{HEAD ~ a light entering region} on the beam directing member whereby the incoherent light beam is directed between {TAIL ~ the two surfaces} 
{ HEAD ~ a light entering region } on the beam directing member whereby the incoherent light beam is directed between { TAIL ~ the two surfaces }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL