JP4802605B2 - Lens driving device and camera-equipped mobile phone - Google Patents

Description

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

  For example, a camera-equipped mobile phone is known as a camera-equipped mobile device using a lens driving device. In such a camera-equipped mobile phone, a movable barrel containing a lens with an elastic member is suspended from a fixed holder, and a propulsive force is generated by energizing a coil of a magnetic circuit that constitutes a drive mechanism from the outside. A technique of moving a lens barrel in the optical axis direction is known (see, for example, Patent Document 1).

  In general, in order to obtain an appropriate camera focus sensitivity, it is important to balance the thrust constant of the force generated by the magnetic circuit and the spring constant of the elastic member that suppresses the force constant. In other words, if the thrust constant of the magnetic circuit is high, the spring constant is increased, that is, the spring is hardened to balance, and if the magnetic circuit thrust constant is low, the spring constant is lowered, that is, the spring is softened to balance. It is necessary to take.

  As a method for reducing the spring constant, it is conceivable to reduce the cross-sectional area of the spring of the elastic member. However, a spring having a cross-sectional area equal to or less than a predetermined thickness has hardly been used, and there is a problem that it is difficult to mold such a spring with a mold.

  As another method for lowering the spring constant, it is conceivable to change the spring material to a soft material having a low elastic modulus. However, a soft material having a lower elastic modulus than a copper material that is generally used as a spring material is very expensive, and it is not practical to use it in terms of cost.

  Therefore, as a method for lowering the spring constant, it is known to use an elastic member having a meandering shape and lengthen the effective length of the spring.

JP 2004-333955 A

  As a lens driving device, for example, in the case of a linear driving method employing a moving coil method, as shown in FIG. 6, a magnet yoke 115 constituting a part of a point-symmetrical magnetic circuit fixed to a fixed holder 120. On the other hand, a coil existing inside the movable lens barrel 110 and the yoke 115 is suspended on a fixed holder via an elastic member 119 having a meandering shape, and the coil is energized from the outside through the elastic member 119, thereby moving the lens barrel. A method of driving 110 in the optical axis direction is conceivable.

  However, such a lens driving device 101 requires a space in the fixed holder 120 for arranging a point-symmetrical magnetic circuit and an elastic member extending outward in a plane direction perpendicular to the optical axis direction. As a result, it is difficult to reduce the size of the lens driving device.

  In consideration of the above-described points, the present invention provides a lens driving device and a camera-equipped mobile phone that can be miniaturized with high focus sensitivity.

  A lens driving device according to the present invention includes a movable lens barrel having a lens, a drive mechanism that moves the movable lens barrel in the optical axis direction of the lens, and a rectangular shape that houses the movable lens barrel and the drive mechanism. A lens comprising: a fixed holder; and an elastic member having a meandering shape formed by a straight portion and a curved portion, which connects the movable barrel and the fixed holder and holds the movable barrel movably. In the driving device, the driving mechanism includes a magnetic circuit including a coil, a yoke, and a magnet, and the magnetic circuit is disposed in parallel with one opposite two sides of the fixed holder. The configuration.

  In addition, the linear portion of the elastic member of the lens driving device according to the present invention is arranged in parallel with the two opposite sides of the fixed holder.

  Preferably, the elastic member of the lens driving device according to the present invention is arranged in the same plane of the fixed holder.

  In the lens driving device of the present invention, the members constituting the magnetic circuit are arranged in parallel to each other, so that the lens driving device can be reduced in size.

  The camera-equipped mobile phone according to the present invention is a camera-equipped mobile phone having a lens driving device and display means for displaying an image obtained by the lens driving device, and the lens driving device holds a lens. A movable barrel, a drive mechanism for moving the movable barrel in the optical axis direction of the lens, a rectangular fixed holder for housing the movable barrel and the drive mechanism, the movable barrel and the fixed holder An elastic member having a meandering shape formed by a straight portion and a curved portion, and movably holding the movable barrel, wherein the drive mechanism includes a coil And a magnetic circuit composed of a yoke and a magnet, and the magnetic circuit is arranged in parallel with two opposing sides of the fixed holder.

  In the camera-equipped mobile phone of the present invention, since the lens driving device is downsized, the camera-equipped mobile phone using the lens driving device can be downsized.

  The lens driving device according to the present invention can be a small lens driving device.

  The camera-equipped mobile phone according to the present invention can be a small camera-equipped mobile phone.

  Hereinafter, examples of the best mode for carrying out a lens driving device and a camera-equipped mobile phone according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the following examples.

FIG. 1 is a plan view of a lens driving device according to an embodiment of the present invention.
As shown in FIG. 1, a lens driving device 1 according to this example includes a movable lens barrel 10 having a lens 12, a driving mechanism having a driving coil 14, a yoke 15, and a driving magnet 18, and an elastic member. 19 and a fixed holder 20.

  The movable lens barrel 10 has a bottomed cylindrical shape, and includes a cylindrical portion 10a for holding the lens and a bottom portion 10b having an emission hole 36 for emitting light from the lens 12. . A plurality of lenses 12 are arranged inside the movable lens barrel 10.

  A flat part 11 for attaching a flat magnet 18 is formed on a part of the outer periphery of the cylindrical part 10a. Two cylindrical portions 11 are formed in the cylindrical portion 10 a so as to be arranged at symmetrical positions with the lens 12 as the center.

  The flat magnet 18 is fixed to the flat portion 11 of the cylindrical portion 10a with an adhesive. That is, the movable lens barrel 10 is magnetized with a two-pole magnet 18 having a flat plate shape.

  The fixed holder 20 is formed in a quadrangular shape having four corners. Specifically, the fixed holder 20 includes a substantially square bottom portion and a peripheral wall portion along the bottom portion. The coil 14, the yoke 15, the magnet 18, and the elastic member 19 are accommodated.

  A notch 20a is formed on the inner periphery of the peripheral wall of the fixed holder 20 at a position facing the flat magnet 18 fixed to the movable lens barrel 10, and the notch 20a has a flat plate shape. The yoke 15 formed in the above is fixed by an adhesive.

  A flat coil 14 is fixed to the yoke 15 fixed to the fixed holder 20 with an adhesive so as to face the flat magnet 18 fixed to the movable lens barrel 10.

  That is, in the lens driving device 1 of this example, the magnet 18, the coil 14, and the yoke 15 arranged in parallel in one direction constitute a magnetic circuit that constitutes a part of the driving mechanism. Specifically, two sets of yokes 15, coils 14, and magnets 18 are arranged so as to be parallel to one set of sides of the two sets of opposing sides of the fixed holder 20. In this example, two sets of yokes 15, coils 14, and magnets 18 constituting the magnetic circuit are arranged at symmetrical positions around the lens 12, but one set of yokes 15 is arranged at one position of the lens. The coil 14 and the magnet 15 may be arranged.

  Between the outer periphery of the cylindrical portion 10a of the movable lens barrel 10 and the inner periphery of the fixed holder 20, two elastic members 19 that hold the movable lens barrel 10 movably in the optical axis direction are disposed. . These elastic members 19 are arranged at symmetrical positions with the lens 12 in between.

FIG. 2 is a plan view of an elastic member used in the lens driving device according to the embodiment of the present invention.
As shown in FIG. 2, the elastic member 19 includes an arcuate fixing portion 19c formed so as to match the outer peripheral shape of the cylindrical portion 10a in order to be coupled to the movable cylinder 10, and a plurality of extending portions extending from the fixing portion 19c. It consists of an arm portion 19A. The arm portion 19A has a meandering shape and is composed of a plurality of linear portions 19a and curved portions 19b. The plurality of linear portions 19a of the arm portion 19A are configured to be parallel to each other. In addition, a fixing portion 19d for coupling to the fixing holder 20 is formed at the tip of the arm portion 19A.

  If necessary, increasing the thickness of the elastic member 19 increases the spring constant of the elastic member, thereby stabilizing the movement of the movable lens barrel 10 without changing the resonance frequency of the movable lens barrel 10 so much. Can be made.

The arrangement of the elastic member 19 in the fixed holder 20 will be described again using FIG.
The elastic member fixing portion 19c is fixed to the portion of the outer periphery of the cylindrical portion 10a other than the magnet 18 by an adhesive or the like. Further, the fixing portion 19 d of the elastic member is fixed near the corner of the fixing holder 20 with an adhesive. In this way, the two elastic members 19 are arranged in the fixed holder 20 so as to be symmetric with respect to the lens 12.

  That is, the arm portion 19 </ b> A of the elastic member is arranged in a space formed between the cylindrical portion 10 in the fixed holder 20 and the fixed holder 20. Further, the linear portion 19 a of the arm portion 19 </ b> A is disposed so as to be parallel to the opposing sides other than the side to which the yoke 15 is fixed among the two opposing sides of the fixing holder 20. .

  As described above, according to the lens driving device 1 of the present example, the magnet 18, the yoke 15, and the coil 14 constituting the magnetic circuit are arranged so as to be parallel to a pair of opposite sides of the fixed holder 20. The space for arranging the magnetic circuit in the fixed holder 20 can be reduced, and the lens driving device 1 can be reduced in size. Furthermore, according to the lens driving device 1 of the present example, the linear portion 19a of the elastic member 19 is arranged so as to be parallel to another set of opposite sides of the fixed holder 20, The arrangement space of the elastic member 19 can be reduced, and the lens driving device 1 can be reduced in size.

FIG. 3 is a cross-sectional view of the lens driving device according to the embodiment of the present invention taken along line AA ′ shown in FIG.
As shown in FIG. 3, the lens driving device 1 mainly includes a movable lens barrel 10 that moves along the optical axis direction F of the lens 12 indicated by an arrow in the drawing, and a drive that moves the movable lens barrel 10. The coil 14, the yoke 15, and the magnet 18 that constitute the magnetic circuit that constitutes the mechanism, and the fixed holder 20 that accommodates these members.

  Inside the movable lens barrel 10, a lens 12 held by a cylindrical portion 10a and an intermediate member 28 as a spacer are arranged.

  The lens 12 is a photographing lens of a camera and is configured by combining a plurality of lens members. The upper side of FIG. 3 is the subject side lens member 12a, and the lower side is the body side lens member 12b. In the lens driving device 1 of the present example, the movable lens barrel 10 is composed of a plurality of members such as the lens 12, the resin lens barrel portion 10a, and the intermediate member 28. All members may be configured integrally with the same member.

  The subject-side lens member 12a has a circular 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 is in contact with the intermediate member 28. The camera body side lens member 12b has a 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. Further, the holder portion of the body side lens member 12 b is also in contact with the intermediate member 28.

  The lens portions of the subject side lens member 12a and the body side lens member 12b are resin aspheric lenses, and the holder portion and the lens portion are formed by integral molding of resin.

  The intermediate member 28 is a disk-shaped member having a hole 34 in the center. The intermediate member 28 keeps the distance between the subject side lens member 12a and the body side lens member 12b constant.

  Although the cylindrical portion 10a of the movable lens barrel 10 has a bottomed cylindrical shape, a circular incident window 36 for taking reflected light from the subject into the lens 12 is formed at the center of the bottom portion 10b. Further, below the entrance window 36, the subject side lens 12a, the intermediate member 28, and the body side lens 12b are arranged in order.

  The drive coil 14 attached to the yoke 15 in the fixed holder 20 and the drive attached to the cylindrical portion 10a that is an electromagnetic member that generates an electromagnetic attractive force or an electromagnetic repulsive force between the drive coil 14. The magnets 18 for use are disposed in the fixed holder 20 so as to face each other at substantially the same height.

  As is apparent from FIG. 3, the elastic member 19 is disposed in the same plane in the fixed holder 20. Here, the term “in one plane” means a surface having the same height in the fixed holder 20. Further, the elastic member 19 is arranged in a plane passing through the position of the center of gravity g of the movable lens barrel 10. That is, the movable lens barrel 10 is suspended from the fixed holder 20 by the elastic member 19 at the center of gravity position g.

  Note that an imaging element unit (not shown) having a filter, an imaging element, and the like is disposed on the rear side of the lens driving device 1 along the optical axis direction F.

  As described above, according to the lens driving device 1 of this example, the elastic member 19 is disposed near the center of gravity g of the movable lens barrel 10 and the movable lens barrel 10 is suspended from the fixed holder 20 at the center of gravity position g. Even when the camera function is used in a stable posture, the movable member 10 is inclined with respect to the optical axis direction F of the lens because the elastic member 19 holds the center of gravity g of the movable lens barrel 10. Can be prevented. As a result, even when the camera function is used in an unstable posture, the movable lens barrel 10 does not tilt from the optical axis direction, thereby preventing deterioration of optical performance such as the resolution of the camera function. Can do.

  Furthermore, according to the lens driving device 1 of this example, since the movable barrel 10 is held by the elastic member 19 arranged on the same plane, a plurality of elastic members are arranged at different heights in the fixed holder 20. Therefore, the lens driving device 1 can be made small and thin.

  As shown in FIG. 3, in the lens driving device 1 of the present example, the yoke 15 fixed to the fixed holder 20, the coil 14, and the end surface formed on the magnet 18 have substantially the same height. A surface is formed. The bottom 10 b of the movable lens barrel 10 is held by the elastic member 19 in a state of protruding from the surface formed by the yoke 15, the coil 14, and the upper end surface of the magnet 18. That is, a step is formed between the upper part of the yoke 15 and the bottom 10b of the movable lens barrel 10, and a space S as shown by a broken line in the figure is formed in the step part.

  Thus, according to the lens driving device 1 of the present example, the space S is formed above the yoke 15 and the magnet 18, so that the lens driving device 1 can be made smaller by the space, The lens driving device 1 can be made small and thin.

  Next, an example in which the lens driving device 1 described above is mounted on a portable device will be described.

  FIG. 4 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. 4, the camera-equipped mobile phone terminal 50 includes a lower housing 51 in which operation buttons (operation units) are arranged, and an upper housing 52 in which a portion for displaying an image taken by the camera is formed on the back surface. It consists of. By sliding or folding the upper housing 52 so as to match the lower housing 51, a compact size convenient for carrying can be achieved. When shooting using the camera function, as shown in FIG. 4, the lower casing 51 and the upper casing 52 are used in a shifted state.

  A hole 52a for embedding the lens driving device 1 is formed in the back surface of the upper casing 52 of the camera-equipped mobile phone terminal 50. The lens driving device 1 is attached to the hole 52a so that the entrance window 36 formed on the bottom 10b of the movable barrel 10 faces the subject. After the lens driving device 1 is attached, the lens driving device 1 is installed from the upper surface so as to cover, for example, a transparent resin top surface component (not shown).

  According to the camera-equipped mobile phone terminal 50 of this example, since the thin and small lens driving device 1 is used, the thickness of the upper housing 52 can be reduced. As a result, when the lower casing 51 and the upper casing 52 are matched, the overall thickness of the camera-equipped mobile phone terminal can be reduced, so that the camera-equipped mobile phone terminal 50 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 50 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 at the initial position and the predetermined position of the movable barrel 10 while reducing the size and reducing the 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 50 will be described with reference to FIG.

  A camera 120 drives a movable lens barrel 10 having a lens 12 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 of the camera 120 is a signal processing portion of an image sensor unit including a mechanical part of the lens driving device 1 including a movable lens barrel 10 having a lens 12, an image sensor 104, a driver 122, and an ISP 124. Consists of 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 12, and a current position detection unit that detects the position of the lens 12, and a load detection that detects the load of the actuator. It also functions as a means.

  Here, when a predetermined changeover switch (not shown) is operated in the state of the lens driving device 1 shown in FIG. 3, a current flows through the driving coil 14 via the elastic member 19. Then, a reaction force acts on the driving magnet 18 fixed to the movable lens barrel 10 according to Fleming's left-hand rule depending on the direction of the current flowing in the coil 14 and the direction of the magnetic field generated by the driving magnet 18. Thereby, the movable lens barrel 10 moves in the optical axis direction F by the elastic force of the elastic member 19. 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 the above-described embodiment, a so-called moving magnet system in which a drive mechanism is configured by the magnet 18 fixed to the movable lens barrel 10 and the coil 14 fixed to the fixed holder 20 is employed. A so-called moving coil drive system may be employed in which the coil is disposed at the position of the magnet. In this case, the coil is fixed to the movable lens barrel and the magnet is fixed to the yoke 15. A force acts on the coil according to Fleming's left-hand rule, and the movable lens barrel 10 moves in the optical axis direction.

  When the cylindrical lens barrel 10 moves to a predetermined height and the locking member provided on the cylindrical lens barrel 10 comes into contact with the top surface component provided on the camera 50, the MPU 134 loads the actuator. It detects and outputs a control signal for increasing the current supplied to the coil 14 from the MPU 134 to the driver 122. The driver 122 increases the current supplied to the coil 14 and moves the movable lens barrel 10 until the upper surface of the movable lens barrel 10 hits the top surface component. 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 lens barrel 10 hits the top surface component, the MPU 134 detects the load applied to the actuator, and outputs a control signal from the MPU 134 to the driver 122 so as to control the current supplied to the coil 14 to an appropriate value. To do. The driver 122 controls the current supplied to the coil 14, stops the movable lens barrel 10 in a state where the upper surface of the movable lens barrel 10 is in contact with the top surface component, and takes a substantially vertical posture with respect to the optical axis of the lens 12. 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 50 is shown. 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.

  Further, the drive mechanism is not a magnetic circuit composed of the magnet 18, the yoke 15, and the coil 14, 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.

FIG. 1 is a plan view of a lens driving device according to an embodiment of the present invention. FIG. 2 is a plan view of an elastic member used in the lens driving device according to the embodiment of the present invention. FIG. 3 is a sectional view of the lens driving device according to the embodiment of the present invention. FIG. 4 is a perspective view of the camera-equipped mobile phone when the lens driving device according to the present invention is attached. FIG. 5 is a schematic diagram showing a system configuration of a camera including the lens driving device according to the embodiment of the present invention. FIG. 6 is a plan view of a conventional lens driving device.

Explanation of symbols

1 .... Lens driving device, 10 .... Moving barrel, 12 .... Lens, 14 .... Coil for driving, 15 .... Yoke, 18 .... Magnet for driving, 19 .... Elastic member, 20 .... Fixed holder, 28..Intermediate member, 34..hole, 36..incident window, 50..mobile phone with camera, F..optical axis direction, S..space, g..center of gravity of movable barrel

Claims (2)

A movable lens barrel having a lens;
A drive mechanism for moving the movable lens barrel in the optical axis direction of the lens;
A rectangular fixed holder that houses the movable barrel and the drive mechanism;
A plurality of elastic members having meandering shapes formed by linear portions and curved portions that connect the movable barrel and the fixed holder and hold the movable barrel movably;
The drive mechanism includes a flat plate magnet fixed to the movable barrel, and a yoke fixed to the fixed holder so as to face the flat plate coil, and a flat plate coil is fixed to the magnet. Have a circuit,
This magnetic circuit is arranged in parallel with one opposite two sides of the fixed holder,
The straight portion of the elastic member is arranged in parallel with the other two opposite sides of the fixed holder, and the plurality of elastic members are on the same plane of the fixed holder passing through the center of gravity of the movable lens barrel. A lens driving device, wherein the lens driving device is disposed inside. A camera-equipped mobile phone having a lens driving device and display means for displaying an image obtained by the lens driving device,
The lens driving device includes:
A movable lens barrel having a lens;
A drive mechanism for moving the movable lens barrel in the optical axis direction of the lens;
A rectangular fixed holder that houses the movable barrel and the drive mechanism;
A plurality of elastic members having meandering shapes formed by linear portions and curved portions that connect the movable barrel and the fixed holder and hold the movable barrel movably;
The drive mechanism includes a flat plate magnet fixed to the movable barrel, and a yoke fixed to the fixed holder so as to face the flat plate coil, and a flat plate coil is fixed to the magnet. Have a circuit,
This magnetic circuit is arranged in parallel with one opposite two sides of the fixed holder,
The straight portion of the elastic member is arranged in parallel with the other two opposite sides of the fixed holder, and the plurality of elastic members are on the same plane of the fixed holder passing through the center of gravity of the movable lens barrel. A mobile phone with a camera, characterized in that it is arranged inside.

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