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