JPH07169119A - Production of optical disk - Google Patents

Abstract

PURPOSE:To prevent the damage and falling of a printed film with letters, symbols, a design drawing, etc., corresponding to the contents of information to be recorded in an optical disk. CONSTITUTION:A reflecting film 13 formed on the recording surface 12a of a disk substrate 12 is protected with a protective film 14. While the protective film 14 is in a semi-cured state, a toner or ink is embedded in the film 14 by an ink jetting system, etc., to print letters, symbols and a design drawing corresponding to the contents of information to be recorded and then the protective film 14 is perfectly cured. A printed film 15 is formed in the protective film 14 in one body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical disc capable of recording, reproducing or erasing digital signals such as a digital audio disc such as a compact disc, a video disc, a still image and a document file.

[0002]

2. Description of the Related Art Conventionally, an optical disc, for example, a compact disc (CD) is produced by the process shown in FIG.

First, as shown in FIG. 3A, a disk substrate 2 is prepared by a stamper 1 having concave and convex pits 1a opposite to the recording information signal. The disc substrate 2 is formed by injection molding a resin material having light transparency, for example, polycarbonate. On the surface 2a of the disk substrate 2 thus formed, a concavo-convex pattern in which the concavities and convexities of the pits 1a on the surface of the stamper 1 are reversed, that is, pits corresponding to the recording information signal are formed.

A metal film 3 for reflection is formed on the pit forming surface 2a of the disk substrate 2 (b). This metal film 3
Is formed by, for example, vacuum deposition or sputtering of aluminum (Al).

In this way, the protective film 4 is formed of hard resin on the metal film 3 side of the disk substrate 2 on which the metal film 3 is formed (c). The formation of the protective film 4 is performed by the disk substrate 2
Spin coating, that is, by dropping a liquid of UV resin (ultraviolet curing resin) while rotating at high speed, the liquid of UV resin is centrifugally applied to the surface of the disk substrate 2, that is, the surface on which the metal film 3 is formed. It spreads evenly thinly and is cured by irradiation with ultraviolet rays in this state to form the protective film 4.

The disk substrate 2 on which the protective film 4 is formed is subjected to center hole and outer shape processing.

Then, a label 5 is printed on the surface of the protective film 4 of the disc substrate 2 to display the contents of recorded information and the like (d). The printing of the label 5 is performed by screen printing or offset printing using UV ink (ultraviolet curable resin ink) to form a label printing film, and a transparent ink as the top coat 6 is printed on the label printing film 5. Apply.

Conventionally, a compact disc (CD) has been produced by the above steps.

[0009]

However, the optical disc (compact disc) produced as described above.
Forms a label print film on the surface of the protective film on the disc substrate, and this printed film is exposed to the surface of the protective film, so it is easy to damage, drop off or deteriorate, and to prevent this. The print film must be resistant to scratches and deterioration, and as a result, the type of printing ink and the printing method are limited, and the print film is used as a top coat for high quality and protection of the print film. Since it is necessary to print a transparent ink on the top of the disk, the number of manufacturing steps of the disk is increased, and the material cost is increased and the cost is increased.

The present invention has been made in view of the above points, and damages or drops a printed film such as a label of a disk without limiting the printing ink and the printing method and without increasing the number of manufacturing steps. It is an object of the present invention to provide a method for manufacturing an optical disc formed so as to prevent such problems.

[0011]

In order to achieve the above object, the present invention provides a step of forming a reflective film on a recording surface of a disk substrate on which information is recorded in a concavo-convex pattern, and a reflective film forming surface of the disk substrate. An optical disc including a step of applying a protective film on the side, a step of semi-curing the protective film, a step of printing on the semi-cured protective film, and a step of completely curing the printed semi-cured protective film. Is to be manufactured.

In the above steps, printing on the semi-cured protective film is preferably performed by a non-contact method such as an ink jet method.

[0013]

As described above, according to the present invention, in the optical disc, the printing of characters, symbols, and design images for improving the texture of the recorded contents is performed by applying the protective coating on the reflective film formation surface side of the disc substrate. Since the printing is performed in the semi-cured state of the film, the printed film is embedded in the protective film, and then the protective film is completely cured to be integrated with the protective film, whereby the top coat is not formed. The printed film is also protected and damage and dropout are prevented.

In the printing of the protective film in the semi-cured state, the ink is formed by the ink jet method,
The toner and the like are surely embedded in the protective film.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical disc and a method of manufacturing the same according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an enlarged cross-sectional view of a portion of an example optical disc produced according to the present invention. In FIG. 1, 11 is a compact disc (C
D), and 12 is a disk substrate made of a transparent resin such as polycarbonate, on the surface of which a digital signal portion (hereinafter referred to as a recording surface) 12a in the form of pits is formed, and a metal film for reflection on the recording surface 12a. A (hereinafter referred to as a reflection film) 13 is formed by vapor deposition of aluminum, for example.

On the reflective film 13, a transparent resin such as U
The protective film 14 is formed of V resin (ultraviolet curable resin).

In the present embodiment, the compact disk (which is formed by embedding the printing film 15 on the surface of the protective film 14 for displaying characters, symbols and design images for improving the texture of the recorded information content) CD) 11 has been created.

Next, an example of a method for manufacturing a compact disc (CD) as an optical disc according to the present invention will be described with reference to FIG.

In FIG. 2, a shows a step of forming a disc substrate by a stamper, and a stamper 1 having concave and convex pits 1a formed according to a required recording information signal is used as a recording surface as a digital signal portion in a required pit row. 12
A disk substrate 12 having a formed thereon is prepared.

On the recording surface 12a of the disk substrate 12 thus formed, aluminum is deposited in a thin film form by vapor deposition or sputtering to form the reflection film 13 (b).

Thus, the recording surface 1 of the disk substrate 12
An ultraviolet curable resin 14 ₁ which becomes a protective film 14 is applied onto the reflection film 13 formed on the surface 2a by the spin coating method as in the case of the conventional example described above (c), and this resin layer is irradiated with ultraviolet light from an ultraviolet light source L. Is irradiated for a short time or with a small amount of light to semi-cure the resin layer to form a semi-cured protective film 14 ₂ (d).

[0023] Then, the semi-cured protective film 14 ₂ of the surface of the recording information content in the side letters, symbols or designs image or the like printed film of 1
5 is formed. That is, in this example, the printing is performed by the inkjet method, and the ink I is ejected from the ink nozzle N and sprayed on the surface of the semi-cured protective film 14 ₂ , so that the ink I is embedded in the surface of the protective film 14 _2. The printed film 15 is formed in the state of being embedded and is formed (e).

[0024] In this way, the semi-cured protective film 14 ₂ after forming the printed layer 15, print layer 15 by completely cured by irradiation with ultraviolet rays by an ultraviolet light source L a semi-cured protective film 14 ₂ protective film It is fixed and integrated in a state of being embedded in the surface side of 14 (f).

The compact disk 11 as an optical disk is manufactured by the above steps.

The compact disk 11 having the above-described structure is fixed and integrated with the print film 15 embedded in the front surface side of the protective film 14 that covers and protects the reflective film 13. 15 is surely protected to prevent damage, dropout, etc. Therefore, it is possible to omit the step of printing a transparent ink for the purpose of protecting the printed film 15 called a top coat. Further, since the printing film 15 is printed in a semi-cured state of the protective film 14, delicate high-definition printing can be performed without ink or toner splashing or dropping even if an inkjet method is used, and the texture is remarkably improved. To be done.

As described above, the present invention can be applied to the compact disc (C
Although one embodiment has been described in the case of being applied to D), the present invention is also applicable to a video disc, an optical disc capable of recording, reproducing or erasing digital signals such as still images and document files.

The materials for the disk substrate, the reflection film and the protective film of these optical disks are acrylic resin for the disk substrate, gold (Au), chromium (Cr) for the reflective film, and the like for the protective film. Is not limited to UV resin, other photo-curable resin can be used, and a spray method and a roll coater method can be applied to the protective film in addition to the spin-coating method of the photo-curable resin.

[0029]

As described above, according to the present invention, label printing of characters, symbols and design images for improving the texture of the recorded contents of the optical disk is performed in a semi-cured state of the protective film that protects the reflective film. The printing ink becomes embedded in the surface side of the protective film, and especially when printing with an ink jet method or the like in which ink, toner, etc. are sprayed at a predetermined pressure, the ink, toner, etc. are surely applied to the semi-cured protective film. By embedding and completely curing the protective film, the printed film is integrated with the protective film to prevent damage, dropout, etc., and high-definition printing becomes possible to further improve the sense of quality.

Further, since the printing film is integrated with the protective film, the step of printing the transparent ink as the top coat for the purpose of protection can be omitted, and the number of disk manufacturing steps can be reduced, resulting in cost reduction. It will be possible.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of a part of an optical disc according to the present invention.

FIG. 2 is an explanatory diagram of a manufacturing process of an example of the optical disc of the same.

FIG. 3 is an explanatory view of a manufacturing process of a conventional compact disc.

[Explanation of symbols]

 1 Stamper 12 Disk Substrate 12a Recording Surface 13 Reflective Film 14 Protective Film 15 Printing Film I Ink

Claims (2)

[Claims] 1. A step of forming a reflective film on a recording surface of a disk substrate on which information is recorded in a concavo-convex pattern, a step of applying a protective film on the reflective film forming surface side of the disk substrate, and the protective film. A method for manufacturing an optical disc, comprising the steps of: semi-curing, a step of printing on the semi-cured protective film, and a step of completely curing the printed semi-cured protective film. 2. The printing on the semi-cured protective film is performed by a non-contact method.
A method for manufacturing a disc according to.