Despite a long history of precedence, chemical “range” cases still generate contested issues and inter partes review proceedings are no different. The Board considered an issue relative to an overlap of ranges in E Ink Corporation v. Research Frontiers Incorporated, IPR2014-00422, involving US Pat. No. 6,606,185. Because the prior art cited by Petitioner did not disclose, with sufficient specificity, ranges that overlapped with the claimed ranges of the ‘185 invention, the Petition seeking IPR was denied.

The ‘453 patent relates generally to films comprising heat-reflective particles, and key limitations of the claimed invention recite ranges for particular particle sizes. Of relevance to the range issue of this article, claim 1 of the challenged patent requires “particles hav[ing] an average length in a range between about 1 micron and about 50 nanometers.”

Both Patent Owner and Petitioner acknowledged that the art cited by Petitioner described particle size ranges that overlapped with the ranges claimed in the ‘185 patent.  Specifically, the prior art disclosed “anisometric particles having an average particle size of about 0.2 microns or less, preferably about 0.1 microns or less.” Despite this overlap, Patent Owner argued that (1) the cited art failed to recognize the importance of the claimed lower limit of the ‘185 particle size range; and (2) that the overlap between the art-described ranges and the ‘185 claimed ranges were insufficient for anticipation.

The Board agreed, finding that the cited art did not disclose a lower limit to a particle size range, as required by the ‘185 patent.  The Board also found that the lower limit of the particle size range was key to the ‘185 invention, as Patent Owner emphasized that particle sizes smaller than the lower limit could lead to problems with the invention.  Therefore, because of lack of disclosure of a lower limit to the particle size range, and because the cited art’s range was larger than the ‘185 patent, the Board found that there was no anticipation of the ‘185 claims.

Accordingly, the Board was unpersuaded by Patent Challenger’s range-based anticipation arguments, and denied the petition for inter partes review.