Carbon Fiber Method Patent Used in B-2 Bombers Not Invalid

The government, in a Court of Federal Claims, invalidated a patent for making carbon fibers (the fibers used in the production of B-2 bombers and F-22 fighter planes) but upon review by the Court of Appeals for the Federal Circuit, the government’s victory was overturned upon a finding that (a) the Zoltec patent was valid under the Patent Act, Section 112 and (b) the patent claims were not invalid (they were patentably nonobvious) over the prior art advanced by the government.  Patent owner Zoltec sued the government for patent damages due to the use of the patented carbon fiber method.

In Zoltek Corporation v. United States, 2014-5082 (Fed. Cir. February 19, 2016) (Available Here), the Court of Appeals for the Federal Circuit reversed the Court of Federal Claims’ (herein “CFC”) judgment of invalidity of Zoltek Corporation’s (herein “Zoltek”) reissue patent, United States Reissue Patent No. Re 34,162 (herein “the ‘162 Patent”) under §§112 and 103.  The Federal Circuit held that there was not clear and convincing evidence of § 103 obviousness of the patented discovery and its use to produce carbon fiber sheets of pre-selected homogeneous electrical resistance.  The Federal Circuit also held that Zoltec did not improperly broaden the claims by amendment during the reissue, considering that the reissue Examiner has similarly found no improper broadening of the patent claims, wherein the patent owner substituted a preparatory step, known to those skilled in the art at the time of the invention, with a requirement to start with the product of that known preparatory step.

Patent owner Zoltek sought compensation from the United States for the use of the patented method of producing carbon fiber sheet products claimed in reissued patent Re 34,162.  The suit was originally filed 10 years ago, in March 1996, alleging that the process used to produce carbon fiber sheet materials for the B-2 Bomber and the F-22 Fighter Plane infringed the ‘162 Patent.  The present decision is the third appeal in this case.  In the prior remand, the CFC held the asserted claims invalid on the grounds of obviousness and inadequate written description.  

The Federal Circuit found that the CFC acted within its discretion in limiting the trial initially to the issues of validity due to the circumstances of the case, taking into account the government’s official invocation of state secret privilege.  Accordingly, the CFC just looked at the validity of the ‘162 Patent.  

As for written description argument under §112, the CFC had held that the reissue impermissibly broadened the patented process by reducing the number of steps required for infringement.  The reissue eliminated the preparation of the starting material.  However, the patent’s specification described the preparation of the starting material and stated that it was commercially available.  The Federal Circuit reversed and found that the reissue was not invalid for failure to meet the written description requirement of §112.

Figure 4 of the ‘162 patent shows the foundation discovery of resistivity as a function of carbonizing temperature and was not previously known.  

In regard to the obviousness claim under §103, the Federal Circuit found that neither the government’s attorney argument, nor the government’s expert Dr. Sullivan’s testimony, nor the opinion of the CFC, points to any suggestion in the prior art to select the data selected by Dr. Sullivan and create the mathematical formula to construct a graph to track Figure 4.  Even Dr. Sullivan called his reconstruction “somewhat arbitrary.”  The Federal Circuit reversed and found there was not clear and convincing evidence of obviousness of the invention of the ‘162 Patent.   

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