CN111727405B

CN111727405B - Lens driving device, camera module, and camera mounting device

Info

Publication number: CN111727405B
Application number: CN201980013606.XA
Authority: CN
Inventors: 小沼真祐; 大坂智彦
Original assignee: Mitsumi Electric Co Ltd
Current assignee: Mitsumi Electric Co Ltd
Priority date: 2018-03-07
Filing date: 2019-03-04
Publication date: 2022-03-11
Anticipated expiration: 2039-03-04
Also published as: JP2019158906A; CN114545706A; WO2019172163A1; CN111727405A; TW201939115A; TWI802659B; JP7096484B2

Abstract

The invention provides a lens driving device, a camera module and a camera carrying device which can achieve miniaturization and light weight and can improve reliability. The lens driving device includes: a shake correction fixing section; a shake correction movable portion that is swingable within a plane orthogonal to the optical axis; a shake correction support portion that supports the shake correction movable portion in a state where the shake correction movable portion is spaced apart from the shake correction fixing portion in an optical axis direction; and a drive source that swings the shake correction movable portion. One of the shake correction fixing section and the shake correction movable section has a protruding section protruding in the optical axis direction. The other of the shake correction fixing section and the shake correction movable section has a flat section that abuts against the protruding section. The protruding portion and the flat portion slide relatively at the time of shake correction. The protruding portion is elastically displaceable in the optical axis direction.

Description

Lens driving device, camera module, and camera mounting device

Technical Field

The present invention relates to a lens driving device for shake correction, a camera module, and a camera-mounted device.

Background

In general, a small camera module is mounted in a portable terminal such as a smartphone. Such a camera module is applied with a lens driving device having an Auto Focus function (hereinafter referred to as an "AF function" for Auto Focus) for automatically focusing when an object is photographed and a shake correction function (hereinafter referred to as an "OIS function" for Optical Image Stabilization) for optically correcting shake (vibration) generated during photographing to reduce blur of an Image (for example, patent documents 1 and 2).

A lens driving device having an autofocus function and a shake correction function includes an autofocus driving unit (hereinafter referred to as "AF driving unit") for moving a lens unit in an optical axis direction and a shake correction driving unit (hereinafter referred to as "OIS driving unit") for swinging the lens unit in a plane orthogonal to the optical axis direction. In patent documents 1 and 2, a Voice Coil Motor (VCM) is applied to an AF driving unit and an OIS driving unit.

The OIS driving unit includes a shake correction movable unit (hereinafter referred to as "OIS movable unit") that swings in a plane orthogonal to the optical axis direction during shake correction. The OIS movable section is supported by a shake correction fixing section (hereinafter referred to as "OIS fixing section") via a shake correction support section (hereinafter referred to as "OIS support section"). In the lens driving device disclosed in patent document 1, the OIS supporting portion is formed by a suspension wire (japanese patent No. サスペンションワイヤー) extending in the optical axis direction, and the OIS movable portion is held in a state of being spaced apart from the OIS fixing portion in the optical axis direction.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-210550

Patent document 2: japanese patent laid-open publication No. 2012-177753

Disclosure of Invention

Problems to be solved by the invention

In recent years, in order to achieve reduction in size (thickness) and weight of camera-mounted equipment such as a smartphone, further reduction in size and weight has been demanded for a lens driving device. Accordingly, in the lens driving device of the wire support system as disclosed in patent document 1, there is a demand for thinning of the suspension wire and thinning of a member for fixing the suspension wire (hereinafter, referred to as "wire fixing member").

However, as the thinning of the suspension wire and the thinning of the wire fixing member progress, the rigidity thereof decreases, and therefore there is a concern that: the OIS movable unit is displaced in a plane orthogonal to the optical axis or inclined with respect to the optical axis due to a change in the posture of the lens driving device, a shift of the lens in focus, or the like, thereby degrading the performance of the AF function and the OIS function.

The invention aims to provide a lens driving device, a camera module and a camera mounting device which can achieve miniaturization and light weight and improve reliability.

Means for solving the problems

The present invention provides a lens driving device, comprising: a shake correction fixing section; a shake correction movable portion that is swingable within a plane orthogonal to the optical axis; a shake correction support portion that supports the shake correction movable portion in a state where the shake correction movable portion is spaced apart from the shake correction fixing portion in an optical axis direction; and a drive source that swings the shake correction movable portion, wherein one of the shake correction fixing portion and the shake correction movable portion has a protruding portion that protrudes in an optical axis direction, the other of the shake correction fixing portion and the shake correction movable portion has a flat portion that abuts against the protruding portion, the protruding portion and the flat portion relatively slide at the time of shake correction, and the protruding portion is elastically displaceable in the optical axis direction.

The present invention provides a camera module, comprising: the lens driving device described above; a lens unit attached to the shake correction movable unit; and an imaging unit that images the subject image formed by the lens unit.

The present invention provides a camera-mounted device which is an information apparatus or a conveying apparatus, the camera-mounted device including: the above-mentioned camera module; and an image processing unit that processes image information obtained by the camera module.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the lens driving device, the camera module, and the camera mounting device can be reduced in size and weight, and the reliability can be improved.

Drawings

Fig. 1A and 1B are diagrams showing a smartphone on which a camera module according to an embodiment of the present invention is mounted.

Fig. 2 is an external perspective view of the camera module.

Fig. 3 is an exploded perspective view of the camera module.

Fig. 4 is an exploded perspective view of the lens driving device.

Fig. 5 is an exploded perspective view of the lens driving device.

Fig. 6 is an exploded perspective view of the OIS movable section.

Fig. 7 is a sectional view of the OIS movable portion.

Fig. 8 is a bottom view of the OIS movable portion.

Fig. 9 is an exploded perspective view of the OIS fixing portion.

Fig. 10 is a plan view of the OIS fixing portion.

Fig. 11A and 11B are views showing a contact state between the protruding portion and the flat portion.

Fig. 12A and 12B are diagrams showing a displaced state of the protruding portion.

Fig. 13 is a view showing another example of the protrusion.

