| 摘要 |
PURPOSE:To improve the reliability of accessing, by moving an optical beam irradiating position to readable position when position information on a storage medium cannot be read at the time of accessing. CONSTITUTION:An optical head 3 is linearly moved on the track of an optical disk 1 rotated and driven by a motor 2 in radial directions. A control circuit 29 reads the content of a track No. register 16 and calculates the difference of an accessing track No. and the read track No. When the difference is less than a prescribed track number and the track No. cannot be read, the control circuit 29 reads a scale No. in a linear motor driving circuit 8 and calculates the difference of the scale No. and another scale No. corresponding to a track No. to be accessed. When the difference exceeds a prescribed range, the control circuit 29 moves a linear motor 4 by a distance equal to the scale value. When a track No. cannot be read, the controlling circuit judges that the optical head 3 is accessed to an unrecorded part and makes the linear motor driving circuit 8 move the linear motor 4 inward to make seek motion. |
