The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 18, 1996
Filed:
Apr. 30, 1993
David W Abraham, Ossining, NY (US);
Anthony P Praino, Poughguag, NY (US);
Mark E Re, Los Gatos, CA (US);
Hemantha K Wickramasinghe, Chappaqua, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method and apparatus for mapping the character and location of small surface variations on a planar surface. Energy is supplied to an object in close proximity to the planar surface to thereby raise the temperature of the object. The object is moved with respect to the planer surface substantially constant. A decrease in temperature of the object is detected when it is in proximity to the variation to define the location and character of the variation. The energy supply may be thermal energy or optical energy but preferably is electrical energy which heats a resistive element. Preferably, the object is the magnetoresistive head of a disk drive assembly. The surface may be that of a magnetic recording material. The change in temperature is detected by monitoring the resistance of the magnetoresistive coil of the head. The energy may be supplied in pulses to obtain higher peek temperatures while avoiding mechanical distortion of the object. It is preferred that the object be positioned with respect to the surface so that when that relative motion between the surface and the object occurs, the object does not contact the surface.