JPS63201932A - Production of optical recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical recording medium which has good weatherability, high sensitivity and good signal quality by passing vapor contg. tellurium and selenium through a gaseous atmosphere contg. gaseous nitrogen converted to plasma and forming a recording layer essentially consisting of the tellurium and selenium and nitrogen on a substrate. CONSTITUTION:This recording medium is so formed as to have at least the substrate 1 and the recording layer 21 which is partly selectively removed by a laser light to record information and is formed on the substrate 1. The vapor contg. the tellurium and selenium is passed through the gaseous nitrogen converted to plasma by high-frequency electric power or the gaseous mixture contg. the gaseous nitrogen, by which the recording layer 21 essentially consisting of the tellurium and selenium as well as nitrogen is formed. Since the recording layer 21 is essentially formed of the tellurium and selenium as well as nitrogen in such a manner, the optical recording medium having good weatherability and high sensitivity for the signal of good quality is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of manufacturing an optical recording medium, particularly a method of manufacturing an optical recording medium for manufacturing an optical recording medium on which information can be recorded and reproduced using a laser beam. Regarding.

[Conventional technology]

2. Description of the Related Art Generally, optical disk memories, which record and reproduce information on a medium using laser light, have a high recording density and are therefore well-known as large-capacity recording devices. Tantalum and lead were first used as materials for this optical recording medium (
Science (5science) 154.1550.19
66)). Various materials have been used since then, but chalcogen elements such as tellurium or their compounds are often used (Japanese Patent Publication No. 47-26897), and tellurium-selenium alloys are particularly commonly used. (Japanese Patent Publication No. 54-41902, Japanese Patent Publication No. 7919-1982, Japanese Patent Publication No. 57-56058).

In recent years, in order to downsize recording devices, semiconductor lasers have been used as laser light sources. Semiconductor lasers have an oscillation wavelength of around 8000λ, but tellurium-selenium based lasers
The alloy is relatively well suited to this wavelength band, with moderate reflectance and moderate absorption (phys-stat solidi, 7.189°1g64).
-sol-e, 189.1964)).

An example of an optical recording medium manufactured by the present invention and a conventional optical recording medium manufacturing method using this tellurium-selenium alloy as an optical recording layer has a structure as shown in FIG.

A recording layer 21 made of a tellurium-selenium alloy is provided adjacent to the substrate 1. The recording laser beam is focused and irradiated onto the recording layer 21 through the substrate 1, and pits 22 are formed. The substrate 1 is made of synthetic resin such as polycarbonate, polyolefin, polymethylpentene, acrylic, or epoxy resin, or glass. Usually, pits are recorded on the substrate 1 in a concentric or spiral manner at regular intervals with high accuracy. A guide groove is provided.

When light enters a groove with a width similar to the diameter of the laser beam, the light is diffracted, and as the beam center shifts from the groove, the spatial distribution of the intensity of the diffracted light changes.This is detected and the laser beam is directed to the center of the groove. A busy servo system is constructed. The width of the groove is usually 0.3 to 1.3 μm, and the depth of the groove is set in the range of 1/20 to 1/4 of the wavelength of the laser used. A servo system is similarly configured for condensing light.

Information is read by irradiating a laser beam with a lower power than that used during recording so that it passes over the bits1.
This is done by detecting changes in reflectance due to the presence or absence of bits.

[Problem that the invention seeks to solve]

However, with the tellurium-selenium alloy film, recording and reproducing signals of good quality could not be obtained.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing an optical recording medium that has good weather resistance, high sensitivity, and can obtain signals of good quality. shall be.

[Means for solving problems]

The method for manufacturing an optical recording medium of the present invention is a method for manufacturing an optical recording medium having at least a substrate and a recording layer formed on the substrate, a portion of which is selectively removed by a laser beam to record information. By passing vapor containing tellurium and selenium through nitrogen gas or a mixed gas containing nitrogen gas that has been turned into plasma by high-frequency power, a recording layer containing tellurium, selenium, and nitrogen as main components is produced. configured to do so.

[Effect]

By making the recording layer mainly composed of tellurium, selenium, and nitrogen, an optical recording medium with good weather resistance, high sensitivity, and signals of good quality can be obtained. The reason why this optical recording medium has high sensitivity and can obtain signals of good quality is that a compound of nitrogen and chalcogen elements is generated in the film, which is caused by the formation of small holes, which is the initial stage of pit formation recording. This is because irradiation is performed with relatively low recording power.

〔Example〕

Next, examples of the present invention will be described.

A specific example of the optical recording medium manufacturing method of the present invention is to place a polycarbonate resin disk substrate with a guide groove of 15 mm in inner diameter and 1.2 strokes in thickness, which has been annealed at 100° C. for 2 hours, into a vacuum apparatus, ″@Torr or less.As an evaporation source, tellurium was placed in the first resistance heating boat.
Selenium was placed in a second resistance heating boat. Introducing a mixed gas of nitrogen and argon to the high frequency coil at 13.56
Tellurium and selenium are simultaneously evaporated from each boat while applying MHz high-frequency power to generate plasma, and by passing through the plasma, part of the tellurium and selenium is nitrided and deposited on the substrate. A thick layer of tellurium, selenium, and nitrogen having a ratio of tellurium, selenium, and nitrogen in atomic percent of 76:19:5 was formed into a 260% thick layer. Thereafter, it was stored for 12 hours in an environment with a temperature of 85° C. and a relative humidity of 90% to produce an optical recording medium. The reflectance of this optical recording medium at a wavelength of 8300λ when incident on the substrate was measured and was approximately 29%. Semiconductor laser light with a wavelength of 5aoo& is incident through the substrate, and a laser beam of 1.6μ is applied onto the recording layer.
Narrow down to about mφ, medium linear velocity 5.65 m/sec
, recording frequency 3.77MHz, recording pulse width 70ns
ec, recorded under the conditions of recording power 7.5 mW, 0.7
Regeneration was performed at mW. The ratio of carrier to noise (C) in the band @30KHz was 48dB, which was very good.

After storing this optical recording medium in an environment of 70°C and 80% high humidity for 60 hours, the above characteristics were examined, but there were no changes.
It was confirmed that the optical recording medium has excellent weather resistance.

The thickness of the recording layer is preferably in the range of 100k to 1000mm from the viewpoint of recording and reproducing characteristics, and the selenium content is 2% in terms of atomic percent) [The thickness of the recording layer is preferably less than 40% from the viewpoint of recording and reproducing characteristics and weather resistance. The content of nitrogen is desirably 2% or more and less than 20% in terms of atomic percent from the viewpoint of recording/reproducing characteristics and weather resistance.

〔Effect of the invention〕

The optical recording medium manufacturing method of the present invention has the advantage that it is possible to manufacture an optical recording medium that has good weather resistance, high sensitivity, and good signal quality.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing an example of an optical recording medium manufactured by the present invention and a conventional optical recording medium manufacturing method. 22hi′, :,,g

Claims (1)

[Claims] A substrate is placed in a gas atmosphere containing at least nitrogen gas that has been turned into plasma by high-frequency power, and vapor containing tellurium and selenium is passed through the gas atmosphere, and a vapor containing tellurium, selenium, and nitrogen as main components is placed on the substrate. A method for producing an optical recording medium, comprising producing a recording layer comprising: