PURPOSE: To enable recording with low energy and to prolong the shelf life by forming a recording layer consisting of coloring matter having a specified structure and polyvinyl butyral resin.
CONSTITUTION: The recording layer consisting of coloring matter having a structure represented by the formula and polyvinyl butyral resin is formed. In the formula, Y is -H, -SO3-, -SO3H, -SO3Na or -SO3K, l is an integer of 1W4, Y' is -H, -SO3H, -SO3Na or -SO3K, n is an integer of 1W4, m is 3 or 4, X- is a halogen ion or a univalent anion represented by ClO4 or BF4, and when Y is -SO3-, X- is not present. An additional recording type optical recording medium having the formed recording layer enables recording with semiconductor laser having ≤5mW low output, and degeneration in a wet environment can be considerably reduced.
HIROSE SUMIO
HOSONO YOUICHI
NISHIZAWA ISAO
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