JPH03189937A - Optical disk - Google Patents

Abstract

PURPOSE:To suppress the sticking of dust and the possibility of breakdown of a head by forming a ZnO-based transparent conductive film on a hard coating layer and thereafter adhering two substrates forming a recording layer part on a side where the grooves or pits are successively formed. CONSTITUTION:Hard coating layers 7, 16 consisting of a photosetting resin are formed on a side where grooves or pits of the substrates 1, 10 are not formed and ZnO-based transparent conducting films 8, 17 are formed thereon, then, two substrates 1, 10 where ceramic layers 2, 11, recording layers 3, 12, ceramic layers 4, 13, reflecting layers 5, 14, and protective layers 6, 15 are successively formed are adhered on a side where grooves or pit are formed. By this constitution, the sticking of dust on the substrate surfaces due to the generation of electrostatic force for long period of the possibility of breakdown of the head can be reduced.

Description

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

[Conventional technology] Conventional optical discs are manufactured by applying a node coating to the substrate.
A recording layer was formed and bonded together. Alternatively, after forming a recording layer, it is pasted together and then a hard coat is applied to the surface of the disk. Then, a transparent conductive film of ITO, a metal film of silver, gold, platinum, etc., an antistatic agent, etc. are formed on the hard coat layer.

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

Antistatic agents have low conductivity and lack long-term stability. Metal films such as silver, gold, and platinum lose their transparency when applied thickly, and have problems with adhesion and conductivity when applied thinly. IT
O requires high heat to form a stable film, and there is a risk of substrate deformation.

The present invention is intended to solve such problems, and its objectives are as follows. ZnO-based transparent conductive film, ZnO film, ZnAl0 film, ZnGa
By using an O film, a Zn1nO film, a ZnTiO film, or a mixture thereof, the film has sufficient transparency and conductivity and can be formed even at low temperatures, making it easy to form and preventing the substrate from being deformed by heat during film formation. By creating a transparent conductive film with long-term stability that does not change its transparency and conductivity over a long period of time, there is no risk of dust adhering to the substrate surface or damage to the head due to static electricity generation over a long period of time. There are fewer restrictions on the handling environment.

[Means for Solving the Problems] The optical disc of the present invention has a tracking groove or bit formed on one side of a substrate, and then a hard disk made of a photocurable resin on the side of the substrate where the groove or bit is 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 was formed, and then a ceramic layer, a recording layer, a ceramic layer 1 reflective layer, and a protective layer were sequentially formed on the side of the substrate on which the grooves or bits were formed. The present invention is characterized in that two of the above-mentioned substrates each having a 3- layer formed thereon are bonded together.

ZnO film, ZnAl0 film, ZnGaO film,
Regarding a ZnInO film, a ZnTIO film, or a film of a mixture thereof, these oxides need to be somewhat reducing, since they lose their conductivity when the metal and oxygen combine in a completely saturated state. Therefore, if Zn xoy, then X>Y must be satisfied.

The content of AI, Ga, In, and TI added to ZnO is preferably less than 10% of the Zn content. Preferably it is between 8% and 2%, more preferably between 6% and 3%. By doing so, the long-term stability, transparency, and conductivity of the film can be ensured. The thickness of these films is preferably between 50 angstroms and 1000 angstroms, preferably 1
00 angstroms to 500 angstroms,
More preferably, the thickness is between 150 angstroms and 350 angstroms.

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

4- FIG. 1 is a basic configuration diagram of an optical disc according to the present invention,
1 and 10 are polycarbonate substrates.

2 and 11 are 5IAIN layers, 3 and 2 are NdDyFe
(o layer, 4 and 13 are 5IAIN layers, 5 and 14 are AI
Tf layers, 6 and 15 are 5IAIN protective layers, 7 and 16
is a hard coat layer, 8 and 17 are ZnA10 layers, and 9 is an adhesive layer.

The polycarbonate substrates of Nos. 1 and 10 were formed by injection compression molding. The S 1AIN layers of 2 and 11 are S i
The film was formed by RF reaction magnetron sputtering using a mixed gas of nitrogen and argon using a sintered Al target. 3 and 12 NdDy
The FeCo layer was formed by DC magnetron sputtering using an alloy target of N(IDyFeCo).

Similar to the 5IAIN layers 2 and 11, the 5IAIN layers 4 and 13 were formed by the RF reaction magnetron sputtering method by introducing a mixed gas of nitrogen and argon. The AlTi layers 5 and 14 were formed by DC magnetron sputtering using an AlTi alloy target and introducing argon gas. The 5iAIN protective layers of Nos. 6 and 15 were formed by RF magnetron sputtering using a 5iAIN sintered target and introducing a mixed gas of argon and nitrogen.

FIG. 2 is a schematic diagram of a method for manufacturing an optical disc according to the present invention. 18 is a portion on the outer periphery of the substrate where the recording layer is not formed; 19 is a portion on the inner periphery of the substrate where the recording layer is not formed;
20 is the center hole of the disk, 21 is a dispenser, 22 is an adhesive layer applied in a ring shape, 23 is a heater, 24 is a metal halide lamp, 25 is an ultraviolet ray, 2
6 is an oven.

The adhesive layer in No. 9 is Epicron S-1 from Dainippon Ink and Chemicals.
29 and oiled shell epoxy shrimp, cure TBMI-
12 and 1,6-hexanediol diacrylate and t-
A mixture of butyl peroxyisobutyrate and Ciba Geigy's Irgacure 907 is applied in a ring shape as shown in 22 on the side where the recording layer is formed, and then combined with another substrate in a vacuum system. Spread the adhesive on the bonded substrates using a heater (No. 23), and irradiate it with ultraviolet light using a metal halide lamp or high-pressure mercury lamp (No. 24).

The adhesive in the areas where the recording layer was not formed, such as Nos. 18 and 19, was temporarily cured, and then left to stand for 24 hours to cure the adhesive layer. Then 508C using 26 ovens
The adhesive layer was cured by heating at 606°C for 3 hours, 8 hours at 80°C, and 2 hours at 80°C.

Further, it is better to set the thickness of the adhesive layer to 60 μm or less since it is better from the viewpoint of weather resistance and manufacturing method. Preferably 50μ or less.

More preferably, the amount of adhesive is adjusted to be 40μ or less, and the degree of plausibility when spreading the adhesive is adjusted.

Alternatively, it is preferable to press or the like when bonding.

The hard coat layers 7 and 16 are made of trimethylolpropane triacrylate and 1. After spin-coding 6-hexanediol diacrylate and Irgacure 907 manufactured by Ciba Geigy on the surface of the substrate, it was cured by irradiating ultraviolet rays with a high-pressure mercury lamp.

The ZnAl0 layers of Nos. 8 and 17 were formed to a thickness of 250 angstroms by RF reaction magnetron sputtering using a sintered target of ZnA1 and introducing a mixed gas of argon and oxygen.

In addition, as the adhesive layer of No. 9, 1.5% of Ciba Geigy's Irgacure 907 was added to the compound in which 20% of the total epoxy groups of bisphenol F-based epoxy resin are acryloyl groups.
%, 6% of oily shell epoxy Ebicure BMI-12, and 3% of γ-glycidoxypropyltrimethoxysilane were used to make an optical disc, with the other conditions unchanged from the configuration shown in Figure 1. As a result, an optical disc having almost the same characteristics as shown in FIG. 1 was created.

Next, an example of creating an optical disc using a conventional method will be described. Optical discs bonded together using the roll coating method are
When a weather resistance test was conducted at 70° C. and 90% RH for 1000 hours, the recording layer was oxidized and the pit error rate increased. An optical disk according to the present invention shown in FIG. 2 as shown in FIG. 2 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 amount of surface runout 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. Also, 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 harden 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 hardens at room temperature, stress will be applied to the recording layer when the adhesive layer hardens. The envelope of the reproduced signal was disturbed and errors increased. As mentioned above, optical discs created using conventional methods have poor weather resistance,
It has problems such as the difficulty of creating it.

Table 1 shows the results of changes in electrical conductivity before and after the weather resistance test when the optical disk according to the present invention and the optical disk formed by the conventional method were subjected to a weather resistance test at 70° C. 90% for 1000 hours.

Table 1 As can be seen from the results in Table 1, the optical disk of the present invention has sufficient transparency and conductivity, and can be formed even at low temperatures.
By creating a transparent conductive film that is easy to form, does not deform the substrate due to heat during film formation, and has long-term stability in which transparency and conductivity do not change over a long period of time, the substrate is free from static electricity generation. Since there is no risk of dust adhering to the surface or damage to the head, the optical disc has long-term reliability with fewer restrictions in the handling environment.

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. For example, in the second invention, the transparent conductive film is formed after hard coating the substrate, but it is not limited to immediately after the hard coating, but may be after forming the recording layer portion or after bonding.

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

ZnO film, ZnAl0 film for ZnO-based transparent conductive film.

ZnGaO film, Zn1nO film, ZnT10 film,
Alternatively, by using a mixed system of these, the film has sufficient transparency and conductivity, and can be formed even at low temperatures.

By creating a transparent conductive film that is easy to form, does not deform the substrate due to heat during film formation, and has long-term stability in which transparency and conductivity do not change over a long period of time, the substrate is free from static electricity generation. Since there is no risk of dust adhering to the surface or damage to the head, there are fewer restrictions on the handling environment.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of an optical recording medium according to the present invention. FIG. 2 is a schematic diagram of a method for manufacturing an optical disc according to the present invention. 1, 10 2, 11 3, 12 4, 13 5, 14 6, 15 7, 16 Polycarbonate substrate 5i AIN protective layer NdDyFeCo recording layer 5i AIN protective layer AlTi layer 5i AIN protective layer hard coat layer 11 = 12- 8.17-.ZnAl0 layer 9...adhesive layer 18...portion 19 on the outer periphery of the substrate where the recording layer is not formed...portion on the inner periphery of the substrate where the recording layer is not formed 20... Disc center hole part 21...
Dispenser 22...Adhesive layer 23 applied in a ring shape...
・ ・Heater 24...Metal halide lamp 25...Ultraviolet light 26...Oven y, +7.・、muφ4

Claims (2)

[Claims] (1) After forming tracking grooves or pits on one side of the substrate, forming a hard coat layer made of a photocurable resin on the side of the substrate where the grooves or pits are not formed,
A ZnO-based transparent conductive film is formed on the hard coat layer, 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 recording layer portion 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 ZnTiO film, or a mixture thereof.