JP2006072165A - Lens driving apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens driving apparatus having an impact-resistant structure while accomplishing the miniaturization. <P>SOLUTION: The lens driving apparatus is provided with a fixed frame 10 having a cylindrical part 12, a lens frame 20 supported so that it may freely move in the optical axis direction L in the cylindrical part 12, and also, for holding lenses G1 to G3, and a cam ring 30 freely rotatably supported in the cylindrical part 12, also, having a cam part 32 for imparting a cam operation in the optical axis direction L while engaging with a cam follower part 21, the cam part 32 is formed so that it can be elastically deformed with the impulsive force applied on the lens frame 20. By having such the constitution, the cam part 32 has a cam function and also an impact absorbing function, then, the impact-resistant structure is obtained while accomplishing the miniaturization. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lens driving device that moves a lens in an optical axis direction, and more particularly to a lens driving device that is applied to a camera mounted on a portable information terminal such as a mobile phone or a portable personal computer.

A camera mounted on a portable information terminal such as a mobile phone or a portable personal computer needs to be as small as possible since the mounting space allowed in the portable information terminal is small. In addition, in order for the camera mounted on the portable information terminal to have a macro switching function for switching between a close-up shooting position (macro shooting position) and another shooting position, a zoom function, or a focusing function, the lens is attached to the optical axis. A lens driving device that moves in the direction is required. As a lens driving device, one using a cam mechanism is known. (For example, refer to Patent Document 1).
In the lens driving device mounted on the portable information terminal, the lens frame exposed to the outside of the device may receive an impact in a direction substantially along the optical axis direction, and the cam or the lens frame may be damaged. For this reason, it is necessary to provide an impact absorbing mechanism in the lens driving device.
JP-A-10-170809

  However, if the shock absorbing mechanism is configured using a spring or the like, the structure becomes complicated and it becomes difficult to reduce the size of the lens driving device so that it can be mounted on a portable information terminal.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a lens driving device having a structure that is resistant to impact while achieving downsizing.

A lens driving device according to the present invention includes a fixed frame having a cylindrical portion that extends in the optical axis direction, a lens frame that is movably supported in the optical axis direction inside the cylindrical portion and holds a lens, and a cylindrical shape A cam ring having a cam portion that is rotatably supported outside the portion and engages with a cam follower portion formed on the lens frame and exerts a cam action in the optical axis direction. It is characterized by being formed to be elastically deformable.
According to this configuration, when the cam ring is rotated, the lens frame moves in the optical axis direction due to the engagement between the cam portion and the cam follower portion, and the photographing position can be changed. When an impact force acts on the frame, the cam portion is elastically deformed and the impact force is absorbed or alleviated. In this way, by providing the cam portion with the cam function for moving the lens frame in the optical axis direction together with the impact absorbing function or the impact mitigating function, it is possible to achieve a structure that is resistant to impact while realizing downsizing of the apparatus.

In the above configuration, the cam follower portion may be slidably connected to the cam portion so as to maintain the engagement with the cam portion in the optical axis direction.
According to this configuration, since the cam follower portion is slidably connected to the cam portion so as to maintain the engagement, the cam follower portion is urged by the spring or the like to maintain the engagement between the cam follower portion and the cam portion. There is no need, and the device configuration can be simplified.

The said structure WHEREIN: The cam part can employ | adopt the structure currently formed integrally with the cam ring.
According to this configuration, the number of parts of the device can be reduced and the structure of the device can be simplified.

In the above configuration, the cam portion may be formed in a leaf spring shape.
According to this configuration, the cam portion can be formed to be elastically deformable with a relatively simple structure.

In the above configuration, the cam portion may be formed in a cantilever shape.
According to this configuration, the cam portion can be easily formed integrally with the cam ring by, for example, injection molding using a resin or press molding using a metal plate, and a relatively large elastic deformation amount can be obtained. It is done. Further, when the cam follower portion is slidably connected to the cam portion, the cam follower portion can be easily assembled using the free end portion of the cam portion.

