Abstract: A method of forming a discrete track recording pattern in a magnetic recording disk. In one embodiment, the discrete track recording pattern may be formed in a NiP layer continuous throughout the discrete track recording pattern. Alternatively, the discrete track recording pattern may be formed in a substrate.

Abstract: A method of forming a discrete track recording pattern in a magnetic recording disk. In one embodiment, the discrete track recording pattern may be formed in a NiP layer continuous throughout the discrete track recording pattern. Alternatively, the discrete track recording pattern may be formed in a substrate.

Abstract: A method of forming a discrete track recording pattern on a soft magnetic underlayer of a perpendicular magnetic recording disk. In one embodiment, the soft magnetic underlayer is continuous throughout the discrete track recording pattern.

Abstract: Apparatus for detecting defects in a substrate comprises a laser for providing a laser beam, and a bi-cell photodiode comprising two cells. Circuitry coupled to the bi-cell photodiode provides a signal equal to (L−R)/(L+R), where L and R equal the signal strengths of the signals provided by the left and right photodiode cells, respectively. The photodiode is biased so that it exhibits reduced capacitance, and can provide increased output signal bandwidth.

Abstract: Substrate inspection apparatus in accordance with the invention comprises optics for reflecting a laser beam off of a substrate and a detector for detecting the reflected laser beam. If a defect is present at the point where the laser reflects off the substrate, the laser will be deflected at an angle. Circuitry coupled to the detector generates a first signal that provides a measure of the extent to which the laser beam is deflected. (This signal is a measure of the slope of the defect walls.) An integrator receives that signal, and generates a second signal that is the integral of the first signal. The second signal is a measure of the height of the defect. The first and second signals provide a measure of the types of defects present on the substrate, and are used to determine whether the substrate is acceptable or should be rejected. In accordance with a second embodiment of the invention, laser beams are reflected off both the top and bottom surfaces of the substrate and detected by detectors.

Abstract: A method in accordance with our invention for providing texture bumps on a substrate comprises the step of forming elliptical ridge-shaped bumps on the substrate. In one embodiment, substrate is used in the manufacture of a magnetic disk used in a disk drive. The elliptical bumps cause less vibration of the read-write head than circular bumps. The elliptical bumps also provide reduced friction between the disk and a read-write head during use.

Abstract: A method for texturing a substrate and the resulting substrate. A substrate made of glass ceramic is textured using laser radiation to form a texture feature. The laser radiation may be applied with a degree of overlap. Additionally, the texture feature may be elongated or continuous in the circumferential direction. The radiation is applied such that the texture feature has smaller texture features formed thereon.

Abstract: A calibration disk for calibrating the fly height of a head, includes spaced circumferencial bands on the disk extending in a concentric fashion from adjacent an outer diameter of the disk to near an inner diameter of the disk. Each of the bands include radial and circumferencial spaced asperity emulating bumps having a population sufficient to produce a constant and continuous output signal from a glide head when the glide head flies lower than a maximum height of the bumps. The height of the bumps within individual bands are substantially uniform, and the average heights of the bumps in each band differ from each other. The configuration of the bumps on the calibration disk advantageously avoids errors caused by disk waviness, runout, and contamination. Further, using the differing heights of the bumps on the calibration disk, a glide head can be calibrated on the glide tester without using an independent fly height measurements for the glide head.

Abstract: A method for manufacturing a magnetic disk comprises the steps of depositing NiP (20) on a substrate (22); depositing NiNb (24) on the NiP; and laser texturing the NiNb. "Sombrero" shaped texture features are more easily formed on the substrate/NiP/NiNb structure than a substrate/NiP structure. The disk is completed by depositing an underlayer (e.g. sputtered Cr or NiP), a magnetic layer (e.g. a Co alloy) and a protective overcoat (e.g. by hydrogenated carbon).

Abstract: A method for texturing a glass ceramic substrate comprising the steps of applying a laser pulse to the substrate such that a portion of said substrate is heated to a temperature higher than the glass transition temperature of the glass phase of said substrate but lower than the melting point of the crystal phase of said substrate.

Abstract: Formation of laser texture features simultaneously on the target surfaces of each side of magnetic recording disk is facilitated by optical and mechanical components permitting excellent balance of optical power between each target surface, excellent matching of the radial position of laser texture features between each target surface, and excellent focusing of laser beams on each target surface. Polarization of the source laser beam may be used to controllably balance and direct a single source beam into individual beam paths for each target surface. Handling, automation complexity, and manufacturing time is thereby reduced.

Abstract: Reflection of a generated radiation beam (e.g., laser) from a disk substrate during radiation-induced texturing such that the reflection interferes with the generated radiation beam is eliminated as follows: the beam path of the laser beam is passed through focusing optics to focus the beam to a spot on the substrate surface; the beam path is offset from the center of the focusing optics so that the focusing optics bend the beam path, and further so that the beam is angled from normal to the surface of the disk, for example by between 2 and 5 degrees; and that portion of the beam reflected by the disk surface is blocked by appropriate means prior to its impinging upon the source of the generated radiation beam.

Abstract: An optimal structure for a quadrilayer magneto-optic data storage medium is described. The structure has superior characteristics of signal to noise, reflectivity, ellipticity, write sensitivity, and stability.

Abstract: In the present invention a magnetic data storage includes disk recesses formed in the magnetic layer. The recesses are located in pairs on opposite sides of the data tracks, and the disk is initialized by applying a magnetic field perpendicular and parallel to the surface of the disk, thereby forming positive magnetic poles at respective edges of the recesses. The read/write head generates a signal as it passes over the pairs of recesses, and this signal is used to adjust the position of the head with respect to the data track. The recesses may advantageously be arranged in a stair step pattern which results in a signal having the same sequential characteristics for adjacent data tracks. The spacing between the recesses may be used to represent ROM data or header information, such as track addresses or synchronization marks.