JP2008299286A - Lens driving device and method for assembling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the thrust of a lens barrel to a base by contriving the lens barrel outside diameter structure, and to miniaturize an actuator for driving a lens. <P>SOLUTION: This lens driving device includes: a lens barrel 60 which is formed as a stepped cylindrical body 61 housing lenses 71, 72, 73 different in aperture and movably disposed on the base 10; a coil 30 disposed and fixed on the middle-stage outer peripheral part of the stepped cylindrical body 61; a yoke 40 disposed on the above outer peripheral part and fixed to the base 10; and a magnet 50 disposed and fixed on the above inner peripheral part, wherein a part or the whole of the yoke 40 is folded back and disposed in outer peripheral part of the stepped cylindrical body 61, and the lens barrel 60 is assembled to hold the coil 30 between an inner yoke part 42 disposed in the middle-stage outer peripheral part 65 and the magnet 50 disposed and fixed on the inner yoke part 42. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lens driving device applicable to a lens unit for a camera module such as a digital camera, a video camera, and a mobile phone, and an assembling method thereof. Specifically, when a lens with a different diameter stored in a lens barrel is driven with respect to the base, it is arranged on the outer periphery of the lens barrel that forms a stepped cylindrical body by folding back part or all of the edge of the yoke. The lens barrel is assembled so that the coil is sandwiched between the yoke and the magnet arranged and fixed inside the yoke, and the yoke arranged on the outer periphery of the stepped cylindrical body forms a closed magnetic circuit including the magnet and the coil. The magnetic flux generated by the magnet can be sufficiently linked to the coil.

  In recent years, a lens unit is mounted on a camera module such as a digital camera, a video camera, or a mobile phone, and a lens driving device (hereinafter also referred to as a lens actuator) for autofocus (AF) is used for the lens unit. There are many cases. This type of lens actuator drives the lens barrel in units of several microns with respect to the base when adjusting the focus of the lens housed in the lens barrel.

  FIG. 10 is a cross-sectional view showing a configuration example of a lens unit 200 according to a conventional example for autofocus (AF). A lens unit 200 shown in FIG. 10 includes a lens actuator 11 of a linear drive system (for example, a moving coil system) used for a general camera module. The lens actuator 11 is provided on the base 10 'covered with the cover member 80'.

  The lens actuator 11 includes three parts: a movable part side composed of a lens barrel 60 ′ and a coil 13, a fixed part side part composed of a base 10 ′, a yoke 14 and a magnet 15, and an elastic member (not shown) for connecting them. Configuration is adopted. The elastic member is omitted for simplicity of explanation. The lens barrel 60 'houses a combined lens body 70, a diaphragm 74, a spacer 75, and the like that are a combination of lenses 71, 72, and 73 having different diameters. As for the outer diameters of a plurality of lenses inserted into the lens barrel, those closest to the imaging surface generally have the largest aperture.

  The outer diameter of the lens barrel 60 'is determined by the largest lens outer diameter. In the figure, φ: Coil is the outer diameter of the coil 13, and φ: Barrel # 0 is the outer diameter of the lens barrel 60 '. In the lens actuator 11, φ: Coil> φ: Barrel # 0 is set.

  Further, according to the lens actuator 11, the thrust generated by passing a current through the coil 13 at the time of lens focus adjustment is controlled by the elastic member for the operation of the component on the movable unit side with respect to the component on the fixed unit side. It acts to finely adjust the lens barrel 60 '(autofocus operation).

  Regarding a lens unit including this type of actuator, Patent Document 1 discloses an electromagnetic drive device and a focus control device using the electromagnetic drive device. According to this electromagnetic drive device, the lens holder, the coil, the outer yoke tube portion, and the inner yoke tube portion are provided. The lens holder has a rectangular shape, and holds the lens at four diagonal corners. The coil is wound around the outer periphery of a rectangular holder. As for the yoke, the outer yoke cylinder part and the inner yoke cylinder part are formed concentrically. A magnet is fixed to one of the cylindrical portions of the yoke, and both the yoke and the magnet constitute a closed magnetic path, and a coil wound around the lens holder is interposed between the yokes.

Japanese Patent Laid-Open No. 7-146430 (FIG. 1 on page 7)

Incidentally, the lens driving device according to the conventional example has the following problems.
i. Currently, the lens barrel of the mainstream lens actuator is often screwed into another part, for example, a holder (the outside is a screw shape). By the way, when the holder part and its screw part are deleted and an inner yoke part whose whole or part of the edge part is folded is arranged in the outer diameter direction of the lens barrel, a step is provided on the screw part. It is difficult.

  ii. According to the lens actuator 11 shown in FIG. 10, since the inner yoke portion 42 ′ facing the magnet 50 is provided, the entire actuator becomes large. When the lens actuator 11 is further reduced in size, it becomes more difficult to dispose the inner yoke portion 42 ′ facing the magnet 50.

  iii. In addition, there is a demand to set a large lens aperture instead of shortening the distance (optical length) between the lenses when it is necessary to use a large image sensor or the lens unit 200 is thinned. In the case of the yoke structure having the outer yoke cylinder part and the inner yoke cylinder part as found in Patent Document 1, the closed magnetic path is formed in the peripheral part of the rectangular lens holder. Therefore, it becomes difficult to provide an ultra-compact camera equipped with a large-diameter lens. An attempt to increase the effective diameter of each lens results in an increase in the lens outer diameter.

  iv. As the lens outer diameter increases, the size of the magnetic circuit for the autofocus function disposed around the movable part is also greatly influenced by the outer diameter of the lens barrel 60 '. Incidentally, it is conceivable to reduce the size of the magnetic circuit and delete a part of the yoke 14 (inner yoke portion, etc.) to reduce the size in the radial direction. The thrust cannot be ensured and the leakage magnetic flux also increases, and there is a concern that it may adversely affect other parts of the mobile device using magnetism.

  Therefore, the present invention solves such a conventional problem, and devise the outer diameter structure of the lens barrel so that the thrust of the lens barrel with respect to the base can be improved, and an actuator for driving the lens is provided. It is an object of the present invention to provide a lens driving device and an assembling method thereof that can be miniaturized.

  The above-described problem is a lens driving device that drives a lens accommodated in a lens barrel with respect to a base, and is configured to be movable with respect to the base by forming a stepped cylindrical body that accommodates lenses of different diameters. The lens barrel arranged, the coil arranged and fixed on the outer peripheral part of the stepped cylindrical body, the support member arranged on the outer peripheral part of the coil and fixed to the base, and the inner peripheral part of the support member And a magnetic body disposed and fixed to the support member, and a part or all of the edge of the support member is folded back and disposed on the outer peripheral portion of the stepped cylindrical body, and the support disposed on the outer peripheral portion of the stepped cylindrical body This is solved by a lens driving device in which a lens barrel is incorporated so as to sandwich a coil between a member and a magnetic body arranged and fixed to the support member.

  According to the lens driving device of the present invention, when the lens housed in the lens barrel is driven with respect to the base, the support member disposed on the outer peripheral portion of the stepped cylindrical body of the lens barrel is a magnetic material, A closed magnetic circuit including a coil is formed. Therefore, the magnetic flux from the magnetic material can be sufficiently linked to the coil.

  An assembling method of a lens driving device according to the present invention is an assembling method of a lens driving device for driving a lens housed in a lens barrel with respect to a base, and a stepped cylindrical body for a lens barrel having a different diameter. And the step of arranging and fixing the coil on the outer peripheral portion of the stepped cylindrical body, the step of arranging the magnetic body on the inner peripheral portion and fixing it, and folding back part or all of the edge portion to make the stepped cylinder The support member is disposed on the outer peripheral portion of the cylindrical body, the support member disposed on the outer peripheral portion of the stepped cylindrical body, and the magnetic body disposed and fixed on the support member so as to sandwich the coil with respect to the base And a step of incorporating the stepped cylindrical body movably and a step of fixing the support member to the base.

