Layer-jumping and focusing control method
In a layer jump and focusing control method, a first focusing error signal is generated according to the differential astigmatism method in a closed-loop focusing control manner when focusing on the first recording layer. A second focusing error signal is generated according to the astigmatic method...
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| Format: | Patent |
| Sprache: | eng |
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| Zusammenfassung: | In a layer jump and focusing control method, a first focusing error signal is generated according to the differential astigmatism method in a closed-loop focusing control manner when focusing on the first recording layer. A second focusing error signal is generated according to the astigmatic method in an open-loop focusing control manner when a first layer-jumping procedure is performed to shift a focusing position from the first recording layer to the second recording layer. Then, the completion of the first layer-jumping procedure is determined according to the second focusing error signal, for example when the second focusing error signal passes the zero crossing point and exceeds a threshold level. Afterwards, a third focusing error signal is generated according to the differential astigmatism method in a closed-loop focusing control manner when focusing on the second recording layer. |
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