The working principle of the nail oximeter: by sequentially driving a red LED (660nm) and an infrared LED (910nm), the blue line indicates the induction curve of the receiving tube to the reduced hemoglobin when the hemoglobin does not carry oxygen molecules.
It can be seen that the absorption of reduced hemoglobin to 660nm red light is relatively strong, while the absorption length of 910nm infrared light is relatively weak. The red line indicates the induction curve of oxyhemoglobin when the receiving tube has hemoglobin and red blood cells with oxygen molecules. The absorption of red light at 660 nm is relatively weak, and the absorption of infrared light at 910 nm is relatively strong. In blood oxygen measurement, the difference between reduced hemoglobin and oxygenated hemoglobin by detecting the difference between the two types of light absorption at different wavelengths is the most basic data for measuring blood oxygen saturation. In the blood oxygen test, 660nm and 910nm are the two most common wavelengths. In fact, to achieve higher accuracy, in addition to two wavelengths, even up to 8 wavelengths, the main reason is that human hemoglobin is not only reduced to hemoglobin. In addition to oxyhemoglobin, there are other hemoglobins, we often see carboxyhemoglobin,
Post time: Jun-15-2022