Abstract: A compact halogen-cycle type incandescent lamp is provided with an envelope that is composed of a selected hard glass (a borosilicate or an aluminosilicate type glass for example) and then dosed with an amount of bromine which is correlated with the glass composition in such a manner that it counteracts the deleterious release of water-vapor forming constituents by the glass envelope when the lamp is energized and the glass is hot. The halogen-cycle lamp is especially adapted for use as the concentrated light source in a general service type lamp or a sealed-beam headlamp and, when so employed, has a fill gas pressure that is so correlated with the gas pressure of the non-oxidizing atmosphere in the outer envelope that the total gas pressure does not exceed 1,000 Torr and the envelope of the halogen-cycle lamp operates at a temperature which is sufficient to reliably sustain the halogen cycle but is below the softening temperature of the particular hard glass from which the halogen lamp envelope is made.

Abstract: The inner ends of the lead-in wires of an electric incandescent lamp are serrated and welded to uncoiled leg portions of the tungsten filament so that the members are fused to one another at a plurality of spaced points or locations and provide strong reliable electrical junctures. The filament leg portions are in bridging relationship with the serrations on the ends of the lead wires and form high-resistance areas of contact during the welding operation that permits high-quality welds to be made efficiently without the use of a flux material, even in halogen-cycle type lamps that require the welding of molybdenum lead wires to a tungsten filament.

Abstract: A selected part of the envelope of a fabricated electric lamp is made light-reflecting by spraying it with a coating composition that contains aluminum flakes of such minute size that they inherently arrange themselves in planar relationship and form a specular film which provides a mirror-like reflector surface as the composition dries. A protective coating of a suitable heat-resistant material, such as silicone plastic, is then sprayed over the reflective film and cured. The protective coating can also contain aluminum particles in order to fill voids that may be left in the thin specular film and to make the latter more opaque.

Abstract: The reliability of a photoflash lamp which is fired by a high-voltage pulse is improved by fabricating the flash-ignition mount from a glass bead, a glass sleeve and a pair of lead-in wires that have inwardly-bent end portions which define a gap of precise length that is uniform from lamp to lamp. The sleeve and bead are fused together and around parts of the lead-in wires such that only the bent tips of the wires protrude beyond the end face of the bead. The gap is filled with primer material that is deposited on the end face of the bead and completely covers the lead wire tips. The fused glass sleeve encloses one of the lead-in wires below the bead and is embedded in the envelope seal, thus not only insuring that the mount assembly is properly positioned within the envelope but insulating one of the lead-in wires and preventing the filling of combustible metal strands from accidentally touching both lead-in wires and internally short-circuiting the unfired lamp.

Abstract: The planar multi-coil filament of a high-wattage halogen-cycle incandescent lamp is suspended within the envelope by a mount assembly having support rods that are fastened to the lead-in conductors, the ends of the filament and the insulating bridge members by mechanical means rather than metal-to-metal welds. The mechanical junctures are effected by providing a coiled portion on one of the components and then crimping or hot-clamping it around the inserted part of the other component. The expense and quality control problems encountered with tungsten-to-tungsten and molybdenum-to-tungsten welds in the prior art halogen-cycle lamps are thus eliminated. Lamp cost is further reduced by fabricating the envelope from a selected hard glass and, in the case of lamps having large planar filaments, distortion of the filament coiled sections is prevented by modifying the mount structure to provide a "floating bridge" action.

Abstract: An electric lamp having a sealed-beam or single-ended domed type envelope that contains a tungsten filament and a halogen additive is provided with a specular coating of gold, palladium, platinum, or rhodium on a selected portion of its inner surface. The metal coating serves as a non-reactive interior reflector which does not getter the halogen additive or contaminate the lamp atmosphere and thus optically controls the light output of the lamp without interfering with the halogen-tungsten regenerative cycle. In an alternative embodiment, the outer surface of the envelope is properly contoured (to provide a parabolic surface, for example) and then coated with a thin layer of aluminum, silver, nickel or chromium which serves as an exterior reflector. The regenerative tungsten-halogen cycle is thus achieved in a reflector type lamp without the separate halogen lamp component heretofore required in such lamps.

Abstract: A selected part of the envelope of a fabricated electric lamp is made light-reflecting by spraying it with a coating composition that contains aluminum flakes of such minute size that they inherently arrange themselves in planar relationship and form a specular film as the composition dries. A protective coating of a suitable heat-resistant material, such as silicone plastic, is then sprayed over the reflective film and cured. The protective coating can also contain aluminum particles in order to fill voids that may be left in the thin specular film and to make the latter more opaque.