JPS62137750A - Production of information recording medium - Google Patents

Abstract

PURPOSE:To secure the complete junction with no difference caused between the upper and lower sides by performing the junction between a disk substrate and a spacer by means of the ultrasonic horns set at both sides and the ultrasonic welding process carried out at the both sides of the disk substrate. CONSTITUTION:The plastic substrates 2A and 2B are fitted to the rings 3 and 4 and set between the ultrasonic horns 12 and 13 of an ultrasonic welding machine. Then the pressure is applied from both sides of the substrates 2A and 2B and at the same time the ultrasonic waves are oscillated through both horns 12 and 13 for execution of the ultrasonic welding. Thus the frictional heat is concentrated at the parts of projections 8 and 9 of the rings 3 and 4. Then both projections 8 and 9 are melted and the substrates 2A and 2B are put together with both rings 3 and 4 at the inner and outer circumferences of these rings. Thus no difference of adhesion is produced between the substrates 2A and 2B to secure the complete adhesion since the ultrasonic welding is performed by both horns 12 and 13 and at both sides of both substrates 2A and 2B respectively.

Description

[Detailed description of the invention] Technical field .

The present invention relates to a method of manufacturing a plastic information recording medium, such as an optical disk, on which 4F7 information is written and read using, for example, a laser beam.

Conventional technology-i is a disk-shaped disk substrate used for optical disks, optical memories, etc., in which a thin film recording layer is formed on the surface of a transparent plastic material, such as acrylic resin, in order to transmit optical signals. An air sandwich structure is adopted in which the recording layers face each other and are joined to each other at the inner and outer peripheral edges so that a hollow portion is formed between the recording layers. Such an air sandwich structure has the advantage that the recording layer is shielded from the outside, so there is no damage or scratches caused by carelessness during handling, and there is no adhesion of dust.

In the case of such an air sandwich type, it is common to use an ultraviolet curable adhesive or a thermosetting adhesive as shown in Japanese Patent Laid-Open No. 60-43242, or a thermosetting adhesive. However, when using these adhesives, the number of steps is large and the cost is high. Further, dust may be mixed in during sealing, and adhesion failure may occur, resulting in a high defect rate.

In this regard, JP-A-60-103537 and JP-A-60
As shown in Publication No. 113346, two disk substrates with a spacer interposed between them are set on the base of an ultrasonic welding machine, and an ultrasonic horn is placed on one disk substrate to apply pressure and apply ultrasonic welding. Some methods employ an ultrasonic welding method in which welding is performed by oscillating sound waves. However, in the systems disclosed in these publications, there is a difference in bonding conditions such as strength and bonding margin between the upper and lower portions of the spacer. In particular, when the two upper and lower disk substrates are made of different materials, there is a problem in that it may not be possible to properly bond one side of the disk substrates.

Purpose The present invention has been made in view of the above points, and is an information recording method that can shorten the time required for the sealing process of an air sandwich structure, as well as ensure reliable bonding and reduce the defective rate. An object of the present invention is to provide a method for manufacturing a medium.

Structure: In order to achieve the above object, the present invention provides two disk substrates each having a recording layer on which information is optically recorded and reproduced, with the recording layer side being the inner side, and the inner and outer peripheries of the recording layer side being the inner side. A method for manufacturing an air sandwich type information recording medium in which a ring-shaped spacer having concave portions and protrusions corresponding to the concave portions is interposed between the disk substrates, the spacer and the disk substrate being interposed between the disk substrates. It is characterized by ultrasonic welding from both sides using ultrasonic horns provided on both sides.

Hereinafter, one embodiment of the present invention will be described based on the drawings. First, the information recording medium 1 of this embodiment has two parts as shown in FIG.
Plastic substrates 2A and 2B as disk substrates
It is of an air sandwich type, consisting of an inner circumferential ring 3 and an outer circumferential ring 4 as spacers. Here, the plastic substrates 2A and 2B are disk-shaped formed by injection or compression, and coated with a dye, and have a group surface 5 as a recording layer formed on the negative surface thereof. Then, the plastic substrate 2A is positioned on the group surface 5 side.

2B has an inner circumferential recess 6 and an outer circumferential recess 7 inside the group surface 5.
are formed in concentric circles. In the air sandwich structure described above, these group surfaces 5 are arranged so as to face each other on the inside.

Further, the inner ring 3 and the outer ring 4 are molded from the same material as the plastic substrates 2A and 2B, and the inner ring 3 has protrusions 8 formed on both sides to be fitted into the inner recess 6, and the outer ring Protrusions 9 that are fitted into the outer peripheral recess 7 are formed on both sides of the ring 4. Here, the diameter of the center hole IO of the inner ring 3 is the plastic substrate 2A,
The diameter is the same as that of the center hole 11 of 2B. Further, the outer diameter of the outer ring 4 is the same as the outer diameter of the plastic substrates 2A and 2B.

The information recording medium 1 will be manufactured using these members. First, the inner circumferential ring 3 is placed on the plastic substrate 2B, and its protrusion 8 is fitted into the inner circumferential recess 6. Similarly, the projections 9 of the outer ring 4 are fitted into the outer recess 7. Place the plastic substrate 2A on top of it,
The inner circumferential recess 6 and outer circumferential recess 7 are fitted into the protrusions 8 and 9 of the inner circumferential ring 3 and outer circumferential ring 4, respectively, and set so that there is no play. Here, the fitting portions between the inner circumferential recess 6 and the protrusion 88 and the outer circumferential recess 7 and the protrusion 9 are to be ultrasonic welded portions, which will be described later, and are shaped so that they fit with a slight gap left. , the dimensions are set.

Therefore, in this fitted state, the plastic substrates 2A and 2B are automatically centered.

However, in this way, the plastic substrates 2A, 2B
The fitted rings 3 and 4 are set between the ultrasonic horns 12 and 13 of an ultrasonic welding machine, as shown in FIG. Then, pressure is applied from both sides of the plastic substrates 2A and 2B, and the ultrasonic horns 12 and 13 are caused to oscillate ultrasonic waves to perform ultrasonic welding. At this time, frictional heat concentrates on the protrusions 8.9 of the rings 3, 4 and melts the protrusions 8, 9, thereby joining the plastic substrates 2A, 2B at the inner and outer peripheries. At this time, in this embodiment, ultrasonic welding is performed from both sides of the plastic substrates 2A and 2B using the ultrasonic horn 12.13, so there is no difference in the adhesion status between the plastic substrate 2A side and the plastic substrate 2B side. Be sure to adhere. This ensures that the substrates 2A and 2B are bonded even if they are made of different materials. As a result, the defective rate will decrease.

Effects In the present invention, as mentioned above, in the air sandwich type, the disk substrate and the spacer are joined by ultrasonic welding from both sides of the disk substrate using ultrasonic horns provided on both sides. It is possible to perform reliable joining without causing any difference between the upper and lower sides, and the defective rate can be reduced.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; Fig. 1 is a cross-sectional view during ultrasonic welding, Fig. 2 is a cross-sectional view of each member, Fig. 3 is a plan view of the plastic substrate, and Fig. 4 is a cross-sectional view of the inside. A plan view of the circumferential ring, FIG. 5 is a plan view of the outer circumferential ring. 2A, 2B...Plastic board (disc board),
3... Inner ring (spacer), 4... Outer ring (spacer), 5... Group surface (recording layer), 6°7
... recess, 8, 9... protrusion, 12.13... ultrasonic horn

Claims (1)

[Claims] Two disk substrates each having a recording layer on which information is optically recorded and reproduced, with the recording layer side facing inside, and having recesses on the inner and outer peripheries of the recording layer side and protrusions corresponding to these recesses. In the method for manufacturing an air sandwich type information recording medium in which a ring-shaped spacer is interposed between the disk substrates, the spacer and the disk substrate are ultrasonically welded from both sides using an ultrasonic horn provided on both sides of these disk substrates. A method for manufacturing an information recording medium, characterized by: