Interferometric distance measuring method for measuring surfaces, and such a measuring arrangement
US9677870B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 25, 2012 |
| Grant date | Jun 13, 2017 |
| Priority date | — |
| Expiry date | Jun 25, 2032 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B9/0209
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A distance measuring method for measuring surfaces uses a laser source having a frequency that can be modulated to tune a wavelength of a laser beam in a wavelength range. The laser beam is generated with a coherence length to provide a measuring beam and is emitted at the surface, located within a specified distance range, as a measuring beam. The measuring beam is back-scattered by the surface and is received again and used to interferometrically measure the distance from a reference point to the surface. The specified distance range lies at least partly outside of the coherence length. One portion of the laser beam is temporally delayed with respect to another portion, such that the one optical path difference caused by the delay matches the optical path difference that corresponds to a distance in the specified distance range plus or minus the coherence length of the laser.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.