IR Illuminator Video surveillance is the direction of development, outdoor, outdoor monitoring the direction of development is night vision, night vision is the direction of development of infrared technology, this trend is more and more obvious.
Light is an electromagnetic wave, IR Illuminator its wavelength range from a few nanometers (1nm10-9m) to 1 mm (mm) or so. The visible wavelength is from 380nm to 780nm, and the wavelength of visible light is from long to short to red, orange, yellow, green, blue, blue, and purple, and the wavelength is shorter than that of purple. Called ultraviolet light, the wavelength is longer than the infrared light called infrared light.
Ordinary CCD black and white camera can feel the spectral characteristics of light, it can not only feel the visible light, and can feel the infrared light. IR Illuminator This is the use of ordinary CCD black and white camera, with infrared light can be more economical to achieve the basic principles of night vision. The spectral characteristics of ordinary color cameras can not feel the infrared light, it can not be used for night vision.
The luminous body is composed of an infrared light emitting diode matrix. Infrared emission diode from the infrared radiation efficiency of high materials (commonly used gallium arsenide GaAs) made PN junction, plus forward bias to the PN junction injection current excitation infrared light. Spectral power distribution for the central wavelength of 830 - 950nm, half-peak bandwidth of about 40nm or so, IR Illuminator it is narrowband distribution, for the ordinary CCD black and white camera can feel the range. Its biggest advantage is that there can be no red storm, (using 940--950nm wavelength infrared tube) or only weak red storm (red storm for visible red) and long life.
The emission power of the infrared light emitting diode is expressed by the irradiance μW / m2. In general, the infrared radiation power is proportional to the positive operating current, but near the maximum current rating of the forward current, the device temperature increases due to the heat consumption of the current, so that the light emission power. Infrared diode current is too small, IR Illuminator will affect the radiation power to play, but the working current is too large will affect its life, and even the infrared diode burned.
When the voltage crosses the forward threshold voltage (about 0.8V or so) the current begins to flow and is a very steep curve, IR Illuminator indicating that its operating current is very sensitive to the operating voltage. So the working voltage is accurate and stable, otherwise it will affect the radiation power and its reliability. The radiated power decreases as the ambient temperature increases (including the ambient temperature generated by its own heat). Infrared light, especially long-distance infrared light, heat consumption is the design and selection should pay attention to the problem.
The maximum radiation intensity of the infrared diode is generally in front of the optical axis and decreases with the increase of the angle between the radiation direction and the optical axis. The angle of 50 which is the maximum of the radiation intensity is called the half intensity radiation angle. The radiation angle of the infrared light emitting diodes of different packaging process models is different.
Thermal radiation phenomenon is very common, the object in the low temperature generated when the heat radiation is all infrared light, so the human eye can not be directly observed. When heated about 500 degrees, will produce dark red visible light, with the temperature rise, IR Illuminator the light becomes brighter and more white. In the heat radiation source by heating the filament to maintain its temperature, for the radiation continue to proceed. Maintain a certain temperature and the energy supplied from the outside is balanced with the energy reduced by radiation.
Radiation at different heating temperature, IR Illuminator the radiation peak wavelength is different, the spectral energy distribution is different.
According to the above principles, the special design and technology made of infrared light bulbs, the infrared light components up to 92 - 95. Foreign production of such infrared light bulb technical performance:
Power 100 - 3.75W; power supply voltage 230--250V; IR Illuminator service life of 5000 hours, radiation angle of 60 - 80 degrees.
Ordinary black and white cameras feel the spectral frequency range is also very wide, and infrared bulbs can generally be made of relatively large power and large irradiation angle, it can be used for long-distance infrared light, which is its biggest advantage. The biggest shortcoming is the inclusion of visible light components, that is, red storms, and short life, if working 10 hours a day, 5000 hours can only use more than a year, consider the heat is not enough, life is shorter.