JPH0863791A - Optical information recording medium and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a write-once optical disc capable of easily increasing the recording sensitivity without changing the characteristic of the dye and without deteriorating the characteristic of the disc, and a method for producing the same. An optical information recording medium having a translucent substrate 1, a recording layer 2 made of a dye material on the substrate 1, a reflective layer 3 on the recording layer 2, and a protective layer 4 on the reflective layer 3. And
The reflective layer 3 is an Au-Ti alloy film. This alloy film is Co
-It is formed by a sputtering method. In this case, keep the sputtering power input to the Au target constant,
By gradually reducing the sputtering power input to the Ti target, it is possible to easily manufacture an optical information recording medium in which the Ti composition ratio of the Au—Ti alloy film decreases from the recording layer 2 toward the protective layer 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk for recording / reproducing information by laser light, and more particularly to a write-once optical disk compatible with a compact disk (CD) or a compact disk-ROM (CD-ROM).

[0002]

2. Description of the Related Art Among information recording media using a condensed laser beam, a CD for reproducing music such as audio and a CD-ROM for computer-ROM have been widely spread. Such CDs and CD-ROMs are usually formed by forming a pit string having a CD format signal or a CD-ROM format signal on the surface of a transparent substrate such as polycarbonate at the time of injection molding, and reflecting aluminum, gold or the like by vapor deposition or sputtering. It is provided as a film and further coated with a protective film to manufacture.

On the other hand, as a write-once type optical disk having an editing function, a method of making an organic compound (dye) such as cyanine or phthalocyanine a recording film and providing a reflective film of gold or the like on the recording film to secure the reflectance has been put into practical use. ing.

[0004]

However, in the above-mentioned dye, there is a close relationship between the characteristics such as the light stability and the recording sensitivity when formed into a disc, and the characteristics such as the light stability are not deteriorated. There is a problem that it is difficult to increase the recording sensitivity.

The present invention has been made in view of this point,
An object of the present invention is to provide a write-once type optical disc which can easily increase the recording sensitivity without changing the characteristic of the dye and without deteriorating the characteristic of the disc, and a method for manufacturing the same.

[0006]

In order to solve this problem, an optical information recording medium according to a first aspect of the present invention, as shown in FIG.
Optical information recording having a transparent substrate 1, a recording layer 2 made of a dye material on the substrate 1, a reflective layer 3 on the recording layer 2, and a protective layer 4 on the reflective layer 3. In the medium, the reflective layer 3 is an Au-Ti alloy film.

According to a second aspect of the present invention, there is provided the optical information recording medium according to the first aspect, wherein the Ti composition ratio of the Au—Ti alloy film is 0.1 to 10 wt%.

An optical information recording medium according to a third aspect of the present invention is the optical information recording medium according to the first aspect, wherein the film thickness of the Au--Ti alloy film is 500Å.
It is characterized by the above.

An optical information recording medium according to a fourth aspect is the optical information recording medium according to the first or second aspect, wherein the Ti composition ratio of the Au—Ti alloy film changes in the thickness direction of the alloy film. To do.

An optical information recording medium according to a fifth aspect is the optical information recording medium according to the fourth aspect, wherein the Ti composition ratio of the Au--Ti alloy film is:
It is characterized by decreasing from the recording layer toward the protective layer.

According to a sixth aspect of the present invention, there is provided a method of manufacturing an optical information recording medium, wherein a transparent substrate, a recording layer made of a dye material on the substrate, a reflective layer on the recording layer, and the reflective layer. In producing an optical information recording medium having a protective layer on the layer, wherein the reflective layer is an Au-Ti alloy film, the Au-Ti alloy film is produced by a sputtering method. .

[0012]

In the optical information recording medium according to the first aspect of the present invention, the thermal conductivity is lowered by changing the conventional Au film from the conventional Au film to the Au-Ti alloy film. Therefore, the heat of the recording layer is hard to escape, and the recording sensitivity is increased.

In the optical information recording medium of claim 1, A
By providing the u-Ti alloy film, the thermal conductivity decreases, but at the same time the reflectance also decreases. Therefore, in claims 2 and 3, the Ti composition ratio of the Au-Ti alloy film is set to 0.1.
By setting the content to 10 wt% and the film thickness to 500 Å or more, it is possible to reduce the thermal conductivity of this alloy film and suppress the reduction of its reflectance.

When the Ti composition ratio is less than 0.1 wt%, the reflectance does not decrease, but the thermal conductivity also does not decrease. Ti
When the composition ratio of the above exceeds 10 wt%, the thermal conductivity decreases, but the reflectance also decreases. Further, when the film thickness of the Au—Ti alloy film is less than 500 Å, the reflectance decreases as the film thickness decreases, but when the film thickness is 500 Å or more, the reflectance becomes constant.

In the present invention, by changing the Ti composition ratio of the Au—Ti alloy film in the film thickness direction of the alloy film, a portion having high thermal conductivity and a portion having low thermal conductivity can be provided. . In particular, the Ti composition ratio according to claim 5 is
By decreasing from the recording layer to the protective layer, the thermal conductivity is low in the vicinity of the contact with the recording layer, the thermal conductivity becomes higher as it approaches the protective layer, and at the same time the reflectance becomes higher. That is, the recording sensitivity can be increased without lowering the reflectance as compared with the case where the composition ratio of Ti is not changed in the film thickness direction of the alloy film.

In the manufacturing method according to claim 6, A
When a u-Ti alloy film is formed, a sputtering method, particularly a Co-sputtering method is used, and the sputtering power input to the Au target is kept constant, and the sputtering power input to the Ti target is gradually reduced. The optical information recording medium according to claim 4 or 5 can be easily manufactured.

[0017]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 (see FIG. 1) Recording layer of phthalocyanine dye on a polycarbonate substrate 1 having a depth of 1400Å, a width of 0.45 μm, a guide groove having a pitch of 1.6 μm, a thickness of 1.2 mm, an outer diameter of 120 mm, and an inner diameter of 15 mm. 2 with a spin coater to a film thickness of 16
A film was formed on 00Å. Next, an Au—Ti alloy film was formed as a reflective layer 3 on the recording layer 2 to a thickness of 1200 Å. In this case, the Co-sputtering method of Au and Ti is used, and Ti
The sputtering powers of Au and Ti were adjusted so that the composition ratio was 8 wt%. Further, a protective layer 4 having a film thickness of 5 μm was provided on the alloy film by using an ultraviolet curable resin to manufacture an optical disk.

Example 2 The same as Example 1 except for the reflective layer, the reflective layer was formed by Co-sputtering of Au and Ti as follows.
That is, the Ti composition ratio at the start of sputtering is 8 wt.
%, Adjust the sputtering powers of Au and Ti respectively, and gradually reduce only the power of Ti,
It was set to zero at the same time as the end of sputtering. As a result, an optical disk having a film thickness of 1200 Å formed of an Au—Ti alloy film, in which the composition ratio of Ti decreases from the recording layer to the protective layer, was produced as a reflective layer.

Comparative Example 1 The same as in Examples 1 and 2 except for the reflective layer, and the reflective layer was Au.
By sputtering the target of
An optical disk having a 200Å Au film formed thereon was produced.

The optical discs of Examples 1 and 2 produced in this manner had a reflectance of 73% and 80%, respectively, and the optical disc of Comparative Example 1 had a reflectance of 82%. Next, using a semiconductor laser with a wavelength of 785 nm, a linear velocity of 1.4 m
When the EFM-CD format signal was recorded at / sec, the optimum laser powers were 7.0 mW and 7.7 mW for the optical discs of Examples 1 and 2, respectively, and 8.2 mW for the optical disc of Comparative Example 1. It was
The above results are summarized in [Table 1] below.

[0021]

[Table 1]

[0022]

As is apparent from the above description, in the optical information recording medium of the present invention, an Au-Ti alloy film is used for the reflective layer (claim 1), and the Ti composition ratio and the film thickness thereof are specified ( According to claims 2 and 3, the recording sensitivity can be improved while suppressing the decrease in reflectance. Further, by decreasing the Ti composition ratio of the Au—Ti alloy film from the recording layer toward the protective layer (claim 5), the recording sensitivity can be improved without substantially reducing the reflectance. Furthermore, Au-
A Ti alloy film is formed by a sputtering method (claim 6).
As a result, an optical information recording medium having the above characteristics can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of an optical information recording medium according to the present invention.

[Explanation of symbols]

 1 substrate 2 recording layer 3 reflective layer 4 protective layer

Claims (6)

[Claims] 1. An optical information recording medium comprising a transparent substrate, a recording layer made of a dye material on the substrate, a reflective layer on the recording layer, and a protective layer on the reflective layer. An optical information recording medium, wherein the reflective layer is an Au-Ti alloy film. 2. The optical information recording medium according to claim 1, wherein the Ti composition ratio of the Au—Ti alloy film is 0.1 to 10 wt%. 3. The film thickness of the Au—Ti alloy film is 500Å
The optical information recording medium according to claim 1, which is the above. 4. The Ti composition ratio of the Au—Ti alloy film is
The optical information recording medium according to claim 1 or 2, wherein the thickness of the alloy film changes in the thickness direction. 5. The Ti composition ratio of the Au—Ti alloy film is
The optical information recording medium according to claim 4, wherein the optical information recording medium has a decreasing amount from the recording layer toward the protective layer. 6. An optical information recording medium comprising a transparent substrate, a recording layer made of a dye material on the substrate, a reflective layer on the recording layer, and a protective layer on the reflective layer. A method for manufacturing an optical information recording medium, characterized in that, when the reflective layer is an Au-Ti alloy film, the Au-Ti alloy film is formed by a sputtering method.