Abstract: A light that meets Federal Aviation Administration requirements for marking powerlines or powerline support structures that is powered from the magnetic field created by the conduction of electricity along a powerline. The energy in the naturally occurring magnetic filed induces an electric current in a specialized coil within the device that delivers a constant voltage to a lamp. The lamp is focused through a lens into the beam pattern required for marking powerline support structures.

Abstract: An impedance matching circuit for a self-oscillating electrodeless fluorescent lamp ballast of the type having an inductor connected in series with the parallel combination of a capacitor and the lamp's drive coil includes an additional capacitor connected in series with the drive coil. The capacitance value chosen for the additional capacitor is dependent on: stresses on the parallel capacitor; matching the impedance of the ballast; and the impact of the capacitor on the loaded coil phase angle. The additional capacitor reduces the phase angle presented to the ballast, thereby lowering the sensitivity of the ballast to component and lamp variations. In addition, the overall impedance of the network is reduced, such that the required inductance of the series inductor is reduced; hence, the inductor can have fewer turns and lower conduction losses.

Abstract: Silver metal and nickel silicide are added to the fill of an electrodeless high intensity metal halide discharge lamp, which includes at least one metal iodide as a fill ingredient, for controlling the iodine vapor level therein. The nickel silicide acts to getter oxygen which has been introduced into the arc tube during lamp processing, thereby avoiding oxidation of the metal iodide portion of the fill and a concomitant release of free iodine into the arc tube. The silver acts to getter free iodine available from the metal iodide(s) of the fill as metal diffuses into the quartz arc tube wall, forming silver iodide (AgI). The combination of silver and nickel silicide acts to control the iodine level below an arc instability threshold to promote and maintain arc stability. In addition, neither silver nor nickel silicide attack the quartz arc tube wall. Lamp performance and lamp life are thus substantially improved.

Abstract: A power supply for providing a stable operating current to a magnetron-excited lamp. The power supply includes a DC to DC inverter for driving a primary winding of a high voltage transformer. The DC to DC inverter has a circuit including two pairs of switching elements for connecting a DC voltage supply to the primary winding. During each half of the switching cycle, one of the switching elements is pulse width modulated while the other remains on for a substantially fixed period of time. During the second half of the cycle, the remaining pair operates so that one switching device is on for a pulse width modulated period of time, and the other is on a substantially constant amount of time. The on time for the pulse width modulated switching elements is defined by an input voltage setting representing a desired brightness level for the lamp, the output magnetron current, and a representative of the integral of the current flowing through the primary of the inverter transformer.

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: A plasma source for generating a plasma in a chamber in conjunction with a radio frequency generator is described. The plasma source comprises a coil spiral, at least one insulator and at least one capacitor. The coil spiral conducts the radio frequency wave from the radio frequency generator and induces a plasma in the chamber. It comprises at least two segments. Each insulator and capacitor couple two adjacent segments of the coil spiral together.

Abstract: An amalgam is accurately placed and retained in an optimal location near the cold spot of an electrodeless SEF lamp for operation at a mercury vapor pressure in the optimum range from approximately four to seven millitorr. The amalgam is positioned at the tip of an extended exhaust tube near the apex of the lamp envelope by forming an indentation in the exhaust tube and, in some embodiments, a dose locating member in combination therewith. An evacuation hole is formed below the indentation for evacuation of the lamp envelope, or bulb, during lamp fabrication. In an alternative embodiment, the extension of the exhaust tube is situated perpendicular to the main portion of the tube to allow for lateral adjustment of the position of the amalgam, thereby allowing for even further control of the amalgam operating temperature.

Abstract: A circuit arrangement for operating a discharge lamp by means of a high-frequency current includes a switching device for generating the high-frequency current from a supply voltage, a modulator for the substantially square-wave modulation of the amplitude of the high-frequency current at a modulation frequency f, and an apparatus (M) for limiting the interference with infrared systems caused by the discharge lamp. The limiting apparatus (M) comprise a circuit N for providing a gradual increase in the rate at which the amplitude of the high-frequency current decreases at the end of a square wave of the square-wave modulation. This provides a considerable reduction in the interference with infrared systems caused by a lamp operated by the circuit arrangement.

Abstract: An electrodeless SEF fluorescent discharge lamp of the type having an envelope with a re-entrant cavity formed therein for containing an excitation coil includes an amalgam positioned for maintaining an optimum mercury vapor pressure during lamp operation. An exhaust tube extending through the re-entrant cavity has an extension into the envelope toward the apex of the lamp envelope. The exhaust tube extension has a rim portion for holding an amalgam support in position within the lamp envelope. The amalgam support preferably comprises a wire wrapped about and held in place by the rim portion. At the other end of the wire, an amalgam is wetted to a wire screen or helical wire structure at a predetermined optimal location within the lamp envelope. Alternatively, two amalgams are supported by the amalgam support at predetermined optimal locations for starting and steady-state operation of the lamp, respectively.

Abstract: An electrodeless SEF fluorescent discharge lamp of the type having an envelope with a re-entrant cavity formed therein for containing an excitation coil includes an amalgam positioned for maintaining an optimum mercury vapor pressure during lamp operation. The amalgam is doped with a magnetic material, such as iron, cobalt, nickel, aluminum or tungsten, and is initially located in an optimal operating position using a magnetic field generated by a magnet situated about the lamp envelope. Advantageously, the magnetic field can be used to relocate the amalgam within the exhaust tube, as desired, during lamp processing steps. After processing, the magnet is removed, and no amalgam holder is required.

Abstract: Disclosed is an electrodeless, low pressure gas discharge lamp. The lamp includes a vitreous envelope containing a metal vapor and an inert gas. The envelope is shaped with an external chamber for receiving an electrical excitation circuit. The excitation circuit is effective for exciting the metal vapor to emit light with electromagnetic fields that are passed through the vitreous envelope from outside, to inside, the envelope. A circuit supplies electrical power from power mains to the excitation circuit. A transparent, electrically conductive coating is disposed on the inner surface of the vitreous envelope for suppressing electromagnetic interference on the power mains. An electrically conductive coating is disposed on the outer surface of the vitreous envelope; it is capacitively coupled to the inner conductive coating, via a wall of the vitreous envelope, and is maintained at a suitable potential for suppressing electromagnetic interference on the power mains.

Abstract: A high power lamp which utilzes a lamp fill containing sulfur or selenium, or compounds of these substances. An electrodeless lamp utilizing such a fill at a pressure at least as high as 1 atmosphere is excited at a power density in excess of 50 watts/cc. An arc lamp utilizing the fill at a pressure at least as high as 1 atmosphere is excited at a power density of at least 60 watts/cm.

Abstract: A cost-efficient electrically conductive screen and shield for substantially shielding radio frequency electromagnetic radiation emitted beyond the discharge vessel and the electronic circuitry of an electrodeless discharge lamp is disclosed. The conductive screen and/or shield is disposed outside the space occupied by the gaseous mixture and is grounded to the power supply. This shielding reduces the emission of electromagnetic radiation and, in particular, enables the discharge lamp to comply with FCC standards imposed with respect to the maximum admissible level of interference with wireless communication equipment such as radios and televisions.

Abstract: A push-pull Class E amplifier is used to provide an efficient transfer of power to the induction coil in an electrodeless discharge lamp and to minimize the amount of radio frequency interference emitted by the lamp into the surrounding environment.

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 fluorescent lighting system that includes a gas containment vessel having an internal phosphor coating and containing an ionizable gas, field concentrator electrodes supported inside or outside the gas containment vessel, and an RF power source coupled directly or capacitively to the field concentrator electrodes.

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: An atomic clock system employs one of a family of ion trap configurations confining an ion in a potential well, such that a vibrational frequency confined ion may be measured accurately. The ion traps disclassed for use in such atomic clock systems include configurations of ring-shaped conductive members, or sheets of conductive material having circular holes therein. The trap apparatus further has a means to apply an RF field such that the resulting electric field being generated in a space defined by the conductive members has a characteristic of a substantially quadrupole field whereby a charged particle, being injected into the space, is confined in said field, maintaining a dynamic equilibrium condition.

Abstract: A method and circuit for providing stability during dimming of an electrodeless high intensity metal halide discharge lamp driven by a microwave source. Light from the lamp is rapidly dimmed to a low level in a stable manner while preventing the possibility of lamp extinction. Remote optical sensing of lamp light output is coupled with power control circuitry which modifies power delivered to the lamp based on the light response to well defined pulses of power in the output of the microwave source. Power delivered to the lamp is increased when the rate of light drop exceeds a predetermined rate and also, is controlled based on the overall light emission intensity. As a result, stable dimming is achieved regardless of the initial conditions of the discharge. The dimming method disclosed is more forgiving of light-source-system manufacturing tolerances than is presently available using absolute light intensity control alone when source output power is limited.

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 electrodeless discharge lamp includes a single type auxiliary electrode for preliminary discharging, disposed on or adjacent to outer peripheral wall of lamp tube at a position for being electrostatically coupled to interior space of the tube, and supplied with a power from a second high frequency power source other than a first high frequency power source supplying a high frequency power to a main induction coil on the tube, whereby the lamp is made to attain an excellent startability without requiring any large size high frequency power source.

Abstract: A discharge tube including a tubular vessel which is filled with gases, and including a first gas and second gas, the first and second gases being different in excitation level and luminous color from each other. A first electrode unit axially applies an electric field to the vessel to generate a positive column in the vessel. A second electrode unit applies an electric field to the vessel to generate a negative glow in an area, the area extending substantially along a wall surface of the vessel and confronting the positive column generated by the electric field applied by the first electrode.

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: An intermediate voltage or cable marker with a gas filled lamp with reflectively enhanced conspicuity comprising an inner conductive coating in an opaque shell; the shell being mountable on an the intermediate voltage line and having one end of the gas filled lamp electrically connected to the intermediate voltage line or grounded cable and the other end electrically connected to a electrical coil in series with the conductive inner shell coating; the gas filled tube being mounted in a reflective chamber shaped to increase both lateral and vertical conspicuity.

Abstract: A microwave powered discharge device which utilizes a TM.sub.NMO cavity. A conductive body is positioned at a null in a discharge device which utilizes a TM.sub.210 cavity to reduce direct coupling from the microwave coupling means, e.g., slot of the cavity. A plurality of TM.sub.110 cavities are ganged together, and a single discharge tube extends through all of the cavities.

Abstract: An assembly includes an electrodeless discharge lamp disposed between a pair of field applicators, and an integral impedance matching structure for matching the impedance of the lamp and field applicators to the impedance of a power source. The structure includes a Tee junction, a transmission line including a first branch connecting a first output of the Tee junction to one of the field applicators. A second branch of the transmission line connects a second output of the Tee junction to the other field applicator. The difference between electrical lengths of the first and second branches are substantially shorter than a half-wavelength. The assembly is less complex and more compact than prior art which utilizes odd mode excitation via a half-wavelength balun transformer.

Abstract: An electrodeless low-pressure discharge lamp having a sealed discharge vessel filled with a metal and a rare gas and having a cavity. An inductive device is disposed in the cavity for generating a high-frequency electric field inside the discharge vessel during lamp operation. The inductive device includes a winding of metal wire surrounding a cylindrical core of magnetizable material. A cooling body is in contact with the cylindrical core for removing heat generated in the core during lamp operation. The cooling body is closed in a gastight manner and includes a condenser, an evaporator, a liquid, and a capillary structure (T, U) which comprises a winding (U) of gauze surrounding a vapor channel (V) for transporting the liquid from the condenser to the evaporator. The capillary structure has a central partition wall (T), which divides the vapor channel in two, and is connected along two opposing longitudinal sides thereof to the gauze winding (U).

Abstract: An electrodeless discharge lamp includes a discharge vessel containing an ionizable vapor, a generator for providing a high frequency signal, and an induction coil adjacent the discharge vessel and connected to the generator. The induction coil is shaped in the form of a planar spiral. The spiral coil is formed of wire or made of metal etched in a spiral pattern onto a substrate. The electrodeless discharge lamp having a spiral induction coil shows low lumen depreciation, a high linear relationship between light output and power input and produces low radio frequency interference.

Abstract: A high intensity discharge lamp having a fill including at least one rare earth metal iodide has an additional metal component for avoiding a substantial loss of the metal component of the fill and the attendant substantial buildup of free iodine, thereby increasing the useful life of the lamp. During lamp operation, the additional metal component combines with iodine in the vapor phase, forming a relatively stable iodide and thus reducing the total level of free iodine in the lamp. As a result, arc instability is avoided. The additional metal component also emits visible light and hence improves efficacy. Moreover, the additional metal component does not attack the arc tube wall by reducing silica. Suitable additional metal components include indium and thallium.

Abstract: A high-pressure glow discharge lamp (1) having a planar discharge vessel (2) which is sealed in a vacuumtight manner, which surrounds a discharge space (3) filled with a gas mixture which forms excimers, and whose parallel walls (4, 5) are formed from a dielectric material. The surfaces (6, 7) of the walls (4, 5) remote from the discharge space (3) are provided with planar electrodes (8, 9). At least one (5) of these walls with its associated electrode (8) is at least partly transparent to the generated radiation. The gas mixture includes at least one of the rare gases Xe, Kr and Ar for forming an excimer and at least one of the halogens I.sub.2, Br.sub.2, Cl.sub.2 and F.sub.2. The partial pressure of the substance forming the excimer is at least 10 and at most 600 mbar in the case of Xe and/or Kr and at least 10 and at most 1000 mbar in the case of Ar. The partial pressure of the halogen is between 0.05 and 5% of the partial pressure of the substance forming the excimer.

Abstract: An excitation coil for an electrodeless fluorescent lamp of the type having a core of insulating material, is made of a metal having a low thermal expansion coefficient which is plated with a high-conductivity metal. An insulating coating is applied over the metal plating. An exemplary coil includes a molybdenum wire, plated with silver, and finally coated with alumina. The result is a thermally stable excitation coil that maintains its shape, even at high operating temperatures, and hence maintains its impedance characteristic over the operating range of the lamp.

Abstract: An electromagnetic discharge apparatus including a solid state supply or lamp ballast for energizing an electrodeless high intensity discharge (HID) lamp in a dual-ended fashion. A low power signal from a high frequency oscillator is split into two separate signals with definite phase relationship which are coupled to separate power amplifiers. In one embodiment, the signal from the high frequency oscillator is mixed with a signal from a modulation oscillator to AM, FM or pulse-width (PWM) modulate the power delivered to the lamp. This technique permits better control over the balance of power delivered to the ends of the lamp.

Abstract: The electrodeless low pressure sodium vapour discharge lamp which has a discharge vessel (1) containing sodium vapour and inert gas. The discharge vessel (1) has an enveloping part (10) and connected therewith at a first end of the discharge vessel (1) a sunken part (20). In the sunken part (20) is a body (30) of soft-magnetic material which is surrounded by an electric coil (31). The discharge vessel (1) is enclosed in an outer bulb (40). The inner surface (2) of the discharge vessel (1) has a layer (4) of borate glass. The borate glass which covers the sunken part (20), is sintered. The invention renders it possible to make parts of construction glass which have a layer of borate glass at an outer surface.

Abstract: A microwave-powered discharge lamp having a microwave cavity, a discharge lamp mounted within the cavity, a reflector for light emitted by the lamp mounted outside the cavity, and a non-conductive reflector mounted within the cavity for outwardly reflecting light emitted from the lamp.

Abstract: A starting circuit for an electrodeless HID lamp includes a visible light radiator for illuminating a gas probe starter during lamp starting. In one embodiment, a light emitting diode (LED) illuminates the gas probe starter via a quartz tube. Excitation is provided to the LED by the same source used to excite the gas probe starter.

Abstract: An electrodeless low pressure discharge lamp, preferably filled with deuterium gas, is provided with a cylindrical envelope made from quartz glass and surrounded by a cylindrical excitation coil driven at between 10 and 800 MHz. Within the lamp envelope, there is provided a cylindrical aperture member made from boron nitride which in a radial direction extends to the inner surface of the envelope and which is provided with an uninterrupted coaxial channel for confining to a small diameter the plasma discharge arc generated during operation of the lamp, the aperture member having an optical axis extending through coaxially with its channel, the radiation emitting in a directed pattern along the optical axis.

Abstract: An electrodeless fluorescent lamp of the type having a solenoidal drive coil wound about a ferrite core includes an inner shield between the coil and the core and further includes an outer shield about the coil. The shields are preferably constructed of sheets of flexible polyimide material with vertical bands of metal etched thereon. The metal bands are connected to ground in order to shield the core and the plasma from the electric field generated about the drive coil. By thus shielding the core, the capacitance between the coil and the core is effectively short-circuited, substantially reducing or eliminating dielectric losses of the core. The outer shield substantially reduces the EMI generated by the drive coil.

Abstract: A fluorescent light source includes multiple fluorescent lamp tubes driven in parallel by a single RF source. The fluorescent lamp tubes can be twin tube fluorescent lamps or straight fluorescent lamps. RF electrical energy is capacitively coupled to low pressure discharges within each fluorescent lamp tube. External capacitive coupling electrodes can be formed at or near the ends of each fluorescent lamp tube. Alternatively, cold cathode electrodes can be located within the fluorescent lamp tubes. Ballasting of the fluorescent lamp tubes is provided by capacitive coupling between the plasma of the low pressure discharge and the electrodes, thus eliminating the need for external ballasting components.

Abstract: An ultraviolet starting aid is formed in a metal halide arc discharge lamp by forming a cavity in a press seal portion of an arc tube. An electrode is provided in the cavity which either extends external to the press seal, or the electrode may be a portion of molybdenum ribbon used in the press seal.

Abstract: An electrodeless HID lamp formed with a power balanced coupling structure is disclosed. Microwave transmission to the discharge capsule is divided into two channels having an electrical length differential of about a half wave length. A balancing strap line is coupled between the two transmission lines where they deliver power to the field applicators for the discharge capsule. The strap line balances the power delivery between the two ends of the discharge tube.

Abstract: An electrodeless HID lamp having a quartz arc tube having a gas fill contained therein, is energized to a discharge state upon the introduction of a high frequency RF current in close proximity thereto, also includes a starting aid stem which extends from the arc tube. An outer jacket surrounds the arc tube and a portion of the starting aid stem. The outer jacket is pinch sealed at the end from which the starting aid stem extends. This pinch sealing results in the formation of a sealed space between the outer jacket and the arc tube and further allows that, by the gripping of the starting aid stem at the pinch seal region, the arc tube is supported in a fixed non-contacting position within the outer jacket. A sealant material can be applied around the starting aid stem at the pinch seal region to prevent leakage of the sealed space formed within the outer jacket.

Abstract: A high-efficiency Class D amplifier is described. In one embodiment, the amplifier contains two transistors which are turned on and off in sequence, the output being taken from the common node between the transistors. The efficiency of the amplifier is substantially increased by insuring that voltage across each of the transistors is substantially zero when it turns on. This advantage is achieved by connecting an inductance to the common node, so that the electrical energy stored in any stray capacitance is transferred to the inductance before any transistor is turned on.

Abstract: An arc stabilization arrangement for a discharge lamp having a light transmissive arc tube containing a fill of gas excitable to a discharge state upon introduction thereto of a drive signal having a predetermined frequency associated therewith, includes a modulating arrangement effective for providing a modulating signal which is imposed onto the drive signal. The modulating signal has a frequency associated therewith which approximates the acoustic resonance of the gases within the fill, such modulating signal frequency being less than the frequency of the drive signal. In one embodiment of the invention the modulating arrangement is an amplitude modulating scheme effective such that a modulating amplitude of greater than about 5% of the amplitude of the drive signal is achieved. In yet a further implementation of the present invention, the frequency of the modulating signal is swept about a range of frequencies so that a varying acoustic resonance frequency can be encompassed by the modulating signal.

Abstract: A source of IR-radiation, having an enclosure defining between its walls a sealed-off, electrode-less chamber, the walls having at least one portion transparent to IR-radiation, and the chamber containing a gas mixture of at least one, molecular, IR-active gas, of at least one buffer gas and of at least one noble gas. A method for producing a source of IR-radiation is also described and claimed.

Abstract: A fluorescent light source includes a fluorescent lamp having first and second electrodes at or near the ends thereof for capacitive coupling of RF electrical energy to a low pressure discharge within the fluorescent lamp and an RF source having a first output lead electrically coupled to the first electrode and a second output lead electrically coupled to the second electrode. The electrodes include circuitry for inducing an RF magnetic field within the fluorescent lamp in the region of the electrodes. The RF magnetic field improves the performance of the capacitively coupled RF light source by creating an auxiliary inductive RF discharge near the capacitive coupling electrodes. The inductive discharge locally increases the plasma density and the electrode sheath capacitance and provides a reduction in RF voltage across the capacitively coupled fluorescent lamp.

Abstract: The electrodeless low-pressure discharge lamp has a lamp vessel (1) having a cavity (2) at an end portion (3) thereof. An electric coil (4) surrounding a plastic sleeve (5), wherein a liquid-filled tubular container (7) surrounded by a soft-magnetic core (6) is present, is accommodated in the cavity (2). The plastic sleeve (5) is substantially filled up with an elastic polymer. Additionally, the tube (5) may be enveloped by an elastic polymer (9). The elastic polymer ensures a relatively low operating temperature of the members inside the cavity (4).

Abstract: A fluorescent light source includes a twin tube fluorescent lamp having first and second electrodes at or near the ends thereof for capacitive coupling of RF electrical energy to a low pressure discharge within the fluorescent lamp and a RF source having a first output lead electrically coupled to the first electrode and a second output lead electrically coupled to the second electrode. The capacitive coupling electrodes can be conductive layers on the outside surface of the twin tube fluorescent lamp. In an alternative configuration, the electrodes are cold cathode electrodes located within the twin tube fluorescent lamp. Filaments for emitting electrons are not required. When the RF voltage applied to the fluorescent lamp is not sufficient to initiate discharge, a starting device can be utilized. The fluorescent light source preferably includes a lamp base for supporting the fluorescent lamp. The RF source can be mounted within the lamp base.

Abstract: The present invention describes an apparatus and method for shutting off an electrodeless lamp such that it can be restarted instantaneously at any time. The method involves reducing the applied microwave power in a controlled way the moment the lamp is turned off. The reduction of power is accomplished by modulating the microwave power with an ever decreasing duty factor or a decrease of analog power. This reduction in power results continually in reduced light output and lamp cooling while maintaining partial ionization of the lamp fill. Circuitry to accomplish this is also presented.

Abstract: An improved apparatus for delivering energy to two field applicators includes a power divider electrically coupled to a planar transmission line connecting the two field applicators. The power divider receives an input microwave signal and delivers a first power signal to an applicator along a first leg of the line, and delivers a second power signal to the other applicator along a second leg of the line. The power divider is coupled to the transmission line at a point which is remote from the applicators such that the power signals will encounter substantially identical discontinuities as the signals are coupled into their respective applicators.

Abstract: This invention provides for a light emitting device which comprises an envelope of electrically insulative material which defines within its boundaries an ionization chamber. A noble gas is disposed within the chamber and two spaced electrodes are located on the light emitting device such that the electrodes are in electrical communication with the interior of the chamber. At least one conductive member is disposed on the device and arranged to define a tortuous path between the two electrodes but without providing a direct electrical connection between the two electrodes. When a high frequency alternating voltage is applied to the electrodes the electrical interaction between the electrodes and the conductive member causes an ionization path between the electrodes to substantially follow the tortuous path.