Abstract: The capped high pressure discharge lamp includes a light source (1) having a lamp vessel (1') with a first neck shaped portion (2) to which a lamp cap (30) is fixed. A connection conductor (7) runs alongside the discharge vessel to connect a second current supply conductor (5) extending from a second neck shaped portion (3) to a second contact member (36) of the cap. The lamp vessel (1') is contained by a tubular outer envelope (20), which is filled with air and does not envelope the connection conductor (7). The outer envelope (20, 50) has a narrowing portion (21, 52, 51) which encloses the second current supply conductor (5) or a neck shaped portion (2, 3). The outer envelope is maintained. The lamp is of a simple construction which allows for optimizing the light output or the temperature of the lamp vessel.

Abstract: An illumination unit comprises an electrodeless low-pressure discharge-lamp and a high-frequency power supply unit. The lamp has a gastight closed discharge vessel with an ionizable fill and a coil with turns of a primary and a secondary winding around a core of soft-magnetic material. The power supply unit has input terminals, a first output terminal, electrically neutral with respect to ground, that is connected to a first end of the primary winding, and a further output terminal that is connected to a second end of the primary winding. During nominal lamp operation the primary winding excites a high-frequency magnetic field that maintains an electrical discharge in the discharge vessel and that induces in the secondary winding a potential drop in the direction of a first, with respect to the electrically neutral end, to a second free end that varies in a sense opposite to the potential drop from the first to the second end in the first winding.

Abstract: An illumination unit of the invention comprises an electrodeless low-pressure discharge-lamp (10) and a high-frequency power supply (50). The lamp (10) is provided with a gastight closed discharge vessel (20) with an ionizable fill (21). The lamp (10) further is provided with a coil (30) with turns (31,32) of a primary and a secondary winding (33,34). The power supply unit 50 is provided with input terminals (51a,51b) and is further provided with a first output terminal (52a), electrically neutral with respect to mass, that is connected to a first end (36a) of the primary winding (33) and with a further output terminal (52b) that is connected to a second end (36b) of the primary winding (33).

Abstract: A circuit arrangement suitable for operating low-pressure mercury discharge lamp by means of a high-frequency current includes circuitry (I) for generating the high-frequency current from a supply voltage, and a modulator (II) for the substantially square-wave modulation of the amplitude of the high-frequency current at a modulation frequency f. The circuit arrangement is further provided with circuitry (V) for limiting the amplitude of the re-ignition voltage across the low-pressure mercury discharge lamp to a voltage Vi. As a result, interference with infrared systems caused by a discharge lamp operated by the circuit arrangement is substantially fully suppressed.

Abstract: A circuit arrangement suitable for operating a low pressure mercury discharge lamp by means of a high-frequency pulsatory current comprising circuitry for generating a high-frequency pulsatory current from a supply voltage with a modulator for modulating the high-frequency pulsatory current into a substantially square-wave shape voltage with a current amplitude A, with a modulation frequency f and a duty cycle DC together with circuitry for adjusting the duty cycle DC and circuitry for adjusting the amplitude A.

Abstract: A circuit arrangement suitable for operating a low pressure mercury discharge lamp by means of a high-frequency pulsatory current comprising circuitry for generating a high-frequency pulsatory current from a supply voltage with a modulator for modulating the high-frequency pulsatory current into a substantially square-wave shaped voltage with an amplitude A, a modulation frequency f and a duty cycle DC together with circuitry for adjusting the modulation frequency f and circuitry for adjusting the duty cycle DC.

Abstract: A circuit arrangement suitable for operating a low pressure mercury discharge lamp by means of a high-frequency pulsatory current comprising circuitry for generating a high-frequency pulsatory current from a supply voltage with a modulator for modulating the high-frequency pulsatory current into a substantially square-wave shape voltage with a current amplitude A, a modulation frequency f and a duty cycle DC together with circuitry for adjusting the modulation frequency f and circuitry for adjusting the amplitude A and circuitry for adjusting the duty cycle DC.

Abstract: An electrodeless low-pressure mercury vapour discharge lamp having a discharge vessel with a radiation transmitting envelope and a cavity, which cavity accommodates a core of magnetic material and a wire winding surrounding said core and connected to a high-frequency supply unit. The envelope is provided with a first luminescent layer and the cavity with a second luminescent layer. Of the two or more luminescent materials present the luminescent material with the greatest depreciation is present exclusively in the first luminescent layer on the envelope.

Abstract: Electrodeless low-pressure discharge lamp having a glass lamp vessel (1) which is sealed in a gaas-tight manner and which is filled with at least a metal vapor and a rare gas, said lamp having a first winding (6) which is connected to a high-frequency electric power supply unit and which generates an electric discharge in the lamp vessel (1), one of the supply wires of the first winding being electrically connected to a supply wire of a second winding (12) which extends at the area of the first winding and which has a free end (13), whilst the potential gradient between the ends of the first winding (6) is substantially equal to that of the second winding (12) during operation, ignition antennas (14, 15) being secured to the free end (13) of the second winding (12) and to one end (16) of the first winding (6).