JP2555948B2 - Objective lens drive for optical disc - Google Patents

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 for an optical disk, and more particularly to irradiating a recording surface of a signal of an optical disk with light emitted from the outside through the objective lens and driving the optical disk from the recording surface of the optical disk. The present invention relates to an objective lens driving device for an optical disc, which is used as a part of an optical head that extracts reflected light through an objective lens and causes the objective lens of the optical head to follow the optical disc.

[0002]

2. Description of the Related Art An objective lens driving device (lens actuator) for an optical disk is a support capable of displacement driving for causing an objective lens for the optical disk to follow a focusing direction with respect to a surface shake of the optical disk and a tracking direction with respect to an eccentricity of the optical disk. A mechanism,
It has been conventionally incorporated and used as an indispensable component for an optical disk device.

5 to 6 show a conventional example of an objective lens driving device of this type. Here, FIG. 6 (A) is a partial plan view of the parallel link 34 shown in FIG. 5, and FIG. 6 (B) is a front view thereof.

In the conventional example shown in FIGS. 5 to 6,
The objective lens driving device is a plate-shaped actuator base 3
1 and one end is fixed to the actuator base 31 by a fixing pin 32, and the wide surface is formed on the actuator base 31.
Of the parallel link 34 parallel to the wide surface of the objective lens 3
The optical axis 6 of the actuator base 31 is maintained and held in a direction perpendicular to the wide surface of the actuator base 31, and the focus coil 38A,
38B and the track coils 41A, 41B, and a lens holder 37, and a central portion of the lens holder 37 is fixedly supported by one end and the other end is fixed by a fixing pin 32 to an upper surface which is a wide surface of the actuator base 31. In addition, the wide surface has a parallel link 34 whose parallel surface is parallel to the wide surface of the actuator base 31.

Further, this objective lens driving device is made of a magnetic material and has a rectangular parallelepiped outer shape, and one end thereof is fixed to the upper wide surface of the actuator base 31, and the wide surface is kept in a direction perpendicular to the wide surface of the actuator base 31. The yokes 42A and 42B are bent, and the wide surfaces of the yokes 43A and 43B are individually provided with the magnets 39A and 39B whose bottoms are fixed to the wide surfaces of the actuator base 31, respectively.

Of these, the yokes 42A and 42B are arranged at the centers of the air-core portions of the focus coils 38A and 38B, respectively, and the yokes 43A and 43B are provided at positions facing the outer surfaces of the track coils 41A and 41B. There is.

Further, the hinge mechanism 35 includes a hinge support portion 3
3 and a parallel link part (resin hinge) 34, and the parallel link part 34 extends from the hinge support part 33 in the direction of installing the lens.
The tip portion is supported so as to be movable in the vertical direction, that is, the focus direction. In addition, a leaf spring may be used instead of a hinge as a vertically movable support method.

A track hinge portion 35a is provided at the tip of the parallel link portion 34, and a lens holder 37 on which an objective lens 36 is placed rotates in the left-right direction, that is, the tracking direction, with the track hinge portion 35a as an axis center. Supported as possible. 6A and 6B are enlarged views of the parallel link portion 34 and the track hinge portion 35a.

As described above, the focus coil 3 is provided on both sides of the lens holder 37 equipped with the objective lens 36.
8A and 38B are equipped separately in two hands. Code 42
Reference numerals A and 42B denote yokes (iron cores) provided in the focus coils 38A and 38B, respectively. The focus coils 38A and 38B and the yokes (iron cores) 42A and 42
A pair of focusing follow-up adjusting means is constituted by B and is provided separately in two hands, whereby the objective lens 36 is movably adjusted in the focusing direction by following the surface wobbling of the optical disc as the medium. .

Further, focus coils 38A and 38B
Two track coils 41A and 41A are provided on the outer surface of the
Alternatively, 41B and 41B are fixed on the same surface at a predetermined interval, and magnets 39A and 39B and yokes 43A and 43B that support the magnets are arranged facing each other. The track coils 41A, 41B and the magnets 39A,
39B and the yokes 43A and 43B supporting them constitute a pair of tracking follow-up adjusting means, which are separately provided in two hands, whereby the objective lens 36 follows the eccentricity of the optical disc as the medium and in the tracking direction. It is designed to be movable.

In this case, although not shown in FIG. 5, optical blocks such as a laser diode and a polarization beam splitter are fixed to the lower surface of the actuator base 31, and the emitted light enters from the lower surface of the objective lens 36 and the objective The data of the medium can be read by the lens 36.

[0012] Here, Japanese Patent Laid-Open No. 62-026840 and Japanese Utility Model Laid-Open No. 63-044220 disclose the technology similar to the above. In all of these, use of a hinge utilizing a leaf spring is used. It is mainly composed of.

[0013]

However, in the above-mentioned conventional example, for example, in Japanese Patent Laid-Open No. 62-026840 and Japanese Utility Model Laid-Open No. 63-044220, the focus direction is movable up and down, so that it is used. There is a problem that the objective lens tilts and vibrates due to the occurrence of bending and twist peculiar to a thin and uniform hinge and leaf spring. Specifically, the torsion of the leaf spring causes the objective lens to roll, and the lens holder also causes a pitching phenomenon in which the objective lens vibrates in the vertical direction, which causes variations in the frequency characteristics and sensitivity of the entire device. However, there was a drawback that the reliability of the device was poor.

Further, in the conventional example shown in FIG. 5 which is adopted as an improvement of the above-mentioned conventional example, the parallel link 34 and the thin-walled hinge portion 35 are arranged at positions separated from each other, so that focusing is performed. Also, the drive center position of the drive unit during the adjustment drive for tracking and the objective lens drive center position are deviated. Therefore, in many cases, the control amount is deviated in the driving of focusing and tracking, which lowers the driving efficiency, and the parallel link 34 and the track hinge portion 35a are separated from each other, which causes a problem in component structure. It was difficult to downsize.

[0015]

An object of the present invention is to improve the inconvenience of the conventional example, and in particular, for an optical disk in which the objective lens is effectively and promptly controlled to follow the surface deflection or eccentricity of the optical disk and the entire apparatus is miniaturized. It is an object of the present invention to provide an objective lens driving device.

[0016]

SUMMARY OF THE INVENTION The present invention has a U-shaped body having a lens holding portion for holding an objective lens at the center of one end and a relatively large main body cutout portion extending from the center of the other end to the central portion of the main body. The lens holder body, and a biaxial hinge mechanism which is disposed in the body cutout portion of the lens holder body and supports the lens holder body at one end thereof via the lens holding portion.

Focusing, which is disposed on one side and the other side of the lens holder main body located on both sides of the biaxial hinge mechanism, adjusts the movement of the objective lens in the focusing direction by following the surface deflection of the optical disk. A follow-up adjusting unit and a tracking follow-up adjusting unit that is arranged in the vicinity of the focusing follow-up adjusting unit and moves and adjusts the objective lens in the tracking direction by following the eccentric movement of the optical disk are provided.

The biaxial hinge mechanism is provided in the central portion of the figure-eight hinge body having a predetermined thickness and arranged in the body excision along the lens holder body. A track hinge portion and a focus hinge portion set at a portion which forms each hollow region of the above-mentioned 8-shaped hinge main body with the track hinge portion interposed therebetween. Then, the center of gravity of the lens holder body provided with the objective lens is set so as to overlap the track hinge portion of the biaxial hinge mechanism, and the other end portion of the biaxial hinge mechanism is supported by the actuator base. There is. This aims to achieve the above-mentioned object.

[0019]

[Operation] First, when an optical disk, which is a medium, has a surface wobbling, the surface wobbling detecting means (not shown) detects this and immediately the focusing follow-up adjusting means 6 and 7 operate to follow the surface wobbling of this optical disk to move the objective lens 1. The equipped lens holder body 2 is movably adjusted in the focusing direction. In this case, focusing tracking adjusting means 6, 7
Is displaced in the direction of the focusing 12 so as to follow the objective lens 1 portion in accordance with the amount of surface wobbling, and the control amount is appropriately changed at any time so that the lens holder main body 2 does not cause arbitrary pitching. Is set.

When the optical disk, which is a medium, is eccentrically operated, it is detected by an eccentric operation detecting means (not shown), and the tracking follow-up adjusting means 8 and 9 are immediately activated,
Following the eccentric movement of the optical disc, the objective lens 1 portion of the lens holder main body 2 is displaced and driven (track hinge 4
Rotational drive along the optical disk surface with the part B as the central axis)
To do.

In this case, the tracking follow-up adjusting means 8,
In order to prevent the objective lens 1 from rolling in accordance with the amount of eccentric movement, the control amount 9 is appropriately variably controlled in cooperation with the above-mentioned focusing follow-up adjusting means 6 and 7 on both sides.

Further, focusing follow-up adjusting means 6, 7
And the adjustment control by the tracking follow-up adjusting means 8 and 9,
Since the center of gravity of the lens holder body 2 equipped with the objective lens 1 is set at the center of the biaxial hinge mechanism 4, the biaxial hinge mechanism 4 can follow the displacement of the optical disk surface.
It functions mainly in the central part of. Therefore, the displacement control amount can be made relatively small, and accordingly, the focusing follow-up adjusting means 6, 7 and the tracking follow-up adjusting means 8,
It is possible to reduce the displacement range of the lens holder main body 2 covered by 9 and, at this point, it is possible to downsize the entire apparatus, and at the same time, it is possible to follow the displacement of the optical disc surface with a small displacement control amount. Therefore, the follow-up control can be speeded up.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

1 to 3, reference numeral 1 indicates an objective lens, reference numeral 2 indicates a lens holder main body for holding the objective lens, and reference numeral 4 indicates a biaxial hinge mechanism.

The lens holder body 2 has a lens holding portion 2A for holding the objective lens 1 at the center of one end thereof,
It is composed of a U-shaped plate member having a relatively large main body cutout portion 2B extending from the center of the other end portion to the center portion of the main body. In addition, the biaxial hinge mechanism 4 is integrally formed of resin as a whole, and the main body cutout portion 2 of the lens holder main body 2 is formed.
The lens holder main body 2 is arranged in B and is configured to support the lens holder main body 2 at one end thereof via the lens holding portion 2A described above.

On one side and the other side 2a, 2b of the lens holder body 2 located on both sides of the biaxial hinge mechanism 4, the above-mentioned objective lens is moved in the focusing direction following the surface wobbling of the optical disk. Focusing follow-up adjustment means 6 and 7 for adjusting are provided, and tracking follow-up adjustment for moving and adjusting the objective lens 1 in the tracking direction by following the eccentric movement of the optical disk is provided in the vicinity of each focusing follow-up adjustment means 6 and 7. Means 8, 9 are equipped.

The biaxial hinge mechanism 4 comprises a lens holder body 2
8-shaped hinge main body 4A having a predetermined thickness, which is arranged in the main-body cut-out portion 2B, and a track hinge portion 4B provided at the central portion of the 8-shaped hinge main body 4A.
And focus hinge portions 4C and 4D (see FIG. 2) which are set in the portions forming the hollow regions of the above-mentioned figure-eight hinge main body 4A with the track hinge portion 4B interposed therebetween.

In addition, the focus hinge portions 4C and 4D
Specifically, as shown in FIG. 2B, the penetrating cutout portion formed along the longitudinal direction of the figure 8 hinge main body 4A at the center of the side wall of the figure 8 hinge main body 4A described above. 4a
Is formed on the cut surface portion of the.

The other end of the biaxial hinge mechanism 4 is fixed by an actuator base 11. Code 3
Shows a support pin for fixing the other end of the biaxial hinge mechanism 4 to the actuator base 11. Further, reference numeral 12 indicates a focusing direction with respect to surface wobbling of the optical disc, and reference numeral 13 indicates a tracking direction with respect to eccentricity of the optical disc.

Further, reference numeral 10 indicates a balancer which is provided at the opening end of the main body cutout portion 2B of the lens holder main body 2 to adjust the position of the center of gravity of the entire apparatus. With this balancer 10, the position of the center of gravity of the lens holder body 2 is adjusted to the biaxial hinge mechanism 4.
Is adjusted so as to be set on the track hinge portion 4B located in the central portion of or in the vicinity thereof.

