The global magnetic force distribution of single moving electron is firstly obtained by means of spherical cap harmonic analysis.In order to reduce the geomagnetic effect on the color picture tube and improve the image quality of the color picture tube

a kind of equipment that can practicably and effectively shield geomagnetic field is put forward in this paper.A new scheme that combines this new equipment with oscillation-method is put forward to more effectively improve the shielding efficiency also.Besides

comparing the shielding result of this new equipment with that of the current shielding style

it is shown that the new equipment is effective and practicable.The geomagnetic tolerance of the color picture tube can be loosened to a large degree after this equipment is used.The achievement in this paper can be applied to the manufacture of the color picture tube.Moreover

it has the practical value to reduce the production cost and increase the benefit.