JPH03262684A - Optical recording medium - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] To explain in more detail regarding optical recording media, recording and erasing are performed by reversibly changing the crystalline state of the recording medium by irradiating and heating it with laser light. With regard to rewritable phase-change optical recording media, we aim to provide an InSb-based optical recording medium that increases erasing speed and maintains good signal quality of recorded data. In the phase change type rewritable optical disk, the composition ratio "x" of antimony is 0.5 to 0.53 and vanadium oxide (
VO2) is added in an amount of 5 to 15 at%.

[Industrial application field]

The present invention relates to an optical recording medium, and more specifically, the present invention reversibly changes the crystalline state of the recording medium by irradiating and heating it with a laser beam, and correspondingly changes the optical reflectance of the recording medium. The present invention relates to a rewritable phase-change optical recording medium that can perform recording and erasing using change.

Such a rewritable optical recording medium used in an optical disk has a data erasing function added to a data recording function, and data can be erased in a short time to increase the data processing speed. For this reason, there may be problems with saving recorded data, and carrier-to-noise (C
/N ratio) became low, making it insufficient to achieve both signal quality and erasing speed.

[Conventional technology]

Optical disks using InSb thin films are already known as phase-change optical recording media, and germanium oxide (Ge
The applicant has proposed the addition of O7) in Japanese Patent Application No. 1-1461.
No. 65 (filed on June 8, 1999).

Optical discs using InSb-based thin films as recording films, for example,
It consists of a glass substrate, a photopolymer base protective film with track grooves thereon, a recording film of InSb or GeO□-doped InSb, and a photopolymer top protective film on the recording film.

[Problem to be solved by the invention]

In order to rewrite data, it is necessary to erase the data by one degree, and for this purpose, laser power is irradiated at a crystallization level intermediate between high power for writing and low power for reading. In order to erase data, the signal quality of conventional InSb recording media was poor, and the same location had to be irradiated with an erasing laser several times, which took a long time.

An object of the present invention is to provide an rnsb-based green optical recording medium that increases the erasing speed and maintains good signal quality of recorded data.

[Means to solve the problem]

The above-mentioned purpose is to provide indium-antimony (Ir++-X
Sbx) In a phase change type rewritable optical disk, this is achieved by an optical recording medium characterized by:

[For production]

When vanadium oxide (VO2) is added to InSb, I
By promoting the crystal recovery of nSb, recorded data can be erased by two erasing laser irradiations, as will be described later, and the C/N ratio at the next writing will be 42 dB or more.

〔Example〕

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below through experiments including examples of the present invention and comparative examples with reference to the accompanying drawings.

Optical disks having InSb thin films with varying amounts of η VL added were fabricated as follows.

A base protective film of photopolymer (2p) having track guide grooves was formed on a glass substrate. This is done with an electron beam (
EB) After putting the In and S into separate crucibles after putting them into the chamber of the vapor deposition equipment and making the chamber a vacuum.
b and VO2 are simultaneously heated and evaporated with an electron beam. As a result, VO□ was added onto the underlying protective film (In
A recording film was formed. At that time, (1) the composition ratio of InSb was changed to In4sS
b5. The amount of vO□ added was varied while keeping it constant (In4
9Sls+) +-y(V[Iz)y film to be formed.
(corresponding to the figure), and (2) (In, −, 5t) x) so(
Vl]. ) A to film was formed (corresponding to FIG. 2).

Next, after taking out the substrate from the EB evaporation apparatus, a photopolymer upper protective film was formed on the recording film to complete an optical disc.

Writing was performed on the thus produced optical disc by irradiating it with a laser beam under the following conditions.

Laser Par"7-: 8.QmW Irradiation frequency + 0.4MH2 Optical disk rotation (peripheral speed 11.6m/s) Next, the written data is read out by irradiating the optical disk with the same rotational speed with a laser with a power of 1.5mW. , the C/N ratio at this time is the composition (In49Sl)SI)90(
In the case of a recording film of VO□) to, it was 44 dB. Reading was carried out in the same manner for each optical disk, and the obtained C/N ratios are shown in FIGS. 1 and 2. In addition, in the 1nassb5+ recording film without adding vO□, C/
The N ratio was 35 dB.

In order to erase the written data, a laser with a power of 4 mV was irradiated, and the number of times of erasing irradiation necessary for erasing was investigated, and the results are also shown in FIGS. 1 and 2. Data erasure here means that the erased data is 15 dB or less when read out as described above. Composition (Tna9Sbs+)g.

(VI]2) C/
N becomes 11 dB, meaning that 33 dB is also erased.

As can be seen from Figures 1 and 2, the C/N ratio is 42
dB or more is (Ins9Sbs+) +-y(
When "y" of VOa)y is in the range of 0.05 to 0.15 (i.e., 5 at% to 15 at%), and
(In 1-xsbx) s.

(7 shares,) 1o “x” is 0.5 to 0.53 (50a
t% to 53at%). In these ranges, the number of erase irradiations is also two (or three) times, which is less than outside the range.

〔Effect of the invention〕

As described above, according to the present invention, an optical recording medium in which vO□ is added to InSb has an improved C/N ratio and requires fewer erasing irradiations (that is, the erasing speed can be improved by reducing the erasing time. This makes it possible to improve the performance of optical discs.

[Brief explanation of drawings]

FIG. 1 shows that the optical recording medium is (InasSbs+) I-y
FIG. 2 is a graph showing the relationship between the composition ratio "y", the C/N ratio as an optical disk, and the number of times of erasing irradiation in the case of (V[]z)y. )so(V
ow)t. 3 is a graph showing the relationship between the composition ratio "x", the C/N ratio as an optical disk, and the number of times of erasing irradiation in the case of FIG.

Claims (1)

[Claims] 1. Indium-antimony (In_1_-_xSb_
x) An optical recording medium in which the composition ratio "x" of antimony is 0.5 to 0.53 and 5 to 15 at% of vanadium oxide (VO_2) is added in a phase change type rewritable optical disc. .