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. 30, 1997
Filed:
Apr. 17, 1996
Tod L Erickson, San Jose, CA (US);
John P Lauer, Palo Alto, CA (US);
Phase Metrics, Inc., San Diego, CA (US);
Abstract
A preferred embodiment of the present invention comprises two laser sources of different frequency monochromatic light that are time-multiplexed through a beam combiner to produce composite beams that are steered to a gap between a slider and a disk. A reflected light that includes an interference pattern is then directed to an aperture plate that permits a spot of light to be directly detected by a photodiode which reads the intensity. Measurements of the intensity are taken at respective time-points to sample each laser source, and the measured intensities are compared to determine the slider to disk spacing. Since different frequency light will have different intensity for the same spacing, integer ambiguities can be directly resolved. In an alternative embodiment, several photodiode detectors are included with a multi-aperture plate that permits the simultaneous assessment of disk-to-slider spacing at several points of the slider dictated by the placement of multiple composite laser beams and the respective apertures.