An optical disk has a recording track constituted by sectors arranged in a concentric or spiral form. Each sector is divided into segments, and each segment includes a data field where data is recorded and a clock mark field having a different light reflectance from that of the data field. The data field...http://www.google.com/patents/US6909677?utm_source=gb-gplus-sharePatent US6909677 - Optical disk, optical reproduction device, and optical recording device
