Patent ID: 7189979

Claim:
An electron gun comprising: a cathode portion which emits electrons; an anode portion which has an aperture and accelerates the emission electrons; a bias portion which is arranged between said cathode portion and said anode portion and controls trajectories of the emission electrons so as to form a crossover between the bias portion and the anode portion so that the electrons do not strike the anode portion; and a shielding portion disposed below said anode portion for shielding some of the emission electrons and having a cooling portion which cools said shielding portion, said cooling portion being disposed at the lower part of the shielding portion, wherein said shielding portion includes a tilt portion tilting with respect to an incident direction of the emission electrons and includes a closing portion located between the tilt portion and the anode portion for inhibiting the electrons reflected by the tilt portion from passing through the aperture of the anode portion.