基于差分吸收检测技术的非分散红外CO2呼吸气体传感器

采用非分散红外(non-dispersive infrared,NDIR)气体传感器实时检测呼吸气体中的CO2气体浓度,进而反映人体运动机能和代谢功能等身体状态,可以满足人类日益增强的对自身健康状况进行了解的需求.利用电调制微机电系统(micro-electro-mechanical system,MEMS)光源和双通道热释电传感器分别作为红外光源和探测器,采用气室结构设计和压电微泵相结合的方法为传感器提供稳定的气体流速,设计出红外呼吸CO2气体传感器.通过测量不同CO2标准气体浓度下热释电传感器参考通道和测量通道的电压比值进行传感器标定,获得了在室温下、检测量程0％～8％内,绝对误差小于0.5％,相对误差3％,系统响应时间小于1.5 s的传感器,提高了基于NDIR气体传感器检测呼吸气体的抗干扰能力,可望满足运动机能和代谢功能检测等应用对CO2气体监测的需求.

Non-dispersive infrared CO2 breathing gas sensor based on differential absorption detection technology

The non-dispersive infrared (NDIR) gas sensor is used to detect the concentration of respiratory CO₂ in real time,and thereby reflect the physical state of the human body''s motor function and metabolic function, which can meet the growing needs of people to understand their own health conditions. In this paper, an electrically modulated micro-electro-mechanical system(MEMS) light source and a dual-channel pyroelectric sensor are used as an infrared light source and detector respectively. The gas chamber structure design and the piezoelectric micropump are combined to provide a stable gas flow rate for the sensor. By measuring the voltage ratio of the reference channel and the measuring channel of the pyroelectric sensor under different CO₂ concentrations, the sensor calibration is obtained at room temperature, in the range of 0%~8% of the detection range, the absolute error is less than 0.5%, and the relative error is 3% and the response time of the gas sensor is less than 1.5 s. The anti-interference ability of the NDIR gas sensor to detect the breathing CO₂ is improved, and it is expected to meet the demand for CO₂ gas monitoring in applications such as motor function and metabolic function detection.