Design and analysis of two-wire focusing actuator for small-sized ODD with linear VCM type's actuator

Recent advancements in mobile devices have fueled a requirement for information storage systems with characteristics such as subminiature size, low cost, and minimum power consumption. Small optical disk drives could provide a good solution, because their storage media is cheaper than those of hard disk drives or flash memories. In this study, we design and analysis a linear voice coil motor (VCM) type's actuator for the coarse and fine tracking motions and a two-wire spring type's actuator for a fine focusing motion in order to apply them to small-sized optical disk drives of high data capacity. And, we make the mathematical model of a two-wire spring type's actuator and find proper conditions to suppress the tilt motion of the lens holder for various focusing offset positions without sacrificing the sensitivity. Based on them, we design and modify the magnetic circuit and the structural part. Finally, we verify that the designed actuator had the proper dynamic characteristics and that it could be used in small optical disk drives by simulations and experiments.