Abstract: An arc robe for a discharge lamp comprises a hollow body containing an arc generating and sustaining medium. The body has oppositely disposed ends each containing an electrode sealed therein by a seal associated with the ends. At least one of the ends has a heat shield thereabout, the heat shield comprising a metal foil wrapped about the end and being fixed to the seal. The metal foil is preferably nickel having a thickness of from about 0.0254 mm to 0.127 mm.

Abstract: An electric lamp includes a sealed lamp envelope including a dome region having an inward projection and a neck region sealed to a lamp stem. A lamp subassembly is located within the lamp envelope and includes an arc tube for generating light when electrical energy is applied thereto. A generally cylindrical, light-transmissive shroud is disposed about the arc tube. A frame includes a single support rod extends between the dome and neck regions of the lamp envelope along one side only of the subassembly, and a dome end of the frame engages the inward projection of the lamp envelope. A mounting structure is provided for attaching the arc tube and shroud to the frame. A bulb spacer is provided having first and second segments bearing against an inside surface of the lamp envelope in the neck region for positioning the frame relative to the lamp envelope, and also having a third segment joining the first and second segments, the third segment being spaced away from the inside surface of the lamp envelope.

Abstract: A bi-metallic switch element 10 has a contact wire 26 attached thereto by means of a plurality of crimps. A first crimp 28 applied at a first pressure fixes the contact wire to the element and a second crimp 30, formed at a lesser, more controlled pressure aligns the contact wire in a predetermined location.

Abstract: A double-enveloped lamp having a shield surrounding a light-source capsule within a thick-walled outer envelope so that the lamp may be safely operated without necessity of a protective fixture. In the rare event of a burst of the light-source capsule, the shield absorbs and dissipates a portion of the burst energy sufficient to permit the thick-walled outer envelope to remain intact and contain shards and other internal parts within the lamp. In alternate embodiments, the shield may be reinforced, such as with a wire mesh, or the outer envelope may be reinforced, such as with a polymer coating, or both. A thin-walled capsule may be employed in combination with a shield and thick outer envelope. A lamp in accordance with the invention provides the unexpected benefits of improved luminous efficacy and better color rendering characteristics, since the presence of an optimally positioned shield causes the operation of the light-source capsule to be more nearly isothermal.

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: A high-pressure metal halide arc discharge lamp having an arc tube with a pair of main electrodes disposed within the tube at opposite ends and a starting electrode located adjacent one of the main electrodes. A tubular sleeve of insulating material, such as quartz, is disposed about the starting electrode, which is recessed within the sleeve but exposed through the open end thereof to the interior atmosphere of the arc tube. Since the starting electrode does not project beyond the open end of the sleeve, conduction between that electrode and the adjacent main electrode is minimized or prevented during normal lamp operation, thereby minimizing or preventing electrolysis.