JPH0414643A - 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 and suppressing the difference in moisture absorption and the difference in coefft. of thermal expansion between the front and rear of a resin substrate. CONSTITUTION:A SiAlON layer (dielectric layer 4), a TbFeCo layer (recording layer 5) a SiAlON layer (protective layer 6), and an Al film (reflecting layer 7) are successively formed on the substrate for the optical information recording medium consisting of a polycarbonate resin. An over coating layer 8 is then formed on the optical information recording layer by a spin coating method using a UV curing resin. An isobutanol soln. of gamma-glycido xypropyl trimethoxy- silane is applied by the spin coater on the rear side of the surface formed with the optical information recording layer and is dried by heating to form an underlying layer 12. The substrate is introduced into the vacuum chamber of a sputtering device and thereafter, the chamber is evacuated and gaseous Ar is introduced therein. The transparent thin film layer 3 consisting of SiO2 is then formed by plasma sputtering.

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.

By the way, in a single-plate optical information recording medium using a transparent resin (plastic) for the substrate, there is a problem that the shape changes due to the inherent temperature and humidity of 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 into a concave shape. Next, in terms of 4L degree change, when the environment of an optical information recording medium is changed from low temperature to high temperature under a constant humidity condition, bias depending on the surface (so-called bimetal effect) occurs due to the difference in thermal expansion coefficient, and the 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 thermal expansion coefficients, but this point has not been taken into account in the prior art.

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 between the front and back surfaces in terms of expansion and contraction of the substrate due to changes in the environment (changes in humidity or temperature). 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] The present invention aims to solve the problem of warping caused by a single-layer structure and to provide an optical information recording medium having a single-layer structure that has stable characteristics with little tracking error. purpose.

Further, the present invention aims to provide an optical information recording medium that is small in mechanical change due to environmental changes such as temperature and humidity during actual use in a single-plate optical information recording layer using a transparent resin substrate. purpose.

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. An object of the present invention is 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 silane coupling agent or a titanium coupling agent. shall be.

(Transparent substrate) Materials for the transparent substrate include, for example, 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 multi-layered.

Examples of materials for the intermediate layer and the protective layer include SiO2
, SiN, , 5iAflON, 5iAJ2N, etc. can be used, and the thickness is generally 200 to 200 mm.
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(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 TbFeCo.

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 layers.

In the optical information recording medium of the present invention, at least a dielectric layer, a recording layer, and a protective layer are laminated in this order on one surface of the transparent substrate, and the outer surface of the protective layer is made of aluminum, which is commonly used. A reflective layer made of 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 silane coupling agent or a titanium coupling agent is used as a material for the underlayer. The base layer made of a silane coupling agent or a titanium coupling agent increases the adhesion between the substrate and the transparent thin film layer made of an inorganic material, prevents warping of the optical information recording medium, and contributes to improving various properties.

The silane coupling agent is preferably represented by the following formula.

XnS i Y4-n (where n = 1 to 3) where X is a vinyl group, methacryloxy group, epoxy group,
It is a hydrocarbon having 1 to 10 carbon atoms having an amino group or an isocyanate group, and Y is a hydrocarbon having 1 to 10 carbon atoms having an alkoxy group, an alkoxyalkoxy group, an acetoxy group, or a hydroxyl group.

More specifically, for example, γ-aminopropyltriethoxysilane, γ-isocyanatepropyltrimethoxysilane, γ-incyanatepropyltriethoxysilane, γ-isocyanatepropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxy Silane, γ
- Glycidoxypropyltriethoxysilane, glycitoxypropyltripropoxysilane, glycitoxypropylmethyldimethoxysilane, glycidoxybrobilmethyldiethoxysilane, glycidoxypropylethyldimethoxysilane, glycidoxypropylethyldimethoxysilane Toxysilane, glycidoxypropylbutyldimethoxysilane, glycitoxypropylbutyljethoxysilane, 2
- (2,3-epoxycyclohexyl)ethyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-anilinopropyltrimethoxysilane, N-phenylaminomethyltrimethoxysilane, N-(triethoxypropyl)urea, aminomethyltriethoxysilane, N-(β-aminoethyl)aminomethyltrimethoxysilane, aminomethyljet Examples include toxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris(β-methoxyethoxy)silaneethoxy, vinylacetoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and the like.

