A finite difference method in non-orthogonal curvilinear coordinate is used for the simulation of two dimensional electrostatic field. The computational formula is derived. Several electrostatic problems are calculated. The results show that numerical meshes fit the complex boundary well and higher accuracy can be got by less numerical discrete cells.

In color monitor tubes, electron optical system influences the quality of the whole tube directly. In the wake of development of HDTV and graphic display in workstation, the quality of color monitor (display) tubes must be improved. For achieving display with high resolution, an axiasymmetric electron optical system is adopted to decrease the size of spot on screen. This paper uses SEU-3D program to simulate electron optical system in color monitor tubes. Taking account of the characters of electron optical system in color monitor tubes, this program uses some special methods to analyse the system so that the result obtained from the simulation can fit the actual condition properly.

Since the structure of deflection system is complicated, FEM (Finite Element Method) may be suitable to calculate the system. However, the deflection field has no definite boundary, it must be taken as an open boundary problem. In view of some peculiarities of deflection system, an improved method FEM-BEM is proposed for analysis. This method is different from ordinary hybrid method, it not only improves the accuracy of deflection traces, but also decreases the requirement for computer speed and memory.

In electron optical system, electron beams emitted by cathode will be focused and deflected by electron optical system, and then it will hit the screen with small size. Because deflection system has deflection aberration, the electron beam that is focused into one point in the centre of screen will not be focused well in the corner of screen, and it will become a circle spot. Because decison of the spot quality on the screen is ac, this paper described the hay research for electron optical syStem quality.The spot size on screen is changed with the changing of screen location, so the' electron optical system quality is receded fuzzily when screen location is changed. According to these fuzzy decisions, a best structure of electron optical system can be founded.

There are two methods to calculate the triode system of electron gun:First method is Continuous Emitting method, it regards the cathode emitting as a continuous action, so it can only calculate a few of electron trajectories, and takes short time. Because it calculates a continuous cathode emitting, the error of calculation is big. The second method is Monte Carlo method, it calculates the cathode emitting with random method, and then calculates many random electron trajectories. The error of this method is smaller than Continuous Emitting method, but it will take a lot of time. This paper discusses a new method, it regards the cathode emitting as a continuous action when the value of electric field is not very precise, then it uses Monte Carlo method to calculate triode system when the value of electric field is precise. This new method decreases the error of calculation and saves time of computation.