JPH08147769A - Optical disk stamper, method of manufacturing the same, and method of manufacturing optical disk - Google Patents

Abstract

(57) [Abstract] [Purpose] An optical disk substrate obtained by resin molding can be easily separated from a stamper which is a master disk for optical disks during molding. [Structure] In the manufacture of optical discs, an organic solvent, paraffinic or olefinic hydrocarbon, or dialkyl siloxane or trialkoxy monoalkyl silane is applied as a release agent and fixed on the stamper surface after forming a signal. Mounted on a mold to form an optical disk substrate. [Effect] A strong release layer having a thickness of about one molecule can be formed on the stamper, and the optical disc can be easily peeled from the stamper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc master for producing optical discs such as video discs, digital audio discs, still images, and document files. The present invention relates to a method for manufacturing an optical disc.

[0002]

2. Description of the Related Art Generally, an optical disc is promising as an information medium due to its extremely high information density, large S / N ratio and little noise, and is commercialized as a video disc for recording and reproducing digital signals. In recent years, research and development have also been performed on optical discs.

A conventional example will be described below with reference to the drawings. 8 and 9 are cross-sectional views of a mold at the time of conventional resin molding, and FIG. 10 is a flowchart showing a manufacturing process of a conventional optical disk stamper.

A conventional optical disk manufacturing method will be described with reference to these drawings. The stamper 2 whose back surface and inner and outer circumferences are processed to fit the molding die is mounted on the surface of the movable die 1 whose temperature is adjusted to 80 ° C. or higher, and then the cavity 4a is formed on the surface of this stamper. The fixed mold 4 as shown in FIG.
The resin 6 melted at the above high temperature is injected, pressure is applied, and then cooling is performed.

Next, the movable die 1 is moved to the left, and at the same time as the movement, the cut punch in the shaft portion 1a of the movable die 4 is extruded toward the fixed die 4, whereby the resin molded product 7 is removed. The center part is cut, and then the floating punch 9 outside the cut punch 8 is pushed out to separate the resin molded product 7 from the stamper 2.

[0006] Here, the resin melted at 300 ° C or higher is injected onto a stamper whose temperature is controlled at 80 ° C or higher, and
Since it is compressed at a high pressure, it is very difficult to separate the resin molded product from the molding die at the timing and withdrawal.

[0007]

A problem in the above-mentioned conventional method has occurred when the resin molded product is separated from the stamper during molding.

The cause of this is that innumerable protrusions for forming signals are formed on the surface of the stamper, and these protrusions penetrate into the surface of the resin molded product (optical disk) to be in a buried fitting state. As a result, the stamper and the resin molded product are in a state of being strongly bonded to each other, and if the resin molded product is forcibly separated from the stamper surface after it has been cooled and solidified, this separation is uniform. However, there is a problem that the surface of the resin molded product on the stamper side, that is, the signal side surface is damaged or the signal is deformed.

As a result, the characteristics are adversely affected. Therefore, it is an object of the present invention to prevent the surface from being scratched or the signal from being deformed when the optical disk is detached from the stamper.

[0010]

In order to achieve this object, according to the present invention, a mold release agent is applied on the surface of a stamper before the injection molding process, and then a mold is mounted on the stamper. The resin molded article is manufactured by injecting.

[0011]

By applying the release agent to the stamper surface and mounting it on the mold as described above, even if the signal forming convex portion on the stamper surface is embedded in the resin molded product during molding, This release agent allows easy release, and more uniform release in the circumferential direction makes it easier to remove the finished optical disc.

[0012]

1 and 2 are cross-sectional views of a molding die in a method for manufacturing an optical disc according to this embodiment, in which 1 is a movable die, 2 is a stamper, 3 is a release agent, 4 is a fixed die, 4a. Is a cavity, 5 is an injection port, 6 is a resin, 7 is a resin molded product, 8 is a cut punch, and 9 is a floating punch.

FIG. 3 is a plan view showing a stamper used in this embodiment, and shows a state where a release agent is applied to a part of the surface of the stamper. Reference numeral 2a is a signal or a convex portion of a groove, 2b is a through hole, and 3 is an area coated with a release agent.

FIG. 4 (a) is a sectional view of the stamper in this embodiment, in which 2 is a stamper and 3 is a release agent.
The stamper 2 may have a sectional configuration shown in FIG. 4B, for example. In FIG. 4B, 2 is a stamper and 3 is a release agent.

FIG. 5 is a plan view of a resin molded product (optical disk) molded by the molding die shown in FIG. FIG. 6 is a cross-sectional view thereof, 7 is a resin molded product, and 7a is a central hole.

FIG. 7 is a manufacturing flowchart of the optical disk stamper used in this embodiment.

A method of molding an optical disc in this embodiment will be described. In FIGS. 1 and 2, reference numeral 1 denotes a movable mold, and a stamper 2 shown in FIGS. 3 and 4 is provided on the surface of the movable mold 1.
Is installed. Reference numeral 4 denotes a fixed mold, which is moved from a state where the movable mold 1 is separated as shown in FIG. 2 as shown in FIG. 1. In this state, a cavity 4a is formed on the surface of the stamper 2.

An injection port 5 is formed integrally with the fixed mold 4 at the central axis portion thereof, and the cavity 4 is formed as shown in FIG.
After a is formed, a resin 6 such as polycarbonate is injected from this injection port 5 under pressure.

When the resin 6 is cooled, a resin shaped product 7 is formed in the cavity 4a as shown in FIG. 2. In this state, the movable mold 1 is first shown in FIG. Move it to the left.

Almost at the same time as the movement of the movable mold 1 to the left, the cut punch 8 in the shaft portion 1a of the movable mold 1 is pushed out toward the fixed mold 4, whereby the center portion of the resin molded product 7 is pushed. Through holes 7a are formed as shown in FIGS.

Next, the floating punch 9 on the outside of the cut punch 8 is pushed out, whereby the resin molded product 7 (optical disk) is separated from the stamper 2.

In FIGS. 1 and 2, the stamper 2 shown in FIGS. 3 and 4 is mounted on the surface of the movable mold 1.
The stamper 2 is manufactured based on the optical disk manufacturing flowchart shown in FIG. 7, and is obtained by introducing a mold release agent applying step and a mold release agent curing step before the injection molding step. is there.

Further, in the stamper 2 shown in FIG. 4A, the upper side is a signal forming surface, and although not shown in the range of 2a shown in FIG. 3, innumerable signals or The convex portion of the groove is formed. Also, stamper 2
The release agent 3 is attached to the inside of the portion 2a as shown in FIGS. 3 and 4 (a). Furthermore, by applying the coating only to this portion, there is no direct influence on the signal portion, and the countermeasure against dropout is perfect.

The release agent 3 is composed of at least one of paraffin hydrocarbons, olefin hydrocarbons, organic solvents, compounds having the structural formula shown in Chemical formula 3, dialkyl siloxanes and trialkoxy monoalkyl silanes.

[0025]

Embedded image

This is transferred to the stamper 2 by using, for example, a cylindrical stamp (not shown), and then 80 ° C. to 120 ° C.
It is heated and cured for 20 minutes or more. As a result, the release agent adheres strongly to the stamper surface.

The feature of the release agent used in this example is that an extremely thin release agent layer having a thickness of about a single molecule can be formed. Therefore, even if the optical disc is press-molded using the stamper having the release layer coated on the signal pits, it is possible to obtain an optical disc which is not affected by the release layer at all.

Moreover, since the release agent adheres firmly to the above heat treatment, a large amount of optical disks can be pressed by forming the release agent once.

When the stamper shown in FIG. 4B is used, the stamper is performed as follows. In FIGS. 1 and 2, the stamper 2 shown in FIG. 4B is mounted on the surface of the movable mold 1. The stamper 2 is manufactured according to the optical disk manufacturing flowchart shown in FIG. 7, and is obtained by introducing a mold release agent applying step and a mold release agent curing step before the injection molding step.

In this case, the stamper 2 has a signal forming surface on the upper side in FIG. 4 (b), and although not shown in the range of 2a shown in FIG. 3, innumerable signals or convex portions of grooves are formed. Are formed. Further, the release agent 3 is attached to the entire surface of the stamper 2 for signal formation as shown in FIG. 4B. A wet rotation method is used as a means for coating the entire surface at a rotation speed of 1500 rpm for a time of 5 minutes to form a thin monomolecular film uniformly, so that the molded product can be easily released.

In particular, when the stamper has no inner hole and is rotated after coating, there is no risk of the release agent sneaking into the inner hole and splashing, and the dropout countermeasures are perfect.

The release agent 3 is composed of at least one of paraffinic hydrocarbons, olefinic hydrocarbons, organic solvents, compounds having the structural formula shown in (Chemical Formula 3), dialkylsiloxanes and trialkoxymonoalkylsilanes. .

This is transferred to the stamper 2 using, for example, a cylindrical stamp (not shown), and then 80 ° C. to 120 ° C.
It is heated and cured for 20 minutes or more.

3 and 4 is a through hole for fixing the stamper 2 to the shaft portion 1a of the movable mold 1.

At this time, since the release agent 3 is attached to the surface of the stamper 2 on the side of the resin molded product 7 as shown in FIGS. 3 and 4, the resin molded product 7 is removed from the surface of the stamper 2 internally. This is performed substantially uniformly and smoothly from the entire circumference, and as a result, the signal side surface of the resin molded product 7 is not scratched.

The mold release agent 3 is hardened by heat as described above, so that the resin molded product 7 becomes about 100,000.
It is designed so that the effect can be fully exerted up to about one sheet.

[0037]

As described above, according to the present invention, the mold release agent is applied to the surface of the stamper, then the mold release agent is mounted in the cavity, and the resin is injected from the injection port.

As described above, when the mold release agent is applied to the surface of the stamper, the mold is mounted in the cavity, and the resin is injected from the injection port, the convex portion for signal formation on the surface of the stamper is embedded and fitted in the resin molded product. However, the release agent makes it possible to easily release it, and since the release state becomes more uniform in the circumferential direction, the finished optical disc will not be scratched, and signal deformation etc. will be prevented. be able to.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a molding state in an embodiment of a method for manufacturing an optical disc of the present invention.

FIG. 2 is a cross-sectional view showing a taken-out state of a molded product (optical disk) in the example.

FIG. 3 is a plan view of a stamper used in the same embodiment.

FIG. 4 is a sectional view of the stamper.

FIG. 5 is a plan view of an optical disc molded in the same example.

FIG. 6 is a sectional view of the optical disc.

FIG. 7 is a flowchart of the manufacturing method of the same embodiment.

FIG. 8 is a cross-sectional view of a conventional optical disc manufacturing die.

FIG. 9 is a sectional view of the conventional mold.

FIG. 10 is a flowchart showing a conventional optical disc manufacturing method.

[Explanation of symbols]

 1 Movable mold 2 Stamper 3 Release agent 4 Fixed mold 4a Cavity 5 Injection port 6 Resin 7 Resin molded product

Claims (6)

[Claims] 1. A stamper for an optical disk, wherein a release agent is applied to at least a part of an inner circumference of a signal surface. 2. The mold releasing agent according to claim 1, which comprises at least one of an organic solvent, a paraffinic hydrocarbon, an olefinic hydrocarbon, a compound having a structural formula shown in Chemical formula 1, and a dialkylsilonxane. Stamper for optical disc. Embedded image 3. A method of manufacturing a stamper for an optical disk, wherein after forming a signal on the stamper, a release agent is applied to at least a part of an inner peripheral portion of a signal surface and heat treatment is performed. Manufacturing method for stamper. 4. The method of manufacturing an optical disk stamper according to claim 3, wherein the release agent is applied to the signal surface of the stamper in a state where the stamper has no inner hole. 5. A release agent comprising at least one of an organic solvent, a paraffinic hydrocarbon, an olefinic hydrocarbon, a compound having a structural formula shown in (formula 2) and a dialkylsilonxane is used as the release agent. 4. The method for manufacturing a stamper for an optical disc according to claim 3, wherein. Embedded image 6. A method of manufacturing an optical disc, comprising using a stamper having a release agent fixed to at least a part of an inner circumference of a signal surface, and injecting a resin from the inner circumference into a mold equipped with the stamper to mold the resin.