MULTI-LAYER WRITABLE OPTICAL RECORD CARRIER WITH AN OPTIMUM POWER CALIBRATION AREA, AND METHOD AND APPARATUS FOR FORMING OPTIMUM POWER CALIBRATION AREAS ON SUCH A RECORD CARRIER

摘要

A writable optical record carrier (100) comprising a plurality of recording layers LO,..., Ln-1 separated by a spacer material, each recording layer comprising an optimum power calibration area (101,111,121,131) having a first portion (102,112,122) with an average reflection value representative of a recorded layer and a second portion (113,123,133) with an average reflection value representative of an unrecorded layer, a method, and an apparatus for forming optimum power calibration areas on such a writable optical record carrier are presented. The optimum power calibration areas partially overlap such that the optimum power calibration areas of each pair of consecutive recording layers form a step, and the first portions of said plurality of recording layers have the form of a staircase. Each step formed by a pair of consecutive recording layers k, k+1 has a preferred minimum step size.