JP3301103B2 - Die equipment for disk substrate molding - Google Patents

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 for molding a disk substrate for an optical disk 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 apparatus.

[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, a read-only optical disk that only reproduces an information signal recorded in advance and a rewritable magneto-optical disk that can rewrite an information signal once recorded are known. . The read-only optical disk has a reflective film formed by evaporating aluminum or the like on one main surface side of a disk substrate on which a so-called pit, which is a concavo-convex pattern corresponding to an information signal such as a predetermined tone signal, is formed. It is constituted by being provided. 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.

[0003] An optical disc of this kind can record an information signal such as a digitized tone signal at an extremely high density. Therefore, the applicant of the present application has proposed a device having a diameter of 64 mm and capable of recording and reproducing, or only reproducing, a tone signal of at least 74 minutes.

[0004] As shown in FIG.
A disk substrate 2 formed by molding a synthetic resin material such as a polycarbonate resin having a light transmitting property, and a perpendicular magnetization film is formed on one main surface of the disk substrate 2 on which a pre-groove forming a recording track is formed. To form a signal recording layer. The recording of the information signal on the optical disc 1 is emitted from the optical pickup onto a recording track provided in a signal recording section on which a signal recording layer is formed while the optical disc 1 is driven to rotate at a predetermined rotation speed. This is performed by irradiating a light beam and applying a magnetic field modulated in accordance with an information signal to be recorded from an external magnetic field generator.

Since the optical disk 1 has a small diameter and fine recording tracks formed at a high density, as shown in FIG. 10, the optical disk 1 is disposed in a disk recording and / or reproducing apparatus for rotating the optical disk 1. The disk rotation drive mechanism 3 to be installed is accurately positioned and mounted on the disk table 4, and is surely mounted integrally with the disk table 4, and is accurately synchronized with the rotation of the disk table 4. It needs to be driven to rotate.

Therefore, the center of the disk main body 2a, on which the signal recording layer of the disk substrate 2 forming the optical disk 1 is formed, on the side of the other main surface 2c facing the one main surface 2b, A protruding portion 8 having a mounting reference surface 7 for accurately determining the mounting height position is formed at the front end. The projection 8 has a centering member engaging hole 6 at the center thereof, which is engaged with a centering member 5 arranged at the center of rotation of the disk table 4 and for centering the optical disk 1 mounted on the disk table 4. It is formed by drilling and forming a ring. This centering member engaging hole 6 is
It is formed as a through hole communicating with a center hole 6a formed in the substrate body 2a.

On the one main surface 2b side of the disk substrate 2, a thin metal plate 9 made of a magnetic material is disposed so as to close the center hole 6a. The metal plate 9 is attracted by a magnet 10 disposed on the disk table 4 side, and is for integrating the optical disk 1 mounted on the disk table 4 with the disk table 4.

As shown in FIG. 10, the optical disc 1 thus configured has the centering member engaging hole 6 engaged with the centering member 5 and the mounting reference surface 7 formed at the tip of the projection 8 as shown in FIG. The disk table 4 is supported on the disk support surface 4a, and the metal plate 9 is
When the disc table 4 is mounted on the disc table 4 by suction, the center of the disc table 4 coincides with the center of rotation of the disc table 4 and the mounting height position is determined. Mounted on top.

Incidentally, the disk substrate 2 formed by molding a synthetic resin material such as a polycarbonate resin constituting the optical disk 1 is molded by a mold device for injection molding. A mold device for molding the disk substrate 2 includes:
A fixed mold and a movable mold that form a molding cavity corresponding to the disk substrate 2 are provided. For example, irregularities corresponding to information signals such as a predetermined tone signal are provided on the disk substrate molding surface of the fixed mold. A stamper for forming a so-called pit as a pattern or a pre-groove forming a recording track on which a desired information signal is recorded is arranged, and a centering member engaging hole 6 provided at the center of the projection 8 on the movable mold side. A punch is provided for punching.

The molding of the disk substrate 2 using the above-mentioned 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 the disk substrate 2 is formed in the forming cavity, the punching is moved to form a centering member engaging hole 6 at the center of the protrusion 8 and a pit is formed on one main surface side. Alternatively, the disk substrate 2 on which the pregroove is formed is formed.

[0011]

By the way, a stamper for forming a pit or a pre-groove formed on one main surface side of the disk substrate 2 has an inner peripheral side stamper holder and a lower peripheral side of a center hole. It is mounted on the disk forming surface side of the fixed mold or the movable mold supported by the outer stamper holder.

When the stamper is supported by the stamper retainer as described above, when the molten synthetic resin material is filled in the molding cavity, a part of the synthetic resin material enters between the stamper and the stamper retainer. As a result, burrs are generated on the formed disk substrate. In particular, when burrs are generated on the outer peripheral side stamper holding side, the release resistance becomes extremely large, and the molded disk substrate cannot be easily released from the stamper side. Also, if the release resistance becomes large and it becomes impossible to easily release the mold from the stamper side, a molding distortion is caused on the molded disk substrate, and polarization abnormalities and the like are generated. It can no longer be used.

Accordingly, the present invention provides an easy and reliable mold release of a disk substrate formed from a stamper for forming 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 that does not cause molding distortion or the like in a substrate.

[0014]

According to the present invention, in order to achieve the above-mentioned object, a pit or a pre-groove provided on a stamper is formed by molding a synthetic resin material on one surface side. In a mold device for molding a disk substrate for an optical disk having a projection integrally formed with a projection having a tip end surface as a mounting reference surface at a central portion on the other surface side, a fixed mold for forming a disk substrate molding cavity. A movable mold that is disposed opposite to the fixed mold and forms a disk substrate molding cavity together with the fixed mold;
A stamper attached to one of the fixed mold and the movable mold, and a position corresponding to an outer peripheral edge side of a substrate main body on which a mold on a side different from the side to which the stamper is attached is formed. Is provided with a release resistance portion.

The present invention further provides a release resistance portion at a position corresponding to the outer peripheral surface of a projection integrally formed on a disk substrate on which a mold is formed on a side different from the side on which the stamper is mounted. ing.

In the present invention, a punch for forming a through hole provided at the center of the protrusion of the disk substrate is provided on the side of the mold on which the release resistor is provided.

[0017]

According to the present invention, there is provided a die apparatus for molding a disk substrate.
After forming the disk substrate, when the mold opening is performed to move the movable mold in the direction away from the fixed mold, the mold disc is regulated in the mold release direction by the mold release resistor, and the fixed mold is opened. Release from a stamper mounted on a mold or a movable mold is performed.

The recess or protrusion corresponding to the mold release resistor formed by the mold release resistor is formed on the outer peripheral surface of the protrusion of the disk substrate to be molded or the outer peripheral side of the substrate main body. The influence on the mounting reference surface formed at the tip of the portion and the main surface of the disk substrate on which pits and pregrooves are formed is prevented.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a mold apparatus for molding a disk substrate according to the present invention. As shown in FIG. 1, the disk substrate forming die apparatus includes a fixed side die 21 and a movable side supported via a hydraulic mechanism or the like so as to be able to advance and retreat in a direction approaching and leaving the fixed side die 21. A mold 23 including the mold 22 is provided. This mold 23
The molding cavity 24 corresponding to the disk substrate 2 to be molded as shown in FIG.

On the fixed mold 21 side, a synthetic resin material such as a molten polycarbonate resin supplied from an injection molding machine is placed in the molding cavity 24 at the center of the molding cavity 24. A sprue bush 25 for inflow is provided. This sprue bush 25
A resin injection nozzle 26 is bored at the center of the mold, and a molten synthetic resin material supplied from an injection molding machine is injected into the molding cavity 24 through the resin injection nozzle 26.

On the outer peripheral side of the sprue bush 25, a holder support 27 to which an inner peripheral stamper holder for supporting an inner peripheral side of a stamper described later is fitted is disposed. The other main surface 2c of the disk substrate 2 is provided on the tip end side of the holder support 27 projecting into the molding cavity 24.
On the side, a protrusion forming portion 28 is formed so as to form a protrusion 8 having a mounting reference surface 7 formed on the distal end surface and having a thickness substantially the same as the thickness of the substrate body 2a.

On the molding surface 21a defining the molding cavity 24 of the fixed mold 21, so-called pits, which are minute concave / convex patterns corresponding to information signals recorded on the optical disk 1, or the optical disk 1 A stamper 29 for forming a pre-groove forming a recording track formed in the signal recording section is mounted. The stamper 29 has a peripheral edge of the center hole 30 supported by an inner peripheral side stamper retainer 31 fitted and disposed on the holder support 27 and an outer peripheral side disposed on an outer peripheral side of the fixed mold 21. The fixed side mold 21 is mounted on the molding surface 21 a side of the fixed side mold 21 while being supported by the stamper retainer 32.

On the other hand, in the center of the movable mold 22 on the molding surface 22a side defining the molding cavity 24, the disk substrate 2 is cooperated with the projection molding section 28 provided on the fixed mold 21. A projection forming recess 33 for forming the projection 8 projecting from the other main surface 2c is formed. A punching punch 34 of a punching punch mechanism for punching and forming a centering member engaging hole 6 formed as a through hole at the center of the protrusion 8 is provided at the center of the protrusion forming concave portion 33. The punch 34 is disposed on the movable mold 22 so as to advance and retreat in the sleeve 35.

It should be noted that the above-mentioned sleeve 35 is
The disc substrate 2 is supported so as to be able to advance and retreat with respect to the movable die 2 and is pushed out from the movable mold 22.

On the outer peripheral side of the movable mold 22, the outer peripheral side of the molding cavity 24 is defined.
A disk outer peripheral surface forming member 36 for forming the outer peripheral side peripheral surface of the disk substrate 2 to be molded is provided. This disk outer peripheral surface forming member 36 has a smooth end surface 3
6a, and is disposed so as to be located on the inner peripheral side of the outer stamper retainer 32 attached to the fixed mold 21. When the movable-side mold 22 is moved to the fixed-side mold 21 in the mold-clamped state, the disk outer peripheral surface forming member 36 comes into contact with the smooth abutting surface 36a against the stamper 29 to form the molding cavity 24. Is sealed, the occurrence of voids on the outer peripheral side of the molding cavity 24 into which the molten synthetic resin material filled in the molding cavity 24 enters is reliably prevented, and the disk substrate 2 to be molded is formed. It prevents the occurrence of burrs and the like on the outer peripheral side.

The molding surface 22a of the movable mold 22 is
A mirror surface having a smooth surface with high precision so that the other main surface 2c of the disk substrate 2 on the light beam incident surface side of the disk substrate 2 and having a smooth surface with high accuracy can be formed; It has been done.

As shown in FIG. 2, on the inner peripheral surface of the projection forming recess 33 formed in the movable mold 22, a projection is provided on the other main surface 2 c side of the disk substrate 2 to be formed. An engagement projection 37 is provided to project and engage with the outer peripheral surface of the projection 8 to be engaged. That is, when the engaging projection 37 is opened after moving the movable mold 22 in the direction away from the fixed mold 21 after molding the disk substrate 2, the projection 8 of the disk substrate 2 is opened. And a release resistance portion which is engaged with the outer peripheral surface of the movable mold 22 and is held on the movable mold 22 side. A plurality of the engagement projections 37 are provided at predetermined intervals on the inner peripheral surface of the projection forming recess 33, or are formed in a ring shape.

The engaging protrusion 37 is formed from the bottom surface of the protrusion forming recess 33 so as not to affect the formation of the mounting reference surface 7 formed on the distal end surface of the protrusion 8 of the disk substrate 2. It is provided at a position on the inner peripheral surface that is separated.

Further, the molding cavity 24 of the disk outer peripheral surface forming member 36 disposed on the outer peripheral side of the movable mold 22.
The outer peripheral surface 2d of the disk substrate 2 to be molded also protrudes into and engages with the outer peripheral surface 2d of the disk substrate 2, and when the disk substrate 2 is molded and the mold is opened, the disk substrate 2 is moved to the movable side. Engagement protrusion 3 serving as a release resistance portion held on mold 22 side
8 are protruded. A plurality of the engagement protrusions 38 are provided on the inner peripheral surface of the disk outer peripheral surface forming member 36 at predetermined intervals, or are formed in a ring shape.

In order to mold the disk substrate 2 using the above-configured mold apparatus, the movable mold 22 is brought into a mold-clamped state close to the fixed mold 21 side. In this clamped state, the resin injection port 2 of the sprue bush 25
6, a synthetic resin material such as a molten polycarbonate resin supplied from an injection molding machine is injected into the molding cavity 24. At this time, punch 3
The centering member engaging hole 6 is formed at the center of the protrusion 8 by moving the moving member 4. Next, the movable mold 22 is fixed to the fixed mold 2.
The disk substrate 2 corresponding to the molding cavity 24 is formed by moving to the first side, performing mold clamping for compressing the synthetic resin material filled in the molding cavity 24, and performing cooling.

By the way, when the synthetic resin material is molded, the disk substrate 2 on which the engagement projection 37 projecting from the inner peripheral surface of the projection molding recess 33 formed in the movable mold 22 is molded. The engaging projection 38 projecting from the inner peripheral surface of the disk outer peripheral surface forming member 36 on the molding cavity 24 side is engaged with the outer peripheral surface 2d of the substrate body 2a. State. Here, the movable mold 22 is fixed to the fixed mold 2.
When the mold is opened to move in a direction away from the disk 1, the molded disk substrate 2 is brought into contact with the engaging projections 37 and 38.
And is released from a stamper 29 disposed on the fixed mold 21 following the movable mold 22.

Therefore, each of the engaging projections 37 and 38 is
The height and size are set so as to have a release resistance larger than the release resistance of the stamper 29 disposed on the fixed mold 21 of the disk substrate 2. By providing the engagement protrusions 37 and 38 in this manner, the molded disk substrate 2 is reliably released from the stamper 29 side,
It can be reliably moved to the movable mold 22 side where the stamper 29 is not provided.

Then, as described above, the disk substrate 2 formed by the mold apparatus provided with the engaging projections 37 and 38 is formed.
As shown in FIG. 4, a concave groove 8 a is formed as a detachable resistance portion corresponding to the engaging protrusion 37 of the protrusion 8. The concave groove 8 a is formed on the outer peripheral surface of the protrusion 8. Since it is formed, it is possible to form it with high precision and smooth without generating burrs and the like on the mounting reference surface 7 at the tip end surface which needs to be formed with high precision as a smooth surface.

The main body 2a of the disk substrate 2 has an engaging projection 38 provided on the disk outer peripheral surface forming member 36.
A concave groove 2e as a part to be separated is formed, and the concave groove 2e is formed in the substrate main body 2a as shown in FIG.
The signal recording portion is formed on the outer peripheral surface 2d which is the outer peripheral edge where the signal recording portion is not formed, so that the influence on the substrate body 2a on which the signal recording portion is formed can be suppressed.

Further, in the mold apparatus shown in FIG.
The punching punch 34 is arranged on the movable mold 22 side where the protrusion forming concave portion 33 for forming the mounting reference surface 7 formed on the tip end surface of the protrusion 8 is formed. A centering member engaging hole 6 protruding in the direction indicated by arrow A in FIG. Therefore, the mounting reference surface 7 can be formed into a high-precision smooth surface without generating punching burrs by the punch 34 on the mounting reference surface 7 side, and the centering member 5 of the centering member engaging hole 6 can be formed.
Can be molded with high precision.

In the above-described embodiment, the engaging projections 37 and 38 are provided on the inner peripheral surface of the projection forming concave portion 33 and the inner peripheral surface of the disk outer peripheral surface forming member 36, respectively. If a release resistance greater than the release resistance from the fixed-side mold 21 provided can be ensured, only one of them may be provided.

Further, in the above-described embodiment, the engagement protruding toward the disk substrate 2 formed on the inner peripheral surface of the protrusion forming concave portion 33 and the inner peripheral surface of the disk outer peripheral surface forming member 36 as a release resistance portion. Although the projections 37 and 38 are provided, it is preferable that the projections 37 and 38 can provide release resistance when the disk substrate 2 is released.
Therefore, as shown in FIG. 7, an engaging recess 41 is formed on the inner peripheral surface of the projection forming recess 33 so that a part of the outer peripheral surface of the projection 8 of the disk substrate 2 swells and engages. As shown in FIG. 8, an engagement concave portion 42 may be provided on the inner peripheral surface of the disk outer peripheral surface forming member 36 so that a part of the outer peripheral surface of the substrate main body 2a swells and engages.

Further, an engaging recess 41 is provided on the inner peripheral surface side of the protrusion forming concave portion 33, and an engaging protrusion 38 is provided on the inner peripheral surface of the disk outer peripheral forming member 36.
3 may be provided with an engagement protrusion 37 on the inner peripheral surface side, and an engagement concave portion 42 may be provided on the inner peripheral surface of the disk outer peripheral surface forming member 36.

In each of the above embodiments, the side on which the stamper 29 is mounted is the fixed-side mold 21 and the side on which the punch 34 is disposed is the movable-side mold 22. The configuration may be reversed.

[0040]

As described above, the disk substrate molding die apparatus according to the present invention is characterized in that the fixed or movable die on the side opposite to the side on which the stamper is provided is provided with the substrate main body to be molded. Since the release resistance part is provided at the position corresponding to the outer peripheral edge side, after forming the disk substrate, when the mold opening that moves the movable mold in the direction away from the fixed mold is performed, the mold release resistance part Since the release direction of the molded disk substrate is regulated, it is possible to reliably release the disk substrate from the mold side where the stamper having a large release resistance is disposed, and to prevent a release failure. In addition, it is possible to form the disk substrate without causing molding distortion and the like, and it is possible to easily remove the formed disk substrate from the mold.

Since the release resistance portion is provided at a position corresponding to the outer peripheral edge of the substrate body to be molded, the disk substrate is supported on the outer peripheral side having the largest diameter, and the stamper is securely disposed in a stable state. Can be released from the mold side.

Further, by providing a release resistance portion at a position corresponding to the outer peripheral surface of the projection integrally formed on the disk substrate, both the outer peripheral side and the inner peripheral side of the disk substrate are provided by the release resistance portion. By being supported, the mold can be more stably and surely released from the mold side where the stamper is arranged.

In particular, a so-called pit, which is a minute concavo-convex pattern corresponding to an information signal, or a pre-groove forming a recording track formed in a signal recording portion of an optical disk is formed on one principal surface side by a stamper, and the other is formed. A stamper is fixed when a disc substrate is formed, which has a through hole on the main surface side with which a centering member punched by a punching punch engages, and a protrusion with a smooth mounting reference surface on the tip end surface. By mounting the punch on the movable mold that is mounted on the side mold device and molding the mounting reference surface, and by setting the mold release direction of the disk substrate by the mold release resistor to the movable mold, Realization of reliable release of the molded disk substrate from the stamper and molding of the disk substrate without punching burrs on the mounting reference surface It can be carried out.

An optical disk constituted by using a disk substrate formed without generating burrs on the mounting reference surface side as described above is accurately positioned on a disk table of a disk rotation drive mechanism, and accurately positioned by a centering member. The centering is achieved and it can be mounted.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a disk substrate molding die apparatus according to the present invention.

FIG. 2 is a partial cross-sectional view showing an engagement protrusion constituting a release resistance portion formed on an inner peripheral surface of a protrusion forming recess.

FIG. 3 is a partial cross-sectional view showing an engagement protrusion forming a release resistance portion formed on the inner peripheral surface of the disk outer peripheral surface forming member.

FIG. 4 is a partial cross-sectional view showing a protruding portion of a disk substrate formed by the disk substrate forming die apparatus.

FIG. 5 is a partial perspective view showing an outer peripheral portion of a substrate body of a disk substrate formed by the disk substrate forming die apparatus.

FIG. 6 is a schematic cross-sectional view showing a state in which a centering member engaging hole is punched out of a projection of a disk substrate by a punching punch arranged in the disk substrate molding die apparatus.

FIG. 7 is a partial cross-sectional view showing another example of the release resistance portion formed on the inner peripheral surface of the projection-forming concave portion.

FIG. 8 is a partial cross-sectional view showing another example of the release resistance portion formed on the inner peripheral surface of the disk outer peripheral surface forming member.

FIG. 9 is a partially cutaway perspective view showing an optical disk configured using a disk substrate formed by molding a synthetic resin material.

FIG. 10 is a cross-sectional view showing a state where the optical disk is mounted on a disk rotation drive mechanism.

[Explanation of symbols]

2 disc substrate, 6 centering member engaging hole,
7 mounting reference plane, 8 protrusions, 21 fixed mold, 2
2 Movable mold, 24 Mold cavity, 29
Stamper, 33 protrusion forming concave portion, 34 punch for punching centering member engaging hole, 36 disk outer peripheral surface forming member, 37, 38 engaging protrusion forming a release resistance portion

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 45/00-45/84 B29C 33/00-33/76 G11B 7/26

Claims (3)

(57) [Claims] A pit or a pre-groove provided on a stamper is transferred to one surface of a synthetic resin material, and a protrusion having a front end surface as a mounting reference surface is provided at the center of the other surface. A molding apparatus for molding a disk substrate for an optical disk, which is integrally provided with a fixed side mold that constitutes a disk substrate molding cavity; A movable mold forming a disk substrate molding cavity together with the mold, and a stamper attached to one of the fixed mold or the movable mold, which is different from a side to which the stamper is attached. A disk substrate molding die device for an optical disk, comprising a release resistor provided at a position corresponding to the outer peripheral side of the substrate body on which the side die is molded. 2. A mold release resistance portion is provided at a position corresponding to an outer peripheral surface of the projection integrally formed on the disk substrate on which a mold on a side different from the side on which the stamper is mounted is formed. The mold apparatus for molding a disk substrate for an optical disk according to claim 1, wherein: 3. A punch for forming a through hole provided at the center of the projection of the disk substrate on the side of the mold on which the release resistor is provided.
Or a mold apparatus for molding a disc substrate for an optical disc according to 2.