JP4811724B2 - Lens drive device - Google Patents

Description

  The present invention relates to a lens driving device that is mounted on a small camera and drives a lens in an optical axis direction.

  In Patent Document 1, a lens support is supported by a spring with respect to a casing, and power is supplied to a coil body provided on the lens support, whereby electromagnetic force against a magnetic field formed by a magnet and a yoke fixed to the casing is obtained. It is disclosed that the lens support is driven to hold the lens support in a predetermined position by balancing the electromagnetic force and the biasing force of the spring.

  In Patent Document 1, the yoke is formed in an annular shape with a U-shaped cross section, and a magnet and a coil fixed to the outer periphery of the lens support are arranged in the U-shape of the yoke. That is, the lens driving device of Patent Document 1 is configured to surround the magnet and the coil with the outer peripheral side wall and the inner peripheral side wall of the yoke.

JP 2006-58662 A

  Incidentally, there is a strong demand for further downsizing of the lens driving device. However, in the conventional lens driving device, the yoke has an annular shape with a U-shaped cross section, and magnets and coils are arranged between the inner peripheral wall and the outer peripheral side wall of the yoke, so that the radial dimension (perpendicular to the optical axis of the lens) There was a limit to downsizing the dimensions in the direction of

  In addition, since magnets and coils are disposed inside the U-shaped yoke, there is a problem that the assembly workability is poor.

  Accordingly, an object of the present invention is to provide a lens driving device that is small in size and excellent in assembling workability.

The invention according to claim 1 is a cylindrical lens support that holds a lens, a coil body that is fixed to the outer periphery of the lens support, and a plurality of magnet portions that are provided on the outer periphery of the coil body and are arranged facing the coil body. And a yoke provided on the outer periphery of the plurality of magnet portions, a housing that holds the yoke and the magnet portions, and a spring that supports the lens supporter so as to be movable in the optical axis direction of the lens with respect to the housing, In a lens driving device that drives a lens support in the direction of the optical axis of a lens by electromagnetic force generated by feeding power to a coil body, each magnet portion is polarized in the radial direction into an N pole and an S pole and the optical axis of the lens A plurality of magnetic poles having different directions are provided, the yoke has a rectangular tube shape, each magnet portion is disposed on the inner peripheral side of each corner portion of the rectangular tube, and the coil body is arranged in the optical axis direction of the magnet portion. optical axis direction in correspondence with the magnetic poles Plurality is provided with, the coil body adjacent and wherein the flowing reverse current one another.

  According to the first aspect of the present invention, since a magnetic field is generated between the adjacent magnetic poles by the magnetic field lines from the N pole to the S pole (see FIG. 3), the coil body facing the N pole of the magnet section. When a current in a different direction is passed through the coil body facing the S pole, an electromagnetic force (thrust) in the same direction acts on the optical axis direction of the lens, and the lens support is formed by the resultant force of the plurality of electromagnetic forces. Drive.

  In addition, since the yoke is arranged only on the outer peripheral side of the magnet, the magnetic field strength acting on one coil body is smaller than when the yoke is arranged at a position sandwiching (enclosing) the magnet. By providing the body, the lens support is driven by the resultant force of the electromagnetic force generated in each coil body, so that sufficient thrust can be obtained.

  Since the yoke is arranged only on the outer peripheral side (one side) of the magnet and can be made into a single plate, there is no need to provide a width with a U-shaped cross-section like in the past, so the radial direction The dimension in can be made smaller than before.

  The yoke, the magnet, and the coil body need only be sequentially arranged in the radial direction of the lens support body, and it is not necessary to incorporate the magnet and the coil body in the U-shaped yoke as in the prior art, and the assembly is easy.

  By arranging the magnet part at the corner of the square tube-shaped yoke, it is not necessary to arrange the magnet part on the side part of the square tube, and at least the thickness of the magnet part in the dimension between the side surface of the yoke and the lens support Can be made smaller. Moreover, the thickness of the magnet part in a corner | angular part can be thickened, and the magnetic field intensity of the magnet part in a corner | angular part can be raised.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. First, the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an exploded perspective view of the lens driving device according to the first embodiment, FIG. 2 is a longitudinal sectional view of the lens driving device according to the first embodiment, and FIG. 3 is according to the first embodiment. FIG. 3 is an enlarged cross-sectional view showing a portion A shown in FIG. 2 in order to explain the operation of the lens driving device. In FIG. 1, the lens 3 shown in FIG. 2 is omitted.

  The lens driving device 1 according to the first embodiment is a lens driving device for a small autofocus camera incorporated in a mobile phone.

  The lens driving device 1 includes a housing 2 (see FIG. 2). In the housing 2, a lens support 5 that holds a lens 3 (see FIG. 2), coil bodies 7a and 7b, and a magnet unit 9 are provided. And a yoke 11, a light receiving side (front side) spring 13, and an image forming side (rear side) spring 14.

  The housing 2 includes a frame 15 provided on the light receiving side of the lens and a base 17 provided on the imaging side.

  A yoke 11 is disposed between the frame 15 and the base 17. The yoke 11 has a rectangular tube shape, and each corner 12 is chamfered.

  On the inner peripheral surface of the yoke 11, a magnet portion 9 is provided at each corner portion 12. Each magnet unit 9 is composed of two magnets 9a and 9b, and the light receiving side magnet 9a and the imaging side magnet 9b are fixed side by side in the optical axis direction. Each of the magnets 9a and 9b has an inner peripheral side surface formed in an arcuate shape, and the outer peripheral side surface is a surface along the corner shape of the yoke 11. The closer to the corner portion 12 of the yoke 11, the thicker the thickness. ing.

  The light receiving side magnet 9a and the imaging side magnet 9b are magnetized with different magnetic poles on the radially outer side and the inner side of the lens support, respectively. For example, as shown in FIG. The light-receiving side magnet 9a has an S-pole on the inner peripheral side and an N-pole on the outer peripheral side, and the imaging-side magnet 9b is magnetized on the N-pole on the inner peripheral side and the S-pole on the outer peripheral side.

  The coil bodies 7 a and 7 b are fixed to the outer peripheral surface of the lens support 5 and move together with the lens support 5.

  The two coil bodies 7a and 7b are a light receiving side coil body 7a and an imaging side coil body 7b, which are arranged side by side in the optical axis direction of the lens. The light-receiving-side coil body 7a and the imaging-side coil body 7b have the coil wires wound in the same direction, and the coil wiring is arranged so that current flows through the two coil bodies 7a and 7b in opposite directions. Connected in series. A coil spacer 19 is disposed between the light receiving side coil body 7a and the imaging side coil body 7b, and a space is provided between the two coil bodies 7a and 7b.

  The coil wires of the light receiving side coil body 7a and the imaging side coil body 7b are electrically connected in series.

  The lens support 5 has a cylindrical shape and is disposed on the inner peripheral side of the yoke 11 and the magnet unit 9.

  A light receiving side spring 13 is attached to the light receiving side end of the lens support 5, and an image forming side spring 14 is attached to the imaging side end, and the lens support 5 is moved relative to the housing 2. Hold it possible.

  The light receiving side spring 13 and the image forming side spring 14 are annular leaf springs (see FIG. 1), and the inner peripheral side end 13a of the light receiving side spring 13 is fixed to the lens support 5, and the outer peripheral side end 13b. Is fixed between the yoke 11 and the frame 15. An inner peripheral end 14 a of the image forming side spring 14 is fixed to the lens support 5, and an outer peripheral end 14 b is fixed to the base 17 by being pressed by an insulating spacer 21 from the frame 15 side. The insulating spacer 21 insulates between the imaging side spring 14 and the yoke 11.

  The imaging-side spring 14 is an annular leaf spring as a whole, but in the present embodiment, the imaging-side spring 14 is composed of one side 30 and the other side 32 that are divided into left and right.

  A terminal 33 is formed on one side 30 constituting the imaging-side spring 14, and a terminal 35 is formed on the other side 32, so that each terminal 33, 35 is connected to a power supply terminal. ing. The one side portion 30 and the other side portion 32 are electrically connected to the coil bodies 7a and 7b by soldering or the like, respectively, so that the coil bodies 7a and 7b are energized from the imaging side spring 14. It has become.

  The light receiving side spring 13 and the image forming side spring 14 are flat in a natural state before assembly (a state before the frame 15 is assembled) (see FIG. 1), but at least the light receiving side spring 13 is assembled. Afterward, as shown in FIG. 2, the inner peripheral side portion 13a is attached in a state of being elastically deformed so as to be positioned in front of the outer peripheral side portion 13b. Thus, the inner peripheral side portion 13a is constantly urged by the urging force of the lens support 5 toward the base 17 by the restoring force (biasing force) of the spring.

  Next, functions and effects of the lens driving device 1 according to the present embodiment will be described. As shown in FIG. 3, in the magnet portion 9, in the magnets 9a and 9b provided along the optical axis direction, a magnetic field is generated by the magnetic force lines T from the N pole to the S pole on the side facing the coil bodies 7a and 7b. Therefore, when currents in different directions flow through the light receiving side coil body 7a facing the S pole of the light receiving side magnet 9a and the imaging side coil body 7b facing the N pole of the imaging side magnet 9b, Electromagnetic force (thrust) in the same direction acts on the direction 3 of the optical axis X (see FIG. 2), and the lens support 5 is driven in one direction by a plurality of thrusts.

  Then, the lens support 5 stops when the driving force of the lens support 5 and the biasing force of the light receiving side spring 13 and the imaging side spring 14 are balanced.

  In the present embodiment, since the yoke 11 is disposed only on the outer peripheral side (one side) of the magnet unit 9, the magnetic field strength acting on one coil body 7a or 7b is sandwiched (enclosed) by the yoke. ) Since the lens support 5 is driven by the resultant force acting on the plurality of coil bodies 7a and 7b, a sufficient thrust can be obtained.

  The light receiving side coil body 7a moves in the area of the light receiving side magnet 9a facing, but the moving range is just before the imaging side coil body 7b faces the light receiving side magnet 9a (the coil spacer 19 moves the imaging side magnet 9b). It is limited to the range of (before passing). This is because, if the imaging-side coil body 7b is at a position facing the light-receiving side magnet 9a, a thrust in the reverse direction is generated and the driving force is reduced. Therefore, thrust reduction can be suppressed with a simple configuration, and stable thrust management and control can be performed.

  The yoke 11 is disposed only on the outer peripheral side (one side) of the magnet portion 9 and has a single plate shape. Therefore, the yoke 11 can have a simple structure, and the dimensions in the radial direction can be made to be U-shaped in cross section. Compared with the case where it forms, it can make small and can achieve size reduction of a lens drive device.

  By arranging the magnet portion 9 at the corner portion 12 of the square cylindrical yoke 11, it is not necessary to arrange the magnets 9 a and 9 b on the side surface 10 of the yoke 11, and between the side surface 10 of the yoke 11 and the lens support 5. The dimensions can be reduced. Moreover, the thickness of the magnets 9a and 9b in the corner portion 12 can be increased, and the magnetic field strength of the magnet in the corner portion 12 can be increased.

  At the time of manufacturing the lens driving device 1, as shown in FIG. 1, the yoke 11, the magnets 9a and 9b, and the coil bodies 7a and 7b are simply assembled in the radial direction of the lens support body 5, and the assembly is easy.

  Adjacent coil bodies 7a and 7b have coil wires electrically connected in series so that the winding direction of the coil wires is the same direction and currents in opposite directions flow. And the configuration is simple.

  Next, a second embodiment of the present invention will be described with reference to FIG. 4. In the embodiment described below, the same parts as those in the first embodiment described above are the same. The description of the portion is omitted by attaching the reference numerals, and the following description will mainly explain the differences from the first embodiment.

  In the lens driving device 1 according to the second embodiment, no spacer is provided between the two coil bodies 7a and 7b, and the magnet spacer 25 is provided between the light receiving side magnet 9a and the imaging side magnet 9b in the magnet unit 9. ing.

  In the second embodiment, the spacers 25 are arranged between the adjacent magnets 9a and 9b in the moving direction of the lens support 5 so as to be spaced apart from each other, so that the coil bodies 7a and 7b face each other. , 9b can be suppressed, and the influence of the magnetic field acting in the opposite direction on the adjacent magnet can be made difficult. Therefore, similarly to the first embodiment described above, the thrust reduction can be suppressed with a simple configuration, and stable thrust management and control can be performed.

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

  For example, in the first embodiment, the magnet spacer 25 may be provided between the two magnets 9a and 9b as in the second embodiment.

  In the first and second embodiments, the number of the coil bodies 7a and 7b and the magnets 9a and 9b is not limited to two, but may be three, and the number of coil bodies and magnets is not limited.

  The magnet unit 9 is not limited to providing a plurality of separate magnets, and uses magnets magnetized with different magnetic poles in a plurality of regions obtained by dividing one magnetic body in the optical axis direction of the lens support 5. May be.

  The light receiving side coil body 7a and the imaging side coil body 7b may be wound with a coil wire in the opposite direction, and the wiring of the coil may be connected in series so that a current in the opposite direction flows through each coil body.

  The light receiving side coil body 7a and the imaging side coil body 7b are wound in the same direction, and currents in different directions are separately passed through the light receiving side coil body 7a and the imaging side coil body 7b. It may be.

It is a disassembled perspective view of the lens drive device concerning a 1st embodiment. It is a longitudinal cross-sectional view of the lens drive device concerning 1st Embodiment. FIG. 3 is an enlarged cross-sectional view illustrating a portion A shown in FIG. 2 in order to explain the operation of the lens driving device according to the first embodiment. It is a longitudinal cross-sectional view of the lens drive device concerning 2nd Embodiment.

DESCRIPTION OF SYMBOLS 1 Lens drive device 2 Case 3 Lens 5 Lens support body 7a Light reception side coil body 7b Image formation side coil body 9 Magnet part 9a Light reception side magnet 9b Image formation side magnet 11 Yoke 13a Light reception side spring 13b Image formation side spring 19 For coils Spacer 25 Spacer for magnet

Claims (1)

A cylindrical lens support that holds the lens, a coil body that is fixed to the outer periphery of the lens support, a plurality of magnet portions that are provided on the outer periphery of the coil body and arranged to face the coil body, and an outer periphery of the plurality of magnet portions Electromagnetic force generated by supplying power to the coil body, including a provided yoke, a housing that holds the yoke and the magnet unit, and a spring that supports the lens supporter so as to be movable in the optical axis direction of the lens. In the lens driving device for driving the lens support in the direction of the optical axis of the lens,
Each magnet part is polarized in the N-pole and S-pole in the radial direction and includes a plurality of different magnetic poles in the optical axis direction of the lens, and the yoke has a rectangular tube shape. Each magnet part is arranged on the inner peripheral side, and a plurality of coil bodies are provided in the optical axis direction corresponding to the respective magnetic poles in the optical axis direction of the magnet part, and currents in opposite directions are supplied to adjacent coil bodies. A lens driving device characterized by flowing a current.

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