A touch panel includes a light guide plate, a light emitting device, a light sensing module, and a controller. Different back-off times are assigned for delivery verification reports and repair requests, at least two delivery verification reports of one receiver are jointly transmitted within one point-to-point transmission session, and a delivery verification report is transmitted after a completed repair session within the same point-to-point transmission session used by the repair session. The percentage of particles within any 10 \u03bcm band within the range does not exceed about 20% by volume, and the percentage of particles within any two adjacent 10 \u03bcm bands within the range does not deviate by more than about 8% by volume. In one example, the end-effector has a detector for detecting the presence of a wafer. The recording quality is evaluated by reproducing the data recorded nearby before each split data is recorded using a duration and control is performed by reflecting the evaluation result in the laser output so that the recording quality can be maintained satisfactorily over a series of the whole data to be recorded. The free layer may be a single layer of CoFe, Co, CoFeB or CoFeNiB, or may include a non-magnetic insertion layer.