Measurement results ultraviolet led light and Blue led light
Because ultraviolet light has a shorter wavelength than other led light .so Ultraviolet led light too weak to Glow.If you want to gain that facular concentrated, high brightness, and no stray light, no black hole, no shadow or dark areas. The technology are very difficult. it uses only ordinary Reflection bowl and lens.

we think in terms of more than 4pcs lens solution to the question of ultraviolet led light.