  According to the assembling method of the lens driving device according to the present invention, the coil is sandwiched between the support member disposed on the outer peripheral portion of the stepped cylindrical body for the lens barrel and the magnetic body disposed and fixed on the support member. A lens barrel is incorporated movably with respect to the base. As a result, the holder part for attaching the lens barrel and the screw part thereof as in the conventional method can be omitted, so that the edge part is placed in the extra space in the outer diameter direction of the lens barrel from which the holder part and the screw part are removed. It is possible to adopt a holder integrated structure in which a support member that is partially or entirely folded is disposed.

  According to the lens driving device and the method of assembling the same according to the present invention, when the lens housed in the lens barrel is driven with respect to the base, the support member in which a part or all of the edge portion is folded is used for the lens barrel. The lens barrel is incorporated so that the coil is sandwiched between the support member disposed on the outer peripheral portion of the step cylindrical body and the magnetic body disposed and fixed on the support member. Is.

  With this configuration, the support member disposed on the outer periphery of the stepped cylindrical body of the lens barrel forms a closed magnetic path including the magnetic body and the coil, so that the magnetic flux from the magnetic body can be sufficiently linked to the coil. It becomes like this. Therefore, the thrust of the lens barrel with respect to the base (electromagnetic force due to the magnetic body and the coil) can be improved. In addition, since the holder part for attaching the lens barrel and its screw part as in the conventional method can be omitted, a part of the edge part is provided in the extra space in the middle outer periphery of the lens barrel from which the holder part and the screw part are removed. Or the holder integrated structure which has arrange | positioned the support member by which all was turned back can be taken. As a result, a small, thin and low power consumption lens driving device can be provided.

  Subsequently, an embodiment of a lens driving device and an assembling method thereof according to the present invention will be described with reference to the drawings.

  FIG. 1 is a partially crushed perspective view showing a configuration example of a lens unit 100 as an embodiment according to the present invention.

  In the lens unit 100 shown in FIG. 1, a lens barrel 60 having a stepped cylindrical body 61 accommodates a combined lens body 70 having different diameters. The lens barrel 60 is attached to a circular base 10 (base). It is a device to drive. The lens unit 100 includes a lens actuator 1 for a camera module that constitutes a function of a lens driving device. The lens actuator 1 is mounted on the base 10 and is assembled so as to cover the upper part with a circular cover member 80 having an opening 81. The lens unit 100 can be applied to a lens unit for a camera module such as a digital camera, a video camera, or a mobile phone. In the figure, I is a magnetic circuit, and hε is an outer diameter step (see FIG. 2).

  The lens actuator 1 includes a base 10, a coil 30, a yoke 40, a magnet 50 and a lens barrel 60. The coil 30 and the lens barrel 60 constitute parts on the movable part side of the lens actuator 1. The lens barrel 60 forms a stepped cylindrical body 61 with a hook that is movably disposed with respect to the base 10. For example, a lens assembly 70 including three lenses 71, 72, and 73 is accommodated. , Hold this together. In this example, the lenses 71 and 72 are in contact with the inner top surface of the lens barrel 60 and are supported on the S1 surface of the lens 73 via a spacer 75. The S1 surface of the lens 73 is flatter than the S2 surface that forms the convex portion on the imaging side.

  The inner side of the stepped cylindrical body 61 forms a first inner cylindrical portion 62 and a second inner cylindrical portion 63 having different inner diameters. Two lenses 71 and 72 and a diaphragm portion 74 are incorporated in the inner cylindrical portion 62. In this example, the diaphragm 74 is sandwiched between the lens 71 and the lens 72. A lens 73 is incorporated in the inner cylindrical portion 63 (see FIG. 2). As the material of the lens barrel 60, carbon fiber-containing resin, light metal, aluminum die casting, or the like is used.

  The outside of the stepped cylindrical body 61 has a bowl-shaped first outer edge portion (hereinafter referred to as a lower outer peripheral portion 64) below and a step-shaped second outer edge portion (hereinafter referred to as a middle step outer peripheral portion 65) in the middle. ) (See FIG. 4A). The coil 30 is disposed and fixed to the lower outer peripheral portion 64. For example, the coil 30 is wound around the lower outer peripheral portion 64 of the lens barrel 60 in a cylindrical shape. A copper wire having a predetermined wire diameter is used for the coil 30, and the coil 30 uses the lower outer peripheral portion 64 of the stepped cylindrical body 61 as a winding shaft portion. The number of turns of the coil 30 is N, and the number of layers is M. The coil 30 is energized during lens focus adjustment.

  The base 10, the yoke 40, and the magnet 50 described above, including the cover member 80, constitute parts on the fixed portion side of the base 10. For the cover member 80, for example, an aluminum plate is pressed into a circular shape, an opening 81 is formed in the center thereof, and the surface is subjected to a decorative design chrome plating or the like. The

  In this example, the circular cover member 80 is applied in combination with the cylindrical base 10. A yoke 40 is attached to the base 10. For the base 10, for example, a cylindrical body in which resin is molded is used. As the material of the base 10, resin, light metal, aluminum die casting or the like is used.

  In this example, a yoke 40 constituting an example of a support member is disposed on the outer peripheral portion of the coil 30 of the lens barrel 60 and is fixed to the base 10. The inner peripheral side of the yoke 40 is folded, for example, in an inverted U shape, and extends to the middle outer peripheral portion 65 of the lens barrel 60 described above. The yoke 40 includes an outer yoke portion 41 and an inner yoke portion 42. The outer yoke portion 41 is disposed on the outer peripheral portion of the coil 30 and constitutes a portion fixed to the base 10. The inner yoke portion 42 constitutes a portion in which the entire upper end of the yoke 40 is folded back inside, and extends into the middle outer peripheral portion 65 of the lens barrel 60. Of course, a part of the upper tip of the yoke 40 may be folded back inward.

  For the yoke 40, for example, an SPC (cold rolled steel plate) having a predetermined thickness is used. SPC is subjected to surface treatment (trivalent chromate treatment) by zinc (Zn) plating. Electroless plating (EL / FeP− / OP3) is employed for the surface treatment. A magnet 50 constituting an example of a magnetic body is disposed and fixed on the inner peripheral portion of the yoke 40. For example, an adhesive is applied to the side surface of the magnet 50, and is bonded to the yoke 40 via the adhesive and fastened and fixed. As the magnet 50, a flat cylindrical NdFeB (neodymium) sintered magnet, a ferrite magnet, an alnico magnet, or the like that is surface-treated by nickel (Ni) plating is used.

  In this example, the lens barrel 60 is assembled so that the coil 30 is sandwiched between the inner yoke portion 42 extending on the middle outer peripheral portion 65 and the magnet 50 arranged and fixed on the outer yoke portion 42 of the yoke 40. The above-described base 10 is fixed in a camera body (not shown), and an image sensor is mounted in the camera body. The image pickup device picks up a subject image formed by the combined lens body 70 of the lens barrel 60 after focus adjustment.

  FIG. 2 is a cross-sectional view supplementing a configuration example of the lens unit 100. According to the lens unit 100 shown in FIG. 2, in order to obtain the stepped cylindrical body 61, the object side (upper side in the figure) is more than the S1 surface of the lens 73 closest to the imaging surface in the optical axis direction of the lens barrel 60. ) Is provided with an outer diameter step hε. Here, when the height from the imaging surface to the S1 surface of the lens 73 is h1, and the height from the imaging surface to the middle outer periphery 65 of the lens barrel 60 is h2, the height h1 of the S1 surface and the middle outer periphery 65 The relationship of the height h1 of the S1 surface <the height h2 of the middle stage outer peripheral portion 65 is set between the height h2. The outer diameter step hε is determined by the height h1 of the height h2-S1 surface of the middle stage outer peripheral portion 65.

