JPH05266513A - Optical disk and its production - Google Patents

Abstract

PURPOSE:To form a recording and reproducing layer in an adequate form and to eliminate the problem by liquid sagging of a monomer for forming a protective layer of the optical disk formed with the recording and reproducing layer and the protective layer by spin coating. CONSTITUTION:A monomer of an acrylic resin having the nature to repel an org. dyestuff soln. is applied by spin coating on the laser beam incident surface 2 of a polycarbonate substrate 11 and after only the monomer liquid sag at the end face of the outer periphery of the substrate is wiped away the coating is cured to form a hard coat 3. The cyanine dyestuff soln. is then applied by spin coating on the surface 1 formed with the recording and reproducing layer and a reflection layer 5 of gold is provided atop this recording and reproducing layer 4. The monomer of the acrylic resin is then applied by the spin coating and after the monomer liquid sag on the outer peripheral surface of the substrate is wiped away by a roller, the coating is cured to form a top coat 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk having a recording / reproducing layer on one surface and a laser light incident surface on the other surface, and a method for manufacturing the same.

[0002]

2. Description of the Related Art As an optical disc, a groove (guide groove) is formed on one side of a substrate to form a recording / reproducing layer forming surface, and an organic dye solution is applied to the recording / reproducing layer to provide a recording / reproducing layer. It is known that a reflective layer is provided on the reflective layer, and a protective film made of a hard synthetic resin is provided on the upper surface of the reflective layer and the other surface side of the substrate, that is, the laser light incident surface side.

In the above optical disk, the protective film and the recording / reproducing layer are generally formed by spin coating. For example, the protective film on the laser light incident surface side is as shown in FIG.
A groove of a groove 1a is formed on one surface to form a recording / reproducing layer forming surface 1 and the other surface is a laser light incident surface 2, and a hard synthetic resin monomer is dropped onto the substrate 11 while rotating at a low speed.
Is rotated at a high speed to shake off the monomer to form a film having a thickness of several μm, and then the monomer is polymerized and cured by ultraviolet rays, electron beams, or by heating to form a protective film (hard coat) 3 of an organic polymer. Has been formed.

[0004]

However, when the above-mentioned monomer is shaken off, it flows to the outer peripheral surface of the substrate 11 and a dripping 41 is generated as shown in FIG. This dripping 41 not only causes the center of gravity of the optical disc to be deviated, but when the dripping 41 is left as it is to cure the monomer, this portion is peeled off later to impair the appearance of the optical disc product or to be peeled off. It tends to result in being accompanied by optical disc products. In particular, when a solvent-containing monomer is used, air bubbles are generated in the dripping portion 41 when the monomer is hardened, and the air bubbles are broken after the hardening and the appearance of the optical disk product is remarkably deteriorated.

Therefore, conventionally, the end surface treatment for removing the hardened material in the dripping portion 41 by means such as cutting and finishing the outer peripheral surface has been carried out, but the work is troublesome and the cutting waste is caused by static electricity. There is a problem in that the work of removing the cutting dust that adheres is troublesome.

When a substrate is spin-coated with an organic dye solution in the same manner as described above to form a recording / reproducing layer, the coating liquid exceeds the outer peripheral surface of the substrate 11 and the laser light incident surface is exceeded. When the coating liquid wraps around to the outer peripheral portion of No. 2 and wraps around the coating liquid, the recording and reproducing function of the optical disc is impaired if the coating liquid is left as it is.

Therefore, conventionally, the surrounding portion 42 is removed by washing with an organic solvent, or a film forming process of a hard coat is carried out after application of an organic dye solution, and at that time, a monomer for the hard coat is washed. Although the methods have been adopted, all of them have problems that the work is troublesome, the cost of the optical disk increases due to the use of the cleaning organic solvent, and it is difficult to recover and reuse the monomer after cleaning. ..

The present invention has been made in view of the above problems, and a first object of the present invention is to provide an optical disc in which a recording / reproducing layer is formed by spin coating with an organic dye solution, and thus a defect in the sectional structure of the recording / reproducing layer is provided. Another object of the present invention is to provide an optical disc that has no errors during recording and reproduction and has no defect in appearance. A second object of the present invention is to provide a method for manufacturing an optical disc in which a protective film is formed by spin coating, which can solve the problems associated with the dripping of a monomer for forming the protective film. Especially. Further, a third object of the present invention is to provide a method for manufacturing an optical disc in which the recording / reproducing layer is formed by spin coating of an organic dye solution, which can prevent the organic dye solution from wrapping around.

[0009]

An optical disk according to claim 1 is provided with a protective film made of a hard synthetic resin on a laser light incident surface of a substrate having one surface as a recording / reproducing layer forming surface and the other surface as a laser light incident surface. In the optical disc, the protective film is provided on the outer peripheral end surface of the substrate and the non-groove area on the recording / reproducing layer forming surface, and the protective film is a hard synthetic resin having a property of repelling the organic dye solution forming the recording / reproducing layer. It is characterized by being formed by.

According to a second aspect of the present invention, there is provided a method for manufacturing an optical disk, wherein a laser light incident surface or a recording / reproducing layer forming surface of a substrate, one surface of which is a recording / reproducing layer forming surface and the other surface is a laser light incident surface, is protected by a hard synthetic resin. In the method of manufacturing an optical disc provided with a film, a substrate of the hard synthetic resin is spin-coated on the substrate surface, the monomer dripping on the outer peripheral edge of the substrate is wiped, and then the monomer on the substrate surface is polymerized and cured to form a protective film. It is characterized by doing.

According to a third aspect of the present invention, in the optical disc manufacturing method, when the recording / reproducing layer is formed by applying an organic solvent solution of an organic dye on the recording / reproducing layer forming surface, the organic dye solution is repelled on the laser light incident surface. The organic dye solution is spin-coated after forming a protective film having properties.

In the optical disc of the first aspect and the method of producing the optical disc of the third aspect, the combination of the resin for forming the substrate and the resin for forming the protective film is not particularly limited. It is important that the resin for forming the protective film has a lower wettability with respect to the organic dye solution than the resin for forming the substrate. Examples of the combination of such materials include a combination of a polycarbonate resin substrate and an acrylic resin protective film, a polycarbonate resin substrate and a silicone resin protective film, and a combination of a polymethylmethacrylate resin substrate and a fluororesin protective film. In the optical disc manufacturing method according to claim 2, it is not essential that the protective film has a property of repelling the organic dye solution,
Such a thing is preferable.

In the method of manufacturing an optical disk according to a third aspect of the present invention, the monomer liquid dripping on the outer peripheral surface of the substrate is a non-groove area (outer peripheral mirror portion) on the outer peripheral surface of the substrate and the recording / reproducing layer forming surface.
It is important to wipe it so that it stretches to the outside.
In the method of manufacturing the optical disc described in the above item 1, the dripping may be completely wiped off if desired.

The organic solvent solution of the organic dye for forming the recording / reproducing layer can be appropriately selected from those conventionally used and used.

[0015]

In the optical disc according to claim 1, the organic dye solution is properly applied to the groove area of the recording / reproducing layer forming surface without wrapping around to the laser beam incident surface side of the substrate. The cross-sectional structure of is good, and recording and reproduction can be performed accurately.

In the method of manufacturing an optical disk according to the second aspect, the monomer dripping on the outer peripheral surface of the substrate is wiped at the time of spin coating, and then the monomer on the surface of the substrate is polymerized and cured. The non-groove region (peripheral mirror portion) on the outer peripheral surface of the substrate and the surface on which the recording / reproducing layer is formed is thinly stretched and applied, and the adhesion of the protective film to the substrate surface is increased, so that it will not be peeled off later.

In the method of manufacturing an optical disk according to a third aspect of the present invention, a monomer for forming a protective film having a property of repelling an organic dye solution is spin-coated on the laser light incident surface of the substrate, and the monomer dripped on the outer peripheral surface of the substrate. Since the monomer is cured and then the organic dye is spin-coated, the recording / reproducing layer is formed after the protective film is formed in the non-groove area of the recording / reproducing layer forming surface. (By wiping, a part of the monomer is thinly spread and applied to the non-groove region), and the organic dye solution does not wrap around to the laser light incident surface side during the spin coating.

[0018]

Embodiments of the present invention will now be described with reference to the drawings. Example 1 A spiral groove 1a is provided on one surface to form a recording / reproducing layer forming surface 1, and the other surface is finished into a flat surface to form a laser light incident surface 2
A polycarbonate substrate 11 having a diameter of 120 mm and a thickness of 1.2 mm is prepared (FIG. 1A). This board 1
Acrylic resin monomer TB3 on the laser light incident surface 2 of 1
About 070 (manufactured by ThreeBond Co., Ltd.) by spin coating
The substrate outer peripheral surface 2 is coated with a thickness of μm, and the liquid dripping portion (see FIG. 2) on the outer peripheral surface of the substrate 11 is wiped with a roller 31.
1 and the non-groove area 22 of the recording / reproducing layer forming surface 1 (FIG. 1B), the monomer is polymerized and cured by irradiation of ultraviolet rays to provide a hard coat (protective film) 3. The acrylic resin has a property of repelling an organic solvent solution of an organic dye described later.

