JPH06215517A - Flat information recording medium and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] When manufacturing a magnetic clamp type optical disc, a clamp part called a hub is formed on the disc as a guide groove,
The purpose is to improve the accuracy when fixing the pre-pit row and core together and to simplify the manufacturing method. A hub is formed by integrally molding a magnetic body 10 in the center of the disk at the same time as molding the disk substrate 2, and the positioning accuracy of the hub and the guide groove of the disk is fixed.
The fixing strength can be improved, and it is unnecessary to retrofit the hub, and the work required for centering and fixing can be omitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat information recording carrier capable of high-capacity and high-density recording, and more particularly to fixing a disk of an optical disk which is a disk-shaped recording medium.

[0002]

2. Description of the Related Art A clamp method for rotatably fixing an optical disk to a disk motor for rotating an optical disk is a mechanical clamp for mechanically sandwiching a central hole formed in the central part of the disk from both sides and fixing it to a rotary shaft of a recording / reproducing apparatus. There is a method and a magnet clamp method in which a magnet is provided in the vicinity of the rotation axis of the recording / reproducing apparatus and a disk having a magnetic material in the center is fixed by the magnet. The present invention relates to a magnetic clamp type disc.

A conventional technique will be described below with reference to the drawings. 3A and 3B are schematic views showing the structure of a conventional optical disc. In the figure, 2a and 2b are disk substrates, 5a and 5b are supporting parts for fixing the disk to the rotating mechanism, and magnetic bodies 10a and 10b are fixedly provided in the central portion, and are generally called hubs. ing.

Reference numerals 7a and 7b are hub fixing agents.
Further, FIGS. 4A to 4E show a manufacturing process of the above-mentioned conventional optical disc.

FIG. 4 (a) shows a disk-shaped stamper 1 having concentric or spiral minute guide grooves 9'formed on its surface.
Is.

As shown in FIG. 2B, the stamper 1 is used as a master and the guide groove 9'is formed by an injection molding method using a hot-melt resin or a photopolymer molding method using an ultraviolet curable resin (hereinafter referred to as 2P molding method). ) Or the like to produce an optical disk substrate 2 transferred to a transparent thermoplastic resin (acrylic, polycarbonate, etc.). At this time, the center hole 8 is formed in the optical disk substrate 2 together with the guide groove 9.

The recording surface of the disk substrate 2 has a micron-order spiral or concentric circular guide groove, or a pre-pit that carries information by interrupting the guide groove or changing the shape of the guide groove.

Then, as shown in FIG. 4C, the recording film 3 made of a metal thin film is formed on the upper surface of the guide groove 9 formed on the substrate 2 by sputtering, vacuum deposition or the like.

Next, as shown in FIG. 4 (d), for the purpose of protecting the recording film 3 from oxidation, scratches, etc., a protective coating layer 4 made of a photocurable resin is recorded by spin coating or the like. It is formed on the upper surface of the film 3.

Next, as shown in FIG. 4 (e), the center hole 6
And the hub 5 made of a magnetic material is attached to the ultraviolet curable adhesive 7
To bond and fix the substrate 1. At the time of joining, the center of the center hole 6 of the hub 5 and the center of the guide groove 9 of the substrate 1 are made substantially the same.

In addition, as a means for forming a hub on an optical disk, as described in Japanese Patent Laid-Open No. 62-192946 and Japanese Patent Laid-Open No. 4-77392, a magnetic material alone, a resin and a metal plate are integrated. A method of joining a hub, which is formed or is formed of a plastic molded product in which magnetic powder is mixed, to a substrate by ultrasonic welding, heat welding, adhesion or the like is generally used.

The above-mentioned manufacturing method is for a single-sided disk, but for a double-sided disk, it can be realized by laminating two disk substrates with the recording surface inside.

[0013]

In the conventional structure and manufacturing method as described above, a hub and a means such as an adhesive for fixing the hub to the disk are required when manufacturing the disk, and the guide groove or the information is stored. It took a lot of time and effort to align the center of the pre-pit row and to fix it.

[0014]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and provides a magnetic material in the center of a disk substrate at the same time when the disk substrate is molded.

[0015]

With the above-described structure and manufacturing method of the disk, means for fixing the hub to the disk is not required, and the labor and time required for alignment with the guide groove or the pre-pit row carrying information can be saved, and the hub and the disk can be omitted. The accuracy of the fixed position with respect to the guide groove and the fixing strength are improved, and the disk manufacturing process can be simplified.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an optical disk according to one embodiment of the present invention, in which a plastic substrate having guide grooves or pre-pits for carrying information is injection-molded and at the same time a magnetic material is integrally molded in the central portion on the light input surface side. It is a figure.

In FIG. 1A, a resin protrusion is provided on the central light-incident surface side of the disk substrate 1, and a magnetic metal 10 is integrally formed on the protrusion 5 at the same time when the substrate is molded. The outer diameter of the resin protrusion may be used for positioning with the disc motor of the recording / reproducing device. Alternatively, a center hole may be opened in the center of the magnetic metal, and the center hole may be used for recording / reproducing. Positioning with the disc motor of the device may be performed. Further, the portion where the magnetic metal is provided may be substantially flush with the disk surface.

In FIG. 1 (b), a recess 17 for positioning with the disc motor of the recording / reproducing apparatus is provided on the central light-incident surface side of the disk substrate 1, and the magnetic metal 10 is the light-incident surface of the disk. It is integrally molded at the same time as the molding of the substrate on the opposite side. In this case, a protrusion portion of resin may be provided on a portion where the magnetic metal is provided in the central portion of the disc, or may be substantially flush with the disc surface. In addition, the positioning of the disk motor of the recording / reproducing device is performed by the recess 1
Instead of 7, it may be a through hole. Further, a through hole may be formed in the center of the resin substrate, a center hole may be provided in the center of the magnetic metal, and the center hole of the magnetic metal may be used for positioning with the disc motor of the recording / reproducing apparatus. Further, the magnetic metal may have a hole necessary for molding other than the central portion.

FIG. 1 (c) shows a disk substrate 1 having a central portion 18 in which magnetic powder is mixed. This portion may reach from the light-incident surface side of the disc to the non-light-incident surface side, or may extend from either one side to the inside of the disc substrate. The resin in which the magnetic powder is mixed may be the same as or different from the substrate material. Positioning of the disc and the disc motor of the recording / reproducing apparatus may be performed by providing a hole at the center of the disc in the portion in which the magnetic powder is mixed, or by providing a protruding portion on the disc.

Next, an embodiment of a method of manufacturing the above-mentioned single-piece planar information recording medium will be described with reference to the drawings.

FIG. 2 is a cross-sectional view of an injection molding die of a plastic substrate having a guide groove or a prepit for carrying information. By performing injection molding, at the same time when the disk substrate is molded, a magnetic material is formed in the central portion of the substrate. The body metal is integrally molded.

The disk substrate molded by the mold shown in FIG. 2 is of a magnet clamp type in which the central position of the magnetic metal arranged in the center position with the disk motor of the recording / reproducing apparatus.

In FIG. 2, 12 is a core insert (male type), 11 is a cavity insert (female type), 2 is a cavity (material filling space), and the cavity 2 is sandwiched between the core insert 12 and the cavity insert 11. The disk substrate is formed by injecting a molten resin into the space and solidifying the resin.

Reference numeral 1 is a stamper arranged in the cavity for transferring the guide groove to the disk substrate, 15 is a stamper holder for fixing the inner circumference of the stamper 1, and 13 is an outer ring for fixing the outer circumference of the stamper 1. is there. Reference numeral 14 is an ejector in which the magnetic metal 10 having a center hole is fitted so that the center hole and the guide groove of the stamper 1 are at the same center, and the molded disk substrate is taken out. Reference numeral 16 is an inlet for injecting a resin material.

In the disk substrate molding die having the above-described structure, the magnetic metal 10 is placed in the cavity 2 in advance before molding, and injection molding is performed. The magnetic metal can be integrally formed on the central portion of the substrate.

According to the above-mentioned method, if the concentricity of the stamper 1 with the ejector 14 for mounting the metal magnetic body 10 is matched, it is possible to easily form a hub having a highly accurate mounting position.

Although only the case where the disk substrate is molded by the injection molding method has been described in the embodiment, the 2P molding method using an ultraviolet curable acrylic resin or the like can be carried out with the same configuration. is there.

Further, the automatic insertion of the magnetic metal from the rear of the injector in order to continuously position the magnetic metal in the cavity at the time of molding means that the magnetic metal which is easily separated from the inside of the injector is used. It is possible to insert a plurality of them and control the thickness in the cavity space from the rear of the injector by a screw structure or the like. Further, the method of continuously molding is not limited to the above.

Further, fine protrusions or dents are formed on the resin-bonded surface of the magnetic metal in order to strengthen the resin-bonding.
It is effective to apply grooves or the like to control the surface roughness, or to apply in advance an adhesive that softens at the temperature at the time of extrusion molding in the injection molding method.

[0031]

As described above, by forming the clamp resin annular protrusion or the magnetic body as the hub in the central portion of the disc substrate at the same time when the disc substrate of the magnet clamp system is formed, the hub and the guide groove of the disc are formed. The fixing position accuracy and the fixing strength can be improved, and the disk manufacturing process can be simplified, so that the effect of the present invention is great.

[Brief description of drawings]

FIG. 1 is a sectional view of a disk showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an injection molding die for molding an optical disk substrate showing an embodiment of the present invention.

FIG. 3 is a cross-sectional view of a disk that is a conventional example.

FIG. 4 is a diagram showing a manufacturing process of a disk which is a conventional example.

[Explanation of symbols]

 1 Stamper 2 Disk Substrate 3 Recording Film 4 Protective Coating 5 Hub 6 Center Hole 7 UV-Curing Adhesive 8 Substrate Center Hole 9 Guide Groove 10 Magnetic Metal 11 Cavity Insert 12 Core Insert 13 Outer Ring 14 Ejector 15 Stamper Holder 16 Resin Inlet 17 Indentation 18 Magnetic powder mixing part 19 UV lamp

Claims (8)

[Claims] 1. A flat plate information recording carrier of a magnet clamp type in which a reflective film or a recording medium is formed on a plastic substrate for reproducing, recording or erasing information by using light, and reproducing, recording or recording the information. A flat information recording medium characterized in that a magnetic material is integrally formed in the central part of the substrate at the same time when a plastic substrate having a guide groove or a prepit for carrying information when erasing is formed. 2. A magnet clamp type flat information record carrier, which is formed at the same time as molding of a plastic substrate having guide grooves or prepits for carrying information when reproducing, recording or erasing information, and at the same time, at the center of the substrate. A flat plate-shaped information recording carrier, characterized in that it is formed of the same resin as the substrate and a ring-shaped protrusion that is clamped to the substrate, and a magnetic material is integrally molded in the center of the ring-shaped protrusion. 3. The flat information record carrier according to claim 1, wherein the magnetic substance in the central portion is a metal. 4. The flat information recording carrier according to claim 1, wherein the magnetic material in the central portion is made of plastic mixed with magnetic material powder. 5. The flat information record carrier according to claim 1, wherein the magnetic material at the center has a hole. 6. A method for manufacturing a flat information recording carrier, wherein a magnetic material as a clamp member for moving the information medium relative to the signal recording / reproducing head is simultaneously formed at the time of molding the substrate. 7. A method of injection molding, in which a molten resin is injected into a space in which a magnetic material is aligned with a stamper center of a disk substrate and inserted into a mold for injection molding when molding a substrate. 7. The method for manufacturing a flat information record carrier according to claim 6. 8. A photopolymer molding method of injecting an ultraviolet curable resin into a space in which a magnetic material is inserted into a mold for molding when a substrate is molded in alignment with the stamper center of a disk substrate. 7. The method for manufacturing a flat information carrier according to claim 6.