JPH09314563A - Mold device for molding disklike recording medium substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold device for molding a disklike recording medium substrate in which a warpage and a projection are not caused in molding the disklike recording medium substrate. SOLUTION: The mold device for molding a disklike recording medium substrate is equipped with a stationary mold 3 forming the main surface on one side of a disk substrate 2, a movable mold 4 which forms the main surface on other side of the disk substrate 2 and also is freely detachably arranged for the stationary mold 3, an outer peripheral mold 5 for forming the outer peripheral face of the disklike recording medium substrate and for constituting a cavity 6 which is filled with synthetic resin material 7 by the stationary mold 3 and the movable mold 4, a first temperature controlling mechanism 20 performing temperature control of the stationary mold 3, a second temperature controlling mechanism 25 performing temperature control of the movable mold 4 and a third temperature controlling mechanism 30 performing temperature control of the outer peripheral mold 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold device for molding a disk-shaped recording medium substrate which constitutes a disk-shaped recording medium such as an optical disk, a magneto-optical disk, a magnetic disk or the like.

[0002]

2. Description of the Related Art Discotic recording media such as optical discs, magneto-optical discs, and magnetic discs have been provided which use a disc substrate molded of a synthetic resin material having a light-transmitting property such as a polycarbonate resin. The optical disc is configured by forming pits, which are minute recesses arranged in a pattern corresponding to a predetermined information signal, on the surface of a disc substrate, and forming a reflective layer by evaporating aluminum or the like. Further, in a magneto-optical disk, a pre-groove, which is a concentric convex portion that constitutes a recording track on which a desired information signal is recorded, is formed on the surface of a disk substrate, and a signal recording layer having a magnetic film is formed. There is. Further, in a magnetic disk, in particular, a magnetic disk built in a hard disk device used in a computer system, concentric circular convex portions forming recording tracks on which desired information signals are recorded are formed on the surface of a disk substrate. A signal recording layer having a magnetic film is formed. Further, in these disc-shaped recording media, it is possible to record a large amount of information signals on the disc-shaped recording medium by narrowing the intervals of the irregularities provided on the disc-shaped recording medium substrate and providing more irregularities.

A disk substrate molding die unit 50 is shown in FIG.
As shown in the figure, the fixed mold 51, a movable mold 52 which is disposed to face the fixed mold 51 and is moved in and out by a hydraulic mechanism, and an outer peripheral mold 53. The fixed mold 51 and the movable mold 52 form the respective main surfaces of the disk substrate to be molded, and the outer peripheral mold 53 forms the outer peripheral surface of the disk substrate to be molded. The fixed mold 51, the movable mold 52, and the outer peripheral mold 53 define a cavity 54 in which the synthetic resin material 55 is injected and filled. Further, in the disk substrate molding die apparatus 50, a synthetic resin material 55 is injected and filled into the cavity 54 at a high pressure in a state where the movable die 52 is moved closer to the fixed die 51 and clamped. Fixed mold 51
There is a sprue bush nozzle provided on the side.

[0004] A fixed mold 51 is provided with a cavity 54.
The stamper 56 (56a, 56b) having a minute concave and convex pattern formed on the main surface is attached to the side surface portion constituting the. Therefore, on the main surface of the disk substrate molded in the cavity 54, a fine concavo-convex pattern of the stamper 56 is transferred and formed to form pits corresponding to the information signal and pregrooves forming the recording portion of the information signal. To be done. After a predetermined cooling time has elapsed, the movable die 52 is moved away from the fixed die 51 to open the die, and the disk substrate formed from the cavity 54 is taken out. It is.

On the other hand, on the movable die 52 side, a punch for forming a center hole in the center of the disc substrate and an eject member for releasing the disc substrate are provided. The eject member is configured as a cylindrical member that is disposed in the movable mold 52 so as to be movable forward and backward corresponding to the central area where the information signal of the disk substrate is not recorded, and a punch is incorporated therein so as to be movable forward and backward in the axial direction. ing. When the synthetic resin material 55 filled in the cavity 54 is in a semi-molten state, the punch is projected into the cavity 54 to form a center hole in the disk substrate.

[0006] In order to prevent the occurrence of molding distortion of the disk substrate to be molded, the disk substrate molding mold device 50 moves the movable mold 52 closer to the fixed mold 51 after the center hole is drilled. In the state where the synthetic resin material 55 is compressed in this way, compression forming is performed by cooling and hardening using a temperature control device provided in the fixed mold 51 and the movable mold 52. After the elapse of a predetermined cooling period, the disk substrate molding mold device 50
A mold opening operation is performed with the molded disk substrate attached to the movable mold 52 side. The disk substrate is ejected from the movable mold by the ejecting member that is ejected, and taken out by the ejecting device.

[0007]

However, in the disk substrate molding die device 50, as described above, the temperature adjusting device is attached to the outer peripheral die 53 which forms the outer peripheral surface of the disk substrate to be molded. There wasn't. Therefore, the temperature of the outer peripheral die 53 becomes lower than the temperatures of the other fixed die 51 and the outer peripheral die 52. Therefore, as shown in FIG. 6, the outermost peripheral portion of the disk substrate 57 has a cavity 54.
The temperature of the synthetic resin material 55 filled in the vicinity of the outer peripheral die 53 decreases first to become the low temperature synthetic resin material 59, whereas the central area becomes the high temperature synthetic resin material 60. The molded disk substrate 57 is taken out from the cavity 54 by the take-out device, and then the high temperature synthetic resin material 60 in the central region is cooled and contracted. However, the low temperature synthetic resin material 59 in the vicinity of the outer peripheral portion of the disk substrate 57 has already been cooled and does not shrink as compared with the high temperature synthetic resin material 60. Therefore, as shown in FIG. 7, the disk substrate 57, which is a molded product, may have protrusions 58 at the outer peripheral edge, that is, the outermost peripheral portion.

Particularly, when the disk substrate 57 is used for a magnetic disk built in the hard disk device used in the computer system described above, a magnetic head for applying a magnetic field to a predetermined portion of the magnetic disk forms the disk substrate 57. In some cases, the magnetic head may be damaged by colliding with the projections 58 that sometimes occur. That is, in the magnetic disk used in the hard disk device, the intervals of the recording tracks are extremely high in order to achieve high capacity of the recorded information signal. Therefore, since the magnetic head steadily applies a magnetic field to the recording track of the magnetic disk to record an information signal, the magnetic head is arranged very close to the magnetic disk with a flying height of about 50 nm from the magnetic disk. Therefore, since the magnetic head records an information signal on a predetermined recording track, when the magnetic head slides in the radial direction of the magnetic disk or due to some vibration, it may collide with the protrusion 58 generated during the molding of the magnetic disk and be damaged. Further, since the magnetic heads are arranged in close proximity to each other, this magnetic disk is required to have extremely high accuracy in manufacturing.

When the disk substrate 57 is used for a magneto-optical disk, the gap between the magneto-optical disk and the magnetic head becomes too large to prevent the projection 58 from colliding with the magnetic head, and the optical disk is steadily lighted. In some cases, the magnetic field cannot be applied to the magnetic disk.

Therefore, the protrusion 5 formed on the disk substrate 57.
As a means for eliminating 8, the method of cutting off the outer peripheral side of the disk substrate 57 having the projection 58 after the molding of the disk substrate 57 is proposed. However, the method of cutting the outer peripheral side of the disk substrate 57 in which the protrusion 58 is generated causes a problem of increasing the manufacturing process of the disk substrate 57 and increasing the production cost.

Therefore, an object of the present invention is to provide a molding apparatus for molding a disk-shaped recording medium substrate which does not cause a protrusion at the outermost peripheral portion when the disk-shaped recording medium substrate is molded.

[0012]

DISCLOSURE OF THE INVENTION In order to solve the above-mentioned problems, a molding device for molding a disk-shaped recording medium substrate according to the present invention is fixed to form one main surface of the disk-shaped recording medium substrate. A mold and a movable mold, which forms the other main surface of the disk-shaped recording medium substrate and is arranged so that it can be brought into contact with and separated from the fixed mold, and an outer peripheral surface of the disk-shaped recording medium substrate, which is fixed. An outer peripheral mold defining a cavity filled with a resin material by the mold and the movable mold, a first temperature adjusting unit for adjusting the temperature of the fixed mold, and a second temperature adjusting unit for adjusting the temperature of the movable mold. Third temperature control means and third temperature control for the outer peripheral mold
Temperature adjusting means. The first temperature adjusting means, the second temperature adjusting means, and the third temperature adjusting means are characterized by independently adjusting the temperatures of the fixed mold, the movable mold, and the outer peripheral mold.

In the mold apparatus for molding the disk-shaped recording medium substrate having the above-mentioned structure, the fixed mold has the first temperature adjusting means, the movable mold has the second temperature adjusting means, and the outer peripheral metal mold. Since the mold is provided with the third temperature adjusting means, the temperature of each mold is adjusted independently, and the resin material in the cavity is uniformly cooled. Therefore, the disk-shaped recording medium substrate is molded without the resin material in the cavities being uniformly shrunk, and without causing the molding distortion that occurs when the disk-shaped recording medium substrate is molded.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A mold apparatus for molding a disk-shaped recording medium substrate according to the present invention will be described in detail below with reference to the drawings.

This disk-shaped recording medium substrate molding die device is applied as a disk substrate molding die device for manufacturing a disk substrate for a magnetic disk incorporated in a hard disk device used in a computer system, for example. This disk substrate molding die device 1 is shown in FIG.
As shown in FIG. 3, a fixed mold 3 that forms one main surface of the disk substrate 2, a movable mold 4 that is arranged to face the fixed mold 3 and forms the other main surface, and a disk substrate. 2 and an outer peripheral die 5 forming an outer peripheral surface.

The movable mold 4 is supported by guide means (not shown) and is moved into and out of contact with the fixed mold 3 by a drive mechanism, and the outer peripheral mold 5 is incorporated in the movable mold 4. Then, the fixed mold 3, the movable mold 4, and the outer mold 5
Form a cavity 6 which cooperates to form the disk substrate 2 in the mold clamped state. Then, the cavity 6 is filled with a synthetic resin material 7 which is a material of the disk substrate 2.

Further, in the fixed mold 3 and the movable mold 4, the stampers 8 (8a, 8a) are formed on the molding surface side forming the cavity 6.
b) is attached. The stamper 8 has a disc shape with a diameter larger than the outer diameter of the disc substrate 2, and
A center hole, which is slightly larger than the inner diameter of the center hole of the disk substrate 2, is formed. The stamper 8 has a concentric concavo-convex pattern forming a recording track for recording an information signal on the magnetic disk on one main surface thereof. Then, the stamper 8 transfers and forms this uneven pattern on the disk substrate 2. The stamper 8 is held by stamper holders (not shown) attached to the inner peripheral side and the outer peripheral side of the fixed mold 3 and the movable mold 4, respectively.

On the fixed mold 3 side, located at the center of the cavity 6 for molding the disk substrate 2, a polycarbonate resin or a polyolefin resin melted at about 300 ° C. supplied from an injection molding machine whose details are omitted. A sprue bush 11 having a nozzle 10 for injecting and filling a synthetic resin material 7 such as And
The synthetic resin material 7 supplied from the injection molding machine is injected and filled at high pressure into the cavity 6 through the nozzle 10.

On the other hand, the movable mold 4 has a first eject member 15 provided at a position corresponding to the center of the cavity 6.
Are movably arranged in the axial direction. The first ejecting member 15 is formed in a cylindrical shape having an outer diameter corresponding to an area on the inner peripheral side of the disk substrate 2 to be formed where the information signal is not recorded, and is shown when the disk substrate 2 is released. The disk substrate 2 protruded into the cavity 6 by the drive means not formed is protruded from the movable mold 4 and released.

A punch 13 is attached to the first eject member 15 for forming a center hole of the disk substrate 2 formed on the inner peripheral side thereof. This punch 13
It is moved in the same axial direction as the first ejection member 15 by a drive mechanism (not shown). And this punch 13
Is driven into the cavity 6 by this drive mechanism to form a center hole in the center cutting region of the disk substrate 2.

On the inner peripheral side of the punch 13, a second
The eject member 12 is attached by a hydraulic mechanism whose details are omitted so that the eject member 12 can move back and forth. The end surface of the second eject member 12 on the side of the cavity 6 constitutes the bottom surface of the resin reservoir 14. The second ejecting member 12 is disposed movably in the axial direction, similarly to the first ejecting member 15. Therefore, the synthetic resin material 7 injected and filled from the injection port of the nozzle 10 is injected toward the bottom of the resin reservoir 14, that is, the end face of the second eject member 12, and is uniformly filled in the cavity 6. . Then, after the center hole of the disk substrate 2 is formed by the punch 13, the second eject member 12 protrudes the synthetic resin material 7 in the cut area from the movable mold 4 to release the mold.

Further, the outer peripheral die 5 is fixed to the outer peripheral side of the movable die 4 by a set screw 16. The outer peripheral die 5 forms the outer peripheral surface of the disk substrate 2 to be molded.

