Abstract: A laser based inspection tool (LIT) for inspecting planar surfaces is described. In a preferred embodiment the LIT can simultaneously inspect both planar surfaces of disks for use in disk drives. In one embodiment of the invention, the incident beam is directed onto the surface to be inspected at an angle slightly offset from perpendicular so that the reflected beam is physically separated from the incident beam. The reflected beam is routed to a detector which converts the intensity of the reflected into an analog signal. The analog signal is sampled and digitized to generate pixel data stored in a buffer. Various analyses are performed on the data including calculating a rate of change in the pixel data. If the rate of change in the pixel data exceeds a selected threshold that indicates a possible defect if it occurs in the data area of the disk.

Abstract: A laser based inspection tool (LIT) for inspecting planar surfaces is described. In a preferred embodiment the LIT can simultaneously inspect both planar surfaces of disks for use in disk drives. In an embodiment of the invention, light reflected from the surface at an angle slightly offset from perpendicular is routed through a telecentric lens to a detector which converts the intensity of the reflected beam into an analog signal. The analog signal is sampled and digitized to generate pixel data. A data acquisition system sequentially stores the pixel data in a buffer. A median filter and derivative analysis can be applied to the pixel data to detect deviations indicating defects. An optional calibration system periodically reflects the scanning beam back to a detector to form a reference signal for use in absolute reflectivity measurements.

Abstract: A servo writer generates a linear servo track timing based servo pattern comprised of transitions that extend laterally of the track. At least three spaced apart write elements, two of parallel azimuthal orientation, and at least one of a different azimuthal orientation, write patterns corresponding to the write elements, fixing both the distance between transitions having different azimuthal orientation, the “A” distance, and the distance between transitions having parallel azimuthal orientation, the “B” distance. The fixed distances provide precise sensing of lateral position based on a measure of time over the “A” distance compared to time over the “B” distance.

Abstract: A disk drive having an arm assembly equipped with a primary actuator such as a VCM and a mode-canceling actuator such as a PZT mounted at a location selected in such a way that the strain in the mode-canceling actuator is in phase with sway deformations of the primary actuator produced by the vibrational modes of the arm assembly. The primary actuator is driven to exert a primary force, f ⋁ pm , on the arm assembly while the secondary driver ensures that the mode-canceling actuator applies a mode-canceling force, f ⋁ m ⁢   ⁢ c , on arm assembly such that the gain and phase of one or more vibrational modes are canceled.

Abstract: A shock mount structure facilitates shock absorption for a device. An outrigger, preferably two wing-like outriggers at diametrically opposite sides of the device, is mounted to the device at an attachment point, and is positioned between two contacting force absorbing members, distributing the shock force to the force absorption members, and supporting the device against slippage with respect to the force absorption members. Leaf spring tabs are formed within the cartridge shell, spaced from an edge of the cartridge shell to allow their flexure. The force absorption members are positioned between the device and the leaf spring tabs, contacting the tabs, such that the tabs assist in absorbing shock force directed at the leaf spring tabs.

Abstract: A shock mount structure facilitates shock absorption for a device. An outrigger, preferably two wing-like outriggers at diametrically opposite sides of the device, is mounted to the device at an attachment point, and is positioned between two contacting force absorbing members, distributing the shock force to the force absorption members, and supporting the device against slippage with respect to the force absorption members. Leaf spring tabs are formed within the cartridge shell, spaced from an edge of the cartridge shell to allow their flexure. The force absorption members are positioned between the device and the leaf spring tabs, contacting the tabs, such that the tabs assist in absorbing shock force directed at the leaf spring tabs.

Abstract: A disk drive system and method for implementing the same. The disk drive system of the present invention includes a discoid medium which rotates about its rotation axis and stores data. An actuator includes a head for reading or writing data from or in the discoid medium as it bidirectionally rotates about its bidirectional-rotation axis. The disk drive system further includes a housing which has a predetermined width and houses the discoid medium and the actuator, wherein the rotation axis of the discoid medium and the bidirectional-rotation axis of the actuator are arranged at the center in the width direction of the housing, and wherein size of the discoid medium is smaller than that of a discoid medium corresponding to a form factor of the housing.

Abstract: A method of making a calibration disk for a laser based inspection tool (LIT) for inspecting planar surfaces is described. The calibration disk has a plurality of overlapping bumps forming a circular ring with a width of one bump. The circular ring of bumps forms a feature of a known width and position on a disk which can be used to adjust one or more LIT's to yield calibrated results. The ring of overlapping bumps is preferably formed by rotating a disk substrate under a stationary pulsing laser beam.

Abstract: An actuator assembly having two coils disposed between the poles of a voice coil motor (VCM) magnet for improved dynamic performance during settling and tracking operations in a disk drive. The two coils in the VCM are connected to separate current sources to allow the current flow in the two coils to have the same sense (clockwise or counterclockwise) or the opposite sense with respect to each other. When the current flows in the two coils have the opposite sense, excitation of the principal in-plane bending mode resonance of the actuator assembly is suppressed allowing the use of an increased servo bandwidth for settling and tracking operations of the disk drive. During seek operations of the disk drive, where maximum torque on the actuator is desirable, the coil currents in the two coils are chosen to have the same sense so that the forces on the actuator from the two coils are additive.

Abstract: A system and method for using a piezoelectric (PZT) element to simultaneously actuate and sense a displacement of an arm assembly; e.g., an assembly for reading and writing data in a storage medium. The simultaneous actuating and sensing function of the PZT is achieved by adding a high-frequency excitation to a control signal which actuates the PZT. The control signal and the high-frequency excitation cause deformation of the PZT translating into arm displacement and cause the generation of an electrical response signal by the PZT. A bridge which simulates the reactance/resistance of the PZT receives the response signal and derives from it the displacement of the arm assembly. Suitable compensation techniques for active control of the PZT and for mitigation of mechanical vibrations and other disturbances experienced by the arm assembly may then be implemented based on the displacement.

Abstract: A laser based inspection tool (LIT) for inspecting planar surfaces is described. In a preferred embodiment the LIT can simultaneously inspect both planar surfaces of disks for use in disk drives. In an embodiment of the invention, the incident beam is directed onto the surface to be inspected at an angle slightly offset from perpendicular so that the reflected beam is physically separated from the incident beam. Although slightly offset the reflected beam is routed back through the telecentric lens and scanner which are used for the incident beam. Preferably an aperture mask is placed in the path of the reflected beam and the incident beam to limit the cone of scattered light. Since the incident and reflected beams are physically separated, there may be an aperture for each beam, but the two masks may be physically connected. The aperture masks may also be used for alignment adjustments of the beams.

Abstract: A dual mode actuator has an arm assembly mounted on a pivot. The arm assembly has a first arm with a first proximal flex region next to the pivot and a distal flex region at the other end of the arm and a second arm with a second proximal flex region next to the pivot and a second distal flex region at the other end of the second arm. The two arms are joined at their distal ends by a terminal piece equipped with a controlled element, such as an optical or magnetic read-write head or a sensor. A control mechanism which can include VCM coils, MEMs, piezoelectric elements or the like is provided to drive the arm assembly and cause it to execute two motions: rotation about the pivot and flexing at the proximal and distal flex regions which causes the terminal piece to rotate. thus adjusting the position of the controlled element. The rotation about the pivot and rotation of the terminal piece adjust the position of the controlled element.

Abstract: An active control mechanism and method for stabilizing a servo-controlled actuator system such as an actuator system in a data recording disk drive by compensating the vibrational modes of the actuator's arm assembly. The control mechanism has a sensing arrangement which can include one or more individual sensors attached to the actuator at locations where they generate signals in phase with the vibrational modes, and especially with all the major vibrational modes, of the arm assembly. A control mechanism derives from the signals an adjustment signal consisting of three corrective terms--a stiffening correction, an active damping correction and an inertia reduction correction--and the adjustment signal is used in the feedback control loop to stabilize the actuator system.

Abstract: A laser-based inspection tool (LIT) for disks that allows simultaneous inspection of disk surfaces for defects and curvature. The laser beam is directed by a rotating scanner, such as a rotating polygon mirror, to the input of a telecentric lens assembly that provides an output beam parallel to its optical axis as the beam is being scanned. The output beam from the telecentric lens strikes the disk surface substantially perpendicularly. The beam is then reflected from the disk surface and passes back through a collection lens to the sensing surface of an optical detector. The detector outputs analog signals that represent the X and Y positions on the sensing surface where the reflected light beam is incident, which thus correspond to the slope of the disk surface at the point where the laser beam was incident. A mechanical disk lifter moves the disk in a plane parallel to the disk surface so that different scan lines can be generated on the disk surface.

Abstract: A laser based inspection tool (LIT) for inspecting planar surfaces is described. In a preferred embodiment the LIT can simultaneously inspect both planar surfaces of disks for use in disk drives. In one embodiment of the invention, a disk is moved into an inspection subcompartment between a pair of air knives which blow partially ionized air onto the planar sides of the disk to remove loose particles adhering thereto. After the disk moves through the air knife streams, the two laser beams scan the two sides of the disk. Preferably the scan occurs after the air knives have been turned off and as the disk moves out of the inspection subcompartment. The subcompartment may optionally have an air source which forces air to flow out of the subcompartment to aid in maintaining a clean environment for inspection.

Abstract: A glass disk substrate inspection tool uses a polarized laser beam that is directed to the first surface of the disk substrate at Brewster's angle and is then transmitted through the disk substrate to a light detector that generates a signal representative of the intensity of the light received. Because the light polarized parallel to the plane of incidence, i.e., the plane formed by the line of the incident beam and a line perpendicular to the surface of the disk substrate, is completely transmitted, there is no surface reflection at either the first or second surfaces of the disk substrate. The polarized beam is directed by a first rotating scanner to the input of a telecentric lens assembly that provides an output beam parallel to its optical axis as the beam is being scanned. The beam is then directed by a first fixed mirror to strike the first surface of the disk substrate at Brewster's angle as the beam is scanned along a line across the first disk surface.

Abstract: An active mount plate having a secondary electromagnetic (voice coil motor, VCM) actuator controls the fine positioning of a magnetic read/write head relative to a magnetic disk. The active mount plate is a laminate structure comprising spring layer(s) and magnet-carrier layer(s). A spring connects a fixed part controlled by a primary VCM to a movable part for mounting top and bottom suspensions and slider/head assemblies. In one embodiment, a coil mounted on a steel coil carrier is sandwiched between permanent magnets mounted on polycarbonate spring supports. The permanent magnets are fixed, while the coil is attached to the movable part. In another embodiment, a movable permanent magnet mounted on a spring is sandwiched between top and bottom fixed coils. The centers of mass of the suspension/slider/head assemblies coincide with the attachment points of the suspensions, such that the primary and secondary actuators act independently.

Abstract: A laser based inspection tool (LIT) for inspecting planar surfaces is described. In a preferred embodiment the LIT can simultaneously inspect both planar surfaces of disks for use in disk drives. The choice of a polygon scanner is preferred, but other scanning means such as a galvonometer mirror could be used. A separate polygon scanner is used for each side of the disk. The polygons are arranged in a common plane, but rotate in opposite directions to reduce the inteference which might otherwise result when the beams pass through the central hole in the disk and impinge on the detection channel for the other side. Preferably the rotation of the polygons is synchonized and angularly offset so that the two beams are synchonized and offset.

Abstract: A laser based inspection tool (LIT) for inspecting planar surfaces is described. In a preferred embodiment the LIT can simultaneously inspect both planar surfaces of disks for use in disk drives. The LIT uses a mechanical lifter which moves the disk through the laser scan lines (i.e. perpendicular to the scan lines) to allow the entire surface on each side of the disk to be scanned. The light reflected from the surface is routed to a detector which converts the intensity of the reflected beam into an analog signal. The analog signal is sampled and digitized to generate pixel data. A data acquisition system sequentially stores the pixel data in a buffer. The edges of the planar surface in the pixel data are determined for each scan line while data acquisition is in progress. A mask is applied to direct the defect detection only to meaningful areas of the disk while data acquisition is in progress. A median filter and derivative analysis can be applied to the pixel data to detect deviations indicating defects.

Abstract: A laser based inspection tool is described which is particularly useful for inspecting one or both planar surfaces of disks for use in disk drives. The tool uses low angle reflected light and large angle scattered (LAS) light from the surface which are separately detected and pixelated to create a reflected light image and a scattered light image. The tool uses a mechanical lifter which moves the disk through the laser scan lines to allow the surface on one or both sides of the disk to be scanned. The line scanning is performed using a rotating polygon mirror (scanner) which also captures the beam reflected from the disk surface. A telecentric lens assembly (TLA) acts to ensure that the laser beam is incident at a substantially constant, nearly perpendicular angle as the beam scans across the disk and to direct the reflected and scattered light back onto the scanner. The LAS light is captured by a pair of plano mirrors disposed above and below the scan line.