| 摘要 |
PURPOSE:To reduce the mass mounted on each driving system and to reduce a moment of inertia to perform quick access by separating an optical head and the driving system of an electromagnet for external magnetic field from each other. CONSTITUTION:A magnet driving system 13 of an electromagnet 4 for external magnetic field which is moved synchronously with the moving locus of an optical head 2 is provided independently of an optical head driving system 7. Plural optical heads 2 and 3 are arranged in the optical head driving system 7 to face each other with two disk between them so that emitted beams of heads face each other, and electromagnets 4 and 5 for external magnetic field are set to one arm back to back and are arranged to pair with plural optical heads 2 and 3 respectively. Thus, the access time is shortened. |
