JPH06336086A - Optical recording medium - Google Patents

Abstract

PURPOSE:To enable the recording reproduction due to conventional semiconductor laser and short wave blue laser, in an optical recording medium wherein a recording layer and a reflecting layer are formed on a translucent substrate, by forming the recording layer using a mixture of two kinds of specific cyanine org. dyes. CONSTITUTION:An optical recording medium is constituted by forming a recording layer on a translucent substsate and forming a reflecting layer and a protective layer thereon. Herein, the recording layer is formed by coating the substrate with a soln. prepared by dissolving a cyanine dye NC-22 (1,1'-di-n-buthyl-3,3,3',3'- tetramethyl-4,5-, 4',5'-dibenzo-2,2'-indodicarbocyanine perchlorate) represented by formula I and a cyanine dye SNC-2 (1,1'-diethyl-3,3,3',3'-tetramethyl-2,2'- indocarbocyanine iodide) represented by formula II, for example, in diacetone alcohol. In the formula II, R is CH3, C2H5, C3H7 or C4H9 and X is Cl<-> or ClO4<->.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium for recording information with a laser beam, and more particularly to a recording medium capable of reproducing in compliance with the compact disc standard.

[0002]

2. Description of the Related Art A recordable optical information recording medium is a very widespread compact disc (hereinafter referred to as a CD).
It is desirable to be able to reproduce in conformity with. Therefore, many studies have been made, one of which is Japanese Patent Laid-Open No.
There is a technique disclosed in 87339. These use an organic dye-based recording film and a reflective film to obtain a high reflectivity in which the amount of light reflected on the incident side of laser light satisfies the CD standard, and when reproducing data, conform to the CD format. It is a recordable optical information recording medium which can obtain an output signal.

Further, in recent years, the development of an optical disc having a higher recording density has been advanced, and there has been a problem that the spot diameter of the light beam must be made smaller in order to increase the recording density. Therefore, conventional 780nm
From a semiconductor laser centered on the SHG element to a green laser or a blue laser in which the wavelength of light is shortened by using an SHG element or the like, and these lasers are narrowed down to the diffraction limit to reduce the beam spot diameter to reduce the recording density. Ways to raise it are under way.

[0004]

In the conventional optical recording medium using an organic dye for recording / reproducing with a semiconductor laser,
Recording with a short-wavelength blue laser is not possible because there is almost no absorption of dye at the wavelength of the blue laser. It is an object of the present invention to provide an optical recording medium having a high reflectance, which is capable of recording / reproducing with a short wavelength blue laser as well as recording / reproducing with a conventional semiconductor laser.

[0005]

Therefore, in the present invention, in an optical recording medium in which a recording layer is formed on a transparent substrate and a reflective layer is formed on the recording layer, the recording layer is formed. It is characterized by using a mixture of a cyanine organic dye corresponding to a semiconductor laser and a cyanine organic dye corresponding to a short wavelength blue laser.

[0006]

Embodiment 1 An embodiment of the present invention will be described with reference to the sectional configuration diagram of FIG. In the figure, a cyanine dye NC represented by the chemical formula (Formula 1) is formed on a substrate made of polycarbonate.
-22 (1,1'-di-n-butyl-3,3,3 ',
3'-Tetramethyl-4,5-, 4 ', 5'-dibenzo-2,2'-indodicarbocyanine perchlorate)
[Manufactured by Japan Photosensitive Dye Research Institute] 0.2 g and cyanine dye SNC-2 (1,1′-diethyl-) represented by the chemical formula (Formula 2)
3,3,3 ', 3'-tetramethyl-2,2'-indocarbocyanine iodide) [manufactured by Japan Photosensitive Dye Research Institute] 0.02 g was dissolved in 3 ml of diacetone alcohol, and spin coating was performed. It is used to coat at 6000 rpm to form the recording layer 2. On the surface of this recording layer 2,
The reflective layer 3 made of aluminum is 500 A ° by the sputtering method.
Form a film. Further, a UV resin is coated by a spin coating method and irradiated with ultraviolet rays to be cured to form a protective layer 4. When an optical beam spot is irradiated onto the optical recording medium having the above structure, as shown in FIG. 2, the irradiated portion is heated and melted, and the partially decomposed dye and the polycarbonate, which is the substrate material that is softened by heating, are brought into contact with each other. Acting on
A deformed portion is formed at the interface between the recording layer and the substrate, and this becomes a recording pit. The substrate-side incident reflectance of the recording layer of this recording medium is shown in FIG.

(Example 2) As another example, a cyanine dye NK-3212 (1, 1 ', 3, 3, 3) represented by the chemical formula (Formula 3) is formed on a substrate made of polycarbonate.
3 ', 3'-hexamethyl-2,2'-indocyanine perchlorate) [manufactured by Japan Photosensitive Dye Research Institute] 0.02 g
And the cyanine dye NC-2 (1,
1'-di-n-butyl-3,3,3 ', 3'-tetramethyl-4,5-, 4', 5'-dibenzo-2,2'-indodicarbocyanine bromide) [Japan Photosensitive Dye Laboratory product] 0.2 g of the solution dissolved in 3 ml of diacetone alcohol is coated at 6000 rpm by a spin coating method to form the recording layer 2. On the surface of this recording layer 2,
The reflective layer 3 made of aluminum is 500 A ° by the sputtering method.
Form a film. Further, a UV resin is coated by a spin coating method and irradiated with ultraviolet rays to be cured to form a protective layer 4. The substrate-side incident reflectance of the recording layer of this recording medium is shown in FIG.

(Example 3) As another example, a cyanine dye NC-22 (1,1'-di-n-butyl-3,3, represented by the chemical formula 1) is formed on a substrate made of polycarbonate. , 3 ', 3'-tetramethyl-4,5-,
4 ', 5'-dibenzo-2,2'-indodicarbocyanine perchlorate) [manufactured by Japan Photosensitive Dye Research Institute] 0.2
g and the cyanine dye NK-321 represented by the chemical formula (Formula 3)
2 (1,1 ', 3,3,3', 3'-hexamethyl-
2,2′-indocyanine perchlorate) [manufactured by Japan Photosensitive Dye Research Institute] 0.02 g, diacetone alcohol 3
The solution dissolved in ml was spin coated at 6000
The recording layer 2 is formed by coating at rpm. This recording layer 2
A reflective layer 3 made of aluminum is formed on the surface of the substrate by sputtering at 500 A °. UV by spin coating
Protective layer 4 coated with resin and cured by irradiation with ultraviolet rays
To form. The substrate-side incident reflectance of the recording layer of this recording medium is shown in FIG.

(Example 4) As another example, a cyanine dye SNC-2 (1,1'-diethyl-3, represented by the chemical formula 2) was formed on a substrate made of polycarbonate.
3,3 ′, 3′-Tetramethyl-2,2′-indocarbocyanine iodide) [manufactured by Japan Photosensitive Dye Research Institute]
A solution of 0.02 g dissolved in 3 ml of diacetone alcohol was spin-coated and the cyanine dye NC-2 (1,1′-di-n-butyl-3,3,3) represented by the chemical formula (Formula 4).
3 ', 3'-Tetramethyl-4,5-, 4', 5'-dibenzo-2,2'-indodicarbocyanine bromide) [manufactured by Japan Photosensitive Dye Research Institute] 600 g using 0.2 g
The recording layer 2 is formed by coating at 0 rpm. On the surface of the recording layer 2, a reflective layer 3 made of aluminum is formed by a sputtering method.
Is formed at 500 A °. Furthermore, by spin coating method, U
The V resin is coated and is irradiated with ultraviolet rays to be cured to form the protective layer 4. The substrate-side incident reflectance of the recording layer of this recording medium is shown in FIG.

In these embodiments, the recording laser is
When a 0 nm semiconductor laser and a 488 nm argon laser were used, the substrate-side incident reflectance was a value that sufficiently satisfied the substrate-side incident specular partial reflectance Ro of CD-WO, CD standard.

[0011]

According to the present invention, it is possible to provide an optical recording medium having a high reflectance, which is capable of recording / reproducing with a conventional semiconductor laser and recording / reproducing with a short wavelength blue laser.

[Brief description of drawings]

FIG. 1 is a sectional configuration diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a recording mechanism in an embodiment according to the present invention.

FIG. 3 is a diagram showing characteristics of an example according to the present invention.

FIG. 4 is a diagram showing characteristics of an example according to the present invention.

FIG. 5 is a diagram showing characteristics of an example according to the present invention.

FIG. 6 is a diagram showing characteristics of an example according to the present invention.

[Explanation of symbols]

 1 substrate 2 recording layer 3 reflective layer 4 protective layer

Claims (4)

[Claims] 1. An optical recording medium having a recording layer formed on a transparent substrate and a reflective layer formed on the recording layer, wherein the recording layer is represented by the chemical formulas 1 and 2. An optical recording medium comprising a mixture of cyanine organic dyes. [Chemical 1] [Chemical 2] 2. The optical recording medium according to claim 1, wherein the recording layer comprises a mixture of a cyanine organic dye represented by the chemical formula 3 and a cyanine organic dye represented by the chemical formula 4. [Chemical 3] [Chemical 4] 3. The mixture of a cyanine organic dye represented by the chemical formula 1 and a cyanine organic dye represented by the chemical formula 3 is used for the recording layer.
The optical recording medium described. 4. The mixture of a cyanine-based organic dye represented by the chemical formula (2) and a cyanine-based organic dye represented by the chemical formula (4) is used for the recording layer.
The optical recording medium described.