Abstract: A dimmable electrodeless light source includes an electrodeless lamp, an electronic ballast and a dimming module. The light source further includes coupling transformers coupled to the electrodeless lamp for inductively coupling power to the lamp to generate light. An auxiliary winding electromagnetically coupled to the primary winding of at least one of the coupling transformers is driven by switching circuitry in the dimming module. The switching circuitry is pulse width modulated to control the average brightness of the light generated by the electrodeless lamp. An exemplary application for the dimmable electrodeless light source is as a backlight for a video display device, such as a liquid crystal display unit. The dimmable electrodeless light source further includes a magnetic shield device that is operably positioned with respect to the electrodeless lamp.

Abstract: A dimmable electrodeless light source includes an electrodeless lamp, an electronic ballast and a dimming module. The light source further includes coupling transformers coupled to the electrodeless lamp for inductively coupling power to the lamp to generate light. An auxiliary winding electromagnetically coupled to the primary winding of at least one of the coupling transformers is driven by switching circuitry in the dimming module. The switching circuitry is pulse width modulated to control the average brightness of the light generated by the electrodeless lamp. An exemplary application for the dimmable electrodeless light source is as a backlight for a video display device, such as an liquid crystal display unit.