Process for fabricating a color cathode ray tube

Claim 1

An improvement in the process for fabricating the basic patterned windowed-web portion of a color cathode ray tube screen structure formed on the interior of a substantially concave glass face panel having a viewing area with an axis therethrough peripherally circumscribed by continuous skirt-like wall terminated by a sealing edge, said wall having a plurality of inwardly projecting mask positioning means spatially oriented therein, said basic patterned structure being an array of multitudinous window openings defined by an interstitial webbing formed on said viewing area by discreetly controlled exposure of the viewing area portion of a negative radiant-energy sensitive coating applied to the interior of said panel including said wall and said mask positioning means oriented therein, said exposure being effected by radiant energy projected from a predeterminately positioned primary emission means discretely directed through the openings of a proximally associated apertured mask member spatially oriented within said panel by said positioning means to provide a latent polymerized image in the coating defining the subsequent pattern windows covering the viewing area, whereupon said mask member is removed from said panel, said process improvement being additional procedures comprising: positioning said panel in a manner to locate an areal internal shielding member within said coated panel at a location substantially intermediate the viewing area and said mask positioning means in a manner to protect the priorly formed latent imagery of the window pattern disposed thereon during subsequent exposure of said panel; orienting at least one secondary emitter of radiant energy relative to said shielding member and the wall of said panel in a location to beam exposure radiation toward said sidewall; exposing only that portion of the radiant energy sensitive coating disposed on the wall of said panel by a flood of radiant energy emanating from said secondary energy emission means in a manner substantially normal to the axis of said panel to provide a defined band of polymerized coating therearound; removing said panel from said shielding member and said secondary emission means; developing sid diversely exposed area of coating on the interior of said panel to remove the unexposed portions thereby providing a pattern of polymerized window areas on said viewing portion and a polymerized band on said wall; overcoating the interior of said panel with an opaque material; and treating the interior of said panel with a degrading agent to loosen and remove therefrom the polymerized material along with the opaque material deposited thereon to provide the interstitially defined windowed webbing of the screen area circumscribed by a substantially bare glass sidewall wherein the mask positioning means are free of coatings.