蓝光高密度光盘驱动器中聚焦误差特性分析

高密度数字视盘(HD-DVD)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HD-DVD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HD-DVD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 关键词： 光存储 刀口法 聚焦误差 标量衍射

Analysis of the focus error characteristic in high density optical disk driver

High density digital video disc (HD-DVD) is one of the high density optical data storage technologies to meet the demand of high definition TV. The knife-edge method for focus error detection in HD-DVD driver is proposed in this paper. The calculation model for optical intensity distribution on photo detector under different defocusing amount is deduced on the basis of Fresnel formula and scalar diffraction theory.The S curve obtained theoretically showing how the focus error intensity varies with defocusing amount is in agreement with the experimental one for HD-DVD driver,which validates the calculation model.Furthermore, the focusing noise caused by pit-modulation in HD-DVD driver is analyzed and indicated to be less than 4.5%. It is concluded that a satisfactory focus range of linearity is realized in HD-DVD driver with knife-edge method which has high sensitivity and low focusing noise.