Common path, interferometric systems and methods using a birefringent material for topographic imaging
US5973784A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 8, 1998 |
| Grant date | Oct 26, 1999 |
| Priority date | — |
| Expiry date | Jan 8, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/70
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Common path, two beam interferometers and interferometric measurement systems employ a voltage controlled variable phase retarder enabling rapid stepping of the relative phase between two interfering optical beams by suitable control of the voltage. The beams need not be laterally separated. A compact beam expander with a ball lens is preferably included. The system is compact enough to be contained in a hand-held unit. The system can be used for surface mapping, testing of optical components and detecting the motion of mechanical objects, for example. It is particularly well suited for the mapping of the skin of a live subject. An optimum fringe period and optimum illumination wavelengths for imaging skin are disclosed, enabling the topography of substantial areas of human skin to be rapidly and accurately measured, in times on the order of one-tenth of a second. Methods of conducting interferometric analysis are disclosed, as well.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.