Abstract: A metal halide arc discharge lamp includes a sealed light-transmissive outer jacket, a light-transmissive shroud located within the outer jacket and an arc tube assembly located within the shroud. The arc tube assembly includes an arc tube, electrodes mounted within the arc tube and a fill material for supporting an arc discharge. The electrodes have a spacing such that an electric field in a range of about 60 to 95 volts per centimeter is established between the electrodes. The diameter of the arc tube and the spacing of the electrodes are selected to provide an arc having an arc diameter to arc length ratio in a range of about 1.6 to 1.8. The fill material includes mercury, sodium iodide, scandium tri-iodide and a rare gas, and may include lithium iodide. The lamp exhibits a high color rendering index, high lumen output and high color temperature.

Abstract: An electric lamp assembly includes a sealed lamp envelope, a lamp capsule located within the lamp envelope, a cylindrical, light-transmissive shroud surrounding the lamp capsule, and a mounting arrangement for supporting the lamp capsule and the shroud within the lamp envelope. The mounting arrangement includes one or two supports rods parallel to the axis of the shroud and first and second clips for retaining the shroud and the lamp capsule. The clips prevent both axial and lateral movement of the shroud. The clips are attached to the support rods, typically by welding. In a preferred embodiment, a single clip at each end of the shroud retains both the shroud and the lamp capsule, and requires only a single weld to the support rod.

Abstract: An electric lamp assembly includes a sealed lamp envelope, a lamp capsule located within the lamp envelope, a cylindrical, light-transmissive shroud surrounding the lamp capsule, and a mounting arrangement for supporting the lamp capsule and the shroud within the lamp envelope. The mounting arrangement includes one or two supports rods parallel to the axis of the shroud and first and second clips for retaining the shroud and the lamp capsule. The clips prevent both axial and lateral movement of the shroud. The clips are attached to the support rods, typically by welding. In a preferred embodiment, a single clip at each end of the shroud retains both the shroud and the lamp capsule, and requires only a single weld to the support rod.

Abstract: An electric lamp assembly includes a sealed outer envelope, an arc discharge tube mounted within the outer envelope, a safety filament connected in series with the arc discharge tube for extinguishing the arc tube within a predetermined time after the outer envelope is broken, and an electrically-insulating sleeve disposed around the safety filament. The insulating sleeve suppresses emission of electrons from the safety filament and thereby prevents a reduction in frame potential which would increase sodium loss from the arc tube. The insulating sleeve includes openings which permit air to reach the safety filament when the outer envelope is broken. A mounting arrangement includes a pair of mounting tabs which provide electrical connections for the safety filament and which approximately centers the safety filament in the insulating sleeve.

Abstract: A method and an apparatus for position orienting a base assembly of a metal halide lamp is describe for maintaining the curved arc tube in the upward position when the lamp is inserted in a socket. Once the lamp has been fully assembled and sealed a locator structure is attached to the base shell in order to create a base assembly which will properly position the lamp when it is in the socket. The welding apparatus of the present invention resistance welds the locator structure onto the base shell once the locator structure has been aligned approximaely 90 degrees counterclockwise from the tip of the curved portion of the arc tube when viewed from the dome end of the lamp. The lamp resulting from the method and use of the apparatus will be more inexpensive and will not have the problems of a loose base or a cracked seal.

Abstract: A method and an apparatus for position orienting a base assembly of a metal halide lamp is describe for maintaining the curved arc tube in the upward position when the lamp is inserted in a socket. Once the lamp has been fully assembled and sealed a locator structure is attached to the base shell in order to create a base assembly which will properly position the lamp when it is in the socket. The welding apparatus of the present invention resistance welds the locator structure onto the base shell once the locator structure has been aligned approximately 90 degrees counterclockwise from the tip of the curved portion of the arc tube when viewed from the dome end of the lamp. The lamp resulting from the method and use of the apparatus will be more inexpensive and will not have the problems of a loose base or a cracked seal.

Abstract: A high intensity discharge lamp operable from an AC potential source includes an arc discharge tube having a pair of oppositely disposed main electrodes therein and an associated external starting electrode, all disposed within a sealed envelope having an affixed base with a circuit means including a negative potential blocking device coupling the starting electrode to the AC potential source.

Abstract: A high-pressure metal halide arc discharge lamp having an arc tube with a pair of main electrodes disposed within the tube at opposite ends and a starting electrode located adjacent one of the main electrodes. A tubular sleeve of insulating material, such as quartz, is disposed about the starting electrode, which is recessed within the sleeve but exposed through the open end thereof to the interior atmosphere of the arc tube. Since the starting electrode does not project beyond the open end of the sleeve, conduction between that electrode and the adjacent main electrode is minimized or prevented during normal lamp operation, thereby minimizing or preventing electrolysis.