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Optical Interference Technique for Measuring Real Area of Contact at Head/Tape Interface Disclosure Number: IPCOM000043822D
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-05

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Related People

Bhushan, B George, OE Van Evera, KF [+details]


In a tape drive, when a tape rubs against a head during start/stop or high asperity interaction, frictional force is produced. Efforts are made to minimize the frictional force which primarily depends on the real area of contact and strength of the junctions. For tape development and for diagnostic purposes, it is important to measure the real area of contact. An optical interference technique is developed and described here. When an irregular reflective surface is held in intimate contact with an optically flat surface, interference fringes occur wherever the separating distance is equal to one half of the wavelength of the light used. The high points of the irregular surface, which make up the area of contact, appear as black spots.