JPS62173234A - Manufacture of information recording base - Google Patents

Abstract

PURPOSE:To obtain an information recording base whose welded part is beautiful and welding strength is high, by welding a disk base to which an external circumferential spacer has been welded with the other disk base through an inner circumferential spacer. CONSTITUTION:A disk base 1 and external circumferential spacer 3 are joined with each other and welded by making use of an ultrasonic horn 11. The disk bases 1, 2 are joined to each other through an inner circumferential spacer 4 having a round hole on the center so as to face to each other and a joint surface is welded at a time from one direction by making use of the ultrasonic horn 11. An unstuck joint surface between the external circumferential spacer 3 and disk base 2 is welded by an ultrasonic wave finally. An information recording base which possesses high adhesive strength and is in air sandwich structure is formed in this manner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing an 18-information recording substrate, and more particularly to a method for efficiently manufacturing an information recording substrate with an air sandwich structure using ultrasonic welding technology.

(Prior art) Disc-shaped information recording used in optical discs, optical memories, etc.) IS board is a disc mounting board 2 on which a recording layer is provided on the surface of a transparent plastic material in order to transmit optical signals.
An air sandwich structure is adopted in which the recording layers are joined together via an inner spacer and an outer spacer so that the recording layers face each other and a hollow portion is formed between the recording layers.

Since the information recording board with this air sandwich structure and the recording layer are isolated from the outside, there is no chance of damage or scratches on the recording layer due to carelessness during handling, and there is no possibility of dust or foreign matter adhering to the air. It has the characteristics that there is no deterioration of the recording layer due to

Conventionally, in the production of various types of information recording substrates using spacers, two disk substrates are bonded via the spacer using an adhesive such as a thermosetting adhesive or a UV curable adhesive. . However, when bonding with an adhesive, the heat required during curing may adversely affect the disk substrate and the recording layer, and volatile components contained in the adhesive or gas generated during the curing reaction may adversely affect the recording layer. In addition,
During adhesion, excess adhesive overflows from the adhesive surface, adversely affecting the recording layer or damaging its appearance. Another problem is that the dimensional accuracy of the substrate is impaired due to uneven thickness of the adhesive.

Therefore, instead of the conventional adhesive bonding method, a technique was proposed in which a spacer and a disk substrate are bonded using ultrasonic welding (Japanese Patent Laid-Open No. 103537/1983).

[Problems with conventional technology]

According to the above publication, an inner spacer and an outer spacer are installed between two disk substrates, a horn having a diameter approximately equal to or larger than the disk is pressed from above, and each spacer is welded together ( Figure 5). but,
The information recording substrate obtained in this way has poor adhesion strength, and the two disk substrates and the spacer are easily separated, which poses a practical problem. Therefore, a method of increasing the ultrasonic output may be considered in order to improve the adhesive strength. However, when materials such as information recording substrates, which have a large projected area, are thin, and are made of brittle plastic materials with high rigidity, are irradiated with high-output ultrasonic waves,
Cracks may occur at the joint surface, especially at the joint surface with the outer circumferential spacer, or the joint may break completely, causing fragments to fly off and damage the recording layer.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a method for manufacturing an information recording substrate with high bonding strength. Another object of the invention is to
It is an object of the present invention to provide a method for manufacturing an information recording substrate having an air sandwich structure that can be bonded without the risk of damaging the recording layer portion. Still another object of the present invention is to provide a method for manufacturing an information recording substrate with excellent productivity. Still another object of the present invention is to provide a method for manufacturing an information recording substrate using ultrasonic welding.

[Means for solving problems]

That is, the present invention provides a method for manufacturing an information recording substrate with an air sandwich structure in which two disk substrates are ultrasonically welded via an outer circumferential spacer and an inner circumferential spacer.
First, the outer circumferential spacer and one side of the disk substrate are welded, then the joint surfaces of the inner circumferential spacer, the disk substrate to which the outer circumferential spacer is welded, and the opposing disk substrate are simultaneously welded from one direction, and then the outer circumferential spacer and the disk This is a method for manufacturing an information recording substrate, characterized by welding the unwelded portion to the substrate.

[For production]

The manufacturing method of the present invention will be explained below using the drawings.

As is clear from the cross-sectional view shown in FIG. 4, the information recording substrate with an air sandwich structure obtained by the manufacturing method of the present invention has two disk substrates l and 2 each having an information recording layer 5. However, an outer circumferential spacer 3 and an inner circumferential spacer 4 are provided so that the recording layers face each other and maintain a space between them.
Both spacers and the disk substrate are bonded and integrated at the bonding surface with the spacers interposed therebetween. In this embodiment, the information recording layer is formed on both of the two disk substrates, but it goes without saying that the information recording layer may be formed on only one of the disk substrates.

The following method is used to manufacture an information recording substrate having such a structure by ultrasonic welding.

That is, first, one of the two disk substrates, for example 1, and the outer peripheral spacer 3 are bonded together, and the bonded surfaces are ultrasonically welded using an ultrasonic horn 11 (FIG. 1). Through this process, a disk substrate 1 with outer circumferential spacers bonded thereto is obtained.

Next, the disk substrate 1 and the remaining disk substrate 2 on one side are joined so as to face each other. At this time, an inner peripheral spacer 4 having a circular hole in the center is interposed between both disk substrates. Then, the joint surfaces of the inner circumferential spacer 4 and both disk substrates are simultaneously ultrasonically welded from one direction using an ultrasonic pawn 11 (FIG. 2). Through this process, the two disk substrates are bonded at the joint surface with the inner spacer,
Moreover, an information recording substrate is obtained in which the bonding surface between the outer periphery spacer and the disk substrate 2 is not bonded.

Finally, the unbonded joint surfaces of the outer spacer 3 and the disk substrate 2 are ultrasonically welded. In this way, an information recording substrate is obtained in which the bonding surfaces of both the smoothers and the disk substrates are firmly bonded.

According to the above manufacturing method, since the bonding with the outer peripheral spacer having the largest projected area is performed on one side, a /8 contact with high bonding strength can be achieved even if the ultrasonic output is reduced. Furthermore, since the inner peripheral spacer has a small stepped area, it can be welded to both disk substrates at the same time with a strength of 1h1 even at low power. Therefore, the information recording substrate finally obtained is firmly bonded as a whole.

The material of the disk substrate and spacer to which the manufacturing method of the present invention can be applied may basically be any thermoplastic, such as polymethylmethycrylate-1, polycarbonate, polystyrene, poly(4-methylpentene), etc. 1. Copolymers of ethylene and cyclic olefins such as norbornene, tetracyclododecene, methyltetracyclododecene, etc., ring-opening polymers of the cyclic olefins, and water additives thereof.

In addition, the output during ultrasonic welding or the static pressure between the horn and the substrate is selected so that the above-mentioned failure of the adhesive surface due to the welding distance (ti) does not occur, but approximately 0.
It is adjusted to be within the range of 5 to 2 Kw and 0.1 to 3.0 kg/ad.

The manufacturing method of the present invention can most preferably be applied to a device with a relatively small diameter, such as an optical digital data F disk with a diameter of 13 cm.

〔Effect of the invention〕

According to the 'jA manufacturing method of the present invention, ■ an air sandwich structure information recording substrate with high adhesive strength can be manufactured, ■ there is no risk of by-products being generated during welding and damaging the recording layer, and ■ welding can be performed in a few seconds. In addition, it does not require a drying process like when bonding with adhesive, so it has excellent continuous productivity. ■ Applicable if the substrate material and spacer material are thermoplastics. ■ The bonding surface is It exhibits effects such as /8 contact can be made even if it is dirty, and (1) no cracks or breaks occur on the adhesive surface, which is very advantageous when applied industrially.

〔Example〕

The content of the present invention will be illustrated below with preferred examples, but the present invention is not limited to these examples unless otherwise specified.

Comparative Example 1 Between two disk substrates each having a diameter of 130 ffil and made of an ethylene/tetracyclododecene copolymer, a disk made of the same kind of polymer as the substrates has an outer diameter of 130 mm, an inner diameter of 125 mm, and a thickness of approximately 0.0 mm. An outer circumferential spacer of /l ratio and an inner circumferential spacer with an outer diameter of 3 Gl1 m, a dowel line of 15 mm, and a thickness of about Q, 4++* were inserted, and they were simultaneously exposed to ultrasonic waves /8 under the conditions shown in Table 1. In all cases, the welded parts were defective, damaging Record 1-1 and making it unusable as an information recording substrate.

Details of the results are shown in Table 1.

Example 1 Using the same disk substrate and spacer as in the comparative example, the outer circumferential spacer and one disk substrate were first ultrasonically welded under the conditions shown in Table 2, and then the outer circumferential spacer was welded via the inner circumferential spacer. The welded disk substrate and the remaining one disk substrate are joined together, and the joint of the inner circumferential spacer is collectively ultrasonically welded. After that, the unwelded joint of the outer circumferential spacer and one disk substrate is ultrasonically welded. ■Welded. As a result, an information recording board with clean welded areas and high weld strength was obtained.

Example 2 The same procedure as in Example 1 was carried out except that polymethylmethacrylate-1 was used as the material for the disk substrate and spacer. As a result, a good information recording substrate was obtained.

[Brief explanation of drawings]

1 to 3 are diagrams showing the manufacturing method of the present invention. Fourth
The figure is a sectional view of an information recording substrate, and FIG. 5 is a diagram showing a conventional manufacturing method. 1.2... ・Disc base (anti-3...outer circumference spacer 4...inner circumference spacer 11...ultrasonic bone

Claims (1)

[Claims] In a method for manufacturing an information recording board with an air sandwich structure in which two disk substrates are ultrasonically welded via an outer circumferential spacer and an inner circumferential spacer, the outer circumferential spacer and one disk substrate are first welded. , the joint surfaces of the disk substrate to which the inner spacer and the outer spacer are welded and the opposing disk substrate are simultaneously welded from one direction, and then the unwelded portions of the outer spacer and the disk substrate are welded. A method for manufacturing an information recording substrate.