JP2656628B2 - Method for manufacturing substrate of optical information recording medium and method for manufacturing roller used in the method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a substrate of an optical information recording medium for recording and reproducing using light.

[Conventional technology]

The substrate of the optical information recording medium usually has a fine uneven pattern for guide grooves, address signals, and the like. As a method of manufacturing such a substrate, an injection molding method, a compression molding method, and the like are generally performed. However, production efficiency is not yet sufficient in these methods. In addition, since the concavo-convex molding is performed under a high temperature and a high pressure, a mold having a fine concavo-convex shape is apt to be deteriorated, and the flatness, smoothness, warpage, mixing of bubbles, etc. of the substrate are not yet sufficient.

Therefore, a method has been proposed in which a thin plate (hereinafter, referred to as a stamper) having an uneven shape corresponding to a recording signal is closely attached to a plastic flat plate and pressure is applied to transfer the unevenness. In this method, it is not so difficult to previously form a plastic flat plate having good smoothness without air bubbles. However, in this method, since pressure is applied to the entire stamper at the time of molding, pressure must be applied with a very strong force. Further, continuation of the manufacturing process is not yet sufficient.

Therefore, a method of continuously manufacturing a substrate using an extruder and a roller (hereinafter, referred to as an extrusion method) has been studied. If this extrusion molding method can be performed well, the continuation of the process becomes easy, and the mold for unevenness on the roller to be used is not exposed to high temperature and high pressure, so that the mold is hardly deteriorated, and Therefore, it is expected that it is sufficient to apply pressure with a relatively weak force.

[Problems to be solved by the invention]

However, the following problems remain in the extrusion molding method.

One of the problems is that it is difficult to form a highly accurate uneven pattern. The accuracy of the concavo-convex pattern is very important in an optical information recording medium, and if the accuracy is low, the function of the optical information recording medium is significantly impaired.

Another problem is that maintenance in manufacturing is very complicated. For example, in order to form a highly accurate uneven pattern, it is usual to firmly fix the rotating shaft of the roller in order to keep the dimensional accuracy, temperature accuracy and the like constant. Therefore,
If dirt or scratches are formed on the uneven surface of the roller, it may be difficult to replace the roller.

The present invention has been made to solve such a problem and achieve the practical use of an extrusion molding method. That is, a main object of the present invention is to provide a method for manufacturing a substrate of an optical information recording medium, which can form a highly accurate concave and convex pattern, facilitates maintenance in manufacturing, has good production efficiency, and is unlikely to deteriorate a mold. To provide.

[Means for solving the problem]

In the present invention, the substrate material is extruded into a sheet by an extruder, and the sheet-shaped extruded material is pressed by a roller having a concavo-convex shape corresponding to a recording signal, thereby transferring the irregularity shape to the sheet-shaped extruded material. In the method for manufacturing a substrate of an optical information recording medium including a step, the roller, on the peripheral wall of the cylindrical member, via an adhesive, a thin plate formed with irregularities corresponding to signal recording, from above the thin plate A method for manufacturing a substrate for an optical information recording medium, comprising a roller manufactured by a method having a step of fixing with a heat-shrinkable tube, curing the adhesive, and removing the heat-shrinkable tube from a thin plate, and This is a method for manufacturing a roller for manufacturing a substrate of the optical information recording medium.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Example 1 Production of Stamper: First, as shown in FIG.
A master film 3 is obtained by forming a resist film 2 having a uniform thickness thereon. Next, as shown in FIG. 2, the resist film 2 is irradiated with a laser beam 4 modulated by a predetermined information signal or tracking signal while rotating the master 3. Next, the exposed or unexposed portions are removed (development processing).
By doing so, a groove corresponding to the information signal is formed. Next, as shown in FIG. 3, a metal conductive film 6 of Ni or the like is formed on the surface by a sputtering method or the like. Next, as shown in FIG. 4, using the metal conductive film 6 as a cathode,
The electroformed film 7 is formed by electroforming the stamper base material to a predetermined thickness. Next, as shown in FIG. 5, the electroformed film 7 is released together with the metal conductive film 6 to obtain a desired stamper 8 having an inverted concavo-convex pattern.

If the stamper 8 is too thick, the adhesion to the roller deteriorates. If the stamper 8 is too thin, it deforms when tension is applied. For example, in the case of a stamper manufactured by Ni electroforming, the thickness is 0.03 to 0.50 mm
About 0.05 to 0.03 mm is desirable.

As shown in FIG. 6, an adhesive is provided on the peripheral wall of the cylindrical member 9.
The stamper 8 produced as described above is fixed by a heat shrink tube 17 via 16. In this state, the adhesive 16 is cured, and then the heat-shrinkable tube 17 is removed to obtain a roller for manufacturing a substrate for an optical information recording medium. The peripheral wall of the cylindrical member 9 is desirably a mirror surface.

