| 摘要 |
PURPOSE:To approximately equalize the space resolving power of an erase area to that of recorded information bits by using plural light beams condensed to a diameter approximately equal to the size of the recorded information bit and successively projecting plural light beams synchronously with information bits to be erased to erase information bits. CONSTITUTION:When an area to be erased comes into plural erasing circular laser spots 2 by rotation of an optical disk, each laser spot part of plural erasing circular laser spots 2 is projected to the area synchronously. For example, in case that only one recorded bit is erased, only the first laser spot is projected if this one bit is placed in the first laser spot part of plural erasing circular laser spots 2. When this one bit to be erased is moved to the second laser spot part of plural erasing circular laser spots by rotation of the optical disk, projection of the first laser spot is stopped and the second laser spot is projected. Thus, laser spots of plural erasing circular laser spots 2 are successively projected synchronously with one bit to be erased to erase one bit. |
