Patent ID: 7660209

Claim:
An optical disk drive for reading and/or writing data from/on a spiral string of tracks having alternating land and groove tracks with a ratio (L/G) of a width (L) of a land track to a width (G) of a groove track being not equal to one, the optical disk drive comprising: a light source for radiating a light beam; a lens for converging the light beam; moving means for moving the lens; a photodetector for generating an electrical signal based on at least a part of the light beam that has been reflected from the optical disk; and a control section for controlling the light source and the moving means, wherein while performing a seek operation by having the lens moved by the moving means such that a target track, where the data should start being read or written from/on the optical disk, is irradiated with the light beam, the control section tries to get a PLL locked by irradiating a previous track, which precedes the target track by one on the spiral string, with the light beam, wherein if the target track is one of the land tracks, the control section tries to get a PLL locked by irradiating a previous groove track, which precedes the target track by one on the spiral string, with the light beam, and if the target track is one of the groove tracks, the control section tries to get a PLL locked by irradiating a previous land track, which precedes the target track by one on the spiral string, with the light beam, and wherein if the ratio (L/G) is less than one, then the PLL is locked while a beam spot of the light beam moves on the groove track, regardless of whether the target track is one of the land tracks or one of the groove tracks.