Thus, {HEAD ~ a signal} proportional to the total amount of light received by the photo detecting elements 6a and {TAIL ~ 6b} is supplied to the light intensity control circuit D 
Thus , { HEAD ~ a signal } proportional to the total amount of light received by the photo detecting elements 6a and { TAIL ~ 6b } is supplied to the light intensity control circuit D
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH