{HEAD ~ The other part} of the incident beam is refracted and transmitted through the optical member and then totally reflected by {TAIL ~ the reflecting member} to return to the optical member 
is totally reflected by
{ HEAD ~ The other part } of the incident beam is refracted and transmitted through the optical member and then totally reflected by { TAIL ~ the reflecting member } to return to the optical member
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH