Light is an electromagnetic wave, its wavelength range from a few nanometers (1nm = 10-9m) to 1 mm (mm) or so. The visible wavelength is from 380nm to 780nm, the wavelength of visible light from long to short into red, orange, yellow, green, blue, blue, purple, the wavelength is shorter than the purple light. IR Illuminator 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. 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. IR Illuminator 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 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 forward operating current, IR Illuminator 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 play, but the working current is too large will affect its life, and even the infrared diode burned.
When the voltage across the forward threshold voltage (about 0.8V or so) the current began to flow, and is a very steep curve, indicating that the operating current is very sensitive to the operating voltage. So the working voltage is accurate and stable, IR Illuminator 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, IR Illuminator 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. IR Illuminator The angle of 50% of the maximum intensity of the radiation is called the half intensity radiation angle. The radiation angle of the infrared light emitting diodes of different packaging process models is different.