Finger Clip Oximeter

By driving a red LED (660nm) and an infrared LED (910nm) in turn, the blue line indicates the sensing curve of the receiver to reduced hemoglobin when the hemoglobin does not contain oxygen molecules. From the graph, you can see the reduced hemoglobin against 660nm red The absorption of light is relatively strong, but the absorption length of infrared light at 910nm is relatively weak. The red line indicates the red blood cells with hemoglobin and oxygen molecules. The receiver tube responds to oxygenated hemoglobin. From the figure, it can be seen that the absorption of red light at 660nm is relatively weak, and the absorption of infrared light at 910nm is relatively strong. In the measurement of blood oxygen, the reduced hemoglobin and aerobic hemoglobin are measured by detecting the difference between two types of light absorption at different wavelengths. The measured data difference is the most basic data for measuring blood oxygen saturation. In the blood oxygen test, the two most common wavelengths of 660nm and 910nm actually need to be more accurate. In addition to the two wavelengths, it must be increased, even up to 8 wavelengths. The main reason is that human hemoglobin in addition to reducing hemoglobin In addition to oxygenated hemoglobin, there are other hemoglobins. We often see carboxyhemoglobin. More wavelengths are conducive to better accuracy.