wherein an incidence angle of the image beam to the optical lens is between {TAIL ~ 0 degrees} and {HEAD ~ 90 degrees} 
wherein an incidence angle of the image beam to the optical lens is between { TAIL ~ 0 degrees } and { HEAD ~ 90 degrees }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD