Surface particle detection using heterodyne interferometer
US5343290A · kind A · utility
19Cited by
5References
26Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 11, 1992 |
| Grant date | Aug 30, 1994 |
| Priority date | — |
| Expiry date | Jun 11, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/8822
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A heterodyne interferometer is combined with darkfield surface particle detection for improved surface particle detection sensitivity. The probe beam and the reference beam have different wavelengths. The reference beam may either be a real reference beam or a virtual reference beam. The probe beam may be incident at the surface at either a grazing angle or at an angle substantially normal to the surface. The real reference beam is incident at the surface at a grazing angle. The detection may either be conventional heterodyne detection or a combination of heterodyne and Lloyd's mirror detection.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.