JP2996261B2 - Information recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite information recording medium in which an optical information recording layer and a magnetic information recording layer are laminated on one transparent substrate.

[0002]

2. Description of the Related Art Hitherto, optical recording media for recording and / or reproducing information by optical means, such as a compact disk (CD), a video disk (VD), and an optical disk memory for a computer, are known. . This optical recording medium includes a read-only optical recording medium such as a CD and a VD, a write-once type optical recording medium such as a perforated type in which information can be added only once, and a magneto-optical type. There is an erasing type optical recording medium which can repeatedly record and erase information such as a phase change type.
Magnetic recording media for recording and reproducing information by magnetic means, such as floppy disks and hard disks, have also been widely known.

[0003]

An optical recording medium can have a much higher areal recording density than a magnetic recording medium, but on the other hand, the recording film or reflective film constituting the information recording layer is corroded. If the recording film or the reflective film is not covered with a strong protective film, the recording / reproducing characteristics are likely to deteriorate in a short period of time. In particular, a magneto-optical recording medium having a recording film made of a magneto-optical recording material that magnetically records information using the Kerr effect or the Faraday effect and optically reproduces the recorded information has a corrosion-resistant recording film. Therefore, the recording film cannot be put to practical use without being covered with a strong protective film.

In addition, unlike a magnetic recording medium, it is difficult to provide a recording layer on both the front and back surfaces of a single substrate, and an optical recording medium has a single-sided recording medium. It is necessary to adopt a structure in which two transparent substrates on which one information recording layer is formed are bonded concentrically with the information recording layer inside, and the information recording medium becomes complicated and large, and the There is a disadvantage that the cost is high.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a composite information recording medium having a high recording density, excellent long-term storage properties, a simple structure, and inexpensive manufacture. With the goal.

[0006]

In order to achieve the above object, the present invention provides a transparent substrate, a first information recording layer on which information can be recorded / reproduced by optical means, and a method of recording information by magnetic means. A second information recording layer capable of recording and reproduction, and a first preformat pattern from which signals can be read by optical means provided at an interface between the transparent substrate and the first information recording layer; At the interface between the first information recording layer and the second information recording layer, a second preformat pattern from which a signal can be read by optical means is provided.
And the second preformat pattern is arranged so as to be shifted from each other in the plane direction of the transparent substrate.

This information recording medium comprises an optical head for recording and reproducing information on and from the first information recording layer, and a magnetic head for recording and reproducing information on and from the second information recording layer. When recording / reproducing information on / from the second information recording layer, the magnetic head is not operated alone, but is always operated in a state of maintaining a fixed positional relationship with the optical head. It can be driven by a drive device.

[0008]

The magnetic recording film is generally excellent in chemical stability and can be stored for a long time while being exposed to the air. Therefore, when this magnetic recording film is coated on a recording film or a reflective film constituting an information recording layer of an optical recording medium in place of a conventional protective film, it has excellent long-term storability with almost no increase in manufacturing cost, and An information recording medium in which two information recording layers are formed on one transparent substrate can be configured.

A first preformat pattern from which signals can be read by optical means is provided at the interface between the transparent substrate and the first information recording layer, and the first information recording layer and the second information recording layer are provided. When a second preformat pattern from which a signal can be read by optical means is provided also at the interface with the layer, and these first and second preformat patterns are arranged so as to be shifted from each other in the plane direction of the transparent substrate,
By positioning the laser beam emitted from the optical head in the first preformat pattern, an address signal or a recorded information signal preformatted on the transparent substrate can be read. By irradiating a desired address read in this manner with a recording laser beam spot, information can be additionally recorded. Further, by positioning the laser beam emitted from the optical head on the second preformat pattern, an information signal preformatted on the first information recording layer can be read. In addition, by driving the magnetic head, it is possible to record and reproduce information on and from the second information recording layer. Therefore, according to the present invention, an information recording medium having a total of three information recording layers on one transparent substrate can be obtained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 is a cross-sectional view of a main part of the information recording medium according to the present example, FIG. 2 is a plan view of the information recording medium according to the present example, FIG. 3 is a partially enlarged plan view of the information recording medium according to the present example, and FIG. FIG. 5 is a diagram illustrating a manufacturing process of the information recording medium according to the present embodiment, FIG. 5 is an explanatory diagram of a drive device for recording and reproducing information by mounting the information recording medium according to the present embodiment, and FIG. 6 is an explanatory diagram illustrating a method of recording and reproducing information. It is.

As shown in FIG. 1, the information recording medium 1 of the present embodiment
Is a transparent substrate 2 having a first preformat pattern 3 formed on one side, and a second preformat carried on a surface of the transparent substrate 2 on which the preformat pattern 3 is formed and not in contact with the transparent substrate 2. A first preformat pattern comprises an organic dye film 32 having a pattern 31 formed thereon, a reflective film 4 stacked on the organic dye film 32, and a magnetic recording film 5 stacked on the reflective film 4. 3, an organic dye film 31, and a reflective film 4 constitute a first information recording layer, and the magnetic recording film 5 constitutes a second information recording layer.

The transparent substrate 2 is made of, for example, a transparent ceramic material such as glass, or a transparent plastic material such as polycarbonate, polymethyl methacrylate, polymethyl pentene, epoxy, or a photocurable resin. It is formed in a disk shape having a desired diameter and having a hole 2a.

The first preformat pattern 3 represents, for example, a tracking servo signal for guiding an optical head for optically reading a signal from the preformat pattern 3 along a predetermined track, an address of each track, a reference clock, and the like. A header signal, an information signal, and the like are formed on one surface of the transparent substrate 2 in the form of fine irregularities. In the example of FIG. 3, a pre-pit row 7 representing a header signal and a pre-pit row 8 representing an information signal are formed on a guide groove 6 for providing a tracking servo signal. In addition,
The configuration of the preformat pattern 3 is not limited to the configuration shown in FIG. 3, but can be configured in the same manner as the preformat pattern formed on the CD. Also, it is possible to preformat only a signal necessary for guiding the optical head, such as a tracking servo signal, without including an information signal. In any case, the first preformat pattern 3 is formed in a spiral shape or concentric shape with the center hole 2a as shown in FIG.

In the case of the configuration shown in FIG. 3, the guide groove 6 and the pre-pits 7, 8 are formed at different depths from each other in order to give a contrast to the intensity of the reflected light when the reproduction light is irradiated. You. For example, the guide groove 6 has a wavelength of the reproducing light of λ and a refractive index of the transparent substrate 11 of n.
In this case, the pre-pits 7 and 8 are formed at a depth of λ / 4n to λ / 6n. That is, when the guide groove 6 or the portion where the pre-pits 7 and 8 are located is irradiated with the reproduction light, the intensity of the reflected light decreases due to interference and diffraction of the light. On the other hand, when the light for reproduction is irradiated to a portion where the guide groove 6 and the pre-pits 7 and 8 are not present, a phenomenon such as light interference and diffraction does not occur, and the reflected light intensity does not decrease. Therefore, the presence or absence of the guide groove and the pre-pit can be detected by detecting the intensity of the reflected light from the information recording medium 1 with the photodetector. Also, since the guide groove 6 and the pre-pits 7 and 8 have different reflected light intensities due to the difference in their depths,
Can be identified.

The first preformat pattern 3 is formed by an appropriate method according to the material of the transparent substrate 2. For example, when the transparent substrate 2 is formed of a thermoplastic resin such as polycarbonate, polymethyl methacrylate, and polymethyl pentene, the molten substrate material is injected into a molding die, and the transparent substrate 2 having the preformat pattern 3 is formed. A so-called injection method for forming the substrate 2 is suitable. Further, a so-called compression method or an injection-compression method in which pressure is applied after injecting the substrate material into the mold, or the like can be applied. Further, when the transparent substrate 2 is formed of a transparent ceramic material such as glass or a thermosetting resin such as an epoxy resin, for example, the transparent substrate 2 is formed between the stamper on which the inverted pattern of the preformat pattern is formed and the transparent substrate 2. The so-called 2P method (photocurable resin method) in which a photocurable resin is spread and the inverted pattern of the stamper is transferred to the transparent substrate 2 is suitable. Further, when the transparent substrate 2 is formed of a thermosetting resin such as an epoxy resin or a photocurable resin, a molten substrate material is injected into a mold by intravenous injection, and a transparent substrate having a preformat pattern is formed. A so-called casting method for molding the second material is suitable.

On the other hand, in the second preformat pattern 31, a read-only signal such as an information signal is preformatted. As shown in FIG. 2, the first and second preformat patterns 3 and 31 are concentric and have the same pitch when viewed from the plane of the information recording medium 1, and are spirally shifted from each other by a half pitch in the radial direction. Alternatively, it is preformatted concentrically. Such first
As shown in FIG. 4, the information recording medium having the second preformat patterns 3 and 31 has a stamper 33 on which an inverted pattern of the second preformat pattern 31 is formed and the first preformat pattern 3 formed. The organic dye material that forms the basis of the organic dye film 32 is spread between the transparent substrate 2 and the cured organic dye material, and the organic dye film 32 is peeled off from the interface with the stamper 33.
The pattern can be formed by transferring the reverse pattern to the organic dye film 32.

The organic dye film 31 is made of, for example, spiropyran dye, fulgide dye, cyanine dye, phthalocyanine dye, polymethine dye, anthraquinone dye,
It has a light reflectance of 60 to 80% and a light absorption of 20 to 40%, such as a xanthene dye, a triphenylmethane dye, a pyrylium dye, an azulene dye, or a metal-containing azo dye. It is composed of an organic dye material that absorbs and converts it into heat and changes optical characteristics such as reflectance. When a spiropyran-based dye or a fulgide-based dye is used, a rewritable optical information recording medium capable of erasing and rewriting information can be manufactured. When a cyanine dye or a phthalocyanine dye is used, a write-once optical information recording medium on which information can be written only once can be manufactured.

The reflection film 4 is formed of, for example, a metal material such as gold or aluminum, an alloy material containing these metal materials as a main component, and a high reflectance material such as a so-called silver mirror. When a metal material is used, the reflective film 4 can be formed by using a vacuum film forming method such as vacuum evaporation or sputtering.

The magnetic recording film 5 is formed by vacuum-forming a ferromagnetic metal material on the reflective film 4 or by applying a magnetic paint obtained by adding a binder, a lubricant and a reinforcing agent to the ferromagnetic metal powder.
It is formed by coating on or bonding a magnetic sheet. The surface of the magnetic recording film 5 is formed smooth to enhance the slidability of the magnetic head. Ferromagnetic metal materials suitable for forming the magnetic recording film 5 by vacuum film formation include:
Co, Fe, Ni, Co-Ni alloy, Co-Cr alloy,
Co-P alloy, Co-Ni-P alloy and the like can be given. Further, ferromagnetic metal materials suitable for constituting the magnetic paint include γ-Fe ₂ O ₃ powder, Fe ₃ O ₄ powder, Co
Γ-Fe ₂ O ₃ powder, Co-containing Fe ₃ O ₄ powder, Fe powder, Co powder, Fe—Ni alloy powder, and the like. As a binder constituting a magnetic paint together with these ferromagnetic metal powders, for example, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, urethane resin, polyisocyanate compound and the like are used. As the lubricant, various organic compounds such as higher fatty acids, higher fatty acid esters, liquid paraffin, squalane, and fluorine can be used. Lubricant addition rate is 5 to 25% by weight based on ferromagnetic metal powder
Is appropriate. As the reinforcing agent, for example, aluminum oxide powder, silicon carbide powder, silicon nitride powder and the like are used. The addition rate of the reinforcing agent is 5 to 2 with respect to the ferromagnetic metal powder.
5% by weight is suitable. When the magnetic recording film 5 is formed by vacuum film formation, it is preferable to apply or impregnate the above-mentioned lubricant on the surface of the magnetic recording film 5 to form a lubricating layer.

Hereinafter, a method for recording and reproducing information using the information recording medium according to the embodiment will be described with reference to FIGS.

FIG. 5 is an explanatory diagram of the drive device.
Is an information recording medium, 11 is a spindle motor that rotationally drives the information recording medium 1, 12 is an optical head that reads information from the first information recording layer, and 13 is a space between the information recording medium 1 and the second information recording layer (magnetic recording film 5). Denotes a magnetic head for recording and reproducing information. The optical head 12 and the magnetic head 13 are attached to the head holding device 14 so as to face each other, and when at least recording, reproducing, and erasing information on the magnetic recording film 5 is performed, the head holding device 14 is driven. By doing so, they are simultaneously transferred by the same amount in the same direction. The optical head 12 is arranged opposite to the transparent substrate 2 of the information recording medium 11 with a predetermined sense between the optical head 12 and the magnetic head 13.
Slides on the magnetic recording film 5 formed on the information recording medium 11.

The spindle motor 11 is provided with time base servo means, and is controlled so that the information recording medium 1 can be driven to rotate at a predetermined rotation speed. The optical head 12 is provided with a tracking servo unit and a focus servo unit. The laser beam 15 emitted from the optical head 12 is always focused on the interface between the preformat pattern 3 of the transparent substrate 2 and the reflection film 4. In this state, the recording track can be followed. The magnetic head 13 is provided with a tracking servo means, and is driven by a tracking servo signal read by the optical head 12.
Since the above-mentioned servo means are technologies belonging to the public domain and have no direct relation to the gist of the present invention,
Description is omitted.

As shown in FIG. 6A, the information recording medium 1 of this embodiment is obtained by focusing a reproduction laser beam spot on an interface between the first preformat pattern 3 and the organic dye film 32. A formatted address signal or a recorded information signal can be read. Further, the recording laser beam spot is focused on the desired address read in this manner, the laser energy is absorbed by the organic dye film 32 and converted into heat, and the heat causes the organic dye film 32 to be localized. The information can be added by discoloring the information. Further, as shown in FIG. 6B, the information signal preformatted on the organic dye film 32 can be read by focusing a laser beam spot on the interface between the second preformat pattern 31 and the reflection film 4. it can. Of course, by driving the magnetic head, information can be recorded on and reproduced from the magnetic recording film 5. Thus, the information recording medium 1 of the present example is
A total of three information recording layers can be formed on one transparent substrate 2.

In the above embodiment, the tracking of the magnetic head 13 was performed by the tracking servo signal obtained from the first information recording layer, but instead of such a configuration, the tracking servo signal was transmitted to the magnetic recording layer 5 itself. Can be written magnetically and the magnetic head 13 can be used for tracking.

In the above embodiment, the reflection film 4 is provided between the organic dye film 31 and the magnetic recording film 5. However, when a magnetic recording film 5 having excellent light reflectivity is used, The reflection layer 4 can be omitted. The magnetic recording film 5 having excellent light reflectivity includes Co, Fe, Ni, C
o-Ni alloy, Co-Cr alloy, Co-P alloy, Pt-
A material obtained by vacuum-forming a ferromagnetic metal material such as a Co alloy or a Co-Ni-P alloy can be used.

[0026]

As described above, according to the present invention,
Since a first information recording layer capable of recording and reproducing information by optical means and a second information recording layer capable of recording and reproducing information by magnetic means are laminated on a transparent substrate, one transparent substrate Two information recording layers can be formed thereon, and the recording capacity of the information recording medium can be increased.

Further, since the second information recording layer having excellent chemical stability is formed outside the first information recording layer having low chemical stability when viewed from the transparent substrate side, the protective layer is omitted. Thus, an information recording medium which is inexpensive and has excellent long-term storage characteristics can be provided.

Further, at the interface between the transparent substrate and the first information recording layer, a first preformat pattern from which a signal can be read by optical means is provided, and the first information recording layer and the second information recording layer are provided. Since a second preformat pattern from which a signal can be read by optical means is provided also at the interface with the layer, and the first and second preformat patterns are arranged so as to be shifted from each other in the plane direction of the transparent substrate. Reading a signal from the first preformat pattern by optical means, reading a signal from the second preformat pattern by optical means, and writing information to the first information recording layer by optical means; The information can be recorded on and reproduced from the second information recording layer by means of time.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an information recording medium according to an embodiment.

FIG. 2 is a plan view of the information recording medium according to the embodiment.

FIG. 3 is a partially enlarged plan view of the information recording medium according to the embodiment.

FIG. 4 is an explanatory diagram of a manufacturing process of the information recording medium according to the embodiment.

FIG. 5 is an explanatory diagram of a drive device.

FIG. 6 is an explanatory diagram illustrating a recording / reproducing method for an information recording medium according to an example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 information recording medium 2 transparent substrate 3 first preformat pattern 4 reflective film 5 magnetic recording film 31 second preformat pattern 32 organic dye film

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-179951 (JP, A) JP-A-56-140536 (JP, A) JP-A-3-75190 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) G11B 13/04 G11B 7/24

Claims (1)

(57) [Claims] A transparent substrate, a first information recording layer on which information can be recorded and reproduced by optical means, and a second information recording layer on which information can be recorded and reproduced by magnetic means, At the interface between the transparent substrate and the first information recording layer, a first preformat pattern from which signals can be read by optical means is provided, and the first information recording layer and the second information recording layer are A second preformat pattern from which signals can be read out by optical means is also provided at the interface of
And an information recording medium, wherein the second preformat patterns are arranged so as to be shifted from each other in the plane direction of the transparent substrate.