The Finger Pulse Oximeter drive a red LED (660 nm) and an infrared LED (910 nm). The blue line indicates the induction curve of the receiver tube to the reduced hemoglobin when the hemoglobin is not an oxygen-containing molecule. The reduced hemoglobin Can be seen from the graph. The absorption of red light at 660 nm is relatively strong, while the absorption length at infrared light at 910 nm is relatively weak. The red line indicates the sensor-to-oxygenated hemoglobin sensing curve of hemoglobin with hemoglobin. With oxygen molecule. From the figure, it can be seen that the absorption of red light at 660 nm is relatively weak, and the absorption at 910 nm is relatively strong. In the measurement of blood oxygen, the reduction of hemoglobin and aerobic haemoglobin, By detecting the difference between the two different wavelengths of light absorption, the measured data difference is the most basic measurement of blood oxygen saturation data. In the blood oxygen test, the two most comm On wavelengths at 660nm and 910nm, in fact, to achieve higher accuracy, in addition to two wavelengths but also to increase, even up to 8 wavelengths, the main reason is that in addition to the reduction of human hemoglobin In addition to hemoglobin and oxyhemoglobin , there are other hemoglobins. We often see carboxyhemoglobin, and more wavelengths help you do better