Next, a 3% isopropyl alcohol solution of a cyanine dye is spin-coated on the recording / reproducing layer forming surface 1 to provide a recording / reproducing layer 4 (FIG. 1 (c)), and then on the upper surface of this recording / reproducing layer 4. Film thickness of 1 by DC magnetron sputtering
A reflection layer 5 of 000Å of gold (Au) is provided (see FIG. 1).
(D)). Further, a top coat 6 having a film thickness of about 5 μm is provided on the upper surface of the reflective layer 5 in the same manner using the same monomer for forming the hard coat 3 (FIG. 1 (e)). In this case, the liquid dripping portion on the outer peripheral surface of the substrate 11 is similarly stretched by the roller 31.

The acrylic resin has a lower wettability with respect to the organic solvent (isopropyl alcohol, butyl cellosolve, cyclohexane, diacetone alcohol, etc.) used for coating the organic dye than that of the polycarbonate resin with respect to these organic solvents. Therefore, it repels the organic solvent solution of the organic dye.

The sectional structure of the optical disk thus manufactured is as shown in FIG. 1 (e). In the step of forming the hard coat 3 (FIG. 1 (b)), the liquid dripping portion of the monomer is changed to the outer peripheral end surface of the substrate. 21 and the non-groove region 22 are thinned and stretched, so that there is no concern that they will be peeled off later, and the hard coat of the non-groove region 22 repels this during spin coating of the organic dye solution. There is no trouble going around to the 2nd side.
Since the top coat 6 is also stretched in the same manner, it is not peeled off later. Therefore, this optical disc has an excellent recording / reproducing function and does not cause peeling of the hard coat and the top coat, resulting in a good appearance.

[0022]

As described above, in the optical disc of the first aspect, since the recording / reproducing layer of the organic dye is properly formed, there is an effect that the optical disc has excellent recording / reproducing characteristics. Further, according to the optical disc manufacturing method of the second aspect, the dripping that occurs when the protective film-forming monomer is spin-coated is thinly spread on the surface of the substrate and polymerized and cured. Therefore, the protective film is peeled off from the substrate later. There is an effect of not doing. Furthermore, according to the optical disc manufacturing method of claim 3, since the spin-coated organic dye solution is repelled by the protective film in the non-groove region of the recording / reproducing layer forming surface, the organic dye solution is irradiated onto the laser beam incident surface. It is possible to manufacture an optical disc having excellent recording / reproducing characteristics at low cost, since the recording / reproducing layer is properly formed without wrapping around to the side.

[Brief description of drawings]

FIG. 1 is a process explanatory view showing an embodiment of an optical disc manufacturing method according to the present invention, in which (a) is a cross-sectional view of a substrate on which a groove for forming a recording / reproducing layer is formed, and (b) is a hard coat forming process. (C) shows a recording / reproducing layer forming step, (d) shows a reflecting layer forming step, (e) shows a topcoat forming step, and a sectional structure of a finished optical disc, respectively.

FIG. 2 is an explanatory diagram showing a problem of a conventional optical disc manufacturing method.

FIG. 3 is an explanatory diagram showing another problem of the conventional optical disc manufacturing method.

[Explanation of symbols]

 1 Recording / Reproducing Layer Forming Surface 1a Groove 2 Laser Light Incident Surface 3 Hard Coat 4 Recording / Reproducing Layer 5 Reflective Layer 6 Top Coat 11 Substrate 21 Peripheral Edge Surface 22 Non-Groove Area 31 Roller 41 Drip 42 Wrap

Claims (3)

[Claims] 1. An optical disc having a protective film made of a hard synthetic resin on a laser light incident surface of a substrate, one surface of which is a recording / reproducing layer forming surface and the other surface of which is a laser light incident surface. And an optical disc in which the protective film is formed in a non-groove region on the recording / reproducing layer forming surface and is made of a hard synthetic resin having a property of repelling the organic dye solution forming the recording / reproducing layer. 2. A method of manufacturing an optical disc, wherein a protective film made of a hard synthetic resin is provided on a laser light incident surface or a recording / reproducing layer forming surface of a substrate having a recording / reproducing layer forming surface on one side and a laser beam incident surface on the other side. A method for manufacturing an optical disk, characterized in that the substrate of the hard synthetic resin is spin-coated on the substrate surface, the monomer dripping on the outer peripheral edge surface of the substrate is wiped, and then the monomer on the substrate surface is polymerized and cured to form a protective film. .. 3. When a recording / reproducing layer is formed by applying an organic solvent solution of an organic dye on the recording / reproducing layer forming surface, a protective film having a property of repelling the organic dye solution is formed on a laser beam incident surface. The method for producing an optical disk according to claim 2, wherein the organic dye solution is spin-coated.