FIG 4 is {TAIL ~ a cross sectional view} of an electron gun unit of {HEAD ~ the third embodiment} 
FIG 4 is { TAIL ~ a cross sectional view } of an electron gun unit of { HEAD ~ the third embodiment }
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD