JPH03189936A - optical disk - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to optical discs.

[Prior Art] In conventional optical discs, a substrate is hard coated, and then a recording layer is formed and bonded together. Alternatively, the recording layer was formed and then bonded together, and then the surface of the disk was hard coated. Thereafter, a hard coat agent containing an antistatic agent is used, the antistatic agent is spray applied after hard coating, or the antistatic agent is applied by a method such as a spin cord.

[Problem to be solved by the invention] However, the conventional technology had the following problems.

A hard coating agent containing an antistatic agent cannot obtain sufficient surface hardness. However, when applying the antistatic agent using an antistatic spray or spin cord method.

Initially, there is an antistatic effect, but the antistatic effect gradually becomes weaker. In addition, if the protective layer is made of a non-conductive material, when forming an organic protective layer of ultraviolet curable resin on top of it, or when bonding with adhesive, etc.
Static impurities get mixed into organic protective layers and adhesives, reducing reliability and increasing error rates.

The present invention is intended to solve such problems, and its objectives are as follows. A hard coating agent containing an antistatic agent can provide sufficient surface hardness, and the antistatic effect will not gradually become weaker, unlike when applying an antistatic agent using an antistatic spray or spin cord method.

Also, if the protective layer is made of a non-conductive material, it can be used when forming an organic protective layer of ultraviolet curable resin on top of it, or when bonding with adhesive.

Impurities due to static electricity will not be mixed into the organic protective layer or adhesive, and there will be no reduction in reliability or increase in error rate.

[Means for Solving the Problems] In the optical disc of the present invention, tracking grooves or pits are formed on one side of a substrate, and then a hard disk made of a photocurable resin is formed on the side of the substrate where the grooves or pits are not formed. A coat layer is formed, and ZnO is deposited on the hard coat layer.
A recording layer portion in which a transparent conductive film of the system is formed, and then a ceramic layer, a recording layer, a ceramic layer 9 reflective layer, and a protective layer are sequentially formed on the side of the substrate on which the grooves or pits are formed. The present invention is characterized in that two of the above-mentioned substrates each having a structure formed thereon are bonded together.

In the present invention, the adhesive includes at least an epoxy base agent and a curing agent, a mixture of an ultraviolet curable resin base agent and a curing agent, and an organic peroxide added thereto, or an epoxy group and (
A compound having a meth)acryloyl group, such as a partially (meth)acryloyl-modified epoxy compound such as bisphenol A, bisphenol F type, phenol novolac type, or ful7'-crucvolac type, is combined with a photopolymerization initiator, an epoxy curing agent, It is preferable to use one to which an organic oxide is added if necessary. In these adhesives.

The ratio of the total amount of epoxy groups to the total amount of (meth)acryloyl groups is preferably 95 to 60% for epoxy groups and 5 to 40% for (meth)a3-4-acryloyl groups. Preferably, 90 to 80% epoxy groups and 10 to 20% (meth)acryloyl groups are suitable.

Examples of epoxy base agents include bisphenol A,
For bisphenol F series, novolac series, etc.

or by adding a reactive diluent, which is a low viscosity epoxy.

It is better to use one without adding it. When the content of the reactive diluent increases, the viscosity of the adhesive decreases and workability improves, but the heat resistance of the adhesive layer decreases.

It is better to limit the amount of addition as it will reduce the reactivity and deteriorate the properties of the adhesive layer.

Epoxy curing agents include acid anhydrides, aromatic amines, aliphatic amines, amides, etc. Among them, it is best to use one with a pot life of 1 to 50 hours at room temperature.
It is advisable to select a curing agent that can be cured at temperatures ranging from 'C to 80°C.

Examples include 2-ethyl-4methylimidazole,
Examples include imidazole series such as 1-benzyl-2-methylimidazole and 1-isobutyl-2methylimidazole, and cycloaliphatic amines such as menthanediamine.

As the main ingredient of the ultraviolet curable resin, it is best to use one that has a relatively low viscosity at room temperature and one that is highly reactive; examples include 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, Since there are neopentyl glycol diacrylate, dipentaerythritol hexaacrylate, tripropylene glycol diacrylate, etc., it is preferable to use these as the main ingredients.

As an example of the curing agent for the ultraviolet curable resin, one that absorbs at wavelengths longer than 300 nm is used. Examples include benzyl dimethyl ketal, 1-h)'roxycyclohexylphenyl ketone, 2-methyl-[4-(methylthio)
phenyl]-2-morpholino-1-propanone, benzoin, benzone ethyl ether, benzoin isobutyl ether, 1-(4-isopropylphenyl)-2-
Examples include hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 3,3-dimethyl-4-methoxybenzophenone.

Preferred examples of organic peroxides include those that decompose within several hours when heated from 40°C to 70°C;
Di-n-propyl peroxydicarbonate, di-myristyl peroxydicarbonate, cumyl peroxyneohexanoate.

di(2-ethoxyethyl) peroxydicarbonate,
Di(methoxyisopropyl) peroxydicarbonate, di(2-ethylhexyl)peroxydicarbonate, t-hexyl peroxyneodecanoate, 2,4
-dichlorobenzoyl peroxide, t-hexyl peroxybivalate.

t-butyl peroxyvivalate, 3. 5. 5
Trimethylhexanoyl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, cumyl peroxyoctoate, succinic acid peroxide, acetyl oxide, t-butyl peroxy (2-ethylhexanoate) 1 m -Toluyl peroxide, benzoyl peroxide, t-
Butyl peroxyisobutyrate, 1. 1-bis(1-butylperoxy) 3. 3. 5-1 Limethylcyclohexane.

1.1-bis(t-butylperoxy)cyclohexane, t-7' tylperoxymaleic acid, t-butylperoxylaurate, t-butylperoxy3. 5.
5-trimethylhexanoate, cyclohexanone peroxide, t-butyl peroxyallyl carbonate, t-butyl peroxyisopropyl carbonate,
2. 5-dimethyl-2,5-di(benzoylperoxy)hexane.

2.2-bis(t-butylperoxy)octane.

t-butyl peroxyacetate, 2. Examples include 2-bis(t-butylperoxy)butane and t-butylperoxybenzoate.

In the present invention, the temperature during bonding must be changed depending on the viscosity of the adhesive9. Although it is preferable to set the temperature higher than normal temperature, it is preferable to set the temperature to 70° C. or lower in order to easily obtain a constant constant temperature. More preferably from 40℃ to 6
It is 0°C. The substrate heating for curing the adhesive is preferably from 40°C to 80°C, depending on the curing temperature of the adhesive. More preferably it is 50°C to 70°C.

In the present invention, as for the blending ratio of epoxy and ultraviolet curable resin, the greater the blending ratio of epoxy resin, the better the properties as an adhesive (the ratio of epoxy and ultraviolet curable resin is 95% by weight).
: 5 to 70: ao is preferred. Here, epoxy refers to an epoxy main ingredient and a curing agent, and an ultraviolet curable resin refers to an ultraviolet curable resin in which an organic peroxide is added to the main ingredient and a curing agent.

In the present invention, if the bonding is carried out under reduced pressure, the adhesive can be easily degassed and air bubbles are less likely to be incorporated into the adhesive layer.

In the present invention, it is preferable that the time for which the disks are left to stand after being bonded together and temporarily fixed by irradiation with light is set to be longer than the time for the adhesive to harden naturally. For example, if you leave it alone for 50
In the case of bonding with an adhesive that completely loses fluidity and hardens over time, it is better to set the time to 50 hours or more. 10
If the fluidity disappears after a certain amount of time, set it to 10 hours or more.

[Example code] The present invention will be explained in detail below based on the drawings.

FIG. 1 is a basic configuration diagram of the optical disc according to the present invention.
1 and 8 are polycarbonate substrates, 2 and 9 are SiA
IN layers 3 and 10 are NdDyFeCo layers 4 and 11
is a SiAIN layer, 5 and 12 are AI-Ge layers, 6 and 1 are
3 is 10 layers of ZnA.

7 is an adhesive layer, 14 and 15 are hard foot layers, 16
and 17 is a ZnA10 layer.

The polycarbonate substrates of Nos. 1 and 8 were formed by injection compression molding. The SiAIN layers 2 and 9 were formed by RF reaction magnetron sputtering using a mixed gas of nitrogen and argon using a SiAl sintered target. 3 and 10 NdDyFeC
The o layer is a DC using an alloy target of NdDyFeCo.
The film was formed by magnetron sputtering.

Similar to the SiAIN layers 2 and 9, the SiAIN layers 4 and 11 were formed by the RF reaction magnetron sputtering method by introducing a mixed gas of nitrogen and argon. AtGe layers 5 and 12 were DC-treated by introducing argon gas using an Al-Ge target.
The film was formed by magnetron sputtering.

The protective layers 9 and 13 are formed by R by introducing a mixed gas of argon and oxygen using a sintered target of ZnAl0.
The film was formed by F magnetron sputtering.

FIGS. 2(a) to 2(f) are schematic diagrams of the method for manufacturing an optical disc according to the present invention. Reference numeral 18 indicates a portion on the outer periphery of the substrate where the recording layer is not formed, 19 indicates a portion on the inner periphery of the substrate where the recording layer is not formed, 20 indicates the center hole portion of the disk, 21 indicates the dispenser, and 22 indicates the coating in a ring shape. 23 is a heater, 24 is a metal halide lamp, 25 is an ultraviolet light, and 26 is an oven.

After applying a ring-shaped adhesive as shown in 22 using a dispenser in 20, the adhesive is pasted together in a vacuum, the adhesive is spread with a heater in 23, and ultraviolet rays are irradiated with a metal halide lamp in 24. The adhesive in the area where the recording layer of No. 19 is not formed is cured, left for 24 hours to harden the adhesive to some extent, and placed in the oven of No. 26.
The adhesive layer was cured by heating at 50°C for 3 hours, 60°C for 8 hours, and 80°C for 2 hours. The adhesive was cured.

The adhesive layer in No. 7 is Epicron S-1 from Dainippon Ink and Chemicals.
29 and oil-based shell epoxy Ebicure IBMI-1
2 and 1. 6-hexanediol diacrylate and t-
A mixture of butyl peroxyisobutyrate and Irgacure 907 manufactured by Ciba Geigy was used.

The hard coat layers 14 and 15 were spin-coded with trimethylolpropane triacrylate, 1,6-benzenediol diacrylate, and Dolphincure 907 manufactured by Ciba Geigy on the substrate surface, and then cured by irradiating ultraviolet rays with a high-pressure mercury lamp. This is what I did.

The ZnAl0 layers 16 and 17 were formed by RF magnetron sputtering using a ZnA10 sintered target and introducing a mixed gas of argon and oxygen.

In addition, as the adhesive layer of No. 7, Ciba Geigy's Irgacure 907 was added to a bisphenol F-based epoxy resin in which 20% of all epoxy groups are acryloyl groups.
5%, oily shell epoxy Ebicure BMI-12
When an optical disc was prepared using 6% of γ-glycidoxypropyltrimethoxysilane and 3% of γ-glycidoxypropyltrimethoxysilane, with the other conditions unchanged from the configuration shown in Figure 1, the result was almost the same as that shown in Figure 1. An optical disc with these characteristics was created.

Next, an example of creating an optical disc using a conventional method will be described. Optical discs bonded together using the roll foot method are
When a 70'C90%RH7' 1000 hour weather resistance test was carried out, the recording layer was oxidized and the pit error rate increased. The optical disk according to the present invention shown in FIG. 1 was also tested at the same time, but there was no change in pit error rate. The optical disc bonded using a normal epoxy resin had a high viscosity at the time of bonding, so the adhesive layer was thicker and the nine-plane runout amount was larger than that of the optical disc of the present invention shown in FIG. The maximum power consumption was 7 milliradians using a normal epoxy resin, and the maximum power consumption was 2 milliradians for the optical disc shown in FIG. 1. In the case of optical discs bonded together using ordinary epoxy resin.

When the adhesive cured, it overflowed from the outer periphery of the disc, spoiling the appearance of the optical disc. Temperature control is difficult with adhesives that cure with heat, and it is necessary to ensure that the substrate does not move while the adhesive layer is curing.If the adhesive is bonded with an adhesive that cures at room temperature, stress will be applied to the recording layer when the adhesive layer hardens. The envelope of the playback signal was disturbed and errors increased. In addition, when there was no protective layer, weather resistance was poor, and pitting corrosion occurred after 1000 hours at 80°C and 90%. When a dielectric material is used as the protective layer, weather resistance is good, but it is difficult to remove dust that adheres during bonding. If they were pasted together with dust attached, the weather resistance would be poor and the pit error rate would be high.

As described above, optical disks manufactured by conventional methods have problems such as poor weather resistance and difficult manufacturing methods, resulting in low yields. However, it can be seen that the optical disc of the present invention is highly reliable and easy to produce without the problems that have conventionally occurred.

It should be noted that the present invention should not be considered limited to these embodiments, and various modifications can be made without departing from the gist of the present invention.

[Effect of the invention] As described above, according to the optical disc of the present invention.

A hard coating agent containing an antistatic agent can provide sufficient surface hardness, and the antistatic effect will not gradually become weaker, unlike when applying an antistatic agent using an antistatic spray or spin cord method. Also.

When the protective layer is made of a non-conductive material, when an organic protective layer of ultraviolet curable resin is formed on top of the protective layer, or when bonded with an adhesive, an organic protective layer or an adhesive is used. Impurities caused by static electricity will not be mixed into the product, reducing reliability.

This has the effect of not causing an increase in error rate.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of an optical recording medium according to the present invention. FIGS. 2(a) to 2(f) are schematic diagrams of the method for manufacturing an optical disc according to the present invention. 1.8... Polycarbonate substrate 2.9...
5jAIN protective layer 3, 10...-NdDyFeCo recording layer 4, 11...
... Protective layer of S fAIN 5.12 ... Al-Ge layer 6.13 ... ZnA10 layer 7 ... Adhesive layer 14.15 ... Hard coat layer 16.17 - ZnAl0 layer 18 ... Portion 19 on the outer periphery of the substrate where the recording layer is not formed... Portion 20 on the inner circumference of the substrate where the recording layer is not formed ... Center hole portion 21 of the disk...・
... Dispenser 22 ... Adhesive layer 23 applied in a ring shape...
... Heater 15- = 16- 24 ... Metal halide lamp 25 ... Ultraviolet light 26 ... Oven or higher

Claims (3)

[Claims] (1) After forming tracking grooves or pits on one side of the substrate, a hard coat layer made of a photocurable resin is formed on the side of the substrate where the grooves or pits are not formed, and on the hard coat layer. A recording layer portion in which a ZnO-based transparent conductive film is formed on the substrate, and then a ceramic layer, a recording layer, a ceramic layer, a reflective layer, and a protective layer are sequentially formed on the side of the substrate where the grooves or pits are formed. An optical disc characterized in that two of the above-mentioned substrates each having a structure formed thereon are bonded together. (2) The ZnO-based transparent conductive film is a ZnO film, ZnAl
The optical disc according to claim 1, characterized in that it is an O film, a ZnGaO film, a ZnInO film, a ZnTi film, or a mixture thereof. (3) The optical disc according to claim 1, wherein the protective layer is a ZnO-based ceramic layer.