JPH05305772A - Optical recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical recording medium capable of recording data with a short wavelength laser in high density using small recording spots by laminating a recording layer containing a cyanine organic color and a reflective layer sequentially on a light-transmissive substrate. CONSTITUTION:A recording layer containing an cyanine organic color is formed on a substrate 1 with light transmissivity such as plastic or glass. In addition, a reflective layer is laminated on the recording layer to manufacture an optical recording medium. In concrete terms, a solution in which a color is dissolved in a mixture of diacetone alcohol of 2-(1',3'-diethyl-2'-thioxyo-4'- oxoimidazolidine-5'-iridine)-3-ethylbenzothiazoline, and trifluoroethanol, is spin- coated on a substrate of polycarbonate, thus forming a recording layer. Next, the reflective layer 3 of aluminum is laminated on the surface of the recording layer using a sputtering method to obtain an optical recording medium. It is possible to form a protecting layer by coating a UV resin on the reflective layer and irradiating the coat with an ultraviolet beam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium for recording information with a laser beam, and more particularly to a recording medium which can be reproduced according to 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, and one of them is the technique disclosed in Japanese Patent Application Laid-Open No. 2-87339. These use an organic dye-based recording film and a reflective film to obtain a high reflectance 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 that can obtain an output signal.

[0003]

In recent years, development of an optical disc having a higher recording density has been advanced, and there is a problem that the spot diameter of the light beam must be made smaller in order to increase the recording density. It was Therefore, from the conventional semiconductor laser centered at 780 nm, using a SHG element or the like, a green laser or a blue laser whose light wavelength is shortened is used, and these lasers are narrowed down to the diffraction limit to reduce the beam spot diameter. The method of increasing the recording density is being promoted.

As a matter of course, the recording medium must also be capable of recording with beam spots having these wavelengths of light. It is an object of the present invention to provide an optical recording medium capable of recording with a laser having a short wavelength, which can achieve higher density by using a smaller recording spot.

[0005]

Therefore, according to 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 It is characterized by using the cyanine-based organic dye shown in Chemical formula 1.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described with reference to the sectional view of FIG. In the figure, the cyanine dye NK-2093 (2
-(1 ', 3'-diethyl-2'-thioxo-4'-oxoimidazolidine-5'-ylidene) -3-ethylbenzothiazoline) [manufactured by Japan Photosensitive Dye Research Institute] 0.1 gr
Is coated with a dye solution dissolved in 3 ml of diacetone alcohol, trifluoroethanol or a mixture thereof at 2500 rpm by a spin coating method to form the recording layer 2.

Subsequently, a reflection layer 3 made of aluminum is formed on the surface of the recording layer 2 by a sputtering method at 500 A °. 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 the optical recording medium having the above structure is irradiated with a beam spot, 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 heat-softened in contact with the dye, are mutually dissolved. As a result, a deformed portion is formed at the interface between the dye layer and the substrate, and this becomes a recording pit.

The substrate side incident reflectance of the dye recording layer of this recording medium is shown in FIG. In this embodiment, the maximum absorption wavelength is in the first half of the 400 nm range, which can be recorded by a short wavelength laser, and when a 488 nm argon laser is used as the recording laser,
The substrate incident reflectance was a value that sufficiently satisfied the substrate-side incident mirror surface partial reflectance Ro of 70% of the CD-WO standard.

[0009]

According to the present invention, it is possible to provide an optical recording medium using a laser having a short wavelength and capable of recording higher density information.

[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 of an embodiment according to the present invention.

FIG. 3 is a characteristic 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 (1)

[Claims] 1. 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, wherein the recording layer comprises a cyanine-based organic dye represented by Chemical Formula 1. An optical recording medium characterized by being used. [Chemical 1]