In a cold cathode consisting of a layer of aluminum oxide between a plate and a grid, the aluminum oxide is formed on aluminum as a porous oxide layer. The meshes of the grid are so fine that the grid is attracted against the oxide due to the voltage difference with the plate.

A support for the grid structure of a cathode-ray tube in which the support is stressed to compensate for any expansion of the grid wires due to heating, the support having a pair of opposed parallel arms with the grid wires attached to and extending transversely between the arms, and a pair of braces supporting the arms at the Bessel points, the braces being stressed in a direction substantially parallel to the direction of the grid wires so that as the grid wires expand due to heat the braces ...

In a reticulated grid cathode which has a flexible connection at one end to the conductor for the filament current present inside the cathode, the flexible connection consists of a number of thin metal strips of the same thickness. The strips constitute an approximately semi-circular arc and each consist of two strips of preferably the same thickness. In order to minimize the bending stress occurring in the strips, the diameter of the arc formed by the strips is chosen to be as large as possible...

Thermal conductivity is increased and secondary emission reduced by plating a preliminarily formed grid with copper and then overplating with gold or silver.

In mesh grids of comparatively large dimensions, measures are taken to prevent that said grids which are mainly used in metal-ceramic tubes deform under the influence of their own weight at high temperature. A sufficient increase of the mechanical stability of the grid is obtained if said grid comprises a few thicker wires in addition to the thin wires.

A meshed cathode structure particularly for use in high power grid-controlled transmitting tubes comprises an electrically conductive tubular current lead-in member provided with a frusto-conical support which is also electrically conductive. The periphery of the frusto-conical support is provided with circular arrays of uniformly spaced apertures and recesses, the arrays being offset circumferentially relative to one another, and the adjoining ends of two cylindrical meshed cathode components a...

A grid gates a stream of ions when a D.C. potential is applied between two sets of interdigitated wires included in the grid to produce a D.C. field. The improved grid disclosed herein contains the two sets of interdigitated wires in a single plane so that the D.C. field is precisely normal to the ion current flow direction to prevent a residual ion current flow when the grid provides the gating effect.

A television camera tube comprising an evacuated envelope enclosing an electron gun. The electron gun has, in the direction of propagation of the generated electron beam, a cathode, a grid, an anode and a cylindrical electrode. The cylindrical electrode has a diaphragm. The anode has a portion that extends substantially perpendicularly to the electron beam and includes an aperture. A first metal foil is provided on the side of the anode toward the target. The metal foil covers the aperture of th...

In an electron tube having coaxial cylindrical electrodes and at least one cylindrical grid of pyrolytic graphite, the grid is joined to the upper portion of a central conducting mast by means of a bell which is also of pyrolytic graphite and fixed on the mast. Slits are cut at uniform intervals around the periphery of the bell in order to form resilient strips which serve to establish an electrical contact between the grid and the conducting mast.

A power amplifier valve with a grid is disclosed having improved reliability of operation and lifetime of the valve. A screen grid of a tetrode has a mesh grid with vertical or oblique rods in pyrolytic graphite. According to the invention, the rods are provided with a greater width at the bottom of the grid near the output of the valve where the high-frequency currents are greatest.