Methods of calibrating servo signal bias for optical disc
AssigneeMediatek Inc.
InventorsHsin-Chung Yeh, Jia-Hau Lin, Shang-Wei Wu, Jin-Chuan Hsu
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Abstract
Read focus error (FE) bias is calibrated on an embossed area of the optical disc. OPC is then performed with the calibrated servo signal bias to obtain a write power level. Data are written on and read from the optical disc based on the write power level and the calibrated servo signal bias.
Claims20
A method of calibrating servo signal bias for an optical disc, comprising the steps of:
- calibrating the servo signal bias in an embossed area of the optical disc;
- and
- performing optimum power calibration (OPC) with the calibrated servo signal bias to obtain a write power level.
A method of calibrating servo signal bias for an optical disc, comprising the steps of:
- calibrating a read servo signal bias on an embossed area of the optical disc;
- measuring asymmetry information from the embossed area of the optical disc;
- and performing optimum power calibration (OPC) process based on the asymmetry information to obtain a write power level.
A method of calibrating servo signal bias and write power for an optical disc, comprising the steps of:
- writing data on a power calibration area (PCA) of the optical disc using a plurality of test write power levels and servo bias levels;
- measuring EFM (eight-to-fourteen modulation) characteristic curve corresponding to various servo bias levels at different test write power levels;
- calculating a servo bias difference between two servo bias levels corresponding to a predetermined threshold for each test write power level;
- determining the write power level among the test write power levels if the corresponding FE bias difference is within a predetermined range;
- and
- determining an optimum servo bias level according to the two servo bias levels corresponding to the predetermined threshold, thereby writing the optical disc with the optimum servo bias level and corresponding write power level.
A method of manufacturing an optical disc, comprising the step of:
- embossing a reference signal pattern on the optical disc whose physical characters can be obtained by an optical disc drive for optimum power calibration (OPC).
Dependencies are inferred from the claim text.