Patent ID: 7054240
Filing Date: 2006-05-30
Classification: G11B

Abstract:
1. A system for providing focus control in a multi-layer optical storage medium, comprising: a light source that generates a beam of light; an optical disk having a first and a second optical layer, the optical disk reflects the beam of light off one of said first and said second optical layers; a detector for receiving the reflected beam; a controller circuit coupled to the detector, said control circuit to provide a servo signal in response to said reflected beam; a conditioning circuit coupled between said detector and said controller, said conditioning circuit to provide a focus signal to said controller circuit based on said reflected beam; a gain circuit and a hold circuit, said gain circuit to provide an output signal representing current servo information and said hold circuit to provide an output signal representing predetermined servo information, wherein said controller selects one of said output signals as said servo signal based on said focus signal; and a driver circuit coupled to said controller circuit and said light source, said driver circuit to direct said light source to move from a first position to a second position based on said servo signal, so as to focus said light source from one of said first or said second optical layer to another one of said first or said second optical layer.