Method and apparatus for determining the number of data layers in an optical disc
AssigneeSunplus Technology Co., Ltd.
InventorWen-Chun Feng
Life of this patent
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Abstract
The present invention provides a method and an apparatus for determining the number of data layers in an optical disc. Firstly, the objective lens of the optical pickup head is controlled so that it moves toward the optical disc. At the same time, a generated SBAD signal is recorded. The number of wave peaks in the SBAD signal is then detected and the number of the data layers in an optical disc is determined according to the detected number of wave peaks in the SBAD signal.
Claims16
A method for an optical disc drive determining data layers in an optical disc comprising:
- adjusting an astigmatism compensated value which is inputted to an astigmatism compensator of the optical disc drive to a predetermined value;
- moving an objective lens of the optical disc drive and generating a detection signal;
- counting the number of wave peaks in the detection signal;
- and
- determining the number of data layers in the optical disc based on the number of wave peaks in the detection signal;
- wherein the predetermined value is between the optimal compensated value SA0 for reading a first data layer L0 and the optimal compensated value SA1 for reading a second data layer L1.
An apparatus for determining data layers in an optical disc comprises:
- an optical pickup head which has an astigmatism compensator, an objective lens and a photo detector, wherein the astigmatism compensator is capable of receiving a astigmatism compensated value;
- an control unit which is connected to the optical pickup head for controlling the objective lens moving, receiving a electrical signal from the photo detector and outputting a detection signal;
- a counter for counting the number of wave peaks appeared in the detection signal;
- and
- a logical operation unit for determining the number of data layers in the optical disc according the counting result of the counter;
- wherein the astigmatism compensated value is adjusted to a predetermined value;
- and the predetermined value is between the optimal compensated value SA0 for reading a first data layer L0 and the optimal compensated value SA1 for reading a second data layer L1.
A method for an optical disc drive determining data layers in an optical disc comprising:
- moving an objective lens of the optical disc drive and generating a detection signal, wherein a plurality of wave peaks are in the detection signal;
- counting the number of wave peaks which have magnitude larger than a threshold voltage;
- and
- determining the number of data layers in the optical disc to be the number of the wave peaks in the detection signal minus 1 when the number of wave peaks in the detection signal is larger than 1.
Dependencies are inferred from the claim text.