Focus control apparatus for use with an optical disk for determi

Focus control apparatus in multi-layered disk reading apparatus

Focus control device and method for use in multilayer optical di

Focus control device for use with an optical pickup comprising a

Focus control device of an optical disk apparatus

Focus control device to perform focus control for a multi-layer

Focus control device to perform focus control for a multi-layer

Focus control for optical disk unit

Focus control for optical scanner

Focus control method and focus controller

Focus control method, and optical disk unit with focus offset co

Focus control system

Focus controlling apparatus and method, and optical disc drive

Focus detecting optical head

Focus detection mechanism and optical head and optical storage d

Focus detection system for an optical disk drive using photo sen

Focus detector which serves to split off a portion of a detected

Focus draw-in system for optical disc device

Focus drive circuit and focus search method based on relative po

Focus error detecting device