JP2016004253A - Lens driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily attach a spring to a lens support, in a lens driving device.SOLUTION: A lens driving device 1 includes a lens support 2, a cover 3 which stores the lens support 2, and a base 5 which supports the cover 3. Further, the lens driving device 1 includes a coil 41, a magnet 42, a first spring 43 which is arranged between the surface having an opening 30 of the cover 3 and the lens support 2, and a second spring 44 which is arranged between the lens support 2 and the base 5. The second spring 44 includes a leaf spring part 44b which applies an energizing force to the lens support 2 and a conduction part 44c which connects the leaf spring part 44b and the lens support 2 and supplies power to the coil 41. The lens support 2 includes a storage recess 24 which stores the end of a lead wire 41a derived from the coil 41. The end of the lead wire 41a and the conduction part 44c are electrically connected to each other by a conductive adhesive 45 in the storage recess 24.

Description

  The present invention relates to a lens driving device including a lens support that accommodates an optical system and an actuator that uses a VCM (Voice Coil Motor).

  In recent years, a small camera module used in a portable device such as a smartphone is equipped with an autofocus function. This autofocus function is realized by a lens driving device including a lens support that accommodates an optical member such as a lens, and an actuator that drives the lens support in the optical axis direction. A lens driving device using a VCM (Voice Coil Motor) as an actuator has a simple structure and can be easily reduced in size, and thus is suitably employed in the above-described small camera module (for example, Patent Document 1 and Patent Document 2).

  A general lens driving device using a VCM includes a lens support, a VCM, a spring that urges the lens support in the optical axis direction of the lens, and a main body that stores them. The main body includes a base and a yoke that covers the base from above, and the base and the yoke are each provided with an opening on the optical axis of the lens. The VCM includes a coil fixed to the outer periphery of the lens support and a magnet that applies a magnetic field to the coil, and the lens support is moved in the direction of the optical axis of the lens by electromagnetic force generated by flowing a current through the coil. Move to. In addition, in a lens driving device using a VCM, the lens support is held at a fixed position in a suspended state in the yoke using a spring when power is not supplied, and the lens support is held by the electromagnetic force generated by the coil during power supply. It is moved in the direction of the optical axis.

JP 2010-190923 A JP 2012-181384 A

  By the way, in the lens driving device using the VCM as described above (particularly, Patent Document 2), a spring that holds the lens support in a fixed position is connected to the coil, and power is supplied to the coil through the spring. The power supply mechanism to the coil is simplified. However, in this case, it is necessary to fix the spring and the coil (or the lead wire derived from the coil) with solder or the like. However, the mounting position of the spring greatly affects the position of the lens support, and if the position accuracy is not appropriate, the lens support may be tilted, causing the optical characteristics of the lens driving device to deteriorate. Can be. In recent years, with the increase in image quality of camera modules, a slight tilt of the lens support greatly reduces the performance of the autofocus function. For this reason, it is not easy to attach the spring in the lens driving device as described above, which causes a reduction in the production yield of the device.

  The present invention solves the above-described problems, and an object of the present invention is to provide a lens driving device capable of easily attaching a spring to a lens support.

  In order to solve the above problems, a lens driving device according to the present invention includes a lens support that contains an optical member that includes a lens, and a cover that contains the lens support and transmits an incident light to the lens. And a base that supports the cover, and a drive unit that moves the lens support in the optical axis direction of the lens, the drive unit being arranged around the lens support, and the coil A magnet for applying a magnetic field to the lens, a first spring disposed between the surface of the cover having the opening and the lens support, and a second spring disposed between the lens support and the base. The second spring includes a leaf spring portion that applies an urging force to the lens support, a guide that connects the leaf spring portion and the lens support and supplies power to the coil. The lens support has a receiving recess for receiving an end portion of the lead wire led out from the coil on a surface facing the base, and the end portion of the lead wire and the conductive portion The parts are electrically connected to each other by a conductive adhesive in the housing recess.

  In the lens driving device, the lens support has a lead-out portion for pulling out a lead wire led out from the coil to the housing recess at a position adjacent to the housing recess, and an end portion of the lead wire is located at the end of the lead wire. It is preferable that it is folded in the said accommodation recessed part side via the drawer | drawing-out part.

  In the lens driving device, it is preferable that the conductive adhesive is applied to the housing recess in which an end portion of the lead wire is housed, and the conductive portion has a plurality of minute holes.

  In the lens driving device, the lens support has a convex portion for positioning the second spring on a surface facing the base, and the conducting portion has a hole portion through which the convex portion is inserted. It is preferable to have.

  In the lens driving device, it is preferable that the magnet is disposed on an outer periphery of the coil, and the cover has a guide recess for positioning the magnet on a side surface standing from a surface having the opening.

