Abstract: A hydrodynamic tape guide includes a thin metal foil attached to a substrate by a pin inserted into a groove in the substrate. The groove is of a geometry including a first region of a relatively small width and at a relatively shallow depth and a second region of a relatively large width deeper into the substrate. The pin is of a thickness greater than the first width, but less than the second width.

Abstract: An optical disk drive is disclosed in which sensing the position of a tilting prism driven by a fine tracking actuator uses the optical beam prior to its interaction with an optical disk. The optical beam emitted by a laser is redirected by the tilting prism. Most of the optical beam is reflected by the tilting prism in a direction through an objective lens for focused interaction with an optical disk. assuming a disk is mounted in the optical disk drive. The remainder of the optical beam is transmitted through the tilting prism, including any offset of the beam resulting from the refraction characteristics of the tilting prism, and received by a split far field detector. The split far field detector measures the offset of the optical beam which is a direct measure of the rotational position of the tilting prism. A relative position error signal is then generated and input to the coarse tracking actuator to coordinate its operation with that of the fine tracking actuator.