Abstract: A planar fluorescent lamp having a sealed chamber and divider walls to create a serpentine discharge path is provided with sidewall electrodes. A plurality of sidewall electrodes are spaced from each other and positioned adjacent each sidewall of the sealed chamber. In a preferred embodiment, the sidewall electrodes are planar, cold electrode plates. The electrodes extend generally from one divider wall to the other divider wall along a single sidewall. In alternative embodiments, the sidewall electrodes are positioned within the chamber directly exposed to the mercury vapor, or, alternatively, are separated from the chamber by a dielectric layer. The sidewall electrodes are powered in pairs, each pair being driven at a different frequency than any other pair.