| Popis: |
In most optical-based oxygen sensors, fluorescent quenching is used as the sensing principle. Intensity and lifetime are two known measurement techniques that are employed to quantify the measured parameter. The lifetime measurement technique has superior features such as little or no sensitivity to changes in the optical path, degradation of the film or photo-bleaching. In this study, we conducted an experiment to analyze the performance of both the intensity and lifetime measurement techniques of a platinum-porphyrin fluorescent film, the sensing material, under different concentrations of oxygen. A prototype that deploys an analog front-end, a light emitting diode driver, and a power management block is implemented on a printed circuit board with commercial off-the-shelf components. The system resolves changes in oxygen pressure from 0.5 mmHg to 500 mmHg with a power consumption of 132 mW. This system could be potentially used to measure the concentration of oxygen diffused through the skin, also known as transcutaneous measurement of oxygen. These measurements are key to developing more sophisticated read-out circuits for reliable and sensitive medical purpose transcutaneous oxygen sensing. |
