Abstract: The carriage optics system for an optical data storage system includes a read/write head that consists of fixed and moving optics. The moving optics includes a carriage actuator that is equipped with a beam relaying telescope lens system that minimizes the defocusing effects of the movement of the carriage actuator.

Abstract: An improved coarse access and tracking servo system for use with an optical disk storage system is disclosed. Concentric servo tracks placed on the disk are readily distinguished from data tracks placed on the disk which may or may not be present on the disk depending upon the amount of information that has been written on the disk, i.e., how "full" the disk is with respect to its maximum capacity for storing data. A predetermined signal is embedded within each of the plurality of concentric servo tracks found on the disk. A radial strip or line, sufficiently long to always include at least one servo track, but also long enough to include data tracks, if any, on either side of the illuminated servo track is projected on the surface of the disk in order to detect the servo tracks.

Abstract: An optical system for writing and reading data from a rotating optical storage disk, comprising a first, second and third coherent light source, providing coarse seek, reading, and writing functions, the three writing sources sharing a plurality of optical elements in common, all cooperating to provide for the coarse seek, fine seek, focus and tracking functions of the device. The read and the write optical beams are optically coupled together to ensure proper spacing of a newly written track with regard to the previously written track.

Abstract: A self contained, replaceable diode laser module for providing a fully collimated, de-astigmatized, and circular cross-sectioned beam. In the preferred embodiment a first compound spherical lens partially collimates the beam. An in-line combined cross-section modifier system then de-astigmatizes and modifies the cross-section of the beam. The beam modifier system is comprised of first and second triangular prisms oriented at non-normal angles to the path of the beam. This allows both the cross-section and the astigmatism of the beam to be corrected. A planar mirror between the first and second prisms directs the beam from the first prism to the second prism, so that the beam can exit the second prism co-axial with the incident beam path. The beam then enters the second collimating subsystem.

Abstract: An optical head structure, movable to scan over a disk surface, includes a fixed optical arrangement. Fine focussing and side-to-side adjustments for scanning are effected by movements of another lens mounted on a substantially stationary part of the system structure. The movable lens is generally aligned with the axis of the fixed lens on the movable head structure. In an alternative embodiment, lateral adjustments of scanning spot position are made by pivoting a reflecting mirror on the stationary structure and axial adjustments of the scanning spot are made by axially moving a lens on the fixed structure. Light paths in the movable head structure are altered by reflecting mirrors, all such mirrors being in fixed relationship with the fixed objective lens. The movable head structure bearing fixed lenses and fixed mirrors mvoes in an arc, not concentric with disk rotation, to traverse the disk and locate a desired track.

Abstract: A subaperture optical system for preventing interference between light inadvertently reflected from the protective overcoat of an optical recording disk from disruptively interfering with light reflected from the active layer of the optical recording disk, thereby causing coarse servo tracking errors as the coarse servo actuator carriage translates over the coarse servo tracks on the disk service. The optical system is comprised of a laser light source, a collimating lens system, an astigmatizing lens system, a subaperture mirror, a carriage actuator, a beam relaying telescope, an objective lens, an objective lens focus actuator, a reflected coarse servo beam focusing lens, and a coarse servo detector. The laser issues a beam which follows a first subaperture path that is parallel to, but off center from, the optical axis of an objective lens of the optical system. The beam is formed into a line focused spot which is focused on the disk surface at a non normal angle.

Abstract: A beam alignment system and method for aligning a first radiation beam with respect to a second radiation beam as these beams share a desired optical path. Beam steering means, such as a galvonometer controlled mirror, steer the alignment of the first beam as it enters the shared optical path. Detection means are employed to sense the relative alignment between the first and second beams as they travel through the shared path. This sensed alignment is compared to a desired alignment, and a position error signal is generated to indicate the error therebetween. The position error signal, in turn, is used to steer the galvonometer controlled mirror in order to force the beam alignment error between the two beams to zero.

Abstract: A beam alignment signal processing system wherein a true beam position error signal is generated regardless of beam intensity. This beam position error signal is used within a beam alignment system that maintains a desired alignment between first and second beams traveling in parallel along a desired optical path. A detector senses the position of the beams as the beams (or portions of the beams) are directed onto a surface thereof. The detector generates a set of position signals that indicate the position at which a beam, or at which an energy centroid associated with a plurality of beams, falls upon the detector surface. A first set of position signals is generated corresponding to the position of the first beam on the detector surface with the second beam turned off. These signals are stored in signal storage means. The second beam is turned back on, and a second set of position signals is generated corresponding to the position of the centroid of the first and second beams on the detector surface.

Abstract: Improved laser system gain is achieved by using Gadolinium to totally replace the Yttrium in a Lithium Yttrium Fluoride (YLF) host crystal so as to increase the amount of Neodymium which can be doped into the host crystal.