wherein the light emitted from {TAIL ~ the secondary light source} is prevented from entering {HEAD ~ the light emitting plate} 
wherein the light emitted from { TAIL ~ the secondary light source } is prevented from entering { HEAD ~ the light emitting plate }
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD