| 摘要 |
PROBLEM TO BE SOLVED: To enable recording and reproduction within a short wavelength region by forming two or more recording layers containing dyes on a substrate so that at least two layers contain dyes mutually different in optical constance and at least one layer contains a dye wherein the half value width of the absorption spectrum of a membrane is a specific value or less. SOLUTION: A write-once optical recording disk 1 capable of performing recording and reproduction by two wavelengths, that is, a short wavelength (about 630-680nm) and a conventional wavelength of about 780nm is obtained by providing a laminated type recording layer 3 on the surface of a substrate and a reflecting layer 4 and a protective layer 5 are closely bonded to the recording layer 3. The recording layer 3 is formed from a first recording layer 31 containing coloring matter B wherein the real part (n) of a double refraction at a wavelength of 630nm or 650nm is 1.8-2.8 and the imaginary part (k) thereof is 0.4 or less and a second matter A wherein the real part (n) of double refraction at a wavelength of 780nm park (k) thereof is 0.15 or less and the half value width of the absorption spectrum of a membrane is 170nm or less. |
