JPH085130B2 - Roller for molding substrate for optical recording medium, molding apparatus, molding method and optical recording medium - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a molding roller, a molding apparatus, a molding method, and an optical recording medium for a substrate for an optical recording medium that optically records and reproduces information.

[Prior Art] Conventionally, magnetic materials such as magnetic tapes and magnetic disks, and various semiconductor memories have been mainly used for recording various information. Such magnetic memory and semiconductor memory have the advantage that information can be written and read easily, but on the other hand, the contents of information can be easily tampered with,
There is also a problem that high-density recording cannot be performed. In order to solve such a problem, an optical information recording method using an optical recording medium has been proposed as a means for efficiently handling a wide variety of information, and an optical information recording carrier, a recording / reproducing method, a recording / reproducing apparatus for that purpose, and the like. Is proposed.

The optical recording medium as such an information recording carrier is generally an optical recording medium that volatilizes a part of the optical recording layer on the information recording carrier using a laser beam, causes a change in reflectance, or causes a deformation to produce an optical recording medium. Information is recorded or reproduced by the difference in the typical reflectance or transmittance. In this case, the so-called DRAW (Direct Read After Write; direc) that allows the optical recording layer to be "read directly after writing" without the need for development processing after writing information.
Since it is a t read after write medium, high density recording is possible and additional writing is possible, it is effective as a catalyst for recording and storing information.

FIG. 5 is a schematic sectional view of a conventional optical recording medium.
In FIG. 5, 21 is a transparent substrate, 22 is a track groove portion,
23 is an optical recording layer, 24 is a spacer / adhesive layer, and 25 is a protective layer. In FIG. 5, recording / reproducing of information is performed by optically writing and reading through the transparent substrate 21 and the track groove portion 22. At this time, it is configured such that the fine unevenness of the track groove portion 22 can be used to perform tracking by the phase difference of the laser light.

[Problems to be Solved by the Invention] In an optical recording medium as described above, particularly in a conventional video disc, audio disc, etc., as shown in FIG. 4, a thermoplastic resin 1 made of polyvinyl chloride (PVC) is used.
1 is introduced into the heating box 14 through the feed roller 13 and heated by the infrared lamp 15 for heating, and then the information is recorded by pressing between the molding roller 16 and the pressure roller 17 of the mold in which information is recorded. The preformat pattern is transferred, then cooled with a cooling blower 18 and molded with a die-cutting roller to obtain a molded disk 12. (JP-A-56-86
However, optical recording media such as optical discs have stricter characteristic values than audio discs, so if the heat conductivity of the stamper to be molded is poor, or if the distribution of the heating amount is uneven, the extrusion molding machine Since the resin extruded from the resin does not become information that has been sufficiently heated at the time of molding, fine patterns may not be transferred accurately, or the thickness of the substrate may become uneven within the surface of the disk. Is occurring. Further, the unevenness of the heating amount distribution of the stamper at the time of molding has a problem that when polycarbonate or the like is used as the resin, the birefringence becomes uneven and the quality deteriorates.

Therefore, a stamper for molding a resin is required to have good flatness, good thermal conductivity, and little unevenness in thermal conductivity. For example, a thick stamper increases rigidity. As a result, not only is it difficult to wind the roller around a cylindrical roller, but also the thermal conductivity deteriorates.

In addition, when sticking the stamper, if the stamper is simply wrapped around the roller, or if it is simply stuck with an adhesive, the thermal conductivity of the roller and the stamper deteriorates, and uneven distribution of the heating amount of the stamper causes uneven light distribution. It is not enough for continuous production of recording media. In particular, when air enters between the stamper and the roller, irregularities are formed on the surface of the stamper, and the irregularities are transferred to the resin to deteriorate the quality of the substrate of the optical recording medium.

The present invention has been made for the purpose of solving the above-mentioned problems, and by interposing a mixture of an adhesive and powder particles of a metal or a metal compound between the roller and the stamper, the thermal conductivity is improved. It is an object of the present invention to provide a molding roller for a substrate for an optical recording medium, which has good heat distribution and a uniform heating amount distribution, a molding apparatus using the same, a molding method, and an optical recording medium.

[Means for Solving the Problems] That is, the present invention comprises a roller and a thin stamper fixed to the surface of the roller, and transfers the uneven pattern formed on the stamper to the surface of the resin sheet. In a molding roller for forming a preformatted optical recording medium substrate, the roller and the stamper are bonded by a mixture of an adhesive and a metal or metal compound powder particles uniformly mixed. A roller for molding a substrate for an optical recording medium.

Further, the present invention is a molding roller, a pressure roller provided to face the molding roller, and an extrusion molding machine for supplying a resin sheet between the pressure roller and the molding roller. Is a molding device for a substrate for an optical recording medium.

Further, the present invention, by molding the resin sheet extruded from the extrusion molding machine between the molding roller and the pressure roller provided so as to face the molding roller, preformatted light This is a molding method for forming a recording medium substrate.

The present invention also provides a preformat formed by molding a resin sheet extruded from an extrusion molding machine between the molding roller and a pressure roller provided opposite to the molding roller. An optical recording medium comprising an attached substrate and an optical recording layer formed on the substrate.

 Hereinafter, the present invention will be described in detail.

The present invention is an extrusion molding machine in which a resin is melted for an optical recording medium substrate that records and reproduces information by changing optical characteristics such as reflectance and transmittance by irradiation with a light beam such as a laser beam. It is a molding die used in a method for producing a transparent substrate with a preformat by simultaneously extruding from the same and forming a transparent substrate with a preformat. A thin stamper is formed on a roller for performing the molding, and an adhesive and a metal or metal compound are uniformly applied. It consists of a molding roller laminated with the mixture mixed in.

FIG. 1 is a cutaway sectional view showing an embodiment of a molding die for an optical recording medium substrate of the present invention, and FIG. 2 is a schematic view thereof. In the figure, in the mold for molding an optical recording medium substrate of the present invention, a roller 1 is provided with a stamper 2 via an adhesive layer 3 made of a mixture in which an adhesive and powder particles of a metal or a metal compound are uniformly mixed. It is composed of the molding roller 4 bonded together. A method of manufacturing a substrate for an optical recording medium using this molding roller 4 is, for example, as shown in FIG. 3, a resin sheet 8 extruded from an extrusion molding machine 5 is a molding roller in a softened state. 4 and the pressure roller 6 and between the molding roller 4 and the pressure roller 6 and pressed by the uneven surface of the molding roller 4 and the mirror surface of the pressure roller 6 to the surface of the resin sheet 8. The preformatted pattern of the stamper 2 or the uneven signal of information is sequentially transferred, and moves in the arrow X direction to complete the transfer.

The roller 1 in the present invention may be made of any material as long as it has high hardness and good thermal conductivity. For example, a metal such as iron or chrome ore, a metal alloy or a metal compound is used. be able to. The roller surface is processed by derusting, degreasing, removing water and polishing. As for the surface accuracy of the roller, any surface accuracy roller can be used as long as both the surface accuracy and the adhesive strength required for the surface of the molded substrate are satisfied. It is desirable that the accuracy be as good as, or better than, such surface accuracy. The surface accuracy of the preferable roller is 50 μm or less in pp.

In addition, if necessary, a hardened film such as titanium nitride on the surface,
It is possible to form a protective layer of silicon or the like, or it is possible to perform plating such as chrome plating.

The stamper 2 can be produced by a manufacturing method generally used for CDs (compact discs) and the like. Specifically, a resist is applied to a glass master, a pattern is exposed and developed, nickel is sputtered to form a film, and electroforming is performed to deposit nickel to a predetermined thickness. The third master (mother) and grandchild stamper may be created using the second master thus obtained as a father.

As the material of the stamper, a metal or a metal compound is used, and examples thereof include nickel, chromium, iron, silver or a compound thereof.

Further, the thickness of the stamper is the stamper 2 in the present invention.
In order to bond the resin to the roller 1 with the adhesive layer 3, it is preferable to use a thinner material than that generally used for injection. Therefore, the thickness of the stamper is 10 ~ 200
The thickness may be in the range of μm, preferably 20 to 150 μm.

The adhesive layer 3 is composed of a mixture of an adhesive, powder particles of a metal or a metal compound, and a curing agent, if necessary, in a uniform amount. As powder particles of metal or metal compound,
Powder particles of iron, aluminum, copper, lead or their oxides, nitrides, halides, chalcogenides and the like can be used. The diameter of the powder particles varies depending on the thickness of the adhesive layer, but is usually 1 to 50 μm, preferably 10 to 30 μm. As an adhesive, roller 1 and stamper 2
Any adhesive can be used as long as it can be joined and does not soften, deteriorate, or deform even at the molding temperature or generate gas. Preferred are thermosetting adhesives and reactive adhesives. Moreover, you may add a hardening agent as needed. The mixing ratio of the metal or metal compound powder and the adhesive depends on the type of adhesive or powder used, but the weight ratio of the metal or metal compound powder is 90% by weight or less and the adhesive is 10% by weight or more. It is good to If there are many powder particles, the heat conduction will be good, but the adhesive strength will be weak. Also, as the proportion of adhesive increases, the adhesive strength increases,
Heat conduction becomes poor. Considering that point, the more preferable composition ratio is 10 to 90% by weight of the metal or metal compound powder particles and 10 to 90% by weight of the adhesive as a composition. Moreover, you may add a hardening | curing agent and an additive as needed. The preferable addition amount is 1 to 10% by weight.

The molding roller of the present invention comprises a stamper on the surface of the above roller, which is laminated with a mixture of an adhesive and a powder of metal or a metal compound, and the thermal conductivity of the molding roller is 20 W / mK or more, preferably 20-100 W / mK
It is desirable to be in the range of.

In the present invention, the method of attaching the stamper 2 to the roller 1 is to apply an adhesive obtained by uniformly mixing metal or metal compound powder particles to the roller to a uniform thickness, and then attach the stamper thereon. As the thickness of the adhesive layer,
10 to 100 μm is preferable. Further, as a method of bonding, any ordinary method can be used, but for example, a method of sticking one end of the stamper and then sticking the stamper while crimping the roller can remove air between the roller and the stamper. You don't have to get involved. Other,
An adhesive may be applied to the stamper side. It is also possible to use both the fixing of the stamper by screwing both ends of the stamper together. In addition, as shown in FIG. 2, the roller 1 and the stamper 2 are
It is also possible to provide notches or uneven portions for alignment.

With a stamping molding roller of the present invention, after molding a resin sheet extruded from an extrusion molding machine, cutting into discs one by one, cleaning, recording layer film formation, laminating with a protective substrate, characteristic inspection, An optical recording medium can be obtained through a process such as packing.

[Operation] The molding roller for an optical recording medium substrate of the present invention is a molding roller for forming a preformatted optical recording medium substrate, and has a thin stamper on the surface of the roller, an adhesive and a powder of a metal or a metal compound. Since a molding roller formed by laminating a mixture of particles uniformly mixed is used, it is possible to obtain a molding roller having good thermal conductivity, uniform heating amount distribution, and good flatness. .

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

Example 1 As shown in FIG. 3, on an iron roller having a roller diameter of 350 mmφ, 80% by weight of iron powder particles having a particle diameter of 20 μm, 18% by weight of an epoxy resin (manufactured by Nozawa Chemical, Diamond Bond 2000S),
An adhesive obtained by uniformly mixing 2% by weight of diethylenetriamine (Kanto Chemical Co., Inc.) as a curing agent was uniformly applied with a roller to a thickness of 50 μm. From above, a stamper made of nickel electroforming having a thickness of 90 μm was attached in order from one end to the outer peripheral direction of the roller. The thermal conductivity after the adhesive was cured was 50 W / mK. This molding roller is attached to an extrusion molding machine (Hitachi Zosen, SHT90-32DVG), and 2.3m
Polycarbonate (K-1285, manufactured by Teijin Kasei) at a die temperature of 250 ° C and a roller temperature of 150 ° C at a speed of / min.
It was extruded to a thickness of 1.2 mm.