In the disk substrate molding die apparatus 1 having the above-mentioned structure, for example, as shown in FIGS. 1 to 4, the fixed mold 3 is provided with the first temperature adjusting mechanism 20 and the movable mold 4 is provided with the first temperature adjusting mechanism 20. The second temperature adjusting mechanism 25 is provided with the third temperature adjusting mechanism 30 on the outer peripheral mold 5, and adjusts the temperature of each of the molds 3, 4, and 5. These temperature control mechanisms 20, 25, 3
0 cools the synthetic resin material 7 filled in the cavity 6 and adjusts the temperature of each of the molds 3, 4 and 5 independently.

As shown in FIG. 3, the first temperature control mechanism 20 includes a temperature control section 21 for controlling the temperature of the fixed mold 3,
A cooling groove 22 which is recessed in a ring shape in the fixed mold 3 by the temperature adjusting part 21 to adjust the temperature, and a connection provided in a hole shape in the fixed mold 3 connecting the temperature adjusting part 21 and the cooling groove 22. And a pipe 23. Specifically, the temperature of the fixed mold 3 is controlled by 110 ° C. to 1 ° C. supplied from the temperature controller 21.
Liquid of about 20 ° C. is passed through the connecting pipe 23 to the fixed mold 3
The liquid is supplied to the cooling groove 22 disposed inside the cooling groove 22, and the liquid circulates in the cooling groove 22 to cool the fixed mold 3 to cool the synthetic resin material 7 in the cavity 6.

The second temperature adjusting mechanism 25, as shown in FIG. 4, controls the temperature of the movable mold 4 by the temperature adjusting section 2.
6, a cooling groove 27 provided in the movable mold 4 in a ring shape for temperature control by the temperature control section 26, and the temperature control section 2
6 and a connection pipe 28 provided in the movable mold 4 in a hole shape for connecting the cooling groove 27. Specifically, the temperature of the movable mold 4 is controlled by the temperature controller 11 supplied from the temperature controller 26.
A liquid of about 0 ° C. to 120 ° C. is supplied to the cooling groove 27 arranged inside the movable mold 4 through the connection pipe 28,
By circulating the liquid in the cooling groove 27, the movable mold 4 is cooled, so that the synthetic resin material 7 in the cavity 6 is cooled.

Further, as shown in FIG. 4, the third temperature adjusting mechanism 30 includes a temperature adjusting section 31 for controlling the temperature of the outer peripheral die 5 and a ring shape on the outer peripheral die 5 by the temperature adjusting section 31. A cooling groove 32 which is recessed to adjust the temperature, and a connection pipe 33 which is provided in a hole shape in the outer peripheral die 5 for connecting the temperature adjusting portion 31 and the cooling groove 32. More specifically, the temperature of the outer peripheral die 5 is controlled by a cooling groove in which the liquid of about 110 ° C. to 120 ° C. supplied from the temperature adjusting part 31 is arranged inside the outer peripheral die 5 via the connection pipe 33. When the liquid is supplied to the cooling groove 32 and the liquid circulates in the cooling groove 32, the outer peripheral die 5 is cooled, and thus the synthetic resin material 7 in the cavity 6 is cooled.

The first, second, and third temperature adjusting mechanisms 20, 25, 30 independently adjust the temperatures of the fixed mold 3, the movable mold 4, and the outer peripheral mold 5. . Therefore, the synthetic resin material 7 has a property of shrinking when cooled, but the synthetic resin material 7 filled in the cavity 6 is uniformly shrunk when cooled.

The first, second and third temperature adjusting mechanisms 20, 25 and 30 are different from the above-mentioned liquid type,
Of course, indirect temperature adjustment by a heater or a heat transfer medium may be used.

In the disk substrate molding die apparatus 1 thus constructed, the movable die 4 moves closer to the fixed die 3 by the operation of the driving mechanism (not shown), so that the die is clamped. Thus, the cavity 6 whose periphery is closed is formed. Then, the cavity 6 is injected and filled with the molten synthetic resin material 7 from the nozzle 10 of the sprue bush 11 in this mold clamping state. The disk substrate molding die device 1 includes a first, second, and third temperature adjusting mechanism 2
When the synthetic resin material 7 is cooled by 0, 25, and 30 into a semi-molten state, the first eject member 1
The punch 13 is caused to project from the center hole 5 in the direction of the fixed mold 3 to form the center hole 9 of the disk substrate 2 to be molded.

After that, the disk substrate molding die apparatus 1 has the first, second, and third temperature adjusting mechanisms 20, 25, 30.
To evenly cool and cure. Therefore, in the disk substrate 2 molded by this disk substrate molding die device 1, the contraction of the synthetic resin material 7 in the cavity 6 during cooling becomes uniform, and the main surface of the disk substrate 2 is molded flat. You can

As described above, the mold device 1 for molding the disk substrate
After the synthetic resin material 7 in the cavity 6 is cooled,
A drive mechanism (not shown) operates to move the movable mold 4 away from the fixed mold 3 to perform a mold opening operation. The disk substrate 2 molded in the cavity 6 is moved by the first ejecting member 15 operating in a state where the fixed mold 3 and the movable mold 4 are opened. 4 and is taken out by a disc substrate take-out mechanism (not shown).

According to the disk substrate molding die apparatus 1 thus constructed, the disk substrate 2 to be molded is particularly preferable.
Is cooled in the same manner as the fixed mold 3 and the movable mold 4 which are cooled by the first and second temperature adjusting mechanisms 25 and 30 by the third temperature adjusting mechanism 30 provided in the outer peripheral mold 5. Therefore, unlike the case of using the conventional mold apparatus for molding a disk substrate, a protrusion generated at the time of molding does not occur on the outer peripheral side of the disk substrate. Therefore, it is not necessary to cut off the outer peripheral side of the disk substrate molded as in the conventional case, and it is possible to mold many concave and convex patterns accordingly.
It is possible to increase the capacity of the magnetic disk.

The mold apparatus 1 for molding a disk substrate described in detail above is a mold apparatus for manufacturing a disk substrate 2 which constitutes a magnetic disk built in a hard disk device used in a computer system. However, it is needless to say that the disk-shaped recording medium substrate molding die apparatus according to the present invention may be applied to a disk substrate molding die apparatus for molding a disk substrate used for an optical disk, a magneto-optical disk or the like. Is.

[0034]

According to the mold apparatus for molding a disk-shaped recording medium substrate according to the present invention, the fixed mold, the movable mold and the outer peripheral mold are provided with the first, second and third temperature adjusting mechanisms, respectively. Since it is provided, the resin material in the cavity is uniformly cooled and contracted. Therefore, unlike the prior art, no protrusion, which is a molding strain, is formed on the outer peripheral side of the disc-shaped recording medium, and an uneven pattern can be formed on the outer peripheral side as well, thereby increasing the capacity of the disc-shaped recording medium. Can be planned.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a disk substrate molding die device to which the present invention is applied.

FIG. 2 is a sectional view of essential parts showing first, second and third temperature adjusting mechanisms of the same disk substrate molding die device.

FIG. 3 is a plan view of a main part of a fixed mold provided with a first temperature adjusting mechanism.

FIG. 4 is a plan view of a main part of a movable mold and an outer peripheral mold provided with second and third temperature adjusting mechanisms.

FIG. 5 is a cross-sectional view of essential parts of a conventional die device for molding a disk substrate.

FIG. 6 is a sectional view of an essential part of a disk substrate molded by the same disk substrate molding die device.

FIG. 7 is a side view of a disc substrate molded by the same disc substrate molding die device.

[Explanation of symbols]

1 mold apparatus for molding a disk substrate, 2 disk substrates,
3 fixed metal mold, 4 movable metal mold, 5 outer peripheral metal mold, 6 cavity, 7 synthetic resin material, 8 stamper, 10 nozzles, 11 sprue bush, 12 second eject member, 13 punch, 14 resin reservoir, 15 1st Eject member, 16 set screw, 20 first temperature adjusting mechanism, 25 second temperature adjusting mechanism, 30 third temperature adjusting mechanism

Claims (1)

[Claims] 1. A fixed mold that forms one main surface of a disk-shaped recording medium substrate, and another main surface of the disk-shaped recording medium substrate that is arranged so that it can be brought into contact with and separated from the fixed mold. And a peripheral die that forms an outer peripheral surface of the disk-shaped recording medium substrate and defines a cavity filled with a resin material by the fixed die and the movable die, and the fixed die. A first temperature adjusting means for adjusting the temperature of the mold, a second temperature adjusting means for adjusting the temperature of the movable mold, and a third temperature adjusting means for adjusting the temperature of the outer peripheral mold, The first temperature adjusting means, the second temperature adjusting means and the third
The temperature adjusting means of (1) independently adjusts the temperatures of the fixed mold, the movable mold, and the outer peripheral mold, and a mold device for molding a disk-shaped recording medium substrate.