Side illumination in interferometry
US9746315B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 8, 2015 |
| Grant date | Aug 29, 2017 |
| Priority date | — |
| Expiry date | Jan 29, 2036 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N13/254
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Side illumination is combined with scanning interferometry to provide a means for measuring with a single data-acquisition scan surfaces that contain sections suitable for interferometric processing as well as sections that are not suitable because of lack of fringes produced by the measurement. In the sections where no fringes are produced, the irradiance detected during the scan is processed using a depth-from-focus mapping method to yield a corresponding measurement. The result is a complete profilometric measurement of the sample surface with a single scan. In addition, by increasing sample irradiance through side illumination, the structural features of the sample become markedly more visible than when illuminated only by the object beam of the interferometer, which greatly facilitates finding focus and identifying regions of interest for the measurement.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.