Abstract: A method of making a fritless seal in a ceramic arc tube body comprises the steps of: (a) inserting a feedthrough into an opening in a ceramic arc tube body, the feedthrough being comprised of niobium or a niobium alloy; (b) heating the arc tube body to a first temperature in an inert gas to at least partially sinter the arc tube body, the inert gas being selected from the group of argon, neon, krypton, xenon and mixtures thereof; and (c) further sintering the arc tube body by heating to a second temperature in a hydrogen atmosphere to form a hermetic seal between the feedthrough and the ceramic arc tube body, wherein the second temperature is higher than the first temperature.

Abstract: A high intensity discharge lamp (10) has an envelope (12) having a base end (12a), a middle portion (12b) and domed end (12c) arrayed along an envelope longitudinal axis (14). Two spaced apart electrical lead-ins (34, 36) are sealed in the base end (12a) and extend into the envelope (12). A substantially U-shaped frame (38) is within the envelope (12) and the U-shaped frame comprises glass tubing 26a. A light source (16) has an arc discharge capsule (16b) positioned within the frame (38) and a containment vessel (18) is spaced from and surrounds the arc discharge capsule 16b. The containment vessel (18) comprises a transparent structure (19) attached to the frame (38) and formed to provide multiple, independent, localized fractures capable of absorbing the given kinetic energy possessed by the shards.

Abstract: A ceramic metal halide lamp is provided wherein the ceramic discharge vessel is comprised of dysprosium oxide. The lamp has a warm-up time that is less than about 50%, and preferably less than about one-third, of the warm-up time of a similarly constructed and operated lamp having a ceramic discharge vessel made of polycrystalline aluminum oxide.

Abstract: A method of operating an arc discharge lamp and a lamp in which a light transmissive envelope encloses electrode tips, a salt and a fill that includes iodine, and in which after turning the lamp off, a first part of the light transmissive envelope is locally cooled relative to other parts of the light transmissive envelope to provide a condensation site for the iodine that is spaced from the electrode tips, the first part of the light transmissive envelope being where a salt reservoir forms and where the salt is cooled by the local cooling. The local cooling may be provided by an indentation in an outer sleeve around the light transmissive envelope, where the indentation contacts the first part to provide a heat sink.

Abstract: A ceramic discharge vessel is provided wherein the discharge vessel has a ceramic body and at least one expanded reaction-bonded aluminum oxide member hermetically sealed to the ceramic body. The method of making the discharge vessel includes (a) forming a ceramic body; (b) forming a reaction-bonded aluminum oxide member in a green state by compacting a mixture of aluminum metal and aluminum oxide powders; (c) assembling the ceramic body and the reaction-bonded aluminum oxide member in the green state to form an assembly; and (d) reaction sintering the assembly to cause the reaction-bonded aluminum oxide member to expand and form a hermetic seal with the ceramic body.

Abstract: An arc discharge vehicle lamp (10) for nebulous weather comprising a body (12) defining a chamber (14) having a volume of between 0.025 to 0.035 cc and including spaced apart electrodes (16, 18) having an arc gap (20) of between 2 and 6 mm; and an arc generating and sustaining medium (21) in the chamber for developing light having a color temperature between 1800K to 2800K during operation of the lamp. A preferred arc gap is 4.2 mm. The electrodes (16 and 18) are preferably fashioned with three parts; a niobium sealing region, an intermediate region of molybdenum and a tungsten region, which protrudes into the discharge chamber.

Abstract: A ceramic discharge vessel is provided wherein the vessel comprises a hollow body for enclosing a discharge and the hollow body is made of a polycrystalline dysprosium oxide containing a luminescent dopant that emits one or more visible light wavelengths when stimulated by radiation generated by the discharge. Preferably, the polycrystalline dysprosium oxide has been doped with one or more of europium, cerium, or terbium in an amount from about 0.1 to about 10 percent by weight on an oxide basis.

Abstract: The seal temperature of a reflector lamp having a ceramic metal halide light source is reduced by a light absorbing layer which is provided in a region of the outer jacket adjacent to the electrode seal. Light reflected within the neck cavity of the reflector lamp impinges on the light absorbing layer and is absorbed before it can reach the electrode seal which is at least partially located in the neck of the reflector. The heat from the absorbed light is conducted into the base of the lamp to be dissipated in the socket.

Abstract: Superior color stability in a miniature HID lamp can be achieved by reducing the size of the lamp, reducing the mercury concentration, reducing the salt concentration and increasing the heat to the lamp seal. In general the result concentrates the salts in the central, lower section of the lamp envelope and displaces them from the hot spot and electrode roots were deleterious chemical reactions can occur that are believed to subsequently reduce lamp performance.