JPH0818348B2 - Optical disk injection mold - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for manufacturing a plastic substrate for an optical record disc such as a compact disc, a video disc, or an optical disc. Among them, the present invention relates to a die used for molding a substrate, which is characterized by a method of holding a stamper and a holding structure.

[Conventional technology]

In the conventional disk mold, the movable mold half 1 shown in FIG. 3 is used.
(Or fixed side mold half 2) Incorporate the mirror surface plate 3, cover the stamper 4 on it, fit the inner ring 5, then insert the fixed support rods 14 from both sides of the mold,
The convex portion of the tip of the fixed support rod 14 is formed into the concave portion 13 in the inner peripheral ring 5.
The stamper 4 was mounted on the die by fitting the stamper 4 so that the inner ring 5 was pressed down and fixed, and the outer ring 6 was fixed to the outer circumference of the stamper 4 with the bolts 7.

[Problems to be solved by the invention]

These operations had to be carried out with the mold attached to the molding machine, and the workability was extremely poor. Further, for the same reason, as shown in FIG. 4, especially, dust 16 and scratches 15 are likely to enter between the stamper 4 and the mirror plate 3, so that the stamper 4,
In the molded product 19 surrounded by the fixed-side mirror surface plate and the like, it caused local unevenness 18 of birefringence and convex defects 17.

An object of the present invention is to assemble a stamper, a mirror plate, etc., which are relatively easily scratched, outside the mold body, and replace them with clean and one-touch operation, resulting in improved workability and It is an object of the present invention to provide a mold that is less likely to cause defects.

[Means for solving problems]

The above-mentioned object is provided with a mold body and a unit which is composed of at least a stamper on which information and guide grooves are engraved in advance, a mirror surface plate, an inner peripheral ring and an outer peripheral ring, and which can be integrated by assembly outside the mold main body. The inner ring has a protruding portion that is opposite to the stamper mounting portion of the integrated unit and has a spline on the outer peripheral surface thereof, and the mold body has a spline on the inner peripheral surface. It is characterized in that it has a concave portion, and the integrated unit is fixed to the mold body by rotating the integrated unit and fitting the spline provided on the protruding portion into the spline of the concave portion. This is achieved by a die for ejecting an optical disc. The mold body is generally provided with not only fixing means corresponding to the fixing means on the unit side, but also bolt holes for fixing the outer peripheral ring.

[Action]

In such a mold of the present invention, avoiding attaching the stamper to the movable side mirror surface plate in the mold mounted on the molding machine as is conventionally done, and setting the stamper on the mirror surface plate in a clean environment. Therefore, local unevenness of birefringence and convex defects do not occur, and the unit can be attached and detached by an extremely simple operation of rotating the unit, and workability is also improved.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic view showing the structure of an embodiment of the mold of the present invention. In this mold, the stamper 4, the mirror surface plate 3, the inner peripheral ring 5, the outer peripheral ring 6, and the spacer 8 can be integrated by assembling without being assembled in the mold main body. It is referred to as a structure)). This integrated stamper structure can be attached to and detached from the mold body.

The stamper assembly can be assembled in a class 10 clean bench (a workbench in a clean room having a very high degree of cleanliness) as follows. First, the spacer 8 is washed with a solvent, the mirror surface plate 3 is placed thereon, and the stamper 4 is further placed thereon. The inner ring 5 is inserted from above. The inner ring 5 is
It has a screw portion 9 and a spline 11 for fixing it to the mold, and the fixing ring 10 tightens the three parts fitted in the inner peripheral ring 5. Finally, the outer peripheral ring 6 is put on the outer periphery of the stamper 4 and tightened with bolts 7a. This completes the stamper assembly.

The inner ring 5 is used to attach the stamper assembly to the mold body.
Insert the spline 11 provided on the mold into the spline 12 of the mold body and rotate the stamper structure. After inserting the stamper structure into the mold body, fix it with bolts 7 from above the outer ring. Can be implemented by

The shape of the spline in the above embodiment is not necessarily this shape, and a simple screw is also possible.

Further, as a means for integrally fixing the stamper, the mirror surface plate and the spacer, a fixing ring or the like may be used, or an ordinary bolt may be used for fixing. It is also possible to make the mirror plate and the spacer in one piece.

〔The invention's effect〕

In the present invention described above, (1) Since the stamper is formed as a stamper structure, the stamper can be assembled not on the molding machine but in a clean bench of class 10, for example. There was no concern that foreign matter would enter between the stamper and the mirror surface, and the defective molded product was resolved.

(2) Since the mirror plate can be removed from the mold, when the mirror plate is scratched or the like, it can be immediately replaced with a spare, and the molding efficiency is significantly improved.

(3) With the conventional mold, the time required to replace the stamper is
It took about 10 to 20 minutes, and the molding interruption time was long, but in the mold of the present invention, a method of providing a spline-shaped fixing mechanism on the inner peripheral ring and inserting the stamper structure into the mold half rotation as it is As described above, it becomes possible to easily fix it, and the time required for replacing the stamper is shortened to about 5 minutes.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of a typical example of a mold in the present invention, FIG. 2 is a diagram showing an inner ring which is particularly important among them, and FIG. 3 is a diagram showing an example of a conventional mold, FIG. 4 is a diagram showing defects found in a conventional molded product. 1: Movable mold half, 2: Fixed mold half 3: Movable mirror plate, 4: Stamper 5: Inner ring, 6: Outer ring 10: Fixed ring 11: Inner ring spline 12: Movable spline 13: Fixed concave part of conventional inner ring 14: Fixed type support rod 15: Scratch, 17: Convex defect 18: Local unevenness of birefringence 19: Molded product, 20: Fixed type mirror plate

Claims (1)

[Claims] 1. A unit comprising a stamper, a mirror plate, an inner peripheral ring and an outer peripheral ring in which information and guide grooves are preliminarily engraved and which can be integrated by assembly outside the mold main body, and a mold main body. The inner ring has a protruding portion that is opposite to the stamper mounting portion of the integrated unit and has a spline on the outer peripheral surface thereof, and the mold body has a spline on the inner peripheral surface. It is characterized in that it has a concave portion, and the integrated unit is fixed to the mold body by rotating the integrated unit and fitting the spline provided on the protruding portion into the spline of the concave portion. Mold for ejecting optical discs.