JP2007226011A - Lens drive unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens drive unit capable of enhancing various efficiency by reducing a dead space. <P>SOLUTION: The lens drive unit 10 includes: a lens holder 12 for holding a lens; a magnet 17; coils (coil 14 and coil 14'); and also, a magnetic driving part for moving the lens holder 12 in the optical axis direction of the lens and a cover part (yoke 16 and holder receiver 19 etc.) for covering all of or a part of the lens holder 12 and the magnetic driving part, on the outside of the lens holder 12. The magnet 17 is formed to a shape along the inner periphery of the cover part. <P>COPYRIGHT: (C)2007,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).

  The lens driving device disclosed in Patent Document 1 includes a lens holder that holds a lens, a magnetic drive unit (including a magnet and a coil) that moves the lens holder in the optical axis direction of the lens, a lens holder, and a magnetic And a cover part that covers all or part of the drive part. And since the lens holder located in the approximate center of a lens drive device is cylindrical shape, the components (magnet or coil) surrounding the periphery also have a ring shape (donut shape).

Japanese Patent Laying-Open No. 2005-37865 (FIG. 7)

  However, since the recent external design of the lens driving device has a square (prism) shape in consideration of positioning and assembling properties, as described above, when the magnets and coils are in an annular shape, they are wasted at the four corners in the lens driving device. There was a disadvantage that a new space was born. In other words, when designing the shape of the magnet or coil, the actual situation is that there is a consciousness that the inner peripheral shape of the magnet or coil needs to be in line with the shape of the lens holder (cylindrical shape). It is. Therefore, the outer peripheral shape of the magnet and coil is also formed in an annular shape like the inner peripheral shape, and there is a useless space between the magnet or coil and the lens driving device (cover portion) formed in a square shape. It has occurred.

  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 various efficiencies by reducing a useless space.

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

  (1) A lens holder that holds a lens, a magnet and a coil, and a magnetic drive unit that moves the lens holder in the optical axis direction of the lens outside the lens holder; and the lens holder and the magnetic drive unit A lens driving device having a cover portion that covers all or a part of the lens driving device, wherein the magnet has a shape along an inner peripheral shape of the cover portion.

  According to the present invention, a lens holder, a magnetic drive unit that includes a magnet and a coil, and moves the lens holder in the optical axis direction of the lens, and a cover unit that covers all or part of the lens holder and the magnetic drive unit, In the lens driving device having the above configuration, the shape of the magnet is made to conform to the inner peripheral shape of the cover portion, so that the magnet can be filled in a place that has become a wasteful space in the conventional lens driving device.

  Therefore, the useless space between the magnet and the cover part can be reduced at the four corners in the lens driving device (cover part), and the magnetic force of the magnet can be strengthened accordingly, and the lens holder can be removed. The driving force for moving the lens in the optical axis direction can be strengthened.

  And since the driving force of a lens holder can be strengthened, without changing the electric current sent through a coil compared with the conventional lens drive device, the drive efficiency of a lens holder can be improved. On the other hand, even if the current flowing through the coil is reduced, the driving force of the lens holder can be ensured as in the conventional case, so that the energy saving efficiency can be increased.

  (2) A lens holder that holds the lens, a magnet and a coil, and a magnetic drive unit that moves the lens holder in the optical axis direction of the lens on the outside of the lens holder; and the lens holder and the magnetic drive unit A cover part that covers all or part of the cover, wherein the cover part includes at least one plane, and the magnet follows the cover part inner periphery. A lens driving device characterized by having a shape.

  According to the present invention, a lens holder, a magnetic drive unit that includes a magnet and a coil, and moves the lens holder in the optical axis direction of the lens, and a cover unit that covers all or part of the lens holder and the magnetic drive unit, Since the shape of the magnet is the shape along the inner peripheral shape (including at least one plane) of the cover part, the magnet is filled in a place that was wasted in the conventional lens driving device. As a result, the driving efficiency when the lens holder is moved in the optical axis direction of the lens can be increased.

  (3) The lens driving device according to (1) or (2), wherein the magnet and the cover are positioned at each other's corner.

  According to the present invention, since the magnet and the cover part are positioned at the corners of each other, a jig or the like for positioning the magnet on the cover part becomes unnecessary, and the working efficiency can be improved.

  (4) The lens driving device according to any one of (1) to (3), wherein the shape of the coil is a shape along an inner peripheral shape of the cover portion.

  According to the present invention, since the shape of the coil described above is also a shape along the inner peripheral shape of the cover portion, the coil is disposed in a place that has been wasted space in the conventional lens driving device. Can do.

  Therefore, the useless space between the coil and the cover portion can be reduced at the four corners in the lens driving device (cover portion), so that a lot of coils can be wound, and as a result, the driving efficiency of the lens holder. It is possible to increase energy efficiency.

  (5) When a current is supplied to the coil to generate an electromagnetic force, the coil holder includes a restricting unit that restricts the movement of the lens holder based on the electromagnetic force. The lens driving device according to any one of (1) to (4), wherein the lens driving device has a shape along a circumferential shape.

  According to the present invention, the lens driving device is provided with the restricting means for restricting the movement of the lens holder based on the electromagnetic force when current is supplied to the coil to generate the electromagnetic force, and the shape of the restricting means is changed to the cover portion. Therefore, the restricting means can be disposed in a place where the conventional lens driving device has become a useless space. Accordingly, it is possible to obtain a greater restricting force than that of the conventional lens driving device, and thus it is possible to improve the stability when holding the lens holder.

  (6) Any one of (1), (3), (4), and (5), wherein the outer peripheral shape and the inner peripheral shape of the cover portion are substantially quadrangular shapes having chamfered portions at corner portions. Or a lens driving device.

  According to the present invention, the outer peripheral shape and the inner peripheral shape of the cover portion described above are substantially square shapes with chamfered portions at the corner portions, so that magnets and coils can be easily inserted into the cover portion, thereby improving workability. Can be improved.

  (7) The outer peripheral shape of the magnet is substantially rectangular and is formed along the inner peripheral surface of the cover portion, and the inner peripheral shape is formed in a circular shape along the outer peripheral shape of the lens holder. The lens driving device according to any one of (1), (3), (4), (5) and (6).

  According to the present invention, the outer peripheral shape of the magnet is substantially rectangular and formed along the inner peripheral surface of the cover portion, and the inner peripheral shape is formed circularly along the outer peripheral shape of the lens holder. Therefore, it is possible to reduce a useless space between the magnet and the cover part while improving the driving efficiency of the lens holder while keeping the shape along the general lens holder shape (cylindrical shape). . In addition, current use efficiency and energy saving efficiency can be increased. Furthermore, positioning of a magnet etc. can be made easy.

  According to the lens driving device of the present invention, since the magnet and the coil in the lens driving device are formed along the inner peripheral shape of the cover portion, the conventional lens driving device has no useless space. It is possible to fill a magnet with a magnet or place a coil in the same place, and as a result, it is possible to increase the driving efficiency of the lens holder and to increase the current utilization efficiency and the energy saving efficiency.

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

  FIG. 1 is an external view showing an external configuration of a lens driving device 10 according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing an internal configuration of the lens driving device 10 shown in FIG. 2A is a longitudinal sectional view of the lens driving device 10 shown in FIG. 1 when cut in the optical axis direction of the lens. Further, in the lens driving device 10 shown in the longitudinal sectional view of FIG. 1A, a plan sectional view taken along the one-dot chain line AA ′ is FIG. FIG. 2C is a plan cross-sectional view when cut along a chain line. In FIG. 2A, for convenience of explanation, the upper side is the front side close to the subject, and the lower side is the rear side close to the camera body rear surface. Further, in the lens driving device 10 shown in FIG. 2A, the right side shows no energization and the left side shows energization.

  1 and 2, the lens driving device 10 mainly includes a lens holder 12 that holds a lens (including a lens barrel), and a cover portion that covers the lens holder 12, the coils 14, 14 ', and the magnet 17 (this embodiment). In the form, it is composed of an upper cover 11, a yoke 16, and a holder receiver 19). The coils 14 and 14 'and the magnet 17 function as an example of a magnetic drive unit that moves the lens holder 12 in the optical axis direction of the lens.

  As shown in FIG. 1, the upper cover 11 and the holder receiver 19 can be fitted into the yoke 16. A magnet 17 is fixed to the inner peripheral surface of the yoke 16. That is, the magnet 17 is fixed to the yoke 16 so as to protrude inward from the inner peripheral surface of the yoke 16 (see FIG. 2A), and is magnetized in a direction orthogonal to the optical axis direction of the lens. (The inward in the radial direction is the N pole, and the outward in the radial direction is the S pole). The yoke 16 is made of a ferromagnetic material such as a steel plate.

  As shown in FIG. 2A, on the outer periphery of the lens holder 12, a coil 14 is fixed on the front side, and a coil 14 'is fixed on the rear side. That is, on the outer periphery of the lens holder 12, the coil 14 is disposed in front of the magnet 17 so as to face the magnet 17, and the magnet 17 is interposed in the optical axis direction of the lens in relation to the coil 14. Thus, the coil 14 'is arranged. As a result, the rear end surface of the coil 14 and the front end surface of the magnet 17 face each other, and the front end surface of the coil 14 ′ and the rear end surface of the magnet 17 face each other. In the present embodiment, the number of turns of the coils 14 and 14 'is the same, but they may be different.

  The magnetic flux emitted from the N pole of the magnet 17 returns to the magnet 17 again after passing through the lens holder 12, the coil 14, and the yoke 16, for example. Further, the magnetic flux emitted from the N pole of the magnet 17 returns to the magnet 17 again after passing through the lens holder 12, the coil 14 ′, and the yoke 16, for example. Therefore, a magnetic circuit (magnetic path) is formed by members such as the lens holder 12, the coil 14, the coil 14 ', and the yoke 16. In this case, it is preferable to use a magnetic material as the material of the lens holder 12. The lens holder 12 can be removed from the material constituting the magnetic circuit (magnetic path).

  The distance between the opposing surfaces of the coil 14 and the coil 14 'is larger than the thickness of the magnet 17 in the optical axis direction of the lens, and the distance between the magnet 17 and the coil 14 (or coil 14') is in the optical axis direction of the lens. A gap is generated, and the lens holder 12 integrated with the coil 14 and the coil 14 ′ can move in the optical axis direction of the lens within the range of the gap.

  In the center of the front side of the upper cover 11, a circular incident window 18 is provided for taking reflected light from the subject into the lens.

  The movement of the lens holder 12 is regulated by a leaf spring 13 and a leaf spring 13 ′. That is, when an electromagnetic force is generated by supplying current to the coil 14 and the coil 14 ', the movement of the lens holder 12 based on the electromagnetic force is regulated by the leaf spring 13 and the leaf spring 13'. . Of these, the leaf spring 13 'will be described in detail with reference to FIG.

  In FIG. 2C, the leaf spring 13 ′ attached to the holder receiver 19 is engaged with a rotation preventing groove 19 a formed on the holder receiver 19. The plate spring 13 'is a metal spring that allows current to flow, and the rear end of the lens holder 12 is placed on the innermost circumferential portion 13'a. Further, three terminals 13'b for energizing the coil 14 'are formed in the circumferential portion 13'a (see FIG. 2 (c)), and current is supplied to the coil 14' through the terminal 13'b. Can be supplied.

  Although a detailed description is omitted here, the leaf spring 13 is also provided with a terminal for energizing the coil 14 in the same manner as the leaf spring 13 ', and a current can be passed through the coil 14 through the terminal. it can. As a result, the leaf spring 13 and the leaf spring 13 ′ can function as the energization wiring for the coil 14 and the coil 14 ′.

  Although not shown in FIG. 2A, the coil 14 and the coil 14 ′ are provided with energization wiring along the lens holder 12. Thereby, the current flowing through the coil 14 and the current flowing through the coil 14 'can be made equal, and current control is facilitated.

  Here, as shown in FIG. 2B, in the lens driving device 1 according to this embodiment, the magnet 17 has a shape along the inner peripheral shape of the cover portion (yoke 16). That is, the outer peripheral shape of the magnet 17 is a substantially square shape, and is formed along the inner peripheral surface of the yoke 16. Further, the inner peripheral shape of the magnet 17 is formed in an annular shape (circular shape) along the outer peripheral shape of the lens holder 12. Moreover, the magnet 17 and the cover part (yoke 16) are positioned by the chamfered part 16a formed in the corner | angular part. Further, the magnet 17 is divided into four, and a gap X is formed between the magnets 17.

  On the other hand, as shown in FIG. 2B, in the lens driving device 1, the shape of the coil 14 ′ (see the dotted line portion in the drawing) is a shape along the inner peripheral shape of the cover portion (yoke 16). The coil 14 'and the cover part (yoke 16) are positioned by a chamfered part 16a formed at a corner part.

  The operation of the lens driving device 1 having the above-described configuration will be described with reference to FIG. As described above, in FIG. 2 (a), the right side indicates no energization and the left side indicates energization.

  On the right side of FIG. 2A (when not energized), the magnetic flux emitted from the N pole of the magnet 17 passes through the lens holder 12 → the coil 14 → the yoke 16 in this order. Of course, if leakage flux is taken into consideration, the magnetic flux emitted from the N pole of the magnet 17 may return only through the coil 14. On the other hand, the magnetic flux emitted from the N pole of the magnet 17 passes in the order of the lens holder 12 → coil 14 ′ → yoke 16. Of course, if the leakage magnetic flux is taken into consideration, the magnetic flux emitted from the N pole of the magnet 17 may return only through the coil 14 '. Therefore, a magnetic circuit (magnetic path) is formed by members such as the lens holder 12, the coil 14, the coil 14 ', and the yoke 16.

  In such a state, currents in the same direction are passed through the coil 14 and the coil 14 '. Then, the energized coil 14 and the coil 14 'placed in the magnetic field each receive an upward (front) electromagnetic force. Thereby, the lens holder 12 to which the coil 14 and the coil 14 'are fixed starts to move to the front side. In the present embodiment, as described above, the lens holder 12 is provided with energization wiring (not shown), and the current flowing through the coil 14 is equal to the current flowing through the coil 14 '. Therefore, substantially equal electromagnetic force acts on the coil 14 and the coil 14 '. Further, since the size of the lens driving device 10 is small (for example, the outer diameter is approximately 10 mm × the height is approximately 5 mm), it is considered that the magnetic flux passing through the coil 14 and the magnetic flux passing through the coil 14 ′ are substantially equal.

  When the lens holder 12 starts to move forward, the force that restricts the movement of the lens holder 12 between the leaf spring 13 and the front end of the lens holder 12 and between the leaf spring 13 ′ and the rear end of the lens holder 12. Occurs. For this reason, the lens holder 12 stops when the electromagnetic force that moves the lens holder 12 forward and the elastic force that restricts the movement of the lens holder 12 are balanced. In this manner, the lens holder 12 is stopped at a desired position by adjusting the amount of current flowing through the coil 14 and the coil 14 'and the elastic force acting on the lens holder 12 by the leaf spring 13 and the leaf spring 13'. be able to.

  Here, as described with reference to FIG. 2B, in the lens driving device 10, the magnet 17 has a shape along the inner peripheral shape of the cover portion (yoke 16). The driving efficiency can be enhanced. That is, in detail with reference to FIG. 3, in the conventional lens driving device 10 ′ shown in FIG. 3A, the magnet 17 outside the lens holder 12 has an annular shape (ring shape). Therefore, useless spaces 30 formed by the magnet 17 and the yoke 16 exist at the four corners in the lens driving device 10. However, as shown in FIG. 3B, according to the lens driving device 10 according to the present embodiment (for convenience of explanation, the chamfered portion 16 a of the yoke 16 is omitted), the conventional lens driving device 10 ′ Since the magnet 17 can be filled in a place where there is a useless space 30 (see FIG. 3A), the magnetic force of the magnet 17 can be strengthened accordingly. Therefore, in the above-described magnetic circuit (magnetic path), the amount of magnetic flux passing through the lens holder 12 → the coil 14 / the coil 14 ′ → the yoke 16 can be increased. As a result, the current flowing through the coil 14 and the coil 14 ′ can be increased. Even if it is not increased, the electromagnetic force acting on the coil 14 and the coil 14 'can be increased, and as a result, the driving efficiency of the lens holder 12 can be enhanced. In addition, the amount of magnetic flux in the magnetic circuit is increased, so that the driving force of the lens holder 12 can be obtained in the same manner as before even if the current flowing through the coil 14 and the coil 14 'is reduced. Can be increased.

  Moreover, since the magnet 17 and the cover part (yoke 16) are positioned at the corners of each other, a jig or the like is not required, and the working efficiency can be improved. Further, as shown in FIG. 2B, in the lens driving device 10, since the shape of the coil 14 and the coil 14 ′ is also the shape along the inner peripheral shape of the cover portion (yoke 16), the coil 14 and the coil 14 are arranged. 'And the yoke 16 can be reduced in wasted space, so that many coils can be wound, which in turn can increase the driving efficiency of the lens holder 12 and increase the energy saving efficiency. it can.

  Furthermore, since the outer peripheral shape and inner peripheral shape of the cover part (yoke 16) are substantially rectangular with chamfered parts 16a at the corners, the magnet 17, the coil 14 and the coil 14 'are used as the cover part (yoke 16). It becomes easy to insert, and as a result workability can be improved.

