Fluorescent lamp with integral conductive traces for extending low-end luminance and heating the lamp tube

Abstract

A fluorescent lamp (,) includes a tube (,) and a fluorescent gas mixture sealed in the tube. A phosphor layer (,) is deposited on the interior surface of the tube. A pair of internal electrodes (,), connected by a first circuit (,) to a first power supply (,), are located in the tube at opposite ends thereof. The first power supply (,) causes a high-intensity arc discharge between the pair of internal electrodes (,) and, in turn, produces fluorescent light. An opposing pair of conductive traces (,) connected by a second circuit (,) to a second power supply (,), are silk-screened onto the exterior surface of the lamp tube (,) along the length thereof. The second power supply (,) causes the opposing pair of conductive traces (,) to produce a transverse electric field that creates a low-intensity transverse discharge. The low-intensity transverse discharge is used to lower the luminance range of the fluorescent lamp. The conductive traces are formed of a conductive frit, such as a silver ceramic frit. After silk-screening, the lamp tube (,) is fired to melt the frit onto the tube. At least one of the conductive traces (,) is connected by a third circuit (,) to a third power supply (,). The resistivity of this conductive trace is such that the conductive trace functions as a heater when it receives power from the third power supply.