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