Koninklijke Philips Corporation N.v.

Bas Feddes

Jacob Gerrit Nijboer

Paul Weijenbergh

Jakob Gerrit Nijboer

Johannes Hendrikus Maria Spruit

Johannes H M Spruit

The present invention is related to a method and a reading device () for retrieving information from an optical record carrier () in which the read power level of a radiation beam () for scanning the optical record carrier is set in dependence on the read-out speed. The invention is also related to a record carrier for use with such a method and a reading device.

Method and device for retrieving information from an optical record carrier at various reading speeds

A method of recording marks onto an optical disc, the optical disc comprising an information layer, by irradiating the information layer by a pulsed radiation beam, a mark (I. . . I) having a time length of nT, n representing an integer larger than one and T representing the length of one period of a reference clock, being recorded by a sequence comprising m write pulses separated by cooling periods, the write pulses within the sequence being allowed to have different time lengths, the write pulses comprised in sequences corresponding to marks of different time lengths being allowed to have different lengths, m being an integer number given by Floor(n/&#x3b1;), where Floor(n/&#x3b1;) defines the largest integer smaller than n/&#x3b1;, wherein a is an integer number larger than or equal to 2. The method characterized by modifying at least the sequence comprising the longest write pulse such that the longest write pulse is replaced by two write pulses.

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Eindhoven, Netherlands

Bas Feddes