Abstract：Trilemma effect is an important criteria for the self-convergence deflection system. The influence of the higher order Trilemma effects should be taken into account for the correction of the higher-order deflection aberrations. In this paper, up to the seventh-order Trilemma effects are analyzed with region-cutting by means of the correction theory of the multipole field deflection aberration. The expressions of the various order of Trilemma constant are given, in which the seventh-order Trilemma constant can be used as a criteria of the deflection aberration correction at large deflection angle
1997, Vol. 19 
