Abstract: A capsule containing a precise amount of a substance such as mercury is mounted in an electrode mount assembly on a temperature sensitive member. At elevated temperatures the capsule is moved away from lamp components by the temperature sensitive member to preclude inadvertent release of the mercury into the sealed lamp. After the lamp has cooled, the temperature sensitive member urges the capsule into biased engagement with a cutting wire so that upon supply of current thereto the capsule is melted and opened to release the mercury.

Abstract: A gas discharge lamp ballast with an indicator of operability of the ballast is disclosed. The ballast circuit comprises circuitry for providing a d.c. bus voltage on a bus conductor with respect to a ground, and a resonant load circuit. The resonant load circuit includes lamp terminals for connecting to a removable gas discharge lamp, a resonant inductor, and a resonant capacitor. The resonant inductor and resonant capacitor are selected to set a magnitude, and resonant frequency, of a bidirectional current in the lamp. Further included is a converter circuitry, including first and second serially connected switches coupled between the bus conductor and the ground, and providing to the resonant load circuit, at a node coupled between the first and second switches, a voltage that alternates between first and second voltage levels.

Abstract: An arc tube of fused silica for a metal halide arc discharge lamp including a fill for the arc tube comprised of a sodium halide, at least one additional metal halide, and an inert starting gas, the arc tube including a tube of fused silica having an inner wall defining an arc chamber, the inner wall of the tube having provided thereon a metal silicate coating which is vitreous and light-transmissive, and which is comprised of a silicate of at least one metal selected from the group consisting essentially of scandium, yttrium, and a rare earth element, and preferably which is the same metal as that of the at least one additional metal halide. Protection of the fused silica arc tube with the metal silicate coating reduces loss of the metallic portion of the fill by diffusion or reaction and corresponding buildup of free halogen in the arc tube.

Abstract: Yttrium-containing phosphors can be stabilized for use in an aqueous slurry containing a binder, which slurry can be used for coating fluorescent lamps by treating with ammonium dihydrogen phosphate and ammonium hydrogen difluoride to inactivate free yttrium ions. The resulting aqueous slurry is stable and provides coated fluorescent lamps having uniform coatings that are bright and long lasting.

Abstract: A double profile drawing tool includes a mandrel having a profile drawing die formed therein with first and second portions extending in opposite directions, associated therewith. The mandrel is disposed in a supported surrounding manner within a structure including a housing body and an embedding component. The embedding component is securely fixed within the housing body by way of a support plate which is joined to the housing body in a shrink fit manner. The structure formed by the housing body, support plate, with the mandrel and embedding component contained therein, is then securely mounted within a U-shaped outer housing member. First and second tapered openings are formed on opposite sides and along the longitudinal axis of the double profile drawing tool, such tapered openings providing communication to the first and second portions of the profile drawing die from opposite directions.

Abstract: The invention relates to an electrode-inlead assembly for electrical lamps which comprises a lead-in-wire connected to a foil made of refractory metal and the foil is connected to a shank made of refractory metal and supporting the electrode.The object of the invention is, that the shank is made of two parallel rods which are joined by their one end portions, and their opposite end portions are welded to the foil, so that the foil is sandwiched between the rods.

Abstract: This headlamp comprises a reflector and a discharge lamp comprising an inner envelope having a longitudinal axis coinciding with the optical axis of the reflector. The inner envelope includes a bulbous portion, a front leg extending along the optical axis from the bulbous portion toward the front of the headlamp, and a back leg extending along the optical axis from the bulbous portion toward the reflector. The discharge lamp further comprises a tubular shroud comprising a first hollow portion surrounding the front leg of the inner envelope, a second hollow portion surrounding the back leg of the inner envelope, and a bulbous portion between the two hollow portions. The bulbous portion of the shroud has a central longitudinal axis, and this central axis is upwardly offset by a small distance (e.g., at least about 0.5 mm) from the longitudinal axis of the inner envelope on which the discharge is located.

Abstract: A replaceable headlamp bulb for automotive applications comprising a discharge light source, a gimbal device, and a plastic lamp base in which the gimbal device is a one-piece construction that allows the light source to be precisely aligned and locked in a specific position with respect to the lamp base. The gimbal device is a cylindrically shaped member made of glass-mica material with a metallic ring fitted in a castellated circumferential groove at one end of the glass-mica member. The light source is mounted at the opposite end of the gimbal device to the ring-fitted portion. The plastic base contains an internal cylindrical opening into which the ring-fitted end of the glass-mica gimbal is inserted and aligned with respect to the plastic base. The gimbal device is locked inside the plastic base by heating of the metallic ring using Radio-Frequency (RF).

Abstract: An auto-starting lamp system comprises an electrodeless high intensity discharge lamp of the type including an arc tube that contains an ionizable fill, an excitation coil surrounding the arc tube for exciting an arc discharge in the ionizable fill at least during steady state lamp operation, and a starter circuit for facilitating arc discharge of the ionizable fill. The system further comprises a controllable r.f. power source for powering the lamp excitation coil, and an electrical network for matching the impedance of the excitation coil to the impedance of the r.f. power source. The impedance-matching network has the same impedance-matching relation during both lamp start-up and steady state lamp operation. A system controller causes the r.f. power source, during lamp start-up, to ramp up in power to a peak level preferably substantially in excess of a steady state lamp operating power level, and then to decrease from the peak level.

Abstract: A power supply circuit for a gas discharge lamp is disclosed. The power supply circuit includes a circuit for providing a d.c. bus voltage on a bus conductor, and a resonant lamp circuit. The resonant lamp circuit includes a gas discharge lamp, a first resonant impedance in series with the gas discharge lamp, and a second resonant impedance substantially in parallel with the gas discharge lamp. The resonant load circuit operates at a resonant frequency determined by the values of the first and second resonant impedances. Further included is a series half-bridge converter for impressing across the resonant load circuit a bidirectional voltage, and thereby inducing a bidirectional current in the resonant load circuit.

Abstract: An electronic ballast can be connected between either a DC power supply or an AC power supply and a gas discharge lamp, such as a metal halide lamp and control the electrical power supplied thereto. An inverter receives a DC power and generates a periodic waveform at a controlled frequency. A resonant circuit is connected to the inverter and tuned to resonate at a predetermined frequency and generate an output voltage. A coupling capacitor is connected between the resonant circuit and the discharge lamp and supplies the output voltage of the resonant circuit thereto. A controller sets the frequency of operation of the inverter near the resonant frequency of the resonant circuit. The controller is responsive to at least a predetermined set point control voltage and to the output voltage of the resonant circuit. The resonant circuit is tuned to increase the voltage from the inverter means to a level sufficient to cause the discharge lamp to enter a glow mode of operation.

Abstract: An electrodeless discharge lamp comprising an arc tube constructed of a light-transmissive material. An exciting structure surrounds the arc tube and is energizable with radio frequency current to develop an arc discharge. A reflective coating of non-conducting insulating material is disposed on the arc tube wall and is located to reflect light from the arc discharge through the arc tube. The reflective coating and the uncoated portion of the arc tube wall are surrounded by the exciting structure so that light from the arc discharge may reach the reflective coating without blockage by the exciting structure and, following reflection by the coating, travel through the uncoated portion of the arc tube wall.

Abstract: This lamp comprises (1) an envelope of vitreous light-transmitting material enclosing an internal space where light is generated and (ii) conductive lead structure projecting into said internal space. Surrounding and sealed to said lead structure is a body of vitreous material formed of particles of vitreous material pressed together and sintered. This body extends through an opening in the envelope that communicates with said internal space. A hermetic seal is provided between said envelope and said body in the interface region between said envelope and said body.

Abstract: An electric arc discharge lamp includes an elongated hollow tubular transparent envelope having a pair of opposite ends, a pair of electrode mounts respectively disposed in the ends of the tubular envelope, and a dosing capsule defining a hermetically sealed annular cavity containing a predetermined quantity of a dosing liquid therein. The dosing capsule has an inner edge defining an opening through the capsule for receiving a portion of one the electrode mounts therethrough such that the capsule is supported by the one electrode mount with the sealed annular cavity substantially surrounding the one electrode mount. The electrode mount includes a glass stem having inner and outer axially-displaced opposite ends, a pair of lead-in conductors extending through the glass stem and from the opposite ends of the glass stem, and an electrode supported between a pair of inner ends of the lead-in conductors adjacent to and spaced from the inner end of the glass stem.

Abstract: An electrodeless high intensity discharge (HID) lamp arc tube having a stabilized condensate location. The arc tube contains a predetermined location or distortion on the inside surface of the arc tube. The distortion may be a protrusion on the inside surface of the arc tube formed during the arc tube forming process. In operation of the lamp, the non gaseous dose remains condensed substantially in the cold spot region formed by said protrusion so that the arc tube walls remain clear for maximal light output, and the arc tube remains stable and efficacious to substantially higher power than is the case for arc tubes without the distortion.

Abstract: An optical coupling assembly is useful for coupling a source of light, having high brightness and focussed at a focal plane, to a plurality of optical light conductors. The coupling assembly includes a light transmissive elongated segmented rod-shaped coupling member formed of a plurality of longitudinal sections and a retainer member for holding the longitudinal sections together in an assembled relationship. The coupling member has a central longitudinal axis and at an input end is disposed at the focal plane of the light source, while at an output end is disposed against leading ends of the plurality of optical light conductors. Each longitudinal section of the coupling member has a plurality of spaced longitudinal surfaces capable of internally reflecting light traveling within the longitudinal section.

Abstract: A high intensity electrodeless metal halide arc discharge lamp wherein RF energy is coupled to the arc discharge, contains a halide of praseodymium alone or in combination with other metals such as one or more rare earth metals, Na and Cs and is essentially mercury free (i.e., < 1 mg per cc of arc chamber volume).

Abstract: A circuit and method for powering a high intensity discharge lamp, such as a high pressure sodium lamp (HPSL) are disclosed. Feedback control is used to achieve a nearly constant amplitude of lamp current so as to attain nearly constant lamp color in a HPSL, and further accommodates considerable variations in a.c. line voltage. The circuit, which shares some features with the method, includes a circuit to supply a d.c. bus voltage and first and second feedback-controlled circuits. The first feedback controlled circuit regulates the bus voltage in response to a first error signal which is derived as a function of peak lamp current and a set point signal for such peak current. The second feedback controlled circuit regulates lamp power in response to a second error signal which is derived as a function of average bus current and a set point proportional to the difference between regulated bus voltage and lamp power.

Abstract: Circuits, and methods of using same, are disclosed for pulse operating a sodium vapor lamp and, in response to gating pulses applied to a resonant ballast, the lamp ignites to develop a quasi-resonant bidirectional current waveform through the lamp, the shape of which is controlled to suppress the excitation of acoustic resonant nodes in the lamp. The quasi-resonant bidirectional current waveform oscillates at a prescribed frequency and contains a first group of harmonics, the harmonic content of which is outside any acoustic frequency region associated with the lamp, and further contains a second group of harmonics having a harmonic content which coincides with such acoustic frequency region. The current waveform is caused to decay substantially at the time of ignition of the lamp to quickly reduce the magnitude of the second group of harmonics to thereby suppress excitation of the acoustic frequency region and prevent arc instability in the lamp.