JPH02155629A - Mold for molding substrate for optical recording medium - Google Patents

Abstract

PURPOSE:To improve heat conductivity and to uniformize the distribution of heating quantity by interposing a mixture prepared by uniformly mixing an adhesive and particles of a metal or a metal compound between a roller and a stamper. CONSTITUTION:A molding roller 4 is formed by adhering a stamper 2 to a roller 1 through an adhesive layer 3 composed of a mixture prepared by uniformly mixing an adhesive with particles of a metal or a metal compound. For example, the resin sheet 8 extruded from an extrusion molding machine 5 is inserted between the molding roller 4 and a press roller 6 in a softened state and pressed by the uneven surface of the molding roller 4 and the mirror surface of the press roller 6 to successively transfer the uneven signal of the preformat pattern or data of the stamper to the surface of the resin sheet 8 and the resin sheet is moved in the direction shown by an arrow X to complete transfer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mold for molding 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, various semiconductor memories, and the like have been mainly used to record various types of information. Such magnetic memories and semiconductor memories have the advantage that information can be written and read easily, but on the other hand, there are problems in that the information content can be easily tampered with and high-density recording cannot be performed. In order to solve these problems, an optical information recording method using an optical recording medium has been proposed as a means to efficiently handle a wide variety of information, and optical information recording carriers, recording/reproducing methods, recording/reproducing devices, etc. for this purpose have been proposed. is proposed.

Such an optical recording medium as an information recording carrier is generally prepared by using a laser beam to evaporate a part of the optical recording layer on the information recording carrier, to cause a change in reflectance, or to cause deformation. Information is recorded or reproduced based on differences in optical reflectance and transmittance. In this case, the optical recording layer is a so-called [I
RA★ (Direct Read After Write; di
It is an effective medium for recording and storing information because it is capable of high-density recording and additional writing is possible.

FIG. 5 is a schematic cross-sectional view of a conventional optical recording medium. In FIG. 5, 21 is a transparent substrate, 22 is a track groove, 23 is an optical recording layer, 24 is a spacer/adhesive layer, and 25 is a protective layer. In FIG. 5, information is recorded and read by optically writing and reading through a transparent substrate 21 and a track groove 22. At this time, the minute irregularities of the track groove 22 are used to generate a phase difference between laser beams. It is configured to allow tracking.

[Problem to be solved by the invention] In optical recording media such as those described above, particularly in conventional video discs, audio discs, etc., as shown in FIG. 11 is introduced into the heating box 14 through the feed roller 13 and heated with the heating infrared lamp 15, and then the molding roller 16 and pressure roller 1 of the mold on which information is recorded are introduced.
7 to transfer the information or preformat pattern by heating and pressing, and then cooling with a cooling blower 18,
A molded disk 12 is obtained by molding using a die-cutting roller.

(Japanese Unexamined Patent Publication No. 56-86721) However, the characteristic values of optical recording media such as optical discs are more severe than those of audio discs, so the heat conduction of the molded stand bar may be poor or the distribution of the amount of heating may be uneven. If it is uniform, the resin extruded from the extrusion molding machine may not be heated enough during molding.
This results in problems such as fine patterns not being transferred accurately and the thickness of the substrate becoming uneven within the surface of the disk. Furthermore, uneven distribution of the heating amount of the stun bar during molding causes uneven birefringence when polycarbonate or the like is used as the resin, resulting in a problem in that quality deteriorates.

For this reason, the stambar for molding resin is required to have good surface workability, good thermal conductivity, and little unevenness in thermal conductivity.
If it is too thick, it will not only be more rigid and difficult to wrap around a cylindrical roller, but also have poor thermal conductivity.

In addition, when attaching the stand bar, if you simply wrap the stand bar around the roller or simply attach it with adhesive, the thermal conductivity between the roller and the stand bar will deteriorate.
Further, since the distribution of the heating amount of the stand bar becomes uneven, the amount of heat is not sufficient to continuously produce optical recording media. especially,
If air gets between the stand bar and the roller, the stand bar
The problem is that the surface of the optical recording medium becomes uneven, and the unevenness is transferred to the resin, deteriorating the quality of the substrate of the optical recording medium.

The present invention has been made to solve the above problems, and by interposing a mixture of adhesive and powder of metal or metal compound uniformly between the roller and the stand bar, thermal conductivity can be improved. It is an object of the present invention to provide a mold for molding a substrate for an optical recording medium, which has good hardness and uniform distribution of the amount of addition.

[Means for Solving the Problems] That is, the present invention passes a resin sheet extruded from an extrusion molding machine between a molding roller and a pressure roller of a mold having a fixed stub bar, and molds the resin sheet with a preformat. In a mold for forming a substrate for an optical recording medium, the molding roller is formed by pasting a thin stamper on the surface of the roller with a mixture of an adhesive and a uniform mixture of metal or metal compound powder. A mold for molding a substrate for an optical recording medium, characterized by:

The present invention will be explained in detail below.

The present invention uses an extrusion molding machine that melts a resin to create a substrate for an optical recording medium on which information is recorded and reproduced by changing optical properties such as reflectance and transmittance by irradiation with a light beam such as a laser beam. This is a molding mold used in a manufacturing method in which a transparent substrate with a preformat is formed by extrusion from a transparent substrate and molding at the same time. It consists of forming rollers bonded together with a uniformly mixed mixture.

FIG. 1 is a cutaway sectional view showing an embodiment of a mold for forming an optical recording medium substrate of the present invention, and FIG. 2 is a schematic diagram thereof. In the figure, the mold for molding a substrate for an optical recording medium of the present invention is such that a stamper 2 applies an adhesive layer 3 made of a uniform mixture of powder particles of an adhesive and a metal or a metal compound to a roller 1. It is made up of molding rollers 4 that are bonded together with a molding roller 4 interposed therebetween. In the method of manufacturing an optical recording medium substrate using this molding roller 4, for example, as shown in FIG. 4 and the pressure roller 6, and between the molding roller 4 and the pressure roller 6, and is pressed by the uneven surface of the molding roller 4 and the mirror surface of the pressure roller 6, and is pressed onto the surface of the resin sheet 8. The preformat pattern of the stamper 2 or the concave and convex signals of the information are sequentially transferred, and the stamper moves in the direction of the arrow X to complete the transfer.

The roller l in the present invention can be made of any material as long as it has high hardness and good thermal conductivity; for example, metals such as iron and chromite, metal alloys,
Metal compounds and the like can be used. Processing of the roller surface involves derusting, degreasing, removing moisture, and polishing. As long as the surface precision of the roller satisfies both the surface precision and adhesive strength required for the surface of the substrate to be molded, any roller with any surface precision can be used. A precision as good as or better than the required surface precision is desired. The surface precision of the roller is preferably 50 or less in pp.

Furthermore, if necessary, a hardened film such as titanium nitride or a protective layer such as silicon may be formed on the surface, or plating such as chrome plating may be applied.

The stamper 2 can be manufactured by a manufacturing method generally used for CDs (compact discs) and the like. Specifically, a resist is applied to a glass master disk, a pattern is exposed and developed, a nickel film is formed by sputtering, and nickel is deposited to a predetermined thickness by electroforming. Using the second master disc obtained in this way as a father, a third master disc (mother) and a grandchild stand bar may be created.

As the material of the stamper, a metal or a metal compound is used, such as nickel or chromium.

Examples include iron, silver, and compounds thereof.

Further, the thickness of the stamper is preferably thinner than that generally used for injection in order to bond the stamper 2 to the roller 1 with the adhesive layer 3 in the present invention. Therefore, the thickness of the stamper is 10 to 20 mm.
It may be within the range of 0 gm, preferably 20 to 150 p.
m or desirable.

The adhesive layer 3 is made of a mixture of an adhesive, powder particles of a metal or metal compound, and, if necessary, a fixed amount of a hardening agent. As the metal or metal compound powder, powder of iron, aluminum, copper, lead, or their oxides, nitrides, halides, chalcogenides, etc. can be used.

The diameter of the powder particles varies depending on the thickness of the adhesive layer, and is usually 1 to 50.
A pot with a capacity of 10 to 30 pots is desirable.

The adhesive used to bond roller 1 and stamper 2 softens or deteriorates even at molding temperatures.

Any adhesive can be used as long as it does not deform or emit gas. Preferred examples include thermosetting adhesives and reactive adhesives. Further, a curing agent may be added if necessary. The mixing ratio of metal or metal compound powder and adhesive depends on the type of adhesive and powder used, but in terms of weight ratio, metal or metal compound powder should be 90% by weight or less, and adhesive should be 10% or more by weight. It's good to do it. If there are too many powder particles, the heat conduction will be better or the adhesive force will be weaker. Furthermore, as the ratio of adhesive increases, the adhesive strength increases, but the heat conduction deteriorates. Considering this point, a more preferable composition ratio is that the powder of the metal or metal compound is 10 to 90% by weight, and the adhesive is 10 to 90% by weight. Further, a curing agent or an additive may be added as necessary. The preferable addition amount is 1 by weight.
~10%.

The molding roller of the molding mold of the present invention is made by laminating a stambar on the surface of the above-mentioned roller with a mixture of an adhesive and a uniform mixture of metal or metal compound powder particles.
The thermal conductivity of the forming roller is desirably in the range of 20 W/m or less, preferably 20 to 10091/m.

The method of bonding the roller l of the stand bar 2 of the molding die of the present invention is to apply an adhesive uniformly mixed with metal or metal compound powder to the roller to a uniform thickness, and then
Attach the stand bar to the paper. The thickness of the adhesive layer is preferably 10 to 100 l. Also, can any of the usual methods be used for bonding? For example, can one end of the stub bar be affixed and then the stambar be affixed while pressing the rollers? There is no need to entrain air.

Alternatively, an adhesive may be applied to the stand bar side.

It is fully possible to fix the stand bar by screwing both ends of the stand bar together. Further, as shown in FIG. 2, the roller 1 and the stand bar 2 may be provided with a notch or an uneven portion in a part thereof for alignment.

After molding the resin sheet extruded from the extrusion molding machine using a molding mold consisting of a roller with a stand bar of the present invention, it is cut into discs one by one, washed, deposited with a recording layer, and bonded with a protective substrate. An optical recording medium can be obtained through processes such as bonding, property testing, and packaging. [Function] The mold for molding a substrate for an optical recording medium of the present invention can form a substrate for an optical recording medium with a free format. As a mold for molding, we use a molding roller with a thin stambar attached to the surface of the roller with a uniform mixture of powder particles of adhesive and metal or metal compound, so the thermal conductivity is low. It is possible to obtain a mold for molding which has a good temperature, is uniform by the amount of heating, and has good flatness.

[Example] Hereinafter, the present invention will be explained in more detail by showing examples.

Example 1 As shown in Figure 3, an iron roller with a roller diameter of 350 mm was coated with 80 wt.
) 18% by weight, diethylenetriamine (
Kanto Kagaku) 2% by weight of adhesive was evenly mixed with a roller to a thickness of 50gm9.A 90Bm thick nickel electroformed stand bar was then applied from one end of the roller to a thickness of 50gm. They were pasted in order in the direction of the outer circumference. The thermal conductivity of the adhesive after curing was 50 W/■. This molding roller is extruded using an extrusion molding machine (manufactured by []Tachizosen, 5
HT90-32DVG) Attach 2. :li
/min speed, die temperature 250℃, roller temperature 1
Under conditions of 50°C, polycarbonate (manufactured by Ondai Kasei, K
-1285) was extrusion molded to a thickness of 1.2 ml and 1 m.

When the extrusion molded substrate was measured, the maximum thickness unevenness was 50 g+s, which was sufficiently small. The value of birefringence was 2OnIl in a single pass, and there was little variation. The amount of surface runout was 50 gm pp, which was sufficiently small.

The transfer rate of the preformat pattern formed on the stanbar was 97% or more in terms of depth.

This substrate was cut into 86 mmφ and the following structural formula [I]
An optical recording layer having a thickness of 1,000 layers was formed by coating the optical recording material shown in the following with a solvent.

Structural formula [I] (C2H5)2N<γ + N (C2Hl)2
For the cpo4θ protection board, cut 0.31H polycarbonate (manufactured by Kijin Kasei, Panlite 251) to 86mmφ.
: An optical disc was obtained by adhering so as to have an air gap of 1 mm. When the obtained optical disk was recorded and reproduced, the rotation speed of the disk was 1800 rpm, the old frequency was 3 MI (z), the old power was 6 mW, the read power was 0.5 mW, and the C/N ratio was 50 dR.

Example 2 Using the same method as in Example 1, 70% by weight of alumina powder particles with a particle size of 20 gm were placed on an iron roller with a roller diameter of 350 mm.
, epoxy resin (manufactured by Nozawa Chemical, Diabon l"
An adhesive uniformly mixed with 2000S > 28th edition i% and diethylene 1 heliamine (Kanto Kagaku) 2 times M:% as a hardening agent was uniformly applied with a roller to a thickness of 50 doses, and as in Example 1. Similarly, the proverbial 2-Sokel stambar with a thickness of 81 μm was pasted in order. The thermal conductivity of the adhesive after curing was 39 W/mK. This roller was attached to the same extrusion molding machine as in Example 1, and extrusion molding was performed under the conditions of rotating the resin as in Example 1.

When the extrusion molded substrate was measured, the maximum thickness unevenness was 50 l, which was sufficiently small. The value of birefringence was 20 Hm in a single pass, and there was little variation. The amount of surface runout was 1 minute smaller at 50 l on p-p. The transfer rate of the preformat pattern formed on the stanbar was 98% or more in depth.

