Abstract:
A system and method for controlling positioning of an optical pickup unit relative to at least one track of an optical data storage medium include an adaptive track position feedback controller that compensates for defocus of an optical beam relative to the optical data storage medium associated with movement across the medium and/or disturbances in distance between a lens of the optical pickup unit relative to the optical data storage medium. A track position feedback controller may include an adaptive term or parameter based on a focus (or defocus) error signal generated by a focus position feedback controller and associated sensors or detectors of a quadrature photodiode integrated circuit (PDIC).
Abstract:
Optical scanning device for scanning an information plane (1a) of a disc-shaped optical recording medium (1) having an outer surface (1b) extending parallel to the information plane. The scanning device comprises a radiation source (7) for supplying a scanning beam (7a), and an optical scanning unit which comprises a lens system for focusing the scanning beam to a scanning spot (7b) on the information plane. The lens system has an optical axis (9) and comprises a first lens unit (9a) with a first lens (9a1) having an entrance side (11) and an exit side (13), and a second lens unit (9b) with a second lens (9b1) situated opposite the exit side of the first lens. The scanning unit also comprises a drive means for displacing the first lens along the optical axis and an adjusting means for adjusting the second lens with respect to the recording medium. To inhibit spherical and/or comatic and/or astigmatic aberrations during scanning, the adjusting means comprises a rotatably driven rotation element (15) which forms part of the second lens unit, is journaled in a stationary element (17) and has a disc-shaped surface (15a) provided with a pattern of grooves for cooperation with the outer surface of the recording medium.
Abstract:
A flying head mechanism includes a flying head, a suspension and an actuator which applies a load force through the suspension. The load force applied by the actuator is adjustable while the head is in operation. The actuator may actively control load force as part of a feedback loop which maintains the flying head at a constant flying height. One embodiment disclosed includes a voice coil actuator. In embodiments using an optical flying head, a conventional focus sensor may provide a signal indicative of flying height, since the focus signal inherently indicates flying height error.
Abstract:
The present invention provides a linear motor for a laser beam recorder for mastering of optical media. The linear motor comprises a base and an actuator, the actuator being mounted on the base in a flexible way, such as via a leaf spring. The actuator may comprise a balance mass acting as a counter mass. The balance mass is preferably formed by an essential component of the linear motor.
Abstract:
An optical scanning device is used for scanning first and second information layers with first and second radiation beams. The device includes a radiation source and an objective lens assembly (31). The lens assembly includes a doublet-lens system (61, 62) including a first objective lens (61) with a first cross-section having a first diameter (d 1 ) and a second objective lens (62) with a second cross-section having a second, smaller diameter (d 2 ). The first and second lenses are arranged for transforming the first radiation beam to a first focused radiation beam having a first numerical aperture. The objective lens assembly further includes a third objective lens (63) for transforming the second radiation beam to a second focused radiation beam having a second, smaller numerical aperture. The second and third objective lenses are integrally formed in one body (64).
Abstract:
The invention relates to an optical pickup device for recording and reproducing information using holography while preventing the degradation of recording and reproduction accuracy due to external vibrations and changes in position relative to the recording media. An optical pickup device (11) uses a positioning device for adjusting the position of a pickup body (12) to correct the deviation of the relative position between the pickup body (12) and an optical information recording medium (1). The positioning device varies the position of the pickup body (12) in the directions perpendicular and parallel to the surface of the optical information recording medium (1) and also varies the angle of the pickup body (12) to the surface of the recording medium.
Abstract:
A motor assembly incorporated in an optical read/write head to effect tracking or focusing movement of an optical element comprises a generally horseshoe-shaped field assembly having two slotted pole pieces (52, 54, 76, 78, 86, 88) magnetized with opposite polarity by a permanent magnet (56, 80, 96) to provide two pairs of field poles confronting corresponding poles of a moveable armature (24, 26). A single coil (58) is wound through the slots of the pole pieces (52, 54, 76, 78, 86, 88) around the inner field poles (60, 62). The direction and intensity of the current flowing in the field coil (58) determines the degree to which the permanent magnetism is reinforced in one pole of each pole piece and counteracted in the other pole of each pole piece, thereby causing corresponding movement of the armature (24, 26).
Abstract:
The present invention is related to a method and apparatus for limiting movement of an actuator assembly (134) in a data storage/retrieval system (100). In one embodiment of the apparatus, a base (104) is provided on which first (154) and second (220) devices are mounted. The first device (154) is rotatably mounted to the base (104) and reads or writes data to a data storage disk (126). The second device (220) operates between first and second states. In the first state, the first device (154) is capable of movement with respect to the base (104). In the second state, the second device (220) operates to inhibit movement of the first device (154) with respect to the base (104). The second device (220) may operate in the first state when the first device (154) is reading or writing data to the data storage disk (126), and the second device (220) may operate in the second state when the first device (154) is not reading or writing data to the data storage disk (126). In one embodiment, second device (220) is rotatably mounted to the base (104) between first and second positions. The second device (220) operates in the first state when the second device (220) is in the first position, and the second device (220) operates in the second state when the second device (220) is in the second position. The second device (220) engages the first device (154) to inhibit movement thereof when the second device (220) is in the second position.