Phase modulation spectroscopic system
US5187672A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 22, 1991 |
| Grant date | Feb 16, 1993 |
| Priority date | — |
| Expiry date | Jan 22, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/06113
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A phase modulated spectroscopy (PMS) system for detecting a pathophysiological condition in a subject includes two laser diodes emitting radiation at wavelengths of about 754-760 nm and 816-840 nm. These two laser diodes are modulated sinusoidally at about 220 MHz. The signals from each laser diode are brought to the subject by a bifurcated plastic optical fiber of 1 mm diameter. After transmission through the subject, the signals are detected by a Hamamatsu R928 photomultiplier (PMT), which generates two experimental signals. The experimental signals are compared to a reference signal in a phase detector. The respective phase shifts experienced by the signals are combined to form sum and difference signals, which are correlated to a pathophysiological condition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.