IMAGE FORMING DEVICE

PROBLEM TO BE SOLVED: To prevent an electron emitting element from malfunctioning owing to a ringing signal by making the resonance frequency of the ringing signal higher than the maximum value of the frequency that a driving signal has. SOLUTION: Let f0>fmax where f0 is the resonance frequency that a driving circuit including an electron source has and fmax is the maximum frequency that the driving signal has when an image is displayed. Further, the resonance frequency f0 is calculated from the calculation equation consisting of the inductive components Lro and Lco between lead-out parts for row and column wires and the connection part of the driving circuit, an inductive component Lmo between electron discharging elements in a simple matrix, and a capacitive component (Cmo) formed of the wire at an intersection of row and column wires and an inter-layer insulating layer. Further, the inductive components Lro and Lco between the lead-out parts for the row and column wires and the connection part of the driving circuit are