Field emission devices having corrugated support pillars with discontinuous conductive coating
View Patent ↗In accordance with the invention, a field emission device is made by providing the device electrodes, forming a plurality of corrugated insulating rods with discontinuous coatings of conductive or semiconductive material with low secondary electron emission coefficient, adhering the rods to an electrode, cutting the rods to define corrugated pillars, and finishing the device. The result is low cost production of a field emission device having superior resistance to breakdown in high field operation.
1. In an electron field emission device comprising an emitter cathode, an anode and a plurality of insulating pillars separating said cathode and anode, the improvement wherein:
at least one said pillar comprises a corrugated rod of insulating material, said corrugations comprising ridges and recessed regions, and said ridges of said corrugations are selectively coated with conductive material having a secondary electron emission coefficient in the range 0.9-1.4 and the recessed regions are not coated with said conductive material.
2. The device of claim 1 wherein said conductive material comprises a material selected from the group consisting of Cu, Co, Ni, Ti, Au, Cu 2 O and Ag 2 O.
3. The device of claim 1 wherein said conductive material has a thickness in the range 0.005-50 μm.
4. The device of claim 1 wherein said conductive material has a thickness in the range 0.1-2.0 μm.
5. The device of claim 1 wherein said pillar has a diameter in the range 50-1000 μm.
6. The device of claim 1 wherein said pillar has a diameter in the range 100-300 μm.
7. The device of claim 1 wherein said pillar has a height-to-diameter aspect ratio of 1:10.
8. The device of claim 1 wherein said pillar has a height-to-diameter aspect ratio of 2:5.