Apparatus for measuring nanometric distances employing frustrated total internal reflection
US5257093A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 1991 |
| Grant date | Oct 26, 1993 |
| Priority date | — |
| Expiry date | Nov 12, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B33/10
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
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 d…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.