Study of Electron Beam Trajectory within CRTs Containing U-Shaped Magnetic Sheets

This paper proposes a new method for shielding the ambient magnetic field in a CRT. The key to the method is the use of U-shaped magnetic sheets arranged around the frame of the CRT. The sheets are magnetized by the ambient field, and create a demagnetizing field to cancel the field perpendicular to the screen. They are thus an effective means of reducing mislanding. For example, mislandings at the corner of the screen were reduced to one-fourth of the number that occurred without the sheets. On the other hand, the sheets have no shielding effect on the field parallel to the screen.