JP5066734B2 - Lens driving device, camera and camera-equipped mobile phone - Google Patents

Description

  The present invention relates to a lens driving device for autofocus used for a small camera, a camera including the lens driving device, and a mobile phone with a camera.

  In this type of lens driving device, as shown in FIG. 12, Patent Document 1 includes a yoke 101 having an annular shape with a U-shaped cross section in the lens optical axis direction. It is disclosed that the lens support 103 is disposed and the lens support 103 is moved back and forth in the optical axis direction.

  In the technique of Patent Document 1, a magnet 107 is fixed to the inner peripheral surface of the outer peripheral side wall 105 of the yoke 101, and the magnet 107 is provided with a space between the inner peripheral side wall 109 and fixed to the lens support 103. The coil 111 is disposed between the inner peripheral side wall 109 of the yoke 101 and the magnet 107. The magnet 107 is provided over the entire circumference of the yoke 101 in the circumferential direction.

  The lens support 103 of Patent Document 1 is provided with a flange 113 projecting radially outward of the lens support 103 at the rear end thereof, and the rear end of the coil 111 is bonded and fixed to the flange 113. The flange 113 is provided over the entire circumference of the lens support 103.

JP 2006-58662 A

  However, in the above-described conventional lens driving device, the movement of the lens support 103 is limited to the distance H between the rear end of the inner peripheral wall 109 of the yoke 101 and the flange 113 of the lens support 103. was there.

  The rear end of the inner peripheral side wall 109 and the rear end of the outer peripheral side wall 105 of the yoke 101 require a dimension obtained by adding the dimension of the thickness 113 of the flange 113 and the moving distance H of the lens support to the inner peripheral side wall 109. Therefore, there is a limit in reducing the size of the yoke 101 in the moving direction (optical axis direction) of the lens support.

  Further, since the dimension in the optical axis direction of the inner peripheral side wall 109 of the yoke is made shorter than the outer peripheral side wall 105 by the dimension of the moving distance H of the lens support, the coil 111 is magnetized over the entire moving region. 107 and the inner peripheral side wall 109 of the yoke 101 cannot be sandwiched, and there is a possibility that a magnetic field cannot be effectively applied to the coil 111.

  Accordingly, the present invention provides a lens driving device, a camera, and a camera-equipped mobile phone that can effectively act on a coil with a magnetic field formed by a magnet and a yoke and can be downsized in the moving direction (front-rear direction) of the lens support. The purpose is to provide.

  The invention according to claim 1 includes an annular yoke, a lens support body disposed on the inner peripheral side of the yoke and having a coil fixed to the outer periphery, a plurality of magnets, and a spring. The magnet has a side wall, an outer peripheral side wall, and a connecting wall that connects the outer peripheral side wall and the inner peripheral side wall with a space therebetween, and the magnet is fixed to the inner peripheral surface of the outer peripheral side wall with a space therebetween. The coil is disposed between the inner peripheral side wall of the yoke and the outer peripheral side wall or the magnet, and the spring is disposed between the yoke and the lens support. A lens driving device which is provided and supports the lens support so as to be movable in the optical axis direction relative to the yoke, and moves the lens support back and forth along the optical axis direction of the lens by electromagnetic force generated by energizing the coil And the contour of the yoke The plan view seen from the front side or the rear side of the support has a polygonal shape, the inner peripheral side wall is an arc, magnets are provided only at the corners of the contour of the yoke, and adjacent to the inner peripheral side wall of the yoke The lens driving device is characterized in that a cut portion is provided at a position corresponding to between the magnets.

  According to a second aspect of the present invention, there is provided a camera comprising the lens driving device according to the first aspect and an image sensor provided on an optical axis.

  According to a third aspect of the present invention, there is provided a camera-equipped mobile phone including the camera according to the second aspect.

According to the first aspect of the invention, for example, in the yoke shown in FIG. 9B, a magnetic field BA is generated from the magnet toward the inner peripheral wall facing the magnet, and this magnetic field BA is used for driving the lens support. Since there is no inner peripheral side wall at a position corresponding to between adjacent magnets, only an effective magnetic field BA can be obtained. That is, when the inner peripheral wall and the outer peripheral side wall are continuous walls in the circumferential direction, as shown in the comparative example in FIG. The magnetic field BT in the direction is induced, and the reverse magnetic field BT causes a reverse thrust to act on the coil to inhibit the driving of the lens driving device. According to the present invention, the position corresponding to between adjacent magnets Since a cut portion is provided and there is no inner peripheral side wall, generation of thrust in the reverse direction can be prevented.
Therefore, according to the first aspect of the present invention, the driving efficiency of the lens support can be increased.

  In the corner portion that defines the outline of the yoke, the gap between the inner peripheral side wall and the outer peripheral side wall can be widened. Therefore, the thickness of the magnet can be increased, so that the magnetic field strength can be increased.

  According to the invention described in claim 2, it is possible to provide a camera having the function and effect described in claim 1.

  According to the invention described in claim 3, it is possible to provide a camera-equipped mobile phone having the function and effect described in claim 2.

  Hereinafter, a first embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is an exploded perspective view of the lens driving device according to the first embodiment of the present invention, FIG. 2 is an exploded perspective view showing the lens support body to which the coil shown in FIG. 1 is fixed, and FIG. 2 is an enlarged perspective view showing a coil fixing portion of the lens support shown in FIG. 2, FIG. 4 is a plan view of the lens support to which the coil is fixed, as viewed from the rear side, and FIG. FIG. 6 is a perspective view of the lens driving device shown in FIG.

  The lens driving device 1 according to the first embodiment is a lens driving device for an autofocus camera incorporated in a mobile phone. The lens driving device 1 includes an annular yoke 3, a lens support 7, a front spring 9, a rear spring 11, a base 5 (housing) disposed on the rear side of the yoke 3, and a front side of the yoke. The lens support 7 has a coil 15 fixed to the outer periphery thereof. An insulator (spacer) 17 is disposed between the yoke 3 and the rear spring 11. This lens driving device 1 is very small with about 10 mm in length and width and about 3.5 mm in height.

  The yoke 3 has a quadrilateral outer periphery when viewed from the front side and a circular inner periphery when viewed from the front, and the outer peripheral side wall 3a, the inner peripheral side wall 3b, and the outer peripheral side wall 3a and the inner peripheral side wall 3b are spaced apart. The outer peripheral side wall 3a, the inner peripheral side wall 3b, and the connecting wall 3c have a U-shaped cross section. The outer peripheral side wall 3a and the inner peripheral side wall 3b have the same dimension in the moving direction (front-rear direction) of the lens support 7. On the inner peripheral side wall 3b, a cut portion 12 is formed from the rear end toward the front. The cut portions 12 are arranged at equal intervals in the circumferential direction. In the present embodiment, the cut portions 12 are provided at positions corresponding to between the adjacent corner portions 14 (side portions) on the outer peripheral side wall 3a having a rectangular shape in plan view. It is.

  At each corner 14 of the yoke 3, a magnet 13 is fixed to the inner peripheral surface of the outer peripheral side wall 3a. The magnet 13 is provided only at the corner portion 14 and is not located at a position corresponding to the cutout portion 12 formed in the inner peripheral side wall 3b.

  The lens support 7 has a substantially cylindrical shape. A lens (not shown) is attached to the inner periphery of the lens support 7 so that the inner periphery of the yoke 3 can be moved in the optical axis direction. An annular coil 15 is mounted on the outer periphery of the lens support 7, and the coil 15 is bonded and fixed to a coil fixing portion 19 provided integrally with the lens support 7.

  The coil 15 is disposed between the outer peripheral side wall 3 a and the inner peripheral side wall 3 b of the yoke 3, but the magnet 13 is positioned between the magnet 13 and the inner peripheral side wall 3 b at the corner portion 14 where the magnet 13 is located. 3 is moved in the front-rear direction.

  As shown in FIG. 2, the coil fixing portion 19 is arranged at intervals in the circumferential direction of the outer peripheral surface of the lens support 7, and a cut portion (space portion) 12 provided on the inner peripheral side wall 3 b of the yoke 3. (Refer to FIG. 1 and FIG. 5).

  The coil fixing portion 19 is integrally provided with an inner peripheral receiving surface 21 that receives the inner peripheral surface of the coil 15 mounted on the lens support 7 and a rear end receiving surface 23 that receives the rear end of the coil 15. The inner peripheral receiving surface 21 is provided along the outer peripheral surface of the lens support 7, and the rear end receiving surface 23 is provided so as to protrude radially outward of the lens support, and the inner peripheral receiving surface 21 and the rear end are provided. The receiving surface 23 forms an L-shaped cross section. The coil 15 is bonded and fixed on two surfaces, an inner peripheral receiving surface 21 and a rear end receiving surface 23.

  As shown in FIG. 3, in the coil fixing portion 19, the rear end receiving surface 23 is provided with an adhesive reservoir 25 recessed in the rear side, and the inner peripheral receiving surface 21 communicates with the adhesive reservoir 25. An adhesive moving groove 27 in the front-rear direction is provided. The adhesive movement groove 27 is a groove having a width of 1 mm or less (0.2 mm in the present embodiment). When the adhesive is injected into the adhesive reservoir 25, the adhesive movement groove 27 is caused by capillary action. Moves to supply an adhesive between the inner peripheral receiving surface 21 and the coil 15.

  As shown in FIG. 1, the base 5 has an outer wall 5a located on the outer periphery of the yoke 3, and a base portion 5b located on the rear side of the yoke 3 (the rear side in the optical axis direction of the lens). The outer peripheral side portion 11b of the rear spring 11 is placed on the base portion 5b of the fifth portion.

  The front spring 9 is an annular leaf spring, and is provided with an inner peripheral side portion 9a and an outer peripheral side portion 9b. The inner peripheral side portion 9a is attached to the lens support 7, and the outer peripheral side portion 9b is connected to the yoke 3. It is sandwiched and fixed between the frame 6. The inner peripheral side portion 9a and the outer peripheral side portion 9b are connected by an elastically deformable arm portion 9c.

  Although the rear spring 11 is an annular leaf spring as a whole, in this embodiment, the rear spring 11 is composed of one side portion 30 and the other side portion 32 which are divided into left and right. The outer peripheral side portions 11 b and 11 b of the rear spring 11 are sandwiched between the base 5 and the yoke 3 via an insulator (spacer) 17, and the insulator 17 is formed between the rear spring 11 and the yoke 3. The electrical insulation between them is intended. The inner peripheral side portions 11 a and 11 a are attached to the rear end of the lens support 7. Each inner peripheral side portion 9a and outer peripheral side portion 9b of the rear spring 11 are connected by an elastically deformable arm portion 11c.

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

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

  The frame 6 is disposed on the front side of the lens support 7, holds the outer peripheral side portion 9 b of the front spring 9 between the yoke 3, and fits and fixes to the base 5 to fix the base 5 and the frame 6. The casing is formed with.

  Next, operations and effects of the lens driving device 1 according to the first embodiment will be described.

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

  Since the coil fixing portion 19 projecting outward in the radial direction of the lens support 7 is located at the cutout portion 12 formed on the inner peripheral side wall 3b of the yoke 3, the movement of the lens support 7 is not hindered.

  Since the magnet 13 is disposed at the corner 14 of the yoke 3, the corner 14 can have a wide space between the inner peripheral side wall 3b and the outer peripheral side wall 3a. Therefore, the magnetic field strength can be increased with a compact configuration.

  In the corner portion 14 of the yoke 3, as shown in FIG. 5, the coil portion 15a at the corresponding position faces the magnet 13, and the outer peripheral side wall 3a of the yoke 3 and the outer periphery over the entire moving region of the coil portion 15a. Since it is sandwiched between the side walls 3b, it can always move in a strong magnetic field, and a high driving torque can be obtained.

  The coil fixing portion 19 is provided at an interval on the outer periphery of the lens support 7, and is not provided with a flange that protrudes over the entire circumference at the rear end in the optical axis direction and radially outward as in the prior art. Therefore, it is not necessary to provide the yoke 3 with the conventional flange thickness T and moving space H (see FIG. 12). Accordingly, the yoke 3 does not require a dimension including the flange thickness T and the moving space H between the rear end of the inner peripheral side wall 3b and the rear end of the outer peripheral side wall 3a. The dimension in the direction of movement of the support can be made smaller than before.

  Since the coil 15 fixes the coil 15 on the two surfaces of the inner peripheral receiving surface 21 and the rear end receiving surface 23, the coil 15 can be firmly fixed.

  The coil fixing part 19 is provided with an adhesive reservoir 25 on the rear end receiving surface 23 and an adhesive movement groove 27 communicating with the adhesive reservoir 25 on the inner peripheral receiving surface 21. In the step of fixing the coil, the adhesive is injected into the adhesive reservoir 25, and the coil 15 is mounted on the coil fixing portion 19, so that the adhesive in the adhesive reservoir 25 forms the adhesive movement groove 27 by capillary action. Since it moves, the coil 15 can be bonded and fixed to the inner peripheral receiving surface 21 and the rear end receiving surface 23. That is, only by injecting the adhesive into the adhesive reservoir 25, the two surfaces of the coil can be bonded, and manufacturing is easy. The coil 15 is fixed in the manufacturing process by placing the lens support 7 on the jig with the rear end receiving surface 23 facing down and injecting the adhesive into the adhesive reservoir 25, and then attaching the coil to the adhesive. It fixes by heating in a heat tank, pressing toward the reservoir 25.

  Further, since the coil 15 is mounted on the inner peripheral surface receiving surface 21 provided with four inner peripheral surfaces, the coil 15 can be easily centered (positioned).

  Other embodiments of the present invention will be described below. In the embodiments described below, the same reference numerals are given to the portions having the same effects as those of the first embodiment described above. Therefore, the detailed description of the portion is omitted, and in the following description, differences from the first embodiment will be mainly described.

  7 to 9 show a second embodiment. FIG. 7 is an exploded perspective view of the lens driving device according to the second embodiment of the present invention as viewed from the front side, and FIG. 8 is an exploded perspective view of the lens driving device according to the second embodiment as viewed from the rear side. FIG. 9A is a perspective view of the yoke on which the magnet is mounted as seen from the rear side, and FIG. 9B is a plan view for explaining the direction of the magnetic field.

  In the second embodiment, the cut portion (space) 12 is provided on the inner peripheral side wall 3b of the yoke 3 from the viewpoint of driving efficiency regardless of the position of the coil fixing portion 21 of the lens support 7. That is, as shown in FIG. 9A, in the yoke 3 whose outer contour is rectangular in plan view, the outer peripheral side wall 3 a is formed along the contour of the yoke 3 in the circumferential direction. The inner periphery of the yoke 3 is circular in plan view, and the inner peripheral side wall 3b is provided on a part of the inner periphery of the yoke 3, and has an arc shape in plan view. The inner peripheral side wall 3b is provided only at a position facing the magnet 13, and a cut portion 12 is provided at a position corresponding to between the adjacent magnets 13 and 13, so that the inner peripheral side wall 3b is not provided. .

  According to the second embodiment, as shown in FIG. 9B, a magnetic field BA is generated in the yoke 3 from the north pole of the magnet 13 toward the inner peripheral side wall 3b facing the magnet 13, and this magnetic field BA is The magnetic field contributes to driving the lens support. Since a cut portion (space portion) 12 is provided at a position corresponding to the adjacent magnets 13 and 13 and there is no inner peripheral side wall 3b, only an effective magnetic field BA can be obtained. That is, although a comparative example is shown in FIG. 11, in this comparative example, the inner peripheral side wall 3b and the outer peripheral side wall 3a are respectively continuous walls in the circumferential direction, and as shown in FIG. In 3b, a reverse magnetic field BT is induced in a portion located between the adjacent magnets 13 and 13, and a reverse thrust acts on the coil 15 to obstruct driving of the lens driving device. According to the present embodiment, it is possible to prevent the occurrence of such reverse thrust. Therefore, according to the second embodiment, the driving efficiency of the lens support 7 can be increased.

  In the first embodiment as well, the inner peripheral side wall 3b is not provided at the position corresponding to the adjacent magnets 13 and 13 and the cut portion (space) 12 is formed. Therefore, as in the second embodiment. Only an effective magnetic field BA can be obtained.

  FIG. 10 shows a third embodiment. FIG. 10A is a perspective view of the yoke 3 on which the magnet is mounted as viewed from the rear side, and FIG. 10B is a plan view for explaining the direction of the magnetic field.

  In the third embodiment, the inner peripheral side wall 3b of the yoke 3 is formed continuously in the circumferential direction, and the cutout portion (space) 12 is provided in the outer peripheral side wall 3b of the yoke 3. The form is different. That is, as shown in FIG. 10A, in the yoke 3 whose outer periphery is rectangular in plan view, the outer peripheral side wall 3a is provided only at the corner of the yoke 3 having a rectangular outline, and the inner peripheral side wall 3b is It is provided continuously along the circumferential direction along the circular inner periphery. The outer peripheral side wall 3 a of the yoke 3 is provided only at the corner where the magnet 13 is disposed, and there is no outer peripheral side wall 3 a between the adjacent magnets 13, 13, thereby forming a space 12.

  In the third embodiment, as shown in FIG. 10B, a magnetic field BA is generated in the yoke 3 from the north pole of the magnet 13 toward the inner peripheral side wall 3b facing the magnet 13, and this magnetic field BA is supported by the lens. The magnetic field contributes to the driving of the body 7. Since the position (space part) 12 corresponding to between the adjacent magnets 13 and 13 does not have the outer peripheral side wall 3a and is the space 12, only an effective magnetic field BA can be obtained. Drive efficiency can be increased.

  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 number of coil fixing portions 19 is not limited to four, and any number may be provided, and the cutout portion 12 is the same on the inner peripheral side wall 3 b of the yoke 3 corresponding to the coil fixing portion 19. It is sufficient to provide only the number.

  The shape of the outer peripheral side wall 3a of the yoke 3 (outer shape of the yoke) is not limited to a rectangular shape in plan view, and may be a pentagon, a hexagon, or the like. A magnet 13 is disposed at each corner 14 and the inner peripheral side wall 3b. Alternatively, the cut portion 12 may be provided corresponding to the position between the corner portions, and the coil fixing portion 19 positioned at the cut portion 12 may be provided on the outer periphery of the lens support 7.

  In the third embodiment, the space 12 between the outer peripheral side walls 3a may be filled with a nonmagnetic material, for example, a resin material, or a resin case is mounted on the outer peripheral side of the yoke 5, or the base A wall surface may be provided in the circumferential direction of the frame 5 or the frame 6, and the outer periphery of the yoke may be sealed with a housing.

  Furthermore, in the third embodiment, the inner peripheral side wall 3b may be provided only at a position facing the magnet 13 and the space between the adjacent magnets 13 and 13 may be a space (cut portion) 12.

  In each of the above-described embodiments, the cut portion 12 may have a narrow width in the circumferential direction and a wide width in the circumferential direction of the inner peripheral side wall 3 a and the outer peripheral side wall 3 b so as to protrude beyond the magnet 13. .

It is a disassembled perspective view of the lens drive device concerning an embodiment of the invention. It is a disassembled perspective view which extracts and shows the lens support body which fixed the coil shown in FIG. It is a perspective view which expands and shows the coil fixing | fixed part of the lens support body shown in FIG. It is the top view which looked at the lens support body which fixed the coil from the back side. It is AA sectional drawing shown in FIG. It is a perspective view of the lens drive device shown in FIG. It is the disassembled perspective view which looked at the lens drive device which concerns on 2nd Embodiment of this invention from the front side. It is the disassembled perspective view which looked at the lens drive device concerning a 2nd embodiment from the back side. It is a figure of the yoke which concerns on 2nd Embodiment, (a) is the perspective view which looked at the yoke equipped with the magnet from the back side, (b) is a top view explaining the direction of a magnetic field. It is a figure of the yoke which concerns on 3rd Embodiment, (a) is the perspective view which looked at the yoke which mounted | wore with the magnet from the back side, (b) is a top view explaining the direction of a magnetic field. It is a figure of the yoke which concerns on a comparative example, (a) is the perspective view which looked at the yoke with which the magnet was mounted | worn from the rear side, (b) is a top view explaining the direction of a magnetic field. It is sectional drawing which cut | disconnects and shows the conventional lens drive device in the same position as the AA position of FIG.

DESCRIPTION OF SYMBOLS 1 Lens drive device 3 Yoke 3a Outer peripheral side wall 3b Inner peripheral side wall 3c Connection wall 7 Lens support body 9 Front side spring 11 Rear side spring 12 Cutting part (space part)
13 Magnet 15 Coil

Claims (3)

An annular yoke, a lens support disposed on the inner peripheral side of the yoke and having a coil fixed to the outer periphery, a plurality of magnets, and a spring, the yoke includes an inner peripheral side wall, an outer peripheral side wall, and an outer peripheral side wall And a connecting wall for connecting the inner peripheral side wall with a space therebetween, and the magnet is fixed to the inner peripheral surface of the outer peripheral side wall with a space between the inner peripheral side wall and spaced in the circumferential direction of the yoke. The coil is disposed between the inner peripheral side wall of the yoke and the outer peripheral side wall or the magnet, and the spring is provided between the yoke and the lens support body, and the lens support body with respect to the yoke. A lens driving device that moves the lens support body back and forth along the optical axis direction of the lens by electromagnetic force generated by energizing the coil.
The outline of the yoke is a polygonal shape when viewed from the front side or the rear side of the lens support, the inner peripheral side wall is an arc, and magnets are provided only at the corners of the yoke outline.
A lens driving device characterized in that a cut portion is provided at a position corresponding to between adjacent magnets on the inner peripheral side wall of the yoke.   A camera comprising the lens driving device according to claim 1 and an image sensor provided on an optical axis.   A camera-equipped mobile phone equipped with the camera according to claim 2.

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