Abstract: An electrostatic discharge device for a flying height tester which measures the air gap of a recording head. The tester includes a transparent disk that is rotated by a spindle motor. The spindle motor is mounted to a spin stand. The tester has a manifold that is mounted to the spin stand and directs a flow of ionized fluid to a bottom surface of the disk. The manifold is also electrically grounded. The ionized fluid and electrically grounded manifold provide an electrical path that discharge electrostatic charge located on the bottom surface of the disk. The manifold extends from an inner disk diameter to an outer disk diameter so that ionized fluid is introduced to the entire bottom surface of the rotating disk. Additionally, the manifold location is such that the ionized fluid provides an electrical path from the disk to the manifold that is relatively constant across the surface of the disk.

Abstract: A rugged spindle for a disk certifier that test the disks of a hard disk drive. The spindle contains a first bearing and a second bearing that are coupled together by a shaft. The first bearing is coupled to a chuck that captures a disk. The second bearing is coupled to the spindle shaft of an electric motor which rotates the disk. The bearings each contain an outer graphite sheath that is separated from a hardened housing by an air bearing. The connecting shaft is bonded to the first and second bearings by an adhesive that is injected through longitudinal passages of the shaft. The bonding adhesive flows along the interface of the connecting shaft and bearings until the adhesive fills an indicator slot of the shaft. Air bearings are created during the bonding process of the second bearing to insure an accurate relationship between the two bearings and the housing.

Abstract: A flying height tester that can vary an air pressure and measure an air bearing height between a slider and a substrate. The substrate is located within a chamber that has an air pressure. The tester includes a loader which places a slider adjacent to the substrate. An optical system computes the air bearing height from a light beam that is directed through the substrate and reflected off of the slider. The chamber is coupled to a pressure control system that can vary the pressure of the air surrounding the slider. The pressure control system varies the pressure to simulate slider operation at various altitudes. The tester of the present invention can thus measure air bearing height while simulating various altitude conditions.

Abstract: A hard disk drive flying height tester loader which moves a head gimbal assembly (HGA) about the pivot axis of the HGA. The HGA is mounted to a clamp that is attached to a pivot arm. The pivot arm is attached to a cam follower which follows a cam. The cam is moved by a motor that is attached to a stationary sideplate. Movement of the cam rotates the pivot arm, clamp and HGA between a first position and a second position. The pivot arm is Coupled to the stationary sideplate by a ball bearing assembly which has a radius of curvature. The center of the ball bearing radius intersects the pivot axis of the HGA so that the clamp and HGA rotate about the pivot axis when the motor and cam move the pivot arm between the first and second positions.

Abstract: A preferred embodiment of the present invention comprises two laser sources of different frequency monochromatic light that are time-multiplexed through a beam combiner to produce composite beams that are steered to a gap between a slider and a disk. A reflected light that includes an interference pattern is then directed to an aperture plate that permits a spot of light to be directly detected by a photodiode which reads the intensity. Measurements of the intensity are taken at respective time-points to sample each laser source, and the measured intensities are compared to determine the slider to disk spacing. Since different frequency light will have different intensity for the same spacing, integer ambiguities can be directly resolved.

Abstract: A slider is mounted to a rotary drive mechanism. The slider is loaded, i.e., moved toward and positioned near a disk surface, by rotary movement of the rotary drive mechanism in a first rotary direction. Similarly, the slider is unloaded, i.e., moved away from the disk surface, by rotary movement of the rotary drive mechanism in a second rotary direction which is the reverse direction of the first rotary direction.

Abstract: A preprogrammed controller, preferably a stored program computer such as an IBM PC computer, is programmed to automatically control all the steps in the testing of a MR reproduce head. First, the magnitude of the sense current is established by command of the controller, and a voltage proportional to the sense current flowing in the head is monitored by the controller. An electromagnet, having high permeability pole pieces, and whose current is programmed by the controller provides a the magnetic field for exciting the MR head. The MR device is placed on an measured magnetic equipotential of the field of the electromagnet, and a Hall sensor magnetic detector is placed on the same magnetic equipotential line but in a different physical position from the MR device. The output of the Hall sensor is fed into the preamplifier electronics, digitized by a converter and this digital output is stored in the controller memory for future processing.

Abstract: An automatic surface inspection apparatus comprises a light source that provides a coherent light beam that is spit and then recombined in a prism to generate an interference pattern. A cylindrical lens projects the interference pattern onto the surface of a disk as a line of light. A linear detection array converts the reflected line of light into an electrical signal that has a magnitude which varies dependent upon the reflected light intensity. Defects present on the surface of the disk cause variations in the reflected light intensity manifested as differences in the electrical signal output by the detection array.

Abstract: A burnish head comprising a slider body having a single crystal diamond attached to a rear portion flies above the disk surface at a relatively low flying height when the disk is rotated at a high angular velocity. The diamond produces acoustic waves that cut or crack disk asperities, resulting in a highly-smooth disk surface suitable for near-contact or in-contact magnetic recording.

Abstract: A pneumatically operated vacuum chuck for releasably securing data discs includes an arbor with an annular land disposed at the distal end thereof to engage the inner periphery of the disc. An annular groove is formed concentrically in the land to exert a suction grip on a data disc. A piston assembly is secured in a bore within the arbor, the distal end of the piston assembly including a resilient bushing that expands diametrically upon proximal retraction to block the egress path of the disc from the annular land. The piston head engages the bore with a sliding seal, and the sealed interior chamber of the arbor communicates with the annular groove at the distal end of the arbor. A compression spring biases the piston assembly proximally, and air pressure applied to the proximal end of the piston assembly drives the piston assembly distally against the spring.

Abstract: An apparatus and method for measuring the space between a transparent member such as a disk, and reflective member such as a slider, by detecting a change of polarization of a reflected light beam. The apparatus includes a light source that emits a light beam. The light beam is circularly polarized and directed onto the disk and reflected off of the interface between the disk and the slider. The reflected light beam is split into four separately polarized beams by a beam splitter/polarizer assembly. The four light beams have varying intensities that are measured by photodetectors. Stokes parameters are computed from electrical signals that are generated by the photodetectors. The Stokes parameters correlate to the change in polarization of the reflected light beam. Ellipsometric parameters delta and psi are computed from the Stokes parameters.

Abstract: A preprogrammed controller, preferably a stored program computer such as an IBM PC computer, is programmed to automatically control all the steps in the testing of a MR reproduce head. First, the magnitude of the sense current is established by command of the controller, and a voltage proportional to the sense current flowing in the head is monitored by the controller. An electromagnet, having high permeability pole pieces, and whose current is programmed by the controller provides a the magnetic field for exciting the MR head. The MR device is placed on an measured magnetic equipotential of the field of the electromagnet, and a Hall sensor magnetic detector is placed on the same magnetic equipotential line but in a different physical position from the MR device. The output of the Hall sensor is fed into the preamplifier electronics, digitized by a converter and this digital output is stored in the controller memory for future processing.

Abstract: Light is focused on an interface between a transparent probe and a surface to be analyzed. The probe is lowered onto the surface using a computer-controlled actuator. Light reflected from the surface of the probe which is closest to the surface and the surface itself recombines, producing interference effects from the spacing between the probe and the surface over a 2-dimensional area. Since the shape of the probe in known beforehand, the profile of the surface can be readily calculated from the 2-dimensional measurement of the spacing between the probe and the surface. This surface profile indicates the roughness of the surface. The surface hardness and other surface properties can be measured by pressing the probe onto the surface. The contact load between the probe and the surface is detected by a load cell. The force with which the probe is being pressed onto the surface is measured using the load cell.

Abstract: The apparatus and method for measuring a small spacing down to contact uses an interferometric fringe intensity calibration to calibrate maximum and minimum intensity of two or more monochromatic or quasi-monochromatic interference patterns caused by a spacing between two articles, one of which is transparent. The intensity calibration is done by measuring maximum and minimum fringe intensity of each color while altering the spacing by at least 1/4 of the wavelength of the light or other electromagnetic radiation being used. The calibration by changing spacing allows the fringe order to be calculated for each wavelength of the radiation being used. This calibration procedure allows the maximum and minimum intensity of the radiation to be known, as well as the fringe order of the interference patterns to be calculated. With the maximum and minimum intensities and the fringe orders known, the spacing is readily calculated from interferometric theory.

Abstract: The apparatus and method for measuring a small spacing down to contact uses an interferometric fringe intensity calibration to calibrate maximum and minimum intensity of two or more monochromatic or quasi-monochromatic interference patterns caused by a spacing between two articles, one of which is transparent. The intensity calibration is done by measuring maximum and minimum fringe intensity of each color while altering the spacing by at least 1/4 of the wavelength of the light or other electromagnetic radiation being used. The calibration by changing spacing allows the fringe order to be calculated for each wavelength of the radiation being used. This calibration procedure allows the maximum and minimum intensity of the radiation to be known, as well as the fringe order of the interference patterns to be calculated. With the maximum and minimum intensities and the fringe orders known, the spacing is readily calculated from interferometric theory.