A design of eddy current controller in electron gun using 3D boundary element method

A transient electromagnetic field of the electron gun in a color picture tube is analyzed using the 3D-boundary element method, and the eddy current controller is designed to shield the stray field from the magnetic deflection yoke. The stray field from the deflection yoke, which induces an eddy current on the electron gun and brings about the convergence error on the screen among the red, green and blue beams, is approximated as saw type field and Fourier transformed to be used as an incident field in the analysis. The boundary element formulation is achieved by using the (jw) method. By comparing the shielding effects of the eddy current controller with increasing length of the controller, it is shown that the eddy current controller can be designed optimally.