JPH0857908A - Molding tool for optical disc base - Google Patents

Abstract

PURPOSE: To provide a molding tool for an optical disc base wherein facilitating attachment and detachment of an inner stamper presser component and simplification of a structure of a boring cutter for a disc central hole can be achieved. CONSTITUTION: A fitting recess part 46 in which an inner stamper presser component 50 is fitted, is formed on a fixing side cavity forming face 34 to which a stamper 43 is equipped, and besides an air passage 4 open to an inner surface of the fitting recess part 46 is provided. Thereby, the inner stamper presser component 50 is fixed by adsorbing by negative pressure air, and besides a female cutter is constructed of an inner hole of the inner stamper presser component 50.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an optical disk substrate molding die for molding an optical disk substrate made of synthetic resin on which information of the stamper is transferred by using a stamper on which predetermined information is engraved.

[0002]

BACKGROUND ART Optical discs have come to be used in a wide range of fields such as audio, video, and computers.
Generally, in the manufacturing thereof, a molding die composed of a fixed die and a movable die which are fitted with each other to form a molding cavity is used, and a predetermined cavity is formed on either one of the fixed die and the movable die. After setting a circular plate-shaped stamper on which information is engraved, a predetermined resin material is filled into the molding cavity to mold a base (replica) on which the stamper information is transferred. And, for the base molded in this way,
By subjecting the reflective film to vapor deposition or the like, the intended optical disk is formed.

By the way, in a molding die for forming an optical disk substrate, there is a conventional technique of Japanese Patent Publication No. 5-13537.
As disclosed in Japanese Patent Publication No. 5-82805 and Japanese Patent Publication No. 5-82805, an inner stamper pressing member is screwed to a central portion of a mold so that it can be attached and detached. The inner peripheral edge of the stamper arranged above is held.

However, the inner stamper pressing member needs to be removed and attached each time the stamper is replaced, and the inner stamper pressing member of the conventional structure, which is attached to the mold by screwing, is very troublesome to remove and attach. For this reason, there is a problem that the stamper replacement work is troublesome and time-consuming, and the molding cycle of the optical disk is adversely affected.

Further, in general, a male cutter member and a female cutter member for punching out a central hole of an optical disk substrate are assembled at opposite positions at substantially central portions of cavity forming surfaces of a fixed mold and a movable mold. However, due to misalignment of the fixed mold and the movable mold, there was a risk that the male cutter member and the female cutter member would interfere (caulge) when punching the central hole. Since it is necessary to replace the cutter member, which is extremely troublesome, the interference of the cutter member has been a serious problem.

Furthermore, the monomer gas easily enters the assembling site of the female cutter member in the central portion of the fixed mold during molding, and after continuous operation for a long time, this monomer gas solidifies and mixes into the optical disk substrate. Since this may cause defects, it is necessary to remove the female cutter on a regular basis and clean it.However, in the case of a molding die of the conventional structure, a fixed die is used to remove the female cutter member. There is also a problem that the cleaning work is troublesome and time-consuming, and the workability is extremely poor because it has to be removed and disassembled.

[0007]

The present invention has been made under the circumstances described above, and the problem to be solved is that an optical disk having a simple structure in which an inner stamper pressing member can be easily attached and detached. It is to provide a molding die for a substrate.

Further, according to the present invention, the damage of the cutter member due to the interference between the male cutter member and the female cutter member for punching out the central hole of the optical disc base can be advantageously prevented, and the removal of the female cutter member in the fixed mold can be performed. It is also an object to provide an optical disk substrate molding die that is easy and has excellent cleaning workability.

[0009]

In order to solve such a problem, a feature of the present invention resides in that a cavity forming surface is provided with respect to a fixed die that forms a forming cavity by being fitted with a movable die. An annular inner stamper pressing member is removably provided in the central part of the optical disk substrate molding die for holding the inner peripheral edge portion of the stamper on the cavity forming surface by the inner stamper pressing member. The mold is provided with a fitting recess into which the inner stamper pressing member is fitted, and an air passage opening to the inner surface of the fitting recess is provided, and the inner stamper pressing member is sucked and fixed to the cavity forming surface side by negative pressure air. On the other hand, the inner hole of the inner stamper pressing member is punched by the inner peripheral edge portion of the inner stamper pressing member facing the movable mold. Lies in the fact you have configured the female cutter of use.

In this optical disk substrate molding die, in order to hold the outer peripheral edge portion of the stamper on the cavity forming surface of the fixed mold, the outer peripheral edge portion of the stamper is directly sucked by negative pressure onto the cavity forming surface. It is desirable to provide a suction mechanism that holds the outer periphery of the stamper by bolting it to the fixed mold, and it is particularly preferable to provide a negative die for the fixed mold. An annular outer stamper pressing member that is adsorbed and fixed by compressed air and holds the outer peripheral edge portion of the stamper is adopted.

In the optical disk substrate molding die having the structure according to the present invention, preferably, the inner stamper pressing member is externally mounted on the sprue bush.

Further, in the optical disk substrate molding die having the structure according to the present invention, the inner stamper pressing member is disposed in a direction perpendicular to the movable mold with respect to the fitting recess of the fixed mold. It is also possible to assemble it by fitting so that it can be loosened.

The amount of backlash displacement of the inner stamper pressing member with respect to the fitting recess is appropriately determined according to the dimensional accuracy of the mold, the support accuracy of the mold by the mold clamping device, the clearance between the male and female cutters, and the like. But in general,
It is preferable to set a gap between the inner stamper pressing member, the inner and outer peripheral surfaces, and the inner surface of the fitting recess to allow a backlash displacement of 20 to 40 μm.

Further, as described above, in the optical disk substrate molding die having the structure according to the present invention, in which the inner stamper pressing member is fitted into the fitting concave portion so as to be loosely displaceable, the inner stamper pressing member is pressed. Although it is possible to position the stamper on the cavity forming surface by fitting the member into the center hole of the stamper,
Preferably, a positioning protrusion that is positioned outward of the inner stamper pressing member in the direction perpendicular to the axis, protrudes toward the cavity forming surface, and is fitted into the center hole of the stamper to position the stamper on the cavity forming surface. , Fixedly provided to the fixed mold.

In this case, the positioning projection may be any one as long as it can be fitted into the center hole of the stamper to position the stamper on the cavity forming surface, such as an annular projection continuous in the circumferential direction or one circular circumference. It is possible to configure it with a plurality of discontinuous projections, etc., which are positioned at, but, for example, the axial end of the positioning sleeve fixedly assembled to the fixed mold is projected onto the cavity forming surface. Thereby, it is advantageously formed.

It is also possible to form the fitting recess by the inner hole of the positioning sleeve, and fit and mount the inner stamper pressing member in the inner hole of the positioning sleeve so as to be loosely movable. Furthermore, in that case,
By integrally forming a stamper pressing portion that extends over the axial end portion of the positioning sleeve and extends on the surface of the stamper with respect to the inner stamper pressing member, the inner peripheral edge portion of the stamper is formed on the cavity forming surface by the stamper pressing portion. Can be advantageously held at

Further, the positioning projection for positioning the stamper on the cavity forming surface by being fitted into the center hole of the stamper has a curved shape in which the outer peripheral edge portion of the projecting tip portion is chamfered in an arc shape. It is preferable to use a tapered surface having a surface or a straight line.

[0018]

In the optical disk substrate molding die having the structure according to the present invention as described above, the inner stamper pressing member is mounted on the fixed mold by suction with negative pressure air, and therefore the conventional screw is used. It is possible to attach and detach the stamper extremely easily and quickly as compared with the case of the wearing structure, whereby the workability at the time of exchanging the stamper and the improvement of the molding cycle can be achieved.

Further, in the optical disk substrate molding die having the structure according to the present invention, since the female cutter is constituted by the inner peripheral side edge portion of the inner stamper pressing member, a special female cutter member is unnecessary. As a result, the number of parts can be reduced and the structure can be simplified.

Moreover, the inner stamper pressing member functioning as such a female cutter is attached to the fixed mold by suction with negative pressure air, and since it can be easily attached and detached, it is defective due to monomer gas or the like. The cleaning work for preventing the occurrence is extremely easy, the assembling part of the female cutter can be easily cleaned every time the stamper is replaced, and the quality improvement and stabilization of the molded product can be advantageously achieved.

Further, in the optical disk substrate molding die having the structure according to the present invention, the annular outer stamper pressing member for holding the outer peripheral edge portion of the stamper is sucked and fixed to the fixed mold by negative pressure air. In this case, the stamper can be attached and detached more easily, and the molding cycle can be further improved.

Furthermore, if the inner stamper pressing member is externally mounted on the sprue bush, the inner stamper pressing member can be positioned advantageously.

Further, in the optical disk substrate molding die having the structure according to the present invention, in which the inner stamper pressing member constituting the female cutter is fitted into the fitting concave portion of the fixed mold so as to be loosely movable, and assembled, Even if a misalignment occurs between the male and female cutters due to the relative displacement between the fixed mold and the movable mold, the female cutter (inner stamper pressing member) is displaced as the male cutter advances and the cores are aligned. Therefore, it is possible to prevent galling between the male cutter and the female cutter and prevent damage to the cutter member, thereby improving durability and stabilizing the punching work of the central hole of the disk base. Of.

If the gap for allowing the backlash displacement set between the inner stamper pressing member, the inner and outer peripheral surfaces and the inner surface of the fitting recess is 20 to 40 μm, a general CD is used.
Good for male and female cutters, while ensuring smooth backlash displacement of the female cutter (inner stamper pressing member) against misalignment at the time of mold alignment that occurs when molding optical disc substrates for (compact discs). It becomes possible to more stably obtain the centering effect.

Further, a positioning protrusion is provided outside the inner stamper pressing member assembled in the fitting recess of the fixed die so as to be loosely displaced, and positioned in the center hole of the stamper. In the optical disk substrate forming die having the structure according to the present invention, even when the inner stamper pressing member is displaced due to the centering of the male and female cutters, the positioning protrusion causes the stamper to move to a predetermined position on the cavity forming surface. Therefore, the stamper can be effectively prevented from being deformed or damaged without exerting an unreasonable force on the stamper.

Further, if the outer peripheral edge of the projecting tip of the positioning projection is formed into a curved surface shape or a tapered surface shape, it becomes easy to fit the stamper central hole into the positioning projection, and the workability of setting the stamper is improved. Can be improved.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to clarify the present invention more specifically, one embodiment of the present invention will be described with reference to the drawings.
The details will be described.

First, FIG. 1 shows a cross-sectional view of a main part of an optical disk substrate molding die as an embodiment of the present invention. Such a mold includes a movable mold 10 and a fixed mold 12, and although not shown, the movable mold 10 is attached to the movable plate of the mold clamping device, while the fixed mold 12 is attached to the mold clamping device. It is attached to and supported by the fixed plate of, and the movable platen is driven toward and away from the fixed plate.
The movable mold 10 and the fixed mold 12 can be opened and closed. Then, as shown, the movable mold 10
By mating the fixed mold 12 with the mold, a disk molding cavity 14 is formed between the mating surfaces.

More specifically, the movable mold 10 has a thick plate-shaped movable mirror block 16 fixedly attached to the side where the molding cavity 14 is formed, and the movable mirror block 16 can be moved by the mirror surface of the movable mirror block 16. Side cavity forming surface 18
Is configured. Further, a bush 22 is built in the central portion of the movable mirror block 16 so as to penetrate through the movable mirror block 16, and the molded product of the optical disk substrate is released from the center hole of the bush 22. The ejector sleeve 24 is inserted so as to be movable in the axial direction, and is ejected to the fixed mold 12 side by a drive mechanism (not shown).

A male cutter 26 is inserted through the center hole of the ejector sleeve 24 so as to be movable in the axial direction, and penetrates the center axis of the male cutter 26 in the axial direction so that the sprue portion is formed. Ejector pin 28 for releasing
However, it is assembled so as to be movable in the axial direction. The tip surface of the male cutter 26 is projected at a predetermined height from the movable side cavity forming surface 18 to the fixed mold 12 side at the retracted position, and an annular gate is provided between the male cutter 26 and the fixed mold 12 side. To form a part.

On the other hand, similarly to the movable mold 10, the fixed mold 12 also has a fixed mirror block 30 fixedly attached to the side where the molding cavity 14 is formed. Forming surface 34
Is configured.

A sprue bush 36 is arranged and fixed to the fixed mold 12 so as to penetrate through the central portion of the fixed mirror block 30, and a resin introduction hole penetrating the central axis of the sprue bush 36. Through 38, a resin material injected from a nozzle of an injection device (not shown) is guided to and filled in the molding cavity 14.

Further, as shown in FIG. 2, which is an enlarged view of the main part, a substantially thin cylindrical positioning sleeve is formed in the central portion through hole 40 of the fixed mirror block 30 in which the sprue bush 36 is inserted. 40 is inserted, and is fitted and fixed to the inner peripheral surface of the central portion through hole 40.
Also, one axial end of the positioning sleeve 40 is projected on the fixed side cavity forming surface 34 at a predetermined height, and the projecting portion forms an annular positioning projection 42.

Then, with respect to the positioning protrusion 42,
By fitting the center hole of the stamper 43 in which predetermined information is engraved, the stamper 43 is positioned and arranged on the fixed side cavity forming surface 34. The height of protrusion of the positioning protrusion 42 from the fixed side cavity forming surface 34 is determined by the stamper 4 to be mounted.
It is set to be substantially the same as the thickness of No. 3.

The outer peripheral edge portion of the positioning protrusion 42 is chamfered into a rounded surface shape so that it can function as a guide surface when the stamper 43 is fitted into the center hole. It should be noted that the chamfered portion is left on the base side of the positioning protrusion 42, and the stamper 43 is positioned by fitting the chamfered portion into the center hole of the stamper 43. ing.

On the other hand, the axial end surface of the sprue bush 36 on the fixed side cavity forming surface 34 side is positioned in the positioning sleeve 40 so that the central portion thereof is projected more axially than the outer peripheral portion. Thereby,
An annular inner fitting recess 46 that opens toward the movable mold 10 is formed between the surfaces of the central protrusion 44 and the positioning sleeve 40 that face each other in the direction perpendicular to the axis. In addition, the sprue bush 36 is provided on the bottom surface of the inner peripheral side fitting concave portion 46.
An air passage 48 is provided so as to penetrate therethrough. A negative pressure source is connected to the inner peripheral fitting recess 46 by operating a switching valve (not shown) through the air passage 48. It has become.

Further, the inner stamper pressing member 50 having a substantially annular shape as a whole is fitted into the inner peripheral fitting recess 46, and the suction force of the negative pressure air exerted through the air passage 48 causes the inner peripheral portion to move. It is adapted to be sucked and fixed in the side fitting recess 46. An annular recessed groove 52 is provided on the axially inner end surface of the inner stamper pressing member 50, and the recessed groove 52 allows a space between the inner stamper pressing member 50 and the inner peripheral side fitting recess 46. Air passage 4
An annular air reservoir communicated with 8 is formed.

In addition, the axially outer end surface of the inner stamper pressing member 50 slightly axially outwardly protrudes from the outer peripheral edge portion, passes over the positioning projection 42 formed by the positioning sleeve 40, and outwardly in the direction perpendicular to the axis. An annular pressing protrusion 54 extending to the inside is integrally formed. And
The pressing projection 54 is superposed on the surface of the inner peripheral edge portion of the stamper 43 disposed on the fixed side cavity forming surface 34, so that the inner peripheral portion of the stamper 43 is placed on the fixed side cavity forming surface 34. It is designed to be held.

Furthermore, such an inner stamper pressing member 5
The inner diameter dimension of 0 is slightly larger than the outer diameter dimension of the male cutter 26 incorporated in the movable mold 10. And
Since the axially outer edge portion of the inner hole 66 of the inner stamper pressing member 50 is located so as to project from the axial end surface of the sprue bush 36 in the axial direction (to the movable mold 10 side) by a predetermined height, The inner stamper pressing member 50 constitutes a female cutter.

Further, here, the inner peripheral side fitting concave portion 46
The outer diameter of the central protrusion 44 of the sprue bush 36 forming the inner peripheral wall surface of the inner peripheral wall is smaller than the inner diameter of the inner stamper pressing member 50 by a predetermined dimension, and the outer side of the inner peripheral fitting recess 46 is The inner diameter of the positioning sleeve 40 forming the peripheral wall surface is larger than the outer diameter of the inner stamper pressing member 50 by a predetermined dimension.
In each of the parts (A) and (B), there is a slight gap between members. As a result, the inner stamper pressing member 50 can allow a predetermined amount of backlash displacement in the direction perpendicular to the axis while being fitted and assembled in the inner peripheral fitting recess 46. Since this backlash displacement is generated in a direction orthogonal to the direction in which the suction force of the negative pressure air acts, it can be generated smoothly even when the inner stamper pressing member 50 is suction-held.

Furthermore, such an inner stamper pressing member 5
The inner and outer diameters of 0, the outer diameter of the central protrusion 44 of the sprue bush 36 and the inner diameter of the positioning sleeve 40, which form the inner and outer wall surfaces of the inner fitting recess 46, and the inner diameter of the positioning sleeve 40 are different from each other. 10 is enough to absorb the misalignment between the male cutter 26 and the inner stamper pressing member 50 due to the positional deviation between the stationary die 10 and the fixed mold 12, and if it is too large, the inner stamper pressing member 50 is displaced. Since this may interfere with the positioning operation with the male cutter 26, it is desirable to set the thickness to 20 to 40 μm in a general CD molding die. The allowable backlash displacement amount of the inner stamper pressing member 50 is determined by the size of the smaller member gap of (A) and (B).
If the gap between the other members is too large, there is a problem such as penetration of the resin material. Therefore, it is desirable to set the sizes of the gaps between the members (A) and (B) to be substantially the same.

On the other hand, in the fixed mold 12, the outer peripheral portion of the fixed mirror block 30 is also formed with a ring-shaped outer peripheral fitting recess 56 that opens toward the movable mold 10 side, and this outer periphery is also formed. An air passage 58, which is opened and communicates with the bottom of the side fitting recess 56, is provided through the fixed mirror block 30, and is operated by a switching valve (not shown).
A negative pressure source is connected to the outer peripheral fitting recess 56.

Further, the outer stamper pressing member 60 having a substantially large-diameter annular shape is fitted into the outer peripheral fitting recess 56, and the outer peripheral fitting is performed by the suction force of the negative pressure air exerted through the air passage 58. It is adapted to be sucked and fixed in the recess 56. As with the inner stamper pressing member 50, an annular recessed groove 62 that forms an air reservoir is also provided on the axially inner end surface of the outer stamper pressing member 60.

A pressing projection 64 extending inward toward the fixed cavity forming surface 34 of the fixed mirror block 30 is integrally provided on the inner peripheral portion of the outer peripheral fitting recess 56. The pressing protrusion 64 is superposed on the surface of the outer peripheral edge portion of the stamper 43 disposed on the fixed side cavity forming surface 34, so that the outer peripheral portion of the stamper 43 is placed on the fixed side cavity forming surface 34. It is designed to be held.

That is, in the optical disk substrate molding die having such a structure, the inner and outer peripheral edge portions of the stamper 43 arranged on the fixed side cavity forming surface 34 are sucked and adsorbed to the fixed mold 12. With the inner and outer stamper pressing members 50 and 60 restrained and held, the movable mold 10 and the fixed mold 12 are clamped to form the molding cavity 14, and the resin of the sprue bush 36 is introduced into the molding cavity 14. The optical disk substrate is molded by injecting and filling a resin material through the hole 38, and then the male cutter 26 is used as an internal stamper pressing member 50 as a female cutter.
The inner hole 66 of the optical disc to punch out the central hole of the optical disc substrate, and after the elapse of a predetermined cooling and solidifying time, the mold is opened,
The molded product of the optical disc substrate is released by the ejector sleeve 24 and taken out, and the sprue and runner portions are released by the ejector pin 28 and taken out, whereby the desired optical disc substrate molding operation is performed.

Here, in such a mold for optical disk substrate, since the inner stamper pressing member 50 is attached to the fixed mold 12 by suction by negative pressure air, the inner stamper pressing member 50, and hence the stamper 43. The attachment / detachment to / from the fixed mold 12 can be performed extremely easily and quickly, and the stamper attachment / detachment can be easily realized.

In addition, in such an optical disk substrate molding die, there is no need to form a threaded portion for screwing on the inner stamper pressing member 50 and the size can be reduced.
The fixed mold 12 can be thinned to shorten the sprue portion, and thus the volume of the sprue portion, which requires a long cooling time due to the large wall thickness, can be reduced,
The shortening of the cooling time of the resin material and the improvement of the molding cycle and the yield can be advantageously achieved.

Furthermore, in such an optical disk substrate forming die, the inner stamper pressing member 50 has the fixed die 12
Since it is fitted into the inner peripheral side fitting concave portion 46 and assembled, even if the negative pressure suction force exerted through the air passage 48 during the molding operation is reduced or interrupted, the inner stamper retainer is pressed. The suction force between the member 50 and the bottom surface of the inner peripheral side fitting recess 46, the fitting action of the inner stamper pressing member 50 into the inner peripheral side fitting recess 46, and the like cause the inner stamper pressing member 50, and by extension, the stamper 43. The falling off from the fixed mold 12 can be effectively prevented, and the stamper 4
There is also an effect that damage such as 3 is prevented.

Further, in such an optical disk substrate forming die, since the female cutter is constituted by the edge portion of the inner hole 66 of the inner stamper pressing member 50, it is advantageous to reduce the number of parts and simplify the structure. In addition, it is possible to easily clean the female cutter portion after removing the inner stamper pressing member 50, thereby easily reducing or reducing the occurrence of defective products due to the entry of monomer gas into the female cutter portion during molding. It can be prevented.

Further, in this embodiment, since the inner stamper pressing member 50 is allowed to play a little in the direction perpendicular to the axis under the condition of being assembled to the fixed mold 12, the fixed mold 12 is allowed. Even when a misalignment occurs between the male and female cutters due to misalignment between the movable mold 10 and the movable die 10, the inner stamper pressing member 50 as the female cutter moves when the male cutter 26 is projected. By
Since the centering operation is performed by itself, shaving of male and female cutters is effectively prevented, and the punching process of the center hole of the optical disk substrate is stabilized and the durability of the cutter member is improved. It can be done. It should be noted that, at the time of the centering operation of the male and female cutters by the movement of the inner stamper pressing member 50, the resin material existing in the inner hole of the inner stamper pressing member 50 exerts a lubricating action with the male cutter 26 that is thrust into the inner hole. Therefore, a smooth centering operation can be advantageously realized. Moreover, since the eccentricity of the optical disk base is mainly determined by the male cutter, as described above,
By arranging the inner stamper pressing member 50 constituting the female cutter so as to be displaceable and aligned, it is possible to further strengthen the positioning of the male cutter with respect to the movable mold 10, and thereby the central hole of the optical disc substrate. The positioning accuracy of can be improved.

Further, in the optical disk substrate molding die of this embodiment, the stamper 43 is fixed to the fixed side cavity forming surface 34 by the positioning sleeve 40 (positioning protrusion 42) fixedly assembled to the fixed mold 12. Since the inner stamper pressing member 50 is displaced due to the alignment of the male and female cutters, the stamper 43 does not move together with the inner stamper pressing member 50, and the fixed side is held because the upper side is positioned and held. Since it can be held at a predetermined position on the cavity forming surface 34, the stamper 43 can be effectively prevented from being deformed.

Moreover, in this embodiment, the positioning protrusion 42
Since the outer peripheral side edge part of is a curved surface shape,
The stamper 43 can be easily fitted to the positioning protrusion 42, and the workability of setting the stamper can be improved.

The embodiments of the present invention have been described in detail above, but these are literal examples, and the present invention should not be construed as being limited to such specific examples.

For example, a positioning projection for positioning the stamper 43 on the fixed side cavity forming surface 34 of the fixed mold 12 is integrated with the fixed mirror block 30 and the sprue bush 36 without using a positioning sleeve. It is also possible to form it. However, it is also possible to fit the stamper 43 onto the inner stamper pressing member 50 and directly position by the inner stamper pressing member 50 without providing such a positioning protrusion.

Further, a negative pressure source and a positive pressure source can be selectively connected to the air passage 48, and when the stamper 43 is removed, the air passage 48 is connected to the positive pressure source and the inner stamper pressing member. It is also possible to apply an air blow to 50, whereby the workability of removing the stamper 43 can be further improved.

Although not listed one by one, the present invention
The present invention can be carried out in a mode in which various changes, modifications, improvements, etc. are added based on the knowledge of a person skilled in the art, and such a mode does not depart from the gist of the present invention.
Both are included within the scope of the present invention,
Needless to say.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing a main part in an embodiment of an optical disk substrate molding die having a structure according to the present invention.

FIG. 2 is an enlarged view of a main part of the optical disc substrate molding die shown in FIG.

[Explanation of symbols]

 10 movable mold 12 fixed mold 14 disk molding cavity 18 movable side cavity forming surface 26 male cutter 34 fixed side cavity forming surface 40 positioning sleeve 42 positioning protrusion 43 stamper 46 inner peripheral side fitting recess 48 air passage 50 inner stamper pressing member 54 Presser protrusion

Claims (4)

[Claims] 1. An inner side stamper holding member is detachably provided at a central portion of a cavity forming surface with respect to a fixed die forming a forming cavity by being fitted to a movable die, and the inner stamper is attached. A molding die for an optical disk substrate, in which an inner peripheral edge portion of a stamper is held on the cavity forming surface by a holding member, wherein the fixed die is provided with a fitting recess into which the inner stamper holding member is fitted, An air passage opening to the inner surface of the fitting recess is provided so that the inner stamper pressing member is sucked and fixed to the cavity forming surface side by negative pressure air, while the inner peripheral side of the inner stamper pressing member facing the movable mold is held. A molding die for an optical disc substrate, characterized in that a female cutter for punching out a central hole of the optical disc substrate is constituted by the edge portion. 2. The inner stamper pressing member is fitted in the fitting recess of the fixed mold in such a manner that it can be displaced back and forth in a direction perpendicular to the facing direction of the movable mold. Mold for optical disk substrate. 3. The stamper is positioned on the cavity forming surface by being positioned outward of the inner stamper pressing member in the direction perpendicular to the axis, protruding toward the cavity forming surface, and fitted in the center hole of the stamper. The optical disk substrate molding die according to claim 2, wherein a positioning protrusion for positioning is fixedly provided on the fixed mold. 4. An annular outer stamper pressing member is suction-fixed to the outer peripheral portion of the cavity forming surface of the fixed mold by negative pressure air, and the outer peripheral stamper pressing member causes the outer peripheral portion of the stamper to move to the cavity. The optical disk substrate molding die according to any one of claims 1 to 3, wherein the molding die is held on the forming surface.