JP2002144377A - Tapered molding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding apparatus and a manufacturing method for molding a disk substrate which does not cause a face deflection and a worse tilt in an axial direction by easily exactly removing a disk substrate from a mold for molding a concave and convex pattern i.e., so-called a pit or a pre-groove composing a recording track and to provide a substrate manufactured thereby. SOLUTION: A molding apparatus for molding a disk substrate which molds a synthetic resin to form a disk substrate is provided with a fixed mold (1) and a movable mold (2) both composing a cavity (4) for molding the disk substrate wherein a mold-releasing resistance portion (a taper) is mounted at a position corresponding to an edge surface of an outer circumference side of the substrate main body formed by the fixed mold (1) or the movable mold (2).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk substrate molding metal for molding a disk substrate formed by molding a synthetic resin material constituting a disk serving as an information signal recording medium, such as an optical disk or a magneto-optical disk. The present invention relates to a mold device, a manufacturing method, and an optical disk substrate.

[0002]

2. Description of the Related Art Hitherto, an optical disk using a disk substrate formed of a synthetic resin material such as a polycarbonate resin having a light transmitting property has been proposed. As this type of optical disk, there are known a read-only optical disk which only reproduces an information signal recorded in advance, and a rewritable magneto-optical disk which can rewrite an information signal once recorded. I have. The read-only optical disk is formed by, for example, vapor-depositing aluminum or the like on one main surface side of a disk substrate on which a so-called pit is formed, which is an uneven pattern corresponding to an information signal such as a predetermined music signal. It is configured by providing a reflection film. Further, a magneto-optical disk capable of rewriting information signals has a signal recording layer having a magnetic film on one main surface of a disk substrate on which a pre-groove forming a recording track on which a desired information signal is recorded is formed. It is formed and formed. This type of optical disc can record information signals such as digitized music signals at extremely high density. 64m diameter
There has been proposed a device that can record and reproduce a music signal for at least 74 minutes or only reproduce the music signal.

This optical disk has a disk substrate formed by molding a synthetic resin material such as a polycarbonate resin having optical transparency, and one main surface on which a pre-groove forming a recording track of the disk substrate is formed. A signal recording layer is formed by applying a perpendicular magnetization film or the like on the side. The recording of the information signal on the optical disc is performed by rotating the optical disc at a predetermined rotation speed while a light beam emitted from an optical pickup is provided on a recording track provided in a signal recording section on which a signal recording layer is formed. And applying a magnetic field modulated in accordance with an information signal to be recorded from an external magnetic field generator.

[0004] Since the above-mentioned optical disk has a small diameter and fine recording tracks formed at a high density, a disk of a disk rotation drive mechanism provided in a disk recording and / or reproducing apparatus for rotating this optical disk. In addition to being accurately positioned and mounted on the table, it must be securely integrated with and mounted on the disk table, and driven to rotate in synchronization with the rotation of the disk table.

Incidentally, a disk substrate formed by molding a synthetic resin material such as a polycarbonate resin constituting the above-mentioned optical disk is molded by a mold device for injection molding. The mold device for molding the disk substrate includes a fixed mold and a movable mold that constitute a molding cavity corresponding to the disk substrate.For example, a predetermined mold is provided on the disk mold surface side of the fixed mold. A stamper for forming a so-called pit, which is a concavo-convex pattern corresponding to an information signal such as a music signal, or a pre-groove forming a recording track on which a desired information signal is recorded, is provided. A punch is provided to form a centering member engaging hole provided in the portion.

The molding of a disk substrate using the above-described mold apparatus is performed by injecting and filling a molten synthetic resin material into a molding cavity through an injection port of a sprue bush arranged in a fixed mold. After forming the disk substrate in the forming cavity, a centering member engaging hole was formed in the center by moving the punch, and a pit or pregroove was formed on one main surface side. The disk substrate is formed.

