Method and a system for measuring fluid flow movements by a laser-doppler technique
US5361769A · kind A · utility
Inventor
Key dates
| Filing date | Apr 21, 1993 |
| Grant date | Nov 8, 1994 |
| Priority date | — |
| Expiry date | Apr 21, 2013 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/0261
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention relates to a method and to a system for reducing the distance-dependent amplification factor when measuring fluid flow movements with the aid of an image-producing laser-Doppler technique, in particular when measuring blood perfusion through tissue. A laser beam source (1) directs a laser beam (2) onto a measurement object (5), which scatters and reflects the beam (2). The reflected light is received by a detector (9) which senses the broadening in frequency caused by the Doppler effect. One or more lenses (12: 15, 16) are placed in the path of the beam (2) and are intended to maintain constant the number of coherence areas on the detecting surface of the detector and independent of the distance between detector and measurement object.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.