Abstract: An apparatus and method for filtering intersymbol interference from an information signal generated from a storage medium. This apparatus utilizes a delay line, gain devices, summing devices, and has specified transfer functions. Furthermore, this apparatus and method can make real time adjustments in order to maintain an optimal level of filtering.

Abstract: In an information disk drive system, a pivoted shutter opening lever is positioned in a cartridge receiving guide in the same plane as the disk in the cartridge. The lever is mounted on a movable pivot with a shutter engaging member positioned to begin opening the cartridge shutter to expose a segment of disk recording tracks only after the segment is inside the disk drive and to complete opening of the shutter at an intermediate stage of cartridge insertion to allow nesting of disk access components within the disk access opening in the cartridge prior to the cartridge reaching its final operating position. Interference between the opening lever and the fully opened shutter during final travel of the cartridge is avoided by a mechanism which moves the lever pivot by a sufficient amount to allow the shutter engaging member to translate in a straight line parallel to the insertion path of the cartridge during final insertion motion of the cartridge. Two embodiments of the pivot moving mechanism are shown.

Abstract: A disk drive spindle and spindle motor assembly is mounted on a support platform which is translated reciprocally toward and away from a stationary disk cartridge by a pair of rotationally driven cranks positioned along opposite sides of the platform. The cranks are coupled to the platform by eccentrically mounted support rods loosely captured in the span between dual sets of parallel, compliant leaf springs attached to side edges of the platform. The rotational cranks are provided with a degree of overtravel to forcefully urge the platform, when in the operational position, against precision stops formed on the underside of a mount plate located between the platform and disk cartridge. The spatial relationship of a disk engaging surface on the drive spindle relative to the precision stops is such as to precisely position the rotating disk in parallel with the tracking axis of the read/write head of the system.

Abstract: A method and apparatus for increasing the information storage capacity of optical recording structures by utilizing a laser beam of different powers to produce a selected one of a plurality of different physical states. These states each produce a different optical contrast. If the number of different optical contrasts is greater than two, then encoding schemes based on three or more bits may be used to store the information thus increasing the data density on the optical recording structure, such as an optical disc. In order to promote the stability of the physical states and to enhance the speed of transition between the states, a stabiliment layer is added adjacent and covering the photosensitive layer of the disc. The stabiliment layer itself is ablated in the ablation state of the photosensitive layer.

Abstract: In an optical or magneto-optical disk drive system adapted to receive a shuttered disk cartridge, interference between the disk clamp and the shutter during cartridge insertion is obviated by securing the clamp onto a sliding mount plate which is normally biased to hold the clamp in a rearward position displaced from its normal operating position in alignment with the disk spindle-drive. A drive cam engaged by the leading edge of the cartridge during insertion is drivingly coupled to the mount plate by a double rack and pinion arrangement to drive the mount plate forward into normal operating position after the cartridge shutter is opened. To assure that the clamp is firmly positioned in alignment with the disk spindle-drive, the pinion is compliantly mounted to allow slight overtravel of the drive cam after the clamp mount is arrested by the precision stop thus exerting a forward bias force to the amount plate which holds the clamp mount firmly in place.

Abstract: At the conclusion of a track seek operation, handoff to track following servo control is delayed for a short time period during which the drive microprocessor determines if the head has failed to stop at the target track by sensing the occurrence of a predetermined number of track crossing pulses, the detection of which causes iterative generation and application of braking current pulses to the head actuator motor. The amplitude and duration of each braking current pulse is chosen to cause forward motion of the head to be retarded to a predetermined percent of its pre-existing velocity. The microprocessor routine includes provision for iteratively determining when the head has slowed to a velocity which allows the track following servo to acquire control of the head. Once stopped on a track, a short seek is executed to return the head to the desired target track.

Abstract: A linear drive apparatus for the load mechanism of an information storage disk drive system utilizes over-center pivotable link pin connections between a linear drive lever and counter-rotating drive cranks used for raising and lowering a disk spindle drive into and out of engagement with the storage disk. The over-center pivoting link pins provide an idle period for the spindle lift mechanism while the same linear drive lever powers the cartridge positioning apparatus utilized for loading and unloading the disk cartridge under power from the disk drive system.

Abstract: A random access information storage disk drive system of the optical or magneto-optical type with the read/write head mounted between parallel flexures for suspension in a linear actuator motor. Dynamic spring force compensation is provided incrementally as the head is moved radially inward and outward of the at-rest position of the flexures to compensation for the increasing restoring force exerted by the flexures as the head is moved towards the extremes of its tracking path.

Abstract: Cartridge positioning apparatus for loading and unloading the disk cartridge of an information storage disk drive system employs a dual function, motor-actuated, laterally moving linear drive mechanism to drive a plurality of drive plates located in an interstitial space between a cartridge receiving guide means and a central mount plate by means of a drive tab extending up through the mount plate. The tab engages a camming plate which operates against the central portion of a pivoted sector gear to convert the lateral tab drive motion into amplified longitudinal motion parallel with the direction that the disk cartridge is inserted and removed. The camming plate includes an idling provision to hold the sector gear stationary while the motor-performs other load functions. The sector gear drives a longitudinal drive mechanism which carries one or more members adapted to contact the disk cartridge for loading or unloading the cartridge depending on the direction of movement of the motor-actuated drive tab.

Abstract: Single stage tracking actuator apparatus for an optical or magneto-optical disk drive system in which a read/write head is suspended by parallel flexures between mutually isolated magnetic circuits disposed on opposite sides of the head, one of the magnetic circuits being nested in the span between the parallel flexures. The flexure suspension provides friction-free translatable motion of the head in the longitudinal direction parallel to a radial line relative to the information storage disk. An electromagnetic coil provided with tracking actuator signals is formed about the head axially concentric with and transverse to the longitudinal center line of the head and is centrally positioned on the head between the points at which the free ends of the flexures are attached to the ends of the head. The end turn segments of the coil are disposed transversely of magnetic flux lines in elongated air gaps formed in the magnetic circuits to provide the driving force for the actuator.

Abstract: Apparatus for centering and clamping a disk on a spindle-drive is disclosed. A bistable magnetic clamp normally held in an axially offset position from the plane of the disk is preferentially drawn to a coupler washer on the spindle-drive when the spindle-drive and clamping device are relatively moved toward each other after the disk is inserted into the drive. To accommodate significant initial misalignment of the disk, as might typically occur with a cartridge mounted disk, in a very short throw clamping motion, a multi-frustrum centering member is used. The frustrum surface nearest the disk has a gradual slope assuring meshing of the centering member with the central aperture of the disk over a wide range of initial misalignment. Once the disk is coarsely centered, precision centering is achieved during the final clamping stage by the second frustrum surface which is at steep slope relative to the plane of the disk.

Abstract: During the arrival phase of long seeks, e.g. the last six tracks of a seek, and during the entirety of relatively short seeks, e.g. seeks of less than 256 tracks, position mode servo control is employed by locking an actual tracking error feedback signal to a microprocessor-synthesized reference tracking error signal. The position mode servo feedback loop employs a parallel combination of a synchronous demodulator and a phase-frequency detector to achieve good locking performance over the entire frequency spectrum of the synthesized reference tracking error signal.