Philips Electronics North America Corporation

U.S. Philips Corporation

Susan McGee

Vivek Mehrotra

Thomas F McGee

Hemant S Betrabet

Edward Young

Jeroen Langevoort

Jose Azevedo

Thomas Caulfield

David R Woodward

Hui-Meng Chow

Thomas O Leyh

Otmar H Boser

Robert H Kane

Novel emitter materials, electrode assemblies amd lamps comprising the same are provided in which, in accordance with the invention, novel electrodes are provided having a lamp electrode structure, preferably including a hollow ferrule for sealing in a lamp to permit evacuation; an emitter material of the invention on at least one surface thereof, preferably on a protrusion attached to the hollow ferrule; a thermal isolator, preferably in the form of a low thermal conductivity wire or an incised or cut-out portion of the hollow ferrule body, for thermally isolating the protrusion from the ferrule to maintain a sufficiently high temperature for thermionic emission, and further comprising an emitter material requiring no in-lamp processing. The emitter materials are a mixed oxide of Ba, Sr and mixtures thereof with one or more of the metals from the series comprising Ta, Ti, Zr, Sc, Y, and La, are preferably selected from the group consisting of Ba.sub.4 Ta.sub.2 O.sub.9, Ba.sub.5 Ta.sub.4 O.sub.15, BaY.sub.2 O.sub.4, BaCeO.sub.3, Ba.sub.x Sr.sub.1-x Y.sub.2 O.sub.4, Ba.sub.2 TiO.sub.4, BaZrO.sub.3, Ba.sub.x Sr.sub.1-x TiO.sub.3, and Ba.sub.x Sr.sub.1-x ZrO.sub.3, wherein x ranges from a value of 0 to 1, and are most preferably one or more mixed oxides selected from the group consisting of Ba.sub.4 Ta.sub.2 O.sub.9, BaY.sub.2 O.sub.4, BaCeO.sub.3, Ba.sub.0.5 Sr.sub.0.5 Y.sub.2 O.sub.4, Ba.sub.0.75 Sr.sub.0.25 Y.sub.2 O.sub.4, Ba.sub.2 TiO.sub.4, BaZrO.sub.3, Ba.sub.0.5 Sr.sub.0.5 TiO.sub.3, and Ba.sub.0.5 Sr.sub.0.5 ZrO.sub.3.

Hollow electrodes for low pressure discharge lamps, particularly narrow

Novel emitter materials, electrode assemblies amd lamps comprisinfg the same are provided in which, in accordance with the invention, novel electrodes are provided having a lamp electrode structure, preferably including a hollow ferrule for sealing in a lamp to permit evacuation; an emitter material of the invention on at least one surface thereof, preferably on a protrusion attached to the hollow ferrule; a thermal isolator, preferably in the form of a low thermal conductivity wire or an incised or cut-out portion of the hollow ferrule body, for thermally isolating the protrusion from the ferrule to maintain a sufficiently high temperature for thermionic emission, and further comprising an emitter material requiring no in-lamp processing. The emitter materials are a mixed oxide of Ba, Sr and mixtures thereof with one or more of the metals from the series comprising Ta, Ti, Zr, Sc, Y, and La, are preferably selected from the group consisting of Ba.sub.4 Ta.sub.2 O.sub.9, Ba.sub.5 Ta.sub.4 O.sub.15, BaY.sub.2 O.sub.4, BaCeO.sub.3, Ba.sub.x Sr.sub.1-x Y.sub.2 O.sub.4, Ba.sub.2 TiO.sub.4, BaZrO.sub.3, Ba.sub.x Sr.sub.1-x TiO.sub.3, and Ba.sub.x Sr.sub.1-x ZrO.sub.3, wherein x ranges from a value of 0 to 1, and are most preferably one or more mixed oxides selected from the group consisting of Ba.sub.4 Ta.sub.2 O.sub.9, BaY.sub.2 O.sub.4, BaCeO.sub.3, Ba.sub.0.5 Sr.sub.0.5 Y.sub.2 O.sub.4, Ba.sub.0.75 Sr.sub.0.25 Y.sub.2 O.sub.4, Ba.sub.2 TiO.sub.4, BaZrO.sub.3, Ba.sub.0.5 Sr.sub.0.5 TiO.sub.3, and Ba.sub.0.5 Sr.sub.0.5 ZrO.sub.3.

An electric gas discharge lamp includes an electrode having a tip portion comprised by a mesh body carrying an emitter material. The mesh body in a favorable embodiment is circular cylindrical and is attached via an electrically conductive thermal isolator to a conductive feed-through, such as a hollow ferrule, extending through a seal of the lamp vessel. As compared to a continuous walled tip portion of similar shape and material, the mesh body has a lower mass and heat capacity, and can therefore be operated at higher temperatures without increasing the temperature of the seal area. The higher operating temperature of the tip portion promotes greater electron emission from the emitter material, and therefore a lower cathode fall. A lower cathode fall enables the lamp to be operated at higher lamp currents for greater light output. The mesh body also has the capability to reduce sputtering from the electrode through improved adhesion of the emitter material to the tip portion and faster attainment of its nominal operating temperature as compared to a smooth continuous walled body. In a favorable embodiment, the lamp is a low pressure discharge lamp having an inside diameter of less than about 5 mm.

Gas discharge lamp having an electrode with a low heat capacity tip

Composite sintered electrodes with improved properties that make them suitable for use in a variety of lamp types, are provided which comprise a refractory metal and a substantial amount of a refractory emitter oxide, either single layer or multiple layer, the composites having been subjected to sintering at an elevated temperature effective to form a composite electrode having a density of at least 85%, preferably in the presence of a sintering activator, such as for example, Ni, or mixture thereof with a sintering aid such as, for example, Li.sub.2 O.

Multiple layer composite electrodes for discharge lamps

Lamps that include composite sintered electrodes with improved properties that make them suitable for use in a variety of lamp types, are provided by a method for producing electrodes which comprise a refractory metal and a refractory emitter oxide, either single layer or multiple layer, the composites having been subjected to sintering at an elevated temperature effective to form a composite electrode having a density of at least 85%, preferably in the presence of a sintering activator, such as for example, Ni, or mixture thereof with a sintering aid such as, for example Li.sub.2 O.

Multiple layer composite electrodes for discharge lamps and low

The present invention is directed to new electrode structures for use in fluorescent lamps in which a tungsten base structure is provided with electron emissive materials including one or more of barium titanate, barium zirconate, barium strontium zirconate, barium cerium oxide, barium tantalate, and barium strontium yittrium oxide. Amounts of MgO may be added to improve or change emitter properties. A composite electrode structure can be formed by way of coating a tungsten coil with a slurry of this material, or providing powdered mixtures of both the electron emissive material and tungsten material and sintering this powdered material into a high density composite electrode structure.

Emission materials for discharge lamps and method for manufacturing

An improved dispersion strengthened lead-tin alloy solder is provided in which there is dispersed in the solder up to about 5 vol. percent of small particles, of a metal sulfide or a nickel-tin intermetallic.

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Peekskill, NY, United States of America

Susan McGee