JPH0348843A - Optical recording medium and manufacture of same - Google Patents

Abstract

PURPOSE:To enable recording and erasing using light by recording information on a compound medium with a light of wavelength corresponding to the absorption maximum of the compound in a state of first molecular association and erasing it with a light of another wavelength corresponding to that of the compound in a state of second molecular association. CONSTITUTION:The compound (A) to be used for the optical recording medium has >= 2 kinds of molecular association states different in absorption wavelength, and information is recorded by using the light of the wavelength of the first absorption maximum in the state of the first molecular association, and it is erased by using the light of that of the second absorption maximum in the state of the second molecular association. It is preferred to use a dye stuff compound having association product J and association product H for the com pound (A) and a salt formed between a cyanine dye stuff of formula I and dialkylammonium, such as dioctadecyl-dimethylammonium or a mixture of this compound and a straight-chain saturated fatty acid ester, such as methyl stearate.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optical recording medium used for optical discs for recording information and a method for manufacturing the same.

2. Description of the Related Art One type of optical recording medium using an organic material as a recording medium utilizes an aggregate, which is a characteristic molecular aggregation state of dye molecules. Among these association states, an optical recording medium using a j-aggregate that exhibits a sharp absorption spectrum (narrow peak wavelength half-width) has been reported, and the Langmuir-Prodgett (hereinafter abbreviated as LB) method is used to thin the film. How to use the power (e.g.
Letter Volume 49 (1986) Pages 1677 to 167
9 pages (Appl, Phys, Lett, 19(1)
986) PP1677-1679)
Recording on such an optical recording medium is performed by irradiating a laser beam with a wavelength that matches the peak absorption wavelength, and although the corresponding peak in the absorption spectrum disappears due to the thermal mode, recording is performed depending on the presence or absence of that peak. Regeneration is performed by detecting the intensity.

Many aggregates, such as trimers, are known as associated states of dye molecules. In particular, they exhibit narrow half-widths (＼ sharp absorption spectra) (the peak absorption wavelength of the metal alloy is monomeric). Even though J aggregates shifted to longer wavelengths than the absorption peak wavelength of the body and H (or Ho, hereinafter referred to collectively as H) aggregates shifted to shorter wavelengths are known, the LB method can form ultra-thin organic films. Optical recording using J-aggregates of dyes is a method that is not only excellent in controlling the film thickness of the recording layer of an optical recording medium, but also excellent in controlling the association state of dye molecules. In the medium (top
Conventionally, the method of erasing the recorded state was to use a high-humidity heat treatment.
Atmospheric treatments such as solvent treatment were used.
The present invention aims to solve these problems of the prior art.

Means for Solving the Problems The ratio of formation of one molecular assembly state to another molecular assembly state and strength in a medium is inversely proportional to each other. It is controlled by irradiation, and recording is performed by irradiating a compound that has two or more molecular assembly states with different absorption wavelengths with light of a wavelength corresponding to the absorption of one molecular assembly state ((and other methods). This is an optical recording medium that performs erasing by irradiating light with a wavelength corresponding to one molecular aggregation state.

As a state of molecular assembly (like crystal form, lamellae, micelles, etc.) there are forces (using aggregates of molecules).

Action recording layer (-When irradiated with light corresponding to a certain molecular assembly state, a state transition occurs due to light absorption, and the proportion of the other molecular assembly state increases.However, the intensity of the absorption maximum decreases in the former and the latter When the molecular assembly state with increased absorption is irradiated with light of a wavelength corresponding to the molecular assembly state at a certain light intensity, the state shifts to the initial state. This case corresponds to erasure. Become.

Further, to give a more specific explanation, the association as a state of molecular assembly [NH association and J association are utilized. The LAJ aggregate shows a peak with a narrow half-width on the long wavelength side.Separation at eight wavelengths becomes clear because the absorption intensity at the absorption maximum wavelength is used as a signal.

Even though two light sources are used, since the wavelengths of the recording light and erasing light are different, erasing can also be performed by light irradiation.In optical recording media using this compound, an override method using two laser beams can be applied.

Embodiments Below, embodiments of the present invention will be described with reference to the drawings.

The compound used (translation: To the compound in which the cyanine dye with the structure shown above and dioctadecyl-dimethylammonium are salted in a 1:1 ratio, or the compound and methyl stearate, which is a linear saturated fatty acid ester, are formed in a 1:2 ratio) This is an example of a compound mixed with methyl stearate.The absorption maximum of the monomer of this compound is 550 nm. As a manufacturing method for optical recording media that forms multiple aggregates such as &H and J aggregates (see above), there is a method for controlling the thickness of the recording layer and the state of association in the manufacturing process without using the LB method. The aqueous phase is compressed using single-distilled water at a hydrothermal temperature of 16 ＼ at a compression speed of 10 mm/min, and then accumulated at a cumulative speed of 10 nm/min. Although the association state can be controlled by pressure, by applying a surface pressure of 15 mN/m at the air-water interface to a monomolecular film of this compound, two association states, H-aggregate and J-aggregate, can be established as stable molecular assembly states. Can only be formed.

Figure 1 (A) shows the absorption spectrum of the recording layer accumulated at a surface pressure of 15 mN/m. The wavelength of the recording light is 430 nm, and the wavelength of the J aggregate is 638 nm.As a light source, the wavelength of the recording light is 430 nm, and the wavelength of the erasing light is 64 nm.
A 0 nm dye laser is used. The recording energy is I
OmJ/cm2・Pulse Erasing energy is 30mJ/
Figure 1 (B) shows the absorption spectrum of the recorded state. C shows the absorption spectrum of the erased state. Recording light Each state can be repeatedly reproduced by irradiation with the erasing light. According to the present invention, it is possible to provide an optical recording medium in which recording and erasing can be performed using light by utilizing different molecular aggregation states in one type of recording layer.

[Brief explanation of drawings]

FIG. 1 is a graph showing the absorption spectrum of the recording layer of an embodiment of the optical recording medium of the present invention, in which (A) shows the initial stage of formation of the recording layer, and (B) shows the recording state. FIG. 2 (C) is a graph showing an absorption spectrum in an erased state, and FIG.

Claims (5)

[Claims] (1) Recording is performed by irradiating a compound with two or more molecular assembly states with different absorption wavelengths and irradiating it with light of a wavelength corresponding to the absorption of one of the molecular assembly states. An optical recording medium characterized in that erasing is performed by irradiating light with a wavelength corresponding to a collective state. (2) The optical recording medium according to claim 1, wherein the molecular assembly state is an aggregate. (3) The optical recording medium according to claim 2, wherein the compound having an aggregate is a dye compound having a J aggregate and an H aggregate; (4) The dye compound having the characteristics described in claim 3 is a compound obtained by forming a salt of a cyanine dye and dialkyl ammonium having the structure shown below, or a mixture of the compound and a straight chain saturated fatty acid ester. Characteristic optical recording media. ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ (5) A method for manufacturing an optical recording medium, characterized in that the method for coating a substrate with the recording layer of the optical recording medium according to any one of claims 1 to 4 is a Langmuir-Blodgett method.