Fig. 14 is a view showing another example of the protrusion.

Fig. 15A and 15B are views showing the cantilever-type projecting portion.

Fig. 16A and 16B are views showing an automobile as a camera mounting device for mounting an in-vehicle camera module.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Fig. 1A and 1B are diagrams showing a smartphone M (camera-mounted device) on which a camera module a according to an embodiment of the present invention is mounted. Fig. 1A is a front view of the smartphone M, and fig. 1B is a rear view of the smartphone M.

The smartphone M is equipped with a camera module a as the back camera OC, for example. The camera module a has an AF function and an OIS function, and can automatically perform focusing when shooting a subject and optically correct shake (vibration) generated during shooting to capture an image without blurring.

Fig. 2 is an external perspective view of the camera module a. Fig. 3 is an exploded perspective view of the camera module a. As shown in fig. 2 and 3, in the present embodiment, an orthogonal coordinate system (X, Y, Z) is used for description. In the figures described later, the common orthogonal coordinate system (X, Y, Z) is also shown.

When the smartphone M is used to actually take an image, the camera module a is mounted so that the X direction is the up-down direction (or the left-right direction), the Y direction is the left-right direction (or the up-down direction), and the Z direction is the front-back direction. That is, the Z direction is the optical axis direction, the upper side in the figure is the optical axis direction light receiving side, and the lower side is the optical axis direction image forming side. The X-direction and the Y-direction orthogonal to the Z-axis are referred to as "orthogonal optical axis directions", and the XY-plane is referred to as "orthogonal optical axis plane".

As shown in fig. 2 and 3, the camera module a includes a lens driving device 1 that realizes an AF function and an OIS function, a lens unit 2 that houses a lens in a cylindrical lens barrel, an imaging unit (not shown) that images a subject image formed by the lens unit 2, a cover 3 that covers the entire camera module, and the like. In fig. 3, the lens unit 2 is omitted.

The cover 3 is a rectangular covered rectangular cylinder having a rectangular shape in plan view as viewed from the optical axis direction. In the present embodiment, the cover 3 has a square shape in plan view. The cover 3 has a substantially circular opening 3a on a light receiving side surface (hereinafter referred to as an "upper surface") in the optical axis direction. The lens portion 2 faces outward from the opening 3 a. The cover 3 is fixed to a base 21 (see fig. 9) of the OIS fixing section 20 of the lens driving apparatus 1 by bonding, for example.

The imaging unit (not shown) is disposed on the image forming side in the optical axis direction of the lens driving device 1. The image pickup unit (not shown) includes, for example, an image sensor substrate and an image pickup element mounted on the image sensor substrate. The imaging element is configured by, for example, a CCD (charge-coupled device) type image sensor, a CMOS (complementary metal oxide semiconductor) type image sensor, or the like. The image pickup device picks up an object image formed by the lens unit 2. The lens driving device 1 is mounted on an image sensor substrate (not shown), and is mechanically and electrically connected thereto. The control unit for controlling the driving of the lens driving device 1 may be provided on the image sensor substrate, or may be provided on a camera-mounted device (in the present embodiment, the smartphone M) on which the camera module a is mounted.

Fig. 4 and 5 are exploded perspective views of the lens driving device 1. Fig. 4 is an upper perspective view, and fig. 5 is a lower perspective view.

As shown in fig. 4 and 5, in the present embodiment, the lens driving device 1 includes an OIS movable portion 10, an OIS fixing portion 20, an OIS supporting portion 30, and the like. In the present embodiment, the driving source of the lens driving device 1 is constituted by a Voice Coil Motor (VCM).

The OIS movable portion 10 includes a drive magnet 122 (magnet for OIS, see fig. 6) constituting the voice coil motor for OIS, and is a portion which swings in the plane orthogonal to the optical axis during the shake correction. The OIS fixing section 20 includes an OIS coil 221 (see fig. 9) constituting an OIS voice coil motor, and is a section for supporting the OIS movable section 10 via the OIS supporting section 30. That is, the OIS driver of the lens driving device 1 employs a moving magnet type. The OIS movable section 10 includes an AF drive section having an AF movable section 11 and an AF fixed section 12 (see fig. 6).

The OIS movable section 10 is disposed on the light receiving side in the optical axis direction at a distance from the OIS fixing section 20, and is connected to the OIS fixing section 20 by the OIS supporting section 30. In the present embodiment, the OIS supporting section 30 is configured by 4 suspension wires (hereinafter referred to as "suspension wires 30") extending in the optical axis direction. The OIS support portion may be formed of a member other than the suspension wire 30.

One end (the end on the light receiving side in the optical axis direction, the upper end) of the suspension wire 30 is fixed to the OIS movable section 10 (in the present embodiment, to the AF supporting section 13 (see fig. 6)), and the other end (the end on the image forming side in the optical axis direction) of the suspension wire 30 is fixed to the OIS fixing section 20 (in the present embodiment, to the base 21 (see fig. 9)). The OIS movable section 10 is supported by the suspension wire 30 so as to be swingable in the plane orthogonal to the optical axis. Two suspension wires 30 out of the 4 suspension wires 30 are used as power supply paths for supplying power to the AF coil 112.

Fig. 6 is an exploded perspective view of the OIS movable section 10. Fig. 7 is a sectional view of the OIS movable section 10. Fig. 8 is a bottom view (view from the optical axis direction to the image side) of the OIS movable section 10. In fig. 7, a half section cut along the X direction or the Y direction through the center of the lens driving device 1 is shown.

As shown in fig. 6 to 8, in the present embodiment, the OIS movable section 10 includes an AF movable section 11, an AF fixed section 12,

AF support sections

13 and 14, and the like. The AF movable portion 11 is disposed radially inward of the AF fixing portion 12 with a space therebetween, and is connected to the AF fixing portion 12 via

AF support portions

13 and 14.

