Abstract: The sensor system for the detection of chemical substances has a spiral optical waveguide which produces an evanescent field penetrating into the adjacent medium, a light source for coupling light into the waveguide, and a detecting circuit for receiving light from the waveguide and producing an output signal reflecting the sensed chemical substance. The waveguide has the form of a bifilar, non-crossing spiral. It consists of an incoming or decreasing spiral segment and an outgoing or increasing spiral segment continuously bound by a central semi-circular segment.

Abstract: A device for the combined measurement of the arterial oxygen saturation and the transcutaneous CO2 partial pressure on an ear lobe comprises a sensor. The sensor has means for pulse oximetric measurement of the arterial oxygen saturation, means for measurement of the transcutaneous CO2 partial pressure and means for warming a sensor contact surface intended for contact with the ear lobe. The device makes simple and reliable measurement of the arterial oxygen saturation and the transcutaneous CO2 partial pressure possible on an ear lobe.

Abstract: In a method for the non-invasive determination of the oxygen saturation in tissue supplied with blood, the tissue is irradiated with red and infrared light and the DC and AC components of the emerging light are measured. During a first time interval, a calibration factor k is determined from the DC and AC components of the emerging light. During a second time interval, the oxygen saturation in the tissue is computed progressively from the DC components of the emerging light and the determined calibration factor k.