Resistive primer coating for cathode-ray tube

Abstract

A display apparatus comprising an evacuated envelope having an interior surface and an exterior surface is disclosed. The envelope includes a faceplate having a luminescent screen on the interior surface thereof. An electron gun is disposed within a neck of the envelope for generating at least one electron beam that is directed toward the luminescent screen. A funnel connects the neck of the envelope with the faceplate. A deflection yoke is disposed around the envelope at the junction of the neck and the funnel. The yoke is attached to the envelope with an adhesive. A resistive primer coating is disposed on the envelope and forms a barrier between the yoke adhesive and the envelope. The resistive primer coating is formed from an aqueous formulation comprising a copolymer of chloroprene and methacrylic acid, a conductive filler material and at least one cross-linking agent.

Description

technical field [0001] The present invention relates to display devices, such as cathode ray tubes (CRTs) to which deflection yokes are attached, and more particularly to a resistive primer which provides isolation between the deflection yokes and the tube. Background technique [0002] Displays, such as television picture tubes or cathode ray tubes (CRTs), generally include a faceplate and a tube neck joined by a rectangular funnel-shaped body. The three-color fluorescent screen is located on the inner surface of the screen panel. The electron gun is placed in the neck of the tube to generate at least one, preferably three, electron beams directly directed to the three-color fluorescent screen. [0003] The inner surface of the rectangular funnel-shaped body is coated with a first conductive coating extending from the electron gun to the fluorescent screen, while the outer surface of the funnel-shaped body is partially coated with a second conductive coating. The conducti...

AI Technical Summary

Problems solved by technology

Conventional high resistance coatings including polychloroprene may not be suitable for deflection yoke mounting as their high resistance tends to decrease when heated to the temperatures used for adhesive curing

Also, the bond strength of polychloroprene resistive coatings to many hot melt adhesives used to secure deflection yokes to highly resistive coatings is poor at high humidity.

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