AUTOMATIC DETECTOR FOR OPTICAL DISK PREFORMAT PART

PURPOSE:To obtain a device to automatically detect a preformat position by binarizing the difference in the reflection factor of an optical disk, calculating the data of an angle from the reference position of a spindle, and statistically processing the data. CONSTITUTION:The optical disk 1 is rotated and a reflected beam is binarized by a binarizing means 11. Then, the output of a position data reading means 12 is read out by the rise of an output pulse from the means 11. For each position data, the ideal preformat position is calculated with the position data of its own optical disk as a reference. Next, standard deviation is calculated from difference between the ideal position of preformat and a really measured position. Out of the respective diviations, the minimum deviation is extracted and out of the ideal preformat positions calculated from the position in the case of the minimum deviation, for a value most approximate from the spindle reference position, the preformat position is offset. Thus, the preformat position can be automatically detected and it is not necessary to always monitor or operate an optical disk inspecting device.