JPS6228940A - Information recording medium - Google Patents

Abstract

PURPOSE:To prolong the shelf life of the titled information recording medium and to maintain the writing characteristic for a long period by forming a barrier layer consisting of the anodization product of a recording film between the recording films and preventing the diffusion between the recording films at ordinary temp. CONSTITUTION:A recording layer is composed of a metallic thin film 13a as the first recording film, a barrier layer 13b formed by dipping the thin film 13a in an anodizing soln., passing a specified electric current and anodizing the film and a semiconductor thin film 13c as the second recording film. When a laser beam is irradiated on an optical disk having such a layer 13b from the substrate 11 side, a single layer 16 having different reflectivity is formed and information is read by utilizing the difference in the reflectivity. Besides, while a laser beam is not irradiated, the diffusion of the thin films 13a and 13c is blocked by the layer 13b, hence the shelf life of the optical disk is prolonged and the writing characteristic can be maintained for a long period.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to an information recording medium in which information is recorded by locally mixing a plurality of recording films stacked on a support substrate. .

[Technical Background of the Invention and Problems thereof] In recent years, optical disks have been used as recording media for ships entering the military. An optical disc on which information can be written by converting the disc into a disc has been proposed (Japanese Patent Application No. 59-14058).

FIG. 3 is a sectional view schematically showing the structure of this J-type optical disc.

This optical disc consists of a transparent substrate 1 and a substrate (J
This recording layer 2 further comprises two types of recording films having different optical attenuation coefficients, that is, a complex refractive index n.
) - i k ) and a second recording film 4 having a complex refractive index n2-il<2.

The initial reversal rate f? of such a recording layer 2 is? + indicates the boundary between the substrate 1 and the first recording film 3, the boundary between the first recording film 3 and the second recording film 4, and the second recording film 4, as shown in FIG.
It is used as the vector sum of Fresnel reflection coefficients r1, r2, and r3 occurring at three boundaries of the external world 5 and the outside world. The vector length of each Fresnel reflection coefficient and the phase difference between them are mainly determined by the double refractive index of the first recording film 3 and the second recording film 4 and their thicknesses dl and (j2). Therefore, the initial reflectance Rrl can be set to a desired value by setting the thicknesses dl and d2 of the materials of the first and second recording films.

This J, the initial foul rate set to
The Rake 9 beam 6 with an intensity of (above the recording threshold determined by the relative diffusion coefficients when the first and second recording films 3.4 and 44 are heated) produces spora 1 to black. When used, the first and second recording films 3.1 in that part are in phase 11.
The new single layer 7 is formed by diffusing and annihilating the boundaries. As a result, the Fresnel foul coefficient 1" 21ci is lost, and the foul rate Rr of the part where the recording was performed is i, j. The Fresnel foul coefficients r4 and r5 are The non-rej changes to the combined value of solid 1 to ().

However, recording on this optical disc is performed by converting the ratio of the recording layer 20 from R1 to Rr based on the above-described mechanism.

Therefore, in such a recording layer 2, there is a threshold E/redogo directivity of the rake beam required for recording by 1 degree, and
The ratio of i rate R + do Rr is large, and
There is very little interdiffusion between the 3.4 and 2nd records, and the 4F layer that intersects is highly sensitive as a recording layer, and has a large readout arch, spanning only 51 lengths and 1!11. It is required to be stable.

However, since a recording layer with a low threshold value of the ray IJ'' beam required for recording at room temperature (this makes it easier to suppress mutual diffusion), it is possible to There was a problem that it could not withstand storage.

[Objective of the Invention] The present invention was made in order to cope with the circumstances described in 1. B provides an information recording medium using a recording method.

[Nυ of the invention] In order to achieve the objective of l-opening, the present invention includes a supporting substrate and a laminated layer formed on this supporting substrate 1- and mixed with each other or l;j;
At least -b whose optical constants change by alloying
In an information recording medium in which J-type recording is performed by forming a two-layer recording film 41 and locally mixing or alloying the recording film, this recording 1143 between the recording films is performed. ] or the oxidation product J, forming a barrier layer.

[Embodiments of the invention] The present invention will now be described with reference to the drawings.

FIG. 1 is a sectional view showing one embodiment of the present invention.

However, the information recording medium of this embodiment is a substrate 11 made of PMMA (polymethyl methacrylate), etc., and is made of a plasma polymerized film that avoids plasma polymerization of methane gas, which is formed to avoid adhesion. transparent underyaw layers 1 to 12, and a recording layer 1 formed thereon.
3, and A17 pull 1' formed on top of this! le [
]-1 to layer 1/l.

Further, this recording layer 13 has a thickness of 20 mm as a first recording film.
A metal thin film 13a made of Af, Au, Pb, Sn, Te, etc. of about 0 to 400 people is immersed in an anodizing solution made of about 10% sulfuric acid solution, and a constant current is applied to form the metal thin film 13a. Thickness 3 formed by anodizing the surface layer of 13a
The firmness of 0 to 100 culms) 7 layers 131) and the thickness of -1(・1 stone as the second recording film 20
A semiconductor film 13C of 0 to 300 Qe, 3i, etc. is formed.

At this time, if the thickness of the burr N7 layer 13F) is thinner than 10 layers, the effect as burr~7 will be low, and if it exceeds 100 layers, a rake beam with high T energy will be required to write information. The above range is preferable.

In addition, this Paris S' @ i, 11 is very thin, so positive)
~ The growth of the oxide film is cut off before the large number of pores characteristic of the oxide film appear on the surface, and there is no need for immediate hole treatment.

In addition, the oxide film of the metal thin film formed by anodic oxidation is
If you do not cover the surface of the metal evenly and there will be gaps in some areas,
7 layers (J-, 1, r).On the other hand, its volume is significantly more difficult than that of any metal. It is preferable to form it with a metal that does not cause the γ phenomenon, such as Af, PB, Ni, etc.

In this example, sulfuric acid was used as the anodizing solution.
January'7J
You can also do that.

This optical disc with 7 layers is the substrate 1.
1 side, when the relay beam 1B is illuminated, thermal energy is transmitted through the transparent substrate 11 to the metal barrier film 13a and the semiconductor thin film 13G, causing these layers to melt or Diffused to form metal thin film 13a and semi-nine body thin film 13
cy mixed or alloyed.

Therefore, in the area facing the front side of the laser beam 15, the two layers of material are mutually diffused as shown in FIG.
is formed, and the fault rate of this single layer 16 is 1, which is clearly blamed on the fault rate of the part where L recording was not performed, so it is possible to read information using this difference in the fault rate. can.

When the laser beam is not directed forward,
Burr~71 flash 13b is metal thin film 13a and semiconductor thin film 13
Since it impairs the diffusion of G, it is possible to improve the storage life of the optical disk and maintain the ejection and ejection characteristics for a long period of time.

[Results of the Invention] As explained above, according to the present invention, in an information recording medium in which information is recorded by locally mixing and alloying a plurality of recording films, this recording is performed between the recording films. Because seven layers of oxidation products are provided on the first layer of the film, diffusion between the recording films at room temperature is prevented, which reduces the shelf life of the information recording medium and Including special !4 can be maintained for a long time.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a sectional view showing the recording state of the same embodiment, and FIGS. 33, 33, and 4 are sectional views of a conventional information recording medium. It is a diagram. 11... Substrate (supporting base) 13a.
...Metal thin film (recording film) 13[)...Vari 1 layer 13G...Semiconductor thin film (recording film) Applicant
Co., Ltd. Ne1 Toshiba Agent Ben Sokujusu +h Ih -Figure 1Figure 2Figure 3Figure 4

Claims (1)

[Claims] (1) It has a support base and at least two recording films that are laminated on the support base and whose optical constants change when mixed or alloyed with each other, and the recording films are locally mixed or alloyed. What is claimed is: 1. An information recording medium for performing recording, characterized in that a barrier layer made of an anodic oxidation product of the recording film is formed between the recording films.