JPS6256583B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an optical information recording/reproducing member used in a device that records and reproduces information at high density using light such as a laser beam and thermal energy.

Recording of high-density information using laser beams,
Techniques for performing regeneration are known. As a recording medium used in such a recording/reproducing device, there is one in which a thin film mainly composed of tellurium oxide TeOx ₁ (0<x ₁ <2) is provided on a substrate. (JP-A-50-46317, JP-A-50-46318, JP-A-50-46319, U.S. Pat. No. 3,971,874), the additive component is PbOx ₅ (0< _x5 <1 ), SbOx ₆ (0＜ _x6 ＜
1.5), VOx ₇ (0< _x7 <2.5), etc. are used. Such a recording medium can obtain a large change in transmittance when irradiated with a light beam for reproduction.

However, when trying to downsize and simplify recording and playback equipment, there is a limit to the output of the laser light source that can be used, so it is recommended to use small He-Ne laser oscillation equipment, semiconductor laser oscillation equipment, etc. with an output of 20 mW or less. To perform recording and playback using TeOx (0<x<
A recording medium equipped with a thin film containing 2) as a main component has insufficient sensitivity. Furthermore, when information is reproduced by changing the amount of reflected light, a sufficient amount of change cannot be obtained.

Considering the optical transmission efficiency of the optical system used in recording and reproducing equipment, the state changes with He-Ne laser light or semiconductor laser light with an energy density of 50 mJ/cm ² or less, and its optical characteristics greatly change. Change is desirable.

The present invention provides a method for manufacturing an optical information recording/reproducing member that can improve sensitivity and changes in optical properties due to recording by improving conventional materials.

In order to utilize the state change of the recording medium due to temperature increase due to light irradiation absorption, etc., as a method to increase the sensitivity, the main component TeOx ₁ , 0<x1<2.0 (TeO ₂
(Melting point Tm = 733°C) There is a method of lowering the threshold temperature for state change by applying additive materials with low melting points.

For example, TlOx ₂ 0 < x ₂ < 1.5 (Tl ₂ O melting point Tm = 300
℃) is used.

On the other hand, there is a method of increasing the refractive index of the medium in order to increase the change in optical properties accompanying the state change, and for this purpose, an additive material with high ionic polarizability and high density is used.

For example, BiOx ₂ , InOx ₂ (0<x ₂ <1.5), etc.

The optical information recording/reproducing member of the present invention contains a mixture of a low oxide of tellurium TeO (considered to be a mixture of Tl and O ₂ ) and a low oxide of thallium Tl ₂ O, as well as an elemental metal and a semimetal tellurium. , bismuth, and indium.

These additive materials increase the absorption coefficient and refractive index of the film, improving sensitivity and improving the amount of change in reflectance.

To construct the optical recording medium, a glass plate, or a sheet or film made of a synthetic resin such as polymethyl methacrylate resin, polyvinyl chloride resin, polycarbonate resin, or polyethyl terephthalate resin is used as a suitable substrate for vapor deposition. Further, it is also possible to use a material coated with an appropriate surface coating in order to adjust the surface thermal constant, etc. The main raw material tellurium oxide and the additive raw material oxide are powdered and mixed, and then melted in an air atmosphere in a quartz crucible or a platinum crucible. A few minutes is sufficient for the melting time. The mixed and melted raw material oxides are rapidly cooled in air to obtain a yellowish to black glassy substance. This mixed solid solution is powdered and used as a raw material for vapor deposition.

Vapor deposition is performed using a resistance heating vapor deposition method using a boat made of metal such as tungsten or molybdenum. At this time, the mixed solid solution oxide of the raw material is melted in the boat, further subjected to a reduction reaction by the metal boat, evaporated, and deposited on the substrate. The vapor-deposited film thus obtained is a thin film exhibiting a pale yellow to yellowish transparent color.

The film thickness used is in the range of 300 to 3000 Å.

The degree of vacuum during vapor deposition was 5 x 10 ^-5 mmHg, and even if the vapor deposition conditions were changed, there would be no significant difference in the properties of the optical recording medium obtained.

The composition of the obtained vapor-deposited recording film is low oxide TeO
And, the main component is low oxide Tl ₂ O, and this,
It consists of at least one of the additive elemental metals and semimetals Te, Bi, and In.

As shown in the embodiment of FIG. 1, the member of the present invention includes a light-absorbing thin film, that is, a thin film photosensitive layer made of a low oxide containing Bi, Te, or In, on the surface of a base material 1. 2 was formed.

Depending on the purpose of use, on the thin film photosensitive layer 2,
Furthermore, a protective layer 3 is provided.

The base material 1 may be metal such as aluminum, copper, etc., glass such as quartz, pyrex, soda glass, etc., resin, ABS resin, polystyrene, acrylic, vinyl chloride, etc., and the transparent film may be acetate, Teflon, polyester, etc. Can be used. Among these, when polyester film, acrylic plate, etc. are used, they have excellent transparency and are effective in optically reproducing the formed signal image.

Next, an optical information recording/reproducing device using the member of the present invention will be explained.

FIG. 2 shows an embodiment in which a semiconductor laser λ=8200 Å is used as the laser light source.

Semiconductor lasers generally emit laser light with a large beam spread of ±20 degrees, so first and second lenses are used to shape the beam into a spot.

The emitted beam from the semiconductor laser 4 is converted into a condensed parallel beam 6 by a first lens 5, shaped into a spot beam 8 by a second lens 7, and is converted into a low oxide beam.
A recording member made of a base material 10 provided with a light-absorbing thin film recording film 9 containing at least one of Bi, Te, and In is irradiated with a light intensity corresponding to a signal.

When using a semiconductor laser, unlike a gas laser, internal modulation is easy and an optical modulator is not required.

The area exposed to light turns black and the reflectance changes, allowing recording to take place.

Recording is possible by irradiating light either from the front side of the film or from the back side of the film through a transparent base material.

Next, a method for reproducing information from a signal recorded as in the present invention will be described.

The information recording thin film is light brown in an unwritten state, and becomes grayish brown or black in a written state, and the optical density increases and the reflectance changes.

When reproducing signals, reflective optical signal reproduction is possible.

In FIG. 3, a tungsten lamp, a He--Ne laser, a semiconductor laser, etc. can be used as the illumination light 11.

First, the light 13 that has passed through the half mirror 12 is focused by the lens 14 and illuminates the signal image 15.

Next, the light reflected from the signal image 15 is transmitted to the lens 1
4 and is reflected by the half mirror 12,
The reflected light 16 enters a photosensitive diode 18 through a lens 17.

The intensity of the reflected light 16 increases 2 to 3 times or decreases to 1/2 to 1/3 when a signal image is irradiated compared to when there is no signal, and this change is detected to perform signal reproduction. It is something.

In the above apparatus, in both recording and reproducing of signals, it is possible to irradiate the film surface side of the recording member and the back side, that is, the base material side.

Next, details of the method for manufacturing the optical information recording/reproducing member according to the present invention will be explained.

Example A component represented by the following compositional formula is used as an example of a starting material for vapor deposition.

(TeO _{2 100-X} Tl _{2 O X} ) _100- Y M Y At least one of Bi, Te, and In is used.

The starting raw materials are obtained by melting and heat-treating TeO ₂ and Tl ₂ O in a predetermined composition ratio in advance, mixing the single additive materials therein, and heat-treating the mixture for about 8 hours near the melting point of each additive material.

A procedure for forming a light-absorbing recording member using this will be described.

Using the generation system shown in Figure 4, the degree of vacuum in the vacuum system 19 is
Choose between 10 ^-3 mmHg and ^{10 -6} mmHg.

As the base material 20 for vapor deposition, metal, glass, organic film, paper, etc. can be used, and it is provided on the substrate support stand 22. The heating vapor deposition container 27 can be a tungsten boat, a titanium boat, a quartz crucible, or the like. 27 or a heating coil heater 24 is coupled to the electrode 23 and heated using a power source 25.

Another method is to directly heat the mixture with an electron beam or the like.

The heating temperature is selected within the range of 200°C to 1000°C.

Under the above vacuum degree and heating temperature conditions, the vapor deposition raw material 26 in the container 27 is heated, reacts, melted, elevated and evaporated, and a light-absorbing recording film 26 is formed on the vapor deposition substrate 20.
Form as 1. The thickness of the deposited film can be adjusted depending on the amount of raw materials, the deposition area, etc., and can be easily controlled within the range of 30 Å to 2 μm.

Part of the starting raw material undergoes a reduction reaction during the vapor deposition process.
TeO ₂ becomes a low oxide TeO, and the deposited film is mainly composed of this low oxide TeO and low oxide Tl ₂ O, and a light-absorbing film with the addition of an elemental metal or metalloid M. It is formed by

Preferably TeO and
A low oxide solid solution of Tl ₂ O is prepared by adding additive materials, and a quartz crucible is used as the container 27 for heating vapor deposition. To explain a specific example,
TeO _{2 86} and Tl ₂ O ₁₄ are heated and melted at 800°C in advance to form a glass-like material, and then a single substance is added to this.
Add 10 at% Bi (TeO _{2 86} Tl ₂ O ₁₄ ) to create a starting material for vapor deposition of ₉₀ Bi ₁₀ . Place this in a heated vapor deposition container,
It is heated to 900° C. in a container with a vacuum degree of 5×10 ⁻⁵ mmHg and vapor-deposited onto the substrate to form a light-absorbing recording film. As a result of analyzing the formed recording film, the additive material elemental Bi was found to be 1at%, and (TeO
It turned out to be a recording film of ₈₆ Tl ₂ O ₁₄ ) ₉₉ Bi ₁ .

The thin film recording member used in the present invention is characterized by a large change in optical properties during recording, particularly a large change in reflectance ΔR.

FIG. 5 shows the relationship between the change in reflectance ΔR after light irradiation of films using Bi, Te, and In as additive materials and the amount Y of addition.

As the starting raw material composition, select (TeO _{2 807} Tl ₂ O ₂₀ ) _100-Y M _Y and add amount Y.
10, 20, 30%.

Curve a ₁ in FIG. 5 is for Bi selected as the additive material, curve a ₂ is for Te as the additive material, and similarly curve a ₃ is for In as the additive material.

ΔR of addition amount Y=0 for irradiation with the same amount of light
Compared to the above, the amount of change ΔR in reflectance is large in the case of a single metal or a single metal semimetal added.

When the additive material is Bi, as shown by curve _a1 , the amount of change ΔR becomes maximum at the addition amount Y=10, and Δ
R reaches 35%. When the additive materials are Te _and In, the amount _of addition is Y=
ΔR is maximum at 20, 23% and 37%, respectively.
become.

Here, as the amount of change ΔR, the reflectance in the unrecorded state is R ₁ (%), and the reflectance after recording is R ₂ (%).
and choose the amount shown by ΔR=R ₂ .R ₁ (%).

Compared to ΔR=12% when no additive material is used, the amount of change ΔR increases two to three times in the film with the additive material added.

Next, as the sensitivity characteristics of the film, the relationship between the amount of irradiation light and the amount of change in reflectance is shown in FIG.

Curve a ₀ is an example when no additive material is used, and curves a ₁ , a ₂ , and a ₃ are additive materials such as Bi, Bi, and a 3 , respectively.
It uses Te and In.

At any irradiation light intensity, the change in reflectance of the film using the additive material is large, and the film using Bi and In as the additive material exhibits the characteristic that the change ΔR becomes large especially in the region where the irradiation light intensity is large. When Te is selected as the material, as shown by curve _a2 , the amount of change is already large in the region where the amount of irradiation is small.

In both cases, the film curve a0 using additive material gives a larger amount of change than the film curve a ₀ without additive material.

When recording information in a device equipped with a disc-shaped recording member formed with these films, it is possible to perform recording using a semiconductor laser λ = 8200 Å as a light source and modulation with an irradiation power of 10 mW or less. Information detection using reflected light can perform good reproduction with irradiation light of about 1 mW. Although it is difficult to analyze the composition of the recording film of the optical information recording/reproducing member, it is easy to control the composition of the starting raw material for vapor deposition, and the reflection of the manufactured optical information recording/reproducing member is difficult to analyze. It is also easy to measure characteristics such as rate and recording sensitivity. Therefore, if we control the composition of the starting material for vapor deposition, measure the characteristics of the recording film of the manufactured member, and find a starting material for vapor deposition that has good properties, we will be able to produce a good optical information recording and reproducing material. can get.

As described above, the present invention contains TeO ₂ or TeO as a main component, x mol % (0<x<50) of Tl ₂ O, and y mol % (0<x<50) of at least one of Bi, Te, and In. 0<y<30) is used as the starting material for vapor deposition, and heated in the range of 200°C to 1000°C in a vapor deposition container with a vacuum degree of 10 ^-3 mmHg ^{to 10 -6} mmHg to record light absorption on the substrate. The film is formed by vapor deposition, and the produced optical information recording/reproducing member has the following effects compared to conventional members.

(1) There is a large change in reflectance due to recording (ΔR20
%) High playback signal quality.

(2) High recording sensitivity. Semiconductor laser irradiation power
Recording is possible at less than 10mW, allowing for smaller devices.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an optical information recording/reproducing member manufactured by the method of manufacturing an optical information recording/reproducing member of the present invention, FIG. 2 is a principle diagram of a recording system of an apparatus using the same member, and FIG. FIG. 3 is a diagram showing the principle of the regeneration system, FIG. 4 is a diagram showing the principle of the manufacturing apparatus for the component, and FIGS. 5 and 6 are characteristic diagrams showing the characteristics of the component. DESCRIPTION OF SYMBOLS 1... Base material, 2... Thin film photosensitive layer, 26... Vapor deposition starting raw material, 27... Container for heating vapor deposition, 19...
Vacuum system, 20... Base material for vapor deposition, 21... Light absorbing recording film.

Claims (1)

[Claims] 1. As a starting material for vapor deposition (A _100-x Tl ₂ O _x ) _100-y M _y [where A is TeO ₂ or TeO x: mol% 0<x<50 M is Bi, Te, In At least one single material y: mol% 0 < y < 30] is heated in a vapor deposition container with a vacuum degree of 10 ^-3 mmHg to ^{10 -6} mmHg in a range of 200°C to 1000°C and deposited on a substrate. 1. A method of manufacturing an optical information recording/reproducing member, comprising forming a light-absorbing recording film by vapor deposition. 2 Adding 20% of elemental Te to a solid solution of oxides TeO ₂ and Tl ₂ O
2. The method for producing an optical information recording/reproducing member according to claim 1, wherein the starting material for vapor deposition is a mol % added material. 3. The method for producing an optical information recording/reproducing member according to claim 1, wherein a solid solution of oxides TeO ₂ and Tl ₂ O to which 10 mol % of elemental Bi is added is used as a starting material for vapor deposition. 4. The method for producing an optical information recording/reproducing member according to claim 1, wherein a solid solution of oxides TeO ₂ and Tl ₂ O to which 20 mol % of elemental In is added is used as a starting material for vapor deposition.