Study of a Normal-gate CNT-FED Using HOP Glass

Abstract

Field emission display inherits excellent display qualities of traditional CRT and is a prospective flat display panel. Traditional normal gate FED consists of front and rare glass substrates, using spacer matrix for maintain fixed gap. Compared with diode structure, the modulation voltage is lower in triode structure because of the shorter gap between gate and cathode. However, in a normal gate triode, the field emission emitters can be easily destroyed because of the later fabrication of dielectric layer and gate. Moreover, cathode emission is quite sensitive to structure parameters such as dielectric layer' thickness, anode voltage and gate aperture; therefore, it is hard to guarantee emission uniformity. This paper introduces a structure similar to HOP one to solve the problems above. Gates and sequent spacers are screen printed on glass. Because the field emitters and hop glass are fabricated respectively, the emission emitters will not be destroyed in the later process the vacuum gap between cathode and gate replaces dielectric layer, so the small modulation voltage can be obtained. To ensure the mechanical strength of the hop glass plate, the thickness of the hop plate increases to 0.55 mm. Because glass is flatter than ordinary dielectric layer, better emission uniformity can be gotten. The hole of the hop plate is similar to dumbbell structure. We can change the shape of the hole to get good display effect. At present, the number of electrons reaching anode is less than 1% of electrons emitted by carbon nanotube. Thereupon, we should evaporate MgO to the lower half part of the holes to get secondary electrons. Now the voltage of gate is about 250 V. The technique flow shows as follows. At first, the CNTs paste was printed on cathode and the phosphors paste was printed on anode by screen-printing method and fired at 160degC. Then, the holes of hop plate are eroded by chemical method. The gate preparation is also use screen-printing method. And MgO is evaporated. Next, cathode plate, anode plate and gate plate are packaged by frit. At last, after pumping, we get the display panel