The new crown pneumonia is raging, and the demand for medical and health equipment has also increased. From small forehead thermometers to large ventilators, they are experiencing explosive growth. In recent years, in order to improve the comfort of patients and improve the accuracy of diagnosis, more and more medical and health products have been widely used. Among them, the temperature sensor is an indispensable component of many medical equipment. After all, body temperature is one of the most direct responses of human health. Through the temperature, you can intuitively see whether the patient is infected or hypothermic. As the medical device market has grown, so has temperature sensors. What are the classifications and technologies of medical grade temperature sensors? Let's find out together next!
1. The classification of medical grade temperature sensors
There are several types of medical grade temperature sensors according to their applications, including disposable temperature sensors, temperature sensors for ablation applications, and sensors for forehead thermometers and ear thermometers. Among them, temperature sensors for disposable medical applications mainly use NTC thermistors; ablation applications use thermocouples; forehead thermometers and ear thermometers use thermopile technology.
2. The technology of medical grade temperature sensor
Medical grade temperature sensor NTC thermistor is a heat-sensitive semiconductor resistor, its resistance value decreases with the increase of temperature, the temperature coefficient of resistance is about 10 times the temperature coefficient of metal resistance, the change of resistance value of NTC thermistor can be It is caused by changes in the external ambient temperature, or it can also be caused by self-heating due to the flow of current.
Thermocouples work by joining two dissimilar metals together to form a sensing junction. When the temperature of the sensing junction and the free end are different, the thermocouple will develop a voltage between the two wires. The voltage signal can be converted into a temperature reading. Medical "miniature" thermocouples are thermocouples made with smaller diameter wires, typically 38AWG (0.10mm outer diameter) or smaller in diameter.
Forehead thermometers and ear thermometers use infrared thermometers with thermopile probes to measure the radiation energy emitted by the object. According to Boltzmann's law, the greater the radiation energy, the higher the temperature of the object, and the infrared radiation signal will be measured. Converted into an electrical signal, and then through the amplifier and signal processing circuit, and corrected according to a certain algorithm and target emissivity, it can finally be converted into the temperature value of the measured target. The main component of the one-time temperature sensor temperature measurement is the thermopile, and the thermopile infrared probe is a temperature sensor composed of a series of thermocouples in series, thereby improving the detection sensitivity of the sensor.