SCIENTIFIC AND PRACTICAL JUSTIFICATION OF DESIGN AND CALCULATION OF OPTICAL PART OF LASER PULSOXIMETER PSO3-2KL

Abstract

Background. A significant part of the work of domestic and foreign researchers is devoted to devices with finger sensors operating in transmitted light, based on the Booger – Lambert – Behr law. Such designs are popular due to the use of cheaper LED sensors, but at the same time they also have a number of disadvantages, the main one being low measurement accuracy. In this regard, the author of this article considers it relevant to develop a pulse oximeter with a backscattering sensor (surface sensor), whose work is based on the use of Lambert's law. The purpose of the work: to find a solution to an important medical problem of increasing the accuracy of measurements and obtaining extended reliable information in pulse oximetry through the use of new technical solutions in the design of the optical part of the laser pulse oximeter sensor. Materials and methods. The technique of finding the optimal position of laser diodes and photodiodes relative to each other and the skin, as well as the design and position of the barrier elements, which serve as slots in the optical plate, is applied. Results. Based on the above optical calculations, a design of a sensor operating in backscattered light is proposed. Conclusions. Combining three lasers with the necessary wavelengths and a photodetector (PD) in one small-sized surface sensor will allow you to get rid of significant measurement errors, compared with finger sensors, in which compression, pinching and even rupture of blood vessels can occur.

Keywords

• laser sensor
• three-wave laser pulse oximeter
• spectral dependence of the absorption coefficient
• dependence of light absorption on the wavelength of radiation
• hemoglobin
• dependence of radiation on the distance to the source
• photoplethysmographic signal
• photodetector