Vibration imparted focus search devices in an optical type disc playback device

摘要

A focus search device in an optical type disc playback device comprises an optical system for reading a signal of an optical type disc such as a video disc and a digital audio disc, an optical system moving device for moving the optical system compulsorily in a focusing direction to a focus servo range and a vibration imparting device for imparting vibration to a sliding portion of the optical system such as an object lens while the optical system is being compulsorily moved. Vibration applied to the sliding portion of the optical system puts a shaft and a bearing supporting the optical system in a vibrating state thereby facilitating the movement of the optical system and preventing occurrence of a stick slip.