Yukinobu Abe

Development of Cooling Structures for Blu-Ray Disc Compatible Optical Disc Drives Using Computational Fluid Dynamics Based on Cartesian Grid Method

High-performance, simple cooling structures for optical disc drives compatible with the Blu-ray disc (BD) were developed using unsteady numerical flow simulation based on the Cartesian grid method. In the new structure, an additional hole in the tray outside of the disc induced a secondary upward flow, which is caused by a pressure difference and rotating-disc flow. The secondary flow decreases the ambient air-temperature of the laser diode below the hole, and furthermore it increases the velocity around the laser diode and enhances the heat transfer rate. The experimental results indicate that the cooling effect of the laser diode increases, and the disc vibration is not influenced by the additional hole in the tray. The cooling structures are applied to the so-called super-multi BD drive, which achieved 4X high-speed recording for the first time in the industry.Copyright

Basic Characteristics and Predicted Lifetime of Stacked Volumetric Optical Disks

A stacked volumetric optical disks (SVOD) system has been developed to achieve an over 1 Tbytes cartridge capacity using a commercialized drive and conventional recording layers. To confirm the reliability of thin optical disks in SVOD, several feasibility tests were conducted. The recording power margin, tilt margin and read stability of the thin optical disks were measured, and the lifetime of the thin optical disks was estimated. The results were similar to those of conventional 1.2-mm-thick optical disks regardless of the disk thickness.

Investigation of Airflow Velocity Distribution in Hard Disk Drives Using LES and PIV

This paper deals with the specific tools necessary to investigate airflow in HDD with the aerodynamic parts. The simulation modeling of HDD is made by using large eddy simulation (LES), which covers most of the configuration between the two co-rotating disks, including the arm assembly and effective methods for investigating the airflow inside an actual HDD, namely, particle image velocimetry (PIV) with tetrahedral elements.