The diffuser plate 4 has the function of emitting {HEAD ~ light source light} diffusingly in {TAIL ~ a predetermined angular range} 
diffusingly in
The diffuser plate 4 has the function of emitting { HEAD ~ light source light } diffusingly in { TAIL ~ a predetermined angular range }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL