Patent ID: 7800987
Filing Date: 2010-09-21
Classification: G11B

Abstract:
1. An optical pickup driving apparatus for focusing an optical spot on a single-layer recording surface or a plurality of multi-layered recording surfaces of an optical information recording medium, comprising: moving means of moving an objective lens for focusing said optical spot on said recording surface of said optical information recording medium in a direction of the optical axis of said optical spot; and control means of controlling said moving means based on a voltage of a focus error signal based on reflected light from said optical spot, wherein said control means controls said moving means so that said moving means moves said objective lens toward said recording surface, and when said control means detects that the voltage of said focus error signal has reached a first slice level voltage corresponding to displacement of predetermined magnitude from a reference potential, said moving means moves said objective lens toward said recording surface by a maximum of an upper limit of a predetermined amount of movement, and when the amount of movement of said objective lens has reached said predetermined amount of movement, said moving means moves said objective lens away from said recording surface, and when said control means newly detects that the voltage of said focus error signal has reached a second slice level voltage corresponding to displacement of predetermined magnitude from said reference potential before the amount of movement of said objective lens reaches said predetermined amount of movement, said control means controls beam spot positioning so as to focus the optical spot.