An optical disk is provided for recording data of a signal modulated according to a predetermined modulation method in a form of concavo-convex pits. The optical disk includes a first area having a reflecting film partly removed, and a second area for recording pits which are different from pits satisfying...http://www.google.com/patents/US7099245?utm_source=gb-gplus-sharePatent US7099245 - Optical disk, and method and apparatus for reproducing information recorded in optical disk
