In a cathode ray tube having a luminescent screen (fluorescent screen) which has a layer (P) of luminescent material which is scanned by at least one electron beam (E), for the purpose of protection when the electron beam is no longer deflected the luminescent screen is provided with a layer (S) which is of low resistance in the case of temperatures which do not lead to a destruction of the layer of luminescent material and in the case of higher temperatures is of very high resistance or insulating. <IMAGE>
