JP2001167512A - Method for manufacturing turntable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turntable which can drastically lessen the wobbling of surface occuring in a recording medium under rotation and can drastically reduce safety and the burden in terms of environment equipment. SOLUTION: A base material of the turntable 1 is molded of a resin composition 2 consisting of a thermoplastic resin (PPS), inorganic fillers (whiskers), etc. A receiving surface 2a to be placed with the disk-like recording medium 5, a center hub 2b for centring a central hole 5a of the recording medium 5 and a fitting hole 2c to be pressed fitted to a revolving shaft 4a of a spindle motor 4 are formed at this resin composition 2. Next, the resin composition is subjected to a blasting treatment in the state of masking center hub 2b, by which the surface roughness Rmax of the resin composition 2 exclusive of the center hub 2b is polished until >=15 μm is attained and thereafter the resin composition 2 is successively subjected to catalyst impartation, activation treatment and electroless plating, by which a plating film 3 is formed in the part subjected to the blasting treatment of the resin composition 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a turntable which rotates by mounting a disk-shaped recording medium such as a CD or a DVD, and more particularly to a method for securing a coefficient of friction for the disk-shaped recording medium. It relates to a force applying means.

[0002]

2. Description of the Related Art When recording and / or reproducing information on a disk-shaped recording medium such as a CD or DVD, a spindle motor is driven while the recording medium is chucked between a turntable and a clamper member. By rotating the turntable as a source, the recording medium rotates integrally with the turntable. This turntable is made of a resin molded product such as PC (polycarbonate), and has a center hub protruding at the center of the upper surface thereof, and a ring-shaped receiving surface formed at the periphery of the upper surface. Then, when the recording medium is placed on the receiving surface of the turntable, the center hole of the recording medium fits into the center hub, so that the recording medium is centered with respect to the turntable. The recording medium is rotated in this state.If the friction coefficient of the turntable with respect to the recording medium is small at that time, a slip occurs between the recording medium and the turntable. In order to rotate the turntable, a large frictional force must be applied to the turntable.

Hitherto, as a means for imparting a frictional force to such a turntable, a method of attaching a sheet to a receiving surface of the turntable or painting the receiving surface of the turntable has been known. The former sheet sticking method is
A sheet made of urethane rubber or the like having a large coefficient of friction is formed in a ring shape, and this sheet is adhered to the receiving surface of the turntable with a double-sided adhesive tape or the like. Is sprayed onto the receiving surface of the turntable.

[0004]

However, among the above-mentioned prior arts, the former sheet sticking method involves manually sticking the sheet to the receiving surface of the turntable, so that the sheet is misaligned when the sheet is stuck. In addition to the problem of easy workability and poor workability, the thickness of the sheet and double-sided adhesive tape becomes uneven at each part, causing a waviness phenomenon called surface runout on the rotating recording medium, and the defect rate There was also a problem that it became high. On the other hand, the latter coating method is more suitable for mass production than the sheet sticking method, but if the amount of one spraying is increased, the film thickness becomes uneven, so that the spraying and the baking / drying process are repeated a plurality of times. It is necessary, and even if the coating is performed in such a large number of steps, the accuracy of the film thickness does not become high enough to completely eliminate the runout, so that the defect rate has not been reduced significantly. There was a problem.

[0005]

SUMMARY OF THE INVENTION The present invention is an improvement on a conventionally known plating technique for plastics, in which an electroless plating without an etching step is applied to a resin composition as a base material of a turntable. Thereby, the coefficient of friction of the turntable with respect to the disk-shaped recording medium is ensured. When a turntable is manufactured in this manner, a plating film having a uniform film thickness and a high coefficient of friction can be formed on the receiving surface of the turntable, thereby greatly reducing surface runout occurring on a rotating recording medium. In addition, since an etching process is not required, there is a cost advantage that the burden on safety and environmental facilities is greatly reduced.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, a disk-shaped recording medium has a center hub in which a center hole is centered, and a receiving surface on which the recording medium is placed, and rotates in conjunction with a rotation shaft of a motor. In the method for manufacturing a turntable, after molding the base material of the turntable with a resin composition comprising a thermoplastic resin and an inorganic filler, at least a portion of the resin composition corresponding to the receiving surface is subjected to a blast treatment. Then, the surface roughness Rmax was adjusted to 15 μm or more, and thereafter, the catalyst was applied, activated, and electrolessly plated.

The thermoplastic resin used in the present invention is not particularly limited, but a hard resin such as PC (polycarbonate) or PPS (polyphenylene sulfide) is preferable.
The inorganic filler used in the present invention may be in a powder form or a fibrous form, but whiskers are particularly preferable as the fibrous inorganic filler.

According to the turntable manufactured by the above method, a plating film having a uniform thickness and a large friction coefficient can be formed on the receiving surface of the turntable. Since the runout can be greatly reduced and the etching process is unnecessary,
There is a cost advantage that the burden on safety and environmental facilities is greatly reduced.

In the above configuration, since the plating film has a large adhesion strength at the blast-treated portion, it is necessary to at least blast the receiving surface of the turntable on which the recording medium is placed. However, since it is necessary to reduce the coefficient of friction for the center hub where the center hole of the recording medium is centered, it is preferable to perform the blasting while masking the portion of the resin composition corresponding to the center hub.

Further, in the above configuration, electroless plating is continuously performed from the receiving surface of the resin composition to the inner wall of the fitting hole via the back surface, and the rotating shaft of the motor is pressed into the fitting hole. Then, the electric charge charged on the rotating recording medium can be released from the plating film through the rotating shaft, and the generation of noise can be suppressed.

[0011]

Embodiments will be described with reference to the drawings.
FIG. 1 is a configuration diagram showing a state in which a turntable is attached to a rotating shaft, and FIG. 2 is an explanatory diagram showing a manufacturing process of the turntable.

As shown in FIG. 1, a base material of a turntable 1 is a resin composition 2 comprising a thermoplastic resin and an inorganic filler.
The resin composition 2 has a receiving surface 2a protruding in a ring shape at the periphery of the upper surface. Also,
A center hub 2b is formed to project from the center of the upper surface of the resin composition 2, and a fitting hole 2c is formed at the center of the center hub 2b. Further, a plating film 3 such as nickel plating or copper plating is formed on the surface of the resin composition 2, and the plating film 3 is continuously applied to a portion except for the center hub 2b. The thermoplastic resin used in the resin composition 2 is PC (polycarbonate).
A resin having high hardness called engineering plastic such as PPS (polyphenylene sulfide) or the like is preferable. In the present embodiment, PPS is used. Also,
The kind of the inorganic filler used in the resin composition 2 is not particularly limited, but it is preferable that the weight percentage is larger than that of the thermoplastic resin. In this embodiment, whiskers are used as the fibrous inorganic filler. .

The fitting hole 2c is press-fitted and fixed to the rotating shaft 4a of the spindle motor 4,
When the turntable 1 is rotated with the drive source as a drive source, the disc-shaped recording medium 5 such as a CD or DVD placed on the receiving surface 2a is integrally rotated. In this case, the recording medium 5 is urged toward the turntable 1 by receiving a clamping pressure from a clamper member (not shown), and the center hole 5a of the recording medium 5 fits into the center hub 2b, whereby the turntable 1 is rotated. Centered on 1. Therefore, information can be recorded and / or reproduced on the recording medium 5 by transferring the optical pickup (not shown) in the radial direction of the recording medium 5 that is rotationally driven as described above.

Next, a method of manufacturing the turntable 1 configured as described above will be described with reference to FIG. First, PPS1
00% by weight and 200% by weight of inorganic filler containing whisker
The resin composition 2 having the shape as shown in FIG. Thereafter, in a state where the center hub 2b is masked, the resin composition 2 is subjected to air blasting with an abrasive having a sharp particle shape, so that the surface roughness Rmax of the resin composition 2 excluding the center hub 2b.
Is polished until it becomes 15 μm or more (for example, 18 μm). In the steps up to this point, the resin composition 2 exhibits the same effect as chemically etched, and thereafter, the catalyst application and the activation treatment and the electroless plating, which are conventionally known, are sequentially performed on the resin composition 2. . As an example, the resin composition 2
Is immersed in a colloid solution of a mixture of tin ions and palladium ions for several minutes.Then, the tin layer covering the surface of the palladium is removed, and an activation treatment for exhibiting the function of the palladium catalyst is performed. The treated resin composition 2 is immersed in an electroless plating bath to form a plating film 3 such as nickel plating or copper plating. The thickness of the plating film 3 thus obtained is about several μm, shows a large adhesion strength with the resin composition 2 at the blast-treated portion, and is not formed on the center hub 2b which has not been blast-treated. After electroless plating, electroplating may be performed as necessary.

According to the turntable 1 manufactured in the above-described process, the plating film 3 having a uniform thickness and a large friction coefficient is formed on the receiving surface 2a of the resin composition 2, so that the rotating recording medium is formed. 5 can be significantly reduced, and furthermore, since an etching process is not required, there is a cost advantage that the burden on safety and environmental facilities is greatly reduced. Further, since the blasting process is performed while the center hub 2b of the resin composition 2 is masked, the plating film 3 having a large friction coefficient is not formed on the surface of the center hub 2b.
a can be smoothly fitted into the center hub 2b for centering. Further, the plating film 3 is formed on the receiving surface 2a.
To the inner wall of the fitting hole 2c through the back surface of the resin composition 2, and the rotating shaft 4a of the spindle motor 4 is press-fitted and fixed in the fitting hole 2c. 5 is transferred from the plating film 3 to the rotating shaft 4a.
Can be escaped through, and the occurrence of noise can be suppressed.

[0016]

The present invention is embodied in the form described above and has the following effects.

After molding the base material of the turntable with a resin composition comprising a thermoplastic resin and an inorganic filler, at least a portion of the resin composition corresponding to the receiving surface is subjected to blast treatment to reduce the surface roughness Rmax. When the thickness is 15 μm or more, and then the catalyst is applied, activated, and electroless plated, a plating film having a uniform thickness and a large friction coefficient can be formed on the receiving surface of the turntable. The generated runout can be greatly reduced, and
Since an etching process is not required, there is a cost advantage that the burden on safety and environmental facilities is greatly reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a state where a turntable according to an embodiment is attached to a rotating shaft.

FIG. 2 is an explanatory view showing a manufacturing process of the turntable.

[Explanation of symbols]

 Reference Signs List 1 turntable 2 resin composition 2a receiving surface 2b center hub 2c fitting hole 3 plating film 4 spindle motor 4a rotating shaft 5 disk-shaped recording medium

Claims (3)

[Claims] 1. A method for manufacturing a turntable, comprising: a center hub in which a center hole of a disk-shaped recording medium is centered; and a receiving surface on which the recording medium is placed, and which rotates in conjunction with a rotation shaft of a motor. After molding the base material of the turntable with a resin composition comprising a thermoplastic resin and an inorganic filler, at least a portion of the resin composition corresponding to the receiving surface is subjected to blast treatment to obtain a surface roughness. A method for manufacturing a turntable, wherein Rmax is set to 15 μm or more, and thereafter, catalyst application, activation treatment, and electroless plating are performed. 2. The method according to claim 1, wherein the blasting is performed in a state where a portion of the resin composition corresponding to the center hub is masked. 3. The fitting according to claim 1, further comprising a fitting hole into which the resin composition is press-fitted into the rotating shaft, wherein the electroless plating is performed through a back surface of the resin composition. A method for manufacturing a turntable, wherein the method is applied continuously to an inner wall of a hole.