JP2007047684A - Lens driving device and mobil phone terminal with camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain the appropriate posture of a lens to an optical axis when performing focusing operation in a lens driving device where actuators are arranged asymmetrically with the center of the lens. <P>SOLUTION: The lens driving device is provided with: a movable part capable of moving in the optical axis direction of the lens while holding the lens; a fixed part in which the movable part is housed; driving mechanisms arranged asymmetrically with the center of the lens and moving the movable part in the optical axis direction; and a plurality of elastic members whose one-side ends and the other-side ends are respectively connected to the movable part and the fixed part. Then, it is constituted so that the center of thrust of the driving mechanism may be positioned within a range set by linking the respective fixed spots of the movable part and the plurality of elastic members on a plane nearly orthogonal to the optical axis. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a small lens driving device capable of moving a lens in an optical axis direction, and a camera-equipped mobile phone terminal using the lens driving device.

  2. Description of the Related Art Conventionally, for example, a camera-equipped mobile phone terminal is known as a camera-equipped mobile device using a lens driving device. Generally, in such a mobile phone terminal with a camera, the camera function is often used with an unstable posture, such as taking a picture of a subject with the mobile phone terminal with one hand.

Therefore, as a countermeasure when the camera function is used in an unstable posture, a lens unit including a lens used in an AF (autofocus) lens driving device is sandwiched using two link plates, A technique for stabilizing the movement of the lens unit in the optical axis direction is known (see, for example, Patent Document 1).
JP 2004-333955 A

  In recent years, mobile phone terminals with cameras have been required to be smaller and thinner due to the convenience of carrying, etc. Naturally, the lens driving device used for mobile phone terminals with cameras is also downsized, Thinning is required.

  However, since the lens driving device disclosed in Patent Document 1 employs a configuration in which the lens unit is sandwiched between two link plates, a space for arranging the two link plates is provided in the lens driving device. It is necessary to secure. In addition, since a drive mechanism (actuator) is arranged around the lens unit so as to be symmetric with respect to the center of the lens, a certain space is required for installing the actuator in a plane direction perpendicular to the optical axis of the lens. Become. As a result, there is a problem that the lens driving device is thick and large, and the mobile phone terminal with a camera using the lens driving device is thick and large.

  In order to reduce the thickness and size of the lens driving device, the present applicant arranges an actuator for moving the movable lens barrel holding the lens in only one direction on the XY plane orthogonal to the lens optical axis, and the XY plane. A lens driving device has been devised in which the elastic member is arranged in the other direction.

  FIG. 7 is a top view of the devised lens driving device, showing an example in which two actuators are mounted to drive both sides. 8 is a cross-sectional view taken along the line BB passing through the center of the lens of the lens driving device shown in FIG.

  This lens driving device is composed of a movable portion, a fixed portion, and an elastic member that connects them, and the movable portion can move in the optical axis direction by a moving magnet type linear drive.

  The movable part side holds a lens 204 and moves a movable lens barrel 203 and a magnet 206 made of a lens fixed cylinder 205 movable in the direction of the optical axis F. The fixed part side is a fixed holder 202 and a yoke for housing the movable lens barrel 203. 207 and a coil 208, which are connected by an elastic member 209. The magnet 206, the yoke 207, and the coil 208 constitute a drive mechanism (actuator) that moves the movable lens barrel 203, and this lens drive device is provided with two actuators.

  The movable lens barrel 203 is composed of a lens fixing cylinder 205 that houses a plurality of lenses therein, and a magnet 206 is attached and fixed to the lower part of the lens fixing cylinder 205 on the XY plane of a cylindrical surface. A collar 205a is formed.

  The fixed holder 202 includes a substantially square bottom portion and a peripheral wall portion along the periphery of the bottom portion. The fixed holder 202 has an opening on the upper side, and houses the movable lens barrel 203, the actuator, and the elastic member 209 therein.

  The four elastic members 209 are constituted by plate-like elastic bodies (plate springs). One end of each elastic member 209 is located at each position of the outer wall of the movable lens barrel 203 and the other end is located near the four corners of the fixed holder 202. It is fixed. The four elastic members 209 have a meandering shape in the same plane (XY plane).

  The actuator is provided in one direction on the XY plane perpendicular to the optical axis F in a space sandwiched between the substantially bowl-shaped (square) fixed holder 202 and the movable lens barrel 203. In the example of FIG. 7, two actuators are provided on both sides in the X-axis direction of the movable lens barrel 203 and are driven on both sides.

  In the lens driving device configured as described above, when an electric current is passed through the coil 208, an upward thrust parallel to the optical axis F is generated in the two magnets 206, and the movable barrel 203 is fixed to the fixed portion (fixed holder 202). ) In the direction of the optical axis F (focusing operation) in a state where the operation restriction by the elastic member 209 is maintained.

  In the example of FIG. 7, since the components are arranged symmetrically around the lens 204, the movable lens barrel 203 can operate while maintaining a posture perpendicular to the optical axis F during focus driving. ing. That is, the elastic force (also referred to as “spring force” or “reaction force”) center 212 of the elastic member 209, the weight center 213 of the movable lens barrel 203, and the thrust center 214 of the actuator are coincident (on the optical axis F). Therefore, the vertical posture with respect to the optical axis F is maintained throughout the focus operation.

  As described above, from the viewpoint of maintaining the operation posture during the movement of the movable lens barrel 203, it is preferable that the actuators have two or more symmetrical arrangements.

  However, actuators, particularly magnets, that occupy the lens driving device have a high unit price ratio, and are one of the components that want to reduce the number of uses as much as possible in order to reduce the cost of the lens driving device.

  In view of the above cost reduction, the present applicant has devised a lens driving device having only one actuator.

  FIG. 9 is a top view of a lens driving device having one actuator. 10 is a cross-sectional view taken along the line CC passing through the center of the lens of the lens driving device shown in FIG.

  9 is different from the lens driving device shown in FIG. 7 in that one of the two arranged actuators is removed and a one-side driving lens driving device using one actuator is obtained. .

  However, when the actuator is disposed only on one side of the lens driving device, the center of the elastic force (also referred to as “spring force” or “reaction force”) of the elastic member 209, the weight center of the movable lens barrel 203, and the position of the thrust center of the actuator The relationship breaks down, making it impossible to operate ideally.

  Specifically, as shown in FIGS. 9 and 10, the positions of the elastic force center 212 of the elastic member 209 and the weight center 213 of the movable lens barrel 203 do not change from the lens center line, and the movable lens barrels 203 and 4 are not changed. The elastic members 209 are placed in a spring fixing range 211 connecting the fixing points 209a, 209b, 209c, and 209d. However, in the case of a one-side drive actuator, the thrust center 224 is biased, and the thrust center 224 deviates from the spring fixing range 210 and is positioned at the approximate center of the magnet 224.

  FIG. 11 shows a state during the focusing operation of the lens driving device shown in FIGS. As shown in FIG. 11, when a current is supplied to the coil 208 and the actuator is driven to cause the movable lens barrel 203 to perform a focusing operation, the elastic force moment Mk generated by the elastic force k acting on the elastic force center 212, the movable lens barrel 203 The gravity moment Mg generated by the gravity g acting on the gravity center 213 and the thrust f acting on the thrust center 224 generate a thrust moment Mf, which is not a translational motion in the direction of the optical axis F, but a rotation (counterclockwise in the figure). exercise.

  As a result, a part of the movable lens barrel 203, for example, the upper end edge of the movable lens barrel 203 interferes with the top surface component 230 made of light-transmitting resin disposed above the lens driving device. That is, the movable lens barrel 203 abuts the top surface component 30 in a state where the optical axis F of the lens 4 and the top surface component 230 are not perpendicular to each other to stop the focus operation (movement), and a lens tilt θ is generated. When the lens tilt θ is generated, there is a problem that the image quality is deteriorated, for example, the optical characteristic (resolution) is changed when the focus operation is performed.

  In particular, in the case of a small camera module, the influence of the lens tilt on the image sensor (image quality) is greater than that in the case of a large camera module.

  The present invention has been made in view of such a point, and in a lens driving device in which an actuator is arranged asymmetrically with respect to the center of the lens, an appropriate posture with respect to the optical axis of the lens during a focusing operation is maintained. Objective.

  In order to solve the above problems, the present invention is arranged asymmetrically with respect to the center of the lens, a movable portion that holds the lens and is movable in the optical axis direction of the lens, a fixed portion that houses the movable portion. A driving mechanism for moving the movable part in the optical axis direction, and a plurality of elastic members having one end and the other end connected to the movable part and the fixed part, respectively, and the thrust of the driving mechanism in a plane substantially orthogonal to the optical axis The center is configured to be located within a range connecting the fixed portions of the movable portion and the plurality of elastic members.

  According to the above configuration, since the thrust center of the drive mechanism is arranged within the range connecting the fixed portions of the movable part and the plurality of elastic members, the center of gravity of the movable part and the elastic force of the elastic member are arranged. The amount of moment generated between the center and the thrust center of the drive mechanism can be reduced. Thereby, the rotational movement of the movable part is suppressed, and the inclination of the lens with respect to the optical axis during the focusing operation is suppressed.

  According to the present invention, since the tilt with respect to the optical axis of the lens during the focusing operation can be suppressed, it is possible to provide a lens driving device capable of performing the focusing operation while maintaining an appropriate posture with respect to the optical axis of the lens.

  In addition, the reduction of parts (the drive mechanism becomes asymmetric with respect to the lens center) solves the problem that the posture of the lens cannot be maintained because the movable part does not translate, thereby reducing parts and reducing costs. can do. Further, the apparatus can be reduced in size by reducing the number of parts.

  In addition, when the lens driving device according to the present invention is applied to a mobile device such as a mobile phone terminal, it can contribute to a reduction in size and thickness of the mobile device.

  Hereinafter, an example of the best mode for carrying out the lens driving device for a camera module according to the present invention will be described with reference to FIGS.

  FIG. 1 is a top view of a lens driving apparatus according to an embodiment of the present invention. A lens driving device 1 shown in FIG. 1 includes a movable portion, a fixed portion, and an elastic member that connects them, and the movable portion can move in the optical axis direction by moving magnet type linear drive. Here, the optical axis is an axis when light is incident at an angle substantially perpendicular to an imaging surface of an imaging element (not shown).

  The movable part side holds a lens 4 having a plurality of lens members and can move in the direction of the optical axis F and can move in the direction of the optical axis F. 3, a fixed holder 2 that houses 3, a yoke 7, and a coil 8, which are connected by four plate-like elastic members (plate springs) 9.

  The movable barrel 3 in this example is asymmetric with respect to the center 4a of the lens 4 and is symmetric with respect to the X axis.

  One end of each elastic member 9 is fixed at a predetermined position on the outer wall of the movable lens barrel 3, and the other end is fixed at a predetermined position on the fixed holder 2, and the movable lens barrel 3 and the fixed holder 2 are connected. .

In order to obtain an appropriate focus sensitivity of the lens driving device, a mutual balance between the thrust constant of the thrust (driving force) generated by the actuator and the spring constant of the elastic member 9 that restricts the operation by the driving force is important. . In this example, since only one actuator is used, the thrust constant is low. Therefore, it is necessary to lower the spring constant (soften the spring) accordingly, and in order to increase the effective length of the elastic member 9 in a limited space, the elastic member 9
Are formed in a meandering shape in the same plane (XY plane).

  The magnet 6, the yoke 7, and the coil 8 constitute a magnetic circuit unit and function as a drive mechanism (actuator) that moves the movable barrel 3 in the direction of the optical axis F. The actuator is installed in such a state as to penetrate through the hole 10 provided in the movable barrel 3.

  In the lens driving device 1, since there is only one actuator, the thrust center 14 by the actuator deviates from the weight center 13 of the movable barrel 3 in a plane substantially orthogonal to the optical axis F. It is housed in a spring fixing range 11 connecting the fixing portions 9a, 9b, 9c, 9d with the elastic member 9. At this time, the center 12 of the elastic force by the four elastic members 9 is preferably closer to the weight center 13 of the movable barrel 3.

  FIG. 2 is a cross-sectional view taken along the line AA of the lens driving device 1 shown in FIG. 1, and shows a state during the focusing operation. As shown in FIG. 2, in the lens driving device 1, a movable barrel 3 and an actuator having a magnetic circuit configuration are housed in a substantially box-shaped fixed holder 2. The fixed portions 9a to 9d between each elastic member 9 and the movable lens barrel 3 are arranged in one plane at the initial position before the focusing operation. Here, the term “in one plane” refers to a plane that is substantially perpendicular to the optical axis and has substantially the same height from the bottom of the fixed holder 2.