Further, when a plane perpendicular to the optical axis of the lens 73 is defined, the outer diameter (Barrel # 1) of the rising portion of the middle stage outer peripheral portion 65 of the lens barrel 60 is φ1 in the plane, and the outside of the lens 73 is When the diameter (Lens # 73) is φ2 and the outer diameter (Barrel # 0) of the rising portion of the lower outer peripheral portion 64 of the lens barrel 60 is φ3, the three outer diameters φ1, φ2, φ3 ,
{Φ3: (Barrel # 0)> φ2: (Lens # 73)> φ1: (Barrel # 1)}
Is set to a relationship. As a result, the middle stage outer peripheral portion 65 having a step difference φ1 smaller in the inner direction than the outer diameter φ2 of the lens 73 can be set at the subject side portion of the lens barrel 60. The inner yoke portion 42, which is a part of the yoke 40, can be disposed in a space generated by providing such a middle outer peripheral portion 65 (outer diameter step hε) in the lens barrel 60.

  FIG. 3 is an enlarged view showing a magnetic circuit example of the yoke 40 on the lower outer peripheral portion 64 and the middle outer peripheral portion 65 of the lens barrel 60. The magnetic circuit I shown in FIG. 3 is configured in a portion of the lens barrel 60 of the lens actuator 1 where the lower outer peripheral portion 64 and the middle outer peripheral portion 65 of the stepped cylindrical body 61 are extracted.

  According to the lens actuator 1, the one-sided single-pole magnetized magnet 50 is disposed in the yoke 40. The magnet arrangement of this specification is intended to reduce the thickness of the magnetic circuit structure by reducing the height of the magnet 50 in the optical axis direction. In addition, the inner yoke portion 42 which is a part of the yoke 40 is disposed in an excess space generated by slimming the holder for the lens barrel and providing the middle outer peripheral portion 65 (outer diameter step hε). In the magnetic circuit I, a driving coil 30 is disposed.

  In this example, the magnetic flux Φ emitted from the N pole of the magnet 50 is linked to the coil 30 to reach the inner yoke portion 42, passes through the yoke 40, and returns to the S pole from the outer yoke portion 41. A magnetic circuit I forming a path is formed.

  As described above, when the coil 30, the inner yoke portion 42, the magnet 50, and the like are arranged, the magnetic flux density (magnetic force) in the surplus space increases, and the same current as that applied to the conventional lens actuator is supplied to the lens actuator. When one coil 30 is energized (applied), a larger thrust F can be generated than in the conventional method.

  Further, since the closed magnetic path is formed by the inner yoke portion 42, the leakage magnetic flux to the outside can be reduced. In addition, since the single-sided single-pole magnetized magnet 50 is used, the reduction in magnetic force can be suppressed even if the height of the magnet 50 in the optical axis direction is set lower than in the single-sided two-pole magnetized specification. . As a result, it is housed in the same outer shape as the conventional type without the inner yoke portion, and it is possible to achieve high thrust and miniaturization at the same time.

  Next, a method for assembling the lens unit 100 will be described. 4-8 is process drawing which shows the assembly example (the 1-5). FIG. 9 is a flowchart showing an example of the lens focus adjustment.

  In this embodiment, the assembled lens body 70 is assembled in the lens barrel 60 that forms the stepped cylindrical body 61 as shown in FIG. 3, and the lens actuator 1 is assembled using the lens barrel 60 and then stored in the lens barrel 60. It is assumed that the assembled lens body 70 is driven with respect to the base 10 and the lens focus of the lens unit 100 is adjusted.

  Using these as assembling conditions, the lens actuator 1 is first assembled in step A1 of the flowchart shown in FIG. In this example, the lens barrel 60 forming the stepped cylindrical body 61 shown in FIG. 4A, the lenses 71 and 72 having the same diameter as shown in FIG. 4B, the diaphragm 74, the spacer 75 shown in FIG. 4C, and the difference shown in FIG. 4D. A lens 73 having a diameter is prepared. As the lens barrel 60, the stepped cylindrical body 61 described in FIG. The lens barrel 60 forms, for example, a stepped cylindrical body 61 having a lower outer peripheral portion 64 and a middle outer peripheral portion 65 by molding a resin containing carbon fiber. In this example, an opening 66 for storing a lens is formed in the stepped cylindrical body 61 during mold forming. In addition to the resin, a light metal, an aluminum die cast, or the like is used as the material for the lens barrel.

  When these parts are prepared, first, lenses 71 and 72 and a diaphragm portion 74 having the same diameter are incorporated and stored in the inner cylindrical portion 62 shown in FIG. 4A. In this example, the combined body is fitted into the inner cylindrical portion 62 in a state where the diaphragm portion 74 shown in FIG. 4B is sandwiched between the lens 71 and the lens 72. Thereafter, in the drawing, a spacer 75 shown in FIG. Thereafter, a lens 73 having a different diameter is fitted into the inner cylindrical portion 63 of the stepped cylindrical body 61.

  Next, the coil 30 shown in FIG. 5A is prepared, and the coil 30 is arranged and fixed on the lower outer peripheral portion 64 of the stepped cylindrical body 61. For example, the coil 30 having an outer diameter slightly narrower than the outer diameter of the lower outer peripheral portion 64 of the lens barrel 60 is created and attached to the lower outer peripheral edge 64 of the lens barrel 60 shown in FIG. 5B. The coil 30 is formed by winding a copper wire having a predetermined wire diameter into a cylindrical shape with the stepped cylindrical body 61 of the lens barrel 60 as a winding shaft portion, the number of turns being N, and the number of layers being M. Form.

  At this time, it winds so that a clearance gap may be produced between the lower outer peripheral part 64 of the lens-barrel 60, and the inner surface side of the coil 30. FIG. The clearance is for eliminating friction between the inner yoke portion 42 and the coil 30. The coil 30 wound here is firmly fixed to the lower outer peripheral portion 64 of the lens barrel 60 using an adhesive. For example, a urethane-based adhesive is used.

  Next, a yoke 40 shown in FIG. 6A and a magnet 50 shown in FIG. 6B are prepared. In this example, a yoke 40 and a magnet 50 having an outer peripheral portion having a round cylindrical shape and an inner peripheral portion having a cylindrical shape are prepared, and the yoke 40 and the magnet 50 are combined. For example, an SPC (cold rolled steel plate) having a predetermined thickness is processed, the outer peripheral portion is formed in a rounded cylindrical shape, and the inner peripheral portion is formed in a cylindrical shape. This cylindrical inner peripheral part forms the opening 43 of the yoke 40. The reason why the cylindrical shape is rounded is to accommodate it in the cylindrical casing formed by the cover member 80 and the base 10 shown in FIG.

  In this example, when the SPC is deployed, the portion that becomes the tip of the upper portion of the yoke (the portion that becomes the inside of the yoke 40) is arranged around the inside of the yoke 40 so that it can extend onto the middle outer peripheral portion 65 of the lens barrel 60. Bend it so that it folds in a U shape. Then, the yoke 40 is formed so that the inner yoke portion 42 faces the outer yoke portion 41. The yoke 40 may be formed by bending, pressing, drawing, welding, or the like.

  The SPC is subjected to surface treatment (trivalent chromate treatment) by zinc (Zn) plating. Electroless plating (EL / FeP− / OP3) is employed for the surface treatment. As the magnet 50, a flat cylindrical NdFeB (neodymium) sintered magnet, a ferrite magnet, an alnico magnet, or the like that is surface-treated by nickel (Ni) plating is used as a single-sided monopolar magnetic body. The magnet 50 is adhered to the inside of the yoke 40. For example, an adhesive is applied to the side surface of the magnet 50, and the magnet 50 is adhered and fixed to the inner peripheral portion of the yoke 40 via the adhesive.

  Next, the base 10 shown in FIG. 7C is prepared. In this example, a cylindrical base 10 having an upper part opened in the drawing and having a member storage portion 17 is prepared. For example, the base 10 is formed with a mold modeled on the base 10, and a base material is sealed in the mold to form the opening 16 and the component storage unit 17 in a cylindrical body. As the material of the base 10, resin, light metal (aluminum), aluminum die casting, or the like is used.

  When these members are prepared, the coil-fixed lens barrel 60 shown in FIG. 7B and the magnet-fixed yoke 40 shown in FIG. 7A are placed in the member storage portion 17 of the base 10 shown in FIG. 7C. Incorporate. At this time, it is combined so that the lens barrel 60 with the coil fixed can be covered with the assembly of the yoke 40 with the magnet fixed. In this example, the inner yoke portion 42 in which part or all of the edge portion is folded is disposed on the middle outer peripheral portion 65 of the stepped cylindrical body 61.

  Further, the inner yoke portion 42 disposed on the middle outer peripheral portion 65 of the stepped cylindrical body 61 and the magnet 50 disposed and fixed on the inner yoke portion 42 are movable with respect to the base 10 so as to sandwich the coil 30. A stepped cylindrical body 61 is incorporated. For example, the coil 30 is inserted into (inserted into) the gap between the inner yoke portion 42 and the magnet 50 that are folded back in a U-shape. In this combined state, the coil-fixed lens barrel 60 and the magnet-fixed yoke 40 are arranged in the base 10 shown in FIG. 7C. Then, the yoke 40 is fixed to the base 10. Thereby, the lens actuator 1 (intermediate assembly part) as shown in FIG. 8B is completed.

  Thereafter, the cover member 80 shown in FIG. 8A is prepared and assembled so as to cover the upper part of the intermediate assembly part. For the cover member 80, for example, an aluminum plate is pressed and punched to form an opening 81 at the center and finished into a cylindrical shape. Then, the lens actuator 1 shown in FIG. 8B and the cover member 80 shown in FIG. 8A are joined.

  The cover member 80 and the base 10 are coupled by a screw member or the like (not shown). The coupling is not limited to the screw member, and the cover member 80 and the base 10 may be bonded and fixed with an adhesive. As a result, the lens unit 100 as shown in FIG. 1 is assembled, in which the lens barrel 60 with the coil on the movable part side is movable with respect to the base 10 on the fixed part side including the yoke 40 and the magnet 50. To complete.

  Thereafter, the process proceeds to step A2 shown in FIG. 9, and the lens unit 100 is mounted on the camera. For example, an imaging device is mounted on a housing portion of a camera (not shown), the base 10 of the lens unit 100 is attached to the housing portion using an adhesive or the like, and the housing portion and the base 10 are fastened to each other (fixing step).

  Then, the lens focus is adjusted in step A3 shown in FIG. In this example, the coil 30 of the lens unit 100 is energized. For example, when adjusting the focus of the assembled lens body 70 with respect to the image sensor mounted on the camera, a step is formed at a position where the optical characteristics are good while confirming an image captured by the image sensor through the assembled lens body 70 on a monitor or the like. The lens barrel 60 forming the cylindrical shape 61 is finely adjusted (adjustment process). Thereafter, the process proceeds to step A4 where the lens barrel 60 is fixed. For example, the adjusted lens barrel 60 is fixed to the base 10 with an adhesive. Thereby, the lens focus adjustment of the lens unit 100 is completed.

  As described above, according to the lens actuator 1 as the embodiment, when the lenses 71, 72, 73 and the diaphragm portion 74 housed in the lens barrel 60 are driven with respect to the base 10, the stepped cylindrical shape of the lens barrel 60. The inner yoke portion 42 disposed on the middle outer peripheral portion 65 of the body 61 forms a closed magnetic path including the magnet 50 and the coil 30.

  In the above-described example, the lens actuator 1 uses a difference in the outer diameter of the lens in the combined lens barrel 60 to provide a step in the outer shape of the lens barrel, and the intermediate outer peripheral portion of the step cylindrical body 61 generated by the step. A part of the magnetic circuit I is overlapped on 65. Therefore, the magnetic flux generated by the magnet 50 can be sufficiently linked to the coil 30.

  Further, according to the assembling method of the lens actuator 1, the inner yoke portion 42 disposed at the middle outer peripheral portion 65 of the stepped cylindrical body 61 constituting the lens barrel 60, and the magnet 50 disposed and fixed on the inner yoke portion 42, Thus, the lens barrel 60 is incorporated so as to be movable with respect to the base 10 so as to sandwich the coil 30. As a result, the holder for attaching the lens barrel as in the conventional method and the screw portion thereof can be omitted, and the integrated structure of the holder can be adopted. Therefore, it is possible to further reduce the size of the lens actuator 1 in the future. Become.

  This makes it possible to reduce the thickness and power consumption of digital cameras using a small lens actuator 1 having an autofocus function, camera modules such as video cameras and mobile phones.

  The present invention is extremely suitable when applied to a lens unit for a camera module such as a digital camera, a video camera, or a mobile phone.

1 is a partially fragmented perspective view showing a configuration example of a lens unit 100 as an embodiment according to the present invention. 2 is a cross-sectional view supplementing a configuration example of a lens unit 100. FIG. FIG. 6 is an enlarged view showing an example of a magnetic circuit of the yoke 40 on the lower outer periphery and the middle outer periphery 65 of the lens barrel 60. FIG. 5 is a process diagram showing an assembly example (No. 1) of the lens unit 100; FIG. 6 is a process diagram illustrating an assembly example (No. 2) of the lens unit 100. FIG. 10 is a process diagram illustrating an assembly example (No. 3) of the lens unit 100; FIG. 6 is a process diagram illustrating an assembly example (No. 4) of the lens unit 100; FIG. 10 is a process diagram illustrating an assembly example (No. 5) of the lens unit 100; 4 is a flowchart illustrating an example of lens focus adjustment of the lens unit 100. It is sectional drawing which shows the structural example of the lens unit 200 which concerns on a prior art example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Lens actuator (lens drive device) 10 ... Base (base), 61 ... Stepped cylindrical body, 30 ... Coil, 40 ... Yoke (support member), 41 ... Outer yoke part, 42 ... Inner yoke part, 50 ... Magnet (magnetic body), 60 ... Tube, 62,63 ... Inner cylindrical part, 64 ... Lower outer peripheral part, 65 ... periphery of middle stage, 70 ... assembled lens body, 71, 72, 73 ... lens, 74 ... diaphragm, 80 ... cover member, 100 ... lens unit

Claims (3)

A lens driving device for driving a lens housed in a lens barrel with respect to a base;
A lens barrel configured to be movable with respect to the base in a stepped cylindrical body that accommodates lenses of different diameters;
A coil disposed and fixed on the outer periphery of the stepped cylindrical body;
A support member disposed on the outer periphery of the coil and fixed to the base;
A magnetic body disposed and fixed on the inner periphery of the support member,
A part or all of the edge of the support member is folded and disposed on the outer periphery of the stepped cylindrical body,
A lens driving device in which the lens barrel is incorporated so that the coil is sandwiched between the support member disposed on the outer peripheral portion of the stepped cylindrical body and the magnetic body disposed and fixed on the support member. . The support member is
The portion arranged on the outer peripheral portion of the coil and fixed to the base constitutes an outer yoke portion,
2. The lens driving device according to claim 1, wherein a part of the edge part is folded back and a part disposed on an outer peripheral part of the stepped cylindrical body constitutes an inner yoke part. A method for assembling a lens driving device for driving a lens housed in a lens barrel with respect to a base,
Storing a lens having a different diameter in a stepped cylindrical body for a lens barrel;
Arranging and fixing a coil on the outer periphery of the stepped cylindrical body;
Arranging and fixing a magnetic body on the inner peripheral portion, folding back part or all of the edge portion and arranging the support member on the outer peripheral portion of the stepped cylindrical body;
The stepped cylindrical body is movable with respect to the base so as to sandwich the coil between the support member disposed on the outer peripheral portion of the stepped tubular body and the magnetic body disposed and fixed on the support member. The process of incorporating
A method of assembling the lens driving device, comprising: fixing a support member to the base.

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