JP2622880B2 - Manufacturing method of roll stamper - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a roll type stamper used for manufacturing a substrate for an optical information recording medium.

[Prior Art] Conventionally, the optical information recording medium substrate is manufactured by a method such as injection molding or compression molding. However, in this method, the flatness and smoothness of the substrate are not sufficient. Warpage and air bubbles are likely to occur,
For this reason, there is a problem that the detection of information by light is significantly inhibited. In order to avoid such problems, the temperature at the time of manufacture,
It is very difficult to determine pressure conditions, mold accuracy, and prevent the generation of air bubbles, and requires a large apparatus, resulting in enormous costs. Furthermore, in the compression molding, since the single-wafer processing is used, there is a problem that the post-process is complicated and productivity is poor.

On the other hand, plastic flat plates are easily manufactured without bubbles, and smooth and uniform plates are easily manufactured.Therefore, a method has been proposed in which a stamper is brought into close contact with the plastic flat plate to apply pressure and transfer irregularities. Applying pressure to the entire surface of the flat plate requires a very large pressure.

As a method to solve this, if the plastic sheet extruded from the extruder is passed between the forming roller and the pressing roller with the stamper in close contact, the unevenness of the stamper can be cut into the plastic sheet with a small pressure, and then If the center hole and the outer periphery are trimmed, an optical information recording medium substrate can be easily obtained with a small device. In this method, as a method of attaching a stamper to the mirror surface roller, one of the stampers is fixed to the roller by pressing with a screw,
There is a method of mechanically pulling the other and winding it around a roller while applying tension, and a method of fixing with an adhesive.

[Problems to be Solved by the Invention] However, in order to bring the roller and the stamper into close contact,
As mentioned above, the method of fixing one of the stampers to the roller by pressing it with a screw, mechanically pulling the other, winding it around the roller while applying tension, and fixing it is easy to create a gap between the roller and the stamper. Etc. had disadvantages. Further, there is a disadvantage that the heat conduction between the roller and the stamper becomes non-uniform due to the formed gap, so that the transfer of unevenness is not successful.

Further, a method of fixing between the roller and the stamper using an adhesive such as an epoxy resin can be considered. However, the stamper needs to be replaced because the unevenness of the stamper is deformed while being pushed by the extruded sheet. However, fixing with an adhesive requires replacement of the entire roller, resulting in poor productivity.

The present invention has been made in order to improve such disadvantages of the prior art, and can fix a stamper in close contact with the surface of a mirror roller without a gap without using an adhesive or the like. It is an object of the present invention to provide a method of manufacturing a roll-type stamper that can easily replace a stamper.

[Means for Solving the Problems] That is, the present invention relates to a method for manufacturing a roll-type stamper used for continuously producing a substrate for an optical information recording medium having an irregular preformat signal, the method comprising: The low melting point metal layer is sandwiched between the mirror-finished rollers and the stamper with the low melting point metal layer is sandwiched between the mirror rollers. A method for manufacturing a roll-type stamper, characterized in that the stamper is fixed to a mirror-finished roller while forming the stamper.

 Hereinafter, the present invention will be described in detail.

1 (a) and 1 (b) are process diagrams showing an example of a method for manufacturing a roller type stamper of the present invention. First, as shown in FIG. 1 (a), a stamper 13 having an uneven surface is formed.
Are laminated on a mirror-finished roller 11 with a low-melting-point metal layer 12 interposed therebetween. In this case, a low-melting-point metal layer 12 is preferably provided outside the mirror-finished roller 11. Since the roll stamper manufactured according to the present invention is used as a forming roller, it needs to be heated to a high temperature when forming a sheet. For example, in the case of polycarbonate, since the temperature is 120 to 150 ° C., the low melting point metal layer 12 needs to have a melting point higher than that, and such a metal as an alloy such as a solder alloy such as Sn.Pb.In. Is used. These low-melting metals change their composition according to the roller temperature.

As for the thickness of the low melting point metal layer, the thinner the layer, the better the heat conduction, the less uneven the thickness, and the superior surface flatness and durability. Therefore, the thickness of the low melting point metal layer is desirably 100 μm or less.

Next, a stamper 13 formed by electroforming and having irregularities adapted to the irregular preformat signal formed on the optical information recording medium substrate is provided on the outside of the low melting point metal layer 12 provided on the mirror surface roller 11. Deploy.

The stamper 13 can be made of an ordinary metal without any particular limitation, and among them, nickel is preferable.
If the thickness of the stamper is too large, the roller diameter must be increased, and the device becomes large. On the other hand, if the stamper is too thin, the stamper loses its stiffness and tends to break. Therefore, the thickness of the stamper is suitably 50 to 500 μm.

Next, as shown in FIG. 1 (b), pressure is applied from above the stamper 13 overlying the low melting point metal layer 12 while heating it to a temperature equal to or higher than the melting point of the low melting point metal with a heat roller 14. The stamper 13 is fixed in close contact with the mirror surface roller 11 while making the thickness of the stamper 12 uniform. Specifically, using a heat roller 14, one end of the stamper 13 is pressed against the low melting point metal layer 12 on the mirror surface roller 11, and heated to a temperature equal to or higher than the melting point of the low melting point metal layer 12 to melt the low melting point metal. While pressing the heating roller 14 at a constant pressure from the state shown in FIG. 2 (a) to the state shown in FIG. 2 (b), the stamper 13 is fixed to the mirror surface roller 11 to produce a roll type stamper.

At least one end of the stamper is temporarily fixed with a screw, a metal belt, an adhesive, a heat-shrinkable tube, or the like.

The roll type stamper manufactured by the method of the present invention,
The present invention can be used for continuously producing a substrate for an optical information recording medium having an irregular preformat signal.

Next, FIG. 2 is an explanatory view showing a state where irregularities are transferred to a plastic flat plate using a roll-type stamper manufactured according to the present invention. In the figure, 1 is an extruder, 2 is a thermoplastic resin sheet such as polycarbonate, 3
Is a roll-type stamper of the present invention, which is a molding roller, 4 and 5 are mirror-finished pressure rollers, and 6 is a take-off machine. The gap between the roll type stamper 3 and the pressing roller 4 and the gap between the roll type stamper 3 and the pressing roller 5 can be adjusted so that the irregularities of the roll type stamper 3 can be sufficiently transferred to the surface of the thermoplastic resin sheet 2. It has become. At that time, the thermoplastic resin sheet 2 extruded from the extruder 1 is softened, and the roll type stamper 3, the pressing roller 4 and the roll type stamper 3
Then, the unevenness of the roll type stamper 3 and the mirror surfaces of the pressure rollers 4 and 5 of the mirror surface are sequentially transferred to the thermoplastic resin sheet 2 and moved rightward in the drawing as shown by the arrow and transferred. Complete.

[Operation] In the method of manufacturing a roll-type stamper according to the present invention, a stamper having irregularities formed on its surface is stacked with a low-melting-point metal layer sandwiched between mirror-surface rollers. By applying pressure while heating as described above, and by fixing the stamper in close contact with the mirror surface roller while making the thickness of the low melting point metal layer uniform, the stamper can be in close contact with the mirror surface roller without any gap. Further, when removing the stamper, the roller can be easily removed by heating the roller to a temperature higher than the melting point of the low melting point metal.

[Example] Hereinafter, the present invention will be described more specifically with reference to examples.

Example 1 A roll-type stamper was prepared using a nickel stamper having a thickness of 80 μm as a stamper and a solder alloy having a melting point of 195 ° C. and a thickness of 10 μm as a low-melting metal. First, one end of the stamper is temporarily fixed on a mirror roller provided with a low-melting metal layer with a screw, and a heating roller is pressed from above and heated to 200 ° C., and the heating roller is melted while melting the solder alloy. ) To a state as shown in FIG. 1 (b) while rolling at a constant pressure, temporarily fixing the other end of the stamper with a screw, and then cooling as it is to produce a roll-type stamper. The space between the stamper and the mirror surface roller of the roll type stamper was filled with a solder alloy and there was no gap.

This roll-type stamper was heated to 140 ° C. and used as a forming roll in FIG. 2 to extrude a polycarbonate resin to prepare an optical disc substrate. At the molding temperature of the above resin, the solder alloy becomes softer and follows even if the stamper extends slightly, so the heat of the roller is evenly transmitted to the stamper,
The transferability of the irregularities of the stamper was good.

Example 2 A nickel stamper having a thickness of 150 μm was used as a stamper.
A roll-type stamper was prepared using a solder alloy having a melting point of 220 ° C. as a low-melting metal. First, one end of the stamper is temporarily fixed with an instant adhesive (SC55, manufactured by Sony Chemical Co., Ltd.) on a mirror roller provided with a low-melting metal layer, and a heating roller is pressed from above and heated to 230 ° C. Then, the heating roller was rolled while being pressed at a constant pressure from the state shown in FIG. 1 (a) to the state shown in FIG. 1 (b) while melting the solder alloy, and then cooled as it was to form a roller type stamper.

This roll-type stamper was heated to 140 ° C. and used as a forming roll in FIG. 2 to extrude a polycarbonate resin to prepare an optical disc substrate. There is no gap between the stamper and the mirror roller of the roll type stamper, the low-melting metal is attached to the entire surface, the heat transfer from the mirror roller to the stamper is good, and the transferability of the concave and convex pattern of the stamper is good. Was.

[Effects of the Invention] As described above, according to the present invention, a low-melting-point metal layer is provided between a stamper having irregularities on its surface and a mirror-finished roller, and is heated to a melting point of the low-melting-point metal or higher by a heat roller. By pressing the stamper and fixing the stamper to the mirror surface roller while making the thickness of the low melting point metal layer uniform, the stamper can be fixed in close contact with the surface of the mirror surface roller without any gap.
When a resin sheet is formed using the obtained roll-type stamper, the irregularities of the stamper can be satisfactorily transferred to the extruded sheet.

Further, there is an advantage that the replacement of the stamper can be easily performed by raising the temperature of the roller to the melting point of the low melting point metal or higher.

[Brief description of the drawings]

1 (a) and 1 (b) are process diagrams showing an example of a method for manufacturing a roll-type stamper of the present invention, and FIG. 2 is for an optical information recording medium using a roll-type stamper obtained by the method of the present invention. It is explanatory drawing which shows an example of the apparatus used for the manufacturing method of a board | substrate. DESCRIPTION OF SYMBOLS 1 ... Extruder 2 ... Thermoplastic resin sheet 3 ... Roll type stamper 4, 5 ... Pressure roller 6 ... Take-up machine 11 ... Mirror surface roller 12 ... Low melting point metal layer 13 ... Stamper 14 ... Heat roller

Claims (1)

(57) [Claims] 1. A method for manufacturing a roll-type stamper used for continuously producing an optical information recording medium substrate having an irregular preformat signal, wherein a stamper having irregularities on its surface is interposed between mirror-surface rollers. The low-melting metal layer is sandwiched and stacked, and pressurized while heating to a temperature equal to or higher than the melting point of the low-melting metal with a heat roller from above the stamper, and fixing the stamper to the mirror surface roller while making the thickness of the low-melting metal layer uniform. A method for manufacturing a roll-type stamper, comprising the steps of: