Abstract: There are provided a thermal printing layer capable of thermal printing with a thermal head, and an optical recording medium. It is a thermal printing layer capable of thermal printing with a thermal head, which comprises a heat-sensitive color development material, a developer, and a curable resin, wherein the curable resin has an elastic modulus of 1000 Pa or more at 30° C. and an elastic modulus of 1100 Pa or less at 150° C. Also, it relates to an optical recording medium comprising the thermal printing layer and a recording/reading functional layer for performing recording or reading with a light, wherein the optical recording medium has the thermal printing layer on a side of the recording/reading functional layer in which the side is opposite to a side on which the light enters.

Abstract: In an optical recording method used when information is recorded in a phase-change recording layer of a large-capacity rewritable optical recording medium such as a DVD-RW, one block pulse is used as a recording pulse for forming one recording mark when a recording velocity is higher than a recording linear velocity at which the rewritable optical recording medium can be rewritten, whereas a pulse train comprised of a plurality of short pulses is used as the recording pulse for forming one recording pulse when the recording velocity is within recording linear velocities at which the rewritable optical recording medium can be rewritten, whereby high-velocity recording is realized.

Abstract: An optical recording medium simultaneously having higher recording characteristics and storage stability than ever, is obtained. An optical recording medium comprising at least a phase change recording layer, a first diffusion preventing layer, a second diffusion preventing layer and a protective layer formed in this order on a substrate, characterized in that the first diffusion preventing layer and the second diffusion preventing layer comprise a non-gas element and nitrogen and/or oxygen as the main components, the non-gas element in each of the first diffusion preventing layer and the second diffusion preventing layer, is the same, and the content (atomic %) of nitrogen and/or oxygen contained in the second diffusion preventing layer, is larger than the content (atomic %) of nitrogen and/or oxygen contained in the first diffusion preventing layer.

Abstract: An optical recording medium includes a plane ring-shaped substrate in which a center hole is opened at the center thereof, a recording-retrieving function layer and a cover layer each having an outer diameter approximately equal to that of the substrate and an inner diameter larger than an outer diameter of the center hole, are stacked on the substrate, and as a separate entity from the cover layer, a clamp portion which is for holding and fixing the substrate and which has an outer diameter smaller than inner diameters of the recording-retrieving function layer and the cover layer, is provided around the center hole in a region where the cover layer is not formed.