JPH0414646A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To drastically suppress mechanical deformation by forming a transparent thin film via an underlying layer with an extremely high adhesive property, thereby suppressing the difference in moisture absorption and the difference in coefft. of thermal expansion between the front and rear of a resin substrate. CONSTITUTION:The optical information recording layer having at least a dielectric layer 4, a recording layer 5 and a protective layer 6 is formed on one surface of a transparent substrate 1 for the optical information recording medium consisting of a synthetic resin. The transparent thin film 3 layer consisting of an inorg. material is formed via the underlying layer 2 consisting of a plasma-polymerized film of a silane compd. on the substrate 1 surface of the other side. Since the thin film 3 is formable with the good adhesive property via the underlying layer 2, the difference in the moisture absorption and the difference in the coefft. of thermal expansion between the front and rear of the substrate 1 is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an optical information recording medium, and more particularly to an optical information recording medium that solves the problem of warping that occurs in optical information recording media.

[Prior Art] Conventionally, a technique described in Japanese Patent Application Laid-Open No. 1-271944 is known as a technique that attempts to correct warpage that occurs in an optical information recording medium. This technology is a magneto-optical recording medium in which an optical information recording layer having an intermediate layer-recording layer-protective layer structure is formed on one side of a transparent substrate such as polycarbonate. A photocurable resin layer having a volumetric shrinkage rate of 15% is provided with a thickness of 2 μm, and then a photocurable resin layer with a smaller volumetric shrinkage rate is provided on the back side of the transparent substrate with a thickness of 2 μm.
It should be thick. This technique attempts to correct the warpage of a medium by utilizing the difference in volume shrinkage between the front and back surfaces of a transparent substrate.

Incidentally, in a single-plate optical information recording medium using a transparent resin (plastic) for the substrate, there is a problem in that the shape changes due to temperature and humidity, which is inherent in the resin. That is, in a single-plate optical information recording medium in which a recording layer and a protective layer are provided only on one side of the optical information recording medium, the side on the optical information recording layer side and the side opposite to the optical information recording layer are This results in a different surface state.

First, in terms of moisture absorption, when an optical information recording medium is changed from a low humidity environment to a high temperature while the temperature is constant; due to the hygroscopicity of the substrate, unevenness occurs depending on the surface, and the surface on the optical information recording layer side Changes to a concave shape. Next, in terms of temperature changes, when the environment of an optical information recording medium is changed from low to high temperature with constant humidity, unevenness depending on the surface (so-called bimetal effect) occurs due to the difference in thermal expansion coefficient, and optical information The surface on the recording layer side changes to a concave shape.

Now, the content of the prior art does not mention these basic facts. What is considered in the prior literature is only how to correct the initial value of warpage that occurs during the manufacturing of optical information recording media. Even if the initial value is corrected by the conventional technology described above, in terms of moisture absorption, just having an organic thin film (photocured resin layer) of a few micrometers will only slow down the rate of moisture permeation, and the organic thin film will not absorb moisture. When the light passes through the light, bias due to hygroscopicity occurs, causing the optical information recording medium to warp. In terms of temperature, it is necessary to eliminate bias caused by differences in coefficients of thermal expansion, but the prior art does not take this point into consideration.

In this way, a single-plate optical information recording medium in which a recording layer, a protective layer, etc. are formed on only one side of a transparent resin substrate,
Deformation occurs because there is a difference in the expansion and contraction of the substrate in response to changes in the environment (changes in humidity or temperature) between the front and back sides. This deformation usually results in surface warping of the optical information recording medium. In actual use, such problems have a negative impact on the mechanical properties of the optical information recording medium, as well as on the recording and reproduction signal characteristics (for example, they cause frequent tracking errors), so some method must be taken to prevent them. There is a need.

[Problems to be Solved by the Invention] An object of the present invention is to provide an optical information recording medium having a single-layer structure that solves the problem of warpage caused by a single-layer structure and has stable characteristics without tracking errors. With the goal.

Another object of the present invention is to provide a single-plate optical information recording medium using a transparent resin substrate, which exhibits extremely small mechanical changes due to environmental changes such as temperature and humidity during actual use.

Furthermore, in consideration of the actual usage environment, the present invention provides conductivity to the outermost surface of the surface where light enters, thereby minimizing the adhesion of dust due to static electricity on the synthetic resin under the actual usage environment. It is an object of the present invention to provide an optical information recording medium in which deterioration in signal recording and reproducing ability is improved.

