JPH0561097B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method and apparatus for producing a duplicate disc used for a digital code optical disc, a video disc, a PCM code audio optical disc, and the like.

[Background of the invention]

The conventional duplication method uses a replica substrate and a stamper with a slightly smaller diameter, pours an ultraviolet curing resin (hereinafter referred to as UV resin) between the substrate and the stamper, and rotates them while applying UV light.
The resin was uniformly exposed to light to cure it. At this time, the relative positional relationship between the stamper and the substrate may shift, and if there is a foreign object between them, this will rub the stamper surface and cause scratches on the surface.
As a result, the quality of the replicas deteriorated. Incidentally, it is impossible to imagine a case where there is no foreign material, and it seems likely that the stamper will be scratched as much as possible.

[Purpose of the invention]

An object of the present invention is to provide a method and apparatus for producing high-quality reproduction disks while preventing the occurrence of scratches on the stamper, which are the disadvantages of the conventional method described above.

[Summary of the invention] When making a duplicate disk, the inner circumferential portion that does not interfere with the replica is exposed in advance, and the UV resin in that portion is cured. Note that at this time, the stamper and the substrate are not rotated. After this, even if the stamper is rotated, the inner circumferential portion is already bonded, the relative position of the stamper and the substrate remains unchanged, and the scratches on the stamper that conventionally occur are eliminated, making it possible to produce a high-quality replica.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, an ultraviolet curable resin 3 is applied to a stamper 1 having a pattern of concave and convex portions according to recorded information, and a replica disk substrate is formed on the stamper 1.
A light-transmitting disk 4 such as a transparent glass plate or a transparent acrylic plate is pressed. This state is shown in A. Next, as shown in the stopped state B, a mask 5 that partially blocks the light irradiation is provided on the light-transparent disc 4, and the part that exits from the mask 5, for example, the inner peripheral part where there are no irregularities due to recorded information. 7 is precured by light beam 6. Next, as shown in C, the portion 8 with the unevenness signal is hardened, but at this time,
The resin is cured by exposing to light through a mask 9 so as not to cure the part outside the stamper 1. The inner diameter of the part of the mask 9 that prevents light transmission is the same as that of the stamper 1.
If the outer diameter is slightly smaller than the outside diameter, it has a masking effect that blocks light. It should be noted that during this exposure, it is better to rotate the entire body and expose it to the light so that it can be cured uniformly.

Here, as the material of the mask 5 or the mask 9, a metal plate is generally used, but glass,
Use a transparent plate such as acrylic with a substance attached to it that reflects or absorbs the light necessary for the resin to harden, a plate-shaped plate of the previous substance, or a combination of the above. Is possible.

Note that even if the mask 9 is omitted, the effects of the present invention do not change.

In addition, the exposed portion 7 in FIG. 1B is
High quality replicas can be produced by curing parts of the replica that do not require uniform curing.

Further, in the above embodiment, the mask 5 and the mask 9 are separate, but the same mask may be used with different opening diameters. That is, the aperture has a variable aperture structure so that the aperture diameter can be arbitrarily selected. Further, as the material for this, a material that reflects or absorbs the light beam necessary for hardening the resin can be used.

In addition, the exposed portion 7 in FIG. 1B is
High quality replicas can be produced by curing parts of the replica that do not require uniform curing.

By using a mask with a variable aperture, partial exposure and main exposure can be performed in one exposure, and the replica production time can be shortened.

A specific example of such a variable aperture mask will be described.

FIG. 2 is an example of a variable aperture mask. Transparent substrates 5-1 and 5-2 are coated with Al etc. 5-3 and 5-5, respectively.
Two sheets 10-1 and 10-2 with -4 attached are prepared, and first, the mask 10-1 is overlapped on 10-2 and exposed. Thereafter, the stamper is rotated, and then the mask 10-1 is removed and exposure is performed.
Here, Al of 5-3 and 5-4 can be easily realized by vapor deposition or by pasting a plate.

3 and 4 show other examples of variable aperture masks. This is because the opening diameter of the blade 11 is changed by the lever 12, and the state shown in FIG. 3 corresponds to the mask 5 and the state shown in FIG. 4 corresponds to the mask 9.

In addition, in the above explanation, in replica production,
Although a description has been given of a stamper using an ultraviolet curing resin, the present invention can also be applied to a replica structure having a base film (cellulose, acetate, nitrocellulose, etc.) between the stamper and the resin.

〔Effect of the invention〕

According to the present invention, the stamper, resin, and substrate are partially bonded in advance and their relative positional relationship is maintained, so even if the stamper is rotated during the exposure process, "scratches" will not occur on the stamper. This method has the effect of making it possible to produce high-quality replica disks.

[Brief explanation of drawings]

Figures 1A, B, and C are diagrams showing one embodiment of the present invention, Figure 2 is a diagram showing an example of a mask used in the present invention, and Figures 3 and 4 are diagrams showing other masks used in the present invention. It is a figure which shows an example. 1... Stamper, 3... Ultraviolet curing resin, 4...
... Replica disk board, 5, 9 ... Mask, 6
... Resin curing light beam, 5-1, 5-2 ... Mask substrate, 5-3, 5-4 ... Ultraviolet reflection, absorption layer,
11...feather, 12...lever.

Claims (1)

[Claims] 1. In a method for manufacturing a replica disk, the method comprises applying a photocurable resin onto a replica mold having irregularities according to recorded information, providing a light-transparent substrate on the resin, and then curing the resin. First, with the mold and substrate not rotating, only the inner circumferential portion, which is the part where there is no unevenness signal due to recorded information, is pre-cured with light, and then, with the mold and substrate being rotated, the unevenness is 1. A method for manufacturing a duplicate disk, characterized in that exposure from the light source is limited by changing the aperture diameter of the mask in two stages so that a portion of the signal can be cured by the light beam.