JP2008026619A - Lens drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens drive device capable of reducing the inclination angle of a lens support in an arbitrary direction by means of springs that have fewer arms. <P>SOLUTION: In the lens drive device 1, the front spring 9 and rear spring 11 support the lens support 7 in a housing 2 so that the lens support 7 is freely movable in the direction of an optical axis. By electromagnetic force generated by supply of power to a coil 15, the lens support 7 is moved in the direction of the optical axis of a lens 8. Each of the springs 9 and 11 includes an outer ring 9b, 11b fixed to the housing 2, inner rings 9a, 11a fixed to the lens support 7, arms 9c, 11c connecting the outer and inner rings. The arms 9c, 11c are disposed at intervals in the direction of the circumference. The arms 9c of the spring 9 and the arms 11c of the spring 11 are located at different positions in the direction of the circumference. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lens driving device for autofocus used in a small camera.

  In this type of lens driving device, Patent Document 1 discloses that a front spring and a rear spring are provided between a lens support and a housing, and each spring includes an outer ring portion fixed to the housing, and a lens support. The structure which has the arm part which connects the inner ring part fixed to the body and the outer ring part and the inner ring part is disclosed. In this way, by providing the arm part between the inner ring part fixed to the lens support and the outer ring part fixed to the housing, the propulsive force acting on the lens support by the electromagnetic force and the biasing force of the arm part The lens support is moved so as to balance it.

  In the technique disclosed in Patent Document 1, each arm portion of the front spring and each arm portion of the rear spring are arranged at the same position in the circumferential direction.

  By the way, when shooting with the camera tilted upward or downward during camera shooting, the lens support tends to tilt with respect to the housing, but the elastic force of the arm part of the spring acts on the lens. The inclination angle of the support relative to the housing can be reduced.

JP 2006-58662 A

  However, when the tilt angle increases, the lens may be out of focus. In particular, the tilt of the camera does not always occur in a predetermined direction, and occurs at an arbitrary position in the peripheral direction of the lens support. Therefore, if the lens support is tilted away from the arm, the elastic force of the arm is reduced. There is a risk that it will not work sufficiently and may tilt significantly.

  In order to reduce the inclination of the lens support in various directions, it is conceivable to provide a large number of arms in the circumferential direction of the lens support. However, as the number of arms increases, the shape of the spring becomes complicated. It becomes difficult to adjust the balance with the driving force acting on the lens support.

  Therefore, an object of the present invention is to provide a lens driving device that can reduce the tilt angle of a lens support in an arbitrary direction with a spring having a small number of arm portions.

  The invention according to claim 1 is an annular yoke, a lens support that holds the lens and is disposed on the inner peripheral side of the yoke, a coil that is fixed to the outer periphery of the lens support, a magnet that is provided on the yoke, A plurality of springs and a housing are provided, and each spring is provided between the housing and the lens support to support the lens support so as to be movable in the direction of the optical axis with respect to the housing. The lens driving device moves the lens support in the direction of the optical axis of the lens by electromagnetic force generated as a result of which each spring has an outer ring fixed to the housing, an inner ring fixed to the lens support, an outer ring, It has an arm part that connects the ring part and the inner ring part, the arm part is arranged at intervals in the circumferential direction, and the position of the arm part in each spring is provided at a different position in the circumferential direction. It is characterized by.

  According to a second aspect of the present invention, in the first aspect of the invention, the plurality of springs are a front spring located on the subject side in the optical axis direction of the lens and a rear spring located behind the front spring. And a plurality of arm portions of each spring, and the arm portion of the rear spring is located at an intermediate position between adjacent arm portions of the front spring.

  The invention according to claim 3 is the invention according to claim 1, wherein each of the front spring and the rear spring has two arm portions, and each arm portion is provided at a position orthogonal to each other. To do.

  According to the first aspect of the present invention, the springs that support the lens support with respect to the housing are located at different positions in the circumferential direction, and therefore the number of arm portions provided on each spring is reduced. And many arrangement | positioning of the arm part in the circumferential direction can be taken as the whole some spring. Therefore, the number of arm portions of each spring can be reduced, and the tilt angle of the lens support in an arbitrary direction can be reduced.

  Since it is not necessary to increase the number of arm portions of each spring, the configuration of each spring can be simplified and the balance between the elastic force of the arm portion acting on the lens support and the propulsive force can be easily adjusted.

  Furthermore, the lens support can be elastically supported at a number of positions in the circumferential direction even when a significant external force is applied due to shaking, tilting or dropping when the camera equipped with the lens driving device is carried. It is possible to reduce external forces and vibrations acting on the lens and prevent damage to the lens support and the lens.

  According to the second aspect of the present invention, the effect of the first aspect can be obtained, and the arm portions of the front spring and the rear spring are arranged at equal intervals in the circumferential direction of the lens support. In addition, the lens support is not biased in the circumferential direction, and a uniform elastic force can be applied. Therefore, the lens support can be stably held with respect to the housing.

  According to the invention described in claim 3, since the function and effect described in claim 1 can be obtained and the lens support can be elastically held from four directions, the lens support can be formed with a minimum number of arms. The inclination angle can be reduced.

  Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is an exploded perspective view of the lens driving device according to the first embodiment of the present invention, and FIG. 2 is a perspective view showing the front spring and the rear spring shown in FIG. FIG. 3 is a longitudinal view of the lens driving device cut along a diagonal line.

  A lens driving device 1 according to the present embodiment is a lens driving device for an autofocus camera incorporated in a mobile phone. This lens driving device 1 is disposed on the rear side of the annular yoke 3, the magnet 13 disposed in the yoke 3, the lens support 7, the front spring 9, the rear spring 11, and the yoke 3. A base 5 (housing) and a frame (housing) 6 disposed on the front side of the yoke 3 are provided, and a coil 15 is fixed to the outer periphery of the lens support 7. An insulator (spacer) 17 is disposed between the yoke 3 and the rear spring 11.

  The yoke 3 has a square shape in plan view when viewed from the front side, and has a circular shape when viewed from the inside. The outer peripheral wall 3a, the inner peripheral wall 3b, and the outer peripheral wall 3a and the inner peripheral wall 3b are connected with a space therebetween. The outer peripheral wall 3a, the inner peripheral wall 3b, and the connecting wall 3c have a U-shaped cross section.

  At each corner 14 of the outer peripheral wall 3a of the yoke 3, a magnet 13 is fixed to the inner peripheral surface of the outer peripheral wall 3a.

  The lens support 7 has a cylindrical shape, holds a lens 8 (see FIG. 3) on its inner periphery, and is provided on the inner periphery of the yoke 3 so as to be movable in the optical axis X direction. A coil 15 is mounted on the outer peripheral surface of the lens support 7, and the coil 15 is bonded and fixed to a coil fixing portion 19 provided integrally with the lens support 7. The coil fixing portions 19 are arranged at intervals in the circumferential direction of the outer peripheral surface of the lens support 7.

  The coil 15 is located in the yoke 3 between the magnet 13 and the inner peripheral wall 3b, and moves in the yoke 3 in the optical axis X direction (front-rear direction) of the lens.

  The base 5 has an outer wall 5 a located on the outer periphery of the yoke 3 and a base portion 5 b located on the rear side of the yoke 3 (rear side in the optical axis X direction of the lens). The outer peripheral side portion 11b of the rear spring 11 is placed.

  The front spring 9 is an annular leaf spring, and is provided with an inner peripheral side portion 9a, an outer peripheral side portion 9b, and an arm portion 9c that connects the inner peripheral side portion 9a and the outer peripheral side portion 9b and can be elastically deformed. . The inner peripheral side portion 9a has a circular shape, the outer peripheral side portion 9b has a quadrangular shape, and the arm portions 9c are provided so as to be opposed to the positions of the diagonal corner portions. The arm portion 9c arranges the meandering intermediate portion 12 in a space between the arc of the inner peripheral side portion 9a and the corner portion of the outer peripheral side portion 9b, and a connecting portion 16 between the arm portion 9c and the inner peripheral side portion 9a, The connecting portion 18 between the arm portion 9c and the outer peripheral side portion 9b is provided at a position away from the corner of the outer peripheral side portion 9b in opposite directions.

  The inner peripheral side portion 9 a is attached to the front end (tip) of the lens support 7, and the outer peripheral side portion 9 b is sandwiched and fixed between the yoke 3 and the frame 6.

  As shown in FIG. 2, the rear spring 11 is a leaf spring that is formed in a ring shape with substantially the same shape as the front spring 9 as a whole, but in the present embodiment, one side 30 and the other side divided into left and right parts. 32. The outer peripheral side portions 11 b and 11 b of the rear spring 11 are sandwiched between the base 5 and the yoke 3 via an insulator (spacer) 17, and the insulator 17 is formed between the rear spring 11 and the yoke 3. The electrical insulation between them is intended. The inner peripheral side portions 11 a and 11 a are attached to the rear end of the lens support 7. Each inner peripheral side portion 11a and outer peripheral side portion 11b of the rear spring 11 are connected by an elastically deformable arm portion 11c. Two arm portions 11c are provided at the positions of the diagonal corners.

  The arm portions 11c, 11c of the rear spring 11 and the arm portions 9c of the front spring 9 are arranged at positions orthogonal to each other when viewed from the optical axis X direction of the lens in the assembled state.

  Like the front spring 9, the arm portion 11c has a meandering intermediate portion 22 arranged in a space between the arc of the inner peripheral side portion 11a and the corner portion of the outer peripheral side portion 11b, and the arm portion 11c and the inner peripheral side portion 11a. The connecting portion 24 and the connecting portion 26 between the arm portion 11c and the outer peripheral side portion 11b are provided at positions away from the corners of the outer peripheral side portion 11b in opposite directions.

  In the present embodiment, a terminal 33 is formed on one side 30 constituting the rear spring 11, and a terminal 35 is formed on the other side 32, and each terminal 33, 35 is connected to a power supply terminal. It has come to be. The one side portion 30 and the other side portion 32 are electrically connected to the coil 15 by soldering or the like, respectively, and the coil 15 is energized from the rear spring 11.

  The front spring 9 and the rear spring 11 are flat in a natural state before assembly (a state before the frame 6 is assembled) (see FIG. 1), but at least the front spring 9 is not illustrated after the assembly. As shown in FIG. 3, the arm portion 9c is attached in an elastically deformed state so that the inner peripheral side portion 9a is positioned in front of the outer peripheral side portion 9b. As a result, the inner peripheral side portion 9a constantly urges the lens support 7 with the urging force directed toward the base 5 by the restoring force (elastic force) of the spring.

  The frame 6 is disposed on the front side of the lens support 7, holds the outer peripheral side portion 9 b of the front spring 9 between the yoke 3, and fits and fixes to the base 5 to fix the base 5 and the frame 6. A housing 2 (see FIG. 3) is formed.

  Next, operations and effects of the lens driving device 1 according to the present invention will be described. According to the lens driving device 1 according to the present embodiment, when the coil 15 is energized from the terminals 33 and 35, the lens support 7 is biased by the front spring 9 and the rear spring 11 by the electromagnetic force acting on the coil 15. And stops at a position where the forces of the springs 9 and 11 are balanced.

  The front spring 9 and the rear spring 11 have only two arm portions 9c, 11c, and it is easy to adjust the urging force acting in the moving direction of the lens support 7, so that the lens support 7 It is easy to adjust the balance between the propulsive force due to the electromagnetic force acting on the elastic force of the arms 9c and 11c.

  When the camera is photographed with the camera facing obliquely upward or downward, the lens support may be greatly inclined with respect to the housing 2 and the lens 8 may be out of focus. Since the arm portions 9c and 11c are arranged at different positions in the circumferential direction on the lens support body 7 with the spring 11, the arrangement of the arm portions 9c and 11c in the circumferential direction is large as the whole of the two springs 9 and 11. Can take. Therefore, even if the number of arm portions 9c, 11c of each spring 9, 11 is small, the inclination angle of the lens support 7 in any direction can be reduced. Further, since the number of arm portions 9c, 11c of each spring 9, 11 can be reduced, the configuration of each spring 9, 11 can be simplified.

  Furthermore, even when a significant external force is applied due to shaking or tilting of the camera equipped with the lens driving device 1 when it is carried, or dropping, the arm portions 9c and 11c are elastic at many positions in the circumferential direction. Therefore, it is possible to reduce the external force and shaking in any direction acting on the lens support and prevent the lens support 7 and the lens 8 from being damaged.

  In the present embodiment, since the arm portions 9c and 11c are arranged at equal intervals in the circumferential direction of the lens support 7, the lens support 7 can be applied with a uniform elastic force without being biased. Can be kept stable.

  In particular, the arm portions 9c and 11c are positioned at right angles to each other, and the lens support body can be elastically held from four directions, so that the inclination angle of the lens support body 7 can be reduced with the minimum number of arm portions 9c and 11c. .

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

  For example, the front side spring 9 and the rear side spring 11 may be simply replaced by using the same one as the conventional one. In this case, the number of arm portions 9c and 11c does not change, and the balance adjustment with the propulsive force acting on the lens support is not necessary.

  As shown in FIG. 4, when the front spring 9 and the rear spring 11 are each provided with three arm portions 9c, 11c at equal intervals (120 degrees) and these springs 9, 11 are assembled. A total of six arms 9c and 11c may be equally spaced (60 degrees apart) in the circumferential direction.

  Similarly, as shown in FIG. 5, when the front spring 9 and the rear spring 11 are arranged with four arm portions 9 c and 11 c at right angles, and these springs 9 and 11 are assembled. In addition, a total of eight arm portions 9c and 11c may be equally spaced in the circumferential direction (45 degree intervals).

  4 and 5 show the arrangement of the arm portions 9c and 11c in the springs 9 and 11, and the inner ring portions 9a and 11a and the outer ring portions 9b and 11b are schematically illustrated.

  Both the outer ring portions of the front spring 9 and the rear spring 11 may be circular, and the shape is not limited.

It is a disassembled perspective view of the lens drive device concerning a 1st embodiment of the present invention. It is a perspective view which extracts and shows the front side spring and rear side spring which are shown in FIG. 1 in the position of an assembly | attachment state. It is the longitudinal view which cut | disconnected the lens drive device with the diagonal line. It is a top view which shows schematic structure of the spring concerning other embodiment, (a) is a front side spring, (b) is a figure of a rear side spring. It is a top view which shows schematic structure of the spring concerning other embodiment, (a) is a front side spring, (b) is a figure of a rear side spring.

Explanation of symbols

1 Lens driving device 3 Yoke 5 Base (housing)
6 frame (housing)
7 Lens Support 9 Front Spring 9a Inner Ring 9b Outer Ring 9c Arm 11 Rear Spring 11a Inner Ring 11b Outer Ring 11c Arm 13 Magnet 15 Coil

Claims (3)

  An annular yoke, a lens support holding the lens and disposed on the inner periphery of the yoke, a coil fixed to the outer periphery of the lens support, a magnet provided on the yoke, a plurality of springs, and a housing Each spring is provided between the housing and the lens support, and supports the lens support so as to be movable in the optical axis direction with respect to the housing. The lens support is generated by electromagnetic force generated by energizing the coil. Is a lens drive device that moves in the direction of the optical axis of the lens, each spring connecting the outer ring part fixed to the housing, the inner ring part fixed to the lens support, the outer ring part and the inner ring part A lens driving device, wherein the arm portions are arranged at intervals in the circumferential direction, and the positions of the arm portions in each spring are provided at different positions in the circumferential direction.   The plurality of springs are two springs, a front spring located on the subject side in the optical axis direction of the lens and a rear spring located on the rear side of the front spring, and a plurality of arm portions of each spring are provided. 2. The lens driving device according to claim 1, wherein the arm portion of the rear spring is positioned at an intermediate position between adjacent arm portions of the front spring. The lens driving device according to claim 2, wherein each of the front spring and the rear spring has two arm portions, and each arm portion is provided at a position orthogonal to each other.

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