JP3192174B2 - Mold for forming optical disk substrate and method for manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a molding die of the optical disc substrate and relates to a manufacturing method thereof, (referred to simply as an optical disc or less) forming a particular disc-shaped high-density information recording carrier of the optical type disc substrates such thin type Mold and mold suitable for
It relates to a manufacturing method .

[0002]

2. Description of the Related Art First, a molding die for molding a conventional optical disk substrate and an optical disk substrate formed by the molding die will be described with reference to FIGS. FIG.
Is a sectional view showing an example of a molding die for molding a conventional optical disk substrate, FIG. 17 is a sectional view showing another example of a molding die for molding a conventional optical disk substrate, and FIG. FIG. 19 is a partially cut perspective view showing
20 is a partially enlarged cross-sectional view of a portion C, FIG. 20 is a cross-sectional view when the thickness of the conventional optical disc substrate is assumed to be thin, and FIG. 21 is another example when the thickness of the conventional optical disc substrate is assumed to be thin. It is sectional drawing.

As a conventional mold for molding an optical disk substrate, a mold having a structure as shown in FIGS. 16 and 17 is generally used. The molding die shown in FIG. 16 constitutes a split mold, has a molding cavity 3 formed by a movable die 1 and a fixed die 2, and a part of the surface of the molding cavity (the movable die 1 in the drawing). A stamper 4 having sub-micron-order information pits, tracks, and the like on its surface is attached to the surface. That is, the inner diameter side of the stamper 4 is moved to the information surface side 4a of the stamper 4 by the claw 5a of the inner peripheral stamper holder 5.
Of the stamper 4 is fixed to the mirror block 6, and the outer diameter side of the stamper 4 is similarly attached to the mirror block 6 by the outer peripheral stamper holder 7. Japanese Patent Laid-Open Publication No. Hei.
-92609.

At the center of the movable mirror block 6, an ejector ring 8 is provided inside the inner peripheral stamper holder 5 for projecting a molded product when releasing the mold, and a gate for punching an inner circle of the molded product is provided inside the ejector ring 8. A cut punch 14 is provided, and an ejector pin 15 for projecting a sprue portion is provided at the center. Also, the inner peripheral stamper holder 5
Is provided with an annular air slit 9.
The resin is injected into the molding cavity 3 through the sprue 10.

FIG. 17 shows another conventional injection mold. In the injection molding die shown in FIG. 17, the outer peripheral ring 11 is provided on the fixed die 2 shown in FIG. 16, and the opposing surface comes into contact with the tapered inner peripheral surface of the outer peripheral stamper holder 7 so that the outer peripheral end surface of the molding cavity 3 is formed. It is stipulated.
At the center of the fixed mirror block 12, a mold release mechanism 16 for a molded product is provided on the outer peripheral side of the sprue bush 13. As a technique relating to this mold structure, for example, a technique described in Japanese Patent Application Laid-Open No. 1-264822 is known.

A method for forming a disk substrate will be described with reference to the mold shown in FIG. First, a fixed die 2 is mounted on a fixed die plate for mounting a mold of an injection molding machine (not shown).
The movable mold 1 is attached to the movable die plate. Movable mold 1
After the mold 2 is closed, the resin melted by heating is injected into the cavity 3 through the sprue 10 by an injection molding machine, and the information provided on the stamper 4 is transferred to the resin and solidified by cooling. After solidification, the mold clamping mechanism is driven to separate the movable mold 1 from the fixed mold 2 and open the mold.
Air slit 9a provided near the center of fixed mold 2
Compressed air is supplied from the fixed mirror block 12 to release the formed substrate.

Therefore, the molded plastic substrate is opened while being attached to the surface of the stamper 4 of the movable mold 1. After the mold is completely opened, the ejector pin 15 and the ejector ring 5 are pushed out by ejecting a mechanical ejector rod while ejecting compressed air from an air slit 9 provided near the center of the movable mold 1 to eject the substrate. Release the mold completely. Related technologies of this type include, for example, Japanese Patent Application Laid-Open No. 1-2648.
No. 22 publication.

In order to improve the transferability of minute irregularities, which are information of a stamper, an injection compression molding method for compressing the resin cast in the cavity 3 in a direction to reduce the cavity volume before solidifying, Further, there is a stamper surface preferential release molding method in which the stamper surface is first released when the mold is opened, and a related technique of this stamper surface preferential release molding method is disclosed in, for example, JP-A-1-306214. There is a gazette. In this type of mold, there is no particular distinction between the fixed mold and the movable mold. In the examples shown in FIGS. 16 and 17, the stamper is located on the movable side, but may be located on the fixed side. Absent. As an example in which a stamper is provided on the fixed side, for example, there is one described in JP-A-1-306214.

An optical disk substrate molded using such a conventional optical disk substrate molding die is shown in FIGS.
It is shown in FIG. An optical disk substrate 61 shown in the figure has an information surface 61a in which information pits 63 are formed in an information storage region 62, a mirror surface 61b on the back surface thereof, and a non-information storage region 64 on the inner and outer peripheral sides. And the outer diameter is φ80
mm ~ φ300mm, thickness t is 1.2mm ~ 1.5m
m is common. A recess 61C is transferred to the non-information storage area 64 on the center side of the information storage area 62 of the substrate 61 by the claw 5a of the inner peripheral stamper holder 5.

[0010]

Conventionally, a plastic substrate used for an optical disk substrate as described above has a thickness of about 1.2 to 1.5 mm, a diameter of about 80 to 300 mm, and is made of acrylic resin or polycarbonate. It is common to use a resin. However, with the miniaturization and thinning of products in the future, the optical disk substrate itself will become smaller and thinner (1.0
mm or less). In the above prior art, no consideration was given to molding this thin optical disk, and the following problems were encountered.

(1) It is difficult to make the height of the claw of the inner peripheral stamper holder for holding down the inner diameter side of the stamper 0.3 mm or less in terms of strength. 0.3-0.5 mm is common. In the prior art, the cavity thickness is reduced by the height of the claw. FIG. 20 shows this state. During molding, when the resin is injected, the flow of the resin is limited to a small extent at the claw portion. There is no problem if the thickness of the substrate is as thick as about 1.2 to 1.5 mm, but it is 1.0 mm or less, particularly 0.5 mm
In the following cases, if the height of the claw is 0.3 mm, the cavity thickness of the claw portion is 0.2 mm and the flow of the resin is deteriorated, causing optical distortion (birefringence), warpage of the substrate, and rotation during rotation. There has been a problem that mechanical characteristics of the optical disc substrate such as surface runout are deteriorated.

Further, in order to improve the flow of the resin, in the prior art, as shown in FIG. 21, there is an example in which a convex portion is formed on the opposite surface (mirror surface 61b) of the concave portion 61C. In this example, the flow of the resin is improved, but the thickness of the entire substrate is increased, which is disadvantageous for a thin optical disk. For example, in the case of a plate thickness of 0.5 mm, if a 0.3 mm convex portion is formed, the thickness of the entire substrate will be 0.8 mm. In addition, there is a problem that the mechanical characteristics of the optical disk substrate such as the warpage of the substrate and the runout during rotation deteriorate.

(2) In the case of a stamper surface preferential release mold (a mold of the present system is often used for the purpose of improving the transferability of minute irregularities which are information of the stamper), the adhesiveness is higher than that of the stamper surface. Since the molded substrate is left on the bad mirror surface side, the outer peripheral ring forming the outer diameter surface of the molded product is often on the mirror surface side. When the mold is released from the mirror surface, of the residual pressure in the cavity immediately before opening the mold,
If the pressure applied to the outer diameter surface of the molded product differs from place to place, or if the mold release resistance of the outer diameter surface of the molded article differs from place to place, the compressed air supplied from the air slit should be smooth and uniform. When the molded product is extruded by the ejector ring at the center because it does not spread, the mold release delay occurs, especially in places where the residual pressure is large or where the release resistance is large, and the molded product is deformed, causing warpage or rotation of the substrate. There is a problem that mechanical characteristics as an optical disk substrate are deteriorated such as surface runout.

(3) When the substrate is released from the mirror block after the mold is completely opened in the above (2), compressed air is blown out from an air slit provided near the center of the movable mold. Although the mechanical ejector rod protrudes and releases the mold, the ejector ring is located only at the center of the substrate, so that no force is applied to the substrate on average and the substrate warps, the surface oscillates during rotation, etc. There was a problem that the mechanical characteristics deteriorated.

(4) When the molded product is extruded by the compressed air supplied from the air slit and the ejector ring at the center, and the molded product is transferred to the molded product removal device, the movement of the ejector ring and the movement of the removal device are synchronized. It was not removed, and the difference in movement between the molded product take-out device and the ejector ring was absorbed by the spring of the take-out device. If the thickness of the substrate is as thick as about 1.2 to 1.5 mm, there is no particular problem because the substrate has rigidity, but when the thickness of the substrate is 1.0 mm or less, particularly 0.5 mm or less. Has low rigidity and loses the force of the mechanism of absorbing the difference between the ejector ring movement and the molded product take-out device such as the spring of the take-out device, deteriorating the mechanical characteristics of the optical disc substrate such as the warpage of the substrate and the runout during rotation There was a problem of doing.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. In particular, a thin optical disk substrate is not deformed sequentially from a fixed type and a movable type.
It is possible to manufacture an optical disk substrate with smooth mold release and no deterioration of mechanical characteristics such as substrate warpage and surface runout during rotation .
Molding die Unishi were optical disk substrate and a process for producing the same <br/>, it is an object thereof.

[0017]

The above object is achieved by the following. That is, the present invention provides a split type of a fixed type and a movable type.
In a molding die of an optical disc substrate composed of:
The fixed type is attached to the fixed type main body and the fixed type main body.
The center of the sprue bush that injects molten resin
Fixed mirror block,
A stamper on the lock and the information side of the stamper on the cavity side
And fixed on the inner and outer diameter sides
And an outer peripheral stamper holder, wherein the movable die is
The movable body is facing the information surface of the stamper.
It has a surface that forms the
A movable mirror configured to move in the opening and closing direction of the dynamic mold
Block, and the key attached to the movable body.
An outer peripheral ring forming an outer diameter surface of the cavity;
Opening of the movable mirror with respect to the movable mirror block and the movable mirror block.
An ejector member configured to move in the closing direction;
The movable mold is clamped to the fixed mold.
The spool bushing in the cavity formed
The molten resin is cast from the stamper and recorded on the information surface of the stamper.
The information pits are transferred to form an optical disc substrate,
When the movable mold is opened with respect to the fixed mold,
While holding the optical disk substrate in a movable mold,
And then the movable mirror block and
The ejector member is simultaneously moved with respect to the outer ring.
The movable mirror block and the eject
The outer diameter surface of the optical disc substrate held by the
Release from the ring, and then move the ejector member further.
The light held by the ejector member by moving
Release the disk substrate from the movable mirror block
It is characterized by having such a configuration. In addition, the present invention
Inner circumference stamper for fixed mold of optical disk molding die
At the solder, press the claw that presses the inner diameter side of the stamper
Formed so as not to protrude from the information side of the damper to the cavity side
It is characterized by having done.

The present invention also relates to the optical disk molding die.
The movable member of the movable mirror
The inner peripheral ejector ring installed on the inner periphery of the block
It is characterized by having done. Further, the present invention provides the optical
The ejector member in the movable mold of the molding die is
The inner and outer peripheries of the movable mirror block
It is characterized by comprising a peripheral and peripheral ejector ring
I do. The outer ejector ring is a movable mirror
The ring portion of the block corresponds.

Further , the present invention provides a fixed type main body,
A sprue that is attached to the body and injects molten resin
Fixed mirror block with a
And a stamper on the fixed type mirror block.
With the reporting surface on the cavity side and on the inner and outer diameter sides
It has an inner and outer stamper holder
Fixed type, movable type body, facing the information surface of the stamper
Said movable body having a surface forming a cavity by
It is configured to move in the movable opening and closing direction with respect to
Movable mirror block attached to the movable body
An outer peripheral ring forming an outer diameter surface of the cavity;
And the outer ring and the movable mirror block.
To move in the opening and closing direction of the movable mold.
Light comprising a movable member having a
Using a molding die for a disk substrate, the movable die is fixed
Into the cavity formed by clamping against
Casting molten resin from the spool bush
Transfers information pits recorded on the information surface of an optical disk
Form a substrate and open the movable mold with respect to the fixed mold
When holding the molded optical disk substrate in a movable mold
Release from the stamper with the movable mold
Mirror block and ejector member on the outer ring
The movable mirror
Optical disk substrate held by lock and ejector members
Release the outer diameter surface of the outer ring from the outer ring, and then
The ejector member by further moving the ejector member.
The optical disk substrate held by the member is moved to the movable mirror
An optical disc characterized by being manufactured by releasing from a lock.
This is a method for manufacturing a substrate.

The present invention further provides a molded optical disk.
The light is synchronized with the release of the disk substrate from the movable die and the timing.
Equipped with a molded substrate take-out device for taking out disk substrates
It is characterized by the following.

[0021]

The function of each of the above technical means is as follows. (1) In the conventional technique, the cavity thickness is reduced by the height of the stamper claw, and when the resin is injected at the time of molding when the thickness of the substrate is reduced, the flow of the resin is limited at the claw portion. Was to be done. Therefore, the thickness of the stamper is set to 0.5 mm to 1.5 mm, and the inner diameter of the stamper is tapered or stepped such that the diameter on the information surface side is larger than the diameter on the non-information surface side. Alternatively, if the inner peripheral stamper holder with the same tapered or stepped shape as the stepped shape is fixed to the mirror block, the stamper can be fixed without projecting the claw from the information side of the stamper to the cavity side, and the flow of resin can be reduced. There is no restriction. Therefore, the mechanical characteristics of the optical disk substrate, such as optical distortion (birefringence), substrate warpage, and surface runout during rotation, do not deteriorate.

(2) Conventionally, when the disk substrate is released from the mirror surface with the outer peripheral ring of the die, the pressure applied to the outer diameter surface of the molded product among the residual pressures in the cavity immediately before opening the mold differs depending on the location. Or because the mold release resistance of the outer diameter surface of the molded product differs depending on the location, even if the compressed air supplied from the air slit is blown out, it does not spread smoothly and evenly. When extruding, the mold release is delayed particularly at a place where the residual pressure is large or where the release resistance is large, and the molded product is deformed. On the other hand, in the mold of the present invention, since the outer diameter surface of the disk substrate is released from the entire mirror block in a state where the disk substrate is in close contact with the mirror surface, the die is not affected by the release resistance of the outer diameter surface. The outer diameter surface can be released. In this state, if the ejector ring is pushed out while blowing out the compressed air from the air slit, there is no difference in mold release resistance, and there is no occurrence of substrate warpage, surface runout during rotation, and the like.

(3) If the ejector ring and the outer peripheral ejector ring of the outer peripheral portion of the mirror block are simultaneously extruded, the molded product can be released from the mold while maintaining the flatness. Does not occur. Furthermore, if the moving speed of the mirror block can be variably controlled and the start of the movement is slowed down, the molding cycle can be shortened without causing substrate warpage or surface runout during rotation even if the subsequent speed is increased. . When the molded product is extruded with the compressed air supplied from the air slit and the ejector ring at the center and the molded product is delivered to the molded product removal device, the timing of the movement of the ejector ring is detected by the sensor, and at that timing, the removal device is operated. If the retreat is performed at the same speed as the extrusion speed of the molded product, no force is applied to the molded product, and the mechanical characteristics of the optical disc substrate such as the warpage of the substrate and the runout during rotation are not degraded.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.
This will be described with reference to FIG. First, an optical disk substrate molded using a molding die (details described later) according to the present invention will be described. Embodiment 1 FIG. 1 is a partially cutaway perspective view of an optical disc substrate according to an embodiment of the present invention, FIG. 2 is an enlarged view of a portion A in FIG. 1, and FIG. 3 uses the optical disc substrate of FIG. FIG. 3A is an explanatory view of an optical disk in card, FIG.
4B is a sectional view, FIG. 4 is an enlarged view of a portion B in FIG. 3B, FIG. 5 is an explanatory view of a laptop personal computer using the optical disc in card of FIG. 3, and FIG. 6 is information of FIG. It is a perspective view showing the structure of a processing part.

In FIG. 1 and FIG.
Has an information surface 51a in which information pits 53 are formed in the information storage area 52 and a mirror surface 51b on the back surface thereof. The outer diameter is φ50 mm and the thickness t is 0.5 mm. The optical disk substrate 51 has an accurate information pit 53
In addition to the transfer, the disk itself must be free of warpage and twist. The warpage is called a tilt and the twist is called a surface run-out, and is 0.05 mm or less and 0.01 mm or less, respectively.
This optical disk substrate 51 does not have the uneven portions as previously shown in FIGS. 19, 20, and 21, and the entire substrate has a thickness of 0.5 m.
m and the tilt which is a mechanical property of the optical disc substrate,
It is formed so as to sufficiently satisfy the requirements for surface runout.

Such an optical disk substrate 51 is rotatably housed in a case 102 (54 mm × 86 mm) having a transparent portion 101 as shown in FIG. FIG.
As shown in (1), since the optical disc substrate 51 has no concave and convex portions, the gap between the case 102 and the optical disc substrate 51 is 0.
1 mm, and the optical disk in card 103
The total thickness could be 1.3 mm.

FIG. 5 shows an application example of the optical disk in card of this embodiment. In recent years, laptop computers and other portable information processing apparatuses have been required to be more portable, and their thicknesses have to be reduced in order to reduce the size and weight. Further, the memory is required to have a larger capacity. Conventionally used memories include an IC card, a magnetic disk, and an optical disk. However, there is a problem in practical use in terms of capacity of the IC card and miniaturization of the optical disk.
By applying the ultra-thin optical disk substrate 51 according to the present embodiment, it was possible to achieve a small and lightweight memory size of 80 megabytes, which is about 80 times that of a floppy disk. A mold for molding an optical disk substrate having such a shape accuracy will be described below.

Embodiment 2 FIG. 7 is a longitudinal sectional view showing one embodiment of a mold for molding the optical disk substrate of FIG. 1, and FIG. 8 is an enlarged sectional view of a stamper mounting portion of FIG. The molding die shown in FIG. 7 includes a movable die 1 and a fixed die 2 which are a pair of die portions constituting a split die. The fixed mold 2 is provided with a fixed mirror block (fixed mirror block) 12 with respect to the fixed body .
A stamper 4 is mounted on the surface of the fixed mirror block 12, and the outer periphery of the stamper 4 is
The inner peripheral portion is attached to the fixed mirror block 12 by the inner peripheral stamper holder 5. A sprue bush 13 is arranged at the center of the fixed mirror block 12.

On the other hand, in the movable mold 1, a movable mirror block (movable mirror block) 6 is installed so as to be movable in the mold opening and closing direction with respect to the movable mold body. The outer peripheral ring 11 forming the outer diameter portion is fixed to the movable body . An ejector ring (inner ejector ring) 8 is provided on the inner peripheral side of the movable mirror block 6, a sleeve 17 is provided on the inner peripheral side thereof, a gate cut punch 14 is provided on the inner side thereof, and an ejector pin 15 is provided on a central portion thereof. Is provided. The ejector ring 8 is provided with a position sensor 18.
It is possible to detect the start time of the movement. The cavity 3 is formed by the stamper surface 4a, the movable mirror block 6, and the outer peripheral ring 11 of the molding die.

FIG. 8 is an enlarged sectional view showing a method of attaching the stamper 4 in the above molding die. In FIG.
The stamper 4 has a thickness of 0.6 mm, and the inner peripheral side has a taper shape with a taper angle of 45 ° such that the information side 4a of the stamper 4 is larger than the non-information side 4b. Further, the inner peripheral stamper holder 5 has the claw portion 5a having the same tapered shape (taper angle 45 °) as the inner peripheral portion of the stamper, the claw portion 5a has a height of 0.6 mm, and the fixed mirror block 12 Fixed. By adopting such a shape, the claw portion 5a does not become closer to the cavity than the information surface 4a of the stamper 4, and therefore the resin can be cast without impairing the flow of the resin.

Here, in the present embodiment, the thickness of the stamper 4 is 0.6 mm, but a similar mounting method can be applied within a range of 0.5 mm to 1.5 mm. Naturally the thinner is stamper 4
Is simple and advantageous from the viewpoint of temperature control of the information surface 4a, but the limit is about 0.5 mm in view of the fixing strength of the stamper 4. Also, as the outer diameter of the molded substrate increases, the mounting strength of the stamper 4 also needs to be increased. However, the manufacturing cost of the stamper 4 increases, and when the stamper 4 is thick, the manufacture of the stamper 4 becomes difficult. Generally, the stamper is made by nickel plating on a glass master. However, when the plating thickness is large, the stress strain when plating is increased, and the stamper comes off from the glass master. As a result of the experiment, φ
At 300 mm, the thickness was limited to 1.5 mm. Further, the angle of the taper can be appropriately set in the range of 20 ° to 70 ° depending on the relationship between the thickness of the stamper 4 and the strength of the claw portion 5a.

[Embodiment 3] FIG. 9 is an enlarged sectional view of a stamper mounting portion of an optical disk substrate molding die according to another embodiment of the present invention. The thickness of the stamper 4A in the embodiment of FIG.
5 mm. The inner peripheral side of the stamper 4A has a stepped shape such that its information side 4a is larger than the non-information side 4b. Also, the inner peripheral stamper holder 5A has its claw 5b with the same step as the inner peripheral part of the stamper 4A,
The height of the claw portion 5 b was made smaller than the step thickness of the circle on the information surface 4 a side, and was fixed to the fixed mirror block 12. With such a shape, the claw portion 5b does not become closer to the cavity than the information surface 4a of the stamper 4A, and the same effect as the embodiment of FIG. 8 can be obtained.

Embodiment 4 Still another embodiment of the present invention will be described with reference to FIG. 7 and FIGS.
FIG. 10 is a sectional view showing a movable mold immediately after opening a mold of an optical disk substrate forming mold according to still another embodiment of the present invention.
1 is a cross-sectional view of a movable mold showing a release state due to protrusion of a movable mirror block, FIG. 12 is a cross-sectional view of a movable mold showing a release state due to protrusion of an ejector ring, and FIG.
FIG. 4 is a cross-sectional view of the movable mold showing a released state without depending on the protrusion of the movable mirror block. In each drawing, the same reference numerals as those in FIG. 7 indicate the same parts.

In FIG. 7, the fixed die 2 of the molding die is mounted on a fixed die plate of an injection molding machine (not shown), and the movable die 1 is mounted on the movable die plate. And solidified by casting into the cavity 3. When opening the mold, the solidified molded substrate blows out compressed air from a gap between the sprue bush 13 and the inner peripheral stamper holder 5 and opens the mold while vacuum-suctioning from a gap between the sleeve 17 and the ejector ring 8. Thereby, the molded substrate 50 molded in the cavity 3 is
The molded substrate is fixed to the fixed mold 2 by the compressed air blown out from the fixed mold 2, the vacuum suction force of the movable mold 1, the mold release resistance of the outer diameter surface of the molded substrate of the outer peripheral ring 11 installed on the movable mold 1, and the like. And the mold is opened while remaining and held on the movable mold 1 side.

The movable mold 1 and the molded substrate 50 immediately after the mold is opened
FIG. 10 shows this state. In this state, the movable mirror block 6, the ejector ring 8, the sleeve 17, the gate cut punch 14, and the ejector pin 15 are simultaneously moved in the fixed mold direction. The moving distance is at least the thickness of the molded substrate 50 or more. In this embodiment, the plate thickness is 0.5 mm,
The moving distance was 1.5 mm in consideration of other plate thicknesses. The method of moving is not particularly specified, but can be sufficiently realized by applying the conventional technology. For example, there are means for providing a hydraulic cylinder in the movable mold 1 for driving, and providing a drive source in the injection molding machine to drive the movable mold 1. The driving source is a hydraulic pressure, an electric motor, or the like.

The movable mold 1 and the molded substrate 50 after the above movement
FIG. 11 shows this state. By doing so, the outer diameter surface 50 a of the molded substrate 50 can be released from the outer peripheral ring 11 without applying stress to the molded substrate 50. next,
The ejector ring 8 and the ejector pin 15 are simultaneously moved in the fixed direction without moving the movable mirror block 6. At this time, it is more preferable to perform the process while blowing compressed air from between the sleeve 17 and the ejector ring 8.

The movable mold 1 and the molded substrate 50 after the movement
12 is shown in FIG. By simultaneously moving the ejector ring 8 and the ejector pin 15, the molding substrate 50
Is released from the movable mirror block 6. If the mold is released by such a method, the mirror surface 50b
The adhesion between the movable side mirror block 6 and the movable side mirror block 6 is not so large, the mold can be released without deformation of the molded substrate 50, and an optical disk substrate that sufficiently satisfies the requirements of tilt and surface deflection can be formed.

FIG. 13 shows a release state when the ejector ring 8 and the ejector pin 15 are simultaneously moved without moving the movable side mirror block 6 for an experiment. When the ejector ring 8 and the ejector pin 15 are moved without moving the movable mirror block 6, the residual pressure in the cavity immediately before the mold opening is reduced.
The pressure applied to the outer surface of the molded product varies depending on the location, or the release resistance of the outer surface of the molded product varies depending on the location. Deformation occurred, and the mechanical characteristics of the optical disk substrate, such as substrate warpage and rotation during rotation, deteriorated.

[Embodiment 5] FIG. 14 is a cross-sectional view showing a mold release state after opening a mold of an optical disk substrate molding die according to still another embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 7 indicate the same parts. In the embodiment of FIG. 14, the movable-side mirror block 6A is divided into an inner-peripheral-side block 6a into which the ejector ring 8 is to be inserted and a ring portion 6b to be in contact with the outer peripheral portion 50d of the molded disk. . The outer ring 6b is moved in the mold opening / closing direction by synchronizing with the ejector ring 8 in the cavity inner periphery. When the molded substrate 50 is released from the mold, the ring 6b and the ejector ring 8 are synchronized and moved in the mold opening / closing direction simultaneously. Folded molded substrate 5
0 was taken out.

According to the embodiment shown in FIG.
Since the inner peripheral portion 50c and the outer peripheral portion 50d are simultaneously released from the mold, the mold can be released with less deformation than in the previous embodiment. However, in this case, a streak-like mark due to the splitting of the movable-side mirror block 6A is formed on the molded substrate 50.
Is left on the mirror surface 50b, so that the position of the split mold is
It is desirable to set the range to exclude the 0 information area.

Embodiment 6 Next, another embodiment will be described with reference to FIGS. FIG. 15 is a cross-sectional view showing a mold release state after opening the mold of the optical disk substrate molding die according to still another embodiment of the present invention. In FIG. 7, after casting the resin, the gate cut punch 14 may be moved in the fixed mold 2 direction to make a center hole 50e in the molded substrate 50 in some cases. The state of the movable mold when this center hole is drilled is shown in FIG.
FIG. 15 shows a state in which the ejector pin 15 is moved for releasing after the mold is opened. When the center hole 50e is opened, the ejector pin 15 is moved before the ejector ring 8 in order to separate the sprue portion 50f and the disk portion 50g when releasing the mold.

Next, the ejector ring 8 is moved. Conventionally, the ejector operation from the injection molding machine side is one, so that the ejector pin 15 and the ejector ring 8 are provided with a stroke delay by a mold structure. I was moving. On the other hand, the timing of the molded substrate unloading device (not shown) is set at the start of the ejection, that is, at the start of the movement of the ejector pin 15, so that it is difficult to take the timing with the actual release of the disk portion 50g. .
Therefore, the force of the substrate take-out device may be applied to the disk portion 50g to deform the disk portion. In view of this, a sensor 18 for detecting the start of movement is provided in the ejector ring 8 and the molded substrate unloading device is moved in synchronization with this timing. The mold release operation was performed by adjusting the moving speed of the molded substrate unloading device to the ejector speed of the mold. According to the embodiment of FIG. 15, the force of the molded substrate removal device is not applied to the disk portion 50g,
It is possible to take out the disk portion 50g without deformation.

According to each of the above embodiments, the very thin type (t
= 0.3-0.5 mm) and a thickness of 1.
Applicable to 3 mm optical disk in card. And
If the optical disk in card is applied, a very small and large-capacity (80 megabytes) information processing device can be realized. In addition, this optical disk substrate does not have a concave portion on the information surface side, that is, there is no thin portion in the cavity portion, so that the resin flow is good, and optical distortion (birefringence), substrate warpage, surface runout during rotation, etc. A substrate having excellent mechanical properties can be obtained.

Further, since the outer diameter portion of the substrate can be released from the entire mirror block and the speed at the initial stage of the release can be reduced, a force due to the unbalance of the release force of the outer diameter portion of the substrate is not applied to the molded substrate, and the optical substrate is not optically affected. An optical disc substrate having excellent mechanical characteristics such as mechanical distortion (birefringence), substrate warpage, and surface runout during rotation can be obtained. Furthermore, when the disk part is released, the inner and outer peripheral sides of the disk part can be released at the same time in a well-balanced manner. An excellent optical disk substrate can be obtained. Furthermore, at the start of the ejector, the speed can be synchronized with the molded substrate unloading device, so that the molded substrate is not subjected to excessive force from the unloading device, and optical distortion (birefringence), substrate warpage, and rotation. An optical disc substrate having excellent mechanical properties such as surface runout can be obtained.

As a result of molding an optical disk substrate having a diameter of 50 mm and a thickness of 0.5 mm with the material polycarbonate using the optical disk substrate molding dies according to the above-described embodiments, the birefringence of 50 mm was obtained.
nm or less, tilt 0.01 nm or less, surface runout 0.01 n
m or less could be realized.

[0046]

As described above in detail, according to the present invention, particularly for a thin optical disk substrate, a fixed type optical disk substrate is used.
Smooth mold release without successive deformation from movable and movable molds
By doing so, it is possible to manufacture an optical disk substrate without deterioration of mechanical characteristics such as substrate warpage and surface runout during rotation.
It has a clear effect .

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of an optical disc substrate according to one embodiment of the present invention.

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is an explanatory diagram of an optical disk in card using the optical disk substrate of FIG. 1;

FIG. 4 is an enlarged view of a portion B in FIG. 3;

FIG. 5 is an explanatory diagram of a laptop personal computer using the optical disc in card of FIG. 3;

FIG. 6 is a perspective view illustrating a structure of an information processing unit in FIG. 5;

FIG. 7 is a longitudinal sectional view showing one embodiment of a mold for molding the optical disk substrate of FIG. 1;

FIG. 8 is an enlarged cross-sectional view of the stamper mounting portion of FIG.

FIG. 9 is an enlarged sectional view of a stamper mounting portion of an optical disk substrate molding die according to another embodiment of the present invention.

FIG. 10 is a cross-sectional view showing a movable mold immediately after opening a mold of an optical disk substrate forming mold according to still another embodiment of the present invention.

FIG. 11 is a cross-sectional view of a movable mold showing a released state due to protrusion of a movable mirror block.

FIG. 12 is a cross-sectional view of a movable mold showing a release state due to ejection of an ejector ring.

FIG. 13 is a cross-sectional view of the movable mold showing a released state without depending on the protrusion of the movable mirror block.

FIG. 14 is a cross-sectional view showing a mold release state after opening of an optical disk substrate molding die according to still another embodiment of the present invention.

FIG. 15 is a cross-sectional view showing a mold release state after opening of an optical disk substrate molding die according to still another embodiment of the present invention.

FIG. 16 is a sectional view showing an example of a molding die for molding a conventional optical disk substrate.

FIG. 17 is a sectional view showing another example of a molding die for molding a conventional optical disk substrate.

FIG. 18 is a partially cutaway perspective view showing a conventional optical disc substrate.

19 is a partially enlarged sectional view of a portion C in FIG. 18;

FIG. 20 is a cross-sectional view when a conventional optical disk substrate is assumed to have a small thickness.

FIG. 21 is a cross-sectional view of another example when the thickness of a conventional optical disk substrate is assumed to be thin.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Movable mold 2 Fixed mold 3 Cavity 4, 4A stamper 5, 5A Inner peripheral stamper holder 5a Claw part 6, 6A Movable mirror block 6b Ring 7 Outer peripheral stamper holder 8 Ejector ring 11 Outer peripheral ring 12 Fixed mirror block 13 Sprue bush 14 Gate cut Punch 15 Ejector pin 17 Sleeve 18 Position sensor 50 Molded substrate 50a Outer diameter surface 51 Optical disk substrate 52 Information storage area 53 Information pit 51a Information surface 51b Mirror surface

──────────────────────────────────────────────────続 き Continued on the front page (72) Keiji Takasu, Inventor 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture, Hitachi, Ltd. Production Engineering Laboratory Co., Ltd. (56) References JP-A-2-110840 (JP, A) Hei 2-243317 (JP, A) Japanese Utility Model Showa Sho 62-80620 (JP, U) Japanese Utility Model Utility Model Hei 3-50416 (JP, U) Japanese Patent Publication No. 3-75333 (JP, B2) (58) Fields surveyed (Int) .Cl. ⁷ , DB name) G11B 7/26 B29C 45/26-45/44

Claims (12)

(57) [Claims] An optical device comprising a split type of a fixed type and a movable type.
In a molding die for a disk substrate , the fixed mold is attached to the fixed mold body and the fixed mold body.
Centered on a sprue bush that injects molten resin
Fixed mirror block arranged in a section, and the fixed mirror
Stamper on block, cavity on the information side of the stamper
Side and fix the inner and outer diameter sides.
And the outer peripheral stamper holder, the movable die, a movable die body, the information surface of the stamper and
A movable mold having a surface facing the cavity to form the cavity;
It is configured to move in the opening and closing direction of the movable type with respect to the main body.
Movable mirror block attached to the movable body
Peripheral ring forming an outer diameter surface of the cavity
And the outer peripheral ring and the movable mirror block.
To move in the opening and closing direction of the movable mold.
And a movable member is formed by clamping the movable mold to a fixed mold.
Cast molten resin from the spool bush into the cavity
The information pit recorded on the information surface of the stamper
Transfer to form an optical disk substrate, and move the movable mold to a fixed mold
When the mold is opened with respect to the molded optical disc substrate
Is released from the stamper while holding the movable mold.
And then the movable mirror block and the ejector section
By simultaneously moving the material with respect to the outer ring,
Held on the movable mirror block and ejector member
The outer diameter surface of the separated optical disc substrate is separated from the outer ring.
Mold, and then move the ejector member further.
Therefore, the optical disk substrate held by the ejector member
Is configured to be released from the movable mirror block.
A molding die for an optical disc substrate . 2. An inner peripheral stamper holder in the fixed type.
The claw that presses the inner diameter side of the stamper
It is formed so that it does not protrude from the information surface to the cavity side.
2. A molding metal for an optical disk substrate according to claim 1, wherein
Type . 3. An ejector member of the movable mold is provided at a front end.
An inner peripheral edge set on the inner periphery of the movable mirror block
2. The method as claimed in claim 1, wherein
2. A molding die for an optical disc substrate according to 2 . 4. An ejector member in the movable mold, wherein :
Installed on the inner and outer circumferences of the movable mirror block
Characterized by inner and outer ejector rings
3. A molding metal for an optical disk substrate according to claim 1, wherein
Type . 5. The movable die according to claim 1 , further comprising:
Inside the movable mirror block,
Drill the center of the held optical disk substrate
Holds gate cut punch and sprue at the center
And an ejector pin to be provided.
5. A molding die for an optical disk substrate according to 3 or 4 . 6. The optical disk substrate according to claim 1, further comprising :
The molding is performed at the same time as the release from the movable mold.
To take out the molded optical disc substrate
The optical disk according to claim 1, wherein the optical disk is provided.
Forming die for disk substrate . 7. A fixed body, and attached to the fixed body.
The center of the sprue bush that injects molten resin
Fixed mirror block and fixed mirror
-A stamper is placed on the block and the information side of the stamper is
Inner side and outer diameter side
And fixed type with outer and outer stamper holders.
The movable body, the cavity facing the information surface of the stamper
Having a surface forming a movable body,
Movable mirror configured to move in the opening and closing directions
The lock is attached to the movable body and the cavity
Outer peripheral ring forming an outer diameter surface of an outer ring, and the outer peripheral ring
And opening and closing of the movable mirror block with respect to the movable mirror block
An ejector member configured to move in the
Optical disk substrate consisting of a movable die
Using a mold, the movable mold is formed by clamping the movable mold to a fixed mold.
The molten resin cast from the spool bush in the cavity
The information pit recorded on the information surface of the stamper
Transfer to form an optical disk substrate, and move the movable mold to a fixed mold
When the mold is opened with respect to the molded optical disc substrate
Is released from the stamper while holding the movable mold.
And then the movable mirror block and the ejector section
By simultaneously moving the material with respect to the outer ring,
Held on the movable mirror block and ejector member
The outer diameter surface of the separated optical disc substrate is separated from the outer ring.
Mold, and then move the ejector member further.
Therefore, the optical disk substrate held by the ejector member
Is manufactured by releasing from the movable mirror block.
A method for manufacturing an optical disk substrate, comprising: 8. An inner peripheral stamper holder in the fixed type.
The claw that presses the inner diameter side of the stamper
It is formed so that it does not protrude from the information surface to the cavity side.
Eliminates recesses on the inner circumference of the information surface of the manufactured optical disc substrate
8. An optical disk substrate according to claim 7, wherein:
Construction method . 9. An ejector member in the movable mold, wherein
An inner peripheral edge set on the inner periphery of the movable mirror block
And the inner peripheral ejector ring
The optical disk substrate is released from the mold.
Or a method for manufacturing an optical disk substrate according to item 8 . 10. An ejector member in the movable mold,
Installed on the inner and outer circumferences of the movable mirror block
And inner and outer ejector rings.
Separate the optical disk substrate using the
9. The optical device according to claim 7, wherein the optical device is shaped.
Manufacturing method of disk substrate . 11. The movable mold is opened with respect to a fixed mold.
At the time, fixed to the optical disk substrate molded from the fixed mold
Blow out compressed air from the mold, and vacuum the movable mold
An optical disc according to any one of claims 7 to 10, wherein
Manufacturing method of disk substrate . 12. The movable mirror blower according to claim 12, wherein said ejector member is a movable mirror blower.
When moving further with respect to the optical disc substrate
Claims characterized by blowing compressed air from a movable mold
Item 10. The method for manufacturing an optical disk substrate according to any one of Items 7 to 10.
Law .