摘要:
An electron-optical device comprising a cathode-ray tube having a cylindrical neck of a very small external diameter, particularly ≦ 15 mm, whose inner surface carries a multi-element layer electrode such as a helical structure formed from a high-ohmic resistance material, which structure constitutes a focusing lens. In combination with a deflection system having a correspondingly small diameter, very high scanning frequencies can be realised. Application, inter alia , in projection tubes and electron beam pumped lasers (for example, scanning lasers).