JPH0414642A - 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 by vacuum vapor deposition in an argon atmosphere on the substrate for the optical information recording medium consisting of a polycarbonate resin. After a UV curing resin is applied by a spin coating method thereon, the coating is irradiated with UV rays and is thereby cured to form an over coat layer on the optical information recording layer. A hexane soln. of gamma-methacryloxy propyl tris-silane is applied by the spin coater on the rear surface of the recording layer and is dried by heating to form an underlying layer 2. The substrate is introduced into the vacuum chamber of a sputtering device after the formation of the underlying layer 2 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 uses 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 the medium by utilizing the difference in volume shrinkage between the front and back surfaces of the 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 the optical information recording medium The surface on the 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 between the front and back sides in terms of expansion and contraction of the substrate due to environmental changes (4 degrees or temperature changes). This deformation results in warping of the optical information recording medium during school use. 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 to.

[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.

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 use environment, the present invention minimizes the adhesion of dust due to IF electricity to the synthetic resin under the actual use environment by imparting conductivity to the outermost surface of the surface where light enters. An object of the present invention is to provide an optical information recording medium that has improved signal recording and reproducing ability.

[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 silyl peroxide compound.

(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 multilayered.

As the material for the intermediate layer and the protective layer, for example, 5in2
．． SiN, 5iAIION, 5iADN, etc. can all be used, and the thickness is generally 200~2000mm.
It's a person.

(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 200 to 200 mm thick.

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. 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 silyl peroxide compound is used as a material for the underlayer. The base layer made of a silyl peroxide compound is thought to act as a coupling agent, increasing the adhesion between the substrate and the transparent thin film layer made of an inorganic material, and preventing warping of the optical information recording medium. , contributes to improvement of various characteristics.

The silyl peroxide compound is preferably one represented by the following formula.

Ran-n S 1 (OOR’).

(However, n = 1 to 4) In the formula, R is a hydrocarbon group having 1 to 6 carbon atoms, a vinyl group, a methacryloxy group, an epoxy group, an amino group, a mercapto group, an organic group having fluorine or chlorine, and R ' is one or more bonding groups selected from an alkyl group, an acyl group, and an arylalkyl group, and n is an integer of 1 to 4.

More specifically, for example, vinyltris(t-butylperoxy)silane, vinyltris(cumemberoxy)silane, vinyltris(acetylperoxy)silane, vinyltris(benzoylperoxy)silane, vinyltris(lauroylperoxy)silane, γ-glycidoxypropyltris(t-butylperoxy)silane, γ-glycidoxypropyltris(cumene oxygen)silane, γ-glycidoxypropyltris(acetylperoxy)silane, γ-glycidoxy Propyltris(benzoylperoxyfusilane, γ-glycidoxypropyltris(lauroylperoxy)silane, γ-
Methacryloxypropyltris(t-butylperoxy)silane, γ-methacryloxypropyltris(cumemberoxy)silane, γ-methacryloxypropyltris(acetylperoxy)silane, γ-methacryloxypropyltris(benzoylperoxy) Silane, γ
- methacryloxypropyltris(lauroylperoxy)silane and the like.

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 thick. If the thickness is less than one molecular layer, it becomes difficult to form the base layer.

(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, and cadmium oxide. 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 transparent 'fit II! The refractive index (n) of the layer is 1.3<
The range of (n)<2.2 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 a multilayer structure is formed and a conductive layer is formed, the thickness of this layer is preferably 50 to 1000 layers.

(Electron beam irradiation) The transparent substrate and the transparent thin film layer are firmly bonded by the base layer, but if the base layer and the transparent thin film layer are formed on the transparent substrate and then irradiated with an electron beam, the synthesis that forms the substrate will occur. It is preferable that a chemical bond is formed between the resin and the silyl peroxide compound of the underlayer, so that the two are strongly bonded. On this occasion,
The synthetic resin that forms the substrate is carbonyl bond (〉
A substrate based mainly on a polymer having C20) is particularly effective. Further, since the electron beam is irradiated after the base layer and the transparent thin 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, ■Energy is contained in each electron, so the amount of energy can be easily manipulated by manipulating the accelerating voltage. ■Since the high energy is integrated, the resin on the substrate surface Because it is easy to reach the reaction site between the base layer and the base layer, 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 0.1 to 10 M'r.
ad/s is preferable, and 1 to 3 Mr ad/S is more preferable. 0. If it is less than IMrad/s, the effect of electron beam irradiation is small, and if it exceeds 10 Mrad/s, the characteristics of the optical information recording medium may be affected.

In addition, when the base is made of polycarbonate, 20M
Doses below rad are preferred.

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

■Formation of the underlayer Add 1fi or more of silyl peroxide compounds to the substrate surface opposite to the surface on which the optical information recording layer is formed, such as toluene, hexane, methyl ethyl ketone, methyl isobutyl ketone, heptane, ethyl acetate, butyl acetate, or cyclohexanone. It is dissolved in a solvent such as, and applied as a 0.1 to 5% by weight solution using, for example, a spin coater, and dried in the air for about 1 to 2 hours at room temperature or for about 1 to 5 minutes at 60°C.

■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 formed in either order.

[Example] 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 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 silyl peroxide compound, and 3 is a transparent thin film layer made of an inorganic material, which has a single layer structure in this example. Reference numerals 4 and 6 designate a current visitor and a protective layer, respectively, 5 a magneto-optical recording layer, 7 a reflective layer, and 8 an overcoat layer such as an ultraviolet curing resin.

Of course, 4 to 8 here are layers in the nature of a recording layer and a protective layer, and it is up to them to take the 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 7.0xlO-'torr, S i Aj
The 2ON layer (dielectric layer 4) is made of 1TbFeC with a thickness of 1000 mm.
O layer (recording layer 5) is 300 mm thick, 1.5 iAAON layer (protective layer 6) is 300 mm thick, An 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 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.

■ Formation of base layer A hexane solution (3% by weight) of γ-methacryloxypropyltris(t-butylperoxy)silane is applied using a spin coater to the back side of the side on which the optical information recording layer is formed.
The base layer 2 was formed by heating and drying with hot air at 60° C. for 5 minutes.

In this example, the thickness of this 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 1xlO-'torr, and then,
At gas was introduced at a pressure of 1×1O”2 torr, and a transparent thin film layer 3 having a thickness 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, a sample was created in the same manner as in Example 1-1 except that AJ220s was used as the transparent thin film layer 3.

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

(Example 1-3) In this example, ZrQ2 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 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 are examples! I decided it was -1.

According to ESCA analysis of this transparent thin film layer, the composition of the transparent thin film layer is approximately Sf:Ti:O=2:1:6
(1) i child ratio).

(Comparative Example 1-1) In this example, neither a transparent thin film layer nor an underlayer was formed, and a single-plate optical information recording medium was produced in the same manner as in (2) described in Example 1-1.

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

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

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.

The change in the amount of warpage of the sample at this point 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 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 (+).
unit 11 rad).

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 silyl peroxide 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 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 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 W# 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 Si AllON layer (iron layer 4) was formed in the same manner as in Example 1-1.
to 100OA/H, TbFeC.

The layer (recording layer 5) is 300 layers thick, 1.5iAlON layer (protective layer 6) is 300 layers thick, 1,8β11! (Reflection layer 7) 1
The optical information recording layer was formed by sequentially forming a film to a thickness of 1,000 mm.

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 the base layer A hexane solution (3% by weight) of γ-methacryloxypropyltris(t-butylperoxy)silane is applied using a spin coater to the back side of the side on which the optical information recording layer is formed.
The base layer 2 was formed by heating and drying with hot air at 60° C. for 5 minutes.

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 1xlO-2 torr to form a transparent thin film first layer 3 made of SiO2. The number of transparent thin film first layer 3 was 2,500.

■Formation of second layer of transparent thin film Transparent thin film! After forming the first 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 2-2) AfL203 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 transparent thin film first layer 3 and second layer 9 is 3000.
It was a person.

(Example 2-3) ZrO2 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.

For manufacturing, a titanium oxide chip was placed on a silicon oxide terquerate by sputtering 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 the composition was Si:Ti:O=2:16 (atomic ratio).

(Comparative Example 2) In this example, the transparent thin film first layer and second layer were formed, or at that time, they were formed without intervening a base layer.

Except for the boiled shell, a single-plate optical information recording medium 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 silyl peroxide compound as in this example, the change in the warp angle due to environmental changes was small. on the other hand,
Significant changes are observed in 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 silyl peroxide compound. 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 suppressed. It was found that it was possible to suppress the

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 primer layer is provided on the car than when only an inorganic compound thin film layer is provided on the car.

Table 2 The initial value of IC/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 2-5) In this example, 3000 people formed only SiO2 (transparent thin film first layer) without providing the inorganic transparent thin film second layer.

Except for this point, a single-plate optical information recording medium was produced in the same manner as in Example 2-1.

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. (R5-3200: manufactured 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.

(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 prepared as follows.

■ Formation of optical information recording layer Substrate for optical information recording medium made of polycarbonate resin (
130φ, thickness 1.2 mm), in the same manner as in Example 1-1, a Si AJlON layer (dielectric layer) with a thickness of 1,000 layers and a TbFeCo layer (recording layer) with a thickness of 300 layers and a thickness of 1 layer, respectively. S iA, lloN layer (protective layer) 300A, A
AwA (Reflection Jri 1oo.

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 the base layer A hexane solution (3% by weight) of γ-methacryloxypropyltris(t-butylno\-oxy)silane was applied to the back side of the side on which the optical information recording layer was formed using a spin coater, and the mixture was heated at 60°C. A base layer was formed by heating and drying with hot air for 5 minutes.

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 apparatus, and then evacuated to lXl0-'torr. Then,
Ar gas was introduced at 1xio-2 torr, and S i O2
A transparent thin film layer consisting of the following was formed. Transparent 'fi! The thickness of the membrane layer was 3000 people.

(2) Irradiation of electron beams After forming the inorganic transparent ia 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 using OMrad in an argon gas atmosphere.

(Example 3-2) In this example, a sample was created in the same manner as in Example 3-1 except for using A1.203 as the transparent thin film layer.

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 target and RF Sunohe Ivy was used. 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 Si: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 FIGS. 5(a) and 5(b), the samples in which a transparent thin film made of an inorganic material is provided via a silyl peroxide compound as in this example are all resistant to environmental changes. The change in warpage angle was small.

In addition, for the above four samples, 80°C, 90% R
Table 3 shows the results of a 100-time cold/heat cycle test in which the sample was left for 2 hours at H. .

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 5i AILON layer (dielectric layer) was applied in the same manner as in Example 1-1.
1TbFeC for 000 people thickness.

The layer (recording layer) is 300mm thick C1S i AJION layer (
Protective layer) lit 300 AJl and AILwA (reflective layer) were sequentially formed 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 side on which the optical information recording layer is formed, apply a hexane solution (3% by weight) of γ-methacryloxypropyl tris(t-butylnopeoxy) silane using a spin coater, and heat at 60°C. A base layer was formed by heating and drying with hot air for 5 minutes.

The thickness of this base layer was 20 people.

■Formation of the first layer of inorganic transparent thin film After forming the base layer, the substrate was introduced into the vacuum chamber of the sputtering device, and then the vacuum chamber was evacuated to 1×1O””torr.

Then, Ar gas was introduced at 1xlO-2torr, and Si
A film made of O2 was formed.

(2) Formation of second layer of inorganic transparent thin film After forming the first inorganic transparent thin 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 's1 layer and the second layer 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 /
s dose rate, dose 8. Irradiation was performed at OMrad in an argon gas atmosphere.

(Example 4-2) In this example, transparent thin 11! A and Q203 were used as the first layer.

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

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

(Example 4-3) ZrO2 was used as the first transparent thin film layer.

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

::(Dgt7) ESCA analysis revealed that the composition was 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 Figure 6(a) and Figure 6(b), all samples in which a transparent thin film made of an inorganic material is provided via a silyl peroxide compound as in this example do not warp due to environmental changes. The change in angle was small.

The above four samples were left at 80°C and 90% 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 5in2 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 point, a single-plate optical information recording medium was produced in the same manner as in Example 4-1.

The six samples of Examples 4-1 to 4-5 and Comparative Example 1-1 were used in an actual usage environment for three months, and during that time 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 Co., Ltd.).

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 8-electrode 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 releases the static electricity accumulated in the optical information recording medium into the atmosphere. The optical 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 a temperature/humidity change test 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... Dielectric, 5... Magneto-optical recording layer, 6...
...Protective layer, 7...Reflection layer, 8...Overcoat layer. Figure 1 (a) Patent applicant Hiroshi, representative of Sekisui Chemical Co., Ltd. 1) Kaoru'X-3 Figure 1 (b)

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 silyl peroxide compound is formed on the other side. 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 an inorganic material interposed therebetween.