Television picture tube with cathode coating erosion suppression

摘要

This disclosure depicts a novel electron gun having at least one cathode having an electron emissive coating, a forward element and a plurality of electrodes interspaced between the cathode and the forward element. The electrodes and forward element each have at least one aperture wherein the apertures in the electrodes and forward element are coaxial and define at least one beam passageway for passing through the gun a stream of electrons emitted by the cathode during operation. The beam passageway unavoidably forms a conduit for high velocity gas when the gun is located in a narrow neck of a television picture tube and the tube is evacuated of gas through a tubulator located at the rear end of the neck. The improvements in the electron gun comprise a gas influencing element for reducing and perturbing the high velocity gas flow in the conduit at least in the region of the cathode as the tube is evacuated to suppress erosion of the cathode coating by preventing a violent flow of gas over the cathode.