Analysis and design of suspension wire in the optical pickup actuator

Abstract

The lens actuator is the important mechanical-electrical component in the optical disk reading/recording system. According to the error signals from the optical pickup reading/writing process, namely the focusing and tracking error signals, the focusing coils as well as the tracking coils are applied the corresponding corrective current (or voltage), thus, the force generated by the current-on coils in the magnetic field will real-time actuate the objective lens to make the focusing spot precisely fall on the disc information track, realizing the data reading/writing. As wire suspension type, the suspension model determines the wire design process. According to the material mechanics, the force distribution on the wires is analyzed and the four wire suspension model is set up, thus, the wire parameters are designated and the natural frequency as well as the static sensitivity of the moving part can be determined. After serial material experiments using Instron 5848 Microtester, better treatment for the wire fabrication is adopted with 1.5 hour aging and sliver cover-layer.Moreover, the actuator with the suspension wire is tested by the laser vibrometer and results show the good performance of the actuator, which proves the feasibility of the suspension model. Although the suspension model is set up on the four wire suspension actuator used in DVD-ROM, it can also be used in the six wire suspension actuator in the HD DVD and Blu-Ray.