| 摘要 |
PURPOSE:To improve the recording capacity of an optical disk, by recording information in two lines on one interval between grooves for tracks. CONSTITUTION:Grooves 2 are installed by forming a spiral or concentric uneven pattern by chemical etching, machining, press work, a method which melts and casts the material, another method which presses the half-melted or softened material, etc. Recording parts 3 are prepared to have a width which is sufficient to put two laser beam spots 4 in the direction of width so that two line recording can be made. When such a substrate structure is used, the inside recording part of the two lines of the recording parts between grooves can be tracked by means of the groove installed to this side of the recording part and the outside recording part can be tracked by using the groove installed to the rear side of the recording part. That is to say, by using one tracking groove, two lines of recording parts at both sides of the groove can be tracked. |
