Abstract: A metal halide arc discharge lamp rated for not more than 150 watts and 100 volts and which can be operated in either a horizontal or vertical position without a significant change in color temperature or lumen output has an ellipsoidal arc chamber mounted within a nitrogen-containing outer envelope. The arc chamber contains a pair of electrodes, mercury and sodium and scandium iodides and is coated at each end with a heat reflective coating. The chamber aspect ratio, electrode insertion length, metal halide density, coating length and wall loading are defined within narrow ranges.

Abstract: This lamp comprises an envelope of vitreous light-transmitting material enclosing an internal space, light-generating means within said space, and conductive lead structure projecting into said space and comprising inner and outer lead members and a foil member connected between said lead members. A first portion of the envelope surrounds the foil member and is sealed thereto, and a second portion of the envelope is located inwardly of the first portion. A tubular bead of vitreous material is provided about the inner lead member. This bead fits within the second envelope portion, is joined thereto, and supports the inner lead member in a precise predetermined portion within the envelope. The inner lead member projects inwardly beyond the bead and provides support for the light-generating means.

Abstract: Fused quartz containing europium oxide, titanium dioxide and cerium oxide has been found to be effective for absorbing UV radiation while transmitting visible light radiation. Uses for this material include lamp envelopes and shrouds for halogen-incandescent lamps and metal halide arc discharge lamps which emit both UV and visible light radiation.

Abstract: An arc tube of fused silica for a metal halide arc discharge lamp including a fill for the arc tube comprised of a sodium halide, at least one additional metal halide, and an inert starting gas, the arc tube including a tube of fused silica having an inner wall defining an arc chamber, the inner wall of the tube having provided thereon a metal silicate coating which is vitreous and light-transmissive, and which is comprised of a silicate of at least one metal selected from the group consisting essentially of scandium, yttrium, and a rare earth element, and preferably which is the same metal as that of the at least one additional metal halide. Protection of the fused silica arc tube with the metal silicate coating reduces loss of the metallic portion of the fill by diffusion or reaction and corresponding buildup of free halogen in the arc tube.

Abstract: The invention relates to an electrode-inlead assembly for electrical lamps which comprises a lead-in-wire connected to a foil made of refractory metal and the foil is connected to a shank made of refractory metal and supporting the electrode.The object of the invention is, that the shank is made of two parallel rods which are joined by their one end portions, and their opposite end portions are welded to the foil, so that the foil is sandwiched between the rods.

Abstract: A high pressure discharge lamp with a thermally improved anode, as well as a method of making such a lamp, are disclosed. The lamp includes a refractory arc tube with a hermetically sealed arc chamber, a fill in the arc chamber for facilitating light generation, and an anode and a cathode extending into the hermetically sealed arc chamber and being spaced apart from each other. The anode comprises a shank of refractory metal, a cylindrically shaped refractory metal sleeve on a portion of the shank, and an end proximally facing the cathode. The anode end comprises a substantially solid mass of refractory metal, and is integrally joined to both the shank and the metal sleeve to facilitate heat flow from the anode end to the shank and sleeve. The anode end preferably is generally shaped as a hemisphere facing the cathode. The refractory metal sleeve is preferably one or more layers of a helically wound refractory metal wire having an outer diameter more than twice a diameter of the shank.

Abstract: This headlamp comprises a reflector and a discharge lamp comprising an inner envelope having a longitudinal axis coinciding with the optical axis of the reflector. The inner envelope includes a bulbous portion, a front leg extending along the optical axis from the bulbous portion toward the front of the headlamp, and a back leg extending along the optical axis from the bulbous portion toward the reflector. The discharge lamp further comprises a tubular shroud comprising a first hollow portion surrounding the front leg of the inner envelope, a second hollow portion surrounding the back leg of the inner envelope, and a bulbous portion between the two hollow portions. The front leg is provided with a large-diameter integral enlargement (referred to herein as a "large-diameter maria"), and the shroud is joined to the front leg by a maria seal located at the outer periphery of this maria.

Abstract: A high brightness discharge light source includes an arctube having an arc chamber formed therein and in which is disposed a fill of gas energizable to a discharge condition. At least two electrodes extend into the arc chamber and are separated by an arc gap of between 2 and 3.5 mm. The dose of mercury disposed in the arc chamber and various arc tube dimensions are selected so as to achieve a balance between three constraints including operating voltage thereby defining lamp efficacy, convective stability and structural integrity of the discharge lamp. A balance between arc gap, arc chamber diameter, wall thickness and the mercury density of the lamp yield a discharge lamp which achieves a light output on the order of 50,000 lumens per square centimeter.

Abstract: Fused quartz containing both titanium dioxide and cerium oxide as UV absorbing dopants has been found to be particularly effective for lamp envelopes for high temperature lamps such as halogen-incandescent lamps and metal halide arc discharge lamps which emit both UV and visible light radiation. The codoped quartz transmits visible radiation and absorbs a substantial portion of the emitted UV radiation. The UV absorption is far superior at temperatures above 500.degree. C. and the codoped quartz does not react with the fill within.