I have an application with LED and It requires a bigger beam . I could obtain a bigger beam by incresing the distance between LED and surface. But îs there the possibility to decrease the energy delivered ??? Photo attached.
Ignoring the effects of contamination in the medium between the emitter and the receptor, the energy received when the receptor is up-close to the emitter will be the same as the energy received when the receptor is at a greater distance. This of course assumes that the receptor has a big enough surface area to receive the "spread-out" light.
What goes down is the received energy per square metre (as the distance is increased) but, nevertheless, the same total energy will hit the receptor because as the energy per metre thins-out, it illuminates a bigger surface area hence, energy is the same.
Assuming that you're shining the LED beam through some non-dispersive, non-absorbtive medium (clean air or vacuum, etc.) then the total energy impinging on the surface won't change.
This is basic physics -- the light energy coming out of the LED continues being light, unless it smacks into something that absorbs it, and it goes in a straight line, unless it smacks into something that disperses it.