JP2012027086A - Manufacturing method of lens driving device, and lens driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate thrust necessary for moving a lens holder even when an inner circumferential wall part is not provided to a yoke.SOLUTION: A lens driving device 1 comprises: a lens holder 4 holding a lens; an annular shaped air-core coil 5 attached around the lens holder 4; a magnet 6 arranged to face the outer periphery of the air-core coil 5; and a magnet holder 7 on which a circular opening 72 for housing the lens holder 4 is formed and in which the magnet 6 is buried. The lens driving device 1 drives the lens in the optical axis direction by supplying power to the air-core coil 5. A pole face composed of a curved surface having the same shape as the inner peripheral surface regulating the opening 72 of the magnet holder 7 is provided to a part of the magnet 6, and the pole face and the inner peripheral surface regulating the opening 72 of the magnet holder 7 are made flush with each other.

Description

  The present invention relates to a method for manufacturing a lens driving device and a lens driving device, for example, a method for manufacturing a small lens driving device and a lens driving device to be mounted on a mobile phone device with a camera function.

  2. Description of the Related Art Conventionally, a small lens driving device mounted on a camera-equipped mobile phone device or the like includes a lens holder that holds a lens and a lens driving unit that moves the lens holder in the optical axis direction. There has been proposed an air core coil, a yoke arranged so as to cover the air core coil, and a magnet fixed to a part of the yoke (for example, see Patent Document 1).

  In this lens driving portion, the yoke has an outer peripheral wall portion and an inner peripheral wall portion, and an air core coil is positioned between the outer peripheral wall portion and the inner peripheral wall portion, and is provided so as to cover the air core coil. Yes. The magnet is fixed to the inner wall surface of the outer peripheral wall corresponding to the four corners of the yoke, while the magnetic pole surface is disposed at a position facing the inner peripheral wall of the yoke. The air core coil is disposed at a position between the magnetic pole surface of the magnet and the inner wall surface of the yoke. Since the magnetic flux generated on the magnetic pole surface of the magnet passes through the air-core coil and travels toward the inner peripheral wall, when the air-core coil is energized, a thrust (electromagnetic force) is generated that moves the air-core coil in the optical axis direction. Will be.

JP 2010-14938 A

  By the way, in the lens driving device described above, it has been studied to use a yoke without an inner peripheral wall portion from the viewpoint of reducing the manufacturing cost. When using a yoke that does not have an inner peripheral wall as described above, the thrust required for moving the lens holder can be obtained unless the distance between the magnetic pole surface of the magnet and the outer peripheral surface of the air-core coil is very close. I can't.

  The present invention has been made in view of such circumstances, and manufacture of a lens driving device capable of generating a thrust necessary for moving the lens holder even when the inner peripheral wall portion is not provided on the yoke. It is an object to provide a method and a lens driving device.

  The method for manufacturing a lens driving device according to the present invention includes a lens holder for holding a lens, an annular air core coil mounted around the lens holder, and an outer peripheral portion of the air core coil. And a magnet holder that holds the magnet and has a circular opening that accommodates the lens holder, and drives the lens in the optical axis direction by energizing the air-core coil. A method of manufacturing a drive device, the step of attaching a magnet having a magnetic pole surface corresponding to the shape of the outer peripheral surface to the outer peripheral surface of a reference diameter metal rod having an outer diameter larger than the outer diameter of the air-core coil; Forming the magnet holder by resin molding including a magnet and the reference diameter metal rod; removing the reference diameter metal rod from the molded body of the magnet holder; and removing the reference diameter metal rod. That it comprises a step of accommodating the lens holder into an opening formed to it said.

  According to the manufacturing method of the lens driving device, since the magnet disposed in the magnet holder is positioned with reference to the outer peripheral surface of the reference diameter metal rod, it is accommodated in the magnetic pole surface of the magnet and the opening of the magnet holder. Since the lens holder can be placed opposite to the outer peripheral surface of the air-core coil in the shortest distance, the thrust required to move the lens holder is generated even when the inner peripheral wall is not provided on the yoke. It becomes possible to make it.

  In the method for manufacturing the lens driving device, it is preferable that the magnet is magnetically attracted to the outer peripheral surface of the reference diameter metal rod. In this case, since the magnet holder can be resin-molded while the magnet is magnetically attracted to the reference diameter metal rod, it is easy to position the magnet and the processing required for manufacturing the magnet holder can be simplified. It becomes.

  In the method for manufacturing the lens driving device, it is preferable that the outer diameter of the outer peripheral surface of the reference diameter metal rod is slightly larger than the outer diameter of the air-core coil. In this case, since the inner peripheral surface of the opening in which the lens holder is accommodated can be formed slightly larger than the outer peripheral surface of the air-core coil, the empty space in the lens holder that is accommodated in the opening of the magnet holder. It becomes possible to arrange the outer peripheral surface of the core coil and the magnetic pole surface of the magnet in close proximity to each other and face each other.

  The lens driving device according to the present invention includes a lens holder that holds a lens, an annular air core coil that is mounted around the lens holder, and a magnet that is disposed to face the outer periphery of the air core coil. A magnet holder that holds the magnet and has a circular opening that accommodates the lens holder, and drives the lens in the optical axis direction by energizing the air-core coil. A magnetic pole surface having a curved surface having the same shape as the inner peripheral surface defining the opening of the magnet holder is provided in a part of the magnet, and the inner periphery defining the magnetic pole surface and the opening of the magnet holder. It is characterized in that the surfaces are flush with each other.

  According to the lens driving device, since the magnetic pole surface of the magnet is configured to be flush with the inner peripheral surface defining the opening of the magnet holder, the lens holder accommodated in the magnetic pole surface of the magnet and the opening of the magnet holder Since the distance from the outer peripheral surface of the air-core coil can be opposed to each other, the thrust required for moving the lens holder can be generated even when the inner peripheral wall portion is not provided on the yoke. It becomes possible.

  According to the present invention, even when the inner peripheral wall portion is not provided on the yoke, it is possible to generate a thrust necessary for moving the lens holder.

It is a disassembled perspective view of the lens drive device which concerns on one embodiment of this invention. It is a whole perspective view of the lens drive device concerning the above-mentioned embodiment. It is sectional drawing of the lens drive device which concerns on the said embodiment. It is a perspective view of the magnet which the lens drive device concerning the above-mentioned embodiment has. It is a perspective view of the magnet holder which the lens drive device concerning the above-mentioned embodiment has. It is explanatory drawing of the manufacturing process of the lens drive device which concerns on the said embodiment. It is explanatory drawing of the manufacturing process of the lens drive device which concerns on the said embodiment. It is sectional drawing of the magnet holder of the lens drive device which concerns on the said embodiment. It is sectional drawing of the lens drive device which concerns on the said embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The lens driving device manufactured by the manufacturing method according to the present embodiment is mounted on, for example, a mobile phone device with a camera function. Note that the device on which the lens driving device according to the present embodiment is mounted is not limited to this and can be changed as appropriate.

  FIG. 1 is an exploded perspective view of a lens driving device 1 according to an embodiment of the present invention. FIG. 2 is an overall perspective view of the lens driving device 1 according to the embodiment of the present invention. FIG. 3 is a cross-sectional view of the lens driving device 1 according to the present embodiment. As shown in FIGS. 1 to 3, the lens driving device 1 according to the present embodiment is mounted on a substrate on which an image sensor (not shown) is mounted in a state where a lens (not shown) is mounted at the center of the device. On the other hand, the focal length is adjusted by driving the lens in the optical axis direction.

  As shown in FIG. 1, the lens driving device 1 includes a lower case 3 fitted with a lower leaf spring 2, a lens holder 4 placed on the lower case 3, and an annular air core fixed to the lens holder 4. The coil 5 is fixed to the magnet holder 7 with the magnet holder 7 holding the plurality of magnets 6, the yoke 8 disposed around the magnet holder 7, the upper leaf spring 9 and the inner plate 10 being interposed. The top cover 11 is assembled.

  The lower case 3 is composed of a rectangular plate-like member, and a circular opening 31 is formed at the center. At the four corners of the lower case 3, generally L-shaped projecting portions 32 projecting upward are formed. These protrusions 32 position the yoke 8 in the front / rear and left / right directions. Further, boss portions 33 projecting upward are formed inside the projecting portions 32 formed at the four corners. The lower leaf spring 2 is positioned by these boss portions 33 and fixed to the lower case 3.

  The lower leaf spring 2 is made of an elastic metal plate, and has an annular spring portion 22 having an opening portion 21 having a diameter larger than the opening portion 31 of the lower case 3 at the center, and a flat plate shape to which the spring portion 22 is connected. And a fixing portion 23. At a predetermined position of the spring portion 22, a plurality of engagement holes 24 for fixing engagement pins (not shown) provided at the lower end portion of the lens holder 4 are provided. The fixed portion 23 has a generally rectangular outer shape, and insertion holes 25 into which the boss portions 33 of the lower case 3 are inserted are formed at the four corners. The lower leaf spring 2 supports the lens holder 4 from below while being fixed to the lower case 3.

  A conductive member 12 configured to straddle a pair of adjacent insertion holes 24 is overlaid on the lower leaf spring 2. The conducting member 12 is formed of a long metal plate material having conductivity, and one end of the air-core coil 5 is connected to a predetermined position. A pair of insertion holes 121 into which the boss portion 33 of the lower case 3 is inserted is formed at the end of the conducting member 12. In addition, a terminal portion 122 that is bent downward is provided at one end of the conducting member 12. The terminal portion 122 is fixed to the substrate on which the lens driving device 1 is mounted by soldering or the like.

  The lens holder 4 has a cylindrical portion 41 having a generally cylindrical shape. A coil holding portion 42 that holds the air-core coil 5 is provided on the outer peripheral surface of the cylindrical portion 41. An internal thread portion 43 is formed on the inner peripheral surface of the tubular portion 41. A lens unit including a lens (not shown) is attached to the female screw portion 43. A plurality of engagement pins 44 that are fixed to engagement holes 94 of an upper leaf spring 9 to be described later are provided on the upper end portion of the tubular portion 41. Although not shown, a plurality of engagement pins that are fixed to the engagement holes 24 of the lower leaf spring 2 are provided at the lower end portion of the tubular portion 41.

  The magnet holder 7 has, for example, a holder body 71 that is formed of an insulating resin material and is generally rectangular in top view. An opening 72 having a diameter larger than that of the outer peripheral surface of the lens holder 4 is provided at the center of the holder main body 71. In the vicinity of the center of the upper end portion of each side surface portion of the holder main body portion 71, an engaging portion 73 is provided so as to protrude laterally. These engaging portions 73 are configured to be engageable with a notch portion 81 of the yoke 8 described later. Boss portions 74 that protrude upward are formed at the four corners of the upper surface of the holder main body 71. The upper leaf spring 9, the inner plate 10 and the top cover 11 are positioned by these boss portions 74 and fixed to the magnet holder 7.

  The magnet 6 is disposed inside the magnet holder 7 so that a part of the magnet 6 is exposed from an inner peripheral surface that defines the opening 72 of the magnet holder 7 (hereinafter referred to as “the inner peripheral surface of the magnet holder 7” as appropriate). Yes. The magnets 6 are arranged in the vertical direction at each position corresponding to the four corners of the magnet holder 7. These magnets 6 are embedded in predetermined positions of the magnet holder 7 when the magnet holder 7 is molded. In addition, arrangement | positioning of the magnet 6 in the magnet holder 7 and the shaping | molding method of the magnet holder 7 are mentioned later.

  The yoke 8 is composed of a frame formed of a conductive metal plate material. The yoke 8 is configured to cover the entire surface of the side surface of the magnet holder 7 with a certain distance therebetween. A notch 81 that accommodates the engaging portion 73 of the magnet holder 7 is formed at the center of the upper end of each surface of the yoke 8. The magnet holder 7 is positioned at a predetermined position in the yoke 8 by accommodating the engaging portion 73 with these notches 81.

  The upper leaf spring 9 is made of a rectangular metal plate having elasticity, and an annular spring portion 92 having an opening portion 91 having substantially the same diameter as the opening portion 21 of the lower leaf spring 2 is connected to the spring portion 92. And a flat plate-like fixing portion 93. A plurality of engagement holes 94 for fixing the engagement pins 44 provided at the upper end portion of the lens holder 4 are provided at predetermined positions of the spring portion 92. The fixed portion 93 has a generally rectangular outer shape, and insertion holes 95 into which the boss portions 74 of the magnet holder 7 are inserted are formed at the four corners. The upper leaf spring 9 supports the lens holder 4 from above while being fixed to the magnet holder 7.

  The inner plate 10 includes an annular portion 102 having an opening 101 having a larger diameter than the opening 91 of the upper leaf spring 9 at the center. The outer shape of the annular portion 102 is generally rectangular, and insertion holes 103 into which the boss portions 74 of the magnet holder 7 are inserted are formed at the four corners.

  A conductive member 13 is superimposed on the inner plate 10 at a position corresponding to the specific insertion hole 103. The conducting member 13 is made of a conductive metal plate, and the other end of the air-core coil 5 (the other end different from the one connected to the conducting member 12) is connected to a predetermined position. An insertion hole 131 into which the boss 74 of the magnet holder 7 is inserted is formed in the conduction member 13. The conducting member 13 is provided with a terminal portion 132 that is bent downward. The terminal portion 132 is fixed to the substrate on which the lens driving device 1 is mounted by soldering or the like.

  The top cover 11 includes a rectangular plate-like portion 112 having a circular opening 111 at the center. Although not shown, a plurality of fitting holes into which the boss portions 74 of the magnet holder 7 are fitted are provided on the lower surface of the top cover 11. The top cover 11 is attached to the magnet holder 7 by fitting the boss portion 74 of the magnet holder 7 to which the upper plate spring 9 and the inner plate 10 are attached into the fitting holes.

  With this configuration, in the lens driving device 1, the lower case spring 2 is mounted with the spring portion 22 of the lower leaf spring 2, and the lens holder 4 holding the air-core coil 5 is mounted on the lower leaf spring 2. . Then, the yoke 8 is placed on the lower case 3 in a state where it is positioned by the protruding portion 32, and is fixed to the lower case 3 with an adhesive or the like. Further, the magnet holder 7 is accommodated in the yoke 8 so as to accommodate the lens holder 4 in the opening 72, and is fixed to the lower case 3 with an adhesive or the like. Thus, the upper leaf spring 9 is mounted on the upper surface of the magnet holder 7 accommodated in the yoke 8. After the lens holder 4 is mounted on the spring portion 92 of the upper plate spring 9, the top cover 11 is mounted on the magnet holder 7 with the inner plate 10 being superimposed on the upper plate spring 9.

  In the lens driving device 1 assembled in this way, as shown in FIG. 3, the lens holder 4 is supported by the lower leaf spring 2 and the upper leaf spring 9 mounted on the lower case 3 and the magnet holder 7, respectively. The air-core coil 5 held by the lens holder 4 is disposed so as to face the inner peripheral surface of the magnet holder 7 with a slight gap therebetween. At the four corners of the lens driving device 1, the magnetic pole surface of the magnet 6 embedded in the magnet holder 7 and the outer peripheral surface of the air-core coil 5 are arranged to face each other.

  The magnetic flux generated on the magnetic pole surface of the magnet 6 passes through the air-core coil 5 and then travels toward the upper end or lower end of the yoke 8 shown in FIG. For this reason, when the air-core coil 5 is energized, a thrust (electromagnetic force) that causes the air-core coil 5 to move in the optical axis direction is generated. Therefore, the thrust generated in the air-core coil 5 can be controlled by controlling the energization amount to the air-core coil 5. As a result, the lens holder 4 to which the lens unit is mounted can be moved in the optical axis direction, and the focal length of the lens with respect to the image sensor can be adjusted.

  Here, the configuration of the magnet 6 included in the lens driving device 1 according to the present embodiment and the arrangement of the magnet 6 in the magnet holder 7 will be described with reference to FIGS. 4 and 5. FIG. 4 is a perspective view of the magnet 6 included in the lens driving device 1 according to the present embodiment. FIG. 5 is a perspective view of the magnet holder 7 included in the lens driving device 1 according to the present embodiment.

  As shown in FIG. 4, the magnet 6 included in the lens driving device 1 according to this embodiment includes a pair of orthogonal side surfaces 61 and 62, and magnetic poles that connect the end portions of these side surfaces 61 and the end surfaces of the side surfaces 62. And a surface 63. The magnetic pole surface 63 of each magnet 6 is formed of the same curved surface as the inner peripheral surface of the magnet holder 7 and has a shape corresponding to the outer peripheral surface of a reference diameter metal rod 14 to be described later.

  As shown in FIG. 5, each magnet 6 is disposed at a position corresponding to the four corners of the magnet holder 7 so that the magnetic pole surface 63 is exposed to the inside from the inner peripheral surface of the magnet holder 7. Each magnet 6 is disposed at a predetermined position in the holder main body 71 when the holder main body 71 of the magnet holder 7 is molded.

  Here, a manufacturing method of the lens driving device 1 according to the present embodiment will be described with reference to FIGS. 6 and 7 are explanatory diagrams of the manufacturing process of the lens driving device 1 according to the present embodiment. 6 and 7 show the molding process of the magnet holder 7 included in the lens driving device 1. In particular, FIG. 6 shows a state before the holder body 71 of the magnet holder 7 is molded, and FIG. 7 shows a state after the holder body 71 of the magnet holder 7 is molded. Here, it is assumed that the magnet 6 is magnetized in the pre-process of the molding process in the holder main body 71 of the magnet holder 7.

  When generating the magnet holder 7 according to the present embodiment, first, a reference diameter metal rod 14 serving as a reference when the magnet 6 is arranged is prepared. The reference diameter metal bar 14 is composed of a metal bar having an outer diameter slightly larger than the outer diameter of the air-core coil 5 attached to the lens holder 4. And as shown in FIG. 6, it attaches so that the magnetic pole surface 63 of the magnet 6 may magnetically adsorb | suck to the predetermined position of the outer peripheral surface of the reference | standard diameter metal rod 14. As shown in FIG. In this case, the plurality of magnets 6 are arranged at the same height in the axial direction of the reference diameter metal rod 14, and the upper and lower surfaces shown in FIG. 6 of each magnet 6 coincide with the upper and lower surfaces of the other magnets 6. It is attached as follows.

  In this way, a part of the reference-diameter metal rod 14 on which the magnet 6 is magnetically attracted (a portion where the magnet 6 is disposed) is disposed in a mold (not shown). Then, a resin material is injected into the mold, and the holder main body 71 is molded at a position including the magnet 6 and a part of the reference diameter metal rod 14 corresponding to the magnet 6. In this case, as shown in FIG. 7, the holder main body 71 is molded around the reference diameter metal rod 14 including the position corresponding to the magnet 6.

  After the resin material injected into the mold is solidified, the reference diameter metal rod 14 is removed from the holder main body 71. Thus, the magnet holder 7 shown in FIG. 5 is formed by removing the reference diameter metal bar 14. An opening 72 of the magnet holder 7 is formed in the portion where the reference diameter metal rod 14 is removed. In the magnet holder 7 formed in this way, the magnet 6 is positioned with reference to the reference diameter metal rod 14 used for forming the opening 72, so that the inner peripheral surface defining the opening 72 is used as a reference. It can be said that it is positioned. In this case, for example, it is possible to ensure positional accuracy with the air-core coil 5 disposed in the opening 72 as compared with the case where the positioning is performed with the outer wall surface of the magnet holder 7 as a reference.

  FIG. 8 is a cross-sectional view of the magnet holder 7 formed by the steps shown in FIGS. 6 and 7. In addition, in FIG. 8, sectional drawing at the time of cut | disconnecting the position corresponding to the magnet 6 to a horizontal direction is shown. In the case where the magnet holder 7 is formed by the process as described above, the holder main body 71 is molded in a state where the magnet 6 is positioned on the reference diameter metal rod 14. Therefore, as shown in FIG. 8, the magnet 6 is disposed in the magnet holder 7 with the magnetic pole surface 63 constituting a part of the inner peripheral surface that defines the opening 72 of the magnet holder 7. In this case, in the magnet holder 7, the magnetic pole surface 63 is configured to be flush with the inner peripheral surface that defines the opening 72.

  The manufacturing method of the lens driving device 1 according to the present embodiment includes the step of housing the lens holder 4 in the opening 72 formed by removing the reference diameter metal rod 14 as described above. In the opening 72 thus formed, the lens holder 4 is accommodated as shown in FIG.

  FIG. 9 is a cross-sectional view of the lens driving device 1 according to the present embodiment. In addition, in FIG. 9, sectional drawing in the same surface as the cross section of the magnet holder 7 shown in FIG. 8 is shown. As shown in FIG. 9, the lens holder 4 is accommodated in the opening 72 of the magnet holder 7. The reference diameter metal rod 14 used for forming the opening 72 has an outer diameter slightly larger than the outer peripheral portion of the air-core coil 5 attached to the lens holder 4. For this reason, the magnetic pole surface 63 of the magnet 6 disposed in the magnet holder 7 is disposed to face the outer peripheral portion of the air-core coil 5 mounted on the lens holder 4 with a slight clearance.

  As described above, in the method for manufacturing the lens driving device 1 according to the present embodiment, the magnet 6 disposed in the magnet holder 7 is positioned with reference to the reference diameter metal rod 14, and thus the magnetic pole surface 63 of the magnet 6. And the lens holder 4 accommodated in the opening 72 of the magnet holder 7 can be opposed to each other with the distance from the outer peripheral surface of the air-core coil 5 minimized, so that no inner peripheral wall portion is provided on the yoke 8. Even in this case, it is possible to generate a thrust necessary for the movement of the lens holder 4.

  Further, in the lens driving device 1 manufactured by the manufacturing method of the lens driving device 1 according to the present embodiment, the magnetic pole surface 63 of the magnet 6 and the inner peripheral surface that defines the opening 72 of the magnet holder 7 are surfaces. Therefore, the magnetic pole surface 63 of the magnet 6 and the lens holder 4 accommodated in the opening 72 of the magnet holder 7 are opposed to each other with the distance between the outer peripheral surface of the air-core coil 5 minimized. Therefore, even when the yoke 8 is not provided with the inner peripheral wall portion, it is possible to generate a thrust necessary for the movement of the lens holder 4.

  In particular, in the method of manufacturing the lens driving device 1 according to the present embodiment, the magnet 6 is magnetically attracted to the outer peripheral surface of the reference diameter metal rod 14, so that the magnet 6 is magnetically attracted to the reference diameter metal rod 14. Since the magnet holder 7 can be resin-molded in a state in which the magnet holder 7 has been placed, the magnet 6 can be easily positioned, and the processing required for manufacturing the magnet holder 7 can be simplified.

  Further, in the manufacturing method of the lens driving device 1 according to the present embodiment, the outer diameter of the outer peripheral surface of the reference diameter metal rod 14 is slightly larger than the outer diameter of the air-core coil 5, and therefore the lens holder 7. Can be formed slightly larger than the outer peripheral surface of the air core coil 5, so that the air core in the lens holder 7 accommodated in the opening 72 of the magnet holder 7 can be formed. It becomes possible to arrange the outer peripheral surface of the coil 5 and the magnetic pole surface 63 of the magnet 6 in close proximity to each other and to face each other.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously. In the above-described embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  For example, in the above-described embodiment, the case where resin molding is performed in a state where the magnet 6 magnetized in the previous process is magnetically attracted in the molding process of the magnet holder 7 is described. Is not limited to this, and can be changed as appropriate. For example, the magnet 6 (magnetic material) before being magnetized is attached to the reference diameter metal rod 14 with an adhesive or the like, or is supported on the reference diameter metal rod 14 with a jig or the like equipped on the mold It is also possible to resin-mold the magnet holder 7. In this case, although it is necessary to apply an adhesive or the like or to equip the mold with a jig or the like, it is possible to obtain the same effect as the above embodiment.

DESCRIPTION OF SYMBOLS 1 Lens drive device 2 Lower leaf | plate spring 3 Lower case 4 Lens holder 41 Cylindrical part 42 Coil holding part 5 Air core coil 6 Magnet 61, 62 Side surface 63 Magnetic pole surface 7 Magnet holder 71 Holder main-body part 72 Opening part 8 York 9 Upper leaf | plate spring 10 Internal plate 11 Top cover

Claims (4)

A lens holder for holding the lens, an annular air core coil mounted around the lens holder, a magnet disposed opposite to the outer periphery of the air core coil, and holding the magnet A manufacturing method of a lens driving device including a magnet holder formed with a circular opening for accommodating the lens holder, and driving the lens in an optical axis direction by energizing the air-core coil;
Attaching a magnet having a magnetic pole surface corresponding to the shape of the outer peripheral surface to the outer peripheral surface of a reference diameter metal rod having an outer diameter larger than the outer diameter of the air-core coil; and the magnet and the reference diameter metal rod. Including the step of forming the magnet holder by resin molding, the step of removing the reference diameter metal rod from the molded body of the magnet holder, and the lens holder in the opening formed by removing the reference diameter metal rod And a step of housing the lens driving device.   2. The method for manufacturing a lens driving device according to claim 1, wherein the magnet is magnetically attracted to an outer peripheral surface of the metal rod having the reference diameter.   3. The method for manufacturing a lens driving device according to claim 1, wherein the outer diameter of the outer peripheral surface of the metal rod of the reference diameter is slightly larger than the outer diameter of the air-core coil. A lens holder for holding the lens, an annular air core coil mounted around the lens holder, a magnet disposed opposite to the outer periphery of the air core coil, and holding the magnet A lens driving device comprising a magnet holder formed with a circular opening for accommodating the lens holder, and driving the lens in the optical axis direction by energizing the air-core coil,
A magnetic pole surface comprising a curved surface having the same shape as the inner peripheral surface defining the opening of the magnet holder is provided in a part of the magnet, and the magnetic pole surface and an inner peripheral surface defining the opening of the magnet holder are provided. A lens driving device characterized by being configured to be flush with each other.

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