The reflection board can be located adjacent and extend along {HEAD ~ the one flat surface} of {TAIL ~ the light guide} 
The reflection board can be located adjacent and extend along { HEAD ~ the one flat surface } of { TAIL ~ the light guide }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL