JP2009020543A - Lens driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To propose a lens driving device, wherein the energizing force of a spring member which supports a moving body to be movable in an optical axis direction is used for driving the moving body and holding the position thereof. <P>SOLUTION: A fixed body 4 is equipped with: the spring member which supports the moving body 3 to be movable in the optical axis direction F. When the energizing force of the spring member acts so as to always make the moving body 3 go toward a second lens holding position P2 from a first lens holding position P1, the energizing force of the spring member is utilized for moving the lens 2 to the second lens holding position P2 from the first lens holding position P1, and also for holding the lens 2 at the second lens holding position P2. When the energizing force of the spring member acts so as to always make the moving body 3 go toward the first lens holding position P1 from the second lens holding position P2, the energizing force of the spring member is utilized for moving the lens 2 to the first lens holding position P1 from the second lens holding position P2 and also holding the lens 2 in the first lens holding position P1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lens driving device used for a camera such as a camera-equipped mobile phone. More specifically, the present invention relates to a technique for driving and holding a lens in the optical axis direction.

  In a camera device mounted on a camera-equipped mobile phone or the like, the lens is driven between two points: a position for normal shooting and a position slightly closer to the subject by a fixed distance than for normal shooting during close-up shooting. ing. However, such a device cannot be equipped with a lens driving device equipped with a motor in terms of size. For this reason, a camera-equipped mobile phone or the like is equipped with a lens driving device that directly magnetically drives the lens.

Here, as a magnetic drive type lens driving device, conventionally, it has a cylindrical case for holding a lens, a ring-shaped driving magnet attached to the outer periphery of the case, and a driving coil facing the driving magnet, There is a configuration in which the case holding the lens is magnetically driven in the optical axis direction by controlling energization to the drive coil, and the case is magnetically held there (see, for example, Patent Document 1).
JP 2000-187862 A (page 2-3, FIG. 1-3)

  In a type in which a moving body such as a case for holding a lens is magnetically driven in the direction of the optical axis and is magnetically held there, there is a type that includes a spring member that supports the moving body so as to be movable in the direction of the optical axis. is there. However, it has not been proposed how to apply the biasing force of the spring member to the moving body.

  In view of the above problems, an object of the present invention is to propose a lens driving device that can use the urging force of a spring member that supports a moving body so as to be movable in the optical axis direction for driving and holding the position of the moving body. is there.

  In order to solve the above-described problems, the present invention includes a moving body provided with a lens, and a fixed body that holds the moving body so as to be movable in the optical axis direction of the lens, and includes a drive magnet and a drive coil. In the lens driving device configured to move the moving body between a first lens holding position and a second lens holding position in the optical axis direction of the lens by a magnetic driving force, the fixed body is the moving A spring member that supports the body movably in the optical axis direction, and the spring member applies a biasing force so that the movable body always moves from one of the first and second lens holding positions to the other. The urging force of the spring member is applied so that the moving body moves from one of the first and second lens holding positions to the other and the moving body holds the first and second lenses. Other than position Characterized in that it is utilized to hold at.

  If comprised in this way, the urging | biasing force of a spring member is the lens holding | maintenance in a 1st lens holding position, the movement of a lens from a 1st lens holding position to a 2nd lens holding position, a 2nd lens, for example It can be used to move the lens from the holding position to the first lens holding position, or to hold the lens at the second lens holding position.

  In the present invention, the lens is preferably a camera lens of a camera-equipped mobile phone.

  In the present invention, it is preferable that the spring member exerts an urging force so that the movable body always moves from the second lens holding position to the first lens holding position.

  In the present invention, it is preferable that the lens is a lens of a camera, and one of the first lens holding position and the second lens holding position is a position where close-up photography is performed.

  In the present invention, when the moving body is moved from the first lens holding position to the second lens holding position by the magnetic driving force, the moving body is moved by the fixed body at the second lens holding position. It is preferable that the impact is absorbed.

  A lens driving device to which the present invention is applied will be described with reference to the drawings.

[overall structure]
1A, 1B, and 1C are longitudinal sectional views schematically showing a state in which a lens is held at a first lens holding position in a lens driving device to which the present invention is applied. The longitudinal cross-sectional view which shows typically the state in the middle of moving to the 2nd lens holding position from the 1 lens holding position, and the longitudinal cross-sectional view which shows the state which hold | maintained the lens in the 2nd lens holding position It is. FIG. 2 is an enlarged perspective view showing a main part of the lens driving device shown in FIG.

