Intellectual Property Law

US Patent 7394192 - Uniform CNT distribution for field emission

When fabricating field emission devices (such as displays) using carbon nanotubes a problem of clumping can arise when low diameter nanotubes are formed resulting in an uneven distribution of tubes. Larger diameter nanotubes avoid this problem but require a higher threshold voltage for electron emission and are thus unsatisfactory. This patent from Noritake Co. teaches a manufacturing method capable of forming a mixture of large and small diameter nanotubes to provide a more even distribution without sacrificing the emission efficiency. Claim 1 reads:

1. An electron-emitting source comprising:

a plurality of first carbon nanotubes which are formed on a cathode structure made of a metal containing any one of iron, nickel, cobalt, and chromium;

a catalyst metal layer which is formed on said first carbon nanotubes and made of said metal that forms said cathode structure; and

a plurality of second carbon nanotubes which are formed on said catalyst metal layer and are thinner than said first carbon nanotubes.

Full post as published by TinytechIP on July 07, 2008 (boomark / email).