Abstract: A low wattage single-ended metal halide arc discharge lamp has an isothermal arc chamber with an outer diameter (t) substantially equal to the product of a first constant and the lamp wattage plus a second constant; a fill gas and a pair of electrical conductors sealed into and passing through one end of the arc chamber to provide a pair of electrodes therein having a spacing therebetween of a distance to provide a substantially uniform current for lamps in the range of about 35 to 150 watts.

Abstract: A low wattage single-ended metal halide arc discharge lamp has an isothermal arc chamber with an outer diameter (t) substantially equal to the product of a first constant and the lamp wattage plus a second constant; a fill gas and a pair of electrical conductors sealed into and passing through one end of the arc chamber to provide a pair of electrodes therein having a spacing therebetween of about a distance to provide a substantially uniform current for lamps in the range of about 35 to 150 watts.

Abstract: A single-ended metal halide discharge lamp including a fused silica elliptical-shaped envelope which is filled with a metal halide dosed high pressure mercury fill and wherein a pair of electrodes each having a metal rod with a ball on the end thereof are sealed whereby isothermal operation of the elliptical-shaped envelope is effected. A manufacturing process is also provided wherein an elliptical-shaped envelope is formed, a pair of electrodes having metal rods with a ball on the end thereof are sealed into one end of the envelope, and the envelope is filled with a metal halide dosed high pressure mercury fill.

Abstract: A single-ended metal halide discharge lamp includes a plurality of fill gases selected to provide essentially white light at a plurality of distances from a pair of spaced electrodes and to combine the radiation from the multiple distances to provide white light with minimal color separation from the discharge lamp. Also, a method for providing spectral uniformity from a discharge lamp is provided wherein the emitted color and distance from a longitudinal axis provided by a plurality of fill gases is observed, fill gases are selected to provide white light emission at a plurality of distances from the longitudinal axis and the selected fill gases are combined to provide white light with minimal color separation from the discharge lamp.

Abstract: A single-ended metal halide discharge lamp includes a plurality of fill gases selected to provide essentially white light at a plurality of distances from a pair of spaced electrodes and to combine the radiation from the multiple distances to provide white light with minimal color separation from the discharge lamp. Also, a method for providing spectral uniformity from a discharge lamp is provided wherein the emitted color and distance from a longitudinal axis provided by a plurality of fill gases is observed, fill gases are selected to provide white light emission at a plurality of distances from the longitudinal axis and the selected fill gases are combined to provide white light with minimal color separation from the discharge lamp.

Abstract: A miniature, low-wattage, discharge lamp operable on direct current employs substantially parallel electrodes sealed in a single press seal. The electrodes are configured to provide an arc which is substantially parallel to the longitudinal axis of the lamp with the cathode being substantially longer than the anode. Heat generated at the anode is dissipated through the seal to the cathode allowing the cathode to operate hot enough to be stable. The chemical fill for the lamp employs a mol ratio of thorium to cesium to permit good light output and good color rendition.

Abstract: A D.C. operable, miniature, low-wattage, single ended, arc discharge lamp. The cathode electrode includes electrical field modifying means to insure that the arc strikes between the electrode tips. During high pressure (.about.10 atm) operation electrode heating of the anode is dominated by electron bombardment, which creates substantially higher heat at the anode tip than at the cathode tip (the cathode being heated by ion bombardment and cooled by thermionic electron emission). Heat conducted down the anode electrode is dissipated in the single press and contributes to the heat conduction in the closely adjacent cathode electrode thereby reducing the net heat loss therein and helping to maintain the desired cathode temperature.

Abstract: A high intensity discharge lamp includes arc extinguishing means functional when the outer envelope of the lamp fails. The extinguishing means comprises a pressure sensing diaphragm and a terminal which will melt back when an arc is drawn therebetween. The extinguishing means operates within a time interval of several milli-seconds.

Abstract: A high intensity discharge lamp includes, within the outer envelope, a strip of niobium foil serially connected between a power source and one of the electrodes of the arc tube of the lamp. The foil is not a power consuming element but will oxidize and open the circuit, thus extinguishing the lamp, in the event the outer envelope is ruptured.

Abstract: A lamp operating circuit comprising a DC power source, an inverter including step-up transformer inductance windings and a controlled transistor switch connected across the output of the DC source, and a high frequency oscillator coupled to the transistor switch for operating the same at predetermined intervals. A low wattage HID lamp is connected across the inverter through a ballast capacitor series connected to one terminal of the lamp and a ballast inductance coupled in series with the other lamp terminal. The ballast inductance and ballast capacitor are selected to resonate sinusoidally at a frequency having a half period coinciding with the on-time of the transistor.

Abstract: A single ended, low-wattage, high pressure, metal vapor discharge lamp includes first and second main electrodes and an auxiliary electrode resistively coupled to one of the main electrodes. The lamp provides a glow region remote from the main arc region and keeps wall blackening confined to areas remote from the main arc region. The lamp starts easier and minimizes detrimental glow time.

Abstract: A low wattage metal halide arc discharge lamp has a press seal at one end thereof with two main electrodes sealed therein. The ratio of the distance from an electrode tip to the nearest arc tube wall over the arc length is greater than 0.4.

Abstract: A high intensity discharge device operable in any orientation employs electrodes whose major portions are parallel and whose minor portions converge toward each other. The converging minor portions can be loops of electrode material.

Abstract: A single ended, short arc, low wattage, high pressure, metal vapor discharge lamp is electrode stabilized and employs arc constrictors selected from the group of lanthanides, actinides and thorium to provide a brightness of 175,000 cd/in.sup.2 when operated at 75 watts.

Abstract: A single ended metal halide arc discharge lamp contains mercury, sodium halide, scandium, scandium halide and a starting gas. The molar ratio of sodium halide to scandium halide is between about 5 to 8 in order to obtain optimum luminous efficacy.