Thermal measuring and testing – Leak or flaw detection – With heating or cooling of specimen for test
Patent
1993-04-30
1996-06-18
Gutierrez, Diego F. F.
Thermal measuring and testing
Leak or flaw detection
With heating or cooling of specimen for test
374 7, 374141, 374120, 374164, 374137, G01N 2572, G01N 2570
Patent
active
055271103
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.
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R. E. Fontana, Jr., D. E. Horne and H. Sussner, "Disk Asperity Detector" Aug. 1983, IBM Technical Disclosure Bulletin vol. 26 No. 3A pp. 1278-1280.
Abraham David W.
Praino Anthony P.
Re Mark E.
Wickramasinghe Hemantha K.
Aker David
Drumheller Ronald L.
Gutierrez Diego F. F.
International Business Machines - Corporation
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