| 摘要 |
PURPOSE: An inner shield assembly for a terrestrial magnetic field shielding is provided to restrain a deterioration of purity characteristic, a raster distortion and a variation of convergence characteristic by increasing a strength of diamagnetic flux. CONSTITUTION: An inner shield comprises two or more symmetrically-divided shielding parts(2) to shield an exit of an electron gun from a terrestrial magnetic field. The shielding parts(2) are integrally formed with flanges(6) contacting to a frame body(4). One of the shielding part(2) has extended portions(8), and the other shielding part(2) has coupling holes(10) in which the extended portions(8) are fitted. The shielding parts(2) include saw-teeth parts(12) having a plurality of notches at peripheral surfaces of the incident direction of electron beam. Since the saw-teeth parts(12) increase line areas, the strength of diamagnetic flux applied to the saw-teeth parts(12) is also increased against the terrestrial magnetic field applied from outside, to thereby mitigate an affection of the outer magnetic field.
|
