JP3349714B2 - Magneto-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 a magneto-optical disk drive.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a conventional magneto-optical disk drive. In the figure, a magneto-optical disk 1
Is configured such that two substrates 12 on which a recording layer 11 is formed are fixed to, for example, a fixing member 13.

When information is recorded on the magneto-optical disk 1, a laser beam 2 is emitted from below. The emitted light is condensed by the objective lens 3 and is applied to the recording layer 11 via the lower substrate 12. Further, a magnetic field is applied to the recording layer 11 from the upper electromagnet 4, thereby recording information. When information is recorded on the recording layer 11 on the other side, the magneto-optical disk 1 is set upside down and information is recorded by the same operation.

In such a configuration, the distance from the electromagnet 4 to the recording layer 11 on which information is recorded is large. For this reason, the electromagnet 4 must output a strong magnetic field correspondingly. Therefore, the size of the electromagnet 4 is increased, and accordingly, the inductance of the coil is increased, so that the magnetic field cannot be modulated at a high frequency.

[0005] As a device capable of solving such inconvenience, there is a proposal disclosed in Japanese Patent Application Laid-Open No. 64-62850, for example. In this proposal, as shown in FIG. 4, a magneto-optical disk 1 has a recording layer 11 and a protective layer 1 on each surface of a substrate 12.
4 were formed respectively. When recording information, the laser beam 2 is irradiated from one opposing position on the disk surface to the recording layer 11 on the surface via the protective layer 14, while the laser beam 2 is distributed between the objective lens 3 and the magneto-optical disk 1. A predetermined magnetic field was applied by the provided coil 5.

According to this proposal, since the coil 5 is arranged near the recording layer 11 for recording information, the output magnetic field can be relatively low and can be formed small.

Now, for example, it is assumed that dust 6 of a certain size has adhered to the surface of the magneto-optical disk 1. In this case, as is apparent from a comparison between FIG. 3 and FIG. 4, in FIG. 4, the laser beam 2 is condensed on a minute spot and enters the protection layer 14 in a state of being condensed.
As a result, the amount of light that is shielded and reaches the recording layer 11 is greatly reduced, and an error in information recording and reproduction is likely to occur.

In order to prevent such adhesion of dust, it is conceivable that the device is provided with a dustproof structure. However, in that case, another disadvantage that the cost of the device is increased occurs.

[0009]

As described above, conventionally,
There is a problem in that miniaturization of the magnetic field applying component is liable to be adversely affected by dust.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magneto-optical disk drive which solves the above-mentioned problems, reduces the size of components for applying a magnetic field, and reduces adverse effects of dust.

[0011]

According to the present invention, a laser beam is emitted from a position facing one surface of a magneto-optical disk.
Irradiation is performed on the other recording layer via one recording layer, and a magnetic field is applied to the other recording layer from a position facing the other surface.

The laser beam incident on the magneto-optical disk has a large spot diameter on the disk surface, so that the adverse effect of dust is reduced. Further, since the magnetic field can be applied from a position close to the recording layer, the size of the magnetic field applying component can be reduced.

[0012]

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

FIG. 1 is a partial perspective view of a magneto-optical disk drive according to one embodiment of the present invention. In the figure, a magneto-optical disk 1 has a recording layer 15 on one surface of a substrate 12.
a and a protective layer 16a, and a recording layer 15b and a protective layer 16b on the other surface, each having a laminated structure.
The recording layer 15a is formed of a material that transmits laser light of a specific wavelength A and reflects laser light of another wavelength B. Further, the recording layer 15b is formed of a material that transmits the laser light of the other wavelength B and reflects the laser light of the upper specific wavelength A. Further, the protective layers 16a and 16b and the substrate 12 are formed of a material that transmits each of the laser beams.

Above the magneto-optical disk 1, a coil 7a
Is disposed, and an objective lens 8a is disposed further above. A coil 7b is provided below the magneto-optical disk 1.
Is provided, and further below the objective lens 8b is provided. The objective lenses 8a and 8b are each supported by an optical pickup device (not shown). The coils 7a and 7b are supported by those optical pickup devices or are supported by another supporting means.

In this configuration, for example, information is to be recorded on the recording layer 15b. In this case, the magneto-optical disk 1
Is emitted from above. The laser light 9a is condensed by the objective lens 8a, and passes through the protective layer 16a, the recording layer 15a, and the substrate 12 to form the recording layer 1a.
5b. At this time, the coil 7b is energized, and the output magnetic field acts on the recording layer 15b. Thus, information recording is performed. When reproducing recorded information, the recording layer 15b is similarly irradiated with laser light in a state where the coil 7b is not energized. Then, the reflected light from the recording layer 15b is detected by a light receiving means (not shown), and the recorded information is read.

On the other hand, when information is recorded on the recording layer 15a,
The laser light 9b having the wavelength B is emitted from below. The laser beam 9b is condensed by the objective lens 8b, and
6b, the recording layer 15b via the recording layer 15b and the substrate 12.
a. At this time, the coil 7a is energized, and the output magnetic field acts on the recording device 15a. Thereby, information recording is performed. When reproducing the recorded information, the recording layer 15a is irradiated with the laser beam in the same manner as described above in a state where the coil 7a is not energized, the reflected light is detected, and the recorded information is read.

By the way, it is assumed that dust 6 adheres to the protective layer 16a or 16b during such a recording / reproducing operation. In this case, the laser beam 9a or 9b is usually focused on a minute spot of about 1 μm at the position of the recording layer 15a or 15b, but at the position where it is incident on the protective layer 16a or 16b, the spot diameter is, for example, 1 mm. Very large like that. For this reason, the amount of light blocked by the dust 6 is small, and the recording / reproducing operation can be executed without error unless the dust 6 is particularly large.

In the above embodiment, the recording layers 15a, 1
5b is formed of a material that transmits one laser beam of wavelength A or B and reflects the other, but is formed of a material that transmits both wavelengths A and B, while protecting layer 16a transmits wavelength A. The same effect can be obtained by forming the protective layer 16b from a material that transmits the wavelength B and reflects the wavelength A while forming the protective layer 16b from a material that reflects the wavelength B.

Next, another embodiment of the magneto-optical disk 1 will be described.

In this embodiment, as shown in FIG. 2, the recording layers 15a and 15b of the magneto-optical disk 1 are formed on each surface of the substrate 12 only at track positions where information is recorded, that is, concentrically or spirally. Have been. In addition, the protective layer 1
6a and 16b are formed of a material that transmits both laser beams of wavelengths A and B, for example.

With this configuration, when recording or reproducing information, a laser beam 9 of the same wavelength is emitted from above or below. Then, the light emitted from above enters through the protective layer 16a, passes through the gap between the recording layers 15a, and forms a minute spot on the recording layer 15b. Light emitted from below enters through the protective layer 16b, passes through a gap between the recording layers 15b, and forms a minute spot on the recording layer 15a. Thereby, the recording and reproduction of the predetermined information is executed.

Here, it is assumed that dust 6 adheres to the surfaces of the protective layers 16a and 16b, for example. In this case, similarly to the above-described embodiment, since the spot diameter of the laser light is large at the surface position, the amount of laser light shielding is small, and the influence of the dust 6 is reduced.

In each of the above embodiments, the optical pickups are provided on both sides of the magneto-optical disk 1. However, the optical pickups are provided only on one side, and each surface is accessed by turning the magneto-optical disk 1 upside down. You may. When the configuration shown in FIG. 1 is adopted, the wavelength of the emitted laser light may be switched according to the surface to be accessed.

[0024]

As described above, according to the present invention, the laser beam is irradiated from one opposing position on the disk surface to the other recording layer via one recording layer.
On the disk surface, the spot diameter of the laser beam is large, so that the adverse effect of dust is reduced, and a magnetic field is applied to the other recording layer from a position opposite to the other surface. Since the magnetic field can be applied from the vicinity, the size of the magnetic field applying component can be reduced.

[Brief description of the drawings]

FIG. 1 is a partial perspective view of a magneto-optical disk drive according to one embodiment of the present invention.

FIG. 2 is a partial perspective view of a magneto-optical disk according to another embodiment.

FIG. 3 is a partial perspective view of a magneto-optical disk device according to a conventional example.

FIG. 4 is a partial perspective view of a magneto-optical disk device in another conventional example.

[Explanation of symbols]

 Reference Signs List 1 magneto-optical disk 8a, 8b objective lens 4 electromagnet 7a, 7b coil 15a, 15b recording layer 12 substrate 16a, 16b protective layer

────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Shuichi Honda 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Masahiko Nakayama 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Haruhiko Kono 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh Company (72) Takehide Ohno 1-3-6, Nakamagome, Ota-ku, Tokyo Stock Company Inside Ricoh Company (72) Inventor Takashi Ogawa 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh Company (56) References JP-A-63-220434 (JP, A) JP-A-3-173960 (JP, A) JP-A-2-156452 (JP, A) JP-A-61-208653 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 11/105

Claims (1)

(57) [Claims] 1. A magneto-optical disk device in which an objective lens and a magnetic field applying means are respectively arranged on both sides of a magneto-optical disk having recording layers provided on both sides of a transparent disk-shaped substrate, wherein the first surface of the magneto-optical disk is provided. A first objective lens facing the first recording layer provided on the second recording layer provided on the second surface of the magneto-optical disk through the first recording layer and the base; While focusing the first laser beam that performs the recording, reproducing, and erasing operations on the layer, the second objective lens facing the second recording layer transmits through the second recording layer and the base. Converging a second laser beam for recording, reproducing, and erasing the first recording layer, wherein the first objective lens and the second objective lens have their optical axes on the same straight line. And the recording of the first laser beam and First according to the erasing action
The first magnetic field applying means for generating the action magnetic field
Second magnetic field applying means disposed around the first objective lens and generating a second operating magnetic field in accordance with the recording and erasing operations of the second laser beam is disposed around the first objective lens. A magneto-optical disk device characterized by being provided.