JPH02128808A - Die for molding optical disk board - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a disc-shaped record carrier (hereinafter referred to as
It is simply called an optical disk substrate. ) is related to a mold for molding.

[Prior Art] Conventionally, in a mold for molding an optical disk substrate, as shown in FIGS. 3 and 4, an inner stamper (not shown) is mounted on one mirror plate 2 (the movable mirror plate in the figure) on the inner diameter side of the stamper 5. The outer diameter side is fixed with an outer stamper presser 3°, and the one mirror plate 2 and the other mirror plate l facing the mirror plate 2 are fixed with an outer stamper presser 3 or the outer stamper presser. A cavity 6 can be formed by clamping the mold through a cavity ring 4° located inside the stamper holder 3′. Therefore, the outer diameter side surface of the molded product is formed by the inner diameter side surface of the outer stamper holder 3'' or the inner diameter side surface of the cavity ring 4''.

Also, connect the other mirror plate 1 and outer stamper holder 3'' (
Alternatively, air slits 8.9 are provided between the cavity ring 4'') and between the outer stamper holder 3'' (or cavity ring 4'') and the stamper 5, respectively. Therefore, as the molten resin is injected, the air inside the cavity can be exhausted through the air slits 8.9.

[Problem to be solved by the invention]

However, since the inner surface of the outer stamper holder 3' (or cavity ring 4') and the mirror surface of the mirror plate 1.2 intersect at right angles, and the air slit 8.9 is provided at the intersection, When pressurization is performed after the injection of the molten resin is completed, the pushing force of the molten resin against the air slits 8.9 is large, and the molten resin flows into the air slits, which tends to cause cracks. In particular, since the stamper 5 is usually finished by polishing after electroforming nickel, it is difficult to control the wall thickness, and it is extremely difficult to keep the air slit 8 constant for each stamper. It was easy for the slits 8 to form burrs, and when burrs were formed, there was a high risk of damaging the stamper 5.

Therefore, in order to make it difficult for air slits 8 to form on the stamper 5 side, a cavity ring 4 as shown in FIG.
It is also known that the inner surface of the cavity ring 4° is formed so that its diameter decreases toward the stamper 5 and intersects the stamper 5 at an obtuse angle. Since it intersects with the mirror surface at an acute angle, the pushing force of the molten resin against the air slit 9 on the side opposite to the stamper 5 becomes even greater, making it even more likely that pars will occur on the side opposite to the stamper 5.

In addition, the generated paris creates resistance when the molded product is opened and released after cooling, causing the outer peripheral edge of the molded product to warp and deform as it shakes during rotation, deteriorating the required mechanical properties.

[Object of the Invention] The present invention was made to solve the above problems, and in order to prevent mechanical deformation at the outer diameter end of the molded product,
The purpose is to prevent the occurrence of paris and to make it easy to release from the mold.

[Means to solve the problem]

The mold for molding an optical disk substrate of the present invention has the inner diameter side of the stamper fixed to the movable side (or fixed side) mirror plate with an inner stamper holder, and the outer diameter side fixed with an outer stamper holder, and the movable side ( (or fixed side) mirror plate and the fixed side (or movable side) mirror plate facing the mirror plate when clamping the mold,
In a mold for molding an optical disk substrate, which is provided to be able to form a cavity, the mirror plate on the fixed side (or movable side) is capable of butting against an outer stamper holder when the mold is clamped, and has a shape that allows the molded product to have an outer diameter of the molded product together with the stamper holder. A cavity ring capable of forming a side surface is attached, and the mirror surface of the fixed side (or movable side) mirror plate and the mirror surface of the fixed side (or movable side)
A rising surface that intersects at an edge angle greater than 90 degrees is provided, and a claw portion is provided on the stamper side portion of the inner surface of the outer stamper holder to form an inner surface whose diameter decreases toward the stamper and intersects at an edge angle greater than 90 degrees. In addition, air slits are provided between the fixed side (or movable side) mirror plate and the cavity ring, between the outer stamper holder and the stamper, and between the cavity ring and the outer stamper holder during mold clamping. The configuration achieves the above object.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In the figure, 1 is a fixed side mirror plate attached to a fixed platen, 2 is a movable side mirror plate attached to a movable platen, and the mirror plate 2
are disposed opposite to the mirror plate 1 so as to be movable back and forth by a mold clamping device.

Reference numeral 3 designates an annular outer stamper holder that is attached concentrically to the outer periphery of the movable side mirror plate 2; 4 is a cavity ring that is attached concentrically to the outer periphery of the fixed side mirror plate 1;
The movable mirror plate 2 and the movable mirror plate 2 are disposed facing each other so that they can be butted against each other when the mold is clamped, and can form the outer diameter side surface of the molded product.

Reference numeral 5 denotes a duplication stamper having uneven grooves according to recording information, and its outer diameter part is fixed by an outer stamper holder 3, and its inner diameter part is fixed by an inner stamper holder (not shown), so that the mirror surface 2a of the movable mirror plate 2 is fixed. is installed on.

Reference numeral 6 denotes a cavity facing the stamper 5, which is formed when the fixed side mirror plate 1 and the movable side mirror plate 2 are clamped together via the outer stamper holder 3 and the cavity ring 4.

The stamper 5 side part of the inner surface 3a of the outer stamper holder 3 has a diameter that decreases toward the stamper 5 and has a diameter of 90°.
A claw portion 7 is provided that forms a tapered surface 3b that intersects at a larger edge angle (in the embodiment, a tapered surface that is a zero surface of 45° in the shape of a molded product).

If the tip of the claw portion 7 is difficult to machine, forming a straight portion 7a of 0.2 [[un or less] at the tip portion of the claw portion 7 will have the same effect, as shown in FIG. 2, for example.

Also, the anti-stamper 5 on the inner surface 4a of the cavity ring 4
The side portion has a tapered surface 4b whose diameter decreases as it goes toward the side opposite to the stamper 5 (in the example, the shape of the molded product is 45°).
) and the mirror surface 1a of the fixed side mirror plate 1.
and a rising surface 4c (in the embodiment flush with the mirror surface 1a) intersecting with each other at an edge angle greater than 90°. It should be noted that there is no problem even if there is a step between the rising surface 4c of the cavity ring 4 and the mirror surface la of the fixed side mirror plate 1 due to the respective processing.

Reference numeral 8 denotes an air slit in the five stampers, which is provided between the outer stamper holder 3 and the stamper 5 so as to open at the tip end side of the claw portion 7.

9 is the air slit of the 5 anti-stamper cases, and the fixed side mirror plate 1
The cavity ring 4 is provided between the fixed side mirror plate 1 and the cavity ring 4 so as to be open at a plane portion consisting of the mirror surface 1a and the rising surface 9.

10 is an air slit provided on the cavity dividing surface,
It is provided between the outer stamper holder 3 and the cavity ring 4 so as to open at a surface that forms the outer diameter side surface of the molded product.

In addition, in this embodiment, the inner surface 3a of the outer stamper holder 3
A tapered surface 3b is formed between the stampers 5, and a tapered surface 4b is formed on the side opposite to the stamper of the inner surface 4a of the cavity ring 4.
Although an example in which a surface is formed has been described, as long as the edge angle can be prevented from being 90°, it does not have to be a 0-face, and may be, for example, an R-face.

[Function] During molding, the movable mirror plate 2 is advanced with respect to the fixed mirror plate 1 by the mold clamping device, the outer stamper holder 3 and the cavity ring 4 are butted against each other, and the movable mirror plate 2 is further advanced. When the stamper holder 3 and the cavity ring 4 are pressed against each other, the fixed side mirror plate 1 is removed.
The movable mirror plate 2 is clamped, and a cavity 6 is formed. Next, molten resin is injected into the cavity 6 by a plasticizing device (not shown), and the air slit 8.9 is injected into the cavity 6.
After the air in the cavity 6 is discharged by , IO, pressure holding and cooling are performed.

By the way, the air slit 8 on the stamper 5 side has an edge angle of 90
The air slit 9 on the side opposite to the stamper 5 is opened between the larger stamper 5 surface and the tapered surface 3b of the outer stamper holder 3, and the air slit 9 on the side opposite to the stamper 5 is formed on the mirror surface 1 of the fixed side mirror plate 1 with a ridge angle larger than 90°.
It opens between a and the rising surface 40 of the cavity ring 4,
In addition, since the air slit 10 provided in the cavity dividing surface opens between the inner surface 3a of the outer stamper holder 3 and the inner surface 4a of the cavity ring 4, the edge angle of which is larger than 90°, pressurization is performed after the injection of the molten resin is completed. Even if the molten resin is pushed into the air slits 8.9.10, the force of pushing the molten resin into the air slits 8, 9, and 10 is small, and the molten resin will not flow into any of the air slits and cause any cracks.

Further, after molding, contrary to the above, the movable side mirror plate 2 is moved back to perform mold release, but the cavity dividing surface is provided on the outer diameter side of the molded product, and the movable side mirror plate 2 is removed from the mold. The cavity ring 4 provided in 2 is released from the molded product, and
The molded product is released from the outer stamper holder 3 provided on the fixed side mirror plate 1 by ejection by an ejector mechanism (not shown), and the mold is removed to both sides of the molded product, so that the mold release resistance is significantly reduced.

〔Effect of the invention〕

As described above, in the present invention, the cavity dividing surface is provided at an arbitrary position on the outer diameter side surface of the molded product, so that the mold release resistance can be significantly reduced. No deformation occurs.

Also, between the outer stamper holder provided on the movable side (or fixed side) mirror plate and the molding surface of the stamper, and between the fixed side (or movable side) mirror plate facing the movable side (or fixed side) mirror plate and the mirror plate. The molding surfaces of the cavity ring provided in the above and the molding surfaces of the cavity ring on the cavity dividing surface and the outer stamper holder all intersect at obtuse angles, and a slit that opens at the intersection is provided to complete the injection of the molten resin. Since the pushing force of the molten resin against the air slit when post-pressurization is performed can be reduced, it is possible to reliably prevent the molten resin from flowing into the air slit and causing flakes.

Therefore, according to the present invention, it is possible to improve mold releasability and molding quality, and also to eliminate accidents that damage the stamper.

[Brief Description of the Drawings] Fig. 1 is a sectional view showing one embodiment of the present invention, and Fig. 2 is a sectional view showing an embodiment of the present invention.
Partially modified views of the figure, FIGS. 3, 4, and 5 are sectional views showing conventional examples. 1... Fixed side mirror plate, 2... Movable side mirror plate, 3... Outer stamper holder, 3a...
...inner surface, 3b...tapered surface, 4...
...Cavity ring, 4a...Inner surface, 4
b...Tapered surface, 4c...Rising surface, 5...Stamper, 6...Cavity, 7...Claw portion, 8. 9.10...Air slit.

Claims (1)

[Claims] (1) Fix the inner diameter side of the stamper to the movable side (or fixed side) mirror plate with an inner stamper holder, and fix the outer diameter side with an outer stamper holder, and connect the stamper with the movable side (or fixed side) mirror plate. , the fixed side (or movable side) facing the mirror plate
In a mold for molding an optical disk substrate in which a mirror plate is provided to form a cavity when the mold is clamped, the fixed side (or movable side) mirror plate can be butted against an outer stamper holder when the mold is clamped, and A cavity ring capable of forming the outer diameter side of the molded product is attached together with the stamper holder, and a cavity ring is attached to the inner side of the ring on the side opposite to the stamper at an angle greater than 90° with the mirror surface of the fixed side (or movable side) mirror plate. A raised surface that intersects is provided, and a claw portion is provided on the stamper side portion of the inner surface of the outer stamper holder to form an inner surface whose diameter decreases toward the stamper and intersects at an edge angle greater than 90 degrees, and a fixed side (or movable side) A mold for molding an optical disk substrate, characterized in that air slits are provided between a mirror plate and a cavity ring, between an outer stamper holder and a stamper, and between a cavity ring and an outer stamper holder during mold clamping.