JPS63316332A - Optical disk - Google Patents

Abstract

PURPOSE:To prevent generation of microchipping by enclosing the outside circumference of a disk with annular frames to a U shape so that mechanical impact is dispersed. CONSTITUTION:This optical disk is constructed by joining a front substrate 1 on which a recording layer 3 is formed and a rear substrate 2 on which a recording layer 4 is formed by an adhesive agent 5, adhering the 1st L-shaped annular frame 8 to the end face of the disk and adhering another L-shaped annular frame 9 thereto from the other side. The L-shaped annular frame 9 is formed to the outside diameter larger than the outside diameter of the L- shaped annular frame 8 in order to enclose the outside circumference of the disk with these two frames 8, 9 to the U shape in the sectional shape. The adhesion of the frame 8 to the disk substrate may be executed simultaneously at the time of joining the front substrate 1 and the rear substrate 2 by an adhesive layer 5. The outside circumference of such optical disk is enclosed with the annular frames to the U shape. The impact is thus dispersed by the annular frames and the generation of microchipping to cause cracking is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to improving the impact resistance and weather resistance of original disks.

2. Description of the Related Art In recent years, original disk devices that can record information signals at high density have come into use. This method changes the reflectance of the recording medium by focusing a laser beam on the recording surface of the disk and making holes in the recording medium, or by changing the material structure of the recording medium with the heat of the laser beam, and reproduces information. The principle of obtaining is used. In addition, an alloy of rare earths and transition metals is used as the recording medium, and the direction of magnetization of the recording medium is reversed by heating it with a laser beam, and during playback, continuous laser light is irradiated with an optical intensity several times lower than that of recording. , Magneto-optical disks that utilize the fact that the Kerr rotation angle of reflected light changes depending on the direction of magnetization are also being actively developed. This magneto-optical disk has the feature that it can not only be used for recording and reproduction, but also for erasing. In addition, there are optical disks that utilize phase change to enable recording, reproduction, and erasing.

Several types of structures of these conventional optical discs have been considered. The structure will be explained below using the drawings. 4, 6, and 6 show cross sections of the outer periphery of conventional disk structures. 4, 6, and 6, 1 and 2 are front and back substrates, respectively, and 3 and 4 are recording layers formed on the front substrate 1 and the back substrate 2, respectively. However, in a double-sided disc, there is no difference between the front and back sides, while in a single-sided disc, one recording layer 4 is not required.

In the disk structure shown in FIG. 4, a front substrate 1 on which a recording layer 3 has been formed in advance and a back substrate 2 on which a recording layer 4 has been formed in advance are bonded together with an adhesive layer 6. 6th
The disk structure shown in the figure has a front substrate 1 and a back substrate 2 bonded to each other with a metal annular spacer 6 interposed therebetween. In the case of FIG. 6, there are cases where an adhesive is filled between the recording layers and cases where a gap is maintained. This conventional example shows a case where the void is maintained. Furthermore, the sixth
In the case shown, the annular spacer shown in FIG. 6 has a T-shaped cross section.

Problems to be Solved by the Invention However, optical disks having the above structure often use glass as a substrate material, and the recording film thereof generally has poor weather resistance. When glass or highly hard plastic is used for the substrate material, the handling of the disk is poor, and there is a problem in that the disk sometimes breaks when dropped from a desk, for example. On the other hand, the lifespan of a disk must be guaranteed for at least 10 years at normal temperature and normal humidity, but the recording film has the disadvantage of being particularly sensitive to humidity among its weather resistance. This problem is particularly noticeable in the case of magneto-optical disks.
This is due to the use of highly oxidizing rare earth elements in the recording medium.

To deal with these problems, in the structure shown in Figures 4 and 6, the end face of the disk is exposed, so if a mechanical impact is applied to the end face, a minute chip will occur on the end face, and the end face will be damaged. The drawback is that cracks occur over the entire surface of the disc. On the other hand, the one in Figure 6 uses an annular spacer 7 with a T-shaped cross section, so the end face is protected. Even if a spacer is used, it cannot be integrally molded using a press or the like, so it has the disadvantage that it is not suitable for mass production.

An object of the present invention is to provide an optical disk that prevents the disk from being destroyed even when the mechanical impact is applied to the end surface of the optical disk, and that has improved weather resistance, particularly moisture resistance.

Means for Solving the Problems In order to achieve this object, the optical disc of the present invention has an annular frame having an L-shaped cross section attached from the front and back sides of the optical disc, and the outer periphery of the disc is attached to the two L-shaped sections. It is constituted by means of surrounding it with an annular frame so that the cross-sectional shape is U-shaped.

With the above means, even if a mechanical shock is applied to the end face of the optical disc, since the outer periphery of the disc is surrounded by an annular frame in a U-shape, the mechanical shock is dispersed and there is no possibility of minute chips that may cause cracks. does not occur. In addition, since the end face is surrounded by a U-shaped cross-sectional shape, the intrusion of moisture from the end face is reduced.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings. 1, 2 and 3 are cross-sectional views of embodiments of the optical disc of the present invention. In FIG. 1, 1 is a front substrate of an optical disc, and 2 is a back substrate. Recording layers 3 and 4 are formed on each of these substrates, and in the case of FIGS. 1 and 2, the surface substrate 1 on which the recording layer 3 is formed is
and the back substrate 2 on which the recording layer 4 is formed are bonded together by an adhesive layer 6, and a first L-shaped annular frame 8 is attached to the end surface of the disk.
is glued together, and then another L-shaped annular frame 9 is glued from the other side.

In order to surround the outer periphery of the disk in a U-shaped cross section with these two L-shaped annular frames 8 and 9, the outer diameter of the L-shaped annular frame 9 is larger than the outer diameter of the L-shaped annular frame 8. It's getting bigger.

The L-shaped annular frame 8 is bonded to the disk substrate using an adhesive layer 6.
It may be performed at the same time when the front substrate 1 and the back substrate 2 are bonded together. Here, the difference between Figures 1 and 2 is the first
In the figure, the L-shaped annular frame 8.9 protrudes from the disk surface, whereas in FIG. It has the characteristic that it does not protrude. In the case of FIG. 3, the front substrate 1 and the back substrate 2 are bonded together via an annular spacer 6,
Thereafter, the outer periphery of the disk is surrounded by a U-shaped annular frame 8°9.

In the optical disc constructed as described above, the outer periphery of the disc is surrounded by an annular frame in a U-shape, so that mechanical shock is dispersed and minute chips that can cause cracks do not occur.

Furthermore, whereas what generally affects the weather resistance of a disk is the intrusion of moisture from the edge surface of the disk, in the optical disk of the present invention, the distance from the recording layer 3.4 along the inner wall of the disk substrate to the point where it is exposed to the outside air is By adding the above-mentioned annular frame, the amount will be increased substantially. In the case of a 6.26-inch disk, in the conventional structure, the distance from the recording layer 3.4 to the point where it touches the outside air is approximately 4 jLIL in Figure 4 and Figure 6.
, is about 6.5'' in the case of FIG. 6, whereas in the optical disc of the present invention, it is 7u or more, which significantly reduces moisture intrusion.

Effects of the Invention The present invention provides an annular frame with an L-shaped cross section that is viewed from the front and back sides of an optical disc, and the outer periphery of the disc is aligned with the two L-shaped sections.
By surrounding the optical disk with a U-shaped annular frame, even when a mechanical shock is applied to the end surface of the optical disk, the annular frame disperses the am and prevents the slightest amount of am from causing cracks. No chipping occurs. Furthermore, since the end face is surrounded by two L-shaped annular frames in a U-shaped cross-section, the intrusion of moisture from the end face is significantly reduced, making it possible to provide an optical disc with a long life. Furthermore, the means to surround the outer periphery of the disk in a U-shaped cross-section is achieved by combining two L-shaped annular frames, making it easy to attach to the disk. If it is made of metal such as aluminum, press processing is possible.
Industrially, this has the effect of being able to provide an optical disc that has both impact resistance and weather resistance at a low cost.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the structure of an optical disc in one embodiment of the present invention, FIGS. 2 and 3 are sectional views showing the structure of an optical disc in another embodiment of the invention, and FIGS. 4 and 6 ,
and FIG. 6 are cross-sectional views showing the structure of a conventional original disk. 1...Front board, 2...Back board, 3
．． 4...Recording layer, 6...Adhesive layer, 6.
...Annular spacer, 8゜9...L-shaped annular frame. /-11 Clothes surface board 8°''-I L-shaped f-shaped back A scale 9---O2 〃 Fig. 2 Fig. 4 Fig. 5 Fig. 6

Claims (1)

[Claims] An annular frame having an L-shaped cross-section is attached to the front and back surfaces of the optical disc, and the outer periphery of the disc is surrounded by the two L-shaped annular frames so that the cross-section has a U-shape. optical disk.