Thermal decomposition of infrared sensorsRationaleAnd characteristics
Thermal infrared sensors are widely used in the fields of electronic automatic doors, piracy protection and human detectors, and are popular with a wide range of users because of their low cost and stable technical quality。
Activation and properties of thermal decomposition infrared sensors:
The body temperature is typically 37 degrees, with infrared wavelengths of about 10 m, and the infrared probes work by detecting human-launched infrared sources of about 10 m. The human-launched infrared light around 10 m will be enhanced through the finner filter, which will then gather on the infrared sensor. Infrared sensors are usually thermally ejected elements, which lose the charge balance when the temperature of the human wavelength infrared radiation changes, discharge the charge outward, and generate warning signals after circuit detection。
(1) infrared probes are targeted to detect human wavelengths. So thermal discharge must be very sensitive to infrared radiation with a wavelength of about 10 m。
(2) in order to be sensitive to infrared radiation, it is common for its radiation exposure to be covered by special fennel lenses, which clearly control outside interference。
(3) thermal emission infrared sensors, which contain two interlocking or combined heat emission electrons. The opposite direction of two electrodes is that the external radiation is almost identical to the two thermal components, resulting in the offsetting effect of the discharge, so that the sensor has no signal output。
(4) once a person enters the detection area, the human wavelength radiation is focused through a partial lens and received by thermally deciphered electrons, but the heat received by the two heat-emitting electrons is different and cannot be offset and alerted by signal processing。
(5) the finella lens requires different performances, with different focal lengths (sensitization distance) and different monitoring and viewing sites, with more scenes and tighter controls。
Advantages and disadvantages of passive thermal discharge infrared probes:
Advantages:
There is no radiation of any kind per se, and it's very small and it's very hidden. It's cheap。
Disadvantages:
It's prone to heat and light
Passive infrared penetration is poor, and human infrared radiation is easily overshadowed and not easily received by detection。
Vulnerability to radiofrequency radiation。
When ambient and human temperatures are approaching, detection and sensitivity decrease significantly, sometimes resulting in short-term failure。
Interference resistance:
1. Protection against small animal interference: the detector is installed at a recommended altitude and does not generally generate alarms for ground and ground small animals within the detection range。
2. Anti-electromagnetic interference: the detector's anti-electromagnetic wave interference performance meets the requirements of 4. 6. 1 in gb10408 and general cell phone electromagnetic interference does not give rise to misstatement。
3. Anti-light interference: the detector is exposed to h4 halogen lamps three metres away through the glass within normal sensitivity and does not generate alarms。
Installation requirements for infrared thermal discharge sensors:
Infrared thermal emitting human sensors can only be installed indoors, with a high rate of error associated with the location and manner of the installation, and the correct installation shall meet the following conditions:
1. Infrared thermal discharge sensors shall be 2. 0-2. 2 metres from the ground。
Infrared thermal emission sensors are far from air conditioning, refrigerators, furnaces, etc., where air temperature changes are sensitive。
3. Infrared thermal decomposition sensors shall not be separated from screens, furniture, large basins or other separators。
4. Infrared thermal decomposition sensors should not be directed directly to windows, otherwise thermal flow disturbances outside the windows and movement of people could lead to misreporting, and it would be preferable to close the curtains with the conditions. Infrared thermal emission sensors are also not installed where there are strong air currents。
Infrared thermal emission sensors are also highly sensitive to the direction of human movement. Thermal decomposition infrared sensors are the least sensitive to routing reactions, and the most sensitive to transverse direction (i. E., vertically with the radius) movements. Selecting the right location on the spot is an essential link to avoid infrared detection and to optimize detection sensitivity。
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