The sun is a point light source, it sent out the light of the complex colored light, going through a prism can be decomposed into red, orange, yellow, green, blue, indigo, purple seven monochromatic radiations.

We of the insecticidal light is made from three points of light source, it is respectively 365 nm 450 nm), black, 750 nm yellow, because of their optical path difference can not reach the interference conditions, so this three kinds of light will not interference occurs in closer look, the three kinds of light is three light, will not have an impact. If in the afar, due to the resolution of the limit of the human eye, for example in 2 Km beyond, will find three light source into a point, approximate become point light source, at this time, we can turn the light source as a point light source, then three monochromatic components (approximate monochromatic light) also became a kind of complex colored light. But what is it ?