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:
Oct. 26, 1993
Filed:
Nov. 12, 1991
Michael Mager, San Jose, CA (US);
Boris Slutsky, Palo Alto, CA (US);
Guziktechnical Enterprises, Inc., San Jose, CA (US);
Abstract
An apparatus employs the phenomenon of frustrated total internal reflection for measuring nanometric distances. It includes a two-piece glass reference disk (200) consisting of an inner disk (202) and a coupling lens (212). The inner disk (202) contains a convex spherical surface (204) and a flat bottom surface (206). The coupling lens has a planar top surface (214) and a concave spherical surface (216). It is fixed over the inner disk which is rotated by a spindle (208). Aligned prisms (218 and 220) have polished planes (222 and 224) and polished surfaces (230 and 232). These surfaces provide optical contact of the prisms with the planar top surface of the coupling lens. A magnetic head (238) is suspended over the flat bottom surface of the inner disk. Other configurations of the reference disk and optical prisms are possible. One of the variations of the optical system contains a colored-light source (248), aimed at the polished prism surface at essentially normal incidence, a beam expander ( 250), placed between the light source and the polished prism surface, and a TV camera (252), which is positioned opposite the polished prism surface (222). As the spindle rotates the inner disk, the magnetic head floats on an air cushion created by the surface of the glass disk. A light beam (242), generated by the light-source, is converted into a wide parallel beam (244), which is directed at the surface of the magnetic head. A reflected beam (246) is received by the TV camera. The spacing between the magnetic head and the disk surface can be calculated from the drop in intensity of reflected light.