In an inter partes reexamination proceeding, the patentee amended its claims to add a negative limitation: “the chip selects . . . are DDR chip selects that are not CAS, RAS, or bank address signals.”  The petitioner objected to this amendment on the grounds that it was not supported by the specification and therefore violated the written description requirement.  The PTO, however, affirmed the examiner’s decision and the petitioner appealed to the Federal Circuit.  The Federal Circuit held that the negative amendment did not violate the written description requirement, and, more specifically, held that, not only are negative limitations adequately supported when the “specification describes a reason to exclude the relevant limitation” (Santarus, Inc. v. Par Pharm., Inc., 694 F.3d 1344, 1351 (Fed. Cir. 2012)), but are also supported when the specification properly describes alternative features without articulating advantages or disadvantages of each feature, which can constitute a “reason to exclude.”  Applying these rules to the facts, the court held that substantial evidence supported the PTAB’s finding that the amended claims were adequately supported by the specification, and therefore the court affirmed. 

Inphi Corp. v. Netlist, Inc., Case Nos. 2015-1179 (November 13, 2015); Opinion by: O’Malley, joined by Reyna and Chen; Appealed From: Patent Trial and Appeal Board. Read the full opinion here.

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