JP2005352032A - Lens driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens driving device provided with configuration facilitating assembling working while providing a function properly guiding a lens in the direction of an optical axis. <P>SOLUTION: The lens driving device 1 comprises a lens moving body 2 holding moving lenses 13 and 14, a drive means 4 for moving the lens moving body 2 in the direction of the optical axis L, and a fixing body 3 for movably supporting the lens moving body 2 in the direction of the optical axis L. The drive means 4 is composed of a drive coil 5 arranged on the lens moving body 2, and a drive magnet 6 and a plate-like yoke 8 arranged on the fixing body 3. The yoke 8 comprises an inner yoke (guide projection part) 8a for guiding the lens moving body 2 in the direction of the optical axis L. The lens moving body 2 comprises a sliding hole 2b inserting the inner yoke 8a. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lens driving device used for a relatively small camera such as a camera of a camera-equipped mobile phone.

  As a lens driving device for driving a lens such as a photographing lens of a camera in the optical axis direction, a lens moving body for holding the lens, a driving means for moving the lens moving body in the optical axis direction of the lens, and a lens moving body A lens driving device is used that includes a fixed body that is movably supported in the optical axis direction, and directly magnetically drives the lens.

  As this type of lens driving device, a lens using a so-called voice coil motor comprising a driving coil disposed on a lens moving body and a driving magnet and a yoke disposed on a fixed body as driving means for the lens moving body. A drive device is known (see, for example, Patent Documents 1 and 2).

  In the lens driving devices described in Patent Documents 1 and 2, a lens is held on the inner peripheral side of a lens moving body formed in a rectangular tube shape, and a driving coil is wound around the outer peripheral side. Further, a yoke including an inner yoke and an outer yoke is fixed to the fixed body, and a drive magnet is fixed inside the outer yoke. The lens moving body is supported by the fixed body so as to be movable in the optical axis direction so that the driving coil wound around the lens moving body is disposed between the inner yoke and the driving magnet. A voice coil motor is configured as a body driving means.

Further, in the lens driving devices described in Patent Documents 1 and 2, in order to guide the lens moving body holding the lens in the optical axis direction, the fixed body has two guide shafts extending in the optical axis direction. The lens moving body is formed with a sliding hole through which the guide shaft is inserted and in sliding contact with the guide shaft.
JP-A-8-94904 Japanese Patent Laid-Open No. 5-264878

  However, since the lens driving device disclosed in the above-mentioned patent document employs a configuration in which the guide shaft is in a standing contact with the fixed body, in order to guide the lens moving body appropriately in the optical axis direction, the guide shaft is used. There is a problem that assembly work is difficult because it is necessary to erect with high accuracy with respect to the fixed body. In particular, since two guide shafts are used, if the parallelism between the guide shafts is not ensured, the lens moving body cannot be properly guided in the optical axis direction, and the assembly work becomes more difficult. There's a problem.

  If a voice coil motor is used as the driving means, the driving coil must always be energized when the lens is stopped and held in a fixed posture at the lens holding position where photographing is performed. Therefore, there is a problem that power consumption increases. In particular, when a lens driving device is to be mounted on a camera-equipped mobile phone or the like, the problem of power consumption becomes significant.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a lens driving device that has a function of appropriately guiding a lens in the optical axis direction and has a configuration that facilitates assembly work. Another object of the present invention is to provide a lens driving device having a simple configuration and a configuration capable of reducing power consumption when holding the position of the lens.

  In order to solve the above-described problems, in the present invention, a lens moving body that holds a lens, a driving unit that moves the lens moving body in the optical axis direction of the lens, and a lens moving body that moves in the optical axis direction In the lens driving device including a fixed body that can be supported, the driving means includes a driving coil disposed in one of the lens moving body and the stationary body, and a driving magnet disposed in the other. And a plate-like yoke disposed on the fixed body to form a magnetic circuit together with the drive coil and the drive magnet, and the yoke is arranged in the optical axis direction to guide the lens moving body in the optical axis direction. The lens moving body includes a sliding hole through which the guide protrusion is inserted and in sliding contact with the guide protrusion.

