◤Intelligent infrared ear thermometer is a kind of non-contact temperature measurement

 

      Common thermometers are mercury thermometers, contact electronic thermometers, forehead thermometers, and ear thermometers. In fact, the mercury thermometer is the most accurate, but the flaws are also obvious, and it takes several minutes to get the measurement results; contact electronic thermometers generally use NTC as a temperature sensor, the measurement speed is faster, but the accuracy is also worse than the mercury thermometer ; Forehead gun and ear thermometer are non-contact temperature measurement equipment. It detects the change in the intensity of infrared radiation radiated from human skin to obtain the temperature. Because the skin inside the ear is less affected by the external environment than the forehead, the ear thermometer will More accurate than the thermostat.

 

 

      Infrared ear thermometers in the United States have been studying the eardrum temperature as the core temperature standard since the mid-1960s. In recent years, a series of infrared radiation ear thermometers have been developed with the United States as the center. This is a thermometer specifically used to measure the temperature of the eardrum. The infrared radiation energy mainly emitted by the eardrum is transmitted to the thermopile through an infrared waveguide. The thermal detector converts infrared radiation energy into electrical energy and performs electrical signal processing to obtain human temperature information. In 1986, T. Shinozaki and others used earphone thermometers for the first time to make ear thermometers that appeared on the US market.

 

◤Infrared temperature measurement principle
 

      Maybe you do n’t know. As long as its temperature is higher than -273 ℃ (absolute zero), it will radiate heat in the form of infrared rays. However, when different objects are at different temperatures, the radiant energy is Different, in fact, infrared rays are also electromagnetic waves. If we can find a way to detect these infrared electromagnetic wave energy and convert it into an electrical signal, then we can get the corresponding temperature after amplification, calculation and compensation.

Because different objects have different infrared emissivity, the infrared electromagnetic wave energy emitted will also be affected by the state of the object, reflectance, and surface state. Therefore, corresponding algorithm calculations and compensations must be made for different measurement targets. The skin is measured on the forehead, and the ear thermometer is measured on the skin of the ear hole.

      Because the skin on the forehead is in contact with the external environment, especially the outdoor environment has a greater impact. Although the ear thermometer's measurement is more accurate, it needs to be plugged into the ear hole when measuring. It is only suitable for family use, not suitable for public use, and younger children will have some resistance.

Dove
2020-4-4

 

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