JP2007033957A - Lens drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize a lens drive device having a unit for exposure quantity adjustment. <P>SOLUTION: The lens drive device includes: a lens frame 20 holding a lens; a cam ring 30 that exerts a cam action to the lens frame, thereby moving the lens frame in the direction of an optical axis; a lens base 10 supporting the lens frame and cam ring; and a coil spring 50 exerting a pressing force to press the lens frame to the cam ring. The unit 100 for exposure quantity adjustment fixed to a lens base 10 and used to adjust a quantity of exposure is disposed in front of the lens frame 20. One end part 51 of the coil spring 50 is attached by being directly elastically deformed by the unit 100. This eliminates the need for a pressing member or the like specially provided to press the coil spring 50 and, therefore, reduces a dimension in the direction of the optical axis by that amount. Accordingly, the size, thickness and cost of the device can be reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lens driving device that reciprocates a lens frame holding a lens by a cam member that exerts a cam action in the optical axis direction, and in particular, includes an elastic member that presses the lens frame against the cam member and an exposure adjustment unit. The present invention relates to a lens driving device.

  As a conventional lens driving device, a cylindrical lens frame that holds a lens and is supported so as to be movable in the optical axis direction with respect to the fixed cylinder, and is sandwiched between a front end portion of the fixed cylinder and a flange portion of the lens frame. An annular cam member (adjustment ring) that exerts a cam action in the optical axis direction, a coil spring disposed in front of the lens frame to press the lens frame against the cam member, and a coil spring to hold the coil spring in a compressed state An annular pressing cover or the like that is disposed in front of and connected to a fixed cylinder is provided, and the cam member is rotated by an urging force of the coil spring while rotating the cam member to move the lens in the optical axis direction. What is moved to is known (for example, refer to Patent Document 1).

  As another conventional lens driving device, a cylindrical lens frame that holds a lens and is supported so as to be movable in the optical axis direction with respect to the cylindrical member, a front end portion of the cylindrical member, and a flange portion of the lens frame An annular cam ring that is sandwiched between the lens frame and exerts a cam action in the optical axis direction, a coil spring disposed in front of the lens frame to press the lens frame against the cam ring, and a coil spring to hold the coil spring in a compressed state An annular pressing member that is disposed in front of the cylindrical member and connected to the cylindrical member, and a diaphragm blade that is swingably supported by the lens frame in front of the pressing member to reduce the aperture diameter. The lens is moved in the optical axis direction by rotating the cam ring while maintaining the close contact state of the cam ring by the force, and the aperture is reduced by moving the aperture blade. Is known (e.g., see Patent Document 2).

  On the other hand, in portable information terminals such as cellular phones, PDAs, portable personal computers, etc., with the widespread use of models equipped with camera units, it is possible to shoot with higher image quality, and close-up photography with a movable lens (macro There is a need for a model capable of shooting) or zooming. Therefore, there is a demand for a mobile phone equipped with a lens driving device including an exposure amount adjustment unit (such as a shutter unit) that moves the lens in the optical axis direction and adjusts the exposure amount.

JP-A-10-170809 JP 2005-128356 A

Therefore, when an exposure amount adjustment unit such as a shutter unit is simply added to the conventional lens driving device, a dedicated part such as a pressing cover that presses the coil spring is used. As a result, the entire apparatus is increased in size and is difficult to be mounted on a small mobile phone or the like.
Also, if the distance in the optical axis direction from the exposure adjustment unit (the travel surface of the shutter blades) to the lens is wide, problems such as beam burrs will occur. To solve this problem, the opening of the exposure adjustment unit will be enlarged. As a result, the planar size of the device is increased, and it is difficult to mount the device on a small mobile phone or the like.

  The present invention has been made in view of the above-described prior art, and the object of the present invention is to reduce the number of parts and reduce the number of parts so as to be applied to a mobile camera mounted on a small mobile phone or the like. It is an object of the present invention to provide a lens driving device that can be reduced in cost, reduced in size, and reduced in thickness, can withstand an impact such as dropping, and can be driven smoothly to obtain a higher quality image.

The lens driving device of the present invention includes a lens frame that holds a lens, a cam member that moves the lens frame in the optical axis direction by applying a cam action to the lens frame, a lens base that supports the lens frame and the cam member, and a cam for the lens frame. An elastic member that exerts an urging force to press the member, and an exposure amount adjustment unit that is fixed to a lens base and adjusts an exposure amount is disposed in front of the lens frame, and the elasticity One end of the member is attached by being elastically deformed directly by the exposure adjustment unit.
According to this configuration, when the cam member is actuated to exert a cam action on the lens frame, the lens frame moves in the optical axis direction with the urging force of the elastic member acting. Thereby, close-up photography or zoom photography can be performed. In addition, since the exposure adjustment unit is provided, a high-quality and clear image can be taken by appropriately adjusting the exposure at the time of shooting.
Furthermore, since one end of the elastic member is directly held by the exposure adjustment unit, there is no need to use a dedicated pressing member or the like as in the prior art, the number of parts can be reduced, and the dimension in the optical axis direction can be reduced. It can be shortened, and the device can be reduced in size, thickness, and cost. Further, since the exposure adjustment unit is fixed to the lens base, it is possible to obtain a strength that can sufficiently withstand an impact such as dropping. Accordingly, it is possible to obtain a lens driving device suitable for a mobile camera mounted on a mobile phone or the like that is required to be downsized and that may drop.

In the above configuration, the exposure amount adjustment unit includes a unit base that defines an opening having a predetermined aperture, a blade member that moves between a position facing the opening on the unit base and a position outside the opening, and a blade member. A configuration including a drive source fixed to the unit base for driving can be employed.
According to this configuration, since the exposure adjustment unit includes the unit base, the blade member, and the drive source, it is possible to adjust the exposure quickly and appropriately at the time of shooting, and to capture a high-quality and clear image. It becomes possible.

In the above configuration, the elastic member may be a compression type coil spring, and the unit base may have a recess that receives one end of the coil spring.
According to this configuration, it is possible to assemble the coil spring accurately and easily simply by allowing one end of the coil spring to enter the recess of the unit base, improving the assemblability and hence the production of the device. Also improves.

In the above configuration, the elastic member is formed of a compression type coil spring, and the unit base has a protruding pressing portion that protrudes rearward in the optical axis direction and presses one end of the coil spring. be able to.
According to this configuration, various types of coil springs having different specifications can be attached by appropriately setting the protruding amount of the protruding pressing portion, and the compression allowance or attachment according to the specifications is ensured while ensuring the ease of assembly. You can gain power.

The said structure WHEREIN: The structure in which the hollow which receives the one end part of a coil spring is formed in the protruding press part is employable.
According to this configuration, when the coil spring is assembled in a compressed state, one end thereof is fitted into the depression of the projecting pressing portion, so that the shift can be prevented and the coil spring can be assembled at a predetermined position with high accuracy. .

In the above configuration, the elastic member may be formed of an elastic piece integrally formed with the lens frame so as to be elastically deformable in the optical axis direction.
According to this configuration, since the elastic member is an elastic piece integrally formed with the lens frame, the number of parts can be further reduced, and the assembly work can be facilitated by the reduced number of parts, further reducing the cost. can do.

In the above configuration, a configuration in which the lens base and the unit base are attached to each other so as to be integrated at a plurality of locations in the outer peripheral region can be adopted.
According to this configuration, the mechanical strength of the lens driving device to which the exposure adjustment unit is attached can be increased.

  According to the lens driving device having the above configuration, it is possible to reduce the number of parts, achieve cost reduction, downsizing, and thinning, and ensure sufficient strength to withstand impacts such as dropping. Since a clear image can be taken with high image quality, a lens driving device suitable for a mobile camera mounted on a small mobile phone or the like can be provided.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described with reference to the accompanying drawings.
1 to 5 show an embodiment of a lens driving device according to the present invention. FIG. 1 is a sectional view of the device, FIG. 2 is a front view of the device, and FIG. FIG. 4 is an exploded perspective view of a portion where the exposure adjustment unit is removed from the apparatus, and FIG. 5 is an exploded sectional view of the apparatus.

  As shown in FIGS. 1 to 5, this lens driving device includes a lens base 10 having a cylindrical portion 11 (having an axis) extending in the optical axis direction L and a housing portion 12 for housing an image pickup device E such as a CCD. A lens frame 20 accommodated in the cylindrical portion 11, a cam ring 30 as a cam member that exerts a cam action on the lens frame 20 in the optical axis direction L, a ring-shaped washer 40, and an outer peripheral surface of the cylindrical portion 11 are provided. The coil spring 50 as an elastic member that biases the lens frame 20 toward the cam ring 30, the exposure adjustment unit 100 fixed to the lens base 10 so as to press one end (front end) 51 of the coil spring 50, and the like. It has.

As shown in FIGS. 1 to 5, the lens base 10 includes a cylindrical portion 11 having an axis in the optical axis direction L, a storage portion 12 that stores the imaging element E behind the cylindrical portion 11, and a base region of the cylindrical portion 11. A formed support 13 for supporting the cam ring 30 in the optical axis direction L, a recess 14 for accommodating a drive source 130 (to be described later) of the exposure adjustment unit 100, a hole 15 for connecting the exposure adjustment unit 100 with a screw B, etc. It is formed by.
The cylindrical portion 11 is formed with three guide holes 11a that penetrate in the radial direction and extend in the optical axis direction L and open forward. The three guide holes 11a are formed at equiangular intervals (120 degrees) in the circumferential direction.

  As shown in FIGS. 1, 3, 4, and 5, the lens frame 20 includes a cylindrical portion 21 that holds the lens G therein, and three protrusions that protrude radially outward from the outer peripheral surface of the cylindrical portion 21. An opening restricting plate 23 is provided in front of the lens G. The opening restricting plate 23 defines a circular opening 23a having a predetermined diameter.

As shown in FIGS. 1, 3, and 5, the lens frame 20 is slidable in the optical axis direction L with its cylindrical portion 21 fitted (internally fitted) into the cylindrical portion 11 of the lens base 10. It is supported by. The three protrusions 22 are formed at equal angular intervals (120 degrees) in the circumferential direction and are inserted into the guide holes 11a of the cylindrical portion 11 so that there is no backlash in the circumferential direction and only in the optical axis direction L. It is guided so as to freely reciprocate.
In addition, the protrusion 22 is engaged with a cam surface 33 of a cam ring 30 described later on the rear side, and engaged with a rear end (other end) 52 of the coil spring 50 via a washer 40 on the front side. It has become.

  2, 3, and 5, the cam ring 30 is formed on the annular portion 31, the drive lever 32 projecting radially outward from the outer peripheral surface of the annular portion 31, and the front end surface of the annular portion 31. It is formed by three cam surfaces 33 or the like that exert a cam action on L. The cam ring 30 is rotatably supported by the annular portion 31 being fitted on the cylindrical portion 11 with the rear end surface of the annular portion 31 in contact with the support portion 13 of the lens base 10. Here, the three cam surfaces 33 are formed so as to receive the three protrusions 22 of the lens frame 20 and exert a cam action in the optical axis direction L, respectively.

  The washer 40 is formed into a thin plate and annular by punching a metal plate or the like. As shown in FIGS. 1, 3, and 4, the washer 40 is in the optical axis direction with respect to the cylindrical portion 11 of the lens base 10. The rear surface of the lens frame 20 is in contact with the protruding portion 22 of the lens frame 20 and the rear end portion (the other end portion) 52 of the coil spring 50 is received on the front surface.

As shown in FIGS. 1, 4, and 5, the coil spring 50 is a compression spring and is disposed so as to surround the outer peripheral surface of the cylindrical portion 11, and has a rear end portion (other end portion) 52. Abutting against the washer 40 and attached adjacent to the three projecting portions 22, the front end portion (one end portion) 51 is pressed by a unit base 110 of an exposure amount adjusting unit 100 described later to generate a predetermined urging force. It is built in a compressed state.
Accordingly, the coil spring 50 acts to urge the protruding portion 22 of the lens frame 20 toward the rear in the optical axis direction L so that the protruding portion 22 always contacts the cam surface 33.

  As shown in FIGS. 1, 2, and 5, the exposure adjustment unit 100 is swingable with respect to the unit base 110, which is fastened and fixed to the lens base 10 with screws B or the like. It is formed by two shutter blades 120 as supported blade members, a drive source 130 that opens and closes the shutter blades 120, a cover 140 that covers the shutter blades 120, an opening restriction plate 150 that restricts a predetermined aperture, and the like.

  As shown in FIGS. 1, 2, and 5, the unit base 110 includes an opening 111 having a predetermined diameter, and a recess 112 that receives a front end (one end) 51 of the coil spring 50 in the outer peripheral region of the opening 111. A mounting portion 113 for attaching the drive source 130, a support shaft 114 for swingably supporting the shutter blade 120, a screw hole 115 for fastening the lens base 10 with the screw B, a screw hole 116 for fastening the cover 140 with the screw B, and the like. Has been.

  As shown in FIGS. 1, 2, and 5, the two shutter blades 120 include a circular hole 121 through which the support shaft 114 passes, a long hole 122 through which a drive pin 131a of the rotor 131 described later passes, Due to the rotation of the rotor 131, the opening 111 of the unit base 110, the opening 151 of the opening regulating plate 150 described later, the position facing the opening 141 of the cover 140 described later, and the position deviated from the openings 111, 151, 141 are located. In other words, the amount of exposure that passes through the opening restricting plate 150 by opening and closing the opening 151 is adjusted.

  The drive source 130 is a moving magnet type motor, and as shown in FIGS. 1, 2, and 5, a rotor 131 having a drive pin 131a and rotating within a predetermined angle range, an excitation coil 132, a magnetic path, and the like. Are formed by a steel yoke 134 for adjusting a magnetic attractive force generated between each of the cylindrical yoke 133 and the magnetic poles of the rotor 131.

The cover 140 forms a moving space of the shutter blade 120 in cooperation with the unit base 110, and defines an opening 141 having a predetermined diameter.
The opening restriction plate 150 is joined to the unit base 110 behind the shutter blade 120 and defines an opening 151 having a predetermined diameter.

  As described above, since the exposure adjustment unit 100 has a shutter function, it is possible to appropriately perform a shutter operation at the time of photographing, and it is possible to photograph a clear image with high image quality.

Next, the assembly work of this apparatus will be described with reference to FIGS.
First, the cam ring 30, the lens frame 20, and the washer 40 are assembled to the lens base 10 in the order shown in FIG.
Next, the opening regulating plate 150, the shutter blade 120, the drive source 130, the cover 140, and the like are assembled to the unit base 110 to form the exposure amount adjustment unit 100 in which the shutter blade 120 is driven to open and close.

Then, as shown in FIG. 5, the lens drive unit U and the exposure amount adjustment unit 100 are opposed to each other, and a coil spring 50 is disposed between the lens drive unit U and the exposure amount adjustment unit 100. The (other end) 52 is brought into contact with the washer 40.
Subsequently, in a state where the coil spring 50 is held by the cylindrical portion 11, the exposure amount adjustment unit 100 is brought close to the front end portion (one end portion) 51 of the coil spring 50 so as to enter the concave portion 112 of the unit base 110. Then, the front end portion (one end portion) 51 is pressed and compressed while being joined to the lens base 10.

Then, the unit base 110 is fastened to the lens base 10 with a plurality of screws B, and a plurality of locations in the outer peripheral area are firmly fixed (attached). Thereby, as shown in FIG. 1, the assembly | attachment of an apparatus is completed.
Here, the coil spring 50 can be assembled accurately and easily only by allowing the front end portion (one end portion) 51 of the coil spring 50 to enter the recess 112 of the unit base 110, so that the assembling property is improved. Therefore, the productivity of the apparatus is also improved.

As described above, since the front end portion (one end portion) 51 of the coil spring 50 is directly held by the unit base 110 of the exposure amount adjustment unit 100, it is necessary to employ a conventional dedicated pressing member or the like. Absent. Therefore, the number of parts can be reduced, the dimension in the optical axis direction L can be shortened, and the apparatus can be reduced in size, thickness, and cost.
Further, since the exposure adjustment unit 100 is firmly fixed to the lens base 10, it is possible to obtain a strength that can sufficiently withstand an impact such as dropping. Accordingly, it is possible to obtain a lens driving device suitable for a mobile camera mounted on a mobile phone or the like that is required to be downsized and that may drop.

  Next, the operation of this apparatus will be briefly described. First, when the cam ring 30 is located at the counterclockwise rotation end when viewed from the front, the lens frame 20 (lens G) is retracted in the optical axis direction L. (Position approaching the image sensor E). In this state, since a subject that is several meters away is in focus, normal shooting is possible.

  On the other hand, when a clockwise driving force is exerted on the drive lever 32 and the cam ring 30 rotates clockwise and moves to the rotating end, the lens frame 20 (lens G) moves forward by a predetermined amount in the optical axis direction L. It is in the extended position (position away from the image sensor E). In this state, for example, macro photography (proximity photography) is possible because a close subject is in focus.

6 and 7 show another embodiment of the lens driving device according to the present invention. The same reference numerals are given to the same components as those of the above-described embodiment, and the description thereof will be omitted.
That is, in the lens driving device in this embodiment, as shown in FIG. 7, the unit base 110 protrudes rearward in the optical axis direction L and presses the front end portion (one end portion) 51 of the coil spring 50. A protruding pressing portion 112 'is formed.
The protruding pressing portion 112 ′ is formed in an annular shape along the coil spring 50, and a recess 112 a ′ for receiving the front end portion (one end portion) 51 of the coil spring 50 is formed on the end surface thereof.

Therefore, if the protrusion amount of the projecting pressing portion 112 ′ is set to a desired length in advance, various coil springs according to the specifications can be attached, and the ease of assembly can be ensured while complying with the specifications. Compression allowance or urging force can be obtained.
Further, when the coil spring 50 is assembled in a compressed state, the front end portion (one end portion) 51 is fitted into the recess 112a ′ of the projecting pressing portion 112 ′, so that the shift can be prevented and the coil spring 50 is placed at a predetermined position. Can be assembled with accuracy.

FIG. 8 shows still another embodiment of the lens driving device according to the present invention. The same components as those in the embodiments shown in FIG. 6 and FIG. Omitted.
That is, in the lens driving device in this embodiment, as shown in FIG. 8, an elastic piece 24 ′ as an elastic member is integrally formed with the lens frame 20 ′ so as to be elastically deformable in the optical axis direction L. Yes.

Three elastic pieces 24 ′ are provided at equal angular intervals in the outer peripheral direction of the cylindrical portion 21 of the lens frame 20 ′, and are elastically deformed by being pressed by the projecting pressing portion 112 ′ of the unit base 110. A biasing force is exerted to press the lens frame 20 ′ (projecting portion 22) against the cam surface 33 of the cam ring 30.
As described above, since the elastic member that presses the lens frame 20 ′ against the cam ring 30 is the elastic piece 24 ′ formed integrally with the lens frame 20 ′, the number of parts can be further reduced as compared with the above-described embodiment. As a result, the assembling work becomes easier as the number of parts is reduced, and the cost can be further reduced.

In the above-described embodiment, the cam ring 30 externally fitted to the cylindrical portion 11 is shown as the cam member. However, the cam ring 30 is not limited to this, and is not limited to this. The structure of the present invention may be employed in a structure including a cam member fixed so as not to rotate and a lens frame supported so as to be rotatable as long as a relative rotation operation can be obtained. .
In the above-described embodiment, the cam ring 30 that is manually rotated is shown as the cam member. However, the configuration of the present invention may be employed in a configuration that includes a cam ring that is driven by an electromagnetic drive source or the like.
In the above-described embodiment, the configuration in which the lens base 10 and the unit base 110 are coupled in advance is shown. However, the lens base and the unit base mounting frame are provided in the device in which the lens driving device is incorporated, and each mounting frame is provided. On the other hand, a lens base and a unit base may be attached to assemble the lens driving device.
In the above-described embodiment, the shutter device including the shutter blade 120 that opens and closes the openings 141 and 151 is shown as the exposure adjustment unit 100. However, the present invention is not limited to this, and the openings 141 and 151 are set to a predetermined size. You may employ | adopt the diaphragm | throttle device provided with the aperture blade which squeezes to an aperture, or the ND filter apparatus provided with the ND filter blade | wing.

  As described above, the lens driving device of the present invention has a simplified structure, can achieve a reduction in size of the device and a simplified structure, can withstand impacts such as dropping, and can be driven smoothly. In addition, since it is possible to shoot a higher quality image, it can be applied to a mobile camera mounted on a small mobile phone, a PDA, a portable personal computer, or the like, as well as other lens optical systems. It is also useful as a lens driving device.

It is sectional drawing which shows one Embodiment of the lens drive device which concerns on this invention. It is the front view which abbreviate | omitted a part of lens drive device shown in FIG. It is the front view which omitted the exposure amount adjustment unit of the lens drive device shown in FIG. It is a disassembled perspective view which shows the lens drive unit of the lens drive device shown in FIG. FIG. 2 is an exploded view of the lens driving device shown in FIG. 1 disassembled into a lens driving unit, a coil spring, and an exposure adjustment unit. It is a front view which shows other embodiment of the lens drive device which concerns on this invention. It is a side view of the lens drive device shown in FIG. It is a side view which shows other embodiment of the lens drive device which concerns on this invention.

Explanation of symbols

L Optical axis direction G Lens E Image sensor U Lens drive unit 10 Lens base 11 Cylindrical portion 11a Guide hole 12 Housing portion 13 Supporting portion 14 Recess 15 Hole 20, 20 'Lens frame 21 Cylindrical portion 22 Protruding portion 23 Opening restricting plate 23a Opening Part 24 'elastic piece (elastic member)
30 Cam ring (cam member)
31 annular part 32 drive lever 33 cam surface 40 washer 50 coil spring (elastic member)
51 Front end (one end)
52 Rear end (other end)
DESCRIPTION OF SYMBOLS 100 Exposure amount adjustment unit 110 Unit base 111 Opening part 112 Recessed part 112 'Protruding press part 112a' Depression 115,116 Screw hole 120 Shutter blade (blade member)
130 Drive source 131 Rotor 131a Drive pin 132 Excitation coil 133 Yoke 140 Cover 141 Opening 150 Opening restricting plate 151 Opening

Claims (7)

A lens frame that holds the lens, a cam member that exerts a cam action on the lens frame to move the lens frame in the optical axis direction, a lens base that supports the lens frame and the cam member, and presses the lens frame against the cam member An elastic member that exerts an urging force,
In front of the lens frame, an exposure amount adjustment unit that is fixed to the lens base and adjusts the exposure amount is disposed,
One end of the elastic member is directly elastically deformed and attached by the exposure amount adjustment unit.
A lens driving device. The exposure amount adjustment unit includes a unit base that defines an opening having a predetermined aperture, a blade member that moves between a position facing the opening and a position outside the opening on the unit base, and the blade member A drive source fixed to the unit base to drive
The lens driving device according to claim 1. The elastic member is a compression type coil spring,
The unit base has a recess for receiving one end of the coil spring.
The lens driving device according to claim 2. The elastic member is a compression type coil spring,
The unit base has a protruding pressing part that protrudes toward the rear in the optical axis direction and presses one end of the coil spring.
The lens driving device according to claim 2. The projecting pressing part has a recess for receiving one end of the coil spring.
The lens driving device according to claim 4. The elastic member comprises an elastic piece integrally formed with the lens frame so as to be elastically deformable in the optical axis direction.
The lens driving device according to claim 1 or 2, wherein The lens base and the unit base are attached to each other so as to be integrated at a plurality of locations in the outer peripheral region.
The lens driving device according to claim 2, wherein the lens driving device is a lens driving device.

Images