  In the present invention, the plate-like yoke disposed on the fixed body includes a guide protrusion that extends in the optical axis direction in order to guide the lens moving body in the optical axis direction. Since the yoke is plate-shaped, the reference for fixing the yoke to the fixed body can be formed as a fixed reference surface. Therefore, by fixing the yoke to the yoke fixing portion formed on the fixed body with reference to the fixed reference surface, the reference of the yoke to the fixed body can be easily performed. In addition, by forming the guide protrusion with high accuracy with respect to the fixed reference surface, the guide protrusion can be erected with high accuracy with respect to the fixed body. Therefore, the lens can be appropriately guided in the optical axis direction by inserting the guide protrusion through the slide hole provided in the lens moving body and bringing the slide hole and the guide protrusion into sliding contact. Furthermore, for example, even when a plurality of guide protrusions are provided, it is easy to ensure the parallelism between the guide protrusions.

  In addition, since a part of the yoke is used as the guide protrusion, it is not necessary to separately provide a guide shaft for guiding the lens moving body in the optical axis direction. Therefore, the configuration of the lens driving device is simplified, and the device can be miniaturized.

  In the present invention, it is preferable that the guide protrusion and the sliding hole are provided at a plurality of locations around the optical axis of the lens. In this case, when the lens moving body is guided in the optical axis direction, the lens moving body is less likely to be inclined, and the lens moving body can be reliably guided. In order to reliably guide the lens moving body in the optical axis direction, it is preferable that the guide protrusions and the sliding holes are provided at three or more locations. In order to guide the lens moving body more reliably, it is preferable that the guide protrusion and the sliding hole are provided at equiangular intervals around the optical axis.

  In the present invention, the yoke includes an inner yoke serving as the guide protrusion, an outer yoke formed outside the inner yoke in a direction perpendicular to the optical axis, and a connection that connects the inner yoke and the outer yoke. It is preferable that the connecting portion is fixed to a yoke fixing portion formed on the fixing body. In this case, a fixed reference surface can be formed on the connecting portion, and an inner yoke serving as a guide protrusion can be easily and accurately formed with respect to the fixed reference surface. For example, the inner yoke can be easily and accurately formed with respect to the fixed reference surface by bending using a press. Therefore, the guide protrusion can be erected with high accuracy with respect to the fixed body simply by fixing the connecting portion to the yoke fixing portion. Even if a plurality of guide protrusions are provided, it is easy to ensure the parallelism between the guide protrusions.

  In the present invention, the yoke fixing portion is formed with a fitting convex portion for fixing the yoke, and the yoke is formed with a fitting hole for fitting with the fitting convex portion. preferable. In this case, the positioning of the yoke with respect to the fixed body is facilitated, and the assembly work of the lens driving device is simplified.

  In the present invention, it is preferable that the lens moving body is formed in a cylindrical shape, the lens moving body holds the lens on the inner peripheral side, and the driving coil is wound on the outer peripheral side. In this case, the lens moving body can also be used as a coil bobbin. Further, when the lens moving body is also used as a coil bobbin, the winding operation of the drive coil becomes easy. That is, since the drive coil can be wound directly on the outer peripheral side of the lens moving body, for example, an operation step of manufacturing an air-core drive coil and attaching it to the lens moving body can be omitted. Coil winding work becomes easy.

  In the present invention, it is preferable that a lubricating coating is formed on at least one surface of the guide protrusion and the sliding hole. In this case, the sliding resistance between the guide protrusion and the sliding hole is reduced, and the power consumption during movement of the lens moving body can be reduced. Further, the movement of the lens moving body in the optical axis direction is performed smoothly.

  In the present invention, the lens moving body or the fixed body provided with the drive coil includes a magnetic piece, and the movable range end position of the lens moving body is obtained by a magnetic attractive force between the magnetic piece and the drive magnet. It is preferable to hold the lens moving body. In this case, by setting the movable range end position of the lens moving body as a position where photographing is performed, that is, a lens holding position, the driving coil does not need to be energized at the holding position, and the lens holding position is maintained. Power consumption in the state can be reduced.

  In the present invention, the lens moving body or the fixed body provided with the magnetic piece is formed with a magnetic piece holding portion that extends in a direction perpendicular to the optical axis to hold the magnetic piece. The holding position is preferably configured to be adjustable in a direction perpendicular to the optical axis. In this case, the magnetic attraction force generated between the drive magnet and the magnetic piece can be adjusted by adjusting the holding position of the magnetic piece. Accordingly, an appropriate magnetic attractive force can be set between the drive magnet and the magnetic piece.

  As described above, in the present invention, the plate-like yoke includes the guide protrusion that extends in the optical axis direction in order to guide the lens moving body in the optical axis direction. Therefore, the reference for fixing the yoke to the fixed body is formed as a fixed reference surface, and the yoke is fixed to the yoke fixing portion formed on the fixed body, so that the reference of the yoke to the fixed body can be easily made. be able to. In addition, by forming the guide protrusion with high accuracy with respect to the fixed reference surface, the guide protrusion can be erected with high accuracy with respect to the fixed body. Therefore, assembly work is facilitated. In addition, the lens can be appropriately guided in the optical axis direction by bringing the sliding hole provided in the lens moving body into sliding contact with the guide protrusion.

  In addition, the lens moving body or the fixed body provided with the drive coil includes a magnetic piece, and the lens moving body is held at the end of the movable range of the lens moving body by the magnetic attractive force between the magnetic piece and the driving magnet. By doing so, there is no need to energize the drive coil at the lens holding position. Therefore, with a simple configuration, it is possible to reduce power consumption when holding the position of the lens.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

(Configuration of lens driving device)
FIG. 1 is a side sectional view showing a lens driving device according to an embodiment of the present invention. 2A and 2B show a fixed-side member of the lens driving device shown in FIG. 1, FIG. 2A is a top view thereof, and FIG. 2B is a cross-sectional view taken along the line AA of FIG. 3A and 3B show a fixed body of the lens driving device shown in FIG. 1, FIG. 3A is a top view thereof, and FIG. 3B is a cross-sectional view taken along the line BB of FIG. 4A and 4B show a yoke of the lens driving device shown in FIG. 1, FIG. 4A is a top view thereof, and FIG. 4B is a cross-sectional view taken along a line CC in FIG. 5 shows a moving side member of the lens driving device shown in FIG. 1, wherein (A) is a top view thereof, (B) is a sectional view taken along the line DD of (A), and (C) is a bottom view thereof. is there.

  A lens driving device 1 according to the present embodiment is applied to a thin camera mounted on a portable device such as a mobile phone, and includes a lens moving body 2 that holds moving lenses 13 and 14, and the lens moving body 2. Driving means 4 for moving the lens moving body 13 and 14 in the optical axis L direction, and a fixed body 3 that supports the lens moving body 2 so as to be movable in the optical axis L direction. In this embodiment, the drive means 4 is composed of a drive coil 5, a drive magnet 6, and a yoke 8 that forms a magnetic circuit together with the drive coil 5 and the drive magnet 6. A cover 10 holding a fixed lens 12 is fixed to the upper end of the fixed body 3 in the figure.

  As shown in FIGS. 1 and 2, the fixed body 3 is provided with a drive magnet 6 and a yoke 8.

  The fixed body 3 in the present embodiment is a resin member formed in a bottomed cylindrical shape having a bottom portion and a cylindrical portion, and forms a main body case of the lens driving device 1 (see FIG. 3). At the bottom of the fixed body 3, an opening 3a for capturing an image of the object to be photographed is formed. Around the opening 3a, a yoke fixing portion 3b for fixing the yoke 8 is formed. Specifically, the yoke fixing portions 3b are formed at three locations with a 120 ° pitch centered on the optical axis L. Between the respective yoke fixing portions 3b, restriction recesses 3c for restricting the movable range of the lens moving body 2 in the optical axis L direction in the illustrated downward direction are formed at three positions with a 120 ° pitch centered on the optical axis L. Has been. As shown in FIG. 3A, the boundary line between the yoke fixing portion 3b and the regulating recess 3c is formed at a pitch of 60 ° with the optical axis L as the center.

  The yoke fixing portion 3b includes a fixing surface 3b1 and a fitting convex portion 3b2 formed to fix the yoke 8 at a substantially central position of the fixing surface 3b1. Since the fixing surface 3b1 fixes the yoke 8 with high accuracy, the flatness is ensured with high accuracy. Moreover, the regulation recessed part 3c is formed in the state depressed from the fixed surface 3b1. Of the restricting portions 3c formed at three places, a lead hole 3d for drawing a wiring board 11 described later to the outside of the fixed body 3 is formed at one place so as to penetrate from the restricting recess 3c to the outside of the fixed body 3. Has been.

  In addition, a protrusion 3e used for positioning the yoke 8 in the circumferential direction is formed on the outer peripheral side of each regulating recess 3c so as to protrude in the optical axis L direction. Specifically, the cross section in the direction of the optical axis L is formed in a substantially arc shape along the inner peripheral surface of the cylindrical portion of the fixed body 3.

  The yoke 8 is formed of a plate-like magnetic member, and includes an inner yoke 8a, an outer yoke 8b formed radially outside the inner yoke 8a, and a connecting portion that connects the inner yoke 8a and the outer yoke 8b. 8c. Specifically, the yoke 8 has a groove shape in which the connecting portion 8c connects the inner yoke 8a and the outer yoke 8b at the lower end in the figure, and the inner yoke 8a and the outer yoke 8b stand upright from the connecting portion 8c. (See FIG. 4). The illustrated lower surface of the connecting portion 8 c is a fixed reference surface 8 e for fixing the yoke 8 to the fixed body 3. In this embodiment, the yoke 8 is formed by bending a thin plate-like magnetic member with a press, and the perpendicularity of the inner yoke 8a and the outer yoke 8b with respect to the fixed reference surface 8e is ensured with high accuracy.

  As shown in FIG. 4A, the inner yoke 8a is formed in a substantially arc shape centered on the optical axis L when viewed from above. Similarly, the outer yoke 8b is formed in a substantially arc shape centered on the optical axis L when viewed from above, and the outer yoke 8b is disposed on the fixed body 3 and is a cylinder of the fixed body. It is arranged along the part. Further, a fitting hole 8d that fits with the fitting convex portion 3b2 formed in the fixed body 3 is formed at a substantially central position of the connecting portion 8c.

  In this embodiment, three yokes 8 are fixed to a yoke fixing portion 3 b formed on the fixed body 3. More specifically, the yoke 8 is fixed to the yoke fixing portion 3b in a state where the fixing reference surface 8e is in contact with the fixing surface 3b1 and the fitting hole 8d is fitted to the fitting convex portion 3b2. ing. At this time, the circumferential end of the outer yoke 8b is adjacent to the protrusion 3e. In a state where the yoke 8 is fixed to the fixed body 3, the inner yoke 8a and the outer yoke 8b extend in the optical axis L direction. In this embodiment, the inner yoke 8a is a guide protrusion for guiding the lens moving body 2 in the direction of the optical axis L, and the inner yoke 8a has a pitch of approximately 120 ° with the optical axis L as the center. It is erected on the fixed body 3 at equal intervals. On the surface of the inner yoke 8a, the maximum height of the surface roughness is about 0.1 μm or less in order to reduce sliding resistance with a sliding hole 2b of the lens moving body 2 described later. In order to reduce the sliding resistance with the sliding hole 2b, a lubricating coating may be formed on the surface of the inner yoke 8a. Specifically, an electroless nickel plating film in which polytetrafluoroethylene (PTFE) is dispersed may be formed on the surface of the inner yoke 8a.

  As shown in FIG. 2A, the drive magnet 6 is a thin plate-like permanent magnet whose cross section in the optical axis L direction is formed in a substantially arc shape and extends in the optical axis L direction. Each side is magnetized to a single pole. For example, the inner peripheral side of the drive magnet 6 is magnetized to the N pole, and the outer peripheral side is magnetized to the S pole. In this embodiment, three drive magnets 6 are disposed on the fixed body 3. Specifically, the drive magnet 6 is fixed to the inner peripheral side of the outer yoke 8b of the three yokes 8 fixed to the fixed body 3 by a fixing means such as adhesion.

  As shown in FIG. 5, the lens moving body 2 is a resin member formed in a cylindrical shape having flanges 2 a and 2 a at the upper and lower ends in the drawing. In this embodiment, the lens moving body 2 holds the moving lenses 13 and 14 on the inner peripheral side, and the drive coil 5 is directly wound between the flanges 2a and 2a on the outer peripheral side. That is, in this embodiment, the lens moving body 2 also serves as a coil bobbin. In this embodiment, the lens moving body 2 directly holds the moving lenses 13 and 14 on the inner peripheral side thereof. However, the moving lens 13 and 14 may be held via the lens barrel. .

  The lens moving body 2 has a sliding hole 2b through which an inner yoke 8a serving as a guide protrusion is inserted and slidably contacted with the inner yoke 8a. And formed in three places. As shown in FIG. 5A, the sliding hole 2b is formed in a substantially arc shape when viewed from above, and is formed so as to penetrate the lens moving body 2 in the optical axis L direction. In addition, the radial width of the sliding hole 2b is larger than the radial thickness of the inner yoke 8a. The radial gap with the yoke 8a is set to be 0.1 mm or less on one side. Thus, a sliding guide is formed by the inner yoke 8a and the sliding hole 2b, and the lens moving body 2 is appropriately guided in the optical axis L direction by the inner yoke 8a.

  In order to reduce the sliding resistance with the inner yoke 8a, a lubricating coating may be formed on the surface of the sliding hole 2b. Specifically, an electroless nickel plating film in which polytetrafluoroethylene (PTFE) is dispersed may be formed on the surface of the sliding hole 2b. In this case, it is necessary to form the lens moving body 2 with a heat resistant resin such as a liquid crystal resin or a polyphenylene sulfide resin (PPS).

  A magnetic piece holder 2 c for holding the chip-like magnetic piece 9 is formed on the upper flange 2 a of the lens moving body 2 in the figure. Specifically, it is formed at three locations approximately at the center in the circumferential direction of the sliding hole 2b and outward from the radial direction of the sliding hole 2b. The holding position of the magnetic piece 9 can be adjusted in the radial direction.

  On the bottom surface of the lens moving body 2, there are regulating convex portions 2 d that abut the regulating concave portion 3 c of the fixed body 3 and regulate the movable range of the lens moving body 2 in the downward direction between the three sliding holes 2 b. Is formed. A wiring board 11 for supplying a drive current to the drive coil 5 is fixed to the bottom surface of the lens moving body 2. The wiring board 11 in this embodiment is a flexible printed circuit board (FPC), and the end of the drive coil 5 is connected to the wiring pattern on the wiring board 11.

  The lens moving body 2 in which the driving coil 5 is wound on the outer peripheral side and the magnetic piece 9 is held by the magnetic piece holding portion 2 c is disposed inside the cylindrical portion of the fixed body 3. Specifically, the inner yoke 8a is inserted into the sliding hole 2b, and the restricting convex portion 2d and the restricting concave portion 3c are arranged to face each other in the optical axis L direction. At this time, the drive coil 5 is disposed so as to be sandwiched in the radial direction by the drive magnet 6 and the inner yoke 8 a, and the drive coil 5, the drive magnet 6 and the yoke 8 serve as the drive means 4. A voice coil motor is configured.

  When the lens moving body 2 is disposed inside the cylindrical portion of the fixed body 3, each magnetic piece 9 faces the upper end surface of the drive magnet 6 in the direction of the optical axis L in the figure. . Further, when the lens driving device 1 is viewed from above, each magnetic piece 9 is arranged at the center position in the circumferential direction of the driving magnet 6. The wiring board 11 is drawn out of the fixed body 3 through a lead hole 3 d formed in the fixed body 3.

  The cover 10 is a resin member formed in a bottomed cylindrical shape, and is formed so that the outer diameter thereof substantially coincides with the fixed body 3. An opening is formed at the bottom of the cover 10, and the fixed lens 12 is held in this opening. Further, on the lower side of the cover 10 in the figure, a restricting portion (not shown) that restricts the movable range of the lens moving body 2 in the upward direction in the optical axis L direction is formed. The cover 10 is fixed to the fixed body 3 so that the optical axes of the fixed lens 12 and the moving lenses 13 and 14 coincide.

(Operation of lens driving device)
The operation of the lens driving device 1 configured as described above will be described below.

  In this embodiment, as shown in FIG. 1, the normal moving lens holding position is a state in which the restriction convex portion 2 d of the lens moving body 2 is in contact with the restriction concave portion 3 c of the fixed body 3. In this state, the lens moving body 2 is stably held in the direction of the optical axis L by the magnetic attractive force between the magnetic piece 9 and the drive magnet 6. Therefore, the drive coil 5 is in a non-energized state at the normal moving lens holding position. Further, since each magnetic piece 9 is arranged at the center position in the circumferential direction of the drive magnet 6, the lens moving body 2 is stably held also in the circumferential direction.

  When a current is supplied to the drive coil 5 so that the lens moving body 2 moves in the upward direction in the figure while the lens moving body 2 is held at the normal moving lens holding position, the lens moving body 2 8A and the sliding hole 2b are guided in the direction of the optical axis L, and a focusing operation is performed in which the lens moving body 2 moves until the upper end of the lens moving body 2 comes into contact with the restricting portion formed on the cover 10. The lens moving body 2 that has moved from the normal moving lens holding position to a predetermined position in the optical axis L direction by this focusing operation is balanced with the magnetic attraction force between the magnetic piece 9 and the drive magnet 6. Is kept stable at a predetermined position. In addition, since each magnetic piece 9 is arrange | positioned in the center position of the circumferential direction of the drive magnet 6, the lens moving body 2 has the magnetic piece 9 and the drive magnet 6 in the circumferential direction. Is stably held by.

  When a current is supplied to the drive coil 5 so that the lens moving body 2 moves downward in the figure at the predetermined position, the lens moving body 2 is moved in the direction of the optical axis L by the inner yoke 8a and the sliding hole 2b. Move as guided by. For example, the lens 2 is moved until the restriction convex portion 2d of the lens moving body 2 comes into contact with the restriction concave portion 3c of the fixed body 3, and is held at a normal moving lens holding position. Depending on the magnitude of the magnetic attractive force generated between the magnetic piece 9 and the drive magnet 6, the lens moving body 2 can be moved in a normal state by turning off the drive coil 5 at the predetermined position. It is also possible to move to the moving lens holding position.

(Main effects of this form)
As described above, in the lens driving device 1 according to the present embodiment, the plate-like yoke 8 disposed on the fixed body 3 serves as a guide protrusion for guiding the lens moving body 2 in the optical axis L direction. A yoke 8a is provided. Since the yoke 8 is plate-shaped, the fixed reference surface 8e can be formed as a reference for fixing the yoke 8 to the fixed body 3. Therefore, the reference of the yoke 8 with respect to the fixed body 3 can be easily performed by fixing the yoke 8 by bringing the fixed reference surface 8e into contact with the fixed surface 3b1 of the yoke fixing portion 3c formed on the fixed body 3. Can do. Further, since the perpendicularity of the inner yoke 8a with respect to the fixed reference surface 8e is ensured with high accuracy, the inner yoke 8a can be erected with high accuracy with respect to the fixed body 3. That is, the inner yoke 8a can be erected with high accuracy with respect to the fixed body 3 by ensuring the accuracy of the components. Therefore, it is not necessary to adjust the perpendicularity of the inner yoke 8a that is a guide protrusion with respect to the fixed body 3 during assembly, and the assembly operation can be performed easily and stably. Further, the inner yoke 8a is inserted into the sliding hole 2b provided in the lens moving body 2, and the sliding hole 2b and the inner yoke 8a are slidably contacted to appropriately guide the moving lenses 13 and 14 in the optical axis L direction. can do.

  In particular, in this embodiment, the fixed reference surface 8e is formed in the connecting portion 8c that connects the inner yoke 8a and the outer yoke 8b. Therefore, the perpendicularity of the inner yoke 8a with respect to the fixed reference surface 8e can be ensured accurately and easily by bending with a press. Therefore, the inner yoke 8a, which is a guide protrusion, can be set up with high accuracy with respect to the fixed body 3 only by fixing the yoke 8 to the fixed body 3 with the fixed reference surface 8e in contact with the fixed surface 3b1. be able to. In particular, in this embodiment, the inner yokes 8a are erected at three places, but the parallelism between the inner yokes 8a can be easily ensured.

  Further, since the inner yoke 8a is used as a guide protrusion, it is not necessary to separately provide a guide shaft for guiding the lens moving body 2 in the optical axis L direction. Therefore, the configuration of the lens driving device 1 is simplified, the device can be miniaturized, and can be applied to a thin camera mounted on a portable device such as a cellular phone.

  In the present embodiment, the sliding guide formed by the inner yoke 8a and the sliding hole 2b is provided at three locations with the optical axis L as the center. Therefore, when the lens moving body 2 is guided in the optical axis L direction, the lens moving body 2 is less likely to be inclined, and the lens moving body 2 can be reliably guided. In particular, in this embodiment, since the inner yoke 8a and the sliding hole 2b are provided at equiangular intervals with the optical axis L as the center, the inclination of the lens moving body 2 can be further suppressed. It is possible to appropriately guide in the direction of the optical axis L.

  In this embodiment, a fitting convex portion 3 b 2 is formed on the yoke fixing portion 3 b of the fixed body 3, and a fitting hole 8 d is formed on the connecting portion 8 c of the yoke 8. Further, the fixed body 3 is formed with a protrusion 3e used for positioning the yoke 8 in the circumferential direction. Therefore, the positioning of the yoke 8 with respect to the fixed body 3 is facilitated, and the assembly work of the lens driving device 1 can be simplified.

  In this embodiment, the drive coil 5 is wound directly on the outer peripheral side of the lens moving body 2. That is, the lens moving body 2 also serves as a coil bobbin. Therefore, the winding work of the drive coil 5 becomes easy. That is, since the drive coil 5 can be wound directly on the outer peripheral side of the lens moving body 2, for example, an operation step of manufacturing an air-core drive coil and attaching it to the lens moving body 2 can be omitted. This makes it easy to wind the drive coil 5.

