JPS5916333B2 - Kaitenki Rokubaitaino Master - Banno Seizouhouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Information signals such as video signals are recorded on a disc-shaped recording medium: For example, there are disc-shaped recording media that are optically recorded using laser light and then optically reproduced.

The present invention relates to a method for manufacturing a master plate for such a disc-shaped recording medium. The master plate for this type of recording medium has conventionally been manufactured at zero as follows.

That is, as shown in FIG. 1, first, a photoresist layer 2 serving as a recording layer is deposited on the surface of a disc-shaped insulating substrate 1 made of glass, for example (FIG. 1A), and then this photoresist layer 2 is By exposing the photoresist layer 2 to laser light and developing it, information signals such as video signals are recorded on the photoresist layer 2 (see figure B), and then electroless plating is applied to form a conductive layer on the surface. 4 is deposited to form the record carrier 3 (FIG. C), and then this record carrier 3 is electrolytically plated with 0
to form a plating layer 5 (D in the same figure).

Then, the conductive layer 4 and the plating layer 5 are peeled off from the insulating substrate 1, and the photoresist adhering to the conductive layer 4 is washed away to form a master plate 6. By the way, in such a manufacturing method, it is desirable that the conductive layer 4 formed by electroless plating is as thin as possible in order to prevent the formation of pinholes and peeling off due to plating stress.

However, when the conductive layer 4 is thin, the electrical resistance increases when a current is passed through it during electrolytic plating.
Each part of the conductive layer 4 covering the recording layer 2 does not have an equal potential, and it becomes difficult to electrolytically plate the parts where the voltage has dropped, and the conductive layer 4 is exposed to the electrolytic plating solution without forming the plating layer 5. It will twist and melt. Also, when performing electrolytic cleaning with the record carrier 3 facing the anode,
As shown in FIG. 2, the current is concentrated at the corner portion of the outer peripheral end of the recording carrier 3, so that the plating layer 5 is formed thicker in this portion than in other portions.

Therefore, in order to obtain a master plate having a uniform thickness in the radial direction of the record carrier 3, it is necessary to cut out the outer peripheral portion as shown in FIG. This means that only the master board can be obtained, which is extremely inefficient. In view of the above-mentioned points, the present invention provides a method for manufacturing a master board that does not cause the above-mentioned drawbacks even when the conductive layer 4 is thin, and that also allows a master board of approximately the same size as the insulating substrate 1 to be obtained. The present invention provides a method.

The method of the invention will now be explained with reference to FIG.

In the present invention, the steps up to the formation of the recording carrier 3 are completely the same as those of the conventional method, and the present invention is characterized by the step of forming the plating layer 5 by electrolytic plating. That is, in the present invention, the second
As shown in the figure, a correction stand 7 made of, for example, metal and having a shape in which an annular protrusion 7a is formed on one side of a disk is prepared, and the record carrier 3 is housed in this correction stand 7.

A through hole 8 is formed in the center of the record carrier 3, and a thread 9 is formed in the center of the correction base 7.
By screwing the conductive screw 10 into the main screw 9 of the correction table 7 through the through hole 8, the record carrier 3 is fixed to the correction table 7, and the surface of the record carrier 3 on the recording layer 2 side is fixed. The opposite surface is brought into close contact with the correction table 7. In addition, 1
2 is a conductive spacer. In this case, the height H of the annular protrusion 7a of the correction table 7 is selected so that its upper surface and the surface of the recording layer 2 side of the record carrier 3 are at the same height.

Further, the length L from the center position of the correction table 7 to the inner wall of the annular protrusion 7a is made slightly larger than the sum R of the radius of the substrate 1 and the thickness of the conductive layer 4. Projection 7a
A gap 11 is formed between the inner wall of the record carrier 3 and the outer periphery of the record carrier 3. Then, the record carrier 3 stored in the correction table 7 is immersed in an electrolytic plating solution, which is used as a cathode, and the correction table 7 is placed with the surface of the record carrier 3 facing the recording layer 2 facing the anode. Perform electrolytic plating while rotating.

In this way, the plating current 1 is applied to the part of the conductive layer 4 of the recording carrier 3 that covers the recording layer 2; the part of the conductive layer 4 that covers the outer peripheral surface of the substrate 1; flows with the correction table 7 on the opposite side (path 0), and since the screw 10 is a conductor at this time, the plating current flows into the recording carrier 3.
A part covering the recording layer 2 of the conductive layer 4, a screw 10, and a correction table 7.
The plating current spreads over a wide area, so the potential of the conductive layer 4 becomes equal everywhere,
A plating layer 5 is uniformly formed on the surface of the recording carrier 3 on the recording layer 2 side.

According to the above-described method of the present invention, the recording carrier 3 is housed in the correction table 7 made of conductive metal, and one side is brought into close contact with the correction table 7, so that the potential of the portion of the conductive layer 4 to be electrolytically plated is adjusted. Since the electrical potential can be made equal, even if the conductive layer 4 is thin, it will not be dissolved by the electrolytic plating solution, and the entire recording layer 2 can be completely covered, making it possible to create a master with the recording layer 2 accurately transferred. You can get a board.

At this time, if the radius of the record carrier 3 is small, it is sufficient to make the conductive layer 4 equipotential by flowing the plating current 1 through the path 0), but even if the radius of the record carrier 3 is large, By causing the plating current I to also flow through the path (4) as in the example, it is possible to sufficiently equalize the potential in the same way.

Furthermore, according to the method of the present invention, the conductive layer 4 may be thin, so pinholes will not occur and it will not peel off due to plating stress.

Furthermore, by providing the annular protrusion 7a that surrounds the record carrier 3 on the correction table 7, current concentration mainly occurs at the corner portion of the outer peripheral end of the annular protrusion 7a, and therefore the record carrier 3 Since the plating layer 5 formed on the side of the recording layer 2 has a substantially uniform thickness, the plated layer 5 that is peeled off from the insulating substrate 1 can be used as a master plate as it is, and
You can get a master plate with the same radius as .

FIG. 3 is a characteristic curve diagram showing the thickness at each position in the radial direction from the center of the master plate 6, and the broken line in the figure shows the characteristics when electrolytic plating is applied without using the correction table 7 as in the conventional case. The solid line in the figure shows the characteristics when electrolytically plated by the method of the present invention.

In this case, a copper plate with a thickness of 2 (V7!) is used as the correction table 7, the radius of the record carrier 3 is 14GTrL, the thickness is 5 mm, and the width of the gap 11 is 2 mm.
Instead of a disk with an annular projection formed on one side, an annular plate with an annular projection formed on one side can also be used, and the correction table 7 can be made by, for example, forming the surface of a plastic molded product. It may be something covered with metal.

Further, even if the height H of the annular protrusion 7a is lower than the thickness of the recording carrier 3, substantially the same effect as in the above case can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing steps of an example of a conventional method for manufacturing a master plate for a rotating recording medium, FIG. 2 is a diagram showing main steps of a method for manufacturing a master plate for a rotating recording medium according to the present invention, and FIG.
The figure is a diagram for explaining the effect. 1 is an insulating substrate, 2 is a photoresist layer, 3 is a record carrier,
4 is a conductive layer, 5 is an electrolytic plating layer, 6 is a master plate, 7 is a correction table, and 7a is an annular protrusion thereof.

Claims (1)

[Claims] 1 A recording carrier having a conductive layer formed by electroless plating over the entire surface of a disc-shaped insulating substrate having a recording layer on one side, and a recording carrier having a surface made of conductive metal and having an annular protrusion on one side. Then, a correction table is prepared in which the inner radius of the annular protrusion is slightly larger than the radius of the record carrier, and the height of the annular protrusion is selected to be equal to or less than the height of the record carrier. A record carrier is placed in the correction table, the annular protrusion proximately surrounds the record carrier, and the surface of the record carrier opposite to the surface on the recording layer side is brought into close contact with the correction table. and in this state, forming a plating layer on the surface of the recording layer side of the recording carrier by electrolytic plating,
In this case, the plating current is guided to the opposite surface through the side surface of the record carrier, and then the plating layer and the conductive layer are peeled off from the insulating substrate to obtain a master plate for a rotating recording medium. Method.