The AF movable portion 11 has an AF coil 112 constituting an AF voice coil motor, and moves in the optical axis direction during focusing. The AF fixing portion 12 includes a driving magnet 122(AF magnet) constituting the voice coil motor for AF, and is a portion for supporting the AF movable portion 11 via the

AF supporting portions

13 and 14. That is, the AF drive unit of the lens drive device 1 adopts a moving coil type.

The AF movable portion 11 is disposed at a distance from the AF fixing portion 12, and is connected to the AF fixing portion 12 via

AF supporting portions

13 and 14. In the present embodiment, the AF movable part 11 is disposed at a radial distance from the AF fixed part 12. The AF supporting portion 13 is an upper elastic supporting member that supports the AF movable portion 11 on the light receiving side (upper side) in the optical axis direction with respect to the AF fixing portion 12. In the present embodiment, the AF supporting portion 13 is composed of two plate springs 131 and 132 (hereinafter, referred to as "

upper springs

131 and 132"). The AF supporting portion 14 is a lower elastic supporting member that supports the AF movable portion 11 on the image side (lower side) in the optical axis direction with respect to the AF fixing portion 12. In the present embodiment, the AF support portion 14 is composed of two leaf springs 141 and 142 (hereinafter, referred to as "

lower springs

141 and 142").

In the present embodiment, the OIS movable section 10 includes the sliding section 15 on the image side in the optical axis direction, and the sliding section 15 is disposed so as to partially contact the OIS fixing section 20 and slides relative to the OIS fixing section 20 during shake correction.

As shown in fig. 6 to 8, in the OIS movable part 10, the AF movable part 11 includes a lens holder 111 and an AF coil 112.

The lens holder 111 is a member that holds the lens unit 2 (see fig. 2). The lens holder 111 has a cylindrical lens housing section 111a, and an upper flange 111b and a lower flange 111c that protrude radially outward from the lens housing section 111 a. That is, the lens holder 111 has a bobbin (Japanese: ボビン) configuration. The upper flange 111b and the lower flange 111c have a substantially octagonal shape in plan view.

The AF coil 112 is wound around a portion (hereinafter referred to as a "coil winding portion") sandwiched between the upper flange 111b and the lower flange 111 c. The coil winding portion (reference numeral omitted) has a substantially regular octagonal shape in plan view. Accordingly, the load acting on the coil winding portion when the AF coil 112 is directly wound is uniform, and the strength of the coil winding portion is substantially uniform with respect to the center, so that the opening of the lens housing portion 111a can be prevented from being deformed, and the roundness can be maintained.

The lens portion (see fig. 2) is fixed to the lens housing portion 111a by, for example, adhesion. Preferably, the lens housing section 111a has a groove (not shown) on the inner peripheral surface thereof to which an adhesive is applied. In the method of attaching the lens unit 2 to the lens housing section 111a by screwing, there is a possibility that the suspension wire 30 supporting the OIS movable section 10 may be damaged. In contrast, in the present embodiment, the lens unit 2 is fixed to the inner peripheral surface of the lens housing portion 111a by adhesion, and therefore the suspension wire 30 can be prevented from being damaged when the lens unit 2 is attached. Further, when the inner peripheral surface of the lens housing section 111a has a groove, the groove holds an appropriate amount of the adhesive, and thus the adhesive strength between the lens holder 111 and the lens section 2 is improved.

The lens holder 111 has an upper spring fixing portion 111d for fixing the AF support portion 13 on the upper outer peripheral edge of the lens housing portion 111 a. In the present embodiment, the upper spring fixing portions 111d are provided to face each other in the X direction. The lens holder 111 has a lower spring fixing portion 111e for fixing the AF support portion 14 on a surface (hereinafter referred to as "lower surface" or "bottom surface") on the optical axis direction of the lower flange 111c forming an image side. In the present embodiment, the lower spring fixing portions 111e are provided to face each other in the Y direction.

The lens holder 111 has a binding portion (not shown) that binds an end portion of the AF coil 112.

In the present embodiment, the lens holder 111 is formed of a molding material containing Polyarylate (PAR) or a PAR alloy in which a plurality of resin materials containing PAR are mixed. In particular, the PAR alloy is preferably a polymer alloy comprising PAR and Polycarbonate (PC) (PAR/PC). Thus, the fusion strength is improved as compared with a conventional molding material (for example, Liquid Crystal Polymer (LCP)), and therefore, even if the lens holder 111 is made thin, toughness and impact resistance can be ensured, and therefore, the outer dimensions of the lens driving device 1 can be reduced, and downsizing and weight reduction can be achieved.

Further, it is preferable that the lens holder 111 is formed by injection molding of a multi-gate. In this case, the gate diameter is preferably 0.3mm or more. This makes it possible to realize thin-wall molding and to prevent the occurrence of sink marks (Japanese patent: ヒケ) even when PAR or a PAR alloy is used as a molding material because of its good fluidity during molding.

The shaped material comprising PAR or a PAR alloy has an electrical conductivity, in particular a volume resistivity of preferably 10⁹Ω·cm～10¹¹Omega cm. For example, electrical conductivity can be easily imparted by mixing carbon nanotubes into conventional PAR or PAR alloy. At this timeAppropriate conductivity can be imparted by adjusting the content of the carbon nanotubes. This can suppress the electrification of the lens holder 111, and thus can prevent the generation of static electricity.

The AF coil 112 is an air-core coil that is energized during focusing, and is wound around the outer peripheral surface of a coil winding portion (reference numeral omitted) of the lens holder 111. Both ends of the AF coil 112 are respectively bound to binding portions (not shown) of the lens holder 111. The AF coil 112 is energized through the AF support 13 (upper springs 131 and 132) or the AF support 14 (lower springs 141 and 142). The current applied to the AF coil 112 is controlled by a drive control unit provided on the image sensor substrate.

As shown in fig. 6 to 8, in the OIS movable section 10, the AF fixed section 12 includes a magnet holder 121 and a driving magnet 122.

