Earlobe-type Electronic Thermometer and NTC Thermistor

Technical Support

Earlobe-type Electronic Thermometer and NTC Thermistor


At present, the usual thermometer on the market are mercury thermometer, electronic thermometer and infrared ear thermometer. Among them, mercury thermometer contains mercury, which is now banned in some countries; Electronic thermometer is cheap, but the measurement time is relatively long, generally takes 1-5 minutes to measure; The measurement time of infrared ear thermometer is relatively short, generally only takes 1-3 seconds to measure body temperature, but the price is more expensive, which is difficult to popularize. The NTC thermistor produced by EXSENSE Electronic Technology Co., Ltd. is widely used in electronic thermometer and plays the role of temperature measurement.

In the thermal conductivity structure design of traditional electronic thermometer, the core component NTC Thermistor is installed in the metal temperature-sensitive head of the electronic thermometer and fixed with glue. The drawback of using glue fixing is that once the glue dries up, it will make the metal temperature-sensitive head and NTC thermistor generate heat insulation effect, resulting in NTC thermistor and the inner wall of metal temperature-sensitive head can’t quickly complete the heat transfer. Once the metal temperature-sensitive head encounters a temperature change, the heat energy can’t be quickly passed on to the NTC thermistor. Therefore, the defects of the thermal conductivity structure of the existing thermometer will lead to a relatively long measurement time. In addition, the measuring positions of existing thermometer are three: armpit, mouth, rectum. Temperature measurement of rectum is not convenient, which is difficult to be widely accepted. Temperature measurement of mouth is neither safe nor hygienic, so which is also difficult to be widely accepted. Temperature measurement of armpit, it’s easy to cause measurement error because the electronic thermometer is not clamped properly.

In order to solve the technical problem above, let’s introduce a kind of earlobe-type electronic thermometer, which has simple structure and can effectively shorten the time of temperature measurement. Moreover, the area behind the earlobe is close to the arteries that carry blood to the brain, which is the best part of the body that measures body temperature in vitro. This electronic thermometer includes power supply, temperature acquisition module, modulus conversion chip, micro controller, LCD display. The power supply is connected to the temperature acquisition module, the modulus conversion chip and the micro controller respectively. The temperature acquisition module comprises a metal temperature-sensitive chip and an NTC thermistor unencapsulated bare chip, and it’s encapsulated on the metal temperature-sensitive chip. This earlobe-type electronic thermometer also includes a voice playback module, which is connected to the power supply and micro controller respectively.

In the earlobe-type electronic thermometer, through the metal temperature-sensitive chip close to the skin to collect body temperature, NTC thermistor unencapsulated bare chip is encapsulated on the metal temperature-sensitive chip, improving the defect of encapsulated thermistor due to the surface insulation paste appears heat insulation. Because the NTC chip is tightly welded on the inner wall of the metal temperature-sensitive chip, it can achieve thermal balance in a short period of time, measure body temperature more quickly, save time and make lower cost. At the same time, the addition of voice playback module, convenient for patients after the measurement is completed, through the micro controller will measure the temperature value output to the horn playback, for the blind patients to provide convenience.