Electric lamp and discharge devices – With luminescent solid or liquid material – Vacuum-type tube
Reexamination Certificate
2000-12-04
2003-05-27
Wong, Don (Department: 2821)
Electric lamp and discharge devices
With luminescent solid or liquid material
Vacuum-type tube
C313S521000
Reexamination Certificate
active
06570320
ABSTRACT:
BACKGROUND OF THE INVENTION
Electron tubes are often employed in technology, thus, for example, in electron microscopes or monitors. The object of many developments in the field of electron tubes is to improve the resolution of the devices wherein these tubes are employed. The resolution of such a device is dependent on, among other things, the electron gun that is integrated in the electron tube of the device. The electron gun generates an electron beam. It comprises an electron source and a suitable arrangement of electrodes. For example, a heated cathode that emits electrons excited by thermal energy comes into consideration as electron source. The electrodes serve as diaphragms of the focussing, of the intensity modulation and, potentially, of the deflection of the electron beam.
According to the current state of the art, electron guns of high-resolution monitors contain the following structure: the cathode and a first grid electrode are combined in a metal pot that is fused into a glass mount of the electron tube. Two further grid electrodes that are likewise fused into the glass mount are attached in a propagation direction of the electron beam.
In order to achieve an extremely high resolution of the monitor, the extremely fine through apertures of the grid electrodes or, respectively, electrode plates for electron focusing must be exactly circular and arranged exactly coaxially relative to one another. Over and above this, an extremely low-capacitance structure of the electrode arrangement is a basic pre-requisite for achieving a.high signal bandwidth.
These demands have not yet been satisfactorily met by the conventional tube technology. For example, the coaxial alignment of the through apertures for the electron beam is possible to only a limited extent due to the separate fusing of the electrodes in glass.
An alternative solution proceeds from U.S. Pat. No. 5,661,363. The apparatus disclosed here for shaping an electron beam is a ceramic body in monolithic multi-layer structure having at least electrode ceramic layer that comprises at least one through aperture for the electron beam. The electrode ceramic layer is composed of ruthenium oxide, an electrically conductive ceramic material. The electrode ceramic layer itself is thereby an electrode with whose assistance the electron beam can be shaped. In one embodiment, a plurality of electrode ceramic layers and insulating ceramic layers for insulation of the electrode ceramic layers are arranged in alternation in the propagation direction of the electron beam. Since a whole electrode ceramic layers respectively forms an electrode, a low-capacitance apparatus is difficult to achieve.
SUMMARY OF THE INVENTION
An object of the invention is to provide a low-capacitance means for shaping an electron beam and a method for the manufacture thereof.
This object is achieved by an apparatus for shaping an electron beam, composed of a ceramic body in monolithic multi-layer structure having at least one electrode ceramic layer that comprises at least one through aperture for the electron beam and at least one electrode arranged at the through aperture, the electrode ceramic layer comprises glass ceramic and the electrode is composed of an elementary metal.
In a preferred embodiment, the electrode is annularly arranged around the through aperture. At least two electrodes are successively arranged along the propagation direction of the electron beam. The body may have at least one insulating ceramic layer that comprises a through aperture for the electron beam. A plurality of electrode ceramic layers and insulating ceramic layers of the body may be arranged in alternation along the propagation direction of the electron beam. In one example, one electrode is electrically insulated from at least one second electrode. Further, one electrode is electrically conductively connected to at least one second electrode. Specifically, the body comprises at least one electrical contacting composed of said metal. The metal comprises at least one substance from the group of gold, copper, molybdenum, palladium, platinum, silver and/or tungsten.
An exemplary embodiment provides that a plurality of electrodes and electrical contactings are arranged such that a capacitance arrangement is formed whose capacitances lie below 3 pF. The body is connected by glass solder to a cathode for generating the electron beam.
The invention also relates to employment of an apparatus according to the foregoing for the intensity modulation and focusing of the electron beam.
A method for the manufacture of an apparatus includes:
at least two ceramic layers each having at least one through aperture for the electron are fabricated from a green ceramic film containing a binding agent, whereby at least one of the ceramic layers is fashioned as electrode ceramic layer;
the ceramic layers are stacked such upon employment of a first stacking device that the through apertures are arranged above one another; and
the ceramic layers are sintered to form the body under single-axis pressure and the sintering temperature of the ceramic material employed.
Preferably, for fabricating the ceramic layer,
at least one through aperture is produced in the green ceramic film;
at least two green ceramic films are stacked such upon employment of a second stacking device that the through apertures are arranged above one another;
the stacked green ceramic films are laminated to form a composite;
the composite is freed of the binding agent at elevated temperatures; and
the composite is pre-sintered to a ceramic layer at a temperature that lies under the sintering temperature of the ceramic material employed.
The method for fabricating the ceramic layer includes the manufacture of an electrical through-contacting in the ceramic layer, whereby
at least one contacting opening is produced in at least one green ceramic film, said contacting opening being filled with electrically conductive material. In a preferred development, electrically conductive material is applied on a surface of the ceramic layer following the pre-sintering for fabricating an electrode ceramic layer. Specifically, electrically conductive material is applied on the surface of at least one green ceramic film for fabricating an electrode ceramic layer. Exemplary embodiments of the method provide that at least one substance from the group of gold, copper, molybdenum, palladium, platinum, silver and/or tungsten is selected as electrically conductive material. For manufacturing the ceramic layer,
the green ceramic films are stacked such on top of one another that the uppermost and the lowest green ceramic film of the composite comprise ceramic material whose sintering temperature lies above that of the ceramic material that the green ceramic films lying therebetween in the composite comprise; and
the ceramic material sintering at the higher temperature is removed after the pre-sintering. In one embodiment, a green ceramic film that comprises aluminum oxide is employed as the first and last green ceramic film in the stacking.
According to the first mentioned embodiment, an apparatus for shaping an electron beam composed of a ceramic body in a monolithic multi-layer structure having at least one electrode ceramic layer is provided that has at least one through aperture for the electron beam and at least one electrode arranged at the through aperture. This apparatus is characterized in that the electrode ceramic layer comprises glass ceramic and the electrode is composed of an elementary metal.
This apparatus, which is referred to below as an electrode arrangement as well, comprises, for example, three electrodes and serves the purpose of focusing the electron beam in an electron gun.
The ceramic body is preferably shaped as a flat, round cylinder and has at least one through aperture through which the electron beam can be guided.
The electron arrangement is monolithically constructed of a plurality of ceramic layers. The individual ceramic layers are preferably differently constructed and thus also assume different functions. Electro
Burkhardt Klaus
Eckhardt Wolfgang
Gohlke Silvia
Männer Ruth
Wersing Wolfram
Dinh Trinh Vo
Wong Don
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