The technical principle of the infrared camera

Light is an electromagnetic wave with the same nature as radio waves. Generally, infrared light is divided into three parts: near, middle, and far infrared. Near-infrared refers to the wavelength of 0.75~3.0 μ m; middle infrared refers to the wavelength of 3.0~20 microns; Far infrared refers to the wavelength of 20~1000 microns.

According to its infrared radiation mechanism, infrared lamps can be divided into semiconductor solid light emitting and thermal radiation infrared lamps.

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●The technical principle of the infrared camera

The technical principle of the infrared camera

The infrared camera is actually a monitoring device that integrates the monitoring camera, protective cover, infrared light, power supply, heat dissipation unit, etc. The most commonly used infrared waterproof camera in monitoring engineering is active infrared, which is emitted by LED. CCD or CMOS can be used to sense the spectral characteristics of infrared light (that is, visible light and infrared light), and infrared light can be used as the "lighting source" for night vision imaging. The market is dominated by infrared LEDs with emission wavelengths of 850 nm and 940 nm. The early infrared night vision system was not used for civilian use, but mainly for military use. However, because the active infrared night vision system emits infrared, it is easy to be detected by the enemy, so it has been basically eliminated in the military. In the military field, an infrared thermal imager is mainly used. Its camera system can sense the infrared radiation emitted by objects above absolute zero (- 273 ℃). The higher the temperature of the object, the more infrared radiation is emitted and easy to image. Due to the target market and manufacturing costs, few security manufacturers producing civilian cameras produce passive infrared cameras.

An infrared lamp is the core component of an infrared camera. There are two main categories in the market. One is the traditional round LED lamp, which is a relatively traditional and commonly used infrared light source; The other is the "array" infrared camera lamp. The photoelectric conversion rate of the ordinary LED is 10%, while the photoelectric conversion rate of the "array" infrared camera can be increased to more than 25%. At night, it is difficult to distinguish faces from clothes in images. In addition, its calorific value cannot be fixed around the lens of the surveillance camera like the traditional infrared lamp. Most of the "array" infrared cameras seen in the market are separated from the lens, and the infrared lamp is fixed on the upper and lower or left and right sides respectively.

The infrared light source is related to the life and distance of the monitoring camera. Generally speaking, the radiation power of the infrared lamp is directly proportional to the forward working current, but when it is close to the maximum rated value of the forward current, the temperature of the device will rise due to the heat consumption of the current, which will reduce the optical emission power. If the current of the infrared diode is too small, it will affect the exertion of its radiation power, but if the working current is too large, it will affect its life, and even cause the infrared diode to burn out.

The company specializes in producing infrared lenses, night vision objective lenses, and other customized optical lenses for thermal imagers, infrared sights, night vision devices, infrared cameras, and drone monitors.