Abstract: This invention provides a method of welding an electric feedthrough assembly for an electric lamp. The feedthrough assembly comprises at least a plug and an electrode pin, each being formed from an electrically conductive refractory material, such as a molybdenum-titanium-nickel plug and a tungsten electrode pin. In a preferred embodiment of the invention, the electrode pin is inserted into a chuck of a drill press. The plug is placed on a rubber pad with the cavity in the plug aligned under the electrode pin. The electrode pin is rotated and pressed into the cavity with increasing pressure until the plug commences rotating on the rubber pad. Substantial heat is generated within the cavity by friction between the rotating electrode pin and the stationary surface of the plug within the cavity. As the pressure is increased on the electrode pin, intimate contact between the materials is attained.

Abstract: This invention provides an improved method of fabricating an arc tube, particularly a miniaturized arc tube having precise geometry and requiring exact electrode alignment. The improved method divides the press sealing operation into two distinct steps. In the first or preforming step, the ends of the arc tube are heated and preformed such that the ends have a substantially elliptical cross section; in the second or pressing step, the preformed ends are heated and pressed together to form completed press seals. During each step, the viscosity of the pliable glass remains low so that internal shearing forces are substantially reduced from those experienced in the prior art methods. As a result of the low viscosity during the pressing step, electrode misalignment, tearing of molybdenum foils, and deformation of the midsection of the arc tube are virtually eliminated. An electrode and a starting probe may be inserted with ease into a preformed end because of its flattened cross section.

Abstract: A method of manufacturing a low-pressure arc discharge lamp formed by interconnecting two or more parallel glass discharge tubes, each tube being sealed at one end. A hermetically sealed arc-containing channel between the two adjacent tubes is formed by heating opposing sections of the two tubes to soften a first and second site on each of the respective tubes. Then, one of the tubes is pressurized until a glass bubble forms from the softened site; the bubble is blown toward and onto the other tube about the softened site thereof. The pressure in the first tube is then released, and pressure is applied in the second tube to form a second glass bubble which fuses with the first glass bubble and bursts into the first tube thereby forming the sealed arc-containing channel between the two tubes. The technique may be applied to multiple tube assemblies by alternating the end of the tube at which the joint is formed.

Abstract: This invention provides a one-piece frame for electric lamps. The frame has a one-piece body formed by bending operations on a pre-cut or pre-stamped blank sheet of stiff electrically conductive material. In an alternate embodiment of the invention, the frame has a one-piece body formed by bending operations on a single strand of stiff electrically conductive wire. Lamps employing the invention will be easier and cheaper to construct, and they will be of comparable or improved quality compared with their counterparts under the prior art.

Abstract: A metal halide arc discharge lamp having a gaseous fill within the outer envelope and means for suppressing convection currents within such fill; and methods of operating and constructing such lamps. A light-transmissive sleeve or enclosure surrounding the arc tube laterally and about at least one end thereof is so shaped and mounted with respect to the arc tube as to insure that the Rayleigh Number, a quantitative measure of convection flow, in the atmosphere laterally surrounding the arc tube will be less than 5.times.10.sup.4 during operation of the lamp whereby excessive convective heat loss in such lamp will be effectively suppressed.

Abstract: A line-of-sight arched arc tube of an arc discharge lamp; e.g., a metal halide arc discharge lamp for horizontal operation having an arched upper wall to accommodate the bowing of the arc discharge during full temperature and pressure operation of the lamp and a lower wall of lesser curvature to accommodate the arc discharge during lamp start and warm-up. The curvature of the lower wall is such that there is a straight line-of-sight between the primary electrodes without being impeded by the lower wall of the arc tube and such that temperature profiles over the body of the arc tube are optimized during full temperature and pressure operation of the lamp.

Abstract: An arc-extinguishing ampul and a low-pressure arc discharge lamp, such as a fluorescent lamp, having such ampul on each electrode structure, the ampul comprising a thin-walled glass body enclosing an arc-extinguishing gas, at least one electrically conductive support wire, and a heat-conductive coating covering the outer surface of the ampul and portions of the support wire. Upon depletion of the electron-emissive coating on one electrode filament at the end of the useful life of the lamp, the arc discharge is attracted to the ampul by the support wire. The heat of the arc softens and melts the ampul to the point where the arc-extinguishing gas within the ampul escapes and renders the lamp inoperable without loss of the lamp's hermetic seal.