JP2009122332A - Lens drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the bonding strength of a spring member serving as a regulating means and a movable body. <P>SOLUTION: A lens drive device 1 includes the movable body (sleeve 13) which holds a lens and is movable in an optical axis direction, a support body (a cover 12, a holder 19 or the like) which supports the movable body through a spring member and a magnetic drive mechanism which drives the movable body in the optical axis direction. The spring member (second leaf spring 15) includes a movable-body-side attachment part 15c which is attached to the end surface of the movable body in the optical axis direction, a support-body-side attachment part 15d which is attached to the support body and an arm part 15e which is formed between the movable-body-side attachment part 15c and the support-body-side attachment part 15d and regulates the movement in the optical axis direction of the movable body. A recessed groove 13b is formed in the end surface (rear end surface 13a) to which the movable-body-side attachment part 15c is attached, of the movable body. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lens driving device that forms an image of a subject by driving a lens in the direction of an optical axis.

  In recent years, as camera-equipped mobile phones equipped with cameras have become popular, opportunities for photographing various subjects using the mobile phones have increased. For example, you can shoot a subject that is far away from the camera lens, such as a friend or landscape (normal shooting), or a subject that is close to the camera lens, such as a bus timetable or petals (close-up shooting) There is a case.

  In close-up photography (macro photography), the lens position of the camera needs to be slightly closer to the subject side than the lens position during normal photography. For this reason, this type of photographic lens system includes a drive mechanism that drives the lens to move in the direction of the optical axis, so that the lens can be moved in the direction of the optical axis by driving the drive mechanism by switching a switch. (For example, refer to Patent Document 1).

  A lens driving device disclosed in Patent Document 1 includes a moving lens body, a driving mechanism that moves the moving lens body in the optical axis direction, a fixed body that supports the moving lens body so as to be movable in the optical axis direction, and a moving lens. And restricting means (plate spring) for restricting movement of the body. The drive mechanism has a magnet and a coil. In such a configuration, an electric force is supplied to the coil to generate an electromagnetic force, while a restricting force that opposes the electromagnetic force is generated by the restricting means, and the size of both is adjusted, thereby making the moving lens body a desired one. Can be stopped in position.

  Here, when the regulating means (plate spring) described above is attached to the moving lens body, it is generally performed by welding or fixing with an adhesive. More specifically, for example, a small pin is provided on the end surface of the moving lens body, and the pin is passed through a hole formed in the restricting means to position both. By applying heat to the pin in this state, the pin is melted, and the restricting means is welded to the moving lens body. In some cases, the vicinity of the welded pin is hardened with an adhesive.

JP 2007-94364 A

  However, for example, a lens driving device mounted on a camera-equipped mobile phone has a very small size, and the above-described pin itself is very small. Therefore, even if bonding or welding is performed with a small pin, the fixing force is not strong, and if a large impact is applied, the regulating means may be detached from the moving lens body. In addition, if the pins are small, a sufficient bonding area between the restricting means and the moving lens body cannot be secured, so there is room for improvement in terms of fixing force in this respect.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a lens driving device capable of improving the adhesive strength between a spring member serving as a restricting means and a moving body.

  In order to solve the above problems, the present invention provides the following.

  (1) A movable body that holds the lens and is movable in the optical axis direction, a support that supports the movable body via a spring member, and a magnetic drive mechanism that drives the movable body in the optical axis direction. In the lens driving device, the spring member includes a moving body-side mounting portion that is attached to an end surface of the moving body in the optical axis direction, a supporting body-side mounting portion that is attached to the supporting body, the moving body-side mounting portion, and the supporting body side. An arm portion that is formed between the movable body and restricts movement of the movable body in the optical axis direction, and a groove is formed on an end surface of the movable body to which the movable body side mounting section is attached. A lens driving device.

  According to the present invention, in the lens driving device having the moving body, the support body, and the magnetic drive mechanism, the spring member is attached to the end face of the moving body in the optical axis direction. A support body side mounting portion to be mounted; and an arm portion that is formed between the mobile body side mounting portion and the support body side mounting portion and restricts movement of the mobile body in the optical axis direction. Since the end face to which the attachment portion is attached is formed with a groove (for example, a concave groove), the adhesive strength between the spring member and the moving body is improved by pouring an adhesive into the groove. Can do.

  That is, when the spring member and the moving body are bonded by the adhesive poured into the groove, the bonding area can be increased as compared with the case where the pins are welded and bonded. Therefore, the adhesive strength between the spring member and the moving body can be improved. Further, if the adhesive strength is improved, the robustness and reliability against impact can be enhanced for the mobile phone equipped with the lens driving device.

  In particular, the lens driving device according to the present invention uses a “continuous” groove to bond the spring member and the moving body continuously compared to the case where the pins are bonded using scattered pins. Can be glued to. Therefore, stronger adhesive strength can be ensured.

  Here, the shape and depth of the “groove” do not matter. Grooves may be formed on all of “the end surface to which the moving body-side attachment portion is attached” or may be formed on a part thereof. Any method may be used for pouring the adhesive into the “groove”.

  (2) The lens driving device characterized in that an injection hole for injecting an adhesive into the groove is formed in the movable body side attachment portion.

  According to the present invention, since the injection hole for injecting the adhesive into the groove is formed in the moving body side attachment portion, the adhesive can be easily poured into the groove through the injection hole, and thus Assembly work can be facilitated. In particular, even when the volume of the lens driving device is small, the assembling operation can be performed more easily by the bonding operation using the injection hole.

  (3) The lens driving device according to claim 1, wherein the moving body side attaching portion has a connecting portion connected to the arm portion, and the injection hole is formed in the vicinity of the connecting portion.

  According to the present invention, the moving body-side mounting portion has the connecting portion connected to the arm portion, and the injection hole described above is formed in the vicinity of the connecting portion. Can be glued to. Specifically, the largest deformation addition in the spring member is the connecting portion (connecting portion) between the moving body side mounting portion and the arm portion. Therefore, the spring member can be more securely bonded to the moving body by forming the injection hole in the vicinity of the connecting portion and preferentially bonding in the vicinity of the connecting portion.

  According to the lens driving device of the present invention, when the spring member and the moving body are bonded, the bonding area can be increased by pouring the adhesive into the groove formed in the moving body, and consequently the moving with the spring member. The adhesive strength with the body can be improved. Further, if the adhesive strength can be improved, the impact resistance (reliability, etc.) of the mobile phone equipped with the lens driving device can be increased.

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

[Machine configuration]
FIG. 1 is a perspective view showing an external configuration of a lens driving device 1 according to an embodiment of the present invention. FIG. 2 is an exploded perspective view showing a mechanical configuration of the lens driving device 1 according to the embodiment of the present invention.

  1 and 2, the lens driving device 1 includes a yoke 11, a cover 12, a sleeve 13, a first plate spring 14, a second plate spring 15, a wire spring 16, a magnet 17, The coil 18 (the first coil 181 and the second coil 182) and the holder 19 are provided.

  Note that the illustration of a lens barrel (lens barrel) incorporating a lens is omitted. The lens driving device 1 also moves the sleeve 13 along the direction of the optical axis L in the A direction (front side) approaching the subject (imaging target) and the B direction (rear side) approaching the opposite side (image side) from the subject. (See FIG. 1). The sleeve 13 holding a lens barrel (not shown as described above) in which one or more lenses are incorporated is configured to be movable in the direction of the optical axis L together with the wire spring 16 and the like. It corresponds to an example of “moving body”. The yoke 11, the cover 12, the holder 19, and the like are an example of a “support” that supports the sleeve 13 and the like so as to be movable in the direction of the optical axis L via the first plate spring 14 and the second plate spring 15. It corresponds to. The sleeve 13 and the like are driven in the direction of the optical axis L by a “magnetic drive mechanism” including a coil 18 and a magnet 17.

  The yoke 11 is made of a ferromagnetic plate such as a steel plate. Further, the yoke 11 is exposed at the front and side surfaces of the lens driving device 1, and a circular incident window 111 is formed at the center of the yoke 11 for taking reflected light from the subject into the lens. On the other hand, the cover 12 is attached to the yoke 11, and a circular incident window 121 is formed at the center of the cover 12 for taking reflected light from the subject into the lens. The holder 19 holds an image sensor (not shown) on the image side.

  The coil 18 includes a first coil 181 and a second coil 182, which are arranged in two stages in the direction of the optical axis L, both of which are annular. Then, it is wound around the outer peripheral surface of the sleeve 13 at a predetermined interval. In addition, eight magnets 17 are arranged in two stages in the optical axis direction. The magnets 17 of each stage are arranged such that the front magnet 17 is against the first coil 181 and the rear magnet 17 is the first. The two coils 182 face each other on the outer peripheral side, and are fixed to four corners on the inner peripheral surface of the yoke 11.

  In the present embodiment, the magnet 17 is magnetized to poles whose inner surface and outer surface are different from each other. For example, the four magnets 17 arranged on the front side are magnetized with the N pole on the inner surface, the outer surface is magnetized with the S pole, and the four magnets 17 arranged on the rear side have an S inner surface. The pole is magnetized and the outer surface is magnetized to the N pole.

  The first plate spring 14 and the second plate spring 15 are both formed from a thin metal plate and have the same thickness in the direction of the optical axis L.

  Since the yoke 11 is larger than the dimension in the optical axis direction of the region where the first coil 181 and the second coil 182 are arranged, and the dimension in the optical axis direction of the magnet 17, the front magnet 17. Leakage flux from the magnetic path configured between the first coil 181 and the magnetic path configured between the front magnet 17 and the second coil 182 can be reduced, and as a result. The linearity between the amount of movement of the sleeve 13 and the current passed through the first coil 181 and the second coil 182 can be improved.

  The lens driving device 1 includes an annular wire spring 16. The wire spring 16 applies a biasing force in the direction of the optical axis L to the sleeve 13 by a magnetic attractive force acting between the wire spring 16 and the magnet 17. For this reason, it is possible to prevent the moving body (sleeve 13 or the like) from being displaced by its own weight when the coil is not energized, and as a result, the moving body (sleeve 13 or the like) can be maintained in a desired posture. Yes. Furthermore, impact resistance can be improved.

  The second leaf spring 15 is composed of two electrically separated spring pieces 15A and 15B, and serves as a medium for supplying current from an external power source to the coil 18, and each of the spring pieces 15A and 15B. Are electrically connected to the winding start and winding end of the coil 18, respectively. The second leaf spring 15 is attached to the rear end surface 13a (see FIG. 4) of the sleeve 13.

  Here, in the lens driving device 1 according to the present embodiment, when the second plate spring 15 is attached to the sleeve 13, the second plate spring 15 is difficult to remove from the sleeve 13. More specifically, a groove 13b in which an adhesive is accumulated is formed on the rear end surface 13a (see FIG. 4) of the sleeve 13, that is, the mounting surface on which the second leaf spring 15 is mounted. Hereinafter, the groove 13b will be described in detail with reference to FIGS. In the present embodiment, the groove 13b is described as being formed on the rear end surface 13a of the sleeve 13. However, the present invention is not limited to this, and may be formed on the front end surface of the sleeve 13. Specifically, a groove in which an adhesive accumulates may be formed on the mounting surface (front end surface of the sleeve 13) on which the first plate spring 14 is mounted.

[Sleeve groove]
FIG. 3 is a perspective view when the holder 19 is removed from the lens driving device 1 and viewed from the rear side. FIG. 4 is a perspective view showing a state when the second leaf spring 15 is removed from the lens driving device 1 shown in FIG. The second leaf spring 15 in FIG. 3 is provided with a frame body 15b and a connecting body 15b ′ that are removed when completed.

  3 and 4, the second leaf spring 15 includes an arcuate sleeve-side attachment portion 15c attached to the rear end surface 13a in the optical axis direction of the sleeve 13 and a holder-side attachment attached to the holder 19 formed of resin. 15d and an arm portion 15e that is formed between the sleeve side attachment portion 15c and the holder side attachment portion 15d and restricts the movement of the sleeve 13 in the optical axis direction. In the present embodiment, the sleeve-side attachment portion 15c has an arc shape, but has substantially the same arc shape as the rear end surface 13a of the sleeve 13. This is because the sleeve side attaching portion 15c is attached to the rear end face 13a of the sleeve 13 and has a predetermined area. The predetermined area means an adhesion area where the adhesive penetrates and spreads as described below and can increase the adhesion strength with the sleeve side rear end surface 13a. In addition, the sleeve side attachment part 15c shown to this embodiment is not limited to circular arc shape.

  The second leaf spring 15 is composed of two spring pieces 15A and 15B which are electrically separated. Each of the spring pieces 15A and 15B has a sleeve side attachment portion 15c, two holder side attachment portions 15d, and two arm portions 15e. In FIG. 3, one sleeve side attachment portion 15c, two holder side attachment portions 15d, and two arm portions 15e provided on the spring piece 15B are illustrated. Moreover, the arm part 15e is extended to the vicinity of the holder side attaching part 15d arrange | positioned at the adjacent corner | angular part.

  An insertion hole into which a protrusion (not shown) of the holder 19 is inserted is formed in the holder-side attachment portion 15d. The holder-side attachment portion 15d is positioned on the holder 19 through this insertion hole and attached to the holder 19. . On the other hand, the sleeve side attachment portion 15c is provided with an engagement hole with which a protrusion 13c formed on the rear end surface 13a of the sleeve 13 is engaged. In FIG. 3, the four protrusions 13c are inserted into the four engagement holes formed in the sleeve side attachment portion 15c.

  Here, conventionally, for example, the second leaf spring 15 is bonded and fixed to the sleeve 13 by crushing the four protrusions 13c and heat-pressing them. However, for example, the lens driving device 1 mounted on a cellular phone is very small, and as a result, the four protrusions 13c are also very small. Therefore, the bonding strength is not sufficient in the above-described thermocompression bonding because the bonding area is narrow. Moreover, the thermocompression bonding operation may be difficult.

  Therefore, in the lens driving device 1 according to the present embodiment, the groove 13b is formed on the end surface (the rear end surface 13a of the sleeve 13) to which the sleeve side attaching portion 15c is attached (see FIG. 4). If an adhesive is poured into the groove 13b, the bonding area between the rear end surface 13a of the sleeve 13 and the sleeve side attachment portion 15c is increased. In addition, the adhesive poured into the groove 13b penetrates between the rear end surface 13a of the sleeve 13 and the sleeve side attaching portion 15c by capillary action. Thereby, the adhesive strength of the rear-end surface 13a of the sleeve 13 and the sleeve side attaching part 15c can be improved.

  Note that the width of the groove 13 b can be adjusted by the size of the sleeve 13. Further, the depth of the groove 13b can be adjusted similarly. Furthermore, the shape of the groove 13b is not limited to a square but may be a triangle or a semicircle.

  Moreover, as an adhesive agent poured into the groove | channel 13b, a thermosetting adhesive agent is mentioned, for example. This adhesive basically has a low viscosity, and when heated, it becomes watery. And when it cools, it begins to form a viscosity, and it has the property of solidifying at room temperature.

  On the other hand, as a method of pouring the adhesive into the groove 13b, for example, the sleeve side attachment portion 15c may be slightly lifted and poured, or a part of the groove 13b is formed on the outer side in the radial direction of the sleeve 13 and It may be poured.

  In particular, in the present embodiment, the sleeve side attachment portion 15c is formed with an injection hole 15a for injecting an adhesive into the groove 13b. As a result, even when the sleeve-side attachment portion 15c is in close contact with the rear end surface 13a of the sleeve 13, the adhesive can be poured through the injection hole 15a.

  The injection hole 15a is formed in the vicinity of the connecting portion 15f that connects the sleeve side attaching portion 15c and the arm portion 15e. Thereby, a location with a large deformation load can be bonded intensively. In addition, by forming the groove 13b only in the vicinity of the connecting portion 15f, the adhesive strength can be efficiently increased with the short-length groove 13b. Specifically, as shown in FIG. 5, the groove 13b may be formed only in the vicinity of the connecting portion 15f.

[basic action]
In the lens driving device 1 according to the present embodiment, the moving body is normally located on the image sensor side (image side) (when the first coil 181 and the second coil 182 are not energized). At this time, the wire spring 16 regulates the displacement of the moving body by a magnetic attractive force acting between the wire 17 and the magnet 17. However, since the distance between the wire spring 16 and the magnet 17 is maintained to some extent, the magnetic attractive force between the wire spring 16 and the magnet 17 does not become too strong. As a result, it is possible to prevent the center axis of the moving body from being shifted, and thus to prevent the tilt characteristics from deteriorating.

  In such a state, when a current is passed through the first coil 181 and the second coil 182, the first coil 181 and the second coil 182 receive an upward (front) electromagnetic force, respectively. As a result, the first coil 181, the second coil 182, and the sleeve 13 begin to move toward the subject side (front side).

  At this time, an elastic force that restricts the movement of the sleeve 13 is generated between the first leaf spring 14 and the front end of the sleeve 13 and between the second leaf spring 15 and the rear end of the sleeve 13. . For this reason, when the electromagnetic force that moves the sleeve 13 forward and the elastic force that restricts the movement of the sleeve 13 are balanced, the sleeve 13 stops. In addition, when a reverse current is passed through the first coil 181 and the second coil 182, the first coil 181 and the second coil 182 receive a downward (rear) electromagnetic force, respectively. .

  At that time, by adjusting the amount of current flowing through the first coil 181 and the second coil 182 and the elastic force acting on the sleeve 13 by the first leaf spring 14 and the second leaf spring 15, the sleeve 13 (moving) Body) can be stopped at a desired position. In addition, by stopping the sleeve 13 using the balance between the electromagnetic force and the elastic force, unlike the case where the members are brought into contact with each other so as to be locked with the locking portion or the like, it is possible to prevent occurrence of a collision sound. .

[Main effects of the embodiment]
According to the lens driving device 1 according to the present embodiment, as described with reference to FIGS. 3 to 5, a groove 13 b into which an adhesive can be poured is formed on the rear end surface 13 a of the sleeve 13. . Thereby, the adhesive strength between the sleeve side attaching portion 15 c and the sleeve 13, that is, the second leaf spring 15 and the sleeve 13 can be improved.

  Further, as shown in FIG. 3, by providing some injection holes 15a in the sleeve side attachment portion 15c, the adhesive can be easily poured into the groove 13b, and as a result, the assembly work can be simplified. In particular, this effect can be achieved even if the lens driving device 1 is small.

  Furthermore, by providing the injection hole 15a in the vicinity of the connecting portion 15f, it is possible to preferentially bond the portion of the second leaf spring 15 where the deformation load is large, and as a result, the second leaf spring 15 is more reliably attached to the sleeve. 13 can be adhered.

  The lens driving device 1 can be attached to various electronic devices other than the camera-equipped mobile phone. For example, PHS, PDA, bar code reader, thin digital camera, surveillance camera, vehicle rear view confirmation camera, door with optical authentication function, and the like.

  The lens driving device according to the present invention is useful as a device capable of increasing the adhesive strength between the second leaf spring and the sleeve.

It is a perspective view which shows the external appearance structure of the lens drive device which concerns on embodiment of this invention. It is a disassembled perspective view which shows the machine structure of the lens drive device which concerns on embodiment of this invention. It is a perspective view when removing a holder from a lens drive device and seeing from the back side. It is a perspective view which shows a mode when a 2nd leaf | plate spring is removed from the lens drive device shown in FIG. It is a figure which shows a mode when the formation position of a groove | channel is limited.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens drive device 11 Yoke 12 Cover 13 Moving body (sleeve)
14 First plate spring 15 Second plate spring 16 Wire spring 17 Magnet 18 Coil 19 Holder

Claims (3)

A movable body that holds the lens and is movable in the optical axis direction;
A support that supports the movable body via a spring member;
In a lens driving device having a magnetic driving mechanism for driving the moving body in the optical axis direction,
The spring member includes a moving body side mounting portion attached to an end surface of the moving body in the optical axis direction, a support side mounting portion attached to the support body, and the moving body side mounting portion and the support side mounting portion. An arm portion that is formed and restricts movement of the movable body in the optical axis direction,
The lens driving device according to claim 1, wherein a groove is formed on an end surface of the moving body to which the moving body side mounting portion is attached.   The lens driving device according to claim 1, wherein an injection hole for injecting an adhesive into the groove is formed in the moving body side mounting portion. The movable body side mounting portion has a connecting portion that connects to the arm portion,
The lens driving device according to claim 2, wherein the injection hole is formed in the vicinity of the connecting portion.

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