KR19990034081A - Optical disc and mold for manufacturing optical disc - Google Patents

Abstract

The present invention relates to an optical disc having predetermined information by a plurality of information feet and an optical disc manufacturing mold for manufacturing the optical disc.

According to the present invention, the thickness of the optical disk is gradually thickened from the outer portion to the center portion, so that the resin fluidity of the molten resin increases when the resin is injected into the cavity of the manufacturing mold for forming the optical disk. Not only the uniform strength can be obtained, but also the desired resin density can be maintained up to the outer portion so that the complete shape of the information feet can be easily obtained.

Description

Optical disc and its optical disc manufacturing mold

The present invention relates to an optical disc having predetermined information by a plurality of information feet and an optical disc manufacturing mold for manufacturing the optical disc.

An optical disk such as a compact disk (CD) or a digital versertile disk (DVD) or the like has a plurality of information feet 11 inserted in a predetermined depth with respect to one side as schematically shown in FIG. The optical disc 10 has predetermined information by the pattern of the information pits 11, and the information can be reproduced through the laser beam irradiated by the optical pickup unit in the optical disc reproducing apparatus.

The above-described optical disc 10 may be injection molded in the optical disc manufacturing mold 20 as shown in FIG. 2, for example. The optical disc manufacturing mold 20 includes a first mold 21 fixed in a molding apparatus (not shown) and a second mold 22 installed to be accessible and spaced apart from the first mold 21. . The first mold 21 is provided with a stamper 211 having fine protrusions (not shown) for forming the information feet 11 of the optical disk 10 described above. When the second mold 22 approaches the first mold 21 and the second mold 22 is in close contact with the stamper 211, the stamper of the second mold 22 and the first mold 21 may be used. A cavity 23 in which the optical disc 10 is to be formed is formed between the 211. The first mold 21 is provided with a sprue 212 for introducing the resin into the cavity 23, the sprue 212 is a stamper of the second mold 22 and the first mold 21. The gate 24 formed by the close contact of 211 communicates with the cavity 23.

As shown in FIG. 2, when molten resin is injected into the cavity 23 through the sprue 212 and the gate 24 while the first mold 21 and the second mold 22 are in close contact, The injected molten resin is filled in the cavity 23, and after a predetermined time, the resin is cured. After the resin in the cavity 23 is cured, the second mold 22 is separated from the first mold 21 to separate the cured resin 15 from the manufacturing mold 20 as shown in FIG. 3. The optical disc 10 is obtained by separating the cured resin 19 in the gate 24 from the resin 15 cured in the cavity 23, as shown in FIG. It has the same information pits as the protrusions formed on the stamper 212 of the first mold 21.

On the other hand, when the resin is injected into the cavity 23 of the manufacturing mold 20 for molding the optical disk 10 as described above, the resin is quickly cured in the middle of the molten resin flowing in the cavity 23, It is necessary to ensure uniform filling in the inside.

By the way, conventional optical discs are not only thin in thickness, but the thickness (vertical distance between both sides) is set equal to each other in each part of the optical disc. Therefore, the fluidity of the resin in the cavity in the manufacturing mold is not good, and even if the resin is not completely filled or filled in the outer portion of the cavity, the resin density at the site is lowered, so that the desired mechanical strength or the shape of the information feet can be reduced. A case is not obtained. In addition, in order to improve recording density, an optical disc having a thickness thinner than that of a conventional 1.2 mm thick optical disc, that is, an optical disc having a thickness of 0.6 mm, has been produced. The problem described above becomes more prominent.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides an optical disk having an improved structure such that the strength at the outer portion thereof is improved at the time of manufacture and the shape of the information feet of the outer portion can be more reliably performed. There is a purpose.

It is another object of the present invention to provide an optical disk manufacturing mold for manufacturing an optical disk having an improved structure so that the strength of the outer portion can be improved and the shape implementation of the information feet on the outer portion can be more reliably performed.

1 is a schematic perspective view of a conventional optical disk,

FIG. 2 is a schematic cross-sectional view of a manufacturing mold for manufacturing the optical disc shown in FIG. 1;

3 is a schematic cross-sectional view of a state in which the first mold and the second mold shown in FIG. 2 are separated;

4 is a schematic view for explaining a process of obtaining an optical disc by the manufacturing mold shown in FIG.

5 is a schematic perspective view of an optical disk according to an embodiment of the present invention;

FIG. 6 is a schematic sectional view taken along line VI-VI of the optical disc shown in FIG. 5;

FIG. 7 is a schematic separated cross-sectional view of a manufacturing mold for manufacturing the optical disc shown in FIG. 5;

8 is a schematic cross-sectional view of the manufacturing mold shown in FIG.

<Description of Symbols for Main Parts of Drawings>

30 ... optical disc 31 ... information feet

40.Optical disc manufacturing mold 41 ... 1st mold

411 ... stamp 42 ... second mold

43 ... cavity

In order to achieve the above object, the optical disc according to the present invention is characterized in that the disc has a predetermined amount of information by a plurality of information feet, and the thickness gradually increases from the outer side to the center.

In order to achieve the latter object, an optical disk manufacturing mold according to the present invention has a cavity corresponding to the information disk for forming a disk-shaped optical disk having predetermined information by a plurality of information feet. It is characterized by a gradual increase in thickness from the outside to the center.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 5 is a schematic perspective view of an optical disk according to an embodiment of the present invention, and FIG. 6 is a schematic sectional view taken along line VI-VI of the disk shown in FIG.

Referring to the drawings, the optical disc 30 of the present embodiment has predetermined information in a pattern of a plurality of information pits 31 inserted in a predetermined depth with respect to one side, like the optical disc 10 described with reference to FIG. 1. The information can be reproduced through a laser beam irradiated by an optical pickup (not shown) in the optical disc reproducing apparatus.

On the other hand, unlike the conventional optical disk 10, the optical disk 30 of the present embodiment is formed such that the thickness d1 of the outer portion is smaller than the thickness d2 of the central portion, and the thickness gradually increases from the outer portion to the central portion. This is a feature of the present invention. At this time, it is preferable that the surface on which the information pits are written form a plane and the thickness thereof is changed by inclining the opposite surface so that deformation of the information pits is suppressed.

The above-mentioned thicknesses d1 and d2 may be set in consideration of the overall thickness of the optical disc. For example, for an optical disc having an overall thickness of 0.6 mm, the thickness d1 of the outer portion may be about 50 μm smaller than 0.6 mm and the center portion may be set. It is preferable to set the thickness d2 of about 50 micrometers larger than 0.6 mm.

The above-described optical disc 30 may be manufactured by, for example, an optical disc manufacturing mold 40 as shown in FIGS. 7 and 8. This manufacturing mold 40, like the conventional optical disc manufacturing mold 20 described with reference to FIG. 2, is fixed in a molding apparatus (not shown) and has fine protrusions for the formation of the information feet 31 (see FIG. 5). A first mold 41 to which the stamper 411 is fixed, and a second mold 42 provided to be accessible and spaced apart from the first mold 41. When the second mold 42 approaches the first mold 41 and comes into close contact with the stamper 411, the second mold 42 is disposed between the second mold 42 and the stamper 411 of the first mold 41. A cavity 43 in which the optical disc 30 is to be formed is formed. The first mold 41 is provided with a sprue 412 for introducing the resin into the cavity 43, the sprue 412 is in close contact with the first mold 41 and the second mold 42. It communicates with the cavity 43 by the gate 44 formed by it.

On the other hand, in the optical disk manufacturing mold 40 of the present embodiment, the stamper 411 of the first mold 41 forming the cavity 43 together with the second mold 42 is generally planar, and the second mold 42 ) Is inclined away from the stamper 411 of the first mold 41 toward the center of the cavity 43 from the outer portion of the cavity 43. Therefore, the cavity 43 has a thickness D1 of the outer portion smaller than the thickness D2 of the central portion, and gradually increases in thickness from the outer portion to the central portion.

The process of obtaining the optical disc 30 using the optical disc manufacturing mold 40 is not different from the process of obtaining the conventional optical disc 10 by the conventional optical disc manufacturing mold 20. That is, as shown in FIG. 8, the resin is injected into the cavity 43 through the sprue 412 and the gate 44 while the first mold 41 and the second mold 42 are in close contact with each other. After the predetermined time has elapsed and the resin is cured, the second mold 42 is separated from the first mold 41 to separate the cured resin from the manufacturing mold, and then the gate 44 is removed from the cured resin in the cavity 43. When the cured resin is separated inside the optical fiber, the optical disk having the same shape as the cavity 43, that is, the optical disk 30 of the present embodiment is obtained. The optical disc 30 has information pits 31 having the same pattern as the protrusions formed on the stamper 411 of the first mold 41.

On the other hand, in the optical disk manufacturing mold 40 of the present embodiment, as described above, the thickness of the cavity 43 having a shape corresponding to the optical disk 30 for forming the optical disk has a central portion from the outside of the cavity 43. Since it is formed to gradually become thicker, when the resin is injected into the cavity 43 of the manufacturing mold 40 for forming the optical disk 30, the resin of the molten resin than in the conventional manufacturing mold 20 Excellent fluidity Therefore, since the molten resin can be quickly and reliably filled in the cavity 43 to the outer portion, the optical disc 30 manufactured by the manufacturing mold 40 can obtain uniform strength to the outer portion. In addition, the desired resin density can be maintained up to the outer portion so that the complete shape of the information feet can be easily obtained. According to the present invention, for example, in the thin optical disk having an overall thickness of 0.6 mm and the manufacturing mold of the optical disk, the above-described effects are more pronounced.

As described above, according to the present invention, the optical disk is gradually thickened from the outer portion to the center, so that the resin fluidity of the molten resin when the resin is injected into the cavity of the manufacturing mold for forming the optical disk. Since it is increased, not only uniform strength can be obtained up to the outer portion, but also the desired resin density can be maintained up to the outer portion so that the complete shape of the information feet can be easily obtained.

Claims (3)

In a disc shaped optical disc having predetermined information by a plurality of information feet, An optical disc, characterized in that the thickness gradually increases from the outside to the center. The method of claim 1, The thickness of the portion closest to the center thereof is greater than 0.6 mm, and the thickness of the portion furthest from the center is smaller than 0.6 mm. In the optical disk manufacturing mold having a cavity corresponding to the information disk for forming a disk-shaped optical disk having a predetermined information by a plurality of information feet, The cavity is an optical disk manufacturing mold, characterized in that the thickness gradually increases from the outer side to the center.