Patent ID: 7247417

Claim:
An optical recording medium capable of being recorded and/or reproduced thereon with light of 390 to 420 nm incident upon a light transmitting layer surface, comprising at least: a supporting substrate; a recording layer on the supporting substrate, the recording layer containing an organic compound as a major component; a dielectric layer on the recording layer; and a light-transmitting layer on and directly in contact with the dielectric layer, the light-transmitting layer having a thickness of 1 to 150 μm and being capable of transmitting laser light with a wavelength of 390 to 420 nm for recording and reproducing information, wherein the organic compound in the recording layer includes a trimethine cyanine dye that has the minimum value n min of its refractive index n (real part of the complex refractive index) within the range of 370 to 425 nm and has a refractive index n of 1.2 or lower with respect to the wavelength of the recording/reproducing laser light, and the organic compound, when absorbing the laser light, melts or degrades to bring about a change in the refractive index, thereby effecting recording of the information and wherein the trimethine cyanine dye contains a trimethine chain with two nitrogen-containing heterocyclic rings positioned on ends of the trimethine chain, one of the two nitrogen-containing heterocyclic rings being benzoxazole and the other of the two heterocyclic rings being selected from the group consisting of benzoxazole, benzimidazole and indolenine, wherein lands and grooves are formed on the supporting substrate with the grooves being 60 to 150 nm in depth, and having a pitch of 290 to 350 nm wherein only the land area serves as a recording area.