Electron beam device having a glass envelope and a focussing lens provided thereon
AssigneePhilips Electronics North American Corporation
InventorsWilliam N. Osborne, Petrus J. M. Prinsen, Edwin A. Montie
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Abstract
A focussing lens for an electron beam device is formed by a helically coiled resistance layer of a fired suspension of a conductive material of a mixture of a lead rathenate, a lead titanate and a ruthenium oxide in a glass formed of silicon dioxide, aluminum oxide and lead oxide.
Claims9
A cathode ray tube comprising a glass envelope consisting of a display window, a cone and a neck and an electron gun situated inside said envelope opposite said window and having at least one focussing lens provided on an inside surface of said neck, the improvement wherein said at least one focussing lens is a helically coiled resistance layer formed of a suspension, by weight, of about 33%-50% of a conductive material comprising about 40%-60% of a lead ruthenate, about 25%-38% of a lead titanate and about 2%-15% of a ruthenium oxide in about 50%-67% of a glass comprising about 30%-40% of SiO.sub.2, about 3%-7.5% of Al.sub.2 O.sub.3 and about 53%-67% of PbO provided on said surface.
An electron beam device including an electron gun comprising electron-beam means for producing an electron beam directed to a surface and focusing means for producing a focusing lens field for focusing said electron beam to a spot on said surface, said focusing means comprising;
- an elongated tubular glass member positioned around a central axis of said electron gun, said tubular glass member being provided on an inner surface thereof with at least one focusing lens, said at least one focusing lens being a helically coiled resistance layer formed of a suspension, by weight, of about 33%-50% of a conductive material comprising about 40%-60% of a lead ruthenate, about 25%-38% of a lead titanate and about 2%-15% of a ruthenium oxide in about 50%-67% of a glass comprising about 30%-40% of SiO.sub.2, about 3%-7.5% of Al.sub.2 O.sub.3 and about 53%-67% of PbO provided on said surface.
Dependencies are inferred from the claim text.