Abstract: A grid-controlled electron source comprises an apertured grid spaced in front of a thermionic cathode. Areas of the cathode directly behind the grid conductors are made non-emissive by a bonded surface layer of non-emissive material such as zirconium. On porous metal cathodes impregnated with active emitting material the metal surface may be sealed with a dense layer of inactive metal under the non-emissive layer to prevent chemical reaction of the latter with the emitting material.Methods of depositing the surface layers in the desired pattern include coating the cathode's entire large-scale surface contour, followed by machining small concave dimples into the surface, thereby removing the non-emissive layer from the dimpled surfaces from which small beamlets of electrons are focused between the grid conductors without grid interception.Another method is to mask the desired non-emissive areas with an apertured mask having solid elements registered with the desired positions of the grid conductors.

Abstract: In a radio frequency transistor package, a layer of metallization is deposited on an electrically insulative thermally conductive ceramic substrate member serving as a heat sink. An insular region of the metallization serves as a pad for receiving a transistor die with the collector region of the transistor bonded to the insular region of metallization. The region of the metallization surrounding the pad comprises a ground plane. An apertured ceramic insulative spacer is bonded over the ground plane metallization with the aperture in registration over the transistor. Input, output and a pair of common lead metal strips are bonded to the upper surface of the spacer in generally coplanar configuration. The two common leads extend across the spacer adjacent opposite sides of the aperture in generally tangential relation thereto. The input and output leads are disposed in between the common leads and are interrupted by the central aperture in the spacer.

Abstract: A long wavelength photoemitter, for example a III-V semiconductor, having a work function reduction activation layer thereon, with means for overcoming the energy barrier between the semiconductor conduction band edge and the vacuum comprising means for thermally energizing the photoexcited electrons in the conduction band from a lower energy level therein to a higher "metastable" energy level in which they may reside for a sufficient time such that the electrons can pass with high probability from the elevated energy level into the vacuum over the energy barrier. In one embodiment, promotion of electrons to this higher energy level in the conduction band results from proper selection of the semiconductor alloy with conduction band levels favoring such room temperature thermal excitation.

Abstract: The charge image bearing surface of a web to be developed is partially wrapped around the periphery of a perforated rotatable drum-shaped development electrode. Liquid electrographic toner is forced through the perforated drum against the charge image bearing surface of the recording web for developing the electrostatic image thereon. The drum is rotated to provide a peripheral velocity substantially different than the velocity of the web being developed such as to produce a sliding action between the periphery of the drum and the web. In this manner, the relatively stationary boundary layer of depleted liquid toner carried by the web is disturbed such that the pigment particle depleted layer of toner is replenished by toner forced through the perforated development electrode.

Abstract: In an image tube, a photocathode is disposed to receive a photon image for emitting into the tube a corresponding electron image which is accelerated by an accelerating anode and focused upon an output device, such as a fluorescent screen or a microchannel electron multiplier. A gating electrode is interposed along the beam path between the anode and the output device. The potential difference between the photocathode and the gating electrode is periodically pulsed such that the gating electrode is sufficiently negative relative to the potential of the photocathode for reflecting the image electrons passing through the anode back to the anode for collection thereof and thus for gating off the electron image to the output device. This potential difference may be pulsed by pulsing the photocathode positive with respect to the gating electrode or by pulsing the gating electrode negative with respect to the photocathode.

Abstract: A grid electrode for an electron tube with planar electrodes consists of a planar array of fine wires mounted on a support frame. The support frame has a circular outside rim and interconnected interior elements dividing the area inside the rim into three or more separated apertures. The interior elements include radial elements connected to non-radial elements, forming a mechanically rigid structure with good heat conduction to the outside rim which resists buckling out of its plane when differentially heated.