Abstract: A disc playback apparatus is configured to reproduce information by demodulating and decoding a radio-frequency signal obtained by receiving reflected light of a beam applied to a recording surface of a removable disc when the disc is loaded in the disc playback apparatus. The apparatus includes a disc format determining unit adapted to determine the format of the loaded disc, a high-frequency compensation unit adapted to compensate for a high-frequency component of the radio-frequency signal, a low-frequency compensation unit adapted to compensate for a low-frequency component of the radio-frequency signal, and a control unit adapted to determine which of the high-frequency compensation unit or the low-frequency compensation unit is to be used to compensate for a frequency characteristic of the radio-frequency signal based on the determined disc format.

Abstract: A disc playback apparatus is configured to reproduce information by demodulating and decoding a radio-frequency signal obtained by receiving reflected light of a beam applied to a recording surface of a removable disc when the disc is loaded in the disc playback apparatus. The apparatus includes a disc format determining unit adapted to determine the format of the loaded disc, a high-frequency compensation unit adapted to compensate for a high-frequency component of the radio-frequency signal, a low-frequency compensation unit adapted to compensate for a low-frequency component of the radio-frequency signal, and a control unit adapted to determine which of the high-frequency compensation unit or the low-frequency compensation unit is to be used to compensate for a frequency characteristic of the radio-frequency signal based on the determined disc format.

Abstract: A head feeding mechanism used for an apparatus for recording and/or reading information signals on/from such a recording medium as an optical disk comprises a head mechanism, a feed screw, a rotation driving mechanism, a base, and a forcing mechanism. The feed screw is engaged with the head mechanism and rotated to feed the head mechanism. The rotation driving mechanism drives the feed screw to rotate. On the base is arranged the rotation driving mechanism. The base includes a pair of bearings used for the feed screw. At least one of the pair of bearings is a thrust bearing. The forcing mechanism is provided on the base and butts against one end of the feed screw. The forcing mechanism applies a force working on the feed screw both in the thrust direction and in the direction orthogonal to the thrust direction.

Abstract: An objective lens driving device employed for a recording and/or reproducing apparatus for an optical recording medium includes a bobbin on which an objective lens is mounted, a supporting mechanism, first and second coils and a magnetic circuit. The supporting mechanism supports the bobbin in at least one of a first direction parallel to the optical axis of the objective lens and a second direction perpendicular to the optical axis. The first coil is provided on the bobbin and is mounted so that at least its one coil side is substantially perpendicular to the first direction. The second coil is provided on the bobbin and is mounted so that at least its one coil side is substantially parallel to the first direction. The magnetic circuit has a pair of magnets facing each other with a pre-set gap in-between. The first and second coils are arranged in the gap and plane-symmetrically with respect to the centerline of the gap.

Abstract: An optical pickup device employing an objective lens driving device for displacing an objective lens relative to an optical disc surface in directions parallel and normal to the optical axis of the objective lens. The objective lens is mounted in a movable part consisting of a bobbin having an opening at its mid portion. A plurality of resilient supporting members movably support the movable part. A magnetic circuit unit includes a flat-plate-shaped member carrying a focusing coil and a tracking coil. The flat-plate-shaped member extends parallel to the optical axis of the objective lens. The focusing and tracking coils drive the movable part in a direction parallel to, and in the planar direction normal to, the optical axis of the objective lens. An objective lens driving device is mounted for translating movement on a base member on which are mounted a light source, a light receiving element (for receiving return light), a reflective mirror, and a beam splitter.