Cathod-ray tube

Abstract

A cathode ray tube comprising an electron source and an electron beam guidance cavity having an input aperture and an output aperture, wherein at least a part of the wall of the electron beam guidance cavity near the output aperture comprises an isolating material having a secondary emission coefficient δ1 for cooperation with the cathode and for forming an electron source. Furthermore, the cathode ray tube comprises a first electrode which is connectable to a first voltage source for applying, in operation, an electric field with a first field strength E1 between the cathode and the output aperture. δ1 and E1 have values, which allow electron transport through the electron beam guidance cavity. According to the invention, the cathode structure comprises means for reducing the spread of the energy distribution of the electrons leaving the exit aperture between the input of the cavity and the accelerating grid.

Dependencies are inferred from the claim text.