[Modification]
In the lens driving device 10 described above, the leaf springs 13 and 13 ′ are formed in an annular shape (ring shape) (see FIG. 2C). For example, these are also cover portions (yoke 16 or holder receiver 19). ) Along the inner peripheral shape. As a result, the leaf springs 13 and 13 'can be disposed in a place where the space has been wasted in the past, so that a greater regulating force than in the past can be obtained, and the lens holder 12 can be held (or regulated). ) To improve stability.

  FIG. 4 is a plan sectional view showing a mechanical configuration of a lens driving apparatus 10A according to the second embodiment of the present invention. In FIG. 4, the coil 14 ′ is omitted.

  In the lens driving device 10 </ b> A, the inner peripheral shape of the yoke 16 includes one flat surface 16 b. Therefore, even in the lens driving device 10A having such a cover portion, a useless space can be saved, and as a result, driving efficiency when the lens holder 12 is moved in the optical axis direction of the lens can be improved.

  FIG. 5 is a plan sectional view showing a mechanical configuration of a lens driving device 10B according to the third embodiment of the present invention.

  As shown in FIG. 5, in the lens driving device 10B, although the magnet 17 has a shape along the inner peripheral shape of the yoke 16, the coil 14 'has an annular shape (ring shape). Thus, it is possible to make only the magnet 17 a shape along the inner peripheral shape of the yoke 16.

  FIG. 6 is a plan sectional view showing a mechanical configuration of a lens driving device 10C according to the fourth embodiment of the present invention.

  As shown in FIG. 6, in the lens driving device 10 </ b> C, the coil 14 ′ has an annular shape (ring shape) (while the shape is the same as the shape shown in FIG. 2B), while the magnet 17 has a rectangular shape. It has become. Thereby, although the area facing the coil 14 ′ (coil 14) is reduced, the adhesion area of the magnet 17 can be increased.

  The lens driving devices 10 to 10C as described above can be attached to various electronic devices in addition to 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 that can reduce various useless spaces and improve various efficiencies.

It is an external view which shows the external appearance structure of the lens drive device which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the internal structure of the lens drive device shown in FIG. It is a comparison figure of the conventional lens drive device and the lens drive device shown in FIG. It is a plane sectional view showing the machine composition of the lens drive concerning a 2nd embodiment of the present invention. It is a plane sectional view showing the machine composition of the lens drive concerning a 3rd embodiment of the present invention. It is a plane sectional view showing the machine composition of the lens drive concerning a 4th embodiment of the present invention.

Explanation of symbols

10 to 10 C lens driving device 11 upper cover 12 lens holder 13, 13 ′ leaf spring 14, 14 ′ coil 16 yoke 17 magnet 18 incident window 19 holder receiver

Claims (7)

A lens holder for holding the lens;
A magnetic drive unit including a magnet and a coil, and moving the lens holder in the optical axis direction of the lens outside the lens holder;
A lens driving device having the lens holder and a cover portion covering all or part of the magnetic driving portion,
The lens driving device according to claim 1, wherein the magnet has a shape along an inner peripheral shape of the cover portion. A lens holder for holding the lens;
A magnetic drive unit including a magnet and a coil, and moving the lens holder in the optical axis direction of the lens outside the lens holder;
A lens driving device having the lens holder and a cover portion covering all or part of the magnetic driving portion,
The inner peripheral shape of the cover part includes at least one plane,
The lens driving device according to claim 1, wherein the magnet has a shape along an inner peripheral shape of the cover portion.   The lens driving device according to claim 1, wherein the magnet and the cover are positioned at corners of each other.   4. The lens driving device according to claim 1, wherein a shape of the coil is a shape along an inner peripheral shape of the cover portion. 5. When an electric force is supplied to the coil to generate an electromagnetic force, there is a restricting means for restricting the movement of the lens holder based on the electromagnetic force,
5. The lens driving device according to claim 1, wherein a shape of the restricting unit is a shape along an inner peripheral shape of the cover portion.   6. The lens driving device according to claim 1, wherein the outer peripheral shape and the inner peripheral shape of the cover portion are substantially square shapes each having a chamfered portion at a corner portion.   The outer peripheral shape of the magnet is substantially rectangular and is formed along the inner peripheral surface of the cover part, and the inner peripheral shape is formed in a circular shape along the outer peripheral shape of the lens holder. The lens driving device according to any one of claims 1, 3, 4, 5, and 6.

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