| 摘要 |
PURPOSE:To attain the output of all reproduction signals, address signals and servo signals with high quality by providing a guiding groove part and a signal pit part showing an address of another guiding groove having smaller width than said guiding groove. CONSTITUTION:A pit part 13 for address signal showing a guiding groove 12 as well as the groove 12 are formed on a substrate of glass, etc. The pit width t1 of the part 13 is smaller than the width t2 of the groove 12. Such groove width is obtained by changing the laser power in a recording mode. In case the width t1 is large, a light spot is covered entirely within the pit. Thus no pit is substantially obtained and therefore no signal of high quality is not obtained. Here the information signal pit is set larger than the beam diameter. Thus it is possible to output all address signals, information signals and servo signals with high quality. |
