Thursday, May 22, 2008

US Patent 7375458 - CNT filament light bulb

The first successful light bulb is often credited to Edison who used carbon treated filaments to produce incandescent light with reasonable lifetimes. However, better materials such as tungsten were later found to improve on the performance of carbon filaments. The tide may be turning back to carbon with the development of carbon nanotubes which this patent from HP uses to create still better filaments. Claim 1 reads:

1. A device comprising:

a carbon-nanotube filament spanning approximately an entire length of the device, the filament being formed of an array of carbon-nanotubes, where a length of a carbon-nanotube is approximately equal to a length of the filament, and where the array of carbon-nanotubes are arranged such that approximately the entire lengths of each carbon-nanotubes are adjacent; electrical contacts in electrical communication with the filament; and

an encapsulant encapsulating the filament and electrical contacts, the encapsulant providing a controlled atmosphere, wherein the filament is configured to emit radiation when an electric current is passed between the electrical contacts and through the filament.

Note: Hon Hai Precision have earlier patented a similar carbon nanotube filament configuration.