JPS61194652A - Optical information recording tape - Google Patents

Abstract

PURPOSE:To obtain an information recording tape which permits rewriting by using a metal or alloy having at least two kinds of phases in a solid phase state and utilizing the change of the crystal structure arising from the transformation of said phases. CONSTITUTION:The recording medium consists of the metal or alloy which has at lest two kinds of the crystal structure in the solid state, maintains the crystal structure of one temp. region in the other temp. region and/or induces the volumetric changes different from each other in the crystal state. For example, a large difference in the spectral reflectivity of a reddish copper color and golden color is observed at about 500nm when the tape-shaped recording medium deposited by evaporation with a 14wt% Al-4wt% Ni-Cu alloy is subjected to heating and quick cooling and to heating and slow cooling. The information processing is therefore possible at this wavelength. The recording, reproduction and erasure of information are executed by the laser spot stopped down to 1.0 micron to several microns by an objective lens. The difference between recording and erasure is obtd. by varying the intensity of laser power.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a novel information recording medium, and particularly to a method for changing the crystal structure of the recording medium by photothermal energy.

The present invention relates to an information recording medium on which information can be recorded, reproduced, and erased.

[Background of the invention]

In recent years, as information recording becomes more dense and digital, various information recording and reproducing methods are being developed. In particular, optical discs that use laser energy to record, erase, and reproduce information are capable of higher recording densities than magnetic discs, as stated in Industrial Rare Metal & 80.1983 (Optical Disks and Materials), and future information This is a powerful method of recording. Among these, laser playback devices have been put into practical use as compact discs (CDs).

On the other hand, recordable methods can be broadly divided into two types: write-once type and rewritable type. The former allows writing only once and cannot be erased, while the latter allows repeated recording and erasing. In the write-once type recording method, a laser beam is used to destroy or shape the recording portion of the medium to create unevenness, and for reproduction, a change in the amount of light reflected due to the interference of the laser beam at the uneven portion is used for reproduction. For this recording medium, it is generally known to use To or an alloy thereof, and to form irregularities by melting and sublimating the To. This type of medium has problems such as toxicity. Magneto-optical materials are the mainstream for rewritable recording media. This method uses optical energy to invert and record the local magnetic anisotropy of the medium near a carry point or compensation point temperature, and the polarization plane of the polarized incident light at that part is caused by the magnetic Faraday effect and magnetic Kerr effect. Play with the amount of rotation. This method is considered to be the most promising rewritable method, and active research and development is underway with the aim of putting it into practical use in the next few years. However, there is currently no material with a large amount of rotation of the plane of polarization, and even with various measures such as multilayer film formation, there is a big problem that output levels such as S/N and C/N are low. Other rewritable systems utilize reflectance changes due to reversible phase changes between amorphous and crystalline recording media. Furthermore, write-once types that utilize a unidirectional phase change between crystalline and amorphous are also known. However, in this method, the crystallized portion of the amorphous phase is low;
The instability of the phase at room temperature is a major problem that affects the reliability of the disk.

[Purpose of the invention]

An object of the present invention is to provide a rewritable optical information recording tape.

[Summary of the invention]

The present invention is characterized by comprising a recording medium using an alloy of gold, which 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. It is a tape-shaped information recording and reproducing medium. That is, the metal or alloy according to the present invention has at least 2
It has various phases, and can record, erase, and reproduce information such as signals, 2 characters, 9 figures, and symbols by utilizing changes in the crystal structure accompanying the transformation of these phases.

The recording medium is a metal or alloy that has at least two types of crystal structures in a solid state, maintains the crystal structure in one temperature range in the other temperature range, and/or causes different volume changes in the crystal state. It is characterized by consisting of.

Note that any alloy that causes a change in unevenness can be used even if no crystal change occurs.

Examples of alloys include Cu-AQ alloy, Cu-Zn alloy, Cu-AM-Zn alloy, Cu-An-Ni alloy, Cu
-An-Mn alloy, Cu Al2 Fe-Cr alloy, Cu-Ga alloy, Cu AQ Ga alloy, Cu-
In alloy, Cu-AM-In alloy.

Cu-Ga alloy, Cu-AQ-Ga alloy, Cu-
8n alloy, Cu-Ta alloy, Cu-Ti alloy.

Cu-Al-8n alloy, Cu-Zn alloy, Cu-8i alloy, Cu-8b alloy, Cu-Ba alloy.

Cu-Ba alloy, Cu-Mn alloy, Cu-Pd alloy, C
u-Pt alloy, Ag-Zn alloy eAg-Au alloy, Ag
-Cd alloy, Ag-In alloy.

A g-Ga alloy, A g-A n -A u alloy *Ag-A fl -Cu alloy, Ag-AQ-Au-
Cu alloy.

Ag-Al-Cd metal alloy vAg-Pt metal alloy + Ag-8 alloy, Ag-8n alloy, Ag-To alloy tAg-Ti alloy,
Ag-Zr alloy, Ag-As alloy.

Ag-Au alloy, Ag-Ba alloy, Ag-Mg alloy, A
g-Li alloy, Ag-Mn alloy, AQ-Fe alloy, AQ
-Mg alloy, Al1-Mn alloy.

AM-Pd alloy, AQ-Ta alloy, An
-Ti alloy, AQ-2n alloy, An-Zr alloy, Ni
-5b alloy, Ni-8i alloy, Ni-8n alloy.

Ni-Ga alloy, Mn-Ga alloy, N1-Ga alloy, N
i-Mn alloy, Ni-8 alloy, Ni-Ti alloy, Fa-
As alloy p As S alloy, As-Zn alloy, Fe
-Ba alloy, Fe-Ni alloy.

Fe-Cr alloy, Fe-P alloy, Mn-Pd alloy.

Alloy Mn-P, Mn-Sb alloy, Mn-8i alloy, Au-Ca alloy y A u A Q alloy HA u
-In alloy, Au-Ga gold alloy Au-Cd alloy.

Au-Cu alloy, Au-Fe alloy, Au-Mn alloy, Au-Zn alloy, Ba-Ca alloy, Bi-pb gold alloy Bi-TQ alloy, Ti-Ni alloy.

Ni-V alloy, Ni-Zn alloy, Cd-Li alloy.

Cd-Mg alloy, Cd-Pb alloy, Cd-Sb alloy, 5
b-In alloy, 5b-In-Ss alloy.

M g -Ce alloy, Co-Cr alloy, Co-Ge alloy, Go-Mn alloy, Go-Sb alloy, Go-V alloy, I
n-Mg alloy, In-Mn alloy, In-Ni alloy, In
-8n alloy, In-Tri alloy.

Li-Zn alloy, Mn-Zn alloy, Pb-TQ alloy, p
b-s alloy, pb-sb gold alloy Pd-Zn alloy, 5n-
Sb alloy, TA-8b alloy, 5b-Zn alloy, Ti-8
n alloy, Tfi-8n alloy.

Zr-8n alloy, Zr-Th alloy, Ti-Zn alloy, T
Examples include i-Zr alloy.

As examples of alloys, the following are preferred in terms of weight composition.

Ag with 30-46% Zn, 6-10% AQ, 40-60
%Cd, 20-30% In, 13-23% Ga alone,
Cu with 10-20% AM, 20-30% Ga, 20-4
0% In, 20-30% Ge, 15-35% Sn, 10
~60%Zn, 5~10%Si, 4~15%Be, 30
~45% sb alone, 15~25% In on Au, 10~
15% Ga, 5-25% Zn, 20-55% Cod.

2.5-5% AQ alone, 55-60% AQ on Ni, 4
Alloys containing 0-50% Ti alone, In-25-35
%TQ alloy, alloy with 55% or less of pt added to Fa, M
n-5~50% Cu alloy, 5e15~25%-In
30-40%-sb gold alloys
Ingredients, 4th ingredient.

The following elements other than the second component can be added as the fifth component and the like.

Ia, l1ae IVa, Va, VIa, ■a, ■.

rb-vb, the total of one or more rare earth elements is 1
It is 5% by weight or less.

Specifically, the Ia group is Li, and the IIa group is Mg.

The Ca and IVa groups are Ti, Zr, and Hf, and the Fa group is V.

Nb, Ta, ■a group are Cre M o * W, ■a
The group is M n , and the group (■) is Co, Rh, Ir, Fa, and Ru.

OR, Ni, Pdt Pt, Ib group is Cu * A g
eA u, ■b group is Zn, Cd, mb group is B, AQ
.

Ga, In, group IVb are C, Si, Go, and Sn.

The pb and vb groups are P, Sb, and Bi, and the rare earth elements are Y.

La, Ce, Sm, Gd, Tb, Dy, and Lu are preferred, particularly preferably 0.1 to 5% by weight, and Ta,
It is also possible to use an alloy in which irregularities are formed by melting and sublimating an alloy mainly containing Ss.

[Embodiments of the invention]

FIG. 1 shows this information recording medium made into a thin tape-like flexible plastic material.

In the figure, 3 indicates a plastic base, and 2 indicates an information recording medium. If this is used in the same way as the currently widely used magnetic recording tape, a large-capacity storage device greater than that of an optical disk device will be possible.

In Fig. 2, AQ 14% by weight-Ni4 is used as a recording medium.
Il@ indicates the spectral reflectance when the tape-shaped information recording medium on which the weight%-Cu alloy was vapor-deposited was heated and rapidly cooled, and when it was heated and slowly cooled. The appearance is red when heated and rapidly cooled, and golden yellow when removed by heating.

As shown in the figure, the spectral reflectance of red body color and golden color is 500n.
A large difference can be seen near m. The spectral reflectance at this wavelength is 8.5% for the red body color and 23.9% for the golden color, and the spectral reflectance of the latter is approximately three times that of the former. Therefore, it was found that information processing is possible at this wavelength.

FIG. 3 is an explanatory diagram of the principle of recording, reproducing, and erasing information on the tape-shaped information recording medium according to the present invention.

Recording, reproducing, and erasing of information is done with an objective lens of 1.0
It is performed using a laser spot narrowed down to a few microns. The difference between recording and erasing is determined by changing the strength of the laser power, and information is reproduced by reading the reflection from the tape with an optical sensor.

The laser beam 15 is directed to the roller 13 by the objective lens 14.
Forming a subot on the tape-shaped information recording medium 1 on top,
The recording of information in the tape traveling direction, which is performed by heating and recording information, is performed by roller 13. By moving the reels 11 and 12, recording in the width direction of the tape is performed using a laser beam 15.
This is achieved by swinging in the direction of arrow 16.

However, at this time, the problems are the focus position shift due to scanning of the laser beam in the tape width direction and the problem of reflected light. This situation is shown in FIG. 4. FIG. 4(a) shows a cross section 102 of the tape cut in the width direction and the objective lens 10. In this case, when the laser beam L1o1 is incident perpendicular to the tape, it is focused on the tape, but when the laser is scanned (L102), it is not focused on the tape surface, and the reflected light does not return to the objective lens. diverges in a different direction (L
103) Information cannot be reproduced in this case.As a countermeasure, the tape is made into an arc shape (103) as shown in FIG. 4(b).

If you irradiate this with a laser beam, the focus will always be on the tape, and the returned light will not diverge.

It was confirmed that the recorded portion was concave or convex with respect to the base surface.

FIG. 5 shows a specific configuration of the head. The tape-shaped recording medium is pressed from above and below by heads 16 and 61 in order to maintain the above-mentioned arcuate shape. These heads are optically transparent and pass the focused laser light indicated by the LSI to form a beam spot on the tape. Also, at this time, the beam spot is scanned in the direction shown by arrow 43.

FIG. 6 shows the configuration of an information recording/reproducing/erasing apparatus for a tape-shaped recording medium. First, information recording and reproduction will be explained. L2
The laser beam indicated by 1 is transmitted through a polarizing beam splitter 11,
It is made of one λ/4 plate and is focused by an objective lens 13.

Thereafter, it is reflected by the galvanometer mirror 14 and focused onto the recording medium 1.

Therefore, the spot temperature of the recording medium increases, making recording or erasing possible. The difference between recording and erasing is the difference in laser beam intensity. Reproduction of information.

In addition to the methods described so far, this can be realized by picking up the reflected light from the recording medium with a photodetector 20.

Recording of information in the tape width direction is performed by rotating 14 galvano mirrors. At this time, the centers of the arc of the head shown by centers 17 and 16 of the galvano mirrors 14 are set to be the same.
Moreover, if the focal position of the objective lens 13 is configured to overlap on a circular arc, the focal point will always be focused on the recording medium as shown by L14a and L14b in the figure. Therefore, this optical system does not require a focusing system as long as the tape and head are always used in close contact with each other.

An Ag-40% by weight Zn alloy film was formed by sputtering in the same manner as described above. In order to prevent the alloy film from being oxidized by heating during recording and erasing, and to prevent it from peeling off from the substrate, a protective film (thickness: 30 nm) of SiO was formed on the surface by vapor deposition. A DC-magnetron sputtering method was used to deposit the alloy film on the glass plate, and an RF sputtering method was used to form the Sin film. The sputtering output was set to 140 to 200 W, and the substrate temperature was set to 200°C. After evacuating the inside of the container to about 10'' Torr, Ar gas was introduced at 5 to 30 m Torr to produce a thin film. The film thickness was set to be about 30 nm for the sinusoidal film, and the thickness of the alloy film was varied within the range of 0.05 to 10 μm. Using the optical disc produced in this way, recording, erasing, and repeating such a process were performed.
The Ar gas laser was continuously oscillated. The sample was placed on a manual movement stage, the sample was moved, and the 200 mW laser beam was focused and scanned on the film surface of the sample. The 0 alloy film, which turned pink in the areas irradiated with laser light, had previously been heat-treated along with the substrate to become silvery white.

Next, the focus of the laser beam was slightly shifted from the film surface, the output density of the laser was lowered, and the laser beam was scanned in a direction intersecting the pink area (up and down in the figure). As a result, the original pink color was erased and the color changed to silvery white.

It was confirmed that concave or convex portions were formed on the base surface at the same time as these color changes were recorded, and that the original flat surface was restored by erasing.

From the above results, it was confirmed that recording and erasing can be performed using the alloy in a thin film state. It has been confirmed that this writing and erasing can be repeated any number of times.

〔Effect of the invention〕

As described above, recording and reproduction can be performed using the present invention.

A large-capacity optical information recording device that can be erased can be realized.

Optical information tape is a promising ultra-high capacity recording method for supplementary storage of information.

[Brief explanation of drawings]

Figure 1 is an outline of an optical information recording tape, Figure 2 is the spectral characteristics of the tape, Figure 3 is a diagram of the principle of a recording/reproducing/erasing device for optical information recording tape, and Figure 4 is the principle of optical scanning in the tape width direction. figure,
FIG. 5 is a schematic diagram of the optical head, and FIG. 6 is an explanatory diagram of optical recording, reproduction, and erasing using a galvano mirror. DESCRIPTION OF SYMBOLS 1... Optical information recording tape, 10... Laser beam, 11... Polarizing beam splitter, 12... λ/4
Board. 13... Objective lens, 14... Galvano mirror 11
6... Arc-shaped head, 20... Optical sensor. Thatch 1 Enclosure 2 Hard growth (FI party) 4th - Hard growth ((L)

Claims (1)

[Scope of Claims] 1. In a device having a recording medium on a flexible substrate, the recording medium has at least two types of crystal structures in a solid state, and the crystal structure in one temperature range is different from that in the other temperature range. 1. An optical information recording tape characterized by being made of a metal or an alloy that is held in a crystalline state and/or exhibits different volume changes in a crystalline state. 2. The optical information recording tape according to claim 1, wherein the recording medium is made of a metal or alloy whose crystal structure at high temperatures in a solid state is maintained by supercooling from high temperatures. 3. The recording medium is made of a metal or alloy in a crystalline state that undergoes phase transformation, and has phases with different crystal structures in at least two temperature ranges in a solid state, and there are recesses caused by the transformation between the phases. Or, by forming a convex part to change the state of light reflection with the base surface, it can be used as information such as signals, characters, figures, etc.
2. The optical information recording tape according to claim 1, further comprising a heating means for memorizing a symbol so that it can be identified or erasing the concave or convex portion to its original state, and a means for reproducing the information. 4. The recording medium contains elements from groups I, b to VII, of the periodic table.
Claims 1 to 3 consist of a metal or alloy whose main component is a transition metal element of Group B or Group VIII metal element.
The optical information recording tape according to any one of paragraphs.