  In the present embodiment, the maximum height of the surface roughness is approximately 0.1 μm or less on the surface of the inner yoke 8a. Therefore, the sliding resistance between the sliding hole 2b and the inner yoke 8a can be reduced. Also, the sliding resistance between the sliding hole 2b and the inner yoke 8a can be reduced by forming a lubricating coating on the surface of at least one of the inner yoke 8a and the sliding hole 2b. As a result, power consumption during movement of the lens moving body 2 can be reduced, and the movement of the lens moving body 2 in the direction of the optical axis L is smoothly performed.

  In this embodiment, the lens moving body 2 includes a magnetic piece 9 and is held by a normal moving lens that is the end position of the movable range of the lens moving body 2 in the downward direction by the magnetic attractive force of the magnetic piece 9 and the drive magnet 6. At the position, the lens moving body 2 is stably held in the optical axis L direction. Therefore, it is not necessary to keep the drive coil 5 energized at the normal moving lens holding position, and it is only necessary to energize the drive coil 5 only during the focusing operation. Therefore, the power consumption in the holding state of the movable lenses 13 and 14 can be reduced.

  In this embodiment, the magnetic piece holding portion 2c for holding the magnetic piece 9 of the flange portion 2a of the lens moving body 2 is formed outward in the radial direction, and the holding position of the magnetic piece 9 is set in the radial direction. Can be adjusted. Therefore, the magnetic attractive force generated between the drive magnet 6 and the magnetic piece 9 can be adjusted by adjusting the holding position of the magnetic piece 9. Accordingly, an appropriate magnetic attractive force can be set between the drive magnet 6 and the magnetic piece 9.

  In this embodiment, in a state where the lens moving body 2 is disposed inside the cylindrical portion of the fixed body 3, each magnetic piece 9 is disposed at the center position in the circumferential direction of the drive magnet 6. ing. Therefore, the magnetic piece 9 is attracted at the center position in the circumferential direction of the drive magnet 6 having a high magnetic flux density, and the lens moving body 2 can be stably held in the circumferential direction.

  Further, when the lens moving body 2 moves, even if the lens moving body 2 swings in the circumferential direction, a restoring force acts so that each magnetic piece 9 is arranged at the center position in the circumferential direction of the drive magnet 6. . Therefore, the optical characteristics of the lens group composed of the fixed lens 12 and the moving lenses 13 and 14 do not vary. As a result, the lens driving device 1 with stable optical characteristics can be provided.

(Other embodiments)
The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in the embodiment described above, the fixed body 3 is integrally formed in a bottomed cylindrical shape having a bottom portion and a cylindrical portion, but the cylindrical portion and the bottom portion of the fixed body may be configured separately. For example, the cylindrical member 31 shown in FIG. 6 and the bottom member 32 shown in FIG. 7 may be formed separately and combined to form a fixed body. In FIG. 7, the opening 32a, the yoke fixing part 32b, the fixing surface 32b1, the fitting convex part 32b2, the restricting concave part 32c, the extraction hole 32d, and the protrusion 32e are respectively the opening part 3a and the yoke fixing part 3b in FIG. This corresponds to the fixing surface 3b1, the fitting convex portion 3b2, the regulating concave portion 3c, the extraction hole 3d, and the protrusion 3e.

  In the embodiment described above, the fixed body 3 is formed from a resin member. However, a part or all of the fixed body 3 may be formed from a metal member. In this case, leakage of magnetic flux to the outside of the fixed body 3 can be reduced, and the driving efficiency of the driving means 4 can be increased.

  Furthermore, in the above-described embodiment, the three yokes 8 are fixed to the fixed body 3, but the yokes may be integrally formed in a ring shape like a yoke 38 shown in FIG. When the yoke is integrally formed like the yoke 38, the handling of the parts becomes easy and the assembling work becomes easy. In FIG. 8, the inner yoke 38a, the outer yoke 38b, the connecting portion 38c, the fitting hole 38d, and the fixed reference surface 38e are respectively the inner yoke 8a, the outer yoke 8b, the connecting portion 8c, and the fitting hole 8d in FIG. Corresponds to the fixed reference plane 8e.

  Furthermore, in the three yokes 8, as shown in FIG. 9, a thin plate-like cover 48 made of a magnetic member may be fixed to the upper ends of the inner yoke 8a and the outer yoke 8b in the figure by bonding or the like. In this case, an effective magnetic path is formed by the yoke 8 and the cover 48, and the driving efficiency of the driving means 4 can be increased.

  In the above-described embodiment, the driving coil 5 is disposed on the lens moving body 2 and the driving magnet 6 is disposed on the fixed body 3. However, the driving magnet 6 is disposed on the lens moving body 2 and the stationary body. 3 may be provided with a drive coil 5.

  Furthermore, the yoke is not necessarily provided with the outer yoke, and the yoke may be constituted by an inner yoke serving as a guide protrusion and a bottom surface provided with a fixed reference surface. The drive magnet may be a permanent magnet integrally formed in a ring shape.

  Furthermore, in the above-described embodiment, the sliding guide composed of the inner yoke 8a and the sliding hole 2b is formed at three locations in the circumferential direction. However, the sliding guide is not limited to three locations and is limited to two locations. You may form, and you may form in four or more places.

It is side surface sectional drawing which shows the lens drive device concerning embodiment of this invention. The fixed side member of the lens drive device shown in FIG. 1 is shown, (A) is the top view, (B) is sectional drawing in the AA cross section of (A). 1A and 1B show a fixed body of the lens driving device shown in FIG. 1, in which FIG. 1A is a top view thereof, and FIG. The yoke of the lens drive device shown in FIG. 1 is shown, (A) is a top view thereof, and (B) is a sectional view taken along the line CC of (A). 1A and 1B show a moving side member of the lens driving device shown in FIG. 1, in which FIG. 1A is a top view thereof, FIG. 1B is a cross-sectional view taken along a line DD in FIG. 1A, and FIG. It is a top view which shows the cylindrical member of the fixing body concerning the other form of this invention. The bottom member of the fixing body concerning the other form of this invention is shown, (A) is the top view, (B) is sectional drawing in the EE cross section of (A). It is a top view which shows the yoke concerning the other form of this invention. The yoke concerning the other form of this invention is shown, (A) is the top view, (B) is sectional drawing in the FF cross section of (A).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens drive device 2 Lens moving body 2b Sliding hole 2c Magnetic piece holding | maintenance part 3 Fixed body 3b, 32b Yoke fixing | fixed part 3b2, 32b2 Fitting convex part 4 Drive means 5 Drive coil 6 Drive magnet 8, 38 In yoke 8a, 38a Yoke (guide protrusion)
8b, 38b Outer yoke 8c, 38c Connecting portion 8d, 38d Fitting hole 9 Magnetic piece 12 Fixed lens 13, 14 Moving lens L Optical axis

Claims (8)

A lens driving device comprising: a lens moving body that holds a lens; a driving unit that moves the lens moving body in the optical axis direction of the lens; and a fixed body that supports the lens moving body so as to be movable in the optical axis direction. In
The drive means forms a magnetic circuit together with the drive coil disposed on one of the lens moving body and the fixed body, the drive magnet disposed on the other, and the drive coil and the drive magnet. A plate-like yoke disposed on the fixed body,
The yoke includes a guide protrusion extending in the optical axis direction for guiding the lens moving body in the optical axis direction, and the lens moving body is in sliding contact with the guide protrusion through which the guide protrusion is inserted. A lens driving device comprising a sliding hole.   The lens driving device according to claim 1, wherein the guide protrusion and the sliding hole are provided at a plurality of locations around the optical axis of the lens.   The yoke includes an inner yoke serving as the guide protrusion, an outer yoke formed outside the inner yoke in a direction perpendicular to the optical axis, and a connecting portion that connects the inner yoke and the outer yoke. The lens driving device according to claim 1, wherein the connecting portion is fixed to a yoke fixing portion formed on the fixed body.   The fitting portion for fixing the yoke is formed in the yoke fixing portion, and the fitting hole for fitting with the fitting projection is formed in the yoke. Item 4. The lens driving device according to Item 3.   The lens moving body is formed in a cylindrical shape, and the lens moving body holds the lens on the inner peripheral side, and the drive coil is wound on the outer peripheral side. Lens drive device.   The lens driving device according to claim 1, wherein a lubricating film is formed on at least one surface of the guide protrusion and the sliding hole.   The lens moving body or the fixed body provided with the drive coil includes a magnetic piece, and the lens is moved at the end of the movable range of the lens moving body by a magnetic attractive force between the magnetic piece and the drive magnet. The lens driving device according to claim 1, wherein the lens holding device is held.   In the lens moving body or the fixed body provided with the magnetic piece, a magnetic piece holding part extending in a direction perpendicular to the optical axis is formed to hold the magnetic piece, and the holding position of the magnetic piece is The lens driving device according to claim 7, wherein the lens driving device is configured to be adjustable in a direction orthogonal to the optical axis.

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