Optical recording medium and optical recording method

Abstract

An optical recording medium of phase change type wherein favorable recording/reproducing properties are realized in high density recording, in particular, when the minimum mark length is up to 0.6 μm and the track pitch is up to 0.7 μm is provided. An optical recording method wherein high transfer rate is realized in the use of such high density recording medium is also provided. The optical recording medium has a recording layer having a thickness dr of 10 to 18 nm, and the first dielectric layer comprises one or more unit dielectric layers and the number of the unit dielectric layers is m (m: an integer of 1 or more). The relation: λ 2 ≤ ∑ i = 1 m ⁢ n i ⁢ d i + n r ⁢ d r ≤ 3 ⁢ λ 4 is satisfied when i-th unit dielectric layer from the substrate has a thickness of di and a refractive index of ni at the recording/reproducing light wavelength of λ, and the recording layer in its crystalline state has a refractive index of nr. The second dielectric layer has a thickness D in the range of 10 to 50 nm.

Dependencies are inferred from the claim text.