| 摘要 |
PURPOSE:To enable sure tracking as well as recording and reproduction by forming pregrooves and prebits so as to have surface rugged structures. CONSTITUTION:Plural pieces of the regular surface-rugged structures having the repetitive length which is the same as the wavelength of laser beams or larger than the same are imparted into the pregrooves. The reflected light rays of the light projected to the pregrooves, therefore, interference with each other not only in the boundary regions on the outermost part of the pregrooves but also in the boundary regions of the ruggedness in the pregrooves, by which the intensity thereof is decreased; further, said light rays interfere with the reflected light as well on the outside of the pregrooves so that the quantity of the reflected light is additionally decreased. The effective and sure information on tracking is thereby obtd. |
