The front of the parallel light wave is a plane, and the radius or width of the light beam is always the same, and the energy is concentrated, and the intensity is high when it shines on the eyes. If the energy is too high, it is easy to make people blind!

Divergent light waves are spherical in front, and the radius of the beam expands with the propagation distance, or the width of light is getting bigger and bigger, and the energy is getting more and more dispersed. Irradiated to the eyes, less damage than parallel light, suitable for ordinary lighting!

Converting divergent light into parallel light is to concentrate energy and the beam has good directivity!