Design And Evaluation Of Reflection Mode SpO₂ Simulator

The application of pulse oximeter is a representative of the development of modern medical technology.Its research and development aim to continuously and non-invasively monitor human blood oxygen saturation,providing convenient and effective physiological parameters for doctors’clinical diagnosis.At present,the mainstream pulse oximeter on the market is transmission-type.Since the transmission-type pulse oximeter has limitations on the measurement site,it is not applicable to measurement of most body surfaces such as the abdomen,head,and chest surface.Many scholars at home and abroad have studied the reflection-type pulse oximeter,most of which are used to measure the oxygen saturation of the brain.There are also a number of scholars who have conducted studies on reflection-type pulse oximeter,but very few of them have been put into production.With the vigorous development of large-scale health industrialization and the demand for data indications in clinical medicine,the demand for research and development of reflection-type pulse oximeter is also growing.In order to improve the accuracy of the reflection-type pulse oximeter in product development,design and production,it is necessary to have an instrument that can simulate human oxygen saturation（called pulse Sp O₂ simulator）.It can assist in the development,design and production process of the pulse oximeter.But in the market,it is difficult to find a suitable pulse Sp O₂ simulator for developing a reflection-type pulse oximeter.This paper aims to design a reflection-type pulse Sp O₂ simulator that can be fully applicable to the reflection-type pulse oximeter.This paper discusses the detection principle of pulse oximeter and analyzes the principle and design idea of pulse Sp O₂ simulator based on the principle of pulse oximeter.The idea of this design is using the microprocessor technology to design an adjustable pulse wave electrical signal and load the signal onto the liquid crystal material.Due to the photoelectric properties of the liquid crystal material,the overall absorbance of the liquid crystal will change with the pulse wave electrical signal,thereby simulating the desired pulse oximetry signal.At last to make a reflection-type pulse Sp O₂ simulator which is applicable to the reflection-type pulse oximeter.After preparing the reflection-type Sp O₂ simulator,a reflection-type pulse oximeter was used to calibrate the reflection-type Sp O₂ simulator.In order to verify the calibration results,another pulse oximeter was selected for comparison test.And the test shows that the reflection-type Sp O₂ simulator designed can be applied to the reflection-type pulse oximeter for functional testing.The reflection-type Sp O₂ simulator designed in this paper uses a liquid crystal panel as a simulated finger,which is easy to simulate different oxygen saturation values;the calibration function is opened for users,it allows the user to determine the R-value curves as necessary.The reflection-type Sp O₂ simulator designed in this paper provides theoretical and data reference for product development,design and production of reflection-type pulse oximeter.