An optical head which includes a movable bobbin having an objective lens and tracking coils for tracking operation, a carriage guided in such a manner to be able to move in the tracking direction and a state transformation mechanism for transforming the state of the bobbin and carriage between a first state, in which the objective lens can move in the tracking direction but the carriage does not move in the tracking direction, and a second state, in which the movable bobbin and the carriage moves in the tracking direction as one body. When effecting a tracking operation, the state transformation mechanism transforms the state of the bobbin and the carriage into the first state, in which the objective lens can move in the tracking direction but the carriage does not move in the tracking direction, and a tracking drive current is then made to flow through the tracking coils to perform the tracking operation. This results in that the objective lens is supported by a system of a single degree of freedom, of which characteristics are determined by the mass of the movable bobbin and the spring constant of the bobbin supporting means. In contrast, when effecting an access operation, the state transformation mechanism transforms the movable bobbin and the carriage into the second state, in which the bobbin and the carriage move in the tracking direction in one united body, and an access drive current is then made to flow through the tracking coils to effect the access operation. Thereby, tracking performance can be increased and a seeking operation can be performed at a high speed. Further, the tracking coil can be used to effect the access drive operation. Thus, there can be less weight of a movable part of the optical head and lower power consumption.
Conventional disk recording and reproducing apparatuses have addressed a shortcoming that they cannot correct squareness errors and misalignments caused by the warpage of a disk and the eccentricity of the center hole of the disk and of the center of curvature of signal tracks. To overcome this shortcoming, a disk recording and reproducing apparatus of the present invention comprises: magnetic bearing means capable of supporting a rotary body and adjusting a relative position of the rotary body; a pickup for irradiating, with a laser beam, a recording surface of a disk mounted on a table arranged on the rotary body and receiving the laser beam reflected by the recording surface; detection means for calculating a relative positional relationship between the disk and a focal position of the laser beam based on a signal from the pickup; and control means for adjusting the position of the rotary body by controlling the magnetic bearing means.
In an optical semiconductor package according to the present invention, the component bearing surface of the stem having an outline made up of opposed first and second circular-arc parts, a first straight-line part which connects each end of the first and second circular-arc parts and a second straight-line part which connects each other end of the first and second circular-arc parts. The first and second circular-arc parts have a common center, and the first circular-arc part has a larger radius than that of the second circular-arc part. Thus, the larger space, the space between the first circular-arc part and the center, can be used for disposing the light detector or a polarization split element, and the unused space, the space between the second circular-arc part and the center, will be minimum, thereby realizing downsizing and cost reduction of the device.
An electromagnetically controlled drive system for accessing a data storage medium comprises an optical signal generator and a reflector element adapted to receive an optical signal from the optical signal generator. The reflector element is also adapted to direct the optical signal toward the data storage medium. The system also comprises an electromagnetic element adapted to generate an electromagnetic field proximate to the reflector element. The reflector element is adapted to respond to the electromagnetic field to move the optical signal relative to the data storage medium in response to a change in the electromagnetic field.
An apparatus for optically reading or recording information on an optical disc which is rotatable about an axis of rotation. The apparatus includes a frame, a carriage, a carriage drive, an objective lens, an objective lens holder, a focus drive and a fine tracking drive. The objective lens is mounted on the objective lens holder so that the optical axis of the objective lens substantially intersects the center of mass of the carriage. The fine motor, used for tracking and focus, has a center of mass that substantially lies on the optical axis and proximate the center of mass of the carriage.
An optical disk apparatus comprises an optical pickup for directing a light beam onto pits formed in an optical disk and for receiving reflected light from the optical disk, an optical pickup supporting member including two guide rods for guiding the optical pickup in a radial direction of the optical disk, two first mounting members for mounting ends of one guide rod, and two second mounting members for mounting ends of the other guide rod, a chassis for mounting the first and second mounting members, an optical pickup driving mechanism including gears and a motor to move the optical pickup in a radial direction of the optical disk, a turntable on which the optical disk is located, and an optical disk drive motor for rotating the turntable. Each of the first fixing members includes a base fixed to the chassis, a guide rod supporting member for fixedly supporting the guide rod, and a flexible member located between the base and the guide rod supporting member for causing the guide rod supporting member to be displaced in a vertical direction with respect to a surface of the optical disk. A natural frequency of a system consisting of the one guide rod, the first mounting member and the chassis is set to be less than that of the optical pickup and of the optical disk.
