JP6180103B2 - Lens drive device - Google Patents

Description

  The present invention relates to a lens driving device that adjusts a focal point or changes a focal length by moving a lens in an optical axis direction, and performs image blur correction by moving the lens in a direction orthogonal to the optical axis.

  Conventionally, there is JP 2012-103373 A as a technical document in such a field. This publication describes a lens driving device for an autofocus camera. The lens driving device includes a lens support that supports the lens, and a coil body that is fixed to the outer peripheral side of the lens support, and the coil body includes a plurality of lenses for moving the lens in the optical axis direction. It consists of a first coil and a plurality of second coils for camera shake correction. The first coil and the second coil have an oval shape and are arranged so as to surround the outer periphery of the lens support.

JP 2012-103373 A JP 2012-103558 A JP 2011-247909 A JP 2011-65140 A

  However, when a plurality of coils are arranged so as to surround the outer periphery of the lens support as described above, there is a problem that the apparatus cannot be miniaturized because the space occupied by the coils is large. In addition, when a plurality of oval coils are used as described above, the area occupied by curved portions (hereinafter referred to as R portions) located on both sides of the coil increases according to the number of coils. An increase in area also hinders downsizing of the apparatus.

  Accordingly, an object of the present invention is to provide a lens driving device in which the device is miniaturized by effectively using the space inside the device.

  In order to solve the above problems, the present invention provides a lens driving device that moves a lens in the direction of the optical axis with respect to the base portion, and a movable frame that is supported on the base portion so as to be movable in the direction of the optical axis; A drive unit that moves the movable frame in the direction of the optical axis in cooperation with the coil and the magnet, and the base unit has a quadrangular shape in a plane orthogonal to the optical axis, and the coil is The coil is fixed in the vicinity of one side, and the end of the coil is bent inward so as to be separated from the corner of the base.

  If the number of coils is reduced, the area occupied by the R portion is reduced, so that useless space can be reduced and the apparatus can be downsized. However, in general, when the number of coils is reduced, the driving force is reduced. Therefore, in order to obtain a desired driving force, it is necessary to increase the size of the coil, and by increasing the size of the coil. There is a risk that downsizing of the apparatus may be hindered. Therefore, in order to reduce the size of the device, it is necessary to effectively use the space inside the device in order to reduce the overall size of the device even if the coil size is increased. In order to effectively use the space inside the apparatus, it is necessary to consider the position of the coil and the shape of the base portion. In view of the above, considering that the lens is first arranged at the center of the base portion, the lens can be enlarged by setting the position away from the center of the base portion. As for the shape of the base portion, for example, when the base portion is circular, the large coil cannot be arranged at a position away from the center of the base portion unless the size of the base portion is increased. It is not preferable because it cannot be converted. Therefore, when the base portion is rectangular, the coil can be disposed along one side of the base portion, and the large coil can be disposed at a position away from the center of the base portion. In view of the above, in the present invention, since the base portion has a rectangular shape and the coil is disposed in the vicinity of one side of the base portion, it is possible to effectively utilize the space in the vicinity of one side of the base portion. In addition, it is not necessary to increase the size of the base portion as compared with the case where the base portion is circular, which contributes to downsizing of the apparatus. And since the edge part of a coil is bent and arrange | positioned inside so that it may space apart from the corner part of a base part, a coil can be enlarged more and a desired big driving force can be obtained.

In addition, a lead for transmitting a drive signal for moving the movable frame in the direction of the optical axis to the coil is provided, and a part of the lead is disposed inside the coil.
According to this lens driving device, a part of the lead enters the inside of the coil. Therefore, since the space inside the coil can be effectively used as a space for arranging the leads, the space inside the device can be effectively used to contribute to downsizing of the device.

A plurality of magnets are provided, and the magnets face each of the end portions of the coil in a plane perpendicular to the optical axis.
In order to obtain a desired large driving force, the direction of the magnetic field of the magnet is preferably orthogonal to the surface of the coil. However, when one bent magnet faces the coil, the direction of the magnetic field of the magnet is not perpendicular to the surface of the tilt coil at the end of the coil, so that the driving force cannot be fully exerted. Therefore, in the present invention, since each of the plurality of magnets faces the end of the coil, the direction of the magnetic field of the magnet is orthogonal to the surface of the coil, and the driving force can be sufficiently exerted. .

Further, the base portion includes a protrusion that protrudes in the direction of the optical axis from the vicinity of one side of the base portion, and the protrusion has a recess for fitting the coil in the direction of the optical axis.
According to this lens driving device, the device can be easily assembled because the coil can be simply fixed to the base portion simply by fitting the coil into the recess of the base portion.

  According to the present invention, the apparatus can be miniaturized by effectively using the space inside the apparatus.

It is a perspective view which shows the lens drive device which concerns on this embodiment. It is a perspective view which shows the state which removed the cover part of the lens drive device of FIG. It is a disassembled perspective view which shows the lens drive device of FIG. It is a disassembled perspective view which shows the lens drive device of FIG. It is a perspective view which shows a movable frame and FPC. It is a perspective view which shows a base part and a coil. It is sectional drawing which shows a base part and a coil. It is sectional drawing which shows a base part and a movable frame. It is sectional drawing which shows a movable frame and a lens holding frame.

  Hereinafter, a preferred embodiment of a lens driving device according to the present invention will be described in detail with reference to the drawings.

  The lens driving device shown in FIG. 1 is used in a digital camera, a mobile phone, or a smartphone that performs image shake correction, and is in front of a CCD [Charge Coupled Device] image sensor or a CMOS [Complementary Metal Oxide Semiconductor] image sensor that is an imaging device. It is arranged and used.

  As shown in FIGS. 1 to 3, the lens driving device 1 includes a rectangular parallelepiped lid body 2, a rectangular base portion 3 for closing the opening of the lid body 2, and focus adjustment for adjusting a focal length. A flexible printed circuit board for focus adjustment (hereinafter referred to as FPC) 5 for ensuring electrical connection between the drive unit (drive unit) 4 and an external circuit, an image blur correction drive unit 6 and an external circuit. An image blur correction FPC 7 for ensuring electrical connection and a substantially cylindrical lens barrel 8 that houses at least one lens R are provided. In the following description, the direction perpendicular to the optical axis C of the lens R is defined as the X axis, and the direction perpendicular to the optical axis C direction and the X axis is defined as the Y axis.

  The lid 2 is a box-shaped member having a circular opening 2a centered on the optical axis C of the lens R, and the base 3 is a rectangular frame having a circular opening 3a centered on the optical axis C. And is a quadrangular shape on a plane orthogonal to the optical axis C. The lens barrel 8 holds the lens R in a state where the lens R is exposed from the opening 2a and the opening 3a. The base 3 has a protrusion 3b that protrudes in the direction of the optical axis C from one side of the peripheral edge of the base 3, and a rectangular opening 3c is formed at the center of the protrusion 3b. . An H-shaped resin insulating plate 9 fixed to the front end 5a of the FPC 5 enters the opening 3c and closes the opening 3c.

  The FPC 7 has an extended portion 7 c extending outward from the lid body 2 and the base portion 3, and a bifurcated branch portion 7 a in a portion close to the lid body 2 and the base portion 3. As shown in FIG. 2, the bifurcated portion 7 a of the FPC 7 is fixed by being sandwiched between the locking projections 3 g of the base portion 3 inside the lid body 2. Further, the inner end of each of the branch portions 7a is fixed to the movable frame 10, and a return yoke 11 for amplifying the attractive force of the magnets 6a and 6b of the image blur correction drive unit 6 is provided outside the tip portion 7b. It is fixed. A Hall element 12 for magnetic detection is fixed to the tip 7b on the surface opposite to the surface on which the return yoke 11 is fixed (see FIG. 3).

  The movable frame 10 is supported by the base portion 3 so as to be movable in the direction of the optical axis C. As shown in FIGS. 3 to 5, the movable frame 10 includes a circular opening 10 a centered on the optical axis C, an oval coil loading portion 10 b formed at each corner on one side, and a spherical body. 13 has three ball mounting recesses 10c (see FIG. 5). The lens barrel 8 is inserted into the opening 10a, and the coils 6c and 6d having an oval shape of the image blur correction driving unit 6 are fitted and fixed to the coil loading unit 10b. The movable frame 10 includes a magnet holding portion 10e that protrudes in the direction of the optical axis C on one side of the peripheral edge of the movable frame 10, and a magnet holding portion 10e that is a corner of the movable frame 10 with the optical axis C interposed therebetween. And two projecting portions 10f provided on the opposite side.

  The magnet holding portion 10e is formed in a crescent shape when viewed from the optical axis C direction, and both end portions 10g of the magnet holding portion 10e are notched in a semi-cylindrical shape and extend in the optical axis C direction. A ball receiving portion 10h is provided. Two spheres 15 enter one sphere receiving portion 10h, and one sphere 15 enters the other sphere receiving portion 10h, but two spheres 15 enter the other sphere receiving portion 10h. One sphere 15 may enter one of the ball receiving portions 10h.

  As shown in FIG. 6 and FIG. 7, three support portions 3 f formed at both ends of the protrusion 3 b of the base portion 3 are formed with three ball receiving portions 3 d cut out in a semi-cylindrical shape, Each ball receiving portion 3d is formed at a position corresponding to the above-described ball receiving portion 10h. Further, a fitting recess 3e for fitting the coil 4a and the yoke 16 of the focus adjustment driving unit 4 is formed inside the support column 3f. The fitting recess 3e is inclined about 45 degrees with respect to one side 3z of the base portion 3 so as to be separated from the corner portions 3x and 3y of the base portion 3 when viewed from the optical axis C direction. Each fitting recess 3e extends in the direction of the optical axis C inside the column portion 3f, and each fitting recess 3e sandwiches the end 4c of the coil 4a and the yoke 16 so that the coil 4a and the yoke 16 is fitted to the base portion 3 in the optical axis C direction.

  The coil 4a is wound in an air-core shape so that the winding axis is orthogonal to the optical axis C. The coil 4a is provided in the vicinity of one side 3z of the base portion 3 having a quadrangular shape in a plane orthogonal to the optical axis C, and both ends of the coil 4a are corner portions located at both ends of the one side 3z of the base portion 3. The bent portions 4s and 4t are bent inward so as to be separated from 3x and 3y. The coil 4 a has a central portion 4 b that forms an upper bottom portion of a trapezoid when viewed from the optical axis C direction, and end portions 4 c that are respectively located on both sides of the central portion 4 b. It arrange | positions along the one side 3z, and the edge part 4c is bend | folded about 45 degree | times inside with respect to the center part 4b. The yokes 16 are respectively arranged outside the end portions 4c.

  Further, as shown in FIG. 5, the outer periphery of the magnet holding portion 10e of the movable frame 10 has a flat magnet fixing portion 10i extending in the optical axis C direction and the Y axis direction, and a magnet fixing portion 10i. And a magnet fixing portion 10k formed at an inclination of 45 degrees on the opposite side of the magnet fixing portion 10j with respect to the magnet fixing portion 10i. Magnets 4d, 4e, and 4f of the focus adjustment drive unit 4 are fixed to the magnet fixing units 10i, 10j, and 10k, respectively. In a state where the movable frame 10 is held by the base portion 3, the central portion 4b of the trapezoidal coil 4a faces the outside of the magnet 4d, and the respective end portions 4c of the coil 4a face the outside of the magnets 4e and 4f. (See FIG. 8).

  Further, as shown in FIGS. 6 and 7, a hall element 17 as a magnetic field detection element is disposed in a space 4g inside the central portion 4b of the coil 4a, and the hall element 17 is disposed at the front end portion 5a of the FPC 5. It is fixed. Two conductive leads 18 extending from the central portion 4b to the end portion 4c of the coil 4a are disposed on both sides of the Hall element 17 in the space 4g inside the coil 4a. These leads 18 are fixed to the front end portion 5a of the FPC 5, and transmit a drive signal for moving the movable frame 10 in the direction of the optical axis C from the FPC 5 to the coil 4a.

  The lead 18 enters the space 4g inside the coil 4a at the central portion 4b of the coil 4a. In this way, since a part of the lead 18 enters the inside of the coil 4a, the space 4g inside the coil 4a can be effectively used as a space for arranging the lead 18, and the space inside the lens driving device 1 can be saved. Effective use contributes to downsizing of the device. The curved portion 18c of the lead 18 is once bent inward near the boundary between the central portion 4b and the end portion 4c, and the end portions 18a on both sides of the lead 18 are connected to the end portions 4c and the base portion 3 on both sides of the coil 4a. The inner surface 18d of the end 18a of the lead 18 is in contact with the outer surfaces 4x and 4y of the end 4c of the coil 4a, respectively. The coil 4a is electrically connected to the coil wire at the end 4c.

  The above-described coil 4a and the magnets 4d, 4e, and 4f shown in FIG. 8 cooperate to move the movable frame 10 in the direction of the optical axis C with respect to the base portion 3, thereby adjusting the focal point and the focal length. It is possible to make changes. Further, since the yoke 16 is provided outside the end portion 4c of the coil 4a, the yoke 16 fitted to the base portion 3 is attracted to the magnets 4d, 4e, 4f fixed to the movable frame 10, and the movable frame A suction force in a direction orthogonal to the optical axis C is generated with respect to the ten base portions 3. Further, the base 3 and the movable frame 10 are sucked in a state where the sphere 15 is interposed between the ball receiving portion 10h (see FIG. 5) of the movable frame 10 and the ball receiving portion 3d (see FIG. 4) of the base portion 3. Therefore, the movable frame 10 is slidably supported on the base portion 3 via the sphere 15.

  Also, as shown in FIG. 4, the two protrusions 10f provided at the corners of the movable frame 10 are each provided with an engagement protrusion 10m, and the optical axis C of the protrusion 10f is sandwiched between them. Engagement protrusions 10n are provided on the outer sides of both end portions 10g of the magnet holding portion 10e provided on the opposite side. Each engaging protrusion 10m is engaged with an engaging hole 21a of the pressing plate 21 for preventing the lens holding frame 20 from being lifted, and each engaging protrusion 10n is respectively engaged with the engaging hole 21b of the pressing plate 21. Combined. Thereby, the movable frame 10 and the pressing plate 21 are fixed in a state where the lens holding frame 20 is sandwiched.

  As shown in FIG. 9, the lens holding frame 20 that holds the lens barrel 8 is supported so as to be movable in the direction perpendicular to the optical axis C with respect to the movable frame 10. The lens holding frame 20 has a circular opening 20a for fitting the lens barrel 8, a magnet fitting hole 20b for fixing the magnets 6a and 6b, and suction for sucking the lens holding frame 20 and the movable frame 10 together. A magnet fitting recess 20c for fixing the magnet 22 and a ball receiving recess 20d (see FIG. 4) for receiving the sphere 13 are provided.

  Two magnet fitting holes 20b are provided at positions corresponding to the coil loading portion 10b (see FIG. 6) of the movable frame 10. The magnets 6a and 6b fitted in the magnet fitting hole 20b face the coils 6c and 6d fitted in the coil loading portion 10b in the optical axis C direction. The lens holding frame 20 can move in the direction orthogonal to the optical axis C with respect to the movable frame 10 and perform image blur correction by the cooperation of the coils 6c and 6d and the magnets 6a and 6b.

  Three magnet fitting recesses 20c are provided, and in each magnet fitting recess 20c, a quadrupole magnetized attraction magnet 22 is fitted. Further, as shown in FIG. 5, the movable frame 10 has three metal piece insertion portions 10d that are holes for inserting the fork-shaped iron pieces 14, and each metal piece insertion portion 10d has It is provided at a position corresponding to the magnet fitting recess 20c. Since the attracting magnet 22 fitted in the magnet fitting recess 20c faces the iron piece 14 inserted in the metal piece insertion portion 10d in the direction of the optical axis C, in a state where the lens holding frame 20 is disposed on the movable frame 10, When the attracting magnet 22 attracts the iron piece 14, the lens holding frame 20 and the movable frame 10 attract each other. Further, since the magnetic attractive force of the attractive magnet 22 is stronger than the magnetic attractive force of the magnets 6a and 6b, it is ensured when the lens holding frame 20 is moved in the direction perpendicular to the optical axis C with respect to the movable frame 10. In addition, the lens holding frame 20 can be returned to a fixed position in the movable frame 10.

  As shown in FIG. 4, three ball receiving recesses 20 d are provided at positions corresponding to the ball mounting recesses 10 c (see FIG. 5) of the movable frame 10. In a state in which the lens holding frame 20 is disposed on the movable frame 10, the ball receiving recess 20d and the ball mounting recess 10c form a space large enough for the sphere 13 to enter. By inserting the sphere 13 into the space formed by the ball receiving recess 20d and the ball mounting recess 10c, the lens holding frame 20 is supported by the sphere 13 so as to be movable. Further, when three spheres 13 are connected in a plane orthogonal to the optical axis C, an isosceles triangle is formed, and the lens holding frame 20 is supported by the movable frame 10 at three points. Therefore, the lens holding frame 20 can be moved with respect to the movable frame 10 in a stable state.

  Further, as shown in FIG. 3, a back yoke 25 having a crescent shape when viewed from the optical axis C direction is provided on the side of the holding plate 21 of the lens holding frame 20 in the optical axis C direction. The back yoke 25 is in close contact with the magnets 6a, 6b, and 22 (see FIG. 9) of the lens holding frame 20 at the time of assembly.

  Next, the operation of the lens holding frame 20 will be described.

  If camera shake occurs when shooting with a device (for example, a camera) in which the lens driving device 1 is incorporated, the position of the optical axis C may change. In this case, a camera shake detection sensor such as a gyro sensor detects camera shake, and the control means (not shown) sends the drive signal of the lens holding frame 20 via the FPC 7 so that the position of the optical axis C is maintained at a predetermined position. Output to the coils 6c and 6d.

  Then, as shown in FIG. 9, the magnet 6a and the coil 6c generate a driving force F1 acting in the direction of a straight line connecting the magnet 6a, the coil 6c and the center O of the opening 20a (lens R), thereby holding the lens. The frame 20 is moved in the movable frame 10 in the direction in which the driving force F1 works. The magnet 6b and the coil 6d generate a driving force F2 that works in the direction of a straight line connecting the magnet 6b and the coil 6d and the center O, and move the lens holding frame 20 in the movable frame 10 in the direction in which the driving force F2 works. By the movement of the lens holding frame 20 in the direction in which the driving forces F1 and F2 work, the position of the optical axis C is moved to a fixed position, and camera shake is corrected.

  In the lens driving device 1 having such a configuration, only one coil 4a is used as a coil for moving the movable frame 10 in the direction of the optical axis C. Therefore, R is compared with the case where a plurality of coils are used. The area occupied by the department will be reduced. Therefore, useless space can be reduced, and downsizing of the apparatus can be realized. Further, in order to reduce the size of the entire apparatus, it is necessary to effectively use the space inside the apparatus. In order to effectively use the space inside the apparatus, the position where the coil 4a is arranged and the base portion 3 are required. It is necessary to consider the shape of Therefore, the position where the coil 4a is disposed is set away from the center of the base portion 3 in consideration of the lens R being disposed at the center of the base portion 3, so that the size of the lens R is increased. be able to. And since the shape of the base part 3 in the plane orthogonal to the optical axis C is made into a square as FIG. 7 shows, the coil 4a can be arrange | positioned along the one side 3z of the base part 3, and the coil 4a is enlarged. However, it can be arranged at a position away from the center of the base portion 3. Thus, since the shape of the base portion 3 is a quadrangular shape and the coil 4a is disposed in the vicinity of the one side 3z of the base portion 3, the space in the vicinity of the one side 3z of the base portion 3 can be effectively used. Compared with the case where the shape of the base part 3 is circular, it is not necessary to increase the size of the base part 3, which contributes to the downsizing of the apparatus. Since the end 4c of the coil 4a is bent and arranged so as to be separated from the corners 3x and 3y of the base 3, the coil 4a can be further increased in size and a desired large driving force can be obtained. Can be obtained.

  Further, instead of the magnets 4d, 4e, and 4f shown in FIG. 8, it is possible to make one bent magnet face the coil 4a. However, in this case, the direction of the magnetic field of the magnet is inclined at the end 4c of the coil 4a, and the direction of the magnetic field is not perpendicular to the surface of the coil 4a, so that the driving force cannot be sufficiently exerted. Therefore, since the magnets 4d, 4e, and 4f are opposed to the central portion 4b and the end portion 4c of the coil 4a by using the plurality of magnets 4d, 4e, and 4f, the direction of the magnetic field of the magnets 4d, 4e, and 4f is determined. Is perpendicular to the surface of the coil 4a, and the driving force can be sufficiently exerted.

  The base 3 includes a protrusion 3b that protrudes in the direction of the optical axis C from the vicinity of one side 3z of the base 3, and the protrusion 3b is fitted to fit the coil 4a in the direction of the optical axis C. A joint recess 3e is provided. Therefore, since the coil 4a can be easily fixed to the base portion 3 simply by fitting the coil 4a into the fitting recess 3e of the base portion 3, the apparatus can be easily assembled.

  The present invention is not limited to the embodiment described above.

  The lead 18 has a bent portion 18c that bends inward at a substantially central portion thereof, but the bent portion 18c may not be provided. Further, the lead 18 may be integrated with the FPC 5.

DESCRIPTION OF SYMBOLS 1 ... Lens drive device, 3 ... Base part, 3b ... Projection part, 3e ... Recessed part, 3x, 3y ... Corner part, 4 ... Focus adjustment drive part (drive part), 4a ... Coil, 4b ... Center part, 4c ... End Part, 4d, 4e, 4f ... magnet, 4g ... inside, 4x, 4y ... surface, 10 ... movable frame, 18 ... lead, 18d ... surface, C ... optical axis, R ... lens.

Claims (4)

In the lens driving device that moves the lens in the direction of the optical axis with respect to the base portion,
A movable frame supported on the base portion so as to be movable in the direction of the optical axis;
A drive unit that moves the movable frame in the direction of the optical axis by cooperation of a coil and a magnet,
The base portion has a quadrangular shape in a plane perpendicular to the optical axis,
The coil is wound in an air-core shape so that a winding axis is orthogonal to the optical axis,
The wound coil includes a central portion including the air-core portion, and end portions respectively positioned in the corner direction of the rectangular base portion on both sides of the central portion,
The central portion of the coil is fixed in the vicinity of one side of the base portion forming the quadrangular shape in a state where the winding axis is orthogonal to the optical axis.
Each of the end portions of the coil is bent so as to be separated from the corner portion of the base portion having the quadrangular shape and approach the optical axis in a state where the winding axis is orthogonal to the optical axis. And
The lens driving device according to claim 1, wherein the magnet faces each of the central portion and each end portion of the coil. Comprising a lead that transmits a drive signal to the coil for moving the movable frame in the direction of the optical axis;
In the central portion of the coil, an air-core-shaped space portion including the winding shaft is formed,
The lens driving device according to claim 1, wherein a part of the lead is disposed in the space portion. The base portion includes a protrusion protruding in the direction of the optical axis from the vicinity of the one side,
Struts are formed at both ends of the protrusion,
Each of the support columns is provided with a fitting portion for fitting the end of the coil.
The end of the coil fitted in the fitting part is inclined at a predetermined angle with respect to the one side so as to be separated from the corner as viewed from the optical axis direction. The lens driving device according to 1 or 2. On the outer surface of each column portion facing the outer periphery of the movable frame, a first receiving portion cut out in a concave shape is provided,
The outer peripheral surface of the movable frame facing the first receiving portion is provided with a second receiving portion cut into a concave shape,
The lens driving device according to claim 3, wherein at least one sphere is inserted between the first receiving portion and the second receiving portion.

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