U.S. Philips Corporation

U.S. Phillips Corporation

U.S. Philips Corpration

Jan Hasker

Johannes M Van Esdonk

Josef J Van Lith

Paul D Goodell

Hendrik Roelofs

Pieter Hokkeling

Jacobus E Crombeen

Jacobus A Deckers

Cornelis Peters

Petrus R Van Ijzendoorn

Robert H Kane

Johannes Cornelis Vervest

Georg Friedrich Gartner

Jacobus Stoffels

Jacobus H Jacobs

Johannes A Verhoeven

Peter Opmeer

Anton K Niessen

Laurentius C Vroomen

Wim Kwestroo

Henricus J Stoffelen

Petrus A Van Dorst

A cathode having a matrix body (1) impregnated with an alkaline earth compound, whose surface is provided with a top coat (2, 3, 4) comprising a high melting point metal, such as particularly tungsten, and scandium. A high emission at a low operating temperature and simultaneously a rapid recuperation after ion bombardment as well as a long lifetime are achieved in that the top coat comprises at least two layers of different composition, with a purely metallic layer (5, 6, 7) being provided on the impregnated matrix body (1), which layer comprises scandium and a high melting point metal such as particularly tungsten and/or rhenium, and in that a metallic layer of a high melting point metal such as particularly tungsten is provided as a sealing layer.

Impregnated cathode with composite top coat

Method of manufacturing a dispenser cathode, in which method tungsten and a scandium-containing material are mechanically alloyed and the product thus formed is pressed into a cathode body. The cathode body is further provided with a barium-containing component. In the mechanical alloying process the tungsten is highly deformed and the scandium-containing material is mixed with the tungsten so as to be very finely distributed therein, so that an improved dispensation of scandium and hence an improved recovery after ion bombardment of the final cathode is attained.

Dispenser cathode and method of manufacturing a dispenser cathode

Method of manufacturing a dispenser cathode

A cathode body for an impregnated scandate cathode is obtained by compressing and sintering a mixture of tungsten powder with approximately 0.5% by weight of scandium, whereafter the body is impregnated.

Scandate cathode

For maintaining a monolayer of scandium which is necessary for a satisfactory emission on the surface of a scandate cathode, at least the top layer of the cathode is provided with scandium coated with a scandium oxide film. Even after repeated ion bombardment the emission is found to recover up to approximately 90% of the initial value at a current density of ca. 100 A/cm.sup.2.

Method of manufacturing scandate cathode with scandium oxide film

By providing at least the top layer of the matrix of a scandate cathode with an alloy or compound which exhibits scandium segregation, a satisfactory recovery for cathodes with a high emission can be achieved after ion bombardment.

Scandate cathode exhibiting scandium segregation

An oxide cathode comprising a base 1 which consists substantially of titanium and a heater element 5 coated with aluminium oxide 6 to heat the base 1, which bears a porous alkaline earth metal oxide emissive layer 4. When the surface of the titanium base 1 which is opposed to the heater element 5 bears a metal layer 7 consisting at least of one of the metals Pt, Mo, Ta and W, a solution is obtained to the problem occurring in titanium cathodes in that titanium in contact with aluminium oxide is not chemically stable. The metal layer preferably consisits of pure tungsten and is formed by chemical vapour desposition (CVD). The metal layer is preferably from 1 to 10 .mu.m thick.

Oxide cathode

A method of manufacturing a scandate dispenser cathode having a matrix (1) at least the top layer of which consists substantially of a mixture of tungsten with scandium oxide or with a mixed oxide comprising scandium oxide. When sintering of the matrix is carried out at a temperature between 1300.degree. and 1700.degree. C., preferably at approximately 1500.degree. C. and in a hydrogen atmosphere, cathodes are obtained having a better recovery after ion bombardment compared with cathodes sintered at 1900.degree. C. Sintering in hydrogen results in a better reproducibility.

Method of manufacturing a scandate dispenser cathode and scandate

A method of manufacturing a scandate dispenser cathode having a matrix at least the top layer of which at the surface consists substantially of tungsten (W) and scandium oxide (Sc.sub.2 O.sub.3) and with emitter material in or below said matrix. If said method comprises the following steps:

Method of manufacturing a scandate dispenser cathode and dispenser

An oxide cathode comprising a metal base substantially consisting of titanium and a heating element for heating said base, on which base a porous layer comprising an alkaline earth metal oxide is provided. The cathode has a comparatively low operating temperature, a short warm up time and a low power requirement.

Low-pressure discharge lamp having an elongate discharge vessel which contains a thinly distributed filamentary body permeable to the gas discharge, said body comprising a helical support filament which is supported by the inner surface of the discharge vessel and is at least one further filament, supported by the support filament and extending therefrom towards the axis fo the discharge vessel.

Low-pressure gas discharge lamp and method for making

A low pressure gas discharge lamp having a body present in the discharge vessel which consists of a longitudinal support which extends into the longitudinal direction of the vessel, the support being provided with fibers which are distributed over the space within the discharge vessel and extend substantially transversely from the support.

Low pressure gas discharge lamp having fibers evenly distributed between

A method of producing low-pressure gas discharge lamps wherein filamenting wool is prepared into a mat and then brought into the discharge space.

Method of producing a low-pressure gas discharge lamp

A low-pressure gas discharge lamp in which thin-structured bodies are present in the discharge space for increasing the radiation output per unit volume.

Low-pressure gas discharge lamp

A method for manufacturing a low pressure gas discharge lamp having a body present in the discharge vessel which consists of a longitudinal support which extends into the longitudinal direction of the vessel. The support being provided with fibres which are distributed over the space within the discharge vessel and extend substantially transversely from the support.

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Eindhoven, Netherlands

Jan Hasker