Improvement of dynamic characteristics for optical pickup actuator using sensitivity analysis

The disk rotation speed of optical disk drives (ODD) has been increasing rapidly to achieve high data transfer rates. High servo bandwidths for focusing and tracking actuator are required to follow dynamic disturbance by high rotation speed in ODD. However, the servo bandwidth is significantly limited by some vibration modes which are induced by the flexibility of the moving part. In this work, the vibration modes affecting the bandwidth of actuators are shifted to high frequency range and suppressed by modifying the FE model which is used to analyze the motion of the actuator. Some local dimensions of the lens holder, which is included in the moving part, are selected as design variables to increase the stiffness without changing the material properties. Selected modal frequencies of the moving part are raised about 10%, while the performances of actuator such as DC and AC sensitivities are hardly affected by the modification.