Abstract: A high-pressure gas discharge lamp includes at least a lamp tube and two electrodes. The two electrodes are each attached to the lamp tube by a sealed area and, outside the sealed area, each electrode has a perpendicular minimum distance, with respect to its longitudinal axis, from the lamp tube.

Abstract: The invention relates to a high-pressure gas discharge lamp which comprises at least a lamp tube (1) and two electrodes (41, 42), wherein the two electrodes (41, 42) are each attached to the lamp tube (1) by a sealed area and, outside the sealed area, each electrode has a perpendicular minimum distance, with respect to its longitudinal axis, from the lamp tube (1).

Abstract: A high-pressure gas discharge lamp (HID [high intensity discharge] lamp) is described which is in particular free from mercury and suitable for use in automobile technology. The lamp is remarkable in particular for a discharge space (2) which has a volume which is reduced by a given factor in comparison with the volume of the discharge space of known mercury-containing discharge lamps. The quantity of the light-generating substances in the discharge space (2) is reduced by the same factor in the simplest case, or even more strongly. This avoids the risk of an impairment of the imaging properties of the lamp because of non-evaporated light-generating substances which may shade off a portion of the luminous discharge arc (21) and/or the tips of the electrodes (3).

Abstract: A high-pressure gas discharge lamp (HID [high intensity discharge] lamp) is described which is in particular free from mercury and suitable for use in automobile technology. The lamp is remarkable in particular for a discharge space (2) which has a volume which is reduced by a given factor in comparison with the volume of the discharge space of known mercury-containing discharge lamps. The quantity of the light-generating substances in the discharge space (2) is reduced by the same factor in the simplest case, or even more strongly. This avoids the risk of an impairment of the imaging properties of the lamp because of non-evaporated light-generating substances which may shade off a portion of the luminous discharge arc (21) and/or the tips of the electrodes (3).

Abstract: A device and a method for the control of a gas discharge lamp are disclosed. In order to detract as little as possible from lamp life in spite of the luminous flux requirements to be fulfilled during the run-up of the lamp, the lamp is operated with an alternating current in a run-up phase which comprises at least the interval from 1 s to 3 s after lamp ignition, the amplitude of said current rising during the run-up phase. After the rise in the run-up phase, the current may first rise further or remain constant in a transitional phase which preferably follows the former phase, and is subsequently reduced until the lamp enters the stationary operational phase. The time gradient of the current is preferably chosen such here that minimum values for the luminous flux of the lamp are achieved at given moments. Particular advantages are obtained, for example, in the case of Hg-free lamps which are operated with high currents, especially during the run-up.

Abstract: A device and a method for the control of a gas discharge lamp are disclosed. In order to detract as little as possible from lamp life in spite of the luminous flux requirements to be fulfilled during the run-up of the lamp, the lamp is operated with an alternating current in a run-up phase which comprises at least the interval from 1 s to 3 s after lamp ignition, the amplitude of said current rising during the run-up phase. After the rise in the run-up phase, the current may first rise further or remain constant in a transitional phase which preferably follows the former phase, and is subsequently reduced until the lamp enters the stationary operational phase. The time gradient of the current is preferably chosen such here that minimum values for the luminous flux of the lamp are achieved at given moments. Particular advantages are obtained, for example, in the case of Hg-free lamps which are operated with high currents, especially during the run-up.

Abstract: A high-pressure gas discharge lamp (HID [high intensity discharge] lamp) is described which is designed in particular so as to be free from mercury and suitable for use in automobile technology. To achieve improved lamp properties, in particular a substantially equal luminous efficacy compared with lamps of the same power and having a gas filling with mercury, as well as a burning voltage which is as high as possible, a geometry is proposed for the discharge space (2) which raises the temperature of the coldest spot in the lamp to such a degree that the light-generating substances can enter the gas phase to a sufficient extent also without mercury, and in particular in combination with the use of a metal halide as a voltage gradient generator.

Abstract: A high-pressure gas discharge lamp (HID [high intensity discharge] lamp) is described which is designed in particular so as to be free from mercury and suitable for use in automobile technology. To achieve improved lamp properties, in particular a substantially equal luminous efficacy compared with lamps of the same power and having a gas filling with mercury, as well as a burning voltage which is as high as possible, a geometry is proposed for the discharge space (2) which raises the temperature of the coldest spot in the lamp to such a degree that the light-generating substances can enter the gas phase to a sufficient extent also without mercury, and in particular in combination with the use of a metal halide as a voltage gradient generator.

Abstract: A circuit for operating a discharge lamp having circut input terminals for connection to a supply voltage source and an inverter coupled to the circuit input terminals for generating an AC voltage at a frequency f from a supply voltage supplied by the supply voltage source. A piezotransformer has transformer input terminals coupled to the inverter output terminals. Terminals for lamp connection are coupled to the inverter output terminals and is provided for detecting whether the lamp has ignited. A protective device is coupled between the output terminals of the inverter and the transformer output terminals so that the inverter is effectively protected against damage due to ignition pulses generated by the piezotransformer.

Abstract: A circuit arrangement for operating a lamp has circuit input terminals for connection to a supply voltage source. An inverter is coupled to the circuit input terminals for generating an AC voltage with a frequency f from a supply voltage supplied by the supply voltage source and includes inverter output terminals. A piezotransformer has input terminals coupled to the inverter output terminals. Terminals for lamp connection are coupled to the inverter output terminals. A detector detects whether the lamp has ignited. The transformer input terminals are connected to the inverter output terminals only by means of passive components and the inverter comprises means coupled to the detector for changing the frequency f in response to the ignition of the lamp. The circuit arrangement is simple and inexpensive and need not provide a device for switching the piezotransformer out of the circuit after ignition of the lamp.

Abstract: A circuit arrangement for alternatingly, at a frequency f, establishing and extinguishing a discharge in each of a plurality of discharge paths, each of which is associated with a first electrode situated at a first end of the discharge path and with a second electrode situated at a second end of the discharge path. Operating voltages are generated from a supply voltage during operation and are present across respective discharge paths and are periodic at the frequency f. The same operating voltage is present across each discharge path. During operation each discharge path is associated with an auxiliary electrode situated alongside the discharge path and the circuit arrangement further comprises respective switching devices for connecting and disconnecting each of the auxiliary electrodes at the frequency f to a terminal of the circuit arrangement to establish an ignition voltage during a part of each period between one of the electrodes and the auxiliary electrode associated with the same discharge path.

Abstract: A lighting unit according to the invention comprises an electrodeless low-pressure discharge lamp and a high-frequency supply. The electrodeless low-pressure discharge lamp is provided with a discharge vessel which is closed in a gastight manner, comprises an ionizable filling, and has an enveloping portion and a recessed portion surrounded by the enveloping portion, which enveloping and recessed portions of the discharge vessel each support a luminescent layer. The electrodeless low-pressure discharge lamp is in addition provided with a coil which is arranged in the recessed portion of the discharge vessel and which is electrically connected to the supply. The conversion efficiency of the luminescent layer on the recessed portion is relatively high compared with that of the luminescent layer on the enveloping portion. This measure renders possible a lower temperature of the core.

Abstract: An electrodeless low-pressure discharge lamp comprising a glass lamp vessel (1) which is sealed in a gas-tight manner and is filled with a metal vapor and a rare gas, this lamp vessel being provided with a tubular protuberance (2) which accommodates a rod-shaped core (3) of magnetic material surrounded by a wire winding (4) connected to a high-frequency supply unit, by means of which during operation of the lamp an electrical discharge is maintained in the lamp vessel, the inner side of the lamp vessel being provided with a transparent conductive layer (10), which is electrically connected by means of a lead-through member (12) to a conductor, such as a metal rod (11) provided in the core (3), located outside the lamp vessel, this lead-through member (12) being located at the end of the tubular protuberance, and being electrically connected to the internal conductive layer, for example by means of a wire spring (15).

Abstract: An electrodeless low-pressure discharge lamp comprising a lamp vessel (1) which is sealed in a vacuum-tight manner and is filled with a metal vapor (for example mercury) and a rare gas, this lamp being provided with a core (4) of magnetic material (for example ferrite), while during operation of the lamp, and electric field is produced in the lamp vessel by means of a winding arranged to surround this core and a high-frequency supply unit connected thereto, the lamp vessel further being provided with an internal transparent conductive layer (11) and an external conductive layer (12), which during operation of the lamp is connected to one of the mains conductors and which together with the internal conductive layer (11) forms a capacitor.

Abstract: An electrodeless low-pressure discharge lamp comprising a glass lamp vessel sealed in a gas-tight manner and filled with a metal vapor and a rare gas, and a winding on a ferrite core. During lamp operation an electrical discharge is maintained in the lamp vessel by the winding connected to a high-frequency supply. The winding is surrounded by a thin-walled cylindrical metal body or layer which is electrically insulated from the winding, is interrupted at at least one area and is connected during operation of the lamp to one of the power mains conductors.

Abstract: An electrodeless low-pressure discharge lamp having a lamp vessel (1), a core (3) of magnetic material, a first winding (7) arranged to surround the core and connected to a high-frequency supply unit (4), one of the lead-in wires of this winding being electrically connected to a lead-in wire of a second winding (11) with a free end (12), while during operation of the lamp the potential drop between the ends of the second winding is substantially equal to the potential drop between the ends of the first winding and the potential drops in the two windings vary in opposite senses. Interference currents at the supply mains to which the lamp is connected are then strongly suppressed.

Abstract: An electrodeless metal vapor discharge lamp comprising a lamp vessel (1) which is sealed in a vacuum-tight manner and is further filled with a rare gas, which lamp is provided with a core (4) of magnetic material, in which a high-frequency magnetic field can be induced by means of an electric supply unit (7) and a winding (5) arranged to surround the core, an electric field being produced in the lamp vessel (1), the surface area of a cross-section orthogonal to the axis of the winding lying between 20 mm.sup.2 and 60 mm.sup.2, the lamp vessel (1) containing as rare gas krypton and/or argon at a pressure of at most 100 Pa, and the axial length of the winding lying between 8 and 15 mm.

Abstract: An electrodeless low-pressure discharge lamp comprising a lamp vessel (1) sealed in a vacuum-tight manner and filled at least with a metal vapor and a rare gas, the lamp being provided also with a cylindrical core (2) of magnetic material, such as ferrite, a winding (4) arranged to surround the core (2) and an electrical supply unit connected thereto for producing during operation of the lamp an electrical field in the lamp vessel (1). The supply unit is located in a thin-walled metal housing (8) provided in a wall portion (9) of synthetic material, which is partly of conical shape and is provided at its end with an Edison lamp cap (10), and the core (2) accommodates a rod-shaped or tubular body (11) of thermally conducting material connected to the housing (8). In order to improve the ignition properties of the lamp, an electrical insulator (12) is provided between the end of the body (11) and the wall of the housing (8).

Abstract: A discharge lamp having a sealed glass vessel filled with gas and a metal vapor, operated with a supply at a frequency of at least 20 kHz. An interference-suppressing conductive layer is arranged on a wall surface surrounding the discharge, and connected to an electric supply lead-in wire. Preferably, a plurality of insulated metal rings, on the outside of the wall, also surround the discharge.

Abstract: Electrodeless gas discharge lamp having a lamp vessel which is closed in a vacuum-tight manner, the lamp comprising a rod-shaped core of a magnetic material, a member of a heat-conducting material (for example copper) extending at or near the axis of the core, heat generated in the core during operation of the lamp being discharged to the environment of the lamp by the member.