In addition, examples of titanium coupling agents include isopropyltriisostearoyltitanate, isopropyltrioctanoyltitanate, isopropylisostearoyldiacryltitanate, isopropyltri(N-aminonythylaminomethyl)titanate, and tetraoctylbis(
Examples include ditridecyl phosphite) titanate, isopropyl tricumylphenyl titanate, tetraisopropyl his(dioctyl phosphite) titanate, triethanolamine titanate, titanium acetylacetonate, titanium acetylacetonate, titanium ethyl acetoacetate, and titanium lactate. In addition, aluminum-based coupling agents,
A zirconium coupling agent or the like may also be used.

Note that the thickness of this underlayer is preferably 100 Å or less, more preferably several tens of Å or less.

If the number exceeds 100, for example, if polycarbonate is used as the substrate, there is a risk of wall damage.

The lower limit of the thickness of the base layer is preferably 1 to 2 molecular layers. If the thickness is less than one molecular layer, it becomes difficult to form the base layer.

(Transparent Thin Film Layer) As the inorganic material forming the transparent thin film layer, any inorganic material can be used, or one having excellent heat resistance and moisture resistance is 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, and cadmium oxide. Among these, at least Ifi 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 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)< so that reflection at the interface between the transparent thin film layer and the transparent substrate is minimized. 2
．． A range of 2 is preferable, but as the refractive index decreases, 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 thin film layer is preferably 600 to 3,500, more preferably 1,000 to 3,000.

Further, when forming a multilayer structure and forming a layer having conductivity, the thickness of this layer is preferably 50 to 1000 layers.

(Electron beam irradiation) Either the transparent substrate and the transparent thin film layer are strongly bonded by a base layer, or if the base layer and transparent thin film layer are formed on the transparent substrate and then irradiated with an electron beam, the synthetic resin forming the substrate will be removed. This is preferable because a chemical bond is formed between the base layer and the coupling agent of the underlayer, and the two are strongly bonded. In this case, as the synthetic resin forming the substrate, a substrate mainly composed of a polymer having a carbonyl bond (>C=O) is particularly effective. Further, since the electron beam is irradiated after the base layer and the transparent i-film layer are sequentially formed, it is possible to simultaneously form a stronger bond between the transparent thin film layer and the base layer.

According to the electron beam irradiation method, ■ Since each electron has energy, the amount of energy can be easily manipulated by manipulating the acceleration π pressure. ■ Because the high energy is integrated, It is easy to reach the reaction area between the resin part and the base layer, so it can be done in a short time.
A chemical bond is certainly formed between the two.

In addition, the dose rate of electron beam irradiation is 01 to 10 M r
ad/s is preferred, 1 to 3 M r a d
/S is more preferred. If it is less than 0.1 Mrad/s, it is due to the effect of electron beam irradiation, and if it exceeds 10 Mrad/s, it may affect the characteristics of the optical information recording medium.

In addition, when the base is made of polycarbonate, 10M
A dose below rad is preferred.

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

■Formation of base layer Apply a 0.1 to 5% by weight alcoholic solution of a coupling agent to the substrate surface opposite to the surface on which the optical information recording layer is formed using a spin coater, and air dry at room temperature for about 1 to 2 hours. or dry at 90°C for about 1 to 5 minutes.

■ Formation of an inorganic transparent thin film A transparent thin film layer made of an inorganic material can be formed by, for example, vapor deposition, ion blasting, sputtering, plasma polymerization,
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 code] Next, the present invention will be explained in detail.

(Example 1-1) An example of a schematic cross-sectional view of an optical information recording medium according to the present invention is shown below.
M1 is shown in Figure (a).

341 In Figure (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 coupling agent, 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 a dielectric layer and a protective layer, respectively, 5 is a magneto-optical recording layer, 7 is a reflective layer, and 8 is an overcoat layer such as an ultraviolet curing resin.

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) on soil under argon atmosphere 7
．． Vacuum evaporated at 0xlO-3 torr, S i Afl
The ON layer (dielectric layer 4) is made of 1TbFeCo with a thickness of 1000 mm.
The layer (recording layer 5) is 300 mm thick. The C55iA42ON layer (protective layer 6) is 300 mm thick. The C5A1 film (reflective layer 7) is 100 mm thick.
An optical information recording layer was formed by forming a film to a thickness of 1T.

Next, ultraviolet curable resin (5D-
301) using the spin code method (3000 rpm x 12 seconds)
After coating, the coating was cured by irradiating 5 joules of ultraviolet light to form an overcoat layer with a thickness of 12 μm on the optical information recording layer.

■ Formation of base layer On the back side of the surface on which the optical information recording layer is formed, apply an inbutanol solution of γ-glycytoxyprobyltrimethoxysilane (
1% by weight) was applied using a spin coater and dried by heating with hot air at 90° C. for 5 minutes to form the base layer 2.

In this example, the thickness of the base layer 2 was 30 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 lXl0-'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 1-2) In this example, An2o3 was used as the transparent thin film layer 3.

A sample was produced in the same manner as in Example 1-1 except for the above.

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

(Example 1-3) In this example, ZrO2 was used as the transparent thin film layer 3.

A sample was produced in the same manner as in Example 1-1 except for the above.

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

(Example 1-4) 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 prepared by a sputtering method by placing a titanium oxide chip on a silicon oxide turcerate 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 1-1.

ESCA analysis of this transparent thin film layer revealed that the composition of the transparent thin film layer was approximately Si:Ti:O=2:1:6 (original
It turned out to be (Chihiro).

(Comparative Example 1-1) In this example, a single-plate optical information recording medium was produced in the same manner as in (2) described in Example 1-1, without forming either a transparent thin film layer or an underlayer.

(Comparative Example 1-2) In this example, a transparent thin film layer was formed without interposing an underlying layer.

A single-plate optical recording medium was produced in the same manner as in Example 1-1 except for this boiled shell.

A test against changes in temperature and humidity was conducted using the sample prepared as described above.

[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 performed by lowering the humidity to 45% RH for 30 minutes and then maintaining the humidity.

FIG. 2(a) shows the change in the amount of warpage of the carp and carp samples.

[Temperature change test] 65°C, 45% for 30 minutes from 25°C, 45% RH
The temperature was raised to RH, maintained at that temperature for 20 hours, and then lowered again to the original temperature of 25° C. and 45% RH over 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 (+).
JIL rank 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 the sysolver oxide 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 via a silyl peroxide compound as in this example, the shape change due to environmental changes of a single-plate optical information recording medium can be greatly reduced. It turns out that it can be suppressed.

[Signal characteristics] Six samples were subjected to an environmental acceleration test at 80°C and 9%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 by forming via an underlayer than by providing directly on the back surface of the substrate (Comparative Example 1-2).

(Margin below) Table 1 *The initial value of C/N was set to 0.

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

(Example 2-1) 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.

■ Formation of optical information recording layer Substrate for optical information recording medium made of polycarbonate resin (
130φ, thickness 1.2 mm), a 1TbFeC Si AuoN layer (dielectric layer 4) was formed to a thickness of 1000 mm in the same manner as in Example 1-1.

The layer (recording layer 5) is 300mm thick C1S i AloN layer (
Protective layer 6) 300mm thick C1A℃ film (reflective layer 7) 10mm
An optical information recording layer was formed by forming a film to a thickness of 1T.

Next, an overcoat layer 8 having a thickness of 12 μm was formed on the optical information recording layer by the spin code method in the same manner as in Example 1-1 using an ultraviolet curable resin.

■ Formation of base layer On the back side of the surface on which the optical information recording layer is formed, apply an isobutanol solution of γ-glycytoxypropyltrimethoxysilane (
1% by weight) was applied using a spin coater and dried by heating with hot air at 90° C. for 5 minutes to form the base layer 2.

The thickness of this base layer was 40 people.

■Formation of the first transparent thin film layer 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 to form a transparent thin film N1 layer 3 made of 5i02. The number of transparent thin film first layer 3 was 2,500.

(2) Formation of the first 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 thin film formed consists of a mixture of tin oxide and indium oxide;
It was a transparent thin film with 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.
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(Example 2-2) Af1203 was used as the first layer 3 of the transparent thin film.

A sample was produced in the same manner as in Example 2-1 except for the above.

The total thickness of the transparent thin film first layer 3 and second layer 9 is 3000.
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(Example 2-3) ZrOx was used as the transparent thin film first layer 3.

A sample was produced in the same manner as in Example 2-1 except for the above. The total thickness of the first layer and the second layer was 3000 people.

(Example 2-4) 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 2-1.

ESCA analysis of the transparent thin film first layer 3 revealed that its composition was approximately Si:Ti:O=2:f:6 (atomic ratio).

(Comparative Example 2) In this example, the first and second transparent thin film layers were formed without intervening an underlying layer.

Except for the fishing gear, an optical information recording medium with a single-plate specification was produced in the same manner as in Example 2-1.

Using the above sample, a test for changes in temperature and humidity was conducted in the same manner as in Example 1-1.

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 1-1.

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 via a coupling agent 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 using a coupling agent show a large change. From these facts, when a transparent thin film made of an inorganic material is formed via a coupling agent as in this example, the shape change due to environmental changes of a single-plate optical information recording medium can be greatly suppressed. It turns out that it can be suppressed.

In addition, for the five samples, 80°C, 90%RHx
Table 2 shows the results of an environmental acceleration test of 500 hours and examination of changes in signal characteristics.

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

Table 2 (Example 2-5) In this example, 3000 people formed only 5i02 (transparent thin film first layer) without providing the inorganic transparent thin film second layer.

Except for this fish implement, an optical information recording medium having a single-plate specification was produced in the same manner as in Example 2-11.

The six samples of Examples 2-1 to 2-5 and Comparative Example 1-1 were used in a practical environment for three months, during which they were removed from the cartridge every 10 days, and surface deposits were inspected for scratches on optical information recording media. (R3-3200: manufactured by Hitachi Electronics Engineering).

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 transparent i-film having conductivity on the surface.

(Example 3-1) An optical information recording medium having a structure similar to that of Example 1-1, that is, a transparent thin film layer having a single layer structure, was created as follows.

■ Formation of optical information recording layer Substrate for optical information recording medium made of polycarbonate resin (
130φ, thickness 1.2 mm), a S i Aj2ON layer (dielectric layer) was formed in the same manner as in Example 1-1.
with a thickness of 100OA, and a TbFeCo layer (recording layer) with a thickness of 30OA.
A thickness, 300 S i Aj2ON layers (protective layer),
Aj2 film (reflection layer) was sequentially deposited by 1000 people to form an optical information recording layer.

Next, an overcoat layer having a thickness of 12 μm was formed on the optical information recording layer using an ultraviolet curable resin by the spin coding method in the same manner as in Example 1-1.

■ Formation of base layer On the back side of the surface on which the optical information recording layer is formed, apply an inbutanol solution of γ-glycidoxypropyltrimethoxysilane (
1% by weight) was applied using a spin coater and dried by heating with hot air at 90° C. for 5 minutes to form a base layer.

The thickness of this base layer was 80 people.