The magnet holder 121 is a member that holds the driving magnet 122. In the present embodiment, the magnet holder 121 is formed of a frame having a substantially octagonal shape in plan view. The magnet holder 121 has an opening 121a formed by cutting out a portion corresponding to the lens holder 111. In the present embodiment, the magnet holder 121 has a magnet holding portion 121b for holding the driving magnet 122 on the inner peripheral surface at a position corresponding to the four corners of the lens driving device 1. The inner surface of the magnet holding portion 121b serves as an adhesive surface to which the driving magnet 122 is adhered.

The magnet holding portion 121b has an adhesive surface parallel to the optical axis direction, and an end portion on the image side in the optical axis direction (an end portion on the OIS fixing portion 20 side in the optical axis direction) is open. This is because the driving magnet 122 is also used as an OIS magnet, and it is preferable that there is no inclusion with the OIS coil 221 (see fig. 9) disposed in the OIS fixing portion 20 in terms of magnetic properties. That is, the driving magnet 122 is not physically fixed so as not to fall off by the shape of the magnet holding portion 121b, but is fixed only by the adhesive force of the adhesive.

The outer peripheral surface of the magnet holder 121 at the positions corresponding to the four corners of the lens driving device 1 is linearly cut off. The suspension wire 30 is disposed in this portion. In the magnet holder 121, the portion where the suspension wire 30 is disposed may be formed so as to be recessed in an arc shape radially inward. This can avoid interference between the suspension wire 30 and the magnet holder 121 when the OIS movable section 10 swings, without increasing the outer shape of the lens driving device 1.

The magnet holder 121 has an upper spring fixing portion 121d for fixing the AF supporting portion 13 on the upper surface. In the present embodiment, upper spring fixing portions 121d are provided on the upper surface of the magnet holder 121 at positions corresponding to the four corners of the lens driving device 1. The magnet holder 121 has a lower spring fixing portion (not shown) for fixing the AF support portion 14 on the lower surface. In the present embodiment, as in the case of the upper spring fixing portion 121d, lower spring fixing portions (not shown) are provided at positions corresponding to four corners of the lens driving device 1. The corner of the upper spring fixing portion 121d is formed to be recessed more toward the optical axis direction imaging side than the face to which the AF support portion 13 is attached, so that a gap is formed when the AF support portion 13 is attached.

In the present embodiment, the magnet holder 121 is formed of a liquid crystal polymer. The magnet holder 121 may be formed of a molding material containing PAR or PAR alloy, as in the lens holder 111, but is preferably formed of a liquid crystal polymer having excellent heat resistance. Since the magnet holder 121 has high heat resistance, the

AF supporters

13 and 14 and the like can be easily welded (japanese: yagi 12369. The magnet holder 121 is formed by injection molding using a mold, for example.

In the present embodiment, the driving magnet 122 is composed of 4 rectangular columnar magnets. The driving magnet 122 has a substantially isosceles trapezoidal shape in a plan view. This makes it possible to effectively use the space at the corner of the magnet holder 121 (the magnet holder 121 b). The drive magnet 122 is magnetized so as to form a magnetic field that radially crosses the AF coil 112. In the present embodiment, the inner circumferential side of the driving magnet 122 is magnetized to the N-pole, and the outer circumferential side of the driving magnet 122 is magnetized to the S-pole. Further, the surface of the driving magnet 122 is covered with a metal film such as a Ni plating film, and corrosion resistance is improved.

In the present embodiment, the driving magnet 122 is fixed to the magnet holder 121b of the magnet holder 121 by adhesion. As the adhesive, for example, an epoxy resin-based thermosetting adhesive or an ultraviolet curing adhesive is used. The surface of the drive magnet 122 that contacts the magnet holding portion 121b (in the present embodiment, the side surface and the upper surface except the surface exposed inside) serves as an adhesive surface.

The driving magnet 122 and the AF coil 112 constitute an AF voice coil motor. In the present embodiment, the driving magnet 122 is used as both the AF magnet and the OIS magnet. Further, a yoke may be provided on the circumferential surface of the driving magnet 122.

As shown in fig. 6 to 8, in the OIS movable section 10, the AF supporting section 13 (upper springs 131 and 132) elastically supports the AF movable section 11 (lens holder 111) on the light receiving side in the optical axis direction with respect to the AF fixing section 12 (magnet holder 121). The

upper springs

131, 132 are formed of, for example, titanium copper, nickel copper, stainless steel, or the like.

The

upper springs

131 and 132 have a rectangular shape as a whole in plan view, that is, the same shape as the magnet holder 121. The

upper springs

131 and 132 are disposed on the magnet holder 121 so as not to contact each other. The

upper springs

131 and 132 are formed by etching a single metal plate, for example.

The

upper springs

131 and 132 include lens

holder fixing portions

131a and 132a fixed to the lens holder 111, magnet

holder fixing portions

131b and 132b fixed to the magnet holder 121, and

arm portions

131c and 132c connecting the lens

holder fixing portions

131a and 132a and the magnet

holder fixing portions

131b and 132b, respectively. The

arm portions

131c and 132c are formed to be curved and elastically deformed when the AF movable portion 11 moves in the optical axis direction.

The

upper springs

131 and 132 have

wire connection portions

131d and 132d connected to the suspension wire 30, respectively. The

wire connecting portions

131d, 132d are connected to the magnet

holder fixing portions

131b, 132b via connecting

portions

131e, 132e extending in a zigzag shape.

In the present embodiment, the

upper springs

131 and 132 are electrically connected to a binding portion (not shown) of the lens holder 111, and the AF coil 112 is energized through the

upper springs

131 and 132.

As shown in fig. 6 to 8, in the OIS movable section 10, the AF supporting section 14 (lower springs 141 and 142) elastically supports the AF movable section 11 (lens holder 111) on the image side in the optical axis direction with respect to the AF fixing section 12 (magnet holder 121). The lower springs 141, 142 are formed of, for example, titanium copper, nickel copper, stainless steel, or the like.

The

lower springs

141 and 142 have a rectangular shape as a whole in plan view, that is, the same shape as the magnet holder 121. The

lower springs

141 and 142 are disposed on the magnet holder 121 so as not to contact each other. The

lower springs

141 and 142 are formed by etching a single metal plate, for example.

The

lower springs

141 and 142 include lens

holder fixing portions

141a and 142a fixed to the lens holder 111, magnet

holder fixing portions

141b and 142b fixed to the magnet holder 121, and

arm portions

141c and 142c connecting the lens

holder fixing portions

141a and 142a and the magnet

holder fixing portions

141b and 142b, respectively. The

arm portions

141c and 142c are formed to be curved and elastically deformed when the AF movable portion 11 moves in the optical axis direction.

In the present embodiment, as shown in fig. 6 to 8, in the OIS movable section 10, the sliding section 15 is constituted by the holding member 151, the spacer 152, and the spherical body 153. The sliding portion 15 is disposed closest to the optical axis direction image side of the OIS movable portion 10, and abuts against the OIS fixing portion 20.

In the present embodiment, the spherical body 153 corresponds to the protruding portion of the present invention. That is, the spherical body 153 protrudes toward the image forming side in the optical axis direction and abuts against the sliding plate 23 (see fig. 9, flat portion) of the OIS fixing section 20. By using the spherical body 153 as the projection, the contact area is small due to the point contact with the sliding plate 23, and therefore, the slidability at the time of shake correction can be ensured. Further, the ball 153 slides on the slide plate 23 at the time of shake correction, instead of rolling.

The holding member 151 is a frame having a substantially rectangular shape in plan view, and is bonded to the spacer 152. The holding member 151 is formed of a resin material such as Polycarbonate (PC).

The holding member 151 has a thick portion 151b and a thin portion 151 a. In the present embodiment, the holding member 151 has a thin portion 151a at substantially the center in the longitudinal direction of the four sides. The holding member 151 has a ball housing portion 151c that houses the ball 153 on the bottom surface side of the thin portion 151 a. The ball receiving portion 151c has a recess (reference numeral omitted) at the center corresponding to the shape of the ball 153. The ball 153 is disposed in the recess.

The thin portion 151a is thinner than the thick portion 151b, and is formed to be elastically deformable in the optical axis direction. In the present embodiment, the upper surface of the thin portion 151a is formed to be concave, and when receiving a force in the optical axis direction, it bends toward the light receiving side in the optical axis direction to release the stress. That is, in the sliding portion 15, the holding member 151 has a beam structure of a both-end support type. A ball 153 as a protruding portion is disposed on the thin portion 151a as a beam portion. The recess of the upper surface of the thin portion 151a is preferably larger than the gap formed between the holding member 151 and the sliding plate 23 (see fig. 12A).

The spacer 152 is a frame having a substantially rectangular shape in plan view, like the holding member 151, and is bonded to the bottom surface of the magnet holder 121. The spacer 152 is a rigid body formed of a metal material such as a copper alloy, for example.

The ball 153 is formed of a metal material such as zirconia. The ball 153 is disposed in the ball receiving portion 151c of the holding member 151. The sphere 153 is interposed between the OIS movable portion 10 and the OIS fixing portion 20. When the OIS movable section 10 and the OIS fixed section 20 are connected by the suspension wire 30, the ball 153 is biased toward the OIS fixed section 20 (the sliding plate 23). Thereby, the spherical body 153 reliably abuts on the OIS fixing section 20.

In the present embodiment, the OIS movable section 10 is supported by 4 spheres 153. Thereby, the OIS movable section 10 is held in a stable posture with respect to the OIS fixing section 20. From the viewpoint of stabilizing the posture of the OIS movable section 10, the number of spheres 153 (protruding sections) is preferably 3 or more, that is, the OIS movable section 10 is supported at 3 or more points.

Fig. 9 is an exploded perspective view of the OIS fixing section 20. Fig. 10 is a plan view of the OIS fixing portion 20.

As shown in fig. 9 and 10, the OIS fixing section 20 includes a base 21, a coil substrate 22, a slide plate 23, and the like.

The base 21 is a support member that supports the coil substrate 22 and the slide plate 23. The base 21 is a rectangular member in plan view, and has a substantially circular opening 21a at the center. The base 21 is embedded with a terminal fitting 211. The terminal fitting 211 is integrally formed with the base 21 by insert molding, for example. In the present embodiment, the terminal fittings 211 are exposed from four corners of the base 21. The terminal fitting 211 is welded to the power supply terminal (not shown) of the coil substrate 22 and the suspension wire 30, and is physically and electrically connected thereto.

In the present embodiment, the base 21 is formed of a molding material containing Polyarylate (PAR) or a PAR alloy (for example, PAR/PC) in which a plurality of resin materials containing PAR are mixed, similarly to the lens holder 111. This improves the fusion strength, and therefore, even if the base 21 is thinned, toughness and impact resistance can be ensured. Therefore, the outer dimensions of the lens driving device 1 can be reduced, and the size and the back can be reduced.

Further, it is preferable that the pedestal 21 is formed by injection molding of a multi-gate. In this case, the gate diameter is preferably 0.3mm or more. This makes it possible to realize thin-wall molding and to prevent sink marks even when PAR or a PAR alloy is used as a molding material because of its good fluidity during molding.

The shaped material comprising PAR or a PAR alloy has an electrical conductivity, in particular a volume resistivity of preferably 10⁹Ω·cm～10¹¹Omega cm. For example, electrical conductivity can be imparted by mixing carbon nanotubes into conventional PAR or PAR alloy. In this case, appropriate conductivity can be provided by adjusting the content of the carbon nanotubes. This can suppress the electrification of the base 21, and thus can prevent the generation of static electricity.

The base 21 has a coil substrate fixing portion 21b on which the coil substrate 22 is disposed and a sliding plate fixing portion 21c on which the sliding plate 23 is disposed, at the periphery of the opening 21 a. The coil substrate fixing portion 21b is formed on the inner peripheral side of the sliding plate fixing portion 21c so as to be recessed from the sliding plate fixing portion 21 c. The upper surface of the sliding plate 23 disposed on the sliding plate fixing portion 21c is positioned closer to the light receiving side in the optical axis direction than the upper surface of the coil substrate 22 disposed on the coil substrate fixing portion 21 b. Thereby, a gap is reliably formed between the coil substrate 22 and the OIS movable section 10 (holding member 151).

As shown in fig. 9 and 10, in the OIS fixing section 20, the coil substrate 22 is a rectangular substrate in plan view like the base 21, and has a circular opening 22a at the center. The coil substrate 22 is, for example, a multilayer printed wiring board in which unit layers including conductor layers and insulating layers (not shown) are laminated in a plurality of layers. The coil substrate 22 is integrally formed with, for example, the OIS coil 221, an external terminal (not shown), and a conductor pattern (not shown) including a power supply line connecting the external terminal and the OIS coil 221.

In the OIS fixing section 20, the sliding plate 23 is a frame having a substantially rectangular shape in plan view, as in the holding member 151. The slide plate 23 is formed of a metal material such as a copper alloy. In the present embodiment, the sliding plate 23 corresponds to the flat portion of the present invention. That is, the upper surface (sliding surface) of the sliding plate 23 is a flat surface and abuts against the ball 153. The substantially center 23a in the longitudinal direction of the four sides of the sliding plate 23 serves as an abutting portion with which the spherical body 153 abuts. The width of the slide plate 23 can be appropriately set according to the swing range of the OIS movable portion 10.

In the present embodiment, the sliding surface of the sliding plate 23 is subjected to low friction treatment. For the low friction treatment, for example, a Ni plating treatment for dispersing PTFE (Polytetrafluoroethylene) can be applied. This can reduce the frictional force generated when the ball 153 slides on the sliding plate 23, and thus can ensure the slidability during the shake correction.

In the present embodiment, the base 21, the coil substrate 22, and the slide plate 23 are bonded together by an elastic epoxy resin material. Since the base 21, the coil substrate 22, and the sliding plate 23 are integrated by adhesion, the mechanical strength of the OIS fixing portion 20 is improved, and thus the base 21, the coil substrate 22, and the sliding plate 23 can be thinned while ensuring desired drop impact resistance.

In the lens driving device 1, one end of the suspension wire 30 is physically and electrically connected to the

wire connection portions

131d and 132d of the

upper springs

131 and 132, respectively. The other end of the suspension wire 30 is physically and electrically connected to the terminal fitting 211 (the portion exposed from the cutout portions at the four corners) of the base 21. When the OIS movable section 10 and the OIS fixed section 20 are connected by the suspension wire 30, the ball 153 is biased toward the OIS fixed section 20 (the sliding plate 23).

The lens driving device 1 may further include a Z-position detecting unit that detects a position of the AF movable unit 11 in the optical axis direction and/or an XY-position detecting unit that detects a position of the OIS movable unit 10 in a plane orthogonal to the optical axis. For example, the Z-position detecting unit and the XY-position detecting unit may be constituted by a position detecting magnet and a hall element, respectively. The hall element is disposed opposite to the position detection magnet.

In the case of the Z position detection unit, for example, a detection magnet is disposed on the AF movable unit 11 (e.g., the lens holder 111), and a hall element is disposed on the AF fixed unit 12 (e.g., the magnet holder 121). When the AF movable portion 11 moves in the optical axis direction, the magnetic field based on the position detection magnet changes. The position of the AF movable portion 11 in the optical axis direction is detected by detecting the change in the magnetic field using the hall element. Note that a control IC incorporating a hall element may be disposed in the AF fixing portion 12, and the current applied to the AF coil 112 may be controlled by the control IC.

The XY position detecting unit has two sets of position detecting magnets and Hall elements. As the position detection magnet, the drive magnet 122 may be used. In the XY position detecting unit, for example, a detecting magnet is disposed in the OIS moving unit 10 (e.g., the magnet holder 121), and a hall element is disposed in the OIS fixing unit 20 (e.g., the coil substrate 22). When the OIS movable portion 10 moves in the plane orthogonal to the optical axis, the magnetic field generated by the position detection magnet changes. The position of the OIS movable section 10 in the plane orthogonal to the optical axis is detected by detecting the change in the magnetic field using the two hall elements.

Since the response performance is improved by performing the closed-loop control based on the hall output, the AF operation or the OIS operation can be speeded up.

When the lens driving device 1 performs the shake correction, the OIS coil 221 is energized. Specifically, the OIS driver controls the current applied to the OIS coil 221 based on a detection signal from a shake detector (not shown, for example, a gyro sensor) so that the shake of the camera module a is cancelled.

When the OIS coil 221 is energized, a lorentz force (fleming's left-hand rule) is generated in the OIS coil 221 by the interaction between the magnetic field of the drive magnet 122 and the current flowing through the OIS coil 221. The direction of the lorentz force is a direction orthogonal to the magnetic field direction (Z direction) and the current direction at the long side portion of the OIS coil 221. Since the OIS coil 221 is fixed, a reaction force acts on the driving magnet 122. This reaction force becomes a driving force of the OIS voice coil motor, and the OIS movable portion 10 having the driving magnet 122 swings in the XY plane to perform shake correction. At this time, the ball 153 slides on the slide plate 23.

When the lens driving device 1 performs autofocus, the AF coil 112 is energized. When the AF coil 112 is energized, a lorentz force is generated in the AF coil 112 by interaction between the magnetic field of the driving magnet 122 and the current flowing through the AF coil 112. The direction of the lorentz force is a direction (Z direction) orthogonal to the direction of the magnetic field and the direction of the current flowing through the AF coil 112, respectively. Since the driving magnet 122 is fixed, a reaction force acts on the AF coil 112. This reaction force becomes a driving force of the voice coil motor for AF, and the AF movable portion 11 having the coil 112 for AF moves in the optical axis direction to perform focusing.

When no current is supplied to the AF movable unit 11 without focusing, the AF movable unit is suspended between the infinity position and the macro position by the

upper springs

131 and 132 and the lower springs 141 and 142 (neutral point). That is, in the OIS movable section 10, the AF movable section 11 (lens holder 111) is elastically supported by the

upper springs

131 and 132 and the

lower springs

141 and 142 so as to be displaceable on both sides in the Z direction in a state of being positioned with respect to the AF fixing section 12 (magnet holder 121).

