When the threshold level VREF·1 is set slightly lower than the level V1 of white, a video signal 36 is obtained in which red, {HEAD ~ blue} and {TAIL ~ black} are in the L level state 
When the threshold level VREF·1 is set slightly lower than the level V1 of white , a video signal 36 is obtained in which red , { HEAD ~ blue } and { TAIL ~ black } are in the L level state
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 OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH