JPH06215430A - Magneto-optical recording medium, magneto-optical recording device and magneto-optical recording method - Google Patents

Abstract

PURPOSE:To enable the execution of recording without requiring impression of external magnetic fields to the magneto-optical recording medium having a ROM part and a RAM part from its front and rear surfaces by enabling a user to form records in the ROM part as well and enabling the user to do such formation by arbitrarily selecting the material to be used for a recording film. CONSTITUTION:At least a first dielectric protective layer 2 and a recording layer 3 are laminated in this order on a transparent disk-shaped substrate 1. A reproduction only region laminated with a thermal diffusion layer 6 varying in the reflectivity measured from the recording layer 3 side from the reflectivity of the recording layer 3 and a reloadable region not laminated with this thermal diffusion layer are provided on the recording layer 3. Recording light output determination regions 20 consisting of the region laminated with the thermal diffusion layer and the region not laminated with the thermal diffusion layer are provided in the parts on the recording layer 3 which are not used for recording and reproducing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a read-only area (ROM
Part) and a rewritable area (RAM part), and records / reproduces / erases information by using laser light, a magneto-optical recording / reproducing device used for recording / reproducing of the magneto-optical recording medium, and The present invention relates to a magneto-optical recording method.

[0002]

2. Description of the Related Art Conventionally, prohibition of change of recorded contents on a magneto-optical disk has been performed by setting a write-inhibiting hole of a cartridge accommodating the disk into a write-inhibiting state.

[0003]

However, according to this method, the entire recorded content on the magneto-optical disk is prohibited from being changed, and only a part of the recorded content is prohibited from being changed, such as a document format portion or a dictionary portion. , In the case of frequently rewriting the recorded contents of other parts such as the document contents and the auxiliary registration dictionary, it was necessary to pay attention to the handling. Therefore, as described in JP-A-58-114343, there is proposed a magneto-optical recording medium in which a reflective film is provided on a ROM portion having pits on a substrate and a reproducing film for magneto-optical recording is provided on a RAM portion. In this case, since the ROM section and the RAM section have different reflectances, it is a burden on the recording / reproducing apparatus. Also R
Since the difference in reflectance between the OM portion and the RAM portion is limited to the range in which the recording / reproducing device can operate, it is impossible to arbitrarily select the material used for the recording film. Further, in order to manufacture the ROM section, it is necessary to provide ROM information on the board at the stage of molding the board, and the user cannot arbitrarily manufacture the ROM section.

As a means for solving such a problem, the present inventor has previously provided a magneto-optical recording medium having a magnetic shield layer (see Japanese Patent Application No. 4-227927) and a magnetic shield material as a magnetic shield plate. However, it is necessary to use a recording / reproducing apparatus equipped with means for applying an external magnetic field to both the light beam projecting side and the recording layer side, as proposed in Japanese Patent Application No. 4-227928. was there.

An object of the present invention is a magneto-optical recording medium having a ROM part and a RAM part, in which a user can create a record also in the ROM part and the material used for the recording film can be arbitrarily selected. The present invention provides a magneto-optical recording medium, a magneto-optical recording / reproducing apparatus, and a magneto-optical recording method that can perform recording without applying an external magnetic field from both front and back surfaces of the recording medium.

[0006]

In order to solve the above problems, according to the present invention, there is provided a magneto-optical recording medium in which at least a first dielectric protective layer and a recording layer are laminated in this order on a transparent disk-shaped substrate. The recording layer has a read-only area in which a thermal diffusion layer having a reflectance measured from the recording layer side different from that of the recording layer is laminated on the recording layer, and a rewritable area in which the thermal diffusion layer is not laminated. Provided is a magneto-optical recording medium having a recording light output determination region including a region where a thermal diffusion layer is laminated and a region where a thermal diffusion layer is not laminated in a portion not used for reproduction. Further, according to the present invention, there is provided a magneto-optical recording medium having the above-mentioned structure, wherein a second dielectric protective layer is provided between the recording layer and the thermal diffusion layer. Further, according to the present invention, in a magneto-optical recording medium in which at least a first dielectric protective layer, a recording layer, a second dielectric protective layer and a reflective layer are laminated in this order on a transparent disc substrate, the magneto-optical recording medium is provided on the reflective layer. In addition to having a read-only area in which a thermal diffusion layer having a reflectance measured from the recording layer side different from that of the recording layer is laminated and a rewritable area in which the thermal diffusion layer is not laminated, and which is not used for recording and reproduction on the reflective layer. There is provided a magneto-optical recording medium having a recording light output determination region including a region where a thermal diffusion layer is laminated on and a region where a thermal diffusion layer is not laminated. Further, according to the present invention, there is provided a magneto-optical recording medium having the above-mentioned structure, wherein a third dielectric protection layer is provided between the reflection layer and the heat diffusion layer. Further, according to the present invention, a means for applying an external magnetic field from the recording layer side to the recording layer side with respect to the magneto-optical recording medium, a means for projecting a light beam, and a reflected light of the light beam from the recording layer side. Provided is a magneto-optical recording / reproducing apparatus including means for detecting light reception and means for projecting a light beam with variable output on the substrate side. Further, according to the present invention, after confirming the recordable light beam output in each of the read-only area and the rewritable area with respect to the magneto-optical recording medium, when recording only in the rewritable area, A high power output that projects a low-output light beam that allows recording only in the rewritable area from the substrate side while applying a magnetic field, and can also record in the read-only area from the substrate side when recording in the read-only area. There is provided a magneto-optical recording method for projecting a light beam of

In the magneto-optical recording medium of the present invention, the material of the substrate is not particularly limited, but it is necessary that it is a transparent substrate. Specifically, in addition to inorganic materials such as glass, polymethyl methacrylate, polycarbonate, etc. , Polymer alloy of polycarbonate and polystyrene, epoxy resin,
Organic materials such as polyether sulfone, polysulfone, polyetherimide, and ethylene-tetracyclododecene copolymer can be used.

As the first dielectric protective layer, for example, SiO,
SiO ₂ , Si ₃ N ₄ or the like can be used. As the recording layer, a magneto-optical recording material such as TbFeCo, GdFeCo, Pt / Co multilayer film or the like can be used. As the heat diffusion layer, for example, a metal film of Al, Cu, Ag, Mo or the like, an alloy film thereof, or a laminated film can be used. The thermal diffusion layer needs to have a reflectance different from that of the recording layer when viewed from the recording layer side.

The location on the recording layer where the thermal diffusion layer is formed can be set arbitrarily. For example, the film is formed on the inner peripheral portion and the inner peripheral portion is used as a reproduction-only area; or conversely, it is formed on the outer peripheral portion. Then, the outer peripheral portion is set as the reproduction-only area; or alternatively, the film is alternately formed in the radial direction and the reproduction-only area and the rewritable area are set alternately.
Alternatively, it is possible to form a film on a specific sector on the disk and set the specific sector as a read-only area.

A second dielectric protective layer may be provided between the recording layer and the thermal diffusion layer, and the material for this layer may be SiO, SiO ₂ , Si ₃ O _4, etc. What was mentioned in the protective layer can be used. Furthermore, in a magneto-optical recording medium of the type in which a reflective layer is provided on the recording layer, a third dielectric protective layer may be provided between the reflective layer and the heat diffusion layer. As the material of the reflective layer, Al, Cr, or the like can be used, and the third dielectric protective layer is made of SiO, SiO ₂ , Si ₃ like the first dielectric protective layer and the second dielectric protective layer described above. O ₄ etc. can be used. According to such a magneto-optical recording medium, recording / reproducing can be performed by an apparatus provided with a means for applying an external magnetic field only on the recording layer side.

[0011]

The read-only area is provided with a thermal diffusion layer having a reflectance different from that of the recording layer so that the read-only area can be recognized, and the rewritable area (recording layer) can be recorded by stacking the thermal diffusion layers. To make it impossible to record in the read-only area with the light beam output that can be recorded in the rewritable area, and to record in both the read-only area and the rewritable area. This can be done by using a light beam output that can be recorded in the read-only area. Further, the required magnitude of the light beam output can be recognized in advance by the recording light output determination area including the thermal diffusion layer provided in the portion not related to recording and reproduction on the same surface and the portion not provided with the thermal diffusion layer.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings. 1 and 2 show an example of the magneto-optical recording medium of the present invention. 1 and 2, the first dielectric protective layer 2 and the recording layer 3 are laminated in this order on the transparent disk-shaped substrate 1, and the thermal diffusion layer 6 is laminated on the read-only area. In addition, in FIGS. 1 and 2, the recording light output determination region 2 including a region where the thermal diffusion layer 6 is laminated and a region where the thermal diffusion layer 6 is not laminated is shown.
0 is provided in the innermost circumference which is not used for recording and reproduction.
The recording light output determination area 20 may be provided at the outermost circumference. 1 and 2, the reproduction-only area is provided on the inner peripheral portion of the disc, but the reproduction-only area can be set at an arbitrary location and can be provided on the outer peripheral portion as shown in FIG. As shown in FIGS. 4 and 5, it is also possible to provide them alternately in the radial direction or the circumferential direction.

In the read-only area in which the thermal diffusion layer 6 is provided, the output of the light beam required to raise the temperature to the recordable level of the recording layer is larger than that in the rewritable area in which the thermal diffusion layer 6 is not provided. Therefore, if only the rewritable area is limited to an output that raises the temperature to a recordable level, information will not be erroneously written in the read-only area.

In FIG. 6, a second dielectric protection layer 4 is provided between the recording layer 3 and the thermal diffusion layer 6. Depending on the material of the recording layer 3, the Curie temperature and the compensation temperature are high, and the output of the light beam of the recording / reproducing apparatus may exceed the limit in recording in the read-only area. In the method of thinning the layer, there is a limit to the thinness due to the problem of the corrosion resistance of the thermal diffusion layer. Further, it becomes difficult to increase the difference in recordable temperature between the reproduction-only area and the rewritable area. Therefore, by providing the second dielectric protection layer 4 between the recording layer 3 and the thermal diffusion layer 6, it becomes possible to control the thermal diffusion, and only for reproduction without making the output of the light beam of the recording / reproducing apparatus excessive. Recording in the area can be performed.
Further, it becomes easy to increase the difference in recordable temperature between the reproduction-only area and the rewritable area.

7 and 8 show another example of the magneto-optical recording medium according to the present invention. In the figure, a first dielectric protective layer 2, a recording layer 3, a second dielectric protective layer 4, and a reflective layer 5 are laminated in this order on a transparent disc-shaped substrate 1, and a thermal diffusion layer 6 is provided in a read-only area. Are stacked. Further, a recording light output determination area 20 is provided in the innermost circumference in a portion where recording / reproduction is not performed. Also in this case, the output determination area 20 may be provided at the outermost circumference, as in the case of FIG. Further, it is also possible to provide the reproduction-only area not only in the inner peripheral portion but also in the outer peripheral portion or in any location in the radial direction and the circumferential direction alternately.
Is the same as in. Further, as shown in FIG. 9, a third dielectric protection layer 16 is provided between the reflection layer 5 and the heat diffusion layer 6,
Further, the operation when it is provided is the same as that in the case of FIG.

FIG. 10 shows a magneto-optical recording / reproducing apparatus using the above-mentioned magneto-optical recording medium, in which an objective lens 8 for passing emitted light 7 of a light-emitting element (not shown) to the substrate side of the magneto-optical recording medium A is provided. The magneto-optical recording medium A is provided with the light beam 9 condensed by the objective lens 8. On the recording layer side of the magneto-optical recording medium A, means 11 for applying an external magnetic field such as a permanent magnet or a coil is provided. Further, in order to recognize the read-only area in which the thermal diffusion layer is laminated and the rewritable area in which the thermal diffusion layer is not laminated, a light source 13 such as a semiconductor laser and a photodiode, a phototransistor, etc. are provided on the recording layer side of the magneto-optical recording medium A. The light receiving detection means 14 is integrally provided. Further, the light source 13 and the light receiving detection means 14 are movable in parallel to the substrate surface, and the direction of the light receiving portion of the light receiving detection means 14 is the light from the light source 13 reflected by the recording layer or the heat diffusion layer. Always faces in the direction of incidence. Therefore, it is possible to cause the magneto-optical recording / reproducing apparatus to recognize the position of the read-only area on the entire surface of the substrate by the difference in the intensity of the reflected light from the recording layer or the thermal diffusion layer and further store the position. Further, these means are arranged adjacent to the position where the light beam 9 is irradiated onto the magneto-optical recording medium A, and always recognize the presence or absence of the read-only area before the light beam 9 is irradiated onto the magneto-optical recording medium A. You may allow it. By the above method, the read-only area and the rewritable area can be recognized and recording / reproduction can be performed on the magneto-optical recording medium A.

Next, a case where the above-mentioned apparatus actually performs recording will be described. First, before recording, it is determined whether or not recording is performed in the read-only area, and the recording mode is selected according to the determination. Next, in order to determine the output of the light beam at the time of recording, while confirming the recording mark formation while changing the output in the recording light output determination area, the light beam output that enables recording in each of the read-only area and the rewritable area is determined. Recognize and memorize. When recording is performed in both the read-only area and the rewritable area, the output of the light beam is set to a size in which the read-only area can be recorded, and an external magnetic field is applied to perform thermomagnetic recording. When recording is performed only in the rewritable area, the output of the light beam is set to a size such that only the rewritable area can be recorded, an external magnetic field is applied, and thermomagnetic recording is performed.

