International Business Machines Corporation

Stormedia, Inc.

Gerard H Vurens

Christopher S Gudeman

John S Foster

Li-Ju J Lin

Steven W Meeks

Andrew Ching Tam

Peter Michael Baumgart

Thao Anh Nguyen

Atef H Eltoukhy

Yassin Mehmandoust

Douglas J Krajnovich

Fior D Sargent

Hamid R Samani

A method and apparatus for inspecting a reflective surface, or material on such surface, such as lubricant and planarizing layers on a magnetic media storage disk. A beam of controlled polarization impinges obliquely at a spot in the plane of the disk. A collector such as an integrating sphere is spaced away from the disk and has an opening oriented to catch the oblique specular reflectance from the surface. Preferably the opening is substantially larger than the beam, so that disk run out does not send the beam astray or defeat its measurement, and the oblique beam is aimed at an angle lying between the Brewster angle of the lubricant and that of the adjacent layer. A temperature-controlled laser diode with constant-current driver provides a beam that is free of wavelength hops and amplitude changes, making beam aiming repeatable and allowing point-by-point comparisons of the detected reflectance. The disk spins at high speeds on an encoded shaft, and the assembly is radially stepped to allow inspection of the disk at radial and angular positions while a microprocessor synchronized with the spinning disk collects light data to compile a map of surface reflectance. The polarization may be controlled to enhance image quality for different coatings and improve signal discrimination. Simple logic applied to point-by-point inequalities identifies the nature of physical changes responsible for observed effects. Polarization contrast and time difference contrast images allow visualization of defects and changes in substantially transparent layers well under a quarter wave thickness.

Disk film optical measurement system

A composite lubricant for thin-film magnetic discs comprising perfluoropolyether (PFPE) lubricant and an anti-oxidant, cyclophosphazene lubricant dispersed in a fluoropentane solvent.

Thin film disc lubrication utilizing disparate lubricant solvent

The present invention is a method for bonding a lubricant onto the surface of rotating storage media. In particular, the method bonds reactive and non-reactive lubricants onto the carbon based protective coating of a magnetic storage disk. The lubricant is first applied onto the disk surface through conventional coating techniques, such as dipping, spinning, spraying, or vapor deposition. The thickness of the applied coating is thicker than the final bonded thickness of the lubricant. Typically, the applied thickness of the film is approximately 30 Angstroms. The lubricant coated disk surface is then exposed to low energy electron irradiation. The energy level of the accelerated electrons is below 100 eV. The lubricated film is exposed to a dosage level of approximately 1000 microcoulombs per square centimeter. This dosage level bonds approximately 15 Angstroms of lubricant to the disk surface. The non-bonded or excess lubricant is then rinsed off in a liquid freon or other suitable rinse.

Process for bonding lubricants to a thin film storage media

Controlled laser texturing of a magnetic recording disk is accomplished by use of a textured test band on the disk and an analyzing laser system to provide feedback to the texturing laser. The analyzing laser system determines, from diffracted laser light, the average height of the laser-induced bumps formed in the test band by the texturing laser. The analyzing laser beam is directed to the substrate surface and overlaps a group of individual bumps formed in a repetitive pattern. A scanning linear photodector array receives light diffracted from the surface. The digitized output of the array is the angular distribution of diffracted light intensities and is used to compute the average height of the bumps in the test band. The disk is then translated radially so that the texturing laser is aligned with the region of the disk where the textured landing zone is to be placed. Then, in response to the computed value of average bump height in the test band, a correction signal or signals is output to modify one or more parameters of the texturing laser so that the texturing laser can form bumps of the correct average height in the textured landing zone.

Process and apparatus for controlled laser texturing of magnetic

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Fremont, CA, United States of America

Gerard H Vurens