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:
Dec. 12, 1995
Filed:
Nov. 05, 1993
Tadashi Fukuzawa, Setagaya-ku, Tokyo, JP;
Teiji Hisano, Fujisawa-shi, Kanagawa-ken, JP;
Kohichi Ikarugi, Chigasaki-shi, Kanagawa-ken, JP;
Tetsuji Morita, Fujisawa-shi, Kanagawa-ken, JP;
Kohki Noda, Fujisawa-shi, Kanagawa-ken, JP;
Other;
Abstract
A high-sensitivity apparatus having simple constitution that measures the flying height of a magnetic head. Light emitted from a white light source 25 is directed to the gap between a disk 23 and a head 21, and subjected to multiple reflection between the disk 23 and the head 21. Reflected light from an opaque object, which may be either the disk 23 or the head 21, is divided into at least three components having respective wavelength regions which are directed to different photodetectors 35, 36, and 37 for the respective wavelength regions. An estimation device 38 estimates the flying height of the head according to the least-square method from the outputs of the photodetectors using functions prepared in advance for the respective wavelength regions, and correlates the disk-head gap and the reflected light intensities detected by the respective photodetectors. Real-time calculation according to the least-square method is performed by means of a table look-up technique or a tracking servo technique.