Patent ID: 7449827
Filing Date: 2008-11-11
Classification: H01J

Abstract:
1. An image forming apparatus comprising: an electron source substrate having a plurality of electron-emitting devices and wirings to apply voltages to said electron-emitting devices; an anode substrate which is arranged so as to face said electron source substrate and has light emitting members each of which emits light by irradiation of an electron emitted from each of said electron-emitting devices and an anode electrode; a frame which exists in peripheral portions of said electron source substrate and said anode substrate and forms a vacuum container together with said electron source substrate and said anode substrate; and a spacer which is arranged so as to become into contact with said electron source substrate and said anode substrate and holds a distance between both of said substrates, wherein said spacer has an insulating substrate having concave and convex portions along a normal direction of said electron source substrate and said anode substrate and a high resistance film having a resistance lower than that of said insulating substrate and a rough surface corresponding to the concave and convex portions of said insulating substrate, and a thickness of high resistance film locating on each portion which crosses normal lines of said electron source substrate and said anode substrate among the concave and convex portions of said insulating substrate in at least a partial region of said spacer satisfies the following general equation (1) where, t: thickness of high resistance film (Å) dp: primary electron penetration length (Å) =m×E λ: ionization electron diffusion length (Å) =30/Q E: upper limit value of primary electron energy (keV) m, n, Q: parameter constants which are experimentally obtained from characteristic of incident energy dependency δ(E) of secondary electron emission coefficient and specific gravity of spacer surface by the following general equations (2), (3) and (11) where ρ (g/cm on the basis of the ratio between an effective atomic amount A (Zeff) obtained from the composition ratio of the film and an effective atomic number Zeff, where, P: parameter constant which is experimentally obtained from said δ(E).