Mitsui Chemicals, Inc.

Yamamoto Chemicals, Inc.

Norihiko Mihara

Tadashi Koike

Tsutami Misawa

Akira Ogiso

Taizo Nishimoto

Hisashi Tsukahara

Shinobu Inoue

Ryousuke Nara

Shunsuke Murayama

An optical recording medium having a recording layer which contains at least one compound selected from the group consisting of mono-, di-, and triazaporphyrin compounds optionally in the form of a metal complex; or an optical recording medium comprising a substrate and formed thereon at least a recording layer containing an organic dye as a main component, characterized in that the organic dye has a first maximum value of absorption at a wavelength &#x3bb;of 400 nm or less in the absorption spectrum and has a second maximum value of absorption at a longer-wavelength side than the &#x3bb;, and a wavelength band wherein the refractive index (n) and the absorption coefficient (k) of the above organic dye satisfy n&#x2267;1.90 and 0.03&#x2266;k&#x2266;0.30.

Optical recording medium and novel azaporphyrin compounds

An optical recording medium comprising a recording and a metal reflective layers on a transparent substrate having a groove, wherein the recording layer comprises an azaporphyrin metal complex dye with 1 to 4 meso-nitrogen atoms as a main component; recording and/or reproduction can be conducted using laser beams with wavelengths of &lgr;1 and &lgr;2 which is shorter than &lgr;1; a refractive index n of the recording layer is 2.0 or more at &lgr;1 and 1.8 or more at &lgr;2 as well as an attenuation coefficient k of the layer is 0.04 to 0.20 at &lgr;1 and 0.30 or less at &lgr;2; and the groove has a pitch of 0.70 to 0.85 &mgr;m, a half-value width of 0.20 to 0.35 &mgr;m and an inclination angle of 45 to 65&deg;:

Optical recording information medium

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Sodegaura, Japan

Norihiko Mihara