  The movable lens barrel 3 is composed of a resin lens-fixing cylinder portion 5 having a cylindrical space for fixing the lens 4 therein, and a flange portion 5a is formed in the lower portion of the lens-fixation cylinder portion 5. ing. A magnet 6 is placed and fixed on the flange 5a. Inside the lens fixing cylindrical portion 5, a lens 4 and an intermediate member 24 as a spacer are arranged.

  The lens 4 is a photographing lens of a camera and is configured by combining a plurality of lens members. The subject-side lens member 22 is disposed on the upper side in FIG. 2, and the camera body-side lens member 23 is disposed on the lower side. In the lens driving device 1 of the present example, the movable lens barrel 3 is composed of a plurality of members, that is, the lens 4, the lens fixing cylindrical portion 5, and the intermediate member 28. Of these, a plurality of members or all members are included. May be configured integrally with the same member.

  The subject side lens member 22 has a circular lens portion having a lens function in the center, and a holder portion (not shown) for holding and supporting the lens portion on the outer periphery. The holder part is in contact with the intermediate member 24. The camera body side lens member 23 has a lens portion having a lens function at the center, and a holder portion (not shown) for holding and supporting the lens portion on the outer periphery. The holder portion of the camera body side lens member 23 is also in contact with the intermediate member 24.

  The lens portions of the subject side lens member 22 and the camera body side lens member 23 are aspherical lenses made of resin, and the lens portion and the holder portion are formed by integral molding of resin.

  The intermediate member 24 is a substantially annular member such as a donut having a hole 25 in the center. The intermediate member 24 keeps the distance between the subject side lens member 22 and the camera body side lens member 23 constant. Due to the presence of the intermediate member 24, the attaching operation and the positioning operation of the subject side lens member 22 and the camera body side lens member 23 are simplified.

  A circular incident window 21 is formed on the front surface (upper side of FIG. 2) of the lens fixing cylindrical portion 5 so as to capture the reflected light from the subject into the lens fixing cylindrical portion 5.

  The substantially box-shaped fixed holder 2 includes a substantially square bottom portion and a peripheral wall portion along the periphery of the bottom portion, and has an opening on the upper side. The movable barrel 3, the actuator, and the elastic member 9 are accommodated therein. To do.

  Above the lens driving device 1, a top surface component 30 having a circular incident window 31 for taking light into the lens driving device 1 is disposed.

  An image sensor (not shown) is installed behind the lens driving device 1 (below the fixed holder 2 in FIG. 2). Light incident from the entrance window 31 of the top surface component 30 is taken into the interior from the entrance window 21 of the lens driving device 1, passes through the lens 4, and passes through a hole (not shown) provided at the bottom of the fixed holder 2. Then, the surface of the image sensor is irradiated and a subject image is captured. This image sensor may be installed on the bottom surface of the fixed holder 2.

  An actuator for moving the movable lens barrel 3 in the direction of the optical axis F of the lens 4 is provided in one direction on the XY plane orthogonal to the optical axis F so as to penetrate through the hole 10 provided in the movable lens barrel 3. It is done. In the example of FIG. 1, one actuator is provided on one side of the movable barrel 3 in the X-axis direction, and the movable barrel 3 is moved by one-side driving.

  The yoke 7 constituting the actuator is erected on the bottom of the fixed holder 2, and the coil 8 is provided on the inner side (lens center 4 a side). The magnet 6 placed on the flange portion 5a of the lens fixing cylindrical portion 5 is disposed opposite to the coil 8 to constitute a magnetic circuit in the lens driving mechanism. The actuator generates an electromagnetic attractive force or an electromagnetic repulsive force between the coil 8 and the magnet 6 of the electromagnetic member, and applies a driving force in the direction of the optical axis F to the movable lens barrel 3.

  In the lens driving device 1 configured as described above, when an electric current is passed through the coil 8, an upward thrust parallel to the optical axis F is generated in one magnet 6, and the movable lens barrel 3 moves against the fixed holder 2. In this state, the movement of the elastic member 9 is maintained (focusing operation) in the direction of the optical axis F.

