JP2705692B2 - Optical disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk apparatus for recording, reproducing and erasing information on an optical disk.

[0002]

2. Description of the Related Art In recent years, with the development of a highly information-oriented society, demand for high-density and large-capacity memories has been high, and one type of memory that meets this demand is an optical disk. Three types of optical disks have been put into practical use: a read-only type, a write-once type that can record only once, and a reversible type that can repeat recording / erasing many times.

When recording and erasing the optical disk with a conventional optical disk device, as shown in FIG. 5A, a laser beam from a fixed optical head (laser light source unit) 55 is applied to the optical disk 51. The necessary number of blocks are erased by the first rotation of the optical disk 51 by the carriage 52 having one optical system. Then, a three-rotation process of recording data as shown in FIG. 5B in the next one rotation and reproducing the data in the next one rotation is required.

Here, the structure of the carriage 52 will be described in more detail. As shown in FIG. 6, a lens actuator 31 having an objective lens 15 at one end is provided on the carriage 52. Lens actuator 3
1 includes a bobbin 31A having an objective lens 15, an arm spring mechanism 31B composed of four arm-shaped leaf springs, each of which is parallel to each other, an actuator body plate 31C holding the spring mechanism 31B, and this plate 31C. It comprises a leaf spring 31D to be held, and a fixed holder 31E fixed on the carriage 52 and holding the plate 31C via the leaf spring 31D.

[0005] A focus coil and a track coil (not shown) are wound around the bobbin 31A. Then, a pair of magnetic field generating means 32 and 33 facing the focus coil and the track coil are arranged on the carriage 52. With such a configuration, if the track coil is energized, the bobbin 31A can be driven in the disk radial direction T, and if the focus coil is energized, the bobbin 31A can be driven in the disk vertical direction F.

However, in the three-turn process described above,
It is difficult to handle large amounts of data efficiently. Also,
Demands for a verify function to check the contents immediately after recording data and an overwrite function to write new data while erasing recorded data are gradually increasing, and an optical disk device equipped with multiple laser beams has become increasingly popular. Has been requested. Therefore, in order to cope with such a demand, a method has been developed in which optical systems are independently provided on the two carriages 52 and 62 as shown in FIG. 7, and information is recorded and erased by one rotation of the disk. (For example, Japanese Patent Application Laid-Open No. 3-113758).

On the other hand, a magneto-optical disk has been put to practical use as a kind of the above-mentioned reversible optical disk. In an optical disk apparatus using this magneto-optical disk, a laser beam is focused on a disk surface by an objective lens to form a magnetic thin film on the disk. Is heated above the Curie point, and the direction of magnetization of the portion irradiated with the beam by the external bias magnetic field is directed to a desired direction to record and erase information. Therefore, formation of a bias magnetic field from the outside is an essential component.

In the example of FIG. 5 described above, an electromagnet 53 as bias magnetic field generating means is provided at a position facing the carriage 52 with the optical disk 51 interposed therebetween as shown in FIG. As described above, the electromagnet 54 must be provided on the carriage 52 as the bias magnetic field generating means. In addition, in the example of FIG. 7, electromagnets 53 and 63 as bias magnetic field generating means are provided at positions facing the carriages 52 and 62 with the optical disk 51 interposed therebetween.

[0009]

As described above, in the conventional optical disk apparatus, the number of magnetic field generating means for moving the objective lens in the direction perpendicular to the disk and in the radial direction of the disk is large, so that the carriage itself becomes large. However, there is a problem that the mounting space and weight of the carriage are increased, which hinders miniaturization and weight reduction of the optical disk device. Further, if the size of the magnetic field generating means is reduced in order to solve such a problem, there is a problem that a driving force required for moving the objective lens cannot be obtained.

A carriage having one optical system requires two rotations of a disk for erasing and recording information, which hinders high-speed processing of a large amount of data. Was. On the other hand, in a configuration having two carriages, information can be erased and recorded by one rotation of the disk. However, two drive mechanisms for the carriage are required. There was a point.

In the case where the bias magnetic field generating means is provided at a position facing the carriage with the optical disk interposed therebetween, the magnetic field intensity must be covered over the recording surface in the diameter direction of the optical disk. It was necessary to provide a mechanism for retracting the means, which hindered miniaturization of the apparatus.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its first object to provide an optical disk device capable of reducing the size and weight of the device. A second object is to process information recording and erasing at high speed.

[0013]

According to a first aspect of the present invention, a carriage, which is disposed opposite to an optical disk and held reciprocally from an outer peripheral portion to a center portion of the optical disk, has an elasticity. A plurality of objective lens supports elastically supported by the material and each including an objective lens, and a plurality of magnetic field generating means for moving each objective lens in the disk vertical direction and the disk radial direction, each objective lens support portion A part of the magnetic field generating means required for each pair is shared by a plurality of objective lens supports. By sharing a part of the magnetic field generating means with a plurality of objective lens supports, the number of magnetic field generating means can be reduced.

According to a second aspect of the present invention, two objective lens supports are provided as the objective lens support, and three magnetic field generators are provided as the magnetic field generator, and the first objective lens and the second objective lens are provided. The first magnetic field generating means is disposed between the first and second objective lenses, and the second magnetic field generating means is disposed on the opposite side of the first magnetic field generating means with the first objective lens interposed therebetween.
The third magnetic field generating means is arranged on the opposite side of the first magnetic field generating means with respect to the objective lens.

According to a third aspect of the present invention, one of the two objective lens supports is an erasure objective lens support corresponding to a laser beam for erasing information on the optical disk, and the other is an information storage medium for storing information on the optical disk. This is a recording objective lens support portion corresponding to a laser beam to be recorded. Further, one of the two objective lens supports is a recording objective lens support corresponding to a laser beam for recording information on the optical disk, and the other is a laser for reproducing information on the optical disk. This serves as a reproducing objective lens support portion corresponding to the beam. As described in claim 5, one of the two objective lens supports is an erasing objective lens support corresponding to a laser beam for erasing information on the optical disk, and the other is for recording and reproducing information on the optical disk. This is a recording / reproducing objective lens support portion corresponding to a laser beam.

According to a sixth aspect of the present invention, there is provided an erasing device for erasing information on an optical disk by a carriage which is arranged to face the optical disk and is movably reciprocated from an outer peripheral portion toward a center portion of the optical disk. Objective lens support with recording objective lens, recording objective lens support with recording objective lens for recording information on the optical disk, and moving each objective lens in the disk vertical direction and disk radial direction A plurality of magnetic field generating means for causing the object lens to be erased and the objective lens supporting means for recording to be arranged so that the objective lenses are arranged in parallel with the circumferential direction of the disk. Are arranged so as to face each other on both sides of the optical axis such that their polarities face each other. In this optical disk apparatus, information is erased and recorded by one rotation of the disk by two objective lens supports on one carriage. At this time, the bias magnetic field required for each of the information erasing and recording operations is generated by a magnetic field generating means for driving the objective lens.

According to a seventh aspect of the present invention, three magnetic field generating means are provided as the magnetic field generating means, and the first magnetic field generating means is disposed between the recording objective lens and the erasing objective lens. The second magnetic field generating means is disposed on the opposite side of the first magnetic field generating means with the erasing objective lens interposed therebetween, and the third magnetic field generating means is disposed on the opposite side of the first magnetic field generating means with the recording objective lens interposed therebetween. Is arranged.

According to the present invention, the erasing objective lens is formed by the first magnetic field generating means and the second magnetic field generating means, and leaks in a direction perpendicular to the disk surface at a position where the erasing objective lens faces. The intensity of the magnetic field is set to an intensity that satisfies the range of the bias magnetic field intensity required when erasing information from the optical disk, and is formed by the first magnetic field generating means and the third magnetic field generating means. The intensity of the magnetic field leaking in the direction perpendicular to the disk surface at the location is set to an intensity that satisfies the range of the bias magnetic field intensity required when recording information on the optical disk. According to a ninth aspect of the present invention, a permanent magnet is used as the magnetic field generating means.

[0019]

FIG. 1 is a plan view of a carriage of an optical disk apparatus showing a first embodiment of the present invention, FIG. 2 is a perspective view of the carriage, and FIG. 3 is a support for an objective lens provided on the carriage. FIG. 4 is an enlarged view of a bobbin serving as a part, and FIG. 4 is a diagram showing a state of generation of a bias magnetic field by magnetic field generating means on the carriage.

1 and 2, a carriage 2 is arranged on the lower surface of the optical disk 1 so as to face the optical disk 1, and the carriage 2 is held so as to be able to reciprocate from the outer periphery of the optical disk 1 toward the center. ing. The guide rails 3 and 4 hold the carriage 2 and
Guides you to reciprocate. On the carriage 2, an erasing lens actuator 11 having an erasing objective lens 5 for erasing information on the optical disc 1 at one end, and a recording objective lens 6 for recording information on the optical disc 1 at one end. And a recording lens actuator 12.

The erasing lens actuator 11 and the recording lens actuator 12 are arranged so that the objective lenses 5 and 6 are close to each other, and the objective lenses 5 and 6 are arranged in the circumferential direction of the optical disc 1 (in the tangent to the track). (Along the direction along) (ie,
(It is arranged in a direction orthogonal to the disk radial direction T which is the moving direction of the carriage 2).

Further, the erasing lens actuator 11
And the recording lens actuator 12 such that the two laser beams emitted from the fixed optical heads (laser light source units) 55 and 56 pass through the objective lenses 5 and 6 and enter the same track of the optical disc 1. Are located.

The erasing lens actuator 11 holds a bobbin 11A having an erasing objective lens 5, an arm spring mechanism 11B composed of four arm-shaped leaf springs which are parallel to each other, and holds the arm spring mechanism 11B. An actuator body plate 11C, a leaf spring 11D for holding the actuator body plate 11C, and a bobbin 1
1A, a spring mechanism 11B, and a plate 11C.
1D. The fixed holder 11E is fixed on the carriage 2.

The bobbin 11A, which is an objective lens support having the erasing objective lens 5, has a disk radial direction T at each of its upper and lower ends (focus direction F in FIG. 2).
The ends of the arm spring mechanism 11B are supported by one end of the arm spring mechanism 11B, and the other end of the arm spring mechanism 11B is supported by the actuator body plate 11C.

The actuator body plate 11
The leaf spring 11 </ b> D holding C is disposed in a direction parallel to the optical axis K <b> 1 of the erasing objective lens 5 and a surface thereof is orthogonal to the moving direction of the carriage 2. Due to the spring action of this leaf spring 11D, the actuator body plate 11C
Can reciprocate around the leaf spring 11D in a plane parallel to the rotation plane of the optical disc 1.

That is, the bobbin 11A can be moved in the disk vertical direction F by the arm spring mechanism 11B.
1D allows the disk to move in the radial direction T of the disk. Thus, the laser beam emitted from the objective lens 5 can be focused at an arbitrary position on the optical disc 1. The recording lens actuator 12 mounted in the opposite direction to the erasing lens actuator 11
It is configured exactly the same as the erasing lens actuator 11 and functions similarly.

That is, the recording lens actuator 1
Reference numeral 2 denotes a bobbin 12A provided with a recording objective lens 6, an arm spring mechanism 12B comprising four arm-shaped leaf springs which are parallel to each other, an actuator body plate 12C holding the arm spring mechanism 12B, Leaf spring 12D holding actuator body plate 12C
And a fixed holder 12E fixed on the carriage 2 and holding the plate 12C via a leaf spring 12D.

The bobbin 12A, which is an objective lens supporting portion provided with the recording objective lens 6, has both ends extending in the disk radial direction T at one of its upper and lower ends supported by one end of an arm spring mechanism 12B. Arm spring mechanism 12
The other end of B is supported by the actuator body plate 12C. The leaf spring 12D holding the actuator body plate 12C is connected to the optical axis K of the recording objective lens 6.
2 and the surface thereof is arranged in a direction perpendicular to the moving direction of the carriage 2.

That is, the bobbin 12A can be moved in the disk vertical direction F by the arm spring mechanism 12B.
It is configured to be movable in the disk radial direction T by 2D. Thus, the laser beam emitted from the objective lens 6 can be focused at an arbitrary position on the optical disc 1.

The bobbin 11A has a track coil 11a for driving the objective lens 5 in the disk radial direction T,
11b is attached to the side surface. Further, FIG.
As described above, a focus coil 11d for driving the objective lens 5 in the focus direction F is wound around a shaft (not shown) centered on the optical axis K1. The focus coil 11d, track coil 11a, 1
1b, a permanent magnet 2 as a pair of magnetic field generating means
1 and 22 are arranged on the carriage 2.

Similarly, the objective lens 6 is provided on the bobbin 12A.
The track coils 12a and 12b for driving the disc in the disk radial direction T are attached to the side surfaces thereof. Further, as shown in FIG. 3, a focus coil 12d for driving the objective lens 6 in the focus direction F is wound around a shaft (not shown) around the optical axis K2. In FIG. 3, the track coils 11a, 11b, 12a, and 12b are omitted to make the focus coil easier to see. And this focus coil 12d,
Permanent magnets 21 and 23 as a pair of magnetic field generating means facing the track coils 12 a and 12 b are arranged on the carriage 2.

Accordingly, the bobbins 11A and 12A share the permanent magnet 21 disposed between them. Three permanent magnets (or electromagnets) 21,
The reference numerals 22 and 23 are oppositely disposed on both sides of the optical axes K1 and K2 of the objective lenses 5 and 6 so that the polarities thereof are the same (see FIG. 4). When the permanent magnets 21 to 23 are arranged in this manner, the repulsion of the magnetic field causes leakage magnetic fields 21A and 21B having a magnetic flux density distribution as shown in FIG.

When the track coils 11a and 11b in the magnetic field generated by the permanent magnets 21 and 22 are energized, the bobbin 11A can be driven in the radial direction T of the disk. It can be driven in the direction F. Similarly, the permanent magnet 2
Track coil 12 in the magnetic field resulting from 1, 23
If power is supplied to the a and 12b, the bobbin 12A can be driven in the disk radial direction T. Similarly, if power is supplied to the focus coil 12d, the bobbin 12A can be driven in the disk vertical direction F.

In this manner, servo is performed in each of the focus and track directions based on the focus and track error signals obtained from the optical heads 55 and 56, and the laser beams from the objective lenses 5 and 6 are applied to the same track on the optical disc 1. To follow. With this configuration, the disk 1
The rotation enables erasure and recording of information.

Incidentally, a magnetic field 21 formed by the first permanent magnet 21 and the second permanent magnet 22 and leaking in a direction perpendicular to the disk surface at a position where the objective lens 5 faces.
The intensity of A is set to an intensity that satisfies the range of the bias magnetic field intensity required at the time of erasing. Also, the first permanent magnet 21
And the third permanent magnet 23, and the objective lens 6
The strength of the magnetic field 21B leaking in the direction perpendicular to the disk surface at the position where the magnetic field 21B faces is set to a strength that satisfies the range of the bias magnetic field strength required at the time of recording.

As described above, if the strength of the magnetic field of the permanent magnet is specified so that the strength of the leakage magnetic fields 21A and 21B can be maintained at the strength of the bias magnetic field required for predetermined erasing and recording, the objective lens can be driven. A part of the magnetic field generating means can be a bias magnetic field generating means.
The bias magnetic field strength of the optical disc 1 is generally 200 to 4
In the open type magnetic circuit shown in FIG. 4, the leakage magnetic field is large.
It is sufficiently possible to obtain a magnetic field strength of about 00 [Oe].

In this embodiment, the bobbins 11A,
The mechanism for supporting 12A has been described as a leaf spring.
Needless to say, the same effect can be obtained by the wire supporting method.

In this embodiment, the erasing lens actuator 11 and the recording lens actuator 12 are provided on the carriage 2, but the present invention is not limited to this. For example, a laser beam for reproducing information can be used. A reproduction lens actuator (reproduction objective lens support) and a recording lens actuator may be provided, or a recording / reproduction lens actuator (recording / reproduction objective lens support corresponding to a laser beam for recording and reproducing information). ) And an erasing lens actuator.

[0039]

According to the present invention, the number of magnetic field generating means can be reduced by sharing a part of the magnetic field generating means with a plurality of objective lens supports, as described in claims 1 and 2. The number of parts of the carriage can be reduced. Further, by equipping a plurality of objective lens supports on one carriage, only one carriage and its driving mechanism, which were conventionally required, become sufficient, and the structure and the number of parts can be significantly reduced in this respect. Can,
The overall occupied space by the carriage can be reduced. As a result, there is an effect that the mounting space and weight of the optical disk device can be reduced and the device can be reduced in size and weight. Further, since the carriage can be reduced in size without downsizing the magnetic field generating means, the disadvantage such as a reduction in driving force due to the downsizing of the magnetic field generating means does not occur.

Further, since the erasing objective lens support portion and the recording objective lens support portion are provided on one carriage, the information erasing operation and the recording operation can be performed by one rotation of the disk. And the processing speed can be increased. As a result, the speed of the overwriting process for writing new information while erasing the recorded information can be increased.

In addition, since the recording objective lens support portion and the reproduction objective lens support portion are provided on one carriage, the information recording operation and the reproduction operation can be performed by one rotation of the disk. And the processing speed can be increased. As a result, it is possible to speed up the verifying process for checking the contents immediately after recording the information.

Further, since the erasing objective lens support and the recording / reproducing objective lens support are provided on one carriage, the information erasing operation and the recording operation or the recording operation can be performed. The reproduction operation can be performed by one rotation of the disk, and the processing can be sped up. As a result, the speed of the overwrite processing and the verification processing can be increased.

Further, by arranging the magnetic field generating means on both sides of the optical axis of each objective lens so as to face each other with the same polarity, it is possible to erase and record information. Can be generated from the magnetic field generating means for driving the objective lens, and there is no need to provide a dedicated bias magnetic field generating means. Therefore, the number of components of the optical disk apparatus can be reduced, and the apparatus can be downsized. be able to. In addition, since it is not necessary to provide a bias magnetic field generating means on the carriage, the magnetic field from the bias magnetic field generating means affects the magnetic field generating means for driving the objective lens, causing a deterioration in servo characteristics and an increase in the weight of the carriage. The disadvantage that high-speed access is hindered does not occur.

[Brief description of the drawings]

FIG. 1 is a plan view of a carriage of an optical disk device according to a first embodiment of the present invention.

FIG. 2 is a perspective view of the carriage of FIG.

FIG. 3 is an enlarged view of a bobbin provided on the carriage of FIG. 1;

FIG. 4 is a diagram illustrating a state in which a bias magnetic field is generated by a magnetic field generating unit on the carriage in FIG. 1;

FIG. 5 is an explanatory diagram showing a case where information on an optical disc is erased by a conventional optical disc device, and an explanatory diagram showing a case where predetermined information is recorded on the optical disc.

FIG. 6 is a perspective view of a carriage of a conventional optical disc device.

FIG. 7 is an explanatory diagram showing a case where information on an optical disk is erased by another conventional optical disk device and a case where predetermined information is recorded on the optical disk.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... Carriage, 5 ... Objective lens for erasing, 6 ... Objective lens for recording, 11 ... Lens actuator for erasing, 12 ... Lens actuator for recording, 11
A, 12A: bobbin (objective lens support), 21 to 23
... permanent magnets (magnetic field generating means), K1, K2 ... optical axes of the objective lens.

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-263865 (JP, A) JP-A-3-296939 (JP, A) JP-A-63-304437 (JP, A)

Claims (9)

(57) [Claims] 1. A plurality of objective lens supporting portions, each of which is provided with an objective lens and is elastically supported by an elastic material and is provided on a carriage which is arranged to face the optical disk and is reciprocally movable from an outer peripheral portion to a center portion of the optical disk. And a plurality of magnetic field generating means for moving each objective lens in the direction perpendicular to the disk and in the radial direction of the disk. An optical disk device characterized in that the optical disk device is shared by a plurality of optical disks. 2. The optical disk device according to claim 1, further comprising: two objective lens supports as the objective lens support, and three magnetic field generators as the magnetic field generator. A first magnetic field generating means is arranged between the second objective lenses, and a second magnetic field generating means is arranged on the opposite side of the first magnetic field generating means with the first objective lens interposed therebetween, and An optical disc device comprising a third magnetic field generating means disposed on a side opposite to the first magnetic field generating means with a lens interposed therebetween. 3. The optical disk device according to claim 1, further comprising two objective lens supports as said objective lens support, wherein one of said two objective lens supports is a laser beam for erasing information on an optical disk. An optical disc device, comprising: a corresponding objective lens support for erasing; and the other an objective lens support for recording corresponding to a laser beam for recording information on an optical disc. 4. The optical disk device according to claim 1, further comprising two objective lens supports as said objective lens support, wherein one of said two objective lens supports is a laser beam for recording information on an optical disk. An optical disc device, comprising: a corresponding recording objective lens support portion; and the other is a reproduction objective lens support portion corresponding to a laser beam for reproducing information on the optical disc. 5. The optical disk device according to claim 1, further comprising two objective lens supports as said objective lens support, wherein one of said two objective lens supports is a laser beam for erasing information on an optical disk. An optical disc device, comprising: a corresponding objective lens support for erasing; and the other an objective lens support for recording / reproducing corresponding to a laser beam for recording / reproducing information on the optical disc. 6. An erasing objective comprising an erasing objective lens for erasing information on an optical disc, on a carriage arranged opposite to the optical disc and held reciprocally from the outer periphery to the center of the optical disc. A lens support portion, a recording objective lens support portion having a recording objective lens for recording information on an optical disc, and a plurality of magnetic field generating means for moving each objective lens in a direction perpendicular to the disc and in a radial direction of the disc. The objective lens support for erasing and the objective lens support for recording are arranged so that the objective lenses are arranged in parallel in the disk circumferential direction, and the magnetic field generating means is provided on both sides of the optical axis of each objective lens. An optical disk device characterized in that the optical disk device is arranged so as to face each other with the same polarity. 7. The optical disk device according to claim 6, further comprising three magnetic field generating means as said magnetic field generating means,
A first magnetic field generating means is disposed between the recording objective lens and the erasing objective lens, and the first magnetic field generating means is disposed between the recording objective lens and the erasing objective lens.
An optical disk, wherein a second magnetic field generating means is arranged on the opposite side of the magnetic field generating means, and a third magnetic field generating means is arranged on the opposite side of the first magnetic field generating means with the recording objective lens interposed therebetween. apparatus. 8. The optical disk device according to claim 7, wherein the first magnetic field generating means and the second magnetic field generating means leak in a direction perpendicular to a disk surface where the erasing objective lens faces. The intensity of the generated magnetic field is set to an intensity that satisfies the range of the bias magnetic field intensity required when erasing information from the optical disk.
The intensity of the magnetic field that is formed by the magnetic field generating means and leaks in the direction perpendicular to the disk surface at the position where the recording objective lens faces, satisfies the range of the bias magnetic field intensity required when recording information on the optical disk. An optical disk device characterized by being set to: 9. The optical disk device according to claim 1, wherein a permanent magnet is used as said magnetic field generating means.