JP2822288B2 - Write-once optical disc media - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk medium for recording information by irradiating a laser beam and reproducing recorded data by reflected light of the radiated laser beam.

[0002]

2. Description of the Related Art At present, a read-only optical disk medium on which data is recorded in advance and data cannot be recorded or erased thereafter has already been widely put into practical use in the audiovisual field and the information processing field. Among them, the most representative and widely spread are a compact disk (CD) and a laser disk (LD). The specifications of recording and reproducing signals of the CD and LD are standardized as a CD format and an LD format. Are widely spread as CD players and LD players.

[0003] On the other hand, writable optical disk media have compatibility with CD and LD players that have already become widespread at the time of reproduction, and it is desired that they can be reproduced as they are. Recently, CD-R has been released as a writable optical disk medium having compatibility with a CD player.
No. 87339. CD-R satisfies the standard (Orange Book) for maintaining compatibility with CD players.

[0004]

However, in the case of CD-R, a recording film is formed by applying an organic dye on a transparent substrate having a pregroove by a spin coating method, and an Au reflection film is formed thereon. It has a structured structure. In order to increase the reproduction signal modulation degree (II / Itop) according to the Orange Book standard, the amount of dye that accumulates in the pre-groove must be increased. The step between the groove portion and the groove portion becomes small, and the push-pull amplitude, which is also in the Orange Book standard, may not satisfy the standard, and tracking servo is hardly applied.

When Al is used for the reflection film, the reflectance is 70% (semiconductor laser wavelength 780 nm ± 10 nm).
In order to achieve the above, it is necessary to provide an interference film between the organic dye film and the Al reflection film, so that the step between the land portion and the groove portion is further reduced, and a margin for achieving both the reproduction signal modulation degree and the push-pull amplitude is achieved. Becomes narrower. The above problem is the same when making the LD player compatible with the LD player. The present invention has been made to solve the above-mentioned conventional problems, and the object is to
It is an object of the present invention to provide an organic dye film write-once optical disc medium having a higher quality and a wider production margin, which is compatible with a standard (orange book) such as a CD player and an LD player.

In order to solve the above object, in the present invention, a V-groove type pregroove having a groove depth of 0.18 to 0.24 μm and a width of 0.4 to 1.0 μm above the groove is provided on the transparent substrate. It was decided to use something.

[0007]

In the optical disk medium according to the present invention, the groove depth of the transparent substrate is 0.18 to 0.24 μm, and the width of the groove is 0.4 to 0.24 μm.
Since a disk having a 1.0 μm V-groove type pre-groove is used, a high-quality write-once optical disc medium that satisfies the write-once CD standard (Orange Book Standard) or is compatible with LD players with a wide manufacturing margin Can be obtained.

[0008]

FIG. 1 is a sectional structural view of an optical disk medium according to the present invention, wherein 1a has a pregroove and has a refractive index of 1.
About 5 transparent substrates, specifically, polycarbonate, acrylic and the like are desirable, but not limited thereto. 2a is a light absorbing layer, the real part N of the complex refractive index
abs = 2.2-3.0, imaginary part Kabs = 0.05-0.1, organic dye is coated with a thickness of 0.08 by spin coating or the like.
A film is formed to a thickness of 0.15 μm.

The interference layer 3a preferably has a refractive index of 1.5 to 2.0, and is made of AlN, SiO ₂ , S
Using i ₃ N ₄ or the like, the film is formed to have a thickness of 0.015 to 0.15 μm according to the thickness of the light absorption layer. However , the reflection layer 4
in the case of using Au in a can, it is not always necessary to provide the interference layer 3a. For the reflective layer 4a, Al can be used, and the reflective layer 4a is formed to a thickness of 0.05 μm or more. The reflection layer 4a
A protective layer 5a of UV resin or the like may be provided on the reflective layer 4a in order to prevent oxidation, peeling, and the like. Further, in order to make the LD player compatible, two disks having the above structure are bonded together on the UV resin side.

Here, as a typical example of the disk structure, the results of the embodiment are shown in the structure shown in FIG. 1b is a polycarbonate substrate having a thickness of 1.2 mm, an outer diameter of 120 mmφ, and an inner diameter of 15 mmφ.
The groove depth was changed to 1.0 μm and the groove depth Gd was changed to a V-shaped groove of 0.1 to 0.3 μm. 2b is 0.2 g of 1,1,1,1 tetramethyl 3,3n butyl 6,7,6,7 dibenzo 2,2 indodicarbocyanine bromide (product number NK3567, manufactured by Japan Photographic Dye Laboratories). This is a light absorbing layer formed by dissolving in 3 ml of a diacetone alcohol solvent and applying the solution to the surface of the substrate 1b by spin coating to form a film having a thickness of 0.12 μm.

Reference numeral 3b denotes an AlN film obtained by a reactive sputtering method using an N ₂ gas and an Al target, and has a thickness of 0.05 μm. Reference numeral 4b denotes an Al reflective film formed by a sputtering method using an Al target, and the film thickness was 0.07 μm. UV on top of this
The resin film 5b was formed to a thickness of about 10 μm by spin coating.

FIG. 3 is a characteristic diagram showing the influence of the substrate groove depth Gd on the reflectivity.
28 μm), the reflectivity of Itop is 70% or more. Therefore, it can be seen that the substrate of the present invention satisfies the Orange Book standard (Itop reflectance of 65% or more). FIG. 4 is a characteristic diagram showing the effect of the substrate groove depth Gd on the degree of signal modulation, and it can be seen that the larger the groove, the larger the depth. In order to satisfy the Orange Book standard (signal modulation degree ≧ 0.6), the groove depth Gd should be equal to 0.
What is necessary is just to be in the range of 15 to 0.24 μm. The width Gw of the upper part of the above groove is 0.5 μm.

FIG. 5 is a characteristic diagram showing the influence of the groove depth Gd on the push-pull. The push-pull increases as the groove depth Gd increases. It can be seen that the groove depth Gd should be within the range of 0.18 to 0.30 μm in order to satisfy the push-pull range of 0.04 to 0.09 defined by the Orange Book standard. The width Gw of the upper part of the groove at this time
Is 0.5 μm. FIG. 6 shows the width Gw of the upper part of the groove.
FIG. 4 is a characteristic diagram showing the influence of the groove width G on the push-pull.
The push-pull increases as w increases. In order to satisfy 0.04 to 0.09 of the Orange Book standard, it is necessary to use 0.1.
It is understood that it is sufficient if the thickness is 4 μm or more. However, when the width Gw of the upper part of the groove is 1.1 μm or more, the dye and the substrate are not sufficiently deformed by the laser beam, and the signal modulation degree does not satisfy the standard value. Therefore, the width G at the top of the groove
w may be 0.4 to 1.0 μm.

From the above results, in order to satisfy both the signal modulation degree and the push-pull, the groove depth Gd should be 0.18 to 0.18.
It can be seen that a V-groove type pregroove having a width of 0.24 μm and a width of 0.4 to 1.0 μm above the groove is required. Substrate 1
1.2mm thickness, outer diameter 300mmφ, inner diameter 35mm
A disc having the same structure as that shown in Fig. 2 was attached using an acrylic substrate of φ, and video and audio FM signals in accordance with the LD format were recorded on the disc and played back with a commercially available LD player. Obtained.

[0015]

According to the write-once optical disc medium according to the present invention, the standard (Orange Book) and L for a CD player and the like are used.
A high-quality writable optical disk medium compatible with the D player can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional structural view of an optical disk medium according to the present invention.

FIG. 2 is a sectional structural view of a typical optical disk medium for specifically describing an embodiment.

FIG. 3 is a characteristic diagram showing an influence of a substrate groove depth on a reflectance.

FIG. 4 is a characteristic diagram showing an influence of a substrate groove depth on a signal modulation degree.

FIG. 5 is a characteristic diagram showing the influence of the width of the upper part of the substrate groove on the push-pull.

FIG. 6 is a characteristic diagram showing an influence of a width of an upper portion of a substrate groove on a push-pull.

[Explanation of symbols]

 1a, 1b Substrate 2a, 2b Dye recording film 3a, 3b Interference film 4a, 4b Reflection film 5a, 5b UV resin film

Claims (2)

(57) [Claims] A light-transmitting substrate; a light-absorbing layer formed on the substrate; an interference layer formed on the light-absorbing layer;
A write-once optical disc medium having a reflective layer formed on the interference layer, wherein the substrate has a groove depth of 0.18 to 0.1.
A write-once optical disc medium having a V-groove type pregroove having a width of 24 μm and a width of 0.4 to 1.0 μm above a groove. 2. The optical information medium according to claim 1, wherein the light absorption layer has a real part Nabs of a complex refractive index of 2.2 to 2.2.
3.0 and the imaginary part Kabs is 0.05
The organic dye in the range of 0.1 to 0.1 is coated with a thickness of 0.08 to 0.1.
Is obtained by film formation with 15 [mu] m, the interference layer is within the thickness of 0.015~0.15μm A l N, Si
O ₂ and / or Si ₂ N ₃ film.
The reflection layer is made of an Al film having a thickness of 0.05 μm to 0.07 μm.
A write-once optical disc medium characterized by being formed by: