JPS60212849A - Photomagnetic recording medium - Google Patents

Abstract

PURPOSE:To easily form not only a guide track but a magnetic film, by providing a magnetic layer having a vertical magnetic anisotropy and light transmitting property on a transparent or translucent substrate and further providing a guide track recording layer on the magnetic layer with a vacant space layer between them. CONSTITUTION:A magnetic layer 3 is formed on a transparent or translucent substrate 1' by sputtering, vacuum deposition, etc., and a guide track recording layer 2' made of a material which changes in color or melts and becomes porous and changes in the reflectance or transmittance upon receiving a laser light is formed on the magnetic layer 3 with a vacant space layer 5 between them. The vacant space layer 5 is formed by bonding the end sections of the magnetic layer 3 to the end sections of the guide track recording layer 2' with a spacer 6 between them and a protective layer 4 made of the material for making the transparent substrate is formed on the guide track recording layer 2'. Therefore, any complicated and expensive devices and processes used for forming the guide track in conventional methods are not required.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a magneto-optical recording medium having a guide track recording layer for guiding laser light.

PRIOR ART Magneto-optical recording media that perform recording and longevity using laser light, so-called magneto-optical memory disks, have a guide track layer for guiding laser light, for example, a plastic plate as shown in Fig. 1. ,
A guide track layer 2 consisting of minute grooves is formed by depositing an ultraviolet curable resin on a transparent substrate 1 such as a glass plate using a photoresist method, or a substrate with guide trunks is formed by injection molding, compression molding, etc. of plastic. year,
Thereon, a perpendicular magnetic anisotropic magnetic layer 3 such as a rare earth metal to transition metal amorphous alloy film (depending on the type of magnetic layer, a reflective film of metal or the like is provided and then a magnetic layer is provided) and the above-mentioned A device is known in which a protective layer 4 made of a material for a transparent substrate is provided. Recording and reproduction are performed by irradiating laser light from the substrate side. However, creating a guide track layer requires complicated and linear equipment and processes, and it is difficult to uniformly and centrally attach a magnetic film or reflective film to the micro grooves of the guide track layer formed in this way. was difficult.

Object The object of the present invention is to provide a magneto-optical recording medium that does not require complicated and expensive equipment or processes for forming guide tracks, and does not have problems in forming magnetic films or reflective films. The magneto-optical recording medium of the invention is made of a transparent or opaque substrate, a magnetic layer having perpendicular magnetic anisotropy and translucency, a gap layer, and a material whose reflectance or transmittance changes by being discolored or melted and perforated by laser light. The present invention is characterized in that it includes a guide track recording layer made of the above-mentioned material for a transparent substrate and an Li-retaining layer made of the above-mentioned transparent substrate material.

In this way, the magneto-optical recording medium of the present invention overcomes the drawbacks of conventional guide track layers by providing a guide track layer on a magnetic layer via a gap layer as a guide track recording layer that can record guide tracks with laser light. All have been removed.

The basic structure of the magneto-optical recording medium of the present invention is shown in FIG. In the figure, 1' is a transparent or opaque substrate, 2' is a guide track recording layer, 5 is a gap layer, and 6 is a spacer for forming the gap layer 5. Unlike the conventional method, recording and reproduction are performed by irradiating laser light from the protective layer 4 side.

Therefore, if the reflectance of the magnetic layer is low, a reflective layer 7 can be provided between the substrate and the magnetic layer as shown in FIG. In addition, in order to improve magneto-optical properties, a high refractive index transparent dielectric layer 8 may be provided between the magnetic layer and the substrate or between the magnetic layer and the gap layer as shown in @4[i: and FIG. I can do it.

Transparent substrates include general glass, quartz glass,
Inorganic materials such as crystallized glass, transparent ceramic, GGG single crystal, inorganic silicon, sapphire, lithium tantalate, etc., and opaque ones such as Ou, Affi, Ou-
AM, Cu-Zn, All-In-MP.

Metals or alloys such as Fe-0r, Fe-Ni-0u, Pi-Rh, etc. are used.

A reflective layer is provided when the reflectance of the substrate is low. Examples of materials used for the reflective layer include Ay, Au, and Ou.
, All, Pt, Or, Rh, Ni, My
, Zn, etc. Generally, methods such as sputtering, vacuum evaporation, and ion blasting are employed to form the layer, and the appropriate thickness is about 500 to 10,000×.

The magnetic material used for the magnetic layer is, for example, hexagonal ferrite λ(eMxFe12-)(01, (Me=Ba).

At least one of Pb, Sr, M = Ga, At,
Ti, Zn.

In, Sc, Mn, Co, Sn, Bi, S
At least one of m, V, Y, Cr, Ni, 0(
x(6); Co spinel ferrite OoMxFez-
)(04(M=Ae, Mn, Cr, Ni, Zn
.

Cu, Ga, In, Sc, Bi, Sm, Y
, V, Sn at least one value, 0(x(2) :Mn
bi-based PtMnSb; amorphous alloy magnetic material TbFe;
TbFe(Jd, TbFeCo, TbFeGdCo
.

TbFeDy0o, GdTbFe0o, GdFe,
DyFe, Gd0o.

(JdTbOo, GdFeB1 # may be mentioned. The layer formation method is the same as that for the reflective layer. The thickness is 01 to 1
Approximately 0 pm is appropriate.

The gap layer is formed by adhering the end of the magnetic layer and the end of the guide track recording layer via a spacer.

Plastic, glass, metal, etc. are used as the material for the spacer. Note that the spacer itself may be an adhesive. The thickness of the void layer is suitably about 01 to 100 μm.

Guide track recording ffj K is caused by the laser beam itself or its heat, (1) discoloration and change in reflectance, or (2) melt perforation to change transmittance (or reflectance, refractive index, etc., related to transmittance). Materials are used whose physical properties change (which may also be the case). Type (1) materials include chalcogenide materials, such as GeOx+TeOx, Te-C,
5eSb, 5eTe.

As5eSGe, 0eAsTe, MoOx, 5b
Ox, 5nOx, Te0xGeSn.

There are TeGe5bS, GeAsSe, 5ere, etc., and (2) type materials include metal 5e-Te,
Te, TeB1°TeAs, TeC3b53.
As25el, SeT'eSb, GeAsTe.

5eTeAs: Dyes such as phthalocyanine dyes, cyanine dyes, nigrosine dyes; plastics and plastics with metal powder dispersed therein are used. (In the case of material 11, as shown in Figure 6, the part irradiated with the laser light changes color (generally becomes black) as shown by 9,
For example, the reflectance R2 satisfies "+<"x +Rs. Furthermore, due to this change in reflectance, the transmittance and refractive index also change. For example, in the case of GeOx, when irradiated with semiconductor laser light with a wavelength of 800 nm, the transmittance changes from 80 cm to 2OL4. As for the formation method of such a guide track I-, when an inorganic material is used, it is generally the same as the reflective layer.
Methods such as ξ tuttering and vacuum evaporation are employed.

Among the aforementioned substrates, a transparent substrate is used for the protective layer. A suitable thickness of ViO is about 1 to 1 m+IW.

The material for the high refractive index transparent dielectric layer is Sin.

TiO2, Th01, CeO2, Si3N4, etc. are used. As a method for forming the layer, sputtering and vacuum evaporation methods are employed. Appropriate thickness is about 0.005 to 0.05 μm.

As can be understood from the above description, the magneto-optical recording body of the present invention has a guide track recording layer formed on the edge of the magnetic layer surface of a transparent or opaque substrate on which a magnetic layer (or a reflective layer and a magnetic layer) is previously provided. Adhering the provided transparent substrate (protective layer) to the edge of the recording layer surface via a spacer,
It is created by forming a void layer.

K for recording on the magneto-optical recorder obtained in this way is:
First, a semiconductor laser beam is irradiated in a groove shape from the surface of the protective layer to discolor or melt the material of the guide track recording layer in that area, thereby changing the transmittance of the recording layer. form the highest part of the

Next, a laser beam weaker than that used during guide track recording is guided along the guide track and irradiated from the surface of the protective layer in accordance with the information signal while applying an external magnetic field to the magnetic layer. is heated to the Curie temperature or compensation temperature, the magnetic moment is reversed,
Recording is thus performed. In addition, to reproduce this recorded signal, a laser beam weaker than that used when recording the information signal is similarly irradiated from the surface of the protective layer while being guided by a guide track, and after passing through the magnetic layer, the light reflected by the reflective layer is detected. It can be detected as an information signal using photons.

Effects As described above, since the magneto-optical recording medium of the present invention is provided with a guide track recording layer on the magnetic layer via the gap layer, in which guide tracks can be recorded or formed using laser light, conventional guide track formation is not possible. The complicated and expensive equipment and processes that have been used are no longer necessary, and the problems associated with forming magnetic or reflective films are also eliminated.

Examples of the present invention are shown below.

EXAMPLE After forming a reflective layer of 300× thickness by vapor depositing Ap on a quartz glass plate, Ba A11. oT i. .

13tojF'eloo19 f shatta! J 7f
A recording original plate A was prepared by providing a magnetic layer having a thickness of L and aoooX. On the other hand, a 0.5-thick polymethacrylic resin plate was used as a protective layer, and QeOx was sprinkled on top of it.
A guide track recording layer with a thickness of oooX is provided, and a recording original plate B is formed.
It was created. Next, the side edges of the ALD magnetic layer of the recording master plate and the side edges of the recording layer of the recording master plate B are machined. A void layer with a thickness of 0.1 pm was provided by adhering via a spacer made of resin adhesive.

An output of 15
rnW laser light with a frequency of 100KH.

A groove-shaped guide track was recorded on the recording layer by irradiating in a groove shape at a linear velocity of 0.3 m and 7 seconds.

Next, a semiconductor laser beam having an output of smw is guided through the guide track at a frequency of IMH and a linear velocity of 3 m, and is irradiated from the surface of the protective layer while applying an external magnetic field of 500 oersted to the magnetic layer. Information signals were recorded using this method. Also, the output of the recorded signal is 2m.
This was carried out by irradiating W laser light from the surface of the protective layer under the conditions of frequency I MH2 and linear velocity of 3 to 2 seconds.

Example 2 Cu was deposited on a polymethacrylic resin substrate by true nitrogen evaporation for 500 min.
A recording original plate A was prepared by providing a reflective layer with a thickness of X, and then sputtering KTbre magnetic material thereon to provide a magnetic layer with a thickness of 200X. On the other hand, a 1 m thick if'U methacrylic resin plate was used as a protective layer, and a cyanine dye was vacuum-deposited thereon to form a 1000× thick guide track recording layer, thereby producing a recording original plate B. Next, these recording original plates A and B were adhered via a spacer in the same manner as in Example 1 to obtain a magneto-optical recording medium.

Next, guide track recording, information signal recording, and information signal reproduction were performed on this recording medium under the following conditions.

Laser output (fiW) Frequency (MHz) Linear velocity (1 second) Guide trunk recording 7 0.5 0.5 Information signal recording 2]1 Information signal reproduction 1 3 3 Example 3 BaGa1. . Fl! 100+* was sputtered to form a magnetic layer with a thickness of 5000X, thereby producing a recording original plate A. On the other hand, a recording original plate B was prepared by using a 1 mm thick polycarbonate plate as a protective layer and sputtering Te01 thereon to form a 100 OX thick guide track recording layer. Next, these recording original plates A and B were used in Example 1.
Similarly, a magneto-optical recording medium was created by connecting to the port via a spacer.

Next, guide track recording, information signal recording, and 1*information signal reproduction were performed on this recording medium under the following conditions.

Laser power (fiW) Frequency (MHz) Linear speed (le seconds)
Guide track recording 10 0.3 0.5 Information signal recording 5 1 1 Information signal reproduction 2 3 3

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional magneto-optical recording medium, Fig. 2 is a basic block diagram of a magneto-optical recording medium of the present invention, Figs. 3 to 5 are modified views of the recording medium of Fig. 1, and Fig. 6 is FIG. 3 is an explanatory diagram when recording guide tracks on the magneto-optical recording medium of the present invention. 1...Transparent substrate 1'...Transparent or opaque substrate 2.
...Guide track layer 2'...Guide track recording layer 3...Magnetic layer 4...Protective layer 5...QSS 6...Spacer 7...Reflection 1-8...High refractive index Transparent dielectric layer 9...
Discolored part "I + "1 + R3... Laser light reflectance 1st
1 Part C: Diagram

Claims (1)

[Claims] 1. A magnetic layer having perpendicular magnetic anisotropy and translucency on a transparent or opaque substrate, a guide track recording layer made of a material whose reflectance or transmittance changes by being discolored or melted and perforated by laser light, and the transparent substrate. A magneto-optical recording medium that is sequentially provided with a protective layer made of a protective material.