| 摘要 |
PURPOSE:To increase recording density by providing >=2 layers of recording films to a recording medium in the thickness direction thereof and providing a 2-wavelength sepn. film which can separate >=2 laser beams having different wavelengths between the respective recording layers. CONSTITUTION:This recording medium is constituted of a substrate S, the recording film B, the 2-wavelength sepn. film C, and the recording film A, successively from a light incident side. The film C has the characteristic to allow transmission of the light beam Lb of, for example, wavelength lambda1 and reflects the light beam Mb of wavelength lambda2. A light spot L is eventually projected onto the film A and a lambda2 light spot M onto the film B, respectively. The two light spots are disposed in proximity to each other in the direction perpendicular to tracks on both the recording films in such a manner that the spacing between the centers thereof is equal approximately to the track pitch. The lambda1, lambda2 recording pits recorded by the two light spots are thereby formed alternately closely to each other in the direction perpendicular to the tracks, by which the recording density is doubled as compared to a single-layered medium.
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