On the carbon nanotube patent landscape
Another set of early researchers working with carbon fibers were R.T.K. Baker and P.S. Harris, who in 1978 published an article entitled "Formation of Filamentous Carbon" in Chemistry and Physics of Carbon which described hollow carbon filaments with nanometer scale diameters (see Figure 5). [FN71] The IBM single-walled nanotube patent (U.S. Patent 5,424,054) referenced this article as potential prior art, but distinguished its disclosed process as being capable of only producing filaments with large diameters generally greater than five nanometers. Based on this distinction, the IBM patent was able to claim a "hollow carbon fiber having a wall consisting essentially of a single layer of carbon atoms."
Footnote 71 is R. T. K. Baker & P. S. Harris, Formation of Filamentous Carbon, Chemistry and Physics of Carbon Vol. 14 (1978), at 83.
IPBiz notes that the abstract for the '054 patent states: The present invention relates to hollow carbon fibers having a cylindrical wall comprising a single layer of carbon atoms and a process for the production of these fibers.
The list of references of the '054 cites:
Baker, "Catalytic Growth of Carbon Filaments", Carbon, vol. 27 No. 3, pp. 315-323, 1989 (no month), but does NOT cite the 1978 Baker/Harris paper. Because the 1978 Baker/Harris paper is NOT a reference cited on the list of references cited on the '054 patent, it was NOT considered by the USPTO as prior art. However, within the disclosure of the '054 patent one has the text:
Baker and Harris in Chemistry and Physics of Carbon, Vol. 14, page 83 (1978) disclose forming VGCF carbon filaments by contacting ethylene or benzene vapor with cobalt at 1000.degree. K. However, these filaments have large diameters generally greater than 5 nm.
One notes that the Baker/Harris article is a REVIEW article. The IBM patent did not discuss the original (pre-1978) papers of R.T.K. Baker OR the patents of Baker.
The summary of the invention for the '054 states:
The present invention relates to carbon fibers having a wall comprising a single layer of carbon atoms. The present invention also relates to a process for making carbon fibers having a wall comprising a single layer of carbon atoms. The process involves contacting carbon vapor with cobalt. Preferably, the carbon vapor is produced by electric-arc heating. Preferably, the cobalt is also vaporized preferably by electric-arc heating. Preferably, the process is carried out in an inert atmosphere.
Note the 2005 IPBiz post entitled Article on carbon nanotubes, which begins with the text: Single-wall carbon nanotubes were discovered in 1991 by Sumio Iijima of Japan, a researcher for Japanese computer giant, NEC Corporation. Iijima's name does not appear in THE CARBON NANOTUBE PATENT LANDSCAPE. The 2005 IPBiz post also notes: IBM also holds an early and fundamental patent on single-wall carbon nanotubes. US Patent No. 5,424,054 has been identified by patent lawyers as one of the ten most important patents that could have an impact on the future development of nanotech. IBM’s patent was licensed to Carbon Nanotechnologies, Inc.
[LBE note: US 5,424,054 is based on an application filed May 21, 1993. It cites only two US patents, none to NEC. To date, it has been cited by 43 US patents.