| 摘要 |
PURPOSE:To enable returning to a light recording area in a short time even when an optical head comes off the light recording area by mistake in a seek operation thereof by arranging a pattern of detecting a seek error value on an outer circumference part adjacent to an optical recording part of an optical card. CONSTITUTION:In an optical card 1, patterns 4 of detecting seek errors are arranged at four points vertically at left and right end parts within a recording area 2 where seeking is made. The patterns 4 of detecting seek errors each comprise a part 5 with a reflection factor differing from a recording layer with the width thereof expanding as it separates from the recording layer 2 and a part 6 with the reflection factor the same as that of the recording layer. When the head comes off the recording area and moves onto the seek error patterns 4, (for example, when it moves over to the position B), the head tries to withdraw AT, but the AT can not be withdrawn because of the absence of a track. Then, when an actuator of the head is vibrated in the direction vertical to the track, a signal of a specified pattern from the pattern different in reflection factor. This enables the moving of the head inside the card 1 based on the signal. |
