Abstract: HID lamp has a U-enhancer connected between first and second leads for an arc tube. The UV-enhancer has a quartz envelope containing an electrode connected to the first lead, and is surrounded by a metal ring which is spaced from the envelope by a sleeve of borosilicate glass. The ring is capacitively coupled to the envelope and is electrically connected to the second lead, which may also support the sleeve.

Abstract: An electric discharge lamp has a discharge vessel including pair of opposing planar seals each having a pair of major faces and a pair of minor, side faces. A containment shield surrounds the discharge vessel and includes a glass sleeve and a helically coiled wire secured on the glass sleeve. The glass sleeve is pinched to bevelled ends of the minor, side faces of the seals only and substantially does not engage the major faces of the seal. The wire is fixed around the sleeve in an electrically floating manner, e.g. by clamping fit. With the sleeve secured to the discharge vessel, MH quality photometrics are obtained with a tubular body arc tube without an end coat. The construction of the lamp is simple and effective to protect the outer bulb from being damaged by an explosion of the discharge vessel, and to prevent sodium from disappearing from the discharge vessel as a result of photoemission.

Abstract: A high pressure discharge lamp having a discharge vessel with opposing end chambers includes discharge electrodes each consisting of an open elongate filament of refractory metal wire having a plurality of succesive coil turns extending transverse to the longitudinal axis of the discharge vessel. The filament electrodes are dimensioned so that the discharge arc which terminates thereon is sufficiently retracted into the end chamber of the discharge vessel so that the fill constituents condense on a region of the discharge vessel which is primarily axially between the filament electrodes. In a favorable embodiment, the lamp is a metal halide lamp in which the electrode and the discharge sustaining fill is free of thoria and its compounds.

Abstract: The invention is a method of assembling an electric lamp having a canted arc tube. The invention permits the lamp to be assembled using a standard bulged tube outer envelope having an elongate neck portion of the type normally used for lamps in which the arc tube is mounted coaxially with the envelope axis.In the inventive method, a stem assembly having a pair of rigid conductors extending therefrom is first sealed in the open end of the neck portion in a gas-tight manner. The envelope is severed around its circumference in the region where the neck portion merges into the bulbous portion of the envelope. After the two portions are separated, a frame holding the arc tube is welded to the rigid inductors of the stem assembly with the arc tube positioned at the desired angle with respect to the lamp defined by the elongate neck portion. The two envelope portions are then resealed in a gas-tight manner and a lamp cap secured to the neck portion.

Abstract: A lamp stem having integral glass structure for controlling gas flow into the lamp outer envelope of an electric lamp during back-fill. The lamp stem having a protrusion adjacent the stem press through which a conduit connected to the exhaust tube extends with a curved profile. The end portion of the conduit extends in the direction of the stem skirt and defines an acute angle with the exhaust tube. The end portion is angled for directing the gas flow during back-fill away from coated portions of the lamp envelope in which the stem is sealed. The conduit may have a cross-sectional area which increases in the direction of the gas flow so that the conduit functions as a gas diffuser for reducing the velocity of the gas in addition to directing the gas flow in a desired direction. In an alternative embodiment, the conduit terminates adjacent the stem press.