The optical recording medium, the substrate for the optical recording medium, and the mold apparatus for molding the substrate are described in, for example, Japanese Patent Application Laid-Open No. 5-20842.
Japanese Patent Application Laid-Open No. 9-205, in which a release resistor portion having an uneven portion is provided on a fixed mold side at a portion corresponding to an outer peripheral side wall of a disk substrate or a portion corresponding to an inner wall of a protrusion protruding from an inner central portion. Is described. In the method disclosed in Japanese Patent Application Laid-Open No. Hei 5-208429, a disk substrate formed from a pit which is a concavo-convex pattern or a stamper for forming a pre-groove forming a recording track can be easily and reliably released. As the cycle is shortened, the release resistance due to the reverse taper increases, and if the mold cannot be easily released from the mold, especially the surface runout due to the mechanical characteristics and the axial tilt deteriorate. Is known,
It cannot be used as a disk substrate of an optical disk.

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention provides an easy and reliable mold release of a disk substrate from a mold for molding a so-called pit or a pre-groove forming a recording track, which is a concavo-convex pattern. The present invention has been proposed for the purpose of providing a disk substrate molding die apparatus and a manufacturing method that do not cause surface runout of a disk substrate to be performed and deterioration of an axial tilt, and a substrate manufactured by the same. .

[0009]

The object of the present invention is to provide a disk substrate molding cavity (4) in a mold apparatus for molding a disk substrate, which is formed by molding a synthetic resin material. A fixed-side mold (1) and a movable-side mold (2) are provided, and correspond to the outer peripheral end surface of the substrate body formed into the fixed-side mold (1) or the movable-side mold (2). A disk device forming die device provided with a tapered release resistance portion at a position ", (2)" the tapered release resistance portion is tapered to 1 to 10 degrees. (3) “Method of forming and manufacturing optical disk substrate formed by (2)”, (4) “(2)) The optical disk substrate formed by the item is achieved.

According to the present invention, there is provided a mold apparatus for molding a disk substrate, which is formed by molding a synthetic resin material and has a projection protruding from an inner peripheral side of the substrate body. A fixed mold that forms a disk substrate molding cavity, and a movable mold that is disposed opposite to the fixed mold and forms a disk substrate molding cavity together with the fixed mold. A release resistor is provided on the outer peripheral surface at a position corresponding to the outer peripheral edge of the substrate body on which the fixed mold or the movable mold is formed.

[0011]

The present invention will be described below in detail with reference to examples. A specific embodiment of the disk substrate molding die apparatus according to the present invention will be described with reference to the drawings. As shown in FIG. 1, the disk substrate forming die apparatus is provided with a fixed side die (1) and a fixed side die (1) via a hydraulic mechanism or the like so as to be able to advance and retreat in a direction of approaching and separating from the fixed side die. A mold (3) comprising a supported movable mold (2) is provided. The fixed mold (1) and the movable mold (2) constituting the mold (3).
A molding cavity (4) corresponding to the disk substrate (11) to be molded is defined between them. On the side of the fixed mold (1), a synthetic resin material such as a molten polycarbonate resin supplied from an injection molding machine is provided at the center of the molding cavity (4). ) Are provided. A resin injection nozzle (5a) is formed in the center of the sprue bush (5), and a molten synthetic resin material supplied from an injection molding machine is supplied to the molding cavity (4) through the resin injection nozzle. It is injected inside.

On the outer peripheral side of the sprue bush (5),
A holder support (1) in which an inner peripheral stamper retainer (12) for supporting an inner peripheral side of a stamper (7) described later is fitted and disposed.
5) is fitted and arranged. On the molding surface defining the molding cavity (4) of the fixed mold (1), so-called pits, which are minute concave / convex patterns corresponding to information signals recorded on the optical disk, or signal recording portions of the optical disk. Is mounted with a stamper (7) for forming a pre-groove forming a recording track formed in the recording track. The stamper (7) has a peripheral edge of the center hole supported by an inner peripheral side stamper retainer (12) fitted and disposed on the holder support, and the outer peripheral side is sucked and attached by air suction from a suction port (14). Be done. On the other hand, the center of the movable mold (2) on the molding surface side that defines the molding cavity (4) cooperates with the protrusion (13) molding portion provided on the fixed mold (1). The protrusion (1) protruding from the other main surface of the disk substrate
A projection forming recess (17) for forming 1a) is formed. In the center of the projection forming recess (17), a punching punch () of a punching cut punch mechanism for punching and forming a centering member engaging hole formed as a through hole (11b) at the center of the projection (13). 9) is provided. The punch (9) is made of a sleeve (18)
The movable mold (2) is disposed so as to advance and retreat inside. The sleeve is supported so as to be able to advance and retreat with respect to the movable mold (2), and pushes out the formed disk substrate from the movable mold (2).

Then, on the outer peripheral side of the movable mold (2),
A cavity (8) of a disk outer peripheral surface forming member for forming an outer peripheral side surface of a disk substrate to be molded is provided while defining an outer peripheral side of the molding cavity (4). The cavity (8) has a smooth end surface on the tip end side, and is arranged so as to touch a stamper attached to the fixed mold (1). When the movable mold (2) is moved to the fixed mold (1), the cavity (8) is brought into contact with the stamper when the movable mold (2) is moved to the fixed mold (1). A molded disk substrate is made to seal the cavity (4).

The molding surface of the movable mold (2) is on the light beam incident surface side of the disk substrate so that the other main surface of the disk substrate, which is a smooth surface with high precision, can be molded. In addition, the mirror surface is a highly accurate smooth surface. After the disk substrate is formed, when the mold is opened to move the movable mold (2) away from the fixed mold (1), the disk substrate is held on the movable mold (2) side. Then, the ejector pins (10) in the movable mold are projected to release the disk substrate from the movable mold (2).

In order to form a disk substrate by using the mold apparatus configured as described above, the movable mold (2) is brought into the mold-clamped state close to the fixed mold (1). In this mold clamping state, a synthetic resin material such as a molten polycarbonate resin supplied from an injection molding machine is injected into the molding cavity (4) through the resin injection port of the sprue bush (5). At this time, the punch 9 is moved to form a centering member engaging hole at the center of the projection. Next, the movable mold (2) is moved to the fixed mold (1) side, and the mold is compressed to compress the synthetic resin material filled in the molding cavity (4), and the mold is cooled. The molding cavity (4)
Is formed. In the mold device configured as described above, the inner peripheral surface for molding the outer peripheral surface of the disk substrate to be molded is moved along with the cavity defining the outer peripheral side of the cavity (4). The tapered surface is reduced in diameter toward 2). On the other hand, the outer peripheral surface of the movable mold (2) to be fitted at the time of molding the disk substrate is formed into a tapered surface so as to increase the diameter. The outer peripheral side of the disk molding cavity (4) has a tapered shape whose diameter increases from the movable mold (2) toward the fixed mold (1).

[0016]

[Table 1]

[0017]

As is apparent from the above detailed and specific description, the disk substrate molding die apparatus of the present invention is provided on the outer peripheral side of the substrate body on which the fixed die or the movable die is molded. Since the release resistance portion (taper) is provided at the corresponding position, it is possible to reliably release the disk substrate from the mold after molding the disk substrate, to prevent a release failure and to prevent molding distortion. In addition to making it possible to form a disk substrate without causing the occurrence of a disk substrate, the molded disk substrate can be easily taken out of the mold, and mechanical characteristics of surface runout and axial tilt can be reduced. This is an extremely excellent effect that the substrate can be formed without deterioration.

[Brief description of the drawings]

FIG. 1 is a schematic view of a disk substrate molding die apparatus of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 fixed mold 2 movable mold 3 mold 4 molding cavity 5 sprue bush 5a resin injection nozzle 7 stamper 8 cavity ring 9 punching punch 10 ejector pin disk substrate 11a protrusion 11b through hole 12 inner stamper retainer 13 Projection 14 Suction port 15 Holder support 17 Projection forming recess 18 Sleeve

Claims (4)

[Claims] 1. A mold device for molding a synthetic resin material and molding a disk substrate, comprising: a stationary mold (1) constituting a disk substrate molding cavity (4);
A movable-side mold (2), and a tapered mold-release resistor at a position corresponding to the outer peripheral end surface of the substrate body formed on the fixed-side mold (1) or the movable-side mold (2). A disk substrate molding die device provided. 2. The taper-type release resistance part is 1 ° to 1 °.
2. A taper processing at 10 [deg.].
4. The die apparatus for molding a disk substrate according to item 1. 3. A method for forming and manufacturing an optical disk substrate, wherein the method is performed by molding according to claim 2. 4. An optical disk substrate formed according to claim 2.