"UV Light Ultraviolet" is a simulator of ultraviolet Light.  In the app you can change and select the tone of color that you want (Deep purple variations), the time that you want the screen will be active and the brightness of your screen. 

All the colors in "UV Light Ultraviolet" are optimized to show a powerful radiant effect.

"UV Light Ultraviolet" is only for fun and doesn't produce real ultraviolet Light, UV Light Ultraviolet just mimics the color of a UV Light 

Have fun!