Research On Deflection Circuit S-Correction In Big Deflection Angles CRTs

In order to compete with the flat panel displays, the cathode ray tubes have to be slim. Being slim leads to high deflection angles. There will be serious raster distortion with large deflection angles in traditional deflection circuits system because of different scanning speeds of electron beam on different parts of screen. Therefore some improvements of the traditional deflection circuits have to be made. This paper is to analyze the line deflection circuit improvements with large deflection angles. At the beginning, the comparison of practical basic s-correction deflection currents and theoretical deflection currents result in a theoretical improving method, which is based on multi-sine current principle. According to feasibilities of real circuits, another voltage modulation improving means is proposed. This means is different from the theoretical one but is easy to operate. After simple principle analysis of this circuits improvement, some important circuit parameters are selected as variables to begin with more detailed simulations and tests. The simulation data are compared with the theoretical ones. The circuit simulation platform is OrCAD/Pspice. This voltage modulation method is proved as feasible after all these simulations and tests. Some PCB circuit tests are performed afterwards. All these tests provide valuable experiences for the next steps of improvements of big deflection angles circuits. At last, this paper describes some possible current modulation improve method and shows some circuit simulation result, which may be reference of circuit improvements in this direction.