JP2009282243A - Lens driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens driving device capable of increasing a lens surface as much as possible by eliminating a frame portion, which is a part of a lens holder, from the periphery of the lens. <P>SOLUTION: The lens 9 provided on the lens driving device includes: a tongue-like projecting section 23 which projects from the external peripheral face 9a of the lens 9 in a direction perpendicular to an optical axis; and a first striking portion 24 located on the peripheral face 9a of the lens 9 on the basal end side of the projecting portion 23 and having an arcuate face around an optical axis. A lens holder 8 to which the lens 9 is fixed has: a projecting accommodating recess 26 receding from the free end 8e of the lens holder 8 and accommodating the projecting portion 23; and a first contact portion 27 which is located on the free end 8e side and with which a first striking portion 24 is disposed in contact. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lens driving device that is mounted on an optical unit (for example, a camera unit of a portable terminal or an optical pickup mechanism of an optical disk device) and used for lens focusing and lens spherical aberration correction.

  The optical pickup device described in Japanese Patent Laid-Open No. 2006-114117 includes a lens driving device that is used to correct spherical aberration of the lens. The lens driving device includes a worm gear that is rotated by a motor, and a movable lens holder. The lens holder is advanced and retracted in the optical axis direction by meshing with the provided rack portion. The lens holder is provided with a circular opening, and the lens is fixed in the opening.

JP 2006-114117 A

  However, since there is a frame portion that forms a part of the lens holder around the opening provided in the lens holder, the lens must be made smaller by the amount of this frame portion. The surface is required to be as large as possible due to its characteristics. In the past, it was difficult to resolve this conflicting situation.

  An object of the present invention is to provide a lens driving device in which a lens surface can be made as large as possible by eliminating a frame portion forming a part of a lens holder from the periphery of the lens.

The present invention provides a lens driving device mounted on an optical unit.
A lead screw rotated by a rotating shaft of the motor;
A lens holder that is fixed to the free end and reciprocates along the rotation axis of the lead screw by rotation of the lead screw;
A guide shaft that extends parallel to the rotation axis and penetrates and guides the lens holder;
The lens has a protrusion that protrudes from the outer peripheral surface of the lens in a direction orthogonal to the optical axis of the lens, and a first abutting portion that is located on the outer peripheral surface of the lens on the proximal end side of the protrusion. And
The lens holder includes a protrusion receiving recess that is recessed from the free end of the lens holder and receives the protrusion, and a first contact portion that is located on the free end side and that contacts the first abutting portion. It is characterized by that.

  Since the lens applied to this lens driving device is fixed to the lens holder in a cantilevered state, a frame part that forms a part of the lens holder is not required around the lens, and thereby the lens surface of the lens is made. It can be as large as possible. Further, in the present invention, the lens and the lens holder are devised when the lens is fixed to the lens holder in a cantilevered state. First, the lens has a protruding portion that protrudes from the outer peripheral surface of the lens in a direction orthogonal to the optical axis of the lens, and a first abutting portion that is located on the outer peripheral surface of the lens on the proximal end side of the protruding portion. . On the other hand, the lens holder is located on the free end side, and the first abutting portion where the first abutting portion comes into contact with the projection receiving concave portion that is recessed from the free end of the lens holder to receive the protruding portion. And a contact portion. Thus, the lens can be easily and reliably assembled to the lens holder with a simple structure.

Further, it is preferable that the first abutting portion has an arc centered on the optical axis.
When the lens is assembled to the lens holder, the first abutting portion of the lens comes into contact with the first abutting portion of the lens holder when the projection portion of the lens is inserted into the projection receiving recess of the lens holder. At this time, the first abutting portion is formed as an arc centered on the optical axis. Therefore, even if there is a clearance between the wall surface forming the projection receiving recess and the projection, the projection only moves around the optical axis in the projection receiving recess, so that the position of the optical axis of the lens may shift. In addition, the lens can be easily and accurately assembled to the lens holder.

In addition, a second abutting portion that extends on a plane orthogonal to the optical axis is formed on the projection portion of the lens, and the first wall surface that forms the projection accommodating recess is formed with respect to the axis of the guide shaft. It is preferable that the second contact portion extends on a plane orthogonal to each other and contacts the second butting portion.
In this case, the lens is positioned in the optical axis direction with respect to the lens holder by pressing the second butting portion of the lens against the second abutting portion (first wall surface) of the projection receiving recess. The lens can be more easily and accurately assembled to the lens holder while preventing the lens from being inclined and assembled.

Moreover, it is preferable that the second wall surface forming the protrusion accommodating recess is a protrusion restricting portion that restricts rotation about the optical axis of the protrusion.
The protrusion is restricted so as to move around the optical axis in the protrusion receiving recess, but the protrusion restricting part (second wall surface) that forms the protrusion receiving recess reliably controls the rotation of the protrusion. Therefore, the workability of assembling the lens with respect to the lens holder can be improved.

The lens is an I-cut lens having first and second cut surfaces parallel to each other on the outer peripheral surface, and the first and second cut surfaces preferably extend in parallel with the protruding direction of the protrusion. It is.
By using such an I-cut lens, it is possible to reduce the thickness of the lens driving device while increasing the lens surface.

  According to the present invention, the lens surface can be made as large as possible by eliminating the frame portion forming a part of the lens holder from the periphery of the lens.

  Hereinafter, a preferred embodiment of a lens driving device according to the present invention will be described in detail with reference to the drawings.

  In the optical pickup mechanism (optical unit) inside the optical disc apparatus, it is necessary to accurately focus the light beam on the information layer of the optical disc. For this reason, in a high-precision optical pickup mechanism, it is necessary to finely move the lens in the optical axis direction so that spherical aberration caused by the error in the thickness of the cover layer of the optical disk can be corrected.

  As shown in FIGS. 1 to 4, a lens driving device 1 mounted on an optical pickup mechanism (optical unit) is used for correcting spherical aberration of a lens, and includes two parallel frames 2a and 2b and a bottom plate 2c. In order to form a unit, the base member 2 is assembled with various parts to be described later.

  The stepping motor 3 is fixed to the frame 2a via a bracket 3a, and a lead screw 4 is fixed to the rotating shaft 3b of the motor 3 by press fitting. The lead screw 4 is inserted from an opening 2 d formed in the frame 2 a of the base member 2. And the front-end | tip of the rotating shaft 3b which protrudes from the lead screw 4 is rotatably supported by the bearing 6 fixed to the flame | frame 2b of the base member 2. As shown in FIG.

  The lead screw 4 penetrates the arm-shaped lens holder 8 and is screwed to the female screw portion 7. The lens holder 8 is always pressed against the female screw portion 7 by a spring force. The lens holder 8 has a portion 8A that protrudes outward from the base member 2, and this protruding portion 8A extends in the same direction as the extending direction of the frames 2a and 2b (see FIG. 3). . The pickup lens 9 is fixed to the free end 8 e side of the lens holder 8 by an adhesive, and the lens 9 is disposed outside the base member 2.

  A guide shaft 10 extending in parallel to the rotation axis L of the lead screw 4 is fixed to the base member 2 so as to bridge the frame 2a and the frame 2b. The guide shaft 10 is inserted into a guide hole 8 b formed in the lens holder 8. Therefore, by rotating the lead screw 4 forward and backward, the lens holder 8 reciprocates accurately along the axis P of the guide shaft 10, and accordingly, the axis P of the guide shaft 10 and the optical axis R of the lens 9. The lens 9 also moves in a straight line accurately so as to be parallel to each other.

  A compression coil spring 11 for urging the lens holder 8 in the extending direction of the rotation axis L is disposed in the base member 2, and the compression coil spring 11 is wound around the guide shaft 10. One end of the compression coil spring 11 is fixed to the frame 2 a, and the other end of the compression coil spring 11 is fixed to an end portion of an L-shaped leg portion 8 d extending from the lens holder 8. The guide shaft 10 extends through the leg portion 8d.

  The urging force of the compression coil spring 11 allows the lens holder 8 to be always pressed against the female screw portion 7, and the urging force also reaches the female screw portion 7, so the female screw portion 7 is attached to the lead screw 4. The lens holder 8 can be reliably screwed, and the feeding accuracy of the lens holder 8 is improved.

  Further, the base member 2 has a detent shaft having an axis S extending parallel to the rotation axis L of the lead screw 4 and the axis P of the guide shaft 10 so as to bridge the frame 2a and the frame 2b. 12 is fixed. The detent shaft 12 is inserted into a U-shaped notch 8 c formed at the end of the lens holder 8 so that the lens holder 8 rotates around the rotation axis L of the lead screw 4. It is regulated.

  As shown in FIGS. 1, 5 and 6, the lens 9 is an I-cut lens having first and second cut surfaces 21 and 22 parallel to each other on the outer peripheral surface 9a. Since the lens 9 is fixed to the lens holder 8 in a cantilevered state by an adhesive, a frame portion that forms a part of the lens holder 8 is not required around the lens, and thereby the lens surface of the lens 9 9b can be made as large as possible.

  The lens 9 used for correcting the spherical aberration has a width of 4 mm between the cut surfaces 21 and 22 and a diameter of 5 mm of the arc portion located on both sides of the cut surfaces 21 and 22 and is very small. Therefore, a device for increasing the lens surface 9b while reducing the outer shape is required in millimeters.

  The lens 9 is located on the outer peripheral surface 9 a of the lens 9 on the base end side of the protruding portion 23 and a tongue-like protruding portion 23 that protrudes from the outer peripheral surface 9 a of the lens 9 in a direction orthogonal to the optical axis R. And a first abutting portion 24 having an arc surface centered on the optical axis R. Further, the protrusion 23 and the first abutting portion 24 located on the proximal end side of the protrusion 23 are positioned between the first cut surface 21 and the second cut surface 22 and have an optical axis. It is juxtaposed in the R direction. And the front-end | tip of the projection part 23 is formed in semicircle shape.

  The lens holder 8 to which the lens 9 is fixed is located on the free end 8e side with a projection receiving recess 26 that is recessed from the free end 8e of the lens holder 8 and stores the projection 23, and the first abutting portion. And a first abutting portion 27 with which 24 abuts. The first abutting portion 27 is arranged in parallel with the projection receiving recess 26 in the direction of the optical axis R, and forms the same arc surface as the first abutting portion 24. Thereby, the lens 9 can be easily and reliably assembled to the lens holder 8 with a simple structure.

  When the lens 9 is assembled to the lens holder 8 with a jig, when the protrusion 23 of the lens 9 is inserted into the protrusion receiving recess 26 of the lens holder 8, the first abutting portion 24 of the lens 9 is attached to the lens holder 8. It abuts on the first abutment portion 27. At this time, the first abutting portion 24 is formed as an arc surface with the optical axis R as the center. Therefore, even if there is a clearance K (see FIG. 7) between the wall surface 26b forming the projection receiving recess 26 and the projection 23, the projection 23 only moves around the optical axis R in the projection receiving recess 26. Therefore, the position of the optical axis R of the lens 9 does not shift, and the lens 9 can be easily and accurately assembled to the lens holder 8.

  Furthermore, a second abutting portion 28 extending on a plane orthogonal to the optical axis R is formed on the projection portion 23 of the lens 9. On the other hand, the first wall surface 26a that forms the protrusion accommodating recess 26 extends on a plane orthogonal to the axis P of the guide shaft 10, and the second abutting portion 28 comes into contact therewith. It is a contact part.

  When the protrusion 23 of the lens 9 is inserted into the protrusion receiving recess 26 of the lens holder 8, the second abutting portion 28 of the lens 9 is moved to the second contact portion (first wall surface of the protrusion receiving recess 26. The lens 9 is positioned in the direction of the optical axis R with respect to the lens holder 8 by being pressed against the lens holder 8, and the lens 9 is prevented from being tilted and fixed to the lens holder 8, while the lens 9 is held in the lens holder 8. 8 can be more easily and accurately assembled.

  Further, as shown in FIGS. 1, 3, and 7, the second wall surfaces 26 b that form the protrusion receiving recesses 26 are formed in parallel to each other and are rotated around the optical axis R of the protrusion 23. It is a protrusion control part which regulates. Even if a clearance K for facilitating the assembly work of the lens 9 to the lens holder 8 exists between the second wall surface 26b and the protrusion 23, the protrusion restricting portions (second wall surfaces) 26b parallel to each other. As a result, the rotation of the projection 23 around the optical axis R can be reliably restricted, so that the workability of assembling the lens 9 with respect to the lens holder 8 can be improved.

  The lens 9 described above is an I-cut lens having first and second cut surfaces 21 and 22 that are parallel to each other on the outer peripheral surface 9 a, and the first and second cut surfaces 21 and 22 are formed on the protrusion 23. It extends parallel to the protruding direction. By using such an I-cut lens, the lens 9 can be accommodated within the thickness of the lens driving device 1 while increasing the lens surface 9b (see FIG. 3).

  Further, although the lens 9 can be fixed to the lens holder 8 by press-fitting, there is a possibility that the press-fitting location may be loosened due to temperature fluctuations, and heat caulking can be used. There is a risk of giving. Therefore, the lens 9 is fixed to the lens holder 8 with an adhesive applied to the wall surface forming the projection accommodating recess 26 and the first contact portion 27.

  Further, the lens holder 8 is provided with a semicircular adhesive reservoir recess 29 that communicates with the projection accommodating recess 26, and excess adhesive can be poured into the adhesive reservoir recess 29.

  It goes without saying that the present invention is not limited to the embodiment described above. For example, the lens driving device 1 may be mounted on an optical unit (for example, a camera unit of a mobile terminal) and used for lens focusing and lens spherical aberration correction. The lens 9 may be a normal circular lens. Further, either one of the first butting portion 24 and the first contact portion 27 may have a linear arc shape. Further, the first abutting portion 24 and the first abutting portion 27 may be such that the contact point is located on both sides of the protruding portion 23, even though the surface contact is not a circular arc surface. Good.

It is a perspective view which shows one Embodiment of the lens drive device which concerns on this invention. It is the perspective view which looked at the lens drive device from another angle. It is a front view of a lens drive device. It is a rear view of a lens drive device. It is sectional drawing which shows the joining state of a lens and a lens holder. It is sectional drawing which shows the joining state of a lens and a lens holder. It is a principal part enlarged view which shows the joining state of a lens and a lens holder.

Explanation of symbols

  R: optical axis, L: lead screw rotation axis, P: guide shaft axis, 1 ... lens driving device, 2 ... base member, 3 ... stepping motor, 3b ... rotation shaft, 4 ... lead screw, 8 ... lens holder 8e ... free end of lens holder, 9 ... lens, 9a ... outer peripheral surface of lens, 9b ... lens surface, 10 ... guide shaft, 11 ... coil spring, 21 ... first cut surface, 22 ... second cut surface, 23 ... Projection part, 24 ... First abutting part, 26 ... Projection accommodating recess, 26a ... First wall surface (second contact part), 26b ... Second wall surface (projection regulating part), 27 ... First 1 contact portion, 28... Second abutting portion.

Claims (5)

In the lens driving device mounted on the optical unit,
A lead screw rotated by a rotating shaft of the motor;
A lens holder that is fixed to the free end and reciprocates along the rotation axis of the lead screw by rotation of the lead screw;
A guide shaft that extends parallel to the rotation axis and penetrates and guides the lens holder,
The lens is
A protrusion protruding from the outer peripheral surface of the lens in a direction perpendicular to the optical axis of the lens;
A first abutting portion located on the outer peripheral surface of the lens on the base end side of the protrusion,
The lens holder is
A projection receiving recess that is recessed from the free end of the lens holder and receives the projection, and
A lens driving device comprising: a first abutting portion which is located on the free end side and abutted against the first abutting portion.   The lens driving device according to claim 1, wherein the first abutting portion forms an arc centered on the optical axis. The projecting portion of the lens is formed with a second abutting portion extending on a plane orthogonal to the optical axis,
The 1st wall surface which forms the said protrusion accommodation recessed part is a 2nd contact part which extends on the plane orthogonal to the axis line of the said guide shaft, and the said 2nd abutting part contact | abuts. The lens driving device according to claim 1, wherein:   The 2nd wall surface which forms the said protrusion accommodation recessed part is a protrusion control part which controls the rotation centering | focusing on the said optical axis of the said protrusion part, The Claim 1 characterized by the above-mentioned. The lens driving device described.   The lens is an I-cut lens having first and second cut surfaces parallel to each other on the outer peripheral surface, and the first and second cut surfaces extend in parallel with a protruding direction of the protrusion. The lens driving device according to any one of claims 1 to 4, wherein the lens driving device is used.

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