The information recorded on the magneto-optical recording medium of the present invention can of course be reproduced by the conventional magneto-optical recording / reproducing apparatus, and there is no restriction on the reading of the information, and the read-only area can be obtained. If the thickness of the heat diffusion layer is set to a value that cannot be recorded by the light beam output of the conventional magneto-optical recording / reproducing apparatus, only the rewritable area can be recorded. Further, it is not necessary to manufacture the ROM part from the step of molding the substrate, the user of the magneto-optical recording medium of the present invention does not need the equipment for molding the substrate, and can manufacture the magneto-optical recording medium having the ROM part in a short period of time. can do.

[0017]

As described above, according to the present invention, the ROM
In a magneto-optical recording medium having a recording section and a RAM section, a user can also record in the ROM section, and this is performed by a recording / reproducing apparatus provided with an external magnetic field applying means only on the recording layer side of the magneto-optical recording medium. You can Further, for recording in the ROM portion, a means of providing a thermal diffusion layer on the recording layer of the magneto-optical recording medium is adopted, so that the material of the recording layer can be arbitrarily selected.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a magneto-optical recording medium of the present invention.

FIG. 2 is a plan view of the magneto-optical recording medium of FIG. 1 viewed from the recording layer side.

FIG. 3 is a plan view showing an example in which the position of a heat diffusion layer is different from that in FIG.

FIG. 4 is a plan view showing another example in which the position of the heat diffusion layer is different from that in FIG.

FIG. 5 is a plan view showing still another example in which the position of the heat diffusion layer is different from that in FIG.

FIG. 6 is a cross-sectional view showing another example of the magneto-optical recording medium of the type shown in FIG.

FIG. 7 is a cross-sectional view showing another example of the magneto-optical recording medium of the present invention.

8 is a plan view of the magneto-optical recording medium of FIG. 7 viewed from the recording layer side.

9 is a sectional view showing another example of the magneto-optical recording medium of the type shown in FIG.

FIG. 10 is a cross-sectional view showing the positional relationship between the main part of the magneto-optical recording / reproducing apparatus of the present invention and the magneto-optical recording medium.

[Explanation of symbols]

1 Substrate 2 First Dielectric Protective Layer 3 Recording Layer 4 Second Dielectric Protective Layer 5 Reflective Layer 6 Thermal Diffusion Layer 7 Light Emitted from Light Emitting Element 8 Objective Lens 9 Light Beam 11 External Magnetic Field Applying Means 13 Semiconductor Laser Light Source 14 Light Reception Detection Means 16 Third Dielectric Protective Layer 20 Recording Light Output Determination Area

Claims (6)

[Claims] 1. In a magneto-optical recording medium in which at least a first dielectric protective layer and a recording layer are laminated in this order on a transparent disk-shaped substrate, the reflectance measured from the recording layer side on the recording layer is the recording layer. And a rewritable area in which a thermal diffusion layer different from the above is laminated, and a rewritable area in which the thermal diffusion layer is not laminated, and an area in which a thermal diffusion layer is laminated in a portion of the recording layer not used for recording and reproduction and a thermal diffusion layer. A magneto-optical recording medium having a recording light output determination area which is an area not laminated with each other. 2. The magneto-optical recording medium according to claim 1, further comprising a second dielectric protection layer provided between the recording layer and the heat diffusion layer. 3. A magneto-optical recording medium in which at least a first dielectric protective layer, a recording layer, a second dielectric protective layer, and a reflective layer are laminated in this order on a transparent disk-shaped substrate, and recording is performed on the reflective layer. The reflectance measured from the layer side has a read-only area in which a thermal diffusion layer different from the recording layer is laminated and a rewritable area in which the thermal diffusion layer is not laminated, and the portion of the reflective layer not used for recording / reproduction is heated. A magneto-optical recording medium having a recording light output determination region including a region where a diffusion layer is laminated and a region where a thermal diffusion layer is not laminated. 4. The magneto-optical recording medium according to claim 3, wherein a third dielectric protection layer is provided between the reflection layer and the heat diffusion layer. 5. A means for applying an external magnetic field from the recording layer side to the recording layer side of the magneto-optical recording medium according to claim 1, a means for projecting a light beam, and a reflection of the light beam from the recording layer side. A magneto-optical recording / reproducing apparatus having means for receiving and detecting light, and means for projecting a light beam with variable output on the substrate side. 6. When recording is performed only in the rewritable area after confirming the recordable light beam output in each of the read-only area and the rewritable area in the magneto-optical recording medium according to claim 1. Applies a magnetic field to the substrate and projects a low-output light beam that can record only the rewritable area from the substrate side. When recording on the read-only area, the read-only area can also be recorded from the substrate side. A magneto-optical recording method for projecting a high-power light beam.