Lens-driving device, camera module, and camera mount device

This lens-driving device is provided with: a shake correction drive unit which, utilizing the drive power of a voice coil motor, causes a moveable shake correction unit that includes a shake correction magnet unit to oscillate within a plane orthogonal to the optical axis with respect to a stationary shake correction unit that includes a shake correction magnet unit, in order to carry out shake correction; and a plurality of suspension wires for supporting the moveable shake correction unit with respect to the stationary shake correction unit. The moveable shake correction unit has a retaining member for retaining the shake correction magnet unit, and the retaining member has a wire passage part recessed inwardly in the diametrical direction and formed to have an inside diameter at the bottom which is larger than the inside diameter at the top, a suspension wire being arranged in the retaining member.

TECHNICAL FIELD

The present invention relates to a shake-correcting lens driving device, a camera module having a shake-correcting function, and a camera mounting device.

BACKGROUND ART

In general, a small-sized camera module is mounted in a mobile terminal such as a smartphone. In such a camera module, a lens driving device is employed (for example, PTL 1). The lens driving device has an auto-focusing function of automatically performing focusing for capturing a subject (hereinafter referred to as “AF (Auto Focus) function”), and a shake-correcting function (hereinafter referred to as “OIS (Optical Image Stabilization) function”) of correcting shake (vibration) upon capturing an image to reduce the irregularities of the image.

The auto-focusing and shake-correcting lens driving device includes an auto-focusing driving part (hereinafter referred to as “AF driving part”) for moving the lens part in the light axis direction, and a shake-correcting driving part (hereinafter referred to as “OIS driving part”) for swaying the lens part in a plane orthogonal to the light axis direction.

The AF driving part includes, for example, an auto-focusing coil part (hereinafter referred to as “AF coil part”) disposed around the lens part, and an auto-focusing magnet part (hereinafter referred to as “AF magnet part”) disposed separately from the AF coil part in the radial direction. Automatic focusing is performed by moving an AF movable part including the lens part and the AF coil part with respect to an AF fixing part including the AF magnet part in the light axis direction with use of a driving force of a voice coil motor composed of the AF coil part and the AF magnet part, for example.

Here, a lens position for bringing a subject at a smallest capture distance (a position on the most light reception side) into focus is called “macro position,” and a lens position for bringing a subject at the infinity (a position on the most imaging side) into focus is called “infinity position.” That is, the range from the macro position to the infinity position is the movable range of the AF movable part.

The OIS driving part includes a shake-correcting magnet part (hereinafter referred to as “OIS magnet part”) disposed at the AF driving part, and a shake-correcting coil part (hereinafter referred to as “OIS coil part”) disposed separately from the OIS magnet part in the light axis direction, for example. A shake correction movable part (hereinafter referred to as “OIS movable part”) including the AF driving part and the OIS magnet part is supported by a supporting member to be separated from a shake-correcting fixing part (hereinafter referred to as “OIS fixing part”) including the OIS coil part in the light axis direction. The OIS movable part is swayed in a plane orthogonal to the light axis direction by use of a driving force of a voice coil motor composed of the OIS magnet part and the OIS coil part, and thus shake correction is performed (so-called barrel shift system). The OIS magnet part can also serve as the AF magnet part, and with such a configuration, the size and the height of the lens driving device can be reduced.

In the above-described lens driving device, the OIS movable part (AF driving part) is fixed to the OIS fixing part with the four suspension wires disposed at the four corners of the peripheral portion, for example. When the suspension wire is deflected and brought into contact with the magnet holder (a member that holds the magnet part) at the time of swaying of the OIS movable part, the OIS movable part is tilted, and shake correction is not appropriately performed. In view of this, in the magnet holder, the portion near the suspension wire is largely cut out in a columnar shape (hereinafter referred to as “wire insertion part”) so as not to interfere with the swaying of the OIS movable part.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

In recent years, along with thickness reduction of mobile terminals, further downsizing of camera modules has been desired. However, when a given space is ensured as the wire insertion part in the case where the external shape is reduced for the purpose of downsizing, the mechanical strength of the magnet holder is reduced. On the other hand, when downsizing is achieved while ensuring the mechanical strength of the magnet holder, the size of the wire insertion part is reduced, and consequently the magnet holder and the suspension wire easily interfere with each other when the OIS movable part sways.

An object of the present invention is to provide a lens driving device, and a camera module and a camera mounting device including the lens driving device which can ensure the mechanical strength of a magnet holder while avoiding the interference with the suspension wire at the time of swaying, and can achieve further downsizing.

Solution to Problem

A lens driving device according to an embodiment of the present invention includes: a shake-correcting driving part including a shake-correcting magnet part disposed at a periphery of a lens part, and a shake-correcting coil part disposed separately from the shake-correcting magnet part in a light axis direction, the shake-correcting driving part being configured to perform shake correction by swaying a shake correction movable part including the shake-correcting magnet part with respect to a shake correction fixing part including the shake-correcting coil part in a plane orthogonal to the light axis direction by use of a driving force of a voice coil motor composed of the shake-correcting coil part and the shake-correcting magnet part; and a plurality of suspension wires configured to support the shake correction movable part with respect to the shake correction fixing part. The shake correction movable part includes a holding member configured to hold the shake-correcting magnet part, and the holding member includes a wire insertion part where the suspension wire is disposed, the wire insertion part being recessed inward in a radial direction such that an internal diameter of a lower portion is larger than an internal diameter of an upper portion.

A camera module according to an embodiment of the present invention includes: the above-mentioned lens driving device; a lens part that is mounted at to the shake correction movable part; and an image capturing part configured to capture a subject image imaged with the lens part.

A camera mounting device according to an embodiment of the present invention is an information apparatus or a transport apparatus, the above-mentioned camera mounting device including the camera module.

Advantageous Effects of Invention

According to the present invention, the mechanical strength of the magnet holder serving as the holding member can be ensured while avoiding the interference with the suspension wire at the time of swaying, and therefore further downsizing can be achieved.

DESCRIPTION OF EMBODIMENT

In the following, an embodiment of the present invention is described in detail with reference to the drawings.

FIGS. 1A and 1Billustrate smartphone M in which camera module A according to the embodiment of the present invention is mounted.FIG. 1Ais a front view of smartphone M, andFIG. 1Bis a rear view of smartphone M.

For example, smartphone M is provided with camera module A as a back side camera OC. Camera module A has an auto-focusing function and a shake-correcting function, and can capture an image without image blurring by automatically performing focusing at the time of capturing a subject and by correcting shake (vibration) at the time of capturing an image.

FIG. 2is a perspective view of an external appearance of camera module A.FIG. 3is an exploded perspective view of camera module A. As illustrated inFIG. 2andFIG. 3, descriptions will be made with an orthogonal coordinate system (X, Y, Z) in the present embodiment. Also in the drawings described later, descriptions will be made with an orthogonal coordinate system (X, Y, Z). Camera module A is mounted such that the vertical direction (or horizontal direction) is the X direction, the horizontal direction (or vertical direction) is the Y direction, and the front-rear direction is the Z direction at the time of actually capturing an image with smartphone M. That is, the Z direction is the light axis direction, the upper side in the drawing is the light reception side in the light axis direction (also referred to as “macro position side”), and the lower side is the imaging side in the light axis direction (also referred to as “infinity position side”).

Camera module A includes a lens part (not illustrated) in which a lens is housed in a lens barrel having a cylindrical shape, AF and OIS lens driving device1, an image capturing part (not illustrated) that captures a subject image imaged with the lens part, shield cover2that covers the entirety, and the like.

As viewed in the light axis direction, shield cover2is a capped square cylindrical body having a square shape in plan view. Circular opening2ais formed in the top surface of shield cover2. A lens part (not illustrated) is exposed to the outside through opening2a. Shield cover2is fixed to base member23(seeFIG. 6) of OIS fixing part20of lens driving device1. Shield cover2has conductivity. Shield cover2is electrically connected with ground terminal parts221and222of OIS fixing part20, and is grounded.

The image capturing part (not illustrated) includes an imaging device (not illustrated), and is disposed on the imaging side in the light axis direction of the lens driving device1. The imaging device (not illustrated) is composed of, for example, a CCD (charge coupled device) image sensor, a CMOS (complementary metal oxide semiconductor) image sensor, or and the like. The imaging device (not illustrated) captures a subject image imaged by a lens part (not illustrated).

FIG. 4is an exploded perspective view of lens driving device1. As illustrated inFIG. 4, lens driving device1includes OIS movable part10, OIS fixing part20, supporting member30and the like.

OIS movable part10includes an OIS magnet part serving as a component of the OIS voice coil motor, and sways in the XY plane at the time of shake correction. OIS fixing part20includes an OIS coil part. OIS movable part10includes an AF driving part.

OIS movable part10is disposed on the light reception side in the light axis direction relative to OIS fixing part20and is separated from OIS fixing part20. OIS movable part10is coupled with OIS fixing part20by supporting member30. To be more specific, supporting member30is composed of four suspension wires extending along the Z direction (hereinafter referred to as “suspension wire30”). One end (upper end) of suspension wire30is fixed to OIS movable part10(upper elastic supporting part13, seeFIG. 5), and the other end (lower end) of suspension wire30is fixed to OIS fixing part20(coil substrate21, seeFIG. 6). OIS movable part10is supported by suspension wire30such that OIS movable part10can sway in the XY plane. Two of the four suspension wires30are used for feeding power to AF coil part112(seeFIG. 5). It is to be noted that the number of suspension wires30is not limited, and five or more suspension wires30may be provided.

FIG. 5is an exploded perspective view of OIS movable part10. As illustrated inFIG. 5, OIS movable part10includes AF movable part11, AF fixing part12, upper elastic supporting part13, lower elastic supporting part14and the like. AF movable part11includes an AF coil part serving as a component of an AF voice coil motor, and moves in the light axis direction at the time of focusing. AF fixing part12is a part having an AF magnet part. That is, the AF driving part of lens driving device1is of a moving coil type. AF movable part11is disposed on the radially inside relative to AF fixing part12and is separated from AF fixing part12. AF movable part11is coupled with AF fixing part12by upper elastic supporting part13and lower elastic supporting part14.

Lens holder111is a member having a quadrangular cylindrical shape, and a lens part (not illustrated) is fixed to lens housing part111ahaving a cylindrical shape by bonding or screwing. Lens holder111includes upper flange part111band lower flange part111con the peripheral surface of lens housing part111a. AF coil part112is wound at a part (hereinafter referred to as “coil winding part”) sandwiched between upper flange part111band lower flange part111c.

Lens holder111includes, at positions corresponding to the four corners at an upper portion of the outer periphery of lens housing parts111a, upper spring fixing part111dfor fixing upper elastic supporting part13. Lens holder111includes tying parts111ethat protrude outward in a radial direction from two diagonally-opposite upper spring fixing parts111dof four upper spring fixing parts111d.

Top surface111fof upper flange part111bserves as a locking part for restricting movement of AF movable part11to the light reception side in the light axis direction (hereinafter referred to as “first locking part111f”). Lower elastic supporting part14is fixed to bottom surface111gof lower flange part111c(hereinafter referred to as “lower spring fixing part111g”).

Lens holder111includes protruding parts111hthat protrude outward in a radial direction over upper flange part111band lower flange part111cat opposite positions in the X direction and the Y direction of an upper portion of the outer periphery of lens housing part111a. Protruding part111hserves as a locking part for restricting movement of AF movable part11to the imaging side in the light axis direction (hereinafter referred to as “second locking part111h”).

AF coil part112is an air-core coil that is energized at the time of focusing, and is wound around the outer peripheral surface of a coil winding part of lens holder111. The both ends of AF coil part112are tied to tying parts111eof lens holder111.

AF fixing part12includes magnet holder121and magnet part122. WhileFIG. 5illustrates a state where magnet holder121is attached on magnet part122, magnet part122is attached after AF movable part11is inserted to magnet holder121in practice.

Magnet holder121has a quadrangular cylindrical shape which is square in plan view. Four connection parts (four sides extending along the Z-axis direction) connecting the side walls of magnet holder121are recessed to radially inside in an arc-like shape. Suspension wire30is disposed at this portion (hereinafter referred to as “wire insertion part121a”). With wire insertion part121a, interference between suspension wire30and magnet holder121at the time when OIS movable part10sways is avoided.

As illustrated inFIGS. 7A and 7Bin an enlarged manner, the internal diameter of wire insertion part121ais larger on the lower side than the upper side. Here, wire insertion part121ahas a truncated cone shape whose internal diameter gradually decreases from the imaging side toward the light reception side in the light axis direction.

The lower portion of suspension wire30is fixed to coil substrate21, and does not follow the sway of magnet holder121, and accordingly, the distance to magnet holder121thereof changes. In view of this, in wire insertion part121a, a portion corresponding to the lower portion of suspension wire30is largely cut out so that magnet holder121and suspension wire30do not interfere with each other at the time when OIS movable part10sways.

In contrast, the upper portion of suspension wire30follows the sway of magnet holder121, and therefore the distance to magnet holder121thereof is maintained. Accordingly, the size of the portion of wire insertion part121awhich corresponds to the upper portion of suspension wire30can be small. By setting the internal diameter of wire insertion part121asuch that the internal diameter of the upper portion is smaller than that of the lower portion, the mechanical strength of magnet holder121can be increased. Accordingly, the size of the external shape of magnet holder121can be set to a small value, and in turn, downsizing of lens driving device1can be achieved.

Magnet holder121includes, at the upper portion, stopper parts121bthat protrude inward in the radial direction in a ring-shape. In stopper part121b, the portion corresponding to second locking part111hand upper spring fixing part111dof lens holder111is cut out such that AF movable part11can move to the light reception side in the light axis direction relative to the top surface of magnet holder121. When AF movable part11moves to the light reception side in the light axis direction, stopper part121bmakes contact with first locking part111fof lens holder111, and thus the movement of AF movable part11to the light reception side in the light axis direction is restricted. In addition, arm parts131cand132cof upper elastic supporting part13are placed on the top surface of stopper part121b. The top surface of magnet part122makes contact with the bottom surface of stopper part121b.

Lower elastic supporting part14is fixed to bottom surface121eof magnet holder121(hereinafter referred to as “lower spring fixing part121e”). Magnet holder121includes, at the four corners of the upper portion, upper spring fixing parts121cthat fix upper elastic supporting part13. The peripheral portion of the upper boss having a trapezoidal columnar shape disposed in upper spring fixing part121cis slightly recessed from the top surface (the surface on which upper elastic supporting part13is attached) of magnet holder121such that a gap (damper installation part121d) is formed when upper elastic supporting part13is attached. The corner (the portion provided continuously with the upper portion of wire insertion part121a) of damper installation part121dprotrudes to the outside relative to the lower portion, and is cut out in an arc-like shape. The cut-out portion having an arc-like shape of damper installation part121dforms a part of wire insertion part121a.

Magnet part122includes four permanent magnets each having a cuboid shape. Magnet part122is disposed along the internal surface of each of the four side walls of magnet holder121. Magnet parts122are magnetized such that a traversing magnetic field in the radial direction is formed at AF coil part112. For example, magnet parts122are magnetized such that the inner periphery side and the outer periphery side thereof are set to N pole and S pole, respectively.

The AF voice coil motor is composed of magnet part122and AF coil part112. In the present embodiment, magnet part122serves as the AF magnet part and as the OIS magnet part.

Upper elastic supporting part13is a leaf spring formed of beryllium copper, nickel copper, stainless-steel or the like, for example, and has a square shape as a whole in plan view. Upper elastic supporting part13elastically connects AF fixing part12(magnet holder121) and AF movable part11(lens holder111).

Upper elastic supporting part13is composed of two upper leaf springs13A and13B (upper elastic supporting members) which are disposed in a point-symmetrical manner about the light axis. Each of upper leaf springs13A and13B includes spring parts131and132. Since the configurations of upper spring parts13A and13B are similar to each other, the description of upper leaf spring13B is omitted.

In upper leaf spring13A, spring part131includes lens holder fixing part131athat is fixed to lens holder111, magnet holder fixing part131bthat is disposed at a position at 90 degrees from lens holder fixing part131aand is fixed to magnet holder121, and arm part131cthat couples lens holder fixing part131aand magnet holder fixing part131b. In addition, lens holder fixing part131aincludes coil connecting part131dthat has a U-shape in plan view and is bonded by soldering to an end portion of AF coil part112.

Likewise, spring part132includes lens holder fixing part132athat is fixed to lens holder111, magnet holder fixing part132bthat is disposed at a position at 90 degrees from lens holder fixing part132aand is fixed to magnet holder121, and arm part132cthat couples lens holder fixing part132aand magnet holder fixing part132b.

Lens holder fixing parts131aand132aare coupled by inner coupling part133at a position inside arm part131c. In addition, magnet holder fixing parts131band132bare coupled by outer coupling part134at a position outside arm part132c.

Each of lens holder fixing parts131aand132ahas a shape corresponding to upper spring fixing part111dof lens holder111. When the positioning bosses of lens holder111are fitted into the fixing holes of lens holder fixing parts131aand132a, upper leaf springs13A and13B are positioned and fixed to lens holder111. Coil connecting part131dis electrically connected by soldering with AF coil part112tied to tying part111eof lens holder111.

Each of magnet holder fixing parts131band132bhas a shape corresponding to upper spring fixing part121cof magnet holder121. When the positioning bosses of upper spring fixing parts121care fitted into the fixing holes of magnet holder fixing parts131band132b, upper leaf springs13A and13B are positioned and fixed to magnet holder121. In addition, each of vertex parts131eand132eof magnet holder fixing parts131band132bserves as a wire connecting part (hereinafter referred to as “wire connecting parts131eand132e”) where suspension wire30is connected.

Wire connecting parts131eand132eare located on the light reception side of wire insertion part121aof magnet holder121in the light axis direction. In the state where upper leaf springs13A and13B are attached to magnet holder121, a gap is formed between damper installation part121dand wire connecting parts131eand132e. A damper is disposed in this gap. In addition, each of wire connecting parts131eand132ehas a shape which is easily elastically deformed. With deflection of wire connecting parts131eand132eand suspension wire30, drop impact is absorbed. Thus, plastic deformation and rupture of suspension wire30with drop impact can be effectively prevented.

Arm parts131cand132ccouple lens holder fixing part131aand magnet holder fixing part131b, and lens holder fixing part132aand magnet holder fixing part132b, respectively. Each of arm parts131cand132cis formed in an arc-like shape, and is elastically deformed when AF movable part11moves.

As with upper elastic supporting part13, lower elastic supporting part14is a leaf spring (hereinafter referred to as “lower leaf spring14”) made of beryllium copper, nickel copper, stainless-steel or the like. Lower elastic supporting part14elastically connects AF fixing part12(magnet holder121) and AF movable part11(lens holder111).

Lower leaf spring14(lower elastic supporting member) includes four spring parts141to144. Spring part141includes lens holder fixing part141athat is fixed to lens holder111, magnet holder fixing part141bthat is disposed at a position at 90 degrees from lens holder fixing part141aand is fixed to magnet holder121, and arm part141cthat couples lens holder fixing part141aand magnet holder fixing part141b. The configurations of spring parts142to144are similar to the above-mentioned configuration.

In lens holder fixing parts141ato144a, the lens holder fixing parts adjacent to each other are coupled with coupling part145to have a shape corresponding to lower spring fixing part111gof lens holder111. When the positioning bosses of lens holder111are fitted into the fixing holes of lens holder fixing parts141ato144a, lower leaf spring14is positioned and fixed to lens holder111.

Magnet holder fixing parts141bto144bhave shapes corresponding to lower spring fixing part121eof magnet holder121. When the positioning bosses of upper spring fixing parts121care fitted into the fixing holes of magnet holder fixing parts131band132b, upper leaf springs13A and13B are positioned and fixed to magnet holder121.

At the time of assembling OIS movable part10(AF driving part), first, magnet holder fixing parts131band132bof upper leaf springs13A and13B are attached to upper spring fixing part121cof magnet holder121. In addition, lens holder fixing parts141ato144aof lower leaf spring14are attached to lower spring fixing part111gof lens holder111.

Next, lens holder111is fitted into magnet holder121from the imaging side in the light axis direction. At this time, second locking part111hand upper spring fixing part111dof lens holder111are fitted to the cutout of stopper part121bof magnet holder121. Then, lens holder fixing parts131aand132aof upper leaf springs13A and13B are attached to upper spring fixing parts111dof lens holder111. Coil connecting part131dis bonded by soldering to the both ends of AF coil part112tied to tying part111eof lens holder111, so as to be electrically connected. In addition, magnet holder fixing parts141bto144bof lower leaf spring14are attached to lower spring fixing part121eof magnet holder121.

Next, magnet part122is inserted from the imaging side in the light axis direction, and bonded to magnet holder121. In this manner, OIS movable part10(AF driving part) is assembled.

In plan view, coil substrate21has a square shape, and has circular opening21aat a center portion. Coil substrate21includes, at the four corners, wire fixing holes21bthrough which the other end (lower end) of suspension wire30is inserted. In addition, coil substrate21includes, at positions which intersect the diagonal direction of peripheral portions of opening21a, positioning holes21c.

Coil substrate21includes OIS coil part211at a position opposite to magnet part122in the light axis direction. OIS coil part211includes four OIS coils211A to211D corresponding to magnet parts122. The sizes and positions of OIS coil part211and magnet part122and magnet parts122are set such that the magnetic field radiated from the bottom surfaces of magnet parts122traverses the long side portions of OIS coils211A to211D in the Z direction. The OIS voice coil motor is composed of magnet part122and OIS coil part211.

As with coil substrate21, sensor substrate22has a square shape in plan view, and has circular opening22aat a center portion. Sensor substrate22includes, at peripheral portions of opening22a, positioning holes22bat positions corresponding to positioning holes21cof coil substrate21. Sensor substrate22includes, at two sides along the Y direction, control terminal parts223and224that are bent downward. Sensor substrate22includes, at the two sides along the X direction (the two sides opposite to each other in the Y direction), ground terminal parts221and222. Ground terminal parts221and222are electrically connected with shield cover2.

Ground terminal part221is composed of ground terminals221A and221B having different lengths that are protruded outward and bent downward (hereinafter referred to as “first ground terminal221A” and “second ground terminal221B”). Likewise, ground terminal part222is composed of ground terminals222A and222B having different lengths that are protruded outward and bent downward (hereinafter referred to as “third ground terminal222A” and “fourth ground terminal222B”). That is, the lengths of the ground terminals in one side are different from each other.

Here, first ground terminal221A and third ground terminal222A have the longer length, and second ground terminal221B and fourth ground terminal222B have the shorter length. That is, the lengths of the ground terminals opposite to each other in the Y direction are equal to each other. It is to be noted that the lengths of the ground terminals opposite to each other in the Y direction may be different from each other.

The length of first ground terminal221A is set such that the contact area with shield cover2is sufficiently ensured even when protruding length L1of first ground terminal221A to first ground terminal housing part231A (seeFIG. 8) is small due to the attaching tolerance of sensor substrate22attached to base member23. In addition, the length is set such that first ground terminal221A is housed in first ground terminal housing part231A (or that first ground terminal221A is not placed onto side surface23dof base member23) even when the protruding length of first ground terminal221A to first ground terminal housing part231A is large. The same applies to third ground terminal222A.

The length of second ground terminal221B is set such that the distance from the edge of base member23(that is, side surface23d) is sufficiently ensured even when protruding length L2of second ground terminal221B to second ground terminal housing part231B (seeFIG. 8) is large due to the attaching tolerance of sensor substrate22attached to base member23. In addition, the length is set such that second ground terminal221B is exposed to second ground terminal housing part231B even when the protruding length of second ground terminal221B to second ground terminal housing part231B is small. The same applies to fourth ground terminal222B.

Sensor substrate22includes a power-source line (not illustrated) for power feeding to AF coil part112and OIS coil part211, and a signal line (not illustrated) for a detection signal output from position detection part24. Position detection part24that detects the position of OIS movable part10in the XY plane is disposed on the bottom surface of sensor substrate22.

Position detection part24is composed of Hall devices24A and24B (magnetic sensors) that detect the magnetic field by utilizing Hall effect, for example. Hall devices24A and24B are respectively disposed at adjacent two sides of the bottom surface of sensor substrate22, at an approximate center thereof. By detecting the magnetic field formed by magnet part122with Hall devices24A and24B, the position of OIS movable part10in the XY plane can be specified. It is to be noted that a magnet for position detection may be disposed independently of magnet part122in OIS movable part10.

As with coil substrate21, base member23has a square shape in plan view, and has circular opening23aat a center portion. Base member23includes, at peripheral portions of opening23a, positioning bosses23bat positions corresponding to positioning holes21cof coil substrate21and positioning holes22bof sensor substrate22. In addition, base member23includes, at peripheral portions of opening23a, Hall device housing parts23eat positions corresponding to Hall devices24A and24B.

Base member23includes, at positions corresponding to control terminal parts223and224of sensor substrate22at the two sides of the peripheral portion along the Y direction, control terminal housing parts233and234which are further recessed from side surface23d. In addition, base member23includes, at positions corresponding to ground terminals221and222of sensor substrate22at the two sides of the peripheral portion along the X direction, ground terminal housing parts231and232further recessed from side surface23d.

Ground terminal housing part231includes first ground terminal housing part231A where first ground terminal221A is disposed, and second ground terminal housing part231B where second ground terminal221B is disposed. Likewise, ground terminal housing part232includes third ground terminal housing part232A where third ground terminal222A is disposed, and fourth ground terminal housing part232B where fourth ground terminal222B is disposed.

Along protruding part23c, first ground terminal221A to fourth ground terminal222B are disposed to first ground terminal housing part231A to fourth ground terminal housing part232B, respectively. First ground terminal221A to fourth ground terminal222B are separated from the reference surfaces of first ground terminal housing part231A to fourth ground terminal housing part232B. With this configuration, first ground terminal221A to fourth ground terminal222B are flush with side surface23dof base member23.

Base member23includes, in the region except for the regions of ground terminal housing parts231and232in the two sides where ground terminal housing parts231and232are provided, cover placing part23ffor placing shield cover2. Cover placing part23fis formed by recessing a part of the cover placing surface such that adhesive agent inlet23gis formed when shield cover2is placed (seeFIG. 2).

At the time of assembling OIS fixing part20, first, coil substrate21and sensor substrate22are bonded by soldering. In this manner, the power-source line (not illustrated) of sensor substrate22and OIS coil part211are electrically connected to each other. Depending on the attaching tolerance at this time, the protruding lengths of ground terminals221and222in ground terminal housing parts231and232of base member23change.

Next, positioning holes21cof coil substrate21and positioning holes22bof sensor substrate22are fitted to positioning bosses23bof base member23, to dispose coil substrate21and sensor substrate22on base member23. When ground terminal parts221and222of sensor substrate22are engaged with ground terminal housing parts231and232of base member23, and control terminal parts223and224are engaged with control terminal housing parts233and234, coil substrate21and sensor substrate22are fixed to base member23. In this manner, OIS fixing part20is assembled.

Here, ground terminal parts221and222are separated from the edges of ground terminal housing parts231and232, that is, side surface23dof base member23.FIG. 8illustrates an attaching state of ground terminal part221to base member23. As illustrated inFIG. 8, protruding length L1of first ground terminal221A to base member23and protruding length L2of second ground terminal221B to base member23are different from each other.

When the attachment position of sensor substrate22is shifted as a whole to the base end side in the Y direction (ground terminal housing part232side of base member23) with an attaching tolerance, protruding length L1of first ground terminal221A to first ground terminal housing part231A (seeFIG. 8) and protruding length L2of second ground terminal221B to second ground terminal housing part231B (seeFIG. 8) decrease. In this case, the contact area between second ground terminal221B and shield cover2decreases. Consequently, the conduction state between second ground terminal221B and shield cover2is easily impaired. On the other hand, the contact area between first ground terminal221A and shield cover2is sufficiently ensured although the contact area decreases. Accordingly, a favorable conduction state between first ground terminal221A and shield cover2is ensured.

In addition, when the attachment position of sensor substrate22is shifted as a whole to the front end side in the Y direction (ground terminal housing part231side of base member23) with an attaching tolerance, protruding length L1of first ground terminal221A to first ground terminal housing part231A and protruding length L2of second ground terminal221B to second ground terminal housing part231B increase. In this case, the end of first ground terminal221A is close to the edge of first ground terminal housing part231A (that is, side surface23d), and the adhesive agent may possibly enter the portion between first ground terminal221A and shield cover2, thus causing partial insulation. Consequently, the conduction state between first ground terminal221A and shield cover2is easily impaired. On the other hand, the end of second ground terminal221B is sufficiently separated from the edge of second ground terminal housing part231B even when protruding length L2increases. Accordingly, the possibility of entrance of the adhesive agent to the portion between second ground terminal231B and shield cover2is low, and a favorable conduction state between second ground terminal221B and shield cover2is ensured.

As described above, even when the protruding length of the ground terminal is changed with an attaching tolerance and the conduction state between one of the ground terminals (for example, first ground terminal221A) and shield cover2can be easily impaired, the conduction state between the other ground terminal (for example, second ground terminal221B) and shield cover2is ensured. Accordingly, lens driving device1has high reliability and is resistant to drop impact and the like.

The same applies to the conduction state between third ground terminal222A and shield cover2, and the conduction state between fourth ground terminal222B and shield cover2. In this manner, with a plurality of ground terminals having different lengths (first ground terminal221A and second ground terminal221B, and third ground terminal222A and fourth ground terminal222B) disposed at the opposite two sides of the peripheral portion, the reliability of lens driving device1can be further increased.

At the time of assembling lens driving device1, one end (upper end) of suspension wire30is inserted to wire connecting part131eof upper leaf springs13A and13B and is fixed by soldering. In this manner, suspension wire30and upper leaf springs13A and13B are electrically connected to each other.

In addition, the other end (lower end) of suspension wire30is inserted to wire fixing hole21bof coil substrate21and is fixed by soldering. In this manner, suspension wire30and the power-source line of sensor substrate22are electrically connected to each other. Through suspension wire30and upper leaf springs13A and13B, power can be fed to AF coil part112.

In addition, a damper (not illustrated) is disposed at damper installation part121d(including upper portion of wire insertion part121a) of magnet holder121in such a manner as to surround suspension wire30. Thus the damper is interposed between magnet holder121and upper leaf springs13A and13B. By interposing the damper (not illustrated) between magnet holder121and upper leaf springs13A and13B, generation of unnecessary resonance (high-order resonance mode) can be reduced, and consequently, the stability of the operation can be ensured. The damper can be readily applied to damper installation part121iby use of a dispenser. For example, ultraviolet curing silicone gel can be adopted as the damper.

Shield cover2is attached to lens driving device1such that a lower inner peripheral surface of shield cover2makes contact with ground terminals221and222of sensor substrate22. To be more specific, shield cover2is placed to cover placing part23fof base member23, and adhesive agent is supplied from adhesive agent inlet23g. By capillarity, the supplied adhesive agent fills the portion between shield cover2and side surface23dof base member23, thus bonding shield cover2and side surface23dof base member23. At this time, the advancement of the adhesive agent is blocked by the step of ground terminal housing parts231and232and side surface23d, and therefore the adhesive agent does not flow into ground terminal housing parts231and232. By adjusting the supply amount of the adhesive agent, inflow of the adhesive agent to ground terminal housing parts231and232can be readily prevented.

In lens driving device1, when OIS coil part211is energized, a Lorentz force is generated at OIS coil part211by interaction between the magnetic field of magnet part122and the current flowing through OIS coil part211(Fleming's left hand rule). The direction of the Lorentz force is the direction (the Y direction or the X direction) orthogonal to the direction of the magnetic field (the Z direction) and to the direction of the current flowing through the long side portion of OIS coil part211(the X direction or the Y direction). Since OIS coil part211is fixed, a reactive force acts on magnet part122. With this reactive force serving as the driving force of the OIS voice coil motor, OIS movable part10including magnet part122sways in the XY plane, and thus shake correction is performed.

In addition, in lens driving device1, when AF coil part112is energized, a Lorentz force is generated at AF coil part112by interaction between the magnetic field of magnet part122and the current flowing through AF coil part112. The direction of the Lorentz force is the direction (the Z direction) orthogonal to the direction of the magnetic field (X direction or Y direction) and the direction of the current flowing through the AF coil part211(the Y direction or the X direction). Since magnet part122is fixed, a reactive force acts on AF coil part112. With this reactive force serving as the driving force of the AF voice coil motor, AF movable part11including AF coil part112moves in the light axis direction, and thus focusing is performed.

Here, in an non-energization state where focusing is not performed, AF movable part11is suspended between the infinity position and the macro position with upper leaf springs13A and13B and lower leaf spring14(hereinafter referred to as “reference state”). That is, in OIS movable part10, AF movable part11(lens holder111) is elastically supported such that AF movable part11is displaceable in the Z direction in the state where the position of AF movable part11with respect to AF fixing part12(magnet holder121) is set by upper leaf springs13A and13B, and lower leaf spring14.

At the time of focusing, the direction of the current is controlled based on whether AF movable part11is moved from the reference state to the macro position side or to the infinity position side. In addition, the value of the current is controlled based on the movement length of AF movable part11.

As described above, lens driving device1includes an OIS driving part (shake-correcting driving part) and a plurality of suspension wires30. The OIS driving part includes magnet part122(shake-correcting magnet part) disposed at a periphery of a lens part (not illustrated), and OIS coil part211(shake-correcting coil part) disposed separately from magnet part122in a light axis direction. The OIS driving part is configured to perform shake correction by swaying OIS movable part10(shake correction movable part) including magnet part122with respect to OIS fixing part20(shake correction fixing part) including OIS coil part211in a plane orthogonal to the light axis direction by use of a driving force of a voice coil motor composed of OIS coil part211and magnet part122. Suspension wires30support OIS movable part10with respect to OIS fixing part20. OIS movable part10includes magnet holder121(holding member) configured to hold magnet part122. Magnet holder121includes wire insertion part121awhere suspension wire30is disposed. Wire insertion part121ais recessed inward in a radial direction in an arc-like shape such that an internal diameter of a lower portion is larger than an internal diameter of an upper portion.

With lens driving device1, the mechanical strength of magnet holder121serving as the holding member can be ensured while avoiding the interference with the suspension wire at the time when OIS movable part10sways. Accordingly, further downsizing can be achieved.

While the invention made by the present inventor has been specifically described based on the preferred embodiments, it is not intended to limit the present invention to the above-mentioned preferred embodiments but the present invention may be further modified within the scope and spirit of the invention defined by the appended claims.

For example, while the lens driving device has an AF function and an OIS function in the embodiment, the present invention is applicable to a lens driving device having an OIS function, that is, a structure in which an OIS movable part is supported and fixed to an OIS fixing part with a suspension wire.

In addition, for example, while wire insertion part121ahas a truncated cone shape whose internal diameter gradually changes in the embodiment, wire insertion part121amay have a structure having a multistep shape whose internal diameter changes stepwise.

While a smartphone serving as a camera-equipped mobile terminal is described in the embodiment as an example of a camera mounting device having camera module A, the present invention is applicable to a camera mounting device serving as an information apparatus or a transport apparatus. The camera mounting device serving as an information apparatus is an information apparatus including a camera module and a control section that processes image information obtained with the camera module, such as a camera-equipped mobile phone, a note-type personal computer, a tablet terminal, a mobile game machine, a webcamera, and a camera-equipped in-vehicle apparatus (for example, a rear-view monitor apparatus or a drive recorder apparatus). In addition, the camera mounting device serving as a transport apparatus is a transport apparatus including a camera module and a control section that processes an image obtained with the camera module, such as an automobile.

FIGS. 9A and 9Billustrate automobile C serving as a camera mounting device in which an in-vehicle camera module vehicle camera (VC) is mounted.FIG. 9Ais a front view of automobile C, andFIG. 9Bis a rear perspective view of automobile C. In automobile C, camera module A described in the embodiment is mounted as in-vehicle camera module VC. As illustrated inFIG. 9, in-vehicle camera module VC is attached to the windshield so as to face the front side, or attached to the rear gate so as to face the rear side, for example. This in-vehicle camera module VC is used for a rear-view monitor, a drive recorder, collision-avoidance control, automatic operation control, and the like.

As illustrated inFIG. 10, in upper leaf springs13A and13B (upper elastic supporting members) according to the embodiment, wire connecting parts131eand132eare disposed at the apexes of magnet holder fixing parts131band132b. That is, upper leaf springs13A and13B include link parts135aand135bextending from the supporting member main body toward the respective corners, and the joining portions of link parts135aand135bare wire connecting parts131eand132e, respectively.

At the time when OIS movable part10sways for shake correction, a large load is exerted on the coupling portion of suspension wire30and wire connecting parts131eand132eby the pulling force of suspension wire30, and a stress is caused at link parts135aand135b. When this stress is excessive, OIS movable part10is tilted, and consequently the tilt characteristics are reduced, thus causing problems such as out-of-focus at end portions of an image.

In particular, such problems are not negligible since reduction in tilt characteristics is remarkable in the case where suspension wire30is required to be shortened in view of the demand of reducing the height of lens driving device1, and the case where the movable range of OIS movable part10is required to be increased for improving the shake correction performance.

FIG. 11is a plan view illustrating a modification of upper leaf springs13A and13B.FIGS. 12A and 12Billustrate wire insertion part121ain lens driving device1in which upper leaf springs13A and13B according to the modification are applied.

As illustrated inFIG. 11, upper leaf springs13A and13B according to the modification include wire connecting parts131eand132eto which an end portion of suspension wire30is connected, first link parts136aand136bextending from the supporting member main body, and second link parts136cextending inward in the radial direction from the end portions (joining portions) of first link parts136aand136b, with wire connecting part131eand132ebeing disposed at an end of second link part136c. To be more specific, first link parts136aand136bextend toward respective corners of upper leaf springs13A and13B, and second link parts136cextend inward in the radial direction from the apexes of the respective corners.

It is to be noted that, as illustrated inFIG. 13, in upper leaf springs13A and13B, second link parts136cand136cmay be bent so as to extend inward in the radial direction from first link parts136aand136b. Since link parts136do not extend to the apexes of the respective corners, this structure is suitable for reducing the external size.

As described above, in upper leaf springs13A and13B according to the modification, link part136interposed between the supporting member main body and wire connecting parts131eand132eis formed with first link parts136aand136band second link part136c, thus achieving multiple joints while ensuring the link length.

With this configuration, the stress exerted on link part136at the time of shake correction is reduced, and consequently the tilt characteristics are improved. In an experiment, it was confirmed that the maximum stress applied to upper leaf springs13A and13B was reduced by 29%, and the tilt angle was changed to 1/10 when OIS movable part10was moved by 0.12 mm. Accordingly, upper leaf springs13A and13B according to the modification are suitable also for the demand of reducing the height and improvement of shake correction performance. In addition, the maximum stress applied to suspension wire30is reduced by 35%, and the impact resistance improves.

While interference between magnet wire121and suspension wire30may possibly occur when upper leaf springs13A and13B according to the modification are applied, interference with suspension wire30can be avoided even when the movable range of OIS movable part10is increased since wire insertion part121ais recessed inward in an arc-like shape in the radial direction such that the internal diameter of the lower portion is larger than the internal diameter of the upper portion (seeFIGS. 12A and 12B).

The embodiment disclosed herein is merely an exemplification and should not be considered as limitative. The scope of the present invention is specified by the following claims, not by the above-mentioned description. It should be understood that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors in so far as they are within the scope of the appended claims or the equivalents thereof.

This application is entitled to and claims the benefit of Japanese Patent Application No. 2014-265996 dated Dec. 26, 2014, the disclosure of which including the specification, drawings and abstract is incorporated herein by reference in its entirety.

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