JP4747732B2 - Lens driving device and mobile phone terminal with camera - Google Patents

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.

  By the way, 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 barrel 203 do not change from the lens center line, but the actuator is used for one-side driving. The thrust center 224 is biased and is positioned at the approximate center of the magnet 224 that is greatly deviated from the lens center.

  FIG. 11 shows a state during the focusing operation of the lens driving device shown in FIGS. For convenience of explanation, the positions of the elastic force center 212 and the gravity center 213 shown in FIG. 11 are slightly shifted from those shown in FIG. 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.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to correct the inclination of the lens with respect to the optical axis before and after the focusing operation in a lens driving device in which an actuator is arranged asymmetrically with respect to the center of the lens. And

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 drive mechanism for moving the movable part in the optical axis direction, and a one end and the other end of each elastic is connected to the fixed portion and the movable portion member, the locking member is provided in the vicinity of the drive mechanism moving parts, the elastic Since the center of elastic force of the member, the center of weight of the movable part, and the thrust center of the drive mechanism do not match, when the movable part rotates upwardly from the initial position along the optical axis, the locking member becomes the lens driving device. The movable part abuts on the upper top surface part, the movable part rotates about the contact part between the locking member and the top surface part as a fulcrum, and the movable part reaches the position where the upper surface part of the movable part and the top surface part collide in parallel. When moving, the movable part stops and the lens moves relative to the optical axis. A configuration in which the vertical position.
In the above configuration, preferably, the position where the locking member and the top surface component above the lens driving device abut on the plane orthogonal to the optical axis is the center of elastic force of the elastic member, the center of gravity of the movable portion, and the driving mechanism. The center of the lens is further away from the center of the thrust.

  According to the above configuration, since the drive mechanism is asymmetrically arranged with respect to the center of the lens, the contact portion between the locking member provided on the movable portion and the top surface component is provided when the movable portion does not translate. The tilt of the lens can be corrected by rotating the movable part as a fulcrum. Accordingly, it is possible to maintain an appropriate posture of the lens with respect to the optical axis at two positions before the focusing operation (initial position) and after the focusing operation.

  According to the present invention, the tilt of the lens can be corrected by rotating the movable portion with the contact portion between the locking member provided on the movable portion and the top surface component as a fulcrum. Therefore, it is possible to provide a lens driving device that maintains an appropriate posture with respect to the optical axis of the lens at two positions before the focusing operation (initial position) and after the focusing operation.

  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. Alternatively, a new space is created in the part where the parts are reduced, so that the degree of freedom in design is improved.

  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 be a small and thin mobile phone terminal with a camera.

  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. The optical axis refers to 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 be moved in the direction of the optical axis F. Is composed of a fixed holder 2, a yoke 7, and a coil 8, which are connected by four plate-like elastic members (plate springs) 9.

  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. In the lens driving device 1, since there is only one actuator, the thrust center 14 by the actuator is greatly deviated from the center of the movable lens barrel 3.

  One end of each elastic member 9 is fixed to a predetermined position of a fixing member 9 a formed of a substantially annular frame, and the other end is fixed to each of the four corners of the fixing holder 2. Then, the movable lens barrel 3 and the fixed holder 2 are connected by fitting and fixing the movable lens barrel 3 to the annular fixed member 9a.

  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 meanders in the same plane (XY plane). It is formed in the shape.

  In addition, at a part of the outer wall (cylindrical surface) of the movable lens barrel 3, one or more locking members that the movable lens barrel 3 abuts against a top surface component disposed above the lens driving device 1 described later during the focusing operation. 10 is provided. In the example of FIG. 1, two locking members 10 are provided in the vicinity of the actuator and at positions symmetrical with respect to the X axis passing through the center of the lens 4. Protruding portions 11 that abut are provided. The convex portion 11 is provided at a position farther from the lens center than the thrust center 14 of the actuator.

  FIG. 2 is a cross-sectional view taken along line AA of the lens driving device 1 shown in FIG. 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. Each elastic member 9 is arranged in one plane at an initial position before the focusing operation. Here, “in one plane” means a plane that is substantially perpendicular to the optical axis and has the same height from the bottom of the fixed holder 2.

  The movable lens barrel 3 is composed of a resin-made lens fixing cylinder 5, and a substantially disk-shaped flange 5 a is formed along the outer periphery on the same plane at the lower part of the cylindrical surface of the lens fixing cylinder 5. . A magnet 6 is placed and fixed on the flange 5a. Inside the lens fixing cylinder 5, the 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 cylinder 5, and the intermediate member 28. You may be comprised integrally by 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 in FIG. 2) of the lens fixing cylinder 5 to take the reflected light from the subject into the lens fixing cylinder 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 includes a coil 8 provided on the lens center side of the yoke 7 provided on one of the peripheral walls of the fixed holder 2, and the lens fixing cylinder 5. And a magnet 6 that is an electromagnetic member that generates an electromagnetic attractive force or an electromagnetic repulsive force between the coil 8 and the coil 8. The magnet 6 is disposed so as to face the coil 8 positioned on the lens center side of the yoke 7 and constitutes a magnetic circuit in the lens driving mechanism.

  The actuator is provided in one direction on the XY plane perpendicular to the optical axis F in the space between the fixed holder 2 and the movable lens barrel 3. 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.

  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, the elastic force center 12 of the elastic member 9 and the weight center 13 of the movable barrel 3 are located substantially at the center of the lens, and the thrust center 14 of the actuator is located substantially at the center of the magnet 14 for one-side driving. Since they are located, the positions of the three centers do not match. Therefore, the movable lens barrel 3 cannot perform an ideal translational motion. However, in this example, by providing the locking member 10 in the movable lens barrel 3, the movable lens barrel 3 can be moved in the direction of the optical axis F as a result.

  Hereinafter, the behavior of the lens driving device 1 during the focusing operation will be described. FIG. 3 shows the state of the lens driving device 1 during the focusing operation. For convenience of explanation, the positions of the elastic force center 12 and the gravity center 13 shown in FIG. 3 are slightly shifted from those shown in FIG.

  When the current is supplied to the coil 8 and the actuator is driven from the state before the focusing operation shown in FIG. 2, the magnet 6 moves upward by the action of electromagnetic force, so that the magnet 6 side of the movable barrel 3 (in the drawing) (Right side) is lifted upwards. At this time, an elastic force moment is generated at the elastic force center 12 of the elastic member 9, a gravity moment is generated at the weight center 13 of the movable barrel 3, and a thrust moment is generated at the thrust center 14 of the actuator, which is not a translational motion in the direction of the optical axis F. Then, a rotational movement (counterclockwise in the drawing) is performed around the contact portion between the movable barrel 3 and the bottom of the fixed holder 2.

  When the movable lens barrel 3 is lifted to a certain height, the convex portion 11 of the locking member 10 provided in the vicinity of the magnet 6 of the movable lens barrel 3 is in a state where the optical axis F and the top surface component 30 are not perpendicular ( It strikes against the top surface component 10 with a lens tilt θ1).

  Here, a current is further passed through the coil 8, and the thrust moment Mf1 generated at the thrust center 14 is changed to the elastic force moment Mk1 generated by the elastic force k acting on the elastic force center 12 and the gravity g acting on the weight center 13 of the movable barrel 3. When the total of the gravitational moment Mg1 generated by the above is exceeded, a rotational motion (clockwise in the drawing) is started with the convex portion 11 and the contact portion 15 of the top surface component 30 as a fulcrum.

  The movable barrel 3 rotates clockwise around the contact portion 15 and moves to a position where the upper surface of the movable barrel 3 abuts against the top surface component 30 and is parallel to the top surface component 30 as shown in FIG. . When the upper surface of the movable lens barrel 3 moves until it hits the top surface component 30 in parallel, the movement of the movable lens barrel 3 is stopped.

  By controlling the movement of the cylindrical lens barrel 3 by the locking member 10 as described above, the lens inclination of the movable lens barrel 3 is corrected, and the upper surface of the movable lens barrel 3 hits the top surface component 30 substantially in parallel. Sometimes, the lens 4 is in a posture substantially perpendicular to the optical axis F.

  According to the lens driving device 1 having the above-described configuration, the lens 4 is held before and after the focusing operation (initial position) by correcting the inclination of the movable barrel 3 using the locking member 10. The movable lens barrel 3 can be moved in the direction of the optical axis F. As a result, an appropriate posture with respect to the optical axis of the lens 4 can be maintained at two positions, that is, an initial position before movement and a position moved to a predetermined height. Therefore, it is possible to prevent deterioration of optical characteristics (resolution) when the movable lens barrel 3 is focused to a predetermined height.

  Further, by reducing the number of parts and using only one actuator (one-side drive), the actuator is asymmetrically arranged with respect to the lens center, and the elastic force center 12 of the elastic member 9 and the movable lens barrel 3 The positional relationship between the weight center 13 and the thrust center 14 of the actuator is lost, and the movable lens barrel 3 does not move in translation. However, by providing the movable lens barrel 3 with the locking member 10, the movable lens barrel 3 is moved to the initial position and the predetermined height. At the two positions, the lens 4 can be maintained in an appropriate posture with respect to the optical axis.

  Therefore, since the problem caused by the component reduction is solved, the actuator can be asymmetrically arranged and the components can be reduced, and the thickness and size can be reduced as compared with the lens driving device described in Patent Document 1. become.

  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.

  As can be easily understood from FIG. 4, the convex portion 11 provided on the locking member 10 is formed on the movable lens barrel 3 when the upper surface of the movable lens barrel 3 collides with the top surface component 30. It is formed lower than the upper surface of the movable lens barrel 3 so as not to protrude above the upper surface. In addition, as described above, in order for the movable lens barrel 3 to rotate about the abutment portion 15 of the convex portion 11 and the top surface component 30 as a fulcrum, from the elastic force center 12, the weight center 13, and the thrust center 14. However, it is important to provide the convex portion 11 at a position further from the lens center.

  Next, an example in which the lens driving device 1 described above is mounted on a portable 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 cylinder 5 faces the subject side. 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.

  In general, the functions of a camera mounted on a mobile device such as a mobile phone terminal are not so high in performance due to cost and design space problems. For example, it is possible to switch between two shooting modes such as normal shooting, fixed magnification zoom shooting, and macro shooting. The cellular phone terminal 100 equipped with the lens driving device 1 described above can be switched in a state in which the posture of the lens is appropriately maintained between the initial position and the predetermined position of the movable barrel 3 while reducing the size and cost. In addition, the lens driving device according to the present invention is particularly effective for a mobile phone terminal or the like that is sufficient if a low-function camera is mounted.

  Note that the mobile phone terminal to which the lens driving device 1 is applied is not limited to this example. For example, the display unit and the operation unit may be an integrated mobile phone terminal.

  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 cylindrical lens barrel 3 moves to a predetermined height and the locking member 10 of the cylindrical lens barrel 3 comes into contact with the top surface component 30, the MPU 134 detects the load applied to the actuator, and the MPU 134 detects the load on the driver 122. A control signal for increasing the current supplied to the coil 8 is output. The driver 122 increases the current supplied to the coil 8, the movable lens barrel 3 rotates with the contact portion 15 of the convex portion 11 and the top surface component 30 as a fulcrum, and the upper surface of the movable lens barrel 3 becomes the top surface component 30. The movable barrel 3 is moved until it hits. A technique for detecting the load of the actuator and controlling the operation of the actuator in accordance with the load is a well-known and commonly used technique, and thus detailed description thereof is omitted here.

  When the upper surface of the movable barrel 3 hits the top surface component 30, the MPU 134 detects a load applied to the actuator, and sends a control signal to the MPU 134 to the driver 122 to control the current supplied to the coil 8 to an appropriate value. Output. The driver 122 controls the current supplied to the coil 8, stops the movable barrel 3 with the upper surface of the movable barrel 3 abutting in parallel with the top surface component 30, and is substantially perpendicular to the optical axis of the lens 4. To maintain.

  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.

  Furthermore, the present invention is not limited to the above-described embodiments, and 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) which shows the lens drive device before the focus operation | movement which concerns on the example of 1 embodiment of this invention. It is a figure which shows the lens drive device at the time of the focus operation | movement which concerns on the example of 1 embodiment of this invention. It is a figure which shows the lens drive device after the focus operation | movement which concerns on the example of 1 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 BB 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 (a cross-sectional view taken along the line CC) illustrating a state before the focusing operation of the lens driving device illustrated 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 cylinder, 6 ... Magnet, 7 ... Yoke, 8 ... Coil, 9 ... Elastic member, 10 ... Locking member, DESCRIPTION OF SYMBOLS 11 ... Convex part, 12 ... Elastic force center, 13 ... Gravity center of gravity, 14 ... Thrust center, 15 ... Contact part, 30 ... Top surface component, 100 ... Mobile phone terminal with a camera, Mk1 ... Elastic force moment, Mg1 ... Gravity Moment, Mf1 ... Thrust moment

Claims (9)

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;
One end and the other end each include an elastic member connected to the movable part and the fixed part,
A locking member is provided in the vicinity of the drive mechanism of the movable part, and the center of elastic force of the elastic member, the center of weight of the movable part, and the thrust center of the drive mechanism do not match, so that the movable part is in the initial position. When the rotary member rotates upward along the optical axis, the locking member comes into contact with the top surface component above the lens driving device, and the movable portion comes into contact with the locking member and the top surface component. , And the movable part stops when the movable part moves to a position where the upper surface of the movable part and the top surface component abut against each other in parallel. Lens drive device with a vertical posture . The position where the locking member and the top surface component above the lens driving device are in contact with each other on the plane perpendicular to the optical axis is the elastic force center of the elastic member, the weight center of gravity of the movable portion, and the driving mechanism. the lens driving device according to claim 1 that away from the lens center than the thrust center. The locking members are located at two positions on the outer wall of the movable part across the drive mechanism on a plane orthogonal to the optical axis, and the contact positions of the respective locking members with the top surface component are the lenses. the lens driving device according to claim 2 that is provided so as to be substantially equidistant from the center. The drive mechanism is a lens driving device according to claim 1 that consists of 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;
Alternatively, the first magnetic circuit yoke and the coil, the second magnetic circuit portion is a lens driving device according to claim 4 Ru magnet der. When the locking member and the top surface component above the lens driving device are in contact, the thrust moment generated at the center of thrust of the movable portion is the elastic moment generated at the center of elastic force of the elastic member and the center of weight of the movable portion. the lens driving device according to claim 5, current Ru is supplied to the coil so as to exceed the sum of the gravitational moment which occurs. The elastic member is a leaf spring disposed substantially symmetrically with respect to the center of the lens.
The lens driving device according to claim 1. 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;
One end and the other end each include an elastic member connected to the movable part and the fixed part,
A locking member is provided in the vicinity of the drive mechanism of the movable part, and the center of elastic force of the elastic member, the center of weight of the movable part, and the thrust center of the drive mechanism do not match, so that the movable part is in the initial position. When the rotary member rotates upward along the optical axis, the locking member comes into contact with the top surface component above the lens driving device, and the movable portion comes into contact with the locking member and the top surface component. , And the movable part stops when the movable part moves to a position where the upper surface of the movable part and the top surface component abut against each other in parallel. Become vertical
Mobile phone with camera. The position where the locking member and the top surface component above the lens driving device are in contact with each other on the plane perpendicular to the optical axis is the elastic force center of the elastic member, the center of gravity of the movable portion, and the thrust of the driving mechanism. It is farther from the center of the lens than the center
The mobile phone terminal with a camera according to claim 8.

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