High Speed Dual-Layer Blu-Ray Recordable Disc Without Silver/Silver Alloy Semi-Reflective Layer

In this paper, a design of dual-layer Blu-ray recordable (DL BD-R) disc without silver or silver alloy semi-reflective layer is introduced. Five potential dielectric reflector materials, including the AlN, BN, Nb₂O₅, TiO₂ and ZnS-SiO₂ are evaluated and tested to compensate the reflectivity of layer 1 after removing the metallic semi-reflective layer. With the help of optical simulation software, reflectivity in both layers could be optimized by fine tuning thickness of each material and the recording performance was examined in each condition. Furthermore, a simplified layer 1 stack was proposed and evaluated. The disc with only Nb₂O₅ layer as semi-reflector in layer 1 can achieve the desired performance of 6× recording speed and provide the benefit of better mass production from the simplified practical film structure point of view.