US Patent 7352559 - CNT field emitter using conduction enhancing gas medium

http://www.freepatentsonline.com/7352559.html

This patent has priority going back to 3/21/2002 and teaches a carbon nanotube field emission device using a gas medium such as argon, neon, xenon, or radon for enhanced lighting. Claim 1 reads:

1. A carbon nanotube electrical device comprising: a) a cathode coated with carbon nanotubes and configured for emitting electrons; b) an anode placed in an electrically conductive relationship with the cathode, such that there is a space between the cathode and the anode; and c) a gas medium placed in the space which participates in the transfer of electrons across the space.

However, some relevant prior art may have been overlooked such as Choi et al. "Fully sealed, high-brightness carbon-nanotube field-emission display" (see Fig. 2a and note that partial pressure of Argon gas is used). Alternatively, see US Patent 6,965,199 with priority from 3/27/2001 and explicitly noting the benefits of inert gases such as argon in carbon nanotube gas discharge tubes (note Fig. 5).