Abstract: A high-pressure sodium lamp in which the inner diameter of an arc envelope is largest at the midpoint between the ends thereof and the inner and outer diameters thereof in the vicinity of the ends at which are air-tightly fitted electrodes and their associated parts are reduced gradually relative to the inner diameter of the midpoint thereof. When the arc envelope is turned on, the following conditions are satisfied:T.sub.e .gtoreq.0.85 T.sub.c and1020.degree. C..ltoreq.T.sub.c .ltoreq.1200.degree. C.where T.sub.e is the wall temperature at the leading or inner tip of each of the electrodes andT.sub.c is the wall temperature at the midpoint of the arc envelope.

Abstract: The invention relates to lamps having a glass lamp vessel (1) and to a glass suitable therefor. The relevant glass is adequately resistant to attack by electrons, is resistant to atmospheric influences and is properly workable in a gas flame. This glass contains 44-60 mole % silicon oxide; 0-7.5 mole % boron oxide; 0-6 mole % zirconium oxide; 0-7.5 mole % aluminium oxide; 5-20 mole % calcium oxide; 12.5-25 mole % barium oxide; 0-15 mole % magnesium oxide; 0-10 mole % strontium oxide; 2-8 mole % sodium oxide. The sum of the alkaline earth metals is 25-42.5 mole %.No discoloration occurs in sodium vapor discharge lamps when the lamp vessel has been made of this glass.

Abstract: A lamp seal glass is described suitable for direct hermetic sealing to molybdenum which consists essentially of oxides in approximate percent by weight 52-60 SiO.sub.2, 11-17 Al.sub.2 O.sub.3, 11-16 BaO, 8-12 CaO, and 3-7 B.sub.2 O.sub.3, along with minor amounts of incidental impurities, residual fluxes and refining agents, said glass having a liquidus temperature no greater than about 1170.degree. C., a softening point in the approximate range 900.degree.-930.degree. C., a strain point in the approximate range 650.degree.-680.degree. C., a working point in the approximate range 1180.degree.-1240.degree. C., and an average coefficient of linear thermal expansion in the 0.degree.-300.degree. C. temperature range between about 45-50.times.10.sup.-7 cm/cm/.degree.C. The glass composition enables improved manufacture of incandescent lamps operating in the moderately elevated temperature range 500.degree.-650.degree. C., especially regenerative cycle halogen lamps.

Abstract: An arc tube for a high-pressure sodium (HPS) discharge lamp having an extended seal path to reduce leakage therethrough. The extended seal path is provided by a monolithic arc tube body having circular apertures in the ends thereof of a substantially smaller diameter than the diameter of the arc tube body and a skirted end cap having refractory metal tubulation extending centrally therethrough mounted on each end of the arc tube body. A glassy sealing frit is interposed between the entire interior surface of the end cap and that portion of the refractory metal tubulation extending through the circular aperture in the arc tube ends.

Abstract: An incandescent lamp of the tungsten halogen type is disclosed which includes the tipped-off residue of an exhaust tube formed with a high temperature aluminosilicate glass comprising in approximate weight percent 56-63 SiO.sub.2, 13-17 Al.sub.2 O.sub.3, 19-24 BaO, 1-4.5 CaO, and 0-3 R.sub.2 O wherein R is an alkali metal ion, along with minor amounts of incidental impurities, residual fluxes and refining agents such that the aggregate BaO and CaO content lies within the approximate range 21-26 weight percent in order to eliminate need for the refractory metal spiral being contained within said exhaust tube in order to keep said exhaust tube open while the lamp lead-in wires are being hermetically sealed in the lamp envelope. The same glass composition can also be employed to form the entire lamp glass envelope along with the exhaust tube portion thereof with comparable results.