Fig. 11A and 11B are views showing a contact state between the spherical body 153 (protruding portion) and the slide plate 23 (flat portion). Fig. 11A shows a cross section passing through the widthwise center of one side of the holding member 151. Fig. 11B shows the dotted line portion of fig. 11A in an enlarged manner.

As shown in fig. 11A and 11B, in the lens driving device 1, since the spherical body 153 is biased toward the OIS fixing section 20, the spherical body 153 abuts against the slide plate 23. Since the ball 153 protrudes to the image forming side in the optical axis direction from the bottom surface of the holding member 151, a gap is formed between the bottom surface of the holding member 151 and the upper surface of the sliding plate 23. When the OIS movable section 10 swings in the plane orthogonal to the optical axis during the shake correction, the ball 153 slides on the slide plate 23.

In the present embodiment, the surface of the slide plate 23 is subjected to a low friction treatment. Further, the contact area is extremely small because the ball 153 and the slide plate 23 are in contact with each other. Therefore, the OIS movable portion 10 partially abuts against the OIS fixing portion 20, but does not interfere with the oscillation of the OIS movable portion 10.

Here, as shown in fig. 12A, when a force in the optical axis direction acts on the lens driving device 1 due to a drop impact, the force is concentrated on the spherical body 153. Accordingly, the thin portion 151a of the holding member 151 is bent, and the ball 153 is displaced in the optical axis direction to the light receiving side (see fig. 12B). On the other hand, when the force in the optical axis direction is released, the ball 153 returns to the original state (see fig. 12A). That is, the ball 153 can be elastically displaced in the optical axis direction.

In this way, the force in the optical axis direction due to the falling impact is absorbed by the sliding portion 15, and therefore the force transmitted to the suspension wire 30, the

AF support portions

13 and 14, and the like is reduced. Therefore, the lens driving device 1 can be prevented from being damaged by a drop impact, and the suspension wire 30 can be reduced in diameter and the

AF support portions

13 and 14 can be reduced in thickness.

In this manner, the lens driving device 1 includes: an OIS fixing section 20 (shake correction fixing section); an OIS movable section 10 (shake correction movable section) which is swingable in a plane orthogonal to the optical axis; a suspension wire 30 (support portion for shake correction) that supports the OIS movable portion 10 in a state in which the OIS movable portion 10 is spaced apart from the OIS fixing portion 20 in the optical axis direction; and a voice coil motor (drive source) that swings the OIS movable section 10.

In the lens driving device 1, the OIS movable portion 10 (one of the shake correction fixed portion and the shake correction movable portion) has a spherical body 153 (protruding portion) protruding in the optical axis direction. The OIS fixing section (the other of the shake correction fixing section and the shake correction movable section) has a sliding plate 23 (a flat section) which abuts against the ball 153. The ball 153 and the sliding plate 23 slide relatively at the time of shake correction. Also, the spherical body 153 can be elastically displaced in the optical axis direction.

According to the lens driving device 1, the spherical body 153 is interposed between the OIS movable section 10 and the OIS fixing section 20, and the OIS movable section 10 is supported by the spherical body 153, so that the OIS movable section 10 is held in a stable posture. Accordingly, even if the rigidity of the suspension wires 30 is reduced by thinning the wires and thinning the AF support portions 13 and 14 (wire fixing members), the performance of the AF function and the OIS function can be prevented from being reduced by displacement of the OIS movable portion 10 in the plane orthogonal to the optical axis or inclination with respect to the optical axis.

Further, since the ball 153 is held so as to be elastically displaceable, the force acting upon the falling impact is absorbed by the sliding portion 15, and therefore, the components of the lens driving device 1 can also be prevented from being damaged.

Therefore, according to the lens driving device 1, it is possible to achieve downsizing and weight reduction, and to improve reliability.

The invention made by the present inventors has been specifically described above based on the embodiments, but the invention is not limited to the above embodiments and can be modified within a range not departing from the gist thereof.

For example, although the embodiment shows the holding member 151 being flexed to absorb a drop impact, an urging member that exerts a restoring force when the ball 153 is displaced in the optical axis direction may be interposed between the holding member 151 and the ball 153. For example, the plate spring 154 (see fig. 13) may be provided as the biasing member. Both ends of the plate spring 154 are fixed by the holding member 151, and therefore, when receiving a force in the optical axis direction from the spherical body 153, they are deflected.

Further, a coil compression spring may be disposed as the urging member. In the case of applying a helical compression spring, there may be no gap between the holding member 151 and the spacer 152.

For example, in the embodiment, the case where the holding member 151 has a beam structure of a both-end support type is described, but as shown in fig. 14, a cantilever beam structure may be applied. In this case, the holding member 151 may be constituted by a plurality of members (see fig. 15A), or the holding member 151 may be constituted by one member (see fig. 15B).

Further, the holding member 151 may be integrally formed with a projection. In this case, the tip end portion of the projection (the portion abutting against the slide plate 23) is preferably spherical. Thereby, the slidability of the OIS movable portion 10 can be ensured as in the case where the spherical body 153 is arranged.

In the embodiment, the sliding plate 23 may be omitted, and a part of the base 21 or the coil substrate 22 may function as a flat portion. However, since the flat portion is preferably a rigid body such as a metal, it is preferable to provide the flat portion independently of the chassis 21 and the coil substrate 22.

In the embodiment, the case where the protruding portion is provided on the OIS movable portion 10 and the flat portion is provided on the OIS fixing portion 20 is described, but the flat portion may be provided on the OIS movable portion 10 and the protruding portion may be provided on the OIS fixing portion 20. Further, not only the flat portion but also the protruding portion may be subjected to the low friction treatment.

In the embodiment, the smartphone M as a portable terminal with a camera is described as an example of a camera-mounted device provided with the camera module a, but the present invention is applicable to a camera-mounted device provided with a camera module and an image processing unit that processes image information obtained by the camera module. The camera-mounted device includes an information apparatus and a conveyance apparatus. The information equipment includes, for example, a camera-equipped mobile phone, a notebook computer, a tablet terminal, a portable game machine, a web camera, and a camera-equipped in-vehicle device (e.g., a rear monitor device, a drive recorder device). In addition, the transport apparatus includes, for example, an automobile.

Fig. 16A and 16B are views showing a Vehicle V as a Camera mounting device on which a Vehicle-mounted Camera module VC (Vehicle Camera) is mounted. Fig. 16A is a front view of the automobile V, and fig. 16B is a rear perspective view of the automobile V. The vehicle V is equipped with the camera module a described in the embodiment as the in-vehicle camera module VC. As shown in fig. 16A and 16B, the vehicle-mounted camera module VC is attached to, for example, a front windshield facing forward or a tailgate facing rearward. The in-vehicle camera module VC is used for rear monitor, automobile data recorder, collision avoidance control, automatic driving control, and the like.

The configurations of the AF coil, AF magnet, OIS coil, and OIS magnet are not limited to those described in the embodiments. For example, the driving magnet that also functions as the AF magnet and the OIS magnet may have a rectangular parallelepiped shape and be disposed around the AF coil so that the magnetization direction coincides with the radial direction. Further, the flat AF coil may be disposed around the lens portion so that the coil surface is parallel to the optical axis direction, and the rectangular parallelepiped driving magnet may be disposed so that the magnetization direction intersects the coil surface of the AF coil.

In the embodiment, the description has been given of the case where the driving magnet is used as both the AF magnet and the OIS magnet in the lens driving device having the OIS function and the AF function, but the AF magnet and the OIS magnet may be provided separately. In addition, the present invention can be applied to a lens driving apparatus having only an OIS function. The present invention can also be applied to a lens driving device including a driving source (e.g., an ultrasonic motor) other than the VCM.

In the embodiment, the lens driving device 1 having the so-called optical shake correction function in which the lens unit 2 is disposed in the OIS movable unit 10 and the imaging unit is disposed in the OIS fixed unit 20, and shake correction is performed by swinging the lens unit 2 with respect to the imaging unit has been described, but the present invention can also be applied to a lens driving device having the so-called sensor shift shake correction function in which the lens unit is disposed in the OIS fixed unit and the imaging unit is disposed in the OIS movable unit, and shake correction is performed by swinging the imaging unit with respect to the lens unit.

All inventive aspects of the embodiments disclosed herein are exemplary and should not be considered as limiting the invention. The scope of the present invention is defined by the claims rather than the description above, and all modifications within the meaning and range equivalent to the claims are intended to be included therein.

The disclosure of the specification, drawings and abstract contained in japanese application No. 2018-040489, filed 3/7/2018 are all incorporated into the present application.

Description of the reference numerals

1. A lens driving device; 2. a lens section; 3. a cover; 10. an OIS movable section (shake correction movable section); 11. an AF movable part; 12. an AF fixing section; 13. 14, an AF support part; 15. a sliding part; 20. an OIS fixing section (shake correction fixing section); 21. a base; 22. a coil substrate; 23. a sliding plate (flat portion); 30. a support for OIS; 111. a lens holder; 112. a coil for AF; 121. a magnet holder; 122. a drive magnet; 151. a holding member; 152. a spacer; 153. a sphere (projection); 221. a coil for OIS; m, a smart phone; A. a camera module.

Claims

1. A lens driving device includes: a shake correction fixing section; a shake correction movable portion that is swingable within a plane orthogonal to the optical axis; a shake correction support portion that supports the shake correction movable portion in a state where the shake correction movable portion is spaced apart from the shake correction fixing portion in an optical axis direction; and a drive source that swings the shake correction movable portion, the lens drive device being characterized in that,

one of the shake correction fixing section and the shake correction movable section has a protruding section protruding in the optical axis direction,

the other of the shake correction fixed portion and the shake correction movable portion has a flat portion abutting against the protruding portion,

the protruding portion and the flat portion slide relatively at the time of shake correction,

the protruding portion is elastically displaceable in the optical axis direction when a force in the optical axis direction acts on the lens driving device due to a falling impact.

2. The lens driving device according to claim 1,

the protruding portion is urged against the flat portion.

3. The lens driving device according to claim 1 or 2,

the sliding surface of at least one of the protruding portion and the flat portion is subjected to a low friction treatment.

4. The lens driving device according to claim 3,

the low friction treatment is a Ni plating treatment in which PTFE particles are dispersed.

5. The lens driving device according to claim 1,

the lens driving device comprises a holding member for holding the projection,

the holding member has a beam portion supported at both ends or a cantilevered beam portion,

the protruding portion is disposed on the beam portion.

6. The lens driving device according to claim 1,

the lens driving device includes:

a holding member that holds the protruding portion; and

a biasing member interposed between the holding member and the protruding portion,

the urging member exerts a restoring force when the protruding portion is displaced in the optical axis direction.

7. The lens driving device according to claim 6,

the urging member is a plate spring mounted to the holding member in a supported or cantilevered manner at both ends.

8. The lens driving device according to claim 6,

the urging member is a helical compression spring.

9. The lens driving device according to claim 1,

the protruding portion has a spherical shape and is in point contact with the flat portion.

10. The lens driving device according to claim 9,

the projection is constituted by a spherical member.

11. The lens driving device according to claim 1,

the drive source includes:

a shake correction magnet disposed on either one of the shake correction fixed portion and the shake correction movable portion; and

and a shake correction coil disposed on the other of the shake correction fixed portion and the shake correction movable portion.

12. A camera module, characterized in that,

the camera module includes:

the lens driving device according to any one of claims 1 to 11;

a lens unit attached to the shake correction movable unit; and

and an imaging unit that images the subject image formed by the lens unit.

13. A camera mounting device, which is an information apparatus or a transportation apparatus, is characterized in that,

the camera mounting device includes:

a camera module as in claim 12; and

and an image processing unit that processes image information obtained by the camera module.