JPH0478578A - Optical disk - Google Patents

Abstract

PURPOSE:To obtain an optical disk having a resin layer capable of well holding the shape of a group or pit even under a high temp. and high humidity condition or reduced pressure and preventing the corrosion of a recording layer by providing the resin layer cured by the irradiation with light on a substrate and specifying the gel ratio of the resin layer. CONSTITUTION:For example, an optical magnetic recording disk 1 is formed by successively providing a resin layer 3, a protective layer 4, an intermediate layer 5, a recording layer 6, a protective layer 7, a protective coating layer 8, an adhesive layer 9 and a protective substrate 10 on a substrate 2 and the gel ratio of the resin layer 3 after curing is 95% or more. The elastic modulus of the resin layer 3 at frequency of 10 Hz within the temp. range of 20-100 deg.C is pref. 200 kgf/mm<2> or more and the dynamic loss coefficient tan delta thereof is pref. 0.01-0.2. Therefore, the good resin layer 3 can be formed and, even when the disk 1 is used or preserved under a high temp. and high humidity condition, the recording layer 6 is not corroded. In addition, the shape of the group or pit for an address or tracking formed to the resin layer 3 and that of the recording pit formed thereto can be well held.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to optical disks, such as magneto-optical recording disks, phase change type optical recording disks, bit forming type optical recording disks, read-only optical disks, and the like.

<Prior Art> Among optical disks, for example, a magneto-optical recording disk is constructed by sequentially laminating a resin layer, a recording layer, a protective coat, etc. on a substrate.

In this case, an ultraviolet curable compound is usually used for the resin layer. Then, using the so-called 2P method, a resin layer having a pattern of tracking groups, bits, recording bits, etc. is formed on the substrate.

In the 2P method, first, an ultraviolet curable compound is spread on the surface of a standber having a matrix pattern of the pattern described above, and a disk-shaped substrate is pressed onto the ultraviolet curable compound. Next, after curing by irradiating ultraviolet rays, the stand bar and the resin are peeled off. As a result, a resin layer to which the master pattern has been transferred can be formed on the substrate.

<Problems to be Solved by the Invention> However, in the case of a disk having a resin layer made by curing a conventional ultraviolet curable compound, if the pressure is reduced when forming the recording layer by a vapor phase film forming method such as sputtering, the resin Gas is generated from the layer, and this gas may corrode the recording layer.

Furthermore, if the disk is used or stored at high temperatures, monomer may flow out from the resin layer and the recording layer may be corroded by this monomer.

As a result, the recording/reproducing characteristics of the disk, particularly the C/N, deteriorate, and errors occur.

In addition, groups and bits may become deformed as a result of gas generation or monomer leakage from the resin layer.

This may make focusing and tracking difficult and increase errors.

An object of the present invention is to provide an optical disc having a resin layer that can maintain the shapes of groups and bits well even under high temperature, high humidity, and reduced pressure, and that does not corrode the recording layer.

<Means for Solving the Problems> Such objects are achieved by the following inventions (1) to (5).

(1) An optical disc comprising a resin layer cured by irradiation with radiation on a substrate, the resin layer having a gel fraction of 95% or more.

(2) Frequency of the resin layer: 10 Hz, temperature: 20 to 100
The optical disc according to (1) above, which has an elastic modulus of 200 kgf/ff1m2 or more at °C.

(3) Frequency of the resin layer: 10) 1z, temperature: 20-10
The mechanical loss coefficient tan δ at 0°C is 0.01 to 0.
2. The optical disc according to (1) or (2) above.

(4) The above (1) in which a metal recording layer is formed on the resin layer.
The optical disc according to any one of 3) to 3).

(5) The optical disc according to any one of (1) to 3) above, which has a recording layer formed on the resin layer under an atmospheric pressure of 5 Pa or less.

<Function> The optical disc of the present invention has a resin layer with a gel fraction of 95% or more.

Therefore, even when the disk is used or stored at high temperature and high humidity, gas is hardly generated from the resin layer or monomer components are hardly leaked.

Particularly in the case of an optical recording disk in which the recording layer is formed by a vapor phase film forming method such as sputtering, gas is hardly generated from the resin layer even if the pressure is reduced when forming the recording layer.

Therefore, it is possible to form a good recording layer, and even if the disc is used or stored at high temperature and high humidity,
The recording layer will not corrode.

In addition, the shapes of addressing or tracking groups, bits, recording bits, etc. formed in the resin layer can be well maintained.

In addition, since the gel fraction of the resin layer is not determined only by the ultraviolet curable compound used, in the present invention, it is determined by the ultraviolet curable compound, the photopolymerization initiator, their contents, the ultraviolet irradiation conditions, the atmosphere, etc. A resin layer having a desired gel fraction is formed by combining various conditions.

<Specific configuration> Hereinafter, a specific configuration of the present invention will be explained in detail.

The optical disc of the present invention has a resin layer cured by irradiation with radiation on a substrate.

In this case, the present invention relates to both a read-only optical disc that previously carries information and an optical recording disc that has a recording layer that carries information.

However, here, explanation will be given by taking the magneto-optical recording disk shown in FIG. 1 as a preferred example.

This magneto-optical recording disk l has a resin layer 3 on a substrate 2,
It is a single-sided recording type having a protective layer 4, an intermediate layer 5, a recording layer 6, a protective layer 7, a protective coat 8, an adhesive layer 9, and a protective substrate 10 in this order.

In the present invention, the substrate 2 is transparent to recording light and reproduction light, and its material may be glass, resin, etc., which are conventionally known as substrate materials for optical discs.
It is selected as appropriate depending on the purpose and the like. In this case, it is preferably made of resin or glass, more preferably glass.

If the substrate 2 is made of glass, heat resistance and moisture resistance will be improved, and birefringence will hardly occur.

In the case of a glass substrate, it is preferably made of tempered glass. By using tempered glass, higher rigidity, better weather resistance, and durability can be obtained.

There are no particular restrictions on the tempered glass used in the present invention, and physically strengthened glass or chemically strengthened glass strengthened using a normal strengthening method may be used, but chemically strengthened glass is preferably used.

In the case of a resin substrate, for example, acrylic resin, polycarbonate, epoxy resin, polymethylpentene, polyolefin, etc. are suitable.

The shape of the substrate 2 is a disk, and the outer diameter is usually 50 mm.
~36oIII11 degree, inner diameter is usually 15-60m
The thickness is usually about 0.5 to 2 mm.

Note that the substrate 2 may be manufactured according to a known method.

A resin layer 3 is provided on the substrate 2 .

The resin layer 3 is made of a material obtained by curing a radiation-curable compound or its composition by irradiating it with radiation such as ultraviolet rays or electron beams, and has bits or groups on its surface for tracking, addressing, etc. It has a predetermined pattern such as.

The gel fraction of the resin layer 3 after curing is 95% or more, preferably 97% or more.

If it is less than the above range, when the disk is placed under high temperature, high humidity, or reduced pressure, gas will be generated from the resin layer 3, monomer will flow out, and the recording layer 6 will corrode.

Then, as a result of gas being generated from the resin layer 3 or monomer flowing out, the groups and bits of the resin layer 3 are deformed.

The gel fraction of the resin layer 3 may be measured as follows.

First, a resin layer is formed on a substrate under the same conditions as when manufacturing a disk.

Next, a sample piece of yg (approximately 0.5 to 1.0 g) is scraped off from the resin layer and dissolved in, for example, acetone by applying ultrasonic waves.

Then, the insoluble matter is weighed, and this is set as xg to calculate from the following formula.

Formula (x/y) X 1 00 (%)
In the present invention, the gel fraction of the resin layer 3 can be increased to nearly 100% ( It can be done.

In addition, the frequency of the resin layer 3 after curing is 10 Hz, 20 to 10
The elastic modulus at each temperature within the temperature range of 0°C is 200
kgf/am” or more is preferable.

If the elastic modulus is 200 kgf/+rs” or more, 2P
When forming the resin layer 3 on the substrate by the method, the resin can be easily peeled off from the stand bar.

In addition, since the shapes of the formed groups and pits can be maintained as they are, it is possible to form a resin layer in which the master pattern of the stamper is accurately transferred.

The resin layer 3 has heat resistance, i′4 humidity, and further,
Membrane strength is improved.

Therefore, if the disk is placed under high temperature and high humidity, for example, when forming the recording layer 6 by a vapor phase film formation method such as sputtering, or when the disk is stored under high temperature and high humidity, Even during use, the resin layer 3 does not deform, and the mechanical precision of the disk can be maintained at a high level.

However, if the elastic modulus of the resin layer 3 is too large, the resin layer 3 may become too brittle and cracks may occur due to changes in temperature and humidity.
It is preferable that

And more preferably 220 to 1500 kgf/mm
", especially 250 to 1000 kgf/mm" is preferable.

When the elastic modulus is within the above range, the effects described above such as improved heat resistance and the effects of the present invention are further improved.

In addition, the frequency of the resin layer 3 after curing is 10 Hz, 20 to 10
Mechanical loss coefficient ta at each temperature within the temperature range of 0°C
It is preferable that nδ is 0.01 to 0.2.

If the above range is exceeded, the viscosity of the material increases and the group shape tends to change due to heat.

If it is less than the above range, the resin layer 3 itself becomes too brittle and cracks are likely to occur due to changes in temperature and humidity.

Moreover, the film forming ability is degraded.

And more preferably 0.05 to 0.2, especially 0.0
It is preferable that it is 5-0.18.

When tan δ is within the above range, the effects described above such as improved heat resistance and the effects of the present invention are further improved.

In addition, the elastic modulus and tan δ of the resin layer 3 are also the same as the gel fraction.
A desired composition may be obtained by combining various conditions such as the radiation-curable compound, the photopolymerization initiator, or the content thereof, ultraviolet irradiation conditions, and atmosphere.

The elastic modulus and mechanical loss coefficient tan δ of the resin layer 3 are measured as follows.

For example, a resin layer is formed on release paper to a thickness of 100 to 500 pm. Next, the resin layer is peeled off from the release paper, and measured using a viscoelasticity measuring device at an excitation frequency of 10 Hz (sine wave) at a temperature of 0 to 150° C. using a forced vibration method.

The resin material constituting the resin layer 3 is not particularly limited as long as the gel fraction described above is obtained, and may be appropriately selected from various radiation-curable compounds used in the so-called 2P method.

Suitable monomers to be used include monofunctional, difunctional, trifunctional, or polyfunctional ester acrylates, urethane acrylates, polypropylene acrylates, and the like.

In this case, only one type of nanatsumer may be used, but it is preferable that the above-mentioned gel fraction, furthermore, the elastic modulus and tan δ are easily obtained.
In some cases, three or more species may be used.

Among the above-mentioned monomers, trifunctional monomers such as trimedylolpropane triacrylate, pentaerythritol triacrylate, and trimethylolpropane trimethacrylate, and neobentyl glycol 5-hydroxypivalate diacrylate, caprolactone-modified neopentyl glycol hydroxypivalate, etc. It is best to use it in combination with bifunctional monomers such as diacrylate and neopentyl glycol dimethacrylate.

Also, instead of or in addition to the monomer,
One kind or two or more kinds of oligomers may be used in combination.

As the oligomer, oligoester acrylate and the like are suitable.

As polyfunctional oligoester acrylate, Aronix M-8100, M-6500 (manufactured by Toagosei Kagaku Co., Ltd.)
Commercially available products can be used, and these are represented by the following formula % formula % A Niacrylic acid, X: Polyhydric alcohol, M: Dihydric alcohol, Y: Polybasic acid, N: Dibasic acid Also, monomers and In addition to the oligomer, a photoinitiator is usually added.

There is no particular restriction on the photopolymerization initiator used, but for example, 2
．． 2-dimethoxy-2-phenylacetophenone, 2-
Ketones such as methyl-[4-(methyldio)phenyl]-2-morpholino-1-propanone, benzoin, benzophenone, and benzyl are preferred.

The content of the photopolymerization initiator is 1 to 10% by weight, especially 3 to 5% by weight.
Weight percent is preferred.

In this case, in the present invention, it is preferable that additives such as solvents are not contained.

It is preferable that the resin layer 3 is formed by the known 2P method.

In the 2P method, first, a radiation-curable compound, preferably a radiation-curable compound to which a photopolymerization initiator is added, is spread on the surface of a stand bar having a predetermined pattern, and the substrate 2 is pressed onto this coating film. This pressure contact transfers the pattern on the standber surface to the coating film surface.

Next, the coating film is cured by irradiating radiation, preferably ultraviolet rays, through the substrate 2 to bond the resin and the substrate 2, and then the resin and the stand bar are separated.

Through the above steps, the resin layer 3 to which the standby pattern has been transferred is formed on the surface of the substrate 2.

Note that the elastic modulus of the resin layer 3 after curing is 200 kgf/mm.
If the above-mentioned restrictions are applied, the resin and the stand bar can be easily separated, and the formed groups and bits can be maintained in a good shape.

Various known methods may be used to cure the coating film with ultraviolet rays.

For example, a xenon discharge tube, an ultraviolet light bulb such as a high-pressure mercury lamp, etc. may be used.

Further, depending on the case, an electron beam or the like may be used.

There are no particular restrictions on the conditions for curing the coating film, and for example, the following conditions may be used.

Radiation dose: about 0.3 to 2 joules/cm'' Note that there are no particular restrictions on the atmosphere during curing (for example, the atmosphere may be used).

However, when using a radiation-curable compound with anaerobic curing properties, an inert gas atmosphere such as Ar, N2 gas atmosphere, etc. are suitable.

The layer thickness of the resin layer 3 formed in this way is preferably 5 to 100M, more preferably 30 to 50μ.

If it is less than the above range, the resin layer 3 is too thin and tends to be insufficiently cured.

If the thickness exceeds the above range, the resin layer 3 will be too thick, the inside of the layer will tend to be uncured, and wrinkles will easily occur.

The intermediate layer 5 is provided to improve the C/N ratio, and is preferably formed from various dielectric materials, and preferably has a layer thickness of about 30 to 150 nm.

Note that such an intermediate layer material may be provided as a protective layer 7 on a recording layer 6 to be described later, and used in combination with the intermediate layer 5. When used together, the compositions of the intermediate layer 5 and the protective layer 7 may be the same or different.

The protective layer 4 and the protective layer 7, which are provided as necessary, are provided to improve the corrosion resistance of the recording layer 6, and it is preferable that at least one of them, and preferably both, be provided.

These protective layers are preferably composed of inorganic thin films made of various oxides, carbides, nitrides, sulfides, or mixtures thereof. Further, as mentioned above, the protective layer may be formed of the above-mentioned intermediate layer material, and the thickness of the protective layer is 30 to 3
00 r+n+ is preferable from the viewpoint of improving corrosion resistance.

The protective layer 4.7 and intermediate layer 5 are preferably formed by various vapor phase deposition methods such as sputtering.

Information is magnetically recorded in the recording layer 6 using a modulated heat beam or a modulated magnetic field, and the recorded information is reproduced by magneto-optical conversion.

The material of the recording layer 6 is not particularly limited as long as it can perform magneto-optical recording, but alloys containing rare earth metal elements, particularly alloys of rare earth metals and transition metals, may be used by sputtering, vapor deposition, or ion beam deposition. It is preferable that the film be formed as an amorphous film by a rating method or the like.

Rare earth metals include Tb, Dy, Nd, Gd, Sm,
It is preferable to use one or more types of Ce.

As the transition metal, Fe and CO are preferred.

In this case, the total amount of Fe and CO is 65 to 85 at%
It is preferable that

The remainder is substantially rare earth metal.

The composition of the recording layer suitably used is TbFeCo, DyTbFeCo, NdDyFeC.
o, NdGdFeCo, etc.

In addition, the recording layer contains Cr and A in a range of 10 at% or less.
A, Ti, Pt, Si, Mo, Mn, ■, Ni, Cu,
Zn, Ge, Au, etc. may be contained.

In addition, in the range of ]Oat% or less, Sc, Y, La, Ce
, Pr, Pm, Sm, Eu, Ho.

It may also contain other rare earth metal elements such as Er, Tm, Yb, and Lu.

The thickness of such recording layer 6 is usually 10 to 11,000.
It is about n.

Although it depends on the method of forming the recording layer 6, for example, in sputtering, the pressure is reduced to about 5 Pa or less, particularly about 0.5 to 3 Pa, and at this time, the disk is placed at a temperature of about 60 to 100°C. However, since the resin layer 3 has a gel fraction of 95% or more and a small amount of 7-mer component, there is almost no gas generation or 7-mer outflow.

As described above, the effects of the present invention can be obtained particularly under reduced pressure such as in a vapor phase film forming method, for example, at an atmospheric pressure of about 5 Pa or less, particularly at a pressure of about 0.5 to 3 Pa, or at a high temperature, for example, at a pressure of 60 to 100 Pa.
This phenomenon is noticeable when the recording layer 6 is formed at a temperature of about .degree.

The protective coat 8 is provided to improve corrosion resistance and scratch resistance, and is preferably composed of various organic substances. It is preferable that the material is made of a material cured by radiation such as UV rays or ultraviolet rays.

The thickness of the protective coat 8 is usually about 0.1 to 100 mm.

Such a coating film may usually be formed by combining various known methods such as spinner coating, gravure coating, spray coating, and dipping.

The protective substrate 10 is provided as necessary to effectively prevent damage to the recording layer 6, and is usually made of glass or resin.

The thickness of the protective substrate 10 is usually set to a certain value in order to ensure rigidity.
The thickness should be approximately 0.5 to 2.0 mm.

The protective substrate 10 includes, for example, an adhesive layer 9 as shown in the figure.
is bonded and integrated with the substrate 2.

There are no particular restrictions on the adhesive used, but hot melt adhesives are preferred.

Botmelt adhesives generally consist of a base polymer, to which additives such as tackifiers, softeners, plasticizers, and waxes are added.

For adhesion, for example, when using a Botmelt adhesive, a roll coater or the like may be used.

The thickness of the adhesive layer 9 is usually about 10 to 10,000 m.

Although the optical disk of the present invention is applied to a single-sided recording type magneto-optical recording disk, it can also be applied to a double-sided recording type magneto-optical recording disk.

A double-sided recording type magneto-optical recording disk is obtained by preparing two substrates 2 having each of the above-mentioned constituent layers and adhering them with, for example, an adhesive layer 9 so that the recording layer 6 is encapsulated therein.

Furthermore, the present invention can also be applied to optical recording disks that have a so-called phase change type recording layer and perform recording and reproduction by changing reflectance.

As such a recording layer, for example,
Te- as described in No. 902 and Patent No. 1004835
5e series alloy, T described in JP-A-62-76035 etc.
e-Ge based alloys, Te-In based alloys described in JP-A No. 63-56827, TeSn-based alloys described in Japanese Patent Applications JP-A-61-307298, JP-A-61-307299, etc., JP-A-58 -54338, Patent No. 974257,
TeM compound system described in Patent No. 974258, Patent No. 974257, etc., various other chalcogen systems mainly composed of Te and Se, alloys that cause amorphous-crystalline transition such as Ge-3n and 5i-Sn, Ag- Zn, Ag-Al! , -Cu, Cu-Aj2, etc. alloys that change color due to changes in crystal structure, In-5b
There are alloys that cause changes in crystal grain size.

Furthermore, the present invention can also be applied to an optical recording disk having a so-called bit-forming type recording layer in which the reflectance changes due to bit formation.

The bit-forming recording layer may contain pigments such as cyanine, phthalocyanine, naphthalocyanine, anthraquinone, azo, triphenylmethane, biryllium or thiapyrylium salts, or Te-based pigments mainly containing Te. material is used.

In addition, the present invention may be applied to playback-only optical discs such as optical video discs and optical digital audio discs. However, among the above, preferred are phase-change optical recording disks having a recording layer containing a metal, in particular a recording layer of a metal, in which the recording layer is formed under reduced pressure by a vapor phase deposition method, and a rare earth metal element, etc. This is a magneto-optical recording disk having a recording layer containing a metal, particularly a metal recording layer.

In the case of an optical disc having a recording layer containing such a metal, the disc is heated under reduced pressure, for example, 5
Since the resin layer is placed under an atmospheric pressure of about Pa or less, especially about 0.1 to 3 Pa, and at a high temperature, for example, about 60 to 100 degrees Celsius, by forming the resin layer, It is possible to reduce the generation of gas and the outflow of water.

Therefore, an optical disc having a good recording layer and a resin layer in which groups and bits of good shape are formed is realized.

<Example> Hereinafter, the present invention will be explained in further detail by giving specific examples of the present invention.

[Example I] A resin layer 3, a glass protective layer 4, etc. are sequentially formed on a glass substrate 2. S
An iNx intermediate layer 5, a TbFeCo recording layer 6, a SiNx protective layer 7, and a protective coat 8 are formed, and finally an adhesive layer 9 is formed.
A single-sided recording type magneto-optical recording disk shown in FIG. 1 was manufactured by adhering a resin protective substrate IO.

The glass substrate 2 was made of alumina-silicate-based chemically strengthened glass, and was shaped like a disk with an outer diameter of 200+ nm and a thickness of 1.2 mm.

The resin layer 3 was formed to a thickness of 30 mm by the 2P method, and tracking groups were formed on its surface.

In this case, the following UV-curable monomers and photopolymerization initiators were used.

UV-curable monomer A1 Nitrimethylolpropane triacrylate Photoinitiator B1: 2,2-dimethoxy-2-phenylacetophenone Photoinitiator B2: 2-Methyl-[4-(methylthio)phenyl]-2-morpholino-1 -Propanone UV curable monomer A2
: Hydroxypivalic acid neopentyl glycol diacrylate CH,=CHC0CI (2 Samples with different resin layers using a composition in which the above AI, A2, B1 and B2 were mixed at the blending ratio (weight ratio) shown in Table 1. N011~No.

3 was manufactured.

A high-pressure mercury lamp was used to cure the resin, and the curing conditions were as follows.

UV irradiation amount: 1 joule 7 cm" Maximum radiant flux 2 0.1 watts/cm" Atmosphere 2 N, in gas The protective layer 4, intermediate layer 5, recording layer 6 and protective layer 7 were each formed by sputtering. The film was formed using

In addition, the protective coat 8 is formed by coating the oligoester acrylate and then cross-linking and curing it by irradiating it with ultraviolet rays.
The layer was set at 0-.

The adhesive layer 9 was formed using a hot melt adhesive using a roll coater, and had a thickness of 80 μm.

The gel fraction, elastic modulus and mechanical loss coefficient tan δ at 20° C. and 100° C. of the resin layer 3 of each sample obtained are as shown in Table 1.

In this case, the gel fraction was measured as follows.

A resin layer was formed on a glass substrate under the same conditions as when manufacturing a disk, and a 1 g sample piece was scraped off from this resin layer.

Next, the sample piece was placed in 50 mj of acetone and dissolved using ultrasonic waves for 1 hour.

Then, the insoluble matter in acetone was weighed, and this was set as xg, which was calculated from the following formula.

Formula (x/1)X100(%) In addition, the elastic modulus and mechanical loss coefficient tan δ were measured as follows.

Apply the resin layer onto release paper using a roll coater to a thickness of 100~
It was coated to a thickness of 500μ and cured under the same conditions as the sample. The obtained resin layer was peeled off from the release paper, and the excitation frequency (
Sine wave) 10) Measured at 1z between 0 and 150°C.

The same magneto-optical recording was performed on each of the obtained samples under the same conditions.

In this case, the recording signal was a rectangular signal with a duty of -50150, and the recording frequency was IMHz.

Then, the pit error rate of the disc was measured using OMS-1000 (manufactured by Nakamichi) under the following conditions.

Disk linear velocity: 4 m/sec Optimum recording sensitivity P'W: 3.8 mW Reading power: 1 mW Each sample was then placed in an atmosphere with a temperature of 80° C. and a humidity of 80% RH and stored for 500 hours.

After that, the pit error rate was measured in the same manner as above.

The results are shown in Table 2.

Initial table After aging 1 (invention) t, oxlo-st, 3xxo”2
(This invention) 1.2x 10-' 1.4x
10-'3 (Comparison) 5.0×10 bow Unmeasurable In addition, the mechanical accuracy of each sample was measured using an optical disk mechanical property measuring device 0DA-n (manufactured by Shindenshi Kogyo).

The measurement conditions were: disk rotation speed: 1800 rpm;
Laser power: 1mW, inner circumference of disk r = 55
Mechanical accuracy was measured every 5 mm from mm to outer circumference r=95a+m.

As a result, comparative sample No. 3 had many tracking errors, poor eccentric acceleration and roundness of the disk,
It was confirmed that the mechanical precision of the disc was low.

In contrast, samples No. 1 and No. 1 of the present invention
, 2, it was confirmed that the eccentric acceleration etc. were small and the mechanical precision of the disk was high.

In addition, samples No. 1 and No. 2 of the present invention
When forming the resin layer 3, that is, after curing with ultraviolet rays, it was easy to separate the resin from the stand bar.

Furthermore, it was possible to accurately transfer the master pattern of the stand bar, and to maintain the shape of the formed group well.

In addition, recording/reproducing characteristics such as C/N after aging were also good.

From these results, the effects of the present invention are clear.

[Example 2] A phase-change type optical recording disk sample that performs recording and reproduction by changing reflectance was manufactured in the same manner as in Example 1 except that the recording layer 6 was changed to a Te-5n alloy.

In this case, the recording layer 6 was formed by high frequency magnetron sputtering.

Then, when each sample was evaluated in the same manner as in Example 1, the same results were obtained.

The effects of the present invention are clear from the above results.

Loops and bits can be held in good shape, and the recording layer can also be held well.

Therefore, compared to conventional optical discs, recording/reproducing after aging, especially C/N, is improved, and in addition, error rate is reduced.

<Effects of the Invention> The optical disc of the present invention does not generate gas from the resin layer even if it is placed under reduced pressure, high temperature, and high humidity during the formation of each layer such as the recording layer during the intermediate process of manufacturing the disc. There is almost no leakage of snails.

Therefore, an optical disc having a resin layer in which well-shaped groups and bits are formed is realized.

Particularly in the case of an optical recording disk, a good recording layer can be formed.

In addition, even if the disc is stored or used in high temperature and high humidity conditions, the glue that forms on the resin layer will be removed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the optical disc of the present invention. Explanation of symbols 1... Magneto-optical recording disk 2... Substrate 3... Resin layer 4... Protective layer 5... Intermediate layer 6... Recording layer 7... Protective layer 8... Protective coat 9...Adhesive layer 10...Protective substrate Applicant: TDA-K Co., Ltd. Agent Patent attorney Seika Ishii Patent attorney
Increase 1) Tatsuya FIG, 1

Claims (5)

[Claims] (1) An optical disc comprising a resin layer cured by irradiation with radiation on a substrate, the resin layer having a gel fraction of 95% or more. (2) Frequency of the resin layer: 10 Hz, temperature: 20 to 100
The optical disc according to claim 1, having an elastic modulus of 200 kgf/mm^2 or more at °C. (3) Frequency of the resin layer: 10 Hz, temperature: 20-100
Mechanical loss coefficient tan δ at °C is 0.01 to 0.2
The optical disc according to claim 1 or 2. (4) The optical disc according to any one of claims 1 to 3, wherein a metal recording layer is formed on the resin layer. (5) The optical disc according to any one of claims 1 to 3, further comprising a recording layer formed on the resin layer under an atmospheric pressure of 5 Pa or less.