| 摘要 |
A television camera tube comprising an evacuated envelope enclosing an electron gun. The electron gun has, in the direction of propagation of the generated electron beam, a cathode, a grid, an anode and a cylindrical electrode. The cylindrical electrode has a diaphragm. The anode has a portion that extends substantially perpendicularly to the electron beam and includes an aperture. A first metal foil is provided on the side of the anode toward the target. The metal foil covers the aperture of the anode, but has an aperture for the electron beam. The diameter of the aperture in the foil is no more than 0.15 mm and no less than the diameter of the electron beam. A second metal foil is provided on the anode on the other side thereof. The second foil also covers the aperture of the anode. The second foil has an aperture for the electron beam. The diameter of the aperture in the second foil is smaller than the diameter of the aperture in the first metal foil, but is not less than the diameter of the electron beam. As a result, interference in the recorded image as a result of a return beam in the tube is considerably reduced. |
