Interferometer and method for measuring the distance of an object surface with respect to the surface of a rotating disk
US5600441A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1995 |
| Grant date | Feb 4, 1997 |
| Priority date | — |
| Expiry date | Jan 31, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/6011
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Optical method and means for high-speed characterization of the distance between a substantially transparent plane-parallel disk (20) in rotation about an axis (21) perpendicular to its largest surface, and a substantially flat object (30) that is nearly in contact with the disk surface (25). A collimated light beam (2) is first divided into two parallel, spatially separated and orthogonally polarized beams (5,7) which are incident upon the disk surface (25) at Brewster's angle. One beam (5) passes through the disk unreflected and impinges upon the surface of object (30) and reflects back from object (30). The other beam (7) is partially reflected from the bottom surface of the disk (25) and is subsequently recombined with beam (5) and caused to interfere. Optical means (90,91,100,110,150) together with electronic detection and analysis means (130,131; 120,121; 99) determine the phase of the interference. At the same time, a second pair of beams (6,8) is created by division of the collimated source light (2) into two parallel, spatially separated beams having a polarization chosen so that they both reflect from the disk surface (25) and a spatial position such that neither beam (6,…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.