Thursday, August 5, 2010



  • Burden of Proof

  • While the burden typically rests with the patentee to prove infringement, the law makes exceptions. In actions alleging infringement of a process claim under § 271(g), there is a rebuttable presumption that the imported product was made from the patented process if the court finds: “(1) that a substantial likelihood exists that the product was made by the patented process, and (2) that the plaintiff has made a reasonable effort to determine the process actually used in the production of the product and was unable to so determine.” 35 U.S.C. § 295. If both conditions are met, “the product shall be presumed to have been so made, and the burden of establishing that the product was not made by the process shall be on the party asserting that it was not so made.” Id. Because the accused infringer is in a far better position to determine the actual manufacturing process than the patentee, fairness dictates that the accused, likely the only party able to obtain this information, reveal this process or face the presumption of infringement.

  • Commercial Embodiment:


  • [W]hen a commercial product meets all of the claim limitations, then a comparison to that product may support a finding of infringement.

  • Doctrine of Equivalents (numerical ranges)

  • [T]he doctrine of equivalents can apply to a range—a numerical limitation in a claim. The mere existence of a numerical value or range in a claim, absent more limiting language in the intrinsic record, does not preclude application of the doctrine of equivalents.

  • The proper inquiry is whether the accused value is insubstantially different from the claimed value.


  • Means-Plus-Function

  • “Literal infringement of a means-plus-function limitation requires that the relevant structure in the accused device perform the identical function recited in the claim and be identical or equivalent to the corresponding structure in the specification.”

  • “A structure in the accused device constitutes an equivalent to the corresponding structure in the patent only if the accused structure performs the identical function in substantially the same way, with substantially the same result.”

Wednesday, August 4, 2010

Prosecution History Estoppel

  • Where an amendment narrows the scope of the claims, and that amendment is adopted for a substantial reason related to patentability, the amendment gives rise to a presumption of surrender for all equivalents that reside in the territory between the original claim and the amended claim.
  • Although there is no hard-and-fast test for what is and what is not a tangential relation, it is clear that an amendment made to avoid prior art that contains the equivalent in question is not tangential.
  • The applicability of prosecution history estoppel does not completely bar the benefit of the doctrine of equivalents from all litigation related to the amended claim. The scope of the estoppel must fit the nature of the narrowing amendment. A district court must look to the specifics of the amendment and the rejection that provoked the amendment to determine whether estoppel precludes the particular doctrine of equivalents argument being made.