Abstract: A device and method for capacitive measurement and control of the fly height of a recording slider. A recording slider is vertically spaced from a rotating disk surface by an "air bearing". The disk has a first electrically conductive pattern at its surface. The first pattern has an edge with a length extending, for example, radially. The recording slider has one or more electrically conductive rails extending transverse to the radial pattern on the rotating disk. As the disk rotates, the edge of the pattern on the disk scans across the rail of the slider. By measuring the electrical capacitance between the slider and the pattern on the disk, and by processing the electrical capacitance measurement signal, a vertical spacing signal proportional to the vertical spacing between the disk and the slider can be obtained.

Abstract: A magnetic recording disk is formed on a rigid aluminum substrate coated with a polymeric dielectric layer. A thin film metallic position-indicating track is applied to the upper surface of the dielectric layer. The dielectric material is coated with a magnetic recording medium. A thin film of aluminum forms the patterned capacitive and optically reflective track. The dielectric layer is composed of a very similar material to the matrix material in the magnetic recording medium.The disk can be flexible or floppy and it is not necessary to have the extra dielectric layer in such a case, where the substrate is a dielectric.

Abstract: A linear disk actuator is disclosed incorporating a magnetic circuit for reducing stray magnetic fields in the region of the disks and recording heads of a magnetic recording disk system. The moving part of the actuator is provided with a plurality of coils mounted thereon, at least two of which are energized simultaneously and in magnetically opposing relationship to reduce the amplitude of the stray magnetic fields. Movement of the actuator is achieved by both energized coils interacting with a set of alternating poles positioned on the stationary part of the actuator.

Abstract: An oscillating pneumatodynamic bearing takes the form of a laminated transducer disk cooperating with a flat surface or a tubular transducer cooperating with a rod or an enclosing tube. Such bearings are also known as squeeze bearings. At least one piezoelectric, magnetostrictive or electrostrictive material is laminated with another material to provide oscillation of the transducer portion of the bearing so that the transducer portion is able to fly above a bearing surface on a fluid which is usually ambient air compressed by the mechanical oscillation of the transducer portion at an ultrasonic frequency. The disk or the tube is connected mechanically to supports and to its electrical sources of energy or signals at points along the loci of zero oscillation or minimal oscillation. With a laminated disk, a nodal circle is the locus of zero oscillation.

Abstract: A capacitive variation sensor includes one or more elements providing inductive reactance in the form of thin film coils. This enables a capacitive variation sensor to be integrated on a substrate along with a thin film magnetic read/write head. One element of the capacitive variation sensor is a sensing electrode, and in some embodiments of the invention a dedicated sense electrode can be eliminated by employing the pole tips of the thin film magnetic read/write head as the sense electrode.

Abstract: An improved squeeze bearing apparatus exhibits torsional stiffness or rotational restraint since its rod-like bearing member (22) and its sleeve-like bearing member (28) comprise non-circular perimeters (26,32).

Abstract: Tubular, pneumatic, vibratory transducer bearings incorporate a pair of colinear nested tubes with differing radii joined together at their inner and outer radii respectively. The mode of oscillation of the structure is designed to produce minimal vibration of the load carried on points of low vibration on the surface of the inner tube. The inner tube is far longer than the outer tube which is piezoelectrically excited at the correct frequency to produce the mode of oscillation desired for low vibration, automatically or self-pressurized bearing arrangement. The tubes are cylindrical and the inner tube rides on a cylindrical rod. The mounting points are at saddle points on the surface of the inner tube. The shortness of the outer tube of the transducer reduces the weight of the transducer.

Abstract: A writing implement having special applicability for use as a pressure and acceleration sensitive element for use in a Signature Verification System. The pen structure includes both a writing implement for making a visible record and also includes unique transducer structures for providing both acceleration and pressure data to a remotely located verification system. The pressure sensing element is axially mounted within the pen and produces pressure signals due to axial pressure on the pen tip as an individual writes. The accelerometer structure comprises a hollow tubular piezoelectric member supported at one end and having four circumferentially disposed electrodes on the outer surface thereof, which are appropriately interconnected to produce two orthogonal acceleration component signals A.sub.x and A.sub.y.

Abstract: A linear motor adapted for driving a magnetic recording head reciprocably across the surface of a magnetic recording disk in a disk file has its stator located between the disks. The stator includes parallel magnetic yokes composed of plates extending parallel to the disks. At least one of the plates carries an array of regularly spaced and alternating magnetic pole elements, rigidly secured to one yoke with a gap extending between the yokes including the alternating poles providing a space within which the armature reciprocates, from one magnetic polarity to the opposite a plurality of times per reciprocation of the armature. End poles are provided at each end of the array, which are matched to collect the return flux from the adjacent distal pole to reduce fringing flux which emanates towards the disks and the recording heads.

Abstract: A method and device for detecting Neel wall segments in a cross-tie memory system involves applying a magnetic field to the Neel wall segments of a given polarity so that these Neel wall segments expand into a transverse domain. The transverse domain is then sensed with a magnetoresistive detector.

Abstract: Polymeric sulfur nitride is a conductive metallic compound providing a highly electronegative contact for both n- and p- type semiconductor materials. Tests show the electronegativity to be higher than Au. Larger barriers are obtained for n-type semiconductors and smaller barriers, or Ohmics, for p-types.

Abstract: A high speed, small diameter disk storage system having a plurality of disk drive devices utilizing disks with a nominal 65 mm diameter rotated at a speed of approximately 10,000 RPM which can be optimally arranged in a four drive system to match the space geometry of the traditional half-high flexible disk drive used in a personal computer.