JPH03235238A - System of magneto-optical recording - Google Patents

Abstract

PURPOSE:To make improvement in data transfer rate by using an optical head corresponding to plural magnetic heads. CONSTITUTION:A magneto-optical disk 1 is subjected to recording, reproducing or erasing by using the optical head of multiple light beams corresponding to the plural small-sized magnetic heads 9, such as permanent magnets. The data transfer speed improves when the parallel magneto-optical recording, etc., are executed by combining the heads of every other track in order to prevent interference and crosstalks in this case. The effect thereof is additionally enhanced by the combination with the improvement in recording density, etc., by the utilization of bit edge recording and short wavelength light, etc.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to magneto-optical recording which is particularly effective in improving data transfer speed in a magnetic field modulation recording method using a plurality of laser beams and a plurality of externally applied magnetic field sources. Regarding the method of

[Conventional technology]

With the recent development of an advanced information society, high density.

The need for large-capacity file memory is increasing.

Optical memory is attracting attention as a memory that can meet this demand. Following compact discs, laser discs, and write-once optical discs, magneto-optical discs have been commercialized as rewritable optical discs in recent years. Research and development is currently underway to improve the performance of this magneto-optical disk.

One of these is an improvement in data transfer speed. One known method is to use a magnetic field modulation recording method and perform overwriting to increase the speed. As a known example, Japanese Patent Publication No. 60-48806 can be mentioned.

[Problem to be solved by the invention]

By the way, in the above-mentioned conventional technique, by enabling override by magnetic field modulation recording, the data transfer speed is reduced to 2/3 of that when using the conventional method.

In order to further increase the speed, methods such as increasing the number of rotations of the disk can be considered, but this poses a problem of destroying the recording medium of the magneto-optical disk due to a head crash. Therefore, increasing the data transfer speed without increasing the rotation speed has been an important issue for improving the performance of disks.

An object of the present invention is to provide a high-performance magneto-optical disk system by improving data transfer speed.

[Means to solve the problem]

The present invention provides a magneto-optical recording method that improves data transfer speed by accessing recording, reproducing, or erasing in parallel or simultaneously using multiple light sources and multiple externally applied magnetic field sources corresponding to the light sources. do.

An electromagnet can be used as an externally applied magnetic field source.

As the magnetic head, a floating magnetic head is particularly effective. Several tracks - every few tens of tracks.

In order to apply a magnetic field, it is necessary to provide magnetic field generation sources at intervals of several tens of micrometers to several hundreds of micrometers, but for this purpose, fine electromagnets can be manufactured by making full use of patterning technology and thin film formation technology.

The same applies to light sources, and by applying IC manufacturing technology, it is possible to integrally form a plurality of semiconductor laser light sources on the same Univer.

The important points when integrating optical heads and magnetic heads are:
Aligning the light source and the magnetic field is relatively easy if current semiconductor technology is applied. Here, unlike light, the externally applied magnetic field cannot be focused, so high precision is not required for the light source.

A plurality of heads may perform recording, reproducing, or erasing at the same time, or each head may perform independent access. Alternatively, they may be accessed in any appropriate combination, and these can be easily controlled by a head controller. However, it is often more efficient to have an optical head or magnetic head perform the same work.

Furthermore, as one of the applications of the present invention, a double-sided disk is used, in which two optical disks are assembled so that the recording media face each other and a space is created between the disks. Insert a magnetic head and access both sides of the disk at the same time. By doing so, the data transfer speed can be further improved compared to the case of a single-sided disk.

[Effect]

The present invention is a particularly effective technique for random access. High-speed recording is possible by appropriately performing recording using the head closest to the recording position of any one of the plurality of heads. In this case, you should be careful that
Regarding interference between pits and tracks, the light beam is irradiated not every other track, but every few tracks or every several tens of tracks, and the disk structure is of a thermal diffusion type with a metal layer on the surface. The thermal conductivity of this metal can be controlled, a structure without a metal layer, a two-layer structure consisting of a magneto-optical recording film and a Kerr enhancement film, or a single layer of a magneto-optical recording film can be selected as desired. This can prevent interference.

This is because the laser output during recording depends on the disk structure.

As described above, by combining a plurality of optical heads and magnetic heads,
By operating these simultaneously, the data transfer speed can be increased. Furthermore, by using a magnetic field modulation recording method that combines an optical head and a magnetic head, overriding becomes possible, so the data transfer speed can be further increased. It goes without saying that the same effect as above can be obtained even if a plurality of optical heads are used for optical modulation recording using an optical head. Furthermore, the gold track may be divided into parts as appropriate, and one head may be assigned to each part.

〔Example〕

Hereinafter, the details of the present invention will be explained using examples.

(Example 1) Fig. 1 shows a schematic diagram of the cross-sectional structure of an optical disc prototyped in this example. The recording medium was formed by sputtering on a plastic or glass substrate 1 having uneven guide grooves. First, a silicon nitride film was formed as the first dielectric film 2 to a thickness of 850 mm. Next, the magneto-optical recording film 3
As T b23F e,,Col,Nb,film 30
It was formed to have a film thickness of 0. Subsequently, a silicon nitride film was formed to a thickness of 200 mm as the second dielectric film 4, and AQ was formed as the metal film 5. Ti. Each film was formed to a thickness of 500 people. Finally, a protective coating layer 6 is applied using an ultraviolet curable resin.
was formed. The hardness after curing is required to be 3H or higher on the JIS pencil hardness scale.

Here, the effects of the present invention are not affected by the materials used for the first dielectric film 2 and the second dielectric film 3. Therefore, the materials used for these dielectric layers are not limited to silicon nitride, and may be any material that is chemically stable and has low optical absorption, such as aluminum nitride or silicon oxide.

However, the refractive index of the first dielectric film is 0 compared to the refractive index of the substrate.
．． It is desirable that the distance be 3 to 0.5 or more.

The same applies to magneto-optical recording materials, T b F
It is not limited to alloys of rare earth elements and iron group elements such as e Co N b, but also noble metal elements (Pt, P
d or Rh) and iron group elements (Fe.

Alternately laminated films with Co, Ni), alloys of light rare earth elements and iron group elements, alternately laminated films, etc. may be used. Since these materials have a large magneto-optical effect on short wavelength light, ultra-high-density recording can be performed, thereby further improving the performance of the disk.

Further, it is not affected by the disk structure, and may be a four-layer structure as in this embodiment, a three-layer structure, or a single layer structure.

A plurality of beams were irradiated onto the disk manufactured as described above, and magnetic heads were arranged in correspondence with the beams. Here, a flying magnetic head is used, and the flying distance is several μm to 1.5 μm. A micro magnet may be formed as a magnetic field generation source, or a thin film magnetic head with a patterned coil may be used.

FIG. 2 shows an example of the arrangement of tracks and heads.

In this example, three beams were concentrated and irradiated onto each land portion of three tracks, and a magnetic field of 300 to 4000 e was applied from a small thin film head to the corresponding position. In this case, the beam spacing or magnetic head spacing was approximately 100 μm. This interval may be any distance that does not cause interference between bits or tracks, and is set based on the disk structure, recording conditions, etc.

A 6 mW laser beam was irradiated as a light beam, and the magnetic field of the magnetic head was switched at high speed to perform recording. Each magnetic head may be operated independently or simultaneously. Alternatively, each person may be assigned a role such as recording and confirming records. In this way, when recording, reproducing, and erasing are performed using a plurality of heads and a plurality of magnetic heads, the access speed is reduced to less than half of the conventional speed, and performance is improved. Furthermore, since magnetic field modulation recording is used, it goes without saying that overrides are possible.

(Embodiment 2) FIG. 3 shows a magneto-optical disk according to another embodiment of the present invention.

In this embodiment, a magneto-optical disk is constructed by combining two disks such that the recording media face each other and a space is provided between the disks. A recording medium 8 having the same four-layer structure as before and having a protective coating on the surface is placed on the substrate 1.
Two disks were assembled using a magnetic hub 10 so that their medium surfaces faced each other. The hub 10 is provided with a ventilation hole 7 for creating a laminar air flow in the space surrounded by the disk when the disk rotates, and for stably floating a small thin-film magnetic head 9 inserted into the air. Also, the magnetic head 9.

A plurality of magnetic heads are formed so that they can access both disks at the same time, thereby shortening the access time.

Furthermore, multiple light beams 11 were provided on both sides of the disk. By adopting such a structure, in addition to simply increasing the storage capacity due to double-sided disks, it also became possible to perform high-speed access due to overriding, and high-speed access using multi-beams, resulting in higher performance of the disk. In this case, each of the plurality of heads may be assigned the roles of recording, confirming recording, and reproducing. Furthermore, in addition to higher performance such as increasing access speed by increasing the number of rotations of the disk and increasing the data transfer rate (access speed), we are also improving the recording density by using pit edge recording and short wavelength light. By combining this with improved performance, the range of uses for the disk becomes wider.

〔Effect of the invention〕

According to the present invention, by using a plurality of magnetic heads and a plurality of corresponding optical heads, data transfer can be performed in parallel or simultaneously using a plurality of heads, or by selecting a head, thereby increasing data transfer speed. can be improved. The present invention relates to access speed, and can improve the performance of a -layer optical disc by combining it with techniques such as improving recording density by pit-edge recording and the use of short wavelength light.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of an optical disk according to an embodiment of the present invention, FIG. 2 is a plan view showing the positional relationship between a plurality of light beams and a plurality of corresponding magnetic heads in an embodiment of the present invention, and FIG. The figure is a longitudinal sectional view showing a plurality of light beams and a plurality of magnetic heads corresponding to the light beams on a double-sided disk according to another embodiment of the present invention.

Claims (1)

[Claims] 1. In a magneto-optical recording method in which recording, reproduction, or erasing is performed on a magneto-optical recording medium using a laser beam and an externally applied magnetic field source, a plurality of light sources and a plurality of corresponding externally applied magnetic field sources are used. A magneto-optical recording method characterized by recording, reproducing or erasing on a magneto-optical disk using a magneto-optical disk. 2. In magneto-optical recording using a plurality of laser light sources and a plurality of corresponding externally applied magnetic field sources as described in claim 1, the plurality of externally applied magnetic field sources are simultaneously or independently magneto-optically recorded. A magneto-optical recording method characterized by recording, reproducing, or erasing information on a disk. 3. In magnetic field modulation recording in which recording, reproduction, or erasing is performed on a magneto-optical disk using a plurality of laser light sources and a plurality of externally applied magnetic field sources as described in claim 1, recording is performed on each head,
A magneto-optical recording system characterized by the role of playback and erasure. 4. A magneto-optical recording system characterized by using a component that integrates one or both of the plurality of light sources or the plurality of externally applied magnetic field sources according to claims 1 to 3.