| 摘要 |
PURPOSE:To raise the convergence of an optical beam, and to execute recording and reproduction by the optical beam of a low output, by forming a bottom face shape of a groove part consisting of a groove or a pit provided on the surface of an optical disk, to a projecting shape. CONSTITUTION:A resin layer 2 having optical transmission property is provided on a light transmittable substrate 1, a groove part 3 consisting of a continuous grooves or pits is formed on said layer, and a recording material 4 is coated on the rear side of the substrate 1. Also, the shape of the bottom face of the groove part 3 is formed to a projecting shape. Accordingly, when an optical beam has been irradiated, a condensing action is generated by a lens effect of the groove part 3, and it is further converged than the beam waist diameter of the optical beam and irradiated. Therefore, the virtual sensitivity of a recording material 4 is improved, and recording or reproduction can be executed by the optical beam of lower output than usual. |