  As shown in FIGS. 1A, 1B, 1C, and 2, the lens driving device 1 is for driving the lens 2 in a thin camera mounted on a camera-equipped mobile phone or the like. The lens moving body 3 including the lens 2 and the moving body 3 are moved between the first lens holding position P1 and the second lens holding position P2 in the optical axis direction F (focusing direction) of the lens 2. Each of these two lens holding positions P1 and P2 includes a fixed body 4 for holding the moving body 3 and a case 5 in which the moving body 3 and the fixed body 4 are housed. In the case 5, an opening is formed on the subject side (above the drawing) and an optical path is secured toward the inside of the apparatus (below the drawing).

  The lens moving body 3 includes a lens 2 and a ring-shaped drive magnet 6 attached to the outer periphery of the lens 2. The drive magnet 6 is attached with an annular back yoke 7 sandwiched between the lens 2 and the back yoke 7 also serves as a lens barrel of the lens 2.

  The fixed body 4 is a cylindrical member that surrounds the outer periphery of the drive magnet 6 and a spring member (not shown) such as a leaf spring or a coil spring that elastically supports the lens moving body 3 so as to be movable in the optical axis direction F of the lens 2. Drive is performed on each side of the drive coil 8, the stator yoke 11 having a U-shaped cross section or a C-shaped cross section so as to surround the drive coil 8, and the first and second lens holding positions P1 and P2. First and second washers 9 and 10 are arranged so as to face each of the end faces 61 and 62 of the magnet 6. Each of the first and second washers 9 and 10 is a ring-shaped magnetic piece made of a ferromagnetic material. Each of the surfaces facing the end surfaces 61 and 62 of the drive magnet 6 is made of a nonmagnetic elastic material. The spacer members 12 and 13 are attached.

Here, the dimension of each part is, for example,
Driving magnet 6
Outer diameter 3.7mm, inner diameter 3.1mm, height 1.6mm
Back yoke 7
Outer diameter 3.1mm, inner diameter 2.9mm, height 1.6mm
Drive coil 8
Outer diameter 4.5mm, inner diameter 4.1mm, height 1.4mm
Washers 9, 10
Outer diameter 3.9mm, inner diameter 3.1mm, height 0.25mm
Stator yoke 11
Outer diameter 4.7mm, inner diameter 3.9mm, height 1.6mm, plate thickness 1.6mm
Spacer members 12, 13
Outer diameter 3.9mm, inner diameter 3.1mm, height 0.1mm
Is set to

  In this embodiment, a neodymium plastic magnet is used as the drive magnet 6 and its bHc is 448 kA / m or more. On the other hand, the drive coil 8 is configured to generate a thrust of 100 mN or more.

[Lens drive operation]
In the lens driving device 1 configured as described above, driving performed on the lens 2 is as follows.

  First, in the state shown in FIG. 1A, the lens 2 (moving body 3) is at the first lens holding position P1, and in this state, the energization to the drive coil 8 is stopped. However, since the drive magnet 6 and the first washer 9 are magnetically attracted via the spacer member 12, the moving body 3 is held at the first lens holding position P1. Therefore, close-up photography can be performed with a camera-equipped mobile phone.

  When the lens 2 (moving body 3) is moved to the second lens holding position P2 from this state, the drive coil 8 is energized. As a result, as shown in FIG. 1 (B), the driving magnet 6 is pulled away from the first washer 9 by the magnetic force generated by the driving coil 8 and the driving magnet 6, and the moving body 3 is shown in FIG. ), The lens is moved to the second lens holding position P2. As a result, the drive magnet 6 and the second washer 10 are magnetically attracted via the spacer member 13. At this time, since the drive magnet 6 abuts against the spacer member 13, the impact is absorbed.

  Here, in a state where the drive magnet 6 and the second washer 10 are magnetically attracted via the spacer member 13, even if the energization to the drive coil 8 is stopped, the moving body 3 remains in the second lens holding position P2. Will be held. Therefore, it is possible to perform normal shooting with a camera-equipped mobile phone.

  Note that the operation of moving the lens 2 (moving body 3) from the second lens holding position P2 to the first lens holding position P1 is the same as the above-described operation, and thus the description thereof is omitted.

  As described above, in this embodiment, when the lens 2 is moved between the first lens holding position P1 and the second lens holding position P2, the driving coil 8 is energized to magnetically drive the moving body 3. When the lens 2 is held at the first lens holding position P1 and the second lens holding position P2, energization to the drive coil 8 is stopped and the magnetic attractive force between the drive magnet 6 and the magnetic pieces 9, 10 is used. To do. Therefore, while the lens 2 is held at the first lens holding position P1 or the second lens holding position P2, it is not necessary to energize the drive coil 8, so that power consumption can be kept low.

  Here, although not shown, the fixed body 4 includes a spring member that supports the movable body 3 so as to be movable in the optical axis direction F. Therefore, the urging force of the spring member is applied to the movable body 3 (lens). It can be used for driving and position holding in 2).

  That is, when the urging force of the spring member always acts to move the moving body 3 from the first lens holding position P1 to the second lens holding position P2, the urging force of the spring member is applied to the first lens. It can be used to move the lens 2 from the holding position P1 to the second lens holding position P2, and to hold the lens 2 at the second lens holding position P2. On the other hand, when the biasing force of the spring member always acts to move the moving body 3 from the second lens holding position P2 to the first lens holding position P1, the biasing force of the spring member is changed to the first biasing force. The second lens holding position P2 can be used for moving the lens 2 from the first lens holding position P1 and for holding the lens 2 at the first lens holding position P1. Further, when the biasing force of the spring member is acting in a direction in which the movable body 3 is to be held between the second lens holding position P2 and the first lens holding position P1, the biasing force of the spring member is used. Can be used to move the lens 2 from the first lens holding position P1 to the second lens holding position P2, and to move the lens 2 from the second lens holding position P2 to the first lens holding position P1.

  In the above example, a drive magnet 6 is attached to the movable lens 2, and a drive magnet 8 is arranged on the fixed body 4. On the other hand, a drive coil may be attached to the movable lens 2 and a drive magnet may be disposed on the fixed body 4 to form a voice coil (moving coil) type. However, the configuration of this embodiment can be simplified. There are advantages.

(Effects of this embodiment)
As described above, in the lens driving device according to the present invention, when the moving body including the lens is moved between the first lens holding position and the second lens holding position, the driving body is energized by energizing the driving coil. However, when the lens is held at the first lens holding position, energization to the drive coil is stopped and the magnetic attractive force between the drive magnet and the first magnetic piece is used. Therefore, while the lens is held at the first lens holding position, it is not necessary to energize the drive coil, so that power consumption can be kept low. Also, when the lens is held at the second lens holding position, it is possible to stop the energization of the drive coil and use the magnetic attractive force between the drive magnet and the second magnetic piece. Therefore, it is not necessary to energize the drive coil while the lens is held at the second lens holding position, so that power consumption can be kept low.

(A), (B), and (C) are longitudinal sectional views schematically showing a state in which the lens is held at the first lens holding position in the lens driving device to which the present invention is applied. FIG. 6 is a longitudinal sectional view schematically showing a state in the middle of moving from the lens holding position to the second lens holding position, and a longitudinal sectional view schematically showing a state in which the lens is held at the second lens holding position. . It is a perspective view which expands and shows the principal part of the lens drive device shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens drive device 2 Lens 3 Moving body 4 Fixed body 5 Case 6 Drive magnet 7 Back yoke 8 Drive coil 9, 10 Washer 11 Stator yoke 12, 13 Spacer member

Claims (5)

A movable body having a lens, and a fixed body that holds the movable body in a direction that allows movement of the movable body in the optical axis direction of the lens. In the lens driving device configured to move between the first lens holding position and the second lens holding position in the axial direction,
The fixed body includes a spring member that supports the movable body so as to be movable in the optical axis direction.
The spring member applies an urging force so that the moving body always moves from one of the first and second lens holding positions to the other,
The urging force of the spring member is the movement of the movable body from one of the first and second lens holding positions to the other and the movable body at the other of the first and second lens holding positions. A lens driving device used for holding. In claim 1,
The lens driving device according to claim 1, wherein the lens is a lens of a camera phone. In claim 1 or 2,
The lens driving device according to claim 1, wherein the spring member applies an urging force so that the movable body always moves from the second lens holding position to the first lens holding position. In any one of claims 1 to 3,
The lens is a lens of a camera;
One of the first lens holding position and the second lens holding position is a position for performing close-up photography. In any one of claims 1 to 4,
When the moving body is moved from the first lens holding position to the second lens holding position by the magnetic driving force, the moving body is absorbed by the fixed body at the second lens holding position. A lens driving device characterized by that.

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