Abstract: An electrostatic shield is provided between the induction coil and the arc tube of an electrodeless HID lamp. In one embodiment, the shield is a transparent glass cylinder coated with a thin, transparent, conductive layer of tin oxide. In another embodiment, the electrostatic shield is a conductive, transparent tin oxide coating applied to either the inner or outer surface of an outer light-transmissive jacket surrounding the arc tube. The tin oxide layer is discontinuous so as to minimize currents induced in the conductive tin oxide layer by the induction coil. The thickness of the tin oxide layer is sufficient to make it conductive and form an approximately equipotential surface, thereby shielding the arc tube and plasma discharge from intense electric fields, reducing arc tube wall damage and increasing lamp life. In addition, tin oxide functions as an infrared reflector which returns infrared radiation to the arc tube, resulting in higher efficacy.

Abstract: An electrodeless HID lamp of the type having an excitation coil disposed about an arc tube for exciting a plasma arc discharge therein includes a light-transmissive outer envelope disposed about the arc tube and a light-reflective coating on the upper portion of the arc tube. Thus, light emitted by the arc discharge radiates in a forward direction through the lower portion of the arc tube. An elongated support for the arc tube is situated within the outer envelope and extends in the forward direction through the corresponding lower end of the outer envelope. According to one embodiment, the arc tube support is tubular and contains therein a discharge starting aid. The lamp further preferably includes a getter disposed within the outer envelope for removing gaseous impurities therefrom. A getter support is attached to the upper end of the lamp envelope in order to optimize the position of the getter therein, while avoiding oxidation of the getter material during the lamp sealing process.

Abstract: A gas probe starter for an electrodeless HID lamp includes a getter for removing gaseous impurities from the fill contained in the starting chamber of the gas probe starter. In a preferred embodiment, a metal foil having active getter material disposed on the surfaces thereof in the form of a sintered powder is inserted at an optimum location in the starting chamber which depends on the optimum operating temperature of the particular getter material.

Abstract: An electrodeless high intensity discharge (HID) lamp having an arc tube, a starting aid, and an outer jacket all integrally formed of fused quartz, includes an excitation circuit for providing RF energy effective for initiating and maintaining a gas discharge within the arc tube. The arc tube is positioned within the outer jacket such that a minimum space exists between the outer jacket and the arc tube thereby allowing the efficient coupling of such RF energy to the arc tube by means of an excitation coil wound in close proximate location to the arc tube. The starting aid is of a substantially smaller dimension than the arc tube thereby allowing for a second spacing to occur above the arc tube. This second spacing is effective for optimum thermal management of heat generated within the outer jacket. The upper end of the outer jacket has an integrally formed annular groove for receiving an annular support member effective for securing the HID lamp to a lighting fixture.

Abstract: A method for applying a protective coating to the inner surface of the arc tube of a high-intensity metal halide discharge lamp involves dosing the arc tube with an inert gas that is doped with a metal hydride gas. Preferably, the metal hydride gas comprises silane. The arc tube is heated to a sufficiently high temperature to decompose the silane gas. As a result, silicon is deposited as a protective coating on the inner surface of the arc tube wall. The hydrogen gas that is generated by the silane decomposition is removed from the system either by pumping it out before dosing the arc tube with the final arc tube fill, or by diffusion through the arc tube wall during operation of the lamp.

Abstract: A protective coating of suitable composition and thickness is applied to the inner surface of the arc tube of a high-intensity, metal halide discharge lamp in order to avoid a substantial loss of the metallic component of the metal halide fill and hence a substantial buildup of free halogen, thereby extending the useful life of the lamp. A preferred lamp structure includes a fused silica arc tube with a silicon coating. The silicon coating is preferably applied to the arc tube using a chemical vapor deposition process.

Abstract: An electrodeless high intensity discharge lamp having an excitation coil disposed about an arc tube includes thermal apparatus for ensuring that a metal halide condensate forms a protective film on the portion of the arc tube which is nearest the plasma arc discharge during lamp operation. For a short, cylindrical arc tube, the thermal apparatus comprises a heat shield situated on the top and/or bottom thereof. In one embodiment, the bottom of the arc tube is concave to ensure that the condensate does not collect on the bottom of the arc tube. The excitation coil may be situated sufficiently close to the arc tube to ensure that enough heat is removed from the side wall of the arc tube to a heat sink so that the protective metal halide film forms on the inner surface of the arc tube wall. An outer glass envelope is preferably situated between the arc tube and the excitation coil, which envelope also functions to remove heat from the arc tube side wall.

Abstract: A starting aid for an electrodeless high intensity discharge lamp comprises a first conductive coil disposed about a second conductive coil, the coils each having a truncated-cone shape. The coils are wound in opposite directions so that voltages induced therein add together to provide a sufficiently high electric field gradient to initiate a plasma discharge in the arc tube. The coils are movable between a starting position adjacent to the arc tube and a lamp-operating position at a predetermined location away from the arc tube.

Abstract: Improved efficacy and color rendition are achieved in a high intensity discharge, solenoidal electric field (HID-SEF) lamp by using a novel combination of fill ingredients, including lanthanum halide, sodium halide, cerium halide, and xenon or krypton as a buffer gas. The preferred lamp structure is that of a short cylinder having rounded edges in order to achieve isothermal lamp operation and further efficacy improvement.

Abstract: A pair of starting electrodes are provided for an electrodeless high-intensity-discharge lamp arc of the type having an envelope situated within the bore of an excitation coil and in the interior of which envelope is to be provided a plasma arc discharge driven by the excitation coil. Each of the starting electrodes is a conductive ring disposed adjacent to an associated one of an opposed pair of envelope surfaces, and connected to an opposite end of the excitation coil. A high-voltage signal coupled between the starting electrodes causes an electric field to be produced sufficient to create a glow discharge in the arc tube, and cause an almost instantaneous transition to a high-current solenoidal discharge to form the discharge plasma responsive to the normal field provided by the excitation coil.

Abstract: A novel excitation coil for both starting and maintaining a plasma arc discharge within the envelope of an arc tube in an electrodeless HID lamp, has first and second solenoidally - wound coil portions, each having an axis substantially in alignment with the axis of the other portion. The coil conductor of each portion may be disposed upon the surface of an imaginary cone having its vertex situated within the arc tube, or beyond the arc tube and within the volume of the other coil portion. The ends of each of the solenoid portions furthest from one another are connected together, and the remaining closely-positioned coil ends provide a sufficiently high starting potential, responsive to receiving an excitation signal, for providing a magnetic field; at any instant the magnetic field of each of the two portions combines in-phase in the volume, between the closer ends of both portions, into which the arc tube is normally inserted.

Abstract: A single starting electrode is provided for an electrodeless high-intensity-discharge lamp arc of the type having an arc tube situated within the bore of an excitation coil and in the interior of which arc tube is to be provided a plasma arc discharge driven by the excitation coil. The starting electrode is a conductive conical spiral having a narrower end disposed adjacent to one of the arc tube surfaces. A high voltage is formed by induction, as the spiral electrode receives an RF magnetic flux, to cause an electric field to be produced sufficient to create a glow discharge in the arc tube, and cause a rapid transition to a high-current solenoidal discharge to form the discharge plasma responsive to the normal field provided by the excitation coil.

Abstract: Improved ease of starting at room temperature while maintaining high efficacy and good color rendition at white color temperatures is achieved in an electrodeless metal halide high intensity discharge lamp wherein a mercury-free combination of arc tube fill materials may include sodium iodide with or without cerium halide, and either krypton or argon as a starting gas.

Abstract: An electrodeless high intensity arc discharge lamp employs an excitation coil comprised of a high-temperature metal, such as tungsten or molybdenum, wound directly on the hot quartz envelope of the arc tube within the interior of the outer glass envelope of the lamp, thereby requiring substantially lower current and voltage from the power supply than such lamps having external excitation coils, while emitting less electromagnetic noise. The excitation coil losses are comparable to those of the external excitation coils or prior electrodeless high intensity arc discharge lamps.

Abstract: A metal vapor discharge lamp includes a cathode comprising a reservoir of liquid cesium. Metallic cesium which is eroded from the cathode surface by the action of the discharge is returned to the reservoir by the combined effects of gravity, evaporation, condensation, and diffusion to provide a highly stable, long-lived lamp.The intense infrared pulse output of cesium vapor discharge lamps of the present invention is well suited for triggering light-activated semiconductor switches through dielectric pipe networks and for pumping neodymium glass or neodymium-YAG lasers.

Abstract: A compact fluorescent lamp comprises a substantially cylindrical, tapered envelope with a correspondingly tapered partition disposed within the envelope so as to define a folded discharge path having a length approximately twice the length of the envelope. The taper of the partition and envelope permit easy assembly of the lamp with minimal disturbance of a prior applied phosphor coating. In accordance with one embodiment of the present invention, the partition is formed using shaping wedges applied to a partially molten glass bulb so as to produce a seamed partition extending almost to the closed end of the bulb. The partition in the lamps of the present invention sealably separate one discharge path portion from another.

Abstract: A metal vapor discharge lamp includes a cathode comprising a reservoir of liquid cesium. Metallic cesium which is eroded from the cathode surface by the action of the discharge is returned to the reservoir by the combined effects of gravity, evaporation, condensation, and diffusion to provide a highly stable, long-lived lamp.The intense infrared pulse output of cesium vapor discharge lamps of the present invention is well suited for triggering light-activated semiconductor switches through dielectric pipe networks and for pumping neodymium glass or neodymium-YAG lasers.

Abstract: Jet engine fuel igniters are excited with a current waveform which maintains an intermediate current value until a discharge has separated from the igniter surface. The current then rises to a higher level to provide sufficient energy for ignition of an air-fuel mixture. Ignition reliability is thus increased and the effects of erosion on the igniter surface are decreased.

Abstract: Electrodes for high current electric discharges in low pressure gases comprise a heated filament, coated with emissive material and surrounded by a hollow emitting surface in the shape of a truncated cone. The electric discharge initially starts from a spot on the filament and transfers to a diffuse mode at the small end of the cone structure.High current fluorescent lamps which include the electrodes of the present invention are characterized by rapid transition from the spot mode to the diffuse mode discharge and by low cathode fall voltage.