In INEOS USA LLC v. BERRY PLASTICS CORP., Appeal No. 2014-1540, the Federal Circuit held that, when a patent claims a range, if the patentee is unable to establish the criticality of the claimed range, then the claimed range is anticipated by a prior art reference if the reference describes the claimed range with sufficient specificity.

Ineos’s patent recites four specific limitations, with each limitation claiming a range:

  1. At least 94.5%
  2. 0.05 to 0.5%
  3. 0 to 0.15%
  4. 0 to 5%

Ineos sued Berry Plastics for infringement. The district court granted summary judgment that the patent was invalid as anticipated by the prior art.

The Federal Circuit affirmed.  The prior art disclosed limitation 1. The prior art also disclosed the range of 0.1 to 5%, which overlaps with limitation 2. However, the prior art did not disclose limitation 3 and 4. Nevertheless, limitations 3 and 4 were found to be optional, and therefore, any prior art did not require anticipating limitations 3 and 4. 

Regarding limitation 2, the prior art disclosed a range that overlapped the claimed limitation. The Federal Circuit emphasized that, when a patent claims a range, that range is anticipated by a prior art reference if the reference discloses a point within the range. However, Berry Plastics did not disclose a point, but rather a range. Thus, as is the situation in this case, if the prior art discloses its own range, then the prior art is only anticipatory if it describes the claimed range with sufficient specificity so that a reasonable fact finder could conclude that there is no reasonable difference in how the invention operates over the ranges. Nevertheless, anticipation can be overcome if the patentee is able establish that the claimed range was critical to the invention. Here, however, Ineos was unable to establish the criticality of the claimed range.