Structure Characteristics and Principle Analysis of Infrared Thermometers
The infrared rays received from the object to be measured are focused on the detector through the lens and the filter. The detector generates a current or voltage signal proportional to the temperature through the integration of the radiation density of the measured object. In the connected electrical components, the temperature signal is linearized, the emissivity area is corrected, and converted into a standard output signal.
In principle, there are two types of portable thermometers and fixed thermometers. Therefore, when choosing a suitable infrared thermometer for different measurement points, the following characteristics will be main:
1. Sight
The sight has this function. The measuring block or measuring point pointed by the thermometer can be seen. The sight can often be used without the sight when measuring a large area. For small objects and long measurement distances, a sight in the form of a light-transmitting lens with a dashboard scale or a laser pointing point is recommended.
2. Lens
The lens determines the measured point of the thermometer. For large-area objects, a thermometer with a fixed focal length is generally sufficient. But when the measurement distance is far away from the focus point, the image at the edge of the measurement point will be unclear. For this purpose, it is better to use a zoom lens. Within the given zoom range, the thermometer can adjust the measurement distance. The latest thermometers have replaceable lenses with zoom. The near lens and far lens can be replaced without calibration recheck. .
3. Sensor, namely spectrum receiver
Temperature is inversely proportional to wavelength. At low object temperatures, sensors sensitive to the long-wave spectral region (hot film sensors or pyroelectric sensors) are suitable. At high temperatures, sensors sensitive to short wavelengths composed of germanium, silicon, indium-gallium, etc. will be used. Photoelectric Sensors.
