An information recording medium having at least a read only area and a recording and reproducing area is composed of at least: a substrate; a recording layer formed on the substrate so as to record and reproduce information; and a light transmission layer having transparency formed on the recording layer....http://www.google.fr/patents/US7675839?utm_source=gb-gplus-shareBrevet US7675839 - Information recording medium having a wobbling groove structure
Information recording medium having a wobbling groove structure
