JPS62192944A - Optical recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical recording medium which is extremely less deteriorated in characteristics by temp., humidity or age by disposing an aluminum nitride layer contg. metallic oxides and impurities on a light transmittable base. CONSTITUTION:The metallic oxides to be incorporated into the aluminum nitride layer may be any compsns. as far as the content thereof is in a 0.1-50wt% range. The content preferable in terms of the content of free oxygen and the density of the layer is <=20wt%. <=1wt% Is preferable in terms of adhesive power and the density of the layer and 15wt% is preferable in terms of the stability of the layer and the ease of film formation. the metallic oxides to be incorporated into the aluminum nitride layer are satisfactory if the oxides are of 1 or >=2 kinds of metals selected from Be, Mg, Ca, Sr, Ba, etc. The oxide of 1 or >=2 kinds of the metals selected from Mg, Ca, Al, Ga, In, Si, Sn, Zn, Ti, Cr, Mn, Y, Zr, and light rare earth are more preferable in terms of the light transparency, cost and nontoxicity of the layer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical recording medium that performs recording, reproduction, or erasing using light.

[Prior art]

In conventional optical recording media, the recording layer used for recording, reading, and erasing using light is oxidized and corroded by moisture, oxygen, or heat in the air, resulting in storage.

The characteristics of recording 1- (0/N, pit error rate, reflectance, refractive index, θ, Ha, etc.) deteriorate during transportation or use, and pinholes occur frequently, making it unusable. It had the disadvantage of disappearing. Therefore, Japanese Patent Application Laid-Open No. 59-110052.

As disclosed in Japanese Unexamined Patent Publication No. 60-151659, aluminum nitride, silicon nitride, MgF, .
Non-oxides such as Zn8, OeF, AjF, -5NaF and 5in2. SiO, u, o, , ZrO,, Ti
Sputtering, vapor deposition, ion-blating CV D (Chemical Vap
The film was formed and used by a vacuum film forming method such as (or Denontion).

[Problems to be solved by the invention] However, in the above-mentioned prior art, sputtering, vapor deposition,
Ion brating, OV D (Chemica)
.

Nitrides such as silicon nitride and aluminum nitride formed by vacuum deposition methods such as Vapor Deposition method have a low coefficient of thermal expansion, and are suitable for use on polymer substrates (acrylic resin,
When formed into a film on epoxy resin, polycarbonate resin, etc.), cracks are likely to occur and the filling rate is low, resulting in poor drinking retention properties. Similarly, oxides and sulfides such as acid oxides, silicon dioxide, and lead sulfide have poor protective properties due to their low filling rates, and at the same time, they contain a large amount of free oxygen, which may oxidize the recording layer. In addition, the problem of not completely absorbing moisture and oxygen in the air (which causes changes in optical properties)
Was.

Therefore, the present invention aims to solve all of these problems, and its focus is on sputtering.

Vapor deposition, ion brating, OVD (Chemical
Even when the film is formed using a vacuum film-forming method such as the alVapor Deposition method, it has a high filling rate, has good adhesion, and has little change in temperature, humidity, or over time in the 5 optical conditions.
By using a film that does not have any problem with thermal expansion coefficient and does not easily cause cracks, the temperature of the parameters necessary for recording, reproducing or erasing, such as dC recording I-〇〇/N, pit error rate, transmittance, θ, and He, can be maintained. It is an object of the present invention to provide an optical recording medium that undergoes extremely little change due to humidity or aging.

[Means for solving problems]

An optical recording medium that performs recording, reproduction, and erasing using light is characterized by disposing an aluminum nitride layer containing metal oxide and impurities on a transparent support.

In the present invention, the metal oxide contained in aluminum nitride may have any composition as long as it is in the range of 0.1 to 50 percent, but depending on the content of free oxygen and the density of the layer, It is desirable that the amount is less than %. It was a cabinet.

From the viewpoint of adhesion and 1-weight density, it is desirable to have 1 weight M° percent or more. Further, from the viewpoint of layer stability and IQL ease of manufacture, 2 to 15 weight percent is desirable.

Further, in the present invention, the gold-14 oxides contained in the aluminum nitride layer are Be, Mg, Ca, Sr, and Ba.

B, u, Ga, n, lEi, Sn, Pb, As, Sb
, se, Tθ.

Zn, Cd, Ti, V, Or, Mn, Fe, Zr, Nb
, Mo.

