Abstract: A multilayer optical recording medium including at least multiple information layers each having at least a phase change recording layer capable of recording information by laser irradiation and a reflection layer, wherein each information layer other than the innermost information layer as seen from a side of the laser irradiation has at least a lower protection layer, the phase change recording layer, an upper protection layer, the reflection layer and an optical transmission layer, the upper protection layer and the optical transmission layer in each information layer other than the innermost information layer as seen from the side of the laser irradiation are composed of an Sn oxide-containing material and a thickness of the upper protection layer in each information layer other than the innermost information layer as seen from the side of the laser irradiation is 2 nm to 15 nm is provided.

Abstract: The present invention relates to a high data density optical recording medium. The invention further relates to an apparatus for reading from such an optical recording medium. The optical recording medium has marks that are arranged in tracks. The tracks have a cross section with a curved shape and protrude above a surface of the optical recording medium.