Since the outbreak of SARS in 2003, in order to prevent and control the epidemic, it is necessary to measure the body temperature of a large number of people. In the past, the contact mercury thermometer took a long time to measure, which generally took more than 5 minutes. After the measurement in the epidemic prevention stage, it needs to be disinfected before it can be reused. People need a fast, accurate and safe method to measure body temperature It has the following characteristics
Since the outbreak of the new virus in 2020, a large number of infrared thermometers are still used in the prevention and control of body temperature in China. Although the development of civil infrared thermometers has been nearly 20 years, its temperature measurement principle has not made a breakthrough. It is still composed of optical system, photoelectric detector, signal amplifier, signal processing, display output and other parts.
The optical system gathers the infrared radiation energy of the target in its field of view. The size of the field of view is determined by the optical parts of the thermometer and its position. The infrared energy is focused on the photodetectors and converted into corresponding electrical signals. After the amplifier and signal processing circuit, the signal is converted into the temperature value of the measured target after being corrected according to the algorithm of instrument internal therapy and target emissivity.
All objects above absolute zero will radiate infrared rays by themselves. The function of infrared thermometer is to collect the infrared emitted by objects. The main factors affecting temperature measurement are material type, surface roughness, physical and chemical structure and material thickness.
The infrared thermometer used to measure human body temperature is called human body thermometer. But it must be clarified that there is no special medical or industrial infrared thermometer, because the manufacturing principle of infrared thermometer is the same. There are only high precision, high range coefficient ratio, high performance infrared thermometer and low precision, low distance coefficient ratio and low performance infrared thermometer.
The main factor affecting the measurement accuracy is to set the emissivity of the infrared thermometer at 0.95 (the emissivity of human skin is generally this value, even if there is a difference, the influence is only within 0.3 degrees), which is in line with the requirements of human body temperature measurement. When measuring the body temperature, the emissivity is generally adjusted at 0.95, which is the most accurate temperature measurement.
After comparing the results of the measurement at the test point with that of the thermometer at home, it is often said that the temperature is not accurate, which is due to the operation errors of many testers. Because the influence of the measurement is the surface temperature of the human body, the measured temperature value and the actual value will be different due to the influence of the environment and the moving distance of the human body. In order to ensure the accuracy of the measurement, it is recommended to pay attention to the following points when using.
