Koninklijke Philips Corporation N.v.

Johannes Cornelis Norbertus Rijpers

Guo-Fu Zhou

Roel Van Woudenberg

Erwin Rinaldo Meinders

Guofu Zhou

Hermanus Johannes Borg

Jan Johannes Van Den Broek

Antonius Emilius Theodorus Kuiper

Mark Van Schijndel

Hermanus Henricus Josephus Wilting

Johannes Henricus Jocephus Roosen

A multi-stack optical data storage medium for rewritable recording by a focused laser-light beam, the medium having a substrate with deposited on aside thereof:

Multi-stack optical data storage medium and use of such a medium

The optical data storage medium () has a substrate () with a surface area having tracks () of marks representing stored information. The information is readable by means of a scanning radiation beam (). A reflective layer () is present, reflecting the radiation beam (). The medium has a radiation beam () reflection larger than 50%. The reflective layer () comprises a compound of the formula Al,X, in which formula Al is aluminum and X is an element selected from the group of Ge and Si. The letter y is the atomic fraction of X in at. %. The value of y is in the range 5&#x3c;y&#x3c;35. The reflective layer () has a radiation beam absorption, which enables controlled ablative recording or solid-phase change recording of an identification mark (').

Optical data storage medium and use of such a medium

A description is given of a multi-stack optical data storage medium () for rewritable recording using a focused radiation beam () entering through an entrance face () of the medium () during recording. The medium () has a substrate (). Deposited on a side thereof is a first recording stack () with a phase-change type recording layer (). The first recording stack () is present at a position most remote from the entrance face (). At least one further recording stack (), with a phase-change type recording layer () is present closer to the entrance face () than the first recording stack (). A metal reflective layer of Cu, transparent for the radiation beam (), is present in the further recording stack () and has a thickness between 2 and 10 nm. A transparent spacer layer () is present between the recording stacks (). In such a way a metal reflective layer () with a high optical transmission combined with sufficient heat sink action is achieved which furthermore has a low chemical reactivity with adjacent layers.

Multi-stack optical data storage medium and use of such medium

An optical information medium () for erasable recording by means of a laser-light beam () is provided. A substrate () holds a stack () of layers with a phase-change recording layer () between a first dielectric layer () and a second dielectric layer (). A light-absorptive layer () is present proximate the recording layer () and is made of a compound of the formula QR, in which Q is the element Si, Ge, Ti, Zr, Hf, Nb or Ta, R is the element O or N, and 0&#x3c;x&#x2266;2.5, in order to achieve that 0.8&#x3c;A/A&#x3c;1.50, in which Aand Aare the respective quantities of laser-light absorbed in the recording layer () in the crystalline state and the amorphous state at a laser-light wavelength selected from a range of 350-450 nm. Thus high data rates and low data jitters are achieved at this short wavelength range by tuning x to an optimal value during manufacture of the optical information medium.

Optical information medium and its use

A description is given of multi-stack optical data storage medium () for rewritable recording by means of a focused laser-light beam (), said medium () having a substrate () with deposited on a side thereof: a first recording slick () comprising a phase-change type recording layer ()- at least one further recording stack () comprising a phase-change type recording layer (),- a transparent spacer layer () adjacent each further recording stack (). The further recording stack () is sufficiently transmissive to ensure proper sensitivity for reading and recording in the first recording stack (). For this purpose, at least one heat sink layer () made of HfNx, and 1.1=&#xd7;=1.6, is present in at least one of the recording stacks (). The heat sink layer () further ensure proper cooling behavior of the recording layer () of the further recording stack () in order to obtain sufficient recording performance in the further recording stack ().

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Eindhoven, Netherlands

Johannes Cornelis Norbertus Rijpers