Abstract: A sealing glass composition comprises a PbO-containing glass frit, two particulate refractory fillers having controlled particle size distributions, and optionally at least one additive to prevent the chemical reduction of the PbO when the frit is fired in the presence of reducing conditions. The sealing glass composition is useful as a package sealant. It is especially useful as a solder glass for sealing a face plate portion to a funnel portion of a color television picture tube at temperatures of about 400.degree. C. A particulate glass composition for use in preparing the sealing glass composition, a sealing glass paste and methods of using the sealing glass and paste are provided.

Abstract: A rimless faceplate is mounted on a shadow mask color selection device for a color television tube construction by indexing means establishing a unique positional relationship between the faceplate and the mask. An array of cavities on the inner surface of the plate interfit with the studs on mask mounting brackets to provide transverse positioning while the bracket surfaces extending outward from the studs provide abutting surfaces to the inner face of the faceplate adjacent its stud receiving cavities to establish faceplate-mask spacing. A glass funnel receives the mask in its divergent end with precise spacing of the mask from its seal edge. Portions of the mask mounting brackets are fitted into seats in the funnel which may be cavities or depressions in the seal edge to establish the spacing, particularly the depth of entry of the mask in the funnel.

Abstract: Sealing glass paste for sealing the face plate and funnel portion of a color television tube wherein PbO-containing sealing glass frit contains from at least 0.1 to 1.5% by weight of Pb.sub.3 O.sub.4 powder, which powder prevents the reduction of PbO to Pb metal during the sealing process, which reduction would otherwise result in a dielectric breakdown in the seal. A sealing glass paste consisting essentially of a PbO--B.sub.2 O.sub.3 --ZnO sealing glass frit and containing from at least 0.1 to 1.5% by weight of Pb.sub.3 O.sub.4 powder, based upon the weight of the frit, together with hydroxypropyl cellulose binder for the frit and a solvent for the binder. A method for sealing the face plate of a color television tube to its funnel portion with a PbO-containing solder glass wherein the reduction of PbO to metallic lead during the sealing step is obviated by the addition of a sufficient amount of Pb.sub.3 O.sub.4 powder in the solder glass and paste made therewith, which Pb.sub.3 O.sub.