The improvement 1, wherein said adjusting means further comprises a light shielding member restricting the amount of {TAIL ~ light} leaving {HEAD ~ said main reflecting means} 
The improvement 1 , wherein said adjusting means further comprises a light shielding member restricting the amount of { TAIL ~ light } leaving { HEAD ~ said main reflecting means }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD