The glass thermometer is the most common type of thermometer. It keeps the mercury column that rises as the body temperature stays in place, which is convenient for users to observe at any time. Because the structure of the glass is dense and the performance of mercury is very stable, the glass thermometer has the characteristics of accurate display and high stability. It also has the advantages of low price and no external power supply. It is deeply trusted by people, especially medical workers. However, the defects of the glass thermometer are also obvious, easy to break, there is the possibility of mercury pollution, the measurement time is relatively long, it is inconvenient to use for patients with severe illness, the elderly, infants, etc., and the reading is more complicated.
Multifunctional infrared thermometer
The multifunctional infrared thermometer can measure ear temperature and forehead temperature. The dual function mode is suitable for measurement and use in different situations:
Ear temperature. The thermometer is generally used in the armpit, mouth, rectum, etc. In practical applications, people generally feel inconvenient or uncomfortable. The ear thermometer measures the temperature of the human body in a non-contact manner by measuring the radiation brightness of the eardrum. The principle is shown in Figure 2. Just point the probe at the inner ear canal and press the measurement button to get the measurement data in just a few seconds. It is very suitable for patients with severe illness, the elderly, infants and young children. However, at the initial stage of use, the user may not be familiar with this operation method, and may obtain several different measurement data. Generally speaking, the measured maximum value is the required data. The user will be more satisfied with this thermometer after being familiar with it. Babies within 10 months and users who have otitis media are more special. Because the baby's ears and ear canals are smaller and the ear canals are more curved than adults, ear temperature measurement is more difficult. Because otitis media has fluid in the ear canal, it will greatly affect the accuracy of the ear thermometer, so users of otitis media are not suitable to use the ear thermometer.
Ear temperature and forehead temperature are both measured by infrared. The forehead temperature is reflected by the infrared radiation on the surface of the forehead and compared with the spectral temperature correspondence table to obtain accurate temperature values. There are also many infrared thermometers that also measure ear temperature and forehead temperature. Forehead temperature Collecting body temperature at the forehead is convenient, simple, and fast. A measurement time of a few seconds is usually sufficient and quite accurate. However, its professionalism is high, it is not convenient for popularization, and it is not suitable for home users. When the room temperature exceeds 25 degrees Celsius and the room temperature is less than 20 degrees Celsius, the thermometer is susceptible to environmental temperature, including sweating, air conditioning, etc. The acquisition temperature has a certain effect.
New and evolving technologies have brought a very strange type of thermometer, called a sheet thermometer or a dot matrix thermometer. This thermometer is the size of a business card, 6-7 cm long and 0.5 cm wide. It is covered with neatly arranged dots with numbers. After the temperature test is performed, all the dots below a certain value will be darkened, and the rest of the dots will not change color. The user can determine the body temperature based on the above changes. This kind of thermometer is not expensive, small in size, easy to carry and store, and has very little pollution. It is especially suitable for medical institutions and can be used once to avoid cross infection.
"Pill-type" internal thermometer
On March 14, 2019, researchers at Tohoku University in Japan newly invented a "tablet-type" internal thermometer that can be excreted with excrement, and has been successfully tested on dogs. This internal thermometer is about 9 mm in diameter and about 7 mm thick. It is only the size of a tablet and contains a temperature sensor and a micro integrated circuit. The exterior is made of resin. It does not use a button battery that is harmful to the human body. Instead, it uses gastric acid contact electrodes to generate electricity and store it in a capacitor. It can measure the body temperature and send data every 30 minutes.