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:
Jun. 10, 1997
Filed:
Sep. 01, 1995
Christopher A Lacey, San Diego, CA (US);
Kenneth H Womack, San Diego, CA (US);
Phase Metrics, San Diego, CA (US);
Abstract
An apparatus and method for measuring the space between a transparent member such as a disk, and reflective member such as a slider, by detecting a change of polarization of a reflected light beam. The apparatus includes a light source that emits a light beam. The light beam is circularly polarized and directed onto the disk and reflected off of the interface between the disk and the slider. The reflected light beam is split into four separately polarized beams by a beam splitter/polarizer assembly. The four light beams have varying intensities that are measured by photodetectors. Stokes parameters are computed from electrical signals that are generated by the photodetectors. The Stokes parameters correlate to the change in polarization of the reflected light beam. Ellipsometric parameters delta and psi are computed from the Stokes parameters. The thickness of the space and the complex index of refraction (n and K) of the slider are computed from the delta and psi parameters, typically by computing two separate sets of ellipsometric parameters at two different spacing thicknesses.