Soo Kyung Kim

Vibration characteristics and birefringence of optical disk considering initial stress

Recently a great deal of effort has been made to increase the data access speed and the data storage density of the optical memory disks such as CD-ROM, DVD, ASMO disk, etc. In the viewpoint of increasing the data access speed of the optical disk, it is of great importance to characterize accurately the vibration phenomena of the rotating disk, which is related to the critical speed and the characteristics of the frequency response. In this paper, we suggest a novel method to improve vibration characteristics of disk without deteriorating optical characteristics. The main idea is that the initial stress in the radial direction is to be imposed within the optical disk on purpose. By the synergy effect from the residual stress frozen in the disk combing the stress induced by the centrifugal force, the stiffness of the disk increases to have stronger resistance to disturbance, resulting in increasing critical speed. In order to enhance the synergy effect, parametric modifications related to the disk design and manufacturing were presented and evaluated. Based on the computer simulation and experiments, we verified the suggested ideas that it clearly improves the vibration characteristics of disk.