Patent ID: 8106575

Claim:
An electron beam apparatus comprising: an insulating member having a recess formed in a surface thereof; a gate disposed on the surface of the insulating member; a cathode disposed on the surface of the insulating member, the cathode being located such that the cathode faces the gate via the recess; and an anode opposed to the cathode via the gate, wherein the recess has a step structure formed on a surface close to an edge where the cathode is located, wherein the step structure is a depression, and wherein an angle θ 1 of a side wall, located closer to an opening of the recess, of the depression with respect to an imaginary plane extending over the depression from the surface of the recess satisfies a condition described below θ 1 >tan −1 (d/W) where d denotes a distance from an edge, on the same side as that where the cathode is located, of the recess to the gate, and W denotes a distance from the edge of the recess to the depression.