| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical information recording/reproducing device suited to recording/reproducing of a 3-dimensional multilayer optical disk and capable of increasing focus detection sensitivity and resolution more than a conventional technology. <P>SOLUTION: The information recording/reproducing device having a light source, an optical system for applying an optical spot, and an optical spot position controller and adapted to control the position of an optical spot applied to a recording medium is provided with pinholes 9A and 9B arranged near the focal points of return lights obtained by dividing a return light from the recording medium into two and converging them, and optical detectors 10A, 10A', 10B and 10B' arranged behind the pinholes. One of the two pinholes is arranged in front of the focal points of the return lights, and the other is arranged behind the focal points of the return lights so that they are slightly apart from each other, and optical spot position is controlled based on the differential outputs of the two detectors behind the two pinholes. <P>COPYRIGHT: (C)2007,JPO&INPIT |
