Analysis of Diffraction Efficiency of the Holographic Optical Elements in VCD and DVD
VCD和DVD用全息光栅衍射效率的分析

In VCD and DVD pick-up head systems,the number of the optical elements in a holographic optical pick-up head is less than that used in the conventional one due to the application of holographic optical elements.The principles of the signals detecting,focusing and tracking of the optical disk are analyzed.The general fomulas of the diffraction efficiency for gra- tings are deduced,especially for the gratings with rectangular relief profile.The useful depths between land and groove of the gratings used in VCD and DVD are also given.