The CMD cameras use a high-performance LED illuminator. As standard these work on the 940nm wavelength making them invisible to the human eye when turned on.
This is important for room occupants as it means they can get undisturbed sleep when the lights of the room are off.
The spread of the IR illumination is matched to the camera lens angle to optimise the coverage of room with camera view and light.
Click here for some gentle reading about infrared