JPS61133035A - Information recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical disk which can be selectively used for permanent recording and rewritable recording by using a recording and reproducing medium made of a metal or alloy which has at least two kinds of crystal structure in s solid state and maintains the crystal structure in one temp. region in the other temp. region. CONSTITUTION:An inter-crystal transition alloy has the crystal structure which is different in high and low temp. states. The quickly cooled crystal structure is formed by the quick cooling from the high temp. Such inter-crystal transition alloy consists preferably of an alloy composed of at least one kind of the group Ib elements of periodic table and at least one kind selected from the group IIb and Vb elements. Recording pits 6 on a disk 1 are divided to the pits for executing permanent recording and the pits for executing rewritable recording. The recording and the pits for executing rewritable recording. The recording pit 6A is the part of a recording alloy layer 9 where the reflectivity changes and the rewritable recording is executed in said part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an information recording device capable of permanently recording information and erasable information recording on a single optical disc.

In recent years, in order to meet the demand for high-density recording of information, optical disk devices that focus laser light into a narrow beam and use the concentrated heat to record and reproduce information have attracted attention.

It is desirable for a disc for an electronic file to have (1) a rewritable area for recording information, and (2) a permanent recording area such as an index, address area, and important information recording area.

A familiar usage example of an optical disk device having two different recording areas is a karaoke device using an optical disk.
GM), sing along to this song, store this audio in the rewritable area, and reproduce the signals from the two areas at the same time. Of course, it can also be used for 0AIlli, so-called ROM of storage devices of various computers, etc.

It can also be used as an alternative to RAM.

However, conventionally known discs can only carry either permanent recording or rewritable recording. As a result, various inconveniences have arisen, such as important information being erased by mistake, or conversely, as it is impossible to rewrite information, a new area on the disk is required each time information is rewritten. Ta.

There are also discs that have both an optical disc area and a magneto-optical disc area, thereby making surface recording possible. However, since these image recording information detection methods are different, the mechanism of the entire apparatus becomes complicated, and the manufacturing method of the disk itself also becomes complicated.

Additionally, phase changes on the disk (e.g. changes in optical reflectance)
Although recording and reproducing devices using 3D have the advantage of being rewritable, there are still some instability factors, such as the possibility of a reverse phase change occurring due to sudden changes in the environment or changes over time. are doing.

As a solution to this problem, Japanese Patent Application Laid-Open No. 59-1406
No. 38 "Information Recording Method" is known. Simply put, this is an information recording method in which information is recorded and reproduced by irradiating a recording medium with a light beam, and the recording surface of the recording medium is irradiated with a light beam to change its shape, thereby making the information permanent. No record.

Further, the recording surface of the recording medium is irradiated with a light beam to change the reflectance, thereby recording erasable information. However, the reality is that a stable recording medium that satisfies these requirements has not yet been developed.

One example of a recording medium currently being widely developed as a recording medium for optical disks is one that uses Te, a material that undergoes a phase change between crystalline and amorphous upon irradiation with light, but these materials have no toxicity. Since it has an adverse effect on the human body, care must be taken when using it during the manufacturing stage, and the board structure is complicated due to its inclusion.

[Purpose of the invention]

In view of the above, the present invention aims to construct a permanent recording area and a rewritable area using the novel non-toxic metal material of the present invention.

[Summary of the invention]

The recording material of the present invention uses a recording/reproducing medium using a metal or alloy that has at least two types of crystal structures in a solid state and maintains the crystal structure in one temperature range in the other temperature range. By irradiating the recording surface of this material with a light beam and changing its shape, information is permanently recorded.
Also, erasable information is recorded by irradiating the recording surface of the recording medium with a light beam to change the reflectance.

[Embodiments of the invention]

First, what kind of new recording medium is it? The alloy composition, non-bulk, and its manufacturing method.

Explain the characteristics and uses.

(Alloy Composition) The intercrystalline transition alloy of the present invention has different crystal structures at high and low temperatures, and the rapidly cooled crystal structure is formed by rapid cooling from a high temperature.

Furthermore, the phase formed by this rapid cooling changes into a crystalline structure at a low temperature by heating at a predetermined temperature. In order to obtain a crystal structure different from the crystal structure at a low temperature by rapid cooling from a high temperature, such a change in crystal structure occurs at a cooling rate of 102°C/second or more or 101°C/second or more. preferable.

The intercrystalline dislocation alloy of the present invention is preferably an alloy of at least one element of group Ib of the periodic table and at least one element selected from group Nb, group IIb, group IVb, and group Vb. Among these alloys, copper is the main component, An
, Ga, In, Ge, and Sn are preferable, and alloys containing Ni, Mn, Fe, and Cr as a third element in these alloys are further preferable.

Further, alloys containing silver as a main component and containing AQ, Cd, and Zn are preferable, and Cu, Cu, and Zn are further added to these alloys as a third element.
Al2. An alloy containing Au is preferred.

An alloy containing gold as a main component and containing Al is preferable.

The alloy of the present invention includes the above-mentioned group Ib elements, group nb, and group (ii) b.

Those having intermetallic compounds with group IVb and group Vb elements are preferred.

(Non-bulk and manufacturing method thereof) In order to obtain reflectance variability, the crystal mass transition alloy of the present invention must be able to form a supercooled phase by heating and rapidly cooling the material. In order to create and store information at high speed, it is desirable to use a non-bulk material with a high rapid heating and cooling effect and a small heat capacity. That is, it is desirable to be a non-bulk material having a volume that allows substantially only a desired area portion to be changed to a crystal structure different from a reference crystal structure throughout the depth by energy input to a desired minute area. Therefore, in order to fabricate high-density information in a desired small area, a non-bulk foil with a small heat capacity is required.

Films, thin wires, powders, etc. are desirable. As recording density,
For producing information in a minute area such as 20 megabits/d or more, the film thickness is preferably 0.01 to 0.2 μm. In general, intermetallic compounds are difficult to plastically work6. Therefore, it is effective to directly rapidly cool and solidify the material from the gas or liquid phase to form it into a predetermined shape in order to make it into foil, film, thin wire, or powder. These methods include the PVD method (vapor deposition, sputtering method, etc.), the CVD method, and the quenching method in which molten metal is poured onto the circumferential surface of a metal roll and rapidly solidified. , electroplating, chemical plating, etc. When using a film or powder material, it is effective to form it directly on the substrate or to apply it and adhere it to the substrate. When coating, it is best to use a binder that does not cause a reaction even when the powder is heated, and also to prevent the material from oxidizing due to heating.

It is also effective to coat the surface of a film or coating layer formed on the substrate.

The foil or thin wire is preferably formed by a molten metal quenching method, and preferably has a thickness or diameter of 0.1 m or less.

In particular, in order to produce foil or thin wire with a crystal grain size of 0.01 μm or less, a thickness or diameter of 0.05 m or less is preferable.

The powder is preferably formed by an atomization method in which molten metal is jetted together with a gaseous or liquid refrigerant and then poured into water to be rapidly cooled. The particle size is preferably 0.1 m or less, and ultrafine powder with a particle size of 1 μm or less is particularly preferable.

The film can be formed by vapor deposition, sputtering, CVD electroplating, chemical plating, etc., as described above.

In particular, sputtering is preferable to form a film with a thickness of 0.1 μm or less, and sputtering allows easy control of the target alloy composition.

(ffllllt) The crystal mass transition alloy of the present invention has different crystal structures at high and low temperatures, and must have a composition of an undercooled phase in which the crystal structure at high temperature is maintained at low temperature by rapid cooling from high temperature. . Although it has an irregular lattice crystal structure at high temperatures, the supercooled phase is preferably an intermetallic compound having a Cs-CQ type or Do3 type ordered lattice, for example. As the alloy of the present invention is capable of greatly changing optical properties, it is preferable that the alloy mainly forms this intermetallic compound, and a composition in which the entire alloy forms an intermetallic compound is particularly preferable. This intermetallic compound is called an electronic compound,
In particular, alloy compositions near 3/2 electron compounds (average outer shell electron concentration e/a of 3/2) are good.

Further, the crystal mass transition alloy of the present invention preferably has an alloy composition having in-phase transformation, for example, eutectoid transformation or enveloping transformation, and the alloy can be obtained with a large difference in spectral reflectance by quenching from high temperature and non-quenching. .

The alloy of the present invention preferably has ultrafine crystal grains, and the grain size is particularly preferably 0.1 μm or less.

That is, the crystal grains are preferably smaller than the wavelength of visible light, but may be smaller than the wavelength of semiconductor laser light. - (Characteristics) The recording material of the present invention can form at least two types of spectral reflectance in the visible light region at the same temperature.

That is, it is necessary that the spectral reflectance of a material having a crystal structure (tissue) formed by rapid cooling from a high temperature is different from the spectral reflectance of a material having a crystal structure (set I1a) formed by non-quenching.

Further, the difference in spectral reflectance obtained by quenching and non-quenching is preferably 5% or more, particularly preferably 10% or more. If the difference in spectral reflectance is large, it is easy to visually identify the color, and this has a significant effect in various uses described later.

As a light source for spectrally reflecting, electromagnetic waves other than visible light can be used, and infrared rays, ultraviolet rays, etc. can also be used.

Other properties of the crystal mass transition alloy of the present invention include electrical resistivity, optical refractive index, optical polarization rate, and optical transmittance, which can be changed reversibly in the same way as spectral reflectance, and various information can be obtained. It can be used to record and reproduce recorded information.

Since the spectral reflectance is related to the surface roughness of the alloy, it is preferable that at least the intended portion has a mirror surface so as to have 10% or more in the visible light region as described above.

(Applications) The crystal mass transition alloy of the present invention can be used to improve physical or electrical properties such as spectral reflectance of electromagnetic waves, electrical resistivity, refractive index, polarization index, transmittance, etc. due to partial or total change in crystal structure by heating and quenching. It can be used as an information recording element by changing the characteristics and utilizing the changes in these characteristics.

As a means of recording information, electrical energy in the form of voltage and current, electromagnetic waves (visible light, radiant heat, infrared, ultraviolet,
(e.g., light from a flash lamp, electron beam, proton beam, argon laser, laser beam from a semiconductor laser, high-voltage spark discharge, etc.) can be used, and in particular, the change in spectral reflectance caused by the irradiation can be used to detect optical discs. It is preferable to use it as a recording medium. Optical disks include digital audio disks (DAD or compact disks), video disks, memory disks, etc. By using the alloy of the present invention in the recording medium of optical disks, playback-only and additional recording types can be created. , can be used in rewritable disk devices, and is particularly effective in rewritable disk devices. The recording method may be either a method of applying energy intermittently in pulses or a method of applying energy continuously. In the former case, it can be recorded as a digital signal.

The present inventors conducted various experiments on the crystal mass transition alloy of the present invention, and investigated how the light reflectance changes before and after recording, with the intention of using it in an optical disk device. I looked into it. The detailed explanation of how the crystal mass transition alloy is created is omitted, and a typical example thereof is shown in Figure 7. In this figure, a represents the state before recording, and b represents the state after recording. . Optical disk devices utilize this characteristic as a rewritable area; for example, 780 (n
The presence or absence of information is determined using a light beam with a wavelength of be.

As is clear from this figure, when recording, the reflectance increases as shown in C, and when erasing, the reflectance decreases as shown in d. Furthermore, when 550 (nm) is selected, the reflectance becomes small during recording as shown in C'.

When erasing, the reflectance increases as shown by d'.

FIG. 1 is an overall view showing an embodiment of an optical disk device to which the present invention is applied. Here, 1 is an optical disk made of the metal mentioned above, 2 is a recording head that writes various data on the optical disk 1, 3 is a playback head that reads data recorded on the optical disk 1, 4 is a recording beam, and 5 is a playback head. Reference beam 6 indicates a recording pit on the disc 1. However, as will be described later, the recording pit is divided into pits for permanent recording and pits for rewritable recording.

FIG. 2 is a cross-sectional view showing the state after rewritable recording has been performed on the optical disc 1 shown in FIG. here,
4A is a low-power recording beam, 7 is an antireflection layer provided on the top of the disk 1, 8 is a protective layer, 9 is the above-mentioned recording alloy that functions as a recording layer, and 10 is a glass substrate. Further, 6A indicates a portion of the recording alloy layer 9 where the reflectance has changed, and this becomes the rewritable recording described above.

As described above, the reflectance of the recording alloy changes depending on how it is heated and cooled. Therefore, by irradiating the disk 1 with the low-power recording beam 4A, the reflectance of the irradiated portion of the recording alloy layer 9 changes. in this way,
Thus, rewritable recording can be performed on the disc 1.

Further, the above-mentioned recording alloy may be in the form of a thin film, and when it is irradiated with a high-output laser power, a hole is formed in the irradiated area. Therefore, it becomes possible to form a pit row by irradiating the optical disc 1 with a high-power beam. .

FIG. 3 is a sectional view showing the state after permanent recording has been performed on the optical disc 1. Here, 4B indicates a high-output recording beam, and 6B indicates a pit hole formed by the recording beam 4B.

When reading pit information recorded on the optical disc 1, a laser output is irradiated onto the disc and its signal is read.

Permanently recorded information is obtained because no reflected light is obtained from the portion where the holes are formed, and rewritable information is obtained due to the difference in the reflectance of the reflected light.

4 to 6 are schematic diagrams showing examples of selective use of permanent recording and rewritable recording according to this embodiment. Here, 4C indicates a beam spot for recording. The details of each of these sessions are as follows.

FIG. 4 is a diagram showing an example in which rewritable recording by the reflectance changing portion 6A and permanent recording by the pit hole 6B are distinguished and used depending on the circumstances.

FIG. 5 is a diagram showing an example in which a guide track is formed by a reflectance changing portion and information is recorded by pit holes.

FIG. 6 is a diagram showing an example in which address signals in the address area 11 are permanently recorded through pit holes 6B, and information is recorded in a rewritable manner.

〔Effect of the invention〕

As explained above, according to the present invention, an optical disc having a simple configuration and a recording/reproducing device therefor can be used to
It is extremely suitable for obtaining a versatile optical disk device, which can be used as a permanent record or a rewritable record.

[Brief explanation of the drawing]

1cjA is an overall view showing an embodiment of an optical disk device to which the present invention is applied, FIG. 2 is a sectional view showing the state after rewritable recording is performed on the optical disk shown in FIG. 1, and FIG. 1 is a sectional view showing the state after permanent recording is performed on the optical disk shown in FIG. 1, and FIGS. 4 to 6 are schematic diagrams showing examples of how permanent recording and rewritable recording are used according to this embodiment. , FIG. 7 shows the wavelength-reflectance characteristics of the recording alloy. DESCRIPTION OF SYMBOLS 1... Optical disk, 2... Recording head, 3... Reproducing head, 4, 4A, 4B, 4C... Recording beam,
5... Reproduction beam, 6, 6A, 6B... Recording pit, 7... Anti-reflection layer, 8... Protective layer, 9... Recording layer (oxidized tape also has 2 figures and 1 hammer rate 3) figure-motion

Claims (1)

[Claims] 1. In an information recording device that records and reproduces information by irradiating a recording medium with a light beam, the light beam is irradiated onto a recording layer of the recording medium to change its shape, thereby permanently recording information. None, and the recording layer of the recording medium is irradiated with the light beam to change the reflectance to record erasable information, and the recording medium has at least two types of crystal structures in a fixed state. An information recording device characterized in that it is made of a metal or an alloy that maintains a crystal structure in one temperature range in another temperature range.