A High-Stiffness Optical Head For Quick Access And Precise Tracking Servo

An optical head for quick access and precise tracking servo has been developed. The head uses two independent one-dimensional lens actuators and a pair of relay lenses, instead of the conventional galvano mirror or two-dimensional lens actuator. This simple device is suitable to widen the higher-order resonance frequency and to apply the two-stage radial srevo which increases the tracking servo gain and range. The relay optics reduces the offset error caused by the deviation in the reflected back beam on 100 μm tracking to less than 0.1μm and enables the light source and detection parts to be separated from the positioner drive which carries only the lens actuators for access.