JPH10309722A - Resin mold for optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the occurrence of pits and drawing and warpage of grooves in a resin molding plate with respect to the mold of a resin molding plate of an optical disk used as an optical information recording medium. SOLUTION: The mold is of a structure having a stamper 1 and an outer circumferential stamper holder 4 secured to a stationary side specular surface 2 and removing a molding plate from the stationary side of a molding machine, and an outer circumferential stamper holder 4 has a moving function of projecting out of the stationary side of the molding machine simultaneous with mold opening operation during the mold opening period after the completion of molding, and by the function, the molding plate is such that its inner circumference and outer circumference are released at the same time in accordance with mold opening. As such, the occurrence of pits of the resin molding plate and distortion, drawing, and warpage grooves can be prevented, thus obtaining an optical information recording medium with high reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is mainly used when injection-molding an optical disk substrate such as a phase-change optical disk or a magneto-optical disk (hereinafter, represented by an optical disk) used as an optical information recording medium. The present invention relates to a resin mold for an optical disk.

[0002]

2. Description of the Related Art In a conventional resin molding die for an optical disk, a stamper on which an information signal is formed is mounted on a movable side of a disk molding die set in an injection molding machine, and a fixed mirror surface of a die is formed. ) And the cavity between the outer stamper holder that forms the outer diameter of the optical disk substrate, the mold structure for filling the molten resin and the mounting surface of the stamper are mounted on the fixed side, and the movable mirror surface and the outer diameter of the optical disk substrate are adjusted. As described above, there is a mold structure for filling the cavity between the formed outer peripheral stamper holder and the molten resin. The outer peripheral stamper retainer of the molding die is mounted in a state of being fixed to the stamper mounting side.

Hereinafter, a conventional example of a fixed stamper will be described with reference to the drawings. FIG. 5 is a view showing an outer peripheral stamper holding portion of a fixed-side stamper mounting method, which is a typical conventional resin molding die for an optical disk in which the portion A in FIG. 1 of the present invention is enlarged.

Reference numeral 4a denotes an outer peripheral stamper retainer, 2a denotes a fixed-side mirror surface, 13a denotes a movable-side mirror surface, 7a denotes an outer peripheral stamper retainer tightening bolt, 1a denotes a stamper, 19a denotes a cavity, and the outer peripheral stamper retainer 4a is an outer peripheral surface to the fixed-side mirror surface 2a. It is tightened with the stamper holding tightening bolt 7a,
Fixed.

The D portion of the outer stamper retainer 7a is formed in a tapered shape or a tapered shape so as not to be undercut due to the draft angle of the molding.

FIG. 6 shows the mold release state of the optical disk molding substrate when the molten resin is filled by actual injection molding in the mold structure of FIG.
1a is a sprue, 3a is an inner peripheral stamper holder, 11a is a fixed side bush, 12a is a sprue bush, 22a is a sprue runner, 16a is a gate cut punch, 15a
Is the eject ring, 17a is the eject pin, 14a
Indicates a movable bush. In the stamper 1a, the inner peripheral stamper retainer 3a is inserted into the center hole, and attached to the fixed-side mirror surface 2a. The gate cut punch 16a operates during the molding and cooling of the molten resin to form a center hole of the optical disk molding substrate. The eject ring 15a has a function of ejecting the molded substrate, and the eject pin 17a has a function of ejecting the sprue 21a when taking out the sprue 21a.

The operation of the conventional example will be described below with reference to FIGS. With the high-pressure mold clamped, the molten resin flows from the injection molding machine nozzle at high speed and high pressure through the sprue-runner 22a, and the stamper 1a attached to the fixed mirror 2a and the movable mirror 13a.
Is filled in the cavity 19a between the outer peripheral stamper retainer 4a and the outer diameter stamper holder 4a. The gate cut punch 16a operates during cooling of the molding to form a center hole of the molding substrate 20a. When the cooling of the molding is completed, the mold is opened and the molded substrate 2 is opened.
0a is moved to the movable side together with the sprue 21a, and is delivered by a take-out robot or the like. The sprue when the mold is opened
The principle when the mold 21a and the molded substrate 20a are released from the stamper 1a is that the sprue 21a has an undercut in the sprue-cold slag portion.
The molded substrate 1a is separated from the fixed bush 11a located at the center and the inner peripheral stamper holder 3a, and between the movable bush 14a and the movable mirror surface 13a before and after opening the mold. Force due to timely blow of mold air and sprue 21a of center hole of molded substrate
The mold is released by the biting resistance of the mold, and after the mold is opened,
Both the molded substrate 20a and the sprue-21a move to the movable side.

[0008]

However, in the above-mentioned conventional resin molding die for an optical disk, the molding substrate 20a is gradually released from the stamper 1a from the center to the outer periphery. From the middle circumference to the outer circumference zone of the stamper 20a, the release does not proceed uniformly, and the pits or grooves of the information recording signal recorded on the stamper 1a are distorted, sagged or caught, and the molded substrate 20a There was a problem of warping. If the optical disk substrate has an abnormality at the time of the release, the mechanical characteristics (warp, acceleration, etc.) of the disk become large, and there has been a problem that the recording and reproduction of signals are not performed correctly.

The present invention solves the above-mentioned conventional problems. When the mold is opened after completion of molding, the outer peripheral stamper retainer is fixed to the molding machine when the mold is opened so that the mold is released from the outer periphery simultaneously with the inner periphery. An object of the present invention is to provide a resin molding die for an optical disk that protrudes from the side to realize high-quality duplication of an optical disk.

[0010]

According to the present invention, there is provided a resin molding die for an optical disk according to the present invention, wherein a stamper mounting surface is fixed to a molding machine fixed side, and a mold mirror surface for forming an opposite signal surface is movable with the molding machine movable. In the mold of the configuration provided on the side, the outer peripheral stamper press forming the outer peripheral end face is provided on the molding machine fixed side, and the molding substrate of the molding machine is taken out from the molding machine movable side,
The outer stamper retainer has a function of moving the molded substrate from the fixed side of the molding machine simultaneously with the opening of the mold when the mold is opened when the molding is completed.

According to the present invention, the mold substrate is released from the stamper only in parallel with the inner periphery and the outer periphery at the same time. Distortion of pits and grooves, sagging, warpage of the molded substrate, and the like that occur at the time are eliminated, and an optical disk substrate having excellent signal recording and reproducing characteristics can be obtained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, a stamper mounting surface for forming a signal of a resin molded substrate for an optical disk is formed on a molding machine fixed side, and a mirror surface of a mold for forming an opposite signal surface is formed. In the mold having a configuration provided on the movable side of the molding machine, an outer peripheral stamper press forming the outer peripheral end face is provided on the fixed side of the molding machine, and the molding substrate of the molding machine is taken out from the movable side of the molding machine. The stamper retainer is a resin molding die for an optical disc having a moving function that protrudes from the fixed side of the molding machine simultaneously with the mold opening when the mold is opened upon completion of molding. It is characterized in that the mold release is performed simultaneously on the inner circumference and the outer circumference, and has an effect that a stable release can be realized.

According to a second aspect of the present invention, the outer peripheral stamper retainer has a structure in which a taper or a projection is provided in a direction in which the molded substrate is protruded when the mold is opened when molding is completed, or when the stamper protrudes from the fixed side of the molding machine. The resin molding die for an optical disk according to the above, wherein the effect of claim 1 is further improved.

According to a third aspect of the present invention, a stamper mounting side for mounting a stamper for forming a signal of the resin molded substrate for an optical disk and a mirror mounting side for mounting a mold mirror surface for forming an opposite signal surface are provided. In the mold, the outer peripheral stamper retainer forming the outer peripheral end face is provided on the stamper mounting side, and when removing the molded substrate of the molding machine, the outer peripheral stamper retainer is mounted at the same time as the mold is opened when the mold is opened when molding is completed. A resin molding die for an optical disc having a movement function of protruding from the side, characterized in that the mold is released from the inner and outer periphery simultaneously by the movement function of the outer periphery stamper press when the mold is opened; It has the function of realizing release.

According to a fourth aspect of the present invention, there is provided a structure in which the outer peripheral stamper retainer is provided with a taper or a projection in a direction in which the molded substrate is protruded when the mold is opened when molding is completed, or when the stamper protrudes from the stamper mounting side. The resin molding die for an optical disc according to the above, wherein the effect of claim 3 is further improved.

An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a cross-sectional view of a resin molding die for an optical disk according to the present invention. In FIG. 1, a stamper 1 on which information signals of pits and grooves are formed is fixed to an inner peripheral stamper holder 3 on a fixed mirror surface 2 located on the molding machine fixed side. Installed by. Further, the fixed-side mirror surface 2
In some cases, vacuum suction may be added. On the outer periphery of the stamper 1, an outer stamper holder 4 for determining the outer diameter of the molded substrate is mounted on the fixed-side mirror surface 2 via a ball bearing 5,
The outer stamper retainer 4 is fixed to the movable rod 6 with a fastening bolt 7. The outer peripheral stamper retainer 4 and the movable rod 6 are configured to be pushed up by a compression spring 9 embedded in a fixed-side mold plate 8. This compression spring 9
Are provided at 4 to 8 places on the circumference of the outer stamper retainer 4. A cooling water channel 1 for mold temperature control is provided on the fixed-side mirror surface 2.
The fixed side bush 11 and the sprue bush 12 are provided at the center via the inner peripheral stamper retainer 3. Movable mirror surface 13 located on the molding machine movable side
A cooling water passage 10b is formed in the center, and a movable side bush 14 and an eject ring 1 for projecting a molded substrate are formed in the center.
5. Gate cut punch 1 for punching the center hole of molded substrate
6. Further, a projecting pin 17 for projecting the sprue-runner is provided. With the resin molding die for an optical disk thus configured, polycarbonate (P
C), a molten material of a resin for an optical disk represented by acrylic (PMMA) is injected and filled from a molding nozzle 18, filled into the space of the cavity 19 through the sprue bush 12, and formed into fine grooves and pits of the stamper 1. This is to obtain a transferred molded substrate.

Referring to FIG. 2, the function of moving the outer stamper retainer 4 of the present invention will be described. FIG. 2 is a detailed view of part A of FIG. 1 (a).
Shows a state when the mold is opened, and (b) shows a state when the mold is closed. When the mold is open, the outer peripheral stamper retainer 4 is pushed out by the force of the compression spring 9 via the movable rod 6, and a gap D1 is generated between the stamper 1 and the outer periphery. This operation is extruded simultaneously with the mold opening.
When the mold is closed, the outer peripheral stamper presser 4 is pushed by the movable mirror surface 13 as shown in FIG. 2B, and the gap between the stamper 1 and the stamper 1 becomes D2. The movable amount of the outer stamper holder 4 is regulated by the dimension D3.

Referring to FIG. 3, a description will be given of a release state of the molded substrate after the actual injection molding. With the high-pressure mold clamped in FIG. 1, the molten resin flows from the injection molding machine nozzle 18 at high speed and high pressure through the sprue bush 12, and forms an outer diameter with the stamper 1 attached to the fixed mirror 8 and the movable mirror 13. The cavity 19 between the stamper holder 4 is filled, and the gate cut punch 16 moves forward during the cooling of the molding to form the center hole of the molding substrate. When the molding has finished cooling,
As shown in FIG. 3, when the mold is opened and the mold substrate 20 is released, the inner portion and the outer periphery are simultaneously released by the pushing function of the outer stamper retainer 4 at the center portion and the sprue 21 at the outer portion.

The center of the molded substrate 20 is the stamper 1
The principle at the time of release from the mold is the same as the conventional example,
Is provided with an undercut so that the sprue 21 is pulled out on the movable side when the mold is opened. This sprue
The mold 21 and the center hole of the molded substrate 20 are released from the stamper 1 as the sprue 21 is pulled out in order to open the mold in a partially cut-off state. Further, before and after the mold is opened, a function is provided in which mold release air is blown out from the center between the fixed side bush 11 and the inner peripheral stamper holder 3 and between the movable side bush 14 and the movable side mirror surface 13 with good timing. By doing so, the releasability is further improved.

FIG. 4 is an enlarged sectional view of a portion B in FIG. 2B. In order to improve the effect of pushing up the molded substrate of the outer peripheral stamper retainer 4, if the C portion of the outer peripheral stamper retainer 4 is formed in a projecting shape, even if the outer diameter of the molded substrate becomes smaller due to the molding shrinkage of the molded substrate. The outer periphery can be uniformly released without being affected by the influence.

As described above, the present invention provides a resin molding die for an optical disk in which the mold substrate is released from the mold when the mold is opened.

In the present invention, the amount of movement D3 is not particularly limited. However, if the amount of movement D3 is too large, the molding gas that adheres between the stamper 1 and the outer stamper holder 4 stains the stamper 1, so that the amount of movement is 3 mm. The following is desirable. Also,
Although the outer peripheral stamper holder 4 is pushed out by using the compression spring 9, a method in which air is moved in and out of a piston cylinder having a seal instead of the movable rod 6 may be used. In the case of the method of moving using the air pressure, since the air pressure is evenly applied to the piston cylinders for pushing and pressing the outer peripheral stamper provided at several places, the movement of the outer peripheral stamper retainer is better than the method using the compression spring. Air pressure fluctuations need to be managed.

In the above embodiment, the mirror surface of the mold is provided on the movable side.
Although the description has been made using a molding die having a structure in which a stamper and a stamper retainer are provided on the fixed side, reversing the relationship between the movable side and the fixed side is relatively easy to achieve and has the same effect. It is within the scope of the invention.

In addition, there is a resin molding die for an optical disk having a structure in which an outer peripheral stamper retainer is movably mounted on the fixed side stamper. However, this is for the purpose of effecting mold release of the molded substrate. In addition, the mold release effect is small, and the mold structure is different from the present invention.

[0025]

As described above, according to the present invention, the stamper mounting surface and the outer peripheral stamper holder are provided on the fixed side of the molding machine, and the molded substrate is taken out from the movable side of the molding machine. When the mold is opened, when the mold is opened, the mold release of the molded substrate when the mold is opened is provided by providing a resin molding die for optical discs that has a movement function that protrudes from the fixed side of the molding machine at the same time as the mold is opened. The outer circumference is performed simultaneously. Said,
By simultaneously releasing the mold from the inner circumference and the outer circumference, the pits and grooves of the information recording signal of the stamper, which had been generated by the conventional method of releasing from the inner circumference toward the outer circumference, are dripped or caught. And the problem that the molded substrate warps can be solved. By solving the above problem, the mechanical characteristics (warpage, acceleration, etc.) of the optical disk substrate are improved, and the recording and reproducing characteristics of signals when the optical disk is formed are improved, so that the reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a resin molding die for an optical disk according to the present invention.

FIG. 2 is a partial cross-sectional view showing the operation of pressing the outer peripheral stamper when the mold is opened and when the mold is closed according to the present invention.

FIG. 3 is a partial cross-sectional view showing a release state of a molded substrate according to an embodiment of the present invention.

FIG. 4 is a partial cross-sectional view illustrating a shape of an outer stamper retainer according to a second embodiment of the present invention.

FIG. 5 is a partial cross-sectional view showing a conventional outer stamper retainer when the mold is closed.

FIG. 6 is a partial cross-sectional view showing a release state of a conventional molded substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a Stamper 2, 2a Fixed-side mirror surface 3, 3a Inner-peripheral stamper retainer 4, 4a Outer-peripheral stamper retainer 5 Ball bearing 6 Movable rod 9 Compression spring 11, 11a Fixed-side bush 12, 12a Sprue-bushing 13, 13a Movable-side mirror surface 14, 14a Movable bush 15, 15a Eject ring 16, 16a Gate cutting punch 17, 17a Eject pin

Claims (4)

[Claims] 1. A mold having a structure in which a stamper mounting surface for forming a signal of a resin molded substrate for an optical disk is provided on a molding machine fixed side, and a mold mirror surface for forming an anti-signal surface is provided on a molding machine movable side. The outer peripheral stamper retainer to be formed is provided on the molding machine fixed side, and the molding substrate of the molding machine is a mold having a structure taken out from the movable side of the molding machine. At the same time, a resin molding die for optical discs that has a movement function that protrudes from the molding machine fixed side. 2. The resin molding metal for an optical disk according to claim 1, wherein the outer peripheral stamper retainer has a structure in which a taper or a projection is provided in a direction in which the molded substrate is projected when the mold is opened when the molding is completed, and when it is projected from the molding machine fixed side. Type. 3. A mold having a stamper mounting side for mounting a stamper for forming a signal of a resin molded substrate for an optical disc and a mirror mounting side for mounting a mold mirror surface for forming an opposite signal surface. The outer peripheral stamper retainer to be formed has a stamper mounting side, and when removing the molded substrate of the molding machine, the outer peripheral stamper retainer is used when the mold is opened when the molding is completed.
A resin mold for optical discs that has a movement function that protrudes from the stamper mounting side at the same time as the mold is opened. 4. A structure in which the outer peripheral stamper retainer has a structure in which a taper or a projection is provided in a direction in which the molded substrate is protruded when the mold is opened when the mold is completed, and when it is protruded from the stamper mounting side.
The resin molding die for an optical disc according to the above.