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:
Sep. 12, 1989
Filed:
Jun. 28, 1988
Masahiro Kubo, Yokohama, JP;
Yasuo Ohtsubo, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
In a magnetic disk apparatus according to the present invention, a slider has a sliding surface and a reflecting surface. The height of the reflecting surface from the magnetic disk is greater than that of the sliding surface from the disk, when the slider flies above the disk, so that there exists a minute difference in level between the sliding surface and the reflecting surface. The flying height of the sliding surface of the slider from the magnetic disk is measured. When the magnetic disk is rotated, the slider flies from the disk. In this state, a reference flying height, i.e., the flying height of the reflecting surface from the magnetic disk is measured by the optical interference process. Then, the minute difference is substracted from the measured reference flying height to obtain the flying height of the sliding surface of the slider from the magnetic disk. According to the invention, even if the minimum flying height of the sliding surface of the slider is shorter than 0.1 micrometer, the measurement can be effected by the optical interference process. In general, moreover, a minute flying height between a fixed datum plane and an object flying above the datum plane can be measured accurately.