The said structure WHEREIN: The structure which is formed so that a cam part may be slidably clamped in an optical axis direction can be employ | adopted for a cam follower part.
According to this configuration, the contact state between the cam portion and the cam follower portion can always be maintained.

In the above configuration, the cam follower portion includes two projecting pieces formed so as to be able to contact the cam surface of the cam portion and to face each other in the optical axis direction, and the facing surface of the projecting piece is curved in a convex shape. The configuration can be adopted.
According to this configuration, the cam portion can be clamped and a smooth cam action can be obtained. Further, even when the cam portion is elastically deformed and the inclination angle thereof changes, the relative movement between the cam portion and the cam follower portion is performed smoothly.

In the above configuration, a configuration in which a plurality of cam portions are formed at equal intervals in the circumferential direction of the cam ring can be employed.
According to this configuration, the cam ring uniformly cams in the circumferential direction with respect to the lens frame, so that the lens frame is smoothly driven in the optical axis direction.

In the above configuration, the cylindrical portion has a guide hole through which the cam follower portion is inserted to guide the lens frame so as to be movable in the optical axis direction.
According to this configuration, since the lens frame is moved in the optical axis direction in a state where the rotation is restricted, it is possible to prevent the photographed image from being changed due to the rotation of the lens at the time of macro switching, zooming, or focusing.

  According to the lens driving device of the present invention, it is possible to achieve a structure that is resistant to impact while achieving downsizing.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described with reference to the accompanying drawings.
1 to 6 show an embodiment of a lens driving device according to the present invention. FIG. 1 is a perspective view showing the appearance of the device, and FIG. 2 is a cross section in the optical axis direction of the device at a normal photographing position. 3 is a sectional view in the optical axis direction of the apparatus, FIG. 4 is an exploded perspective view of the apparatus, FIG. 5 is a perspective view of the cam ring, and FIG. 6 is a sectional view in the optical axis direction of the apparatus at the close-up position. FIG.

As shown in FIGS. 1 to 4, this apparatus is rotatable to a fixed frame 10 that holds a CCD 100 and an IR filter 101 as a solid-state imaging device, a lens frame 20 that holds lenses G1 to G3, and a fixed frame 10. A cam ring 30 that is supported and engages with the lens frame 20 to exert a cam action in the optical axis direction is provided.
In this apparatus, subject light enters the lenses G <b> 1 to G <b> 3 from the front in the optical axis direction L, passes through the IR filter 101, and forms an image on the imaging surface of the CCD 100. The camera unit is formed by holding the CCD 100 on the fixed frame 10.

The fixed frame 10 is made of a resin, and as shown in FIGS. 1 to 4, a base portion 11 having a disk-like outer shape that holds the CCD 100 and the IR filter 101 at the center, and the optical axis direction L from the front surface of the base portion 11. Is provided with a cylindrical portion 12 extending in a cylindrical shape.
The cylindrical portion 12 has an outer peripheral surface 12a formed of a cylindrical surface on which an inner peripheral surface 31a described later of the cam ring 30 is slidably fitted, an optical path through which subject light passes, and an outer peripheral surface described later of the lens frame 20 An inner peripheral surface 12b made of a cylindrical surface 20a is slidably fitted, and three guide holes 13 are arranged at equal intervals in the circumferential direction and formed to extend in the optical axis direction L. .
The cylindrical portion 12 is configured such that the cam ring 30 is rotatably fitted to the outer peripheral surface 12a, so that the cam ring 30 is rotatably supported, and an outer peripheral surface 20a (described later) of the lens frame 20 is fitted to the inner peripheral surface 12b. Thus, the lens frame 20 is supported so as to be movable in the optical axis direction L. Further, the cylindrical portion 12 is guided so as to be movable in the optical axis direction L while restricting rotation of the lens frame 20 around the optical axis by inserting a cam follower portion 21 described later of the lens frame 20 into the guide hole 13. To do. As a result, since the lenses G1 to G3 do not rotate, even if the lens frame 20 is moved in the optical axis direction L, a subtle change in the captured image due to slight asymmetry that occurs in the manufacturing process of the lenses G1 to G3 occurs. Can be prevented.

The lens frame 20 is formed in a substantially cylindrical shape with resin, and as shown in FIGS. 1 to 4, the lenses G <b> 1 to G <b> 3 are held inside and slidable on the inner peripheral surface 12 b of the cylindrical portion 12. An outer peripheral surface 20a composed of a cylindrical surface to be fitted, and a plurality (three) of cam follower portions 21 that are formed to protrude at equal intervals in the circumferential direction of the outer peripheral surface 20a and engage with a cam portion 32 described later of the cam ring 30. Prepare.
The cam follower portion 21 includes two protruding pieces 21A and 21B that face each other with a predetermined gap in the optical axis direction L. The protruding pieces 21A and 21B are formed so as to be able to come into contact with a cam surface 32a of a cam portion 32 (to be described later) of the cam ring 30, and the opposing surface 21a is curved in a convex shape. By forming the opposing surface 21a to be curved in a convex shape, the opposing surface 21a can be stably brought into contact with a cam surface 32a of the cam portion 32 described later, and a smooth cam action can be obtained.
In addition, the cam follower portion 21 holds the cam portion 32 described later from both sides in the optical axis direction L by two projecting pieces 21A and 21B in order to maintain the engagement with the cam portion 32 described later in the optical axis direction L. Thereby, the cam follower part 21 will be in the state connected slidably with respect to the cam part 32 mentioned later.

The cam ring 30 is formed by pressing an annular metal plate. As shown in FIGS. 1 to 5, the cam ring 30 is formed integrally with the base portion 31, the base portion 31 and the cam follower portion 21. A cam portion 32 that engages and exerts a cam action in the optical axis direction L, and an operation portion that is integrally formed with the base portion 31 and rotates the cam ring 30 that protrudes toward the outside of the base portion 31. 33.
The base 31 and the inner peripheral surface 31a that is slidably fitted to the outer peripheral surface 12a of the cylindrical portion 12 define an arc-shaped notch 31b that is located behind the cam portion 32 in the optical axis direction L. Is formed. The cam ring 30 is rotatably supported by the cylindrical portion 12 by fitting an inner peripheral surface 31 a thereof to the outer peripheral surface 12 a of the cylindrical portion 12. Further, the rear surface 31 c of the base portion 31 in the optical axis direction L is slidably supported on the front surface 11 a of the base portion 11 of the fixed frame 10.

The cam portion 32 is formed in a leaf spring shape protruding in a cantilever shape with a predetermined inclination angle forward from the base portion 31 in the optical axis direction L, and is equally spaced in the circumferential direction of the cam ring 30 (the base portion 31). A plurality (three) are formed at the position. The cam portion 32 is formed in an arc shape having a curvature that substantially matches the outer peripheral surface 12 a of the cylindrical portion 12.
By forming the cam portion 32 in a leaf spring shape and a cantilever shape, an impact force larger than the force that moves the lens frame 20 in the optical axis direction L during normal operation (substantially in the optical axis direction L) is increased. When it acts on 20, it can be elastically deformed (flexible deformation) against this impact force. In addition, by forming the cam portion 32 in a leaf spring shape and a cantilever shape, it is possible to obtain elastic deformation with a relatively simple structure, and from the annular plate member provided with the operation portion, the cam can be formed by press working or the like. The part can be easily formed.
Further, the cam portion 32 has cam surfaces 32a and 32a that can come into contact with the two protruding pieces 21A and 21B on both surfaces in the optical axis direction L, and are slidably held by the protruding pieces 21A and 21B. ing. For this reason, the opposing surfaces 21a and 21a of the projecting pieces 21A and 21B abut against the corresponding cam surfaces 32a, respectively, so that the engagement between the cam portion 32 and the cam follower portion 21 is always maintained.

  In assembling the lens driving device, first, the inner peripheral surface 31 a of the cam ring 30 is fitted into the outer peripheral surface 12 a of the cylindrical portion 12 of the fixed frame 10. Next, the outer peripheral surface 20 a of the lens frame 20 is fitted into the inner peripheral surface 12 b of the cylindrical portion 12 while the cam follower portion 21 of the lens frame 20 is inserted into the guide hole 13 of the cylindrical portion 12. Next, while rotating the cam ring 30 in one direction, the cam portion 32 is inserted into the gap formed between the projecting pieces 21A and 21B from the tip side, and the cam follower portion 21 is slidably connected to the cam portion 32. Then, the lens frame 20 is brought into a state where it does not fall off from the cylindrical portion 12. Thereby, the assembly of the apparatus is completed.

Next, the operation of the lens driving device will be described with reference to FIGS.
As shown in FIG. 2, in a state where the lens frame 20 of the lens driving device is at the normal photographing position, the lens frame 20 is retracted rearward in the optical axis direction L, and the cam follower portion 21 is located at the base region of the cam portion 32. In contact. In order to move the lens frame 20 from this position to the close-up shooting position, the operation unit 33 of the cam ring 30 is operated and rotated in the R2 direction. When the cam ring 30 is rotated in the R2 direction, the lens frame 20 moves forward in the optical axis direction L according to the cam profile of the cam surface 32a of the cam portion 32 (the inclination angle of the cam portion 32) by the cam action of the cam portion 32. Then, the close-up photographing position as shown in FIG. 6 is reached. In order to move the lens frame 20 from the close-up shooting position to the normal shooting position, the cam ring 30 may be rotated in the R1 direction.

  When an impact is applied to the lens frame 20 due to the lens drive device or a portable information terminal equipped with the lens drive device falling or the like, the impact force applied to the lens frame 20 is transmitted to the cam portion 32 through the cam follower portion 21. The cam portion 32 absorbs or relaxes the impact force while elastically deforming (deflecting) upon receiving the impact force, and then elastically returns to a predetermined shape by the restoring force.

  As described above, according to the present embodiment, the cam portion 32 of the cam ring 30 has the function of absorbing or reducing the impact force as well as the cam function, thereby absorbing or reducing the impact force applied to the lens frame 20. Need not be provided separately, and the apparatus can be miniaturized and a structure resistant to impacts.

  Further, according to the present embodiment, the cam follower portion 21 sandwiches the cam portion 32 in the optical axis direction L, and the cam follower portion 21 is slidably connected to the cam portion 32, so that the forward movement direction and the backward movement direction are achieved. In both directions, a smooth cam action can be obtained, and a spring or the like for maintaining the engagement between the cam follower portion 21 and the cam portion 32 is not required, and the apparatus can be further miniaturized.

  In the above embodiment, the case where the cam portion 32 is formed integrally with the cam ring 30 has been described. However, the present invention is not limited to this, and the cam portion 32 is formed separately from the cam ring 30 and fastened with screws or the like. It is also possible to combine by means.

  In the above embodiment, the case where the cam follower portion 21 is slidably connected to the cam portion 32 in the optical axis direction L has been described. However, the present invention is not limited to this, and the lens frame 20 is not connected by a spring or the like. The cam follower portion 21 and the cam portion 32 are engaged with each other so that one projecting portion of the cam follower portion 21 that is biased toward the cam ring 30 and pushed by the biasing force is brought into contact with one cam surface facing the cam protrusion 30. It is also possible to make it the structure to maintain.

  In the above embodiment, the case where the cam portion 32 is formed in a cantilever shape has been described. However, the present invention is not limited to this, and as described above, the lens frame 20 is biased toward the cam ring 30 side. In this case, it is possible to have a structure of fixed beams with no open ends. Further, it is also possible to provide a structure that can prevent the cam portion 32 from being excessively deformed by providing a support protrusion or the like on the outer peripheral surface 12 a of the cylindrical portion 12 to support the cantilevered cam portion 32.

  In the above-described embodiment, the case where the cam portion 32 is formed in a leaf spring shape and can be elastically deformed has been described. A shape, for example, a round bar shape is also possible.

  Although the case where the cam ring 30 is formed by pressing an annular metal plate has been described in the above embodiment, the present invention is not limited to this, and the cam ring 30 may be formed by injection molding using a resin. Is possible.

  In the above-described embodiment, the case of the lens driving device for macro switching has been described. However, the present invention is not limited to this, and the lens driving device can be used for zooming or focusing.

  As described above, the lens driving device of the present invention is applied as a lens driving device for a digital camera unit mounted on a portable information terminal or the like that is required to be reduced in size and weight, such as a mobile phone and a portable personal computer. Needless to say, the present invention is useful in other lens optical systems as long as the lens needs to be driven.

It is a perspective view which shows the external appearance of the lens drive device which concerns on one Embodiment of this invention. It is a perspective view containing the cross section of the optical axis direction of the lens drive device in a normal imaging position. It is sectional drawing of the optical axis direction of a lens drive device. It is a disassembled perspective view of an apparatus. It is a perspective view of a cam ring. It is a perspective view including the cross section of the optical axis direction of the apparatus in a close-up photographing position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fixed frame 11 ... Base part 11a ... Front surface 12 ... Cylindrical part 12a ... Outer peripheral surface 12b ... Inner peripheral surface 13 ... Guide hole 20 ... Lens frame 20a ... Outer peripheral surface 21 ... Cam follower part 21A, 21B ... Projection piece (cam follower part)
21a ... Opposing surface 30 ... Cam ring 31 ... Base 31a ... Inner peripheral surface 31b ... Notch 31c ... Rear surface 32 ... Cam portion 32a ... Cam surface 33 ... Operation unit 100 ... CCD
101 ... IR filters G1, G2, G3 ... Lens L ... Optical axis direction

Claims (9)

A fixed frame having a cylindrical portion that extends in the optical axis direction, a lens frame that is supported movably in the optical axis direction inside the cylindrical portion and that holds the lens, and rotates outside the cylindrical portion A cam ring having a cam portion that is freely supported and engages with a cam follower portion formed on the lens frame and exerts a cam action in the optical axis direction,
The cam portion is formed to be elastically deformable in the optical axis direction.
A lens driving device. The cam follower portion is slidably connected to the cam portion so as to maintain engagement with the cam portion in the optical axis direction.
The lens driving device according to claim 1. The cam portion is formed integrally with the cam ring,
The lens driving device according to claim 1 or 2, wherein The cam portion is formed in a leaf spring shape,
The lens driving device according to claim 1, wherein the lens driving device is a lens driving device. The cam portion is formed in a cantilever shape,
The lens driving device according to claim 4. The cam follower portion is formed so as to slidably hold the cam portion in the optical axis direction.
The lens driving device according to claim 4 or 5, wherein The cam follower part is composed of two projecting pieces formed so as to be able to contact the cam surface of the cam part and to face each other in the optical axis direction,
The opposing surface of the protruding piece is curved in a convex shape,
The lens driving device according to claim 6. A plurality of the cam portions are formed at equally spaced positions in the circumferential direction of the cam ring.
The lens driving device according to claim 1, wherein: The cylindrical portion has a guide hole through which the cam follower portion is inserted to guide the lens frame so as to be movable in the optical axis direction.
The lens driving device according to claim 1, wherein the lens driving device is a lens driving device.

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