| 摘要 |
PURPOSE:To improve the electron beam permeability of a shadow mask by constructing the electron beam pass hole of a shadow mask to have the function of bypotential type tubular lens for focusing the electron beam onto a phosphor material layer. CONSTITUTION:An insulator 273 is placed between two shadow mask members 271, 272 in a shadow mask 27 then different potentials are applied between said members 271, 272 and the function of bypotential lens type tubular lens having the potential ratio within 1.1-1.3 is provided to each electron beam pass hole 29. Consequently the electron beam 33 is focused when passing through the hole 29 and the width of the electron beam impinged on a phosphor face 19 is focused from width (A) to (B). Consequently the permeability of the electron beam 33 of the shadow mask 27 is improved resulting in the improvement of the brightness of the screen. |
