Patent ID: 7257052

Claim:
A tracking control apparatus for controlling an optical head comprising a converging part for converging and irradiating an optical beam onto an information storage medium having a first address and a second address shifted from an information track toward the inner radius side and outer radius side by approximately ½ track, respectively to perform optical recording and/or reproduction on the information storage medium, an optical detecting part for detecting reflected light of the optical beam obtained from the information storage medium and a moving part for moving the converging part across the information track, the tracking control apparatus comprising: an address reading part for acquiring addresses recorded on the information storage medium through the output of the optical detecting part; a first address reading deciding part for deciding that the address reading part has acquired the first address; a second address reading deciding part for deciding that the address reading part has acquired the second address; a lens position characteristic measuring part for successively generating offset set values so that the position of the converging part is moved by the moving part at predetermined spatial intervals and counting the number of times the decision results of both the first address reading deciding part and the second address reading deciding part show that the addresses have been acquired; and a lens shift adjusting part for searching for a maximum value of the acquisition count and moving the converging part using the moving part based on the offset set value when the acquisition count reaches a maximum value.