La, Co, Pr, Nd, Pm, Sm, En, Gd, T
b.Dy.

Any oxide of one or more metals selected from Ho, Er, Hf, Ta, W, Re, and O8 may be used, but from the viewpoint of transparency of one layer, cost, and harmlessness, Mg* C
a*Al IGa, In, Si, Sn, Zn, Ti, O
r.

Oxides of one or more metals selected from Mn, Y, Zr, and rare earth metals are desirable.

〔Example〕

1 to 6 show the basic cross-sectional configuration of an optical recording medium in an embodiment of the present invention.

The optical recording medium shown in FIG. 1 was made by placing -7g unsium oxide (5 + m x 5 pieces x 1 day) on aluminum nitride tarcerate and using RF magnetron sputtering method.
Conditions were controlled so that the aluminum nitride layer contained 2% by weight of magnesium oxide, and after sputtering 1nooX onto a polycarbonate transparent support, a terbium pellet (5%) was sputtered onto an iron-cobalt target.
QIIX5gHx 1 m) YK was deposited, and a 1 m' delbium iron-cobalt based amorphous magnetic film was formed as the recording layer of No. 5 by DC magnetron sputtering, and then magnesium oxide was added to the aluminum nitride layer on top of the magnetic layer No. 5. The structure was manufactured by controlling the various conditions so that the content was 2% by weight, and performing 1000X sputtering.

The optical recording medium shown in FIG. 2 is similar to the case shown in FIG. 1, in which an aluminum nitride layer containing 2 rA'' percent of magnesium oxide (6) is provided on a polycarbonate transparent support (5). After that, the terbium-iron-cobalt system record 1-W of No. 7 was established, and then the aluminum nitride Ii1 of No. 8 was set.
After sputtering at 1400X, an aluminum layer of 9 65
It is designed to be created by noX. The aluminum nitride layer 8 suppresses heat conduction of the terbium-iron-cobalt system recording 1- during recording, reproduction, or erasing.
Since recording and erasing can be performed using low-power light, any material with low thermal conductivity such as ceramics or semimetals such as amorphous silicon will suffice. In addition, since the aluminum 1m of No. 9 uses the magnetic Kerr effect, the original must be transparent! ! Since there is no
Most metals can be used, but if you want to perform playback by fully utilizing the reflection of gold IU-, any metal with high reflectance and corrosion resistance will suffice, so Ti, Or, Ni, Oo, A
Any metal such as g, on, or in may be used.

The optical recording medium shown in Fig. 3 uses glass as a transparent support, and 11 terbium-iron-coalt recording layers are provided directly on 10 glasses, and a first layer is placed on top of that. This is an optical recording medium prepared by sputtering aluminum nitride containing 2% by weight of magnesium oxide of No. 12 in the same manner as in the case shown in the figure. Since the transparent support is glass, the transmittance of moisture and oxygen is low, so terbium-
This is due to the structure in which an iron-cobalt recording layer is provided.

4 to 6 are conventional examples, and the portion of the aluminum nitride layer 1nnnX containing twice as much magnesium oxide as shown in FIGS. It has become.

Figure 1-7 shows the optical recording medium shown in FIGS. 1 to 5, which are the basic configuration of the present invention, and FIGS. 4 to 6, which are conventional examples.
FIG. 4 shows a diagram of changes in pit error rate over time under the environment of nc9n'iRH. a in Figure 7 is the configuration of Figure 1, b
2, C the structure shown in FIG. 3, d the structure shown in FIG. 4, e the structure shown in FIG. 5, and f the structure shown in FIG. 6, respectively. As can be seen from Fig. 7, in the case of the basic configuration shown in Figs. 4 and 5, which are conventional examples, 400 to 50
Cracks occur in the aluminum nitride layer after 0 hours, and even in the case of the structure shown in FIG. 6, the pit error rate changes drastically over time and there is no long-term reliability. It can be seen that the medium has long-term reliability because the pit error rate does not change over time.

Note that the aluminum nitride layer containing metal oxide in this example uses an aluminum nitride target and metal oxide pellets, but a simultaneous sputtering method using an aluminum nitride target and a metal oxide target may also be used. sputtering method using an aluminum nitride target, vapor deposition, ion blasting, OVD (Chemical Va
The film may be formed by a vacuum film forming method such as por deposition.

Further, in this example, polycarbonate and glass were used as the transparent support, but All, 03. MgQ.

'LiF, BeO, YIO,, Zr01. Transparent support made of transparent ceramics such as OaO, acrylic resin,
Transparent resins such as epoxy resins, polyvinyl chloride resins, and polyester resins may also be used.

Further, in FIGS. 1 to 3, between 1.5 polycarbonate transparent support and 2.6 aluminum nitride containing magnesium oxide 1-.

10 glass translucent support and 11 terbium monoiron-
Between the cobalt-based recording layers, an aluminum nitride layer containing 2 weight percent of 2.6 magnesium oxide and a 3.7
between the terbium-iron-cobalt-based recording layer of 7; between the terbium-iron-cobalt-based recording layer of 7; and the aluminum nitride layer of 8; or between the aluminum nitride layer of 8 and the aluminum 1- of 9. Even if there is a layer, the same effect can be obtained, so even if there is an intermediate layer, there is no problem.

Table 1 shows the case where the aluminum nitride layer containing 2% by weight of magnesium oxide is replaced with an aluminum nitride layer containing an oxide of another metal in the optical recording medium having the structure shown in FIG. ,60℃90%RH
The ratio of the pit error rate when performing an environmental test for 1000 hours under the environment and the pit error rate before the environmental test is
The case using a conventionally used protective film is also shown. still.

In Table 1, the metal oxide contained in the aluminum nitride layer was kept constant at 5% by weight, and the layers before and after the terbium-iron-cobalt recording layer were formed under exactly the same conditions for comparison.

From the results in Table 1, Be, Mg, Ca, Sr, Ba, ΔQ
.

Ga, In, 01, Sn, Pb, As, Sb, Te
, Zn, cd.

Ti, V, Cr, Mn, Fe, Y, Zr, Nb, Mo,
La, Oe.

P r + N d + P m e S m m lli
n − G d * T b + D y * Ho
* W r * Select from Hf, Ta, W, Pe, and 08.Also, even if aluminum nitride 1-wo containing one or more metal oxides is used, there is extremely little change in pit error rate over time. Therefore, it can be seen that it has long-term reliability. In addition, from the results shown in Table 1, cost, and non-toxicity, Me, Ca, A1. IGa, In, Si, Sn, Z
n.

It is preferable to use an aluminum nitride layer containing an oxide of one metal selected from Ti, Or, Mn, Y, Zr, and light rare earths, or a metal having a size of 2Pji or more.

Table 1 In the optical recording medium of the structure shown in FIG. The Kerr rotation angle (θki) of the terbium-iron-cobalt layer before the environmental test and the Kerr rotation angle (θk) after the 1000-hour environmental test in an environment of 60°C and 90°RH.
A relationship diagram with the ratio of a) is shown. In Figure 8, g is magnesium oxide, h is aluminum oxide %1 is zinc oxide, j
1 and 2 respectively show cases in which zirconium oxide is contained in the aluminum nitride layer. As can be seen from Fig. 8, the proportion of metal oxide contained in aluminum nitride 1- is 75EO.
11 weight percent or less and 50 weight percent or more
In case 2, since the Kerr rotation angle changes rapidly over time, the metal oxide contained in aluminum nitride IfI is
It can be seen that a value between 0 weight percent is good.□ Figure 9 shows an enlarged view of the vertical axis of Figure 8. 9th
In the figure, k is magnesium oxide, iB aluminum oxide, m is zinc oxide, and n is aluminum nitride II' (i7) containing zirconium oxide.
As can be seen from the figure, the Kerr rotation angle becomes very stable when the ratio of metal oxide contained in the aluminum nitride layer is less than 20% by 1%, especially from 2 to 15%. It has been found that the metal oxide content is very good when it is contained in an amount of 2 to 15% by weight.

In this embodiment, magneto-optical recording is performed which performs recording, reproduction, or erasing using the magnetic Faraday effect and the magnetic Kerr effect.
We have described the terbium-iron-cobalt layer, which is terbium-dysprosium-cobalt, terbium-dysprosium-cobalt, terbium-dysprosium-iron-cobalt, neodymium-iron, and neodymium-cobalt. In addition to rare earth-transition metal layers such as dysprosium-cobalt and indium-teisbrodium-iron-cobalt, oxide magnetic 1@ such as barium ferrite and cobalt ferrite can also be used, and optical phase change type For example, tellurium-tellurium oxide, silver-indium, tellurium-selenium-tin recording layers can also be used.

〔Effect of the invention〕

As described above, according to the present invention, in an optical recording medium in which recording, reproduction, or erasing is performed using one element, at least recording 1- and aluminum nitride Iil containing a metal oxide are formed on a transparent support. By placing C! of record 1-! The present invention has the effect of providing an optical recording medium in which parameters necessary for recording, reproducing, or erasing, such as /N, pit error rate, reflectance, transmittance, θ, and He, undergo extremely little change due to temperature, humidity, or time.

[Brief explanation of drawings]

FIGS. 1 to 6 are block diagrams of the optical recording medium of the present invention, and FIG.
Figures 6 to 6 are configuration diagrams of conventional optical recording media, and Figure 7 shows the optical recording media shown in Figures 1 to 6 at 60°C and 90qbR.
Diagram of pit error rate change over time under H environment, No. 8
The figure shows the Kerr rotation angle θk of the terbium-iron-cobalt layer after 1000 hours of environmental testing at 60°C and 90% RH.
The relationship between the ratio of the Kerr rotation angle θ before the environmental test in a to 1 and the metal oxide content in the aluminum nitride layer. Figure 9 is an enlarged view of the vertical axis of Figure 8. ℃90 R1 (
Terbium-iron after 1000 hours in the environment of
The relationship between the ratio of the Kerr rotation angle θka of cobalt 1- to the Kerr rotation angle θ before the environmental test of 1 and the content of gold IPA oxide in the aluminum nitride layer is shown, respectively. 1... Polycarbonate transparent support 2... Ammonium nitride containing double coating percentage of magnesium oxide 1-5... Record 1@i (Tb-F'e-Co)4...
・Aluminum nitride containing double weight percent of magnesium oxide + * 5... Polycarbonate a photosensitive support 6... Aluminum nitride containing 2 weight percent of magnesium oxide 1-7-[1self-recording 4 (Tb- Fe-Co)8...
Aluminum nitride 1-9...Aluminum layer 1G...Glass transparent support 11...Record 4 (Tb-Fe-Co)12...Aluminum nitride f containing double coating percentage of magnesium oxide - 15...Polycarbonate transparent support 14...
Aluminum nitride layer 15--recording 4 (Tb-Fe-0o)16...
Aluminum nitride layer 17... Polycarbonate transparent support 18... Aluminum nitride layer 19... Recording 1g (Tb-Fe-Co) 20...
Aluminum nitride layer 21...Aluminum 1-22...Polycarbonate transparent support 26-1 (:
Record 1-(Tb-F'e-co)24... Aluminum nitride 1-a... Optical recording medium b having the configuration shown in FIG. 1... Optical recording medium C having the configuration of the second IgJ... Optical recording medium d having the configuration shown in Figure 5... Optical recording medium e having the configuration shown in Figure 4... YfS recording medium f having the configuration shown in Figure 5... Optical recording medium g having the configuration shown in Figure 6...・Optical recording medium h using an aluminum nitride layer containing magi-sium oxide...Optical recording medium 1 using aluminum nitride layer containing aluminum oxide...Using aluminum nitride layer 1- containing zinc oxide Optical recording medium j... Optical recording medium using an aluminum nitride layer containing zirconium oxide k... Nitrogen 1 hyaluminum + 1' containing magnesium oxide! c- Optical recording medium 1 used... Optical recording medium using aluminum nitride 1- containing aluminum oxide m... Optical recording medium using aluminum nitride 1- containing zinc oxide n... oxidation Phototactic recording medium 2 using 1a1 hyaluminum l- containing zirconium fF21cy7;h97muE2! tl-t
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Claims (3)

[Claims] (1) An optical recording medium in which recording, reproduction, or erasing is performed using light, characterized in that an aluminum nitride layer containing a metal oxide and an impurity is disposed on a transparent support. (2) The optical recording medium according to claim 1, wherein the proportion of the metal oxide contained in the aluminum nitride layer is 0.1 to 50% by weight. (3) The metal oxide contained in the aluminum nitride layer is
Be, Mg, Ca, Sr, Ba, B, Al, Ga, In
, Si, Sn, Pb, As, Sb, Se, Te, Zn,
Cd, Ti, V, Cr, Mn, Fe, Y, Zr, Nb,
Mo, La, Ce, Pr, Nd, Pm, Sm, En, G
d, Tb, Dy, Ho, Er, Hf, Ta, W, Re, and Os. optical recording medium.