General Electric Company

Jack M Strok

Curtis E Scott

Thomas G Parham

Gary Robert Allen

Charles D Greskovich

Lionel M Levinson

Rolf S Bergman

Istvan Csanyi

Karthik Sivaraman

Douglas G Seredich

Martin L Panchula

Balazs Nyiri

Istv&aacute;n Cs&aacute;nyi

John H Ingold

J&aacute;nos Sneider

Zolt&aacute;n T&oacute;th

A discharge chamber for a lamp, the discharge chamber comprising a monolithic ceramic article having a main body defining an arc chamber and generally opposed leg members defining openings which may accommodate an electrode or electrode lead through. A method of making a ceramic discharge chamber comprising the steps of forming a mixture comprised of ceramic powder and a binder and injecting the mixture into a die and around a mold to form at least a main body of the discharge chamber.

Ceramic discharge chamber for a discharge lamp

An arc discharge vessel having electrodes disposed therein, a fill within the discharge vessel wherein the arc discharge vessel is comprised of alumina including the following dopants in parts per million: 50&lE;MgO&lE;1500; 100&lE;HFO &lE;1500; 0&lE;ZrO &lE;700; 0&lE;Y O &lE;300; 0&lE;Sc O &lE;1000; 0&lE;Dy O &lE;1000; 0&lE;Tb O &lE;1000; with the proviso that at least 5 ppm Y O , Sc O , Dy O , Tb O , or mixtures thereof is included.

High pressure discharge lamp

An arc discharge lamp comprising an arc tube including a starting aid is described. The starting aid comprises at least one metal cermet coating applied to the surface of the arc tube, or a metal layer including refractory glass disposed over said cermet coating or said metal layer.

Means for applying conducting members to arc tubes

A mercury-free high pressure sodium vapor lamp is dosed with sodium, xenon and zinc as an elemental metal additive. The addition of the metal additive prevents an undesirable low-voltage operating mode of the sodium-xenon discharge associated with a mercury-free HPS lamp, which otherwise occurs when sodium is no longer available to participate in the arc discharge.

Sodium-xenon lamp with improved characteristics at end-of-life

A vapor discharge lamp comprised of an arc tube containing an ionizable medium, a first electrode electrically connected to a first in lead conductor, and a second electrode electrically connected to a second in lead conductor, said first and said second electrode pairs being positioned to create an arc discharge therebetween, an electron emissive material disposed on at least one of said electrodes, said electron emissive material being Ba.sub.4 Al.sub.2 O.sub.7.

Discharge lamp emission material

A metal halide arc tube is provided having a light-transmitting envelope and electrodes for generating an arc discharge within a sealed chamber of the envelope. The envelope includes a transparent film at a cold region of the sealed chamber where metal halides migrate and condense. The transparent film transmits visible radiation and absorbs ultraviolet radiation emitted by the arc to impose an additional heat load on the cold region so that a high metal halide vapor pressure can be maintained. The temperature of a hot region of the envelope can be maintained at a lower level by reducing power input or increasing chamber surface area. Preferably, the transparent film reflects infrared radiation emitted by the light source back to the arc to increase efficiency and further increase the temperature of the cold region due to decreased thermal emittance. The transparent film is preferably a dichroic coating having alternating layers of high and low index of refraction refractory materials.

Transparent heat conserving coating for metal halide arc tubes

A solid state seed crystal process for bulk conversion of a polycrystalline ceramic body to a single crystal body (of the same chemical composition) having the same crystal orientation as the seed crystal. The process comprises heating said body to form a monolithic join between the body and the seed crystal, heating the joined structure to reduce grain growth inhibitors and further heating the joined structure above the minimum temperature required for crystallite growth of the crystalline material, but not hot enough to melt and distort the original shape of the polycrystalline ceramic body during its conversion to a single crystal. This process has been used to convert polycrystalline alumina (PCA) bodies to sapphire having the same crystal orientation as the seed crystal by heating the PCA body, monolithically joined to a sapphire seed crystal, at a temperature above 1700.degree. C. without melting the body.

Solid state thermal conversion of polycrystalline alumina to sapphire

Reflector lamps having vitreous, light transmissive reflectors and containing a source of visible and UV light radiation produce little or no UV radiation in the projected light beam by having a light reflecting coating on the exterior surface of the reflector and the reflector made of UV absorbing glass or having a UV absorbing coating disposed between the light reflecting coating and the exterior reflector surface. An anti-reflecting coating disposed on the interior, light-receiving surface of the reflector reduces UV emission still further.

Reflector lamp with low UV emission

An alkali metal vapor arc discharge lamp which operates on DC and employs an amalgam of mercury and an alkali metal such as sodium, has a cathode to anode pressure ratio no greater than 5 and a cathode end temperature at least 50.degree. C. hotter than the anode end temperature to prevent cataphoretic separation of the mercury and alkali metal in the arc discharge during operation of the lamp. The lamp is designed to have a cataphoretic driving parameter (CDP) value of less than 150. The CDP is defined as the product of the arc current in amperes, times the arc gap length in centimeters, divided by square of the inner diameter of the arc tube in centimeters.

DC operated sodium vapor lamp

An improved high pressure sodium vapor lamp construction is provided for operation on sonic frequency pulses without excessive acoustic noise. The novel jacketed lamp construction employs non-magnetostrictive metal for the frame employed to suspend a ceramic arc tube within the outer jacket in combination with a particular orientation or placement for ring getter elements located within said outer envelope. Various lamp constructions embodying such improvement are disclosed to enable relatively noise free lamp operation.

Sodium vapor lamp for sonic pulse operation

The life and performance of high pressure sodium vapor lamps using double wire ceramic seals and no exhaust tube is improved by an end closure and inlead structure which prevents condensation of sodium-mercury amalgam on sealing frit. One end of the arc tube has a plug portion which forms an integral part of the alumina tube without any sealing frit or glass intervening between portions. The plug portion includes a pedestal portion which projects inwardly from the outer region which is joined to the tube. The pedestal defines with the tube wall a ring chamber in which excess amalgam collects out of contact with any sealing frit. The other end of the tube is conventionally sealed by using sealing frit to cement an alumina plug but it is designed to run hotter to prevent condensation of amalgam at that end.

Ceramic lamp end closure and inlead structure

A high pressure sodium vapor lamp having a time fuse device effective for predeterminedly establishing the anticipated life of the high pressure lamp is disclosed. Also disclosed are various embodiments of the time fuse device.

Time fuse for high pressure sodium lamps

A high pressure sodium lamp operated at increased pressure and having an improved color rendition is disclosed. The improved high pressure sodium lamp has an arc tube which reduces the sodium losses typically experienced by high pressure operation.

High pressure sodium lamp having improved coloring rendition

A high pressure metal (sodium) vapor lamp comprises an outer vitreous envelope and an inner ceramic arc tube supported within it. The arc tube contains vaporizable metal in excess of the quantity vaporized in operation and the heat balance determines a cold spot whereat excess metal collects. The temperature of the cold spot determines the metal vapor pressure and the voltage drop across the lamp which must lie between specified limits. A thermal link is provided to a metal member such as the exhaust tube the heat loss from which influences significantly the temperature of the cold spot. In completed lamps measuring too low in voltage, such thermal link may be partly severed without breaking open the outer envelope in order to raise the voltage. One convenient way utilizes an auxiliary wire which is cut by aiming a laser beam at it.

Metal vapor arc lamp having thermal link diminishable in heat conduction

A high pressure alkali metal vapor lamp envelope of alumina ceramic has an externally projecting metal tube serving as an inlead and as a reservoir for excess sodium-mercury amalgam. The ability of the lamp to withstand heavy vibration without the occurrence of voltage rise and drop-out caused by expulsion of amalgam droplets from the reservoir is enhanced by flattening the end portion of the metal tube to a least dimension adequate to increase the capillary attraction to better than twice the force of gravity.

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Garrettsville, OH, United States of America

Jack M Strok