gestione della luce

16:46 May 2, 2014 

- more or less - that the shape, material, finish and so forth of the fixture is somehow used to control the light emitted by the lamp - be it by differential directional shading, diffusion, reflective surfaces or whatever. The usual function of most lightng equipment, in short, but said with a "nicer" marketing spin.
I'm not a native speaker, but you might simply say something like "light control" (or "management", maybe).

16:08 May 2, 2014 

I wouldn't count on it, though - it was just an educated guess. It would be nice to have a picture to confirm it.

15:57 May 2, 2014 

Yeah, that's along the lines I was thinking. Why would they write it that way??? Arrgh! Oh well. If our job wasn't hard it wouldn't be called "work", right? ;) Thanks Phil!

15:35 May 2, 2014 

Maybe it's a roundabout way of saying lampshade or diffuser.