Abstract: An arrangement including an electrodeless discharge lamp having a sealed envelope enclosing an ionizable medium capable of emitting radiant energy when subjected to a radio frequency field and a circuit for operating the lamp. The circuit includes an oscillator for generating an output signal at a given radio frequency, an RF amplifier responsive to the oscillator output signal, and an output tank circuit including an induction coil and a capacitor connected in parallel. The RF amplifier includes a pair of semiconductor switches operating in a Class E mode. The induction coil is positioned in close physical proximity to the medium in the envelope for coupling to the medium an electric field having a magnitude sufficient to initiate ionization of the medium and a magnetic field for maintaining the ionization. In a preferred embodiment, the amount of EMI/RFI noise generated in the circuit is reduced by symmetrically driving the induction coil.

Abstract: An integrated light source for use in a large scale video display. The light source includes a cylindrical housing containing at least one electrodeless fluorescent lamp and a circuit for starting and operating the lamp. The circuit includes a radio-frequency generator whose output is capacitively coupled to the electrodeless lamp by means of a pair of coupling members mounted adjacent the exterior surface of the lamp's envelope. A strong electric field produced between the coupling members is sufficient to cause breakdown and excitation of the electrodeless lamp fill material. In a preferred embodiment, a circuit coupled to the input of the radio-frequency generator controls operation of the lamp in response to a low voltage control signal. The integrated light source of the present invention overcomes problems in the prior art of premature lamp life due to failures of the electrode or the glass to metal seal.