Abstract: A fluorescent lamp is provided that has a plurality of electroded tubes and a plurality of non-electroded tubes. The electroded tubes and the non-electroded tubes each have a proximal end and a distal end. Each proximal end is adjacent a base of the fluorescent lamp. A reflecting mirror is positioned in the proximal end of at least one of the non-electroded tubes or the electroded tubes. The reflecting mirror has a surface reflective of at least some frequencies of visible and ultra-violet light generated by the fluorescent lamp. The electroded tubes can also have a reflecting mirror positioned between the electrode and the end of the tube. In the latter case, an opposite surface of the reflecting mirror can include one or more of an end-of-life composition and/or a runner-up amalgam. A method of placing the reflecting mirror within a tube of a tubular fluorescent lamp is also provided.

Abstract: Aspects of the invention include an electronic ballast and method for controlling current through a lamp to produce various current waveforms through the lamp. In one embodiment, the ballast samples and adjusts the current through the lamp on a micro-second time scale within each half-cycle of the current waveform (i.e., at least twice within a period of a reference waveform). The ballast can accommodate different lamp types, provide arbitrary current waveforms, operate a lamp at multiple power levels, and provide power to the lamp as a function of an operational state of a lamp. For example, in one embodiment, the ballast increases power to the lamp and adjusts the current waveform provided to the lamp as the lamp ages to minimize luminous flux loss caused by darkening of lamp walls and changes in lamp chemistry.