Alignment free interferometer and alignment free method of profiling object surfaces
US6473185B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 7, 2001 |
| Grant date | Oct 29, 2002 |
| Priority date | — |
| Expiry date | Apr 18, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/15
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An improved method and apparatus for profiling surfaces is provided. The subject apparatus avoids the earlier used constructions of such apparatus in the normally used Fizeau interferometer form, and instead uses a retroreflector (200) located at the end of the optical path (128) of the beam reflecting off of the surface under test (150) in order to achieve alignment-free surface profiling. In addition, in a second embodiment, a second retroreflector (140′) is used to assure a more accurate result. While in yet another improvement, the retroreflector (200) is selectively moveable in relation to the optical path of the beam, to compensate and correct for a shearing effect resulting from the use of variously sized (thicknesses) flats under test.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.