JPS58704Y2 - plating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plating device for forming a uniform plating layer on the surface of a disc body, and particularly to a cathode shield plate having an effect equivalent to that of an auxiliary cathode.

Recently, development of so-called video discs (hereinafter referred to as discs), which are record-like high-density recording carriers that can simultaneously reproduce video and audio signals, has been rapidly progressing.

Among these methods, there is a method of mechanically reproducing signals from a disk on which information signals are recorded as mechanical unevenness.

There is a copper plating method as a means of manufacturing a recording master for such a mechanical disk.

In such a video player system, if the disc size is, for example, 300 φmm, the master disc size must be at least 350 φmm; on the other hand, in order to use it as a recording master disc, It is essential that the copper plating layer be homogeneous and uniform to ensure stable machinability and a good signal-to-noise ratio during playback.

In other words, if the thickness of each part of the disk plating layer is average, the current density of each part is average.

), and must be uniform and homogeneous in terms of metallographic structure.

Generally, when a disk is electrolytically plated, the plating layer 2 on the outer periphery of the disk-shaped object 1 becomes thicker, as shown in FIG.
Uneven thickness occurs.

In order to reduce this thickness unevenness, it has been considered to provide an auxiliary cathode.

That is, as shown in FIG. 2, by providing a metal auxiliary cathode 3 close to the object to be plated 1, the electric field around the object to be plated 1 is adjusted, the current density is averaged, and the plating layer is This is intended to suppress uneven thickness.

However, as shown in FIG. 2, the ring-shaped auxiliary cathode 3
In the configuration in which the auxiliary cathode 3 and the object to be plated 1 are held, it is difficult to adjust and maintain the relative positional relationship between the auxiliary cathode 3 and the object to be plated 1.

Another method for reducing thickness unevenness is to provide an auxiliary cathode as shown in FIG.

In FIG. 3, a ring-shaped auxiliary cathode holder 6 made of an insulating material such as plastic and having a diameter larger than the disc-shaped object 1 by a predetermined length has a metal that will become an auxiliary cathode on the outer periphery. A thin film conductor 7, such as tape (eg aluminum), is attached.

The auxiliary cathode holder 6 is removably fixed to the outer side of the object to be plated 1 by plastic screws 8 and metal screws 9 and 10.

At this time, the object to be plated 1 and the holder 6 are adjusted to have the same central axis.

Here, the metal screw 9 is used to bring the object to be plated 1 and the auxiliary electrode 7 to the same potential, and the panel screw 10 is used to conduct electricity.

According to this method, the positional relationship between the object to be plated 1 and the auxiliary electrode 7 can be easily maintained, and the position does not change during the plating operation.

However, since the surface area of the auxiliary electrode plated on the auxiliary electrode holder increases in accordance with the cumulative plating time, the current density changes.

For this reason, the total current must be determined after calculating what percentage of the total is to be plated on the object to be plated.

Further, there are other problems such as the need to replace the auxiliary electrode after use for a predetermined period of time.

A configuration shown in FIG. 4 can be considered as a solution to the above-mentioned problems.

In this case, cathode ring-shaped shield plates 11 having the same effect as an auxiliary cathode are positioned on both sides of the object to be plated 1, and the relative positional relationship is maintained by spacers 12.

The object to be plated 1 and the spacer 12 are fixed with an insulating material such as a plastic screw.

Although not shown, the cathode ring-shaped shield plate 11 and the spacer 12 are fixed with an insulator such as a plastic screw.

The metal screw 10 serves to fix the object 1 to be plated and to conduct electricity.

Cathode ring-shaped shield plate 11. The spacer 12 may be any insulating material as long as it is not corroded by the plating solution.

FIG. 5 shows a specific example of the plating bath used in the experiment.

Anode 13. In addition to the plating solution 14, a cooling pipe, a plating solution blowing nozzle, etc. are required, but they are omitted because they are not directly related.

However, the size of the plating bath and the distance between the two anodes are related.

The outer diameter of the ring-shaped shield plate 11 for the cathode is
The inner diameter is larger than the outer diameter of the object 1 to be plated.

When plating is performed using the cathode ring-shaped shield plate 11 having such a structure, concentration of current near the outer periphery of the object to be plated is prevented, and the current density in each part of the disk plating layer is approximately averaged.

If the outer diameter of the disk-shaped object to be plated is aφ, then the outer diameter of the cathode ring-shaped shield plate 11 is 1.1a to 1.4a, the inner diameter is 0.7a to 0.9a, and the length of the spacer is covered. The distance from both sides of the plated object to the shield plate 11 is 0.13-0
．． If the current density is set to 2a, the current density in each part of the disk plating layer will be approximately averaged.

More specifically, the plating tank shown in Fig. 5 and the cathode ring-shaped shield plate having the structure shown in Fig. 4 were used, and the outer diameter was 350 mm.
When plating a disk with a diameter of φmm and a thickness of 1Qmm, according to experiments, the outer diameter of the ring-shaped shield plate for the cathode should be 430φm.
The best results were obtained when the inner diameter was 280 mm and the distance between the object to be plated and the shield plate was 45 mm.

That is, the current density at each part of the disk plating layer is approximately averaged.

The present invention aims to further average the current density in each part, and FIG. 6 shows an embodiment of the present invention.

In FIG. 6, the same parts as 1 and 4 are given the same numbers, and their explanations are omitted.

15 is a second cathode ring-shaped shield plate, which is an insulator.

This second ring-shaped cathode shield plate 15 is provided between the first cathode ring-shaped shield plate 11 and the object 1 to be plated.

The outer diameter of the second ring-shaped shield plate 15 for cathode is smaller than the outer diameter of the first ring-shaped shield plate 11 for cathode.
The inner diameter of the cathode long-shaped shield plate 15 is made larger than the inner diameter of the first cathode ring-shaped shield plate 11.

When plating is performed using a cathode ring-shaped shield plate having such a structure, concentration of current near the outer periphery of the object to be plated is prevented, and the current density in each part of the disk plating layer is averaged.

When plating a disc-shaped object to be plated, the outer diameter is assumed to be a, and the diameter dimension at the point where the plating thickness increases by 10% or more compared to the inner circumference plating thickness is determined.

When plated with the configuration shown in Figure 4, it is 0.91 a, and the
When plated with the embodiment of the present invention shown in the figure, the current density is 0.932, and the current density is more averaged to the outer periphery when plated with the embodiment of the present invention.

That is, compared to the configuration shown in FIG. 4 in which the current density around the outer circumference of the object to be plated 1 is averaged using only one ring-shaped shield plate 11 for the cathode, the configuration of the present invention averages the current density around the outer circumference of the object to be plated 1 by using only one ring-shaped shield plate 11 for the cathode. This is a ring-shaped shield plate for the cathode, and because it averages the current density, it can further average the current density.

If the outer diameter of the disk-shaped object to be plated is aφ, then the outer diameter of the first cathode ring shape and shield plate is 1.1a to 1.4a,
The inner diameter is 0.7a to 0.9a, the distance between the plating surface of the object to be plated and the first shield plate is 0.1a to 0.2a,
The outer diameter of the second cathode ring-shaped shield plate is a ~1.1
a, the inner diameter is Q, 8a-a, the distance between the plated surface of the object to be plated and the second shield plate is 0.03a to 0°07a
When the shield structure is adopted, the current density in each part of the disk plating layer becomes more average.

Using the plating tank shown in Fig. 5 and the cathode ring-shaped shield plate having the structure shown in Fig. 6, the outer diameter is 350φm and the thickness is 1Qm.
According to experiments, when plating a disk of m, the outer diameter of the first cathode ring-shaped shield plate 11 is 430 φ mm, the inner diameter is 280 φ mm, the distance from the object to be plated is 45 mm, and the second
The outer diameter of the ring-shaped shield plate 15 for the cathode is 380φmm.
The best results were obtained when the inner diameter was 320 mm and the distance between the plated surface of the object to be plated and the second shield plate 15 was 18 mm.

That is, the current density in each part of the disc plating layer is averaged.

As described above, the present invention has many advantages as follows.

1. The current density in each part of the disc plating layer is averaged, and the thickness is constant.

2. Current density does not change during plating work because no auxiliary electrode is used.

3. Since no auxiliary electrode is used, 100% of the object to be plated is plated.

4. Current density can be easily controlled.

[Brief explanation of the drawing]

Figure 1A is a plan view showing the plating layer attached to a disc-shaped object to be plated, the opening is a sectional view of the same, Figure 2 is a perspective view showing the structure of a conventional auxiliary cathode, and Figure 3A is a conventional auxiliary cathode. A plan view showing the structure of the cathode, a cross-sectional view of the opening, and a cross-sectional view showing an example of a cathode shield plate considered as a preliminary stage of the present invention.
The opening is a plan view of the same, Figure 5A is a side view of the plating tank used in the experiment, the opening is a front view of the same, and Figure 6A is a sectional view showing an embodiment of the plating apparatus of the present invention, the opening is the same plane. It is a diagram. 1...Plated layer, 2...Plated layer,
3... Auxiliary cathode, 4... Arm, 5...
... Support arm, 6 ... Auxiliary cathode holder, 7 ... Thin film conductor, 8 ... Plastic screw, 9, 10 ... Metal screw, 11...
... Ring-shaped shield plate for cathode, 12 ... Spacer, 13 ... Anode, 14 ... Plating solution, 15 ... For second cathode Ring-shaped shield plate.

Claims (1)

[Scope of utility model registration request] A disk-shaped object to be plated having an outer diameter larger than that of the disk-shaped object and an inner diameter of the disk-shaped object to be plated is located at a predetermined distance from each side of the object to be plated, facing each side of the disk-shaped object to be plated. A first annular body made of a smaller insulator is disposed between the first annular body and the disc-shaped object to be plated. A plating apparatus comprising a second annular body made of an insulator that is larger than the inner diameter of the annular body and smaller than the disc-shaped object to be plated.