an optical lens, wherein the image beam emits to the optical lens and a part of the image beam passes through the optical lens to form a first projecting beam, and {HEAD ~ a part} of {TAIL ~ the image beam} is reflected by the optical lens to form a second projecting beam 
an optical lens , wherein the image beam emits to the optical lens and a part of the image beam passes through the optical lens to form a first projecting beam , and { HEAD ~ a part } of { TAIL ~ the image beam } is reflected by the optical lens to form a second projecting beam
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 OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH