Magnetic Field Distribution of Shadow Mask and Its Influence on Electron Trajectory

It is well known that, in a color CRT, color change occurs due to the magnetization of the shadow mask and frame under ambient, e.g., terrestrial, magnetic field. In order to clarify quantitatively the influence of the magnetization of the shadow mask and frame, we measured the magnetic field distribution around the mask and frame, and calculated the change in electron beam trajectory using a slit model to simulate the shadow mask. The results show that remarkable changes in the trajectory and velocity of an electron beam occur in the slit, where the magnetic flux density is high.