JP2871724B2 - Optical disk media - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an optical disk medium, and
The present invention relates to an optical disk medium capable of performing reproduction.

[Conventional technology]

For conventional optical disk media, consideration is given to film forming properties when manufactured at a temperature near room temperature, write efficiency for writing signals with small photothermal energy, and read efficiency for reading written signals with good S / N ratio. However, an amorphous thin film utilizing a phase transition from amorphous to crystalline has been attracting attention.

Generally, a Tb / Fe / Co-based magnetic thin film is used as the amorphous thin film.

FIGS. 2 (a) and 2 (b) are a partial plan view and a radial cross section showing an example of the related art.

The optical disk medium shown in FIGS.
And an active area (recording area) 2 in which a groove for guiding the optical system is cut and in which information is written, and inactive areas 3 on the inner and outer circumferences sandwiching the active area 2 of the substrate 1. And a protective film 6 for protecting the recording film 4.

[Problems to be Solved by the Invention] However, such a conventional optical disk medium described above uses a TbFeCo-based magnetic material for a recording film, and therefore has poor corrosion resistance and is corroded in a humidity atmosphere, resulting in deterioration of magnetic characteristics. Disadvantageously occurs. This disadvantage is a common problem not only in magneto-optical media but also in optical recording media. In order to eliminate such defects, the recording film is covered with an inorganic thin film having a gas barrier property such as oxygen, or a multifunctional coating resin film, or an optical disc medium having a laminated structure in which the recording film is sealed. However, at present, the effect of preventing corrosion of the recording film cannot be obtained.

By the way, it is said that the corrosion of the magneto-optical recording medium is caused by contamination of the substrate, humidity, oxygen, etc. There are two modes, one that corrodes from the surface of the substrate (recording film) and the other that corrodes from the edge of the recording film. is there. The latter mode is common.
Corrosion occurs from the edge of the recording film, and it proceeds in the direction of the active area affected by the internal battery effect due to the corrosion reaction, so that the edge of the recording film formed on the substrate extends outside the active area. However, if corrosion occurs at the edge of the recording film, there is a disadvantage in that the quality of the magneto-optical medium is significantly reduced eventually over the entire area of the recording film as described above.

[Means for solving the problem]

The optical disc medium of the present invention includes a substrate, a recording film formed on the substrate and including an active area where information is written and an inactive area where information is not written, and a protective film that covers the recording film. The recording film is annularly separated by a gap only in the inactive area, and the inactive area exists only in the outermost and innermost areas on the substrate.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention. First
The optical disk medium shown in FIG. 1 includes a substrate 1, a recording film 4 including an active area (recording area) 2 and an inactive area 3, a gap 5 for separating the recording film 4, and a protective film 6. You.

First, the recording film 4 covers the surface of the substrate 1 provided with the groove for guiding the optical system servo, as in the conventional example. Here, paying attention to the inactive area 3, the recording film 4 has a gap 5 separated in a donut shape.

Needless to say, the protective film 6 includes the active region 2 and the inactive region 3.
Further, it is coated so as to cover the recording film 5 having the gap 5.

〔The invention's effect〕

The optical disk medium of the present invention is provided with a donut-shaped recording film and a gap in an inactive area provided outside the active area, whereby the propagation of corrosion generated from the end of the recording film and the internal battery effect due to the corrosion reaction are caused. Since the propagation of corrosion can be prevented, there is no effect on the recording film of the active region due to corrosion from the end of the recording film, and there is an effect that the long-term reliability can be significantly improved.

Further, the effect can be further enhanced by increasing the number of combinations of the recording film and the gap in the above-described gap.

In addition, even if it is provided discontinuously on the outer periphery of the substrate described above, the same effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIGS. 2 (a) and 2 (b) are a partial plan view and a sectional view showing an example of the conventional art. 1 ... substrate, 2 ... active area, 3 ... inactive area, 4 ...
... recording film, 5 ... gap, 6 ... protective film.

Claims (1)

(57) [Claims] 1. A semiconductor device comprising: a substrate; a recording film formed on the substrate, the recording film including an active area in which information is written and an inactive area in which information is not written; and a protective film covering the recording film. An optical disk medium, wherein the recording film is annularly separated by a gap only in the inactive area, and the inactive area exists only in the outermost and innermost areas on the substrate. .