Here, focusing follow-up adjusting means 6,
7 and the tracking follow-up adjusting means 8 and 9 will be described in more detail.

Focus coils 6A and 7A are separately provided on one side and the other side portions 2a and 2b of the lens holder body 2 equipped with the objective lens 1, respectively.
Reference numerals 6a and 7a denote yokes (iron cores) provided in the focus coils 6A and 7A, respectively. The focus coils 6A and 7A and the yokes (iron cores) 6a and 7a constitute a pair of focusing follow-up adjusting means 6 and 7, which are provided separately in two hands, and follow the surface wobbling of the optical disc as a medium. The objective lens 1 is movably adjusted in the focusing direction.

Two track coils 8A, 8A or 9 are provided on the outer surfaces of the focus coils 6A and 7A, respectively.
A and 9A are fixed on the same surface at a predetermined interval, and magnets 8B and 9B and yokes 8C and 9C that support the magnets 8B and 9B are arranged facing each other. This track coil 8
A and 9A, magnets 8B and 9B, and yokes 8C and 9C that support the magnets 8B and 9B constitute a pair of tracking follow-up adjusting means 8 and 9 and are provided separately in two hands. The objective lens 36 is movably adjusted in the tracking direction.

Here, the focus coils 6A, 7A forming part of the focusing follow-up adjusting means 6, 7 and the track coils 8A, 8A or 9A, 9A forming part of the tracking follow-up adjusting means 8, 9 are as described above. The lens holder body 2 is separately provided on one side and the other side portions 2a and 2b. In addition, yokes (iron cores) 6a and 7a forming a part of the focusing follow-up adjusting means 6 and 7 provided correspondingly, and the tracking follow-up adjusting means 8,
Magnets 8B and 9B forming a part of 9 and yokes 8C and 9C supporting them are fixedly mounted on the actuator base 11 described above.

In the focusing follow-up adjusting means 6 and 7 and the tracking follow-up adjusting means 8 and 9, the central portion of the output of each adjusting driving force is opposed to the track hinge portion of the above-mentioned figure 8 hinge body. It has been set to the position.

The biaxial hinge mechanism 4 will be described in more detail. This biaxial hinge mechanism 4 is a movable support mechanism in the focusing direction 12 and the tracking direction 13 with respect to the objective lens 1, and includes a track hinge portion 4B and a focus hinge portion 4C. 4D and its biaxial hinge 4
Resin-made hinge portions 4B, 4C, and 4D extend in the direction in which the objective lens 1 is installed from the two support pins 3 that are supported by.

The resin biaxial hinge mechanism 4 includes focus hinge portions 4C and 4D, which are one-side cutout hinges, so that the tip end portion of the biaxial hinge mechanism 4 can be moved in the vertical direction, that is, the focusing direction 12. The biaxial hinge mechanism 4
Are provided in the focusing direction 12 at the tip and in the vicinity of the supporting portion, respectively.

Track notch hinges 4B, which are notched hinges, are provided at the center positions on the diagonals of the tip end side and the support side of the focus hinge part in the focusing direction 12 above and below, respectively, and the objective lens 1 is mounted thereon. The lens holder body 2 is supported so as to be movable in the left-right direction, that is, the tracking direction 13 about the notched hinge portions. Then, the above-mentioned biaxial hinge mechanism 4
Is a track hinge portion 4B and a focus hinge portion 4C,
It is integrally molded with 4D arranged.

Next, the operation of the above embodiment will be described.

First, when an optical disk, which is a medium, has a surface wobbling, it is detected by a surface wobbling detecting means (not shown), and the focusing follow-up adjusting means 6 and 7 are immediately activated to follow the surface wobbling of the optical disk and mount the objective lens 1. The lens holder body 2 is moved and adjusted in the focusing direction. In this case, focusing tracking adjusting means 6, 7
Shows the objective lens 1 part in accordance with the amount of surface wobbling as shown in FIG.
As shown in (4), the lens 12 is displaced in the direction of the focusing 12 to follow it, and its control amount is appropriately variably set at any time so that the lens holder main body 2 does not freely pitch.

When the optical disk, which is a medium, is eccentrically operated, the eccentricity detecting means (not shown) detects it and immediately activates the tracking follow-up adjusting means 8 and 9,
Following the eccentric movement of the optical disc, the objective lens 1 portion of the lens holder body 2 is displacement driven (rotationally driven along the optical disc surface with the track hinge 4B portion as the central axis) as shown in FIG. 3 (A).

In this case, the tracking follow-up adjusting means 8,
In order to prevent the objective lens 1 from rolling in accordance with the amount of eccentric movement, the control amount 9 is appropriately variably controlled in cooperation with the above-mentioned focusing follow-up adjusting means 6 and 7 on both sides. Here, the operation of FIG. 3 is exaggerated for clarity.

Further, focusing follow-up adjusting means 6, 7
And the adjustment control by the tracking follow-up adjusting means 8 and 9,
Since the center of gravity of the lens holder body 2 equipped with the objective lens 1 is set at the center of the biaxial hinge mechanism 4, the biaxial hinge mechanism 4 can follow the displacement of the optical disk surface.
It functions mainly in the central part of. Therefore, the displacement control amount can be made relatively small, and accordingly, the focusing follow-up adjusting means 6, 7 and the tracking follow-up adjusting means 8,
It is possible to reduce the displacement range of the lens holder main body 2 covered by 9 and, at this point, it is possible to downsize the entire apparatus, and at the same time, it is possible to follow the displacement of the optical disc surface with a small displacement control amount. Therefore, the follow-up control can be speeded up.

Next, another embodiment will be described with reference to FIG.

The embodiment shown in FIG. 4 is characterized in that the biaxial hinge mechanism 4 of the embodiment shown in FIG. 1 is a biaxial hinge mechanism 24 constructed by using a wire. That is, the biaxial hinge mechanism 24 is provided between the wire supporting portions 24A and 24B arranged along the lens holder body 2 in the body cutting portion 2B and the wire supporting portions 24A and 24B. X over the upper and lower layers
It is composed of a plurality of (four in FIG. 4) elastic wires 24C that are connected and installed in a letter shape, and thereby can function almost the same as the above-mentioned biaxial hinge mechanism 4.

In the focusing follow-up adjusting means 6 and 7 and the tracking follow-up adjusting means 8 and 9, the central portion of the output of each adjusting driving force is the elastic wire 24 described above.
It is arranged at a position facing the intersection of C. The other structure is the same as that of the embodiment shown in FIG.

A case where the structure of the hinge 4 is realized by the wire 15 is shown in FIG. Although the wire 15 is provided as having the same function as that of the biaxial hinge 4 described above, the wire 15 extends from the support pin 3 to the objective lens 1 in the objective lens driving device.
Two wires 15 are installed in a crossed state in the extending direction, and the crossing position corresponds to the position of the track hinge 5 described above.

Further, the drive center position in the driving of the objective lens driving device in the tracking direction 13 and the focusing direction 12 in each of the above-described embodiments is set to coincide with the center of gravity of the objective lens driving device 14 described above.

Further, an optical block (not shown) is arranged around the objective lens driving device, and its emitted light is reflected by a reflection mirror (not shown) and then enters the objective lens 1, and the objective lens 1 The data on the optical disc is read by.

[0050]

Since the present invention is constructed and functions as described above, according to the present invention, the focusing follow-up adjusting means and the tracking follow-up adjusting means act to prevent the rolling, pitching and pitching of the lens holder main body which is an essential part of the apparatus. It is possible to effectively suppress the occurrence, and because the track hinge is installed in the center of the biaxial hinge mechanism and the center of gravity of the entire lens holder body including the objective lens is set to the center of the track hinge, it is less It is possible to efficiently drive the focusing direction with respect to the surface deviation of the optical disc and the driving in the tracking direction with respect to the eccentricity of the optical disc with a controlled amount without waste, and thus it is possible to downsize the focusing tracking adjusting means and the tracking tracking adjusting means. Therefore, it is possible to downsize the entire device. It is possible to provide a power sale excellent not in conventional objective lens driving device for an optical disk.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

2 shows a biaxial hinge mechanism which is a part of the embodiment disclosed in FIG. 1, FIG. 2 (A) is a plan view thereof, and FIG. 2 (B) is a front view thereof.

FIG. 3 is an explanatory diagram showing an example of the operation of FIG. 1, and FIG.
Shows the operation control state in the tracking direction with respect to the eccentricity of the optical disc, and FIG. 3B shows the operation control state in the focusing direction with respect to surface wobbling of the optical disc.

FIG. 4 is a perspective view showing another embodiment.

FIG. 5 is a plan view showing a conventional example.

6 shows a biaxial hinge mechanism which is a part of the conventional example disclosed in FIG. 5, FIG. 5 (A) is a plan view thereof, and FIG. 5 (B) is a front view thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Objective lens 2 Lens holder main body 2A Lens holding part 2a One side part of lens holder main body 2b Other side part of lens holder main body 2B Main body cutout part 4 Biaxial hinge mechanism 4A 8 shaped hinge main body 4B Track hinge part 4C , 4D Focus hinge part 6,7 Focusing tracking adjusting means 6A, 7A Focus coil 8,9 Tracking tracking adjusting means 8A, 9A Track coil 10 Balancer 11 Actuator base 12 Focusing direction 13 Tracking direction

Claims (4)

(57) [Claims] 1. A U-shaped lens holder main body having a lens holding portion for holding an objective lens at the center of one end thereof, and a relatively large main body cutout portion from the center of the other end to the central portion of the main body, and the lens. It is arranged in the main body cutting part of the holder main body,
A biaxial hinge mechanism that supports the lens holder body at one end thereof via the lens holding portion, and one side and the other side portions of the lens holder body portion located on both sides of the biaxial hinge mechanism. Focusing follow-up adjusting means for moving and adjusting the objective lens in the focusing direction by following the surface wobbling of the optical disk, and the focusing follow-up adjusting means arranged in the vicinity of the focusing follow-up adjusting means to follow the eccentric movement of the optical disk. A tracking follow-up adjusting means for adjusting the movement of the lens in the tracking direction is provided, and the biaxial hinge mechanism is arranged in the main body cutout along the lens holder main body and has a predetermined thickness. And a track hinge portion provided in the central portion of the figure-eight hinge main body, and the track hinge portion in between, And a focus hinge portion set in a portion forming each hollow region of the hinge body, and the center of gravity of the lens holder body including the objective lens is set to overlap with the track hinge portion of the biaxial hinge mechanism. In addition, the objective lens driving device for an optical disk is characterized in that the other end of the biaxial hinge mechanism is supported by an actuator base. 2. The focusing follow-up adjusting means and the tracking follow-up adjusting means are set such that the center portion of the output of each adjustment drive force is opposed to the track hinge portion of the figure-eight hinge main body. The objective lens driving device for an optical disk according to claim 1, wherein 3. A U-shaped lens holder main body having a lens holding portion for holding an objective lens for an optical disk at the center of one end thereof, and a relatively large main body cutout portion from the center of the other end to the central portion of the main body. The lens holder body is placed in the body cutting portion,
A biaxial hinge mechanism that supports the lens holder body at one end thereof via the lens holding portion, and one side and the other side portions of the lens holder body portion located on both sides of the biaxial hinge mechanism. Focusing follow-up adjusting means for moving and adjusting the objective lens in the focusing direction by following the surface wobbling of the optical disk and the focusing follow-up adjusting means arranged near the focusing follow-up adjusting means for following the eccentric movement of the optical disk. Tracking follow-up adjusting means for adjusting the movement of the lens in the tracking direction is provided, and the biaxial hinge mechanism includes one and the other wire supporting portions arranged in the main body cutout portion along the lens holder main body, and the wire supporting portion. X between the upper and lower layers
It is configured by a plurality of elastic wires connected in a letter shape, and the center of gravity position of the lens holder main body including the objective lens is set so as to be overlapped with the intersecting region of the elastic wires of the biaxial hinge mechanism, and An objective lens driving device for an optical disc, wherein the other end of the biaxial hinge mechanism is supported by an actuator base. 4. The focusing follow-up adjusting means and the tracking follow-up adjusting means are set such that the central part of the output of each adjustment driving force faces the intermediate part of the one wire supporting part and the other wire supporting part. The objective lens driving device for an optical disc according to claim 3, wherein