JPH11154341A - Objective lens drive device for optical pickup - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an objective lens drive device for an optical pickup providing a rotation allowable range of a lens holder without an inner yoke and also setting the rotation allowable range of the lens holder wider. SOLUTION: In the objective lens drive device 1, a stopper mechanism 7 providing the rotation allowable range of the lens holder 2 is constituted of lens hold parts 25, 26 formed on the lens holder 2 and abutment parts 71, 72 formed on a cover 6 covering the upper surface 231 of the lens holder 2. The abutment parts 71, 72 are provided with terminal edges 612, 613 of an opening 611 formed on the cover 6 and end surfaces 631, 632 of a get-into preventive projection 63 prolonging from the terminal edges 612, 613 to an axial line directional lower side. When the lens holder 2 exceeds to rotate, the lens hold parts 25, 26 are abutted on the abutment parts 71, 72, and the over rotation of the lens holder 2 is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an objective lens driving device of an optical pickup for recording and reproducing data on and from an optical disk such as a CD (compact disk) and a DVD (digital video disk). More specifically, in a shaft sliding type objective lens driving device in which a lens holder holding an objective lens moves along a sliding axis, in order to prevent the lens holder from rotating more than necessary around the sliding axis. It is related to the mechanism of.

[0002]

2. Description of the Related Art As an objective lens driving device of an optical pickup for recording and reproducing data on and from an optical disk such as a CD and a DVD, a lens holder holding an objective lens, a sliding shaft supporting the lens holder, An axis having a focusing magnetic circuit that moves the lens holder along the sliding axis to perform focusing correction of the objective lens, and a tracking magnetic circuit that rotates the lens holder around the sliding axis to perform tracking correction of the objective lens. A sliding type is known.

In this type of objective lens driving device, in order to increase the magnetic efficiency of the magnetic circuit, an outer yoke having a shape surrounding the outer peripheral surface of the lens holder is formed, and an inner yoke is formed in a through hole formed in the lens holder. Is arranged.
A gap is formed between the through hole and the inner yoke so that the lens holder can rotate by an angle necessary for performing tracking correction. When the lens holder rotates more than necessary, the inner yoke hits the inner peripheral surface of the through hole, and thus also plays a role in defining the allowable rotation range of the lens holder. That is, if the lens holder is rotated more than necessary, the flexible printed circuit board for supplying power to the magnetic circuit that is bridged between the lens holder and the outer yoke is greatly twisted, damaging the flexible printed circuit board,
This is because there is a possibility that a problem that the objective lens enters the lower side of the cover of the outer yoke and the lens holder cannot be driven may occur.

[0004]

In such an objective lens driving device, there is a case where the allowable rotation range of the lens holder must be expanded. For example, with the advent of the DVD standard, a plurality of objective lenses such as a CD and a DVD are mounted on a lens holder, and the lens holder is largely rotated so that any one of these objective lenses can be used. An objective lens driving device for rotationally moving the lens holder has been developed, and in this type of objective lens driving device, the rotation allowable range of the lens holder must be expanded. However, in the above-described conventional objective lens driving device, the inner yoke is troublesome to rotate the lens holder largely in order to switch the lens position. However,
If the inner yoke is removed, there is no one that defines the allowable rotation range of the lens holder.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an objective lens driving device for an optical pickup in which the allowable rotation range of the lens holder can be defined without providing the inner yoke, and the allowable rotation range of the lens holder can be set wide. Is to do.

[0006]

In order to solve the above-mentioned problems, the present invention provides a lens holder for holding an objective lens in a lens holding portion, and a fixed member having a sliding shaft for supporting the lens holder. An objective lens driving device for an optical pickup supported by the lens holder, the lens holder being movable with respect to the fixed side member in an axial direction of the sliding shaft and rotatably around the axis. A stopper mechanism is provided between the fixed-side member and an outer end surface (upper end surface or side end surface) of the lens holder, the stopper mechanism defining an allowable rotation range of the lens holder around the axis with respect to the fixed-side member. It is characterized by.

According to the present invention, a stopper mechanism for defining the allowable rotation range of the lens holder around the axis with respect to the fixed member by using the space between the fixed member and the outer end surface of the lens holder is provided. It is easy to extend the allowable rotation range of the lens holder. That is,
When the stopper mechanism is configured by utilizing the inside of the lens holder, all of the angle corresponding to the rotation permissible range inside the lens holder in the through hole through which the inner yoke can move is equivalent to the wide rotation permissible range. Therefore, a great restriction is imposed on the internal configuration of the lens holder. However, in the present invention, since the stopper mechanism is configured by using the space between the fixed side member and the outer end surface of the lens holder, even when the rotation allowable range is set to be wide, a great restriction is imposed on the configuration of the lens holder. Nothing.

In the present invention, the stopper mechanism includes a holder-side projecting portion comprising the objective lens or the lens holding portion projecting upward from an upper end surface of an outer end surface of the lens holder on the lens holder side; On the side of the fixed side member, the holder-side protruding portion that rotates around the axis abuts, and can be configured by a contact portion that defines a rotation allowable limit position of the lens holder in this direction. In the lens holder, the objective lens or the lens holder often protrudes from the upper end surface of the lens holder. If these are used as they are as the protrusions on the holder side of the stopper mechanism, a new protrusion is formed for the lens holder. No need to do.

In this case, the contact portion is formed on a cover which covers the lens holder on a side plate surrounding the side end surface of the lens holder on the side of the fixed member. can do. For example, when the cover is formed with an opening cut out along the locus of the holder-side protruding portion accompanying the rotation of the lens holder within the rotation allowable range, the inner peripheral edge of the opening forms the opening. The contact can be configured. in this way,
In the type in which the cover is provided on the side of the fixed side member, an area corresponding to the objective lens is originally an opening. Therefore, if the formation range of the opening formed in the cover is adjusted to the rotation allowable range, the inner peripheral edge of the opening can be used as a contact portion of the stopper mechanism.

In this case, the holder-side protruding portion includes a protruding portion that protrudes radially outward from a side end surface of the lens holder, and the abutting portion is radially outward from an outer end surface of the lens holder. At a position, the projection extends downward from the inner peripheral edge of the opening and has a protrusion for preventing the protrusion from coming into contact even when the lens holder rotates around the axis at the lower limit position in the axial direction of the sliding shaft. Is preferred. The lens holder may move in the axial direction of the sliding shaft, and rotate around the axis at its lower limit position, for example. Even in such a case, if the projection for preventing sneaking is formed on the contact portion, the lens holder does not sneak under the cover.

In the present invention, it is preferable that the fixed side member has an engagement mechanism between the cover and the side plate for preventing the cover from rotating relative to the side plate. If the contact portion of the stopper mechanism is formed on the cover, a corresponding force is applied to the cover when the rotation of the lens holder is prevented. Even so, if an engagement mechanism is configured between the cover and the side plate, the cover will not run idle even when the cover prevents the rotation of the lens holder.

In the present invention, in forming the stopper mechanism, an opening formed in an outer end surface of the lens holder over an angle range corresponding to the rotation allowable range, and an opening formed in the opening from the fixed member side. An abutting portion may be used that defines an allowable rotation position of the lens holder in this direction by contacting an inner peripheral edge of the opening that protrudes and rotates around the axis.

Since the objective lens driving mechanism according to the present invention is effective when the allowable rotation range is wide, the lens holder holds the two objective lenses in the respective lens holders, and the objective lens driving mechanism of the lens holder. This is suitable for a type in which the relative positions of the two objective lenses with respect to the fixed member are switched by rotation about an axis. In this case, the stopper mechanism allows the lens holder to rotate around the axis in a lens switching direction for switching the positions of the two objective lenses, while allowing the lens holder to rotate in a direction opposite to the lens switching direction. It is configured to stop rotation about the axis within a predetermined angle range.

In the present invention, the lens holder is
Holding the two objective lenses in respective lens holders,
Further, in an objective lens driving mechanism configured so that the relative position of the two objective lenses with respect to the fixed side member is switched by rotation of the lens holder around the axis, the stopper mechanism is configured to switch between the two objective lenses. The rotation about the axis of the lens holder in the direction opposite to the lens switching direction for switching the position is stopped within a predetermined angle range, and the rotation about the axis of the lens holder in the lens switching direction is the axis of the lens holder. In some cases, rotation around the axis at the lower limit position in the direction is allowed, and rotation about the axis of the lens holder at a position above the lower limit position is stopped within a predetermined angle range. With this configuration, when tracking correction is performed for one objective lens, the lens holder does not rotate around the axis so much that the other objective lens is selected by mistake. In addition, since the stopper mechanism allows the rotation of the lens holder about the axis in the lens switching direction about the axis at the lower limit position in the axis direction of the lens holder, there is no problem in switching the objective lens.

[0015]

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

(Overall Configuration of Objective Lens Driving Apparatus) FIG.
1A and 1B are a plan view showing an objective lens driving device of an optical pickup to which the present invention is applied, and FIG.
FIG. 2 is a cross-sectional view of the yoke of the objective lens driving device shown in FIG.

As shown in FIGS. 1A and 1B, the objective lens driving device 1 supports a lens holder 2 holding a CD objective lens 8 and a DVD objective lens 9, and supports the lens holder 2. And a fixed member 5 having a yoke 4 to which the sliding shaft 3 is fixed.

The yoke 4 is formed in a cup shape having a bottom wall 41 and a side plate 42 that rises in a cylindrical shape from the bottom wall 41 and surrounds the outer peripheral surface (side end surface) of the lens holder 2. The sliding shaft 3 is press-fitted and fixed at the center of the bottom wall 41. A plastic cover 6 is attached to the upper end 421 of the side plate 42 so as to cover the upper surface 231 of the lens holder 4.

On the inner peripheral surface of the side plate 42, the axis L of the sliding shaft 3 is provided.
A pair of tracking drive magnets 11 and 12 are fixed at an angular interval of 180 ° with respect to the center. A pair of focusing drive magnets 13 and 14 are fixed at positions shifted by 90 ° from the tracking drive magnets 11 and 12 at an angular interval of 180 °.

The lens holder 2 includes a cylindrical body 21 having an upper end plate 23 and a cylindrical bearing 22 extending coaxially with the body 21 at the center of the body 21. The upper end plate 23 has C at an angular interval of 90 ° about the axis L.
A CD lens holding unit 25 holding the D objective lens 8 and a DVD lens holding unit 26 holding the DVD objective lens 9 are formed. The inner peripheral surface of the bearing portion 22 is a shaft hole 24, into which the sliding shaft 3 is inserted.

An outer peripheral surface 211 of the body 21 has four drive coils 15 to 1 at an angular interval of 90 ° about the axis L.
8 is attached. A flexible printed circuit board 19 is stretched between the lens holder 2 and the yoke 4 in a loose state, and current is supplied to the drive coils 15 to 18 via the flexible printed circuit board 19.

The magnetic cores 151, 161, 171, and 181 are provided on the outer peripheral surface 211 of the lens holder 2 where the drive coils 15 to 18 are mounted.
Is attached. Therefore, the drive coils 15 to 18
When no current is supplied to the magnetic core 151,
161, 171 and 181 are tracking drive magnets 11 and 12 or focusing drive magnets 1;
Magnetic attraction is performed at the magnetic center positions 3 and 14. For this reason, the lens holder 2 is held at a rotation angle at which the drive coils 15 to 18 face the tracking drive magnets 11 and 12 or the focusing drive magnets 13 and 14, and at a neutral position substantially at the center in the direction of the axis L. You.

Here, the objective lens driving device 1 switches the objective lens 8 for CD and the objective lens 9 for DVD by rotating the lens holder 2 by about 90 ° around the axis. When the lens holder 2 is at the angular position shown in FIG. 1A, the DVD objective lens 9 can be used. In this state, the drive coils 15 and 16 face the tracking drive magnets 11 and 12, and a tracking magnetic circuit that rotates the lens holder 2 around the axis L is formed between them. The focusing drive magnets 13 and 14 have drive coils 17 and 1 respectively.
8, a focusing magnetic circuit for moving the lens holder 2 in the direction of the axis L is formed between them.
With these magnetic circuits, tracking correction and focusing correction of the DVD objective lens 9 are performed.

To switch from this state to a state in which the CD objective lens 8 can be used, a kick pulse is input to the tracking magnetic circuit, and the lens holder 2 is rotated by 90 ° in the direction of arrow B (lens switching direction). In this manner, the CD objective lens 8 is arranged at the position where the DVD objective lens 9 is arranged, and the driving coils 15 and 16 which have been opposed to the tracking drive magnets 11 and 12 are moved to the focusing drive magnet. 1
A focusing magnetic circuit is formed facing 4 and 13,
The drive coils 17 and 18 facing the focusing drive magnets 13 and 14 face the tracking drive magnets 11 and 12 to form a tracking magnetic circuit. By these magnetic circuits, tracking correction and focusing correction of the CD objective lens 8 are performed.

To switch from this state to a state where the DVD lens 9 can be used again, a kick pulse is input to the tracking magnetic circuit, and the lens holder 2 is rotated by 90 ° in the direction of arrow A (lens switching direction). I just need.

(Stopper mechanism) In order to prevent the lens holder 2 from being excessively rotated by the inertial force when performing tracking correction of the objective lenses 8 and 9 and switching of the objective lenses 8 and 9 in this manner, In the present embodiment, a stopper mechanism 7 is provided between the lens holder 2 and the fixed-side member 5 to define an allowable rotation range of the lens holder 2 with respect to the fixed-side member 5. The stopper mechanism 7 is configured using a CD lens holding portion 25 (holder-side protrusion) and a DVD lens holding portion 26 (holder-side protrusion) formed on the lens holder 2, and the cover 6. I have.

