Opto-chemical Sensor for Oxygen Measurements in Sealed Packages
Publication from Health
Bizzarri A., Gruber W., Trettnak W., Dolezal C., Ribitsch V.
Proceedings of the 4th International Conference and Exhibition on Optoelectronics, Optical Sensors and Measuring Techniques, 193-198, 5/2000
An opto-chemical sensor for contact-less oxygen measurement inside sealed packages has been developed. The sensor is based on the principle of the luminescence quenching of a dye. The indirect measurement of the luminescence lifetime by means of a phase-shift technique is used for oxygen sensing. The measuring system consists of an oxygen sensitive element, which can be included inside the outer wrapper of a sealed package, and of an opto-electronic read-out module. This consists of three units: 1) a simple optic module, based on semiconductor devices (light emitting diodes and photo-diodes), filters and glass lenses; 2) an infrared thermometer to measure the temperature of the oxygen-sensitive element; 3) system electronics for data processing, temperature compensation and calibration procedures. Preliminary tests performed on this new instrument proved the suitability for contact-less oxygen measurements inside sealed packages. Therefore, it can be used for on-line non-destructive quality controls at the processing line of packaging industries and for leakage inspection of sealed packages throughout the distribution chain from the manufacturer to the distributor. Furthermore, since measurements are reversible and without consumption of oxygen, this sensor can also be profitably used in packaging technology and food research to investigate oxygen diffusion and permeation through the packaging material.