(2) Formation of Inorganic Transparent Thin Film Layer After forming the base layer, the substrate was introduced into a vacuum chamber of a sputtering device, which was then evacuated to lXl0-'torr. Then,
Ar gas was introduced at 1xlO-2 torr to form a transparent thin film layer made of Sin. MpJ of transparent thin film layer is 30
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(2) Irradiation of electron beams After forming the inorganic transparent thin film layer, the entire surface of the layer was irradiated with electron beams. The electron beam had a dose rate of 1.6 Mrad/S and a dose of 8. Irradiation was performed at OMrad in an argon gas atmosphere.

(Example 3-2) In this example, AizO3 was used as the transparent thin film layer.

A sample was prepared in the same manner as in Example 3-1 except for this point.

The thickness of the transparent thin film layer was 3000.

(Example 3-3) In this example, ZrO2 was used as the transparent thin film layer.

A sample was prepared in the same manner as in Example 3-1 except for this point.

The thickness of the transparent thin film layer was 3000.

(Example 3-4) In this example, a sample was created using a composite film of titanium oxide and silicon oxide as a transparent thin film layer. The manufacturing method was a sputtering method, in which a titanium oxide chip was placed on a silicon oxide turcerate and RF sputtering was performed. The thickness of the transparent thin film layer was 3000.

Conditions such as gas pressure were the same as in Example 3-1.

ESCA analysis of this transparent thin film layer revealed that its composition was approximately St:Ti:O=2:1:6 (atomic ratio).

Figure 5 (a) shows the change in the amount of warpage of the board in the humidity change test.
).

Figure 5 (b) shows the change in the amount of warpage of the board in the temperature change test.
).

Note that the measurement of the amount of warpage is the same as in Example 1-1.

As can be seen from FIG. 5(a) and FIG. 5(b),
In all of the samples in which a transparent thin film made of an inorganic material was provided via a coupling agent as in this example, the change in the warp angle due to environmental changes was small.

In addition, for the above four samples, 80°C, 90% R
Table 3 shows the results of a 100-time cooling/heating cycle test in which the sample was left at H for 2 hours, then the temperature was lowered over 1 hour, and left at -25°C x 40% RH for 2 hours, and changes in signal characteristics were investigated. .

Table 3 *The initial value of C/N was set to 0.

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

(Example 4-1) An optical information recording medium having a structure similar to that of Example 2-1, that is, a transparent thin film layer having a multilayer structure, was created as follows.

■ Formation of optical information recording layer Substrate for optical information recording medium made of polycarbonate resin (
130φ, thickness 1.2 mm), a S i Aj2ON layer (current reading layer) with a thickness of 100 OA and TbFeC in the same manner as in Example 1-1.

The layer (recording layer) is 30OA thick, and the Si AlloN layer (
The protective layer) is 30OA thick, and the An film (reflection layer) is 1000mm thick.
Films were sequentially formed to form an optical information recording layer.

Next, an overcoat layer having a thickness of 12 μm was formed on the optical information recording layer using an ultraviolet curable resin by the spin coding method in the same manner as in Example 1-1.

■ Formation of base layer On the back side of the surface on which the optical information recording layer is formed, apply an isoptanol solution of γ-glycidoxypropyltrimethoxysilane (
1% by weight) was applied using a spin coater and dried by heating with hot air at 90° C. for 5 minutes to form a base layer.

The thickness of this base layer was 20 people.

(2) Formation of first layer of inorganic transparent thin film After forming the base layer, the substrate was introduced into a vacuum chamber of a sputtering device, and then evacuated to lXl0-'torr.

Then, Ar gas was introduced at 1xlO-2torr, and 5i
A film consisting of 02 was formed.

(2) Formation of second inorganic transparent thin film layer After forming the first inorganic transparent thin film layer, a transparent conductive film was formed by reactive DC sputtering in an oxygen atmosphere using a tin-indium alloy target.

The total thickness of the first and second layers was 3000.

(2) Irradiation of electron beams After forming the second inorganic transparent thin film layer, the entire surface of the second layer was irradiated with electron beams. The electron beam is 1.6 M r a d /
Irradiation was performed in an argon gas atmosphere at a dose rate of 8° OMrad.

(Example 4-2) In this example, transparent? Al2O2 was used as the first layer of the V film.

A sunflu was prepared in the same manner as in Example 4-1 except for this point.

The total thickness of the first transparent thin film layer and the second transparent thin film layer is 300.
There were 0 people.

(Example 4-3) Do not use ZrO2 as the first transparent thin film layer.

A sample was prepared in the same manner as in Example 4-1 except for this point.

Transparent thin film first layer and transparent thin film! The total thickness of the second layer is 3
There were 000 people.

(Example 4-4) In this example, a sample was created using a composite film of titanium oxide and silicon oxide as the first transparent thin film layer. 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 transparent thin film layer and the second transparent thin film layer is 300.
There were 0 people.

Conditions such as gas pressure were the same as in Example 4-1.

According to ESCA analysis of this film, its composition is approximately Si
:Ti:O=2:1:6 (atomic ratio).

Using the above sample, a test for changes in temperature and humidity was conducted in the same manner as in Example 1-1.

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

Figure 6 (a) shows the change in the amount of warpage of the board in the humidity change test.
).

Figure 6 (b) shows the change in the amount of warpage of the board in the temperature change test.
).

Note that the measurement of the amount of warpage is the same as in Example 1-1.

As can be seen from FIGS. 6(a) and 6(b),
In all of the samples in which a transparent thin film made of an inorganic material was provided via a coupling agent as in this example, the change in the warp angle with respect to environmental changes was small.

The above four samples were left at 80°C and 9%RH for 2 hours, then the temperature was lowered over 1 hour, and -
Table 4 shows the results of a 100-time cooling/heating cycle test in which the sample was left at 25° C. and 40% RH for 2 hours, and changes in signal characteristics were investigated.

Table 4 *B, E, and R assume the initial value to be 1, and indicate how many times it has increased.

(Example 4-5) In this example, 3000 people formed only 5i02 without providing the second inorganic transparent thin film layer. That is, in this example, the inorganic transparent thin film layer had a single layer structure.

Except for this fish implement, an optical information recording medium having a single-plate specification was produced in the same manner as in Example 4-1.

Examples 4-1 to 4-5 and comparative examples! The six samples of -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 measured using a scratch inspection device for optical information recording media (R3-3200: manufactured by Hitachi Electronics Engineering). did.

The results are shown in FIG. However, what is observed is adhered foreign matter of 10 μm or more, and the measurement results indicate how many times the initial value has increased.

This result shows the superiority of imparting conductivity to the surface.

[Effects of the Invention] In the optical information recording medium of the present invention, since the transparent thin film is formed with very good adhesion through the base layer, the above-mentioned difference in moisture absorption between the front and back sides of the resin substrate and the coefficient of thermal expansion can be 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.

In addition, 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, which significantly improves the deterioration of signal recording and reproducing characteristics caused by environmental tests. .

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 and Comparative Examples. FIG. 3 is a graph showing the results of temperature and humidity change tests in other examples and comparative examples. FIG. 4 is a graph showing the effect of using multiple transparent thin film layers. FIG. 5 is a graph showing the results of temperature and humidity change tests in other Examples and Comparative Examples. FIG. 6 is a graph showing the results of temperature and humidity change tests in other Examples and Comparative Examples. FIG. 7 is a graph showing the effect of using multiple transparent thin film layers. (Explanation of symbols) 1... Transparent resin substrate, 2... Base layer, 3... Transparent thin film layer, 4... Flexible layer, 5... Magneto-optical recording layer, 6
...Protective layer, 7...Reflection layer, 8...Overcoat layer. Patent applicant: Sekisui Chemical Co., Ltd. Representative Hiroshi 1) Kaoru Diagram (a) Diagram (b) Diagram (0)

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 side of a transparent substrate for an optical information recording medium made of synthetic resin, and a silane coupling agent is formed on the other side. Alternatively, an optical information recording medium characterized in that a transparent thin film layer made of an inorganic material is formed with a base layer made of a titanium coupling agent interposed therebetween.