FIG. 2 is an exploded perspective view of the objective lens driving device 1 with the cover 6 removed from the yoke 4. FIG.
As shown in FIG. 2 and FIG. 2, the CD lens holder 25 and the DVD lens holder 2 formed on the lens holder 2 are provided.
Numeral 6 is formed in an annular shape along the outer peripheral edge of each of the objective lenses 8 and 9, and protrudes in the axial direction from the upper surface 231 of the lens holder 2. The amount of protrusion is determined by the lens holder 2
Each lens holding part 25, 2 is held in a state where
6 is set so as to protrude above the cover 6, and C
The D lens holder 25 is the DVD lens holder 26
It is set larger than. Further, a part of the CD lens holding portion 25 and a part of the DVD lens holding portion 26 are overhang portions 251 and 261 which protrude radially outward from the outer peripheral surface 211 of the lens holder 2.

On the other hand, the cover 6 includes a top plate 61 which covers the upper surface 231 of the lens holder 2, and a cylindrical portion 62 which is bent downward from the outer peripheral edge of the top plate 61 and is in close contact with the outer peripheral surface of the upper end portion of the side plate 42 of the yoke 4. It has. A substantially C-shaped opening 611 is formed in the top plate 61. This opening 611 is
The CD lens holder 25 and the DVD lens holder 26 are notched along the trajectory that moves as the lens holder 2 rotates. Of the inner peripheral edge of the opening 611, both end edges 61 in the circumferential direction around the axis L (directions indicated by arrows A and B)
2 and 613 are outer peripheral surfaces 25 of the lens holding portions 25 and 26.
2, 262 are formed in an arc shape.

At a position radially outside the outer peripheral surface 211 of the lens holder 2 on the lower surface of the top plate 61 (the surface facing the lens holder 2), a projection 63 for preventing sneaking is provided extending downward. 2 is formed in an arc shape along the outer peripheral surface 211. The circumferential end surfaces 631 and 632 of the anti-subtraction protrusion 63 are curved along both end edges 612 and 613 of the opening 611, respectively.
It is at the position that matches 13.

In this embodiment, the opening 6 formed in the top plate 61
11 and an end surface 631 of the anti-subtraction projection 63 are a contact portion 71 that can contact the CD lens holding portion 25 in the circumferential direction, and the lens in this direction (the direction of arrow A). The rotation allowable limit position of the holder 2 is defined. The edge 613 of the opening 611 and the end surface 632 of the anti-slipping projection 63 constitute a contact portion 72 that can contact the DVD lens holding portion 26 in the circumferential direction. Lens holder 2 in)
Stipulates the permissible rotation limit position. Therefore, the permissible rotation range of the lens holder 2 with respect to the fixed side member 5 is set such that the outer peripheral surface 262 of the DVD lens holder 26 contacts the abutment portion 72 from the position where the outer peripheral surface 252 of the CD lens holder 25 contacts the contact portion 71. Is set up to the position corresponding to.

The objective lens driving device 1 thus formed
3A and 3B will be described with reference to FIGS. 3A and 3B. First, FIG.
As shown in FIG. 7A, when the DVD objective lens 9 is used, if the lens holder 2 is at the neutral position, the outer peripheral surface 252 of the CD lens holding portion 25 has a gap at the edge 612 of the opening 611. Facing each other. When performing tracking correction of the DVD objective lens 9, the lens holder 2 is rotated in the direction of arrow A by the gap between the edge 612 of the opening 611 and the outer peripheral surface 252 of the CD lens holding portion 25. Can be done.

Here, when the lens holder 2 is rotated with a large acceleration in the direction of arrow A (the direction opposite to the lens switching direction from this state) to perform tracking correction, the inertia force is applied to the lens holder 2. Is added, and the lens holder 2 may try to rotate more than necessary in the direction of arrow A. When switching from the state using the CD objective lens 8 to the state using the DVD objective lens 9, the direction of the arrow A (the lens switching direction from this state and the switching direction from this state) is maintained even after the lens position is switched. In the opposite direction), an inertial force is applied to the lens holder 2 and the lens
May try to rotate more than necessary. In such a case, the outer peripheral surface 252 of the CD lens holding portion 25 hits the edge 612 of the opening 611 and the end surface 631 of the anti-slipping projection 63 in the circumferential direction, and the rotation is stopped.

Here, if the lens holder 2 is located above the neutral position in the axial direction due to the focusing correction, the CD lens holding section 25 is moved to the top plate 61.
Is slightly protruded above the upper surface of the CD lens holding portion 25 on the entire edge 612 of the opening 611 and the end surface 631 of the anti-subtraction projection 63.
2 come into contact with each other, and the rotation of the lens holder 2 is stopped. On the other hand, when the lens holder 2 is located below the neutral position in the axial direction (lower limit position), the CD lens holder 2
5 is located at a height between the upper surface and the lower surface of the top plate 61, and the outer peripheral surface 252 of the CD lens
The edge 11 abuts 612 only shallowly. Nevertheless, the end surface 631 of the anti-submersion projection 63 has an edge 612.
The protrusion 251 of the CD lens holding portion 25 abuts in the circumferential direction on the end surface 631 of the projection 63 for preventing sneaking in, since the projection 63 extends further downward in the axial direction. Therefore, the rotation of the lens holder 2 can be reliably stopped. As described above, the contact portion 71 can reliably prevent the lens holder 2 from turning too much in the direction of arrow A, regardless of the position of the lens holder 2 in the axial direction.

On the other hand, as shown in FIG. 3B, in the state where the objective lens 8 for CD is used, if the lens holder 2 is at the neutral position, the lens holder for DVD is attached to the edge 613 of the opening 611. The outer peripheral surfaces 262 of the pair 26 face each other with a gap. When performing tracking correction of the CD objective lens 8, the lens holder 2 is rotated in the direction of arrow B by the gap between the edge 613 of the opening 611 and the outer peripheral surface 262 of the DVD lens holding portion 26. Can be done.

Here, when the lens holder 2 is rotated at a large acceleration in the direction of arrow B (the direction opposite to the lens switching direction from this state) in order to perform tracking correction, the inertia of the lens holder 2 is increased. When a force is applied, the lens holder 2 tries to rotate more than necessary in the direction of arrow B. Further, when switching from the state using the DVD objective lens 9 to the state using the CD objective lens 8, the inertia force is applied to the lens holder 2 even after the switching of the lens position, and the lens holder 2 is moved by the arrow. Attempts to rotate more than necessary in the direction B (the direction opposite to the lens switching direction from this state). Even in such a case, the edge 613 of the opening 611 and the end surface 632 of the anti-subtraction projection 63 are not
The outer peripheral surface 262 of the VD lens holding portion 26 hits in the circumferential direction, and its rotation is stopped.

Here, since the focusing correction is also performed, when the lens holder 2 is located above the neutral position in the axial direction, the upper end of the DVD lens holding portion 26 is located between the upper and lower surfaces of the top plate 61. At the height of C
The outer peripheral surface 252 of the D lens holding portion 25 shallowly hits the edge 613 of the opening 611 and the protrusion 63
, And the rotation of the lens holder 2 is stopped.

On the other hand, when the lens holder 2 is located below the neutral position in the axial direction (lower limit position), the DV
The upper end of the D lens holder 26 is located below the lower surface of the top plate 61, and the outer peripheral surface 262 of the DVD lens holder 26 does not come into contact with the edge 613 of the opening 611. . Nevertheless, in the present embodiment, since the end surface 632 of the anti-subtraction projection 63 extends below the edge 613 in the axial direction, the end surface 63 of the anti-subduction projection 63.
The overhang portion 261 of the DVD lens holding portion 26 comes into contact with 2 in the circumferential direction. Therefore, the rotation of the lens holder 2 can be reliably stopped. In this manner, the contact portion 72 can reliably prevent the lens holder 2 from turning too much in the direction of arrow B, regardless of the position of the lens holder 2 in the axial direction.

(Cover mounting structure) As described above, since the lens holder 2 is in contact with the cover 6, the cover 6 is subjected to an impact.
The cover 6 is attached to the yoke 4 as described below so that the cover 6 does not come off the yoke 4 or run idle.

As shown in FIG. 2, three mounting projections 44 to 46 are formed on the outer peripheral surface of the side plate 42 of the yoke 4, and the mounting portions 64 to 46 are formed in the cylindrical portion 62 of the cover 6.
66 are formed. The mounting projections 44 to 46
The cover 6 can be attached to the upper end 421 of the yoke 4 by fitting into the attachment openings 64-66. The protrusion amounts of the protrusions 44 to 46 are small, and the cylindrical portion 62 of the cover 6 is elastically deformed so that it can be attached to and detached from the yoke 4.

An engagement mechanism 10 is formed between the cover 6 and the yoke 4 so that the cover 6 does not rotate with respect to the yoke 4. The engagement mechanism 10 includes two engagement grooves 47 and 48 formed in the side plate 42 of the yoke 4,
There are provided two engagement projections 67 and 68 formed on the cover 6 so as to fit into the cover 7 and 48. The engagement grooves 47, 48
At a position at an angular interval of approximately 180 ° with respect to the axis L, the side plate 42 has a rectangular shape cut downward from the upper end edge. On the other hand, the engagement protrusions 67 and 68 project rectangularly downward from positions corresponding to the engagement grooves 47 and 48 of the cover 6. Therefore, even if the lens holder 2 hits the cover 6 in the circumferential direction, the cover 6 does not rotate with respect to the side plate 42.

(Effects of the Embodiment) As described above, the objective lens driving device 1 of the embodiment forms the stopper mechanism 7 between the lens holding portions 25 and 26 formed on the lens holder 2 and the cover 6. Therefore, the rotation allowable range of the lens holder 2 can be specified without providing the inner yoke. Therefore, it is possible to prevent the lens holder 2 from rotating more than necessary, and it is possible to prevent a problem such as the flexible printed board 19 from being twisted.

The cover 6 has an opening 611 cut out along the trajectory of the lens holders 25 and 26 as the lens holder 2 rotates, and the inner peripheral edge 61 of the opening 611.
The contact portions 71 and 72 with which the lens holding portions 25 and 26 abut in the circumferential direction by 2 and 613 are the inner peripheral edges 61 of the opening 611.
2, 613. As described above, the lens holding portions 25 and 26 formed on the lens holder 2 and the inner peripheral edges 612 and 61 of the opening 611 formed on the cover 6 are formed.
The stopper mechanism 7 can be realized with a simple configuration utilizing the third mechanism 3. Further, since the lens holding portions 25 and 26 hit the inner peripheral edges 612 and 613 of the opening 611, it is possible to reliably prevent the objective lens 2 from entering the lower surface of the cover 6.
Further, since the allowable rotation range of the lens holder 2 can be set relatively freely by changing the size of the opening 611 formed in the cover 6, it is easy to set the allowable rotation range of the lens holder 2 wide. .

Further, the lens holder 25 for CD and the DV
The D lens holder 26 is provided on the outer peripheral surface 21 of the lens holder 2.
A projecting portion 251 projecting radially outward from
261, and each of the contact portions 71 and 72 is
Since the lens holder 2 is provided with the anti-slipping protrusion 63 protruding downward from the cover 7 so as to be in contact with the lens holders 1 and 261, the lens holder 2 is located at a position (lower limit position) lowered away from the cover 6 and used for a CD. Lens holder 25 or D
The VD lens holding portion 26 has an inner peripheral edge 612 of the opening 611,
Even if it does not come into contact with the protrusion 613, the protrusion 63
Projecting portions 251 and 26 with respect to end surfaces 631 and 632 of
1 contacts. Therefore, regardless of the position of the lens holder 2 in the axial direction, the allowable rotation range of the lens holder 2 can be defined. In addition, the protrusion 63 for preventing sneaking in
Is formed radially outward of the outer peripheral surface 211 of the lens holder 2, so that it does not hinder the axial movement of the lens holder 2 even if it extends in the axial direction.

Further, between the cover 6 and the side plate 42,
Since the engagement mechanism 10 is configured to prevent the cover 6 from rotating relative to the side plate 42, an impact is applied to the cover 6 when the lens holding portions 25 and 26 hit the contact portion 72 of the cover 6. Even if it is applied, the impact causes the cover 6 to move the side plate 4
There is no deviation or deviation from 2.

(Other Embodiments) In the above embodiment, the lens holders 25 and 26 are used on the lens holder 2 side for the stopper mechanism 7, but the objective lenses 8 and 9 themselves are used. The protrusion on the holder side of the stopper mechanism 7 may be configured by utilizing the above. That is, the CD objective lens 8 and the DVD objective lens 9 are held in a state of projecting in the axial direction from the upper surface 231 of the lens holder 2 and project outward in the radial direction from the outer peripheral surface 211 of the lens holder 2. It has an overhang. The objective lenses 8, 9 are provided around the peripheral edges 612, 613 of the opening 611 formed in the cover 6 and the end face 6 of the anti-subduction projection 63.
By contacting the lens holders 31 and 632, the allowable rotation range of the lens holder 2 may be defined.

The stopper mechanism 7 can also be configured as follows. That is, of the outer end surface of the lens holder, an opening is formed in an upper end surface or a side end surface over an angle range corresponding to a rotation allowable range, while a contact portion protruding into the opening of the lens holder is provided on the fixed side member side. Is configured. With such a configuration, the contact portion of the fixed side member has
Since the inner peripheral edge of the opening of the lens holder rotating around the axis abuts, the rotation allowable limit position of the lens holder in this direction can be defined.

In the above embodiment, the objective lens driving device 1 having two objective lenses has been described. However, three or more objective lenses may be mounted. In addition, the invention may be applied to an objective lens driving device having only one objective lens when it is desired to extend the allowable rotation range of the lens holder.

Further, in the above embodiment, the plastic cover 6 is used.
Various materials such as metal and conductive plastic can be used.

Further, in the objective lens driving device 1 equipped with two objective lenses 8 and 9, the objective lenses 8 and 9
In order to prevent the objective lenses 8 and 9 from being inadvertently switched during the tracking correction, the rotation required for the tracking correction of the lens holder 2 is provided between the fixed member 5 and the lens holder 2. A stopper mechanism that defines only the allowable range may be formed.

For example, the objective lens driving device 1A shown in FIG. 4A is provided with a stopper mechanism 73. In this stopper mechanism 73, the cover 6 is provided on the cover 6 as shown in FIGS.
In addition to the contact portions 71 and 72 described with reference to FIG.
A contact portion 74 for preventing a malfunction in switching the lens position, which is bridged so as to cross in the radial direction, is formed.
In FIG. 4A, the same reference numerals are given to portions corresponding to the components described with reference to FIGS. 1 to 3, and description of those portions will be omitted.

The stopper mechanism 73 shown in FIG.
CD lens holder 2 formed on lens holder 2
5 (protruding part on the holder side) and DVD lens holding part 26
Utilizing the (holder-side protruding portion), the allowable rotation range of the lens holder 2 is defined even when any of the objective lenses 7 and 8 is used.

That is, as shown in FIG. 4A, when the lens holder 2 is at the angular position where the DVD objective lens 9 is used, the lens is located between the CD objective lens 8 and the DVD objective lens 9. A contact portion 74 for preventing position switching malfunction is located. On the other hand, as shown in FIG. 4B, when the lens holder 2 is at an angular position where the CD objective lens 8 is used, the CD objective lens 8 and D
A contact portion 74 for preventing a lens position switching malfunction is located at a position deviated from the space between the VD objective lens 9. As shown in FIG. 4C, the contact portion 74 is located at a position slightly higher than the contact portions 71 and 72 described with reference to FIGS. 1 to 3. And D
The VD lens holding portion 26 is located at such a height position as to abut.

Therefore, when the lens holder 2 is located at a height within a range in which the lens holder 2 moves by normal focusing correction,
When the lens holder 2 tries to rotate too much, the CD
The lens holding portion 25 (holder-side projection) and the DVD lens holding portion 26 (holder-side projection) abut against the contact portion 74, and further rotation is prevented. That is, FIG.
From the state shown in (A), the rotation of the lens holder 2 around the axis in the direction of the arrow A (the direction opposite to the lens switching direction) is as follows.
The rotation of the lens holder 2 around the axis in the direction of the arrow B (lens switching direction) is prevented by the contact of the CD lens holding portion 25 with the contact portion 74. Blocked by contact.
In addition, from the state shown in FIG. 4B, rotation of the lens holder 2 around the axis in the direction of the arrow B (the direction opposite to the lens switching direction) is performed when the DVD lens holding section 26 comes into contact with the contact section 72. Arrow A of the lens holder 2
The rotation about the axis in the (lens switching direction) is prevented by the contact of the CD lens holding portion 25 with the contact portion 74.

However, since the contact portion 74 is located at a position slightly higher than the contact portions 71 and 72, when the lens holder 2 rotates around the axis at the lower limit position in the axial direction, the CD is required.
Lens holder 25 and DVD lens holder 26
Does not come into contact with the contact portion 74 under the contact portion 74. Therefore, when the lens holder 2 rotates around the axis in the lens switching direction at the lower limit position in the axis direction, the stopper mechanism 73 allows this rotation. Therefore, in the objective lens driving device of the optical pickup, the lens positions of the objective lenses 8 and 9 can be switched.
In addition, the objective lenses 8 and 9 are carelessly
The lens holder 2 can be prevented from rotating as much as the switching is performed.

[0055]

As described above, in the objective lens driving device for an optical pickup according to the present invention, by utilizing the space between the fixed member and the outer end surface of the lens holder, the objective lens driving device around the axis of the lens holder with respect to the fixed member is used. Since the stopper mechanism that defines the allowable rotation range is configured, it is easy to extend the allowable rotation range of the lens holder in the stopper mechanism. That is, when the stopper mechanism is configured by using the inside of the lens holder, the inner yoke can move through the entire angle corresponding to the rotation allowable range inside the lens holder by the wide rotation allowable range. Since the hole is formed, a large restriction is imposed on the internal configuration of the lens holder. However, in the present invention, since the stopper mechanism is configured by using the space between the fixed-side member and the outer end surface of the lens holder, a great restriction is imposed on the configuration of the lens holder even when the rotation allowable range is set wide. Nothing.

[Brief description of the drawings]

1A and 1B are a plan view showing an objective lens driving device of an optical pickup to which the present invention is applied, and a cross-sectional view taken along line II ′.

FIG. 2 is an exploded perspective view of the objective lens driving device shown in FIG.

FIGS. 3 (A) and 3 (B) are explanatory diagrams each showing a state of defining a rotation angle in one rotation direction of a lens holder;
FIG. 9 is an explanatory diagram showing a state of defining a rotation angle of the lens holder in the other rotation direction.

FIGS. 4A and 4B are plan views each showing another form of an objective lens driving device, and FIG. 4C is a view II-A of FIG.
It is sectional drawing in the II 'line.

[Explanation of symbols]

 1, 1A Objective lens driving device 2 Lens holder 25 CD lens holder 26 DVD lens holder 211 Outer peripheral surface of lens holder 231 Upper surface of lens holder 251 Projection of lens holder for CD 261 Projection of lens holder for DVD Part 3 Slide shaft 4 Yoke 42 Side plate 47, 48 Engagement groove 421 Upper end 5 Fixed side member 6 Cover 61 Top plate 62 Cylindrical part 63 Projection for preventing sneaking-in 67, 68 Engagement projection 611 Opening 612, 613 Edge 631, 632 End surface of anti-subtraction projection 7, 73 Stopper mechanism 71, 72, 74 Contact part 8 Objective lens for CD 9 Objective lens for DVD 10 Engaging mechanism 11, 12 Tracking drive magnet 13, 14, Focusing drive magnet 15, 16, 17, 18 Drive coil L axis

Claims (9)

[Claims] 1. A lens holder for holding an objective lens in a lens holder, and a fixed member having a sliding shaft for supporting the lens holder, wherein the lens holder is attached to the fixed member. In contrast, in the objective lens driving device of the optical pickup supported so as to be movable in the axial direction of the sliding shaft and rotatable about the axis, the objective lens driving device may further include: a space between the fixed side member and an outer end surface of the lens holder. An objective lens driving device for an optical pickup, wherein a stopper mechanism for defining a permissible rotation range of the lens holder around the axis with respect to a fixed member is configured. 2. The holder mechanism according to claim 1, wherein the stopper mechanism includes the objective lens or the lens holding portion that projects upward from an upper end surface of an outer end surface of the lens holder on the lens holder side. A holder and a contact portion that contacts the holder-side protruding portion that rotates about the axis on the side of the fixed-side member and that defines a rotation allowable limit position of the lens holder in this direction. An objective lens driving device for an optical pickup, characterized in that: 3. The cover according to claim 2, wherein the contact portion is formed on a side plate surrounding the side end surface of the lens holder on the fixed side member so as to cover the lens holder. An objective lens driving device for an optical pickup. 4. The cover according to claim 3, wherein the cover has an opening cut out along a locus of the holder-side protruding portion accompanying rotation of the lens holder within the rotation allowable range. An objective lens driving device for an optical pickup, wherein the contact portion is constituted by a peripheral edge. 5. The lens holder according to claim 4, wherein the holder-side protruding portion includes a protruding portion that protrudes radially outward from a side end surface of the lens holder, and the abutting portion is larger than an outer end surface of the lens holder. Even when the lens holder is rotated about the axis at the lower limit position in the axial direction of the sliding shaft by projecting downward from the inner peripheral edge of the opening at a position on the radially outer side, the overhanging portion can be brought into contact with the lens holder to prevent dive. An objective lens driving device for an optical pickup, comprising a projection. 6. The method according to claim 3, wherein
An objective lens drive for an optical pickup, wherein the fixed side member has an engagement mechanism between the cover and the side plate for preventing the cover from rotating relative to the side plate. apparatus. 7. The stopper mechanism according to claim 1, wherein the stopper mechanism protrudes into the opening from an opening formed on an outer end surface of the lens holder over an angle range corresponding to the rotation allowable range, and from a side of the fixed side member. An inner peripheral edge of the opening that rotates around the axis to abut on the inner peripheral edge of the opening to define an allowable rotation position of the lens holder in this direction. Objective lens drive. 8. The method according to claim 1, wherein
The lens holder holds the two objective lenses in respective lens holding portions, and switches the relative positions of the two objective lenses with respect to the fixed side member by rotation of the lens holder around the axis. The stopper mechanism allows rotation of the lens holder around an axis in a lens switching direction for switching the positions of the two objective lenses, while the axis of the lens holder in a direction opposite to the lens switching direction. An objective lens driving device for an optical pickup, characterized in that the rotation of the objective lens is stopped within a predetermined angle range. 9. The lens holder according to claim 1, wherein the lens holder holds the two objective lenses in respective lens holders, and rotates the two lens units with respect to the fixed side member by rotating the lens holder around the axis. The relative position of the objective lenses is configured to be switched, and the stopper mechanism controls rotation of the lens holder around an axis in a direction opposite to a lens switching direction for switching the positions of the two objective lenses within a predetermined angle range. Stop at
Regarding the rotation of the lens holder around the axis in the lens switching direction, the lens holder allows rotation around the axis at the lower limit position in the axial direction of the lens holder, and the axis of the lens holder at a position above the lower limit position. An objective lens driving device for an optical pickup, characterized in that the rotation of the objective lens is stopped within a predetermined angle range.