  In the lens driving device 1, an actuator is disposed inside the movable lens barrel 3 to shift the thrust center 14 toward the lens center 4 a. Since the thrust center 14 of the actuator is configured to be within the spring fixing range 11 connecting the fixing portions 9a to 9d between the movable barrel 3 and the elastic members 9 in a plane substantially orthogonal to the optical axis F. The thrust center 14, the elastic force center 12 of the elastic member 9, and the weight center of the movable lens barrel 3 approach each other.

  As a result, the amount of moment generated between the elastic force moment caused by the elastic force k1 acting on the elastic force center 12, the gravity moment caused by the gravity g1 acting on the weight center 13 and the thrust moment caused by the thrust f1 acting on the thrust center 14 is suppressed. Thus, the stable focusing operation of the movable barrel 3 becomes possible. Compared to the conventional symmetrical form (both sides drive) and single side drive, the lens tilt during the focusing operation can be suppressed.

  Further, in this example, the movable lens barrel 3 is asymmetric with respect to the lens center 4 a, and the weight center 13 is brought close to the thrust center 14. Thereby, since the elastic force center 12, the weight center 13, and the thrust center 14 approach or coincide with each other, the amount of moment generated mutually at each center position can be suppressed. In other words, the tilt of the lens 4 with respect to the optical axis F during the focusing operation can be suppressed.

  Therefore, the movable lens barrel 3 can perform an almost ideal translational motion with a reduced moment amount, and can be moved in the direction of the optical axis F while maintaining the posture of the lens 4 during the focusing operation. it can.

  Next, another embodiment of the camera driving device according to the present invention will be described with reference to FIGS. 3 and 4, the same reference numerals are given to the portions corresponding to those in FIGS. 1 and 2, and description thereof is omitted.

  FIG. 3 is a top view of a lens driving device according to another embodiment of the present invention. 4 is a cross-sectional view taken along line BB of the lens driving device 1 shown in FIG. The lens driving device of this example has a configuration in which a weight 15 is additionally provided on the outer wall of the movable barrel 3 on the actuator side with respect to the lens driving device 1 shown in FIG.

  By providing the weight 15 in the movable lens barrel 3, the weight center 33 of the movable lens barrel 3 can be shifted toward the thrust center 14, and can be made closer to the elastic force center 12 and the thrust center 14. Thereby, the movable lens barrel 3 can be moved in the direction of the optical axis F while maintaining the posture of the lens 4 more stably during the focusing operation.

  According to the lens driving device 1 having the above-described configuration, the posture of the lens 4 at the time of the focusing operation can be appropriately maintained, so that it is possible to prevent deterioration of optical characteristics (resolution) when the movable lens barrel 3 is focused.

  Further, by reducing the number of parts and using only one actuator (one-side drive), even when the actuator is asymmetrically arranged with respect to the lens center 4a, the elastic force center 12 of the elastic member 9, the movable lens barrel 3, the position of the weight center 13 (33) 3 and the thrust center 14 of the actuator can be brought close to each other, so that the posture of the lens 4 during the focusing operation with respect to the optical axis can be properly maintained.

  Therefore, since the problem caused by the reduction of parts is solved, the number of parts can be reduced by arranging the actuators asymmetrically, and the thickness and size can be reduced as compared with the conventional lens driving device.

  Further, by reducing the number of parts, an empty space (FIG. 1; opposite to the magnet 6 across the movable lens barrel 3) is created in the lens driving device, and the lens driving device can be further miniaturized. In addition, since a new space is created in the part where the parts are reduced, the degree of freedom in design is improved.

  Next, an example in which the lens driving device 1 described above is mounted on a mobile phone terminal as an example of a mobile device will be described.

  FIG. 5 is a perspective view of a camera-equipped mobile phone terminal to which the lens driving device according to the present invention is attached. As shown in FIG. 5, the camera-equipped mobile phone terminal 100 includes a lower housing 101 in which operation buttons (operation units) are arranged, and an upper housing 102 in which a portion for displaying an image captured by the camera is formed on the back surface. It consists of. By sliding or folding the upper housing 102 so as to match the lower housing 101, a compact size convenient for carrying can be obtained. When shooting using the camera function, as shown in FIG. 5, the lower casing 101 and the upper casing 102 are used in a shifted state.

