JP2006050693A - Actuator for auto-focusing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator for auto-focusing capable of supplying power to a coil without mediating a spring. <P>SOLUTION: The actuator comprises a holder 10, a coil 20 provided at the flange section 12 of the holder 10, a yoke 30 arranged to contain the coil 20, a pair of leaf springs 60 provided above and below the holder 20 to support the holder 20 and a plurality of permanent magnets arranged on the yoke 30 to oppose the coil 20 while spaced apart therefrom displaceably in the direction of an optical axis while positioning in the radial direction, and a sheet-like electrode 90 provided on the lower surface of a lower leaf spring 60L and being connected with the lead-out portion 21 of the coil 20 wherein power can be supplied to the coil 20 through the sheet-like electrode 90. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an autofocus actuator, and more particularly to an autofocus actuator that can be used in a small electronic device with a camera such as a digital camera or a mobile phone.

  In a digital camera or the like, an actuator that can move a lens in the optical axis direction by the interaction between a magnetic field generated by a current flowing in a coil and a magnetic field generated by a magnet is used for the purpose of autofocus and zoom. In recent years, cameras mounted on mobile phones are also required to have an autofocus function as the number of pixels of the image sensor becomes 1 million pixels or more.

  As a conventional autofocus actuator, one disclosed in Patent Document 1 is known. The actuator includes a front lens, a front support frame that supports the front lens, a front coil attached to the front support frame, a front spring attached to the front support frame, a rear lens, and a rear that supports the rear lens. A support frame, a rear coil attached to the rear support frame, a rear spring attached to the rear support frame, a magnet, a magnet support, and a yoke, and the front coil has an outer gap between the magnet and the yoke. The rear coil is disposed in the inner gap between the magnet and the yoke, and by applying a current to the front coil, the front lens is moved to a position that balances the elastic force of the front spring, and the current is applied to the rear coil. By applying this, the rear lens is moved to a position that balances the elastic force of the rear spring.

JP2003-295033

  The conventional actuator has a structure in which power is supplied to the coil via a front spring and a rear spring. Therefore, it is necessary to provide the coil portions and the power source electrode portions on the front spring and the rear spring, respectively. Since bending is performed for this purpose, there is a problem in that the yield of the spring is lowered.

  In addition, since a coil or a conductive wire is directly soldered to the spring itself to establish conduction, there is a problem that the structure requires insulation and the number of parts increases.

  Furthermore, since the front spring and the rear spring have different shapes, there is a problem that the springs cannot be shared and the cost of parts increases.

  Furthermore, the front spring and the rear spring are manufactured in a shape in which two springs are connected in a circular shape, and are cut after being attached, which causes a problem that the assembly process becomes complicated.

  The present invention has been made in view of these problems, and an object of the present invention is to provide an autofocus actuator that can supply power to a coil without using a spring such as the front spring and the rear spring of the conventional example. It is to provide.

In order to achieve the above object, an autofocus actuator according to the present invention includes a holder having a cylindrical portion to which a lens is attached at one end and a flange provided on the outer periphery of the other end of the cylindrical portion;
A coil fixed to the flange portion of the holder so as to be positioned around the cylindrical portion;
An inner cylinder part forming an insertion hole through which the cylindrical part of the holder is inserted; and an outer cylinder part provided at a predetermined interval outside the inner cylinder part, the inner cylinder part and the outer cylinder part A yoke that is integrally connected to the end of the holder opposite to the flange portion, and is configured to accommodate the coil in the space of the predetermined interval;
A permanent magnet arranged to face the magnet mounting surface on the inner peripheral surface of the outer cylindrical portion of the yoke at a distance from the coil;
A pair of leaf springs provided on both sides in the optical axis direction of the cylindrical portion of the holder, and supported so as to be displaceable in the optical axis direction with the holder positioned in the radial direction;
Provided on the outside of each of the pair of leaf springs, and sandwiching the leaf springs between both end surfaces in the optical axis direction of the yoke, and at least opening portions corresponding to the lenses attached to the holder. An autofocus actuator comprising: a pair of support frames having a lens attached to the holder so that the position of the lens attached to the holder can be adjusted in an optical axis direction by energizing the coil;
A sheet-like electrode for supplying electric power to the coil is provided on the support frame side surface of the leaf spring on the flange side of the holder.

  According to the autofocus actuator of the present invention having the above-described configuration, the coil portion is energized using the sheet-like electrode provided independently of the leaf spring. For example, it is not necessary to consider the insulation of the leaf spring. Further, the pair of leaf springs can be made the same shape, which can reduce the cost and can be easily assembled.

In the autofocus actuator of the present invention, it is preferable that the sheet-like electrode has a ring-shaped portion formed in a substantially ring shape and an extending portion extending radially outward from the ring-shaped portion.
Thereby, positioning of a leaf | plate spring and a sheet-like electrode can be performed easily.

In the autofocus actuator of the present invention, the coil is wound so that the leading portions on both sides of the winding are located on the flange portion side of the holder, and the sheet-like electrode has its support frame A terminal portion made of a conductor is provided on the side surface along the ring-shaped portion and the extending portion, and lead portions on both sides of the coil winding are connected to the terminal portion of the sheet-like electrode. It is preferable.
Thereby, a sheet-like electrode and a coil can be connected easily.

In the autofocus actuator of the present invention, the sheet-like electrode is provided with an adhesive layer for adhering to the leaf spring at least on the ring-like portion on the surface opposite to the support frame side. It is preferable.
Thereby, it can be easily bonded to the leaf spring.

In the autofocus actuator of the present invention, it is preferable that the extending portion extends to the outside of the support frame through an insertion hole provided in the support frame on the flange side.
Thereby, a sheet-like electrode and an external power supply source can be connected easily.

Further, an autofocus actuator according to another aspect of the present invention includes a holder having a cylindrical portion with a lens attached to one end thereof,
A coil arranged and fixed to the holder around the cylindrical portion of the holder;
A pair of leaf springs provided on both sides in the optical axis direction of the cylindrical portion of the holder, and supported so as to be displaceable in the optical axis direction with the holder positioned in the radial direction;
A permanent magnet facing the coil is provided, and by energizing the coil, the position of the lens attached to the holder in the optical axis direction can be adjusted by the interaction between the permanent magnet and the magnetic field generated in the coil. A yoke for
It has a sheet-like electrode for supplying electric power to the coil provided on the opposite side to the holder of the leaf spring.

  According to the autofocus actuator of the present invention having the above-described configuration, the coil portion is energized using the sheet-like electrode provided independently of the leaf spring. For example, it is not necessary to consider the insulation of the leaf spring. Further, the pair of leaf springs can be made the same shape, which can reduce the cost and can be easily assembled.

  The above-described and other configurations, operations, and effects of the present invention will become more apparent from the following description of preferred embodiments with reference to the drawings.

  Hereinafter, the autofocus actuator of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

  FIG. 1 is a perspective view showing an appearance of an embodiment of an autofocus actuator according to the present invention. FIG. 2 is an exploded perspective view of the autofocus actuator shown in FIG. FIG. 3 is a schematic cross-sectional view of the autofocus actuator shown in FIG.

  As shown in FIGS. 1, 2, and 3, the autofocus actuator according to the present embodiment is provided on the outer periphery of the cylindrical portion 11 to which the lens assembly 100 is attached at one end and the other end of the cylindrical portion 11. A holder 10 having a flange portion 12 formed; a coil 20 provided in the flange portion 12 of the holder 10 with a space around the tubular portion 11; and an insertion hole through which the tubular portion 11 of the holder 10 is inserted. 35, an outer cylinder part 32 provided at a predetermined interval on the outer side of the inner cylinder part 31, and the inner cylinder part 31 and the outer cylinder part 32 on the opposite side to the flange part 12 of the holder 10. A circular yoke 30 having a connecting portion 34 whose end portions are integrally connected, and configured to house the coil 20 in a predetermined space between the inner cylindrical portion 31 and the outer cylindrical portion 32; The outer cylindrical portion 32 of the circular yoke 30 A plurality of permanent magnets 40 arranged so as to face the magnet mounting surface 33 on the circumferential surface at a distance from each other; abutting against a surface of the permanent magnet 40 opposite to the connecting portion 34 of the circular yoke 30 In this state, the magnetic member 50 arranged to connect the plurality of permanent magnets 40; provided on both sides of the cylindrical portion 11 of the holder 10 in the optical axis direction, and the optical axis in a state where the holder 10 is positioned in the radial direction A pair of leaf springs 60 comprising an upper leaf spring 60 </ b> U and a lower leaf spring 60 </ b> L that are displaceably supported in the direction; and a stopper 70 that fits the holder 10 so as to sandwich the upper leaf spring 60 </ b> U with the holder 10. A lens set provided on the outer side in the optical axis direction of each of the pair of leaf springs 60, holding the leaf spring 60 between both end surfaces in the optical axis direction of the yoke 30, and attached to at least the holder 10. A cover 80 and a base 85 forming a pair of support frames having openings 80a and 85a at portions corresponding to the body 100; provided between the lower leaf spring 60L and the base 85 to supply power to the coil 20. Sheet-like electrode 90;

  Hereinafter, details of each component will be described. In the present specification, the terms “upper” and “lower” are used as appropriate. In the description of each member, the direction of the arrow shown in FIG. 2 is the upward direction, and the opposite direction of the arrow is the downward direction.

  The holder 10 is a molded product made of synthetic resin, and is integrally provided on the outer periphery of a cylindrical cylindrical portion 11 to which the lens assembly 100 is attached at one end (upper end) and the other end (lower end) of the cylindrical portion 11. And a circular flange portion 12 formed. As shown in FIG. 3, the cylindrical portion 11 of the holder 10 is hollow, and the upper inner peripheral surface thereof is screwed with a male screw portion formed on the outer periphery of the lens assembly 100. A female screw portion is formed. Further, a stepped portion 12a for bonding the coil 20 in a positioned state is provided on the peripheral portion of the upper surface of the flange portion 12 (the surface on the cylindrical portion 11 side) (see FIG. 3). Further, on the lower surface of the flange portion 12, a ring-shaped convex portion (step portion) 15 for positioning and mounting the lower leaf spring 60 is formed concentrically. On the convex portion 15, three thin protrusions 13 extending in the optical axis direction are formed integrally with the convex portion 15 at equal intervals.

  As described above, the coil 20 is provided on the step portion 12 a on the upper surface of the flange portion 12 of the holder 10 so as to be spaced from the periphery of the cylindrical portion 11 of the holder 10. In the present embodiment, the coil 20 is formed by coating the surface of a copper wire with different numbers of turns in which a layer of 10 turns and a layer of 9 turns are alternately stacked, and the cross section is an empty space having a circular shape. It is a core coil. Further, the coil 20 is wound so that the leading portions 21 at both ends of the winding are positioned on the flange portion 12 side. Such an air core coil is fixed to the step on the upper surface of the flange portion 12 of the holder 10 with an adhesive. In the present invention, the coil 20 is not limited to the air core coil as described above, and may be a coil that is directly wound around the cylindrical portion 11.

  As shown in FIG. 4, the yoke 30 includes a cylindrical inner cylinder portion 31 having an insertion hole 35 through which the cylindrical portion 11 of the holder 10 is inserted, and a predetermined interval on the outer side of the inner cylinder portion 31. A cylindrical outer tube portion 32 provided; and an inner tube portion 31 and a connecting portion 34 integrally connected to the end of the outer tube portion 32 opposite to the flange portion 12 of the holder 10. The coil 20 is accommodated in a space of a predetermined interval between the outer cylinder portion 31 and the outer cylinder portion 32.

  The yoke 30 is made of a magnetic material, for example, an iron surface nickel-plated. In order to insert the cylindrical portion 11 of the holder 10 into the insertion hole 35 of the inner cylindrical portion 31 in a state where the cylindrical portion 11 is movable in the optical axis direction, the diameter of the insertion hole 35 of the inner cylindrical portion 31 is the cylindrical portion of the holder 10. 11 is larger than the diameter of the outer peripheral surface of the holder 10 and smaller than the diameter of the peripheral edge of the flange portion 12 of the holder 10.

  Further, as shown in FIGS. 2 to 4, the height in the optical axis direction of the inner cylinder portion 31 with respect to the connecting portion 34 is formed to be lower than the height in the optical axis direction of the outer cylinder portion 32. .

  A plurality (four pieces) of permanent magnets 40 are arranged on the magnet mounting surface 33 on the inner peripheral surface of the outer cylindrical portion 32 of the circular yoke 30 so as to face the coil 20 with a space therebetween. Each of these permanent magnets 40 is formed of a permanent magnet that is curved in an arc shape of approximately 90 degrees along the shape of the circular magnet mounting surface 33. These permanent magnets 40 are made of neodymium magnets, and are magnetized so that, for example, the curved surface on the side contacting the magnet mounting surface 33 is an S pole, and the curved surface substantially opposite to the curved surface is an N pole. By attaching these arcuately curved permanent magnets 40 to the circular yoke 30, the outer peripheral surface of the inner cylinder part 31 of the yoke 30 becomes the S pole, and the arcuately curved permanent magnets 40 to the inner cylinder part 31. A magnetic field toward is formed. When the coil 20 located in the space between the permanent magnet 40 and the outer peripheral surface of the inner cylinder portion is energized by this magnetic field, the coil is caused to interact with the magnetic field and the magnetic field generated by the current flowing through the coil in the direction of the optical axis. Thus, the holder 10 can be moved in the optical axis direction. Note that the number of permanent magnets is not limited to four pieces, and a plurality of other magnets may be used, or one C-shaped permanent magnet may be used.

  By the way, in the circular yoke 30 as described above, between the adjacent permanent magnets 40 at the open portion opposite to the connecting portion 34 of the circular yoke 30 as indicated by the arrow shown in FIG. Magnetic flux leaks downward. By providing the prevention means for preventing the leakage of the magnetic flux, the driving force of the holder 10 can be increased.

  In the present invention, as a means for preventing the leakage of magnetic flux, a plurality of permanent magnets 40 are connected in contact with the lower end surface of the permanent magnet 40 (the surface opposite to the connecting portion 34 of the circular yoke 30). A magnetic member 50 is disposed on the surface. By providing the magnetic member 50, as shown in FIG. 6, the magnetic flux leaking downward is reduced, and the magnetic flux from the permanent magnet 40 toward the inner cylindrical portion 31 of the circular yoke 30 is increased. As shown in FIG. 7, in the present embodiment, a circular ring-shaped magnetic member 50 is adsorbed to a permanent magnet 40 and then fixed thereto with an adhesive. As shown in FIG. 6, the width of the ring-shaped magnetic member 50 is equal to the radial thickness of the permanent magnet 40 curved in an arc shape. Thereby, arrangement | positioning of the coil 20 accommodated in the yoke 30 is not prevented. Further, the surface on the open side of the magnetic member 50 having a ring shape is positioned below the end surface of the outer cylinder portion 32 of the yoke 30 in the attached state.

  The said magnetic material is formed from the magnetic material which consists of iron, nickel, cobalt, and those alloys, and the cold rolled steel plate is used in this embodiment.

  As shown in FIG. 8, each leaf spring (upper leaf spring 60U, lower leaf spring 60L) is made of a thin metal plate and has an inner ring portion 61 and an outer ring portion provided at a predetermined interval from the inner ring portion 61. The ring portion 62 is formed in a gimbal spring shape having a plurality of connecting portions 63 that connect the inner ring portion 61 and the outer ring portion 62. When a load is applied to the inner ring part 61 in a state where the outer ring part 62 is fixed, the connecting part 63 is elastically deformed, and the holder 10 to which the inner ring part 61 is bonded is positioned in the radial direction. It is supported so that it can be displaced in the optical axis direction.

  On the upper surface of the holder 10, a step portion 16 is formed for positioning the upper leaf spring 60U during assembly. The cross-sectional shape of the step portion 16 has substantially the same shape as the inner periphery of the inner ring portion 61. The inner ring portion 61 of the upper leaf spring 60U is placed on the upper surface of the holder 10 in a state where the upper ring spring 60U is fitted to the stepped portion 16, and the stopper 70 is further mounted thereon. It is bonded to the holder 10 while being sandwiched between the lower surface of the stopper. Further, the outer ring portion 62 is bonded to the cover 80 and the yoke 30 while being sandwiched between the lower surface of the cover 80 and the upper surface of the connecting portion 34 of the yoke 30.

  As described above, the flange-side end portion of the holder 10, that is, the lower surface of the flange portion is also formed with the step portion 15 for positioning the lower leaf spring 60 </ b> L during assembly, and the cross-sectional shape thereof is the inner ring portion. The inner ring 61 has the same shape as the inner periphery, and is bonded in a state where the inner ring portion 61 is positioned. The outer ring portion 62 is bonded to the base 85 and the yoke 30 while being sandwiched between the end surface of the outer cylindrical portion 32 of the circular yoke 30 and the upper surface of the base 85.

  As shown in FIG. 9, a sheet-like electrode 90 provided to supply power to the coil 20 between the lower leaf spring 60L and the base 85 is a ring formed in a substantially circular ring shape made of a polyimide sheet material. And a projecting portion 92 extending radially outward from the ring-shaped portion 91.

  Two terminal portions 93 made of copper are provided on one surface of the sheet-like electrode 90 from the extending portion 92 to the ring-shaped portion 91. In the ring-shaped portion 91, a dummy terminal portion 95 for soldering a dummy wire 23 described later is provided between the tips of the two terminal portions 93.

  Further, on the other surface of the sheet-like electrode 90, an adhesive layer (not shown) for bonding the sheet-like electrode 90 to the lower surface of the outer ring portion 62 of the lower leaf spring 60L is extended with the ring-shaped portion 91. It is provided in the vicinity of the connection portion of the portion 92 with the ring-shaped portion and in the vicinity of the distal end portion of the extension portion 92.

  Further, the extending portion 92 extends to the outside of the support frame through an insertion hole 88 of the base 85 described later and is connected to a sensor substrate (not shown). In order to insert the extension 92 into the insertion hole 88, it is necessary to bend the extension 92 approximately 90 degrees with respect to the ring-shaped portion 91. In order to prevent the terminal part 93 from being damaged by this bending, a cover film 94 made of polyimide is provided on the terminal part 93.

  Electric power can be supplied to the coil 20 by soldering the leading end of the lead portion 21 of the coil 20 to the terminal portion 93 provided on the ring portion 91 of the sheet-like electrode 90. However, undesired contact between the drawer portion 21 and other members caused by the displacement of the holder 10 and stress concentration at the soldered tip end occur. Therefore, as shown in FIG. 10, the drawing portions 21 on both sides of the winding of the coil 20 are wound around the three thin protrusions 13 provided on the step portion 15 on the lower surface of the flange portion 12 of the holder 10 and then drawn out. The tip of the portion 21 is soldered to the terminal portion 93 of the sheet electrode 90.

  These projections 13 have a cylindrical shape having a height that does not contact the upper surface of the base plate 86 of the base, which will be described later, in the assembled state.

  The lead portion 21 extends from the coil 20 to the lower surface side of the flange portion 12 through a recess 14 (see FIG. 12) provided at the edge portion of the flange portion 12, and is wound around the protrusion 13.

  The lead-out portion 21 between the protrusion 13 and the soldering portion 22 is attached in a slack state so that no tensile stress is generated even when the holder 10 is displaced.

  Furthermore, in the present embodiment, as shown in FIG. 11, a portion where the lead portion 21 is wound around the protrusion 13 of the holder 10 and soldering in which the tip of the lead portion 21 is soldered to the terminal portion 93 of the sheet electrode 90. The stress relaxation agent 24 is provided so as to wrap the portion 22, and stress can be prevented from concentrating on a part of the drawer portion 21.

  Further, as shown in FIG. 12, three protrusions 13 are provided on the lower surface of the flange portion 12 at substantially equal intervals. Each of the inner ring portions 61 of the lower leaf spring 60 </ b> L bonded to the lower surface of the flange portion 12. Is inserted at the position of a substantially semicircular recess 66 (see FIG. 8) at the inner edge.

  The lead portion 21 of the coil 20 is wound around two of the three protrusions 13. The remaining one is provided with balance holding means.

  This balance holding means includes a dummy wire 23 using the same wire as the winding of the coil 20. One end of the dummy wire 23 is wound around the protrusion 13, and the other end is soldered to the dummy terminal portion 95 of the sheet-like electrode 90. Thereby, the balance of the holder 10 can be maintained, and it becomes possible to operate in a stable posture.

  A stress relieving agent 24 is provided so as to wrap the portion around which the dummy wire 23 is wound around the protrusion 13 and the soldered portion of the dummy wire 23, and prevents the stress from concentrating on a part of the dummy wire 23 and the holder. Ten balances can be maintained.

  In the present invention, instead of using the sheet electrode 90 as described above, for example, the lower surface of the outer ring portion 62 of the lower leaf spring 60L that does not displace with the displacement of the holder 10 (opposite to the holder 10). A terminal portion connected to the power source portion may be formed on a part of the side surface) via an insulating material, and the end portion of the lead portion 21 of the coil 20 may be connected thereto.

  As shown in FIG. 13, the stopper 70 is made of a synthetic resin molded into a ring shape, and the inner peripheral edge is the upper surface portion of the holder 10 with the inner ring portion 61 of the upper leaf spring 60 </ b> U sandwiched between the holder 10. The step 16 is fitted and bonded.

  A part of the edge of the three openings 71 is positioned so as to coincide with the shape of the substantially semicircular recess 65 (see FIG. 8) at the outer edge of the inner ring part 61 of the upper leaf spring 60U. Assembled. Therefore, the clearance between the cylindrical portion 11 of the holder 10 and the inner cylindrical portion 31 of the yoke 30 can be confirmed through the opening 71 and the substantially semicircular concave portion 65 from the upper surface side.

  As shown in FIG. 2, the cover 80 assembled so as to sandwich a part of the outer ring portion 62 of the upper leaf spring 60U with the connecting portion 34 of the yoke 30 has a substantially rectangular upper shape having an opening 80a. The plate portion 81 and the column portion 82 provided at the corner portion of the upper plate portion 81 and perpendicular to the upper plate portion 81 and downward are provided.

  The base 85 assembled so as to sandwich a part of the outer ring portion 62 of the lower leaf spring 60L between the end surface of the outer cylinder portion 32 of the yoke 30 includes a substantially rectangular bottom plate portion 86 having an opening 85a and the base plate portion 86. At the corners of the bottom plate portion 86, there are column portions 87 provided vertically and upward with respect to the bottom plate portion 86.

  The column portion 82 of the cover 80 and the column portion 87 of the base 85 are respectively fitted to each other, and can be bonded in an easily positioned state during assembly.

  As shown in FIG. 14, three substantially triangular convex portions 201 are provided on the inner edge of the opening 80 a of the cover 80, and three substantially triangular concave portions 72 provided on the outer edge of the stopper 70. Each is arranged so as to be fitted with a gap. Thereby, in order to limit the rotation of the holder 10 bonded to the stopper 70 in the circumferential direction, plastic deformation of the connecting portion 63 of the leaf spring 60, peeling of the bonding surface between the members, and breaking of the drawing portion 21 of the coil 20 are performed. The lens assembly 100 can be easily screwed into the holder 10 without causing problems such as.

  Further, a protrusion 202 protruding radially inward from the opening 80a is provided above the outer edge of the stopper 70. Even if a large force is applied to the holder 10 due to an impact or the like, the protrusion 202 is stopped by the stopper 70. 70, the displacement of the holder 10 is limited, plastic deformation of the connecting portion 63 of the leaf spring 60 supporting the holder 10, peeling of the adhesive surface between members, breakage of the drawing portion 21 of the coil 20, etc. Can be prevented.

  As shown in FIG. 2, the bottom plate portion 86 of the base 85 is provided with an insertion hole 88 through which the extension portion 92 of the sheet-like electrode 90 is inserted during assembly.

  Further, three protrusions 89 are provided at almost equal intervals in the vicinity of the opening 85a of the bottom plate portion 86 of the base 85 (see FIG. 3), and in the assembled state, the tip is on the lower surface of the flange portion 12 of the holder 10. It contacts the connecting portion 63 of the bonded lower leaf spring 60L. Since the height of the protrusion 89 is longer than the distance from the upper surface of the bottom plate portion 86 of the base 85 to the lower leaf spring 60L, the holder 10 is displaced upward, and the supporting leaf springs 60 have a downward elastic force. The holder 10 is always in a back tension state.

  Further, the bottom plate portion 86 of the base is provided with three circular openings 86a at almost equal intervals, and the state of the soldered portion 22 on the sheet-like electrode 90 can be inspected through these openings.

The assembly procedure of the autofocus actuator of the present invention will be described below.
[1] The coil 20 is fixed to the step 12a on the upper surface of the flange portion 12 of the holder 10 with an adhesive.

[2] Next, the four permanent magnets 40 are positioned at predetermined positions on the magnet mounting surface 33 on the inner peripheral surface of the outer cylindrical portion 32 of the yoke 30, and then fixed with an adhesive. In this state, a magnet spacer is attracted to the lower end surfaces of these permanent magnets 40 and fixed with an adhesive.

[3] Next, the holder 10 to which the coil 20 is fixed and the yoke 30 to which the above magnet spacer is attached are assembled. At this time, the cylindrical portion 11 of the holder 10 is inserted into the insertion hole 35 of the inner cylindrical portion 31 of the yoke 30, and the coil 20 is formed in a space between the outer peripheral surface of the inner cylindrical portion 31 of the yoke 30 and the permanent magnet 40. Assemble both so that they are stored.

[4] In the state of [3], the inner ring portions 61 of the respective leaf springs 60 are fitted to the upper and lower step portions 15 and 16 of the holder 10 and fixed with an adhesive.

[5] A stopper that fits with the step portion 16 in a state where the inner ring portion 61 of the upper leaf spring 60 is sandwiched between the upper surface of the upper leaf spring 60U bonded in [4] and the upper surface of the cylindrical portion 11. 70 is fixed with an adhesive.

[6] The ring-shaped portion 91 of the sheet-like electrode 90 is bonded to the outer ring portion 62 of the lower leaf spring 60L bonded in [4] via an adhesive layer.

[7] After winding the lead portion 21 and the dummy wire 23 of the coil 20 around the protrusion 13 of the holder 10, the tips are soldered to the terminal portion 93 and the dummy terminal portion 95 of the sheet-like electrode bonded in [6]. Is done. Further, a stress relaxation agent is applied to the portion wound around the protrusion 13 and the soldered portion.

[8] The cover 80 and the base 85 are attached to the parts assembled up to [7] so that the outer ring portion 62 of each leaf spring 60 is clamped between the yoke 30 and the yoke 30 and the cover 80. The outer ring part 62 of the side leaf spring is bonded to the lower end surface of the outer cylinder part 32 of the yoke 30 and the base 85, respectively. At this time, the extending portion 92 of the sheet electrode 90 is extended to the outside through the insertion hole 88 of the base.

[9] The lens assembly 100 is screwed into the screw portion of the holder 10 which is a part of the parts assembled up to [8].

The operation of the autofocus actuator of the above embodiment will be described below.
In FIG. 3, the direction of the magnetic field is from the permanent magnet to the inner cylinder portion 31 of the yoke 30. When the coil 20 is viewed from above with the holder 10 in the initial position, that is, counterclockwise, that is, in the cross-sectional view of FIG. When current flows from the back of the drawing in the front direction, an upward electromagnetic force is generated. The holder 10 is displaced until the electromagnetic force and the elastic force of the leaf spring 60 that changes according to the displacement of the holder 10 are balanced. Since the electromagnetic force is controlled by the amount of current flowing through the coil 20, the holder 10, that is, the lens assembly 100 can be displaced to an arbitrary position. Position information of the lens assembly 100 obtained from the amount of current flowing in the coil 20 of the autofocus actuator 1 of the present invention and an image detected by a detection element (not shown) located below the autofocus actuator 1. By performing high-speed calculation of information with a calculation unit having a predetermined autofocus algorithm and controlling the current flowing through the coil 20 based on the result, autofocus can be performed.

  According to the autofocus actuator according to the preferred embodiment of the present invention described above, the coil is energized using the sheet-like electrode provided independently of the leaf spring. There is no need to fold the part, and there is no need to consider the insulation of the leaf spring. Furthermore, the pair of leaf springs can be made common as leaf springs of the same shape, which can reduce costs and can be easily assembled.

  The autofocus actuator according to the present invention is not limited to the above embodiment, and various modifications and improvements can be made. Hereinafter, typical improvements will be described.

  For example, in the above embodiment, the yoke has a circular shape, and the permanent magnet also uses an arc-shaped magnet. However, such an arc-shaped magnet is expensive. There is a problem that a special jig is required for positioning and the manufacturing process is complicated.

  A rectangular parallelepiped, that is, a flat permanent magnet can be used, and as an improved example of a yoke that can easily position and assemble the permanent magnet, as shown in FIG. There is.

  As shown in FIG. 15, four magnet mounting surfaces 303 are provided on the inner peripheral surface of the outer cylindrical portion 302, and the substantially flat permanent magnet 41 that can be easily manufactured is connected to the magnet mounting surface. 303 can be attached in a magnetically attached state.

  Further, as shown in FIG. 15, concave portions 304 that are recessed inward are formed at the four corners of the outer cylindrical portion 302. Since the distance between the inner surfaces of the two recessed portions 304 on both sides of one magnet mounting surface 303 is substantially equal to the width of the substantially flat plate-like permanent magnet 41, the inner surface of the recessed portion 304 is a substantially flat plate-shaped permanent magnet. By abutting on the side surface of 41, the substantially flat permanent magnet 41 can be easily positioned.

  The substantially flat permanent magnet 41 is magnetized so that, for example, the side surface in contact with the magnet mounting surface 303 is an S pole and the surface substantially opposite to the side surface is an N pole. By attaching the permanent magnet 41 to the substantially square yoke 30, the outer peripheral surface of the inner cylindrical portion 301 of the circular yoke 300 becomes an S pole, and a magnetic field from the substantially flat permanent magnet 41 toward the inner cylindrical portion 301 is formed. Is done.

  Further, in this improved example, the inner cylindrical portion 301 of the substantially square yoke 300 is also formed in a substantially square cross section, and the coil accommodated at a predetermined interval from the inner cylindrical portion 301 and the substantially flat permanent magnet 41 is also substantially omitted. By using a coil wound in a square shape, the direction of the current flowing through the coil and the direction of the magnetic field formed inside the substantially square yoke 300 are substantially perpendicular, so that a sufficient driving force can be obtained. Can do.

  When such a substantially square-shaped yoke 300 is used, as shown in FIG. 17, each of the outer edges of the four corners has a substantially rectangular ring shape in which concave portions that are recessed inward are formed. A magnetic member 51 is used. The width of the portion other than the recessed portion is equal to the thickness of the substantially flat permanent magnet 41.

  Further, as an improved example of a yoke in which a flat permanent magnet can be used and the magnets can be easily positioned and assembled, as shown in FIG. 16, a yoke 310 having a hexagonal cross section as shown in FIG. There is.

  As shown in FIG. 16, the outer cylindrical portion 312 of the yoke 310 is provided with six magnet mounting surfaces 313, and the substantially flat permanent magnet 42 that can be easily manufactured, is provided with the magnet mounting surface 313. It can be attached in a magnetically attached state.

  In addition, as shown in FIG. 16, the six substantially flat permanent magnets 42 attached to the magnet attachment surface 313 are in a state in which a part of the adjacent substantially flat permanent magnets 42 is in contact with each other. By providing the magnet attachment surface 313, positioning can be easily performed.

  The substantially flat permanent magnet 42 is magnetized so that, for example, the side surface in contact with the magnet mounting surface 313 is an S pole and the surface substantially opposite to the side surface is an N pole. When the permanent magnet 42 is attached to the substantially hexagonal yoke 310, the outer peripheral surface of the inner cylindrical portion 311 of the hexagonal yoke 310 becomes an S pole, and a magnetic field from the substantially flat permanent magnet 42 toward the inner cylindrical portion 311 is formed. Is done.

  Further, in this improved example, the inner cylinder portion 311 of the substantially square yoke 310 is formed in a substantially circular cross section, and the coil accommodated at a predetermined interval from the inner cylinder portion 301 and the substantially flat permanent magnet 41 is also substantially omitted. What was wound by the circle can be used. Since the substantially flat permanent magnet is attached in a substantially hexagonal shape close to a circle, a sufficient driving force can be obtained even if a substantially circular coil is used.

When such a substantially hexagonal yoke is used, a hexagonal ring-shaped magnetic member is used as the magnetic member described above. The width of the hexagonal ring-shaped magnetic member is equal to the thickness of the substantially flat permanent magnet 42.
Hereinafter, another modified example of the yoke will be described.

  Since the circular yoke 30 as shown in FIG. 4 is in contact with the lower end surface of the outer cylindrical portion 32, the area of contact with the outer ring portion 62 of the lower leaf spring 60L is small, and sufficient adhesive strength is obtained. There is a problem that it is vulnerable to shocks.

  As a modified example of the yoke, there is a yoke 320 with an adhesive surface having an adhesive surface with the outer ring portion 62 of the lower leaf spring as shown in FIG.

  A bonding surface of the lower leaf spring with the outer ring portion 62 is formed from a tab-shaped portion 325 formed so as to extend outward in a state of being continuous with the end surface of the outer cylindrical portion 322 of the yoke 320 with bonding surface. It is configured. Therefore, manufacture by integral molding can be performed easily.

  The surface of the lower leaf spring 60L of the tab-shaped portion 325 that contacts the outer ring portion 62 is substantially parallel to the upper surface of the connecting portion 34 of the yoke 320 with the adhesive surface, and is approximately 90 degrees to the end surface of the outer cylindrical portion 322. Since the four are provided at intervals, they come into contact with each other in a wider area than the lower end surface of the outer cylindrical portion 32 from the circular yoke 30, so that the outer ring portion 62 of the lower leaf spring 60L is bonded stably and securely. be able to.

  Further, the outer edge of the tab-shaped portion 325 is substantially linear, and has a contact point 326 with the arc formed by the outer tube portion 322 at the center in the width direction of the tab, and the arc formed by the outer tube portion 322 at the contact point 326. And the outer edge of the tab-like portion 325 substantially coincide with each other. Therefore, the width in the diameter direction of the circular yoke 30 and the width connecting the contact points 326 of the tab-like portions 325 of the yoke 320 with the adhesive surface coincide with each other, compared with the case where the circular yoke 30 is used. Thus, the adhesive surface of the lower leaf spring 60L with the outer ring portion 62 can be increased without changing the external dimensions.

  Further, the four tab-like portions 325 are provided with the recesses 327 between the adjacent tab-like portions, so that the column portion 82 of the cover 80 or the column portion 87 of the base 85 described above is disposed in the recess portion 327 during assembly. The yoke 320 with the adhesive surface can be positioned.

  Further, as shown in FIG. 19, the yoke 330 with a deformable adhesive surface having a flange portion 335 formed so as to extend outward in a state of being continuous with the end surface over the outer periphery of the end surface of the outer cylinder portion 332. There is also. This yoke 330 with a deformable adhesion surface can also adhere to the outer ring portion 62 of the lower leaf spring 60L more stably and more reliably than the circular yoke 30 and can be easily manufactured.

1 is a perspective view of an overall configuration of an embodiment of an autofocus actuator according to the present invention. FIG. 2 is an exploded perspective view of the autofocus actuator shown in FIG. 1. FIG. 2 is a schematic cross-sectional view of the autofocus actuator shown in FIG. 1. It is a perspective view which shows a circular yoke. It is sectional drawing of a yoke, Comprising: The mode of a magnetic field at the time of attaching only a permanent magnet is shown. It is sectional drawing of a yoke, Comprising: The mode of the magnetic field at the time of attaching a permanent magnet and a magnetic material is shown. It is a perspective view which shows a circular ring-shaped magnetic member. It is a top view of a leaf | plate spring. It is a top view of a sheet-like electrode. It is a part of schematic sectional drawing of the actuator for autofocus, Comprising: The state which connected the drawer | drawing-out part of the coil to the sheet-like electrode is shown. It is the elements on larger scale of A in FIG. It is a top view which shows the positional relationship of the flange part of a holder, the drawer part of a coil, and a sheet-like electrode. It is a top view of a stopper. It is a top view which shows the positional relationship of the opening part of a cover, and a stopper. It is a perspective view of a substantially square yoke and shows a state in which a substantially flat permanent magnet is attached. It is a perspective view of a substantially hexagonal yoke, and shows a state where a substantially flat permanent magnet is attached. It is a perspective view which shows a substantially square ring-shaped magnetic member. It is a perspective view of a yoke with a tab. It is a perspective view of the yoke modification with a tab.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Autofocus actuator 10 Holder 11 Cylindrical part 12 Flange part 12a Step part 13 Protrusion 14 Concave part 15 Convex part (Step part)
16 step portion 20 coil 21 lead portion 22 soldering portion 23 dummy wire 24 stress relieving agent 30 yoke 31 inner cylinder portion 32 outer cylinder portion 33 magnet mounting surface 34 connecting portion 35 insertion hole 40 permanent magnet 41 curved in an arc shape 41 flat plate shape Permanent magnet (for nearly square yoke)
42 Flat permanent magnets (for nearly hexagonal yokes)
50 circular ring-shaped magnetic member 51 substantially square ring-shaped magnetic member 60 leaf spring 60U upper leaf spring 60L lower leaf spring 61 inner ring portion 62 outer ring portion 63 connecting portion 65 concave portion of inner ring portion outer edge 66 inner ring portion inner edge Concave part 70 Stopper 71 Opening 72 Substantially triangular concave part 80 Cover 80a Opening part 81 Upper plate part 82 Column part 85 Base 85a Opening part 86 Bottom plate part 86a Opening 87 Column part 88 Insertion hole 89 Projection 90 Sheet electrode 91 Ring-shaped part 92 Extension part 93 Terminal part 94 Cover film 95 Dummy terminal part 100 Lens assembly 200 Opening part 201 Substantially triangular convex part 202 Projecting part 300 Substantially square yoke 301 Inner cylinder part 302 Outer cylinder part 303 Magnet mounting surface 304 Concave Part 310 substantially hexagonal yoke 311 inner cylinder part 312 outer cylinder part 313 magnet mounting surface 320 with adhesive surface Yoke 322 Outer cylinder part 325 Tab-like part 326 Contact point 327 Concave part 330 Deformable bonding surface provided yoke 332 Outer cylinder part 335 Flange part

Claims (8)

A holder having a cylindrical part to which a lens is attached at one end and a flange provided on the outer periphery of the other end of the cylindrical part;
A coil so as to be positioned around the cylindrical portion of the flange portion of the holder;
An inner cylinder part forming an insertion hole through which the cylindrical part of the holder is inserted; and an outer cylinder part provided at a predetermined interval outside the inner cylinder part, the inner cylinder part and the outer cylinder part A yoke that is integrally connected to the end of the holder opposite to the flange portion, and is configured to accommodate the coil in the space of the predetermined interval;
A permanent magnet arranged to face the magnet mounting surface on the inner peripheral surface of the outer cylindrical portion of the yoke at a distance from the coil;
A pair of leaf springs provided on both sides in the optical axis direction of the cylindrical portion of the holder, and supported so as to be displaceable in the optical axis direction with the holder positioned in the radial direction;
Provided on the outside of each of the pair of leaf springs, and sandwiching the leaf springs between both end surfaces in the optical axis direction of the yoke, and at least opening portions corresponding to the lenses attached to the holder. A pair of support frames, and an autofocus actuator that adjusts the position of a lens attached to the holder in the optical axis direction by energizing the coil,
An autofocus actuator, wherein a sheet-like electrode for supplying electric power to the coil is provided on a support frame side surface of a leaf spring on the flange side of the holder.   2. The autofocus according to claim 1, wherein the sheet-like electrode includes a ring-shaped portion formed in a substantially ring shape, and an extending portion extending radially outward from the ring-shaped portion. Actuator.   The coil is wound so that the lead-out portions on both sides of the winding are positioned on the flange portion side of the holder, and the sheet-like electrode extends on the surface of the support frame with the ring-shaped portion. A terminal portion made of a conductor is provided along the portion, and lead portions on both sides of the winding of the coil are connected to the terminal portion of the sheet-like electrode. The described autofocus actuator.   4. The sheet-like electrode according to claim 1, wherein an adhesive layer for adhering to the leaf spring is provided at least on the ring-like portion on the surface opposite to the support frame side. The autofocus actuator according to any one of the above.   5. The extension part according to claim 1, wherein the extension part extends to the outside of the support frame through an insertion hole provided in the support frame on the flange side. Autofocus actuator. A holder having a cylindrical portion with a lens attached to one end;
A coil so as to be positioned around the cylindrical portion of the holder;
A pair of leaf springs provided on both sides in the optical axis direction of the cylindrical portion of the holder, and supported so as to be displaceable in the optical axis direction with the holder positioned in the radial direction;
A permanent magnet facing the coil is provided, and by energizing the coil, the position of the lens attached to the holder in the optical axis direction can be adjusted by the interaction of the magnetic field of the permanent magnet and the magnetic field generated in the coil. And a yoke to
An autofocus actuator comprising: a sheet-like electrode for supplying electric power to the coil provided on the opposite side of the plate spring to the holder.   The autofocus according to claim 6, wherein the sheet-like electrode includes a ring-shaped portion formed in a substantially ring shape and an extending portion extending radially outward from the ring-shaped portion. Actuator.   The coil is wound so that the lead portions on both sides of the winding are located on the sheet-like electrode side, and the sheet-like electrode is a terminal portion made of a conductor on the surface opposite to the plate spring. 8. The autofocus actuator according to claim 16, wherein lead portions on both sides of the coil winding are connected to terminal portions of the sheet-like electrode.

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