JPH08300421A - Mold device for optical disk substrate - Google Patents

Abstract

PURPOSE: To dispense with the installation precision of die exchange for disk substrates having different thickness by including the first and second dies which move relatively between a mold opening position and a die closing position, installing stamper in the first die, and injecting molten resin in a molding space formed between the first and second dies at die closing position. CONSTITUTION: A die device for an optical disk substrate has a fixed side mold part 2 (second mold) and a movable side die device 3 (first mold). The movable side die 3 has a movable side mirror surface board 13 having one surface of an optical disk substrate to be molded which is installed on a movable side die plate, or a surface for supporting a stamper 16, and the side wall 6a of the peripheral step part of a fixed side mirror surface board 6 which forms the other surface of the optical disk substrate to be molded and the inside surface 17a of a sliding outside surface stipulating ring 17 stipulate the outside surface of a molding space 10. Molded resin to be injected from a nozzle is lead into the space 10 through a sprue bush 11.

Description

Detailed Description of the Invention

[0001]

[0001]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk substrate molding die apparatus capable of molding substrates having different thicknesses.

[0003]

[0002]

[0004]

2. Description of the Related Art Most transparent substrates for information recording disks such as optical disks are made of PC (polycarbonate) or PMMA.
(Polymethylmethacrylate) or the like is used as a material and is formed by an injection molding device. As shown in FIG. 3, an injection molding apparatus for molding this optical disk substrate has a fixed mold section 2 having a molding space (not shown) provided on a fixed platen 1, and a molding space for this fixed mold section 2. And a movable platen 4 having a molding stamper (not shown) and a movable mold part 3 movably provided in a direction perpendicular to the molding surface. Further, a hydraulic cylinder as a mold clamping means (not shown) for clamping the fixed mold part 2 and the movable mold part 3 with each other while moving the movable platen 4 is provided, and after the mold is clamped, the injection device 5 is used. The member to be molded is injected into the molding space formed between the fixed mold unit 2 and the movable mold unit 3 to mold the disk substrate.

FIG. 4 is a detailed cross-sectional view of the inside of the molding die of the conventional injection molding apparatus, showing the center half of the molding die. As shown in FIG. 4, the fixed-side mold section 2 is composed of a fixed-side mirror surface plate 6, a fixed-side bush 7, a fixed-side guide ring 8 and the like, and is fixed on the fixed-side mold plate 9 with several bolts (not shown). Has been done. The disk-shaped fixed-side mirror surface disk 6 that has been mirror-finished forms one surface of a molding space 10 for molding a disk substrate.

The hollow cylindrical fixed-side bush 7 is inserted from the surface of the fixed-side mold plate 9 into the central portion of the fixed-side mirror surface plate 6, and is unnecessary in the outer peripheral portion in cooperation with a cut punch 20 described later. It has a blade portion for cutting the molding material that becomes.
The tip of the injection device 5 is joined to a locate ring 12 provided in the center of the fixed-side template 9, and a material to be molded in a molten state heated by the injection device 5 is injected into the hollow structure. It is injected into the molding space 10 through the spool bush 11 having the above shape.

[0007]

On the other hand, the movable mold part 3 is a movable mirror surface plate 1
3, movable side guide ring 14 and outer peripheral surface defining ring 17
It is fixed on the movable side mold plate 15 with several bolts (not shown). The disk-shaped movable side mirror surface disk 13 subjected to mirror surface processing is provided at a position corresponding to the fixed side mirror surface disk 6 and forms the other surface of the molding space 10. Further, a disk-shaped stamper 16 having a predetermined information pattern engraved thereon is loaded on the movable side mirror surface disk 13, and the inner peripheral edge portion of this stamper 16 is an inner peripheral portion having a hollow cylindrical outer peripheral edge portion and having a hook-shaped portion. It is fixed by a peripheral stamper retainer 18, and the outer peripheral edge of the stamper 16 is fixed by an outer peripheral surface defining ring 17. A cam 19 is connected to the other end of the inner peripheral stamper retainer 18, and the inner peripheral stamper retainer 18 is moved in conjunction with the cam 19 so that the stamper 16 can be attached and detached. A cut punch 20 is provided at the center of the inner stamper retainer 18 and cooperates with the fixed bush 7 to cut unnecessary molding material.

In the above-mentioned molding die, when the movable side mold part 3 is brought close to the surface of the fixed side mold part 2 in the vertical direction in order to close the molding die, the fixed side guide ring 8 and the movable side guide ring are formed. 14 is fitted and abutted to be positioned, and the mold is clamped. When the molten resin is poured into the molding space 10 in this closed mold position and cooled, a disk substrate on which the information pattern engraved on the surface of the stamper 16 is transferred is molded. After that, the movable side mold part 3 is separated from the fixed side mold part 2, the molding die is opened, and the disk substrate is taken out.

[0009]

[0004]

[0010]

By the way, an optical disc having a diameter of 12 cm, which is the same as a CD (compacted disc), and a thickness of 0.6 mm, which is 1.2 mm of a CD, is used. A DVD (Digital Video Disc) has recently been proposed.

Therefore, since the diameter is the same, CD and DV
It is conceivable that the molding die of the disk substrate of D is shared, but it is necessary to replace a part of the die because the thickness is different. However, in the molding die of FIG. 4, two sets of fixed-side mirror surface discs and fixed-side bushes having different sizes are prepared and replaced, and they are fixed accurately by a plurality of fixing bolts (not shown). Therefore, it takes a lot of time for the replacement work, and after the replacement work, it is necessary to finely adjust the mounting accuracy, and it is common to perform trial molding several times.

As described above, in the conventional mold, the replacement work takes a lot of time, and a separate fixed-side mirror surface plate and fixed-side bush are required for each thickness of the disk substrate, which results in mold cost. There was a problem of rising prices.

The present invention has been made in view of the above-mentioned problems, and does not require mounting accuracy for die replacement for optical disc substrates such as DVDs and CDs having different disc substrate thicknesses. It is an object of the present invention to provide an inexpensive and sharable mold device for an optical disk substrate.

[0014]

[0005]

[0015]

SUMMARY OF THE INVENTION The present invention includes first and second molds movable relative to one another between an open position and a closed mold position, wherein a stamper is attached to the first mold. An optical disk substrate for molding an optical disk substrate on which information of the stamper is transferred by injecting a molten resin into a molding space formed between the first and second molds at a closed position. In a molding die device, the first and second dies are attached to the second die so as to be movable in a moving direction, and define an outer peripheral surface of the molding space at the closed die position. An outer peripheral surface defining ring, a means for urging the outer peripheral surface defining ring to project toward the first mold side, a means for restricting a movement amount of the outer peripheral surface defining ring, the first or second It is attached to the outer circumference of the facing surface of the mold of the Characterized in that a removable spacer member defining a gap between the molding space.

[0016]

[0006]

[0017]

According to the molding die apparatus for an optical disk substrate of the present invention, the outer peripheral surface defining ring is movably provided on the second die facing the first die to which the stamper is attached, and the first or second die. Since the spacer member for defining the size of the gap of the molding space is detachably provided on the outer periphery of the facing surface of the mold, the outer peripheral surface defining ring provided on the second mold is used for the first mold during the mold clamping operation. The outer peripheral edge portion of the stamper attached to the mold is sandwiched, and the spacer member comes into contact with the facing surface of the mold to stop the mold clamping movement.

[0018]

[0007]

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical disk substrate molding die apparatus as an embodiment of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, an optical disk substrate molding die apparatus according to the present invention comprises a stationary die section 2 (second die),
The fixed-side mold part 2 and the movable-side mold part 3 (first mold) provided so that the molding surfaces face each other and are movable in a direction perpendicular to the molding surface. are doing.
Although not shown, there is provided mold clamping means including a hydraulic cylinder or the like for moving the movable mold part 3 and clamping the fixed mold part 2 and the movable mold part 3 together. The fixed-side mold section 2 includes a fixed-side mold plate 9, a fixed-side mirror plate 6 that is attached to the fixed-side mold plate 9 and forms one surface of an optical disk substrate to be molded, and the fixed-side mold plate. It is composed of a fixed side guide ring 8 and a guide post 26 for positioning the two mold parts when the mold is clamped. A hollow fixed-side bush 7 is inserted so as to penetrate the center of the fixed-side mirror surface plate 6, and a cylindrical spool bush 11 is provided in the fixed-side bush 7, and one end of the spool bush 11 is provided. A locating ring 12 that engages with the tip of the nozzle of the injection unit (not shown) is provided. The molten resin injected from the nozzle of the injection means is guided into the molding space 10 through the spool bush 11. An outer peripheral surface defining ring 17 that holds the outer peripheral edge portion of the stamper 16 at the time of mold clamping moves in a direction orthogonal to the molding surface of the fixed-side mirror surface disk 6 at a portion corresponding to the outer peripheral portion of the fixed-side mirror surface disk 6. It is freely engaged with the outer peripheral step portion of the fixed-side mirror surface plate 6. The inner peripheral surface 17 a of the outer peripheral surface defining ring 17 that slides on the side wall 6 a of the outer peripheral step portion of the fixed-side mirror surface plate 6 defines the outer peripheral surface of the molding space 10. The outer peripheral surface defining ring 17 is biased by a biasing means composed of a spring 21 so as to protrude from the molding surface of the fixed side mirror surface plate 6 toward the movable side mold part 3, and at the same time, the fixed side guide ring 8 is pressed. An annular first spacer member 22 detachably attached by a bottle 23 to the surface facing the movable mold part 3 and an outer peripheral step part of the outer peripheral surface defining ring 17 are engaged with each other, and their movement is restricted. . The first spacer member 22 defines the size of the gap in the molding space 10 by contacting the movable side guide ring 14 described later when the mold is clamped (closed mold position).

[0021]

On the other hand, the movable mold part 3 has a movable mold plate 15
A movable side mirror surface plate 13 having the other surface of the optical disk substrate to be molded attached to the movable side template 15, that is, a surface for supporting the stamper 16, and a mold clamp attached to the movable side template 15 The stationary side guide ring 8 is fitted to the movable side guide ring 14 for positioning. The movable guide ring 14 is provided with a recess into which the guide post 26 is fitted, and a bearing 27 on the inner surface of the recess that slides on the outer peripheral surface of the guide post 26. An inner peripheral stamper pressing ring 18 for pressing the inner peripheral edge of the stamper 16 and fixing it to the movable side mirror surface plate 13 is provided at a portion corresponding to the inner peripheral portion of the stamper 16. Further, a vacuum suction means (not shown) is provided on the surface of the movable side mirror surface plate 13 corresponding to the outer peripheral edge portion of the stamper 16, and the outer peripheral edge portion of the stamper 16 is fixed to the movable side mirror surface plate 13 by vacuum suction. ing. A cylindrical cut punch 20 is provided in the inner peripheral stamper pressing ring 18 so as to be movable in a direction perpendicular to the molding surface. The tip portion of the cut punch 20 cooperates with the end portion of the fixed-side bush to punch the center hole of the optical disc substrate.
As shown, centering and positioning of the fixed side mold part 2 and the movable side mold part 3 at the time of mold clamping are performed by engaging the tape surface 8a of the fixed side guide ring and the taper surface 14a of the movable side guide ring. This is done by using the guide post 26 and the bearing 27 together.

An annular second spacer member 24, which is movable and comes into contact with the outer peripheral surface defining ring at the time of mold clamping, is detachably attached to the outer peripheral step portion of the air mirror surface plate 13.

[0023]

Next, the operation of the optical disk substrate molding die apparatus having the above-described structure will be described.

From the open mold position where the fixed mold part 2 and the movable mold part 3 are separated from each other, the movable mold part 3 is moved to the closed mold position with respect to the fixed mold part 2. Then, the outer peripheral surface defining ring 17 comes into contact with the outer peripheral edge portion of the stamper 16 and with the movement of the movable side mold portion 3, the outer peripheral surface defining ring 17 is recessed by the biasing force of the spring 21. Then, the first spacer member 22 comes into contact with the movable side guide ring 14, the movement of the movable side mold part 3 is stopped, the mold is closed, and the mold is clamped, and the fixed side mirror surface plate 6 and the movable side mirror surface plate. A molding space 10 is formed between the molding space 10 and the molding space 10. At this time, the outer peripheral surface defining ring 17 is brought into close contact with the second spacer member 24, so that the outer peripheral surface defining ring 1
A gap is formed between 7 and the outer peripheral edge of the stamper 16 to the extent that no burr or the like appears. In this gap, the molten resin is molded into the space 1
It plays a role of ventilation when it is injected into 0.

By replacing the first spacer member 22 with a thick one as shown in FIG. 2B, the size of the gap in the molding space 10, that is, the thickness of the optical disk substrate to be molded can be changed. At this time, since the outer peripheral surface defining ring 17 moves in a direction perpendicular to the molding surface according to the thickness of the first spacer member 22, the fixed side that slides even if the thickness of the first spacer member 22 is changed. Side wall 6a of the outer peripheral step of the mirror surface plate 6
There is no gap between the inner peripheral surface 17a of the outer peripheral surface defining ring 17 and the inner peripheral surface 17a of the outer peripheral surface defining ring 17, and thus no burr is formed on the molded optical disk substrate.

In the above-mentioned embodiment, the first spacer member also has the function of limiting the movement of the outer peripheral surface defining ring, but the present invention is not limited to this, and the stopper means separate from the first spacer member. May be provided to limit the movement of the outer peripheral surface defining ring. Further, centering and positioning of the fixed-side mold part 2 and the movable-side mold part 3 are mainly performed by fitting the fixed-side and movable-side guide rings, and are additionally performed by guide posts and bearings. . Further, an example is shown in which the stamper and the second spacer member are provided in the movable side mold part, and the outer peripheral surface defining ring and the first spacer part are provided in the fixed side mold part. It is needless to say that the movable part and the latter part may be provided on the movable side mold part, respectively.

[0027]

[0010]

[0028]

As described above, in the molding die apparatus for an optical disk substrate of the present invention, the outer peripheral surface defining ring is movably provided in the second die facing the first die to which the stamper is fixed. At the same time, a spacer member that defines the size of the gap of the molding space is detachably provided on the outer periphery of the facing surface of the first or second mold, so that the mold can be replaced for the molding of optical disk substrates having different thicknesses. The accuracy is not required, and the replacement work can be easily performed.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a molding die apparatus for an optical disk substrate of the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a schematic view of a conventional molding die apparatus for an optical disc substrate.

FIG. 4 is a partial cross-sectional view of a conventional molding die device for an optical disc substrate.

[Explanation of symbols]

 1 ... ・ Fixed plate 2 ・ ・ ・ ・ Fixed side mold part 3 ・ ・ ・ ・ Movable side mold part 4 ・ ・ ・ ・ Movable plate 5 ・ ・ ・ ・ Injection device 6 ・ ・ ・ ・ ・ ・ Fixed side mirror surface plate 7: Fixed side bush 8: Fixed side guide ring 9 ... Fixed side template 10 ... Molding space 11 ... Spool bush 12 ... Locate ring 13 ... Movable side Mirror surface plate 14 ... Movable side guide ring 15 ... Movable side template 16 ... Stamper 17 ... Outer peripheral surface defining ring 18 ... Inner peripheral stamper retainer ring 19 ... Cam 20 ... Cut Punch 21 ... Spring 22 ... First spacer member 23, 25 ... Bolt 24 ... Second spacer member 26 ... Guide post

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahide Itoigawa 2680 Nishi Hanawa, Tatomi-cho, Nakakoma-gun Yamanashi Pioneer Video Co., Ltd. Within the corporation

Claims (3)

[Claims] 1. A first mold including a first mold and a second mold which are relatively movable between an open position and a closed mold position, a stamper being attached to the first mold, and the first mold having the stamper attached to the first mold. 1st and 2nd
An optical disk substrate molding die apparatus configured to mold an optical disk substrate to which information of the stamper has been transferred by injecting a molten resin into a molding space formed between the dies. An outer peripheral surface defining ring which is attached to the second mold so as to be movable in a direction orthogonal to the molding surface of the second mold and defines an outer peripheral surface of the molding space at the closed mold position; Means for urging the surface defining ring to project toward the first mold side; means for restricting the amount of movement of the outer peripheral surface defining ring; and outer circumference of the facing surface of the first or second mold. Mounted on the
A molding die apparatus for an optical disk substrate, comprising: a detachable spacer member that defines a size of a gap of the molding space at the closed position. 2. The molding for an optical disk substrate according to claim 1, wherein the spacer member is attached to the outer periphery of the second mold and also serves as a means for regulating the movement amount of the outer peripheral surface defining ring. Mold equipment. 3. The molding die for an optical disk substrate according to claim 1, wherein the first die is a movable die, and the second die is a stationary die. apparatus.