[Means for Solving the Problems] An optical information recording medium for solving the above problems includes a dielectric layer, a recording layer, and a protective layer on one surface of a transparent substrate for optical information recording media made of synthetic resin. A transparent thin film layer made of an inorganic material is formed on the other side of the substrate via a base layer made of a plasma polymerized film of a silane compound.

(i! Bright substrate) Examples of the material for the transparent substrate include polycarbonate,
Any conventionally used transparent synthetic resin substrate for optical information recording media, such as acrylic or epoxy, may be used.

(Dielectric Layer and Protective Layer) The protective layer is formed outside the recording layer mainly for the purpose of preventing characteristic deterioration due to oxidation of the recording layer. Further, the dielectric layer is formed inside the recording layer for the purpose of improving reproduction characteristics by increasing the Kerr effect using multiple reflections of light. The dielectric layer may be multilayered.

As the material for the intermediate layer and the protective layer, for example, 5i02
, SiN, 5iAJ2ON, 5iAJ2N, etc. can all be used, and the thickness is generally 200~200mm.
There are 0 people.

(Recording layer) The recording layer is not particularly limited as long as it has an information recording function of the optical information recording medium. Examples of the material for the recording layer include TbFe and TbFeC.

GdFe, GdTbFe, TbCo, DyFe.

Any material such as NdDyFeCo can be used.

In addition to the above-mentioned magneto-optical recording layer, phase change type or organic dye type recording layers can also be used.

The thickness of the recording layer is generally between 200 and 1000 mm.

In the optical information recording medium of the present invention, at least an electroconductive layer, a recording layer, and a protective layer are laminated in this order on one surface of the transparent substrate. A reflective layer made of aluminum or an overcoat layer made of ultraviolet curing resin may be laminated.

(Underlayer) In the present invention, a transparent thin film layer made of an inorganic material is formed on the surface of the substrate opposite to the side on which the optical information recording layer is formed, with the underlayer interposed therebetween.

In the present invention, a plasma polymerized film of a silane compound is used as the material 1 for the base layer. The base layer made of a silane compound plasma polymerized film is thought to have the function of a coupling agent, and the base layer made of a substrate and an inorganic material is
It improves adhesion with the Meibokueki layer, prevents warping of the optical information recording medium, and contributes to improving various properties.

The silane compound is preferably one represented by the following two formulas.

CH2-CI(!l l (Fj I),, (OR”
)s-n -...■ (Tatashi, n=o~3) (However, m=o~3) In the formula, R1 is a hydrocarbon group having 1 to 6 carbon atoms, R2 is an alkoxy group, alkoxy It is an alkoxy group or an acetoxy group.

Specifically, for example, triethoxy(vinyl)silane,
Trimethoxy(vinyl)silane, methoxy(dimethyl)
Vinylsilane, ethoxy(dimethyl)vinylsilane, dimethoxy(methyl)vinylsilane, jetoxy(methyl)vinylsilane, dimethoxy(acetoxy)vinylsilane, tributoxy(vinyl)silane, and the like.

In the formula 0, R3 is a methyl group, R4 is a -(CH3)1- group (
1=1-5), R'5 is a hydrocarbon group having 1 to 6 carbon atoms, R
5 is an alkoxy group, an alkoxyalkoxy group, or an acetoxy group.

More specifically, examples thereof include γ-methacryloxypropyl(trimethoxy)silane, γ-methacryloxypropyl(dimethoxy)methylsilane, γ-methacryloxypropyl(triethoxy)silane, γ-methacryloxy(jethoxy)methylsilane, and the like.

A plasma polymerized film has excellent adhesion to a substrate, but the adhesion to the substrate can be further improved by heating the substrate. Furthermore, by plasma-treating the plasma-polymerized film of the silane compound with oxygen gas, the surface selectively becomes closer to 5 in 2 , so that the adhesion to the next laminated transparent thin film is further improved.

If the substrate is heated at a temperature several tens of degrees lower than the Tg of the substrate,
No deterioration of board performance occurs.

(Transparent Thin Film Layer) Any inorganic material can be used to form the transparent thin film layer, but those with excellent heat resistance and moisture resistance are preferable, such as zirconium oxide, calcium oxide, tantalum oxide, Examples include indium oxide, tungsten oxide, cadmium oxide, antimony oxide, niobium oxide, cesium oxide, yttrium oxide, aluminum oxide, and silicon oxide. At least one of these may be used, or two or more may be used in combination, or in combination with an inorganic material forming a protective layer.

The transparent thin film layer may not have a single layer structure but may have a multilayer structure of two or more layers.

In the case of a multilayer structure, the outer layer (particularly the outermost layer) is preferably made of a conductive material. Examples of such materials include indium oxide, tin oxide, cadmium oxide, and the like. At least one of these may be used, or a plurality of them may be used.

The transparent thin film layer can be formed to have any thickness. However, it is preferable that the thickness be such that it satisfies the phase and amplitude conditions for preventing a decrease in the amount of transmitted light during recording and reproduction and for preventing reflection of incident light on the transparent resin substrate.

In addition, in order to prevent loss of the amount of light incident on the transparent substrate, the refractive index (n) of the transparent thin film layer is set to 1.3<(n )<
A range of 2.2 is preferable, but as the refractive index decreases iJX, the film quality deteriorates and the moisture resistance decreases.

Furthermore, if the coefficient of thermal expansion of the transparent thin film layer is different from that of the optical information recording layer, the recording medium will be deformed by heat, so it is preferable that the coefficients of thermal expansion of both layers are approximately the same.

Therefore, the thickness of the transparent 'fit film is preferably 600 to 3,500, more preferably 1,000 to 3,000. Further, when a multilayer structure is formed and a conductive layer is formed, the thickness of this layer is preferably 50 to 1000 layers.

(Example of manufacturing method) The optical information recording medium according to the present invention may be manufactured, for example, as follows.

(2) Formation of Base Layer The plasma polymerization apparatus used may be a known one, and any of the apparatuses such as a Pelger type internal electrode type, a Pelger type external electrode type, and a tube type electrodeless type can be used. The plasma polymerization conditions depend on the type and size of the apparatus used, the type of polymer used, the flow rate of the monomer, the pressure of the carrier gas, the discharge power, etc. As the carrier gas, common gases such as oxygen, argon, nitrogen, etc. can be used. In addition to high-frequency discharge, plasma generation sources include
Microwave discharge, direct current discharge, alternating current discharge, etc. can all be used.

Discharge power is 10~100W, gas pressure 0.5~2,
Otorr, silane compound child flow rate 0.1-20
cc/min Furthermore, when using a gas such as oxygen, argon, or nitrogen, the gas pressure is preferably 0.1 to 1.0 torr. The polymerization time may be about 30 seconds to 5 minutes. The substrate is preferably heated to 7 g or less of the substrate used, for example, about 70 to 90° C. for a polycarbonate substrate.

When the plasma polymerized film is plasma treated with oxygen gas, its adhesion with the transparent thin film layer is further improved, but this plasma treatment is preferably carried out in an oxygen gas atmosphere after exhausting 1,000 ml of gas in the plasma polymerization equipment. . Processing conditions depend on the size, type, discharge power, etc. of the equipment used, but usually discharge power is 10 to 100 W, gas pressure is 0. 5-2.
0 torr gas flow 4f (preferably 50 to 200 cc/min) and processing time may be about 30 seconds to 1 minute.

■Formation of an inorganic transparent thin film The formation of a transparent thin film layer made of an inorganic material can be performed, for example, by vapor deposition, ion blasting, sputtering, plasma polymerization, etc.
Any manufacturing method that can uniformly form a film on the substrate, such as plasma CVD, may be used.

Note that the optical information recording layer and the transparent thin film layer made of an inorganic material may be deposited in any order.

[Example] Next, the present invention will be explained in detail.

(Example 1) An example of a schematic cross-sectional view of an optical information recording medium according to the present invention is shown in FIG. 1(a).

In FIG. 1(a), 1 is a transparent resin substrate, and in the figure, guide grooves are formed on the upper surface. 2 is a base layer made of a plasma polymerized film of a silane compound, and 3 is a transparent thin film layer made of an inorganic material, which has a single layer structure in this example. 4 and 6 are respectively an 8 electric layer and a protective layer, 5 is a magneto-optical recording layer, and 7 is
8 is a reflective layer, and 8 is an overcoat layer made of ultraviolet curing resin or the like.

Of course, 4 to 8 here are layers having the characteristics of a recording layer and a protective layer, and can have an optimal configuration for each recording method. Therefore, there is no problem in changing the configuration and number of the 4 to 8 films.

An optical information recording medium having the structure shown in FIG. 1(a) was produced by the following procedure.

■ Formation of optical information recording layer Substrate for optical information recording medium made of polycarbonate resin (
130φ, thickness 1.2mm) under an argon atmosphere,
Vacuum evaporated at 7.0X10-3 torr, S i Aj
JON layer (electroconductor layer 4) with 100° input pressure, TbFeC
o layer (recording layer 5) with a thickness of 300 layers C15iAJ: 108 layers (protective layer 6) with a thickness of 300 layers C1Al1 film (reflection layer 7) with a thickness of 1000 layers was sequentially formed to form an optical information recording layer. .

Next, ultraviolet curing resin (5D-
301) was applied using a spin code method (300 rpm x 12 seconds), and then cured by irradiating 5 joules of ultraviolet light.
A 12 μm thick overcoat layer was formed on the optical information recording layer.

(2) Formation of Underlayer A plasma polymerized film was formed on the back side of the surface on which the optical information recording layer was formed under the following conditions.

Tritoxyvinylsilane gas? Rough amount - 1cc/m1nA
r Gas flow rate - 100 cc/min Discharge frequency - 13,56 M) 12 Gas pressure car 1.5 torr Discharge power - 100 W Discharge time - 1,0 m1n Substrate temperature - 70°C Next, the 100% gas in the reaction layer was completely removed. Thereafter, the chamber was evacuated to 10@-3 torr, and plasma treatment was performed under the following conditions.

Oxygen gas flow rate -50cc/min Discharge frequency -13,56MHz Gas pressure car 1.5torr Discharge power -100W Discharge time - 0.7m1n The film thickness was 200 people.

■Formation of an inorganic transparent thin film After forming the base layer 2, the substrate is introduced into a vacuum chamber of a sputtering device, and then evacuated to 1xlO-'torr, and then,
Ar gas was introduced at lXl0-2 torr, and a transparent thin film layer 3 of 5 in 2 was formed by plasma sputtering.

In this example, the thickness of the transparent thin film layer 3 was 3000 layers.

(Example 2) In this example, Al120s was used as the transparent thin film layer 3. A sample was produced in the same manner as in Example 1 except for this.

The thickness of the transparent thin film layer 3 was 3000.

(Example 3) In this example, ZrO2 is used as the transparent thin film layer 3. A sample was produced in the same manner as in Example 1 except for this.

The thickness of the transparent thin film layer 3 was 3000.

(Example 4) In this example, a sample was created using a composite film made of a mixture of titanium oxide and silicon oxide as the transparent thin film layer 3.

The sample was created by a sputtering method by placing a titanium oxide chip on a silicon oxide target and using RF sputtering.

The thickness of the transparent thin film layer 3 was 3000.

Conditions such as gas pressure were the same as in Example 1.

ESCA analysis of this transparent thin film layer revealed that approximately
/iiFIAt7) m composition is Si :Ti :O=2:
It was found that the atomic ratio was 1:6.

(Example 5) In this example, the plasma polymerized film of the base layer was formed without oxygen plasma treatment.

Except for this point, an optical information recording medium using a single plate was produced in the same manner as in Example 1.

(Comparative Example 1) In this example, a single-plate optical information recording medium was produced in the same manner as described in Example 1 without forming either a transparent thin film layer or a base layer.

(Comparative Example 2) In this example, a transparent thin film layer was formed without interposing an underlying layer.

Except for this point, a single-plate optical information recording medium was produced in the same manner as in Example 1.

Examples 1 to 4 of the samples created as above
A test was conducted on changes in temperature and humidity using Comparative Example 1.2.

[In the humidity change test, the sample was first left in an environment of 25°C and 45% RH for 100 hours, then the temperature remained at 25°C and the humidity increased to 90% RH within 30 minutes. Moisten,
Leave it as it is for 20 hours, then return to the original 25 hours.
The test was carried out by cooling down to 45% RH for 30 minutes and then maintaining the humidity.

The change in the amount of warpage of the sample at this time is shown in FIG. 2(a).

[Temperature change test] 65°C, 45% for 30 minutes from 25°C, 45% RH
The temperature was raised to RH, maintained as such for 20 hours, and then lowered to the original temperature of 25° C. and 45% RH for 30 minutes. Figure 2 (b) shows the change in the amount of warpage of the sample at this time.
).

The amount of warpage is expressed as the warpage angle at 60 mm from the center of the substrate, with the convex direction of the surface on which the recording layer is formed being (-) negative, and the concave direction being positive (+).
Unit: mrad).

As can be seen from the figure, in all of the samples in which a transparent thin film made of an inorganic material was provided via a plasma polymerized product of a silane compound according to this example, the change in the warp angle due to environmental changes was small. On the other hand, samples without this feature showed large changes. Based on these facts, when a transparent thin film made of an inorganic material is formed through plasma polymerization of a silane compound as in this example, it is possible to prevent the shape change of a single-plate optical information recording medium due to environmental changes. It was found that this can be significantly suppressed.

[Signal characteristics] Seven samples of Examples 1 to 5 and Comparative Example 1.2 were subjected to an environmental acceleration test at 80°C and 90% RH for 500 hours, and the C/N, B, E, R (pit error rate) ) Table 1 shows the results of investigating changes in signal characteristics.

From the results shown in Table 1, it is clear that a transparent thin film layer made of inorganic material
It can be seen that clearly better signal characteristics can be obtained when the signal is formed via an underlayer than when it is formed directly on the back surface of the substrate (Comparative Example 2).

(Margin below) Table 1 *The initial value of C/N was O.

*B, E, and R assume the initial value to be 1, and indicate how many times it has increased.

(Example 6) An example of a schematic cross-sectional view of an optical information recording medium according to this example is shown in FIG. 1(b).

The difference between the structure shown in FIG. 1(a) and the structure shown in FIG. 1(b) is that in the structure shown in FIG. 1(b), the transparent thin film layer is
It consists of layer 3 and second layer 9. That is, this example shows a case where the transparent thin film layer has a multilayer structure.

An optical information recording medium having the structure shown in FIG. 1(b) was produced by the following procedure.

(2) Formation of Underlayer On the other side of the substrate on which the optical information recording layer was formed in the same manner as in Example 1, a plasma polymerized film was formed under the following conditions.

Trimethoxyvinylsilane gas flow rate - 1cc/m1nA
r Gas flow rate - 100 cc/min Discharge frequency - 13.56 MHz Gas pressure 1.5 torr Discharge power - 100 W Discharge time - 1.0 min Substrate temperature - 70°C Next, the solute gas in the reaction layer was completely removed. Thereafter, the chamber was evacuated to 10@-3 torr and subjected to plasma treatment under the following conditions.

Oxygen gas flow rate -50cc/min Discharge frequency -13,56MHz Crush pressure -1.5 torr Discharge power -100W Discharge time - 0.7m1n The film thickness was 180 people.

■Formation of the first transparent thin film layer After forming the base layer 2, the substrate is introduced into the vacuum chamber of the sputtering device, and then the air is evacuated to lXl0-'torr, and then,
Ar gas was introduced at 1xlO-'torr to form a transparent thin film first layer 3 of 5iOz. The number of transparent thin film first layer 3 was 2,500.

(2) Formation of second transparent thin film layer After forming the first transparent thin film layer 3, reactive DC sputtering was performed in an oxygen atmosphere using a tin-indium alloy target. The formed thin film was made of a mixture of tin oxide and indium oxide, and this layer was a transparent thin film having conductivity.

The thickness of this transparent thin film second layer 9 is 500, and the total thickness of the transparent thin film first layer 3 and the transparent thin film second layer 9 is 30.
There were 00 people.

(Example 7) AJ2203 was used as the transparent thin film first layer 3.

A sample was produced in the same manner as in Example 6 except for this.

The total thickness of the transparent thin film first layer 3 and second layer 9 is 3000.
It was a person.

(Example 8) ZrO2 was used as the transparent thin film first layer 3.

Other than that, a sample was created in the same manner as in Example 66.
'The total thickness of the M1 layer and the second layer was 3000.

(Example 9) In this example, a sample was created using a composite film of titanium oxide and silicon oxide as the transparent thin film first layer 3.

The manufacturing method was a sputtering method, in which a titanium oxide chip was placed on a silicon oxide target and RF sputtering was performed.

The total thickness of the first and second transparent thin film layers was 3,000.

Conditions such as gas pressure were the same as in Example 6.

When the transparent thin film first layer 3 was analyzed by ESCA, its composition was approximately Si:Ti:O=2:16 (atomic ratio)
Met.

(Example 10) In this example, the plasma polymerized film of the base layer was formed without oxygen plasma treatment.

Except for this point, an optical information recording medium using a single plate was produced in the same manner as in Example 6.

(Comparative Example 3) In this example, the first and second transparent thin film layers were formed without intervening an underlying layer.

Except for this point, a single-plate optical information recording medium was produced in the same manner as in Example 6.

Among the above samples, Examples 6 to 9 and Comparative Examples 1.3 were used to conduct a test on changes in temperature and humidity in the same manner as in Example 1.

Figure 3 (a) shows the change in the amount of warpage of the board in the humidity change test.
).

Figure 3 (b) shows the change in the amount of warpage of the board during the temperature change test.
).

The amount of warpage was measured in the same manner as in Example 1.

As can be seen from Figure 3(a) and Figure 3(b),
In all of the samples in which a transparent thin film made of an inorganic material was provided through a plasma polymerized film of a silane compound as in this example, the change in the warp angle due to environmental changes was small. On the other hand, samples that do not have a transparent thin film made of an inorganic material or samples that have a transparent thin film made of an inorganic material without a plasma-polymerized film of a silane compound show a large change.゛From these facts, when a transparent thin film made of an inorganic material is formed via a plasma polymerized film of a silane compound as in this example, the shape of a single-plate optical information recording medium due to environmental changes can be reduced. It was found that changes could be significantly suppressed.

Six samples of Examples 6 to 10 and Comparative Example 3 were subjected to an environmental acceleration test at 80° C., 90% RH x 500 hours, and changes in signal characteristics were examined. Table 2 shows the results.

From the results shown in Table 2, it can be seen that the results are better when a brimer layer is provided on the car than when only an inorganic compound thin film layer is provided on the car.

The six samples of Examples 1 and 6 to 9 and Comparative Example 1 were used in a practical environment for 3 months, during which time they were removed from the cartridge every 10 days, and surface deposits were examined using a scratch inspection device for optical information recording media (R5- 3200: Measured by Hitachi Electronics Engineering Co., Ltd.).

The results are shown in FIG. However, the observation distance is 10 μm.
The measurement result shows how many times the initial value has increased with the above-mentioned attached foreign matter.

This result shows the superiority of providing the second layer of a transparent thin film having conductivity on the surface.

Table 2 *B, E, and R assume the initial value to be 1, and indicate how many times it has increased.

[Effects of the Invention] In the optical information recording medium of the present invention, the transparent thin film is formed with very good adhesion through the base layer, so that the above-mentioned difference in moisture absorption between the front and back sides of the resin substrate and the coefficient of thermal expansion are avoided. The difference can be suppressed. Therefore, it has become possible to significantly suppress mechanical deformation caused by these.

Further, since the transparent thin film layer is made of an inorganic material, the surface hardness is high, and one of the effects is that the scratch resistance is improved.

Furthermore, by suppressing mechanical deformation due to environmental changes, the stress applied to the interface between the transparent resin substrate and the dielectric film is reduced, and deterioration in signal recording and reproducing characteristics due to environmental tests and the like is significantly improved.

In addition, in optical information recording media that use resin substrates, static electricity can build up inside the optical information recording media due to various factors such as contact with the case during actual use, the influence of humidity, and contact between the spindle and the hub. There is a tendency for the optical head to accumulate, and as a result, dirt and dust may adhere to it, causing B, E, and R to change from day to day, and in some cases, there is a risk that the optical head may come into contact with the optical information recording medium. On the other hand, the optical information recording medium of the present invention in which the transparent thin film layer is multi-layered and the outermost surface is given conductivity can discharge the static electricity accumulated in the optical information recording medium into the atmosphere, so that the optical information recording medium can The information recording medium can be used while maintaining stable performance without worrying about the environment in which it is used or the cleaning of the surface of the medium.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing the structure of an optical information recording medium according to an embodiment. FIG. 2 is a graph showing the results of temperature and humidity change tests in Examples 1 to 4 and Comparative Example 1.2. FIG. 3 is a graph showing the results of temperature and humidity change tests in Examples 6 to 9 and Comparative Example 1.3. FIG. 4 is a graph showing the effect of binding multiple transparent thin film layers. (Explanation of symbols)...Transparent resin substrate, 2...Underlayer, 3゜9...Transparent thin film layer, 4...Reflexive layer, 5...Magneto-optical recording layer, 6... - Protective layer, 7... Reflective layer, 8... Overcoat layer.

Claims (1)

[Claims] (1) An optical information recording layer having at least a dielectric layer, a recording layer and a protective layer is formed on one surface of a transparent substrate for an optical information recording medium made of synthetic resin, and a plasma of a silane compound is formed on the other surface. An optical information recording medium characterized in that a transparent thin film layer made of an inorganic material is formed through a base layer made of a polymer film.