JP2000296535A - Method and apparatus for injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the birefringence generated on the inner circumference side of a signal recording area in a disk-shaped substrate to be an optical recording medium. SOLUTION: In an injection molding apparatus in which at least a fixed mold 3 and a movable mold 5 are arranged to confront each other to form a cavity 6 having a shape corresponding to a disk-shaped substrate, and a substrate material is injected/packed into the cavity 6 to mold the substrate to be an optical recording medium, at least in one of the fixed mold 3 and the movable mold 5, the cooling efficiency of the inner circumference part side corresponding to the non-signal recording area of the substrate is made higher than that of the outer circumference part side corresponding to the signal recording area of the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed mold and a movable mold which are opposed to each other to form a cavity having a shape corresponding to a disk-shaped substrate, and a molding material is injected and filled in the cavity. The present invention relates to an injection molding apparatus and an injection molding method for producing a substrate to be an optical recording medium.

[0002]

2. Description of the Related Art A disk-shaped recording medium substrate (hereinafter referred to as a disk substrate) serving as an optical recording medium is usually manufactured by an injection molding apparatus using an injection molding method. In this disk substrate, a substantially central portion is a non-signal recording area, and an area outside the non-signal recording area is formed as a signal recording area.

[0003] The injection molding apparatus comprises a fixed mold for molding at least one main surface of the disk substrate, a movable mold that is close to and separated from the fixed mold and molds the other main surface of the disk substrate, And an outer peripheral mold for molding the outer peripheral surface. That is, in such an injection molding apparatus, a cavity having a shape corresponding to the disk substrate to be molded is formed by the fixed mold, the movable mold and the outer peripheral mold. The fixed mold is provided with a sprue bush serving as a supply path for filling the molten substrate material into the cavity. Also,
The movable mold is provided with a protruding member for pushing out the formed disk substrate from the cavity. Also,
The injection molding apparatus includes a fixed mold and / or a movable mold corresponding to a signal recording area of a disk substrate to be molded.
A so-called stamper is attached. This stamper has an uneven pattern such as pits and grooves formed thereon, and transfers the uneven pattern to a signal recording area of a disk substrate to be formed.

In the injection molding apparatus configured as described above, the movable mold moves in a direction approaching the fixed mold, and a cavity is formed by the movable mold, the fixed mold, and the outer peripheral mold. Then, the molten substrate material is filled into the cavity through the sprue bush. The filled resin material is cooled and solidified to form a disk substrate. After molding the disk substrate in this way, the injection molding apparatus moves the movable mold in a direction away from the fixed mold to expose the disk substrate. At this time, the disk substrate remains on the movable mold side. Then, the disk substrate is extruded from the movable mold by the protruding member, and is released.

[0005]

Incidentally, the above-mentioned disk substrate uses a resin material such as polycarbonate as a substrate material, and is used, for example, for disk substrates used as CDs and MOs. Further, when manufacturing such a disk substrate, it has been considered as one of the technical problems that the birefringence should be within the standard (± 100, double pulse) as a manufacturing problem from the beginning of development.

In the case of such an injection molding apparatus, when manufacturing such a disk substrate, it is necessary to increase the molding pressure of the substrate material in order to accurately transfer an uneven pattern such as pits and grooves formed on the stamper to the disk substrate. . However, in the conventional injection molding apparatus, the birefringence of the inner peripheral portion corresponding to the non-signal recording area of the disk substrate is out of the standard, and the product yield may be significantly reduced.

Further, in the injection molding apparatus, it is necessary to shorten the cooling time of the disk substrate to be molded in order to shorten the manufacturing cycle. However, in the conventional injection molding apparatus, when the cooling time of the disk substrate to be molded is shortened, the birefringence of the inner peripheral portion of the disk substrate shifts to the negative side, and as a result, the birefringence increases. there were.
For this reason, in the conventional injection molding apparatus, the manufacturing cycle cannot be shortened, and there is naturally a limit.

In view of the foregoing, the present invention has been proposed in view of the above circumstances, and by suppressing birefringence generated on the inner peripheral portion of a disk-shaped substrate serving as an optical recording medium,
An object of the present invention is to provide an injection molding apparatus and an injection molding method in which this substrate is molded with high precision and productivity is greatly improved.

[0009]

Means for Solving the Problems In order to achieve this object, the present inventors have conducted intensive studies. As a result, the birefringence generated in the inner peripheral portion of the disk-shaped substrate is reduced to the signal recording area of the substrate. It has been found that the temperature significantly changes depending on the cooling temperature between the outer peripheral side corresponding to the above and the inner peripheral side corresponding to the non-signal recording area of the substrate.

In order to achieve this object, an injection molding apparatus according to the present invention comprises a cavity having a shape corresponding to a disk-shaped substrate by abutting at least a fixed mold and a movable mold so as to face each other. An injection molding apparatus for molding a substrate to be an optical recording medium by injecting and filling a substrate material into a cavity, wherein at least one of a fixed mold and a movable mold has an outer peripheral side corresponding to a signal recording area of the substrate. Rather, the structure is such that the cooling efficiency on the inner peripheral side corresponding to the non-signal recording area of the substrate is improved.

In the injection molding apparatus according to the present invention configured as described above, the cooling efficiency on the inner peripheral side corresponding to the non-signal recording area of the substrate is more than the outer peripheral side corresponding to the signal recording area of the substrate. , The birefringence generated in the inner peripheral portion of the substrate is suppressed.

In the injection molding apparatus according to the present invention, at least one of the fixed mold and the movable mold molds a first mold member for molding an inner peripheral portion of the substrate and an outer peripheral portion of the substrate. It is preferable that the first mold member be made of a material having a higher thermal conductivity than the second mold member.

In this case, since a material having a higher thermal conductivity than the second mold member is used for the first mold member, the material of the molded substrate is located closer to the outer periphery of the molded substrate. The cooling efficiency on the peripheral side is increased, and the birefringence generated on the inner peripheral part of the substrate is suppressed.

In the injection molding apparatus according to the present invention, at least one of the fixed mold and the movable mold molds a first mold member for molding an inner peripheral portion of the substrate and an outer peripheral portion of the substrate. A second mold member, wherein the first mold member comprises:
It is preferable that the substrate is formed so as to protrude more toward the cavity than the second mold member, and the inner peripheral portion of the substrate is formed to be thinner than the outer peripheral portion.

In this case, since the thickness of the inner peripheral portion of the molded substrate is smaller than the thickness of the outer peripheral portion, the inner peripheral portion of the molded substrate is more than the outer peripheral side of the molded substrate. The cooling efficiency on the side is increased, and the birefringence generated in the inner peripheral portion of the substrate is suppressed.

Further, in the injection molding apparatus according to the present invention, the first molding machine is provided inside the portion for molding the inner peripheral portion of the substrate.
And a second channel disposed inside the portion for forming the outer peripheral portion of the substrate. The first channel has a cooling means circulated through the second channel. Preferably, a coolant having a temperature different from that of the coolant is circulated. Thereby, the inner peripheral portion and the outer peripheral portion of the formed substrate can be cooled at different temperatures.

It is preferable that the first flow path circulates a cooling liquid whose temperature is lower than that of the cooling liquid circulated in the second flow path. In this case, the cooling efficiency on the inner peripheral side of the molded substrate is higher than that on the outer peripheral side of the molded substrate, and the birefringence generated on the inner peripheral portion of the substrate is suppressed.

Further, in the injection molding apparatus according to the present invention, the first molding machine is provided inside the portion for molding the inner peripheral portion of the substrate.
And a second channel disposed inside a portion for forming the outer peripheral portion of the substrate. The first channel is closer to the cavity than the second channel. Is preferably provided.

In this case, since the first flow path is provided on the cavity side with respect to the second flow path, cooling on the inner peripheral side of the substrate to be molded is more efficient than on the outer peripheral side of the substrate to be molded. Efficiency is enhanced, and birefringence generated in the inner peripheral portion of the substrate is suppressed.

Further, in the injection molding method according to the present invention for achieving this object, at least a fixed mold and a movable mold are opposed to each other so as to face each other to form a cavity having a shape corresponding to a disk-shaped substrate. An injection molding method for molding a substrate to be an optical recording medium by injecting and filling a substrate material into a cavity, wherein the substrate corresponds to a non-signal recording area of the substrate from an outer peripheral side corresponding to a signal recording area of the substrate. It is characterized in that the cooling efficiency on the inner peripheral side is increased.

As described above, in the injection molding method according to the present invention, the cooling efficiency on the inner peripheral side corresponding to the non-signal recording area of the substrate is made higher than on the outer peripheral side corresponding to the signal recording area of the substrate. Thereby, birefringence generated in the inner peripheral portion of the substrate can be suppressed.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. An injection molding apparatus to which the present invention is applied is for producing a disk-shaped substrate (hereinafter, referred to as a disk substrate) serving as an optical recording medium. In this disk substrate, a substantially central portion is a non-signal recording area, and an area outside the non-signal recording area is formed as a signal recording area. In addition, the injection molding apparatus to which the present invention is applied may be configured such that at least one of the fixed mold and the movable mold has an inner peripheral side corresponding to a non-signal recording area rather than an outer peripheral side corresponding to a signal recording area of the disk substrate. It has a structure that enhances the cooling efficiency.

First, an injection molding apparatus 1 shown in FIG. 1 will be described as a first embodiment of the present invention.

This injection molding apparatus 1 comprises: a fixed mold 3 having a fixed mirror 2 for forming one main surface of a disk substrate;
A movable mold 5 having a movable mirror 4 for molding the other main surface of the disk substrate. The fixed mold 3 and the movable mold 5 form a cavity 6 having a shape corresponding to a disk substrate formed in a mold clamped state.

The fixed mirror 2 is provided with a stamper 7 on the surface constituting the cavity 6. The stamper 7 has an uneven pattern such as pits and grooves formed thereon, and transfers the uneven pattern to a signal recording area of a disk substrate to be formed.

An outer peripheral ring 8 for forming the outer peripheral surface of the disk substrate is attached to the movable mirror 4. The outer peripheral ring 8 has a substantially annular shape, and is attached so as to be fitted on the outer periphery of a surface of the movable mirror 4 that forms the cavity 6.

The fixed mold 3 is fixed by being attached to a fixed plate (not shown). On the other hand, the movable mold 5 is attached to a movable plate (not shown), is disposed to face the fixed mold 3 and is freely movable close to and away from the fixed mold 3 by guide means and driving means. It has been.
In the injection molding apparatus 1, when the movable mold 5 moves in a direction approaching the fixed mold 3 and is clamped, the outer peripheral ring 8 attached to the movable mirror 5 is attached to the fixed mirror 2. The above-described cavity 6 is formed by abutting the attached stamper 7.

The stationary mold 3 has a sprue bush 9 at a substantially central portion thereof serving as a supply path for supplying a substrate material made of a resin material such as polycarbonate into the cavity 6.
And an inner stamper holder 10 attached to the outer periphery of the sprue bush 9 and holding the inner periphery of the stamper 7.
And The fixed mold 3 has an outer peripheral side stamper holder 11 that presses the outer peripheral side of the stamper 7 on the outer peripheral portion.
Is provided.

The sprue bush 9 is connected to a material supply device (not shown) at an end opposite to an end which is connected to the cavity 6. And sprue bush 9
Is a supply path when the substrate material heated and melted from the material supply device is supplied into the cavity 6.

Further, the inner peripheral side stamper holder 10 is formed with a protrusion 10 a formed to protrude into the cavity 6. The protrusion 10a formed on the inner peripheral side stamper holder 10 has a substantially annular shape slightly larger in diameter than the center hole of the stamper 7. Accordingly, the inner peripheral portion of the stamper 7 is held by the inner peripheral stamper holder 10 by the projections 10 a of the inner peripheral stamper holder 10 being engaged with the inner peripheral wall of the center hole, and the stamper 7 is attached to the fixed mirror 2. Can be

The outer peripheral side stamper holder 11 has a protrusion 11 a formed to protrude into the cavity 6. The protrusion 11 a formed on the outer peripheral side stamper holder 11 has a substantially annular shape having a center hole slightly larger in diameter than the outer diameter of the disk substrate and slightly smaller in diameter than the outer diameter of the stamper 7. . The outer peripheral side stamper holder 11 is assembled to the fixed mold 3 by mounting screws or the like. Therefore, the outer peripheral edge of the stamper 7 is relatively engaged with the projection 11 a of the outer peripheral stamper holder 11, so that the outer peripheral portion is held by the outer peripheral stamper holder 11 and attached to the fixed mirror 2.

The movable mold 5 has a punch 12 for cutting the center of the disk substrate to be formed, an extrusion pin 13 for pushing out the center cut by the punch 12, and a formed disk at substantially the center. Eject pins 14 for releasing the substrate from the movable mold 5.

The punch 12 cuts a runner portion of the solidified substrate material supplied from the sprue bush 9 into the cavity 6, and has an outer diameter substantially the same as the center hole of the disk substrate to be formed. Have. The punch 12 can be moved in a direction protruding into the cavity 6 by a guide unit or a driving unit (not shown). Therefore, when the substrate material filled in the cavity 6 is in a semi-molten state, the punch 12 cuts the runner portion to form a center hole.

The push-out pin 13 is formed in a rod shape and is disposed at the center of the punch 12. This pushing pin 13
The guide 12 and the driving means (not shown) can be moved in the direction of protruding into the cavity 6.
To remove the cut portion. Therefore, after the substrate material filled in the cavity 6 is solidified, the extrusion pin 13 is pushed out, so that the runner part and the sprue, that is, the substrate material accumulated in the supply path of the runner part and the sprue bush 9 are formed. And can be eliminated.

The eject pin 14 has a cylindrical shape having an inner diameter substantially the same as the outer diameter of the punch 12, and is disposed so as to surround the punch 12. The eject pin 14 can be moved in a direction in which the eject pin 14 protrudes into the cavity 6 by guide means or drive means (not shown). Therefore, after the cavity 6 is filled with the substrate material and the center hole of the disk substrate is formed as described above, the eject pins 14 press the inner peripheral side of the disk substrate to remove the disk substrate from the movable mold 5. Release the mold.

In addition, the injection molding apparatus 1 has cooling grooves 15 in the fixed mold 3 and the movable mold 5, respectively. The cooling groove 15 is located inside the surface of the fixed mirror 2 and the movable mirror 4 that constitutes the cavity 6, and is a groove formed in an annular shape on the surface that comes into contact with the fixed mold 3 and the movable mold 5, respectively. It is formed as. The cooling groove 15 is connected to a cooling liquid circulation device (not shown). And cooling groove 15
Then, as schematically shown in FIG. 2, when the coolant is supplied from the inner peripheral side (IN side shown in the figure) by the coolant circulating device, it is circulated to the outer peripheral side (OUT side shown in the figure). Then, it is returned to the coolant circulation device again. Therefore, the coolant circulating in the cooling groove 15 causes the cavity 6
The substrate material injected into it, ie the disk substrate to be molded, can be cooled.

In this injection molding apparatus 1, as shown in FIG. 1, the movable mirror 4 forms a first mold member 16 for molding an inner peripheral portion corresponding to a non-signal recording area of the disk substrate, and a signal of the disk substrate. Second forming the outer peripheral portion corresponding to the recording area
And the mold member 17. That is, in the injection molding apparatus 1, of the surfaces constituting the cavity 6 of the movable mirror 4, the surface for molding the inner peripheral portion corresponding to the non-signal recording area of the disk substrate is constituted by the first mold member 16, The surface on which the outer peripheral portion corresponding to the signal recording area of the disk substrate is formed is constituted by the second mold member 17.
For the first mold member 16, a material having a higher thermal conductivity than the second mold member 17 is used. For example, Be-Cu
Is used. On the other hand, the second mold member 17
Is made of a material having a lower thermal conductivity than the first mold member 16, for example, stainless steel (SUS).

In the injection molding apparatus 1 configured as described above, the molten substrate material is injected and filled into the cavity through the sprue bush 9. And cavity 6
The substrate material filled therein is cooled and solidified to form a disk substrate.

In this case, in the injection molding apparatus 1, the first mold member 16 and the second mold member 1 constituting the movable mirror 4 are formed.
7 are made of a different material, and a material having a higher thermal conductivity than the second mold member 17 is used for the first mold member 16. Therefore, in the injection molding apparatus 1, the cooling efficiency on the inner peripheral side of the disk substrate to be molded can be higher than that on the outer peripheral side. Thereby, the injection molding apparatus 1
Thus, the occurrence of birefringence in the inner peripheral portion of the disk substrate can be suppressed.

Therefore, in the injection molding apparatus 1, the range of molding conditions such as increasing the molding pressure of the substrate material can be widened, and the disk substrate can be molded with high precision. It can be greatly improved. Further, in the injection molding apparatus 1, the cooling time of the disk substrate to be molded can be shortened, and the manufacturing cycle can be shortened, so that the productivity can be greatly improved.

In the injection molding apparatus 1, the movable mirror 4
Is the first mold member 16 for molding the inner peripheral portion of the disk substrate.
And a second mold member 1 for molding the outer peripheral portion of the disk substrate
7, but is not limited to this configuration. For example, similarly to the movable mirror 4, the fixed mirror 2 is formed with a first mold member for forming an inner peripheral portion corresponding to a non-signal recording area of the disk substrate and an outer peripheral portion corresponding to a signal recording area of the disk substrate. And a second mold member.

Next, an injection molding apparatus 20 shown in FIG. 3 will be described as a second embodiment of the present invention. In the following description, the same parts as those of the injection molding apparatus 1 will not be described, and the same reference numerals will be used in the drawings.

In the injection molding apparatus 20, the movable mirror 4
A first mold member 21 for molding an inner peripheral portion corresponding to a non-signal recording area of a disk substrate, and a second mold member 22 for molding an outer peripheral portion corresponding to a signal recording area of the disk substrate.
It is composed of That is, in the injection molding apparatus 20, of the surfaces constituting the cavity 6 of the movable mold 5, the surface for molding the inner peripheral portion corresponding to the non-signal recording area of the disk substrate is constituted by the first mold member 21. The surface for forming the outer peripheral portion corresponding to the signal recording area of the disk substrate is the second
Of the mold member 22. In addition, the first mold member 21 is smaller than the second mold member 22 in the cavity 6.
It protrudes from the side. For this reason, in the cavity 6, the thickness a of the inner peripheral portion corresponding to the non-signal recording area of the molded disk substrate is larger than the thickness b of the outer peripheral portion corresponding to the signal recording area of the molded disk substrate. It is shaped to be thin.

The injection molding apparatus 20 configured as described above
Then, the molten substrate material is injected and filled into the cavity through the sprue bush 5. Then, the substrate material filled in the cavity 6 is cooled and solidified to form a disk substrate.

In this case, in the injection molding apparatus 20, the thickness a of the inner peripheral portion of the disk substrate to be molded is formed smaller than the thickness b of the outer peripheral portion. For this reason, the injection molding apparatus 20
Thus, the cooling efficiency of the inner peripheral side of the molded disk substrate can be higher than that of the outer peripheral side. Thereby, in the injection molding device 20, it is possible to suppress the occurrence of birefringence in the inner peripheral portion of the disk substrate.

Therefore, in this injection molding apparatus 20,
The same effects as those of the injection molding apparatus 1 described above can be obtained.

Next, an injection molding apparatus 30 shown in FIG. 4 will be described as a third embodiment of the present invention. In the following description, portions that are the same as those of the injection molding apparatus 1 described above will not be described, and will be denoted by the same reference numerals in the drawings.

In the injection molding apparatus 30, a cooling circuit 3 is provided to the fixed mirror 2 and the movable mirror 4 as cooling means.
1 is provided. The cooling circuit 31 includes a first cooling groove 32 located inside a surface forming an inner peripheral portion corresponding to a non-signal recording area of the disk substrate among the surfaces constituting the cavity 6, and a signal of the disk substrate. Second cooling groove 33 located inside the surface for forming the outer peripheral portion corresponding to the recording area
It is composed of The first cooling groove 32 and the second cooling groove 33 are located inside the surfaces of the fixed mirror 2 and the movable mirror 4 that constitute the cavity 6, and are in contact with the fixed mold 3 and the movable mold 5, respectively. It is formed as a groove formed in an annular shape on the surface to be formed. Also, the cooling circuit 31
Is connected to a cooling liquid circulating device (not shown) and can independently control the cooling liquid circulated in the first cooling groove 32 and the second cooling groove 33. Further, in the cooling circuit 31, a cooling liquid whose temperature is lower than that of the cooling liquid circulated through the second cooling groove 33 is circulated through the first cooling groove 32.

Here, a circulation path of the coolant circulating in the first cooling groove 32 and the second cooling groove 33 will be described with reference to FIG. 5 schematically shown.

In the cooling circuit 31, the cooling liquid is supplied from one side of the first cooling groove 32 (IN 1 shown in the drawing) by the cooling circulation device.
Side), the first cooling groove 32 is circulated to the other side (OUT1 side shown in the figure) and returned to the cooling liquid circulation device again. Further, in the cooling circuit 31, when the coolant is supplied from the inner peripheral side (IN2 side shown in the figure) of the second cooling groove 33 by the coolant circulating device, the second cooling groove 3
3 is circulated to the outer peripheral side (OUT2 side shown in the figure) and returned to the coolant circulating device again.

The injection molding apparatus 30 configured as described above
Then, the molten substrate material is injected and filled into the cavity through the sprue bush 9. Then, the substrate material filled in the cavity 6 is cooled and solidified to form a disk substrate.

In this case, in the injection molding apparatus 30, the inner peripheral portion of the disk substrate on which the first cooling groove 32 is formed is cooled, and the outer peripheral portion of the disk substrate on which the second cooling groove 33 is formed is cooled. It will be. Further, the first cooling groove 32 circulates a cooling liquid at a lower temperature than the cooling liquid circulated in the second cooling groove 33. For this reason, in the injection molding device 30, the cooling efficiency on the inner peripheral side of the disk substrate to be molded can be higher than that on the outer peripheral side. Thereby, in the injection molding apparatus 30, it is possible to suppress the occurrence of birefringence in the inner peripheral portion of the disk substrate.

Therefore, in this injection molding apparatus 30,
The same effects as those of the injection molding apparatus 1 described above can be obtained.

Next, an injection molding apparatus 40 shown in FIG. 6 will be described as a fourth embodiment of the present invention. In the following description, the same parts as those of the injection molding apparatus 1 will not be described, and will be denoted by the same reference numerals in the drawings.

In the injection molding apparatus 40, cooling grooves 41 are provided on the fixed mirror 2 and the movable mirror 4 as cooling means, respectively.
Is provided. The cooling groove 41 is located inside the surface of the fixed mirror 2 and the movable mirror 4 that constitutes the cavity 6, and is formed in an annular shape on the surface that comes into contact with the fixed mold 3 and the movable mold 5, respectively. It is formed as.
In the cooling groove 41, the depth of the inner peripheral groove 42 on the inner peripheral side corresponding to the non-signal recording area of the disk substrate among the surfaces constituting the cavity 6 corresponds to the signal recording area of the disk substrate. It is formed deeper than the depth of the outer peripheral groove 43 on the outer peripheral portion side. For this reason, in the injection molding device 40, of the cooling grooves 41 formed in the fixed mirror 2 and the movable mirror 4, the inner peripheral groove 42 is provided closer to the cavity 6 than the outer peripheral groove 43.

The cooling groove 41 is connected to a cooling liquid circulation device (not shown). Then, in the cooling groove 41, FIG.
As schematically shown in FIG. 5, when the coolant is supplied from the inner circumferential groove 42 side (IN side shown in the figure) by the coolant circulation device,
It is circulated to the outer peripheral groove 43 side (OUT side shown in the figure) and returned to the coolant circulating device again.

The injection molding apparatus 40 configured as described above
Then, the molten substrate material is injected and filled into the cavity through the sprue bush 9. Then, the substrate material filled in the cavity 6 is cooled and solidified to form a disk substrate.

In this case, in the injection molding apparatus 40, the inner peripheral groove 42 of the cooling groove 41 is provided closer to the cavity 6 than the outer peripheral groove 43. Therefore, in the injection molding apparatus 40, the cooling efficiency on the inner peripheral side of the disk substrate to be molded can be higher than that on the outer peripheral side. This allows
In the injection molding device 40, it is possible to suppress the occurrence of birefringence in the inner peripheral portion of the disk substrate.

Therefore, in this injection molding apparatus 40,
The same effects as those of the injection molding apparatus 1 described above can be obtained.

As described above, in the injection molding method to which the present invention is applied, the inner peripheral portion corresponding to the non-signal recording area of the disk substrate to be molded is more than the outer peripheral side corresponding to the signal recording region of the disk substrate to be molded. By increasing the cooling efficiency on the part side, it is possible to suppress the birefringence generated in the inner peripheral part of the disk substrate to be formed.

Therefore, according to the present invention, the range of molding conditions such as increasing the molding pressure of the substrate material can be expanded, and the disk substrate can be molded with high precision, so that the product yield can be greatly reduced. Can be improved.

Further, according to the present invention, the cooling time of the disk substrate to be formed can be shortened and the manufacturing cycle can be shortened, so that the productivity can be greatly improved.

Although the injection molding apparatus to which the present invention is applied has been described in detail with reference to the first to fourth embodiments, the present invention is not necessarily limited to such a configuration. For example, by combining these first to fourth embodiments, the non-signal recording area of the molded disk substrate is located closer to the outer peripheral side corresponding to the signal recording area of the molded disk substrate. A configuration may be adopted in which the cooling efficiency on the corresponding inner peripheral side is increased.

[0064]

As described above in detail, according to the present invention, the cooling efficiency on the inner peripheral side, which is a non-signal recording area of the substrate, is higher than that on the outer peripheral side, which is a signal recording area of the substrate. Thereby, the birefringence generated in the inner peripheral portion of the substrate can be suppressed.

Therefore, according to the present invention, the range of molding conditions such as increasing the molding pressure of the substrate material can be widened, and the substrate can be molded with high precision, so that the product yield is greatly improved. Can be done.

According to the present invention, the cooling time of the substrate to be formed can be shortened, and the manufacturing cycle can be shortened, so that the productivity can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of a configuration of an injection molding apparatus shown as a first embodiment of the present invention.

FIG. 2 is a view schematically showing a circulation path of a coolant circulating in a cooling groove of the injection molding apparatus.

FIG. 3 is a vertical sectional view of a main part showing a configuration of an injection molding apparatus shown as a second embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a main part showing a configuration of an injection molding apparatus shown as a third embodiment of the present invention.

FIG. 5 is a view schematically showing a circulation path of a coolant circulating in a first cooling groove and a second cooling groove which constitute a cooling circuit of the injection molding apparatus.

FIG. 6 is a vertical sectional view of a main part showing a configuration of an injection molding apparatus shown as a fourth embodiment of the present invention.

FIG. 7 is a diagram schematically showing a circulation path of a coolant circulating in a cooling groove of the injection molding apparatus.

[Explanation of symbols]

1 injection molding device, 2 fixed mirror, 3 fixed mold, 4
Movable mirror, 5 movable mold, 6 cavity, 7 stamper, 8 outer ring, 16 first mold member, 17
Second mold member, 20 injection molding device, 21 first mold member, 22 second mold member, 30 injection molding device,
31 cooling circuit, 32 first cooling groove, 33 second cooling groove, 40 injection molding device, 41 cooling groove, 42 inner circumferential groove, 43 outer circumferential groove

[Procedure amendment]

[Submission date] June 7, 1999 (1999.6.7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

In the case of such an injection molding apparatus, when manufacturing such a disk substrate, it is necessary to increase the molding pressure of the substrate material in order to accurately transfer an uneven pattern such as pits and grooves formed on the stamper to the disk substrate. . However, in the conventional injection molding apparatus, the birefringence on the inner peripheral side in the signal recording area of the disk substrate is out of the standard, and the product yield may be greatly reduced.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

Further, in the injection molding apparatus, it is necessary to shorten the cooling time of the disk substrate to be molded in order to shorten the manufacturing cycle. However, in the conventional injection molding apparatus, when the cooling time of the disk substrate to be molded is reduced, the birefringence on the inner peripheral side in the signal recording area of the disk substrate shifts to the negative side, and as a result, the birefringence of the In some cases increased. For this reason, in the conventional injection molding apparatus, the manufacturing cycle cannot be shortened, and there is naturally a limit.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

Accordingly, the present invention has been proposed in view of such a conventional situation, and it is an object of the present invention to suppress birefringence occurring on the inner peripheral side of a signal recording area in a disk-shaped substrate serving as an optical recording medium. Accordingly, an object of the present invention is to provide an injection molding apparatus and an injection molding method in which this substrate is molded with high precision and productivity is greatly improved.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

[0009]

Means for Solving the Problems In order to achieve this object, the inventors of the present invention have conducted intensive studies, and as a result, the signal is generated on the inner peripheral side of the signal recording area on the disk-shaped substrate serving as the optical recording medium. It has been found that the birefringence changes significantly due to the difference in cooling temperature between the outer peripheral side corresponding to the signal recording area of the substrate and the inner peripheral side corresponding to the non-signal recording area of the substrate.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

In the injection molding apparatus according to the present invention configured as described above, the inner peripheral portion corresponding to the non-signal recording region of the substrate is closer to the inner peripheral portion corresponding to the signal recording region of the substrate to be molded. The birefringence generated on the inner peripheral side of the signal recording area on the substrate is suppressed by increasing the cooling efficiency of the substrate.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

In the injection molding apparatus according to the present invention, at least one of the fixed mold and the movable mold is provided with a first mold member for molding an inner peripheral side corresponding to a non-signal recording area of the substrate. A second mold member for molding the outer peripheral side corresponding to the signal recording area of the substrate, and a material having a higher thermal conductivity than the second mold member is used for the first mold member. Preferably.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

In this case, since a material having a higher thermal conductivity than the second mold member is used for the first mold member, the first mold member is located closer to the outer peripheral portion corresponding to the signal recording area of the substrate to be molded. The cooling efficiency on the inner peripheral side corresponding to the non-signal recording area of the substrate is increased, and the birefringence generated on the inner peripheral side of the signal recording area on the substrate is suppressed.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

In the injection molding apparatus according to the present invention, at least one of the fixed mold and the movable mold is provided with a first mold member for molding an inner peripheral side corresponding to a non-signal recording area of the substrate. And a second mold member for molding the outer peripheral side corresponding to the signal recording area of the substrate, and the first mold member comprises:
The substrate is formed so as to protrude more toward the cavity than the second mold member, and the substrate is formed such that the thickness on the inner peripheral side corresponding to the non-signal recording area is smaller than the thickness on the outer peripheral side corresponding to the signal recording area. Is preferred.

