Device for determining the concentration of at least one gas component in a breathing gas mixture

A device for determining a concentration of a gas component in an inhaled gas or in an exhaled gas of a living being, the device comprising:

• a radiation source configured to emit light or heat radiation in a radiation direction in a wavelength range of lambdal (λ1)=2.5 μm to lambda2 (λ2)=14.0 μm, wherein the radiation source is configured as:
• a flat radiator, as a diaphragm radiator or as a radiation element and is configured with an essentially planarly configured radiating surface;
• or
• a light-emitting diode (LED) configured with an essentially planarly configured radiating surface;
• and
• the radiating surface is configured for mainly uniform radiation over the radiating surface;
• a detector array with at least two detector elements configured to detect the radiation generated by the radiation source;
• at least two bandpass filter elements each of the filter elements being arranged at one of the at least two detector elements;
• at least one optically reflecting element having a flat configuration and arranged opposite the radiation source;
• and
• a control unit configured to control operation of the radiation source and to detect the signal of the at least two detector elements, wherein:
• at least one of the at least two bandpass filter elements is configured to be optically transparent for infrared radiation which is absorbed by a measured gas;
• at least one of the at least two bandpass filter elements is configured to be optically transparent for a radiation that is not absorbed by the measured gas;
• at least one of the two detector elements with at least one of the bandpass filter elements is arranged in an angular arrangement at an angle in a range of 20° to 80° in relation to an axis extending through the radiation source parallel to or identical to the radiation direction of the emission of the radiation source;
• the radiating surface is perpendicular to the axis;
• the radiating surface comprises an area in a range of 2.0 mm2 to 10 mm2;
• each of the at least two detector elements is arranged at a first distance from the axis in a range of 0.1 mm to 10.0 mm;
• each of the at least two bandpass filter elements is arranged at a second distance from the axis in a range of 0.1 mm to 10.0 mm;
• the detector array is arranged on a same side, with respect to the oppositely arranged reflecting element, as the radiation source and is arranged adjacent to the radiation source;
• the at least two detector elements are arranged at a reflecting element distance from the reflecting element in a range of 0.1 mm to 5.0 mm;
• and
• the reflecting element distance is a distance directly in a range of or along the axis extending from the reflecting element between the at least two detector elements.