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