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

In this case, since the thickness of the substrate on the inner peripheral side corresponding to the non-signal recording area is formed smaller than the thickness on the outer peripheral side corresponding to the signal recording area, the signal recording area of the substrate is reduced. The cooling efficiency on the inner peripheral side corresponding to the non-signal recording area of the substrate is higher than that on the outer peripheral side corresponding to the above, and birefringence occurring on the inner peripheral side of the signal recording area on the substrate is suppressed. .

[Procedure amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

Further, in the injection molding apparatus according to the present invention, the first flow path provided inside the portion for molding the inner peripheral side corresponding to the non-signal recording area of the substrate, and the signal flow of the substrate. A cooling means comprising a second flow path disposed inside a portion forming the outer peripheral portion corresponding to the recording area, and the first flow path is circulated through the second flow path Preferably, a coolant having a temperature different from that of the coolant is circulated. Thus, the inner peripheral side corresponding to the non-signal recording area of the substrate to be formed and the outer peripheral side corresponding to the signal recording area of the substrate can be cooled at different temperatures.

[Procedure amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

It is preferable that the first flow path circulates a cooling liquid whose temperature is lower than that of the cooling liquid circulated in the second flow path. In this case, the cooling efficiency of the inner peripheral side corresponding to the non-signal recording area of the substrate is higher than that of the outer peripheral side corresponding to the signal recording area of the substrate to be formed, and the inner periphery of the signal recording area of the substrate is improved. Birefringence generated on the part side is suppressed.

[Procedure amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

Further, in the injection molding apparatus according to the present invention, the first flow path provided inside the portion for molding the inner peripheral side corresponding to the non-signal recording area of the substrate, A cooling means comprising a second flow path disposed inward of a portion forming the outer peripheral portion corresponding to the recording area, wherein the first flow path is closer to the cavity than the second flow path. Preferably, it is provided.

[Procedure amendment 14]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction contents]

In this case, since the first flow path is provided on the cavity side with respect to the second flow path, the non-signal flow of the substrate is higher than the outer peripheral side corresponding to the signal recording area of the substrate to be formed. The cooling efficiency on the inner peripheral side corresponding to the recording area is enhanced, and the birefringence generated on the inner peripheral side of the non-signal recording area on the substrate is suppressed.

[Procedure amendment 15]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction contents]

As described above, in the injection molding method according to the present invention, the cooling efficiency on the inner peripheral side corresponding to the non-signal recording area of the substrate is made higher than on the outer peripheral side corresponding to the signal recording area of the substrate. Thereby, birefringence generated on the inner peripheral side of the signal recording area on the substrate can be suppressed.

[Procedure amendment 16]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction contents]

In this case, in the injection molding apparatus 1, the first mold member 16 and the second mold member 1 constituting the movable mirror 4 are formed.
7 are made of a different material, and a material having a higher thermal conductivity than the second mold member 17 is used for the first mold member 16. Therefore, in the injection molding apparatus 1, the cooling efficiency on the inner peripheral side corresponding to the non-signal recording area of the disk substrate to be molded is higher than that on the outer peripheral side corresponding to the signal recording area of the disk substrate to be molded. be able to. Thereby, in the injection molding apparatus 1, it is possible to suppress the birefringence occurring on the inner peripheral side of the signal recording area on the disk substrate.

[Procedure amendment 17]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction contents]

In the injection molding apparatus 1, the movable mirror 4
A first mold member 16 for molding the inner peripheral side corresponding to the non-signal recording area of the disk substrate, and a second mold member 1 for molding the outer peripheral side corresponding to the signal recording area of the disk substrate
7, but is not necessarily limited to such a configuration. For example, similarly to the movable mirror 4, the fixed mirror 2 is formed with a first mold member for molding an inner peripheral side corresponding to a non-signal recording area of the disk substrate, and an outer peripheral side corresponding to a signal recording area of the disk substrate. And a second mold member for molding the second mold member.

[Procedure amendment 18]

[Document name to be amended] Statement

[Correction target item name] 0045

[Correction method] Change

[Correction contents]

In this case, in the injection molding apparatus, the thickness a on the inner peripheral side corresponding to the non-signal recording area of the disk substrate is formed smaller than the thickness b on the outer peripheral side corresponding to the signal recording area. Therefore, in the injection molding apparatus 20, the cooling efficiency on the inner peripheral side corresponding to the non-signal recording area of the disk substrate to be molded is higher than that on the outer peripheral side corresponding to the signal recording area of the disk substrate to be molded. be able to. As a result, in the injection molding apparatus 20, it is possible to suppress the occurrence of birefringence on the inner peripheral side of the signal recording area on the disk substrate to be molded.

