| 摘要 |
A super-resolution optical head device in which a first super-resolution spot having a diameter smaller than that of a diffraction limit is formed on a recording medium (7) by modulating beams emitted from a laser light source (1) includes an optical system (12,15), an optical separator (13;21;25;27;28;31,21), and a plurality of optical detectors (14,16;22a,22b). By the optical system (12,15), the laser beams reflected from the recording medium (7) are converged and a second super-resolution spot is reimaged. The optical separator is constituted by a reflection-type pinhole (13), a diffraction-type pinhole (21), a refraction-type pinhole (25), a reflection-and-absorption type pinhole (27,28), or a set of a reflection-type pinhole (31) and a reversed-type pinhole (32), which is placed at the reimaged position and optically separates the second super-resolution spot into a main beam component and a sidelobe component. The optical separator leads to the optical detectors (14,16,22a,22b) the main beam component and the sidelobe component independently from each other. The device enables to easily obtain reproduction signals with little deterioration caused by the sidelobe component. <IMAGE> |
