Abstract: The neck of a typical PAR lamp tends to focus the light issued in the neck or heel of the lamp back onto the lamp seals. The focused lost light then tends to overheat the seal and shorten lamp life. A practical solution is to intercept this lost light with a light absorbing layer. The light is then converted to heat in the layer. The heat is then re-radiated in an unfocused fashion with only a small portion of it redirected to the seal area. The interception layer may be formed as a black top coating on the neck interior or the neck exterior if the reflector is otherwise light transmissive. Alternatively, the neck may be formed from a translucent or opaque material that then converts the light into heat in the body of the reflector wall. The neck is then specifically not metallized so as to reflect light from the internal neck surface back to the lamp seal.

Abstract: The neck of a typical PAR lamp tends to focus the light issued in the neck or heel of the lamp back onto the lamp seals. The focused lost light then tends to overheat the seal and shorten lamp life. A practical solution is to intercept this lost light with a light absorbing layer. The light is then converted to heat in the layer. The heat is then re-radiated in an unfocused fashion with only a small portion of it redirected to the seal area. The interception layer may be formed as a black top coating on the neck interior or the neck exterior if the reflector is otherwise light transmissive. Alternatively, the neck may be formed from a translucent or opaque material that then converts the light into heat in the body of the reflector wall. The neck is then specifically not metallized so as to reflect light from the internal neck surface back to the lamp seal.

Abstract: Rare-earth halides are shown to be a replacement for scandium halides in mercury-free discharge arc lamps if modifications are made to the prior art lamp design and operating temperatures. The inventive chemical compositions of the discharge medium provide enhanced color rendition index values. In addition, it has been unexpectedly determined that during the operation of the discharge lamps, the rare earth iodides do not react significantly with the fused silica arc tube. Equally as significant, any free iodine, which is so formed, has minimal impact on the efficacy of the lamp compared to the conventional scandium iodide lamps. Therefore, the rare earth iodide-containing lamps provide longer lifetime with superior illumination characteristics than conventional discharge lamps.

Abstract: An arc tube for a high pressure metal vapor discharge lamp is provided. The arc tube of the present invention comprises a tubular ceramic envelope; a chemical fill within said envelope; a seal button at each end of said envelope; said seal button having an aperture therethrough for receiving a feedthrough member; a feedthrough member having an electrode projecting therefrom passing through said seal button aperture and being oriented such that the electrode projects into said tubular ceramic envelope, said feedthrough member being sealed into said seal button by means of a fritless seal between said seal button and said feedthrough; and sealing frit material sealing said seal buttons into the ends of said tubular ceramic envelope. A method for fabricating the above-described arc tube and high pressure metal vapor discharge lamp including the above-described arc tube is also provided.

Abstract: An arc tube for a high pressure metal vapor discharge lamp is provided. The arc tube of the present invention comprises a tubular ceramic envelope; a chemical fill within said envelope; a seal button at each end of said envelope; said seal button having an aperture therethrough for receiving a feedthrough member; a feedthrough member having an electrode projecting therefrom passing through said seal button aperture and being oriented such that the electrode projects into said tubular ceramic envelope, said feedthrough member being sealed into said seal button by means of a fritless seal between said seal button and said feedthrough; and sealing frit material sealing said seal buttons into the ends of said tubular ceramic envelope. A method for fabricating the above-described arc tube and high pressure metal vapor discharge lamp including the above-described arc tube is also provided.

Abstract: An emissive material for use in a vapor discharge device including reacted Ba.sub.x Sr.sub.1-x Y.sub.2 O.sub.4 wherein X satisfies the following: 1>X.gtoreq.0. A vapor discharge device is provided having an arc tube which includes electrodes therein coated with such emissive material.

Abstract: An arc tube including a tubular ceramic envelope; a chemical fill within the envelope; a seal button at each end of the envelope, the seal button having an aperture therethrough for receiving a feedthrough member; a feedthrough member having an electrode projecting therefrom passing through the seal button aperture and being oriented such that the electrode projects into the tubular ceramic envelope; frit material sealing the seal buttons into the ends of the envelope and the feedthrough members into the seal buttons; and means for interrupting the seal interface between the feedthrough member and the frit material around the total circumference of at least a portion of the feedthrough member. In a preferred embodiment of the present invention, the means for interrupting the seal interface includes a coating disposed around the periphery, or circumference, of the feedthrough member.

Abstract: A method for improving the density and other properties of caustic magnesia and sintered periclase. To improve the density of sintered periclase, acid or acid salt is admixed with magnesium hydroxide, followed by caustic-firing, pressing and high-firing. If desired, the admixture is dried before caustic-firing. Alternatively, the step of caustic-firing may be omitted. To improve the density and compactability of caustic magnesia, acid or acid salt is admixed with magnesium hydroxide, followed by caustic-firing. If desired, the admixture is dried before caustic-firing. Preferably, acetic acid is used.