This substrate was cut into pieces of 86 mm in diameter to form an optical recording layer in the same manner as in Example, and then a protective substrate was adhered to obtain an optical disc. When I recorded and played back the optical disc that had been removed, the disc rotation speed was 1800 rpm, the old frequency was 3 MHz, the write power was 6 ai9t, the read power was 0.5 watts, and the C/N ratio was 5 [] dB. Ta.

Example 3 Same method as Example 1 C, roller diameter 350 φ
Particle size 20#1. Im copper powder 7
Using a roller, apply an adhesive uniformly mixed with 5% epoxy resin (Diabon L' 2000S, manufactured by Nozawa Chemical), 231% hardening agent, and 2% diethylenetriamine (Kanto Kagaku) by weight. As in Example 1, the thickness was 8.
'B and m nickel stump bars were pasted in order +j. Thermal conductivity (W) after the adhesive had hardened was 80★/lK. This roller was attached to the same extrusion molding machine as in Example 1, and extrusion molding was performed under the same conditions as in Example 1. Ta.

When the extrusion molded substrate was measured, the maximum thickness unevenness was 50 μl, which was sufficiently small. The value of birefringence was 20 ns in a single pass, and there was little variation. The amount of surface runout was sufficiently small, with a pp ratio of 50 l. The transfer rate of the preformat pattern formed on the stub bar was 98% or more in terms of depth.

This substrate was cut into 861 mφ in the same way as in Example 1.
After forming the optical recording layer, a protective substrate was adhered to obtain an optical disc. When recording and reproducing the obtained optical disc, the rotation speed of the disc was 1800 rpm, 11, the writing frequency was 3 MHz, and the writing power was 6 IjlW, +iiC.
Output power 0.5mW ""Q, C/N ratio S[
] There was a dBte.

Comparative Example 1 Using the same method as in Example 1, 1 epoxy resin (Diabon 1-2000S, manufactured by Nozawa Kamikal) and diethylene triamine (Kanto Kagaku) were uniformly mixed at a weight ratio of 14:l on an iron roller with a roller diameter of 350 mmφ to produce 50 g. A nickel stump bar having a thickness of 90 gm, which is the same as in Example 1, was applied in the same manner as in Example 1. The thermal conductivity of the adhesive after curing was 15 W/aK.

This roller was attached to the same extrusion molding machine as in Example 1, and the same resin was extruded under the same conditions as in Example 1.

When the extrusion molded substrate was measured, the thickness unevenness was 90 gm, which was larger than that of Example 1. Birefringence is 60 to 190 n■ in a single pass, and the difference is large depending on the location. The amount of surface runout is 100 g pp
(2) was larger than in Example 1. These values are
Since it was significantly inferior to Examples 1 to 3, it was impossible to measure the recording/reproducing characteristics.

[Effects of the Invention] As explained above, according to the molding mold of the present invention, the thermal conductivity of the mold is good, so the pattern transferability is good, and the distribution of the amount of heating is uniform, which makes the molding process easier. This has the effect of providing a substrate for an optical recording medium which has small thickness unevenness and birefringence unevenness and has good surface precision.

[Brief explanation of the drawing]

FIG. 1 is a cutaway sectional view showing one embodiment of a mold for molding an optical recording medium substrate of the present invention, FIG. 2 is a schematic diagram thereof, and FIG.
The figure is a schematic diagram showing a method for manufacturing an optical recording medium substrate using the molding die of the present invention, FIG. 4 is a schematic diagram showing a conventional method for manufacturing an optical recording medium substrate, and FIG. 5 is a conventional method. 1 is a sectional view showing an optical recording medium of FIG. 1...Roller 2...Stambar 3...
・Adhesive layer 4... Molding roller 5...
Extrusion molding machine 6... Pressure roller 7... Take-off roller 8... Resin sheet 11... Thermoplastic resin 12... Molded disk

Claims (3)

[Claims] (1) The resin sheet extruded from the extrusion molding machine,
In a molding die for forming a preformatted optical recording medium substrate by passing the stamper between a molding roller and a pressure roller of the mold, the molding roller has a thin stamper on the surface of the roller, A mold for molding a substrate for an optical recording medium, characterized in that the mold is laminated with a uniform mixture of an adhesive and powder particles of a metal or a metal compound. (2) The mold for molding an optical recording medium substrate according to claim 1, wherein the molding roller has a thermal conductivity of 20 W/mK or more. (3) The material of the thin stamper provided on the molding roller is metal or a metal compound, and its thickness is 10 to 2
2. The mold for molding a substrate for an optical recording medium according to claim 1, wherein the mold has a diameter of 00 μm.