  The lens driving device further includes a yoke that accommodates the cover, the first spring, and the magnet, and the magnet has a rectangular parallelepiped shape, is disposed in parallel with a side surface of the yoke, and is fitted into the guide recess. In this state, it is preferably fixed to the inner surface of the yoke by an adhesive.

  According to the present invention, since the end portion of the lead wire and the conducting portion of the second spring are simply adhered by the conductive adhesive, the attaching operation of the second spring to the lens support is easy, and the skill of the operator Therefore, the manufacturing yield can be improved.

FIG. 4A is a top perspective view of a lens driving device according to an embodiment of the present invention, and FIG. The disassembled perspective view of the said lens drive device. (A) thru | or (c) is a perspective view which shows the attachment procedure of the coil to the lens support body of the said lens drive device. (A) and (b) are perspective views which show the attachment procedure of the 2nd spring to the lens support body of the said lens drive device. FIG. 5 is a side sectional view corresponding to FIG. The lower perspective view of FIG. The bottom view of the said cover.

  A lens driving device according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1A, 1B, and 2, the lens driving device 1 of the present embodiment houses a lens support 2 that houses an optical member (not shown) including a lens, and a lens support 2. The cover 3 having the opening 30 that transmits the light incident on the lens, the drive unit 4 that moves the lens support 2 in the optical axis direction D of the lens, and the lens support 2 are mounted. And a supporting base 5.

  The lens support 2 includes a cylindrical portion 20 that holds the lens unit and a base portion 21 that supports the cylindrical portion 20. A threaded portion 22 is formed on the inner peripheral surface of the cylindrical portion 20, and is held by screwing the lens unit into the threaded portion 22. Further, the lens support 2 has convex portions 23 for positioning the first springs 43 on the four sides of the opening edge opposite to the base portion 21 of the cylindrical portion 20. The lens support 2 is formed of, for example, a plastic material.

  The cover 3 has a rectangular upper surface 31 having an opening 30 of the cover 3 and a side surface 32 erected on the base 5 side from the upper surface 31. On the side surface 32, a guide recess 33 for positioning the magnet 42 is formed. In addition, a concave portion 34 corresponding to the convex portion 23 of the lens support 2 is formed in the opening 30. The concave portion 34 prevents the convex portion 23 from contacting the upper surface 31 when the lens support 2 moves in the optical axis direction D. A guide that suppresses the rotation of the lens support 2 may be provided between the lens support 2 and the cover 3. Further, the upper surface 31 has an inner edge portion 35 (see FIG. 6 described later) protruding toward the base 5 side along the side surface 32. The inner edge portion 35 is formed so as to correspond to the outer edge shape of the first spring 43 (frame-like portion 43b described later).

  The drive unit 4 is an actuator that drives the lens support 2 by so-called VCM (Voice Coil Motor). The drive unit 4 includes a coil 41 disposed around the lens support 2, a magnet 42 that applies a magnetic field to the coil 41, and a cover 3. A first spring 43 disposed between the upper surface 31 having the opening 30 and the lens support 2, and a second spring 44 disposed between the lens support 2 and the base 5. The outer periphery of the lens support 2 is formed to have a substantially octagonal box shape, and the coil 41 is disposed on the outer periphery. Magnets 42 are respectively provided at positions corresponding to the four side surfaces of the lens support 2 on the outer periphery of the coil 41. Evenly arranged.

  The coil 41 is formed by winding and binding copper wires in the same direction, and lead wires 41a and 41b are led out from the start end and the end, respectively. The magnet 42 is a rectangular parallelepiped permanent magnet.

  The first spring 43 connects the annular part 43a in contact with the lens support 2, the frame part 43b in contact with the inner edge part 35 (see FIG. 6) of the cover 3, and the annular part 43a and the frame part 43b. And a wave-shaped spring portion 43c for applying an urging force to the lens support 2. In the annular portion 43a, a concave portion 43d corresponding to the convex portion 23 of the lens support 2 is formed.

  In the present embodiment, two second springs 44 are used and are individually electrically connected to the lead wires 41 a and 41 b led out from the coil 41. Each of the second springs 44 connects a base portion 44a that is in contact with the base 5, a partially arcuate plate spring portion 44b that applies a biasing force to the lens support 2, and the plate spring portion 44b and the lens support 2 and a coil. And a conduction portion 44 c that feeds power to the power supply 41. The second spring 44 has a power supply terminal 44d that extends from the base 44a and supplies power to the apparatus.

  The lens driving device 1 further includes a yoke 6 that houses the cover 3, the first spring 43, and the magnet 42. The yoke 6 is formed to have a box shape whose inner dimension is slightly larger than the outer dimension of the cover 3, and the upper surface 61 has an opening 60 and a concave shape corresponding to the opening 30 and the concave portion 34 of the cover 3, respectively. Part 62. The yoke 6 is formed of a magnetic material, and the magnet 42 is fixed to the side surface (inner surface 63) thereof as described later.

  The base 5 is a plate-like member having an opening 50 that transmits light emitted from the lens, and its outer shape is substantially the same as the shape of the yoke 6 viewed from below. The base 5 includes an engaging portion 51 that engages with the yoke 6 and a hole portion 52 for leading the power supply terminal 44d out of the apparatus. Further, the base is provided with a convex portion 53 for positioning the second spring 44, and the second spring 44 is provided with a hole portion 44e into which the convex portion 53 is fitted into the base portion 44a.

  As shown in FIG. 3A, the lens support 2 has a housing recess 24 that houses the ends of the lead wires 41 a and 41 b led out from the coil 41 on the surface of the base 21 that faces the base 5. Further, the lens support 2 has a lead-out portion 25 for drawing out the lead wires 41 a and 41 b led out from the coil 41 to the housing recess 24 at a position adjacent to the housing recess 24. The drawer portion 25 is formed by forming a part of the base portion 21 adjacent to the housing recess 24 into a groove shape. In addition, the drawer | drawing-out part 25 is not restricted to the groove shape of a figure example, For example, a hole shape may be sufficient.

  Further, as shown in FIG. 3B, the end portions of the lead wires 41 a and 41 b are folded toward the housing concave portion 24 via the lead portion 25. As a result, the end portions of the lead wires 41 a and 41 b can be temporarily held in the housing recess 24. And as shown in FIG.3 (c), the conductive adhesive 45 is apply | coated to the accommodation recessed part 24 in which the edge part of lead wire 41a, 41b was accommodated.

  As shown in FIGS. 4A and 5, two second springs 44 attached to the lens support 2 are prepared. The lens support 2 has a convex portion 26 for positioning the second spring 44 on the surface facing the base 5 of the base portion 21, and the convex portion 26 is inserted into the conducting portion 44 c of the second spring 44. It has a hole 44f. Then, as shown in FIG. 4B, two second springs 44 are placed on the lens support 2 so that the convex portion 26 fits into the hole 44f, and the conduction portion 44c of the second spring 44 is set. Then, the conductive adhesive 45 applied to the housing recess 24 is adhered to the ends of the lead wires 41 a and 41 b and the housing recess 24. As a result, the end portions of the lead wires 41 a and 41 b and the conducting portion 44 c of the second spring 44 are electrically connected to each other by the conductive adhesive 45 in the housing recess 24. As the conductive adhesive 45, for example, a conductive paste in which conductive metal fine particles are mixed with a synthetic resin such as a silver paste, a silicone resin, or an epoxy resin is used.

  In the conventional lens driving device, many man-hours are required for performing operations such as soldering and bonding of the springs, and the skill of the operator is required, resulting in a decrease in manufacturing yield. On the other hand, in the present embodiment, the solder connection as described above is not necessary, and the end portions of the lead wires 41a and 41b and the conductive portion 44c of the second spring 44 are simply bonded by the conductive adhesive 45. In addition, it is easy to attach the second spring 44 to the lens support 2, and it is possible to improve the manufacturing yield without the skill of the operator. Further, by simply placing the second spring 44 on the lens support 2 so that the convex portion 26 fits into the hole 44f, they can be joined in an accurate positional relationship. This embodiment is particularly preferably used in a lens driving device in which the coil 41 is provided on the inner peripheral side of the magnet 42 and uses a spring as a power feeding mechanism for the coil 41.

  In addition, the housing recess 24 is formed so as to satisfy the normal application capacity of the conductive adhesive 45. Therefore, for example, even when the conductive adhesive 45 is applied to the housing recess 24 so as to rise in a mountain shape, and the conductive portion 44c of the second spring 44 is placed thereon, the conductive adhesive 45 protrudes to the outside. There is nothing. As a result, for example, the conductive adhesive 45 used for joining one of the second springs 44 protrudes outside, and the conducting portion 44c and the base portion 44a are adhered to each other, so that the spring performance of the second spring 44 is lost. In addition, it is possible to suppress problems such as contact with the other second spring 44 and short-circuiting.

  Further, as shown in FIGS. 4A and 4B, the conductive portion 44c has a plurality of minute hole portions 44g in the portion to which the conductive adhesive 45 is bonded. The conductive adhesive 45 generates a small amount of gas at the time of curing, and may cause a conductive failure in which the resistance value at the time of conduction increases due to the influence of the gas. On the other hand, according to the present embodiment, the micropores 44g can discharge the dust from the cured adhesive portion, thereby suppressing the above-described poor conduction. Further, by providing the conductive portion 44c with a plurality of minute hole portions 44g, the bonding area between the conductive adhesive 45 and the conductive portion 44c is increased, and the adhesiveness thereof can be improved. Even when the conductive adhesive 45 is in an uncured state, the second spring 44 is positioned by the convex portion 26 of the lens support 2, so the positional relationship between the second spring 44 and the lens support 2. Can be prevented from shifting. Therefore, it is possible to obtain a highly reliable lens driving device 1 in which the mounting position accuracy of the second spring 44 with respect to the lens support 2 is appropriate.

