Patent ID: 8368296

Claim:
An electron emission apparatus comprising: an insulating substrate; and at least one grid located on the insulating substrate, the at least one grid comprising: a first electrode, a second electrode, a third electrode, and a fourth electrode located on a periphery of the at least one grid, wherein the first and second electrodes are parallel to each other, and the third and fourth electrodes are parallel to each other; and an electron emission unit, the electron emission unit comprising at least one linear shaped electron emitter, the at least one linear shaped electron emitter comprising: a first end electrically connected with the first electrode, and a second end electrically connected with the third electrode; and two electron emission ends defining a gap located between the first end and the second end, wherein the at least one linear shaped electron emitter is a carbon nanotube wire, the carbon nanotube wire comprises a plurality of carbon nanotube segments joined along a longitudinal axis of the carbon nanotube wire by van der Waals attractive force, each of the plurality of carbon nanotube segments comprises a plurality of carbon nanotubes substantially parallel with each other and combined with each other by van der Waals attractive force therebetween, each of the two electron emission ends comprises a plurality of cone shaped electron emission tips, each of the plurality of cone shaped electron emission tips comprises at least one of the plurality of carbon nanotube segments.