripheral surface of the sleeve 15 of the moving lens body 10 in the lens driving device 1 of the present embodiment. 3A and 3B are a plan view of the sleeve shown in FIG. 2 and a plan view of the magnet shown in FIG.

  In the lens driving device 1 of the present embodiment, in order to fix the magnet 31 to the outer peripheral surface of the moving lens body 10, in this embodiment, an engagement mechanism 40 described with reference to FIGS. 2 and 3 is configured.

  2 (a), 2 (b), and 3 (b), the magnet 31 used in the lens driving device 1 of the present embodiment is an iron-based magnet having a constant thickness and is radially inward from the inner peripheral surface thereof. Three protrusions 310 protrude toward the end. Here, the protrusions 310 are formed at equiangular intervals on the inner peripheral surface of the magnet 31.

  On the other hand, the sleeve 15 shown in FIGS. 2A, 2B, and 3A is a cylindrical resin molded product, and its outer peripheral surface has a substantially intermediate position in the optical axis direction. A flange portion 150 (one side of a portion facing the both sides in the optical axis direction in the protrusion holding portion) is formed to project outward in the radial direction. Further, L-shaped step portions 151 are formed at three locations on the outer peripheral surface of the sleeve 15 when viewed from the outer peripheral side surface. Here, the step portions 151 are formed on the outer peripheral surface of the sleeve 15 at equal angular intervals. In any of these three steps 151, the lateral portion 152 extending in the circumferential direction extends substantially parallel to the flange portion 150, and the longitudinal portion 153 extending in the optical axis direction is the clockwise CW of the lateral portion 152. Extends from the end located on the direction side to the position reaching the flange 150.

Here, the inner wall surface 153 of the lateral portion 152 of the stepped portion 151 (the other side of the portion that faces the projection pinching portion on both sides in the optical axis direction) extends obliquely from the entrance side toward the back side in the circumferential direction. Tapered surface. For this reason, when the width dimension W11 on the inlet side and the width dimension W12 on the back side are compared between the lateral portion 152 of the step portion 151 and the flange portion 150, the following relationship is established: Width W11
The rear side width dimension W12 is narrower than the inlet side width dimension W12.

In the sleeve 15 and the magnet 31 configured as described above, the height dimension (protrusion dimension to the outer peripheral side) h11 (protrusion dimension to the outer peripheral side) of the sleeve 15 and the height dimension h12 (protrusion dimension to the outer peripheral side). And the following relationship: Height dimension h11 of stepped part 151 <height dimension h12 of flange part 150
Therefore, the dimension d10 (radius of the outer peripheral surface of the sleeve 15) from the center of the sleeve 15 where the step portion 151 and the flange portion 150 are not formed, and the outer peripheral surface of the step portion 151 of the sleeve 15 are set. When the dimension d11 from the center and the dimension d12 from the center of the outer peripheral surface of the flange portion 150 are compared, the following relationship is established: the dimension d10 of the sleeve 15 <the dimension d11 of the step portion 151 <the dimension d12 of the flange portion 150.
Is set to

Further, in the magnet 31, the dimension d21 from the center of the inner peripheral surface of the protrusion 310 and the dimension d22 from the center of the portion where the protrusion 310 is not formed are related to the dimensions of the sleeve 15 and the relationship shown below. Dimension d10 <dimension d21 of protrusion 310 <dimension d11 of step 151
The dimension d11 of the step 151 <the dimension d22 of the part where the protrusion 310 is not formed.
The dimension d22 of the portion where the protrusion 310 is not formed <the dimension d12 of the flange portion 150
Is set to

Furthermore, the relationship between the thickness t21 of the magnet 31 and the width dimensions W11 and W12 of the flange portion 150 and the lateral portion 152 of the step portion 151 in the sleeve 15 is as follows. Dimension W12 <Inlet side width W11
Is set to

In addition, the distance L11 between the adjacent step portions 151 in the sleeve 15 and the circumferential length L21 of the projection 310 of the magnet 31 are as follows. The circumferential length L21 of the projection 310 <step 151 Distance L11 between
The interval L11 between the step portions 151 is wider than the circumferential length L21 of the protrusion 310.

Further, the circumferential dimension L12 of the lateral portion 152 of the step portion 151 of the sleeve 15 and the circumferential length L21 of the projection 310 of the magnet 31 are as follows. The circumferential dimension L12 of the lateral portion 152 < The circumferential length L21 of the protrusion 310
The circumferential dimension L12 of the lateral portion 152 of the step portion 151 is shorter than the circumferential length L21 of the protrusion 310 of the magnet 31.

  Therefore, in this embodiment, as described below for the engagement operation, when the projection 310 is rotated around the optical axis (clockwise CW direction) between the flange portion 150 and the step portion 151 in the sleeve 15. The projection 310 functions as a projection clamping unit 41 that clamps the projection 310 from both sides in the optical axis direction. Further, a portion corresponding to a portion between the adjacent step portions 151 in the sleeve 15 functions as a protrusion guide portion 42 that guides the protrusion 310 to the entrance of the protrusion holding portion 41 when the sleeve 15 is inserted inside the magnet 31. . Further, the flange portion 150 is formed over the entire circumferential direction and functions as a support surface that supports the inner peripheral edge of the magnet 31 over the entire circumferential direction and supports the magnet 31 in a posture orthogonal to the optical axis L.

  In the manufacturing process of the lens driving device 1 configured as described above, in the process of fixing the magnet 31 to the outer peripheral surface of the sleeve 15 of the moving lens body 10, first, the subject side end of the sleeve 15 is inserted inside the magnet 31. Thereafter, the magnet 31 is rotated clockwise CW to align the protrusion 310 of the magnet 31 and the adjacent step portions 151 in the sleeve 15. Next, when the sleeve 15 is further inserted inside the magnet 31, the projection 310 of the magnet 31 passes between adjacent step portions 151 in the sleeve 15 and hits the flange portion 150. In this state, the projection 310 is It is located at the entrance of the protrusion clamping part 41. Next, when the magnet 31 is further rotated in the clockwise direction CW, the projection 310 of the magnet 31 enters between the projection sandwiching portions 41, and the projection 310 of the magnet 31 engages with the projection sandwiching portion 41. The protrusion 310 is sandwiched between the flange portion 150 and the lateral portion 152 of the step portion 151 from both sides in the optical axis direction.

  Therefore, the magnet 31 is fixed to the outer peripheral surface of the sleeve 15 without being fixed with an adhesive. In this state, since the magnet 15 is supported by the flange portion 150 over the entire circumference, the magnet 31 is held in a posture orthogonal to the optical axis L. Since the circumferential dimension L12 of the lateral portion 152 of the step portion 151 of the sleeve 15 is shorter than the circumferential length L21 of the projection 310 of the magnet 31, the CCW direction of the projection 310 of the magnet 31 is counterclockwise. The end portion located at is slightly protruded from the protrusion holding portion 41.

(Main effects of this form)
As described above, in the lens driving device 1 of the present embodiment, the engagement mechanism 40 including the protrusion 310 and the protrusion clamping portion 41 is configured between the sleeve 15 of the moving lens body 10 and the annular magnet 31. Therefore, the sleeve 15 and the magnet 31 can be mechanically connected. Moreover, in the moving lens body 10, the sleeve 15 and the lens holder 14 are firmly connected via a screw mechanism. Therefore, according to the present embodiment, the magnet 31 can be fixed to the moving lens body 10 with sufficient strength, so that it is possible to reliably prevent the magnet 31 from being detached from the moving lens body 10 when an impact test is performed. . Further, according to the present embodiment, when the magnet 31 is fixed to the sleeve 15 of the moving lens body 10, it is not necessary to use any adhesive, so that the magnet 31 is affected by the shrinkage force when the adhesive is cured. Is not tilted on the moving lens body 10, and the magnet 31 is not displaced on the moving lens body 10. Therefore, the yield and reliability of the lens driving device 1 can be improved.

  In addition, when the magnet 31 is fixed to the sleeve 15 of the moving lens body 10, it is not necessary to use any adhesive, so that the manufacturing process can be simplified. Further, in the engagement mechanism 40 of this embodiment, the protrusion 310 protruding radially inward from the inner peripheral surface of the magnet 31 and the protrusion holding portion 41 extending in the circumferential direction on the sleeve 15 side are used. After the sleeve 15 of the lens body 10 is inserted inside the magnet 31, the protrusions 310 are clamped from both sides in the optical axis direction by the protrusion clamping portions 41 by simply rotating these members around the optical axis. As a result, assembly work is easy. Therefore, the productivity of the lens driving device 1 can be improved.

  Further, since the engaging mechanism 40 includes the protrusions 310 and the protrusion holding portions 41 at a plurality of positions in the circumferential direction, the magnet 31 engages with the sleeve 15 at a plurality of positions in the circumferential direction and has sufficient strength. Retained. Further, since the magnet 31 is engaged and held at a plurality of locations in the circumferential direction with respect to the sleeve 15, it is securely fixed at a predetermined position and securely fixed at a predetermined posture. Furthermore, the flange portion 150 that supports the protrusion 310 from one side in the optical axis direction in the protrusion holding portion 41 is formed over the entire circumferential direction and functions as a support surface that supports the entire inner peripheral edge of the magnet 31. Can be reliably supported and fixed in a posture orthogonal to the optical axis L.

  Further, in this embodiment, since the magnet 31 is fixed to the moving lens body 10, when the magnet 31 is manufactured, the protrusion 310 may be formed at the same time. Therefore, it is not necessary to change the structure of the members constituting the magnetic drive mechanism 30 significantly.

  Furthermore, the other side (the wall surface 153 of the lateral portion 152 of the stepped portion 151) that faces the both sides in the optical axis direction of the projection sandwiching portion 31 is a tapered surface that extends obliquely in the circumferential direction. Is more strongly clamped as it goes deeper into the protrusion clamping portion 41. Further, since the protrusion 310 is pressed against the flange portion 150 as it goes deeper into the protrusion holding portion 41, the magnet 31 can be reliably fixed in a posture orthogonal to the optical axis L.

(Other embodiments)
As shown in FIG. 2A, in a state where the magnet 31 is fixed to the sleeve 15, there is a protrusion between the portion where the protrusion 310 is not formed on the inner peripheral surface of the magnet 31 and the outer peripheral surface of the sleeve 15. A gap 18 having a length corresponding to the distance 310 is moved in the circumferential direction is formed. Therefore, the adhesive between the sleeve 15 and the magnet 31 may be reinforced by injecting an adhesive into the gap 18 and then curing the adhesive. Even in such a configuration, since the use of the adhesive is only auxiliary, the application work does not take much time. Further, since the amount of the adhesive to be applied is small, the magnet 31 does not tilt on the moving lens body 10 due to the shrinkage force when the adhesive is cured, and the magnet 31 is displaced on the moving lens body 10. There is no cause.

  In the above embodiment, the lens moving body 10 includes the sleeve 15 and the magnet 31 is fixed to the sleeve 15. However, the magnet 31 is directly attached to the outer peripheral surface of the lens holder 14 without using the sleeve 15. The present invention may be applied to a lens driving device to be fixed.

(A), (b) is the top view and longitudinal cross-sectional view of the lens drive device to which this invention is applied. (A), (b) is the perspective view which shows the state which fixed the magnet to the outer peripheral surface of the sleeve of a moving lens body in the lens drive device to which this invention is applied, and its exploded perspective view. FIG. 3 is a plan view of the sleeve shown in FIG. 2 and a plan view of the magnet shown in FIG. 2. It is explanatory drawing which shows the state which fixed the magnet to the outer peripheral surface of the sleeve of a moving lens body in the conventional lens drive device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens drive device 10 Moving lens bodies 11, 12, 13 Lens 14 Lens holder 15 Sleeve 20 Fixed body 30 Magnetic drive mechanism 31 Magnet 33 First stator coil 35 Second stator coil 40 Engagement mechanism 41 Projection clamping part 42 Projection Guide portion 150 Flange portion 151 Step portion 152 Step portion lateral portion 310 Protrusion

Claims (5)

In a lens driving device having a moving lens body movable in the optical axis direction on a fixed body, and a magnetic driving mechanism for moving the lens moving body along the optical axis,
The magnetic drive mechanism includes an annular magnet having a constant thickness fixed to the outer peripheral surface of the moving lens body, and a coil disposed on the fixed body side,
Wherein during the moving lens body and said magnet has engagement mechanism is configured to mechanically connecting the said moving lens body magnets,
The engaging mechanism includes a protrusion protruding in a radial direction from an inner peripheral surface of the magnet and a protrusion extending in a circumferential direction on the outer peripheral surface of the moving lens body, and the protrusion is rotated when the protrusion is rotated around the optical axis. A projection clamping part that clamps from both sides in the optical axis direction,
The lens driving device according to claim 1, wherein the protrusion has the same thickness as the magnet in the optical axis direction. The lens driving device according to claim 1, wherein the engagement mechanism includes the protrusion and the protrusion holding portion at a plurality of locations in a circumferential direction. 3. The engagement mechanism according to claim 2, wherein the engagement mechanism includes a protrusion guide portion on the other surface side for guiding the protrusion to the entrance of the protrusion holding portion when the movable lens body is inserted inside the magnet. A lens driving device. 4. The method according to claim 1, wherein one side of a portion of the protrusion sandwiching portion that faces the both sides in the optical axis direction is a support surface that is formed over the entire circumferential direction and supports the entire inner peripheral edge of the magnet. A lens driving device. 5. The other side of the portion that faces the both sides in the optical axis direction of the protrusion holding portion according to claim 4 extends obliquely in the circumferential direction so that the width dimension of the protrusion holding portion in the optical axis direction is wide on the entrance side and on the far side. A lens driving device having a tapered surface to be narrowed.

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