Thursday, June 29, 2006

US Patent 7067098 - Single Walled Nanotube Array

As noted in earlier postings, many of Richard Smalley's (Nobel Prize winner for discovering fullerenes) fundamental patents on single walled nanotubes and their fabrication are only now being issued, even though they have filing dates going back to 1996. Whether this is a deliberate strategy of the patent attorney's or not it may present some potential interference problems. This patent presents a broad claim to two dimensional nanotube arrays. Claim 1 reads:

1. A substantially two-dimensional array comprising single-wall carbon nanotubes, wherein (a) the single-wall carbon nanotubes have ends, (b) said ends are ordered in substantially the same plane, and (c) said ends form the substantially two-dimensional array.

As noted in earlier postings, arrays of vertical nanotubes have found extensive uses as electron emission sources and much investment has already been initiated in developing flat panel displays using such technology. Till Keesmann, the owner of the fundamental patent on electron emitting nanotubes ( also disclosed use of single walled nanotube arrays (see figure 5 and column 3,lines 32-47) although they were referred to as "single-shell carbon nano-cylinders". Keesmann's priority goes back to Aug.23, 1996 in the US but has foreign filing priority to Feb. 22 1995. Smalley's priority goes to Aug. 8, 1996 so Smalley has the US priority but not the foreign priority. I've actually heard about cases like this when I was a Patent Examiner and there is no clear resolution other than an interference hearing.

The one silver lining is that most nanotube array applications can use double walled or multiwall nanotubes instead of single walled nanotubes and thus Smalley's claim may not be that powerful except for applications where single walled nanotubes are absolutely necessary.