JP2003170473A - Disc base plate mold and disc base plate molded by the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that the release of a disc base plate 15b from a first mirror plate 4 is difficult due to the low roughness of the surface of the mirror plate so that the base plate 15b is retained in a fixed mold 2 or a cloud appears on the surface of the base plate 15b due to the partial release, and when several tens to hundred of CD-Rs are stacked and sold, with the signal surface of the disc 16 facing down, that is the printed surface is disposed upside, and hence when a customer grasps the disc, the disc is hardly engaged with fingers so that the removal of the disc is very difficult. <P>SOLUTION: The disc base plate mold comprises a sectional trapezoidal first mirror plate provided on one of a movable mold and a fixed mold, a stamper mounted on the second mirror plate provided on the other of the movable mold and the fixed mold and a stamper retainer for holding the stamper in such a manner that the first mirror plate invades into the recess of the stamper retainer to form a cavity. The cavity is formed so that the end face of the stamper retainer has a larger diameter at the stamper side and a smaller diameter at the first mirror plate side. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding die for a disc substrate used for an optical disc, such as a compact disc or a mini disc, where information is recorded, reproduced or erased by using light. The present invention relates to a disk substrate molded with the mold.

[0002]

2. Description of the Related Art A part of a conventional disk substrate mold is shown in FIG. The disk substrate mold comprises a movable mold 1b and a fixed mold 2, and more specifically, a first mirror surface plate 4 having a trapezoidal cross section fixed to a mounting plate 3 of the fixed mold 2 and a movable frame 6 of the movable mold 1b. The second mirror surface plate 7 fixed to the second mirror surface plate 7, the stamper 8 mounted on the second mirror surface plate 7, and the stamper retainer 13b fixed to the movable frame 6 and holding the stamper on the second mirror surface plate 7.
The cavity 9b is a space surrounded by the cavity surface 14b of the first mirror surface plate 4, the stamper 8 and the stamper retainer 13b, and the first mirror surface plate 4 has an annular stamper retainer 13b.
It is formed by penetrating into the concave portion 13c which is the inner peripheral surface of the. The cavity end surface 14b has the same slope angle as that of the inner peripheral surface, and the inner peripheral surface faces the slope of the trapezoidal cross section of the first mirror surface plate 4 with a minute space therebetween. On the disk substrate 15b formed by the die having the above-described structure, the minute projections formed on the stamper 8 are transferred as pits to the signal surface 16 on the stamper 8 side. Disk substrate 15 after molding
A metal thin film is vapor-deposited on the signal surface 16 of b, and after forming a protective film, printing and label application are performed as necessary to complete a disk.

The disk substrate 15 in the above conventional mold.
The molding of b is performed as follows. After the molten resin is injected and filled into the cavity 9b and it is cooled and solidified, the movable mold 1b
When the mold is separated from the fixed mold 2 and the mold is opened, the disk substrate 15b is moved by the movable mold 1 by the adhesive force to the stamper 8 or the like.
The reading surface 17, which is the surface of the disk substrate 15b on the first mirror plate 4 side, moves to the take-out position of the disk substrate 15b together with b, but the surface roughness of the first mirror plate 4 is low. It may be easily attached to the mirror plate 4, and the disk substrate 15b may remain on the fixed mold 2. Also,
Even if the disk substrate 15b does not remain on the fixed mold 2,
The disk substrate 15b is partially released.
Stain called cloud, and defective appearance of haze appear on the surface of.

Further, in recent disc stores, tens to hundreds of discs, such as CD-Rs, are inserted into a spindle and stacked for sale. In this case, the discs are stacked with the signal side 16 or print side facing upwards, in order to enhance the discrimination effect. Therefore,
As is apparent from the above, the end surface of the disk is widened downward, and it is difficult for the customer to get the disk and it is very difficult to remove it.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems in the prior art. The problem to be solved is to make the corners of the signal surface of the disk substrate have an acute angle. It is an object of the present invention to provide a mold having a novel structure in which a cavity end surface which is a cavity forming surface of a stamper retainer of the mold is widened toward the stamper.

[0006]

To this end, the claims of the present invention are directed to a first mirror surface plate having a trapezoidal cross section provided on one of a movable mold and a fixed mold, and the other of the movable mold and the fixed mold. A disk substrate metal having a cavity formed by including a stamper mounted on a second mirror surface plate provided in the above and a stamper retainer holding the stamper, wherein the first mirror surface plate penetrates into a recess of the stamper retainer. In the mold, the cavity end surface of the stamper retainer is formed such that the diameter is large on the stamper side and small on the first mirror surface plate side. Further, in the disk substrate molded in the cavity of the mold, the angle formed by the vertical line at the corner of the signal surface and the end surface is 7
It was set to be 14 to 14 degrees.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view of a main part of a mold of the present invention. FIG. 2 is a cross-sectional view of both ends of the disk substrate of the present invention molded by the mold of FIG. FIG. 3 is a sectional view of a main part of a conventional mold. FIG. 4 is a cross-sectional view of both ends of a conventional disk substrate formed by the mold of FIG. In the drawings, the same reference numerals indicate the same members.

The disk substrate mold shown in FIG. 1 comprises a movable mold 1a and a fixed mold 2. More specifically, the first mirror surface plate 4 having a trapezoidal cross section fixed to a mounting plate 3 of the fixed mold 2 and the movable mold. A second mirror surface plate 7 fixed to the movable frame 6 of the mold 1a, a stamper 8 mounted on the second mirror surface plate 7, and a stamper retainer fixed to the movable frame 6 and holding the stamper on the second mirror surface plate 7. Thirteen
comprising a. The disk substrate mold of FIG. 1 only shows the main part, and as a part not shown, the fixed mold 2 has a sprue bush for introducing the molten resin from the injection device into the cavity 9a and a central opening in the disk substrate. The movable die 1a has a mesh cutter or the like, and the movable mold 1a has a center opening cooperating with the mesh cutter to punch a hole.
Although it has an ejector or the like for projecting a from the movable mold 1a, the description thereof is omitted because it is known. Cavity 9a
Is the first mirror plate 4, stamper 8 and stamper retainer 13.
It is a space surrounded by the cavity end surface 14a of a, and the first mirror surface plate 4 is formed by penetrating into the concave portion 13c which is the inner peripheral surface of the annular stamper retainer 13a. At this time, the outer peripheral end surface of the movable frame 6 is positioned and abutted against the fixed frame 5, and the movable mold 1a
And the fixed mold 2 are attached respectively, and both are clamped by a mold clamping device (not shown) capable of opening and closing the mold and clamping.
Therefore, the recess 13c does not contact the slope of the trapezoidal cross section of the first mirror surface plate 4 but faces each other with a minute space therebetween. The minute space communicates with the air discharge passage 10, and when the molten resin is filled in the cavity 9a, the molten resin is blocked and the cavity 9a is blocked.
It has a gap that allows the internal air and gas to escape to the atmosphere.

On the surface of the second mirror surface plate 7 facing the first mirror surface plate 4, a stamper 8 having desired information projected as minute projections is placed, and the information of the stamper 8 is projected. The back surface of the outer peripheral portion is not in contact with the annular groove provided in the second mirror plate 7. The annular groove communicates with the stamper suction passage 11, and since the stamper suction passage 11 is connected to a vacuum pump or the like separately provided outside the mold, the stamper 8 is constantly sucked and the surface of the second mirror plate 7 is attracted. It is fixed to.

The stamper retainer 13a is an annular member having three inner circumferences and is fixed to the movable frame 6. Of the three inner peripheries, the first inner perimeter is a recess 13c facing the trapezoidal slope portion of the first mirror surface plate 4, and the second inner perimeter is a cavity that is continuous with the recess 13c and forms the end face of the cavity 9a. End face 14
The third inner circumference has a larger inner diameter than the other two inner circumferences, and is configured to come into contact with the outer circumference of the second mirror surface plate 7. The cavity end surface 14a is a surface having a large inner diameter A on the stamper 8 side and a small inner diameter B on the first mirror surface plate 4 side, and the line connecting A and B is a straight line on the cross section, but it is an appropriate curve or broken line. May be. The cavity end surface 14a projects in the stamper 8 direction with respect to the third inner circumference, and its tip end faces the surface of the stamper 8 with a minute gap therebetween. A step portion between the protruding portion of the cavity end surface 14a and the third inner circumference forms an annular space between the second mirror surface plate 7 and the stamper 8, and the air outlet 12 is formed in the annular space.
, And the compressed air for releasing the disk substrate 15a is supplied from an air pressure source connected to the air outlet 12 outside the mold.

The disk substrate mold has been described as a structure in which the stamper 8 is placed on the movable mold 1a. However, the structure of the movable mold 1a and the fixed mold 2 is reversed in FIG.
Needless to say, even if the stamper 8 is mounted on the fixed mold 2, the present invention is similarly applied.

Next, the situation of molding the disk substrate 15a with the disk substrate mold will be described. Although not shown, the molten resin injected from the nozzle of the injection device flows into the cavity 9a through the sprue bush of the mold. After the predetermined amount of the cavity 9a is filled with the molten resin, the movable mold 1a slightly opened by the resin pressure is clamped with a predetermined force, and the cavity 9a is uniformly filled with the molten resin. The molten resin becomes a disk substrate 15a with a central opening perforated by a cutter at an appropriate time during the process of cooling and solidifying in the cavity 9a. Thereafter, the movable mold 1a is separated from the fixed mold 2, and the mold is opened. At this time, since the end surface 19 of the disk substrate 15a is engaged with the cavity end surface 14a, it is easy to open the movable mold 1a. In addition, the mold can be released from the surface of the first mirror plate 4 with stability.

The disk substrate 15a, which has been opened to a predetermined position together with the movable mold 1a, has compressed air from the air outlet 12 between the stamper 8 and the disk substrate 15a through a minute gap between the stamper 8 and the stamper retainer 13a. Since it is released from the mold in advance and cooled sufficiently by this time, its end face 19 has its cavity end face 14a.
Although it has an engaging relationship with and has a small inner diameter B on the side of the first mirror surface plate 4 of the cavity end surface 14a, it can be taken out based on the contraction of the disk substrate 15a. Specifically, in the case of a compact disc, the dimension A is 120.8 mm to 121.1 mm and the dimension B is 120.5 mm to 120.8 mm. On the other hand, the dimension of the disk substrate formed by the cavity having the above A and B dimensions is C is 120.0 mm to 120.3 m.
m, and D is 119.7 mm to 120.0 mm. This satisfies the standard of 120.0 ± 0.3 mm, and even when the dimension C is maximum (120.3 mm), it is smaller than the minimum dimension B (120.5 mm), so the disk substrate 15a can be easily moved to the movable mold 1a. Can be taken out from. In addition, the inclination of the end surface 19 is set to the signal surface 16 of the disk substrate 15a
When expressed as an angle α with the perpendicular to the corner portion 18 of α, α is preferably in the range of 7 degrees to 14 degrees in view of the above AB size and the effect of handling.

On the disk substrate 15a thus formed, the minute projections formed on the stamper 8 are transferred as pits to the signal surface 16 on the stamper 8 side. A metal thin film is vapor-deposited on the signal surface 16 of the disk substrate 15a after molding, and a protective film is further formed, and printing or label application is performed as necessary to complete a disk.

[0015]

Since the disk substrate mold of the present invention is configured as described above, the mold release of the disk substrate 15a can be performed extremely easily and stably, and the disk substrate 15a remains on the fixed mold 2. In addition, it is possible to prevent a drop in the middle of mold opening and to eliminate the appearance defect on the surface of the disk substrate 15a due to the mold release defect. Further, since the corner portion 18 of the signal surface 16 (print surface) has an acute angle, the disk substrate 15a has a shape.
When stacked with the signal side facing up, the disks are easy to grip and are extremely easy to handle.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a mold of the present invention.

FIG. 2 is a cross-sectional view of both ends of the disk substrate of the present invention molded by the mold of FIG.

FIG. 3 is a sectional view of a main part of a conventional mold.

FIG. 4 is a cross-sectional view of both ends of a conventional disk substrate molded by the mold of FIG.

[Explanation of symbols]

1a, 1b ……… Movable mold 2 ……… Fixed mold 3 ……… Mounting plate 4 ……… The first mirror plate 5: Fixed frame 6 ……… Movable frame 7 ……… Second mirror plate 8 ……… Stamper 9a, 9b ……… Cavity 10 ... Air exhaust path 11 …… Stamper suction path 12 ... Air suction path 13a, 13b ...... Stamper retainer 13c …… Recess 14a, 14b ... Cavity end face 15a, 15b ...... disk substrate 16 …… Signal side 17 ... Reading surface 18 ... Corner 19 …… End face

Claims (2)

[Claims] 1. A stamper mounted on one of a movable mold and a fixed mold and having a trapezoidal cross section, and a second mirror plate provided on the other of the movable mold and the fixed mold. In a disk substrate mold including a stamper retainer for holding the stamper and having a cavity formed by the first mirror surface plate penetrating into a recess of the stamper retainer, a cavity end surface of the stamper retainer is a radial surface of the stamper. Is large, and a cavity is formed so that the diameter is small on the side of the first mirror surface plate. 2. The disk substrate metal according to claim 1, wherein an angle formed by a vertical line at a corner of a signal surface of the disk substrate formed by the cavity and an end surface of the disk substrate is 7 degrees to 14 degrees. A disk substrate molded with a mold.