Image Number 10 for United States Patent #6700862.
The width and/or depth of guide grooves on the disc substrate surface are changed in each data recording layer and the guide groove depth of the recording film layer is appropriately shaped in each data recording layer to provide a high density, high recording capacity optical disc. The optical disc has plural substrate layers each having plural guide grooves; plural data recording layers laminated on the substrate layers, each of the plural data recording layers having a recording film for recording data over the guide grooves; and an intermediate layer between the plural data recording layers. The guide groove width is different on each substrate layer. The guide grooves of the data recording layers formed according to the guide grooves of the substrate layer have the same pitch in each data recording layer.