[Procedure amendment 19]

[Document name to be amended] Statement

[Correction target item name] 0052

[Correction method] Change

[Correction contents]

In this case, in the injection molding device 30, the first cooling groove 32 cools the inner peripheral side corresponding to the non-signal recording area of the disk substrate to be molded, and the outer peripheral side corresponding to the signal recording area. The second cooling groove 33 cools. Further, the first cooling groove 32 circulates a cooling liquid at a lower temperature than the cooling liquid circulated in the second cooling groove 33. Therefore, in the injection molding apparatus 30, the cooling efficiency on the inner peripheral side corresponding to the non-signal recording area of the disk substrate to be molded is higher than that on the outer peripheral side corresponding to the signal recording area of the disk substrate to be molded. be able to. Thus, in the injection molding apparatus 30, birefringence generated on the inner peripheral side of the signal recording area on the disk substrate to be molded can be suppressed.

[Procedure amendment 20]

[Document name to be amended] Statement

[Correction target item name] 0058

[Correction method] Change

[Correction contents]

In this case, in the injection molding device 40, the inner circumferential groove 42 of the cooling groove 41 is smaller than the outer circumferential groove 43 in the cavity 6.
It is provided on the side. Therefore, the injection molding device 40
Thus, the cooling efficiency on the inner peripheral side corresponding to the non-signal recording area of the molded disk substrate can be higher than that on the outer peripheral side corresponding to the signal recording area of the molded disk substrate. Thus, in the injection molding apparatus 40, it is possible to suppress the birefringence occurring on the inner peripheral side of the signal recording area on the disk substrate to be molded.

[Procedure amendment 21]

[Document name to be amended] Statement

[Correction target item name] 0064

[Correction method] Change

[Correction contents]

[0064]

As described above in detail, according to the present invention, the inner peripheral side corresponding to the non-signal recording area of the substrate is more than the outer peripheral side corresponding to the signal recording area of the substrate to be molded. By increasing the cooling efficiency of the substrate, it is possible to suppress birefringence occurring on the inner peripheral side of the signal recording area on the substrate.

[Procedure amendment 22]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

[Procedure amendment 23]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Hideaki Yoshimura 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo F-term in Sony Disk Technology Co., Ltd. (reference) 4F202 AG05 AH79 AJ12 AK13 AM32 CA11 CB01 CK06 CK35 CK84 CM02 CN05 CN13 CN14 CN22 5D121 DD05 DD18

Claims (7)

[Claims] At least a fixed mold and a movable mold are opposed to each other so as to face each other to form a cavity having a shape corresponding to a disk-shaped substrate, and a substrate material is injected and filled into the cavity to form an optical recording medium. An injection molding apparatus for molding a substrate to be formed, wherein at least one of the fixed mold and the movable mold is closer to a non-signal recording area of the substrate than an outer peripheral side corresponding to a signal recording area of the substrate. An injection molding apparatus having a structure for increasing the cooling efficiency of a corresponding inner peripheral side. 2. A method according to claim 1, wherein at least one of the fixed mold and the movable mold has a first mold member for molding an inner peripheral portion of the substrate and a second mold member for molding an outer peripheral portion of the substrate. The injection molding apparatus according to claim 1, wherein a material having a higher thermal conductivity than the second mold member is used for the first mold member. 3. A method according to claim 1, wherein at least one of the fixed mold and the movable mold has a first mold member for molding an inner peripheral portion of the substrate and a second mold member for molding an outer peripheral portion of the substrate. The first mold member is protruded more toward the cavity than the second mold member, and the substrate is formed such that an inner peripheral portion thereof is thinner than an outer peripheral portion thereof. The injection molding apparatus according to claim 1, wherein: 4. A first flow path provided inside a portion for forming an inner peripheral portion of the substrate, and a second flow passage provided inside a portion for forming an outer peripheral portion of the substrate. 2. A cooling means comprising: a cooling means having a temperature different from a cooling liquid circulated through the second flow path in the first flow path. Injection molding equipment. 5. The injection molding according to claim 4, wherein a cooling liquid whose temperature is lower than that of the cooling liquid circulated in the second flow path is circulated in the first flow path. apparatus. 6. A first flow path provided inside a portion for forming an inner peripheral portion of the substrate, and a second flow passage provided inside a portion for forming an outer peripheral portion of the substrate. 2. The injection molding apparatus according to claim 1, further comprising a cooling unit comprising: the first flow path is provided closer to the cavity than the second flow path. 7. An optical recording medium by forming a cavity having a shape corresponding to a disk-shaped substrate by abutting at least a fixed mold and a movable mold so as to face each other, and injecting and filling a substrate material into the cavity. An injection molding method for molding a substrate to be formed, wherein the cooling efficiency on the inner peripheral side corresponding to the non-signal recording area of the substrate is higher than on the outer peripheral side corresponding to the signal recording area of the substrate. Injection molding method.