| 摘要 |
PURPOSE:To secure such an electrostatic focusing type camera tube that is able to turn a beam diameter limiting aperture into a diametral miniaturized type without making cathode load too much as well as to render a beam emanative angle relatively small, through which high resolution can be secured even in the peripheral part of a target electrode surface. CONSTITUTION:When a G2 electrode 9 as the accelerating electrode of a camera tube is impressed with a voltage of 300V and an auxiliary electrode 11 with 1,600V respectively, a focusing type electron lens is formed up between the G2 electrode 9 and the auxiliary electrode 11 whereby each electron beam radiated out of a cathode 1 proceeds through convergent courses shown typically in fine lines 1a, 1b, 1c and 1d, and current density of the electron beam passing through a beam diameter limiting aperture 9a relatively grows large. In addition, a mutual interval between the G2 electrode 9 and the auxiliary electrode 11 and the diameter of the beam diameter limiting aperture 9a, etc., are set to a proper value each whereby diametral miniaturization of the electron beam and the promotion of a narrow beam emanative angle can be all secured. |
