JP3230701B2 - recoding media - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium, and is suitably applied to, for example, a recordable optical disk.

[0002]

2. Description of the Related Art Conventionally, as a recordable optical disc, for example, a magneto-optical disc or a write-once optical disc, it is necessary to form a pregroove or a prepit with high precision. Is used. In practice, this type of optical disk is obtained by polishing a glass disk and applying a photoresist, and then exposing the photoresist by irradiating the glass substrate with a laser beam. Thereafter, by developing the glass substrate, pits having irregularities are formed on the glass substrate.

In an optical disk having pits and grooves formed on a glass substrate, a resin substrate having the same diameter as the glass substrate is attached to the back surface of the glass substrate to increase the strength of the glass substrate. It has been made larger.

[0004]

However, in this type of recording medium, the strength in the surface direction of the glass base is ensured by the above-mentioned resin base, but the strength of the circumferential end face of the disk is still insufficient. Problem. That is, in the case of this type of optical disc, there is a possibility that the circumferential end face is damaged when the optical disc is dropped, for example.

The present invention has been made in view of the above points, and it is an object of the present invention to propose a recording medium capable of avoiding damage to a glass substrate.

[0006]

According to the present invention, there is provided a disk-shaped recording medium 1 comprising a disk-shaped glass substrate 2 and a disk-shaped resin substrate 5 adhered thereto. The diameter is made larger than the glass substrate 2. Further, in the present invention, the glass substrate 2 is attached to one surface of the resin substrate 5. Further, in the present invention, the first glass substrate 13 is adhered to one surface of the resin substrate 11 and the second glass substrate 14 is adhered to the other surface of the resin substrate 11.

[0007]

In the disk-shaped recording medium 1 in which the disc-shaped resin base 5 is adhered to the disc-shaped glass base 2, if the diameter of the resin base 5 is made larger than the diameter of the glass base 2, the recording medium 1 is formed. When dropped, the resin base 5 protects the glass base 2, and as a result, damage to the glass base 2 can be avoided.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

In FIGS. 1 and 2, reference numeral 1 denotes an optical disk as a whole. A recording surface 3 made of a magnetic film is provided on the surface of a glass substrate 2 on which prepits and pregrooves are formed. Adhesive 4 on the back of
Thus, a resin base 5 having a larger diameter than the glass base 2 is adhered. As a result, in the optical disk 1, the resin substrate 5 is configured to partially protrude from the circumferential end surface of the glass substrate 2 in the radial direction.

Thus, when an impact is applied to the optical disk 1 from the circumferential end face of the optical disk 1 toward the center of the optical disk 1, the projecting portion of the resin substrate 5 absorbs the impact force and the glass substrate 2 Is designed to protect the circumferential end face. In the case of the embodiment, the resin base 5 has a molecular weight of 240.
It is made of 00 or more polycarbonate. Here, the optical disk 1 is housed in a predetermined cartridge 6 as shown in FIG. 3, so that the optical disk 1 prevents the glass substrate 2 and the recording surface 3 from being scratched or dusted by the cartridge 6. Has been prevented. That is, optical disk 1
In the above, the cartridge 6 is loaded into a recording and / or reproducing apparatus to record or reproduce information on the optical disk 1, and can be carried in a state of being stored in the cartridge 6.

As shown in FIG. 4, when the optical disk 1 is inclined obliquely from the horizontal direction in the cartridge 6, the glass substrate 2 and the resin substrate 5 are provided so that the glass substrate 2 does not hit the inner wall of the cartridge 6. If the radius difference between the glass substrate 2 and the resin substrate 5 is b and the deformation difference of the resin substrate 5 due to the impact is b, the radius difference A (FIG. 2) between the glass substrate 2 and the resin substrate 5 is

(Equation 1) Is selected. Thus, even when the optical disc 1 is tilted in the cartridge 6, the resin substrate 5 abuts on the inner wall of the cartridge 6, so that the circumferential end surface of the glass substrate 2 can be protected.

In the above configuration, for example, if the cartridge 6 is dropped while the optical disk 1 stored in the cartridge 6 is moving, the optical disk 1 collides with the inner wall of the cartridge 6, and the optical disk 1 is circular. Large impact force is given to the peripheral end surface. At this time, since the diameter of the resin substrate 5 of the optical disk 1 is larger than the diameter of the glass substrate 2, the circumferential end surface of the resin substrate 5 comes into contact with the inner wall of the cartridge 6. As a result, in the optical disk 1, the circumferential end surface of the glass substrate 2 is protected by the resin substrate 5,
Damage on the circumferential end surface of the glass substrate 2 can be avoided beforehand.

According to the above configuration, the disk-shaped recording medium 1 which can avoid the damage of the glass substrate 2 beforehand is realized by making the diameter of the resin substrate 5 larger than the diameter of the glass substrate 2. can do.

In the above-described embodiment, the optical disc 1 having the glass substrate 2 and the recording surface 3 provided on one side has been described. However, the present invention is not limited to this, and as shown in FIG. In the optical disk 10 having the first and second glass substrates 13 and 14 adhered to both surfaces of the optical disk 10 with a predetermined adhesive 12, the diameter of the resin substrate 11 is the same as that of the first and second glass substrates 13 and 14. If the diameter is larger than the diameter, the first and second glass substrates 1 are formed by the resin substrate 11.
The circumferential end faces of 3 and 14 can be protected.

In the above-described embodiment, the case where the optical disc 1 according to the present invention is housed in the cartridge 6 has been described. However, the present invention is not limited to this, and the above-described case is also applicable when the optical disc 1 is used alone. As in the case (1), the circumferential end surface of the optical disk 1 can be protected from impact. In this case, for example, when the optical disk 1 is moved, the outer peripheral portion where the resin base 5 protrudes is pinched by a finger.
The glass substrate 2 can be moved without directly touching the glass substrate 2, and damage to the glass substrate 2 can be avoided.

In the above-described embodiment, the present invention
The case where the present invention is applied to the recordable optical disc 1 on which the recording surface 3 is formed has been described. However, the present invention is not limited to this. The present invention can be applied to various optical disks provided with the glass substrate 2.

In the above-described embodiment, the case where the glass substrate 2 and the resin substrate 5 are adhered with a predetermined adhesive has been described. Various bonding methods can be applied. Further, in the above-described embodiment, the case where polycarbonate is used as the resin substrate 5 has been described, but the present invention is not limited to this, and various materials can be used as the resin substrate 5.

[0018]

As described above, according to the present invention, in a disk-shaped recording medium in which a disc-shaped resin base is adhered to a disc-shaped glass base, the diameter of the resin base is larger than the diameter of the glass base. Thus, when the recording medium is dropped, the glass substrate is protected by the resin substrate, and the glass substrate can be prevented from being damaged.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of an optical disk according to the present invention.

FIG. 2 is a sectional view of the optical disk shown in FIG. 1;

FIG. 3 is a sectional view showing the optical disk of FIG. 1 housed in a cartridge;

FIG. 4 is a cross-sectional view showing a contact state between a circumferential end surface of an optical disc and an inner wall of a cartridge according to the present invention.

FIG. 5 is a sectional view of an optical disc according to another embodiment.

[Explanation of symbols]

1, 10 optical disk, 2, 13, 14 glass substrate, 3, 15, 16 recording surface, 4, 12 adhesive,
5, 11 ... resin base.

Claims (3)

(57) [Claims] 1. A disk-shaped recording medium comprising a disc-shaped resin base adhered to a disc-shaped glass base, wherein the resin base has a larger diameter than the glass base. recoding media. 2. The recording medium according to claim 1, wherein said glass substrate is adhered to one surface of said resin substrate. 3. The method according to claim 1, wherein a first glass substrate is adhered to one surface of the resin substrate, and a second glass substrate is adhered to the other surface of the resin substrate. The recording medium according to the above.