  A hole for embedding the lens driving device 1 is formed in the back surface of the upper housing 102 of the camera-equipped mobile phone terminal 100. The lens driving device 1 is attached to the hole so that the incident window 21 formed in the lens fixing cylindrical portion 5 faces the subject. After the lens driving device 1 is attached, the lens driving device 1 is installed so as to cover the transparent resin top surface component 30 as shown in FIGS.

  According to the camera-equipped mobile phone terminal 100 of this example, since the thin and small lens driving device 1 is used, the thickness of the upper housing 102 can be reduced. As a result, when the lower casing 101 and the upper casing 102 are matched, the overall thickness of the camera-equipped mobile phone terminal can be reduced, so that the camera-equipped mobile phone terminal 100 can be made smaller and thinner. Can do.

  The mobile phone terminal to which the lens driving device 1 is applied is not limited to this example. For example, a so-called stick-type mobile phone terminal in which the display unit and the operation unit are integrated may be used. .

  The system configuration of the camera 120 including the lens driving device 1 of the camera-equipped mobile phone terminal 100 will be described with reference to FIG.

  The camera 120 drives a movable lens barrel 3 having a lens 4 to realize a shooting mode switching operation, an ISP (Image Signal Processor) 124 that processes an image signal obtained from the image sensor 104, and image data. A storage device 126 for storing images, a control logic unit 128, one or a plurality of memories 130 for temporarily storing images for electronic processing, a display means 132 for displaying optical images and electronically processed electronic images, An MPU (Micro Processing Unit) 134 is provided as a system controller for controlling these members.

  Here, the camera module 121 of the camera 120 is a signal of the image sensor unit 121a including the mechanical part of the lens driving device 1 including the movable lens barrel 3 having the lens 4 and the like, the image sensor 104, the driver 122, and the ISP 124. Consists of processing parts. The image sensor 104, the driver 122, and the ISP 124 are installed on a circuit board (not shown). The control unit includes a control logic unit 128 and an MPU 134. Further, the image acquisition unit includes the image sensor 104, the ISP 124, and a control unit. The MPU 134 serves as a switching command reading unit that reads a shooting mode switching command, an operation position confirmation unit that confirms the operation position of the lens 4, and a current position detection unit that detects the position of the lens 4, and a load detection that detects the load of the actuator. It also functions as a means.

  In the state shown in FIG. 3, when a predetermined changeover switch (not shown) is operated, a current flows through the coil 8. Then, a force acts on the magnet 6 according to Fleming's left-hand rule depending on the direction of the current and the direction of the magnetic field generated by the magnet 6. Note that Fleming's left-hand rule indicates the relationship between forces acting on an object that is carrying a line current when a line current flows in the magnetic field.

  In this example, since the coil 8 is fixed to the yoke 7 and the yoke 7 is fixed to the fixed holder 2, a force acts on the magnet 6 as a reaction. As a result, the movable lens barrel 3 on which the magnet 6 is fixed moves in the direction of the optical axis F while being restricted by the elastic force of the elastic member 9.

  When the upper surface of the movable barrel 3 moves to a predetermined height or hits the top surface component 30, the MPU 134 detects the load applied to the actuator, and appropriately supplies the current supplied to the coil 8 from the MPU 134 to the driver 122. A control signal is output so as to control to a proper value. The driver 122 controls the current supplied to the coil 8 to stop the movable lens barrel 3 and maintain a substantially vertical posture with respect to the optical axis of the lens 4. Since the technology for detecting the actuator load and controlling the operation of the actuator in accordance with the load is a well-known and commonly used technology, a detailed description thereof is omitted here.

  In the present embodiment, an example in which the lens driving device 1 is incorporated as a function of the camera portion of the camera-equipped mobile phone terminal 100 has been described. However, the lens driving device 1 includes a mobile computer, a PDA (Personal Digital Assistant), It can be used for other portable devices such as game machines, or incorporated into other camera devices such as surveillance cameras and medical cameras, and electronic devices such as automobiles and television receivers.

  In the above-described embodiment, the drive mechanism is configured by the magnet 6 and the coil 8. However, the magnet 6 is disposed at the position of the coil 8, and the coil 8 and the yoke 7 are disposed at the position of the magnet 6. Alternatively, so-called moving coil drive may be used.

  Further, the drive mechanism is not a magnetic circuit composed of the magnet 6, the yoke 7, and the coil 8, but may be another drive mechanism that generates a driving force such as a piezoelectric element type.

  Further, the present invention is not limited to each of the above-described embodiments. For example, the present invention is applied to a lens driving device in which two plate-like elastic bodies are arranged so as to be sandwiched from above and below the movable lens barrel. It goes without saying that various modifications and changes can be made without departing from the scope of the present invention.

1 is a top view of a lens driving device according to an embodiment of the present invention. It is a figure (AA sectional view taken on the line) which shows the lens drive device at the time of the focus operation | movement which concerns on one embodiment of this invention. It is a figure which shows the lens drive device which concerns on the other embodiment of this invention. It is a figure (BB sectional view) which shows the lens drive device at the time of the focus operation | movement which concerns on the other embodiment of this invention. 1 is a perspective view showing a camera-equipped mobile phone terminal according to an embodiment of the present invention. It is a figure which shows the block structural example of the mobile telephone terminal with a camera which concerns on one embodiment of this invention. It is a top view which shows the example of the conventional lens drive device (both sides drive). It is sectional drawing which follows the CC line of the lens drive device shown in FIG. It is a top view which shows the example of the conventional lens drive device (one side drive). FIG. 10 is a diagram (cross-sectional view along the line DD) showing a state before the focusing operation of the lens driving device shown in FIG. 9; It is the figure which showed the state at the time of the focus operation | movement of the lens drive device shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Lens drive device, 2 ... Fixed holder, 3 ... Movable lens barrel, 4 ... Lens, 5 ... Lens fixed cylindrical part, 6 ... Magnet, 7 ... Yoke, 8 ... Coil, 9 ... Elastic member, 9a-9d ... Fixed Part 10, hole 11, spring fixing range 12, elastic center, 13 gravity center, 14 thrust center, 15 weight, 30 top part, 100 mobile phone terminal with camera,

Claims (8)

A movable part that holds the lens and is movable in the optical axis direction of the lens;
A stationary part for accommodating the movable part;
A drive mechanism arranged asymmetrically with respect to the center of the lens and moving the movable part in the optical axis direction;
A plurality of elastic members each having one end and the other end connected to the movable part and the fixed part,
A lens driving device, wherein a thrust center of the driving mechanism is disposed within a range connecting the fixed portions of the movable portion and the plurality of elastic members on a plane substantially orthogonal to the optical axis. . 2. The lens driving device according to claim 1, wherein the driving mechanism is installed on an inner side of the movable portion in a plane substantially orthogonal to the optical axis. The lens driving device according to claim 2, wherein the movable portion has an asymmetric shape with respect to a center of the lens. A weight is provided on the movable part so that the center of weight of the movable part approaches or coincides with the center of elastic force of the elastic member and the center of thrust of the drive mechanism in a plane substantially perpendicular to the optical axis. The lens driving device according to claim 1. The lens driving device according to claim 1, wherein the elastic member is a leaf spring. The lens driving device according to claim 1, wherein the driving mechanism includes a magnetic circuit. The magnetic circuit is installed at a predetermined position of the movable part, and the fixed part is installed to face the first magnetic circuit part, and acts on the first magnetic circuit part to The movable part comprises a second magnetic circuit part that generates a driving force that moves in the optical axis direction,
The first magnetic circuit unit is a magnet, and the second magnetic circuit unit is a yoke and a coil;
The lens driving device according to claim 6, wherein the first magnetic circuit unit is a yoke and a coil, and the second magnetic circuit unit is a magnet. A mobile phone terminal with a camera equipped with a lens driving device,
The lens driving device includes:
A movable part that holds the lens and is movable in the optical axis direction of the lens;
A stationary part for accommodating the movable part;
A drive mechanism arranged asymmetrically with respect to the center of the lens and moving the movable part in the optical axis direction;
A plurality of elastic members each having one end and the other end connected to the movable part and the fixed part,
The camera-equipped mobile phone, wherein a thrust center of the drive mechanism is disposed within a range connecting the fixed portions of the movable portion and the plurality of elastic members on a plane substantially orthogonal to the optical axis. Phone terminal.

Images