| 摘要 |
PURPOSE:To make high-density recording possible with a simple device by alternately providing plural pieces of information signal area and servo signal areas on the track circumference of a disc substrate and forming respectively prescribed magnetic films therein. CONSTITUTION:A low-coercive force magnetic film is uniformly formed in the information signal area 2 of a disc substrate 1, and high-coercive force magnetic films corresponding to mutually different frequencies f1, f2 are formed in a stripe shape alternately to f1, f2, f1, f2... from the outside toward the inside in the servo signal areas 3. A servo mechanism is so constituted that the center of the magnetic head travels at the boundaries of the areas f1 and f2. If such disc is revolved at a constant rotating speed and a magnetic head is fed onto the disc surface, the two signals of f1, f2 are induced intermittently by the magnetic head, whereby tracking is accomplished with good accuracy. With such constitution, the high-density recording of a narrow track width is accomplished with the simple device. |