When the substrate subjected to the extrusion molding was measured, the unevenness in the thickness was 50 μm at the maximum, which was sufficiently small. The value of birefringence was 20 nm in a single pass, and there was little variation. The surface run-out amount was 50 μm in pp, which was sufficiently small. The transfer rate of the pre-format pattern formed on the stamper was 97% or more in depth.

This substrate was cut into 86 mmφ and the optical recording material represented by the following structural formula [I] was solvent coated to form an optical recording layer having a thickness of 1000 Å.

A 0.3 mm thick polycarbonate (Panlite 251 manufactured by Teijin Kasei) was cut into 86 mmφ on the protective substrate, and adhered with an air gap of 0.3 mm to obtain an optical disk. When the recording / playback of the obtained optical disc was performed, the disc rotation speed was 1800 rpm, the writing frequency was 3 MHz, and the writing power was
At 6 mW and read power of 0.5 mW, the C / N ratio was 50 dB.

Example 2 In the same manner as in Example 1, 70% by weight of alumina powder having a particle diameter of 20 μm and epoxy resin (Diabond 2000S manufactured by Nozawa Chemical Co., Ltd.) were used on an iron roller having a roller diameter of 350 mmφ.
Using a roller, apply an adhesive that mixes 8% by weight and 2% by weight of diethylenetriamine (Kanto Kagaku) as a curing agent uniformly.
Uniformly applied to a thickness of μm, and the same as in Example 1.
An 81 μm nickel stamper was attached in order. The thermal conductivity after the adhesive was cured was 39 W / mK. This roller was attached to the same extrusion molding machine as in Example 1, and the same resin as in Example 1 was extrusion molded under the same conditions.

When the substrate subjected to the extrusion molding was measured, the unevenness in the thickness was 50 μm at the maximum, which was sufficiently small. The value of birefringence was 20 nm in a single pass, and the variation was small.
The surface run-out amount was 50 μm in pp, which was sufficiently small. The transfer rate of the preformat pattern formed on the stamper was 98% or more in depth.

Similar to Example 1, this substrate was cut into 86 mmφ to form an optical recording layer, and then a protective substrate was adhered to obtain an optical disc. When the recording / reproducing of the obtained optical disc was performed, the disc rotation speed was 1800 rpm, the writing frequency was 3 MHz, the writing power was 6 mW, and the reading power was 0.5 mW, and the C / N ratio was 50 dB.
Met.

Example 3 In the same manner as in Example 1, on an iron roller having a roller diameter of 350 mmφ, 75% by weight of copper powder particles having a particle diameter of 20 μm, epoxy resin (manufactured by Nozawa Chemical, Diamond Bond 2000S) 23% by weight, and diethylenetriamine as a curing agent were used. (Kanto Chemical Co., Ltd.) 2% by weight of an evenly mixed adhesive with a roller of 60 μm
To a thickness of 85 μm as in Example 1.
The nickel stampers were attached in order. The thermal conductivity after the adhesive was cured was 80 W / mK. This roller was attached to the same extrusion molding machine as in Example 1, and the same resin as in Example 1 was extrusion molded under the same conditions.

When the substrate subjected to the extrusion molding was measured, the unevenness in the thickness was 50 μm at the maximum, which was sufficiently small. The value of birefringence was 20 nm in a single pass, and the variation was small.
The surface run-out amount was 50 μm in pp, which was sufficiently small. The transfer rate of the preformat pattern formed on the stamper was 98% or more in depth.

This substrate was cut into 86 mmφ in the same manner as in Example 1 to form an optical recording layer, and then a protective substrate was adhered to obtain an optical disc. When the recording / playback of the obtained optical disk was performed, the disk rotation speed was 1800 rpm, the writing frequency was 3 MHz, the writing power was 6 mW, the reading power was 0.5 mW, and the C / N ratio was 50 dB.
Met.

Comparative Example 1 In the same manner as in Example 1, an iron roller having a roller diameter of 350 mmφ was charged with epoxy resin (Diabond 2000S manufactured by Nozawa Chemical) and diethylenetriamine (Kanto Kagaku) 14:
The mixture was uniformly mixed in a weight ratio of 1 and applied uniformly to a thickness of 50 μm, and the same 90 μm thick nickel stamper as in Example 1 was laminated in the same manner as in Example 1. The thermal conductivity after the adhesive was cured was 15 W / mK. This roller is used in Example 1
The same resin as in Example 1 was extruded and molded under the same conditions.

When the extrusion-molded substrate was measured, the thickness unevenness was 90 μm, which was larger than that in Example 1. The birefringence is 60-190nm in a single pass, and the value is large and the difference by location is large. The amount of surface deflection was 100 μm in pp, which was larger than that in Example 1. These values are the values of Example 1.
Since it was significantly inferior to ~ 3, it was impossible to measure the recording / reproducing characteristics.

[Effects of the Invention] As described above, according to the molding roller of the present invention, since the thermal conductivity of the roller is good, the transferability of the pattern is good, and the distribution of the heating amount is uniform, so that the molding roller is molded. Substrate thickness unevenness and birefringence unevenness are small and surface accuracy is good.
There is an effect that a substrate for an optical recording medium can be provided.

[Brief description of drawings]

FIG. 1 is a cutaway sectional view showing an embodiment of a molding roller for a substrate for an optical recording medium of the present invention, and FIG. 2 is a schematic view thereof.
FIG. 3 is a schematic view showing a method for manufacturing a substrate for an optical recording medium using the molding roller of the present invention, FIG. 4 is a schematic view showing a method for manufacturing a conventional substrate for an optical recording medium, and FIG. It is sectional drawing which shows the conventional optical recording medium. 1 ... Roller, 2 ... Stamper 3 ... Adhesive layer, 4 ... Molding roller 5 ... Extrusion molding machine, 6 ... Pressure roller 7 ... Take-up roller, 8 ... Resin sheet 11 ... Thermoplastic Resin 12 …… Molded disk 13 …… Feed roller, 14 …… Heating box 15 …… Heating infrared lamp, 16 …… Molding roller 17 …… Pressure roller, 18 …… Cooling blower 19 …… Die cutting Roller, 21 …… Transparent substrate 22 …… Track groove, 23 …… Optical recording layer 24 …… Spacer / adhesive layer, 25 …… Protective substrate

Claims (6)

[Claims] 1. A substrate for a preformatted optical recording medium, comprising a roller and a thin stamper fixed to the surface of the roller, and transferring the uneven pattern formed on the stamper onto the surface of a resin sheet. A molding roller for forming an optical recording medium substrate, wherein the roller and the stamper are bonded together with a mixture in which an adhesive and a metal or metal compound powder are uniformly mixed. 2. The roller for molding a substrate for an optical recording medium according to claim 1, which has a thermal conductivity of 20 W / mK or more. 3. The roller for molding an optical recording medium substrate according to claim 1, wherein the stamper is made of a metal or a metal compound and has a thickness of 10 to 20 μm. 4. The molding roller according to claim 1, a pressure roller provided so as to face the molding roller, and a resin sheet is supplied between the pressure roller and the molding roller. A device for molding a substrate for an optical recording medium, which comprises an extrusion molding machine. 5. A resin sheet extruded from an extrusion molding machine is passed between the molding roller according to claim 1 and a pressure roller provided so as to face the molding roller, thereby molding. A molding method for forming a preformatted optical recording medium substrate. 6. Formed by passing a resin sheet extruded from an extrusion molding machine between the molding roller according to claim 1 and a pressure roller provided opposite to the molding roller. Recording medium comprising a pre-formatted substrate and an optical recording layer formed on the substrate.