There are six common types of thermometers.
Currently common contact measurement mainly using mercury thermometers, electronic thermometers; non-contact measurement refers to the use of infrared thermometers, including ear thermometers, forehead thermometers, infrared imaging thermometers.
The body temperature can be measured by both contact and non-contact methods. Contact measurement includes three types of temperature measurement, i.e., direct measurement through the mouth, armpit and anus, where the temperature of the mouth is 36.5°C to 37.3°C, the armpit is 0.5°C lower than the mouth, and the anus is 0.5°C higher than the mouth. The non-contact method is through infrared thermometry, the measurement is the body surface temperature, through an algorithm to derive the actual body temperature of the person.
Expanded Information:
1, mercury thermometer
cheap, easy to use, almost everyone will, and mercury thermometer easy to clean, easy to disinfect, and at the same time, the mercury thermometer is the "gold standard" for measuring body temperature.
But the shortcomings are also difficult to ignore, including the measurement time is long, generally 10 minutes; glass material, easy to break; broken mercury will pollute the environment, is not good for health; need to be measured with the cooperation of the people, is not suitable for mental illness, such as the behavior of the uncontrolled crowd to use and so on.
2, electronic thermometer
The use of methods and precautions and mercury thermometer is almost the same, are placed under the tongue, armpit or rectum, the most in line with the public's habit of use. However, it has the disadvantage that it takes slightly longer to measure the body temperature, and the time required for different brands ranges from 30 seconds to more than 3 minutes.
In addition, diet, strenuous exercise, bathing, etc. will affect the results of the measurement, you need to wait 30 minutes before measuring. The accuracy of the electronic thermometer will also be affected by the electronic components, battery power supply conditions and other factors.
3, infrared thermometer
Infrared thermometer is a use of radiation to measure the human body temperature meter, which uses infrared sensors only absorb the infrared radiation from the human body and does not emit any rays to the outside world, through the non-contact method of sensing the human body temperature. The infrared thermal radiation from the human body is gathered on the detector, which converts the radiant power into an electrical signal that can be displayed in temperature units after being compensated for the ambient temperature.
Currently on the market common infrared temperature measurement instruments are mainly ear temperature gun, forehead temperature gun.
4, ear thermometer
Measurement of the temperature of the tympanic membrane, the tympanic membrane can respond to the body's core body temperature, the most reflective of the body's true body temperature, but also most of the medical places to replace the mercury thermometer used to determine the basis of the body temperature.
But because the human ear canal is not straight, infants and young children under the age of 3 need to lift their ears to the lower back and lower back when measuring their ear temperature, and adults over the age of 3 or older should lift their ears to the upper right in order to place the ear thermometer in the correct position.
The ear canal diameter of small children under 6 months of age is small, making the use of an ear thermometer inappropriate. Suffering from otitis externa, otitis media and other ear diseases, swimming, bathing when the ear hole is wet is also not suitable for the use of ear thermometer. In addition, if the measurement is repeated several times in a short period of time, the ear thermometer itself will affect the temperature of the ear canal, which will also affect the accuracy of the measurement results.
5, forehead temperature gun
Mainly rely on the sensor to receive infrared rays from the body to determine the body temperature. Ideally, the measurement should be accurate, but there are many factors affecting the room temperature, the dryness of the skin will affect the results, just wash your face or take off the IcePo stickers directly measured body temperature does not reflect the true temperature of the human body.
But the forehead temperature gun is convenient and fast, often used in kindergartens, airports, train stations, such as high traffic, need to quickly screen patients with fever.
6, infrared imaging thermometer
Currently this new thermometer also joined the epidemic prevention and control war. According to radiation theory, any object as long as the absolute zero (-273 ℃) above, there is thermal radiation.
The working principle of infrared thermography is based on the energy radiated by the object to measure the temperature. The use of infrared detectors and optical imaging objective lens to accept the measured target of infrared radiation energy distribution graph reflected in the infrared detector photosensitive element, so as to obtain the infrared thermal image, this thermal image corresponds to the object surface heat distribution field.
In layman's terms an infrared imager is the invisible infrared energy emitted by an object into a visible thermal image. Different colors in the image represent different temperatures of the object being measured.
Baidu Encyclopedia - Thermometer