In this embodiment, the stamper 8 can be provided around the roller,
Any material may be used as long as it is a thin plate capable of forming desired irregularities on the substrate, and the material, size, and the like are not particularly limited. However,
Nickel is generally used as the material. On the other hand, if the stamper 8 is too thick, it will be difficult to provide a periphery around the cylindrical member later. On the other hand, if it is too thin, the stamper 8 will be easily broken. From the above point, the thickness of the stamper is preferably about 30 to 500 μm, and more preferably about 50 to 300 μm.

In the present embodiment, for example, when polycarbonate is used as the substrate material, the roller temperature at the time of forming the unevenness is 12
Since the temperature is about 0 ° C. to 150 ° C., it is desirable to use an adhesive having heat resistance so as not to be adversely affected even at such a temperature. Examples of such an adhesive include an epoxy resin-based adhesive and a cyanoacrylate-based adhesive. It is desirable that the thickness of the adhesive 14 be appropriately thin in terms of adhesive strength, unevenness, flatness, durability, and the like. Although the optimum value varies depending on various conditions, the thickness of the adhesive 16 is preferably 50 μm or less.

In the present embodiment, first, it is desirable to heat at a temperature at which the heat-shrinkable tube 17 shrinks appropriately and the adhesive 16 has fluidity. The heating temperature is 80 ℃ ~ 120 ℃
The degree is appropriate. When such heating is performed, the stamper 8 is uniformly pushed inward by the contracting force of the heat-shrinkable tube 17, and the adhesive 16 is thereby uniformly uniform as a result, so that the stamper 8 is not deformed. It is fixed uniformly.

After the fixing state is good as described above, heating is performed at a temperature at which the adhesive 16 hardens. 120 ° C to 150 as described above
Curing temperature of adhesive with moderate heat resistance is about 20 ℃
0 ° C or higher. After the adhesive has sufficiently hardened, the heat-shrinkable tube 17 is removed, and the roller is used for manufacturing a substrate of an optical information recording medium.

The heat-shrinkable tube 17 is desirably soft so as not to damage the stamper, and desirably uses polytetrafluoroethylene (PTFE) or the like. However, the heat-shrinkable tube 17 is not limited to PTFE as long as it has the appropriate heat-shrinking action. For example,
Other than PTFE, 4-6 fluorinated resin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin and the like can be used.

In the roller made of a heat-shrinkable tube as in this embodiment, the thickness of the adhesive 16 between the stampers is also uniform. Therefore, the roller is a roller having high-precision irregularities and, therefore, can form high-accuracy irregularities on a substrate, and thus is a roller very suitable for manufacturing a substrate of an optical information recording medium.

〔The invention's effect〕

As described above, the method for manufacturing a substrate of an optical information recording medium according to the present invention is an extrusion molding method in which continuity is easy, production efficiency is good, and a mold is hardly deteriorated, and a highly accurate uneven pattern is formed. This is a manufacturing method that can be performed and maintenance is easy.

Further, the roller used in the method for manufacturing a substrate of an optical information recording medium of the present invention is a very suitable roller capable of achieving practical use of the extrusion molding method.

Further, the method of manufacturing a roller for manufacturing a substrate of an optical information recording medium according to the present invention is a method capable of forming the unevenness of the roller used in the extrusion molding method with very high precision and goodness.

[Brief description of the drawings]

1 to 5 are views showing a stamper manufacturing process by an electroforming method, and FIG. 6 is a schematic cross-sectional view showing one process in manufacturing the roller of the first embodiment. DESCRIPTION OF SYMBOLS 1 ... Base material for master 2 ... Resist film 3 ... Master 4 ... Laser light 6 ... Metal conductive film 7 ... Electroformed film 8 ... Stamper 9 ... Cylindrical member 16 ... Adhesive 17 …… Heat shrink tube

Claims (2)

(57) [Claims] An extruder extrudes a substrate material into a sheet and presses the sheet extrudate with a roller having a concavo-convex shape corresponding to a recording signal, thereby transferring the concavo-convex shape to the sheet-like extrudate. In the method for manufacturing a substrate of an optical information recording medium, the method comprises the steps of: forming a thin plate on which an uneven shape corresponding to signal recording is formed on a peripheral wall of a cylindrical member through an adhesive on the thin plate; A method of manufacturing a substrate for an optical information recording medium, comprising: a roller having a process of fixing the adhesive with a heat-shrinkable tube, curing the adhesive, and removing the heat-shrinkable tube from a thin plate. 2. A thin plate having irregularities corresponding to signal recording formed on the peripheral wall of a cylindrical member via an adhesive is fixed from above the thin plate with a heat-shrinkable tube, and the adhesive is cured. A method of manufacturing a substrate manufacturing roller for an optical information recording medium, comprising a step of removing the heat-shrinkable tube from a thin plate.