As shown in FIG 2, {HEAD ~ the image beam C} emits to {TAIL ~ the beam splitter} 30 with an incidence angle θ between 0 and 90 degrees , and the preferable incidence angle θ is between 40 degrees and 50 degrees 
emits to
As shown in FIG 2 , { HEAD ~ the image beam C } emits to { TAIL ~ the beam splitter } 30 with an incidence angle θ between 0 and 90 degrees , and the preferable incidence angle θ is between 40 degrees and 50 degrees
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH