Simulation Of Self-Focusing Electron Emitter

Display technique is one of the most important techniques to transform the vast information to visual. With the rapid development of electronic production and portable mobile communication, we need superior display device with higher information content. The development trend of display devices is digitization and plate. Field emission displays(FED) technology is the very important panel display technology which can keep the display quality as cathode ray tube(CRT) display. And FED has been given great emphases for a long time.The cathode structure is one of the key technology of the FED, but the field emission cathode structure has not yet reached a consensus of opinion so far. The dispersion of electron beam and complexity of fabricate technics are remarkable disadvantages for most of the active structure of the cathode, which leads to the FED very difficult for utility. In this paper, a self-focusing field electron emitter was proposed, The field electron emitter proposed is similar to the SCE films emitter, but the electrodes of gate and cathode are exchanged their playing roles, the gate electrode is placed on center and surrounded by cathode. The simulated results show an significant decrease of the dispersion of electron beam. Because the structure of cathode is very simple, so the fabricate technics is very easy.The distribution of the electric field and the electron trajectory of the emitter were calculated by finite element method, and the influences of the structure parameters on electron focusing were systematically investigated in this paper. The simulated results showed that the self-focusing performance of electron beam became better when the distance of the grid—cathode increased or the width of the grid decreased. The performance was also closely related to the anode voltage and grid voltage, there was an optimum point of the self-focusing performance depended on the anode and grid voltage.In this paper, we also systematically investigate the influences of the sunken grid on electron focusing. The simulated results showed that when grid voltage become larger and larger the self-focusing performance of electron beam and the emission efficiency of the sunken grid and the flat grid became worse, the difference of performance of electron beam between the sunken grid and flat grid become smaller ,but difference of emission efficiency between the sunken grid and flat grid become larger; when grid width become larger and larger, the self-focusing performance of electron beam of the sunken grid and the flat grid became better and difference of performance of electron beam between the sunken grid and flat grid become smaller, the emission efficiency of the sunken grid become larger; the grid width almost have no influences on the emission efficiency of the flat grid; the deepness of the sunken grid have no influences on the self-focusing performance of electron beam and the emission efficiency.