Patent Number: 6,298,020

Title: Focus search method and controller for digital disk

Abstract: A focus search method and a controller for a digital disk overcomes a shortcoming of a conventional focus search method in which a focus search on a specified layer is always performed from the same direction if a layer jump for changing a layer has been improperly performed during reproduction from a digital disk such as a DVD having a plurality of recording layers, thus taking much time for the focus search when the focus search is begun from a point away from a specified layer. A focus direction used for an immediately preceding focus search performed from an initial focus search position at the outer side of two recording layers is stored in a focus direction memory of a focus direction setter. Based on the data stored in the memory and a signal indicating the position of a specified layer received from a layer specifier that instructs a layer jump, a setter for handling an improper focus jump makes settings so that a focus search is started from a side closer to the specified layer by performing a logical operation and a flow processing.

Inventors: Kumagami; Yusuke (Iwaki, JP)

Assignee: Alpine Electronics, Inc.

International Classification: G11B 7/085 (20060101); G11B 7/09 (20060101); G11B 7/00 (20060101); G11B 007/09 ()

Expiration Date: 10/02/2018