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高密度数字视盘(HDDVD)是一种新型蓝光存储技术,可以满足数字高清视频节目的播放要求.介绍了用于HDDVD驱动器中的刀口法调焦方案,基于菲涅耳公式和标量衍射理论,推导了刀口法调焦的HDDVD驱动器中聚焦误差信号与离焦量之间关系的计算模型.应用该计算模型,分析了不同离焦量时探测器上光强分布情况.计算得到的聚焦误差信号与离焦量之间的关系曲线与实验测得的“S型”曲线相一致,证明了计算模型的正确性.进一步分析了正焦点时由于记录符调制而引起的聚焦误差的干扰信号,计算结果表明这种干扰的强度小于4.5%.分析表明,HDDVD驱动器中刀口法调焦系统具有良好的线性范围,灵敏度高、受聚焦串扰噪声的影响小,可以较好地满足聚焦伺服的要求.
High-density digital video disk (HDDVD) is a new type of Blu-ray storage technology that can meet the requirements of digital high definition video programs.An introduction to the knife-edge focusing scheme used in HDDVD drives is based on Fresnel’s formula and scalar diffraction theory The calculation model of the relationship between the focus error signal and the defocus amount in the HDDVD driver with blade-edge focusing was proposed.Using this calculation model, the light intensity distribution on the detector with different defocus amount was analyzed.The calculated error signal and The relationship between the defocus amount and the experimentally measured “S-shaped” curve is consistent, which proves the correctness of the calculation model.Further analysis of the interference signal caused by the focus error caused by the recording character modulation at the positive focal point, the calculation results The results show that the intensity of this interference is less than 4.5% .The analysis shows that the knife-edge focusing system in HDDVD drive has good linear range, high sensitivity and small influence of focusing crosstalk noise, which can better meet the requirements of focusing servo.