An electron gun for a monochrome cathode ray tube to be used in a projection
display
device includes a cathode for emitting thermal electrons, and first and second
electrodes forming a triode portion together with the cathode. A third electrode
is adjacent the second electrode. A fourth electrode is adjacent the third electrode
to receive a focus voltage. A fifth electrode partially surrounds the fourth electrode
while being adjacent the fourth electrode to receive an anode voltage together
with the third electrode. The second electrode has a bottom portion with a stepped
portion surrounding a hole for guiding the electron beams while being protruded
toward the first electrode, and a sidewall portion extended from the periphery
of the bottom portion toward the third electrode. The first and the second electrodes
are structured to satisfy the following condition: 0.54T/G1.50
wherein T(mm) indicates the thickness of the bottom portion of the second electrode,
and G(mm) indicates the distance between the first and the second electrodes.
