Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Radiation sensitive composition or product or process of making
Patent
1987-02-25
1988-09-06
Michl, Paul R.
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
430495, 430945, 540139, G11B 724, G03C 172, G03C 516
Patent
active
047693070
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to an optical recording member containing phthalocyanine type coloring matter in its information recording layer.
More specifically, the invention is concerned with such optical recording member that performs recording of information utilizing changes in the state of substance due to light energy having an oscillating wavelength of a semiconductor laser.
BACKGROUND ART
Development in the optical recording which utilizes laser technology has been desired particularly in recent years owing to its capability of preservation and reproduction of information recorded in high density.
As one example of such optical recording, there may be mentioned an optical disc.
In general, the optical disc carries out high density recording of information by irradiation of laser beam which has been collimated to a beam diameter of 1 .mu.m or so onto a thin recording layer provided on a circular base member
The information recording is effected by thermal deformation of the recording layer such as its decomposition, evaporation, dissolution, and others which take place at particular portions of the recording layer owing to its absorption of the laser energy as irradiated onto it. On the other hand, the reproduction of the recorded information is done by reading of a difference in the reflection factor between the portion where the deformation has taken place by the laser beam and the portion where no deformation has occurred.
For the recording member, therefore, it is necessary to have high absorptivity to the laser beam of a particular wavelength to be used for the recording, because the recording member is required to absorb energy of the laser beam with good efficiency, and also to have high reflection factor to the laser beam of a particular wavelength for use in the reproduction so as to carry out the accurate reproduction of the recorded information.
For such optical recording member, there have so far been proposed various inorganic compounds such as metals, metal compounds, chalcogenides, and so on. However, the thin films made of these inorganic compounds have various disadvantages such that they are susceptible to oxidation in the air, difficult to preserve over a long period of time, sensitive to the ultraviolet part or the visible part of the light rays, not durable against sun light and other light, and so forth.
As the organic compounds to be used for the recording member, there have so far been proposed cyanine type coloring matter, squalerium type coloring matter, naphthoquinone type coloring matter, phthalocyanine type coloring matter, and so on. Of these various coloring matters, the phthalocyanine type coloring matter is highly stable to the ultraviolet part and the visible part of the light rays, while it is remarkably inferior in its solubility to organic solvents, hence it has a shortcoming such that the economically advantageous coating method cannot be adopted for the thin film forming.
DISCLOSURE OF INVENTION
It is an object of the present invention to provide an optical recording member of an organic substance which has high sensitivity to writing by the laser beam, particularly the semiconductor laser beam, has good stability in its preservation, and yet, is capable of forming the thin film by the coating method.
The present invention has its gist in an optical recording member comprising a substrate; and a recording layer which contains therein a light absorbing substance to be represented by the following general formula [I]: ##STR2## (where: R.sup.1, R.sup.2, R.sup.3 and R.sup.4 represent the alkyl group having C.sub.1 to C.sub.22 which may be substituted, or --C.sub.2 H.sub.4 O).sub.n Y, or ##STR3## (x denoting halogen atom; Y representing hydrogen atom, aryl group, or alkyl group which may be substituted; n indicating an integer of from 1 to 4; m indicating an integer of 0, 1 or 2; and Z denoting hydrogen atom, carboxylic acid group, carboxylic acid ester group, aryl group, alkyl group which may be substituted, or alkoxy group which may be substitute
REFERENCES:
patent: 2122137 (1938-06-01), Gassner et al.
patent: 2795583 (1957-06-01), Martin et al.
patent: 2859219 (1958-11-01), Randall et al.
patent: 4492750 (1985-01-01), Law et al.
Kurose Yutaka
Maeda Shuichi
Ozawa Tetsuo
Buscher Mark R.
Michl Paul R.
Mitsubishi Chemical Industries Limited
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