JPH0963133A - Production of substrate for optical information recording medium and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable high-speed dry treatment by generating activated species such as excited species and ions of oxygen by electric discharge under atmospheric pressure and allowing them to react with a substrate so that a UV- curing resin is allowed to adhere to the substrate. SOLUTION: Gaseous helium and oxygen are fed from a gas feeder 5 into a metallic cover 2 and substd. for an atmosphere near an electrode 3 for causing electric discharge and an amorphous polyolefin substrate 1. Electric discharge is caused between the electrode 3 and the substrate 1 by supplying high-frequency power from a high-frequency power source 4 to the electrode 3 to form an electric discharge part 7. In this part 7, various reactions by plasma such as dissociation, ionization and excitation take place, the surface of the substrate is subjected to the breaking of molecular bonds and oxidation, and the coatability of the substrate with a UV-curing resin and the adhesion of the resin are improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method suitable for a substrate for an optical information recording medium for performing optical writing and reading by a laser and the like and a manufacturing apparatus therefor.

[0002]

2. Description of the Related Art Conventionally, in an optical information recording medium such as an optical disk or an optical card, information is recorded by forming minute optically detectable pits on a track in a thin recording layer provided on a substrate. High-density recording can be performed. In such an optical information recording medium, it is necessary to scan a laser beam along a track when recording and reproducing information, and therefore, a substrate having a guide groove for tracking is generally used.

The guide groove and the substrate having the guide groove are manufactured by a compression molding method in which a softened plastic material is pressed by a stamper and then solidified, and a plastic material melted in a die in which the stamper is arranged. An injection molding method of injecting and solidifying a material and a 2P method of transferring a guide groove from a stamper using an ultraviolet curable resin are known, but the transfer property of the guide groove, the solvent resistance of the substrate and the optical property of the substrate are known. The 2P method is the most excellent in that distortion can be reduced. Further, the 2P method has a problem that the manufacturing time per substrate is long and is not suitable for mass production as compared with other methods, but has a great advantage that the capital investment is very small.

[0004]

On the other hand, the performance required for the UV curable resin used in the 2P method is that it has good adhesion to the substrate, good releasability from the stamper, and a recording layer. Although it does not deteriorate, a resin that has excellent curability and does not deteriorate the recording layer tends to have relatively poor adhesion to the substrate. Therefore, as described in JP-A-1-302554, a method of improving the adhesiveness of the resin by using a primer is used, but the number of steps is increased, the yield is decreased, and the recording layer caused by the primer is caused. There was a problem such as deterioration of. Further, the amorphous polyolefin substrate excellent in birefringence and cost has the problem that the ultraviolet curable resin is repelled due to the small surface energy of the substrate and the adhesiveness with the ultraviolet curable resin is poor.

Therefore, an object of the present invention is to solve the above-mentioned problems, and to compare the substrate for an optical information recording medium in which the adhesion between the substrate and the ultraviolet curing resin is good, to the case where a primer is used, It is an object of the present invention to provide a method for manufacturing by reducing the number of steps, improving productivity, and improving yield.

Further, according to the present invention, an amorphous polyolefin substrate, which is birefringent and cost effective, is used, and a substrate for an optical information recording medium having good adhesion between the substrate and an ultraviolet curable resin is manufactured with high productivity. The purpose is to

[0007]

A method of manufacturing a substrate for an optical information recording medium according to the present invention uses a stamper having a guide groove and / or an uneven pattern corresponding to information, and the uneven pattern of the stamper is formed on a substrate. In a method of manufacturing a substrate for an optical information recording medium by transferring and forming using an ultraviolet curable resin, a discharge is generated in a gas atmosphere containing at least oxygen under atmospheric pressure or a pressure in the vicinity thereof, and the discharge And a step of treating the substrate with an active species such as excitation and ions generated by.

Further, the substrate for the optical information recording medium is characterized by being an amorphous polyolefin.

A discharge generating electrode is disposed in the vicinity of the substrate, and a high frequency voltage is applied to the discharge generating electrode to cause discharge in the space between the substrate and the discharge generating electrode. Is characterized by.

In addition, a high-frequency voltage is applied between the discharge generating electrode and the counter electrode to cause discharge, and at least oxygen gas is passed through the discharge space to generate excitation and active species such as ions to generate oxygen. It is characterized in that a gas flow containing active species is sprayed from the gas outlet to the substrate not exposed to the discharge.

Further, the discharge generating electrode for exposing the substrate to a discharge or the gas outlet for blowing a gas flow without exposing to the discharge has a size larger than that of the substrate.

It is characterized in that the substrate is cooled or heated.

The apparatus for producing a substrate for an optical information recording medium according to the present invention comprises a discharge generating electrode, a means for applying a high frequency voltage to the discharge generating electrode under atmospheric pressure or a pressure in the vicinity thereof, and at least oxygen. And a means for introducing a gas containing the gas into the vicinity of the discharge generating electrode.

Further, it is characterized in that at least means for cooling or heating the substrate is provided.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic view showing Embodiment 1 of the present invention.

The process is carried out under atmospheric pressure and therefore the atmosphere is air. A discharge generating electrode 3 electrically floated by an insulator 6 is mounted in a metal cover 2 installed on the ground. Helium gas and oxygen are caused to flow from the gas supply device 5 into the metal cover 2, and the atmosphere near the discharge generating electrode 3 and the amorphous polyolefin substrate 1 is replaced with the helium gas and oxygen. Next, when high-frequency power is applied from the high-frequency power source 4 to the discharge-generating electrode 3, the discharge-generating electrode 3 is discharged between the substrate 1 and the discharge portion 7 is formed. In the discharge part 7, various reactions such as gas dissociation, ionization, and excitation due to plasma exist, and molecular bonds on the surface of the substrate are broken and oxidized, so that the wettability and the adhesiveness of the ultraviolet curable resin are improved. Here, helium gas was used as the gas for causing the discharge, but argon gas may be used. Further, the metal cover 2 is not always necessary as a condition for causing discharge. Furthermore, the metal cover 2 does not have to be metal, and may be ceramic. Although amorphous polyolefin is used as the substrate 1, polycarbonate, acrylic, polyester, epoxy, glass or the like may be used.

After the above treatment is applied to the entire surface of the substrate 1,
A predetermined amount of ultraviolet curable resin is applied. As the ultraviolet curable resin, a prepolymer, an oligomer, a monomer or the like having an unsaturated bond in the molecule can be used. For example,
Unsaturated polyesters, acrylates such as epoxy acrylate, urethane acrylate, and polyether acrylate, and one or more methacrylates such as epoxy methacrylate, urethane methacrylate, polyether methacrylate, and polyester methacrylate, and an unsaturated bond in the molecule. A photopolymerizable monomer having, for example, dicyclopentenyl acrylate, 1,3-
A mixture of functional monomers such as butanediol acrylate, polyethylene glycol diacrylate, pentaerythritol triacrylate, and halogenated acetophenones, benzophenone, benzoin, benzoin ether, Michler's ketone, benzyl, benzyl dimethyl ketal, thioxanthones as polymerization initiators. A radical-generating compound such as is used as long as it can be easily peeled from the stamper in a cured state and has a good matching with the recording layer. Next, the substrate and the stamper are attached to each other, and when the ultraviolet curable resin spreads over the entire surface of the substrate, ultraviolet rays are irradiated for a predetermined time from the transparent substrate side to cure the ultraviolet curable resin. Next, the substrate is separated from the stamper together with the ultraviolet curable resin to obtain a substrate having an uneven pattern. No defects such as bubbles were observed in the substrate thus obtained, and the adhesion between the substrate and the UV curable resin was also good. No resin peeling occurred in the cross-cut tape peeling test. .

Comparative Example 1 A substrate having a concavo-convex pattern was obtained in the same manner as in Example 1 except for the step of plasma treatment on the amorphous polyolefin substrate under atmospheric pressure. However, the transfer residue of the ultraviolet curable resin was generated on the stamper, and it became necessary to clean the stamper.
Further, the ultraviolet curable resin which was cured and transferred onto the substrate was also peeled off by a cross-cut tape peeling test.

Comparative Example 2 A substrate having a concavo-convex pattern was obtained in the same manner as in Example 1 except for the step of plasma treatment on a polycarbonate substrate under atmospheric pressure. However, 50% of the UV curable resin cured on the substrate was peeled off by the cross-cut tape peeling test.

Comparative Example 3 A substrate having a concavo-convex pattern was obtained in the same manner as in Example 1 except that only helium gas was used as the discharge gas. However, the UV curable resin cured on the substrate is 80
% Peeled off.

(Embodiment 2) FIG. 2 is a schematic diagram showing Embodiment 2 of the present invention.

The metal cover 2 of the first embodiment is extended to the vicinity of the tip of the discharge generating electrode 3 and is used as a counter electrode 8 for generating discharge. Similarly to the above, when helium gas and oxygen are caused to flow from the gas supply device 5 into the metal cover 2 to replace the inside with helium gas and oxygen, and a high frequency voltage is applied from the high frequency power source 4 to the discharge generating electrode 3. A discharge is generated between the tip of the discharge generating electrode 3 and the counter electrode 8. In the discharge part 7, a part of the oxygen gas becomes active species such as ions and excited species, and from the gas outlet 9 arbitrarily determined by the shape of the counter electrode 8 which is the tip of the metal cover 2, The reactive gas stream 10 is blown out together with the helium gas. The substrate 1 is installed at a distance of 3 to 5 mm from the gas outlet 9. The surface of the substrate 1 reacts with active species such as oxygen ions and excited species in the reactive gas stream 10 blown out from the gas outlet 9 to cut the surface molecular bonds and oxidize, and thus the ultraviolet curable resin. The wettability and adhesiveness of are improved.

After the above processing is applied to the entire surface of the substrate 1,
A predetermined amount of ultraviolet curable resin is applied. Next, the substrate and the stamper are attached to each other, and when the ultraviolet curable resin spreads over the entire surface of the substrate, ultraviolet rays are irradiated for a predetermined time from the transparent substrate side to cure the ultraviolet curable resin. Next, the substrate is separated from the stamper together with the ultraviolet curable resin to obtain a substrate having an uneven pattern. No defects such as bubbles were observed in the substrate thus obtained, and the adhesion between the substrate and the UV curable resin was also good. No resin peeling occurred in the cross-cut tape peeling test. .

In Embodiments 1 and 2, the size of the discharge generating electrode 3 when the substrate 1 is exposed to a discharge or the size of the gas blowout port 9 when a gas flow is blown without being exposed to the discharge is The larger the better, the substrate 1
If it is larger, the processing can be performed in a batch, and the processing can be performed in a short time and the processing can be performed while the substrate 1 is fixed, so that the load on the apparatus can be reduced.

(Embodiment 3) FIG. 3 is a schematic diagram showing Embodiment 3 of the present invention.

A heating / cooling device 11 was used as a holder for the substrate 1. Depending on the conditions, the substrate 1 is discharged or radiant heat of the discharge generating electrode 3 may be 50 to 10 degrees Celsius.
It is heated to 0 degrees. When the substrate 1 is one that is easily warped by heat, such as amorphous polyolefin, polycarbonate, or acrylic, the substrate 1 can be processed while being cooled. A substrate having a concavo-convex pattern was obtained in the same manner as in Example 1 with and without cooling the amorphous polyolefin substrate. The warp angle of each substrate after processing is shown in FIG. The warp angle can be reduced by cooling.

When the substrate 1 is stable against heat, such as glass, it should be heated conversely. Heat accelerates the reaction because it is a process using a chemical reaction. In the experiment conducted by the present inventor, the processing speed was about three times or more at about 150 degrees as compared with the room temperature.

[0029]

As is apparent from the above description, according to the present invention, discharge is performed at atmospheric pressure to generate active species such as oxygen ions and excited species, thereby causing a reaction between them and the substrate. Since it is a method of improving the adhesion between the substrate and the ultraviolet curable resin, therefore, not only an aqueous system can be used, but also high-speed dry processing is possible, and it is simple and
In addition, the device cost is low.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing Embodiment 2 of the present invention.

FIG. 3 is a schematic diagram showing Embodiment 3 of the present invention.

FIG. 4 is an explanatory view of a warp angle according to a third embodiment of the present invention.

[Explanation of symbols]

 1 substrate 2 metal cover 3 discharge generation electrode 4 high frequency power supply 5 gas supply device 6 insulator 7 discharge part 8 counter electrode 9 gas outlet 10 reactive gas flow 11 heating and cooling device

Claims (8)

[Claims] 1. A substrate for an optical information recording medium is formed by using a stamper having a guide groove and / or a concave / convex pattern corresponding to information, and transferring the concave / convex pattern of the stamper onto the substrate by using an ultraviolet curable resin. In the manufacturing method, a step of causing a discharge in a gas atmosphere containing at least oxygen under atmospheric pressure or a pressure in the vicinity thereof, and treating the substrate with active species such as excitation and ions generated by the discharge. A method for manufacturing a substrate for an optical information recording medium, which comprises: 2. The method for producing a substrate for an optical information recording medium according to claim 1, wherein the substrate for the optical information recording medium is an amorphous polyolefin. 3. A discharge generating electrode is disposed in the vicinity of the substrate, and a high-frequency voltage is applied to the discharge generating electrode to cause discharge in the space between the substrate and the discharge generating electrode. The method for manufacturing a substrate for an optical information recording medium according to claim 1. 4. A high-frequency voltage is applied between the discharge-generating electrode and the counter electrode to cause discharge, and at least oxygen gas is passed through the discharge space to generate an active species such as excitation and ion, thereby generating oxygen. 2. The method for manufacturing a substrate for an optical information recording medium according to claim 1, wherein a gas flow containing seeds is sprayed from the gas outlet to the substrate not exposed to the discharge. 5. The electrode for discharge generation in the case where the substrate is exposed to a discharge, or the gas outlet for blowing a gas flow without being exposed to the discharge is made larger than the size of the substrate. 1. A method for manufacturing a substrate for an optical information recording medium according to 1. 6. The method for manufacturing a substrate for an optical information recording medium according to claim 3, wherein the substrate is cooled or heated. 7. The discharge generating electrode, a means for applying a high frequency voltage to the discharge generating electrode, and a gas containing at least oxygen are introduced near the discharge generating electrode under atmospheric pressure or a pressure in the vicinity thereof. And a means for manufacturing an optical information recording medium substrate. 8. The apparatus for manufacturing a substrate for an optical information recording medium according to claim 7, further comprising at least a means for cooling or heating the substrate.