Abstract: An optical disk with multi-layered structure provided with at least two recording layers is provided. In respective recording layers, tracks are formed, and the track is formed such that the amount of eccentricity is different in respective recording layers. In the method for identifying the recording layer which identifies the recording layer of the optical disk, the recording layer is identified by detecting the amount of the eccentricity set to the track of the respective recording layers.

Abstract: An optical disc comprises; a substrate; grooves concentrically or helically formed on the substrate in each of which data is recorded; lands defined between the adjacent grooves; and prepits formed on the lands, wherein each of the prepits is disposed to be shifted from a center line of the land toward a groove to be paired without overlapping with adjacent tracks, whereby reducing cross-talk from adjacent tracks and improving the density of recorded data.

Abstract: An optical disc comprises; a substrate; grooves concentrically or helically formed on the substrate in each of which data is recorded; lands defined between the adjacent grooves; and prepits formed on the lands, wherein each of the prepits is disposed to be shifted from a center line of the land toward a groove to be paired without overlapping with adjacent tracks, whereby reducing cross-talk from adjacent tracks and improving the density of recorded data.

Abstract: An optical disk original recording is formed as follows: In a photo-resist layer forming step, a photo-resist layer is formed in such a manner that its thickness is much larger than the thickness which corresponds to a predetermined depth; and in a heating step, the photo-resist layer is heated at a temperature close to the melting point thereof, so that the surfaces of the recesses are fluidized to eliminate the rough surfaces, and the thickness of the photo-resist layer is decreased to a value which corresponds to the predetermined depth of the pits or grooves.

Abstract: In a method for manufacturing a master disc for optical discs, patterns to be displayed on the disc are classified into a main object and a background. The background is commonly assigned as the background pattern for glittering rainbow colors by diffracted light reflected from dummy pits of diffraction gratings or a hologram. The main object is individually assigned as the main object pattern of a diffused reflection portion or mirror surface. The manufacturing method comprises one group of steps for forming the common background pattern and the other group of steps for forming the individual main object pattern in the common background pattern. A development substrate for the master disc is formed by using a mask disc in a first light-exposure of a photoresist layer thereof and by using a displaying-pattern mask in a first light-exposure of the photoresist layer. The individual main object pattern is drawn in the common background pattern of the master disc by using a laser-marking or an etching.

Abstract: An optical disk in which a pattern such as a character that can be recognized is displayed in an information recording area by display pits or grooves formed between recording tracks constructed by pit trains indicative of information signals. An apparatus for manufacturing the optical disk in which information and display modulation light beams obtained by modulating a light beam in accordance with pattern signals for information and display, respectively, are separated from each other in the disk radial direction and are simultaneously irradiated to a resist layer formed on a recording surface of a disk.

Abstract: An optical disk having both recording surfaces on which are formed pits trains. A recognizable display pattern is formed by a group of dummy pits formed on one of the recording surfaces. An apparatus for manufacturing the optical disk in which a light beam is modulated in accordance with a dummy forming signal obtained by selectively stopping a dummy pulse, and the modulated light beam is irradiated to a resist layer formed on a recording surface of a disk to form a group of dummy pits representing a display pattern.

Abstract: An optical disc is provided with: a disc substrate of light transmissive type having an information record surface including an information recorded region, where pits or grooves carrying an information signal are coaxially or spirally formed, and an information not-recorded region, where the pits or grooves carrying the information signal are not formed; a light reflective layer wholly disposed on the information record surface in the information recorded region, and partially disposed on the information record surface in the information not-recorded region such that an indication pattern is formed of the partially disposed light reflective layer on the information record surface in the information not-recorded region; and a protection layer disposed on the light reflective layer and a portion of the information record surface in the information not-recorded region where the light reflective layer is not disposed.

Abstract: A method and implementing apparatus for electroless plating an optical disk causes the disk to be positioned in a container with its main surface upturned and then rotated. As the disk rotates, liquid for treating or cleaning the disk is caused to fall on the upturned main surface from a position above the disk.