Osram Sylvania Inc.

Gte Products Corporation

Nanu Brates

P Bruce Newell

Elliot F Wyner

Edward H Nortrup

Joseph Allen Olsen

James C Morris

Warren Paul Moskowitz

David Alan Goodman

David M Hrubowchak

George L Duggan

Zeya K Krasko

Richard Snellgrove

Philippe Verborg

A mercury-free metal halide arc lamp having an arc vessel of fused silica, an aspect ratio greater than 5, and containing a noble gas such as xenon, argon or krypton and a metal halide. In a preferred embodiment, the arc vessel has a diameter of 8 mm and a length of 80 mm, a fill of sodium/scandium iodides and a buffer gas of xenon.

Mercury-free metal halide arc lamps

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.

Chemical composition for mercury free metal halide lamp

A starting aid for a metal halide discharge lamp. An arc discharge tube is positioned in a hermetically sealed jacket. The jacket contains a partial pressure (e.g., 400 torr nitrogen) of a gas that will aid in starting the discharge and one of the arc tube lead-ins has an electrical conductor affixed thereto and exposed to the partial pressure of the gas. An outer conductor extends on the outside of the jacket and is electrically connected to the other lead-in. When voltage is applied to the electrodes a capacitive coupling takes place between the inner conductor and the outer conductor which generates a discharge that causes a breakdown in the arc generating and sustaining medium within the arc tube and causes the lamp to start.

Capacitive coupling starting aid for metal halide lamp

A ballast for a mercury-free, metal halide arc lamp having a quartz or fused silica envelope. The ballast provides a square-wave voltage, which substantially reduces or eliminates the re-ignition voltage in the mercury-free, metal halide arc lamp. The ballast reverses the voltage polarity, and reestablishes the arc current in the opposite direction, before the free halogen in the envelope can quench the arc.

Square wave ballast for mercury free arc lamp

A system and method for the operation of a mercury free high intensity discharge lamp is disclosed which provides lamp longevity and improved photometric results regardless of the orientation of the lamp. To this end, an acoustically modulated ballast without off-time and low power time is supplied to the lamp.

System for and method of operating a mercury free discharge lamp

A highly efficient discharge lamp has a color rendering index of about 85, a lumens per watt rating of about than 90, a correlated color temperature of 3000.degree. K., and a wall loading of about 21 W/cm.sup.2. The lamp has an outer glass envelope and a pair of electrical conductors extending into the interior of the glass envelope; a quartz discharge tube disposed within the outer envelope and including a pair of spaced electrodes which are electrically connected to the electrical conductors for creating an electrical discharge during operation of the lamp, the discharge tube having an arc chamber. An arc generating and sustaining medium is provided within the arc chamber and includes the halides of sodium, scandium, lithium, dysprosium and thallium, a fill gas selected from argon and xenon, and a given quantity of mercury to achieve a desired lamp voltage. In a preferred embodiment of the invention the halides are iodides and are present in the mole ratio of about 24-44:1:9.5:&gt;3&lt;4, while the thallium is present in an amount of about 0.35 to 0.45 mg/cm.sup.3 of arc tube volume.

Metal halide lamp with improved color characteristics

A highly loaded, double ended arc lamp has a cylindrical arc chamber with a volume of 56 cc and an arc length of 108 mm. The metal halide fill is limited to amount below 0.6 mg/cc and comprises HgI.sub.2 ; NaI/CsI in a 6:1 weight ratio; and scandium metal. The 2000W lamp is employed for stadium lighting.

Heavily loaded double-ended arc lamp

In a mercury vapor arc discharge tube having a pair of electrodes, an emissive material disposed on the electrodes consists essentially of a single phase compound of Ba.sub.x Sr.sub.1-x Y.sub.2 O.sub.4 where x is from about 0.25 to about 0.95.

Mercury vapor discharge device

An apparatus and method for accurately dosing and dispensing mercury. The apparatus includes a reservoir containing mercury and a capillary tube extending from the reservoir of mercury to a dispensing needle and having an inlet located intermediate a pair of remotely located ends. The apparatus adjusts the height of a column of the mercury within the capillary tube and measures the height of the mercury column. In one embodiment, a digital vision system comprising a TV camera and monitor digitizes the image of the mercury column within the capillary tube and automatically determines the height of the column. A source of gas is supplied to the inlet in the capillary tube such that a predetrmined amount of mercury is separated from the mercury column and dispensed from the other one of the remotely located ends of the capillary tube.

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Malden, MA, United States of America

Nanu Brates