JPH1145454A - Objective lens driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an objective lens driving device equipped with a damper having a high vibration absorbing effect without falling out a weight constituting the damper. SOLUTION: A plate-like elastic piece 14 and a plate-like weight piece 15, in a damper constituted in an objective lens driving device, are piled up in this order on the outer circumferential surface 42 of a lens holder 4 and also a flexible printed circuit board 6 is fixed to the surface side of the plate-like weight piece 15 and is fixed also to the outer circumferential surface 42 of the lens holder 4 on the both sides of this weight piece 15. consequently, since the restrictive degree of the plate-like weight piece 15 is small, the free degree in the displacement of the plate-like weight piece is large and an vibration absorbing effect is high. In addition, since the plate-like weight piece 15 is also supported by the flexible printed circuit board 6, this weight piece does not fall out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective lens driving device of an optical pickup used for recording and reproducing an optical recording disk such as a CD (compact disk) and a DVD (digital video disk). More specifically, the present invention relates to an anti-vibration structure of a lens holder holding an objective lens.

[0002]

2. Description of the Related Art An objective lens driving device of an optical pickup used for recording and reproducing an optical recording disk such as a CD or a DVD includes a lens holder holding an objective lens, and a lens holder.
There is a known lens holder having a lens holder that supports the lens holder so as to be movable in a focusing correction direction and a tracking correction direction of an objective lens, and a magnetic circuit that drives the lens holder.

In an objective lens driving device having this structure, a vibration absorber (damper) is attached to the outer peripheral surface of a lens holder to suppress resonance when the lens holder is driven. For example, Japanese Patent Laying-Open No. 3-154235 discloses a structure in which a cylindrical damper member having elasticity is fitted in a hole formed in a lens holder, and a balance weight body is mounted inside the damper member. Also,
Japanese Utility Model Application Laid-Open No. 63-40819 discloses an apparatus in which a rubber-based adhesive is applied to a hole formed in a lens holder, and a balancer is fixed with the rubber-based adhesive. These embedded dampers have the advantage that the weight bodies such as the balance weight body and the balancer do not fall off.

On the other hand, JP-A-3-113839 discloses a lens holder in which a weight is adhered to an outer peripheral surface of a lens holder and a vibration absorbing member such as rubber is superposed on the surface. Such a cantilevered damper has a small degree of restraint, and thus has an advantage that the degree of freedom of deformation is greater than that of an embedded damper.

[0005]

However, among the above damper mechanisms, the former embedded type has an advantage that the weight body does not fall off, but has a large degree of restraint, so that the vibration absorbing effect is small. There is a problem. On the other hand, in the latter cantilever type, since the degree of restraint of the damper is small, the damper may fall off due to local vibration. Also, JP-A-3-113
No. 839, the weight and the vibration absorbing member are stacked in this order on the outer peripheral surface of the lens holder.
There is also a problem that the mass component of the damper is small and the vibration absorbing effect is not sufficient.

[0006] In view of the above problems, an object of the present invention is to provide:
The weights that make up the damper do not fall off, and
An object of the present invention is to provide an objective lens driving device provided with a damper having a high vibration absorbing effect.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a lens holder holding an objective lens and a movable lens holder in a focusing correction direction and a tracking correction direction of the objective lens. A supporting holder supporting member, a focusing driving coil and a tracking driving coil attached to one of the lens holder and the holder supporting member, and a focusing driving magnet and a tracking driving magnet attached to the other; and In an objective lens driving device having a damper formed on an outer peripheral surface, the damper includes a plate-shaped elastic piece fixed to an outer peripheral surface of the lens holder, and a plate-shaped weight fixed to a surface of the plate-shaped elastic piece. A weight piece, and a film is fixed on the surface side of the plate-shaped weight piece. With that, the film is,
The lens holder is fixed to both sides of the plate-shaped weight piece on the outer peripheral surface of the lens holder.

In the damper constructed in the objective lens driving device according to the present invention, since the plate-like elastic piece and the plate-like weight piece are fixed to the outer peripheral surface of the lens holder in this order, the degree of constraint of the plate-like weight piece is Is small. Therefore, since the plate-shaped weight piece has a large degree of freedom of displacement, the vibration absorbing effect is high. Further, a film is fixed to the surface of the plate-shaped weight piece, and the film is also fixed to both sides of the plate-shaped weight piece on the outer peripheral surface of the lens holder. In a state supported by the holding structure. Therefore, the plate-shaped weight piece does not fall off even if it vibrates locally. Moreover, since a flexible film that does not hinder the vibration of the plate-shaped weight piece is used to prevent the plate-shaped weight piece from falling off, the degree of freedom of the plate-shaped weight piece is not reduced. A high vibration absorbing effect can be obtained.

In the present invention, the film is preferably a flexible printed circuit board for supplying a current to the drive coil. With this configuration, it is not necessary to attach another member to support the damper, so that the number of assembly steps and the number of parts do not increase. Therefore, the objective lens driving device can be manufactured at low cost.

In the present invention, the holder support member has a support shaft for the lens holder, and the lens holder has a shaft hole into which the support shaft is inserted, and the damper is provided in the lens holder. It is preferable that the portion holding the objective lens is formed at a diagonal position sandwiching the shaft hole. With this configuration, the weights of the objective lens side and the damper side can be balanced with respect to the shaft hole. That is, the damper can be used as a balancer for the objective lens. Therefore, it is possible to stably drive the lens holder.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

(Overall Configuration) FIG. 1 is a plan view showing an objective lens driving device to which the present invention is applied. FIG. 2 is a sectional view taken along line II-II in FIG.

As shown in FIGS. 1 and 2, an objective lens driving device 1 according to the present invention comprises a lens holder 4 holding an objective lens 11, and a focusing correction direction and a tracking correction direction of the objective lens 11. And a holder support member 5 (yoke / frame) movably supported by the holder.

The holder support member 5 has a circular bottom wall 51, and the support shaft 12 stands upright from the center. A cylindrical outer yoke 52 rises from the outer peripheral edge of the bottom wall 51 and surrounds the outer peripheral surface 42 of the lens holder 4.

The lens holder 4 has a substantially cylindrical body 41.
And a cylindrical bearing 43 concentrically arranged inside the body 41, and the body 41 and the bearing 43 are connected by a plurality of ribs 45. At the upper end of the body 41, an objective lens attaching portion 46 is formed, and the objective lens 11 is adhered to the objective lens attaching portion 46. The inside of the bearing 43 is the shaft hole 4
The support shaft 12 is inserted into the shaft hole 44. Thus, the support shaft 12 is inserted into the shaft hole 44.
When the lens holder 4 is inserted, the lens holder 4 is rotatable around the support shaft 12 and is also slidable in the axial direction.

The inner peripheral surface 53 of the outer yoke 52 has a support shaft 1
Two focusing drive magnets 23 and 24 polarized in the direction of the axis L, and two tracking drive magnets 25 polarized in the direction around the axis L;
26 are adhered. On the other hand, on the outer peripheral surface 42 of the lens holder 4, two focusing drive magnets 23,
Two focusing drive coils 19 and 20 are bonded to face each other, and two tracking drive coils 21 and 22 are bonded to face two tracking drive magnets 25 and 26, respectively. A flexible printed circuit board 6 (hereinafter, referred to as an FPC board 6) bridged between the holder support member 5 and the lens holder 4 is provided between the focusing drive coils 19 and 20 and the tracking drive coils 21 and 22.
Can supply current. In this way, a focusing magnetic circuit is formed between the focusing drive coils 19, 20 and the focusing drive magnets 23, 24, and moves the lens holder 4 in the direction of the axis L (the direction of arrow A in FIG. 2). Focusing correction of the objective lens 11 can be performed. The tracking drive coils 21 and 22 and the tracking drive magnet 2
A tracking magnetic circuit is formed between 5 and 26, and the lens holder 4 can be rotated around the axis L (the direction of arrow B in FIG. 1) to perform tracking correction of the objective lens 11.

