| 摘要 |
PURPOSE: To preform the recording, the reproducing and the erasing of informa tion on both of groove parts and intergrooves of a substrate by making the depth and the width of the groove and the interval between grooves prescribed dimensions. CONSTITUTION: In an optical recording medium in which grooves are formed, (1) the depth (d) of grooves 4 is made to be λ/7n<d<λ/5n (λ: the wavelength of an irradiating light. n: the refractive index of the substrate). (2) moreover. when the width of grooves 4 and the interval between intergrooves are respectively defined as GW and LW, GW and LM are made to be larger than 0.1μm and also are made to satisfy (3) GW<LW and (4) 0.62×(λ/NA)<=LW<=0.80×(λ/ NA) (NA: the numerical aperture of a lens) to use both of grooves 4 and intergrooves (land parts) 3 as recording areas. |
