| 摘要 |
PURPOSE:To use two beams of laser light so that information can be written to other guide grooves by the other beam while guide grooves are initiated by one beam by forming the spiral guide grooves toward the center of rotation and preliminarily forming plural pieces of the guide grooves at the time of recording the information along said grooves. CONSTITUTION:A disk substrate made of an epoxy resin or the like which is a replica is formed by using a substrate preliminarily provided with the guide grooves on the surface by coating a photoresist on the surface of disk- shaped glass and projecting and exposing the laser light spirally thereto, then developing the resist. A magnetic recording material film consisting of TbFeCo, etc., is then formed by sputtering on the surface thereof. Two lines of the guide grooves 2a, 2b are formed to the optical disk obtd. in the above-mentioned manner. Overwriting is permitted from the first rotation of the disk when a piece of information is recorded in two lines of the grooves if the disk is constituted in the above-mentioned manner. The overwriting at the time of random access is also possible. Further, a transfer rate is improved if recording or reproducing is simultaneously executed by oppositely disposing optical heads oppositely to each other. |
