Patent ID: 6369499
Filing Date: 2002-04-09
Classification: H01J

Abstract:
A CRT, comprising:a neck; a funnel having an internal reactive coating; a target; and an electron gun in the neck including a triode that forms an electron beam and a focusing lens that focuses the electron beam onto the target, the triode including a cathode having an active area that when heated emits electrons and other byproducts, a suppressor electrode with an aperture that acts as an iris to control the size of the cathode's active area, and an extractor electrode with an aperture for extracting the emitted electrons through the iris to form the electron beam, the suppressor electrode and the extractor electrode each having at least one vent hole adjacent their respective apertures, the vent holes being aligned to provide a line of sight from the cathode through the main lens to expose the funnel so that the byproducts can travel from the cathode through the vent holes along the line of sight to the funnel where they are neutralized by the reactive coating.