The illuminant is composed of an infrared light emitting diode matrix. The infrared emitting diode is made of a material with high infrared radiation efficiency (commonly used GaAs GaAs) to form a PN junction, and a forward bias is applied to inject a current into the PN junction to excite infrared light. The spectral power distribution is center wavelength 830 ~ 950nm, half-peak bandwidth about 40nm, it is a narrow band distribution, which is the range that can be felt by ordinary CCD black and white cameras. Its biggest advantage is that it can be completely red-free, (using 940 ~ 950nm wavelength infrared tube) or only weak red storm (red storm is visible red light) 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, but near the maximum rated value of the forward current, the temperature of the device rises due to the heat consumption of the current, causing the light emission power to decrease. If the infrared diode current is too small, it will affect its radiant power. However, if the operating current is too large, it will affect its life and even burn the infrared diode.