How accurate does an infrared thermometer need to be in order to be used as a medical grade thermometer?
Classification of thermometers: contact and non-contact thermometers
Common methods of measuring human body temperature are mainly categorized into two main types, namely, contact and non-contact.
Contact measurement of common mercury thermometer, home electronic thermometer and medical temperature probe temperature measurement, etc., through the contact with the relevant parts of the body to measure the body temperature, such as armpits, mouth, etc., the contact measurement accuracy of 0.1 degrees or so, high precision, to meet the clinical diagnosis of rapid and accurate measurement of body temperature requirements.
However, because of the direct contact with the human body, each measurement may be infected by germs, and need to be frequently sterilized, and the measurement speed is slow, and can not be a large number of human body for continuous rapid measurement. For example, a mercury thermometer needs to be placed under the armpit for 15 minutes, while home electronic thermometers and medical temperature probes also need 3 to 5 minutes of measurement time.
Home electronic thermometers
The most typical method of non-contact measurement is infrared thermometry. Since the discovery of the principle of infrared radiation, infrared technology has been widely used in temperature measurement. Infrared thermometers are characterized by a wide temperature measurement range, fast response speed and high sensitivity. Infrared ear thermometers, infrared forehead thermometers and infrared screening devices are all non-contact thermometers.
However, compared to contact temperature measurement, the accuracy of non-contact temperature measurement is lower, the higher accuracy of non-contact thermometers in about 0.2 degrees, the poorer temperature measurement error in 1 degree or even more than 1 degree. The temperature measurement time is about 5 seconds, which is very fast, so it is widely used in daily temperature measurement and industrial temperature measurement.
Infrared temperature measurement error is greater than the contact temperature measurement is that infrared temperature measurement is susceptible to atmospheric conditions, ambient temperature, the measured object surface emissivity and other environmental factors. Such as water vapor in the air, dust particles, etc. on the infrared radiation has a strong absorption effect; target object near the source of heat radiation energy on the target object radiance caused by interference; ambient temperature on the temperature measurement device sensing the target object radiance will have an impact. In addition, with the increase of the temperature measurement distance, the ability of the temperature measurement device to sense the object radiance will also be affected. Therefore, in the case of a certain temperature of the object to be measured, with the measurement distance, ambient temperature and other factors are different, the temperature of the object sensed by the temperature measuring device is also different, thus reducing its measurement accuracy.
Handheld infrared thermometer and other temperature measurement products on the market today, easily affected by the measurement distance and ambient temperature, the measurement error is often about 1 degree, can only be used to roughly determine the state of the human body, can not meet the clinical diagnosis of rapid and accurate measurement of body temperature requirements.
Handheld infrared thermometer
Three major categories of infrared thermometer
According to the different uses and accuracy, infrared thermometer can be broadly divided into medical-grade infrared thermometer, consumer-grade infrared thermometer and industrial-grade infrared thermometer.
Strictly on the division, medical-grade infrared thermometer on the highest precision requirements, precision needs to be between 0.1 and 0.2 degrees, high-precision infrared ear thermometer can reach the standard of medical-grade temperature measurement, but in order to avoid cross-infection, hospitals need to increase the disposable sheaths when the use of ear thermometer gun; consumer-grade second, accuracy of 0.5 or so to meet the temperature of our daily needs, such as the mother of a baby used to measure the temperature of the bath water, and so on. Currently on the market, most of the handheld infrared forehead temperature gun, the price between one hundred and one thousand dollars, precision in most of the 0.3 degrees or so, belongs to the consumer-grade infrared thermometer; industrial-grade the lowest, the general maximum permissible error of ± 1 ℃ or more, and measuring distance farther.
