JP2000202881A - Mold apparatus and method for molding disc-shaped recording medium substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the deformation of a substrate to be molded or the variation of characteristics at a time of the injection molding of the substrate of a disc-shaped recording medium from a resin material. SOLUTION: A fixed mold part 2, the movable mold part 3 opposed to the fixed mold part 2 in a separable manner, the annular outer peripheral ring part 4 provided to the movable mold part 3 so as to be slidable in an approaching and separating direction with respect to the fixed mold part 2 and an outer peripheral drive means consisting of a first outer peripheral mold drive means allowing the outer peripheral ring part 4 to slide in the direction approaching the fixed mold part 2 and a second outer peripheral mold drive means allowing the outer peripheral ring part 4 to slide in the direction spaced apart from the fixed mold part are provided. The second outer peripheral mold drive means uses the mold apparatus 1 provided to the fixed mold part 2 to mold the substrate of a disc-shaped recording medium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold apparatus for molding a disc-shaped recording medium substrate used when injection molding a substrate constituting a disc-shaped recording medium such as an optical disk with a synthetic resin material, and a molding die for the same. The present invention relates to a method for forming a disk-shaped recording medium substrate using a mold device.

[0002]

2. Description of the Related Art Disc-shaped recording media such as optical disks and magneto-optical disks are provided with a disk-shaped substrate formed of a synthetic resin material. The read-only optical disk has pits, which are minute concave portions arranged in a pattern corresponding to a predetermined information signal, on the surface of the above-described substrate, and has a reflective layer formed by evaporating aluminum or the like. In the magneto-optical disk, a pre-groove which is a concentric convex portion forming a recording track on which a desired information signal is recorded is formed on the surface of the substrate, and a signal recording layer having a magnetic film is formed. Have been.

A disk-shaped substrate constituting such a disk-shaped recording medium such as an optical disk is made of a synthetic resin such as a polycarbonate resin having a light transmitting property, and is mounted on an injection molding machine and used for forming a substrate shown in FIG. It is molded using the mold device 50.

As shown in FIG. 3, a substrate forming mold device 50 is disposed opposite to the fixed mold 51 and is fixed to the fixed mold 51. The movable mold 52 is provided so as to be detachable, and an annular outer mold 53 is provided on the movable mold 52. In the substrate molding die apparatus 50, a resin material is formed by the stamper 55 attached to the fixed mirror 54 of the fixed mold part 51, the movable mirror 56 of the movable mold part 52, and the outer peripheral mold 53. Is injected and filled to form a cavity 57.

[0005] The mold apparatus 50 for forming a substrate includes a movable mold 5.
A mold clamping step is performed in which the mold 2 moves close to the fixed mold 51, and the above-described cavity 57 is formed. Thereafter, the substrate molding apparatus 50 performs an injection step of injecting and filling a molten resin material into the cavity 57 from the material inlet 59 of the sprue bush 58 assembled to the fixed mold 51, A compression / cooling process is performed in which the movable mold 52 compresses the filled resin material closer to the fixed mold 51 and cools the resin material for a predetermined time. Then, an extraction step of removing the cooled and cured resin material from the substrate molding die device 50 is performed, and the substrate of the disk-shaped recording medium is molded.

In the substrate molding apparatus 50, since the resin material is injected into the cavity 57 at a high pressure, the pressure is applied to the fixed mold 51 and the movable mold 5 by the pressure.
2 may be separated. In the substrate forming mold device 50, when the fixed mold 51 and the movable mold 52 are separated from each other, the outer peripheral mold 53 disposed on the movable mold 52 is similarly separated from the fixed mold 51. I do.

As shown in FIG. 4, when the outer peripheral mold 53 for molding the outer peripheral portion of the substrate is separated from the fixed mold 51, a gap E is formed in the outer peripheral portion of the cavity 57 in the substrate molding die apparatus 50. In the substrate molding apparatus 50, when the resin material flows into the gap E and cures as it is, burrs are generated at the outer peripheral portion of the substrate.

For this reason, in the substrate molding die apparatus 50, the above-mentioned burrs are generated by slidably disposing the outer peripheral die 53 in the outer peripheral die storage portion 60 of the movable die 52. Has been prevented. Conventional substrate molding die apparatus 50
As shown in FIG. 3, the outer peripheral mold 53 is supplied and discharged by supplying compressed air from a compressor or the like (not shown) through an air flow path 61 opened on the bottom side of the outer peripheral mold housing section 60, for example. It is slidable in the directions of arrows C and D in the figure. Specifically, the substrate molding die apparatus 50 supplies compressed air into the outer peripheral die housing section 60 to cause the substrate molding die apparatus 50 to move in the direction of arrow C, that is, in the direction approaching the fixed-side die 51.
The compressed air is exhausted (vacuum) from the inside of the outer peripheral die housing section 60, so as to be in the direction of arrow D, ie, the fixed side die 5
By sliding the outer peripheral mold 53 in a direction away from the fixed mold 1, contact and separation with the fixed mold 51 are adjusted.

In addition, in the substrate molding die apparatus 50, in addition to the above-described configuration, as shown in FIG. 5, for example, a spring 62 urged in the direction of arrow C in FIG. Is disposed on the bottom surface 53a side of the outer peripheral mold 53, whereby the outer peripheral mold 53 is biased in the direction of arrow C to prevent separation from the fixed mold 51.

[0010]

In the conventional substrate molding apparatus 50, the sliding of the outer mold 53 in the direction of arrow C in FIG. 3 by the supply of compressed air is performed by the pressure of the compressed air. Since the force for pressing the mold 53 is strong, stable operation is possible. However, in the substrate molding die apparatus 50, the sliding in the direction indicated by the arrow D in FIG. 4 performed by the exhaustion has a weak force and easily loses balance, so that the operation of the outer peripheral die 53 is not stable. In the substrate molding die apparatus 50, when the operation stroke of the outer peripheral mold 53 is large, the operation of the outer peripheral mold 53 becomes more unstable, and the outer peripheral mold 53 may not slide at all. Further, while cooling the resin material in the substrate molding die apparatus 50, the outer peripheral die 5
In the case where 3 is slid in the direction of arrow D, the method of exhausting the compressed air from the outer mold housing section 60 may not be enough. For this reason, in the conventional substrate molding die device 50, there is a problem that the characteristics of the substrate to be molded vary and it cannot be stabilized.

Further, in the substrate molding die apparatus 50, the outer peripheral die 53 urged by the spring 62 can slide only in one direction, that is, in the urged direction of arrow C in FIG. There is no return mechanism for sliding in the direction of the arrow C. For this reason, in the substrate molding die device 50, the mold release resistance when the molded substrate is removed from the substrate molding die device 50 is increased by the outer peripheral die 53 urged in the arrow C direction. Then, there is a problem that the substrate is deformed.

Accordingly, the present invention provides a mold apparatus for molding a disc-shaped recording medium substrate which suppresses deformation and variations in characteristics of the molded substrate when the substrate of the disc-shaped recording medium is injection-molded with a resin material. It is an object of the present invention to provide a method for forming a disk-shaped recording medium substrate.

[0013]

According to the present invention, there is provided a mold apparatus for molding a disc-shaped recording medium substrate, which achieves the above object.
A fixed mold, a movable mold opposed to the fixed mold and detachably provided, and slidably provided in the movable mold in a direction to approach and separate from the fixed mold. Annular outer peripheral mold, first outer peripheral mold driving means for sliding the outer peripheral mold toward the fixed mold, and sliding in the direction for separating the outer peripheral mold from the fixed mold. And a second outer peripheral die driving unit comprising a second outer peripheral die driving unit, and the second outer peripheral die driving unit is provided on the fixed die side.

Further, according to the method of molding a disk-shaped recording medium substrate according to the present invention, a mold clamping operation is performed by moving the movable mold close to the fixed mold by using the molding mold apparatus having the above-described structure. Process, an injection process for filling the molten resin into the molding die apparatus, a cooling / compression process for compressing and cooling the filled molten resin, and a mold opening process for separating the movable mold from the fixed mold. And a step of removing the disk-shaped recording medium substrate from the molding die apparatus to form the disk-shaped recording medium substrate.

In the above-described mold apparatus for molding a disk-shaped recording medium substrate and the method of molding a disk-shaped recording medium substrate according to the present invention, the first and second outer-circle mold driving means provide a sufficient force to the outer peripheral mold. Can be slid in both directions toward and away from the fixed mold. Therefore, according to the molding apparatus for molding a disk-shaped recording medium substrate and the method of molding a disk-shaped recording medium substrate according to the present invention, when the substrate is injection-molded with a resin material, the characteristics of the substrate are stabilized, and The release resistance when the substrate is removed from the molding die apparatus by increasing the operation stroke of the die is reduced, and the deformation of the substrate is suppressed.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of a disk-shaped recording medium substrate molding apparatus and a disk-shaped recording medium substrate forming method according to the present invention will be described in detail with reference to the drawings. I do.

First, prior to the description of a molding apparatus for molding a disk-shaped recording medium substrate and a method of molding a disk-shaped recording medium substrate according to the present invention, a disk-shaped recording medium having a substrate molded by the apparatus and method will be described. explain. The disk-shaped recording medium includes an optical disk exclusively used for reproduction only and a magneto-optical disk capable of rewriting an already recorded information signal. The optical disk has pits, which are minute concave portions arranged in a pattern corresponding to a predetermined information signal, on the surface of the substrate, and has a reflective layer formed by evaporating aluminum or the like. In the magneto-optical disk, a pre-groove which is a concentric convex portion forming a recording track on which a desired information signal is recorded is formed on a surface of a substrate, and a signal recording layer having a magnetic film is formed. I have.

The molding die apparatus 1 according to the present embodiment comprises:
A substrate constituting the above-described disc-shaped recording medium is molded from a resin material. As shown in FIG.
A fixed mold part 2 and a movable mold part 3 which are arranged to face each other, and an outer peripheral ring part 4 which is arranged on the movable mold part 3
And is provided.

The fixed-side mold portion 2 is configured such that the other main surface of a fixed-side receiving plate 6 having a fixed-side mirror 5 provided on one main surface is mounted on a fixed-side mounting plate 7. The fixed-side mirror 5 has a principal surface facing the movable-side mold part 3 as a highly accurate smooth surface. The fixed-side mirror 5 has a stamper 8 attached to a main surface configured as a smooth surface.

The stamper 8 is formed in a disk shape having a center hole at the center, and has a fine concavo-convex pattern formed on the main surface facing the movable mold 3. The stamper 8 transfers and forms a pre-groove forming a pit or a recording track, which is a concavo-convex pattern corresponding to an information signal, on the surface of the substrate by the concavo-convex pattern. Stamper 8
As described later, the fixed-side mold portion 2 into which a resin material such as a high-temperature molten transparent polycarbonate resin is injected at a high pressure is used.
Is fixed to the main surface of the fixed side mirror 5 of the fixed side mold part 2 by a stamper holder (not shown) at the center hole and the outer peripheral portion.

A material inlet 9 for injection-filling a resin material in a molten state, for example, a transparent polycarbonate resin, which is provided at the center of the fixed-side mirror 5 and supplied from the injection molding machine at a high pressure, is provided in the fixed-side mold portion 2. Is mounted.

As shown in FIG. 1, a piston 11 is inserted through the fixed-side receiving member 6 from the fixed-side receiving plate 6 to the fixed-side mirror 5 so that the tip 11a projects toward the movable-side mold part 3. Are arranged. The piston 11 has its base 1
1b, a first flow path 13 and a second flow path 14 for supplying compressed air, which will be described later, are connected to an annular piston ring 12 disposed in a cylinder 15 having an opening. It is slidable in the B direction. Piston 1
1 are provided in plural numbers and are arranged at substantially equal intervals on the circumference of the piston ring 12. The piston 11 has a tip 11
a is disposed facing the outer peripheral ring portion 4 disposed on the movable mold portion 3.

The movable mold part 3 is provided so as to face the above-mentioned fixed mold part 2 and is configured to be able to contact and separate. The movable mold part 3 includes the fixed mold part 2 of the movable mounting plate 16.
A movable mirror 17 is provided on a main surface opposite to.
The movable-side mirror 17 has a main surface facing the fixed-side mold part 2 as a high-precision smooth surface, similarly to the fixed-side mirror 5.

An ejector sleeve driven by drive means (not shown) is provided at the movable mold part 3 at a position facing a substantially central portion of the movable mirror 17 facing the sprue bush 10 of the fixed mold part 2. 18, a punch 19 and an ejector pin 20 are slidably incorporated. The ejector sleeve 18 and the ejector pin 20 protrude toward the fixed mold section 2 by the driving means and are formed on the movable mirror 17 when the mold opening operation of the molding mold apparatus 1 is performed as described later. The substrate is pressed and detached from the movable mirror 17. The punch 19 is a sprue bush 1
A central hole is formed in the substrate by cutting and removing the central region of the substrate where the material inlet 9 of the substrate 0 is open.

The outer peripheral ring portion 4 is formed in an annular shape and is accommodated in an annular outer peripheral ring accommodation portion 21 formed between the movable mounting plate 11 and the movable mirror 12. The outer peripheral ring portion 4 includes a mold portion 4a which forms the outer peripheral surface of the substrate and has a center hole having the same diameter as the outer diameter of the substrate;
And a flange portion 4b formed integrally and overhanging.
The outer peripheral ring portion 4 has a width substantially equal to the width of the outer peripheral ring storage portion 21 and is slidably disposed in the directions of arrows A and B in FIG.

The outer ring portion 4 includes an outer ring storage portion 21.
A recess is formed over the entire outer periphery of the flange portion 4b in contact with the outer peripheral wall, and the sealing ring 22 is fitted into the recess. On the other hand, a concave portion is formed in the outer peripheral ring storage portion 21 over the entire circumference of the inner peripheral wall on the movable side mirror 17 side, and the sealing ring 23 is fitted in this concave portion. The outer ring portion 4 is configured as a space portion 24 in which the space between the outer ring portion 4 and the bottom surface of the outer ring storage portion 21 is sealed by the above-described sealing rings 22 and 23. This space 2
4, a third flow path 25 for supplying compressed air is opened as described later.

When compressed air is supplied to the space 24 via the third flow path 25 by a compressor (not shown), the outer peripheral ring 4 slides in the direction of arrow B in FIG. The sliding range of the outer peripheral ring portion 4 is regulated by the flange portion 4b abutting on a ring-shaped stopper 26 provided such that the inner peripheral portion slightly projects inward of the outer peripheral ring storage portion 21. ing.

In the molding die apparatus 1, when the movable mold part 3 approaches the fixed mold part 2 and the mold clamping step is performed as described later, a disk-shaped cavity 27 is formed therein. Is configured. The cavity 27 is constituted by the stamper 8 attached to the fixed mirror 5 of the fixed mold unit 2 described above, the movable mirror 17 of the movable mold unit 3, and the mold unit 4 a of the outer ring 4. By filling the inside with a molten resin, a disk-shaped recording medium substrate is formed.

Hereinafter, a method of forming a disc-shaped recording medium substrate using the molding die apparatus 1 having the above-described configuration will be described.

First, in the molding apparatus 1, a mold clamping step is performed in which the movable mold section 3 moves close to the fixed mold section 2. When the mold clamping step is performed, the molding die apparatus 1 forms the cavity 27 into which the molten resin is injected and filled via the sprue bush 10 as described above.

Next, the molding die apparatus 1 is provided with the material inlet 1 of the sprue bush 10 assembled to the fixed die 2.
An injection step of filling the molten resin into the cavity 27 from 1 is performed. In the molding apparatus 1, since the molten resin is filled into the cavity 27 at high pressure, the movable mold section 3 may be separated from the fixed mold section 2 during the injection process. For this reason, in the molding die apparatus 1, the compressor (not shown) is driven to drive the third flow path 25.
Compressed air is supplied to the space portion 24 of the outer ring storage portion 21 via. In the molding apparatus 1, the compressed air is supplied to the space 24 of the outer ring storage section 21 so that even when the movable mold section 3 is separated from the fixed mold section 2, the outer ring section 4 is kept. 1 is held in a state of sliding in the direction of arrow B in FIG. Therefore, in the molding apparatus 1, no gap is formed between the end face of the mold section 4 a of the outer peripheral ring section 4 and the fixed mold section 2, thereby preventing occurrence of burrs on the outer peripheral section of the substrate.

In the molding apparatus 1, when the cavity 27 is filled with the molten resin, the movable mold 3 is moved closer to the fixed mold 2 to compress the mold for a predetermined time. Then, a compression / cooling step of cooling is performed. The molding die apparatus 1 drives the punch 19 with respect to the resin in the cavity 27 that has undergone a compression operation in this compression / cooling step and has become semi-cured, thereby forming a center hole of the substrate.

Further, the molding die apparatus 1 terminates the supply of the compressed air to the third flow path 25 during the cooling operation or after the cooling operation is completed, and stops the supply of the compressed air to the first flow path 13. Start. As shown in FIG. 2, when the compressed air is supplied to the first flow path 13, the molding die apparatus 1 presses and slides in the cylinder 15 in the direction of arrow A in FIG. With piston 1
1 also slides in the direction of arrow A. In the molding die apparatus 1, as described above, the tip 11 a of the piston 11 is disposed facing the outer ring portion 4, so that when the piston 11 slides in the direction of arrow A, the tip 11 a becomes 4
, And slides in the same direction in the outer ring receiving portion 21 by pressing. At this time, since the molding apparatus 1 is pressed by the plurality of pistons 11 which are connected to the annular piston ring 12 at substantially equal intervals and operate uniformly, the outer peripheral ring portion 4 can slide in a well-balanced manner. .

In the molding die apparatus 1, at least the thickness of the substrate formed by the piston 11, specifically, the end surface of the die part 4 a of the outer peripheral ring part 4 is formed on the movable side forming the cavity 27. The outer ring 4 is slid until it is flush with the main surface of the mirror 17 or is located below the main surface of the movable mirror 17. At this time,
In the molding apparatus 1, although the operation stroke of the outer peripheral ring portion 4 is large, since the outer peripheral ring portion 4 is pressed by the uniform operation of the plurality of pistons 11 as described above, the sliding is performed with sufficient force and good balance. Can be moved.

Thereafter, the molding die apparatus 1 performs a mold opening step in which the movable mold part 3 is separated from the fixed mold part 2. In the molding apparatus 1, when the movable mold section 3 is separated from the fixed mold section 2, the molded and cured substrate is stuck to the movable mirror 17 by being compressed and cooled. It has become. For this reason, the molding die apparatus 1
Performs an unloading step in which the ejector sleep 18 and the ejector pin 20 are driven and the substrate is taken out of the apparatus after the opening amount between the fixed mold section 2 and the movable mold section 3 reaches a predetermined value. . At this time, in the molding die apparatus 1, the outer peripheral ring portion 4 is slid and held more than the thickness of the substrate as described above. For this reason, the molding die apparatus 1
In the above-described removal step, the substrate and the outer peripheral ring portion 4 do not come into contact with each other, so that the facing of the mold is reduced, so that a stable quality substrate with less deformation and variation in characteristics can be obtained.

After the above-described steps have been completed and the substrate has been formed, the molding die apparatus 1 repeats from the mold clamping step to form the substrate again. In the molding apparatus 1, after the substrate is formed, the supply of the compressed air to the first flow path 13 is cut off, and the supply of the compressed air to the second flow path 14 and the third flow path is stopped. Be started. Then, in the molding die apparatus 1, the piston 11 and the outer peripheral ring portion 4 are pressed and slid in the direction of arrow B in FIG. 2, and the state shown in FIG.

In the molding apparatus 1, the outer ring 4 is driven by using a compressor. However, the means for driving the outer ring 4 is not limited to the compressor. May be configured.

[0038]

As described above in detail, the mold apparatus for molding a disk-shaped recording medium substrate and the method for molding a disk-shaped recording medium substrate according to the present invention are characterized in that the outer peripheral mold is separated from the fixed mold. By providing the outer peripheral die driving means on the fixed die side separately from the first outer peripheral die driving means for bringing the outer peripheral die driving means close to the fixed die, the outer peripheral die can be moved to the fixed die with sufficient force. Can be slid in both directions. For this reason, according to the disk-shaped recording medium substrate molding die apparatus and the disk-shaped recording medium substrate molding method of the present invention, the operation of the outer peripheral die is stabilized, and the characteristics of the substrate to be molded are stabilized. Can be. Further, according to the molding apparatus for molding a disk-shaped recording medium substrate and the method for molding a disk-shaped recording medium substrate according to the present invention, it is possible to increase the moving stroke of the outer peripheral mold, and the molded substrate can be mounted on the apparatus. It is possible to reduce the release resistance at the time of detaching from the substrate, thereby suppressing deformation of the substrate and variation in characteristics.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a molding die apparatus in which an outer peripheral die is close to a fixed-side die portion.

FIG. 2 is a longitudinal sectional view of a molding die apparatus in which an outer peripheral die is separated from a fixed-side die portion.

FIG. 3 is a longitudinal sectional view of a conventional molding die apparatus having an air flow path.

FIG. 4 is an enlarged vertical sectional view of a main part of the molding die apparatus.

FIG. 5 is an enlarged longitudinal sectional view of a main part of another conventional molding die apparatus having a spring.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Molding apparatus for molding, 2 Mold part for fixed side, 3 Mold part for movable side, 4 Outer ring part, 11 piston, 12 piston ring, 13 1st flow path, 14 2nd flow path, 1
5 cylinders, 24 third channels, 27 cavities

Claims (4)

[Claims] 1. A fixed-side mold, a movable-side mold facing the fixed-side mold so as to be able to contact and separate from the fixed-side mold, and approaching and separating from the movable-side mold with respect to the fixed-side mold. An annular outer peripheral mold slidably provided in a direction in which the outer peripheral mold is moved, a first outer peripheral mold driving means for sliding the outer peripheral mold in a direction to approach the fixed mold, and a fixed mold. And a second outer peripheral mold driving means that slides in a direction to be separated from the outer peripheral mold driving means. A molding apparatus for molding a disc-shaped recording medium substrate, wherein 2. The second outer peripheral mold driving means includes: a plurality of pistons connected by an annularly formed piston ring; a cylinder in which the piston ring and the piston are disposed; 2. The apparatus according to claim 1, further comprising a drive mechanism for sliding the piston ring and the piston. 3. A fixed-side mold, a movable-side mold facing the fixed-side mold and provided so as to be able to approach and separate from the fixed-side mold, and approaching and separating the movable-side mold from the fixed-side mold. An outer peripheral mold slidably provided in a direction to be moved, first outer mold driving means for sliding the outer mold in a direction to approach the fixed mold, and a fixed mold. And a second outer peripheral mold driving means comprising a second outer peripheral mold driving means which slides in a direction to be separated from the second outer peripheral mold driving means. Using a provided mold device for molding a disc-shaped recording medium substrate, a mold clamping step of causing the movable mold to move closer to the fixed mold, and melting the molten resin into the mold device. An injection process for filling, a cooling / compression process for compressing and cooling the filled molten resin, and the movable mold A disc-shaped recording medium characterized by forming a disc-shaped recording medium substrate through a mold opening step of separating from the fixed mold, and a removal step of removing the disc-shaped recording medium substrate from the molding die apparatus. Substrate molding method. 4. In the removing step, the outer peripheral mold of the mold device for molding the disc-shaped recording medium substrate is separated from the fixed mold by a thickness not less than the thickness of the disc-shaped recording medium substrate. The method for forming a disc-shaped recording medium substrate according to claim 3, wherein: