General Electric Company

Curtis E Scott

Mary Sue Kaliszewski

Charles D Greskovich

Lionel M Levinson

James Anthony Brewer

Jack M Strok

Venkat Subramaniam Venkataramani

Mark E Duffy

Charles I McVey

Paul G Mathews

Frederick W Dynys

Karthik Sivaraman

Mohan Rajaram

Martin L Panchula

Thomas G Parham

George E Sakoske

Edward James Balaschak

Vito J Arsena

Douglas G Seredich

Spiro Vamvakas

George Eric Coxon

Randolph E Maxwell

Joseph A Shrawder

Gary Robert Allen

Marshall Gordon Jones

Thomas Frederick Soules

Svante Prochazka

James T Dakin

Edward E Hammer

Frederic F Ahlgren

Donald R Schindler

Richard J Charles

Rolf S Bergman

Raymond A Heindl

Timothy D Russell

Carl Edward Erikson

Michael M Secen

Frederick Hetzel

Ronald James Olwert

Joseph C Oberle

Timothy A Taubert

Harihar D Chevali

Lawrence T Mazza

Mahomed Hanif Girach

Ranajit K Datta

Harry M Laska

Douglas M Rutan

Todd R Springer

Robert L Bateman, Jr

Charles N Stewart

Lisa Mason Ward

Laverne E Walsh

Csaba F Rappensberger

H Michael Laska

Gerald L Bucher

Christopher H Welker

J Robert Woodward

David J Marks

Changlong Ning

Gary L Price

Cynthia A Secen

Katherine L McGinnis

Jeannine A Woyansky

An arc tube for a ceramic metal halide lamp includes a hollow first body member () that is tapered along a majority of its length to aid in removing the molded component from a pin during assembly. An open end () of the first body member has a constant diameter () allowing it to be joined to a constant diameter portion () of the second body member or end cap (). The mating constant diameter portions ensure that the hollow first body member can be monolithically joined with the end cap with a reduced level of seal voids.

Injection molded ceramic metal halide arc tube having non-tapered end and method of forming same

A ceramic discharge chamber for a lamp, according to an exemplary embodiment of the invention, comprises a first member which includes a leg portion and a transition portion, wherein the leg portion and the transition portion are integrally formed as one piece from a ceramic material, and a second member which includes a body portion, wherein the body portion is bonded to the transition portion of the first member. The ceramic discharge chamber can be formed by injection molding a ceramic material to form the first member, the first member forming a first portion of the ceramic discharge chamber; and bonding the first member to a second member which forms a second portion of the ceramic discharge chamber.

Ceramic discharge chamber for a discharge lamp

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.

A process for making an arc tube comprises the steps of sintering an arc tube composition to form the arc tube; annealing the arc tube in a vacuum; and sealing the arc tube with at least one electrode. Preferably, the arc tube annealed according to the present process is a ceramic arc tube. The annealing of the arc tubes in a vacuum preferably occurs at a temperature of between about 1000&deg; C. and 1500&deg; C.

Ceramic arc tube by annealing

A ceramic discharge chamber for a lamp, according to an exemplary embodiment of the invention, comprises a first member which includes a leg portion and a transition portion, wherein the leg portion and the transition portion are integrally formed as one piece from a ceramic material, and a second member which includes a body portion, wherein the body portion is bonded to the transition portion of the first member. The ceramic discharge chamber can be formed by injection molding a ceramic material to form the first member, the first member forming a first portion of the ceramic discharge chamber; and bonding the first member to a second member which forms a second portion of the ceramic discharge chamber. The members which form the ceramic discharge chamber can greatly facilitate assembly of the discharge chamber, because the discharge chamber can be constructed with only one or two bonds between the members. The reduction in the number of bonds has the advantages of expediting assembly of the discharge chamber, reducing the number of potential bond defects during manufacturing, and reducing the possibility of breakage of the discharge chamber at a bond region during handling. One or more of the members may also include a radially directed flange which allows the members to be precisely aligned during assembly to improve the quality of the lamp.

A high transmittance polycrystalline alumina arc tube for a metal halide discharge lamp is formed by treating an alumina arc tube material having a few percent of closed porosity in a two step process, which provides a high-transmittance arc tube. An initially porous arc tube is formed by extruding or die pressing individual components of the tube from a mixture which includes powdered alumina, assembling the components into an arc tube body, and then partially sintering the components to seal them together. The two step process includes hot isostatic pressing of the partially sintered arc tube and then chemically polishing the surface of the tube. The first, pressing step involves heating the alumina arc tube in an inert atmosphere, such as argon, at a temperature of 1600 to 1900&deg; C. and a pressure of about 700 to 2100 kg/sq.cm. for from about one to three hours. This reduces porosity in the crystalline structure. In the second step, the surface of the tube is immersed in a flux comprising a molten alkali metal borate at moderately elevated temperatures, or coated with a flux material which is heated to form the flux, to remove surface imperfections. The finished arc tube has transmittance values which approach those of single crystal sapphire arc tubes.

High transmittance alumina for ceramic metal halide lamps

An electric lamp ( ) including a sealed light-transmissive lamp envelope ( ) having an interior space, a base fixed to the outer envelope ( ), a non-insulated main conductor wire ( ) within the outer envelope and connected to the base ( ) at one end, a light source ( ) capable of generating light within the outer envelope ( ), a shroud ( ) surrounding the light source ( ) and mounted adjacent the non-insulated main conductor wire ( ), and a first center support. The light source ( ) has first and second ends. The first end is electrically coupled to the non-insulated main conductor wire ( ), and the second end is coupled to a stem lead ( ). The first center support ( ) supports the shroud ( ) and the light source ( ) and mechanically couples the shroud ( ) and the light source ( ) to the non-insulated main conductor wire ( ).

Shrouded electric lamp having functionally distinguishable center supports

A method of making a component of a ceramic discharge chamber comprising the steps of forming a ceramic composition including an aluminum powder, a binder and a grain growth inhibitor. The alumina powder has a tap density greater than 1.0 gram per cc. The ceramic composition is then die pressed to form a component preform. Next, the component preform is heated to remove at least a substantial portion of the binder.

Die pressing arctube bodies

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

A method of making a ceramic discharge chamber comprising forming a plurality of preform chambers by assembling at least two ceramic components. The preform chambers are axially aligned within a tube, comprised of an alumina cermet. The tube containing the preform chambers is then fired at a temperature of at least 900&deg; C.

Cermet sintering of ceramic discharge chambers

An arc discharge lamp comprising an arc tube including a starting aid is provided. The starting aid comprises at least one prealloyed powder bound to the surface of the arc tube.

Applying prealloyed powders as conducting members to arc tubes

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

An arc discharge lamp, such as a metal halide arc discharge lamp, has an extended life by reducing loss of the metallic portion of the fill. At least one component of the fill reacts with fused silica in the arc tube or diffuses through the arc tube walls. The fill will generally comprise a sodium halide, at least one additional metal halide, and an inert starting gas. A borosilicate glaze which is vitreous and light-transmissive is provided on the wall of the arc tube. The borosilicate glaze is comprised of a borosilicate glass containing at least one metal oxide selected from aluminum, scandium, yttrium, and the rare earth elements. The borosilicate glaze may further contain additional rare earth elements or transition metals to alter the light or energy emission of the lamp by absorbing select wave lengths. For instance, titanium, ceria, cobalt, chromium, iron or neodymium, or combinations of the foregoing, may be added.

High temperature glaze for metal halide arctubes

A process for converting a polycrystalline ceramic material to a single crystal material includes the steps of doping at least a first portion of the polycrystalline ceramic material with a conversion-enhancing dopant having a &plus;6 valence state in the unfired ceramic material and heating the polycrystalline ceramic material to convert at least a second portion of the polycrystalline ceramic material to a single crystal ceramic material. Preferably, the ceramic material is alumina and the conversion-enhancing dopant is molybdenum or tungsten.

Conversion of polycrystalline alumina to single crystal sapphire using molybdenum doping

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Mentor, OH, United States of America

Curtis E Scott