A fully sealed luminescent tube based on carbon nanotube field emission

A fully sealed luminescent tube of 40 cm length and 4 cm diameter based on carbon nanotube field emission is demonstrated. The device shows a homogeneous illumination over the whole length and circumference of the tube and reaches the luminance of conventional fluorescent tubes while being mercury-free, continuously dimmable and with a high illuminance capability. The realization has been made possible with the development of a chemical vapor deposition method to grow nanotubes homogeneously on long metallic wires, which provides an additional possibility to control the mean length and density of the emitters. This control has proven to be of utmost importance as it makes possible to adjust the emission voltage and emission site density needed to reach the target intensity and specifications of the device.