JP4679082B2 - Lens drive device - Google Patents

Description

  The present invention relates to a lens driving device applied to a digital camera mounted on a mobile phone, a portable personal computer, etc., and more particularly to a lens driving device having an autofocus function or a zoom function.

  As a conventional lens driving device applied to a digital camera or the like, a base for fixing a CCD or the like, a cylindrical fixed cylinder fixed to the base, a cylindrical cam cylinder rotatably disposed inside the fixed cylinder, A lens barrel that is disposed inside the cam barrel so as to reciprocate in the optical axis direction and holds a lens, and a motor that drives the cam barrel. When the cam barrel is rotated by the rotation of the motor, the cam groove is a follower pin of the lens barrel. It is known that focusing or zooming is performed by moving the lens tube in the optical axis direction by exerting a cam action (see, for example, Patent Document 1 and Patent Document 2).

JP 2002-286993 A JP 2003-057705 A

By the way, the conventional lens driving device is structurally complicated, has a relatively long dimension in the optical axis direction, and is large as a whole device. It is difficult to mount on a small portable information terminal such as the above.
Therefore, in order to apply a lens driving device that performs focusing or zooming electrically in a digital camera (mobile camera) mounted on a mobile phone or the like, it is necessary to reduce the size and thickness of the device.

  Further, in the conventional lens driving device, since the motor is fixed only by the flange portion formed on one end side, there is a possibility that the motor is dropped or damaged due to an impact caused by dropping of the camera or the like. Therefore, when mounted on a mobile phone or the like, it is necessary to improve impact resistance and functional reliability while reducing the size and thickness.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a small portable information terminal such as a cellular phone or a portable personal computer having an electric focus function or zoom function. An object of the present invention is to provide a lens driving device capable of improving impact resistance and functional reliability while reducing the weight, size, thickness, etc. so that it can be mounted.

The lens driving device of the present invention includes a base having a cylindrical portion that extends in the optical axis direction, a lens frame that holds the lens and is supported so as to reciprocate in the optical axis direction in the cylindrical portion, A driving mechanism that moves in the axial direction; a motor that is fixed to the base to exert a driving force on the driving mechanism; and a cover that has a hole through which the lens frame is inserted and is fixed to the base . A cam ring having a cam portion that is rotatably supported by the cylindrical portion and is rotationally driven by a motor and exerts a cam action on the lens frame in the optical axis direction, and a cylindrical shape for biasing the lens frame toward the cam ring includes a compression coil spring disposed around the section, the motor is arranged so that its rotation axis is the optical axis direction substantially perpendicular, said cover, a cam ring, a compression coil spring,及The motor and the base cooperate to cover from the front side in the optical axis direction are formed so as to hold surrounds the motor from the outside, is characterized in that.
According to this configuration, when the motor is rotated from the predetermined rest position, the cam ring is rotated, the cam portion cams the lens frame, and the lens frame (lens) is urged by the compression coil spring. While being moved in the optical axis direction, focusing or zooming is performed. Thus, since the drive mechanism has a simple configuration, the apparatus is simplified, and the apparatus can be reduced in thickness, size, cost, and the like.
In addition, since the cam ring, compression coil spring, and motor are covered with a single cover, the number of parts can be reduced compared with the case of providing a cover that covers each cover individually, thus simplifying assembly and reducing costs. can do. Furthermore , since the motor is placed and fixed on the base so that it has a rotation axis in a direction substantially perpendicular to the optical axis direction, and is held and surrounded by a cover from the outside, the device can be made thinner and smaller. In addition, the motor can be firmly fixed. Therefore, it can be easily mounted on a mobile phone or the like, and the impact resistance against dropping or the like is increased, and the functional reliability is improved.

In the above configuration, the drive mechanism further includes a torsion coil spring for rotation urging mosquitoes Muringu in one direction, it is possible to adopt a configuration.
According to this configuration, (without backlash or the like) backlash of the cam ring is prevented by a coil spring which Ri twisted, it is possible to perform Yes zooming in focusing have even from the angular position of the displacement with high accuracy.

In the above configuration, the torsion coil spring may be configured to be arranged in an annular groove formed on the front surface of the base or formed to open toward the inner peripheral side of the cam ring.
According to this configuration, the torsion coil spring is arranged in the annular groove, so that the space is effectively used, the device is reduced in size and thickness by consolidating the parts, and the torsion coil spring is dropped off. Can be prevented.

In the above configuration, the motor includes a case that supports the rotating shaft to which the drive gear is fixed, a flange portion that is integrally formed with one end portion of the case and that can be fastened to the base, and that is integrally formed with the other end portion of the case. A configuration including a fitting portion that is formed and can be fitted to the base can be employed.
According to this configuration, since the motor is fixed to the base via the flange portion formed at one end portion of the case and the fitting portion formed at the other end portion, the shock resistance against dropping or the like is further increased. As a result, the desired drive function can be obtained with certainty.

The said structure WHEREIN: The structure currently formed so that a cover may press and hold | maintain a compression coil spring is employable.
According to this configuration, since the cover serves as a press plate that holds the compression coil spring in a pressed state, the number of parts can be reduced as compared with the case where a press plate dedicated to the press is provided separately. Simplification of assembly work and cost reduction can be achieved.

In the above-described configuration, a configuration can be adopted in which the cylindrical portion has an outer peripheral surface that rotatably supports the cam ring, and the base has a restriction piece that restricts the cam ring from moving in the optical axis direction. .
According to this configuration, the cam ring is rotatably fitted on the outer peripheral surface of the cylindrical portion, and the movement in the optical axis direction is restricted by the base restricting piece, so that there is no backlash in the optical axis direction. Therefore, focusing or zooming can be performed with high accuracy.

  The lens driving device having the above configuration is provided with an electric focus function or zoom function, and can achieve weight reduction, downsizing, thinning, and the like, and can improve impact resistance and functional reliability. It can be easily mounted on a small portable information terminal such as a cellular phone or a portable personal computer.

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 an external perspective view of the device, FIG. 2 is an exploded perspective view of the device, and FIG. 3 is a plan view of the device. 4 and 5 are side views of the apparatus, and FIG. 6 is a cross-sectional view of the apparatus.

As shown in FIGS. 1 to 5, the lens driving device has a substantially rectangular outline with a dimension in the optical axis direction L of 10 mm or less and a side of 20 mm or less. A driving force is applied to the base 10 having the extending cylindrical portion 11, the lens frame 20 accommodated in the cylindrical portion 11, the annular cam ring 30 provided to be rotatable around the cylindrical portion 11, and the cam ring 30. A motor 40, a torsion coil spring 50 that urges the cam ring 30 to rotate in one direction, a bearing ring 60, a compression coil spring 70 that presses the lens frame 20 rearward in the optical axis direction L, and a cover that is fixed to the base 10. 80, a sensor 90, and the like.
The cam ring 30, the compression coil spring 70, and the torsion coil spring 50 constitute a drive mechanism that moves the lens frame 20 in the optical axis direction L.

The base 10 includes a cylindrical portion 11, a substantially rectangular recess 12 formed at the rear of the cylindrical portion 11, an end surface 13 and a fitting hole 14 for fixing the motor 60, and a front surface 10 a of a root area of the cylindrical portion 11. An annular groove 15 formed on the cam ring 30, a seating surface 16 of the cam ring 30, three restricting pieces 17 for restricting the cam ring 30 from moving in the optical axis direction L, three boss portions 18 for fastening the cover 80, and the cam ring 30. Are provided with a stopper pin 19 that prevents the cover from falling off, a projection 10b for positioning the cover 80, a projection 10c for positioning the motor 40, and the like.
In the recess 12, a glass filter 100 and a CCD 110 as an image sensor are arranged.

  The cylindrical portion 11 has a cylindrical shape that defines the outer peripheral surface 11a. The cylindrical portion 11 extends in the radial direction, extends in the optical axis direction L, and opens to the front side F. The cylindrical portion 11 protrudes from the opening end. The positioning protrusion 11c is formed. The three guide holes 11b are formed at equal intervals (120 degrees) in the circumferential direction.

As shown in FIGS. 2, 3, and 6, the lens frame 20 includes a cylindrical portion 21 that holds the lens G therein, three protruding portions 22 that protrude radially outward from the outer peripheral surface of the cylindrical portion 21, and the like. An aperture plate 23 having a predetermined aperture diameter is provided in front of the lens G.
As shown in FIG. 6, the cylindrical portion 21 is fitted (internally fitted) on the inner peripheral surface of the cylindrical portion 11 and is supported so as to be slidable in the optical axis direction L.
The three protrusions 22 are formed at equiangular intervals (120 degrees) in the circumferential direction, are inserted through the guide holes 11b of the cylindrical portion 11, and reciprocate only in the optical axis direction L without any backlash in the circumferential direction. Guided freely. Further, each of the protrusions 22 has a side surface on the rear side R engaged with a cam surface 34 of the cam ring 30 described later, and a side surface on the front side F is engaged with one end portion of the compression coil spring 70 via the seating surface ring 60. It comes to match.

  As shown in FIGS. 1, 2, 4 to 6, the cam ring 30 includes an annular portion 31 and an annular portion 31 that are rotatably (slidably) fitted to the outer peripheral surface 11 a of the cylindrical portion 11. A gear part (worm wheel) 32, three hooking pieces 33, and three cam surfaces 34 as cam parts formed on the front surface of the annular part 31. A detected piece 35 formed so as to protrude radially outward from the annular portion 31 is provided.

In the cam ring 30, the annular portion 31 is connected to the outer peripheral surface 11 a of the cylindrical portion 11 and the base in a state where the hooking piece 33 is hooked on the restriction piece 17 of the base 10 and the movement in the optical axis direction L is restricted. 10 slidably supported on the seating surface 16, and is rotatable around the optical axis within a predetermined angle range.
The three cam surfaces 34 receive the three protrusions 22 of the lens frame 20 and exert a cam action in the optical axis direction L. The gear portion 32 meshes with a worm 43 of a motor 40 to be described later. When the motor 40 rotates, the cam ring 30 is rotationally driven via the worm 43 and the gear portion 32, and the cam surface 34 and the protruding portion. The lens frame 20 can be moved to a desired position in the optical axis direction L via 22.

As shown in FIGS. 2 and 6, the torsion coil spring 50 is disposed near the inner periphery of the cam ring 30 and in the annular groove 15 of the base 10, and is shown in FIGS. 1, 2, 3, and 6. Thus, one end 51 is hooked on the cam ring 30 and the other end 52 is hooked on the boss portion 18 (the root portion) of the base 10 to urge the cam ring 30 to rotate clockwise (one direction). Yes.
Thus, since the torsion coil spring 50 is disposed near the inner periphery of the cam ring 30 and in the annular groove 15 of the base 10, the space is effectively used, and the apparatus is downsized by consolidating parts. Thinning is achieved, and the torsion coil spring 50 can be prevented from falling off.

The motor 40 is a step motor, and as shown in FIGS. 1 to 3 and 6, a rotating shaft 41, a case 42 that rotatably supports the rotating shaft 41 and surrounds a coil, a permanent magnet, and the like, a rotating shaft It is formed by a worm 43 or the like as a drive gear fixed to 41.
The case 42 is formed in a cylindrical shape, and at one end thereof, a flange portion 42a that is integrally formed in a substantially rectangular flat plate shape, and a fitting portion 42b that is integrally formed in a cylindrical shape at the other end portion, The terminal part 42c etc. which protruded and formed from the outer peripheral surface are provided.
The flange portion 42a has a cylindrical convex portion 42a ′, an insertion hole 42a ″ for the screw B, and a positioning hole 42a ″ for fitting the protrusion 10c.
The motor 40 is not limited to a step motor, and a DC motor may be employed.

  As shown in FIGS. 1 and 2, the motor 40 is oriented such that the rotation shaft 41 (the axis S thereof) is substantially perpendicular to the optical axis direction L, and the fitting portion 42 b is fitted in the fitting hole 14. The flange portion 42a is joined to the end face 13 and fastened by the screw B while the protrusion 10c is fitted into the hole 42a ″. That is, since the motor 40 is disposed along the base 10 in the longitudinal direction (the direction of the axis S), the apparatus can be thinned in the optical axis direction L, and the longitudinal direction (the direction of the axis S). ) Are firmly fixed to the base 10 at two locations apart from each other, so that the impact resistance against dropping or the like is enhanced, and therefore, the positional deviation or dropping off from the mounting position of the base 10 is prevented. The drive function can be obtained reliably.

As shown in FIGS. 2, 4 to 6, the compression spring 70 is attached to the outer peripheral surface of the tubular portion 11 so as to be positioned on the front side of the protruding portion 22 with the seat ring 60 interposed therebetween. It is pressed by 80 and held in a compressed state so as to generate a predetermined urging force.
Therefore, the compression spring 70 exerts an urging force so as to urge the protruding portion 22 of the lens frame 20 toward the rear side R in the optical axis direction L so as to always contact the cam surface 34.

As shown in FIGS. 1 to 3, the cover 80 is formed of a sheet metal material or a resin plate having a high bending strength, and has a circular hole 81 through which the lens frame 20 is inserted, a notch 82 for positioning, and a hole. 83, a rectangular opening 84 for exposing the terminal portion 42c of the motor 40, a holding piece 85 having a fitting hole 85a for contacting the outer side of the flange portion 42a of the motor 40 and preventing falling off, and insertion of the screw B A hole 86 and the like are provided.
The cover 80 has the torsion coil spring 50, the cam ring 30, the bearing ring 60, the compression coil spring 70, the motor 40, etc. attached to the base 10, and then the projections 11c and 10b are fitted into the notches 82 and the holes 83. In addition, it is fastened to the boss portion 18 of the base 10 by the screw B while fitting the convex portion 42a ′ into the fitting hole 85a.

  Here, the cover 80 is formed so as to cover the compression coil spring 70, the cam ring 30, the motor 40, and the like from the front side in the optical axis direction L, except for the lens frame 20 and the terminal portion 42 c of the motor 40. The coil spring 70 is pressed and held, and the motor 40 is surrounded and held in cooperation with the base 10.

That is, since the case 42 is not only fixed to the base 10 but also covered and held from the outside by the holding piece 85 of the cover 80, the motor 40 is attached more firmly and is resistant to dropping and the like. Improves impact resistance and improves functional reliability.
In addition, the number of parts can be reduced, the assembly work can be simplified, the cost can be reduced, and the like, compared with the case where a presser plate that holds the compression coil spring 70 in a pressed state is provided separately. 30, the compression coil spring 70, and the motor 40 are covered with a single cover 80, so that the number of parts can be reduced as compared with the case where covers are individually covered, thus simplifying assembly work and reducing costs. Can be achieved.

  The sensor 90 is an optical sensor that detects the detected piece 35 of the cam ring 30 and detects a state in which the lens frame 20 is in the retracted position where the lens frame 20 is retracted. The sensor 90 is fixed on the base 10 via an attachment piece formed to protrude from the base 10.

Next, the procedure for assembling this apparatus will be described.
First, the fitting portion 42b is fitted into the fitting hole 14, and the flange portion 42a is brought into contact with the end face 13, and the motor 40 is assembled to the base 10 and fastened with the screw B.
Subsequently, the torsion coil spring 50 is disposed in the annular groove 15 of the base 10, and the cam ring 30 is externally fitted to the cylindrical portion 11 (the outer peripheral surface 11a) from above (the front side in the optical axis direction L). The stop piece 33 is engaged with the restriction piece 17 of the base 10.

  Then, one end 51 of the torsion coil spring 50 is hooked on the cam ring 30 and the other end 52 is hooked on the base 10. Further, the stopper pin 19 is fitted to the base 10 so that the detected piece 35 comes into contact with the stopper pin 19 to restrict further rotation so that the cam ring 30 does not fall out of the cylindrical portion 11.

  Subsequently, the lens frame 20 to which the lens G is assembled is slidably fitted inside the cylindrical portion 11, and the protruding portion 22 is slidably fitted to the guide 11b. Then, the seat ring 60 is attached around the cylindrical portion 11 and brought into contact with the protruding portion 22. Further, the compression coil spring 70 is attached around the cylindrical portion 11 and placed on the seating ring 60.

Subsequently, while pressing the compression coil spring 70, the holding piece 85 is brought into contact with the flange portion 42 a of the motor 40 from the outside, assembled to the base 10, and fastened with the screw B. Thereby, the assembly of the apparatus is completed.
As described above, since the apparatus is composed of a small number of parts, the assembling work can be easily performed and the productivity can be improved. In particular, since one cover 80 serves as a holding plate that presses the compression coil spring 70 and a holding plate that prevents the motor 40 from falling off, the assembling work can be simplified as compared with the case where the cover 80 is constituted by separate parts.

FIG. 7 shows an embodiment in which the lens driving device M is mounted on a mobile phone. That is, as shown in FIG. 7, the mobile phone 200 includes a main body 201 in which various operation buttons 201 a are arranged and various electronic components are arranged therein, and is connected to the main body 201 so as to be openable and closable. Are formed by a cover body 202 provided with a monitor 202a for displaying the image, a camera unit 203 disposed on the cover body 202, and the like. The lens driving device M of the present invention is applied to the camera unit 203.
As described above, the lens driving device M of the present invention can be easily mounted in the mobile phone 200 that is required to be thin, small, and light.

Next, an operation when the lens driving device is mounted on the mobile phone 200 will be described. First, in the rest position, the lens frame 20 is in a retracted state.
When the operator wants to take a picture with the camera unit 203 in the rest state, the motor 40 is rotated by operating a predetermined operation button 201a for shifting to the shooting mode, and the biasing force of the torsion coil spring 50 is used. The cam ring 30 rotates while being loosened.

Then, while being urged by the compression coil spring 70, the cam surface 34 exerts a cam action in the optical axis direction L with respect to the protrusion 22 of the lens frame 20, and the lens frame (lens) in the retracted state (rest position). G) 20 is appropriately moved forward in the optical axis direction L, and focusing for automatically focusing is performed. When this focusing is completed, the operator can shoot the subject.
This focusing can be performed not only by rotating the motor 40 in one direction but also by rotating it in the other direction because the cam ring 30 is loosely moved by the torsion coil spring 50.

  When shooting is finished and the operator presses the operation button 201a for shifting to the non-shooting mode, the motor 40 rotates in the other direction, the cam ring 30 returns to the original rest position, and the lens frame 20 Returns to the retracted position.

  FIGS. 8 and 9 are an exploded perspective view showing another embodiment of the lens driving device according to the present invention and a plan view with the cover removed, and are the same as those in the previous embodiment except that the shape of the base and the cover are changed. Are the same. Therefore, the same reference numerals are given to the same components as those of the above-described embodiment, and the description thereof is omitted.

That is, as shown in FIGS. 8 and 9, the base 10 ′ is formed at a position facing the end face 13 in the axis S direction of the motor 40 and the boss portion 18 formed in the vicinity of the case 42 of the motor 40 being accommodated. Another end face 13 'and the like.
Further, the cover 80 ′ includes three bent pieces 81 a formed at the edge of the hole 81 through which the lens frame 20 is inserted, an insertion hole 86 of the screw B formed in the vicinity where the case 42 of the motor 40 is accommodated, The holding piece 85 has an insertion hole 85b for the screw B, an attachment piece 87 that is bent to face the holding piece 85 so as to be in contact with the end surface 13 ', and has an insertion hole 87a for the screw B.

That is, in this device, the cover 80 ′ is fastened to the base 10 ′ (boss portion 18) in the vicinity of the motor 40 (case 42), and the holding piece 85 is brought into contact with the flange portion 42 a of the motor 40. At the same time, it is fastened with the screw B together with the flange portion 42 a, and the attachment piece 87 is brought into contact with the end face 13 ′ and fastened with the screw B.
In addition, the bent piece 81a of the cover 80 'is externally fitted to the outer peripheral surface 11a of the cylindrical portion 11, so that it is reliably prevented from being lifted forward in the optical axis direction L.

  Therefore, the cover 80 'is securely fixed to the base 10', and the motor 40 is more firmly fixed to the base 10 '. As a result, impact resistance against dropping or the like is increased, and functional reliability is further improved.

In the above-described embodiment, the configuration in which one lens frame 20 is moved by the cam ring 30 to perform focusing has been described. However, the present invention is applied to a configuration in which zooming is performed by relatively moving a plurality of lens frames. It may be adopted.
In the above embodiment, the case where the step motor is adopted as the drive source has been described. However, the present invention is not limited to this, and a case where a detection means (for example, an optical sensor) for detecting the rotation angle range of the cam ring 30 is provided. Can employ a DC motor as a drive source.

  As described above, the lens driving device of the present invention can perform focusing (or zooming) while achieving simplification, miniaturization, thinning, etc. of the structure, and thus can be achieved in small-sized mobile phones, portable personal computers, and the like. The present invention is useful not only for portable information terminals but also for other information terminals equipped with a digital camera.

1 is an external perspective view showing an embodiment of a lens driving device according to the present invention. It is a disassembled perspective view of the lens drive device shown in FIG. It is a top view of the lens drive device shown in FIG. It is a side view of the lens drive device shown in FIG. It is a side view of the lens drive device shown in FIG. It is sectional drawing which shows the inside of the lens drive device shown in FIG. It is an external appearance perspective view which shows embodiment which mounted the lens drive device of this invention in the mobile telephone. It is a disassembled perspective view which shows other embodiment of the lens drive device which concerns on this invention. It is a top view which shows the state which removed the cover of the lens drive device shown in FIG.

Explanation of symbols

10, 10 'Base 10a Front surface 10b, 10c Protrusion 11 Cylindrical portion 11a Outer peripheral surface 11b Guide hole 11c Protrusion 12 Recess 13, 13' End surface 14 Fitting hole 15 Annular groove 16 Seat surface 17 Restriction piece 18 Boss portion 19 Stopper pin 20 Lens frame 21 Cylindrical portion 22 Protruding portion 23 Aperture plate G Lens 30 Cam ring (drive mechanism)
31 annular part 32 gear part 33 latching piece 34 cam surface (cam part)
35 Detected piece 40 Motor 41 Rotating shaft 42 Case 42a Flange portion 42a 'Convex portion 42a''Insertion hole 42a''hole 42b Fitting portion 42c Terminal portion 43 Worm (drive gear)
50 Torsion coil spring (drive mechanism)
60 Seat ring 70 Compression coil spring (drive mechanism)
80, 80 'cover 81 hole 81a bent piece 82 notch 83 hole 84 opening 85 holding piece 85a fitting hole 85b insertion hole 86 insertion hole 87 attachment piece 87a insertion hole 90 sensor 110 CCD
200 Mobile phone 203 Camera unit M Lens drive device L Optical axis direction S Axis of rotation axis B Screw

Claims (6)

A base having a cylindrical portion extending in the optical axis direction, a lens frame that holds the lens and is reciprocally supported in the optical axis direction in the cylindrical portion, and a drive that moves the lens frame in the optical axis direction A mechanism, a motor fixed to the base to exert a driving force on the driving mechanism, and a cover having a hole through which the lens frame is inserted and fixed to the base,
The drive mechanism is rotatably supported by the cylindrical portion and is rotationally driven by the motor to have a cam ring having a cam portion that exerts a cam action in the optical axis direction on the lens frame; and A compression coil spring disposed around the tubular portion to bias toward the cam ring;
The motor is arranged such that its rotation axis is substantially perpendicular to the optical axis direction,
The cover is formed so as to cover the cam ring, the compression coil spring, and the motor from the front side in the optical axis direction and to surround and hold the motor from the outside in cooperation with the base.
A lens driving device. The drive mechanism further includes a torsion coil spring that urges the cam ring to rotate in one direction.
The lens driving device according to claim 1. The torsion coil spring is disposed in an annular groove formed on the front surface of the base or formed to open toward the inner peripheral side of the cam ring.
The lens driving device according to claim 2. The motor includes a case that supports a rotating shaft to which a drive gear is fixed, a flange portion that is integrally formed with one end portion of the case and that can be fastened to the base, and that is integrally formed with the other end portion of the case. A fitting portion that is formed and can be fitted to the base,
The lens driving device according to claim 1, wherein the lens driving device is a lens driving device. The cover is formed to press and hold the compression coil spring.
The lens driving device according to claim 2, wherein the lens driving device is a lens driving device. The cylindrical portion has an outer peripheral surface that rotatably supports the cam ring,
The base has a restricting piece that restricts the cam ring from moving 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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