Patent ID: 7479730

Claim:
A field emission device, comprising: a rear substrate; a cathode electrode on an upper surface of said rear substrate; at least one group of emitters for emitting electron beams and arranged in a row extending in a first direction on an upper surface of said cathode electrode; a gate electrode placed on said upper surface of said cathode electrode and extending in said first direction for extracting electrons from the emitters, and including first opening portions extending in a second direction perpendicular to said first direction and respectively corresponding to respective ones of the emitters; a first insulating layer interposed between said gate electrode and said cathode electrode; a focus electrode placed on an upper surface of said gate electrode and including a second opening portion extending in said first direction and connected to the first opening portions; a second insulating layer interposed between said focus electrode and said gate electrode; a front substrate disposed a predetermined distance above said rear substrate and having an anode electrode on a lower surface thereof; and a fluorescent pattern formed on a lower surface of said anode electrode for emitting light when electron beams collide with it; wherein a relatively high voltage is applied to the first opening portions and a relatively low voltage is applied to the second opening portion connected to the first opening portions, whereby a quadruple lens structure is formed.