US20110235197A1 - Lens drive device - Google Patents
Lens drive device Download PDFInfo
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- US20110235197A1 US20110235197A1 US13/071,706 US201113071706A US2011235197A1 US 20110235197 A1 US20110235197 A1 US 20110235197A1 US 201113071706 A US201113071706 A US 201113071706A US 2011235197 A1 US2011235197 A1 US 2011235197A1
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- Prior art keywords
- face
- lens
- drive
- magnetic member
- drive device
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- 230000002093 peripheral effect Effects 0.000 claims abstract description 149
- 230000003287 optical effect Effects 0.000 claims abstract description 74
- 239000000696 magnetic material Substances 0.000 claims description 15
- 230000004907 flux Effects 0.000 description 18
- 230000001413 cellular effect Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000003384 imaging method Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
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Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
- G02B7/02—Mountings, adjusting means, or light-tight connections, for optical elements for lenses
- G02B7/04—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification
- G02B7/08—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification adapted to co-operate with a remote control mechanism
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B3/00—Focusing arrangements of general interest for cameras, projectors or printers
- G03B3/10—Power-operated focusing
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K33/00—Motors with reciprocating, oscillating or vibrating magnet, armature or coil system
- H02K33/18—Motors with reciprocating, oscillating or vibrating magnet, armature or coil system with coil systems moving upon intermittent or reversed energisation thereof by interaction with a fixed field system, e.g. permanent magnets
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K41/00—Propulsion systems in which a rigid body is moved along a path due to dynamo-electric interaction between the body and a magnetic field travelling along the path
- H02K41/02—Linear motors; Sectional motors
- H02K41/035—DC motors; Unipolar motors
- H02K41/0352—Unipolar motors
- H02K41/0354—Lorentz force motors, e.g. voice coil motors
- H02K41/0356—Lorentz force motors, e.g. voice coil motors moving along a straight path
Definitions
- At least an embodiment of the present invention may relate to a lens drive device for use with at least one lens which is used in a relatively small camera that is mounted on a cellular phone or the like.
- a lens drive device has been conventionally known in which a photographing lens for a camera that is mounted on a cellular phone or the like is driven.
- the lens drive device is provided with a lens holder, which holds a plurality of lenses and is moved in an optical axis direction, and a drive mechanism part for driving the lens holder in the optical axis direction (see, for example, Japanese Patent Laid-Open No. 2009-198948).
- a drive coil which is wound around in a square shape is fixed to an outer peripheral side of the lens holder and two drive magnets are disposed so as to interpose the drive coil from both sides in the optical axis direction.
- At least an embodiment of the present invention may advantageously provide a lens drive device which is capable of being made thinner in the optical axis direction while securing a stroke of the lens.
- a lens drive device including a movable body which holds a lens and is movable in an optical axis direction of the lens, a fixed body which movably holds the movable body in the optical axis direction, and a drive mechanism for driving the movable body in the optical axis direction.
- the drive mechanism includes a drive coil which is fixed to the movable body, and a plurality of drive magnets which is formed in a substantially columnar shape or a substantially plate shape and fixed to the fixed body, and the drive magnet is magnetized so that a magnetic pole of one end face is different from a magnetic pole of the other end face in the optical axis direction.
- the fixed body includes an outer peripheral side magnetic member, which is formed of magnetic material and formed in a substantially tube-like shape and structures an outer peripheral face of the fixed body, and an end face side magnetic member which is formed of magnetic material and to which the one end face of the drive magnet is fixed.
- An inner peripheral face of the outer peripheral side magnetic member and a side face of the drive magnet are faced each other through a predetermined space.
- the outer peripheral side magnetic member, the end face side magnetic member and the drive magnet are disposed so that a magnetic field is formed so as to pass through the drive magnet, the end face side magnetic member and the outer peripheral side magnetic member and returned to the other end face of the drive magnet from the inner peripheral face of the outer peripheral side magnetic member, or returned to the inner peripheral face of the outer peripheral side magnetic member from the other end face of the drive magnet, and the drive coil is disposed between the other end face side of the drive magnet and the inner peripheral face of the outer peripheral side magnetic member.
- an inner peripheral face of the outer peripheral side magnetic member which is formed in a substantially tube-like shape and structures an outer peripheral face of the fixed body is disposed so as to face a side face of the drive magnet which is formed in a substantially columnar shape or a substantially plate shape through a predetermined space and the drive coil is disposed between the other end face side of the drive magnet in the optical axis direction and the inner peripheral face of the outer peripheral side magnetic member. Therefore, even when the movable body is moved in the optical axis direction, the drive magnet and the drive coil are not interfered with each other.
- the lens drive device is made thinner in the optical axis direction, a stroke of the movable body in the optical axis direction, in other words, a stroke of the lens in the optical axis direction is secured.
- the lens drive device is made thinner while securing a stroke of the lens.
- the outer peripheral side magnetic member and the end face side magnetic member are formed in an integral manner.
- the fixed body is provided with a cover member which is formed in a substantially bottomed tube-like shape in which the end face side magnetic member is a bottom part and the outer peripheral side magnetic member is a tube part that is integrally formed with the bottom part, and the end face side magnetic member structures an end face on an object to be photographed or imaged side of the lens drive device. According to this structure, leakage of a magnetic flux from a portion between the end face side magnetic member and the outer peripheral side magnetic member is prevented.
- an end face of the end face side magnetic member is abutted with the inner peripheral face of the outer peripheral side magnetic member. According to this structure, leakage of a magnetic flux from a portion between the end face side magnetic member and the outer peripheral side magnetic member is restrained and thus a magnetic flux density passing through the drive coil is enhanced. Therefore, even when the drive magnet and the drive coil are made thinner, a driving force of the drive mechanism is secured.
- the inner peripheral face of the outer peripheral side magnetic member and the side face of the drive magnet which are faced each other are substantially parallel to each other. According to this structure, directions of magnetic lines of force generated from the drive magnet are easily directed from the other end face of the drive magnet to the inner peripheral face of the outer peripheral side magnetic member, or easily directed from the inner peripheral face of the outer peripheral side magnetic member to the other end face of the drive magnet and thus a magnetic flux density passing through the drive coil is enhanced. Therefore, even when the drive magnet and the drive coil are made thinner, a driving force of the drive mechanism is secured.
- the other end face of the drive magnet is fixed with a second end face side magnetic member which is formed of magnetic material, and the magnetic field is directed from the inner peripheral face of the outer peripheral side magnetic member to the other end face of the drive magnet through the second end face side magnetic member, or the magnetic field is directed from the other end face of the drive magnet to the inner peripheral face of the outer peripheral side magnetic member through the second end face side magnetic member.
- the second end face side magnetic member is fixed to the other end face of the drive magnet, a magnetic flux is concentrated on the second end face side magnetic member. Therefore, according to this structure, a magnetic flux density passing through the drive coil is enhanced.
- a width in the optical axis direction of the drive coil is set to be a width in which the second end face side magnetic member is always located and faced on an inner peripheral side of the drive coil over a moving range of the movable body.
- a shape of the drive magnet when viewed in the optical axis direction is substantially the same as a shape of the second end face side magnetic member when viewed in the optical axis direction.
- a shape of the drive magnet when viewed in the optical axis direction is different from a shape of the second end face side magnetic member when viewed in the optical axis direction
- directions of magnetic lines of force generated from the drive magnet are easily directed from the other end face of the drive magnet to the inner peripheral face of the outer peripheral side magnetic member, or easily directed from the inner peripheral face of the outer peripheral side magnetic member to the other end face of the drive magnet. Therefore, according to this structure, a magnetic flux density passing through the drive coil is further enhanced.
- the drive mechanism is provided with one drive coil which is wound around in a tube-like shape and disposed along the inner peripheral face of the outer peripheral side magnetic member.
- a structure of the lens drive device is simplified.
- handling of end parts of a conducting wire structuring the drive coil is simplified and thus manufacturing steps for the lens drive device are simplified.
- the movable body is provided with a sleeve which holds a lens holder to which the lens is fixed, the sleeve is formed with two flange parts which are separated from each other through a predetermined space in the optical axis direction, the flange part which is disposed on a side of the end face side magnetic member is formed with an arrangement hole within which a part of the drive magnet is disposed, and the drive coil is fixed between the two flange parts of the sleeve so as to be fixed on an outer peripheral side of the arrangement hole.
- a shape of the lens drive device when viewed in the optical axis direction is formed in a substantially square shape or a substantially rectangular shape, and the drive magnet is disposed at four corners of the lens drive device.
- the drive magnet may be disposed at four corners of the lens drive device which is liable to be dead spaces. Therefore, the size of the lens drive device whose shape when viewed in the optical axis direction is formed in a substantially square shape or a substantially rectangular shape can be reduced.
- the drive magnet is formed in a substantially triangular prism shape. According to this structure, even when spaces of four corners of the lens drive device are made relatively small, the drive magnet is disposed at four corners of the lens drive device. Therefore, the size of the lens drive device can be further reduced. Further, according to this structure, the inner peripheral face of the outer peripheral side magnetic member and the side face of the drive magnet can be disposed to be substantially parallel to each other and thus, as described above, a magnetic flux density passing through the drive coil can be enhanced.
- the drive mechanism may be provided with one drive coil which is wound around in a tube-like shape and disposed along the inner peripheral face of the outer peripheral side magnetic member, or the drive mechanism may be provided with four drive coils each of which is wound around in a substantially triangular tube-like shape and faces the side face of the drive magnet through a predetermined gap space.
- a shape of the lens drive device for use with at least one lens when viewed in the optical axis direction is formed in a substantially rectangular shape, and the drive magnet is disposed on both sides of the lens drive device in a direction substantially parallel to a long side of the lens drive device when viewed in the optical axis direction.
- the size of the lens drive device is further reduced in a direction substantially parallel to a short side of the lens drive device when viewed in the optical axis direction.
- the drive magnet is formed in a substantially rectangular prism shape.
- the inner peripheral face of the outer peripheral side magnetic member and the side face of the drive magnet can be disposed to be substantially parallel to each other and thus, as described above, a magnetic flux density passing through the drive coil can be enhanced.
- the movable body is provided with a sleeve which holds a lens holder to which the lens is fixed, and the drive mechanism is provided with one drive coil which is fixed to the sleeve and wound around in a substantially rectangular shape which is longer in a long side direction of the lens drive device when viewed in the optical axis direction.
- the drive mechanism may be provided with two drive coils each of which is wound around in a substantially rectangular tube shape when viewed in the optical axis direction and fixed to the sleeve so that an inner peripheral face of the drive coil faces the side face of the drive magnet through a predetermined gap space.
- FIG. 1 is a perspective view showing a lens drive device for use with at least one lens in accordance with an embodiment of the present invention.
- FIG. 2 is a cross-sectional view showing the lens drive device for use with at least one lens which is cut by the “E-E” line in FIG. 1 .
- FIG. 3 is an exploded perspective view showing the lens drive device for use with at least one lens in FIG. 1 .
- FIG. 4 is a plan view showing the lens drive device for use with at least one lens in FIG. 1 from which a movable body, a flat spring, a base member and the like are detached and which is viewed from an opposite-to-object side.
- FIG. 5 is a cross-sectional view showing the “G-G” cross section in FIG. 4 where an object to be photographed or imaged side is located on an upper side.
- FIG. 6 is an explanatory view showing a structure of a drive coil in accordance with another embodiment of the present invention.
- FIGS. 7(A) and 7(B) are explanatory views showing a schematic structure of a lens drive device for use with at least one lens in accordance with another embodiment of the present invention.
- FIG. 7(A) is an explanatory view showing a schematic structure of the lens drive device which is viewed from an opposite-to-object side
- FIG. 7(B) is a cross-sectional view showing the “H-H” cross section in FIG. 7(A) where an object to be photographed or imaged side is located on an upper side.
- FIGS. 9(A) and 9(B) are explanatory views showing a schematic structure of a lens drive device for use with at least one lens in accordance with another embodiment of the present invention.
- FIG. 9(A) is an explanatory view showing a schematic structure of the lens drive device which is viewed from an opposite-to-object side
- FIG. 9(B) is a cross-sectional view showing the “J-J” cross section in FIG. 9(A) where an object to be photographed or imaged side is located on an upper side.
- FIG. 10 is an enlarged sectional view showing a part of a lens drive device for use with at least one lens in accordance with another embodiment of the present invention.
- FIG. 1 is a perspective view showing a lens drive device for use with at least one lens 1 in accordance with an embodiment of the present invention.
- FIG. 2 is a cross-sectional view showing the lens drive device 1 which is cut by the “E-E” line in FIG. 1 .
- FIG. 3 is an exploded perspective view showing the lens drive device 1 in FIG. 1 .
- three directions perpendicular to each other are set to be “X” direction, “Y” direction and “Z” direction.
- the “X” direction is a right and left direction
- the “Y” direction is a front and rear direction
- the “Z” direction is an up-and-down direction.
- a “Z 1 ” direction side in FIG. 1 is an “upper” side and a “Z 2 ” direction side is a “lower” side.
- a lens drive device 1 for use with at least one lens in this embodiment is mounted on a relatively small camera which is used in a cellular phone, a drive recorder, a monitor camera system or the like.
- the lens drive device 1 is, as shown in FIG. 1 , formed in a roughly rectangular prism shape as a whole.
- the lens drive device 1 is formed in a roughly rectangular shape when viewed in a direction of an optical axis “L” of a lens for photography or imaging including digital images and video for example (optical axis direction).
- the lens drive device 1 is formed in a roughly square shape when viewed in the optical axis direction.
- four side faces of the lens drive device 1 are substantially parallel to the right and left direction or the front and rear direction.
- the “Z” direction (up-and-down direction) is substantially coincided with the optical axis direction.
- an imaging element not shown is disposed on its lower side and an object to be photographed or imaged on an upper side is photographed or imaged.
- the upper side (“Z 1 ” direction side) is an object to be photographed or imaged side (object side)
- the lower side (“Z 2 ” direction side) is an opposite-to-object side (imaging element side, image side).
- the lens drive device 1 is provided with a movable body 2 , which holds a lens for photography or imaging and is movable in the optical axis direction, a fixed body 3 which movably holds or moveable mounts the movable body 2 in the optical axis direction so that the moveable body 2 may move in relation to the fixed body 3 in the optical axis direction, and a drive mechanism 4 for driving the movable body 2 in the optical axis direction.
- the movable body 2 is movably held by the fixed body 3 through flat springs 5 and 6 (see FIG. 2 ). In FIG. 3 , the flat springs 5 and 6 are not shown.
- the movable body 2 is provided with a sleeve 8 which holds a lens holder 7 to which at least one lens or a plurality of lenses is fixed.
- the fixed body 3 is provided with a cover member 10 which structures four side faces (outer peripheral face) of the lens drive device 1 and a base member 11 which structures an end face on an opposite-to-object side of the lens drive device 1 .
- the lens holder 7 is not shown.
- the lens holder 7 is formed in a substantially cylindrical tube shape having a stepped part.
- the at least one or a plurality of lenses whose shape when viewed in the optical axis direction is substantially circular is fixed on an inner peripheral side of the lens holder 7 .
- the sleeve 8 is, for example, formed of resin material and formed in roughly tube-like shape.
- the sleeve 8 holds the lens holder 7 on its inner peripheral side. In other words, an outer peripheral face of the lens holder 7 is fixed to an inner peripheral face of the sleeve 8 .
- the sleeve 8 is formed with two flange parts 8 a and 8 b in a separated state from each other through a predetermined space in the up-and-down direction as shown in FIG. 3 .
- the flange parts 8 a and 8 b are formed so that their external shapes are formed in a substantially square shape.
- the flange part 8 a disposed on the upper side is formed with arrangement holes 8 c within which parts of drive magnets 15 structuring the drive mechanism 4 are disposed are formed so as to penetrate in the up-and-down direction.
- the cover member 10 is formed of magnetic material and formed in a substantially rectangular tube shape with a bottom (substantially bottomed rectangular tube shape) which is provided with a bottom part 10 a and a tube part 10 b .
- the bottom part 10 a is disposed on the upper side and structures an end face on the object to be photographed or imaged side of the lens drive device 1 .
- a circular through hole 10 c is formed at a center of the bottom part 10 a .
- the cover member 10 is disposed so as to surround an outer peripheral side of the drive mechanism 4 and the movable body 2 .
- the base member 11 is formed of resin material and provided with a base part 11 a which is formed in a roughly square-shaped flat plate and standing-up parts 11 b which are stood up toward the upper side from four corners of the base part 11 a .
- a circular through hole 11 c is formed at a center of the base part 11 a .
- the base member 11 is attached to a lower end side of the cover member 10 .
- the flat springs 5 and 6 are structured of a movable body side fixing part which is fixed to the sleeve 8 , fixed body side fixing parts which are fixed to the standing-up parts 11 b of the base member 11 , and spring parts which connect the movable body side fixing part with the fixed body side fixing parts.
- the flat springs 5 and 6 are disposed on a lower side with respect to the flange part 8 b disposed on the lower side.
- the flat spring 5 is fixed to the sleeve 8 , i.e., the under face of the flange part 8 b and the base member 11 in a resiliently bent state so that, when an electric current is not supplied to the drive coil 16 , a reference face formed on an upper face of the base part 11 a and a lower end face of the sleeve 8 are abutted with each other and the movable body 2 is located at a predetermined reference position.
- the drive mechanism 4 is provided with four drive magnets 15 in a substantially triangular prism shape which are disposed at four corners of the lens drive device 1 (specifically, four corners on the inner side of the cover member 10 ) and one drive coil 16 which is wound around on an outer peripheral side of the sleeve 8 .
- the drive mechanism 4 will be described below.
- FIG. 4 is a plan view showing the lens drive device 1 in FIG. 1 from which the movable body 2 , the flat springs 5 and 6 , the base member 11 and the like are detached and which is viewed from an opposite-to-object side.
- FIG. 5 is a cross-sectional view showing the “G-G” cross section in FIG. 4 where an object to be photographed or imaged side is located on an upper side.
- the drive magnet 15 is formed so that its shape when viewed in the up-and-down direction is a substantially rectangular equilateral triangle.
- the drive magnet 15 is provided with two first side faces (first side face) 15 a which are formed in a rectangular shape and are substantially parallel to the optical axis “L” and perpendicular to each other, and one second side face (second side face) 15 b which is formed in a rectangular shape, substantially parallel to the optical axis “L” and connected with the two first side faces 15 a.
- the drive magnet 15 is disposed so that its first side face 15 a faces an inner peripheral face of the tube part 10 b of the cover member 10 through a predetermined space so as to be substantially parallel to each other.
- two drive magnets 15 which are disposed at diagonal positions on the inner side of the cover member 10 are disposed so that their second side faces 15 b are faced each other.
- four drive magnets 15 are fixed to the bottom part 10 a of the cover member 10 .
- upper end faces of the four drive magnets 15 are fixed to an under face of the bottom part 10 a by an adhesive or the like in a state that their upper end faces are abutted with the under face of the bottom part 10 a .
- a lower end face of the drive magnet 15 is fixed with a magnetic member 17 which is formed of magnetic material.
- the magnetic member 17 is formed in a flat plate shape whose shape when viewed in the up-and-down direction is in a substantially rectangular equilateral triangle shape that is similarly to the drive magnet 15 .
- the magnetic member 17 is provided with two first end faces (first end face) 17 a perpendicular to each other and one second end face (second end face) 17 b which is connected with the two first end faces 17 a .
- the magnetic member 17 is fixed to the lower end face of the drive magnet 15 so that its thickness direction is substantially coincided with the up-and-down direction.
- the magnetic member 17 is fixed to the lower end face of the drive magnet 15 so that the first end faces 17 a are disposed to be substantially the same flat faces as the first side faces 15 a of the drive magnet 15 and the second end face 17 b is disposed to be substantially the same flat face as the second side face 15 b of the drive magnet 15 .
- the magnetic member 17 in this embodiment is a second end face side magnetic member which is fixed to the other end face of the drive magnet 15 .
- the drive magnet 15 is magnetized in two poles in the up-and-down direction so that a magnetic pole of the upper end face and a magnetic pole of the lower end face are different from each other.
- the drive magnet 15 is magnetized such that the upper end face of the drive magnet 15 is an “S”-pole and the lower end face of the drive magnet 15 is an “N”-pole. Therefore, as shown in FIG. 5 , in the lens drive device 1 , a magnetic field “F” is formed which passes the tube part 10 b and the bottom part 10 a of the cover member 10 , the drive magnet 15 and the magnetic member 17 to be returned to the inner peripheral face of the tube part 10 b from the under face and the first end face 17 a of the magnetic member 17 .
- a magnetic field “F” is formed which passes the tube part 10 b and the bottom part 10 a of the cover member 10 and the drive magnet 15 to be returned from the lower end face of the drive magnet 15 to the inner peripheral face of the tube part 10 b through the magnetic member 17 .
- the magnetic field “F” is, as shown in FIG. 4 , returned to the inner peripheral face of the tube part 10 b , which is disposed to be substantially parallel to the first side face 15 a of the drive magnet 15 and the first end face 17 a of the magnetic member 17 , from the under face and the first end face 17 a of the magnetic member 17 .
- the drive coil 16 is wound around in a flat and substantially rectangular tube shape whose shape viewed in the up-and-down direction is a substantially square shape. A width of the drive coil 16 in the up-and-down direction is wider than a thickness of the magnetic member 17 .
- the drive coil 16 is fixed to the outer peripheral face of the sleeve 8 . Specifically, the drive coil 16 is fixed between the flange parts 8 a and 8 b of the sleeve 8 and disposed on an outer peripheral side of the arrangement hole 8 c provided in the flange part 8 a by adhesion or the like.
- the drive coil 16 is, as shown in FIG. 4 , disposed along the inner peripheral face of the tube part 10 b of the cover member 10 .
- Four corners and their vicinity portions of the drive coil 16 are disposed within a space between the first side face 15 a of the drive magnet 15 and the first end face 17 a of the magnetic member 17 and the tube part 10 b of the cover member 10 .
- the four corners and their vicinity portions of the drive coil 16 are disposed in the magnetic field “F” which is directed from the under face and the first end face 17 a of the magnetic member 17 to the inner peripheral face of the tube part 10 b .
- the four corners and their vicinity portions of the drive coil 16 are disposed within a space between the first side face 15 a of the drive magnet 15 and the first end face 17 a of the magnetic member 17 and the tube part 10 b of the cover member 10 . Therefore, even when the movable body 2 is moved in the optical axis direction, the drive magnets 15 and the drive coil 16 are not interfered with each other. Accordingly, in this embodiment, even when the lens drive device 1 is made thinner in the up-and-down direction, a stroke of the lens held by the movable body 2 is secured. In other words, in this embodiment, the lens drive device 1 can be made thinner while securing a stroke of the lens.
- the bottom part 10 a with which the upper end face of the drive magnet 15 is abutted is integrally formed with the tube part 10 b . Therefore, magnetic flux is prevented from leaking out from a portion between the bottom part 10 a and the tube part 10 b to the outside of the lens drive device 1 .
- the first side face 15 a of the drive magnet 15 is substantially parallel to the inner peripheral face of the tube part 10 b . Therefore, directions of the magnetic lines of force which are generated by the drive magnet 15 are easily directed to the directions from the under face and the first end face 17 a of the magnetic member 17 toward the inner peripheral face of the tube part 10 b .
- the magnetic flux density which is directed from the under face and the first end face 17 a of the magnetic member 17 to the inner peripheral face of the tube part 10 b , is enhanced.
- the drive magnet 15 and the drive coil 16 are made thinner, a driving force of the drive mechanism 4 is secured and thus the lens drive device 1 can be further made thinner.
- the magnetic member 17 is fixed to the lower end face of the drive magnet 15 and the shape of the drive magnet 15 and the shape of the magnetic member 17 are substantially the same as each other when viewed in the up-and-down direction. According to consideration of the present inventors, when the magnetic member 17 is fixed to the lower end face of the drive magnet 15 , a magnetic flux is concentrated on the magnetic member 17 .
- the density of the magnetic flux which is directed to the inner peripheral face of the tube part 10 b from the under face and the first end face 17 a of the magnetic member 17 is enhanced effectively.
- a driving force of the drive mechanism 4 can be secured.
- the drive magnets 15 are disposed at four corners of the lens drive device 1 whose shape viewed in the optical axis direction is a substantially square shape. Therefore, the drive magnets 15 can be disposed at four corners of the lens drive device 1 which may be dead spaces in the lens drive device 1 that drives the lens whose shape viewed in the optical axis direction is a substantially circular shape. Further, in this embodiment, the drive magnet 15 is formed in a substantially triangular prism shape. Therefore, even when spaces of the four corners of the lens drive device 1 are set to be reduced, the drive magnets 15 can be disposed. Accordingly, in this embodiment, the size of the lens drive device 1 can be reduced.
- FIG. 6 is an explanatory view showing a structure of a drive coil 26 in accordance with another embodiment of the present invention.
- the drive mechanism 4 is provided with one drive coil 16 which is disposed along the inner peripheral face of the tube part 10 b of the cover member 10 .
- the drive mechanism 4 may be provided, instead of the drive coil 16 , with four drive coils 26 as shown in FIG. 6 , each of which is wound around in a substantially triangular tube-like shape and its inner peripheral face is disposed so as to face the side face of the drive magnet 15 through a predetermined gap space.
- the drive coil 26 is wound around so that its shape viewed in the up-and-down direction is a substantially rectangular equilateral triangle shape.
- four drive coils 26 are fixed to the sleeve 8 so that the inner peripheral face of the drive coil 26 and the side face of the drive magnet 15 are substantially parallel to each other with a predetermined gap space therebetween.
- FIGS. 7(A) and 7(B) are explanatory views showing a schematic structure of a lens drive device 1 in accordance with another embodiment of the present invention.
- FIG. 7(A) is an explanatory view showing a schematic structure of the lens drive device 1 which is viewed from an opposite-to-object side
- FIG. 7(B) is a cross-sectional view showing the “H-H” cross section in FIG. 7(A) where an object to be photographed or imaged side is located on an upper side.
- FIG. 8 is an explanatory view showing a schematic structure of a lens drive device 1 in accordance with another embodiment of the present invention which is viewed from an opposite-to-object side.
- the lens drive device 1 is formed so that its shape viewed in the optical axis direction is a substantially square shape. Further, the drive magnet 15 formed in a substantially triangular prism shape is disposed at four corners of the lens drive device 1 .
- the present invention is not limited to this embodiment.
- the lens drive device 1 may be formed so that its shape viewed in the optical axis direction is a substantially rectangular shape.
- a drive magnet 35 may be formed in a substantially rectangular prism shape and disposed on both sides of the lens drive device in a direction substantially parallel to a long side of the lens drive device 1 when viewed in the optical axis direction.
- the lens drive device 1 in accordance with the second modified embodiment is provided with a sleeve 38 corresponding to the sleeve 8 of the embodiment described above and a cover member 30 corresponding to the cover member 10 .
- the drive magnet 35 is formed in a substantially rectangular shape whose shape viewed in the up-and-down direction is elongated in a short side direction of the lens drive device 1 .
- the drive magnet 35 is disposed so that its three side faces 35 a and an inner peripheral face of the tube part 30 b of the cover member 30 are substantially parallel and faced to each other with a predetermined space therebetween. Further, the drive magnet 35 is fixed to an under face of the bottom part 30 a of the cover member 30 in an abutted state. A lower end face of the drive magnet 35 is fixed to a magnetic member 37 which is formed of magnetic material.
- the drive magnet 35 is magnetized in two poles in the up-and-down direction so that a magnetic pole of the upper end face and a magnetic pole of the lower end face are different from each other. Therefore, as shown in FIG. 7(B) , in the lens drive device 1 in accordance with the second modified embodiment, a magnetic field “F” is formed which passes the tube part 30 b and the bottom part 30 a of the cover member 30 , the drive magnet 35 and the magnetic member 37 to be returned to the inner peripheral face of the tube part 30 b from the under face and the end face of the magnetic member 37 .
- a magnetic field “F” is formed which passes the tube part 30 b and the bottom part 30 a of the cover member 30 and the drive magnet 35 to be returned from the lower end face of the drive magnet 35 to the inner peripheral face of the tube part 30 b through the magnetic member 37 .
- the magnetic field “F” is, as shown in FIG. 7(A) , directed from the under face and the end face of the magnetic member 37 to the inner peripheral face of the tube part 30 b which is disposed so as to be substantially parallel and faced to the three side faces 35 a of the drive magnet 35 .
- the magnetic field “F” is also returned to the inner peripheral face of the tube part 30 b from the vicinity of abutting part of the lower end face of the drive magnet 35 with the upper face of the magnetic member 37 .
- a drive coil 36 is wound around so that its shape viewed in the up-and-down direction is a substantially rectangular shape which is elongated in a long side direction of the lens drive device 1 .
- the drive coil 36 is provided with short side parts 36 a and long side parts 36 b which are longer than the short side part 36 a .
- the drive coil 36 is fixed to an outer peripheral face of the sleeve 38 so as to be along the inner peripheral face of the tube part 30 b .
- Both end sides of the long side parts 36 b and the short side part 36 a of the drive coil 36 are disposed within a space between three side faces 35 a of the drive magnet 35 and the inner peripheral face of the tube part 30 b .
- the both end sides of the long side parts 36 b and the short side part 36 a are disposed within the magnetic field “F” which is directed from the under face and the end faces of the magnetic member 37 to the inner peripheral face of the tube part 30 b.
- the drive magnets 35 are disposed on both sides of the lens drive device 1 in a direction substantially parallel to the long side of the lens drive device 1 when viewed in the optical axis direction. Therefore, the size of the lens drive device 1 can be further reduced in a direction substantially parallel to the short side of the lens drive device 1 when viewed in the optical axis direction.
- the drive coil 36 instead of the drive coil 36 , as shown in FIG.
- two drive coils 46 which are wound around in a substantially rectangular tube shape and whose inner peripheral side is disposed so as to face the side face of the drive magnet 35 through a predetermined space are fixed to an outer peripheral face of the sleeve 38 .
- FIGS. 9(A) and 9(B) are explanatory views showing a schematic structure of a lens drive device 1 in accordance with another embodiment of the present invention.
- FIG. 9(A) is an explanatory view showing a schematic structure of the lens drive device 1 which is viewed from an opposite-to-object side
- FIG. 9(B) is a cross-sectional view showing the “J-J” cross section in FIG. 9(A) where an object to be photographed or imaged side is located on an upper side.
- the drive magnet 15 which is formed in a substantially triangular prism shape is disposed at four corners of the lens drive device 1 .
- the present invention is not limited to this embodiment.
- a drive magnet 55 which is formed in a substantially rectangular plate shape may be disposed on each of four side faces of the lens drive device 1 .
- the drive magnet 55 is disposed so that its one side face 55 a and an inner peripheral face of a tube part 10 b of a cover member 10 are in substantially parallel and faced to each other with a predetermined space therebetween. Further, the drive magnet 55 is fixed to an under face of a bottom part 10 a of the cover member 10 in an abutted state. A lower end face of the drive magnet 55 is fixed to a magnetic member 57 which is formed of magnetic material. The magnetic member 57 is formed in a flat plate-like shape which is, similarly to the drive magnet 55 , substantially rectangular shape when viewed in the up-and-down direction. In the third modified embodiment, the magnetic member 57 is a second end face side magnetic member which is fixed to the other end face of the drive magnet 55 .
- the drive magnet 55 is magnetized in two poles in the up-and-down direction so that a magnetic pole of the upper end face and a magnetic pole of the lower end face are different from each other. Therefore, similarly to the above-mentioned embodiment, in the lens drive device 1 in accordance with the third modified embodiment, a magnetic field “F” is formed which passes the tube part 10 b and the bottom part 10 a , the drive magnet 55 and the magnetic member 57 to be returned to the inner peripheral face of the tube part 10 b from the under face and the end face of the magnetic member 57 .
- the magnetic field “F” is, as shown in FIG.
- the magnetic field “F” is also returned to the inner peripheral face of the tube part 10 b from the vicinity of abutting part of the lower end face of the drive magnet 55 with the upper face of the magnetic member 57 .
- a part of the drive coil 16 is disposed within a space between the side face 55 a of the drive magnet 55 and the inner peripheral face of the tube part 10 b . Further, the part of the drive coil 16 is disposed in the magnetic field “F” which is directed from the under face and the end face of the magnetic member 57 to the inner peripheral face of the tube part 10 b . Also in the third modified embodiment, effects similar to the above-mentioned embodiment can be obtained.
- FIG. 10 is an enlarged sectional view showing a part of a lens drive device 1 in accordance with another embodiment of the present invention.
- the upper end face of the drive magnet 15 is fixed to the under face of the bottom part 10 a in an abutted state with the under face of the bottom part 10 a .
- the present invention is not limited to this embodiment.
- a magnetic member 67 may be formed so that an end face 67 a of the magnetic member 67 which is fixed to a lower end face of the drive magnet 15 is abutted with an inner peripheral face of a tube part 72 of a cover member 70 .
- the end face 67 a is fixed to the inner peripheral face of the tube part 72 and a space is formed between an upper end face of the drive magnet 15 and a bottom part 71 of the cover member 70 .
- a magnetic field “F” which is directed from the inner peripheral face of the tube part 72 to an upper end face of the drive magnet 15 is formed and thus four corners and their vicinity portions of the drive coil 16 are disposed in the magnetic field “F” which is directed from the inner peripheral face of the tube part 72 to the upper end face of the drive magnet 15 .
- the cover member 70 may be preferably structured of a bottom part 71 made of nonmagnetic material and a tube part 72 made of magnetic material so that magnetic lines of force generated from the drive magnet 15 are not directed from the bottom part 71 to the upper end face of the drive magnet 15 .
- the lens drive device 1 may be provided with four magnetic members 67 to which respective four drive magnets 15 are fixed, or one magnetic member 67 to which all of four drive magnets 15 are fixed. Also in the fourth modified embodiment, effects similar to the above-mentioned embodiment can be obtained.
- the magnetic member 67 is an end face side magnetic member to which one end face of the drive magnet 15 is fixed
- the tube part 72 is an outer peripheral side magnetic member which structures the outer peripheral face of the fixed body 3 .
- a magnetic member is not fixed to the upper end face of the drive magnet 15 but a magnetic member may be fixed to the upper end face of the drive magnet 15 .
- the magnetic member is a second end face side magnetic member.
- the magnetic member 17 is fixed to the lower end face of the drive magnet 15 but no magnetic member 17 is fixed to the lower end face of the drive magnet 15 .
- a length of the drive magnet 15 is capable of being increased in the up-and-down direction by a thickness of the magnetic member 17 and thus a driving force of the drive mechanism 4 can be enhanced.
- the magnetic member 17 is not required to be fixed to a lower end face of the drive magnet 15 and thus assembling steps for the lens drive device 1 can be simplified.
- the cover member 10 is structured of the bottom part 10 a and the tube part 10 b , and the bottom part 10 a and the tube part 10 b are formed in an integral manner.
- the present invention is not limited to this embodiment.
- the bottom part made of magnetic material and the tube part made of magnetic material may be formed of separate members.
- the end face of the bottom part and the inner peripheral face of the tube part may be abutted with each other, or a gap space may be formed between the end face of the bottom part and the inner peripheral face of the tube part.
- the under face of the bottom part and the upper end face of the tube part may be abutted with each other, or a gap space may be formed between the under face of the bottom part and the upper end face of the tube part.
- the end face of the bottom part and the inner peripheral face of the tube part are abutted with each other, or the under face of the bottom part and the upper end face of the tube part are abutted with each other.
- the drive magnet 15 is formed in a substantially triangular prism shape, but the drive magnet 15 may be formed in a polygonal prism shape other than a substantially triangular prism shape or may be formed in a substantially circular cylinder shape or a substantially elliptical cylinder shape.
- the lens drive device 1 is formed in a roughly quadrangular shape when viewed in the optical axis direction.
- the lens drive device 1 may be formed in a roughly polygonal shape other than a roughly rectangular shape when viewed in the optical axis direction or may be formed in a roughly circular shape or elliptical shape when viewed in the optical axis direction.
- the drive coil 16 may be wound around, for example, in a cylindrical tube shape or the like depending on the shape of the lens drive device 1 and the shape of the drive magnet 15 when viewed in the optical axis direction.
- the drive coil 26 in the first modified embodiment may be also wound around, for example, in a cylindrical tube shape or the like depending on the shape of the lens drive device 1 and the shape of the drive magnet 15 when viewed in the optical axis direction.
- the shape of the drive magnet 15 when viewed in the up-and-down direction is substantially the same as the shape of the magnetic member 17 .
- the shape of the drive magnet 15 when viewed in the up-and-down direction may be different from the shape of the magnetic member 17 .
- the drive magnet 15 is disposed at four corners of the lens drive device 1 .
- the drive magnet 15 may be disposed at three corners, two corners or only one corner of the four corners of the lens drive device 1 .
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Abstract
Description
- The present invention claims priority under 35 U.S.C. §119 to Japanese Application No. 2010-70526 filed Mar. 25, 2010, the entire content of which is incorporated herein by reference.
- At least an embodiment of the present invention may relate to a lens drive device for use with at least one lens which is used in a relatively small camera that is mounted on a cellular phone or the like.
- A lens drive device has been conventionally known in which a photographing lens for a camera that is mounted on a cellular phone or the like is driven. The lens drive device is provided with a lens holder, which holds a plurality of lenses and is moved in an optical axis direction, and a drive mechanism part for driving the lens holder in the optical axis direction (see, for example, Japanese Patent Laid-Open No. 2009-198948). In the lens drive device described in this Patent Literature, a drive coil which is wound around in a square shape is fixed to an outer peripheral side of the lens holder and two drive magnets are disposed so as to interpose the drive coil from both sides in the optical axis direction.
- In recent years, in a market of a camera which is mounted on a cellular phone or the like, requirement for making a camera thinner has been further increased and, in order to meet the requirement, requirement for making a lens drive device used in a camera thinner has been also increased. However, in the lens drive device described in the above-mentioned Patent Literature, two drive magnets are disposed so as to interpose the drive coil which is fixed to the lens holder from both sides in the optical axis direction. Therefore, when the device is made thinner, a space in the optical axis direction between two drive magnets becomes narrow. As a result, in the lens drive device, when the device is made thinner, it is difficult to secure a required stroke of the lens.
- In view of the problem described above, at least an embodiment of the present invention may advantageously provide a lens drive device which is capable of being made thinner in the optical axis direction while securing a stroke of the lens.
- According to at least an embodiment of the present invention, there may be provided a lens drive device including a movable body which holds a lens and is movable in an optical axis direction of the lens, a fixed body which movably holds the movable body in the optical axis direction, and a drive mechanism for driving the movable body in the optical axis direction. The drive mechanism includes a drive coil which is fixed to the movable body, and a plurality of drive magnets which is formed in a substantially columnar shape or a substantially plate shape and fixed to the fixed body, and the drive magnet is magnetized so that a magnetic pole of one end face is different from a magnetic pole of the other end face in the optical axis direction. The fixed body includes an outer peripheral side magnetic member, which is formed of magnetic material and formed in a substantially tube-like shape and structures an outer peripheral face of the fixed body, and an end face side magnetic member which is formed of magnetic material and to which the one end face of the drive magnet is fixed. An inner peripheral face of the outer peripheral side magnetic member and a side face of the drive magnet are faced each other through a predetermined space. The outer peripheral side magnetic member, the end face side magnetic member and the drive magnet are disposed so that a magnetic field is formed so as to pass through the drive magnet, the end face side magnetic member and the outer peripheral side magnetic member and returned to the other end face of the drive magnet from the inner peripheral face of the outer peripheral side magnetic member, or returned to the inner peripheral face of the outer peripheral side magnetic member from the other end face of the drive magnet, and the drive coil is disposed between the other end face side of the drive magnet and the inner peripheral face of the outer peripheral side magnetic member.
- In the lens drive device for use with at least one lens in accordance with an embodiment of the present invention, an inner peripheral face of the outer peripheral side magnetic member which is formed in a substantially tube-like shape and structures an outer peripheral face of the fixed body is disposed so as to face a side face of the drive magnet which is formed in a substantially columnar shape or a substantially plate shape through a predetermined space and the drive coil is disposed between the other end face side of the drive magnet in the optical axis direction and the inner peripheral face of the outer peripheral side magnetic member. Therefore, even when the movable body is moved in the optical axis direction, the drive magnet and the drive coil are not interfered with each other. Accordingly, even when the lens drive device is made thinner in the optical axis direction, a stroke of the movable body in the optical axis direction, in other words, a stroke of the lens in the optical axis direction is secured. In other words, in accordance with the embodiment of the present invention, the lens drive device is made thinner while securing a stroke of the lens.
- In accordance with an embodiment of the present invention, the outer peripheral side magnetic member and the end face side magnetic member are formed in an integral manner. In this case, for example, the fixed body is provided with a cover member which is formed in a substantially bottomed tube-like shape in which the end face side magnetic member is a bottom part and the outer peripheral side magnetic member is a tube part that is integrally formed with the bottom part, and the end face side magnetic member structures an end face on an object to be photographed or imaged side of the lens drive device. According to this structure, leakage of a magnetic flux from a portion between the end face side magnetic member and the outer peripheral side magnetic member is prevented. Therefore, a magnetic flux density passing through the drive coil which is disposed between the other end face side of the drive magnet and the inner peripheral face of the outer peripheral side magnetic member is enhanced. As a result, even when the drive magnet and the drive coil are made thinner, a driving force of the drive mechanism is secured and thus the lens drive device can be further made thinner.
- In accordance with an embodiment of the present invention, an end face of the end face side magnetic member is abutted with the inner peripheral face of the outer peripheral side magnetic member. According to this structure, leakage of a magnetic flux from a portion between the end face side magnetic member and the outer peripheral side magnetic member is restrained and thus a magnetic flux density passing through the drive coil is enhanced. Therefore, even when the drive magnet and the drive coil are made thinner, a driving force of the drive mechanism is secured.
- In accordance with an embodiment of the present invention, the inner peripheral face of the outer peripheral side magnetic member and the side face of the drive magnet which are faced each other are substantially parallel to each other. According to this structure, directions of magnetic lines of force generated from the drive magnet are easily directed from the other end face of the drive magnet to the inner peripheral face of the outer peripheral side magnetic member, or easily directed from the inner peripheral face of the outer peripheral side magnetic member to the other end face of the drive magnet and thus a magnetic flux density passing through the drive coil is enhanced. Therefore, even when the drive magnet and the drive coil are made thinner, a driving force of the drive mechanism is secured.
- In accordance with an embodiment of the present invention, the other end face of the drive magnet is fixed with a second end face side magnetic member which is formed of magnetic material, and the magnetic field is directed from the inner peripheral face of the outer peripheral side magnetic member to the other end face of the drive magnet through the second end face side magnetic member, or the magnetic field is directed from the other end face of the drive magnet to the inner peripheral face of the outer peripheral side magnetic member through the second end face side magnetic member. When the second end face side magnetic member is fixed to the other end face of the drive magnet, a magnetic flux is concentrated on the second end face side magnetic member. Therefore, according to this structure, a magnetic flux density passing through the drive coil is enhanced. In this case, it is preferable that a width in the optical axis direction of the drive coil is set to be a width in which the second end face side magnetic member is always located and faced on an inner peripheral side of the drive coil over a moving range of the movable body.
- In accordance with an embodiment of the present invention, a shape of the drive magnet when viewed in the optical axis direction is substantially the same as a shape of the second end face side magnetic member when viewed in the optical axis direction. In comparison with a case that a shape of the drive magnet when viewed in the optical axis direction is different from a shape of the second end face side magnetic member when viewed in the optical axis direction, when the shape of the drive magnet when viewed in the optical axis direction is substantially the same as the shape of the second end face side magnetic member when viewed in the optical axis direction, directions of magnetic lines of force generated from the drive magnet are easily directed from the other end face of the drive magnet to the inner peripheral face of the outer peripheral side magnetic member, or easily directed from the inner peripheral face of the outer peripheral side magnetic member to the other end face of the drive magnet. Therefore, according to this structure, a magnetic flux density passing through the drive coil is further enhanced.
- In accordance with an embodiment of the present invention, the drive mechanism is provided with one drive coil which is wound around in a tube-like shape and disposed along the inner peripheral face of the outer peripheral side magnetic member. According to this structure, in comparison with a case that a plurality of drive coils is disposed so as to correspond to a plurality of drive magnets, a structure of the lens drive device is simplified. Further, according to this structure, in comparison with a case that a plurality of drive coils is disposed, handling of end parts of a conducting wire structuring the drive coil is simplified and thus manufacturing steps for the lens drive device are simplified. Specifically, it may be structured that the movable body is provided with a sleeve which holds a lens holder to which the lens is fixed, the sleeve is formed with two flange parts which are separated from each other through a predetermined space in the optical axis direction, the flange part which is disposed on a side of the end face side magnetic member is formed with an arrangement hole within which a part of the drive magnet is disposed, and the drive coil is fixed between the two flange parts of the sleeve so as to be fixed on an outer peripheral side of the arrangement hole.
- In accordance with an embodiment of the present invention, a shape of the lens drive device when viewed in the optical axis direction is formed in a substantially square shape or a substantially rectangular shape, and the drive magnet is disposed at four corners of the lens drive device. In this case, the drive magnet may be disposed at four corners of the lens drive device which is liable to be dead spaces. Therefore, the size of the lens drive device whose shape when viewed in the optical axis direction is formed in a substantially square shape or a substantially rectangular shape can be reduced.
- Further, in this case, it is preferable that the drive magnet is formed in a substantially triangular prism shape. According to this structure, even when spaces of four corners of the lens drive device are made relatively small, the drive magnet is disposed at four corners of the lens drive device. Therefore, the size of the lens drive device can be further reduced. Further, according to this structure, the inner peripheral face of the outer peripheral side magnetic member and the side face of the drive magnet can be disposed to be substantially parallel to each other and thus, as described above, a magnetic flux density passing through the drive coil can be enhanced. In this case, the drive mechanism may be provided with one drive coil which is wound around in a tube-like shape and disposed along the inner peripheral face of the outer peripheral side magnetic member, or the drive mechanism may be provided with four drive coils each of which is wound around in a substantially triangular tube-like shape and faces the side face of the drive magnet through a predetermined gap space.
- In accordance with an embodiment of the present invention, a shape of the lens drive device for use with at least one lens when viewed in the optical axis direction is formed in a substantially rectangular shape, and the drive magnet is disposed on both sides of the lens drive device in a direction substantially parallel to a long side of the lens drive device when viewed in the optical axis direction. In this case, the size of the lens drive device is further reduced in a direction substantially parallel to a short side of the lens drive device when viewed in the optical axis direction.
- Further, in this case, it is preferable that the drive magnet is formed in a substantially rectangular prism shape. According to this structure, the inner peripheral face of the outer peripheral side magnetic member and the side face of the drive magnet can be disposed to be substantially parallel to each other and thus, as described above, a magnetic flux density passing through the drive coil can be enhanced. In this case, specifically, it may be structured that the movable body is provided with a sleeve which holds a lens holder to which the lens is fixed, and the drive mechanism is provided with one drive coil which is fixed to the sleeve and wound around in a substantially rectangular shape which is longer in a long side direction of the lens drive device when viewed in the optical axis direction. Alternatively, the drive mechanism may be provided with two drive coils each of which is wound around in a substantially rectangular tube shape when viewed in the optical axis direction and fixed to the sleeve so that an inner peripheral face of the drive coil faces the side face of the drive magnet through a predetermined gap space.
- Other features and advantages of the invention will be apparent from the following detailed description, taken in conjunction with the accompanying drawings that illustrate, by way of example, various features of embodiments of the invention.
- Embodiments will now be described, by way of example only, with reference to the accompanying drawings which are meant to be exemplary, not limiting, and wherein like elements are numbered alike in several Figures, in which:
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FIG. 1 is a perspective view showing a lens drive device for use with at least one lens in accordance with an embodiment of the present invention. -
FIG. 2 is a cross-sectional view showing the lens drive device for use with at least one lens which is cut by the “E-E” line inFIG. 1 . -
FIG. 3 is an exploded perspective view showing the lens drive device for use with at least one lens inFIG. 1 . -
FIG. 4 is a plan view showing the lens drive device for use with at least one lens inFIG. 1 from which a movable body, a flat spring, a base member and the like are detached and which is viewed from an opposite-to-object side. -
FIG. 5 is a cross-sectional view showing the “G-G” cross section inFIG. 4 where an object to be photographed or imaged side is located on an upper side. -
FIG. 6 is an explanatory view showing a structure of a drive coil in accordance with another embodiment of the present invention. -
FIGS. 7(A) and 7(B) are explanatory views showing a schematic structure of a lens drive device for use with at least one lens in accordance with another embodiment of the present invention.FIG. 7(A) is an explanatory view showing a schematic structure of the lens drive device which is viewed from an opposite-to-object side andFIG. 7(B) is a cross-sectional view showing the “H-H” cross section inFIG. 7(A) where an object to be photographed or imaged side is located on an upper side. -
FIG. 8 is an explanatory view showing a schematic structure of a lens drive device for use with at least one lens in accordance with another embodiment of the present invention which is viewed from an opposite-to-object side. -
FIGS. 9(A) and 9(B) are explanatory views showing a schematic structure of a lens drive device for use with at least one lens in accordance with another embodiment of the present invention.FIG. 9(A) is an explanatory view showing a schematic structure of the lens drive device which is viewed from an opposite-to-object side andFIG. 9(B) is a cross-sectional view showing the “J-J” cross section inFIG. 9(A) where an object to be photographed or imaged side is located on an upper side. -
FIG. 10 is an enlarged sectional view showing a part of a lens drive device for use with at least one lens in accordance with another embodiment of the present invention. - An embodiment of the present invention will be described below with reference to the accompanying drawings.
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FIG. 1 is a perspective view showing a lens drive device for use with at least onelens 1 in accordance with an embodiment of the present invention.FIG. 2 is a cross-sectional view showing thelens drive device 1 which is cut by the “E-E” line inFIG. 1 .FIG. 3 is an exploded perspective view showing thelens drive device 1 inFIG. 1 . In the following description, as shown inFIG. 1 and the like, three directions perpendicular to each other are set to be “X” direction, “Y” direction and “Z” direction. The “X” direction is a right and left direction, the “Y” direction is a front and rear direction, and the “Z” direction is an up-and-down direction. Further, a “Z1” direction side inFIG. 1 is an “upper” side and a “Z2” direction side is a “lower” side. - A
lens drive device 1 for use with at least one lens in this embodiment is mounted on a relatively small camera which is used in a cellular phone, a drive recorder, a monitor camera system or the like. Thelens drive device 1 is, as shown inFIG. 1 , formed in a roughly rectangular prism shape as a whole. In other words, thelens drive device 1 is formed in a roughly rectangular shape when viewed in a direction of an optical axis “L” of a lens for photography or imaging including digital images and video for example (optical axis direction). In this embodiment, thelens drive device 1 is formed in a roughly square shape when viewed in the optical axis direction. Further, four side faces of thelens drive device 1 are substantially parallel to the right and left direction or the front and rear direction. - In this embodiment, the “Z” direction (up-and-down direction) is substantially coincided with the optical axis direction. Further, in the camera on which the
lens drive device 1 in this embodiment is mounted, an imaging element not shown is disposed on its lower side and an object to be photographed or imaged on an upper side is photographed or imaged. In other words, in this embodiment, the upper side (“Z1” direction side) is an object to be photographed or imaged side (object side) and the lower side (“Z2” direction side) is an opposite-to-object side (imaging element side, image side). - As shown in
FIGS. 1 and 2 , thelens drive device 1 is provided with a movable body 2, which holds a lens for photography or imaging and is movable in the optical axis direction, afixed body 3 which movably holds or moveable mounts the movable body 2 in the optical axis direction so that the moveable body 2 may move in relation to the fixedbody 3 in the optical axis direction, and adrive mechanism 4 for driving the movable body 2 in the optical axis direction. The movable body 2 is movably held by the fixedbody 3 through flat springs 5 and 6 (seeFIG. 2 ). InFIG. 3 , theflat springs 5 and 6 are not shown. - The movable body 2 is provided with a
sleeve 8 which holds alens holder 7 to which at least one lens or a plurality of lenses is fixed. The fixedbody 3 is provided with acover member 10 which structures four side faces (outer peripheral face) of thelens drive device 1 and abase member 11 which structures an end face on an opposite-to-object side of thelens drive device 1. InFIG. 3 , thelens holder 7 is not shown. - The
lens holder 7 is formed in a substantially cylindrical tube shape having a stepped part. The at least one or a plurality of lenses whose shape when viewed in the optical axis direction is substantially circular is fixed on an inner peripheral side of thelens holder 7. Thesleeve 8 is, for example, formed of resin material and formed in roughly tube-like shape. Thesleeve 8 holds thelens holder 7 on its inner peripheral side. In other words, an outer peripheral face of thelens holder 7 is fixed to an inner peripheral face of thesleeve 8. Further, thesleeve 8 is formed with twoflange parts FIG. 3 . Theflange parts flange part 8 a disposed on the upper side is formed witharrangement holes 8 c within which parts ofdrive magnets 15 structuring thedrive mechanism 4 are disposed are formed so as to penetrate in the up-and-down direction. - The
cover member 10 is formed of magnetic material and formed in a substantially rectangular tube shape with a bottom (substantially bottomed rectangular tube shape) which is provided with abottom part 10 a and atube part 10 b. Thebottom part 10 a is disposed on the upper side and structures an end face on the object to be photographed or imaged side of thelens drive device 1. A circular throughhole 10 c is formed at a center of thebottom part 10 a. Thecover member 10 is disposed so as to surround an outer peripheral side of thedrive mechanism 4 and the movable body 2. - The
base member 11 is formed of resin material and provided with abase part 11 a which is formed in a roughly square-shaped flat plate and standing-upparts 11 b which are stood up toward the upper side from four corners of thebase part 11 a. A circular throughhole 11 c is formed at a center of thebase part 11 a. Thebase member 11 is attached to a lower end side of thecover member 10. - The
flat springs 5 and 6 are structured of a movable body side fixing part which is fixed to thesleeve 8, fixed body side fixing parts which are fixed to the standing-upparts 11 b of thebase member 11, and spring parts which connect the movable body side fixing part with the fixed body side fixing parts. Theflat springs 5 and 6 are disposed on a lower side with respect to theflange part 8 b disposed on the lower side. In this embodiment, the flat spring 5 is fixed to thesleeve 8, i.e., the under face of theflange part 8 b and thebase member 11 in a resiliently bent state so that, when an electric current is not supplied to thedrive coil 16, a reference face formed on an upper face of thebase part 11 a and a lower end face of thesleeve 8 are abutted with each other and the movable body 2 is located at a predetermined reference position. - The
drive mechanism 4 is provided with fourdrive magnets 15 in a substantially triangular prism shape which are disposed at four corners of the lens drive device 1 (specifically, four corners on the inner side of the cover member 10) and onedrive coil 16 which is wound around on an outer peripheral side of thesleeve 8. A detailed structure of thedrive mechanism 4 will be described below. -
FIG. 4 is a plan view showing thelens drive device 1 inFIG. 1 from which the movable body 2, theflat springs 5 and 6, thebase member 11 and the like are detached and which is viewed from an opposite-to-object side.FIG. 5 is a cross-sectional view showing the “G-G” cross section inFIG. 4 where an object to be photographed or imaged side is located on an upper side. - The
drive magnet 15 is formed so that its shape when viewed in the up-and-down direction is a substantially rectangular equilateral triangle. Thedrive magnet 15 is provided with two first side faces (first side face) 15 a which are formed in a rectangular shape and are substantially parallel to the optical axis “L” and perpendicular to each other, and one second side face (second side face) 15 b which is formed in a rectangular shape, substantially parallel to the optical axis “L” and connected with the two first side faces 15 a. - The
drive magnet 15 is disposed so that its first side face 15 a faces an inner peripheral face of thetube part 10 b of thecover member 10 through a predetermined space so as to be substantially parallel to each other. In other words, twodrive magnets 15 which are disposed at diagonal positions on the inner side of thecover member 10 are disposed so that their second side faces 15 b are faced each other. Further, fourdrive magnets 15 are fixed to thebottom part 10 a of thecover member 10. Specifically, upper end faces of the fourdrive magnets 15 are fixed to an under face of thebottom part 10 a by an adhesive or the like in a state that their upper end faces are abutted with the under face of thebottom part 10 a. Further, the upper end face of each of the fourdrive magnets 15 is completely covered by thebottom part 10 a. Thebottom part 10 a in this embodiment is an end face side magnetic member to which one end face of each of thedrive magnets 15 is fixed, and thetube part 10 b is an outer peripheral side magnetic member which structures the outer peripheral face of the fixedbody 3. - A lower end face of the
drive magnet 15 is fixed with amagnetic member 17 which is formed of magnetic material. Themagnetic member 17 is formed in a flat plate shape whose shape when viewed in the up-and-down direction is in a substantially rectangular equilateral triangle shape that is similarly to thedrive magnet 15. Themagnetic member 17 is provided with two first end faces (first end face) 17 a perpendicular to each other and one second end face (second end face) 17 b which is connected with the two first end faces 17 a. Themagnetic member 17 is fixed to the lower end face of thedrive magnet 15 so that its thickness direction is substantially coincided with the up-and-down direction. Further, themagnetic member 17 is fixed to the lower end face of thedrive magnet 15 so that the first end faces 17 a are disposed to be substantially the same flat faces as the first side faces 15 a of thedrive magnet 15 and thesecond end face 17 b is disposed to be substantially the same flat face as thesecond side face 15 b of thedrive magnet 15. Themagnetic member 17 in this embodiment is a second end face side magnetic member which is fixed to the other end face of thedrive magnet 15. - The
drive magnet 15 is magnetized in two poles in the up-and-down direction so that a magnetic pole of the upper end face and a magnetic pole of the lower end face are different from each other. For example, thedrive magnet 15 is magnetized such that the upper end face of thedrive magnet 15 is an “S”-pole and the lower end face of thedrive magnet 15 is an “N”-pole. Therefore, as shown inFIG. 5 , in thelens drive device 1, a magnetic field “F” is formed which passes thetube part 10 b and thebottom part 10 a of thecover member 10, thedrive magnet 15 and themagnetic member 17 to be returned to the inner peripheral face of thetube part 10 b from the under face and thefirst end face 17 a of themagnetic member 17. In other words, in thelens drive device 1, a magnetic field “F” is formed which passes thetube part 10 b and thebottom part 10 a of thecover member 10 and thedrive magnet 15 to be returned from the lower end face of thedrive magnet 15 to the inner peripheral face of thetube part 10 b through themagnetic member 17. The magnetic field “F” is, as shown inFIG. 4 , returned to the inner peripheral face of thetube part 10 b, which is disposed to be substantially parallel to the first side face 15 a of thedrive magnet 15 and thefirst end face 17 a of themagnetic member 17, from the under face and thefirst end face 17 a of themagnetic member 17. The magnetic field “F” is also returned to the inner peripheral face of thetube part 10 b from the vicinity of the abutting part of the lower end face of thedrive magnet 15 with the upper face of themagnetic member 17 but the magnetic field “F” is not shown inFIG. 5 . - The
drive coil 16 is wound around in a flat and substantially rectangular tube shape whose shape viewed in the up-and-down direction is a substantially square shape. A width of thedrive coil 16 in the up-and-down direction is wider than a thickness of themagnetic member 17. Thedrive coil 16 is fixed to the outer peripheral face of thesleeve 8. Specifically, thedrive coil 16 is fixed between theflange parts sleeve 8 and disposed on an outer peripheral side of thearrangement hole 8 c provided in theflange part 8 a by adhesion or the like. - The
drive coil 16 is, as shown inFIG. 4 , disposed along the inner peripheral face of thetube part 10 b of thecover member 10. Four corners and their vicinity portions of thedrive coil 16 are disposed within a space between the first side face 15 a of thedrive magnet 15 and thefirst end face 17 a of themagnetic member 17 and thetube part 10 b of thecover member 10. Further, as shown inFIG. 5 , the four corners and their vicinity portions of thedrive coil 16 are disposed in the magnetic field “F” which is directed from the under face and thefirst end face 17 a of themagnetic member 17 to the inner peripheral face of thetube part 10 b. In this embodiment, thedrive coil 16 is disposed so that themagnetic member 17 is always disposed on the inner peripheral side of thedrive coil 16 over a moving range of the movable body 2. In other words, a width in the up-and-down direction (optical axis direction) of thedrive coil 16 is set so that, over the moving range of the movable body 2, the lower end face of thedrive coil 16 is not moved to the upper side with respect to the under face of themagnetic member 17 and, in addition, the upper end face of thedrive coil 16 is not moved to the lower side with respect to the upper face of themagnetic member 17. When an electric current is supplied to thedrive coil 16, the movable body 2 is moved in the up-and-down direction (optical axis direction) by an operation between thedrive magnets 15 and thedrive coil 16. - As described above, in this embodiment, the four corners and their vicinity portions of the
drive coil 16 are disposed within a space between the first side face 15 a of thedrive magnet 15 and thefirst end face 17 a of themagnetic member 17 and thetube part 10 b of thecover member 10. Therefore, even when the movable body 2 is moved in the optical axis direction, thedrive magnets 15 and thedrive coil 16 are not interfered with each other. Accordingly, in this embodiment, even when thelens drive device 1 is made thinner in the up-and-down direction, a stroke of the lens held by the movable body 2 is secured. In other words, in this embodiment, thelens drive device 1 can be made thinner while securing a stroke of the lens. - In this embodiment, the
bottom part 10 a with which the upper end face of thedrive magnet 15 is abutted is integrally formed with thetube part 10 b. Therefore, magnetic flux is prevented from leaking out from a portion between thebottom part 10 a and thetube part 10 b to the outside of thelens drive device 1. Further, in this embodiment, the first side face 15 a of thedrive magnet 15 is substantially parallel to the inner peripheral face of thetube part 10 b. Therefore, directions of the magnetic lines of force which are generated by thedrive magnet 15 are easily directed to the directions from the under face and thefirst end face 17 a of themagnetic member 17 toward the inner peripheral face of thetube part 10 b. Accordingly, in this embodiment, the magnetic flux density which is directed from the under face and thefirst end face 17 a of themagnetic member 17 to the inner peripheral face of thetube part 10 b, (in other words, magnetic flux density passing through the drive coil 16) is enhanced. As a result, in this embodiment, even when thedrive magnet 15 and thedrive coil 16 are made thinner, a driving force of thedrive mechanism 4 is secured and thus thelens drive device 1 can be further made thinner. - Especially, in this embodiment, the
magnetic member 17 is fixed to the lower end face of thedrive magnet 15 and the shape of thedrive magnet 15 and the shape of themagnetic member 17 are substantially the same as each other when viewed in the up-and-down direction. According to consideration of the present inventors, when themagnetic member 17 is fixed to the lower end face of thedrive magnet 15, a magnetic flux is concentrated on themagnetic member 17. Further, according to consideration of the present inventors, when the shape of thedrive magnet 15 and the shape of themagnetic member 17 viewed in the up-and-down direction are different from each other, directions of the magnetic lines of force which are generated from thedrive magnet 15 are hard to be directed from the under face and thefirst end face 17 a of themagnetic member 17 to the inner peripheral face of thetube part 10 b. However, when the shape of thedrive magnet 15 and the shape of themagnetic member 17 viewed in the up-and-down direction are substantially the same as each other, directions of the magnetic lines of force which are generated from thedrive magnet 15 are easily directed from the under face and thefirst end face 17 a of themagnetic member 17 to the inner peripheral face of thetube part 10 b. Therefore, in this embodiment, the density of the magnetic flux which is directed to the inner peripheral face of thetube part 10 b from the under face and thefirst end face 17 a of themagnetic member 17 is enhanced effectively. As a result, in this embodiment, even when thedrive magnet 15 and thedrive coil 16 are further made thinner, a driving force of thedrive mechanism 4 can be secured. - In this embodiment, the four corners and their vicinity portions of the
drive coil 16 are disposed in the magnetic field “F” which is directed from the under face and thefirst end face 17 a of themagnetic member 17 to the inner peripheral face of thetube part 10 b. Therefore, even when the movable body 2 is moved to the upper direction from the reference position where the lower end face of thesleeve 8 is abutted with the reference face which is formed on the upper face of thebase member 11, a driving force of thedrive mechanism 4 is hard to be lowered. Accordingly, in this embodiment, the movable body 2 can be moved relatively larger from the reference position to the upper direction by a driving force of thedrive mechanism 4. As a result, in this embodiment, a stroke of the lens is easily secured and a stable driving force of thedrive mechanism 4 can be obtained over a stroke of the lens. - In this embodiment, the
drive magnets 15 are disposed at four corners of thelens drive device 1 whose shape viewed in the optical axis direction is a substantially square shape. Therefore, thedrive magnets 15 can be disposed at four corners of thelens drive device 1 which may be dead spaces in thelens drive device 1 that drives the lens whose shape viewed in the optical axis direction is a substantially circular shape. Further, in this embodiment, thedrive magnet 15 is formed in a substantially triangular prism shape. Therefore, even when spaces of the four corners of thelens drive device 1 are set to be reduced, thedrive magnets 15 can be disposed. Accordingly, in this embodiment, the size of thelens drive device 1 can be reduced. -
FIG. 6 is an explanatory view showing a structure of adrive coil 26 in accordance with another embodiment of the present invention. - In the embodiment described above, the
drive mechanism 4 is provided with onedrive coil 16 which is disposed along the inner peripheral face of thetube part 10 b of thecover member 10. However, thedrive mechanism 4 may be provided, instead of thedrive coil 16, with fourdrive coils 26 as shown inFIG. 6 , each of which is wound around in a substantially triangular tube-like shape and its inner peripheral face is disposed so as to face the side face of thedrive magnet 15 through a predetermined gap space. In the first modified embodiment, thedrive coil 26 is wound around so that its shape viewed in the up-and-down direction is a substantially rectangular equilateral triangle shape. Further, fourdrive coils 26 are fixed to thesleeve 8 so that the inner peripheral face of thedrive coil 26 and the side face of thedrive magnet 15 are substantially parallel to each other with a predetermined gap space therebetween. - Even in the first modified embodiment, effects similar to the above-mentioned embodiment can be obtained. Further, in the first modified embodiment, magnetic flux on the
second end face 17 b side is utilized for driving of the movable body 2 and thus a driving force of thedrive mechanism 4 is further enhanced. In the embodiment described above, only onedrive coil 16 is utilized and thus, in comparison with the first modified embodiment, the structure of thelens drive device 1 is simplified. Further, in comparison with the first modified embodiment, in the embodiment described above, end parts of a conducting wire of only onedrive coil 16 are required to be handled and thus handling of end parts of a conducting wire structuring thedrive coil 16 is simplified. Therefore, manufacturing steps for thelens drive device 1 can be simplified. -
FIGS. 7(A) and 7(B) are explanatory views showing a schematic structure of alens drive device 1 in accordance with another embodiment of the present invention.FIG. 7(A) is an explanatory view showing a schematic structure of thelens drive device 1 which is viewed from an opposite-to-object side andFIG. 7(B) is a cross-sectional view showing the “H-H” cross section inFIG. 7(A) where an object to be photographed or imaged side is located on an upper side.FIG. 8 is an explanatory view showing a schematic structure of alens drive device 1 in accordance with another embodiment of the present invention which is viewed from an opposite-to-object side. - In the embodiment described above, the
lens drive device 1 is formed so that its shape viewed in the optical axis direction is a substantially square shape. Further, thedrive magnet 15 formed in a substantially triangular prism shape is disposed at four corners of thelens drive device 1. However, the present invention is not limited to this embodiment. For example, thelens drive device 1 may be formed so that its shape viewed in the optical axis direction is a substantially rectangular shape. Further, in this case, as shown inFIG. 7(A) , a drive magnet 35 may be formed in a substantially rectangular prism shape and disposed on both sides of the lens drive device in a direction substantially parallel to a long side of thelens drive device 1 when viewed in the optical axis direction. Thelens drive device 1 in accordance with the second modified embodiment is provided with asleeve 38 corresponding to thesleeve 8 of the embodiment described above and a cover member 30 corresponding to thecover member 10. - The drive magnet 35 is formed in a substantially rectangular shape whose shape viewed in the up-and-down direction is elongated in a short side direction of the
lens drive device 1. The drive magnet 35 is disposed so that its three side faces 35 a and an inner peripheral face of thetube part 30 b of the cover member 30 are substantially parallel and faced to each other with a predetermined space therebetween. Further, the drive magnet 35 is fixed to an under face of thebottom part 30 a of the cover member 30 in an abutted state. A lower end face of the drive magnet 35 is fixed to amagnetic member 37 which is formed of magnetic material. Themagnetic member 37 is formed in a flat plate-like shape whose shape viewed in the up-and-down direction is a substantially rectangular shape that is similar to the drive magnet 35. In the second modified embodiment, thebottom part 30 a is an end face side magnetic member to which one end face of the drive magnet 35 is fixed and thetube part 30 b is an outer peripheral side magnetic member which structures an outer peripheral face of the fixedbody 3. Further, themagnetic member 37 is a second end face side magnetic member which is fixed to the other end face of the drive magnet 35. - The drive magnet 35 is magnetized in two poles in the up-and-down direction so that a magnetic pole of the upper end face and a magnetic pole of the lower end face are different from each other. Therefore, as shown in
FIG. 7(B) , in thelens drive device 1 in accordance with the second modified embodiment, a magnetic field “F” is formed which passes thetube part 30 b and thebottom part 30 a of the cover member 30, the drive magnet 35 and themagnetic member 37 to be returned to the inner peripheral face of thetube part 30 b from the under face and the end face of themagnetic member 37. In other words, in thelens drive device 1 in accordance with the second modified embodiment, a magnetic field “F” is formed which passes thetube part 30 b and thebottom part 30 a of the cover member 30 and the drive magnet 35 to be returned from the lower end face of the drive magnet 35 to the inner peripheral face of thetube part 30 b through themagnetic member 37. The magnetic field “F” is, as shown inFIG. 7(A) , directed from the under face and the end face of themagnetic member 37 to the inner peripheral face of thetube part 30 b which is disposed so as to be substantially parallel and faced to the three side faces 35 a of the drive magnet 35. Similarly to the above-mentioned embodiment, the magnetic field “F” is also returned to the inner peripheral face of thetube part 30 b from the vicinity of abutting part of the lower end face of the drive magnet 35 with the upper face of themagnetic member 37. - A drive coil 36 is wound around so that its shape viewed in the up-and-down direction is a substantially rectangular shape which is elongated in a long side direction of the
lens drive device 1. The drive coil 36 is provided withshort side parts 36 a andlong side parts 36 b which are longer than theshort side part 36 a. The drive coil 36 is fixed to an outer peripheral face of thesleeve 38 so as to be along the inner peripheral face of thetube part 30 b. Both end sides of thelong side parts 36 b and theshort side part 36 a of the drive coil 36 are disposed within a space between three side faces 35 a of the drive magnet 35 and the inner peripheral face of thetube part 30 b. Further, the both end sides of thelong side parts 36 b and theshort side part 36 a are disposed within the magnetic field “F” which is directed from the under face and the end faces of themagnetic member 37 to the inner peripheral face of thetube part 30 b. - Also in the
lens drive device 1 in accordance with the second modified embodiment, effects similar to the above-mentioned embodiment can be obtained. Further, in thelens drive device 1 in accordance with the second modified embodiment, the drive magnets 35 are disposed on both sides of thelens drive device 1 in a direction substantially parallel to the long side of thelens drive device 1 when viewed in the optical axis direction. Therefore, the size of thelens drive device 1 can be further reduced in a direction substantially parallel to the short side of thelens drive device 1 when viewed in the optical axis direction. In accordance with an embodiment of the present invention, instead of the drive coil 36, as shown inFIG. 8 , it may be structured that two drive coils 46 which are wound around in a substantially rectangular tube shape and whose inner peripheral side is disposed so as to face the side face of the drive magnet 35 through a predetermined space are fixed to an outer peripheral face of thesleeve 38. -
FIGS. 9(A) and 9(B) are explanatory views showing a schematic structure of alens drive device 1 in accordance with another embodiment of the present invention.FIG. 9(A) is an explanatory view showing a schematic structure of thelens drive device 1 which is viewed from an opposite-to-object side andFIG. 9(B) is a cross-sectional view showing the “J-J” cross section inFIG. 9(A) where an object to be photographed or imaged side is located on an upper side. - In the embodiment described above, the
drive magnet 15 which is formed in a substantially triangular prism shape is disposed at four corners of thelens drive device 1. However, the present invention is not limited to this embodiment. For example, as shown inFIG. 9(A) , a drive magnet 55 which is formed in a substantially rectangular plate shape may be disposed on each of four side faces of thelens drive device 1. - In the third modified embodiment, the drive magnet 55 is disposed so that its one side face 55 a and an inner peripheral face of a
tube part 10 b of acover member 10 are in substantially parallel and faced to each other with a predetermined space therebetween. Further, the drive magnet 55 is fixed to an under face of abottom part 10 a of thecover member 10 in an abutted state. A lower end face of the drive magnet 55 is fixed to amagnetic member 57 which is formed of magnetic material. Themagnetic member 57 is formed in a flat plate-like shape which is, similarly to the drive magnet 55, substantially rectangular shape when viewed in the up-and-down direction. In the third modified embodiment, themagnetic member 57 is a second end face side magnetic member which is fixed to the other end face of the drive magnet 55. - The drive magnet 55 is magnetized in two poles in the up-and-down direction so that a magnetic pole of the upper end face and a magnetic pole of the lower end face are different from each other. Therefore, similarly to the above-mentioned embodiment, in the
lens drive device 1 in accordance with the third modified embodiment, a magnetic field “F” is formed which passes thetube part 10 b and thebottom part 10 a, the drive magnet 55 and themagnetic member 57 to be returned to the inner peripheral face of thetube part 10 b from the under face and the end face of themagnetic member 57. The magnetic field “F” is, as shown inFIG. 9(A) , directed from the under face and the end face of themagnetic member 57 to the inner peripheral face of thetube part 10 b which is disposed so as to be substantially parallel and faced to the side face 55 a of the drive magnet 55. Similarly to the above-mentioned embodiment, the magnetic field “F” is also returned to the inner peripheral face of thetube part 10 b from the vicinity of abutting part of the lower end face of the drive magnet 55 with the upper face of themagnetic member 57. - A part of the
drive coil 16 is disposed within a space between the side face 55 a of the drive magnet 55 and the inner peripheral face of thetube part 10 b. Further, the part of thedrive coil 16 is disposed in the magnetic field “F” which is directed from the under face and the end face of themagnetic member 57 to the inner peripheral face of thetube part 10 b. Also in the third modified embodiment, effects similar to the above-mentioned embodiment can be obtained. -
FIG. 10 is an enlarged sectional view showing a part of alens drive device 1 in accordance with another embodiment of the present invention. - In the embodiment described above, the upper end face of the
drive magnet 15 is fixed to the under face of thebottom part 10 a in an abutted state with the under face of thebottom part 10 a. However, the present invention is not limited to this embodiment. For example, as shown inFIG. 10 , amagnetic member 67 may be formed so that anend face 67 a of themagnetic member 67 which is fixed to a lower end face of thedrive magnet 15 is abutted with an inner peripheral face of atube part 72 of acover member 70. In this case, the end face 67 a is fixed to the inner peripheral face of thetube part 72 and a space is formed between an upper end face of thedrive magnet 15 and abottom part 71 of thecover member 70. - In the fourth modified embodiment, a magnetic field “F” which is directed from the inner peripheral face of the
tube part 72 to an upper end face of thedrive magnet 15 is formed and thus four corners and their vicinity portions of thedrive coil 16 are disposed in the magnetic field “F” which is directed from the inner peripheral face of thetube part 72 to the upper end face of thedrive magnet 15. Further, in the fourth modified embodiment, thecover member 70 may be preferably structured of abottom part 71 made of nonmagnetic material and atube part 72 made of magnetic material so that magnetic lines of force generated from thedrive magnet 15 are not directed from thebottom part 71 to the upper end face of thedrive magnet 15. In this embodiment, thelens drive device 1 may be provided with fourmagnetic members 67 to which respective fourdrive magnets 15 are fixed, or onemagnetic member 67 to which all of fourdrive magnets 15 are fixed. Also in the fourth modified embodiment, effects similar to the above-mentioned embodiment can be obtained. - In the fourth modified embodiment, the
magnetic member 67 is an end face side magnetic member to which one end face of thedrive magnet 15 is fixed, and thetube part 72 is an outer peripheral side magnetic member which structures the outer peripheral face of the fixedbody 3. Further, in the fourth modified embodiment, a magnetic member is not fixed to the upper end face of thedrive magnet 15 but a magnetic member may be fixed to the upper end face of thedrive magnet 15. In this case, the magnetic member is a second end face side magnetic member. - In the embodiment described above, the
magnetic member 17 is fixed to the lower end face of thedrive magnet 15 but nomagnetic member 17 is fixed to the lower end face of thedrive magnet 15. In this case, a length of thedrive magnet 15 is capable of being increased in the up-and-down direction by a thickness of themagnetic member 17 and thus a driving force of thedrive mechanism 4 can be enhanced. Further, in this case, themagnetic member 17 is not required to be fixed to a lower end face of thedrive magnet 15 and thus assembling steps for thelens drive device 1 can be simplified. - In the embodiment described above, the
cover member 10 is structured of thebottom part 10 a and thetube part 10 b, and thebottom part 10 a and thetube part 10 b are formed in an integral manner. However, the present invention is not limited to this embodiment. For example, the bottom part made of magnetic material and the tube part made of magnetic material may be formed of separate members. In this case, the end face of the bottom part and the inner peripheral face of the tube part may be abutted with each other, or a gap space may be formed between the end face of the bottom part and the inner peripheral face of the tube part. Further, the under face of the bottom part and the upper end face of the tube part may be abutted with each other, or a gap space may be formed between the under face of the bottom part and the upper end face of the tube part. However, in order to restrain leakage of magnetic flux from a portion between the bottom part and the tube part to enhance magnetic flux density passing through thedrive coil 16, it is preferable that the end face of the bottom part and the inner peripheral face of the tube part are abutted with each other, or the under face of the bottom part and the upper end face of the tube part are abutted with each other. - In the embodiment described above, the
drive magnet 15 is formed in a substantially triangular prism shape, but thedrive magnet 15 may be formed in a polygonal prism shape other than a substantially triangular prism shape or may be formed in a substantially circular cylinder shape or a substantially elliptical cylinder shape. Further, in the embodiment described above, thelens drive device 1 is formed in a roughly quadrangular shape when viewed in the optical axis direction. However, thelens drive device 1 may be formed in a roughly polygonal shape other than a roughly rectangular shape when viewed in the optical axis direction or may be formed in a roughly circular shape or elliptical shape when viewed in the optical axis direction. In these cases, thedrive coil 16 may be wound around, for example, in a cylindrical tube shape or the like depending on the shape of thelens drive device 1 and the shape of thedrive magnet 15 when viewed in the optical axis direction. Further, thedrive coil 26 in the first modified embodiment may be also wound around, for example, in a cylindrical tube shape or the like depending on the shape of thelens drive device 1 and the shape of thedrive magnet 15 when viewed in the optical axis direction. - In the embodiment described above, the shape of the
drive magnet 15 when viewed in the up-and-down direction is substantially the same as the shape of themagnetic member 17. However, the shape of thedrive magnet 15 when viewed in the up-and-down direction may be different from the shape of themagnetic member 17. Further, in the embodiment described above, thedrive magnet 15 is disposed at four corners of thelens drive device 1. However, when a sufficient driving force for the movable body 2 is obtained, thedrive magnet 15 may be disposed at three corners, two corners or only one corner of the four corners of thelens drive device 1. - While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention.
- The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Claims (21)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2010070526A JP5591571B2 (en) | 2010-03-25 | 2010-03-25 | Lens drive device |
JP2010-070526 | 2010-03-25 |
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JP (1) | JP5591571B2 (en) |
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USD902980S1 (en) * | 2018-01-12 | 2020-11-24 | Tdk Taiwan Corp. | Driving unit for a camera lens |
US20220254554A1 (en) * | 2021-02-09 | 2022-08-11 | At&S Austria Technologie & Systemtechnik Aktiengesellschaft | Component Carrier With Cavity Accommodating at Least Part of Driven Body Being Magnetically Drivable to Move |
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JP2010169901A (en) * | 2009-01-23 | 2010-08-05 | Nidec Sankyo Corp | Lens driving device |
JP5919072B2 (en) * | 2012-04-10 | 2016-05-18 | 日本電産サンキョー株式会社 | Manufacturing method of lens driving device |
CN103001375A (en) * | 2012-09-29 | 2013-03-27 | 苏州贝腾特电子科技有限公司 | Shell for miniature driving motor |
WO2014137102A1 (en) * | 2013-03-07 | 2014-09-12 | 자화전자(주) | Camera lens module for mobile terminal |
CN106324941B (en) * | 2015-07-02 | 2019-08-27 | 日本电产三协株式会社 | Band image shake correction function optical unit |
KR102559545B1 (en) * | 2015-08-06 | 2023-07-25 | 엘지이노텍 주식회사 | A lens moving unit |
JP6852432B2 (en) * | 2017-02-09 | 2021-03-31 | Tdk株式会社 | Lens drive device and electromagnetic drive unit |
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US7916412B2 (en) * | 2008-02-29 | 2011-03-29 | Johnson Electric S.A. | Lens driving device |
US20100060999A1 (en) * | 2008-09-08 | 2010-03-11 | Nidec Sankyo Corporation | Magnetic device and lens drive device |
US20100149668A1 (en) * | 2008-12-12 | 2010-06-17 | Nidec Sankyo Corporation | Lens drive device |
Cited By (2)
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USD902980S1 (en) * | 2018-01-12 | 2020-11-24 | Tdk Taiwan Corp. | Driving unit for a camera lens |
US20220254554A1 (en) * | 2021-02-09 | 2022-08-11 | At&S Austria Technologie & Systemtechnik Aktiengesellschaft | Component Carrier With Cavity Accommodating at Least Part of Driven Body Being Magnetically Drivable to Move |
Also Published As
Publication number | Publication date |
---|---|
JP5591571B2 (en) | 2014-09-17 |
JP2011203475A (en) | 2011-10-13 |
US8040624B1 (en) | 2011-10-18 |
CN102200621A (en) | 2011-09-28 |
KR20110107742A (en) | 2011-10-04 |
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