27-4 ランド/グルーブ記録におけるトラックベクトル検出 Track Vector Detection for Land/Groove Recording

We have successfully developed "Track Vector Detection" for enabling tracking-pull-in and track-counting in the one-beam optical head for land/groove phase-change disk. Instead of setting the two-divided optical sensor, we arranged the four-divided sensor in which the division lines are aligned 45 degree to the radial direction for the disk. The differential output of two elements for radial direction is for the tracking signal, and the sum output for tangential direction gets the land/groove judgement signal.