JPH05210891A - Magneto-optical recording medium and recording method using this medium - Google Patents

Abstract

PURPOSE:To provide the recording medium having a rewriting characteristic and preservable property in combination by forming a magneto-optical recording film and a DRAW type recording film in this order on the side formed with tracks of a substrate formed with the tracks for guiding. CONSTITUTION:An optical disk 1 which is the optical recording medium is constituted by forming the tracks 2a for guiding a laser beam on the substrate 2 consisting of a transparent material and forming the rewritable magneto- optical recording film 3 consisting of a magneto-optical recording film and a dielectric film thereon. Further, the DRAW type optical recording film 4 is formed on the magneto-optical recording film 3. The surface of the DRAW type optical recording film is coated with a protective coating layer 5. As a result, both of magneto-optical recording and DRAW type recording are executed with one piece of the magneto-optical recording medium and, therefore, the information require to be rewritten is recorded on the magneto-optical recording film 3 and the information having the need to avert the destruction of data by an erroneous use in some cases is recorded on the DRAW type optical recording film 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium generally used in an external storage device such as a computer.

[0002]

2. Description of the Related Art An optical recording system records a signal on a recording film formed on a transparent substrate by using a light source such as a laser beam.
It is a system for reproducing, and is roughly classified into the following two systems.

One is a method of making holes in the recording film or changing the crystal structure by raising the temperature of the film on the substrate by irradiation with high-power light during recording. At the time of reproduction, the recording film is irradiated with low-power light to detect a change in the amount of reflected light from the recording portion. Among the optical recording media adopting the above method, one that cannot be rewritten is called a write-once optical recording medium.

The other is a method of applying an external magnetic field to the recording film whose temperature has been raised by irradiation of high-power light at the time of recording to reverse the magnetization direction of the part irradiated with light. A method to detect the presence or absence of recording by utilizing low-output light irradiation during reproduction and utilizing the phenomenon called the magnetic Kerr effect, in which the plane of polarization of light rotates depending on the direction of magnetization when light is reflected on the surface of a magnetic material. Take An optical recording medium that adopts this recording / reproducing system is called a rewritable optical recording medium.

For example, in FIG. 4, 1 standardized by ISO
An example of a 30 mm rewritable optical disc will be shown. In this example, the rewritable magneto-optical recording film 16 and the protective coat layer 17 are formed in this order on the track side of the substrate 15 and are laminated in the opposite direction via the adhesive layer 18 to form one optical disc. Is formed. A hub 19 for mounting the disc on a spindle motor (not shown) for rotating the disc is provided at the center of the disc.
・ 19 is provided on both sides.

Since these optical recording media use light, high-density recording is possible as compared with general magnetic recording media, and the portable recording medium has the characteristics of a hard disk and a floppy disk. Is widely used as an information recording medium.

[0007]

However, in the above-described write-once type optical recording medium, since information that has been recorded once cannot be erased, there is no risk of destruction of recorded information due to misuse, and fields where particularly storability is required such as medical applications are required. However, it is not suitable for general use because it cannot process files.

On the other hand, the rewritable type magneto-optical recording medium is promising as an information processing apparatus that makes use of the characteristics of a large capacity because it is erasable and rewritable and can be used as if it were a general magnetic recording medium. However, there is a problem that the risk of destruction of recorded information due to misuse is greater.

It is an object of the present invention to provide an optical recording medium which enables the above-mentioned two methods of recording on one sheet and has both rewritability and storability.

[0010]

In order to solve the above-mentioned problems, an optical recording medium according to the present invention comprises: a substrate on which guide tracks are formed;
It is characterized in that a magneto-optical recording film and a write-once type optical recording film are formed in this order.

When recording on the above-mentioned optical recording medium, when a magneto-optical recording film is used, laser light is irradiated from the substrate side,
When a write-once optical recording film is used, laser light is emitted from the side where the film is formed.

[0012]

With the above structure, recording / reproducing is performed using a magneto-optical recording medium for information requiring rewritability and recording is performed using a write-once optical recording film for information requiring storage. Playback can be performed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe one embodiment of the present invention with reference to FIGS.

An optical disc 1 which is an optical recording medium of this embodiment.
As shown in FIG. 1, a track 2a for guiding a laser beam is formed on a substrate 2 made of a transparent material such as glass or polycarbonate.
A rewritable magneto-optical recording film 3 composed of a magneto-optical recording film containing a rare earth transition metal and a dielectric film such as a metal nitride film is formed on the side where the track is formed, and further on the magneto-optical recording film 3. A write-once type optical recording film 4 made of a Te-based alloy material or the like is formed on. The write-once type optical recording film 4 is coated with a protective coating layer 5 made of a UV curable resin or the like on the film-forming surface thereof, and a spindle for rotation driving is provided at the center of the side of the optical disc 1 where the protective coating layer 5 is formed. A hub 6 mainly made of SUS-304 metal is attached for mounting on a hub (not shown).

When performing recording / reproducing on the optical disc 1 having the above-described structure, first, the optical disc 1 is mounted on the spindle motor of a recording / reproducing apparatus (not shown) via the hub 6.

When recording / reproducing is performed using the magneto-optical recording film 3 of the optical disk 1, when recording information,
The magneto-optical recording film 3 is irradiated with laser light from the laser light source 8 from the substrate 2 side, and the magnetic field is irradiated from the protective coat layer 5 side to the portion of the magneto-optical recording film 3 irradiated with laser light by the external magnetic field generator 7. Is applied. On the other hand, when the recorded information is reproduced, the laser light of the laser light source 8 is emitted and the information is read by utilizing the magnetic Kerr effect of the reflected light.

When recording / reproducing is performed using the write-once optical recording film 4 of the optical disc 1, when recording information, laser light is emitted from a laser light source 9 provided on the protective coat layer 5 side. Form pits according to information. When reproducing the information recorded in this way, laser light of low output is emitted from the laser light source 9 and read using the change in the amount of reflected light.

Incidentally, like the optical disc 10 shown in FIG.
The hub 6 may be provided on the substrate 2 side. In this case, the positions of the laser light source 8 for magneto-optical recording / reproducing, the external magnetic field generator 7 and the laser light source 9 for write-once optical recording / reproducing in the recording / reproducing apparatus are opposite to those in the case where the optical disc 1 is used.

Further, like the optical disc 11 shown in FIG.
The hubs 6 and 6 may be provided on both sides of the optical disk 11, respectively. In this case, it can be mounted on either side depending on the position of the laser light source of the recording / reproducing device or the external magnetic field generating device, so that versatility is expanded.

The present invention is not limited to the above embodiment, and an optical recording medium having another structure may be used as long as it has a magneto-optical recording film and a write-once optical recording film.

[0021]

As described above, in the optical recording medium according to the present invention, the magneto-optical recording film and the write-once type optical recording film are provided in this order on the track-formed side of the substrate on which the guide tracks are formed. It is the formed structure.

Therefore, since one magneto-optical recording medium can perform both magneto-optical recording and write-once recording, information that needs to be rewritten must be recorded on the magneto-optical recording film, and especially data destruction due to misuse must be avoided. Certain information can be recorded on the write-once type optical recording film, which has the effect of increasing the versatility of the optical recording medium.

Further, when manufacturing this optical recording medium, no special process is required as compared with the conventional one, so that a high value-added medium can be supplied without causing an increase in cost. Also effective.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing the structure of an optical disc of the present invention.

FIG. 2 is a vertical cross-sectional view showing the configuration of another optical disc of the present invention.

FIG. 3 is a vertical cross-sectional view showing the configuration of another optical disc of the present invention.

FIG. 4 is a vertical cross-sectional view showing the structure of a conventional magneto-optical disk.

[Explanation of symbols]

 1 optical disk (optical recording medium) 3 magneto-optical recording film 4 write-once optical recording film

Claims (2)

[Claims] 1. An optical recording medium, wherein a magneto-optical recording film and a write-once optical recording film are formed in this order on a track-formed side of a substrate on which guide tracks are formed. 2. A method of recording information on an optical recording medium in which a magneto-optical recording film and a write-once type optical recording film are formed in this order on the side where a track is formed in a substrate on which guide tracks are formed. Then, when the above-mentioned magneto-optical recording film is used, the laser beam is irradiated from the substrate side, and when the write-once optical recording film is used, the laser beam is irradiated from the side where the film is formed.