Abstract: Piled-up films composed of different materials or composed of the same material manufactured by different methods or different conditions are used as an insulating layer for a field-emission cold cathode. The insulating layer may have a composition which is varied continuously in the thickness direction. A cross-section of the insulating layer may be made uneven. Preferably, a triple junction in which a substrate, the insulating layer, and a vacuum are in contact with one another, is disposed at a position which can not be seen from outside the device.

Abstract: In this field emission cold cathode apparatus, the heater shares at least one terminal with the other components, namely, the emitter electrode, the gate electrode, the focus electrode. With this structure, gases absorbed into a surface of the emitters can be released out from the emitters, by heating emitters with the heater. In addition, this apparatus can avoid the increase in the number of the terminal compared with the conventional apparatus having a heater.

Abstract: A field emission type cold cathode includes a gate electrode (5), and insulating layer (4) disposed under the gate electrode (5), and emitter cones (7) respectively disposed in cavities penetrating through the insulating layer (4) and the gate electrode (5). The cathode includes a conductive layer (3) which is in contact with the emitter cones (7), and a second insulating layer (2) in the form of a plurality of islands and disposed between the conductive layer (3) and a substrate (1). The conductive layer (3) is electrically connected to the substrate (1) at contact regions. In a preferred embodiment, the conductive layer (3) has pocket regions (3c) for connecting the conductive layer (3) with the substrate (1). The pockets (3c) have a first conductivity, wherein the conductive layer (3) has a second conductivity in the regions that are proximate to the areas in contact with the cones (7). The second conductivity is greater than the first conductivity.

Abstract: In a field emission cathode, periphery portions of opening portions of a gate electrode are recessed on a side of a substrate, and a focusing electrode having opening portions which are identical in number with the opening portions of the gate electrode are disposed on the gate electrode. Further, a shield electrode having opening portions which are identical in number with opening portions of the gate electrode are disposed between the gate electrode and the focusing electrode. According to the above-mentioned construction, a focusing aberration can be reduced, and a focused electron flow can be obtained by a low electric potential of the gate electrode.

Abstract: A field emission cold cathode includes a conductive substrate (1), an insulating layer (2) disposed on the substrate (1), a gate electrode (3) disposed on the insulating layer (2), cavities (4) extending through the gate electrode (3) and the insulating layer (2), and emitter cones (6) disposed on the substrate (1) within the cavities (4). The gate electrode further includes high resistance areas (5) disposed around the tips of the emitter cones (6) that enables the field emission cold cathode to operate in the event of a short circuit between the gate electrode (3) and an emitter cone (6) due to electrically conductive foreign material entering a cavity (4). The field emission cold cathode can be use in an electron gun.

Abstract: A field emission cold cathode comprises a conductive substrate, an insulating layer formed on the substrate and having plural cavities each for receiving an emitter, a gate electrode for applying a high electric field to the tips of emitters. An annular portion of the gate electrode each defining an opening overlapping corresponding cavity is located at a distance from the substrate smaller than the distance between another portion of the gate electrode and the substrate. Parasitic capacitance between the gate electrode and the cold cathode including the substrate and the emitter is reduced due to the large distance between the another portion of the gate electrode and the substrate. Between the another portion and the substrate, a second insulating layer or a gap is disposed. The field emission is cold cathode can function in a high frequency range while fabricating conical emitters with a small height due to the small distance between the annular portions and the substrate.

Abstract: A field emission cold cathode element having a conducting substrate, a dielectric layer which is on the substrate and has holes, emitter electrodes each of which have a sharp-pointed tip and stand on the substrate in the respective holes in the dielectric layer, and a gate electrode layer which is on the dielectric layer and has apertures right above the respective holes in the dielectric layer. The tip of each emitter electrode is near or in the aperture in the gate electrode layer, and the emission current depends on the position of the emitter tip relative to the gate electrode. The dielectric layer and the gate electrode layer are largely removed so as to remain only in limited first regions which are around the holes for the respective emitter electrodes and limited second regions each of which connects one of the first regions to another. The partial removal of the dielectric and gate electrode layers is for reducing interlayer stresses induced by temperature changes.

Abstract: A field emission cold cathode element having a conducting substrate, a dielectric layer which is on the substrate and has holes, emitter electrodes which have a sharp-pointed tip and stand on the substrate in the respective holes in the dielectric layer, and a gate electrode which is on the dielectric layer and has apertures right above the respective holes in the dielectric layer. The tip of each emitter electrode is near or in the aperture in the gate electrode layer. The dielectric layer is largely removed so as to remain only in limited regions around the holes for the respective emitter electrodes, and a gate electrode layer is formed with, in addition to the apertures for the emitter electrodes, a number of holes in regions where the substrate surface is exposed by removal of the dielectric layer. The partial removal of the dielectric and gate electrode layers has the effect of reducing interlayer stresses induced by temperature changes, so that the gate electrode layer can be made desirably thick.

Abstract: Disclosed is a field emission device which has an emitter formed in the center portion where ion bombardment is likely to occur, and a gate formed partially thicker, or which has a metal layer with the same potential as the emitter and a high melting point, formed in the center portion of the cathode. Therefore, even bombardment of positive ions at the center portion of the cold field emission device will not affect the electron emission, thereby ensuring an always stable cathode current or electron beam. Further, as the field emission device is designed to prevent the deterioration of the insulation between the emitter and gate, abrupt stopping of the electron emission hardly occurs. Therefore, an electron tube using this field emission device has a stable function and high reliability.

Abstract: A field emission cathode includes a conductive substrate (1) having emitters (4) formed thereon, a contact hole (5) extending therethrough, and a conductive layer (7) formed within the contact hole (5) thereby extending through the conductive substrate (1). A gate electrode (3) and the conductive layer (7) are insulated from the conductive substrate (1) by an insulating layer (2). The gate electrode (3) is connected to a first pull-out electrode (6) via the conductive layer (7), and the emitters (4) are connected to a second pull-out electrode (8) via the conductive substrate (1) thereby eliminating the need for bonding wires.

Abstract: The subject is a field emission cold cathode element having a conducting substrate, a dielectric layer which is on the substrate and has holes, emitter electrodes which have a sharp-pointed tip and stand on the substrate in the respective holes in the dielectric layer and a gate electrode layer which is on the dielectric layer and has apertures right above the respective holes in the dielectric layer. The tip of each emitter electrode is near or in the aperture in the gate electrode layer, and the emission current depends on the position of the emitter tip relative to the gate electrode. According to the invention, the gate electrode layer is made relatively thick in limited regions surrounding the respective apertures and relatively thin in other regions to compensate for inevitable variations in the emitter electrode heights without augmenting interlayer stresses attributed to different thermal expansions of the gate electrode and dielectric layers.

Abstract: A field emission cold cathode includes a conductive substrate, an insulating layer formed on the substrate and having plural cavities each for receiving an emitter, a gate electrode for applying a high electric field to the tips of emitters. An annular portion of the gate electrode defines an opening of a corresponding cavity is located at a distance from the substrate smaller than the distance between an elevated middle portion of the gate electrode and the substrate. Parasitic capacitance between the gate electrode and the cold cathode including the substrate and the emitter is reduced due to the large distance between the elevated middle portion of the gate electrode and the substrate. Between the elevated middle portion and the substrate, a second insulating layer or a gap is disposed. The field emission cold cathode can function in a high frequency range while fabricating conical emitters with a small height due to the small distance between the annular portions and the substrate.

Abstract: A heater coil for an electron tube includes a spiral wire which is double wound to be cylindrical, and a connection wire which is formed on an upper face of the spiral wire in a horizontal plane. The connection wire is shaped to have at least two bent portions on the same plane.