Abstract: A single-ended ceramic discharge lamp is described which has an integral optical surface such as a parabolic or elliptical reflector. The single-ended configuration eliminates the need for the mounting structures found in double-ended lamps that can interfere with the light emitted from the lamp, particularly in focused beam applications.

Abstract: An arc discharge lamp (10) has a lamp envelope (12) and an arc discharge vessel (14) mounted within the envelope (12). An arc centering structure (60) is positioned within the arc discharge vessel for substantially centering the arc. The centering structure (60) is preferably fixedly mounted within the arc discharge vessel (14) and preferably comprises a metal annulus (62) that incandesces during lamp operation and adds to the light output of the lamp. In a preferred embodiment, the lamp is suitable for vertical or horizontal operation.

Abstract: A single-ended ceramic discharge lamp is described which has an integral optical surface such as a parabolic or elliptical reflector. The single-ended configuration eliminates the need for the mounting structures found in double-ended lamps that can interfere with the light emitted from the lamp, particularly in focused beam applications.

Abstract: An arc discharge lamp (10) has a lamp envelope (12) and an arc discharge vessel (14) mounted within the envelope (12). An arc centering structure (60) is positioned within the arc discharge vessel for substantially centering the arc. The centering structure (60) is preferably fixedly mounted within the arc discharge vessel (14) and preferably comprises a metal annulus (62) that incandesces during lamp operation and adds to the light output of the lamp. In a preferred embodiment, the lamp is suitable for vertical or horizontal operation.

Abstract: A metal halide fill for a discharge lamp is provided that is comprised of mercury and a mixture of metal halide salts which includes magnesium iodide as a full or partial replacement for calcium iodide. The replacement of at least some of the calcium iodide improves the behavior of the molten salt condensate in the arc tube. In particular, the mixture of metal halide salts contains about 1 to about 50 mole percent sodium iodide, about 15 to about 50 mole percent of a rare earth iodide, about 10 to about 30 mole percent magnesium iodide, about 10 to about 25 mole percent of indium iodide, and about 0 to about 25 mole percent calcium iodide, wherein the sum of the amounts of calcium iodide and magnesium iodide in the mixture is from about 20 to about 45 mole percent.

Abstract: A ceramic arc tube for a metal halide discharge lamp is described wherein the lower end well of the arc tube has an internal barrier ridge which substantially prevents migration of the metal halide condensate into the central region of the discharge chamber during vertical operation. The use of the ridge reduces fluctuation in the color temperature of vertically operated lamps and improves efficacy.

Abstract: A thallium-free metal halide fill for ceramic metal halide lamps is provided wherein the fill comprises mercury, sodium iodide, an alkaline earth iodide selected from calcium iodide, strontium iodide, barium iodide, or combinations thereof, and a rare-earth iodide selected from cerium iodide, dysprosium iodide, holmium iodide, thulium iodide, or combinations thereof. In a preferred embodiment, the fill allows dimming of discharge lamps containing same to about 60% of rated power without substantially affecting the color of the emitted light.

Abstract: Arc tube (10) has a bulbous body (12) with a hollow center portion (14) and opposite ends (16, 18). Each of these ends has a cylindrical terminal-receiving section (20, 22) extending therefrom. The hollow center portion (14) has an internal length A and an internal diameter B that provides an aspect ratio of less than 5 and an outer surface area to inner surface area ratio, measured in square units, of less than 1.5. Electrodes (24) and (26) are hermetically sealed in the terminal-receiving sections (20, 22). The lamp uses less than 7 mgs of mercury. The low pressure operation allows the use of the arc tube in lamps without a shroud and the low mercury allow the lamp to pass TCLP requirement and be conventionally landfilled.

Abstract: Arc tube (10) has a bulbous body (12) with a hollow center portion (14) and opposite ends (16, 18). Each of these ends has a cylindrical terminal-receiving section (20, 22) extending therefrom. The hollow center portion (14) has an internal length A and an internal diameter B that provides an aspect ratio of less than 5 and an outer surface area to inner surface area ratio, measured in square units, of less than 1.5. Electrodes (24) and (26) are hermetically sealed in the terminal-receiving sections (20, 22). The lamp uses less than 7 mgs of mercury. The low pressure operation allows the use of the arc tube in lamps without a shroud and the low mercury allow the lamp to pass TCLP requirement and be conventionally landfilled.

Abstract: A ceramic arc tube for a metal halide discharge lamp is described wherein the lower end well of the arc tube has an internal barrier ridge which substantially prevents migration of the metal halide condensate into the central region of the discharge chamber during vertical operation. The use of the ridge reduces fluctuation in the color temperature of vertically operated lamps and improves efficacy.