Nobuo Takeshita

Progressive Differential Push-Pull Method For Dual Layer Blu-ray Disc Recording

Progressive Differential Push-Pull (DPP) method was developed. In case of dual layer Blu-ray disc recording, conventional DPP signal is disturbed by the stray lights reflected from other recording layer and tracking servo sometimes becomes unstable. This paper presents an example of optical head for dual layer Blu-ray Disc recording. Photo detector of the optical head to suppress the influence of stray lights was developed.

Track error detection system with dual phase difference for super-resolution optical ROM disc

This paper presents a track error (TE) detection system for a readout of a higher-density super-resolution optical disc beyond Blu-ray Disc™, unaccompanied by its complication, based on a differential phase detection method. An improvement of quality of TE signal with this system is described on a numerical simulation using experimentally acquired a readout signal of the super-resolution optical disc.