  Here, the entire assembly procedure of the lens driving device 1 will be described with reference to FIGS. First, the cover 3 is fitted into the yoke 6, and then the first spring 43 and the magnet 42 are sequentially attached. A guide recess 33 for positioning the magnet 42 is provided on the side surface 32 of the cover 3. Thus, the magnet 42 is fitted in the guide recess 33, as shown in FIG. 42 is fixed to the inner surface of the yoke 6 by the adhesive 7 applied from above.

  For example, when a magnet is provided at each corner of the yoke, in order to fix the magnet, two points of adhesive are applied to each magnet in order to fix the magnet to the inner surface of the two surfaces of the yoke. There is a need to. On the other hand, in this embodiment, each magnet 42 is arranged in parallel with the side surface of the yoke 6 and is temporarily held by the guide recess 33 in the state before applying the adhesive 7 except for the direction of the base 5 side. Therefore, one point of the adhesive 7 may be applied to each magnet 42. Thereby, the attachment process of the magnet 42 can be reduced and productivity can be improved.

  In this way, the yoke 6 (and cover 3) side parts are assembled. Further, according to the procedure described with reference to FIGS. 3 and 4, the coil 41 and the second spring 44 are attached to the lens support 2, and these are mounted on the base 5 to assemble the base 5 side parts. And the lens drive device 1 is assembled by combining the yoke 6 side part and the base 5 side part.

  In addition, this invention is not restricted to the said embodiment, A various deformation | transformation is possible. In the above-described embodiment, the configuration in which the power feeding terminal 44d is led out from the base 5 side is shown. However, depending on the configuration of the device in which the lens driving device 1 is incorporated, for example, the power feeding terminal 44d may be led out from the yoke 6 side. . Further, the second spring 44 may be constituted by a single spring member as long as it can be electrically connected to the lead wires 41a and 42b led out from the coil 41, respectively.

DESCRIPTION OF SYMBOLS 1 Lens drive device 2 Lens support body 24 Accommodating recessed part 25 Drawer part 26 Convex part 3 Cover 33 Guide recessed part 4 Drive unit 41 Coil 41a Lead wire 41b Lead wire 42 Magnet 43 First spring 44 Second spring 44b Plate spring part 44c Conducting part 44f Hole 44g Micro hole 45 Conductive adhesive 5 Base 6 Yoke 7 Adhesive

Claims (6)

A lens support that contains an optical member including a lens; a cover that contains the lens support and has an opening that transmits incident light to the lens; a base that supports the cover; and the lens support that is a lens. A driving unit that moves in the direction of the optical axis of the lens, and a lens driving device comprising:
The drive unit is arranged between a coil disposed around the lens support, a magnet for applying a magnetic field to the coil, a surface of the cover having the opening, and the lens support. A spring, and a second spring disposed between the lens support and the base,
The second spring includes a leaf spring portion that applies a biasing force to the lens support, and a conduction portion that connects the leaf spring portion and the lens support and supplies power to the coil.
The lens support has an accommodation recess for accommodating an end portion of a lead wire led out from the coil on a surface facing the base.
An end portion of the lead wire and the conducting portion are electrically connected to each other by a conductive adhesive in the housing recess. The lens support has a lead-out portion for pulling out the lead wire led out from the coil to the housing recess at a position adjacent to the housing recess,
2. The lens driving device according to claim 1, wherein an end portion of the lead wire is folded into the housing concave portion through the lead-out portion. The conductive adhesive is applied to the housing recess in which an end of the lead wire is housed,
The lens driving device according to claim 1, wherein the conducting portion has a plurality of minute hole portions. The lens support has a convex portion for positioning the second spring on a surface facing the base,
4. The lens driving device according to claim 1, wherein the conducting portion has a hole portion through which the convex portion is inserted. 5. The magnet is disposed on an outer periphery of the coil;
The lens driving according to any one of claims 1 to 3, wherein the cover has a guide recess for positioning the magnet on a side surface standing from a surface having the opening. apparatus. A yoke for accommodating the cover, the first spring and the magnet;
6. The magnet according to claim 5, wherein the magnet has a rectangular parallelepiped shape, is disposed in parallel with the side surface of the yoke, and is fixed to the inner side surface of the yoke with an adhesive while being fitted in the guide recess. The lens driving device described.

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