In this paper, the coma of the fifth-order aberration at a large deflection angle has been analyzed by using multipole field theory. The dilemma effect exists in the comas of fifth-order aberration. The dilemma effect, whose value D3 is constant and independent of the 10-pole field, is the linear combination of coma aberrations. The coma of the fifth-order aberration is corrected by adjusting the 10-pole field distribution when Dr is zero or small. The factors that influence the dilemma effect have been calculated and analyzed.

The carbon nanotube has good field emission properties, so it has been used as the electron source on the field emission display panel. To obtain a high emission current, the electric field at the tip of the nanotube must be large enough. This article studies the variation of electric field with different types of nanotubes. The emission current of the nanotube is also calculated for various geometrical parameters of nanotubes. From the simulation results, the influence of the geometrical parameters on the emission performance of nanotubes is studied.

The fabrication of carbon nanotube emitters with excellent emission properties is described. The multi-walled carbon nanotubes (MWNTs) produced by chemical vapor deposition (CVD) method were purified with oxidation method and mixed with organic binding pastes and then screen-printed on glass substrates with ITO film. We applied anode voltage gradually to refine the emission behavior of the emitter by cleaning the top surface of screen-printed carbon nanotubes (CNTs). The density of the carbon nanotubes is about 2:5 108/cm2. Diode field emission experiments were performed in dynamic vacuum system to study the emission current, the emission uniformity, etc. Bright and stable character emission images were obtained in the diode structure and the emission current could approach 1 mA/cm2.

In the normal gate CNT-FED, the gate electrode is used to modulate and address the electron beam. Some electrons may bombard on the gate electrode, thus the luminant efficiency of CNT-FED decreases. This paper proposes a new gate structure, which is the metal mesh with cone funnels. MgO film and MgF2 film are vaporized on the surface of the mesh and the funnels. When the primary electrons bombard on the gate electrode with initial energy, the secondary electrons and backscatters are generated. As results, more electrons can pass through the gate electrode and land on the anode. Consequently, the brightness of the novel triode structure CNT-FED can increase obviously. In the paper, we show the results of numerical simulation of the secondary electron emission process with Monte Carlo method. Some CNT-FED devices with the new type of gate structure are fabricated. The surface of the gate electrode is coated with MgO, MgF2 and SiO2 film, respectively. The results of emission experiments are also shown in this paper.

In the application of field emitter arrays, it is useful to understand its emission performance. This paper calculates the electric field of a diode emitter array in three-dimensional space. From this calculation, the emission uniformity of a diode array is studied. The dependance of the tip-to-tip spacing and of the cathode-anode distance on the uniformity of the array is also analyzed. The pressure sensor based on the diode model is simulated. From the dependence of the emission current for different tip densities, the influence of the emission uniformity can be obtained. (1999 Published by Elsevier Science B.V. All rights reserved.