JPS60234248A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical information recording medium having high chemical stability, large contrast, high C/N ratio and excellent durability by forming a thin film consisting of a mixture added with Se to Ge and Te as an optical information recording film on a substrate. CONSTITUTION:GeTeSe (40-50% Ge, 50-30% Te and 20-1% Se) in which part of Te in GeTe is substd. with Se is deposited by vacuum evaporation, etc. on the substrate 1 consisting of a glass plate, polymethyl methacrylate resin, etc. to form the optical information recording medium 2 which increases the reflectivity in the exposed part irradiated by laser light 3 and permits reproduction by reading of the signal from the difference in reflectivity. The reflectivity in the exposed part is increased by subjecting the film to a heat treatment for about 10 minutes at about 200 deg.C after irradiating the semiconductor laser beam having wavelength (800-850nm) thereon. The magnetic recording medium which has high C/N, large contrast, is hardly deteriorated by oxidation even in high-temp. and high-humidity environment and has high chemical stability is thus obtd.

Description

Detailed Description of the Invention (Technical field to which it belongs) The present invention relates to an optical information recording medium in which the optical characteristics are completely changed by thermal transformation due to the thermal energy of laser light, and a recording film is coated on the entire substrate for recording information. It's a Z-related thing.

(Technical background) Conventionally, optical information recording media have been developed into two types: one in which small holes are formed using the thermal energy of laser light, and the other in which the optical properties (refractive index, reflectance) of the material can be completely changed. I love things. Examples of the former include Te thin film, Te-based compound thin film, chalcogen compound thin film, metal compound q//J thin film, organic color chart thin film, etc. In these cases, the irradiated area is melted and evaporated by the heat of the laser beam to form pits. picture. Therefore, the sensing IK may be insufficient for recording at the same speed rotation, and the small hole opening Z
As a result, the area around the pit may climb up and be disturbed, and residue may remain inside the pit, causing noise.

Another problem is that a protective coating cannot be applied to the thin film. Examples of the latter include chalcogenide thin films, low Te oxide thin films, Sb, Se, Bi, Te, and two-layer thin films. j Gansho 59-137
There is a GeTe thin film proposed as the ``former information recording medium'' in No. 45;! In a recording film that records by completely changing its optical properties through So thermal transformation, the above-mentioned GeTe thin film has excellent properties such as high contrast in a single layer film and B.
(Purpose) The present invention has been made to further improve the stability of the GeTe thin film described above.

(Structure of the invention) In order to achieve this purpose, GeTe 7i
:<Some of the Te in the film is replaced with Se.

(Actually, my sister's example) Below, I will explain the non-invention in detail using diagrams.

FIG. 1 shows one embodiment (1) of the present invention, in which the substrate 2 is a glass plate, polymethyl methacrylate 41it Jlii'',
Polyvinyl chloride resin, polycarbonate 4gg resin, etc. are used, and some of the Te component of GeTe is replaced with Se.
60%, Te: 50-30 hits, Se:
20 to 1φ) The entire recording film 1 is formed by deposition by vapor deposition or sputtering.

In order to perform all recording and playback on the ledger recording medium created in this way,
As shown in FIG. 1, a laser beam 3 is irradiated from a substrate 2.

In this case, a strong laser beam is irradiated and 112 recording is performed, and the exposed area increases the reflectance due to the heat of the laser beam C irradiation. Reproduction is based on two factors: reflectance and readability. The exclusive film of this material is soo g~1200'1 15
Since the reflectance is low in the film thickness range, the largest contrast in this range of film thickness is
Ge, which was replaced by e without g. Te4, Se, k 105
The reflectance and passivity of a glass substrate heated for 10 minutes with a film thickness of 0x are shown. From this figure, under the wavelength of the semiconductor laser (800 to 850111TI), the reflectance before heat treatment becomes 46%, which is approximately 3.4 times; ! S.

By the way, since GeTe is 27 times as large, the contrast is good.
1 sentence yield-4 (~100-reflection semi-transmittance) is about 70 degrees, and it is a Te compound, so it is 2, so the European heat transfer is 7! - Because the rate is low, the absorption of laser light and heat can be carried out efficiently. Therefore, even a single layer film can be subjected to heat treatment using a weak Ji+ such as a semiconductor laser, resulting in a thick contrast and a good C/N ratio (, 4, Iq.; 6 o).
Even if other laser beams such as a He-NC laser are used, high contrast cannot be obtained for the same bζ. GeTeS
e is a mixture of GeTe and Gene, GeTe, Ge
ne nee,,r. Each is sublimable and Z. Therefore,
Even if vacuum evaporation is performed, decomposition into Go, TeXGe, and Se does not occur (formed on the substrate): changes in the implantation of the film are also small.

Next, explain the reflectance change temperature. Figure 3 is Gea.

TeasSe7 was deposited on a glass substrate with a film thickness of 1050 g, and the dependence of the reflectance e and transmittance i on the substrate side at the wavelength of light of 830 nm on the heat treatment temperature is shown. Heat treatment time is approximately 10
As you can see from this figure, both the reflectance and transmittance change greatly between 180 and 200c.

Next, in order to investigate the stability sound of the QeTeSe thin film, Onbo 6
Putting all the samples in 00C humidity 95%, time dependence of thin film transmittance? I tried iJ4. That is Figure 4.

For comparison, graphs of Te thin film and GeTe thin film are also shown. This figure is similar to that of Te thin + [((0 mark), although the transmittance clearly increases rapidly due to oxidation.
x mark) is Yuyaka K (H is 4, Ge a o
Te ansI3) lit! 1 @ 1 (・beat) hasn't changed much. For this reason, GeTeSe is a highly durable material and one of our favorite stones.

(Effect) As mentioned above, due to non-invention, the A-Mitsuharuho record medium is GeTeS.
Since the thin film of E was used for one year, it has excellent contrast, like the GeTe thin film, and has higher chemical stability and stability than the GeTe thin film.

44. Brief description of the drawings FIG. 1 is a sectional view showing an embodiment of a recording medium according to the present invention, and FIGS. 2 to 4 are diagrams showing all characteristics of the medium according to the present invention. Diagram 01・Fist・Substrate 2...Recording film 3110 Laser patent applicant Nippon Columbia Co., Ltd.

Claims (1)

[Claims] In an optical information recording medium, a thin film is formed on a substrate, and a portion with changing optical characteristics is formed in the thin film by energy such as heat, and information is recorded. A mixture of selenium and carbon fiber has all the characteristics of an optical information recording medium.