JPS5862093A - Recording medium - Google Patents

Abstract

PURPOSE:To obtain a recording medium having a high light sensitivity and useful for an optic disk, by providing a recording layer comprising a metal and an organic material on a substrate, wherein the metal is so distributed that its amount is larger on the substrate side and the surface side while the organic material is so distributed that its amount is larger in a central part of the layer. CONSTITUTION:The recording medium consists of a plastic substrate 1, a tellurium layer (8mm. in thickness) 2, a copper phthalocyanine layer (20mm. in thickness) 3 and a tellurium layer (22mm. in thickness) 4. Tellurium (Te) used as a metal may be replaced by a metal having a low melting point and a low thermal conductivity such as Bi, In, Se, As, InGa and InSn or other similar metal. Copper phthalocyanine used as an organic material may be replaced by a material having a low melting point or a low boiling point or sublimable, such as fluorescein. The optic disk produced by using said recording medium comprises a pair of recording disks 5, 6 faced to each other through spacers 7, 8, and recording layers 5a, 6a provided on the faced surface side of the disks 5, 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording medium, and particularly to a recording medium used in an optical disk having high photosensitivity.

An optical disk recording medium (hereinafter referred to as a recording medium) has a recording layer of bismuth (Bi) or tellurium (Te) on a substrate surface.
) was formed using vapor deposition technology. Then, this recording layer is irradiated with a light beam such as a laser beam to record and reproduce information.

However, these recording media have insufficient sensitivity to record information using current semiconductor lasers, and it has been difficult to obtain high-quality reproduction tW information.

The present invention has been made in view of the above, and an object of the present invention is to provide a recording medium for an optical disc that has sufficient sensitivity during recording. Preferred embodiments of the present invention will be described below with reference to the drawings.

Figure gt is a configuration diagram of an embodiment of the present invention, where l is a plastic substrate, 2 is a tellurium (Te) layer (layer thickness: 8 mm).

3 is a copper phthalocyanine layer (layer thickness zowsL) 4 is a tellurium (Te) layer (layer thickness 22n).

Note that the melting point of Te is 450° C.9 The sublimation point of copper phthalocyanine is 400 to 42 G″C. Such a thin film layer can be easily formed by vapor deposition technology.

FIGS. 2(a) and 2(b) show an optical disk having a so-called air sandwich structure using the recording medium thus formed.

In FIG. 2(a) To3, 5.6 is a pair of recording disks, which are arranged facing each other with a spacer 7.8 in between, and the recording layers 5a and 6a are the opposing surfaces of these recording disks 5.6. installed on the side.

Using this optical disc, information was written and read using a semiconductor laser. The optical disk was rotated at 1,800 rpm and information was recorded.At this time, the laser power output on the disk surface was 3.3 tnW *The signal value of the reproduced signal was 40 dB, and a very high quality signal was obtained. Instead of Te, materials having a low melting point and low thermal conductivity such as Bi, In, Se, A@, InGa, and In8n may be used.

Further, instead of copper phthalocyanine, the organic material may be a low melting point, low boiling point, or sublimable material such as fluorescein.

What is the reason for the increased sensitivity in writing information?

This is thought to be because the high evaporability of the organic material in the organic material layer, which has sublimation properties, facilitates the melting and removal of the metal due to the heat generated by the light beam irradiation during writing.

In addition, the low thermal conductivity of the 4N size sheet is considered to be one of the reasons for this.

The laminated structure (C) in which the main components were distributed in the order of metal and organic metal from the substrate area was particularly sensitive. This is thought to be because high evaporation and sublimation properties were sufficiently expressed.

As is clear from the above description, the recording medium 1-t according to the present invention has a structure in which metal-containing layers are arranged on both sides of a low-melting point, low-boiling point, or sublimable organic material-containing layer as a recording layer. This has the advantage that the sensitivity during optical writing is increased, information can be written and read using a semiconductor laser, and the optical disk device becomes smaller.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of an optical disk according to the present invention. 1: Plastic substrate, 2: Tellurium layer, 3: Steel phthalocyanine 1, 4: Tellurium layer. Figure 1 Z Closed

Claims (2)

[Claims] (1) It has a substrate and a recording layer formed on the substrate. In the recording medium in which information is written and read by irradiating the recording layer with a light beam, the recording layer includes a metal and an organic material, and the metal is on the substrate side and on the surface of the recording layer. A recording medium characterized in that the organic material is distributed such that it is most abundant at the center of the recording layer and is least present on both sides of the center. (2) The metal has a low melting point and low thermal conductivity, and the organic material has a low melting point, a low boiling point, or a high sublimation property.
) The recording medium described in section 2.