(Vibration Isolation Structure of Lens Holder) A damper 13 is provided on the outer peripheral surface 42 of the lens holder 4 to prevent the lens holder 4 from vibrating when the lens holder 4 is driven.
Is configured. The damper 13 is mounted diagonally to the objective lens mounting portion 46 with the shaft hole 44 interposed therebetween, and is balanced with the objective lens 11 in weight.
That is, the damper 13 also functions as a balancer for the objective lens 11.

FIG. 3 is an exploded perspective view showing the lens holder 4 taken out.

As shown in FIG. 3, the objective lens mounting portion 4 is sandwiched between the shaft holes 44 in the outer peripheral surface 42 of the lens holder 4.
A concave portion 47 is formed at a position diagonal to 6, and the damper 13 is disposed therein.

The damper 13 includes a substantially rectangular thin plate-like elastic piece 14 made of an elastic material such as chloroprene rubber and a substantially rectangular thin plate-shaped weight piece 15 made of metal such as brass. The plate-like elastic piece 14 is fixed to the inside of the concave portion 47 of the outer peripheral surface 42 of the lens holder 4 by a method such as an adhesive, an adhesive, or baking.
A plate-shaped weight piece 15 is fixed to the surface of the sheet by an adhesive, a pressure-sensitive adhesive, or a method such as baking. Therefore, the vibration of the lens holder 4 is absorbed and suppressed by the plate-like elastic piece 14 and the damper 13 formed by the plate-like elastic piece 14. Therefore, focusing correction and tracking correction can be performed stably.

The outer peripheral surface 42 of the lens holder 4 has
An FPC board 6 (film) for supplying power to the drive coil is attached so as to straddle the damper 13. The FPC board 6 includes a substantially rectangular attachment portion 61 that is fixed to the outer peripheral surface 42 of the lens holder 4, and a routing portion 62 that extends from the attachment portion 61 to the holder support member 5. The central portion 63 of the attaching portion 61 is fixed to the surface of the plate-shaped weight piece 15 using an adhesive or an adhesive, and both side portions 64 and 65 of the attaching portion 61 are attached to the outer peripheral surface 42 of the lens holder 4. Of these, the plate-shaped weight piece 15 is fixed to both side regions using an adhesive or an adhesive.

As described above, in the damper 13 configured in the objective lens driving device 1 of the present embodiment, the plate-shaped elastic piece 14 and the plate-shaped weight piece 15 are fixed to the outer peripheral surface 42 of the lens holder 4 in this order. The degree of constraint of the plate-shaped weight piece 15 is small. That is, the plate-shaped weight piece 15 is
And can be freely displaced within a range where it can be deformed, and the degree of freedom of displacement is large. An FPC board 6 for supplying power to the drive coil is fixed to the surface of the plate-shaped weight piece 15, and the FPC board 6 is also provided on both sides of the plate-shaped weight piece 15 in the outer peripheral surface 42 of the lens holder 4. It is fixed. For this reason, the plate-shaped weight piece 15 is in a state of being supported by the double-sided structure. Therefore, the plate-shaped weight piece 15 does not fall off even if locally vibrated largely. In addition, since the FPC board 6 having flexibility that does not hinder the vibration of the plate-shaped weight piece 15 is used to prevent the plate-shaped weight piece 15 from falling off, the degree of freedom of the plate-shaped weight piece 15 is reduced. A high vibration absorbing effect can be obtained without lowering. As described above, the objective lens driving device 1 of the present embodiment has both the advantages of the embedded type and the cantilever type described in the related art, so that the vibration absorbing effect is high and the reliability is high.

In this embodiment, the objective lens driving device 1
Since the damper 13 is supported by partially improving the structure of the conventional FPC board 6 for supplying the drive coil to the lens holder 4, it is not necessary to attach another member to support the damper 13. Therefore, the number of assembly steps and the number of parts do not increase, and the objective lens driving device 1 can be manufactured at low cost.

(Other Embodiments) As a member for supporting the damper 13, a flexible film such as FP
The substrate need not be the C substrate 6. When a film other than the FPC board 6 is used to support the damper 13, the focusing drive coils 19, 20
And the tracking drive coils 21 and 22 are attached to the holder support member 5 side, and the focusing drive magnet 2
3, 24 and tracking drive magnets 25, 26
Can be attached to the lens holder 4 side.

Further, the material of the plate-like elastic piece 14 is not limited to chloroprene rubber, and a member having another elasticity may be used. Similarly, the material of the plate-shaped weight piece 15 is not limited to brass, and another metal or the like may be used.

Further, the mounting position of the damper 13 is not limited to a diagonal position with respect to the objective lens mounting portion 11 with the shaft hole 44 interposed therebetween, but may be provided at a plurality of positions. In this case, if the plurality of dampers 13 are arranged at diagonal positions, each damper 13 functions effectively. At this time, it is preferable that the dampers 13 are arranged so as to function as a balancer for the objective lens 11 as a result of adjusting their masses.

If it is not necessary to use the damper 13 as a balancer, it is a matter of course that the damper 13 should be arranged at the most effective position from the viewpoint of vibration absorption.

[0028]

As described above, in the damper of the objective lens driving device according to the present invention, the plate-shaped elastic piece and the plate-shaped weight piece are stacked on the outer peripheral surface of the lens holder in this order, and On the surface side of the weight piece, a film fixed on both sides thereof to the outer peripheral surface of the lens holder is also fixed. Therefore, in the damper according to the present invention, since the degree of constraint of the plate-shaped weight piece is small, the plate-shaped weight piece has a large degree of freedom of displacement and a high vibration absorbing effect. Further, a film is fixed on the surface of the plate-shaped weight piece, and the film is also fixed on both sides of the plate-shaped weight piece on the outer peripheral surface of the lens holder, so that the plate-shaped weight piece falls off. Never do. Moreover, since a flexible film that does not hinder the vibration of the plate-shaped weight piece is used to prevent the plate-shaped weight piece from falling off, the degree of freedom of the plate-shaped weight piece is not reduced. A high vibration absorbing effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view of an objective lens driving device according to the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is an exploded perspective view showing a lens holder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Objective lens drive device 4 Lens holder 5 Holder support member (film) 6 FPC board 11 Objective lens 12 Support shaft 13 Damper 14 Plate elastic piece 15 Plate weight piece 19, 20 Focusing drive coil 21, 22 Tracking drive coil 23 , 24 Focusing drive magnet 25, 26 Tracking drive magnet 42 Outer peripheral surface of lens holder 44 Shaft hole L axis

Claims (3)

[Claims] A lens holder holding an objective lens;
A holder support member that movably supports the lens holder in a focusing correction direction and a tracking correction direction of the objective lens; a focusing drive coil and a tracking drive coil attached to one of the lens holder and the holder support member; An objective lens driving device having a focusing driving magnet and a tracking driving magnet attached to the other, and a damper formed on the outer peripheral surface of the lens holder, wherein the damper is fixed to the outer peripheral surface of the lens holder. A plate-shaped elastic piece, and a plate-shaped weight piece fixed to the surface of the plate-shaped elastic piece. A film is fixed to a surface side of the plate-shaped weight piece, and the film is the lens The outer peripheral surface of the holder is also fixed to both side regions of the plate-shaped weight piece. An objective lens driving device according to claim Rukoto. 2. The objective lens driving device according to claim 1, wherein the film is a flexible printed circuit board for supplying a current to the driving coil. 3. The holder support member according to claim 1, wherein the holder support member includes a support shaft of the lens holder, and the lens holder has a shaft hole into which the support shaft is inserted.
The objective lens driving device, wherein the damper is configured at a diagonal position with respect to a portion of the lens holder holding the objective lens, with the shaft hole interposed therebetween.