Common problems of infrared monitoring system
Today, everyone's security awareness has increased Security monitoring As far as it is concerned, real-time monitoring in the daytime can no longer meet people's needs, so infrared video camera This part, including the infrared night low illumination camera, is widely used, which is a trend. This article will talk about the common problems of infrared monitoring system:
Red Storm Problem:
Some manufacturers propagandize whether they can produce an infrared lamp without a red storm as a technical problem. It seems that the presence of a red storm is a low technology, and the absence of a red storm is a high technology. In fact, the presence of a red storm is just a matter of choice, not a technical problem. Light with a wavelength of more than 700nm is called an infrared line. Infrared light with a wavelength of more than 900nm is basically free of red storms. The shorter the wavelength, the stronger the red storm, The infrared sensitivity is also higher. Now there are two mainstream infrared lamps on the market, one with a slight red storm at about 850nm, and the other without a red storm at about 940nm. The sensitivity of the same camera at 850nm is 10 times better than that at 940nm. So the infrared lamp with a slight red storm at 850nm has high efficiency, It should be used as an option for infrared night vision monitoring.
Life problems:
The service life of the camera can reach more than 10 years. Can the service life of the infrared lamp also reach this level? To answer this question correctly, first of all, we need to understand the current manufacturing principle of infrared lamps. At present, infrared lamps have three main manufacturing modes: 1. halogen lamps, 2. multi chip led, 3. single chip led. Halogen lamps are a more traditional technology, with high energy consumption, large heat generation, and short service life. It is estimated that they will gradually fade out of the market due to their low use efficiency.
Multi chip led also has two forms, one is composed of four to eight chips; The other is array type light-emitting chips, which contain 10 to 30 chips. Why do you have more chips? Some theories from the manufacturers are that the insufficient irradiation distance of the infrared lamp is due to insufficient energy. Many chips * * * * together, of course, the energy is large. It is taken for granted that the irradiation distance is far. Of course, a long distance requires large energy, but it is not that the camera can receive as much infrared light as the infrared lamp emits.
Multi chip LED has no light-emitting focus due to its inherent structural shortcomings, unreasonable light-emitting optical system, and low useful light efficiency (of course, it is several times stronger than halogen lamp), and its advantages have not been brought into play. For example, array LED, whose current is more than 1000 ma, is basically the size of a penny, and heat dissipation becomes a problem. LED is afraid of high heat, but it is not bad. At the same time, The production requirements of multi chip LED are very strict. Each chip can not have a little difference in performance. Otherwise, if one chip breaks down, the whole machine will be finished. In general, compared with single chip LED, the life of multi chip LED is far from enough.
The production process of single chip LED is simple, the quality is easy to guarantee, the calorific value is low, and the luminous optical system is reasonable. It is an ideal device for making infrared lamps. Theoretically, the service life can reach more than 100000 hours. So, do all single chip LED lamps have good service life?
In fact, this is far from the case. There are many reasons for this. For example, some LED chips are of low level and have excessive impurities; Some production processes are not up to standard and there is leakage phenomenon; Some are used for overpower, rated at 20ma, but use more than 50ma; Some have no protection circuit, or the circuit design is unreasonable, which will lead to the rapid failure of single chip led infrared lamp.
In order to ensure the life of infrared lamps, we must first select high-level LED chips. High level chips have high power, good consistency, high luminous efficiency, and low heat output. A high-level LED is 10 times better than ordinary LEDs in quality, and of course, its price is also very expensive. Secondly, the optical system should be designed reasonably, the light emission should be uniform, the utilization rate should be high, and the heat dissipation should be fast. Third, The operating voltage should be strictly controlled. The led is very sensitive to voltage, and the led core will burn off if the voltage is slightly higher; If the voltage is slightly lower, the luminous amount will be greatly reduced. It is good to match high-quality switching power supply, and the AC input voltage can be well stabilized from 170 V to 270 V, so as to adapt to the harsh power supply environment. Fourth, the input power line is good to choose high/low temperature resistant, ultra soft and bending resistant. There is an infrared lamp produced by a manufacturer, and the input power line can be 60 degrees below zero The product is reliable only when the temperature is 250 degrees above zero and the cable is still as soft as silk when the temperature is 40 or 50 degrees below zero.
